Index: /trunk/src/libs/libpng-1.6.45/ANNOUNCE
===================================================================
--- /trunk/src/libs/libpng-1.6.45/ANNOUNCE	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/ANNOUNCE	(revision 107811)
@@ -0,0 +1,63 @@
+libpng 1.6.43 - February 23, 2024
+=================================
+
+This is a public release of libpng, intended for use in production code.
+
+
+Files available for download
+----------------------------
+
+Source files with LF line endings (for Unix/Linux):
+
+ * libpng-1.6.43.tar.xz (LZMA-compressed, recommended)
+ * libpng-1.6.43.tar.gz (deflate-compressed)
+
+Source files with CRLF line endings (for Windows):
+
+ * lpng1643.7z (LZMA-compressed, recommended)
+ * lpng1643.zip (deflate-compressed)
+
+Other information:
+
+ * README.md
+ * LICENSE.md
+ * AUTHORS.md
+ * TRADEMARK.md
+
+
+Changes from version 1.6.42 to version 1.6.43
+---------------------------------------------
+
+ * Fixed the row width check in png_check_IHDR().
+   This corrected a bug that was specific to the 16-bit platforms,
+   and removed a spurious compiler warning from the 64-bit builds.
+   (Reported by Jacek Caban; fixed by John Bowler)
+ * Added eXIf chunk support to the push-mode reader in pngpread.c.
+   (Contributed by Chris Blume)
+ * Added contrib/pngexif for the benefit of the users who would like
+   to inspect the content of eXIf chunks.
+ * Added contrib/conftest/basic.dfa, a basic build-time configuration.
+   (Contributed by John Bowler)
+ * Fixed a preprocessor condition in pngread.c that broke build-time
+   configurations like contrib/conftest/pngcp.dfa.
+   (Contributed by John Bowler)
+ * Added CMake build support for LoongArch LSX.
+   (Contributed by GuXiWei)
+ * Fixed a CMake build error that occurred under a peculiar state of the
+   dependency tree. This was a regression introduced in libpng-1.6.41.
+   (Contributed by Dan Rosser)
+ * Marked the installed libpng headers as system headers in CMake.
+   (Contributed by Benjamin Buch)
+ * Updated the build support for RISCOS.
+   (Contributed by Cameron Cawley)
+ * Updated the makefiles to allow cross-platform builds to initialize
+   conventional make variables like AR and ARFLAGS.
+ * Added various improvements to the CI scripts in areas like version
+   consistency verification and text linting.
+ * Added version consistency verification to pngtest.c also.
+
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net.
+Subscription is required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe.
Index: /trunk/src/libs/libpng-1.6.45/AUTHORS
===================================================================
--- /trunk/src/libs/libpng-1.6.45/AUTHORS	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/AUTHORS	(revision 107811)
@@ -0,0 +1,61 @@
+PNG REFERENCE LIBRARY AUTHORS
+=============================
+
+This is the list of PNG Reference Library ("libpng") Contributing
+Authors, for copyright and licensing purposes.
+
+ * Adam Richter
+ * Andreas Dilger
+ * Chris Blume
+ * Cosmin Truta
+ * Dave Martindale
+ * Eric S. Raymond
+ * Gilles Vollant
+ * Glenn Randers-Pehrson
+ * Greg Roelofs
+ * Guy Eric Schalnat
+ * James Yu
+ * John Bowler
+ * Kevin Bracey
+ * Magnus Holmgren
+ * Mandar Sahastrabuddhe
+ * Mans Rullgard
+ * Matt Sarett
+ * Mike Klein
+ * Pascal Massimino
+ * Paul Schmidt
+ * Philippe Antoine
+ * Qiang Zhou
+ * Sam Bushell
+ * Samuel Williams
+ * Simon-Pierre Cadieux
+ * Tim Wegner
+ * Tom Lane
+ * Tom Tanner
+ * Vadim Barkov
+ * Willem van Schaik
+ * Zhijie Liang
+ * Apple Inc.
+    - Zixu Wang (王子旭)
+ * Arm Holdings
+    - Richard Townsend
+ * Google Inc.
+    - Dan Field
+    - Leon Scroggins III
+    - Matt Sarett
+    - Mike Klein
+    - Sami Boukortt
+    - Wan-Teh Chang
+ * Loongson Technology Corporation Ltd.
+    - GuXiWei (顾希伟)
+    - JinBo (金波)
+    - ZhangLixia (张利霞)
+
+The build projects, the build scripts, the test scripts, and other
+files in the "projects", "scripts" and "tests" directories, have
+other copyright owners, but are released under the libpng license.
+
+Some files in the "ci" and "contrib" directories, as well as some
+of the tools-generated files that are distributed with libpng, have
+other copyright owners, and are released under other open source
+licenses.
Index: /trunk/src/libs/libpng-1.6.45/CHANGES
===================================================================
--- /trunk/src/libs/libpng-1.6.45/CHANGES	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/CHANGES	(revision 107811)
@@ -0,0 +1,6202 @@
+CHANGES - changes for libpng
+
+version 0.1 [March 29, 1995]
+  initial work-in-progress release
+
+version 0.2 [April 1, 1995]
+  added reader into png.h
+  fixed small problems in stub file
+
+version 0.3 [April 8, 1995]
+  added pull reader
+  split up pngwrite.c to several files
+  added pnglib.txt
+  added example.c
+  cleaned up writer, adding a few new transformations
+  fixed some bugs in writer
+  interfaced with zlib 0.5
+  added K&R support
+  added check for 64 KB blocks for 16 bit machines
+
+version 0.4 [April 26, 1995]
+  cleaned up code and commented code
+  simplified time handling into png_time
+  created png_color_16 and png_color_8 to handle color needs
+  cleaned up color type defines
+  fixed various bugs
+  made various names more consistent
+  interfaced with zlib 0.71
+  cleaned up zTXt reader and writer (using zlib's Reset functions)
+  split transformations into pngrtran.c and pngwtran.c
+
+version 0.5 [April 30, 1995]
+  interfaced with zlib 0.8
+  fixed many reading and writing bugs
+  saved using 3 spaces instead of tabs
+
+version 0.6 [May 1, 1995]
+  first beta release
+  added png_large_malloc() and png_large_free()
+  added png_size_t
+  cleaned up some compiler warnings
+  added png_start_read_image()
+
+version 0.7 [June 24, 1995]
+  cleaned up lots of bugs
+  finished dithering and other stuff
+  added test program
+  changed name from pnglib to libpng
+
+version 0.71 [June 26, 1995]
+  changed pngtest.png for zlib 0.93
+  fixed error in libpng.txt and example.c
+
+version 0.8 [August 20, 1995]
+  cleaned up some bugs
+  added png_set_filler()
+  split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
+  added #define's to remove unwanted code
+  moved png_info_init() to png.c
+  added old_size into png_realloc()
+  added functions to manually set filtering and compression info
+  changed compression parameters based on image type
+  optimized filter selection code
+  added version info
+  changed external functions passing floats to doubles (k&r problems?)
+  put all the configurable stuff in pngconf.h
+  enabled png_set_shift to work with paletted images on read
+  added png_read_update_info() - updates info structure with transformations
+
+Version 0.81 [August, 1995]
+  incorporated Tim Wegner's medium model code (thanks, Tim)
+
+Version 0.82 [September, 1995]
+  [unspecified changes]
+
+Version 0.85 [December, 1995]
+  added more medium model code (almost everything's a far)
+  added i/o, error, and memory callback functions
+  fixed some bugs (16-bit, 4-bit interlaced, etc.)
+  added first run progressive reader (barely tested)
+
+Version 0.86 [January, 1996]
+  fixed bugs
+  improved documentation
+
+Version 0.87 [January, 1996]
+  fixed medium model bugs
+  fixed other bugs introduced in 0.85 and 0.86
+  added some minor documentation
+
+Version 0.88 [January, 1996]
+  fixed progressive bugs
+  replaced tabs with spaces
+  cleaned up documentation
+  added callbacks for read/write and warning/error functions
+
+Version 0.89 [June 5, 1996]
+  Added new initialization API to make libpng work better with shared libs
+    we now have png_create_read_struct(), png_create_write_struct(),
+    png_create_info_struct(), png_destroy_read_struct(), and
+    png_destroy_write_struct() instead of the separate calls to
+    malloc and png_read_init(), png_info_init(), and png_write_init()
+  Changed warning/error callback functions to fix bug - this means you
+    should use the new initialization API if you were using the old
+    png_set_message_fn() calls, and that the old API no longer exists
+    so that people are aware that they need to change their code
+  Changed filter selection API to allow selection of multiple filters
+    since it didn't work in previous versions of libpng anyways
+  Optimized filter selection code
+  Fixed png_set_background() to allow using an arbitrary RGB color for
+    paletted images
+  Fixed gamma and background correction for paletted images, so
+    png_correct_palette is not needed unless you are correcting an
+    external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
+    in pngconf.h) - if nobody uses this, it may disappear in the future.
+  Fixed bug with Borland 64K memory allocation (Alexander Lehmann)
+  Fixed bug in interlace handling (Smarasderagd, I think)
+  Added more error checking for writing and image to reduce invalid files
+  Separated read and write functions so that they won't both be linked
+    into a binary when only reading or writing functionality is used
+  New pngtest image also has interlacing and zTXt
+  Updated documentation to reflect new API
+
+Version 0.89c [June 17, 1996]
+  Bug fixes.
+
+Version 0.90 [January, 1997]
+  Made CRC errors/warnings on critical and ancillary chunks configurable
+  libpng will use the zlib CRC routines by (compile-time) default
+  Changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
+  Added external C++ wrapper statements to png.h (Gilles Dauphin)
+  Allow PNG file to be read when some or all of file signature has already
+    been read from the beginning of the stream.  ****This affects the size
+    of info_struct and invalidates all programs that use a shared libpng****
+  Fixed png_filler() declarations
+  Fixed? background color conversions
+  Fixed order of error function pointers to match documentation
+  Current chunk name is now available in png_struct to reduce the number
+    of nearly identical error messages (will simplify multi-lingual
+    support when available)
+  Try to get ready for unknown-chunk callback functions:
+    - previously read critical chunks are flagged, so the chunk handling
+      routines can determine if the chunk is in the right place
+    - all chunk handling routines have the same prototypes, so we will
+      be able to handle all chunks via a callback mechanism
+  Try to fix Linux "setjmp" buffer size problems
+  Removed png_large_malloc, png_large_free, and png_realloc functions.
+
+Version 0.95 [March, 1997]
+  Fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
+  Fixed bug in PNG file signature compares when start != 0
+  Changed parameter type of png_set_filler(...filler...) from png_byte
+    to png_uint_32
+  Added test for MACOS to ensure that both math.h and fp.h are not #included
+  Added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
+  Added "packswap" transformation, which changes the endianness of
+    packed-pixel bytes (Kevin Bracey)
+  Added "strip_alpha" transformation, which removes the alpha channel of
+    input images without using it (not necessarily a good idea)
+  Added "swap_alpha" transformation, which puts the alpha channel in front
+    of the color bytes instead of after
+  Removed all implicit variable tests which assume NULL == 0 (I think)
+  Changed several variables to "png_size_t" to show 16/32-bit limitations
+  Added new pCAL chunk read/write support
+  Added experimental filter selection weighting (Greg Roelofs)
+  Removed old png_set_rgbx() and png_set_xrgb() functions that have been
+    obsolete for about 2 years now (use png_set_filler() instead)
+  Added macros to read 16- and 32-bit ints directly from buffer, to be
+    used only on those systems that support it (namely PowerPC and 680x0)
+    With some testing, this may become the default for MACOS/PPC systems.
+  Only calculate CRC on data if we are going to use it
+  Added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
+  Added macros for simple libpng debugging output selectable at compile time
+  Removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
+  More description of info_struct in libpng.txt and png.h
+  More instructions in example.c
+  More chunk types tested in pngtest.c
+  Renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
+    png_set_<chunk>.  We now have corresponding png_get_<chunk>
+    functions in pngget.c to get information in info_ptr.  This isolates
+    the application from the internal organization of png_info_struct
+    (good for shared library implementations).
+
+Version 0.96 [May, 1997]
+  Fixed serious bug with < 8bpp images introduced in 0.95
+  Fixed 256-color transparency bug (Greg Roelofs)
+  Fixed up documentation (Greg Roelofs, Laszlo Nyul)
+  Fixed "error" in pngconf.h for Linux setjmp() behavior
+  Fixed DOS medium model support (Tim Wegner)
+  Fixed png_check_keyword() for case with error in static string text
+  Added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
+  Added typecasts to quiet compiler errors
+  Added more debugging info
+
+Version 0.97 [January, 1998]
+  Removed PNG_USE_OWN_CRC capability
+  Relocated png_set_crc_action from pngrutil.c to pngrtran.c
+  Fixed typecasts of "new_key", etc. (Andreas Dilger)
+  Added RFC 1152 [sic] date support
+  Fixed bug in gamma handling of 4-bit grayscale
+  Added 2-bit grayscale gamma handling (Glenn R-P)
+  Added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
+  Minor corrections in libpng.txt
+  Added simple sRGB support (Glenn R-P)
+  Easier conditional compiling, e.g.,
+    define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
+    all configurable options can be selected from command line instead
+    of having to edit pngconf.h (Glenn R-P)
+  Fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
+  Added more conditions for png_do_background, to avoid changing
+    black pixels to background when a background is supplied and
+    no pixels are transparent
+  Repaired PNG_NO_STDIO behavior
+  Tested NODIV support and made it default behavior (Greg Roelofs)
+  Added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
+  Regularized version numbering scheme and bumped shared-library major
+    version number to 2 to avoid problems with libpng 0.89 apps
+    (Greg Roelofs)
+
+Version 0.98 [January, 1998]
+  Cleaned up some typos in libpng.txt and in code documentation
+  Fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
+  Cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
+  Changed recommendation about file_gamma for PC images to .51 from .45,
+    in example.c and libpng.txt, added comments to distinguish between
+    screen_gamma, viewing_gamma, and display_gamma.
+  Changed all references to RFC1152 to read RFC1123 and changed the
+    PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
+  Added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
+  Changed srgb_intent from png_byte to int to avoid compiler bugs
+
+Version 0.99 [January 30, 1998]
+  Free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
+  Fixed a longstanding "packswap" bug in pngtrans.c
+  Fixed some inconsistencies in pngconf.h that prevented compiling with
+    PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
+  Fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
+  Changed recommendation about file_gamma for PC images to .50 from .51 in
+    example.c and libpng.txt, and changed file_gamma for sRGB images to .45
+  Added a number of functions to access information from the png structure
+    png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
+  Added TARGET_MACOS similar to zlib-1.0.8
+  Define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
+  Added type casting to all png_malloc() function calls
+
+Version 0.99a [January 31, 1998]
+  Added type casts and parentheses to all returns that return a value.(Tim W.)
+
+Version 0.99b [February 4, 1998]
+  Added type cast png_uint_32 on malloc function calls where needed.
+  Changed type of num_hist from png_uint_32 to int (same as num_palette).
+  Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
+  Renamed makefile.elf to makefile.lnx.
+
+Version 0.99c [February 7, 1998]
+  More type casting.  Removed erroneous overflow test in pngmem.c.
+  Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
+  Added UNIX manual pages libpng.3 (incorporating libpng.txt) and  png.5.
+
+Version 0.99d [February 11, 1998]
+  Renamed "far_to_near()" "png_far_to_near()"
+  Revised libpng.3
+  Version 99c "buffered" operations didn't work as intended.  Replaced them
+    with png_memcpy_check() and png_memset_check().
+  Added many "if (png_ptr == NULL) return" to quell compiler warnings about
+    unused png_ptr, mostly in pngget.c and pngset.c.
+  Check for overlength tRNS chunk present when indexed-color PLTE is read.
+  Cleaned up spelling errors in libpng.3/libpng.txt
+  Corrected a problem with png_get_tRNS() which returned undefined trans array
+
+Version 0.99e [February 28, 1998]
+  Corrected png_get_tRNS() again.
+  Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
+  Touched up example.c to make more of it compileable, although the entire
+    file still can't be compiled (Willem van Schaik)
+  Fixed a bug in png_do_shift() (Bryan Tsai)
+  Added a space in png.h prototype for png_write_chunk_start()
+  Replaced pngtest.png with one created with zlib 1.1.1
+  Changed pngtest to report PASS even when file size is different (Jean-loup G.)
+  Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
+
+Version 0.99f [March 5, 1998]
+  Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
+  Moved makefiles into a "scripts" directory, and added INSTALL instruction file
+  Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
+  Added pointers to "note on libpng versions" in makefile.lnx and README
+  Added row callback feature when reading and writing nonprogressive rows
+    and added a test of this feature in pngtest.c
+  Added user transform callbacks, with test of the feature in pngtest.c
+
+Version 0.99g [March 6, 1998, morning]
+  Minor changes to pngtest.c to suppress compiler warnings.
+  Removed "beta" language from documentation.
+
+Version 0.99h [March 6, 1998, evening]
+  Minor changes to previous minor changes to pngtest.c
+  Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
+    and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
+  Added user transform capability
+
+Version 1.00 [March 7, 1998]
+  Changed several typedefs in pngrutil.c
+  Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
+  Replaced "while(1)" with "for(;;)"
+  Added PNGARG() to prototypes in pngtest.c and removed some prototypes
+  Updated some of the makefiles (Tom Lane)
+  Changed some typedefs (s_start, etc.) in pngrutil.c
+  Fixed dimensions of "short_months" array in pngwrite.c
+  Replaced ansi2knr.c with the one from jpeg-v6
+
+Version 1.0.0 [March 8, 1998]
+  Changed name from 1.00 to 1.0.0 (Adam Costello)
+  Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
+
+Version 1.0.0a [March 9, 1998]
+  Fixed three bugs in pngrtran.c to make gamma+background handling consistent
+    (Greg Roelofs)
+  Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
+    for major, minor, and bugfix releases.  This is 10001. (Adam Costello,
+    Tom Lane)
+  Make months range from 1-12 in png_convert_to_rfc1123
+
+Version 1.0.0b [March 13, 1998]
+  Quieted compiler complaints about two empty "for" loops in pngrutil.c
+  Minor changes to makefile.s2x
+  Removed #ifdef/#endif around a png_free() in pngread.c
+
+Version 1.0.1 [March 14, 1998]
+  Changed makefile.s2x to reduce security risk of using a relative pathname
+  Fixed some typos in the documentation (Greg).
+  Fixed a problem with value of "channels" returned by png_read_update_info()
+
+Version 1.0.1a [April 21, 1998]
+  Optimized Paeth calculations by replacing abs() function calls with intrinsics
+  plus other loop optimizations. Improves avg decoding speed by about 20%.
+  Commented out i386istic "align" compiler flags in makefile.lnx.
+  Reduced the default warning level in some makefiles, to make them consistent.
+  Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
+  Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
+  Added grayscale and 16-bit capability to png_do_read_filler().
+  Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
+    too large when writing an image with bit_depth < 8 (Bob Dellaca).
+  Corrected some bugs in the experimental weighted filtering heuristics.
+  Moved a misplaced pngrutil code block that truncates tRNS if it has more
+    than num_palette entries -- test was done before num_palette was defined.
+  Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
+  Changed compiler flags in makefile.wat for better optimization
+    (Pawel Mrochen).
+
+Version 1.0.1b [May 2, 1998]
+  Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
+  Relocated the png_composite macros from pngrtran.c to png.h (Greg).
+  Added makefile.sco (contributed by Mike Hopkirk).
+  Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
+  Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
+  More work on the Paeth-filtering, achieving imperceptible speedup
+    (A Kleinert).
+  More work on loop optimization which may help when compiled with C++
+    compilers.
+  Added warnings when people try to use transforms they've defined out.
+  Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
+  Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
+
+Version 1.0.1c [May 11, 1998]
+  Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
+    filler bytes should have been 0xff instead of 0xf.
+  Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
+  Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
+    out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
+  Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
+    for consistency, in pngconf.h
+  Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
+    to remove unwanted capabilities via the compile line
+  Made some corrections to grammar (which, it's) in documentation (Greg).
+  Corrected example.c, use of row_pointers in png_write_image().
+
+Version 1.0.1d [May 24, 1998]
+  Corrected several statements that used side effects illegally in pngrutil.c
+    and pngtrans.c, that were introduced in version 1.0.1b
+  Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
+  More corrections to example.c, use of row_pointers in png_write_image()
+    and png_read_rows().
+  Added pngdll.mak and pngdef.pas to scripts directory, contributed by
+    Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
+  Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
+  Changed several loops from count-down to count-up, for consistency.
+
+Version 1.0.1e [June 6, 1998]
+  Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
+    added warnings when people try to set png_read_fn and png_write_fn in
+    the same structure.
+  Added a test such that png_do_gamma will be done when num_trans==0
+    for truecolor images that have defined a background.  This corrects an
+    error that was introduced in libpng-0.90 that can cause gamma processing
+    to be skipped.
+  Added tests in png.h to include "trans" and "trans_values" in structures
+    when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
+  Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
+  Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
+  Added capability for user-provided malloc_fn() and free_fn() functions,
+    and revised pngtest.c to demonstrate their use, replacing the
+    PNGTEST_DEBUG_MEM feature.
+  Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
+
+Version 1.0.2 [June 14, 1998]
+  Fixed two bugs in makefile.bor .
+
+Version 1.0.2a [December 30, 1998]
+  Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
+  Fixed a bug in png_do_filler() that made it fail to write filler bytes in
+    the left-most pixel of each row (Kevin Bracey).
+  Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
+    in pngtest.c (Duncan Simpson).
+  Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
+    even when no tIME chunk was present in the source file.
+  Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
+  Fixed a problem in png_read_push_finish_row(), which would not skip some
+    passes that it should skip, for images that are less than 3 pixels high.
+  Interchanged the order of calls to png_do_swap() and png_do_shift()
+    in pngwtran.c (John Cromer).
+  Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
+  Changed "bad adaptive filter type" from error to warning in pngrutil.c .
+  Fixed a documentation error about default filtering with 8-bit indexed-color.
+  Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
+    (L. Peter Deutsch).
+  Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
+  Added png_get_copyright() and png_get_header_version() functions.
+  Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
+  Added information about debugging in libpng.txt and libpng.3 .
+  Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and
+    makefile.sco.
+  Removed lines after Dynamic Dependencies" in makefile.aco .
+  Revised makefile.dec to make a shared library (Jeremie Petit).
+  Removed trailing blanks from all files.
+
+Version 1.0.2a [January 6, 1999]
+  Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
+  Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
+  Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
+  Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
+    which is obsolete.
+
+Version 1.0.3 [January 14, 1999]
+  Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
+  Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
+
+Version 1.0.3a [August 12, 1999]
+  Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
+    if an attempt is made to read an interlaced image when it's not supported.
+  Added check if png_ptr->trans is defined before freeing it in pngread.c
+  Modified the Y2K statement to include versions back to version 0.71
+  Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
+  Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
+  Replaced leading blanks with tab characters in makefile.hux
+  Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
+  Changed (float)red and (float)green to (double)red, (double)green
+    in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
+  Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
+  Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
+  Updated documentation to refer to the PNG-1.2 specification.
+  Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
+    in makefile.knr, INSTALL, and README (L. Peter Deutsch)
+  Fixed bugs in calculation of the length of rowbytes when adding alpha
+    channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
+  Added function png_set_user_transform_info() to store user_transform_ptr,
+    user_depth, and user_channels into the png_struct, and a function
+    png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
+  Added function png_set_empty_plte_permitted() to make libpng useable
+    in MNG applications.
+  Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
+  Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
+    consistent with PNG-1.2, and allow variance of 500 before complaining.
+  Added assembler code contributed by Intel in file pngvcrd.c and modified
+    makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation,
+    Gilles Vollant)
+  Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
+  Added some aliases for png_set_expand() in pngrtran.c, namely
+    png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
+    (Greg Roelofs, in "PNG: The Definitive Guide").
+  Added makefile.beo for BEOS on X86, contributed by Sander Stok.
+
+Version 1.0.3b [August 26, 1999]
+  Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
+  Changed leading blanks to tabs in all makefiles.
+  Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
+  Made alternate versions of  png_set_expand() in pngrtran.c, namely
+    png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
+    (Greg Roelofs, in "PNG: The Definitive Guide").  Deleted the 1.0.3a aliases.
+  Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
+  Revised calculation of num_blocks in pngmem.c to avoid a potentially
+    negative shift distance, whose results are undefined in the C language.
+  Added a check in pngset.c to prevent writing multiple tIME chunks.
+  Added a check in pngwrite.c to detect invalid small window_bits sizes.
+
+Version 1.0.3d [September 4, 1999]
+  Fixed type casting of igamma in pngrutil.c
+  Added new png_expand functions to scripts/pngdef.pas and pngos2.def
+  Added a demo read_user_transform_fn that examines the row filters in pngtest.c
+
+Version 1.0.4 [September 24, 1999, not distributed publicly]
+  Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
+  Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
+  Made several minor corrections to pngtest.c
+  Renamed the makefiles with longer but more user friendly extensions.
+  Copied the PNG copyright and license to a separate LICENSE file.
+  Revised documentation, png.h, and example.c to remove reference to
+    "viewing_gamma" which no longer appears in the PNG specification.
+  Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
+  Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
+  Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
+    assembler code) and makefile.vcwin32 (doesn't).
+  Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
+  Added a copy of pngnow.png to the distribution.
+
+Version 1.0.4a [September 25, 1999]
+  Increase max_pixel_depth in pngrutil.c if a user transform needs it.
+  Changed several division operations to right-shifts in pngvcrd.c
+
+Version 1.0.4b [September 30, 1999]
+  Added parentheses in line 3732 of pngvcrd.c
+  Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
+
+Version 1.0.4c [October 1, 1999]
+  Added a "png_check_version" function in png.c and pngtest.c that will generate
+    a helpful compiler error if an old png.h is found in the search path.
+  Changed type of png_user_transform_depth|channels from int to png_byte.
+  Added "Libpng is OSI Certified Open Source Software" statement to png.h
+
+Version 1.0.4d [October 6, 1999]
+  Changed 0.45 to 0.45455 in png_set_sRGB()
+  Removed unused PLTE entries from pngnow.png
+  Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
+
+Version 1.0.4e [October 10, 1999]
+  Fixed sign error in pngvcrd.c (Greg Roelofs)
+  Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
+
+Version 1.0.4f [October 15, 1999]
+  Surrounded example.c code with #if 0 .. #endif to prevent people from
+    inadvertently trying to compile it.
+  Changed png_get_header_version() from a function to a macro in png.h
+  Added type casting mostly in pngrtran.c and pngwtran.c
+  Removed some pointless "ptr = NULL" in pngmem.c
+  Added a "contrib" directory containing the source code from Greg's book.
+
+Version 1.0.5 [October 15, 1999]
+  Minor editing of the INSTALL and README files.
+
+Version 1.0.5a [October 23, 1999]
+  Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
+  Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
+  Further optimization and bugfix of pngvcrd.c
+  Revised pngset.c so that it does not allocate or free memory in the user's
+    text_ptr structure.  Instead, it makes its own copy.
+  Created separate write_end_info_struct in pngtest.c for a more severe test.
+  Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
+
+Version 1.0.5b [November 23, 1999]
+  Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
+    PNG_FLAG_WROTE_tIME from flags to mode.
+  Added png_write_info_before_PLTE() function.
+  Fixed some typecasting in contrib/gregbook/*.c
+  Updated scripts/makevms.com and added makevms.com to contrib/gregbook
+    and contrib/pngminus (Martin Zinser)
+
+Version 1.0.5c [November 26, 1999]
+  Moved png_get_header_version from png.h to png.c, to accommodate ansi2knr.
+  Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
+    accommodate making DLL's: Moved usr_png_ver from global variable to function
+    png_get_header_ver() in png.c.  Moved png_sig to png_sig_bytes in png.c and
+    eliminated use of png_sig in pngwutil.c.  Moved the various png_CHNK arrays
+    into pngtypes.h.  Eliminated use of global png_pass arrays.  Declared the
+    png_CHNK and png_pass arrays to be "const".  Made the global arrays
+    available to applications (although none are used in libpng itself) when
+    PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
+  Removed some extraneous "-I" from contrib/pngminus/makefile.std
+  Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
+  Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
+
+Version 1.0.5d [November 29, 1999]
+  Add type cast (png_const_charp) two places in png.c
+  Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
+  Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
+    to applications a macro "PNG_USE_LOCAL_ARRAYS".
+  comment out (with #ifdef) all the new declarations when
+    PNG_USE_GLOBAL_ARRAYS is defined.
+  Added PNG_EXPORT_VAR macro to accommodate making DLL's.
+
+Version 1.0.5e [November 30, 1999]
+  Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
+    structure; refactored the inflate/deflate support to make adding new chunks
+    with trailing compressed parts easier in the future, and added new functions
+    png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
+    png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
+    NOTE: Applications that write text chunks MUST define png_text->lang
+    before calling png_set_text(). It must be set to NULL if you want to
+    write tEXt or zTXt chunks.  If you want your application to be able to
+    run with older versions of libpng, use
+
+      #ifdef PNG_iTXt_SUPPORTED
+         png_text[i].lang = NULL;
+      #endif
+
+  Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
+    offsets (Eric S. Raymond).
+  Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
+    PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
+    macros, leaving the separate macros also available.
+  Removed comments on #endifs at the end of many short, non-nested #if-blocks.
+
+Version 1.0.5f [December 6, 1999]
+  Changed makefile.solaris to issue a warning about potential problems when
+    the ucb "ld" is in the path ahead of the ccs "ld".
+  Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
+  Added sCAL chunk support (Eric S. Raymond).
+
+Version 1.0.5g [December 7, 1999]
+  Fixed "png_free_spallettes" typo in png.h
+  Added code to handle new chunks in pngpread.c
+  Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
+  Added "translated_key" to png_text structure and png_write_iTXt().
+  Added code in pngwrite.c to work around a newly discovered zlib bug.
+
+Version 1.0.5h [December 10, 1999]
+  NOTE: regarding the note for version 1.0.5e, the following must also
+    be included in your code:
+        png_text[i].translated_key = NULL;
+  Unknown chunk handling is now supported.
+  Option to eliminate all floating point support was added.  Some new
+    fixed-point functions such as png_set_gAMA_fixed() were added.
+  Expanded tabs and removed trailing blanks in source files.
+
+Version 1.0.5i [December 13, 1999]
+  Added some type casts to silence compiler warnings.
+  Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
+  Removed leading blanks from a #define in pngvcrd.c
+  Added some parameters to the new png_set_keep_unknown_chunks() function.
+  Added a test for up->location != 0 in the first instance of writing
+    unknown chunks in pngwrite.c
+  Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
+    prevent recursion.
+  Added png_free_hIST() function.
+  Various patches to fix bugs in the sCAL and integer cHRM processing,
+    and to add some convenience macros for use with sCAL.
+
+Version 1.0.5j [December 21, 1999]
+  Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
+    around buggy compilers.
+  Added new type "png_fixed_point" for integers that hold float*100000 values
+  Restored backward compatibility of tEXt/zTXt chunk processing:
+    Restored the first four members of png_text to the same order as v.1.0.5d.
+    Added members "lang_key" and "itxt_length" to png_text struct.  Set
+    text_length=0 when "text" contains iTXt data.  Use the "compression"
+    member to distinguish among tEXt/zTXt/iTXt types.  Added
+    PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
+    The "Note" above, about backward incompatibility of libpng-1.0.5e, no
+    longer applies.
+  Fixed png_read|write_iTXt() to read|write parameters in the right order,
+    and to write the iTXt chunk after IDAT if it appears in the end_ptr.
+  Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
+  Reversed the order of trying to write floating-point and fixed-point gAMA.
+
+Version 1.0.5k [December 27, 1999]
+  Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
+  Added png_handle_as_unknown() function (Glenn)
+  Added png_free_chunk_list() function and chunk_list and num_chunk_list members
+    of png_ptr.
+  Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
+  Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
+    about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
+  Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
+  Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
+  Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
+
+Version 1.0.5l [January 1, 2000]
+  Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
+    for setting a callback function to handle unknown chunks and for
+    retrieving the associated user pointer (Glenn).
+
+Version 1.0.5m [January 7, 2000]
+  Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
+
+Version 1.0.5n [January 9, 2000]
+  Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
+    own memory for info_ptr->palette.  This makes it safe for the calling
+    application to free its copy of the palette any time after it calls
+    png_set_PLTE().
+
+Version 1.0.5o [January 20, 2000]
+  Cosmetic changes only (removed some trailing blanks and TABs)
+
+Version 1.0.5p [January 31, 2000]
+  Renamed pngdll.mak to makefile.bd32
+  Cosmetic changes in pngtest.c
+
+Version 1.0.5q [February 5, 2000]
+  Relocated the makefile.solaris warning about PATH problems.
+  Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
+  Revised makefile.gcmmx
+  Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
+
+Version 1.0.5r [February 7, 2000]
+  Removed superfluous prototype for png_get_itxt from png.h
+  Fixed a bug in pngrtran.c that improperly expanded the background color.
+  Return *num_text=0 from png_get_text() when appropriate, and fix documentation
+    of png_get_text() in libpng.txt/libpng.3.
+
+Version 1.0.5s [February 18, 2000]
+  Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
+    new error handler that's planned for the next libpng release, and changed
+    example.c, pngtest.c, and contrib programs to use this macro.
+  Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
+  Fixed a bug in png_read_png() that caused it to fail to expand some images
+    that it should have expanded.
+  Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
+    in pngget.c
+  Changed the allocation of palette, history, and trans arrays back to
+    the version 1.0.5 method (linking instead of copying) which restores
+    backward compatibility with version 1.0.5.  Added some remarks about
+    that in example.c.  Added "free_me" member to info_ptr and png_ptr
+    and added png_free_data() function.
+  Updated makefile.linux and makefile.gccmmx to make directories conditionally.
+  Made cosmetic changes to pngasmrd.h
+  Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
+  Modified png_read_png() to allocate info_ptr->row_pointers only if it
+    hasn't already been allocated.
+
+Version 1.0.5t [March 4, 2000]
+  Changed png_jmp_env() migration aiding macro to png_jmpbuf().
+  Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
+  Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
+    PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
+  Files in contrib/gregbook were revised to use png_jmpbuf() and to select
+    a 24-bit visual if one is available, and to allow abbreviated options.
+  Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
+  Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
+
+Version 1.0.5u [March 5, 2000]
+  Simplified the code that detects old png.h in png.c and pngtest.c
+  Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
+  Increased precision of rgb_to_gray calculations from 8 to 15 bits and
+    added png_set_rgb_to_gray_fixed() function.
+  Added makefile.bc32 (32-bit Borland C++, C mode)
+
+Version 1.0.5v [March 11, 2000]
+  Added some parentheses to the png_jmpbuf macro definition.
+  Updated references to the zlib home page, which has moved to freesoftware.com.
+  Corrected bugs in documentation regarding png_read_row() and png_write_row().
+  Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
+  Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
+    revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
+
+Version 1.0.6 [March 20, 2000]
+  Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
+  Added makefile.sggcc (SGI IRIX with gcc)
+
+Version 1.0.6d [April 7, 2000]
+  Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
+  Added data_length parameter to png_decompress_chunk() function
+  Revised documentation to remove reference to abandoned png_free_chnk functions
+  Fixed an error in png_rgb_to_gray_fixed()
+  Revised example.c, usage of png_destroy_write_struct().
+  Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
+  Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c
+  Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
+
+Version 1.0.6e [April 9, 2000]
+  Added png_data_freer() function.
+  In the code that checks for over-length tRNS chunks, added check of
+    info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
+  Minor revisions of libpng.txt/libpng.3.
+  Check for existing data and free it if the free_me flag is set, in png_set_*()
+    and png_handle_*().
+  Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
+    is defined.
+  Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
+    and mentioned the purposes of the two macros in libpng.txt/libpng.3.
+
+Version 1.0.6f [April 14, 2000]
+  Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
+  Add checks in png_set_text() for NULL members of the input text structure.
+  Revised libpng.txt/libpng.3.
+  Removed superfluous prototype for png_set_iTXt from png.h
+  Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
+  Changed several png_errors about malformed ancillary chunks to png_warnings.
+
+Version 1.0.6g [April 24, 2000]
+  Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
+  Relocated paragraph about png_set_background() in libpng.3/libpng.txt
+    and other revisions (Matthias Benckmann)
+  Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
+    png_ptr members to restore binary compatibility with libpng-1.0.5
+    (breaks compatibility with libpng-1.0.6).
+
+Version 1.0.6h [April 24, 2000]
+  Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
+    libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
+    This is a temporary change for test purposes.
+
+Version 1.0.6i [May 2, 2000]
+  Rearranged some members at the end of png_info and png_struct, to put
+    unknown_chunks_num and free_me within the original size of the png_structs
+    and free_me, png_read_user_fn, and png_free_fn within the original png_info,
+    because some old applications allocate the structs directly instead of
+    using png_create_*().
+  Added documentation of user memory functions in libpng.txt/libpng.3
+  Modified png_read_png so that it will use user_allocated row_pointers
+    if present, unless free_me directs that it be freed, and added description
+    of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
+  Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
+    1.00) members of png_struct and png_info, to regain binary compatibility
+    when you define this macro.  Capabilities lost in this event
+    are user transforms (new in version 1.0.0),the user transform pointer
+    (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
+    the high-level interface, and unknown chunks support (all new in 1.0.6).
+    This was necessary because of old applications that allocate the structs
+    directly as authors were instructed to do in libpng-0.88 and earlier,
+    instead of using png_create_*().
+  Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
+    can be used to detect codes that directly allocate the structs, and
+    code to check these modes in png_read_init() and png_write_init() and
+    generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
+    was not defined.
+  Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
+
+Version 1.0.6j [May 3, 2000]
+  Overloaded png_read_init() and png_write_init() with macros that convert
+    calls to png_read_init_2() or png_write_init_2() that check the version
+    and structure sizes.
+
+Version 1.0.7beta11 [May 7, 2000]
+  Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
+    which are no longer used.
+  Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
+    defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXt_SUPPORTED
+    is defined.
+  Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
+    overrun when old applications fill the info_ptr->text structure directly.
+  Added PNGAPI macro, and added it to the definitions of all exported functions.
+  Relocated version macro definitions ahead of the includes of zlib.h and
+    pngconf.h in png.h.
+
+Version 1.0.7beta12 [May 12, 2000]
+  Revised pngset.c to avoid a problem with expanding the png_debug macro.
+  Deleted some extraneous defines from pngconf.h
+  Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
+  Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
+  Added png_access_version_number() function.
+  Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
+  Expanded libpng.3/libpng.txt information about png_data_freer().
+
+Version 1.0.7beta14 [May 17, 2000] (beta13 was not published)
+  Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as
+    warnings instead of errors, as pngrutil.c does.
+  Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png()
+    will actually write IDATs.
+  Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32.
+  Make png_free_data() ignore its final parameter except when freeing data
+    that can have multiple instances (text, sPLT, unknowns).
+  Fixed a new bug in png_set_rows().
+  Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5.
+  Added png_set_invalid() function.
+  Fixed incorrect illustrations of png_destroy_write_struct() in example.c.
+
+Version 1.0.7beta15 [May 30, 2000]
+  Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce
+    fewer error messages.
+  Rearranged checks for Z_OK to check the most likely path first in pngpread.c
+    and pngwutil.c.
+  Added checks in pngtest.c for png_create_*() returning NULL, and mentioned
+    in libpng.txt/libpng.3 the need for applications to check this.
+  Changed names of png_default_*() functions in pngtest to pngtest_*().
+  Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32.
+  Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c
+  Set each pointer to NULL after freeing it in png_free_data().
+  Worked around a problem in pngconf.h; AIX's strings.h defines an "index"
+    macro that conflicts with libpng's png_color_16.index. (Dimitri
+    Papadapoulos)
+  Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux).
+
+Version 1.0.7beta16 [June 4, 2000]
+  Revised the workaround of AIX string.h "index" bug.
+  Added a check for overlength PLTE chunk in pngrutil.c.
+  Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer
+    indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler.
+  Added a warning in png_decompress_chunk() when it runs out of data, e.g.
+    when it tries to read an erroneous PhotoShop iCCP chunk.
+  Added PNG_USE_DLL macro.
+  Revised the copyright/disclaimer/license notice.
+  Added contrib/msvctest directory
+
+Version 1.0.7rc1 [June 9, 2000]
+  Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA  (0x0400 not 0x0200)
+  Added contrib/visupng directory (Willem van Schaik)
+
+Version 1.0.7beta18 [June 23, 2000]
+  Revised PNGAPI definition, and pngvcrd.c to work with __GCC__
+    and do not redefine PNGAPI if it is passed in via a compiler directive.
+  Revised visupng/PngFile.c to remove returns from within the Try block.
+  Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros.
+  Updated contrib/visupng/cexcept.h to version 1.0.0.
+  Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks.
+
+Version 1.0.7rc2 [June 28, 2000]
+  Updated license to include disclaimers required by UCITA.
+  Fixed "DJBPP" typo in pnggccrd.c introduced in beta18.
+
+Version 1.0.7 [July 1, 2000]
+  Revised the definition of "trans_values" in libpng.3/libpng.txt
+
+Version 1.0.8beta1 [July 8, 2000]
+  Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
+  Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
+    pngwutil.c.
+  Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
+  Removed unused "#include <assert.h>" from png.c
+  Added WindowsCE support.
+  Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment.
+
+Version 1.0.8beta2 [July 10, 2000]
+  Added project files to the wince directory and made further revisions
+    of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
+
+Version 1.0.8beta3 [July 11, 2000]
+  Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
+    for indexed-color input files to avoid potential double-freeing trans array
+    under some unusual conditions; problem was introduced in version 1.0.6f.
+  Further revisions to pngtest.c and files in the wince subdirectory.
+
+Version 1.0.8beta4 [July 14, 2000]
+  Added the files pngbar.png and pngbar.jpg to the distribution.
+  Added makefile.cygwin, and cygwin support in pngconf.h
+  Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory)
+
+Version 1.0.8rc1 [July 16, 2000]
+  Revised png_debug() macros and statements to eliminate compiler warnings.
+
+Version 1.0.8 [July 24, 2000]
+  Added png_flush() in pngwrite.c, after png_write_IEND().
+  Updated makefile.hpux to build a shared library.
+
+Version 1.0.9beta1 [November 10, 2000]
+  Fixed typo in scripts/makefile.hpux
+  Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
+  Fixed sequence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
+  Changed "cdrom.com" in documentation to "libpng.org"
+  Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
+  Changed type of "params" from voidp to png_voidp in png_read|write_png().
+  Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h.
+  Revised the 3 instances of WRITEFILE in pngtest.c.
+  Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory.
+  Updated png.rc in dll/msvc project
+  Revised makefile.dec to define and use LIBPATH and INCPATH
+  Increased size of global png_libpng_ver[] array from 12 to 18 chars.
+  Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const.
+  Removed duplicate png_crc_finish() from png_handle_bKGD() function.
+  Added a warning when application calls png_read_update_info() multiple times.
+  Revised makefile.cygwin
+  Fixed bugs in iCCP support in pngrutil.c and pngwutil.c.
+  Replaced png_set_empty_plte_permitted() with png_permit_mng_features().
+
+Version 1.0.9beta2 [November 19, 2000]
+  Renamed the "dll" subdirectory "projects".
+  Added borland project files to "projects" subdirectory.
+  Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate.
+  Add error message in png_set_compression_buffer_size() when malloc fails.
+
+Version 1.0.9beta3 [November 23, 2000]
+  Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project.
+  Removed the png_flush() in pngwrite.c that crashes some applications
+    that don't set png_output_flush_fn.
+  Added makefile.macosx and makefile.aix to scripts directory.
+
+Version 1.0.9beta4 [December 1, 2000]
+  Change png_chunk_warning to png_warning in png_check_keyword().
+  Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
+
+Version 1.0.9beta5 [December 15, 2000]
+  Added support for filter method 64 (for PNG datastreams embedded in MNG).
+
+Version 1.0.9beta6 [December 18, 2000]
+  Revised png_set_filter() to accept filter method 64 when appropriate.
+  Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
+    help prevent applications from using MNG features in PNG datastreams.
+  Added png_permit_mng_features() function.
+  Revised libpng.3/libpng.txt.  Changed "filter type" to "filter method".
+
+Version 1.0.9rc1 [December 23, 2000]
+  Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c
+  Fixed error handling of unknown compression type in png_decompress_chunk().
+  In pngconf.h, define __cdecl when _MSC_VER is defined.
+
+Version 1.0.9beta7 [December 28, 2000]
+  Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places.
+  Revised memory management in png_set_hIST and png_handle_hIST in a backward
+    compatible manner.  PLTE and tRNS were revised similarly.
+  Revised the iCCP chunk reader to ignore trailing garbage.
+
+Version 1.0.9beta8 [January 12, 2001]
+  Moved pngasmrd.h into pngconf.h.
+  Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop.
+
+Version 1.0.9beta9 [January 15, 2001]
+  Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to
+    wince and msvc project module definition files.
+  Minor revision of makefile.cygwin.
+  Fixed bug with progressive reading of narrow interlaced images in pngpread.c
+
+Version 1.0.9beta10 [January 16, 2001]
+  Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined.
+  Fixed "png_mmx_supported" typo in project definition files.
+
+Version 1.0.9beta11 [January 19, 2001]
+  Updated makefile.sgi to make shared library.
+  Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED
+    by default, for the benefit of DLL forward compatibility.  These will
+    be re-enabled in version 1.2.0.
+
+Version 1.0.9rc2 [January 22, 2001]
+  Revised cygwin support.
+
+Version 1.0.9 [January 31, 2001]
+  Added check of cygwin's ALL_STATIC in pngconf.h
+  Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
+
+Version 1.0.10beta1 [March 14, 2001]
+  Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
+  Reformatted libpng.3 to eliminate bad line breaks.
+  Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
+  Added prototype for png_mmx_support() near the top of pnggccrd.c
+  Moved some error checking from png_handle_IHDR to png_set_IHDR.
+  Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
+  Revised png_mmx_support() function in pnggccrd.c
+  Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
+  Fixed memory leak in contrib/visupng/PngFile.c
+  Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
+  Added warnings when retrieving or setting gamma=0.
+  Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
+
+Version 1.0.10rc1 [March 23, 2001]
+  Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
+    and png_strlen.
+  Revised png_mmx_supported() function in pnggccrd.c to return proper value.
+  Fixed bug in progressive reading (pngpread.c) with small images (height < 8).
+
+Version 1.0.10 [March 30, 2001]
+  Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
+  Added beos project files (Chris Herborth)
+
+Version 1.0.11beta1 [April 3, 2001]
+  Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
+  Removed a no-longer needed AIX work-around from pngconf.h
+  Changed several "//" single-line comments to C-style in pnggccrd.c
+
+Version 1.0.11beta2 [April 11, 2001]
+  Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
+  Updated scripts/pngos2.def
+
+Version 1.0.11beta3 [April 14, 2001]
+  Added checking the results of many instances of png_malloc() for NULL
+
+Version 1.0.11beta4 [April 20, 2001]
+  Undid the changes from version 1.0.11beta3.  Added a check for NULL return
+    from user's malloc_fn().
+  Removed some useless type casts of the NULL pointer.
+  Added makefile.netbsd
+
+Version 1.0.11 [April 27, 2001]
+  Revised makefile.netbsd
+
+Version 1.0.12beta1 [May 14, 2001]
+  Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
+  Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
+  Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
+  Eliminated the png_error about apps using png_read|write_init().  Instead,
+    libpng will reallocate the png_struct and info_struct if they are too small.
+    This retains future binary compatibility for old applications written for
+    libpng-0.88 and earlier.
+
+Version 1.2.0beta1 [May 6, 2001]
+  Bumped DLLNUM to 2.
+  Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED
+    by default.
+  Added runtime selection of MMX features.
+  Added png_set_strip_error_numbers function and related macros.
+
+Version 1.2.0beta2 [May 7, 2001]
+  Finished merging 1.2.0beta1 with version 1.0.11
+  Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
+
+Version 1.2.0beta3 [May 17, 2001]
+  Enabled user memory function by default.
+  Modified png_create_struct so it passes user mem_ptr to user memory allocator.
+  Increased png_mng_features flag from png_byte to png_uint_32.
+  Bumped shared-library (so-number) and dll-number to 3.
+
+Version 1.2.0beta4 [June 23, 2001]
+  Check for missing profile length field in iCCP chunk and free chunk_data
+    in case of truncated iCCP chunk.
+  Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
+  Bumped dll-number from 2 to 3 in makefile.cygwin
+  Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
+    if user attempts to run it on an 8-bit display.
+  Updated contrib/gregbook
+  Use png_malloc instead of png_zalloc to allocate palette in pngset.c
+  Updated makefile.ibmc
+  Added some typecasts to eliminate gcc 3.0 warnings.  Changed prototypes
+    of png_write_oFFS width and height from png_uint_32 to png_int_32.
+  Updated example.c
+  Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
+
+Version 1.2.0beta5 [August 8, 2001]
+  Revised contrib/gregbook
+  Revised makefile.gcmmx
+  Revised pnggccrd.c to conditionally compile some thread-unsafe code only
+    when PNG_THREAD_UNSAFE_OK is defined.
+  Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
+    value exceeding 2^bit_depth-1
+  Revised makefile.sgi and makefile.sggcc
+  Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
+  Removed restriction that do_invert_mono only operate on 1-bit opaque files
+
+Version 1.2.0 [September 1, 2001]
+  Changed a png_warning() to png_debug() in pnggccrd.c
+  Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC().
+
+Version 1.2.1beta1 [October 19, 2001]
+  Revised makefile.std in contrib/pngminus
+  Include background_1 in png_struct regardless of gamma support.
+  Revised makefile.netbsd and makefile.macosx, added makefile.darwin.
+  Revised example.c to provide more details about using row_callback().
+
+Version 1.2.1beta2 [October 25, 2001]
+  Added type cast to each NULL appearing in a function call, except for
+    WINCE functions.
+  Added makefile.so9.
+
+Version 1.2.1beta3 [October 27, 2001]
+  Removed type casts from all NULLs.
+  Simplified png_create_struct_2().
+
+Version 1.2.1beta4 [November 7, 2001]
+  Revised png_create_info_struct() and png_creat_struct_2().
+  Added error message if png_write_info() was omitted.
+  Type cast NULLs appearing in function calls when _NO_PROTO or
+    PNG_TYPECAST_NULL is defined.
+
+Version 1.2.1rc1 [November 24, 2001]
+  Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL
+    is defined.
+  Changed typecast of "size" argument to png_size_t in pngmem.c calls to
+    the user malloc_fn, to agree with the prototype in png.h
+  Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev)
+  Updated makefile.sgi to recognize LIBPATH and INCPATH.
+  Updated various makefiles so "make clean" does not remove previous major
+    version of the shared library.
+
+Version 1.2.1rc2 [December 4, 2001]
+  Always allocate 256-entry internal palette, hist, and trans arrays, to
+    avoid out-of-bounds memory reference caused by invalid PNG datastreams.
+  Added a check for prefix_length > data_length in iCCP chunk handler.
+
+Version 1.2.1 [December 7, 2001]
+  None.
+
+Version 1.2.2beta1 [February 22, 2002]
+  Fixed a bug with reading the length of iCCP profiles (Larry Reeves).
+  Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate
+    libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h
+  Revised makefile.darwin to remove "-undefined suppress" option.
+  Added checks for gamma and chromaticity values over 21474.83, which exceed
+    the limit for PNG unsigned 32-bit integers when encoded.
+  Revised calls to png_create_read_struct() and png_create_write_struct()
+    for simpler debugging.
+  Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK)
+
+Version 1.2.2beta2 [February 23, 2002]
+  Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths.
+  Check for invalid image dimensions in png_get_IHDR.
+  Added missing "fi;" in the install target of the SGI makefiles.
+  Added install-static to all makefiles that make shared libraries.
+  Always do gamma compensation when image is partially transparent.
+
+Version 1.2.2beta3 [March 7, 2002]
+  Compute background.gray and background_1.gray even when color_type is RGB
+    in case image gets reduced to gray later.
+  Modified shared-library makefiles to install pkgconfig/libpngNN.pc.
+  Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown
+  Removed unused png_write_destroy_info prototype from png.h
+  Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case
+  Added install-shared target to all makefiles that make shared libraries.
+  Stopped a double free of palette, hist, and trans when not using free_me.
+  Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64.
+
+Version 1.2.2beta4 [March 8, 2002]
+  Compute background.gray and background_1.gray even when color_type is RGB
+    in case image gets reduced to gray later (Jason Summers).
+  Relocated a misplaced /bin/rm in the "install-shared" makefile targets
+  Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library.
+
+Version 1.2.2beta5 [March 26, 2002]
+  Added missing PNGAPI to several function definitions.
+  Check for invalid bit_depth or color_type in png_get_IHDR(), and
+    check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen).
+  Revised iTXt support to accept NULL for lang and lang_key.
+  Compute gamma for color components of background even when color_type is gray.
+  Changed "()" to "{}" in scripts/libpng.pc.in.
+  Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN
+  Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so
+
+Version 1.2.2beta6 [March 31, 2002]
+
+Version 1.0.13beta1 [March 31, 2002]
+  Prevent png_zalloc() from trying to memset memory that it failed to acquire.
+  Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate).
+  Ensure that the right function (user or default) is used to free the
+    png_struct after an error in png_create_read_struct_2().
+
+Version 1.2.2rc1 [April 7, 2002]
+
+Version 1.0.13rc1 [April 7, 2002]
+  Save the ebx register in pnggccrd.c (Sami Farin)
+  Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner).
+  Updated makefiles to put headers in include/libpng and remove old include/*.h.
+
+Version 1.2.2 [April 15, 2002]
+
+Version 1.0.13 [April 15, 2002]
+  Revised description of png_set_filter() in libpng.3/libpng.txt.
+  Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd
+
+Version 1.0.13patch01 [April 17, 2002]
+
+Version 1.2.2patch01 [April 17, 2002]
+  Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and
+    makefile.sggcc
+  Fixed VER -> PNGVER typo in makefile.macosx and added install-static to
+    install
+  Added install: target to makefile.32sunu and makefile.64sunu
+
+Version 1.0.13patch03 [April 18, 2002]
+
+Version 1.2.2patch03 [April 18, 2002]
+  Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng
+  subdirectory to libpngNN subdirectory without the full pathname.
+  Moved generation of libpng.pc from "install" to "all" in 15 makefiles.
+
+Version 1.2.3rc1 [April 28, 2002]
+  Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos).
+  Added $(DESTDIR) feature to 24 makefiles (Tim Mooney)
+  Fixed bug with $prefix, should be $(prefix) in makefile.hpux.
+  Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin
+  Added a link from libpngNN.pc to libpng.pc in 15 makefiles.
+  Added links from include/libpngNN/*.h to include/*.h in 24 makefiles.
+  Revised makefile.darwin to make relative links without full pathname.
+  Added setjmp() at the end of png_create_*_struct_2() in case user forgets
+    to put one in their application.
+  Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and
+    removed them from module definition files.
+
+Version 1.2.3rc2 [May 1, 2002]
+  Fixed bug in reporting number of channels in pngget.c and pngset.c,
+    that was introduced in version 1.2.2beta5.
+  Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(),
+    png_default_flush(), and png_push_fill_buffer() and included them in
+    module definition files.
+  Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles.
+
+Version 1.2.3rc3 [May 1, 2002]
+  Revised prototype for png_default_flush()
+  Remove old libpng.pc and libpngNN.pc before installing new ones.
+
+Version 1.2.3rc4 [May 2, 2002]
+  Typos in *.def files (png_default_read|write -> png_default_read|write_data)
+  In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc
+  Added libpng-config and libpngNN-config and modified makefiles to install
+    them.
+  Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles
+  Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp
+
+Version 1.2.3rc5 [May 11, 2002]
+  Changed "error" and "message" in prototypes to "error_message" and
+    "warning_message" to avoid namespace conflict.
+  Revised 15 makefiles to build libpng-config from libpng-config-*.in
+  Once more restored png_zalloc and png_zfree to regular nonexported form.
+  Restored png_default_read|write_data, png_default_flush, png_read_fill_buffer
+    to nonexported form, but with PNGAPI, and removed them from module def
+    files.
+
+Version 1.2.3rc6 [May 14, 2002]
+  Removed "PNGAPI" from png_zalloc() and png_zfree() in png.c
+  Changed "Gz" to "Gd" in projects/msvc/libpng.dsp and zlib.dsp.
+  Removed leftover libpng-config "sed" script from four makefiles.
+  Revised libpng-config creating script in 16 makefiles.
+
+Version 1.2.3 [May 22, 2002]
+  Revised libpng-config target in makefile.cygwin.
+  Removed description of png_set_mem_fn() from documentation.
+  Revised makefile.freebsd.
+  Minor cosmetic changes to 15 makefiles, e.g., $(DI) = $(DESTDIR)/$(INCDIR).
+  Revised projects/msvc/README.txt
+  Changed -lpng to -lpngNN in LDFLAGS in several makefiles.
+
+Version 1.2.4beta1 [May 24, 2002]
+  Added libpng.pc and libpng-config to "all:" target in 16 makefiles.
+  Fixed bug in 16 makefiles: $(DESTDIR)/$(LIBPATH) to $(DESTDIR)$(LIBPATH)
+  Added missing "\" before closing double quote in makefile.gcmmx.
+  Plugged various memory leaks; added png_malloc_warn() and png_set_text_2()
+    functions.
+
+Version 1.2.4beta2 [June 25, 2002]
+  Plugged memory leak of png_ptr->current_text (Matt Holgate).
+  Check for buffer overflow before reading CRC in pngpread.c (Warwick Allison)
+  Added -soname to the loader flags in makefile.dec, makefile.sgi, and
+    makefile.sggcc.
+  Added "test-installed" target to makefile.linux, makefile.gcmmx,
+    makefile.sgi, and makefile.sggcc.
+
+Version 1.2.4beta3 [June 28, 2002]
+  Plugged memory leak of row_buf in pngtest.c when there is a png_error().
+  Detect buffer overflow in pngpread.c when IDAT is corrupted with extra data.
+  Added "test-installed" target to makefile.32sunu, makefile.64sunu,
+    makefile.beos, makefile.darwin, makefile.dec, makefile.macosx,
+    makefile.solaris, makefile.hpux, makefile.hpgcc, and makefile.so9.
+
+Version 1.2.4rc1 and 1.0.14rc1 [July 2, 2002]
+  Added "test-installed" target to makefile.cygwin and makefile.sco.
+  Revised pnggccrd.c to be able to back out version 1.0.x via PNG_1_0_X macro.
+
+Version 1.2.4 and 1.0.14 [July 8, 2002]
+  Changed png_warning() to png_error() when width is too large to process.
+
+Version 1.2.4patch01 [July 20, 2002]
+  Revised makefile.cygwin to use DLL number 12 instead of 13.
+
+Version 1.2.5beta1 [August 6, 2002]
+  Added code to contrib/gregbook/readpng2.c to ignore unused chunks.
+  Replaced toucan.png in contrib/gregbook (it has been corrupt since 1.0.11)
+  Removed some stray *.o files from contrib/gregbook.
+  Changed png_error() to png_warning() about "Too much data" in pngpread.c
+    and about "Extra compressed data" in pngrutil.c.
+  Prevent png_ptr->pass from exceeding 7 in png_push_finish_row().
+  Updated makefile.hpgcc
+  Updated png.c and pnggccrd.c handling of return from png_mmx_support()
+
+Version 1.2.5beta2 [August 15, 2002]
+  Only issue png_warning() about "Too much data" in pngpread.c when avail_in
+    is nonzero.
+  Updated makefiles to install a separate libpng.so.3 with its own rpath.
+
+Version 1.2.5rc1 and 1.0.15rc1 [August 24, 2002]
+  Revised makefiles to not remove previous minor versions of shared libraries.
+
+Version 1.2.5rc2 and 1.0.15rc2 [September 16, 2002]
+  Revised 13 makefiles to remove "-lz" and "-L$(ZLIBLIB)", etc., from shared
+    library loader directive.
+  Added missing "$OBJSDLL" line to makefile.gcmmx.
+  Added missing "; fi" to makefile.32sunu.
+
+Version 1.2.5rc3 and 1.0.15rc3 [September 18, 2002]
+  Revised libpng-config script.
+
+Version 1.2.5 and 1.0.15 [October 3, 2002]
+  Revised makefile.macosx, makefile.darwin, makefile.hpgcc, and makefile.hpux,
+    and makefile.aix.
+  Relocated two misplaced PNGAPI lines in pngtest.c
+
+Version 1.2.6beta1 [October 22, 2002]
+  Commented out warning about uninitialized mmx_support in pnggccrd.c.
+  Changed "IBMCPP__" flag to "__IBMCPP__" in pngconf.h.
+  Relocated two more misplaced PNGAPI lines in pngtest.c
+  Fixed memory overrun bug in png_do_read_filler() with 16-bit datastreams,
+    introduced in version 1.0.2.
+  Revised makefile.macosx, makefile.dec, makefile.aix, and makefile.32sunu.
+
+Version 1.2.6beta2 [November 1, 2002]
+  Added libpng-config "--ldopts" output.
+  Added "AR=ar" and "ARFLAGS=rc" and changed "ar rc" to "$(AR) $(ARFLAGS)"
+    in makefiles.
+
+Version 1.2.6beta3 [July 18, 2004]
+  Reverted makefile changes from version 1.2.6beta2 and some of the changes
+    from version 1.2.6beta1; these will be postponed until version 1.2.7.
+    Version 1.2.6 is going to be a simple bugfix release.
+  Changed the one instance of "ln -sf" to "ln -f -s" in each Sun makefile.
+  Fixed potential overrun in pngerror.c by using strncpy instead of memcpy.
+  Added "#!/bin/sh" at the top of configure, for recognition of the
+    'x' flag under Cygwin (Cosmin).
+  Optimized vacuous tests that silence compiler warnings, in png.c (Cosmin).
+  Added support for PNG_USER_CONFIG, in pngconf.h (Cosmin).
+  Fixed the special memory handler for Borland C under DOS, in pngmem.c
+    (Cosmin).
+  Removed some spurious assignments in pngrutil.c (Cosmin).
+  Replaced 65536 with 65536L, and 0xffff with 0xffffL, to silence warnings
+    on 16-bit platforms (Cosmin).
+  Enclosed shift op expressions in parentheses, to silence warnings (Cosmin).
+  Used proper type png_fixed_point, to avoid problems on 16-bit platforms,
+    in png_handle_sRGB() (Cosmin).
+  Added compression_type to png_struct, and optimized the window size
+    inside the deflate stream (Cosmin).
+  Fixed definition of isnonalpha(), in pngerror.c and pngrutil.c (Cosmin).
+  Fixed handling of unknown chunks that come after IDAT (Cosmin).
+  Allowed png_error() and png_warning() to work even if png_ptr == NULL
+    (Cosmin).
+  Replaced row_info->rowbytes with row_bytes in png_write_find_filter()
+    (Cosmin).
+  Fixed definition of PNG_LIBPNG_VER_DLLNUM (Simon-Pierre).
+  Used PNG_LIBPNG_VER and PNG_LIBPNG_VER_STRING instead of the hardcoded
+    values in png.c (Simon-Pierre, Cosmin).
+  Initialized png_libpng_ver[] with PNG_LIBPNG_VER_STRING (Simon-Pierre).
+  Replaced PNG_LIBPNG_VER_MAJOR with PNG_LIBPNG_VER_DLLNUM in png.rc
+    (Simon-Pierre).
+  Moved the definition of PNG_HEADER_VERSION_STRING near the definitions
+    of the other PNG_LIBPNG_VER_... symbols in png.h (Cosmin).
+  Relocated #ifndef PNGAPI guards in pngconf.h (Simon-Pierre, Cosmin).
+  Updated scripts/makefile.vc(a)win32 (Cosmin).
+  Updated the MSVC project (Simon-Pierre, Cosmin).
+  Updated the Borland C++ Builder project (Cosmin).
+  Avoided access to asm_flags in pngvcrd.c, if PNG_1_0_X is defined (Cosmin).
+  Commented out warning about uninitialized mmx_support in pngvcrd.c (Cosmin).
+  Removed scripts/makefile.bd32 and scripts/pngdef.pas (Cosmin).
+  Added extra guard around inclusion of Turbo C memory headers, in pngconf.h
+    (Cosmin).
+  Renamed projects/msvc/ to projects/visualc6/, and projects/borland/ to
+    projects/cbuilder5/ (Cosmin).
+  Moved projects/visualc6/png32ms.def to scripts/pngw32.def,
+    and projects/visualc6/png.rc to scripts/pngw32.rc (Cosmin).
+  Added projects/visualc6/pngtest.dsp; removed contrib/msvctest/ (Cosmin).
+  Changed line endings to DOS style in cbuilder5 and visualc6 files, even
+    in the tar.* distributions (Cosmin).
+  Updated contrib/visupng/VisualPng.dsp (Cosmin).
+  Updated contrib/visupng/cexcept.h to version 2.0.0 (Cosmin).
+  Added a separate distribution with "configure" and supporting files (Junichi).
+
+Version 1.2.6beta4 [July 28, 2004]
+  Added user ability to change png_size_t via a PNG_SIZE_T macro.
+  Added png_sizeof() and png_convert_size() functions.
+  Added PNG_SIZE_MAX (maximum value of a png_size_t variable.
+  Added check in png_malloc_default() for (size_t)size != (png_uint_32)size
+    which would indicate an overflow.
+  Changed sPLT failure action from png_error to png_warning and abandon chunk.
+  Changed sCAL and iCCP failures from png_error to png_warning and abandon.
+  Added png_get_uint_31(png_ptr, buf) function.
+  Added PNG_UINT_32_MAX macro.
+  Renamed PNG_MAX_UINT to PNG_UINT_31_MAX.
+  Made png_zalloc() issue a png_warning and return NULL on potential
+    overflow.
+  Turn on PNG_NO_ZALLOC_ZERO by default in version 1.2.x
+  Revised "clobber list" in pnggccrd.c so it will compile under gcc-3.4.
+  Revised Borland portion of png_malloc() to return NULL or issue
+    png_error() according to setting of PNG_FLAG_MALLOC_NULL_MEM_OK.
+  Added PNG_NO_SEQUENTIAL_READ_SUPPORTED macro to conditionally remove
+    sequential read support.
+  Added some "#if PNG_WRITE_SUPPORTED" blocks.
+  Added #ifdef to remove some redundancy in png_malloc_default().
+  Use png_malloc instead of png_zalloc to allocate the palette.
+
+Version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
+  Fixed buffer overflow vulnerability (CVE-2004-0597) in png_handle_tRNS().
+  Fixed NULL dereference vulnerability (CVE-2004-0598) in png_handle_iCCP().
+  Fixed integer overflow vulnerability (CVE-2004-0599) in png_read_png().
+  Fixed some harmless bugs in png_handle_sBIT, etc, that would cause
+    duplicate chunk types to go undetected.
+  Fixed some timestamps in the -config version
+  Rearranged order of processing of color types in png_handle_tRNS().
+  Added ROWBYTES macro to calculate rowbytes without integer overflow.
+  Updated makefile.darwin and removed makefile.macosx from scripts directory.
+  Imposed default one million column, one-million row limits on the image
+    dimensions, and added png_set_user_limits() function to override them.
+  Revised use of PNG_SET_USER_LIMITS_SUPPORTED macro.
+  Fixed wrong cast of returns from png_get_user_width|height_max().
+  Changed some "keep the compiler happy" from empty statements to returns,
+  Revised libpng.txt to remove 1.2.x stuff from the 1.0.x distribution
+
+Version 1.0.16rc2 and 1.2.6rc2 [August 7, 2004]
+  Revised makefile.darwin and makefile.solaris.  Removed makefile.macosx.
+  Revised pngtest's png_debug_malloc() to use png_malloc() instead of
+    png_malloc_default() which is not supposed to be exported.
+  Fixed off-by-one error in one of the conversions to PNG_ROWBYTES() in
+    pngpread.c.  Bug was introduced in 1.2.6rc1.
+  Fixed bug in RGB to RGBX transformation introduced in 1.2.6rc1.
+  Fixed old bug in RGB to Gray transformation.
+  Fixed problem with 64-bit compilers by casting arguments to abs()
+    to png_int_32.
+  Changed "ln -sf" to "ln -f -s" in three makefiles (solaris, sco, so9).
+  Changed "HANDLE_CHUNK_*" to "PNG_HANDLE_CHUNK_*" (Cosmin)
+  Added "-@/bin/rm -f $(DL)/$(LIBNAME).so.$(PNGMAJ)" to 15 *NIX makefiles.
+  Added code to update the row_info->colortype in png_do_read_filler() (MSB).
+
+Version 1.0.16rc3 and 1.2.6rc3 [August 9, 2004]
+  Eliminated use of "abs()" in testing cHRM and gAMA values, to avoid
+    trouble with some 64-bit compilers.  Created PNG_OUT_OF_RANGE() macro.
+  Revised documentation of png_set_keep_unknown_chunks().
+  Check handle_as_unknown status in pngpread.c, as in pngread.c previously.
+  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_INTERNAL section of png.h
+  Added "rim" definitions for CONST4 and CONST6 in pnggccrd.c
+
+Version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004]
+  Fixed mistake in pngtest.c introduced in 1.2.6rc2 (declaration of
+    "pinfo" was out of place).
+
+Version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004]
+  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED
+    section of png.h where they were inadvertently placed in version rc3.
+
+Version 1.2.6 and 1.0.16 [August 15, 2004]
+  Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1.
+
+Version 1.2.7beta1 [August 26, 2004]
+  Removed unused pngasmrd.h file.
+  Removed references to uu.net for archived files.  Added references to
+    PNG Spec (second edition) and the PNG ISO/IEC Standard.
+  Added "test-dd" target in 15 makefiles, to run pngtest in DESTDIR.
+  Fixed bug with "optimized window size" in the IDAT datastream, that
+    causes libpng to write PNG files with incorrect zlib header bytes.
+
+Version 1.2.7beta2 [August 28, 2004]
+  Fixed bug with sCAL chunk and big-endian machines (David Munro).
+  Undid new code added in 1.2.6rc2 to update the color_type in
+    png_set_filler().
+  Added png_set_add_alpha() that updates color type.
+
+Version 1.0.17rc1 and 1.2.7rc1 [September 4, 2004]
+  Revised png_set_strip_filler() to not remove alpha if color_type has alpha.
+
+Version 1.2.7 and 1.0.17 [September 12, 2004]
+  Added makefile.hp64
+  Changed projects/msvc/png32ms.def to scripts/png32ms.def in makefile.cygwin
+
+Version 1.2.8beta1 [November 1, 2004]
+  Fixed bug in png_text_compress() that would fail to complete a large block.
+  Fixed bug, introduced in libpng-1.2.7, that overruns a buffer during
+    strip alpha operation in png_do_strip_filler().
+  Added PNG_1_2_X definition in pngconf.h
+  Use #ifdef to comment out png_info_init in png.c and png_read_init in
+    pngread.c (as of 1.3.0)
+
+Version 1.2.8beta2 [November 2, 2004]
+  Reduce color_type to a nonalpha type after strip alpha operation in
+    png_do_strip_filler().
+
+Version 1.2.8beta3 [November 3, 2004]
+  Revised definitions of PNG_MAX_UINT_32, PNG_MAX_SIZE, and PNG_MAXSUM
+
+Version 1.2.8beta4 [November 12, 2004]
+  Fixed (again) definition of PNG_LIBPNG_VER_DLLNUM in png.h (Cosmin).
+  Added PNG_LIBPNG_BUILD_PRIVATE in png.h (Cosmin).
+  Set png_ptr->zstream.data_type to Z_BINARY, to avoid unnecessary detection
+    of data type in deflate (Cosmin).
+  Deprecated but continue to support SPECIALBUILD and PRIVATEBUILD in favor of
+    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
+
+Version 1.2.8beta5 [November 20, 2004]
+  Use png_ptr->flags instead of png_ptr->transformations to pass
+    PNG_STRIP_ALPHA info to png_do_strip_filler(), to preserve ABI
+    compatibility.
+  Revised handling of SPECIALBUILD, PRIVATEBUILD,
+    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
+
+Version 1.2.8rc1 [November 24, 2004]
+  Moved handling of BUILD macros from pngconf.h to png.h
+  Added definition of PNG_LIBPNG_BASE_TYPE in png.h, inadvertently
+    omitted from beta5.
+  Revised scripts/pngw32.rc
+  Despammed mailing addresses by masking "@" with "at".
+  Inadvertently installed a supposedly faster test version of pngrutil.c
+
+Version 1.2.8rc2 [November 26, 2004]
+  Added two missing "\" in png.h
+  Change tests in pngread.c and pngpread.c to
+    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
+       png_do_read_transformations(png_ptr);
+
+Version 1.2.8rc3 [November 28, 2004]
+  Reverted pngrutil.c to version libpng-1.2.8beta5.
+  Added scripts/makefile.elf with supporting code in pngconf.h for symbol
+    versioning (John Bowler).
+
+Version 1.2.8rc4 [November 29, 2004]
+  Added projects/visualc7 (Simon-pierre).
+
+Version 1.2.8rc5 [November 29, 2004]
+  Fixed new typo in scripts/pngw32.rc
+
+Version 1.2.8 [December 3, 2004]
+  Removed projects/visualc7, added projects/visualc71.
+
+Version 1.2.9beta1 [February 21, 2006]
+  Initialized some structure members in pngwutil.c to avoid gcc-4.0.0 complaints
+  Revised man page and libpng.txt to make it clear that one should not call
+    png_read_end or png_write_end after png_read_png or png_write_png.
+  Updated references to png-mng-implement mailing list.
+  Fixed an incorrect typecast in pngrutil.c
+  Added PNG_NO_READ_SUPPORTED conditional for making a write-only library.
+  Added PNG_NO_WRITE_INTERLACING_SUPPORTED conditional.
+  Optimized alpha-inversion loops in pngwtran.c
+  Moved test for nonzero gamma outside of png_build_gamma_table() in pngrtran.c
+  Make sure num_trans is <= 256 before copying data in png_set_tRNS().
+  Make sure num_palette is <= 256 before copying data in png_set_PLTE().
+  Interchanged order of write_swap_alpha and write_invert_alpha transforms.
+  Added parentheses in the definition of PNG_LIBPNG_BUILD_TYPE (Cosmin).
+  Optimized zlib window flag (CINFO) in contrib/pngsuite/*.png (Cosmin).
+  Updated scripts/makefile.bc32 for Borland C++ 5.6 (Cosmin).
+  Exported png_get_uint_32, png_save_uint_32, png_get_uint_16, png_save_uint_16,
+    png_get_int_32, png_save_int_32, png_get_uint_31 (Cosmin).
+  Added type cast (png_byte) in png_write_sCAL() (Cosmin).
+  Fixed scripts/makefile.cygwin (Christian Biesinger, Cosmin).
+  Default iTXt support was inadvertently enabled.
+
+Version 1.2.9beta2 [February 21, 2006]
+  Check for png_rgb_to_gray and png_gray_to_rgb read transformations before
+    checking for png_read_dither in pngrtran.c
+  Revised checking of chromaticity limits to accommodate extended RGB
+    colorspace (John Denker).
+  Changed line endings in some of the project files to CRLF, even in the
+    "Unix" tar distributions (Cosmin).
+  Made png_get_int_32 and png_save_int_32 always available (Cosmin).
+  Updated scripts/pngos2.def, scripts/pngw32.def and projects/wince/png32ce.def
+    with the newly exported functions.
+  Eliminated distributions without the "configure" script.
+  Updated INSTALL instructions.
+
+Version 1.2.9beta3 [February 24, 2006]
+  Fixed CRCRLF line endings in contrib/visupng/VisualPng.dsp
+  Made libpng.pc respect EXEC_PREFIX (D. P. Kreil, J. Bowler)
+  Removed reference to pngasmrd.h from Makefile.am
+  Renamed CHANGES to ChangeLog.
+  Renamed LICENSE to COPYING.
+  Renamed ANNOUNCE to NEWS.
+  Created AUTHORS file.
+
+Version 1.2.9beta4 [March 3, 2006]
+  Changed definition of PKGCONFIG from $prefix/lib to $libdir in configure.ac
+  Reverted to filenames LICENSE and ANNOUNCE; removed AUTHORS and COPYING.
+  Removed newline from the end of some error and warning messages.
+  Removed test for sqrt() from configure.ac and configure.
+  Made swap tables in pngtrans.c PNG_CONST (Carlo Bramix).
+  Disabled default iTXt support that was inadvertently enabled in
+    libpng-1.2.9beta1.
+  Added "OS2" to list of systems that don't need underscores, in pnggccrd.c
+  Removed libpng version and date from *.c files.
+
+Version 1.2.9beta5 [March 4, 2006]
+  Removed trailing blanks from source files.
+  Put version and date of latest change in each source file, and changed
+    copyright year accordingly.
+  More cleanup of configure.ac, Makefile.am, and associated scripts.
+  Restored scripts/makefile.elf which was inadvertently deleted.
+
+Version 1.2.9beta6 [March 6, 2006]
+  Fixed typo (RELEASE) in configuration files.
+
+Version 1.2.9beta7 [March 7, 2006]
+  Removed libpng.vers and libpng.sym from libpng12_la_SOURCES in Makefile.am
+  Fixed inconsistent #ifdef's around png_sig_bytes() and png_set_sCAL_s()
+    in png.h.
+  Updated makefile.elf as suggested by debian.
+  Made cosmetic changes to some makefiles, adding LN_SF and other macros.
+  Made some makefiles accept "exec_prefix".
+
+Version 1.2.9beta8 [March 9, 2006]
+  Fixed some "#if defined (..." which should be "#if defined(..."
+    Bug introduced in libpng-1.2.8.
+  Fixed inconsistency in definition of png_default_read_data()
+  Restored blank that was lost from makefile.sggcc "clean" target in beta7.
+  Revised calculation of "current" and "major" for irix in ltmain.sh
+  Changed "mkdir" to "MKDIR_P" in some makefiles.
+  Separated PNG_EXPAND and PNG_EXPAND_tRNS.
+  Added png_set_expand_gray_1_2_4_to_8() and deprecated
+    png_set_gray_1_2_4_to_8() which also expands tRNS to alpha.
+
+Version 1.2.9beta9 [March 10, 2006]
+  Include "config.h" in pngconf.h when available.
+  Added some checks for NULL png_ptr or NULL info_ptr (timeless)
+
+Version 1.2.9beta10 [March 20, 2006]
+  Removed extra CR from contrib/visualpng/VisualPng.dsw (Cosmin)
+  Made pnggccrd.c PIC-compliant (Christian Aichinger).
+  Added makefile.mingw (Wolfgang Glas).
+  Revised pngconf.h MMX checking.
+
+Version 1.2.9beta11 [March 22, 2006]
+  Fixed out-of-order declaration in pngwrite.c that was introduced in beta9
+  Simplified some makefiles by using LIBSO, LIBSOMAJ, and LIBSOVER macros.
+
+Version 1.2.9rc1 [March 31, 2006]
+  Defined PNG_USER_PRIVATEBUILD when including "pngusr.h" (Cosmin).
+  Removed nonsensical assertion check from pngtest.c (Cosmin).
+
+Version 1.2.9 [April 14, 2006]
+  Revised makefile.beos and added "none" selector in ltmain.sh
+
+Version 1.2.10beta1 [April 15, 2006]
+  Renamed "config.h" to "png_conf.h" and revised Makefile.am to add
+    -DPNG_BUILDING_LIBPNG to compile directive, and modified pngconf.h
+    to include png_conf.h only when PNG_BUILDING_LIBPNG is defined.
+
+Version 1.2.10beta2 [April 15, 2006]
+  Manually updated Makefile.in and configure.  Changed png_conf.h.in
+    back to config.h.
+
+Version 1.2.10beta3 [April 15, 2006]
+  Change png_conf.h back to config.h in pngconf.h.
+
+Version 1.2.10beta4 [April 16, 2006]
+  Change PNG_BUILDING_LIBPNG to PNG_CONFIGURE_LIBPNG in config/Makefile*.
+
+Version 1.2.10beta5 [April 16, 2006]
+  Added a configure check for compiling assembler code in pnggccrd.c
+
+Version 1.2.10beta6 [April 17, 2006]
+  Revised the configure check for pnggccrd.c
+  Moved -DPNG_CONFIGURE_LIBPNG into @LIBPNG_DEFINES@
+  Added @LIBPNG_DEFINES@ to arguments when building libpng.sym
+
+Version 1.2.10beta7 [April 18, 2006]
+  Change "exec_prefix=$prefix" to "exec_prefix=$(prefix)" in makefiles.
+
+Version 1.2.10rc1 [April 19, 2006]
+  Ensure pngconf.h doesn't define both PNG_USE_PNGGCCRD and PNG_USE_PNGVCRD
+  Fixed "LN_FS" typo in makefile.sco and makefile.solaris.
+
+Version 1.2.10rc2 [April 20, 2006]
+  Added a backslash between -DPNG_CONFIGURE_LIBPNG and -DPNG_NO_ASSEMBLER_CODE
+   in configure.ac and configure
+  Made the configure warning about versioned symbols less arrogant.
+
+Version 1.2.10rc3 [April 21, 2006]
+  Added a note in libpng.txt that png_set_sig_bytes(8) can be used when
+    writing an embedded PNG without the 8-byte signature.
+  Revised makefiles and configure to avoid making links to libpng.so.*
+
+Version 1.2.10 [April 23, 2006]
+  Reverted configure to "rc2" state.
+
+Version 1.2.11beta1 [May 31, 2006]
+  scripts/libpng.pc.in contained "configure" style version info and would
+    not work with makefiles.
+  The shared-library makefiles were linking to libpng.so.0 instead of
+    libpng.so.3 compatibility as the library.
+
+Version 1.2.11beta2 [June 2, 2006]
+  Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+    buffer overflow.
+  Fixed bug in example.c (png_set_palette_rgb -> png_set_palette_to_rgb)
+
+Version 1.2.11beta3 [June 5, 2006]
+  Prepended "#! /bin/sh" to ltmail.sh and contrib/pngminus/*.sh (Cosmin).
+  Removed the accidental leftover Makefile.in~ (Cosmin).
+  Avoided potential buffer overflow and optimized buffer in
+    png_write_sCAL(), png_write_sCAL_s() (Cosmin).
+  Removed the include directories and libraries from CFLAGS and LDFLAGS
+    in scripts/makefile.gcc (Nelson A. de Oliveira, Cosmin).
+
+Version 1.2.11beta4 [June 6, 2006]
+  Allow zero-length IDAT chunks after the entire zlib datastream, but not
+    after another intervening chunk type.
+
+Version 1.0.19rc1, 1.2.11rc1 [June 13, 2006]
+  Deleted extraneous square brackets from [config.h] in configure.ac
+
+Version 1.0.19rc2, 1.2.11rc2 [June 14, 2006]
+  Added prototypes for PNG_INCH_CONVERSIONS functions to png.h
+  Revised INSTALL and autogen.sh
+  Fixed typo in several makefiles (-W1 should be -Wl)
+  Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
+
+Version 1.0.19rc3, 1.2.11rc3 [June 15, 2006]
+  Removed the new typedefs for 64-bit systems (delay until version 1.4.0)
+  Added one zero element to png_gamma_shift[] array in pngrtran.c to avoid
+    reading out of bounds.
+
+Version 1.0.19rc4, 1.2.11rc4 [June 15, 2006]
+  Really removed the new typedefs for 64-bit systems.
+
+Version 1.0.19rc5, 1.2.11rc5 [June 22, 2006]
+  Removed png_sig_bytes entry from scripts/pngw32.def
+
+Version 1.0.19, 1.2.11 [June 26, 2006]
+  None.
+
+Version 1.0.20, 1.2.12 [June 27, 2006]
+  Really increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+    buffer overflow.
+
+Version 1.2.13beta1 [October 2, 2006]
+  Removed AC_FUNC_MALLOC from configure.ac
+  Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
+  Change "logical" to "bitwise" throughout documentation.
+  Detect and fix attempt to write wrong iCCP profile length (CVE-2006-7244)
+
+Version 1.0.21, 1.2.13 [November 14, 2006]
+  Fix potential buffer overflow in sPLT chunk handler.
+  Fix Makefile.am to not try to link to noexistent files.
+  Check all exported functions for NULL png_ptr.
+
+Version 1.2.14beta1 [November 17, 2006]
+  Relocated three misplaced tests for NULL png_ptr.
+  Built Makefile.in with automake-1.9.6 instead of 1.9.2.
+  Build configure with autoconf-2.60 instead of 2.59
+
+Version 1.2.14beta2 [November 17, 2006]
+  Added some typecasts in png_zalloc().
+
+Version 1.2.14rc1 [November 20, 2006]
+  Changed "strtod" to "png_strtod" in pngrutil.c
+
+Version 1.0.22, 1.2.14    [November 27, 2006]
+  Added missing "$(srcdir)" in Makefile.am and Makefile.in
+
+Version 1.2.15beta1 [December 3, 2006]
+  Generated configure with autoconf-2.61 instead of 2.60
+  Revised configure.ac to update libpng.pc and libpng-config.
+
+Version 1.2.15beta2 [December 3, 2006]
+  Always export MMX asm functions, just stubs if not building pnggccrd.c
+
+Version 1.2.15beta3 [December 4, 2006]
+  Add "png_bytep" typecast to profile while calculating length in pngwutil.c
+
+Version 1.2.15beta4 [December 7, 2006]
+  Added scripts/CMakeLists.txt
+  Changed PNG_NO_ASSEMBLER_CODE to PNG_NO_MMX_CODE in scripts, like 1.4.0beta
+
+Version 1.2.15beta5 [December 7, 2006]
+  Changed some instances of PNG_ASSEMBLER_* to PNG_MMX_* in pnggccrd.c
+  Revised scripts/CMakeLists.txt
+
+Version 1.2.15beta6 [December 13, 2006]
+  Revised scripts/CMakeLists.txt and configure.ac
+
+Version 1.2.15rc1 [December 18, 2006]
+  Revised scripts/CMakeLists.txt
+
+Version 1.2.15rc2 [December 21, 2006]
+  Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
+  Added scripts/makefile.nommx
+
+Version 1.2.15rc3 [December 25, 2006]
+  Fixed shared library numbering error that was introduced in 1.2.15beta6.
+
+Version 1.2.15rc4 [December 27, 2006]
+  Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set.
+
+Version 1.2.15rc5 [December 31, 2006]
+  Revised handling of rgb_to_gray.
+
+Version 1.2.15 [January 5, 2007]
+  Added some (unsigned long) typecasts in pngtest.c to avoid printing errors.
+
+Version 1.2.16beta1 [January 6, 2007]
+  Fix bugs in makefile.nommx
+
+Version 1.2.16beta2 [January 16, 2007]
+  Revised scripts/CMakeLists.txt
+
+Version 1.2.16 [January 31, 2007]
+  No changes.
+
+Version 1.2.17beta1 [March 6, 2007]
+  Revised scripts/CMakeLists.txt to install both shared and static libraries.
+  Deleted a redundant line from pngset.c.
+
+Version 1.2.17beta2 [April 26, 2007]
+  Relocated misplaced test for png_ptr == NULL in pngpread.c
+  Change "==" to "&" for testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN
+    flags.
+  Changed remaining instances of PNG_ASSEMBLER_* to PNG_MMX_*
+  Added pngerror() when write_IHDR fails in deflateInit2().
+  Added "const" to some array declarations.
+  Mention examples of libpng usage in the libpng*.txt and libpng.3 documents.
+
+Version 1.2.17rc1 [May 4, 2007]
+  No changes.
+
+Version 1.2.17rc2 [May 8, 2007]
+  Moved several PNG_HAVE_* macros out of PNG_INTERNAL because applications
+    calling set_unknown_chunk_location() need them.
+  Changed transformation flag from PNG_EXPAND_tRNS to PNG_EXPAND in
+    png_set_expand_gray_1_2_4_to_8().
+  Added png_ptr->unknown_chunk to hold working unknown chunk data, so it
+    can be free'ed in case of error.  Revised unknown chunk handling in
+    pngrutil.c and pngpread.c to use this structure.
+
+Version 1.2.17rc3 [May 8, 2007]
+  Revised symbol-handling in configure script.
+
+Version 1.2.17rc4 [May 10, 2007]
+  Revised unknown chunk handling to avoid storing unknown critical chunks.
+
+Version 1.0.25 [May 15, 2007]
+Version 1.2.17 [May 15, 2007]
+  Added "png_ptr->num_trans=0" before error return in png_handle_tRNS,
+    to eliminate a vulnerability (CVE-2007-2445, CERT VU#684664)
+
+Version 1.0.26 [May 15, 2007]
+Version 1.2.18 [May 15, 2007]
+  Reverted the libpng-1.2.17rc3 change to symbol-handling in configure script
+
+Version 1.2.19beta1 [May 18, 2007]
+  Changed "const static" to "static PNG_CONST" everywhere, mostly undoing
+    change of libpng-1.2.17beta2.  Changed other "const" to "PNG_CONST"
+  Changed some handling of unused parameters, to avoid compiler warnings.
+    "if (unused == NULL) return;" becomes "unused = unused".
+
+Version 1.2.19beta2 [May 18, 2007]
+  Only use the valid bits of tRNS value in png_do_expand() (Brian Cartier)
+
+Version 1.2.19beta3 [May 19, 2007]
+  Add some "png_byte" typecasts in png_check_keyword() and write new_key
+  instead of key in zTXt chunk (Kevin Ryde).
+
+Version 1.2.19beta4 [May 21, 2007]
+  Add png_snprintf() function and use it in place of sprint() for improved
+    defense against buffer overflows.
+
+Version 1.2.19beta5 [May 21, 2007]
+  Fixed png_handle_tRNS() to only use the valid bits of tRNS value.
+  Changed handling of more unused parameters, to avoid compiler warnings.
+  Removed some PNG_CONST in pngwutil.c to avoid compiler warnings.
+
+Version 1.2.19beta6 [May 22, 2007]
+  Added some #ifdef PNG_MMX_CODE_SUPPORTED where needed in pngvcrd.c
+  Added a special "_MSC_VER" case that defines png_snprintf to _snprintf
+
+Version 1.2.19beta7 [May 22, 2007]
+  Squelched png_squelch_warnings() in pnggccrd.c and added
+    an #ifdef PNG_MMX_CODE_SUPPORTED block around the declarations that caused
+    the warnings that png_squelch_warnings was squelching.
+
+Version 1.2.19beta8 [May 22, 2007]
+  Removed __MMX__ from test in pngconf.h.
+
+Version 1.2.19beta9 [May 23, 2007]
+  Made png_squelch_warnings() available via PNG_SQUELCH_WARNINGS macro.
+  Revised png_squelch_warnings() so it might work.
+  Updated makefile.sgcc and makefile.solaris; added makefile.solaris-x86.
+
+Version 1.2.19beta10 [May 24, 2007]
+  Resquelched png_squelch_warnings(), use "__attribute__((used))" instead.
+
+Version 1.4.0beta1 [April 20, 2006]
+  Enabled iTXt support (changes png_struct, thus requires so-number change).
+  Cleaned up PNG_ASSEMBLER_CODE_SUPPORTED vs PNG_MMX_CODE_SUPPORTED
+  Eliminated PNG_1_0_X and PNG_1_2_X macros.
+  Removed deprecated functions png_read_init, png_write_init, png_info_init,
+    png_permit_empty_plte, png_set_gray_1_2_4_to_8, png_check_sig, and
+    removed the deprecated macro PNG_MAX_UINT.
+  Moved "PNG_INTERNAL" parts of png.h and pngconf.h into pngintrn.h
+  Removed many WIN32_WCE #ifdefs (Cosmin).
+  Reduced dependency on C-runtime library when on Windows (Simon-Pierre)
+  Replaced sprintf() with png_sprintf() (Simon-Pierre)
+
+Version 1.4.0beta2 [April 20, 2006]
+  Revised makefiles and configure to avoid making links to libpng.so.*
+  Moved some leftover MMX-related defines from pngconf.h to pngintrn.h
+  Updated scripts/pngos2.def, pngw32.def, and projects/wince/png32ce.def
+
+Version 1.4.0beta3 [May 10, 2006]
+  Updated scripts/pngw32.def to comment out MMX functions.
+  Added PNG_NO_GET_INT_32 and PNG_NO_SAVE_INT_32 macros.
+  Scripts/libpng.pc.in contained "configure" style version info and would
+    not work with makefiles.
+  Revised pngconf.h and added pngconf.h.in, so makefiles and configure can
+    pass defines to libpng and applications.
+
+Version 1.4.0beta4 [May 11, 2006]
+  Revised configure.ac, Makefile.am, and many of the makefiles to write
+    their defines in pngconf.h.
+
+Version 1.4.0beta5 [May 15, 2006]
+  Added a missing semicolon in Makefile.am and Makefile.in
+  Deleted extraneous square brackets from configure.ac
+
+Version 1.4.0beta6 [June 2, 2006]
+  Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+    buffer overflow.
+  Changed sonum from 0 to 1.
+  Removed unused prototype for png_check_sig() from png.h
+
+Version 1.4.0beta7 [June 16, 2006]
+  Exported png_write_sig (Cosmin).
+  Optimized buffer in png_handle_cHRM() (Cosmin).
+  Set pHYs = 2835 x 2835 pixels per meter, and added
+    sCAL = 0.352778e-3 x 0.352778e-3 meters, in pngtest.png (Cosmin).
+  Added png_set_benign_errors(), png_benign_error(), png_chunk_benign_error().
+  Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
+  Added "(unsigned long)" typecast on png_uint_32 variables in printf lists.
+
+Version 1.4.0beta8 [June 22, 2006]
+  Added demonstration of user chunk support in pngtest.c, to support the
+    public sTER chunk and a private vpAg chunk.
+
+Version 1.4.0beta9 [July 3, 2006]
+  Removed ordinals from scripts/pngw32.def and removed png_info_int and
+    png_set_gray_1_2_4_to_8 entries.
+  Inline call of png_get_uint_32() in png_get_uint_31().
+  Use png_get_uint_31() to get vpAg width and height in pngtest.c
+  Removed WINCE and Netware projects.
+  Removed standalone Y2KINFO file.
+
+Version 1.4.0beta10 [July 12, 2006]
+  Eliminated automatic copy of pngconf.h to pngconf.h.in from configure and
+    some makefiles, because it was not working reliably.  Instead, distribute
+    pngconf.h.in along with pngconf.h and cause configure and some of the
+    makefiles to update pngconf.h from pngconf.h.in.
+  Added pngconf.h to DEPENDENCIES in Makefile.am
+
+Version 1.4.0beta11 [August 19, 2006]
+  Removed AC_FUNC_MALLOC from configure.ac.
+  Added a warning when writing iCCP profile with mismatched profile length.
+  Patched pnggccrd.c to assemble on x86_64 platforms.
+  Moved chunk header reading into a separate function png_read_chunk_header()
+    in pngrutil.c.  The chunk header (len+sig) is now serialized in a single
+    operation (Cosmin).
+  Implemented support for I/O states. Added png_ptr member io_state, and
+    functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+    (Cosmin).
+  Added png_get_io_chunk_name and png_get_io_state to scripts/*.def (Cosmin).
+  Renamed scripts/pngw32.* to scripts/pngwin.* (Cosmin).
+  Removed the include directories and libraries from CFLAGS and LDFLAGS
+    in scripts/makefile.gcc (Cosmin).
+  Used png_save_uint_32() to set vpAg width and height in pngtest.c (Cosmin).
+  Cast to proper type when getting/setting vpAg units in pngtest.c (Cosmin).
+  Added pngintrn.h to the Visual C++ projects (Cosmin).
+  Removed scripts/list (Cosmin).
+  Updated copyright year in scripts/pngwin.def (Cosmin).
+  Removed PNG_TYPECAST_NULL and used standard NULL consistently (Cosmin).
+  Disallowed the user to redefine png_size_t, and enforced a consistent use
+    of png_size_t across libpng (Cosmin).
+  Changed the type of png_ptr->rowbytes, PNG_ROWBYTES() and friends
+    to png_size_t (Cosmin).
+  Removed png_convert_size() and replaced png_sizeof with sizeof (Cosmin).
+  Removed some unnecessary type casts (Cosmin).
+  Changed prototype of png_get_compression_buffer_size() and
+    png_set_compression_buffer_size() to work with png_size_t instead of
+    png_uint_32 (Cosmin).
+  Removed png_memcpy_check() and png_memset_check() (Cosmin).
+  Fixed a typo (png_byte --> png_bytep) in libpng.3 and libpng.txt (Cosmin).
+  Clarified that png_zalloc() does not clear the allocated memory,
+    and png_zalloc() and png_zfree() cannot be PNGAPI (Cosmin).
+  Renamed png_mem_size_t to png_alloc_size_t, fixed its definition in
+    pngconf.h, and used it in all memory allocation functions (Cosmin).
+  Renamed pngintrn.h to pngpriv.h, added a comment at the top of the file
+    mentioning that the symbols declared in that file are private, and
+    updated the scripts and the Visual C++ projects accordingly (Cosmin).
+  Removed circular references between pngconf.h and pngconf.h.in in
+    scripts/makefile.vc*win32 (Cosmin).
+  Removing trailing '.' from the warning and error messages (Cosmin).
+  Added pngdefs.h that is built by makefile or configure, instead of
+    pngconf.h.in (Glenn).
+  Detect and fix attempt to write wrong iCCP profile length.
+
+Version 1.4.0beta12 [October 19, 2006]
+  Changed "logical" to "bitwise" in the documentation.
+  Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
+  Add a typecast to stifle compiler warning in pngrutil.c
+
+Version 1.4.0beta13 [November 10, 2006]
+  Fix potential buffer overflow in sPLT chunk handler.
+  Fix Makefile.am to not try to link to noexistent files.
+
+Version 1.4.0beta14 [November 15, 2006]
+  Check all exported functions for NULL png_ptr.
+
+Version 1.4.0beta15 [November 17, 2006]
+  Relocated two misplaced tests for NULL png_ptr.
+  Built Makefile.in with automake-1.9.6 instead of 1.9.2.
+  Build configure with autoconf-2.60 instead of 2.59
+  Add "install: all" in Makefile.am so "configure; make install" will work.
+
+Version 1.4.0beta16 [November 17, 2006]
+  Added a typecast in png_zalloc().
+
+Version 1.4.0beta17 [December 4, 2006]
+  Changed "new_key[79] = '\0';" to "(*new_key)[79] = '\0';" in pngwutil.c
+  Add "png_bytep" typecast to profile while calculating length in pngwutil.c
+
+Version 1.4.0beta18 [December 7, 2006]
+  Added scripts/CMakeLists.txt
+
+Version 1.4.0beta19 [May 16, 2007]
+  Revised scripts/CMakeLists.txt
+  Rebuilt configure and Makefile.in with newer tools.
+  Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
+  Added scripts/makefile.nommx
+
+Version 1.4.0beta20 [July 9, 2008]
+  Moved several PNG_HAVE_* macros from pngpriv.h to png.h because applications
+    calling set_unknown_chunk_location() need them.
+  Moved several macro definitions from pngpriv.h to pngconf.h
+  Merge with changes to the 1.2.X branch, as of 1.2.30beta04.
+  Deleted all use of the MMX assembler code and Intel-licensed optimizations.
+  Revised makefile.mingw
+
+Version 1.4.0beta21 [July 21, 2008]
+  Moved local array "chunkdata" from pngrutil.c to the png_struct, so
+    it will be freed by png_read_destroy() in case of a read error (Kurt
+    Christensen).
+
+Version 1.4.0beta22 [July 21, 2008]
+  Change "purpose" and "buffer" to png_ptr->chunkdata to avoid memory leaking.
+
+Version 1.4.0beta23 [July 22, 2008]
+  Change "chunkdata = NULL" to "png_ptr->chunkdata = NULL" several places in
+    png_decompress_chunk().
+
+Version 1.4.0beta24 [July 25, 2008]
+  Change all remaining "chunkdata" to "png_ptr->chunkdata" in
+    png_decompress_chunk(), and remove "chunkdata" from parameter list.
+  Put a call to png_check_chunk_name() in png_read_chunk_header().
+  Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte.
+  Removed two calls to png_check_chunk_name() occurring later in the process.
+  Define PNG_NO_ERROR_NUMBERS by default in pngconf.h
+
+Version 1.4.0beta25 [July 30, 2008]
+  Added a call to png_check_chunk_name() in pngpread.c
+  Reverted png_check_chunk_name() to accept a name with a lowercase 3rd byte.
+  Added png_push_have_buffer() function to pngpread.c
+  Eliminated PNG_BIG_ENDIAN_SUPPORTED and associated png_get_* macros.
+  Made inline expansion of png_get_*() optional with PNG_USE_READ_MACROS.
+  Eliminated all PNG_USELESS_TESTS and PNG_CORRECT_PALETTE_SUPPORTED code.
+  Synced contrib directory and configure files with libpng-1.2.30beta06.
+  Eliminated no-longer-used pngdefs.h (but it's still built in the makefiles)
+  Relocated a misplaced "#endif /* PNG_NO_WRITE_FILTER */" in pngwutil.c
+
+Version 1.4.0beta26 [August 4, 2008]
+  Removed png_push_have_buffer() function in pngpread.c.  It increased the
+    compiled library size slightly.
+  Changed "-Wall" to "-W -Wall" in the CFLAGS in all makefiles (Cosmin Truta)
+  Declared png_ptr "volatile" in pngread.c and pngwrite.c to avoid warnings.
+  Updated contrib/visupng/cexcept.h to version 2.0.1
+  Added PNG_LITERAL_CHARACTER macros for #, [, and ].
+
+Version 1.4.0beta27 [August 5, 2008]
+  Revised usage of PNG_LITERAL_SHARP in pngerror.c.
+  Moved newline character from individual png_debug messages into the
+    png_debug macros.
+  Allow user to #define their own png_debug, png_debug1, and png_debug2.
+
+Version 1.4.0beta28 [August 5, 2008]
+  Revised usage of PNG_LITERAL_SHARP in pngerror.c.
+  Added PNG_STRING_NEWLINE macro
+
+Version 1.4.0beta29 [August 9, 2008]
+  Revised usage of PNG_STRING_NEWLINE to work on non-ISO compilers.
+  Added PNG_STRING_COPYRIGHT macro.
+  Added non-ISO versions of png_debug macros.
+
+Version 1.4.0beta30 [August 14, 2008]
+  Added premultiplied alpha feature (Volker Wiendl).
+
+Version 1.4.0beta31 [August 18, 2008]
+  Moved png_set_premultiply_alpha from pngtrans.c to pngrtran.c
+  Removed extra crc check at the end of png_handle_cHRM().  Bug introduced
+    in libpng-1.4.0beta20.
+
+Version 1.4.0beta32 [August 19, 2008]
+  Added PNG_WRITE_FLUSH_SUPPORTED block around new png_flush() call.
+  Revised PNG_NO_STDIO version of png_write_flush()
+
+Version 1.4.0beta33 [August 20, 2008]
+  Added png_get|set_chunk_cache_max() to limit the total number of sPLT,
+    text, and unknown chunks that can be stored.
+
+Version 1.4.0beta34 [September 6, 2008]
+  Shortened tIME_string to 29 bytes in pngtest.c
+  Fixed off-by-one error introduced in png_push_read_zTXt() function in
+    libpng-1.2.30beta04/pngpread.c (Harald van Dijk)
+
+Version 1.4.0beta35 [October 6, 2008]
+  Changed "trans_values" to "trans_color".
+  Changed so-number from 0 to 14.  Some OS do not like 0.
+  Revised makefile.darwin to fix shared library numbering.
+  Change png_set_gray_1_2_4_to_8() to png_set_expand_gray_1_2_4_to_8()
+    in example.c (debian bug report)
+
+Version 1.4.0beta36 [October 25, 2008]
+  Sync with tEXt vulnerability fix in libpng-1.2.33rc02.
+
+Version 1.4.0beta37 [November 13, 2008]
+  Added png_check_cHRM in png.c and moved checking from pngget.c, pngrutil.c,
+    and pngwrite.c
+
+Version 1.4.0beta38 [November 22, 2008]
+  Added check for zero-area RGB cHRM triangle in png_check_cHRM() and
+    png_check_cHRM_fixed().
+
+Version 1.4.0beta39 [November 23, 2008]
+  Revised png_warning() to write its message on standard output by default
+    when warning_fn is NULL.
+
+Version 1.4.0beta40 [November 24, 2008]
+  Eliminated png_check_cHRM().  Instead, always use png_check_cHRM_fixed().
+  In png_check_cHRM_fixed(), ensure white_y is > 0, and removed redundant
+    check for all-zero coordinates that is detected by the triangle check.
+
+Version 1.4.0beta41 [November 26, 2008]
+  Fixed string vs pointer-to-string error in png_check_keyword().
+  Rearranged test expressions in png_check_cHRM_fixed() to avoid internal
+    overflows.
+  Added PNG_NO_CHECK_cHRM conditional.
+
+Version 1.4.0beta42, 43 [December 1, 2008]
+  Merge png_debug with version 1.2.34beta04.
+
+Version 1.4.0beta44 [December 6, 2008]
+  Removed redundant check for key==NULL before calling png_check_keyword()
+    to ensure that new_key gets initialized and removed extra warning
+    (Merge with version 1.2.34beta05 -- Arvan Pritchard).
+
+Version 1.4.0beta45 [December 9, 2008]
+  In png_write_png(), respect the placement of the filler bytes in an earlier
+    call to png_set_filler() (Jim Barry).
+
+Version 1.4.0beta46 [December 10, 2008]
+  Undid previous change and added PNG_TRANSFORM_STRIP_FILLER_BEFORE and
+    PNG_TRANSFORM_STRIP_FILLER_AFTER conditionals and deprecated
+    PNG_TRANSFORM_STRIP_FILLER (Jim Barry).
+
+Version 1.4.0beta47 [December 15, 2008]
+  Support for dithering was disabled by default, because it has never
+    been well tested and doesn't work very well.  The code has not
+    been removed, however, and can be enabled by building libpng with
+    PNG_READ_DITHER_SUPPORTED defined.
+
+Version 1.4.0beta48 [February 14, 2009]
+  Added new exported function png_calloc().
+  Combined several instances of png_malloc(); png_memset() into png_calloc().
+  Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
+    but was never defined.
+
+Version 1.4.0beta49 [February 28, 2009]
+  Added png_fileno() macro to pngconf.h, used in pngwio.c
+  Corrected order of #ifdef's in png_debug definition in png.h
+  Fixed bug introduced in libpng-1.4.0beta48 with the memset arguments
+    for pcal_params.
+  Fixed order of #ifdef directives in the png_debug defines in png.h
+    (bug introduced in libpng-1.2.34/1.4.0beta29).
+  Revised comments in png_set_read_fn() and png_set_write_fn().
+
+Version 1.4.0beta50 [March 18, 2009]
+  Use png_calloc() instead of png_malloc() to allocate big_row_buf when
+    reading an interlaced file, to avoid a possible UMR.
+  Undid revision of PNG_NO_STDIO version of png_write_flush().  Users
+    having trouble with fflush() can build with PNG_NO_WRITE_FLUSH defined
+    or supply their own flush_fn() replacement.
+  Revised libpng*.txt and png.h documentation about use of png_write_flush()
+    and png_set_write_fn().
+  Removed fflush() from pngtest.c.
+  Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
+
+Version 1.4.0beta51 [March 21, 2009]
+  Removed new png_fileno() macro from pngconf.h .
+
+Version 1.4.0beta52 [March 27, 2009]
+  Relocated png_do_chop() ahead of building gamma tables in pngrtran.c
+    This avoids building 16-bit gamma tables unnecessarily.
+  Removed fflush() from pngtest.c.
+  Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
+  Added a section on differences between 1.0.x and 1.2.x to libpng.3/libpng.txt
+
+Version 1.4.0beta53 [April 1, 2009]
+  Removed some remaining MMX macros from pngpriv.h
+  Fixed potential memory leak of "new_name" in png_write_iCCP() (Ralph Giles)
+
+Version 1.4.0beta54 [April 13, 2009]
+  Added "ifndef PNG_SKIP_SETJMP_CHECK" block in pngconf.h to allow
+    application code writers to bypass the check for multiple inclusion
+    of setjmp.h when they know that it is safe to ignore the situation.
+  Eliminated internal use of setjmp() in pngread.c and pngwrite.c
+  Reordered ancillary chunks in pngtest.png to be the same as what
+    pngtest now produces, and made some cosmetic changes to pngtest output.
+  Eliminated deprecated png_read_init_3() and png_write_init_3() functions.
+
+Version 1.4.0beta55 [April 15, 2009]
+  Simplified error handling in pngread.c and pngwrite.c by putting
+    the new png_read_cleanup() and png_write_cleanup() functions inline.
+
+Version 1.4.0beta56 [April 25, 2009]
+  Renamed "user_chunk_data" to "my_user_chunk_data" in pngtest.c to suppress
+    "shadowed declaration" warning from gcc-4.3.3.
+  Renamed "gamma" to "png_gamma" in pngset.c to avoid "shadowed declaration"
+    warning about a global "gamma" variable in math.h on some platforms.
+
+Version 1.4.0beta57 [May 2, 2009]
+  Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
+    but was never defined (again).
+  Rebuilt configure scripts with autoconf-2.63 instead of 2.62
+  Removed pngprefs.h and MMX from makefiles
+
+Version 1.4.0beta58 [May 14, 2009]
+  Changed pngw32.def to pngwin.def in makefile.mingw (typo was introduced
+    in beta57).
+  Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri)
+
+Version 1.4.0beta59 [May 15, 2009]
+  Reformatted sources in libpng style (3-space indentation, comment format)
+  Fixed typo in libpng docs (PNG_FILTER_AVE should be PNG_FILTER_AVG)
+  Added sections about the git repository and our coding style to the
+    documentation
+  Relocated misplaced #endif in pngwrite.c, sCAL chunk handler.
+
+Version 1.4.0beta60 [May 19, 2009]
+  Conditionally compile png_read_finish_row() which is not used by
+    progressive readers.
+  Added contrib/pngminim/preader to demonstrate building minimal progressive
+    decoder, based on contrib/gregbook with embedded libpng and zlib.
+
+Version 1.4.0beta61 [May 20, 2009]
+  In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there
+    is only one makefile in those directories, and revised the README files
+    accordingly.
+  More reformatting of comments, mostly to capitalize sentences.
+
+Version 1.4.0beta62 [June 2, 2009]
+  Added "#define PNG_NO_WRITE_SWAP" to contrib/pngminim/encoder/pngusr.h
+    and "define PNG_NO_READ_SWAP" to decoder/pngusr.h and preader/pngusr.h
+  Reformatted several remaining "else statement" into two lines.
+  Added a section to the libpng documentation about using png_get_io_ptr()
+    in configure scripts to detect the presence of libpng.
+
+Version 1.4.0beta63 [June 15, 2009]
+  Revised libpng*.txt and libpng.3 to mention calling png_set_IHDR()
+    multiple times and to specify the sample order in the tRNS chunk,
+    because the ISO PNG specification has a typo in the tRNS table.
+  Changed several PNG_UNKNOWN_CHUNK_SUPPORTED to
+    PNG_HANDLE_AS_UNKNOWN_SUPPORTED, to make the png_set_keep mechanism
+    available for ignoring known chunks even when not saving unknown chunks.
+  Adopted preference for consistent use of "#ifdef" and "#ifndef" versus
+    "#if defined()" and "if !defined()" where possible.
+
+Version 1.4.0beta64 [June 24, 2009]
+  Eliminated PNG_LEGACY_SUPPORTED code.
+  Moved the various unknown chunk macro definitions outside of the
+    PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks.
+
+Version 1.4.0beta65 [June 26, 2009]
+  Added a reference to the libpng license in each file.
+
+Version 1.4.0beta66 [June 27, 2009]
+  Refer to the libpng license instead of the libpng license in each file.
+
+Version 1.4.0beta67 [July 6, 2009]
+  Relocated INVERT_ALPHA within png_read_png() and png_write_png().
+  Added high-level API transform PNG_TRANSFORM_GRAY_TO_RGB.
+  Added an "xcode" project to the projects directory (Alam Arias).
+
+Version 1.4.0beta68 [July 19, 2009]
+  Avoid some tests in filter selection in pngwutil.c
+
+Version 1.4.0beta69 [July 25, 2009]
+  Simplified the new filter-selection test.  This runs faster in the
+    common "PNG_ALL_FILTERS" and PNG_FILTER_NONE cases.
+  Removed extraneous declaration from the new call to png_read_gray_to_rgb()
+    (bug introduced in libpng-1.4.0beta67).
+  Fixed up xcode project (Alam Arias)
+  Added a prototype for png_64bit_product() in png.c
+
+Version 1.4.0beta70 [July 27, 2009]
+  Avoid a possible NULL dereference in debug build, in png_set_text_2().
+    (bug introduced in libpng-0.95, discovered by Evan Rouault)
+
+Version 1.4.0beta71 [July 29, 2009]
+  Rebuilt configure scripts with autoconf-2.64.
+
+Version 1.4.0beta72 [August 1, 2009]
+  Replaced *.tar.lzma with *.tar.xz in distribution.  Get the xz codec
+    from <http://tukaani.org/xz>.
+
+Version 1.4.0beta73 [August 1, 2009]
+  Reject attempt to write iCCP chunk with negative embedded profile length
+    (JD Chen) (CVE-2009-5063).
+
+Version 1.4.0beta74 [August 8, 2009]
+  Changed png_ptr and info_ptr member "trans" to "trans_alpha".
+
+Version 1.4.0beta75 [August 21, 2009]
+  Removed an extra png_debug() recently added to png_write_find_filter().
+  Fixed incorrect #ifdef in pngset.c regarding unknown chunk support.
+
+Version 1.4.0beta76 [August 22, 2009]
+  Moved an incorrectly located test in png_read_row() in pngread.c
+
+Version 1.4.0beta77 [August 27, 2009]
+  Removed lpXYZ.tar.bz2 (with CRLF), KNOWNBUG, libpng-x.y.z-KNOWNBUG.txt,
+    and the "noconfig" files from the distribution.
+  Moved CMakeLists.txt from scripts into the main libpng directory.
+  Various bugfixes and improvements to CMakeLists.txt (Philip Lowman)
+
+Version 1.4.0beta78 [August 31, 2009]
+  Converted all PNG_NO_* tests to PNG_*_SUPPORTED everywhere except pngconf.h
+  Eliminated PNG_NO_FREE_ME and PNG_FREE_ME_SUPPORTED macros.
+  Use png_malloc plus a loop instead of png_calloc() to initialize
+    row_pointers in png_read_png().
+
+Version 1.4.0beta79 [September 1, 2009]
+  Eliminated PNG_GLOBAL_ARRAYS and PNG_LOCAL_ARRAYS; always use local arrays.
+  Eliminated PNG_CALLOC_SUPPORTED macro and always provide png_calloc().
+
+Version 1.4.0beta80 [September 17, 2009]
+  Removed scripts/libpng.icc
+  Changed typecast of filler from png_byte to png_uint_16 in png_set_filler().
+    (Dennis Gustafsson)
+  Fixed typo introduced in beta78 in pngtest.c ("#if def " should be "#ifdef ")
+
+Version 1.4.0beta81 [September 23, 2009]
+  Eliminated unused PNG_FLAG_FREE_* defines from pngpriv.h
+  Expanded TAB characters in pngrtran.c
+  Removed PNG_CONST from all "PNG_CONST PNG_CHNK" declarations to avoid
+    compiler complaints about doubly declaring things "const".
+  Changed all "#if [!]defined(X)" to "if[n]def X" where possible.
+  Eliminated unused png_ptr->row_buf_size
+
+Version 1.4.0beta82 [September 25, 2009]
+  Moved redundant IHDR checking into new png_check_IHDR() in png.c
+    and report all errors found in the IHDR data.
+  Eliminated useless call to png_check_cHRM() from pngset.c
+
+Version 1.4.0beta83 [September 25, 2009]
+  Revised png_check_IHDR() to eliminate bogus complaint about filter_type.
+
+Version 1.4.0beta84 [September 30, 2009]
+  Fixed some inconsistent indentation in pngconf.h
+  Revised png_check_IHDR() to add a test for width variable less than 32-bit.
+
+Version 1.4.0beta85 [October 1, 2009]
+  Revised png_check_IHDR() again, to check info_ptr members instead of
+    the contents of the returned parameters.
+
+Version 1.4.0beta86 [October 9, 2009]
+  Updated the "xcode" project (Alam Arias).
+  Eliminated a shadowed declaration of "pp" in png_handle_sPLT().
+
+Version 1.4.0rc01 [October 19, 2009]
+  Trivial cosmetic changes.
+
+Version 1.4.0beta87 [October 30, 2009]
+  Moved version 1.4.0 back into beta.
+
+Version 1.4.0beta88 [October 30, 2009]
+  Revised libpng*.txt section about differences between 1.2.x and 1.4.0
+    because most of the new features have now been ported back to 1.2.41
+
+Version 1.4.0beta89 [November 1, 2009]
+  More bugfixes and improvements to CMakeLists.txt (Philip Lowman)
+  Removed a harmless extra png_set_invert_alpha() from pngwrite.c
+  Apply png_user_chunk_cache_max within png_decompress_chunk().
+  Merged libpng-1.2.41.txt with libpng-1.4.0.txt where appropriate.
+
+Version 1.4.0beta90 [November 2, 2009]
+  Removed all remaining WIN32_WCE #ifdefs except those involving the
+    time.h "tm" structure
+
+Version 1.4.0beta91 [November 3, 2009]
+  Updated scripts/pngw32.def and projects/wince/png32ce.def
+  Copied projects/wince/png32ce.def to the scripts directory.
+  Added scripts/makefile.wce
+  Patched ltmain.sh for wince support.
+  Added PNG_CONVERT_tIME_SUPPORTED macro.
+
+Version 1.4.0beta92 [November 4, 2009]
+  Make inclusion of time.h in pngconf.h depend on PNG_CONVERT_tIME_SUPPORTED
+  Make #define PNG_CONVERT_tIME_SUPPORTED depend on PNG_WRITE_tIME_SUPPORTED
+  Revised libpng*.txt to describe differences from 1.2.40 to 1.4.0 (instead
+    of differences from 1.2.41 to 1.4.0)
+
+Version 1.4.0beta93 [November 7, 2009]
+  Added PNG_DEPSTRUCT, PNG_DEPRECATED, PNG_USE_RESULT, PNG_NORETURN, and
+    PNG_ALLOCATED macros to detect deprecated direct access to the
+    png_struct or info_struct members and other deprecated usage in
+    applications (John Bowler).
+  Updated scripts/makefile* to add "-DPNG_CONFIGURE_LIBPNG" to CFLAGS,
+    to prevent warnings about direct access to png structs by libpng
+    functions while building libpng.  They need to be tested, especially
+    those using compilers other than gcc.
+  Updated projects/visualc6 and visualc71 with "/d PNG_CONFIGURE_LIBPNG".
+    They should work but still need to be updated to remove
+    references to pnggccrd.c or pngvcrd.c and ASM building.
+  Added README.txt to the beos, cbuilder5, netware, and xcode projects warning
+    that they need to be updated, to remove references to pnggccrd.c and
+    pngvcrd.c and to depend on pngpriv.h
+  Removed three direct references to read_info_ptr members in pngtest.c
+    that were detected by the new PNG_DEPSTRUCT macro.
+  Moved the png_debug macro definitions and the png_read_destroy(),
+    png_write_destroy() and png_far_to_near() prototypes from png.h
+    to pngpriv.h (John Bowler)
+  Moved the synopsis lines for png_read_destroy(), png_write_destroy()
+    png_debug(), png_debug1(), and png_debug2() from libpng.3 to libpngpf.3.
+
+Version 1.4.0beta94 [November 9, 2009]
+  Removed the obsolete, unused pnggccrd.c and pngvcrd.c files.
+  Updated CMakeLists.txt to add "-DPNG_CONFIGURE_LIBPNG" to the definitions.
+  Removed dependency of pngtest.o on pngpriv.h in the makefiles.
+  Only #define PNG_DEPSTRUCT, etc. in pngconf.h if not already defined.
+
+Version 1.4.0beta95 [November 10, 2009]
+  Changed png_check_sig() to !png_sig_cmp() in contrib programs.
+  Added -DPNG_CONFIGURE_LIBPNG to contrib/pngminm/*/makefile
+  Changed png_check_sig() to !png_sig_cmp() in contrib programs.
+  Corrected the png_get_IHDR() call in contrib/gregbook/readpng2.c
+  Changed pngminim/*/gather.sh to stop trying to remove pnggccrd.c and pngvcrd.c
+  Added dependency on pngpriv.h in contrib/pngminim/*/makefile
+
+Version 1.4.0beta96 [November 12, 2009]
+  Renamed scripts/makefile.wce to scripts/makefile.cegcc
+  Revised Makefile.am to use libpng.sys while building libpng.so
+    so that only PNG_EXPORT functions are exported.
+  Removed the deprecated png_check_sig() function/macro.
+  Removed recently removed function names from scripts/*.def
+  Revised pngtest.png to put chunks in the same order written by pngtest
+    (evidently the same change made in libpng-1.0beta54 was lost).
+  Added PNG_PRIVATE macro definition in pngconf.h for possible future use.
+
+Version 1.4.0beta97 [November 13, 2009]
+  Restored pngtest.png to the libpng-1.4.0beta7 version.
+  Removed projects/beos and netware.txt; no one seems to be supporting them.
+  Revised Makefile.in
+
+Version 1.4.0beta98 [November 13, 2009]
+  Added the "xcode" project to zip distributions,
+  Fixed a typo in scripts/pngwin.def introduced in beta97.
+
+Version 1.4.0beta99 [November 14, 2009]
+  Moved libpng-config.in and libpng.pc-configure.in out of the scripts
+    directory, to libpng-config.in and libpng-pc.in, respectively, and
+    modified Makefile.am and configure.ac accordingly.  Now "configure"
+    needs nothing from the "scripts" directory.
+  Avoid redefining PNG_CONST in pngconf.h
+
+Version 1.4.0beta100 [November 14, 2009]
+  Removed ASM builds from projects/visualc6 and projects/visualc71
+  Removed scripts/makefile.nommx and makefile.vcawin32
+  Revised CMakeLists.txt to account for new location of libpng-config.in
+    and libpng-pc.in
+  Updated INSTALL to reflect removal and relocation of files.
+
+Version 1.4.0beta101 [November 14, 2009]
+  Restored the binary files (*.jpg, *.png, some project files) that were
+    accidentally deleted from the zip and 7z distributions when the xcode
+    project was added.
+
+Version 1.4.0beta102 [November 18, 2009]
+  Added libpng-config.in and libpng-pc.in to the zip and 7z distributions.
+  Fixed a typo in projects/visualc6/pngtest.dsp, introduced in beta100.
+  Moved descriptions of makefiles and other scripts out of INSTALL into
+    scripts/README.txt
+  Updated the copyright year in scripts/pngwin.rc from 2006 to 2009.
+
+Version 1.4.0beta103 [November 21, 2009]
+  Removed obsolete comments about ASM from projects/visualc71/README_zlib.txt
+  Align row_buf on 16-byte boundary in memory.
+  Restored the PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED guard around the call
+    to png_flush() after png_write_IEND().  See 1.4.0beta32, 1.4.0beta50
+    changes above and 1.2.30, 1.2.30rc01 and rc03 in 1.2.41 CHANGES.  Someone
+    needs this feature.
+  Make the 'png_jmpbuf' macro expand to a call that records the correct
+    longjmp function as well as returning a pointer to the setjmp
+    jmp_buf buffer, and marked direct access to jmpbuf 'deprecated'.
+    (John Bowler)
+
+Version 1.4.0beta104 [November 22, 2009]
+  Removed png_longjmp_ptr from scripts/*.def and libpng.3
+  Rebuilt configure scripts with autoconf-2.65
+
+Version 1.4.0beta105 [November 25, 2009]
+  Use fast integer PNG_DIVIDE_BY_255() or PNG_DIVIDE_BY_65535()
+    to accomplish alpha premultiplication when
+    PNG_READ_COMPOSITE_NODIV_SUPPORTED is defined.
+  Changed "/255" to "/255.0" in background calculations to make it clear
+    that the 255 is used as a double.
+
+Version 1.4.0beta106 [November 27, 2009]
+  Removed premultiplied alpha feature.
+
+Version 1.4.0beta107 [December 4, 2009]
+  Updated README
+  Added "#define PNG_NO_PEDANTIC_WARNINGS" in the libpng source files.
+  Removed "-DPNG_CONFIGURE_LIBPNG" from the makefiles and projects.
+  Revised scripts/makefile.netbsd, makefile.openbsd, and makefile.sco
+    to put png.h and pngconf.h in $prefix/include, like the other scripts,
+    instead of in $prefix/include/libpng.  Also revised makefile.sco
+    to put them in $prefix/include/libpng15 instead of in
+    $prefix/include/libpng/libpng15.
+
+Version 1.4.0beta108 [December 11, 2009]
+  Removed leftover "-DPNG_CONFIGURE_LIBPNG" from contrib/pngminim/*/makefile
+  Relocated png_do_chop() to its original position in pngrtran.c; the
+    change in version 1.2.41beta08 caused transparency to be handled wrong
+    in some 16-bit datastreams (Yusaku Sugai).
+
+Version 1.4.0beta109 [December 13, 2009]
+  Added "bit_depth" parameter to the private png_build_gamma_table() function.
+  Pass bit_depth=8 to png_build_gamma_table() when bit_depth is 16 but the
+    PNG_16_TO_8 transform has been set, to avoid unnecessary build of 16-bit
+    tables.
+
+Version 1.4.0rc02 [December 20, 2009]
+  Declared png_cleanup_needed "volatile" in pngread.c and pngwrite.c
+
+Version 1.4.0rc03 [December 22, 2009]
+  Renamed libpng-pc.in back to libpng.pc.in and revised CMakeLists.txt
+    (revising the change in 1.4.0beta99)
+
+Version 1.4.0rc04 [December 25, 2009]
+  Swapped PNG_UNKNOWN_CHUNKS_SUPPORTED and PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+    in pngset.c to be consistent with other changes in version 1.2.38.
+
+Version 1.4.0rc05 [December 25, 2009]
+  Changed "libpng-pc.in" to "libpng.pc.in" in configure.ac, configure, and
+    Makefile.in to be consistent with changes in libpng-1.4.0rc03
+
+Version 1.4.0rc06 [December 29, 2009]
+  Reverted the gamma_table changes from libpng-1.4.0beta109.
+  Fixed some indentation errors.
+
+Version 1.4.0rc07 [January 1, 2010]
+  Revised libpng*.txt and libpng.3 about 1.2.x->1.4.x differences.
+  Use png_calloc() instead of png_malloc(); png_memset() in pngrutil.c
+  Update copyright year to 2010.
+
+Version 1.4.0rc08 [January 2, 2010]
+  Avoid deprecated references to png_ptr-io_ptr and png_ptr->error_ptr
+    in pngtest.c
+
+Version 1.4.0 [January 3, 2010]
+  No changes.
+
+Version 1.4.1beta01 [January 8, 2010]
+  Updated CMakeLists.txt for consistent indentation and to avoid an
+    unclosed if-statement warning (Philip Lowman).
+  Revised Makefile.am and Makefile.in to remove references to Y2KINFO,
+    KNOWNBUG, and libpng.la (Robert Schwebel).
+  Revised the makefiles to install the same files and symbolic
+    links as configure, except for libpng.la and libpng14.la.
+  Make png_set|get_compression_buffer_size() available even when
+    PNG_WRITE_SUPPORTED is not enabled.
+  Revised Makefile.am and Makefile.in to simplify their maintenance.
+  Revised scripts/makefile.linux to install a link to libpng14.so.14.1
+
+Version 1.4.1beta02 [January 9, 2010]
+  Revised the rest of the makefiles to install a link to libpng14.so.14.1
+
+Version 1.4.1beta03 [January 10, 2010]
+  Removed png_set_premultiply_alpha() from scripts/*.def
+
+Version 1.4.1rc01 [January 16, 2010]
+  No changes.
+
+Version 1.4.1beta04 [January 23, 2010]
+  Revised png_decompress_chunk() to improve speed and memory usage when
+    decoding large chunks.
+  Added png_set|get_chunk_malloc_max() functions.
+
+Version 1.4.1beta05 [January 26, 2010]
+  Relocated "int k" declaration in pngtest.c to minimize its scope.
+
+Version 1.4.1beta06 [January 28, 2010]
+  Revised png_decompress_chunk() to use a two-pass method suggested by
+    John Bowler.
+
+Version 1.4.1beta07 [February 6, 2010]
+  Folded some long lines in the source files.
+  Added definable PNG_USER_CHUNK_CACHE_MAX, PNG_USER_CHUNK_MALLOC_MAX,
+    and a PNG_USER_LIMITS_SUPPORTED flag.
+  Eliminated use of png_ptr->irowbytes and reused the slot in png_ptr as
+    png_ptr->png_user_chunk_malloc_max.
+  Revised png_push_save_buffer() to do fewer but larger png_malloc() calls.
+
+Version 1.4.1beta08 [February 6, 2010]
+  Minor cleanup and updating of dates and copyright year.
+
+Version 1.5.0beta01 [February 7, 2010]
+  Moved declaration of png_struct into private pngstruct.h and png_info
+    into pnginfo.h
+
+Version 1.4.1beta09 and 1.5.0beta02 [February 7, 2010]
+  Reverted to original png_push_save_buffer() code.
+
+Version 1.4.1beta10 and 1.5.0beta03 [February 8, 2010]
+  Return allocated "old_buffer" in png_push_save_buffer() before
+    calling png_error(), to avoid a potential memory leak.
+  Updated configure script to use SO number 15.
+
+Version 1.5.0beta04 [February 9, 2010]
+  Removed malformed "incomplete struct declaration" of png_info from png.h
+
+Version 1.5.0beta05 [February 12, 2010]
+  Removed PNG_DEPSTRUCT markup in pngstruct.h and pnginfo.h, and undid the
+    linewrapping that it entailed.
+  Revised comments in pngstruct.h and pnginfo.h and added pointers to
+    the libpng license.
+  Changed PNG_INTERNAL to PNG_EXPOSE_INTERNAL_STRUCTURES
+  Removed the cbuilder5 project, which has not been updated to 1.4.0.
+
+Version 1.4.1beta12 and 1.5.0beta06 [February 14, 2010]
+  Fixed type declaration of png_get_chunk_malloc_max() in pngget.c (Daisuke
+    Nishikawa)
+
+Version 1.5.0beta07 [omitted]
+
+Version 1.5.0beta08 [February 19, 2010]
+  Changed #ifdef PNG_NO_STDIO_SUPPORTED to #ifdef PNG_NO_CONSOLE_IO_SUPPORTED
+    wherever png_snprintf() is used to construct error and warning messages.
+  Noted in scripts/makefile.mingw that it expects to be run under MSYS.
+  Removed obsolete unused MMX-querying support from contrib/gregbook
+  Added exported png_longjmp() function.
+  Removed the AIX redefinition of jmpbuf in png.h
+  Added -D_ALLSOURCE in configure.ac, makefile.aix, and CMakeLists.txt
+    when building on AIX.
+
+Version 1.5.0beta09 [February 19, 2010]
+  Removed -D_ALLSOURCE from configure.ac, makefile.aix, and CMakeLists.txt.
+  Changed the name of png_ptr->jmpbuf to png_ptr->png_jmpbuf in pngstruct.h
+
+Version 1.5.0beta10 [February 25, 2010]
+  Removed unused gzio.c from contrib/pngminim gather and makefile scripts
+  Removed replacement error handlers from contrib/gregbook.  Because of
+    the new png_longjmp() function they are no longer needed.
+
+Version 1.5.0beta11 [March 6, 2010]
+  Removed checking for already-included setjmp.h from pngconf.h
+  Fixed inconsistent indentations and made numerous cosmetic changes.
+  Revised the "SEE ALSO" style of libpng.3, libpngpf.3, and png.5
+
+Version 1.5.0beta12 [March 9, 2010]
+  Moved "#include png.h" inside pngpriv.h and removed "#include png.h" from
+    the source files, along with "#define PNG_EXPOSE_INTERNAL_STRUCTURES"
+    and "#define PNG_NO_PEDANTIC_WARNINGS" (John Bowler).
+  Created new pngdebug.h and moved debug definitions there.
+
+Version 1.5.0beta13 [March 10, 2010]
+  Protect pngstruct.h, pnginfo.h, and pngdebug.h from being included twice.
+  Revise the "#ifdef" blocks in png_inflate() so it will compile when neither
+    PNG_USER_CHUNK_MALLOC_MAX nor PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
+    is defined.
+  Removed unused png_measure_compressed_chunk() from pngpriv.h and libpngpf.3
+  Moved the 'config.h' support from pngconf.h to pngpriv.h
+  Removed PNGAPI from the png_longjmp_ptr typedef.
+  Eliminated dependence of pngtest.c on the private pngdebug.h file.
+  Make all png_debug macros into *unterminated* statements or
+    expressions (i.e. a trailing ';' must always be added) and correct
+    the format statements in various png_debug messages.
+
+Version 1.5.0beta14 [March 14, 2010]
+  Removed direct access to png_ptr->io_ptr from the Windows code in pngtest.c
+  Revised Makefile.am to account for recent additions and replacements.
+  Corrected CE and OS/2 DEF files (scripts/png*def) for symbols removed and
+    added ordinal numbers to the Windows DEF file and corrected the duplicated
+    ordinal numbers on CE symbols that are commented out.
+  Added back in export symbols that can be present in the Windows build but
+    are disabled by default.
+  PNG_EXPORT changed to include an 'ordinal' field for DEF file generation.
+    PNG_CALLBACK added to make callback definitions uniform.  PNGAPI split
+    into PNGCAPI (base C form), PNGAPI (exports) and PNGCBAPI (callbacks),
+    and appropriate changes made to all files.  Cygwin builds re-hinged to
+    allow procedure call standard changes and to remove the need for the DEF
+    file (fixes build on Cygwin).
+  Enabled 'attribute' warnings that are relevant to library APIs and callbacks.
+  Changed rules for generation of the various symbol files and added a new
+    rule for a DEF file (which is also added to the distribution).
+  Updated the symbol file generation to stop it adding spurious spaces
+    to EOL (coming from preprocessor macro expansion).  Added a facility
+    to join tokens in the output and rewrite *.dfn to use this.
+  Eliminated scripts/*.def in favor of libpng.def; updated projects/visualc71
+    and removed scripts/makefile.cygwin.
+  Made PNG_BUILD_DLL safe: it can be set whenever a DLL is being built.
+  Removed the include of sys/types.h - apparently unnecessary now on the
+    platforms on which it happened (all but Mac OS and RISC OS).
+  Moved the Mac OS test into pngpriv.h (the only place it is used.)
+
+Version 1.5.0beta15 [March 17, 2010]
+  Added symbols.chk target to Makefile.am to validate the symbols in png.h
+    against the new DEF file scripts/symbols.def.
+  Changed the default DEF file back to pngwin.def.
+  Removed makefile.mingw.
+  Eliminated PNG_NO_EXTERN and PNG_ALL_EXTERN
+
+Version 1.5.0beta16 [April 1, 2010]
+  Make png_text_struct independent of PNG_iTXt_SUPPORTED, so that
+    fields are initialized in all configurations.  The READ/WRITE
+    macros (PNG_(READ|WRITE)_iTXt_SUPPORTED) still function as
+    before to disable code to actually read or write iTXt chunks
+    and iTXt_SUPPORTED can be used to detect presence of either
+    read or write support (but it is probably better to check for
+    the one actually required - read or write.)
+  Combined multiple png_warning() calls for a single error.
+  Restored the macro definition of png_check_sig().
+
+Version 1.5.0beta17 [April 17, 2010]
+  Added some "(long)" typecasts to printf calls in png_handle_cHRM().
+  Documented the fact that png_set_dither() was disabled since libpng-1.4.0.
+  Reenabled png_set_dither() but renamed it to png_set_quantize() to reflect
+    more accurately what it actually does.  At the same time, renamed
+    the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros to
+    PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS.
+  Added some "(long)" typecasts to printf calls in png_handle_cHRM().
+  Freeze build-time only configuration in the build.
+    In all prior versions of libpng most configuration options
+    controlled by compiler #defines had to be repeated by the
+    application code that used libpng.  This patch changes this
+    so that compilation options that can only be changed at build
+    time are frozen in the build.  Options that are compiler
+    dependent (and those that are system dependent) are evaluated
+    each time - pngconf.h holds these.  Options that can be changed
+    per-file in the application are in png.h.  Frozen options are
+    in the new installed header file pnglibconf.h (John Bowler)
+  Removed the xcode project because it has not been updated to work
+    with libpng-1.5.0.
+  Removed the ability to include optional pngusr.h
+
+Version 1.5.0beta18 [April 17, 2010]
+  Restored the ability to include optional pngusr.h
+  Moved replacements for png_error() and png_warning() from the
+    contrib/pngminim project to pngerror.c, for use when warnings or
+    errors are disabled via PNG_NO_WARN or PNG_NO_ERROR_TEXT, to avoid
+    storing unneeded error/warning text.
+  Updated contrib/pngminim project to work with the new pnglibconf.h
+  Added some PNG_NO_* defines to contrib/pngminim/*/pngusr.h to save space.
+
+Version 1.5.0beta19 [April 24, 2010]
+  Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the functions
+    to read and write ints to be disabled independently of PNG_USE_READ_MACROS,
+    which allows libpng to be built with the functions even though the default
+    is to use the macros - this allows applications to choose at app build
+    time whether or not to use macros (previously impossible because the
+    functions weren't in the default build.)
+  Changed Windows calling convention back to __cdecl for API functions.
+    For Windows/x86 platforms only:
+      __stdcall is no longer needed for Visual Basic, so libpng-1.5.0 uses
+      __cdecl throughout (both API functions and callbacks) on Windows/x86
+      platforms.
+  Replaced visualc6 and visualc71 projects with new vstudio project
+  Relaxed the overly-restrictive permissions of some files.
+
+Version 1.5.0beta20 [April 24, 2010]
+  Relaxed more overly-restrictive permissions of some files.
+
+Version 1.5.0beta21 [April 27, 2010]
+  Removed some unwanted binary bytes and changed CRLF to NEWLINE in the new
+    vstudio project files, and some trivial editing of some files in the
+    scripts directory.
+  Set PNG_NO_READ_BGR, PNG_NO_IO_STATE, and PNG_NO_TIME_RFC1123 in
+    contrib/pngminim/decoder/pngusr.h to make a smaller decoder application.
+
+Version 1.5.0beta22 [April 28, 2010]
+  Fixed dependencies of GET_INT_32 - it does not require READ_INT_FUNCTIONS
+    because it has a macro equivalent.
+  Improved the options.awk script; added an "everything off" option.
+  Revised contrib/pngminim to use the "everything off" option in pngusr.dfa.
+
+Version 1.5.0beta23 [April 29, 2010]
+  Corrected PNG_REMOVED macro to take five arguments.
+    The macro was documented with two arguments (name,ordinal), however
+    the symbol checking .dfn files assumed five arguments.  The five
+    argument form seems more useful so it is changed to that.
+  Corrected PNG_UNKNOWN_CHUNKS_SUPPORTED to PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+    in gregbook/readpng2.c
+  Corrected protection of png_get_user_transform_ptr. The API declaration in
+    png.h is removed if both READ and WRITE USER_TRANSFORM are turned off
+    but was left defined in pngtrans.c
+  Added logunsupported=1 to cause pnglibconf.h to document disabled options.
+    This makes the installed pnglibconf.h more readable but causes no
+    other change.  The intention is that users of libpng will find it
+    easier to understand if an API they need is missing.
+  Include png_reset_zstream() in png.c only when PNG_READ_SUPPORTED is defined.
+  Removed dummy_inflate.c from contrib/pngminim/encoder
+  Removed contrib/pngminim/*/gather.sh; gathering is now done in the makefile.
+
+Version 1.5.0beta24 [May 7, 2010]
+  Use bitwise "&" instead of arithmetic mod in pngrutil.c calculation of the
+    offset of the png_ptr->rowbuf pointer into png_ptr->big_row_buf.
+  Added more blank lines for readability.
+
+Version 1.5.0beta25 [June 18, 2010]
+  In pngpread.c: png_push_have_row() add check for new_row > height
+  Removed the now-redundant check for out-of-bounds new_row from example.c
+
+Version 1.5.0beta26 [June 18, 2010]
+  In pngpread.c: png_push_process_row() add check for too many rows.
+
+Version 1.5.0beta27 [June 18, 2010]
+  Removed the check added in beta25 as it is now redundant.
+
+Version 1.5.0beta28 [June 20, 2010]
+  Rewrote png_process_IDAT_data to consistently treat extra data as warnings
+    and handle end conditions more cleanly.
+  Removed the new (beta26) check in png_push_process_row().
+
+Version 1.5.0beta29 [June 21, 2010]
+  Revised scripts/options.awk to work on Sunos (but still doesn't work)
+  Added comment to options.awk and contrib/pngminim/*/makefile to try nawk.
+
+Version 1.5.0beta30 [June 22, 2010]
+  Stop memory leak when reading a malformed sCAL chunk.
+
+Version 1.5.0beta31 [June 26, 2010]
+  Revised pngpread.c patch of beta28 to avoid an endless loop.
+  Removed some trailing blanks.
+
+Version 1.5.0beta32 [June 26, 2010]
+  Removed leftover scripts/options.patch and scripts/options.rej
+
+Version 1.5.0beta33 [July 6, 3010]
+  Made FIXED and FLOATING options consistent in the APIs they enable and
+    disable.  Corrected scripts/options.awk to handle both command line
+    options and options specified in the .dfa files.
+  Changed char *msg to PNG_CONST char *msg in pngrutil.c
+  Make png_set_sRGB_gAMA_and_cHRM set values using either the fixed or
+    floating point APIs, but not both.
+  Reversed patch to remove error handler when the jmp_buf is stored in the
+    main program structure, not the png_struct.
+    The error handler is needed because the default handler in libpng will
+    always use the jmp_buf in the library control structure; this is never
+    set.  The gregbook code is a useful example because, even though it
+    uses setjmp/longjmp, it shows how error handling can be implemented
+    using control mechanisms not directly supported by libpng.  The
+    technique will work correctly with mechanisms such as Microsoft
+    Structure Exceptions or C++ exceptions (compiler willing - note that gcc
+    does not by default support interworking of C and C++ error handling.)
+  Reverted changes to call png_longjmp in contrib/gregbook where it is not
+    appropriate.  If mainprog->jmpbuf is used by setjmp, then png_longjmp
+    cannot be used.
+  Changed "extern PNG_EXPORT" to "PNG_EXPORT" in png.h (Jan Nijtmans)
+  Changed "extern" to "PNG_EXTERN" in pngpriv.h (except for the 'extern "C" {')
+
+Version 1.5.0beta34 [July 12, 2010]
+  Put #ifndef PNG_EXTERN, #endif around the define PNG_EXTERN in pngpriv.h
+
+Version 1.5.0beta35 [July 24, 2010]
+  Removed some newly-added TAB characters.
+  Added -DNO_PNG_SNPRINTF to CFLAGS in scripts/makefile.dj2
+  Moved the definition of png_snprintf() outside of the enclosing
+    #ifdef blocks in pngconf.h
+
+Version 1.5.0beta36 [July 29, 2010]
+  Patches by John Bowler:
+  Fixed point APIs are now supported throughout (no missing APIs).
+  Internal fixed point arithmetic support exists for all internal floating
+    point operations.
+  sCAL validates the floating point strings it is passed.
+  Safe, albeit rudimentary, Watcom support is provided by PNG_API_RULE==2
+  Two new APIs exist to get the number of passes without turning on the
+    PNG_INTERLACE transform and to get the number of rows in the current
+    pass.
+  A new test program, pngvalid.c, validates the gamma code.
+  Errors in the 16-bit gamma correction (overflows) have been corrected.
+  cHRM chunk testing is done consistently (previously the floating point
+    API bypassed it, because the test really didn't work on FP, now the test
+    is performed on the actual values to be stored in the PNG file so it
+    works in the FP case too.)
+  Most floating point APIs now simply call the fixed point APIs after
+    converting the values to the fixed point form used in the PNG file.
+  The standard headers no longer include zlib.h, which is currently only
+    required for pngstruct.h and can therefore be internal.
+  Revised png_get_int_32 to undo the PNG two's complement representation of
+    negative numbers.
+
+Version 1.5.0beta37 [July 30, 2010]
+  Added a typecast in png_get_int_32() in png.h and pngrutil.h to avoid
+    a compiler warning.
+  Replaced oFFs 0,0 with oFFs -10,20 in pngtest.png
+
+Version 1.5.0beta38 [July 31, 2010]
+  Implemented remaining "_fixed" functions.
+  Corrected a number of recently introduced warnings mostly resulting from
+    safe but uncast assignments to shorter integers.  Also added a zlib
+    VStudio release library project because the latest zlib Official Windows
+    build does not include such a thing.
+  Revised png_get_int_16() to be similar to png_get_int_32().
+  Restored projects/visualc71.
+
+Version 1.5.0beta39 [August 2, 2010]
+  VisualC/GCC warning fixes, VisualC build fixes
+  The changes include support for function attributes in VC in addition to
+    those already present in GCC - necessary because without these some
+    warnings are unavoidable.  Fixes include signed/unsigned fixes in
+    pngvalid and checks with gcc -Wall -Wextra -Wunused.
+  VC requires function attributes on function definitions as well as
+    declarations, PNG_FUNCTION has been added to enable this and the
+    relevant function definitions changed.
+
+Version 1.5.0beta40 [August 6, 2010]
+  Correct use of _WINDOWS_ in pngconf.h
+  Removed png_mem_ #defines; they are no longer used.
+  Added the sRGB chunk to pngtest.png
+
+Version 1.5.0beta41 [August 11, 2010]
+  Added the cHRM chunk to pngtest.png
+  Don't try to use version-script with cygwin/mingw.
+  Revised contrib/gregbook to work under cygwin/mingw.
+
+Version 1.5.0beta42 [August 18, 2010]
+  Add .dll.a to the list of extensions to be symlinked by Makefile.am (Yaakov)
+  Made all API functions that have const arguments and constant string
+    literal pointers declare them (John Bowler).
+
+Version 1.5.0beta43 [August 20, 2010]
+  Removed spurious tabs, shorten long lines (no source change)
+    Also added scripts/chkfmt to validate the format of all the files that can
+    reasonably be validated (it is suggested to run "make distclean" before
+    checking, because some machine generated files have long lines.)
+  Reformatted the CHANGES file to be more consistent throughout.
+  Made changes to address various issues identified by GCC, mostly
+    signed/unsigned and shortening problems on assignment but also a few
+    difficult to optimize (for GCC) loops.
+  Fixed non-GCC fixed point builds.  In png.c a declaration was misplaced
+    in an earlier update.  Fixed to declare the auto variables at the head.
+  Use cexcept.h in pngvalid.c.
+
+Version 1.5.0beta44 [August 24, 2010]
+  Updated CMakeLists.txt to use CMAKE_INSTALL_LIBDIR variable; useful for
+    installing libpng in /usr/lib64 (Funda Wang).
+  Revised CMakeLists.txt to put the man pages in share/man/man* not man/man*
+  Revised CMakeLists.txt to make symlinks instead of copies when installing.
+  Changed PNG_LIB_NAME from pngNN to libpngNN in CMakeLists.txt (Philip Lowman)
+  Implemented memory checks within pngvalid
+  Reformatted/rearranged pngvalid.c to assist use of progressive reader.
+  Check interlaced images in pngvalid
+  Clarified pngusr.h comments in pnglibconf.dfa
+  Simplified the pngvalid error-handling code now that cexcept.h is in place.
+  Implemented progressive reader in pngvalid.c for standard tests
+  Implemented progressive read in pngvalid.c gamma tests
+  Turn on progressive reader in pngvalid.c by default and tidy code.
+
+Version 1.5.0beta45 [August 26, 2010]
+  Added an explicit make step to projects/vstudio for pnglibconf.h
+    Also corrected zlib.vcxproj into which Visual Studio had introduced
+    what it calls an "authoring error".  The change to make pnglibconf.h
+    simply copies the file; in the future it may actually generate the
+    file from scripts/pnglibconf.dfa as the other build systems do.
+  Changed pngvalid to work when floating point APIs are disabled
+  Renamed the prebuilt scripts/pnglibconf.h to scripts/pnglibconf.h.prebuilt
+  Supply default values for PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX
+    in pngpriv.h in case the user neglected to define them in their pngusr.h
+
+Version 1.5.0beta46 [August 28, 2010]
+  Added new private header files to libpng_sources in CMakeLists.txt
+  Added PNG_READ_16BIT, PNG_WRITE_16BIT, and PNG_16BIT options.
+  Added reference to scripts/pnglibconf.h.prebuilt in the visualc71 project.
+
+Version 1.5.0beta47 [September 11, 2010]
+  Fixed a number of problems with 64-bit compilation reported by Visual
+    Studio 2010 (John Bowler).
+
+Version 1.5.0beta48 [October 4, 2010]
+  Updated CMakeLists.txt (Philip Lowman).
+  Revised autogen.sh to recognize and use $AUTOCONF, $AUTOMAKE, $AUTOHEADER,
+    $AUTOPOINT, $ACLOCAL and $LIBTOOLIZE
+  Fixed problem with symbols creation in Makefile.am which was assuming that
+    all versions of ccp write to standard output by default (Martin Banky). The
+    bug was introduced in libpng-1.2.9beta5.
+  Removed unused mkinstalldirs.
+
+Version 1.5.0beta49 [October 8, 2010]
+  Undid Makefile.am revision of 1.5.0beta48.
+
+Version 1.5.0beta50 [October 14, 2010]
+  Revised Makefile.in to account for mkinstalldirs being removed.
+  Added some "(unsigned long)" typecasts in printf statements in pngvalid.c.
+  Suppressed a compiler warning in png_handle_sPLT().
+  Check for out-of-range text compression mode in png_set_text().
+
+Version 1.5.0beta51 [October 15, 2010]
+  Changed embedded dates to "(PENDING RELEASE) in beta releases (and future
+    rc releases) to minimize the difference between releases.
+
+Version 1.5.0beta52 [October 16, 2010]
+  Restored some of the embedded dates (in png.h, png.c, documentation, etc.)
+
+Version 1.5.0beta53 [October 18, 2010]
+  Updated INSTALL to mention using "make maintainer-clean" and to remove
+    obsolete statement about a custom ltmain.sh
+  Disabled "color-tests" by default in Makefile.am so it will work with
+    automake versions earlier than 1.11.1
+  Use document name "libpng-manual.txt" instead of "libpng-<version>.txt"
+    to simplify version differences.
+  Removed obsolete remarks about setjmp handling from INSTALL.
+  Revised and renamed the typedef in png.h and png.c that was designed
+    to catch library and header mismatch.
+
+Version 1.5.0beta54 [November 10, 2010]
+  Require 48 bytes, not 64 bytes, for big_row_buf in overflow checks.
+  Used a consistent structure for the pngget.c functions.
+
+Version 1.5.0beta55 [November 21, 2010]
+  Revised png_get_uint_32, png_get_int_32, png_get_uint_16 (Cosmin)
+  Moved reading of file signature into png_read_sig (Cosmin)
+  Fixed atomicity of chunk header serialization (Cosmin)
+  Added test for io_state in pngtest.c (Cosmin)
+  Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts.
+  Changes to remove gcc warnings (John Bowler)
+    Certain optional gcc warning flags resulted in warnings in libpng code.
+    With these changes only -Wconversion and -Wcast-qual cannot be turned on.
+    Changes are trivial rearrangements of code.  -Wconversion is not possible
+    for pngrutil.c (because of the widespread use of += et al on variables
+    smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
+    with pngwio.c and pngwutil.c because the 'write' callback and zlib
+    compression both fail to declare their input buffers with 'const'.
+
+Version 1.5.0beta56 [December 7, 2010]
+  Added the private PNG_UNUSED() macro definition in pngpriv.h.
+  Added some commentary about PNG_EXPORT in png.h and pngconf.h
+  Revised PNG_EXPORT() macro and added PNG_EXPORTA() macro, with the
+    objective of simplifying and improving the cosmetic appearance of png.h.
+  Fixed some incorrect "=" macro names in pnglibconf.dfa
+  Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt
+
+Version 1.5.0beta57 [December 9, 2010]
+  Documented the pngvalid gamma error summary with additional comments and
+    print statements.
+  Improved missing symbol handling in checksym.awk; symbols missing in both
+    the old and new files can now be optionally ignored, treated as errors
+    or warnings.
+  Removed references to pngvcrd.c and pnggccrd.c from the vstudio project.
+  Updated "libpng14" to "libpng15" in the visualc71 project.
+  Enabled the strip16 tests in pngvalid.`
+  Don't display test results (except PASS/FAIL) when running "make test".
+    Instead put them in pngtest-log.txt
+  Added "--with-zprefix=<string>" to configure.ac
+  Updated the prebuilt configuration files to autoconf version 2.68
+
+Version 1.5.0beta58 [December 19, 2010]
+  Fixed interlace image handling and add test cases (John Bowler)
+  Fixed the clean rule in Makefile.am to remove pngtest-log.txt
+  Made minor changes to work around warnings in gcc 3.4
+
+Version 1.5.0rc01 [December 27, 2010]
+  No changes.
+
+Version 1.5.0rc02 [December 27, 2010]
+  Eliminated references to the scripts/*.def files in project/visualc71.
+
+Version 1.5.0rc03 [December 28, 2010]
+  Eliminated scripts/*.def and revised Makefile.am accordingly
+
+Version 1.5.0rc04 [December 29, 2010]
+  Fixed bug in background transformation handling in pngrtran.c (it was
+    looking for the flag in png_ptr->transformations instead of in
+    png_ptr->flags) (David Raymond).
+
+Version 1.5.0rc05 [December 31, 2010]
+  Fixed typo in a comment in CMakeLists.txt (libpng14 => libpng15) (Cosmin)
+
+Version 1.5.0rc06 [January 4, 2011]
+  Changed the new configure option "zprefix=string" to "zlib-prefix=string"
+
+Version 1.5.0rc07 [January 4, 2011]
+  Updated copyright year.
+
+Version 1.5.0 [January 6, 2011]
+  No changes.
+
+version 1.5.1beta01 [January 8, 2011]
+  Added description of png_set_crc_action() to the manual.
+  Added a note in the manual that the type of the iCCP profile was changed
+    from png_charpp to png_bytepp in png_get_iCCP().  This change happened
+    in version 1.5.0beta36 but is not noted in the CHANGES.  Similarly,
+    it was changed from png_charpp to png_const_bytepp in png_set_iCCP().
+  Ensure that png_rgb_to_gray ignores palette mapped images, if libpng
+    internally happens to call it with one, and fixed a failure to handle
+    palette mapped images correctly.  This fixes CVE-2690.
+
+Version 1.5.1beta02 [January 14, 2011]
+  Fixed a bug in handling of interlaced images (bero at arklinux.org).
+  Updated CMakeLists.txt (Clifford Yapp)
+
+Version 1.5.1beta03 [January 14, 2011]
+  Fixed typecasting of some png_debug() statements (Cosmin)
+
+Version 1.5.1beta04 [January 16, 2011]
+  Updated documentation of png_set|get_tRNS() (Thomas Klausner).
+  Mentioned in the documentation that applications must #include "zlib.h"
+    if they need access to anything in zlib.h, and that a number of
+    macros such as png_memset() are no longer accessible by applications.
+  Corrected pngvalid gamma test "sample" function to access all of the color
+    samples of each pixel, instead of sampling the red channel three times.
+  Prefixed variable names index, div, exp, gamma with "png_" to avoid "shadow"
+    warnings, and (mistakenly) changed png_exp() to exp().
+
+Version 1.5.1beta05 [January 16, 2011]
+  Changed variable names png_index, png_div, png_exp, and png_gamma to
+    char_index, divisor, exp_b10, and gamma_val, respectively, and
+    changed exp() back to png_exp().
+
+Version 1.5.1beta06 [January 20, 2011]
+  Prevent png_push_crc_skip() from hanging while reading an unknown chunk
+    or an over-large compressed zTXt chunk with the progressive reader.
+  Eliminated more GCC "shadow" warnings.
+  Revised png_fixed() in png.c to avoid compiler warning about reaching the
+    end without returning anything.
+
+Version 1.5.1beta07 [January 22, 2011]
+  In the manual, describe the png_get_IHDR() arguments in the correct order.
+  Added const_png_structp and const_png_infop types, and used them in
+    prototypes for most png_get_*() functions.
+
+Version 1.5.1beta08 [January 23, 2011]
+  Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name()
+  Added synopses for the IO_STATE functions and other missing synopses
+    to the manual. Removed the synopses from libpngpf.3 because they
+    were out of date and no longer useful.  Better information can be
+    obtained by reading the prototypes and comments in pngpriv.h
+  Attempted to fix cpp on Solaris with S. Studio 12 cc, fix build
+    Added a make macro DFNCPP that is a CPP that will accept the tokens in
+    a .dfn file and adds configure stuff to test for such a CPP.  ./configure
+    should fail if one is not available.
+  Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace.
+  Added png_get_current_row_number and png_get_current_pass_number for the
+    benefit of the user transform callback.
+  Added png_process_data_pause and png_process_data_skip for the benefit of
+    progressive readers that need to stop data processing or want to optimize
+    skipping of unread data (e.g., if the reader marks a chunk to be skipped.)
+
+Version 1.5.1beta09 [January 24, 2011]
+  Enhanced pngvalid, corrected an error in gray_to_rgb, corrected doc error.
+    pngvalid contains tests of transforms, which tests are currently disabled
+    because they are incompletely tested.  gray_to_rgb was failing to expand
+    the bit depth for smaller bit depth images; this seems to be a long
+    standing error and resulted, apparently, in invalid output
+    (CVE-2011-0408, CERT VU#643140).  The documentation did not accurately
+    describe what libpng really does when converting RGB to gray.
+
+Version 1.5.1beta10 [January 27, 2010]
+  Fixed incorrect examples of callback prototypes in the manual, that were
+    introduced in libpng-1.0.0.
+  In addition the order of the png_get_uint macros with respect to the
+    relevant function definitions has been reversed.  This helps the
+    preprocessing of the symbol files be more robust.  Furthermore, the
+    symbol file preprocessing now uses -DPNG_NO_USE_READ_MACROS even when
+    the library may actually be built with PNG_USE_READ_MACROS; this stops
+    the read macros interfering with the symbol file format.
+  Made the manual, synopses, and function prototypes use the function
+    argument names file_gamma, int_file_gamma, and srgb_intent consistently.
+
+Version 1.5.1beta11 [January 28, 2011]
+  Changed PNG_UNUSED from "param=param;" to "{if(param){}}".
+  Corrected local variable type in new API png_process_data_skip()
+    The type was self-evidently incorrect but only causes problems on 64-bit
+    architectures.
+  Added transform tests to pngvalid and simplified the arguments.
+
+Version 1.5.1rc01 [January 29, 2011]
+  No changes.
+
+Version 1.5.1rc02 [January 31, 2011]
+  Added a request in the manual that applications do not use "png_" or
+    "PNG_" to begin any of their own symbols.
+  Changed PNG_UNUSED to "(void)param;" and updated the commentary in pngpriv.h
+
+Version 1.5.1 [February 3, 2011]
+  No changes.
+
+Version 1.5.2beta01 [February 13, 2011]
+  More -Wshadow fixes for older gcc compilers.  Older gcc versions apparently
+    check formal parameters names in function declarations (as well as
+    definitions) to see if they match a name in the global namespace.
+  Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the
+    old VisualC++ preprocessor.
+  Turned on interlace handling in png_read_png().
+  Fixed gcc pedantic warnings.
+  Handle longjmp in Cygwin.
+  Fixed png_get_current_row_number() in the interlaced case.
+  Cleaned up ALPHA flags and transformations.
+  Implemented expansion to 16 bits.
+
+Version 1.5.2beta02 [February 19, 2011]
+  Fixed mistake in the descriptions of user read_transform and write_transform
+    function prototypes in the manual.  The row_info struct is png_row_infop.
+  Reverted png_get_current_row_number() to previous (1.5.2beta01) behavior.
+  Corrected png_get_current_row_number documentation
+  Fixed the read/write row callback documentation.
+    This documents the current behavior, where the callback is called after
+    every row with information pertaining to the next row.
+
+Version 1.5.2beta03 [March 3, 2011]
+  Fixed scripts/makefile.vcwin32
+  Updated contrib/pngsuite/README to add the word "modify".
+  Define PNG_ALLOCATED to blank when _MSC_VER<1300.
+
+Version 1.5.2rc01 [March 19, 2011]
+  Define remaining attributes to blank when MSC_VER<1300.
+  ifdef out mask arrays in pngread.c when interlacing is not supported.
+
+Version 1.5.2rc02 [March 22, 2011]
+  Added a hint to try CPP=/bin/cpp if "cpp -E" fails in scripts/pnglibconf.mak
+    and in contrib/pngminim/*/makefile, eg., on SunOS 5.10, and removed "strip"
+    from the makefiles.
+  Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail
+    to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill)
+
+Version 1.5.2rc03 [March 24, 2011]
+  Don't include standard header files in png.h while building the symbol table,
+    to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro).
+
+Version 1.5.2 [March 31, 2011]
+  No changes.
+
+Version 1.5.3beta01 [April 1, 2011]
+  Re-initialize the zlib compressor before compressing non-IDAT chunks.
+  Added API functions (png_set_text_compression_level() and four others) to
+    set parameters for zlib compression of non-IDAT chunks.
+
+Version 1.5.3beta02 [April 3, 2011]
+  Updated scripts/symbols.def with new API functions.
+  Only compile the new zlib re-initializing code when text or iCCP is
+    supported, using PNG_WRITE_COMPRESSED_TEXT_SUPPORTED macro.
+  Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03).
+  Optimize the zlib CMF byte in non-IDAT compressed chunks
+
+Version 1.5.3beta03 [April 16, 2011]
+  Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
+    snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
+    than __STDC__ (John Bowler).
+  Removed the PNG_PTR_NORETURN attribute because it too dangerous. It tells
+    the compiler that a user supplied callback (the error handler) does not
+    return, yet there is no guarantee in practice that the application code
+    will correctly implement the error handler because the compiler only
+    issues a warning if there is a mistake (John Bowler).
+  Removed the no-longer-used PNG_DEPSTRUCT macro.
+  Updated the zlib version to 1.2.5 in the VStudio project.
+  Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
+    pngwutil.c (John Bowler).
+  Fixed bug with stripping the filler or alpha channel when writing, that
+    was introduced in libpng-1.5.2beta01 (bug report by Andrew Church).
+
+Version 1.5.3beta04 [April 27, 2011]
+  Updated pngtest.png with the new zlib CMF optimization.
+  Cleaned up conditional compilation code and of background/gamma handling
+    Internal changes only except a new option to avoid compiling the
+    png_build_grayscale_palette API (which is not used at all internally.)
+    The main change is to move the transform tests (READ_TRANSFORMS,
+    WRITE_TRANSFORMS) up one level to the caller of the APIs.  This avoids
+    calls to spurious functions if all transforms are disabled and slightly
+    simplifies those functions.  Pngvalid modified to handle this.
+    A minor change is to stop the strip_16 and expand_16 interfaces from
+    disabling each other; this allows the future alpha premultiplication
+    code to use 16-bit intermediate values while still producing 8-bit output.
+    png_do_background and png_do_gamma have been simplified to take a single
+    pointer to the png_struct rather than pointers to every item required
+    from the png_struct. This makes no practical difference to the internal
+    code.
+  A serious bug in the pngvalid internal routine 'standard_display_init' has
+    been fixed - this failed to initialize the red channel and accidentally
+    initialized the alpha channel twice.
+  Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
+    avoid a possible clash with the png_jmpbuf macro on some platforms.
+
+Version 1.5.3beta05 [May 6, 2011]
+  Added the "_POSIX_SOURCE" feature test macro to ensure libpng sees the
+    correct API. _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and
+    pngvalid.c to ensure that POSIX conformant systems disable non-POSIX APIs.
+  Removed png_snprintf and added formatted warning messages.  This change adds
+    internal APIs to allow png_warning messages to have parameters without
+    requiring the host OS to implement snprintf.  As a side effect the
+    dependency of the tIME-supporting RFC1132 code on stdio is removed and
+    PNG_NO_WARNINGS does actually work now.
+  Pass "" instead of '\0' to png_default_error() in png_err().  This mistake
+    was introduced in libpng-1.2.20beta01.  This fixes CVE-2011-2691.
+  Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
+    optimization configurable.
+  IDAT compression failed if preceded by a compressed text chunk (bug
+    introduced in libpng-1.5.3beta01-02).  This was because the attempt to
+    reset the zlib stream in png_write_IDAT happened after the first IDAT
+    chunk had been deflated - much too late.  In this change internal
+    functions were added to claim/release the z_stream and, hopefully, make
+    the code more robust.  Also deflateEnd checking is added - previously
+    libpng would ignore an error at the end of the stream.
+
+Version 1.5.3beta06 [May 8, 2011]
+  Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
+  Implemented premultiplied alpha support: png_set_alpha_mode API
+
+Version 1.5.3beta07 [May 11, 2011]
+  Added expand_16 support to the high level interface.
+  Added named value and 'flag' gamma support to png_set_gamma.  Made a minor
+    change from the previous (unreleased) ABI/API to hide the exact value used
+    for Macs - it's not a good idea to embed this in the ABI!
+  Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
+    from pngpriv.h to png.h because they must be visible to applications
+    that call png_set_unknown_chunks().
+  Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
+    before IDAT.
+
+Version 1.5.3beta08 [May 16, 2011]
+  Improved "pngvalid --speed" to exclude more of pngvalid from the time.
+  Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
+  The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
+    parameters are supplied by the caller), while in the absence of cHRM
+    sRGB/Rec 709 values are still used.  This introduced a divide-by-zero
+    bug in png_handle_cHRM().
+  The bKGD chunk no longer overwrites the background value set by
+    png_set_background(), allowing the latter to be used before the file
+    header is read. It never performed any useful function to override
+    the default anyway.
+  Added memory overwrite and palette image checks to pngvalid.c
+    Previously palette image code was poorly checked. Since the transformation
+    code has a special palette path in most cases this was a severe weakness.
+  Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
+    expanding an indexed image, always expand to RGBA if transparency is
+    present.
+
+Version 1.5.3beta09 [May 17, 2011]
+  Reversed earlier 1.5.3 change of transformation order; move png_expand_16
+    back where it was.  The change doesn't work because it requires 16-bit
+    gamma tables when the code only generates 8-bit ones.  This fails
+    silently; the libpng code just doesn't do any gamma correction.  Moving
+    the tests back leaves the old, inaccurate, 8-bit gamma calculations, but
+    these are clearly better than none!
+
+Version 1.5.3beta10 [May 20, 2011]
+
+  png_set_background() and png_expand_16() did not work together correctly.
+    This problem is present in 1.5.2; if png_set_background is called with
+    need_expand false and the matching 16 bit color libpng erroneously just
+    treats it as an 8-bit color because of where png_do_expand_16 is in the
+    transform list.  This simple fix reduces the supplied colour to 8-bits,
+    so it gets smashed, but this is better than the current behavior.
+  Added tests for expand16, more fixes for palette image tests to pngvalid.
+    Corrects the code for palette image tests and disables attempts to
+    validate palette colors.
+
+Version 1.5.3rc01 [June 3, 2011]
+  No changes.
+
+Version 1.5.3rc02 [June 8, 2011]
+  Fixed uninitialized memory read in png_format_buffer() (Bug report by
+    Frank Busse, CVE-2011-2501, related to CVE-2004-0421).
+
+Version 1.5.3beta11 [June 11, 2011]
+  Fixed png_handle_sCAL which is broken in 1.5. This fixes CVE 2011-2692.
+  Added sCAL to pngtest.png
+  Revised documentation about png_set_user_limits() to say that it also affects
+    png writing.
+  Revised handling of png_set_user_limits() so that it can increase the
+    limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only
+    reduce it.
+  Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is
+    wrong (high by one) 25% of the time. Dividing by 257 with rounding is
+    wrong in 128 out of 65536 cases. Getting the right answer all the time
+    without division is easy.
+  Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro.
+  Added projects/owatcom, an IDE project for OpenWatcom to replace
+    scripts/makefile.watcom.  This project works with OpenWatcom 1.9. The
+    IDE autogenerates appropriate makefiles (libpng.mk) for batch processing.
+    The project is configurable, unlike the Visual Studio project, so long
+    as the developer has an awk.
+  Changed png_set_gAMA to limit the gamma value range so that the inverse
+    of the stored value cannot overflow the fixed point representation,
+    and changed other things OpenWatcom warns about.
+  Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows
+    pngvalid to build when ALPHA_MODE is not supported, which is required if
+    it is to build on libpng 1.4.
+  Removed string/memory macros that are no longer used and are not
+    necessarily fully supportable, particularly png_strncpy and png_snprintf.
+  Added log option to pngvalid.c and attempted to improve gamma messages.
+
+Version 1.5.3 [omitted]
+  People found the presence of a beta release following an rc release
+    to be confusing; therefore we bump the version to libpng-1.5.4beta01
+    and there will be no libpng-1.5.3 release.
+
+Version 1.5.4beta01 [June 14, 2011]
+  Made it possible to undefine PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+    to get the same (inaccurate) output as libpng-1.5.2 and earlier.
+  Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE
+    outside of an unknown-chunk block in png.h because they are also
+    needed for other uses.
+
+Version 1.5.4beta02 [June 14, 2011]
+  Fixed and clarified LEGACY 16-to-8 scaling code.
+  Added png_set_chop_16() API, to match inaccurate results from previous
+    libpng versions.
+  Removed the ACCURATE and LEGACY options (they are no longer useable)
+  Use the old scaling method for background if png_set_chop_16() was
+    called.
+  Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED
+
+Version 1.5.4beta03 [June 15, 2011]
+  Fixed a problem in png_do_expand_palette() exposed by optimization in
+    1.5.3beta06
+  Also removed a spurious and confusing "trans" member ("trans") from png_info.
+  The palette expand optimization prevented expansion to an intermediate RGBA
+    form if tRNS was present but alpha was marked to be stripped; this exposed
+    a check for tRNS in png_do_expand_palette() which is inconsistent with the
+    code elsewhere in libpng.
+  Correction to the expand_16 code; removed extra instance of
+    png_set_scale_16_to_8 from pngpriv.h
+
+Version 1.5.4beta04 [June 16, 2011]
+  Added a missing "#ifdef PNG_READ_BACKGROUND_SUPPORTED/#endif" in pngrtran.c
+  Added PNG_TRANSFORM_CHOP_16 to the high-level read transforms.
+  Made PNG_READ_16_TO_8_ACCURATE_SCALE configurable again.  If this is
+    not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built.
+  Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8
+
+Version 1.5.4beta05 [June 16, 2011]
+  Renamed png_set_strip_16() to png_set_scale_16() and renamed
+    png_set_chop_16() to png_set_strip(16) in an attempt to minimize the
+    behavior changes between libpng14 and libpng15.
+
+Version 1.5.4beta06 [June 18, 2011]
+  Fixed new bug that was causing both strip_16 and scale_16 to be applied.
+
+Version 1.5.4beta07 [June 19, 2011]
+  Fixed pngvalid, simplified macros, added checking for 0 in sCAL.
+    The ACCURATE scale macro is no longer defined in 1.5 - call the
+    png_scale_16_to_8 API.  Made sure that PNG_READ_16_TO_8 is still defined
+    if the png_strip_16_to_8 API is present.  png_check_fp_number now
+    maintains some state so that positive, negative and zero values are
+    identified.  sCAL uses these to be strictly spec conformant.
+
+Version 1.5.4beta08 [June 23, 2011]
+  Fixed pngvalid if ACCURATE_SCALE is defined.
+  Updated scripts/pnglibconf.h.prebuilt.
+
+Version 1.5.4rc01 [June 30, 2011]
+  Define PNG_ALLOCATED to "restrict" only if MSC_VER >= 1400.
+
+Version 1.5.4 [July 7, 2011]
+  No changes.
+
+Version 1.5.5beta01 [July 13, 2011]
+  Fixed some typos and made other minor changes in the manual.
+  Updated contrib/pngminus/makefile.std (Samuli Souminen)
+
+Version 1.5.5beta02 [July 14, 2011]
+  Revised Makefile.am and Makefile.in to look in the right directory for
+    pnglibconf.h.prebuilt
+
+Version 1.5.5beta03 [July 27, 2011]
+  Enabled compilation with g++ compiler.  This compiler does not recognize
+    the file extension, so it always compiles with C++ rules.  Made minor
+    changes to pngrutil.c to cast results where C++ expects it but C does not.
+  Minor editing of libpng.3 and libpng-manual.txt.
+
+Version 1.5.5beta04 [July 29, 2011]
+  Revised CMakeLists.txt (Clifford Yapp)
+  Updated commentary about the png_rgb_to_gray() default coefficients
+    in the manual and in pngrtran.c
+
+Version 1.5.5beta05 [August 17, 2011]
+  Prevent unexpected API exports from non-libpng DLLs on Windows.  The "_DLL"
+    is removed from the test of whether a DLL is being built (this erroneously
+    caused the libpng APIs to be marked as DLL exports in static builds under
+    Microsoft Visual Studio).  Almost all of the libpng building configuration
+    is moved from pngconf.h to pngpriv.h, but PNG_DLL_EXPORT remains in
+    pngconf.h, though, so that it is colocated with the import definition (it
+    is no longer used anywhere in the installed headers).  The VStudio project
+    definitions have been cleaned up: "_USRDLL" has been removed from the
+    static library builds (this was incorrect), and PNG_USE_DLL has been added
+    to pngvalid to test the functionality (pngtest does not supply it,
+    deliberately).  The spurious "_EXPORTS" has been removed from the
+    libpng build (all these errors were a result of copy/paste between project
+    configurations.)
+  Added new types and internal functions for CIE RGB end point handling to
+    pngpriv.h (functions yet to be implemented).
+
+Version 1.5.5beta06 [August 26, 2011]
+  Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set in CMakeLists.txt
+    (Clifford Yap)
+  Fixes to rgb_to_gray and cHRM XYZ APIs (John Bowler):
+    The rgb_to_gray code had errors when combined with gamma correction.
+    Some pixels were treated as true grey when they weren't and such pixels
+    and true grey ones were not gamma corrected (the original value of the
+    red component was used instead).  APIs to get and set cHRM using color
+    space end points have been added and the rgb_to_gray code that defaults
+    based on cHRM, and the divide-by-zero bug in png_handle_cHRM (CERT
+    VU#477046, CVE-2011-3328, introduced in 1.5.4) have been corrected.
+  A considerable number of tests has been added to pngvalid for the
+    rgb_to_gray transform.
+  Arithmetic errors in rgb_to_gray whereby the calculated gray value was
+    truncated to the bit depth rather than rounded have been fixed except in
+    the 8-bit non-gamma-corrected case (where consistency seems more important
+    than correctness.)  The code still has considerable inaccuracies in the
+    8-bit case because 8-bit linear arithmetic is used.
+
+Version 1.5.5beta07 [September 7, 2011]
+  Added "$(ARCH)" option to makefile.darwin
+  Added SunOS support to configure.ac and Makefile.am
+  Changed png_chunk_benign_error() to png_warning() in png.c, in
+    png_XYZ_from_xy_checked().
+
+Version 1.5.5beta08 [September 10, 2011]
+  Fixed 64-bit compilation errors (gcc). The errors fixed relate
+    to conditions where types that are 32 bits in the GCC 32-bit
+    world (uLong and png_size_t) become 64 bits in the 64-bit
+    world.  This produces potential truncation errors which the
+    compiler correctly flags.
+  Relocated new HAVE_SOLARIS_LD definition in configure.ac
+  Constant changes for 64-bit compatibility (removal of L suffixes). The
+    16-bit cases still use "L" as we don't have a 16-bit test system.
+
+Version 1.5.5rc01 [September 15, 2011]
+  Removed "L" suffixes in pngpriv.h
+
+Version 1.5.5 [September 22, 2011]
+  No changes.
+
+Version 1.5.6beta01 [September 22, 2011]
+  Fixed some 64-bit type conversion warnings in pngrtran.c
+  Moved row_info from png_struct to a local variable.
+  The various interlace mask arrays have been made into arrays of
+    bytes and made PNG_CONST and static (previously some arrays were
+    marked PNG_CONST and some weren't).
+  Additional checks have been added to the transform code to validate the
+    pixel depths after the transforms on both read and write.
+  Removed some redundant code from pngwrite.c, in png_destroy_write_struct().
+  Changed chunk reading/writing code to use png_uint_32 instead of png_byte[4].
+    This removes the need to allocate temporary strings for chunk names on
+    the stack in the read/write code.  Unknown chunk handling still uses the
+    string form because this is exposed in the API.
+
+Version 1.5.6beta02 [September 26, 2011]
+  Added a note in the manual the png_read_update_info() must be called only
+    once with a particular info_ptr.
+  Fixed a typo in the definition of the new PNG_STRING_FROM_CHUNK(s,c) macro.
+
+Version 1.5.6beta03 [September 28, 2011]
+  Revised test-pngtest.sh to report FAIL when pngtest fails.
+  Added "--strict" option to pngtest, to report FAIL when the failure is
+    only because the resulting valid files are different.
+  Revised CMakeLists.txt to work with mingw and removed some material from
+    CMakeLists.txt that is no longer useful in libpng-1.5.
+
+Version 1.5.6beta04 [October 5, 2011]
+  Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")."
+
+Version 1.5.6beta05 [October 12, 2011]
+  Speed up png_combine_row() for interlaced images. This reduces the generality
+    of the code, allowing it to be optimized for Adam7 interlace.  The masks
+    passed to png_combine_row() are now generated internally, avoiding
+    some code duplication and localizing the interlace handling somewhat.
+  Align png_struct::row_buf - previously it was always unaligned, caused by
+    a bug in the code that attempted to align it; the code needs to subtract
+    one from the pointer to take account of the filter byte prepended to
+    each row.
+  Optimized png_combine_row() when rows are aligned. This gains a small
+    percentage for 16-bit and 32-bit pixels in the typical case where the
+    output row buffers are appropriately aligned. The optimization was not
+    previously possible because the png_struct buffer was always misaligned.
+  Fixed bug in png_write_chunk_header() debug print, introduced in 1.5.6beta01.
+
+Version 1.5.6beta06 [October 17, 2011]
+  Removed two redundant tests for uninitialized row.
+  Fixed a relatively harmless memory overwrite in compressed text writing
+    with a 1 byte zlib buffer.
+  Add ability to call png_read_update_info multiple times to pngvalid.c.
+  Fixes for multiple calls to png_read_update_info. These fixes attend to
+    most of the errors revealed in pngvalid, however doing the gamma work
+    twice results in inaccuracies that can't be easily fixed.  There is now
+    a warning in the code if this is going to happen.
+  Turned on multiple png_read_update_info in pngvalid transform tests.
+  Prevent libpng from overwriting unused bits at the end of the image when
+    it is not byte aligned, while reading. Prior to libpng-1.5.6 libpng would
+    overwrite the partial byte at the end of each row if the row width was not
+    an exact multiple of 8 bits and the image is not interlaced.
+
+Version 1.5.6beta07 [October 21, 2011]
+  Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row
+    (Mans Rullgard).
+
+Version 1.5.6rc01 [October 26, 2011]
+  Changed misleading "Missing PLTE before cHRM" warning to "Out of place cHRM"
+
+Version 1.5.6rc02 [October 27, 2011]
+  Added LSR() macro to defend against buggy compilers that evaluate non-taken
+    code branches and complain about out-of-range shifts.
+
+Version 1.5.6rc03 [October 28, 2011]
+  Renamed the LSR() macro to PNG_LSR() and added PNG_LSL() macro.
+  Fixed compiler warnings with Intel and MSYS compilers. The logical shift
+    fix for Microsoft Visual C is required by other compilers, so this
+    enables that fix for all compilers when using compile-time constants.
+    Under MSYS 'byte' is a name declared in a system header file, so we
+    changed the name of a local variable to avoid the warnings that result.
+  Added #define PNG_ALIGN_TYPE PNG_ALIGN_NONE to contrib/pngminim/*/pngusr.h
+
+Version 1.5.6 [November 3, 2011]
+  No changes.
+
+Version 1.5.7beta01 [November 4, 2011]
+  Added support for ARM processor, when decoding all PNG up-filtered rows
+    and any other-filtered rows with 3 or 4 bytes per pixel (Mans Rullgard).
+  Fixed bug in pngvalid on early allocation failure; fixed type cast in
+    pngmem.c; pngvalid would attempt to call png_error() if the allocation
+    of a png_struct or png_info failed. This would probably have led to a
+    crash.  The pngmem.c implementation of png_malloc() included a cast
+    to png_size_t which would fail on large allocations on 16-bit systems.
+  Fix for the preprocessor of the Intel C compiler. The preprocessor
+    splits adjacent @ signs with a space; this changes the concatenation
+    token from @-@-@ to PNG_JOIN; that should work with all compiler
+    preprocessors.
+  Paeth filter speed improvements from work by Siarhei Siamashka. This
+    changes the 'Paeth' reconstruction function to improve the GCC code
+    generation on x86. The changes are only part of the suggested ones;
+    just the changes that definitely improve speed and remain simple.
+    The changes also slightly increase the clarity of the code.
+
+Version 1.5.7beta02 [November 11, 2011]
+  Check compression_type parameter in png_get_iCCP and remove spurious
+    casts. The compression_type parameter is always assigned to, so must
+    be non-NULL. The cast of the profile length potentially truncated the
+    value unnecessarily on a 16-bit int system, so the cast of the (byte)
+    compression type to (int) is specified by ANSI-C anyway.
+  Fixed FP division by zero in pngvalid.c; the 'test_pixel' code left
+    the sBIT fields in the test pixel as 0, which resulted in a floating
+    point division by zero which was irrelevant but causes systems where
+    FP exceptions cause a crash. Added code to pngvalid to turn on FP
+    exceptions if the appropriate glibc support is there to ensure this is
+    tested in the future.
+  Updated scripts/pnglibconf.mak and scripts/makefile.std to handle the
+    new PNG_JOIN macro.
+  Added versioning to pnglibconf.h comments.
+  Simplified read/write API initial version; basic read/write tested on
+    a variety of images, limited documentation (in the header file.)
+  Installed more accurate linear to sRGB conversion tables. The slightly
+    modified tables reduce the number of 16-bit values that
+    convert to an off-by-one 8-bit value.  The "makesRGB.c" code that was used
+    to generate the tables is now in a contrib/sRGBtables sub-directory.
+
+Version 1.5.7beta03 [November 17, 2011]
+  Removed PNG_CONST from the sRGB table declarations in pngpriv.h and png.c
+  Added run-time detection of NEON support.
+  Added contrib/libtests; includes simplified API test and timing test and
+    a color conversion utility for rapid checking of failed 'pngstest' results.
+  Multiple transform bug fixes plus a work-round for double gamma correction.
+    libpng does not support more than one transform that requires linear data
+    at once - if this is tried typically the results is double gamma
+    correction. Since the simplified APIs can need rgb to gray combined with
+    a compose operation it is necessary to do one of these outside the main
+    libpng transform code. This check-in also contains fixes to various bugs
+    in the simplified APIs themselves and to some bugs in compose and rgb to
+    gray (on palette) itself.
+  Fixes for C++ compilation using g++ When libpng source is compiled
+    using g++. The compiler imposes C++ rules on the C source; thus it
+    is desirable to make the source work with either C or C++ rules
+    without throwing away useful error information.  This change adds
+    png_voidcast to allow C semantic (void*) cases or the corresponding
+    C++ static_cast operation, as appropriate.
+  Added --noexecstack to assembler file compilation. GCC does not set
+    this on assembler compilation, even though it does on C compilation.
+    This creates security issues if assembler code is enabled; the
+    work-around is to set it by default in the flags for $(CCAS)
+  Work around compilers that don't support declaration of const data. Some
+    compilers fault 'extern const' data declarations (because the data is
+    not initialized); this turns on const-ness only for compilers where
+    this is known to work.
+
+Version 1.5.7beta04 [November 17, 2011]
+  Since the gcc driver does not recognize the --noexecstack flag, we must
+    use the -Wa prefix to have it passed through to the assembler.
+    Also removed a duplicate setting of this flag.
+  Added files that were omitted from the libpng-1.5.7beta03 zip distribution.
+
+Version 1.5.7beta05 [November 25, 2011]
+  Removed "zTXt" from warning in generic chunk decompression function.
+  Validate time settings passed to png_set_tIME() and png_convert_to_rfc1123()
+    (Frank Busse). Note: This prevented CVE-2015-7981 from affecting
+    libpng-1.5.7 and later.
+  Added MINGW support to CMakeLists.txt
+  Reject invalid compression flag or method when reading the iTXt chunk.
+  Backed out 'simplified' API changes. The API seems too complex and there
+    is a lack of consensus or enthusiasm for the proposals.  The API also
+    reveals significant bugs inside libpng (double gamma correction and the
+    known bug of being unable to retrieve a corrected palette). It seems
+    better to wait until the bugs, at least, are corrected.
+  Moved pngvalid.c into contrib/libtests
+  Rebuilt Makefile.in, configure, etc., with autoconf-2.68
+
+Version 1.5.7rc01 [December 1, 2011]
+  Replaced an "#if" with "#ifdef" in pngrtran.c
+  Revised #if PNG_DO_BC block in png.c (use #ifdef and add #else)
+
+Version 1.5.7rc02 [December 5, 2011]
+  Revised project files and contrib/pngvalid/pngvalid.c to account for
+    the relocation of pngvalid into contrib/libtests.
+  Revised pngconf.h to use " __declspec(restrict)" only when MSC_VER >= 1400,
+    as in libpng-1.5.4.
+  Put CRLF line endings in the owatcom project files.
+
+Version 1.5.7rc03 [December 7, 2011]
+  Updated CMakeLists.txt to account for the relocation of pngvalid.c
+
+Version 1.5.7 [December 15, 2011]
+  Minor fixes to pngvalid.c for gcc 4.6.2 compatibility to remove warnings
+    reported by earlier versions.
+  Fixed minor memset/sizeof errors in pngvalid.c.
+
+Version 1.6.0beta01 [December 15, 2011]
+  Removed machine-generated configure files from the GIT repository (they will
+    continue to appear in the tarball distributions and in the libpng15 and
+    earlier GIT branches).
+  Restored the new 'simplified' API, which was started in libpng-1.5.7beta02
+    but later deleted from libpng-1.5.7beta05.
+  Added example programs for the new 'simplified' API.
+  Added ANSI-C (C90) headers and require them, and take advantage of the
+    change. Also fixed some of the projects/* and contrib/* files that needed
+    updates for libpng16 and the move of pngvalid.c.
+    With this change the required ANSI-C header files are assumed to exist: the
+    implementation must provide float.h, limits.h, stdarg.h and stddef.h and
+    libpng relies on limits.h and stddef.h existing and behaving as defined
+    (the other two required headers aren't used).  Non-ANSI systems that don't
+    have stddef.h or limits.h will have to provide an appropriate fake
+    containing the relevant types and #defines.
+  Dropped support for 16-bit platforms. The use of FAR/far has been eliminated
+    and the definition of png_alloc_size_t is now controlled by a flag so
+    that 'small size_t' systems can select it if necessary.  Libpng 1.6 may
+    not currently work on such systems -- it seems likely that it will
+    ask 'malloc' for more than 65535 bytes with any image that has a
+    sufficiently large row size (rather than simply failing to read such
+    images).
+  New tools directory containing tools used to generate libpng code.
+  Fixed race conditions in parallel make builds. With higher degrees of
+    parallelism during 'make' the use of the same temporary file names such
+    as 'dfn*' can result in a race where a temporary file from one arm of the
+    build is deleted or overwritten in another arm.  This changes the
+    temporary files for suffix rules to always use $* and ensures that the
+    non-suffix rules use unique file names.
+
+Version 1.6.0beta02 [December 21, 2011]
+  Correct configure builds where build and source directories are separate.
+    The include path of 'config.h' was erroneously made relative in pngvalid.c
+    in libpng 1.5.7.
+
+Version 1.6.0beta03 [December 22, 2011]
+  Start-up code size improvements, error handler flexibility. These changes
+    alter how the tricky allocation of the initial png_struct and png_info
+    structures are handled. png_info is now handled in pretty much the same
+    way as everything else, except that the allocations handle NULL return
+    silently.  png_struct is changed in a similar way on allocation and on
+    deallocation a 'safety' error handler is put in place (which should never
+    be required).  The error handler itself is changed to permit mismatches
+    in the application and libpng error buffer size; however, this means a
+    silent change to the API to return the jmp_buf if the size doesn't match
+    the size from the libpng compilation; libpng now allocates the memory and
+    this may fail.  Overall these changes result in slight code size
+    reductions; however, this is a reduction in code that is always executed
+    so is particularly valuable.  Overall on a 64-bit system the libpng DLL
+    decreases in code size by 1733 bytes.  pngerror.o increases in size by
+    about 465 bytes because of the new functionality.
+  Added png_convert_to_rfc1123_buffer() and deprecated png_convert_to_rfc1123()
+    to avoid including a spurious buffer in the png_struct.
+
+Version 1.6.0beta04 [December 30, 2011]
+  Regenerated configure scripts with automake-1.11.2
+  Eliminated png_info_destroy(). It is now used only in png.c and only calls
+    one other internal function and memset().
+  Enabled png_get_sCAL_fixed() if floating point APIs are enabled. Previously
+    it was disabled whenever internal fixed point arithmetic was selected,
+    which meant it didn't exist even on systems where FP was available but not
+    preferred.
+  Added pngvalid.c compile time checks for const APIs.
+  Implemented 'restrict' for png_info and png_struct. Because of the way
+    libpng works both png_info and png_struct are always accessed via a
+    single pointer.  This means adding C99 'restrict' to the pointer gives
+    the compiler some opportunity to optimize the code.  This change allows
+    that.
+  Moved AC_MSG_CHECKING([if libraries can be versioned]) later to the proper
+    location in configure.ac (Gilles Espinasse).
+  Changed png_memcpy to C assignment where appropriate. Changed all those
+    uses of png_memcpy that were doing a simple assignment to assignments
+    (all those cases where the thing being copied is a non-array C L-value).
+  Added some error checking to png_set_*() routines.
+  Removed the reference to the non-exported function png_memcpy() from
+    example.c.
+  Fixed the Visual C 64-bit build - it requires jmp_buf to be aligned, but
+    it had become misaligned.
+  Revised contrib/pngminus/pnm2png.c to avoid warnings when png_uint_32
+    and unsigned long are of different sizes.
+
+Version 1.6.0beta05 [January 15, 2012]
+  Updated manual with description of the simplified API (copied from png.h)
+  Fix bug in pngerror.c: some long warnings were being improperly truncated
+    (CVE-2011-3464, bug introduced in libpng-1.5.3beta05).
+
+Version 1.6.0beta06 [January 24, 2012]
+  Added palette support to the simplified APIs. This commit
+    changes some of the macro definitions in png.h, app code
+    may need corresponding changes.
+  Increased the formatted warning buffer to 192 bytes.
+  Added color-map support to simplified API. This is an initial version for
+    review; the documentation has not yet been updated.
+  Fixed Min/GW uninstall to remove libpng.dll.a
+
+Version 1.6.0beta07 [January 28, 2012]
+  Eliminated Intel icc/icl compiler warnings. The Intel (GCC derived)
+    compiler issues slightly different warnings from those issued by the
+    current versions of GCC. This eliminates those warnings by
+    adding/removing casts and small code rewrites.
+  Updated configure.ac from autoupdate: added --enable-werror option.
+    Also some layout regularization and removal of introduced tab characters
+    (replaced with 3-character indentation).  Obsolete macros identified by
+    autoupdate have been removed; the replacements are all in 2.59 so
+    the pre-req hasn't been changed.  --enable-werror checks for support
+    for -Werror (or the given argument) in the compiler.  This mimics the
+    gcc configure option by allowing -Werror to be turned on safely; without
+    the option the tests written in configure itself fail compilation because
+    they cause compiler warnings.
+  Rewrote autogen.sh to run autoreconf instead of running tools one-by-one.
+  Conditionalize the install rules for MINGW and CYGWIN in CMakeLists.txt and
+    set CMAKE_LIBRARY_OUTPUT_DIRECTORY to "lib" on all platforms (C. Yapp).
+  Freeze libtool files in the 'scripts' directory. This version of autogen.sh
+    attempts to dissuade people from running it when it is not, or should not,
+    be necessary.  In fact, autogen.sh does not work when run in a libpng
+    directory extracted from a tar distribution anymore. You must run it in
+    a GIT clone instead.
+  Added two images to contrib/pngsuite (1-bit and 2-bit transparent grayscale),
+    and renamed three whose names were inconsistent with those in
+    pngsuite/README.txt.
+
+Version 1.6.0beta08 [February 1, 2012]
+  Fixed Image::colormap misalignment in pngstest.c
+  Check libtool/libtoolize version number (2.4.2) in configure.ac
+  Divide test-pngstest.sh into separate pngstest runs for basic and
+    transparent images.
+  Moved automake options to AM_INIT_AUTOMAKE in configure.ac
+  Added color-tests, silent-rules (Not yet implemented in Makefile.am) and
+    version checking to configure.ac
+  Improved pngstest speed by not doing redundant tests and add const to
+    the background parameter of png_image_finish_read. The --background
+    option is now done automagically only when required, so that command-line
+    option no longer exists.
+  Cleaned up pngpriv.h to consistently declare all functions and data.
+    Also eliminated PNG_CONST_DATA, which is apparently not needed but we
+    can't be sure until it is gone.
+  Added symbol prefixing that allows all the libpng external symbols
+    to be prefixed (suggested by Reuben Hawkins).
+  Updated "ftbb*.png" list in the owatcom and vstudio projects.
+  Fixed 'prefix' builds on clean systems. The generation of pngprefix.h
+    should not require itself.
+  Updated INSTALL to explain that autogen.sh must be run in a GIT clone,
+    not in a libpng directory extracted from a tar distribution.
+
+Version 1.6.0beta09 [February 1, 2012]
+  Reverted the prebuilt configure files to libpng-1.6.0beta05 condition.
+
+Version 1.6.0beta10 [February 3, 2012]
+  Added Z_SOLO for zlib-1.2.6+ and correct pngstest tests
+  Updated list of test images in CMakeLists.txt
+  Updated the prebuilt configure files to current condition.
+  Revised INSTALL information about autogen.sh; it works in tar distributions.
+
+Version 1.6.0beta11 [February 16, 2012]
+  Fix character count in pngstest command in projects/owatcom/pngstest.tgt
+  Revised test-pngstest.sh to report PASS/FAIL for each image.
+  Updated documentation about the simplified API.
+  Corrected estimate of error in libpng png_set_rgb_to_gray API.  The API is
+    extremely inaccurate for sRGB conversions because it uses an 8-bit
+    intermediate linear value and it does not use the sRGB transform, so it
+    suffers from the known instability in gamma transforms for values close
+    to 0 (see Poynton).  The net result is that the calculation has a maximum
+    error of 14.99/255; 0.5/255^(1/2.2).  pngstest now uses 15 for the
+    permitted 8-bit error. This may still not be enough because of arithmetic
+    error.
+  Removed some unused arrays (with #ifdef) from png_read_push_finish_row().
+  Fixed a memory overwrite bug in simplified read of RGB PNG with
+    non-linear gamma Also bugs in the error checking in pngread.c and changed
+    quite a lot of the checks in pngstest.c to be correct; either correctly
+    written or not over-optimistic.  The pngstest changes are insufficient to
+    allow all possible RGB transforms to be passed; pngstest cmppixel needs
+    to be rewritten to make it clearer which errors it allows and then changed
+    to permit known inaccuracies.
+  Removed tests for no-longer-used *_EMPTY_PLTE_SUPPORTED from pngstruct.h
+  Fixed fixed/float API export conditionals. 1) If FIXED_POINT or
+    FLOATING_POINT options were switched off, png.h ended up with lone ';'
+    characters.  This is not valid ANSI-C outside a function.  The ';'
+    characters have been moved inside the definition of PNG_FP_EXPORT and
+    PNG_FIXED_EXPORT. 2) If either option was switched off, the declaration
+    of the corresponding functions were completely omitted, even though some
+    of them are still used internally.  The result is still valid, but
+    produces warnings from gcc with some warning options (including -Wall). The
+    fix is to cause png.h to declare the functions with PNG_INTERNAL_FUNCTION
+    when png.h is included from pngpriv.h.
+  Check for invalid palette index while reading paletted PNG.  When one is
+    found, issue a warning and increase png_ptr->num_palette accordingly.
+    Apps are responsible for checking to see if that happened.
+
+Version 1.6.0beta12 [February 18, 2012]
+  Do not increase num_palette on invalid_index.
+  Relocated check for invalid palette index to pngrtran.c, after unpacking
+    the sub-8-bit pixels.
+  Fixed CVE-2011-3026 buffer overrun bug.  This bug was introduced when
+    iCCP chunk support was added at libpng-1.0.6. Deal more correctly with the
+    test on iCCP chunk length. Also removed spurious casts that may hide
+    problems on 16-bit systems.
+
+Version 1.6.0beta13 [February 24, 2012]
+  Eliminated redundant png_push_read_tEXt|zTXt|iTXt|unknown code from
+    pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
+    now that png_ptr->buffer is inaccessible to applications, the special
+    handling is no longer useful.
+  Added PNG_SAFE_LIMITS feature to pnglibconf.dfa, pngpriv.h, and new
+    pngusr.dfa to reset the user limits to safe ones if PNG_SAFE_LIMITS is
+    defined.  To enable, use "CPPFLAGS=-DPNG_SAFE_LIMITS_SUPPORTED=1" on the
+    configure command or put #define PNG_SAFE_LIMITS_SUPPORTED in
+    pnglibconf.h.prebuilt and pnglibconf.h.
+
+Version 1.6.0beta14 [February 27, 2012]
+  Added information about the new limits in the manual.
+  Updated Makefile.in
+
+Version 1.6.0beta15 [March 2, 2012]
+  Removed unused "current_text" members of png_struct and the png_free()
+    of png_ptr->current_text from pngread.c
+  Rewrote pngstest.c for substantial speed improvement.
+  Fixed transparent pixel and 16-bit rgb tests in pngstest and removed a
+    spurious check in pngwrite.c
+  Added PNG_IMAGE_FLAG_FAST for the benefit of applications that store
+    intermediate files, or intermediate in-memory data, while processing
+    image data with the simplified API.  The option makes the files larger
+    but faster to write and read.  pngstest now uses this by default; this
+    can be disabled with the --slow option.
+  Improved pngstest fine tuning of error numbers, new test file generator.
+    The generator generates images that test the full range of sample values,
+    allow the error numbers in pngstest to be tuned and checked.  makepng
+    also allows generation of images with extra chunks, although this is
+    still work-in-progress.
+  Added check for invalid palette index while reading.
+  Fixed some bugs in ICC profile writing. The code should now accept
+    all potentially valid ICC profiles and reject obviously invalid ones.
+    It now uses png_error() to do so rather than casually writing a PNG
+    without the necessary color data.
+  Removed whitespace from the end of lines in all source files and scripts.
+
+Version 1.6.0beta16 [March 6, 2012]
+  Relocated palette-index checking function from pngrutil.c to pngtrans.c
+  Added palette-index checking while writing.
+  Changed png_inflate() and calling routines to avoid overflow problems.
+    This is an intermediate check-in that solves the immediate problems and
+    introduces one performance improvement (avoiding a copy via png_ptr->zbuf.)
+    Further changes will be made to make ICC profile handling more secure.
+  Fixed build warnings (MSVC, GCC, GCC v3). Cygwin GCC with default options
+    declares 'index' as a global, causing a warning if it is used as a local
+    variable.  GCC 64-bit warns about assigning a (size_t) (unsigned 64-bit)
+    to an (int) (signed 32-bit).  MSVC, however, warns about using the
+    unary '-' operator on an unsigned value (even though it is well defined
+    by ANSI-C to be ~x+1).  The padding calculation was changed to use a
+    different method.  Removed the tests on png_ptr->pass.
+  Added contrib/libtests/tarith.c to test internal arithmetic functions from
+    png.c. This is a libpng maintainer program used to validate changes to the
+    internal arithmetic functions.
+  Made read 'inflate' handling like write 'deflate' handling. The read
+    code now claims and releases png_ptr->zstream, like the write code.
+    The bug whereby the progressive reader failed to release the zstream
+    is now fixed, all initialization is delayed, and the code checks for
+    changed parameters on deflate rather than always calling
+    deflatedEnd/deflateInit.
+  Validate the zTXt strings in pngvalid.
+  Added code to validate the windowBits value passed to deflateInit2().
+    If the call to deflateInit2() is wrong a png_warning will be issued
+    (in fact this is harmless, but the PNG data produced may be sub-optimal).
+
+Version 1.6.0beta17 [March 10, 2012]
+  Fixed PNG_LIBPNG_BUILD_BASE_TYPE definition.
+  Reject all iCCP chunks after the first, even if the first one is invalid.
+  Deflate/inflate was reworked to move common zlib calls into single
+    functions [rw]util.c.  A new shared keyword check routine was also added
+    and the 'zbuf' is no longer allocated on progressive read.  It is now
+    possible to call png_inflate() incrementally.  A warning is no longer
+    issued if the language tag or translated keyword in the iTXt chunk
+    has zero length.
+  If benign errors are disabled use maximum window on ancillary inflate.
+    This works round a bug introduced in 1.5.4 where compressed ancillary
+    chunks could end up with a too-small windowBits value in the deflate
+    header.
+
+Version 1.6.0beta18 [March 16, 2012]
+  Issue a png_benign_error() instead of png_warning() about bad palette index.
+  In pngtest, treat benign errors as errors if "-strict" is present.
+  Fixed an off-by-one error in the palette index checking function.
+  Fixed a compiler warning under Cygwin (Windows-7, 32-bit system)
+  Revised example.c to put text strings in a temporary character array
+    instead of directly assigning string constants to png_textp members.
+    This avoids compiler warnings when -Wwrite-strings is enabled.
+  Added output flushing to aid debugging under Visual Studio. Unfortunately
+    this is necessary because the VS2010 output window otherwise simply loses
+    the error messages on error (they weren't flushed to the window before
+    the process exited, apparently!)
+  Added configuration support for benign errors and changed the read
+    default. Also changed some warnings in the iCCP and sRGB handling
+    from to benign errors. Configuration now makes read benign
+    errors warnings and write benign errors to errors by default (thus
+    changing the behavior on read).  The simplified API always forces
+    read benign errors to warnings (regardless of the system default, unless
+    this is disabled in which case the simplified API can't be built.)
+
+Version 1.6.0beta19 [March 18, 2012]
+  Work around for duplicate row start calls; added warning messages.
+    This turns on PNG_FLAG_DETECT_UNINITIALIZED to detect app code that
+    fails to call one of the 'start' routines (not enabled in libpng-1.5
+    because it is technically an API change, since it did normally work
+    before.)  It also makes duplicate calls to png_read_start_row (an
+    internal function called at the start of the image read) benign, as
+    they were before changes to use png_inflate_claim. Somehow webkit is
+    causing this to happen; this is probably a mis-feature in the zlib
+    changes so this commit is only a work-round.
+  Removed erroneous setting of DETECT_UNINITIALIZED and added more
+    checks. The code now does a png_error if an attempt is made to do the
+    row initialization twice; this is an application error and it has
+    serious consequences because the transform data in png_struct is
+    changed by each call.
+  Added application error reporting and added chunk names to read
+    benign errors; also added --strict to pngstest - not enabled
+    yet because a warning is produced.
+  Avoid the double gamma correction warning in the simplified API.
+    This allows the --strict option to pass in the pngstest checks
+
+Version 1.6.0beta20 [March 29, 2012]
+  Changed chunk handler warnings into benign errors, incrementally load iCCP
+  Added checksum-icc.c to contrib/tools
+  Prevent PNG_EXPAND+PNG_SHIFT doing the shift twice.
+  Recognize known sRGB ICC profiles while reading; prefer writing the
+    iCCP profile over writing the sRGB chunk, controlled by the
+    PNG_sRGB_PROFILE_CHECKS option.
+  Revised png_set_text_2() to avoid potential memory corruption (fixes
+    CVE-2011-3048, also known as CVE-2012-3425).
+
+Version 1.6.0beta21 [April 27, 2012]
+  Revised scripts/makefile.darwin: use system zlib; remove quotes around
+    architecture list; add missing ppc architecture; add architecture options
+    to shared library link; don't try to create a shared lib based on missing
+    RELEASE variable.
+  Enable png_set_check_for_invalid_index() for both read and write.
+  Removed #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED in pngpriv.h around
+    declaration of png_handle_unknown().
+  Added -lssp_nonshared in a comment in scripts/makefile.freebsd
+    and changed deprecated NOOBJ and NOPROFILE to NO_OBJ and NO_PROFILE.
+
+Version 1.6.0beta22 [May 23, 2012]
+  Removed need for -Wno-cast-align with clang.  clang correctly warns on
+    alignment increasing pointer casts when -Wcast-align is passed. This
+    fixes the cases that clang warns about either by eliminating the
+    casts from png_bytep to png_uint_16p (pngread.c), or, for pngrutil.c
+    where the cast is previously verified or pngstest.c where it is OK, by
+    introducing new png_aligncast macros to do the cast in a way that clang
+    accepts.
+
+Version 1.6.0beta23 [June 6, 2012]
+  Revised CMakeLists.txt to not attempt to make a symlink under mingw.
+  Made fixes for new optimization warnings from gcc 4.7.0. The compiler
+    performs an optimization which is safe; however it then warns about it.
+    Changing the type of 'palette_number' in pngvalid.c removes the warning.
+  Do not depend upon a GCC feature macro being available for use in generating
+    the linker mapfile symbol prefix.
+  Improved performance of new do_check_palette_indexes() function (only
+    update the value when it actually increases, move test for whether
+    the check is wanted out of the function.
+
+Version 1.6.0beta24 [June 7, 2012]
+  Don't check palette indexes if num_palette is 0 (as it can be in MNG files).
+
+Version 1.6.0beta25 [June 16, 2012]
+  Revised png_set_keep_unknown_chunks() so num_chunks < 0 means ignore all
+    unknown chunks and all known chunks except for IHDR, PLTE, tRNS, IDAT,
+    and IEND.  Previously it only meant ignore all unknown chunks, the
+    same as num_chunks == 0. Revised png_image_skip_unused_chunks() to
+    provide a list of chunks to be processed instead of a list of chunks to
+    ignore.  Revised contrib/gregbook/readpng2.c accordingly.
+
+Version 1.6.0beta26 [July 10, 2012]
+  Removed scripts/makefile.cegcc from the *.zip and *.7z distributions; it
+    depends on configure, which is not included in those archives.
+  Moved scripts/chkfmt to contrib/tools.
+  Changed "a+w" to "u+w" in Makefile.in to fix CVE-2012-3386.
+
+Version 1.6.0beta27 [August 11, 2012]
+  Do not compile PNG_DEPRECATED, PNG_ALLOC and PNG_PRIVATE when __GNUC__ < 3.
+  Do not use __restrict when GNUC is <= 3.1
+  Removed references to png_zalloc() and png_zfree() from the manual.
+  Fixed configurations where floating point is completely disabled.  Because
+    of the changes to support symbol prefixing PNG_INTERNAL_FUNCTION declares
+    floating point APIs during libpng builds even if they are completely
+    disabled. This requires the png floating point types (png_double*) to be
+    declared even though the functions are never actually defined.  This
+    change provides a dummy definition so that the declarations work, yet any
+    implementation will fail to compile because of an incomplete type.
+  Re-eliminated the use of strcpy() in pngtest.c.  An unnecessary use of
+    strcpy() was accidentally re-introduced in libpng16; this change replaces
+    it with strncpy().
+  Eliminated use of png_sizeof(); use sizeof() instead.
+  Use a consistent style for (sizeof type) and (sizeof (array))
+  Cleanup of png_set_filler().  This function does very different things on
+    read and write.  In libpng 1.6 the two cases can be distinguished and
+    considerable code cleanup, and extra error checking, is possible.  This
+    makes calls on the write side that have no effect be ignored with a
+    png_app_error(), which can be disabled in the app using
+    png_set_benign_errors(), and removes the spurious use of usr_channels
+    on the read side.
+  Insist on autotools 1.12.1 for git builds because there are security issues
+    with 1.12 and insisting on anything less would allow 1.12 to be used.
+  Removed info_ptr->signature[8] from WRITE-only builds.
+  Add some conditions for compiling png_fixed().  This is a small function
+    but it requires "-lm" on some platforms.
+  Cause pngtest --strict to fail on any warning from libpng (not just errors)
+    and cause it not to fail at the comparison step if libpng lacks support
+    for writing chunks that it reads from the input (currently only implemented
+    for compressed text chunks).
+  Make all three "make check" test programs work without READ or WRITE support.
+    Now "make check" will succeed even if libpng is compiled with -DPNG_NO_READ
+    or -DPNG_NO_WRITE.  The tests performed are reduced, but the basic reading
+    and writing of a PNG file is always tested by one or more of the tests.
+  Consistently use strlen(), memset(), memcpy(), and memcmp() instead of the
+    png_strlen(), png_memset(), png_memcpy(), and png_memcmp() macros.
+  Removed the png_sizeof(), png_strlen(), png_memset(), png_memcpy(), and
+    png_memcmp() macros.
+  Work around gcc 3.x and Microsoft Visual Studio 2010 complaints. Both object
+    to the split initialization of num_chunks.
+
+Version 1.6.0beta28 [August 29, 2012]
+  Unknown handling fixes and clean up. This adds more correct option
+    control of the unknown handling, corrects the pre-existing bug where
+    the per-chunk 'keep' setting is ignored and makes it possible to skip
+    IDAT chunks in the sequential reader (broken in earlier 1.6 versions).
+    There is a new test program, test-unknown.c, which is a work in progress
+    (not currently part of the test suite).  Comments in the header files now
+    explain how the unknown handling works.
+  Allow fine grain control of unknown chunk APIs. This change allows
+    png_set_keep_unknown_chunks() to be turned off if not required and causes
+    both read and write to behave appropriately (on read this is only possible
+    if the user callback is used to handle unknown chunks).  The change
+    also removes the support for storing unknown chunks in the info_struct
+    if the only unknown handling enabled is via the callback, allowing libpng
+    to be configured with callback reading and none of the unnecessary code.
+  Corrected fix for unknown handling in pngtest. This reinstates the
+    libpng handling of unknown chunks other than vpAg and sTER (including
+    unsafe-to-copy chunks which were dropped before) and eliminates the
+    repositioning of vpAg and sTER in pngtest.png by changing pngtest.png
+    (so the chunks are where libpng would put them).
+  Added "tunknown" test and corrected a logic error in png_handle_unknown()
+    when SAVE support is absent.  Moved the shell test scripts for
+    contrib/libtests from the libpng top directory to contrib/libtests.
+    png_handle_unknown() must always read or skip the chunk, if
+    SAVE_UNKNOWN_CHUNKS is turned off *and* the application does not set
+    a user callback an unknown chunk will not be read, leading to a read
+    error, which was revealed by the "tunknown" test.
+  Cleaned up and corrected ICC profile handling.
+    contrib/libtests/makepng: corrected 'rgb' and 'gray' cases.  profile_error
+    messages could be truncated; made a correct buffer size calculation and
+    adjusted pngerror.c appropriately. png_icc_check_* checking improved;
+    changed the functions to receive the correct color type of the PNG on read
+    or write and check that it matches the color space of the profile (despite
+    what the comments said before, there is danger in assuming the app will
+    cope correctly with an RGB profile on a grayscale image and, since it
+    violates the PNG spec, allowing it is certain to produce inconsistent
+    app behavior and might even cause app crashes.) Check that profiles
+    contain the tags needed to process the PNG (tags all required by the ICC
+    spec). Removed unused PNG_STATIC from pngpriv.h.
+
+Version 1.6.0beta29 [September 4, 2012]
+  Fixed the simplified API example programs to add the *colormap parameter
+    to several of he API and improved the error message if the version field
+    is not set.
+  Added contrib/examples/* to the *.zip and *.7z distributions.
+  Updated simplified API synopses and description of the png_image structure
+    in the manual.
+  Made makepng and pngtest produce identical PNGs, add "--relaxed" option
+    to pngtest. The "--relaxed" option turns off the benign errors that are
+    enabled by default in pre-RC builds. makepng can now write ICC profiles
+    where the length has not been extended to a multiple of 4, and pngtest
+    now intercepts all libpng errors, allowing the previously-introduced
+    "--strict test" on no warnings to actually work.
+  Improved ICC profile handling including cHRM chunk generation and fixed
+    Cygwin+MSVC build errors. The ICC profile handling now includes more
+    checking.  Several errors that caused rejection of the profile are now
+    handled with a warning in such a way that the invalid profiles will be
+    read by default in release (but not pre-RC) builds but will not be
+    written by default.  The easy part of handling the cHRM chunk is written,
+    where the ICC profile contains the required data.  The more difficult
+    part plus guessing a gAMA value requires code to pass selected RGB values
+    through the profile.
+
+Version 1.6.0beta30 [October 24, 2012]
+  Changed ICC profile matrix/vector types to not depend on array type rules.
+    By the ANSI-C standard the new types should be identical to the previous
+    versions, and all known versions of gcc tested with the previous versions
+    except for GCC-4.2.1 work with this version.  The change makes the ANSI-C
+    rule that const applied to an array of elements applies instead to the
+    elements in the array moot by explicitly applying const to the base
+    elements of the png_icc_matrix and png_icc_vector types. The accidental
+    (harmless) 'const' previously applied to the parameters of two of the
+    functions have also been removed.
+  Added a work around for GCC 4.2 optimization bug.
+  Marked the broken (bad white point) original HP sRGB profiles correctly and
+    correct comments.
+  Added -DZ_SOLO to contrib/pngminim/*/makefile to work with zlib-1.2.7
+  Use /MDd for vstudio debug builds. Also added pngunkown to the vstudio
+    builds, fixed build errors and corrected a minor exit code error in
+    pngvalid if the 'touch' file name is invalid.
+  Add updated WARNING file to projects/vstudio from libpng 1.5/vstudio
+  Fixed build when using #define PNG_NO_READ_GAMMA in png_do_compose() in
+    pngrtran.c (Domani Hannes).
+
+Version 1.6.0beta31 [November 1, 2012]
+  Undid the erroneous change to vstudio/pngvalid build in libpng-1.6.0beta30.
+  Made pngvalid so that it will build outside the libpng source tree.
+  Made builds -DPNG_NO_READ_GAMMA compile (the unit tests still fail).
+  Made PNG_NO_READ_GAMMA switch off interfaces that depend on READ_GAMMA.
+    Prior to 1.6.0 switching off READ_GAMMA did unpredictable things to the
+    interfaces that use it (specifically, png_do_background in 1.4 would
+    simply display composite for grayscale images but do composition
+    with the incorrect arithmetic for color ones). In 1.6 the semantic
+    of -DPNG_NO_READ_GAMMA is changed to simply disable any interface that
+    depends on it; this obliges people who set it to consider whether they
+    really want it off if they happen to use any of the interfaces in
+    question (typically most users who disable it won't).
+  Fixed GUIDs in projects/vstudio. Some were duplicated or missing,
+    resulting in VS2010 having to update the files.
+  Removed non-working ICC profile support code that was mostly added to
+    libpng-1.6.0beta29 and beta30. There was too much code for too little
+    gain; implementing full ICC color correction may be desirable but is left
+    up to applications.
+
+Version 1.6.0beta32 [November 25, 2012]
+  Fixed an intermittent SEGV in pngstest due to an uninitialized array element.
+  Added the ability for contrib/libtests/makepng.c to make a PNG with just one
+    color. This is useful for debugging pngstest color inaccuracy reports.
+  Fixed error checking in the simplified write API (Olaf van der Spek)
+  Made png_user_version_check() ok to use with libpng version 1.10.x and later.
+
+Version 1.6.0beta33 [December 15, 2012]
+  Fixed typo in png.c (PNG_SET_CHUNK_MALLOC_MAX should be PNG_CHUNK_MALLOC_MAX)
+    that causes the MALLOC_MAX limit not to work (John Bowler)
+  Change png_warning() to png_app_error() in pngwrite.c and comment the
+    fall-through condition.
+  Change png_warning() to png_app_warning() in png_write_tRNS().
+  Rearranged the ARM-NEON optimizations: Isolated the machine specific code
+    to the hardware subdirectory and added comments to pngrutil.c so that
+    implementors of other optimizations know what to do.
+  Fixed cases of unquoted DESTDIR in Makefile.am
+  Rebuilt Makefile.in, etc., with autoconf-2.69 and automake-1.12.5.
+
+Version 1.6.0beta34 [December 19, 2012]
+  Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
+  Disassembled the version number in scripts/options.awk (necessary for
+    building on SunOs).
+
+Version 1.6.0beta35 [December 23, 2012]
+  Made default Zlib compression settings be configurable. This adds #defines to
+    pnglibconf.h to control the defaults.
+  Fixed Windows build issues, enabled ARM compilation. Various warnings issued
+    by earlier versions of GCC fixed for Cygwin and Min/GW (which both use old
+    GCCs.) ARM support is enabled by default in zlib.props (unsupported by
+    Microsoft) and ARM compilation is made possible by deleting the check for
+    x86. The test programs cannot be run because they are not signed.
+
+Version 1.6.0beta36 [January 2, 2013]
+  Discontinued distributing libpng-1.x.x.tar.bz2.
+  Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar.
+  Rebuilt configure with autoconf-2.69 (inadvertently not done in beta33)
+  Fixed 'make distcheck' on SUN OS - libpng.so was not being removed
+
+Version 1.6.0beta37 [January 10, 2013]
+  Fixed conceivable but difficult to repro overflow. Also added two test
+    programs to generate and test a PNG which should have the problem.
+
+Version 1.6.0beta39 [January 19, 2013]
+  Again corrected attempt at overflow detection in png_set_unknown_chunks()
+  (CVE-2013-7353).  Added overflow detection in png_set_sPLT() and
+  png_set_text_2() (CVE-2013-7354).
+
+Version 1.6.0beta40 [January 20, 2013]
+  Use consistent handling of overflows in text, sPLT and unknown png_set_* APIs
+
+Version 1.6.0rc01 [January 26, 2013]
+  No changes.
+
+Version 1.6.0rc02 [February 4, 2013]
+  Added png_get_palette_max() function.
+
+Version 1.6.0rc03 [February 5, 2013]
+  Fixed the png_get_palette_max API.
+
+Version 1.6.0rc04 [February 7, 2013]
+  Turn serial tests back on (recently turned off by autotools upgrade).
+
+Version 1.6.0rc05 [February 8, 2013]
+  Update manual about png_get_palette_max().
+
+Version 1.6.0rc06 [February 9, 2013]
+  Fixed missing dependency in --prefix builds The intermediate
+    internal 'prefix.h' file can only be generated correctly after
+    pnglibconf.h, however the dependency was not in Makefile.am.  The
+    symptoms are unpredictable depending on the order make chooses to
+    build pngprefix.h and pnglibconf.h, often the error goes unnoticed
+    because there is a system pnglibconf.h to use instead.
+
+Version 1.6.0rc07 [February 10, 2013]
+  Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+    block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly.
+
+Version 1.6.0rc08 [February 10, 2013]
+  Fix typo in png.h #ifdef
+
+Version 1.6.0 [February 14, 2013]
+  No changes.
+
+Version 1.6.1beta01 [February 16, 2013]
+  Made symbol prefixing work with the ARM neon optimizations. Also allow
+    pngpriv.h to be included for preprocessor definitions only, so it can
+    be used in non-C/C++ files. Back ported from libpng 1.7.
+  Made sRGB check numbers consistent.
+  Ported libpng 1.5 options.awk/dfn file handling to 1.6, fixed one bug.
+  Removed cc -E workround, corrected png_get_palette_max API Tested on
+    SUN OS cc 5.9, which demonstrates the tokenization problem previously
+    avoided by using /lib/cpp.  Since all .dfn output is now protected in
+    double quotes unless it is to be macro substituted the fix should
+    work everywhere.
+  Enabled parallel tests - back ported from libpng-1.7.
+  scripts/pnglibconf.dfa formatting improvements back ported from libpng17.
+  Fixed a race condition in the creation of the build 'scripts' directory
+    while building with a parallel make.
+  Use approved/supported Android method to check for NEON, use Linux/POSIX
+    1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
+    library calls (ported from libpng15).
+
+Version 1.6.1beta02 [February 19, 2013]
+  Use parentheses more consistently in "#if defined(MACRO)" tests.
+  Folded long lines.
+  Reenabled code to allow zero length PLTE chunks for MNG.
+
+Version 1.6.1beta03 [February 22, 2013]
+  Fixed ALIGNED_MEMORY support.
+  Added a new configure option:
+    --enable-arm-neon=always will stop the run-time checks. New checks
+    within arm/arm_init.c will cause the code not to be compiled unless
+    __ARM_NEON__ is set. This should make it fail safe (if someone asks
+    for it on then the build will fail if it can't be done.)
+  Updated the INSTALL document.
+
+Version 1.6.1beta04 [February 27, 2013]
+  Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES.
+  Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC.
+  Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble
+    with CRLF line endings.
+
+Version 1.6.1beta05 [March 1, 2013]
+  Avoid a possible memory leak in contrib/gregbook/readpng.c
+
+Version 1.6.1beta06 [March 4, 2013]
+  Better documentation of unknown handling API interactions.
+  Corrected Android builds and corrected libpng.vers with symbol
+    prefixing.  It also makes those tests compile and link on Android.
+  Added an API png_set_option() to set optimization options externally,
+    providing an alternative and general solution for the non-portable
+    run-time tests used by the ARM Neon code, using the PNG_ARM_NEON option.
+  The order of settings vs options in pnglibconf.h is reversed to allow
+    settings to depend on options and options can now set (or override) the
+    defaults for settings.
+
+Version 1.6.1beta07 [March 7, 2013]
+  Corrected simplified API default gamma for color-mapped output, added
+    a flag to change default. In 1.6.0 when the simplified API was used
+    to produce color-mapped output from an input image with no gamma
+    information the gamma assumed for the input could be different from
+    that assumed for non-color-mapped output.  In particular 16-bit depth
+    input files were assumed to be sRGB encoded, whereas in the 'direct'
+    case they were assumed to have linear data.  This was an error.  The
+    fix makes the simplified API treat all input files the same way and
+    adds a new flag to the png_image::flags member to allow the
+    application/user to specify that 16-bit files contain sRGB data
+    rather than the default linear.
+  Fixed bugs in the pngpixel and makepng test programs.
+
+Version 1.6.1beta08 [March 7, 2013]
+  Fixed CMakelists.txt to allow building a single variant of the library
+    (Claudio Bley):
+  Introduced a PNG_LIB_TARGETS variable that lists all activated library
+    targets.  It is an error if this variable ends up empty, ie. you have
+    to build at least one library variant.
+  Made the *_COPY targets only depend on library targets actually being build.
+  Use PNG_LIB_TARGETS to unify a code path.
+  Changed the CREATE_SYMLINK macro to expect the full path to a file as the
+    first argument. When symlinking the filename component of that path is
+    determined and used as the link target.
+  Use copy_if_different in the CREATE_SYMLINK macro.
+
+Version 1.6.1beta09 [March 13, 2013]
+  Eliminated two warnings from the Intel C compiler. The warnings are
+    technically valid, although a reasonable treatment of division would
+    show it to be incorrect.
+
+Version 1.6.1rc01 [March 21, 2013]
+  No changes.
+
+Version 1.6.1 [March 28, 2013]
+  No changes.
+
+Version 1.6.2beta01 [April 14, 2013]
+  Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling.
+  Fixed incorrect warning of excess deflate data. End condition - the
+    warning would be produced if the end of the deflate stream wasn't read
+    in the last row.  The warning is harmless.
+  Corrected the test on user transform changes on read. It was in the
+    png_set of the transform function, but that doesn't matter unless the
+    transform function changes the rowbuf size, and that is only valid if
+    transform_info is called.
+  Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c
+    (Flavio Medeiros).
+  Corrected length written to uncompressed iTXt chunks (Samuli Suominen).
+    Bug was introduced in libpng-1.6.0.
+
+Version 1.6.2rc01 [April 18, 2013]
+  Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length
+    written by libpng-1.6.0 and 1.6.1.
+  Disallow storing sRGB information when the sRGB is not supported.
+
+Version 1.6.2rc02 [April 18, 2013]
+  Merge pngtest.c with libpng-1.7.0
+
+Version 1.6.2rc03 [April 22, 2013]
+  Trivial spelling cleanup.
+
+Version 1.6.2rc04 and 1.6.2rc05 [omitted]
+
+Version 1.6.2rc06 [April 24, 2013]
+  Reverted to version 1.6.2rc03.  Recent changes to arm/neon support
+    have been ported to libpng-1.7.0beta09 and will reappear in version
+    1.6.3beta01.
+
+Version 1.6.2 [April 25, 2013]
+  No changes.
+
+Version 1.6.3beta01 [April 25, 2013]
+  Revised stack marking in arm/filter_neon.S and configure.ac.
+  Ensure that NEON filter stuff is completely disabled when switched 'off'.
+    Previously the ARM NEON specific files were still built if the option
+    was switched 'off' as opposed to being explicitly disabled.
+
+Version 1.6.3beta02 [April 26, 2013]
+  Test for 'arm*' not just 'arm' in the host_cpu configure variable.
+  Rebuilt the configure scripts.
+
+Version 1.6.3beta03 [April 30, 2013]
+  Expanded manual paragraph about writing private chunks, particularly
+    the need to call png_set_keep_unknown_chunks() when writing them.
+  Avoid dereferencing NULL pointer possibly returned from
+    png_create_write_struct() (Andrew Church).
+
+Version 1.6.3beta05 [May 9, 2013]
+  Calculate our own zlib windowBits when decoding rather than trusting the
+    CMF bytes in the PNG datastream.
+  Added an option to force maximum window size for inflating, which was
+    the behavior of libpng15 and earlier, via a new PNG_MAXIMUM_INFLATE_WINDOW
+    option for png_set_options().
+  Added png-fix-itxt and png-fix-too-far-back to the built programs and
+    removed warnings from the source code and timepng that are revealed as
+    a result.
+  Detect wrong libpng versions linked to png-fix-too-far-back, which currently
+    only works with libpng versions that can be made to reliably fail when
+    the deflate data contains an out-of-window reference.  This means only
+    1.6 and later.
+  Fixed gnu issues: g++ needs a static_cast, gcc 4.4.7 has a broken warning
+    message which it is easier to work round than ignore.
+  Updated contrib/pngminus/pnm2png.c (Paul Stewart):
+    Check for EOF
+    Ignore "#" delimited comments in input file to pnm2png.c.
+    Fixed whitespace handling
+    Added a call to png_set_packing()
+    Initialize dimension values so if sscanf fails at least we have known
+      invalid values.
+  Attempt to detect configuration issues with png-fix-too-far-back, which
+    requires both the correct libpng and the correct zlib to function
+    correctly.
+  Check ZLIB_VERNUM for mismatches, enclose #error in quotes
+  Added information in the documentation about problems with and fixes for
+    the bad CRC and bad iTXt chunk situations.
+
+Version 1.6.3beta06 [May 12, 2013]
+  Allow contrib/pngminus/pnm2png.c to compile without WRITE_INVERT and
+    WRITE_PACK supported (writes error message that it can't read P1 or
+    P4 PBM files).
+  Improved png-fix-too-far-back usage message, added --suffix option.
+  Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
+    right zlib header files.
+  Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
+
+Version 1.6.3beta07 [June 8, 2013]
+  Removed a redundant test in png_set_IHDR().
+  Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt)
+  Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
+  Enclose the prototypes for the simplified write API in
+    #ifdef PNG_STDIO_SUPPORTED/#endif
+  Make ARM NEON support work at compile time (not just configure time).
+    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
+    using a compiler that compiles for multiple architectures at one time.
+  Removed PNG_FILTER_OPTIMIZATIONS and PNG_ARM_NEON_SUPPORTED from
+    pnglibconf.h, allowing more of the decisions to be made internally
+    (pngpriv.h) during the compile.  Without this, symbol prefixing is broken
+    under certain circumstances on ARM platforms.  Now only the API parts of
+    the optimizations ('check' vs 'api') are exposed in the public header files
+    except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the
+    decision about whether or not to use the optimizations.
+  Protect symbol prefixing against CC/CPPFLAGS/CFLAGS usage.
+    Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test
+    on __ARM_NEON__ from configure time to compile time.  This breaks symbol
+    prefixing because the definition of the special png_init_filter_functions
+    call was hidden at configure time if the relevant compiler arguments are
+    passed in CFLAGS as opposed to CC.  This change attempts to avoid all
+    the confusion that would result by declaring the init function even when
+    it is not used, so that it will always get prefixed.
+
+Version 1.6.3beta08 [June 18, 2013]
+  Revised libpng.3 so that "doclifter" can process it.
+
+Version 1.6.3beta09 [June 27, 2013]
+  Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
+    as parameters for png_set_gamma().  These have been available since
+    libpng-1.5.4.
+  Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
+    to check all compressed chunks known to libpng.
+
+Version 1.6.3beta10 [July 5, 2013]
+  Updated documentation to show default behavior of benign errors correctly.
+  Only compile ARM code when PNG_READ_SUPPORTED is defined.
+  Fixed undefined behavior in contrib/tools/pngfix.c and added new strip
+    option. pngfix relied on undefined behavior and even a simple change from
+    gcc to g++ caused it to fail.  The new strip option 'unsafe' has been
+    implemented and is the default if --max is given.  Option names have
+    been clarified, with --strip=transform now stripping the bKGD chunk,
+    which was stripped previously with --strip=unused.
+  Added all documented chunk types to pngpriv.h
+  Unified pngfix.c source with libpng17.
+
+Version 1.6.3rc01 [July 11, 2013]
+  No changes.
+
+Version 1.6.3 [July 18, 2013]
+  Revised manual about changes in iTXt chunk handling made in libpng-1.6.0.
+  Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings
+    may be erroneously issued by code-checking applications.
+
+Version 1.6.4beta01 [August 21, 2013]
+  Added information about png_set_options() to the manual.
+  Delay calling png_init_filter_functions() until a row with nonzero filter
+    is found.
+
+Version 1.6.4beta02 [August 30, 2013]
+  Fixed inconsistent conditional compilation of png_chunk_unknown_handling()
+    prototype, definition, and usage.  Made it depend on
+    PNG_HANDLE_AS_UNKNOWN_SUPPORTED everywhere.
+
+Version 1.6.4rc01 [September 5, 2013]
+  No changes.
+
+Version 1.6.4 [September 12, 2013]
+  No changes.
+
+Version 1.6.5 [September 14, 2013]
+  Removed two stray lines of code from arm/arm_init.c.
+
+Version 1.6.6 [September 16, 2013]
+  Removed two stray lines of code from arm/arm_init.c, again.
+
+Version 1.6.7beta01 [September 30, 2013]
+  Revised unknown chunk code to correct several bugs in the NO_SAVE_/NO_WRITE
+    combination
+  Allow HANDLE_AS_UNKNOWN to work when other options are configured off. Also
+    fixed the pngminim makefiles to work when $(MAKEFLAGS) contains stuff
+    which terminates the make options (as by default in recent versions of
+    Gentoo).
+  Avoid up-cast warnings in pngvalid.c. On ARM the alignment requirements of
+    png_modifier are greater than that of png_store and as a consequence
+    compilation of pngvalid.c results in a warning about increased alignment
+    requirements because of the bare cast to (png_modifier*). The code is safe,
+    because the pointer is known to point to a stack allocated png_modifier,
+    but this change avoids the warning.
+  Fixed default behavior of ARM_NEON_API. If the ARM NEON API option was
+    compiled without the CHECK option it defaulted to on, not off.
+  Check user callback behavior in pngunknown.c. Previous versions compiled
+    if SAVE_UNKNOWN was not available but did nothing since the callback
+    was never implemented.
+  Merged pngunknown.c with 1.7 version and back ported 1.7 improvements/fixes
+
+Version 1.6.7beta02 [October 12, 2013]
+  Made changes for compatibility with automake 1.14:
+    1) Added the 'compile' program to the list of programs that must be cleaned
+       in autogen.sh
+    2) Added 'subdir-objects' which causes .c files in sub-directories to be
+       compiled such that the corresponding .o files are also in the
+       sub-directory.  This is because automake 1.14 warns that the
+       current behavior of compiling to the top level directory may be removed
+       in the future.
+    3) Updated dependencies on pnglibconf.h to match the new .o locations and
+       added all the files in contrib/libtests and contrib/tools that depend
+       on pnglibconf.h
+    4) Added 'BUILD_SOURCES = pnglibconf.h'; this is the automake recommended
+       way of handling the dependencies of sources that are machine generated;
+       unfortunately it only works if the user does 'make all' or 'make check',
+       so the dependencies (3) are still required.
+  Cleaned up (char*) casts of zlib messages. The latest version of the Intel C
+    compiler complains about casting a string literal as (char*), so copied the
+    treatment of z_const from the library code into pngfix.c
+  Simplified error message code in pngunknown. The simplification has the
+    useful side effect of avoiding a bogus warning generated by the latest
+    version of the Intel C compiler (it objects to
+    condition ? string-literal : string-literal).
+  Make autogen.sh work with automake 1.13 as well as 1.14. Do this by always
+    removing the 1.14 'compile' script but never checking for it.
+
+Version 1.6.7beta03 [October 19, 2013]
+  Added ARMv8 support (James Yu <james.yu at linaro.org>).  Added file
+    arm/filter_neon_intrinsics.c; enable with -mfpu=neon.
+  Revised pngvalid to generate size images with as many filters as it can
+    manage, limited by the number of rows.
+  Cleaned up ARM NEON compilation handling. The tests are now in pngpriv.h
+    and detect the broken GCC compilers.
+
+Version 1.6.7beta04 [October 26, 2013]
+  Allow clang derived from older GCC versions to use ARM intrinsics. This
+    causes all clang builds that use -mfpu=neon to use the intrinsics code,
+    not the assembler code.  This has only been tested on iOS 7. It may be
+    necessary to exclude some earlier clang versions but this seems unlikely.
+  Changed NEON implementation selection mechanism. This allows assembler
+    or intrinsics to be turned on at compile time during the build by defining
+    PNG_ARM_NEON_IMPLEMENTATION to the correct value (2 or 1).  This macro
+    is undefined by default and the build type is selected in pngpriv.h.
+
+Version 1.6.7rc01 [November 2, 2013]
+  No changes.
+
+Version 1.6.7rc02 [November 7, 2013]
+  Fixed #include in filter_neon_intrinsics.c and ctype macros. The ctype char
+    checking macros take an unsigned char argument, not a signed char.
+
+Version 1.6.7 [November 14, 2013]
+  No changes.
+
+Version 1.6.8beta01 [November 24, 2013]
+  Moved prototype for png_handle_unknown() in pngpriv.h outside of
+    the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
+  Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
+  Conditionally compile some unused functions reported by -Wall in
+    pngminim.
+  Fixed 'minimal' builds. Various obviously useful minimal configurations
+    don't build because of missing contrib/libtests test programs and
+    overly complex dependencies in scripts/pnglibconf.dfa. This change
+    adds contrib/conftest/*.dfa files that can be used in automatic build
+    scripts to ensure that these configurations continue to build.
+  Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder.
+  Fixed pngvalid 'fail' function declaration on the Intel C Compiler.
+    This reverts to the previous 'static' implementation and works round
+    the 'unused static function' warning by using PNG_UNUSED().
+
+Version 1.6.8beta02 [November 30, 2013]
+  Removed or marked PNG_UNUSED some harmless "dead assignments" reported
+    by clang scan-build.
+  Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
+    to '"%s" m' to improve portability among compilers.
+  Changed png_free_default() to free() in pngtest.c
+
+Version 1.6.8rc01 [December 12, 2013]
+  Tidied up pngfix inits and fixed pngtest no-write builds.
+
+Version 1.6.8rc02 [December 14, 2013]
+  Handle zero-length PLTE chunk or NULL palette with png_error()
+    instead of png_chunk_report(), which by default issues a warning
+    rather than an error, leading to later reading from a NULL pointer
+    (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
+    and VU#650142.  Libpng-1.6.1 through 1.6.7 are vulnerable.
+    Libpng-1.6.0 and earlier do not have this bug.
+
+Version 1.6.8 [December 19, 2013]
+  No changes.
+
+Version 1.6.9beta01 [December 26, 2013]
+  Bookkeeping: Moved functions around (no changes). Moved transform
+    function definitions before the place where they are called so that
+    they can be made static. Move the intrapixel functions and the
+    grayscale palette builder out of the png?tran.c files. The latter
+    isn't a transform function and is no longer used internally, and the
+    former MNG specific functions are better placed in pngread/pngwrite.c
+  Made transform implementation functions static. This makes the internal
+    functions called by png_do_{read|write}_transformations static. On an
+    x86-64 DLL build (Gentoo Linux) this reduces the size of the text
+    segment of the DLL by 1208 bytes, about 0.6%. It also simplifies
+    maintenance by removing the declarations from pngpriv.h and allowing
+    easier changes to the internal interfaces.
+  Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69
+    in the tar distributions.
+
+Version 1.6.9beta02 [January 1, 2014]
+  Added checks for libpng 1.5 to pngvalid.c.  This supports the use of
+    this version of pngvalid in libpng 1.5
+  Merged with pngvalid.c from libpng-1.7 changes to create a single
+    pngvalid.c
+  Removed #error macro from contrib/tools/pngfix.c (Thomas Klausner).
+  Merged pngrio.c, pngtrans.c, pngwio.c, and pngerror.c with libpng-1.7.0
+  Merged libpng-1.7.0 changes to make no-interlace configurations work
+    with test programs.
+  Revised pngvalid.c to support libpng 1.5, which does not support the
+    PNG_MAXIMUM_INFLATE_WINDOW option, so #define it out when appropriate in
+    pngvalid.c
+  Allow unversioned links created on install to be disabled in configure.
+    In configure builds 'make install' changes/adds links like png.h
+    and libpng.a to point to the newly installed, versioned, files (e.g.
+    libpng17/png.h and libpng17.a). Three new configure options and some
+    rearrangement of Makefile.am allow creation of these links to be disabled.
+
+Version 1.6.9beta03 [January 10, 2014]
+  Removed potentially misleading warning from png_check_IHDR().
+
+Version 1.6.9beta04 [January 20, 2014]
+  Updated scripts/makefile.* to use CPPFLAGS (Cosmin).
+  Added clang attribute support (Cosmin).
+
+Version 1.6.9rc01 [January 28, 2014]
+  No changes.
+
+Version 1.6.9rc02 [January 30, 2014]
+  Quiet an uninitialized memory warning from VC2013 in png_get_png().
+
+Version 1.6.9 [February 6, 2014]
+
+Version 1.6.10beta01 [February 9, 2014]
+  Backported changes from libpng-1.7.0beta30 and beta31:
+  Fixed a large number of instances where PNGCBAPI was omitted from
+    function definitions.
+  Added pngimage test program for png_read_png() and png_write_png()
+    with two new test scripts.
+  Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling
+    png_set_packing() in png_read_png().
+  Fixed combination of ~alpha with shift. On read invert alpha, processing
+    occurred after shift processing, which causes the final values to be
+    outside the range that should be produced by the shift. Reversing the
+    order on read makes the two transforms work together correctly and mirrors
+    the order used on write.
+  Do not read invalid sBIT chunks. Previously libpng only checked sBIT
+    values on write, so a malicious PNG writer could therefore cause
+    the read code to return an invalid sBIT chunk, which might lead to
+    application errors or crashes.  Such chunks are now skipped (with
+    chunk_benign_error).
+  Make png_read_png() and png_write_png() prototypes in png.h depend
+    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
+  Support builds with unsupported PNG_TRANSFORM_* values.  All of the
+    PNG_TRANSFORM_* values are always defined in png.h and, because they
+    are used for both read and write in some cases, it is not reliable
+    to #if out ones that are totally unsupported. This change adds error
+    detection in png_read_image() and png_write_image() to do a
+    png_app_error() if the app requests something that cannot be done
+    and it adds corresponding code to pngimage.c to handle such options
+    by not attempting to test them.
+
+Version 1.6.10beta02 [February 23, 2014]
+  Moved redefines of png_error(), png_warning(), png_chunk_error(),
+    and png_chunk_warning() from pngpriv.h to png.h to make them visible
+    to libpng-calling applications.
+  Moved OS dependent code from arm/arm_init.c, to allow the included
+    implementation of the ARM NEON discovery function to be set at
+    build-time and provide sample implementations from the current code in the
+    contrib/arm-neon subdirectory. The __linux__ code has also been changed to
+    compile and link on Android by using /proc/cpuinfo, and the old linux code
+    is in contrib/arm-neon/linux-auxv.c.  The new code avoids POSIX and Linux
+    dependencies apart from opening /proc/cpuinfo and is C90 compliant.
+  Check for info_ptr == NULL early in png_read_end() so we don't need to
+    run all the png_handle_*() and depend on them to return if info_ptr == NULL.
+    This improves the performance of png_read_end(png_ptr, NULL) and makes
+    it more robust against future programming errors.
+  Check for __has_extension before using it in pngconf.h, to
+    support older Clang versions (Jeremy Sequoia).
+  Treat CRC error handling with png_set_crc_action(), instead of with
+    png_set_benign_errors(), which has been the case since libpng-1.6.0beta18.
+  Use a user warning handler in contrib/gregbook/readpng2.c instead of default,
+    so warnings will be put on stderr even if libpng has CONSOLE_IO disabled.
+  Added png_ptr->process_mode = PNG_READ_IDAT_MODE in png_push_read_chunk
+    after recognizing the IDAT chunk, which avoids an infinite loop while
+    reading a datastream whose first IDAT chunk is of zero-length.
+    This fixes CERT VU#684412 and CVE-2014-0333.
+  Don't recognize known sRGB profiles as sRGB if they have been hacked,
+    but don't reject them and don't issue a copyright violation warning.
+
+Version 1.6.10beta03 [February 25, 2014]
+  Moved some documentation from png.h to libpng.3 and libpng-manual.txt
+  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
+
+Version 1.6.10rc01 [February 27, 2014]
+  Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS
+    and PNG_USR_CONFIG -> PNG_USER_CONFIG).
+
+Version 1.6.10rc02 [February 28, 2014]
+  Removed unreachable return statement after png_chunk_error()
+    in pngrutil.c
+
+Version 1.6.10rc03 [March 4, 2014]
+  Un-deprecated png_data_freer().
+
+Version 1.6.10 [March 6, 2014]
+  No changes.
+
+Version 1.6.11beta01 [March 17, 2014]
+  Use "if (value != 0)" instead of "if (value)" consistently.
+  Changed ZlibSrcDir from 1.2.5 to 1.2.8 in projects/vstudio.
+  Moved configuration information from the manual to the INSTALL file.
+
+Version 1.6.11beta02 [April 6, 2014]
+  Removed #if/#else/#endif from inside two pow() calls in pngvalid.c because
+    they were handled improperly by Portland Group's PGI-14.1 - PGI-14.3
+    when using its "__builtin_pow()" function.
+  Silence 'unused parameter' build warnings (Cosmin Truta).
+  $(CP) is now used alongside $(RM_F).  Also, use 'copy' instead of 'cp'
+    where applicable, and applied other minor makefile changes (Cosmin).
+  Don't warn about invalid dimensions exceeding user limits (Cosmin).
+  Allow an easy replacement of the default pre-built configuration
+    header with a custom header, via the make PNGLIBCONF_H_PREBUILT
+    macro (Cosmin).
+
+Version 1.6.11beta03 [April 6, 2014]
+  Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes
+    with "blocky" expansion of sub-8-bit interlaced PNG files (Eric Huss).
+  Optionally use  __builtin_bswap16() in png_do_swap().
+
+Version 1.6.11beta04 [April 19, 2014]
+  Made progressive reading of interlaced images consistent with the
+    behavior of the sequential reader and consistent with the manual, by
+    moving some code out of the PNG_READ_INTERLACING_SUPPORTED blocks. The
+    row_callback now receives the proper pass number and unexpanded rows, when
+    png_combine_row() isn't built or used, and png_set_interlace_handling()
+    is not called.
+  Allow PNG_sRGB_PROFILE_CHECKING = (-1) to mean no sRGB profile checking.
+
+Version 1.6.11beta05 [April 26, 2014]
+  Do not reject ICC V2 profiles that lack padding (Kai-Uwe Behrmann).
+  Relocated closing bracket of the sRGB profile test loop to avoid getting
+    "Not recognizing known sRGB profile that has been edited" warning for
+    ICC V2 profiles that lack the MD5 signature in the profile header.
+
+Version 1.6.11beta06 [May 19, 2014]
+  Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option().
+
+Version 1.6.11rc01 [May 27, 2014]
+  No changes.
+
+Version 1.6.11rc02 [June 3, 2014]
+  Test ZLIB_VERNUM instead of PNG_ZLIB_VERNUM in contrib/tools/pngfix.c
+
+Version 1.6.11 [June 5, 2014]
+  No changes.
+
+Version 1.6.12rc01 [June 6, 2014]
+  Relocated new code from 1.6.11beta06 in png.c to a point after the
+    declarations (Max Stepin).
+
+Version 1.6.12rc02 [June 7, 2014]
+  Changed file permissions of contrib/tools/intgamma.sh,
+    test-driver, and compile from 0644 to 0755 (Cosmin).
+
+Version 1.6.12rc03 [June 8, 2014]
+  Ensure "__has_attribute()" macro exists before trying to use it with
+    old clang compilers (MacPorts Ticket #43939).
+
+Version 1.6.12 [June 12, 2014]
+  No changes.
+
+Version 1.6.13beta01 [July 4, 2014]
+  Quieted -Wsign-compare and -Wclobber compiler warnings in
+    contrib/pngminus/*.c
+  Added "(void) png_ptr;" where needed in contrib/gregbook to quiet
+    compiler complaints about unused pointers.
+  Split a long output string in contrib/gregbook/rpng2-x.c.
+  Added "PNG_SET_OPTION" requirement for sRGB chunk support to pnglibconf.dfa,
+    Needed for write-only support (John Bowler).
+  Changed "if defined(__ARM_NEON__)" to
+    "if (defined(__ARM_NEON__) || defined(__ARM_NEON))" (James Wu).
+  Fixed clang no-warning builds: png_digit was defined but never used.
+
+Version 1.6.13beta02 [July 21, 2014]
+  Fixed an incorrect separator ("/" should be "\") in scripts/makefile.vcwin32
+    (bug report from Wolfgang S. Kechel).  Bug was introduced in libpng-1.6.11.
+    Also fixed makefile.bc32, makefile.bor, makefile.msc, makefile.intel, and
+    makefile.tc3 similarly.
+
+Version 1.6.13beta03 [August 3, 2014]
+  Removed scripts/makefile.elf. It has not worked since libpng-1.5.0beta14
+    due to elimination of the PNG_FUNCTION_EXPORT and PNG_DATA_EXPORT
+    definitions from pngconf.h.
+  Ensure that CMakeLists.txt makes the target "lib" directory before making
+    symbolic link into it (SourceForge bug report #226 by Rolf Timmermans).
+
+Version 1.6.13beta04 [August 8, 2014]
+  Added opinion that the ECCN (Export Control Classification Number) for
+    libpng is EAR99 to the README file.
+  Eliminated use of "$<" in makefile explicit rules, when copying
+    $PNGLIBCONF_H_PREBUILT.  This does not work on some versions of make;
+    bug introduced in libpng version 1.6.11.
+
+Version 1.6.13rc01 [August 14, 2014]
+  Made "ccopts" agree with "CFLAGS" in scripts/makefile.hp* and makefile.*sunu
+
+Version 1.6.13 [August 21, 2014]
+  No changes.
+
+Version 1.6.14beta01 [September 14, 2014]
+  Guard usage of png_ptr->options with #ifdef PNG_SET_OPTION_SUPPORTED.
+  Do not build contrib/tools/pngfix.c when PNG_SETJMP_NOT_SUPPORTED,
+    to allow "make" to complete without setjmp support (bug report by
+    Claudio Fontana)
+  Add "#include <setjmp.h>" to contrib/tools/pngfix.c (John Bowler)
+
+Version 1.6.14beta02 [September 18, 2014]
+  Use nanosleep() instead of usleep() in contrib/gregbook/rpng2-x.c
+    because usleep() is deprecated.
+  Define usleep() in contrib/gregbook/rpng2-x.c if not already defined
+    in unistd.h and nanosleep() is not available; fixes error introduced
+    in libpng-1.6.13.
+  Disable floating point exception handling in pngvalid.c when
+    PNG_FLOATING_ARITHMETIC is not supported (bug report by "zootus
+    at users.sourceforge.net").
+
+Version 1.6.14beta03 [September 19, 2014]
+  Define FE_DIVBYZERO, FE_INVALID, and FE_OVERFLOW in pngvalid.c if not
+    already defined.  Revert floating point exception handling in pngvalid.c
+    to version 1.6.14beta01 behavior.
+
+Version 1.6.14beta04 [September 27, 2014]
+  Fixed incorrect handling of the iTXt compression flag in pngrutil.c
+    (bug report by Shunsaku Hirata).  Bug was introduced in libpng-1.6.0.
+
+Version 1.6.14beta05 [October 1, 2014]
+  Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
+
+Version 1.6.14beta06 [October 5, 2014]
+  Removed unused "text_len" parameter from private function png_write_zTXt().
+  Conditionally compile some code in png_deflate_claim(), when
+    PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.
+  Replaced repeated code in pngpread.c with PNG_PUSH_SAVE_BUFFER_IF_FULL.
+  Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT"
+    to pnglibconf.dfa.
+  Removed "option READ_COMPRESSED_TEXT enables READ_TEXT" from pnglibconf.dfa,
+    to make it possible to configure a libpng that supports iCCP but not TEXT.
+
+Version 1.6.14beta07 [October 7, 2014]
+  Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
+  Only mark text chunks as written after successfully writing them.
+
+Version 1.6.14rc01 [October 15, 2014]
+  Fixed some typos in comments.
+
+Version 1.6.14rc02 [October 17, 2014]
+  Changed png_convert_to_rfc_1123() to png_convert_to_rfc_1123_buffer()
+    in the manual, to reflect the change made in libpng-1.6.0.
+  Updated README file to explain that direct access to the png_struct
+    and info_struct members has not been permitted since libpng-1.5.0.
+
+Version 1.6.14 [October 23, 2014]
+  No changes.
+
+Version 1.6.15beta01 [October 29, 2014]
+  Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+  Simplified png_free_data().
+  Added missing "ptr = NULL" after some instances of png_free().
+
+Version 1.6.15beta02 [November 1, 2014]
+  Changed remaining "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+
+Version 1.6.15beta03 [November 3, 2014]
+  Added PNG_USE_ARM_NEON configuration flag (Marcin Juszkiewicz).
+
+Version 1.6.15beta04 [November 4, 2014]
+  Removed new PNG_USE_ARM_NEON configuration flag and made a one-line
+    revision to configure.ac to support ARM on aarch64 instead (John Bowler).
+
+Version 1.6.15beta05 [November 5, 2014]
+  Use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING in
+    example.c, pngtest.c, and applications in the contrib directory.
+  Fixed an out-of-range read in png_user_version_check() (Bug report from
+    Qixue Xiao, CVE-2015-8540).
+  Simplified and future-proofed png_user_version_check().
+  Fixed GCC unsigned int->float warnings. Various versions of GCC
+    seem to generate warnings when an unsigned value is implicitly
+    converted to double. This is probably a GCC bug but this change
+    avoids the issue by explicitly converting to (int) where safe.
+  Free all allocated memory in pngimage. The file buffer cache was left
+    allocated at the end of the program, harmless but it causes memory
+    leak reports from clang.
+  Fixed array size calculations to avoid warnings. At various points
+    in the code the number of elements in an array is calculated using
+    sizeof.  This generates a compile time constant of type (size_t) which
+    is then typically assigned to an (unsigned int) or (int). Some versions
+    of GCC on 64-bit systems warn about the apparent narrowing, even though
+    the same compiler does apparently generate the correct, in-range,
+    numeric constant.  This adds appropriate, safe, casts to make the
+    warnings go away.
+
+Version 1.6.15beta06 [November 6, 2014]
+  Reverted use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING
+    in the manual, example.c, pngtest.c, and applications in the contrib
+    directory.  It was incorrect advice.
+
+Version 1.6.15beta07 [November 7, 2014]
+  Removed #ifdef PNG_16BIT_SUPPORTED/#endif around png_product2(); it is
+    needed by png_reciprocal2().
+  Added #ifdef PNG_16BIT_SUPPORTED/#endif around png_log16bit() and
+    png_do_swap().
+  Changed all "#endif /* PNG_FEATURE_SUPPORTED */" to "#endif /* FEATURE */"
+
+Version 1.6.15beta08 [November 8, 2014]
+  More housecleaning in *.h
+
+Version 1.6.15rc01 [November 13, 2014]
+
+Version 1.6.15rc02 [November 14, 2014]
+  The macros passed in the command line to Borland make were ignored if
+    similarly-named macros were already defined in makefiles. This behavior
+    is different from POSIX make and other make programs.  Surround the
+    macro definitions with ifndef guards (Cosmin).
+
+Version 1.6.15rc03 [November 16, 2014]
+  Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in scripts/makefile.vcwin32.
+  Removed the obsolete $ARCH variable from scripts/makefile.darwin.
+
+Version 1.6.15 [November 20, 2014]
+  No changes.
+
+Version 1.6.16beta01 [December 14, 2014]
+  Added ".align 2" to arm/filter_neon.S to support old GAS assemblers that
+    don't do alignment correctly.
+  Revised Makefile.am and scripts/symbols.dfn to work with MinGW/MSYS
+    (Bob Friesenhahn).
+
+Version 1.6.16beta02 [December 15, 2014]
+  Revised Makefile.am and scripts/*.dfn again to work with MinGW/MSYS;
+    renamed scripts/*.dfn to scripts/*.c (John Bowler).
+
+Version 1.6.16beta03 [December 21, 2014]
+  Quiet a "comparison always true" warning in pngstest.c (John Bowler).
+
+Version 1.6.16rc01 [December 21, 2014]
+  Restored a test on width that was removed from png.c at libpng-1.6.9
+    (Bug report by Alex Eubanks, CVE-2015-0973).
+
+Version 1.6.16rc02 [December 21, 2014]
+  Undid the update to pngrutil.c in 1.6.16rc01.
+
+Version 1.6.16rc03 [December 21, 2014]
+  Fixed an overflow in png_combine_row() with very wide interlaced images
+    (Bug report and fix by John Bowler, CVE-2014-9495).
+
+Version 1.6.16 [December 22, 2014]
+  No changes.
+
+Version 1.6.17beta01 [January 29, 2015]
+  Removed duplicate PNG_SAFE_LIMITS_SUPPORTED handling from pngconf.h
+  Corrected the width limit calculation in png_check_IHDR().
+  Removed user limits from pngfix. Also pass NULL pointers to
+    png_read_row to skip the unnecessary row de-interlace stuff.
+  Added testing of png_set_packing() to pngvalid.c
+  Regenerated configure scripts in the *.tar distributions with libtool-2.4.4
+  Implement previously untested cases of libpng transforms in pngvalid.c
+  Fixed byte order in png_do_read_filler() with 16-bit input. Previously
+    the high and low bytes of the filler, from png_set_filler() or from
+    png_set_add_alpha(), were read in the wrong order.
+  Made the check for out-of-range values in png_set_tRNS() detect
+    values that are exactly 2^bit_depth, and work on 16-bit platforms.
+  Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
+  Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
+    pngset.c to avoid warnings about dead code.
+  Added "& 0xff" to many instances of expressions that are typecast
+    to (png_byte), to avoid Coverity warnings.
+
+Version 1.6.17beta02 [February 7, 2015]
+  Work around one more Coverity-scan dead-code warning.
+  Do not build png_product2() when it is unused.
+
+Version 1.6.17beta03 [February 17, 2015]
+  Display user limits in the output from pngtest.
+  Eliminated the PNG_SAFE_LIMITS macro and restored the 1-million-column
+    and 1-million-row default limits in pnglibconf.dfa, that can be reset
+    by the user at build time or run time.  This provides a more robust
+    defense against DOS and as-yet undiscovered overflows.
+
+Version 1.6.17beta04 [February 21, 2015]
+  Added PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED macro, on by default.
+  Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
+  Rebuilt configure scripts with automake-1.15 and libtool-2.4.6
+
+Version 1.6.17beta05 [February 25, 2015]
+  Restored compiling of png_reciprocal2 with PNG_NO_16BIT.
+
+Version 1.6.17beta06 [February 27, 2015]
+  Moved png_set_filter() prototype into a PNG_WRITE_SUPPORTED block
+    of png.h.
+  Avoid runtime checks when converting integer to png_byte with
+    Visual Studio (Sergey Kosarevsky)
+
+Version 1.6.17rc01 [March 4, 2015]
+  No changes.
+
+Version 1.6.17rc02 [March 9, 2015]
+  Removed some comments that the configure script did not handle
+    properly from scripts/pnglibconf.dfa and pnglibconf.h.prebuilt.
+  Free the unknown_chunks structure even when it contains no data.
+
+Version 1.6.17rc03 [March 12, 2015]
+  Updated CMakeLists.txt to add OSX framework, change YES/NO to ON/OFF
+    for consistency, and remove some useless tests (Alexey Petruchik).
+
+Version 1.6.17rc04 [March 16, 2015]
+  Remove pnglibconf.h, pnglibconf.c, and pnglibconf.out instead of
+    pnglibconf.* in "make clean" (Cosmin).
+  Fix bug in calculation of maxbits, in png_write_sBIT, introduced
+    in libpng-1.6.17beta01 (John Bowler).
+
+Version 1.6.17rc05 [March 21, 2015]
+  Define PNG_FILTER_* and PNG_FILTER_VALUE_* in png.h even when WRITE
+    is not supported (John Bowler).  This fixes an error introduced in
+    libpng-1.6.17beta06.
+  Reverted "& 0xff" additions of version 1.6.17beta01. Libpng passes
+    the Coverity scan without them.
+
+Version 1.6.17rc06 [March 23, 2015]
+  Remove pnglibconf.dfn and pnglibconf.pre with "make clean".
+  Reformatted some "&0xff" instances to "& 0xff".
+  Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
+    value was wrong.  It's not clear if this affected the final stored
+    value; in the obvious code path the upper and lower 8-bits of the
+    alpha value were identical and the alpha was truncated to 8-bits
+    rather than dividing by 257 (John Bowler).
+
+Version 1.6.17 [March 26, 2015]
+  No changes.
+
+Version 1.6.18beta01 [April 1, 2015]
+  Removed PNG_SET_CHUNK_[CACHE|MALLOC]_LIMIT_SUPPORTED macros.  They
+    have been combined with PNG_SET_USER_LIMITS_SUPPORTED (resolves
+    bug report by Andrew Church).
+  Fixed rgb_to_gray checks and added tRNS checks to pngvalid.c.  This
+    fixes some arithmetic errors that caused some tests to fail on
+    some 32-bit platforms (Bug reports by Peter Breitenlohner [i686]
+    and Petr Gajdos [i586]).
+
+Version 1.6.18beta02 [April 26, 2015]
+  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
+    (Bug report by Viktor Szakats).
+
+Version 1.6.18beta03 [May 6, 2015]
+  Replaced "unexpected" with an integer (0xabadca11) in pngset.c
+    where a long was expected, to avoid a compiler warning when PNG_DEBUG > 1.
+  Added contrib/examples/simpleover.c, to demonstrate how to handle
+    alpha compositing of multiple images, using the "simplified API"
+    and an example PNG generation tool, contrib/examples/genpng.c
+    (John Bowler).
+
+Version 1.6.18beta04 [May 20, 2015]
+  PNG_RELEASE_BUILD replaces tests where the code depended on the build base
+    type and can be defined on the command line, allowing testing in beta
+    builds (John Bowler).
+  Avoid Coverity issue 80858 (REVERSE NULL) in pngtest.c PNG_DEBUG builds.
+  Avoid a harmless potential integer overflow in png_XYZ_from_xy() (Bug
+    report from Christopher Ferris).
+
+Version 1.6.18beta05 [May 31, 2015]
+  Backport filter selection code from libpng-1.7.0beta51, to combine
+    sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
+  Changed png_voidcast(), etc., to voidcast(), etc., in contrib/tools/pngfix.c
+    to avoid confusion with the libpng private macros.
+  Fixed old cut&paste bug in the weighted filter selection code in
+    pngwutil.c, introduced in libpng-0.95, March 1997.
+
+Version 1.6.18beta06 [June 1, 2015]
+  Removed WRITE_WEIGHTED_FILTERED code, to save a few kbytes of the
+    compiled library size. It never worked properly and as far as we can
+    tell, no one uses it. The png_set_filter_heuristics() and
+    png_set_filter_heuristics_fixed() APIs are retained but deprecated
+    and do nothing.
+
+Version 1.6.18beta07 [June 6, 2015]
+  Removed non-working progressive reader 'skip' function. This
+    function has apparently never been used. It was implemented
+    to support back-door modification of png_struct in libpng-1.4.x
+    but (because it does nothing and cannot do anything) was apparently
+    never tested (John Bowler).
+  Fixed cexcept.h in which GCC 5 now reports that one of the auto
+    variables in the Try macro needs to be volatile to prevent value
+    being lost over the setjmp (John Bowler).
+  Fixed NO_WRITE_FILTER and -Wconversion build breaks (John Bowler).
+  Fix g++ build breaks (John Bowler).
+  Quieted some Coverity issues in pngfix.c, png-fix-itxt.c, pngvalid.c,
+    pngstest.c, and pngimage.c. Most seem harmless, but png-fix-itxt
+    would only work with iTXt chunks with length 255 or less.
+  Added #ifdef's to contrib/examples programs so people don't try
+    to compile them without the minimum required support enabled
+    (suggested by Flavio Medeiros).
+
+Version 1.6.18beta08 [June 30, 2015]
+  Eliminated the final two Coverity defects (insecure temporary file
+    handling in contrib/libtests/pngstest.c; possible overflow of
+    unsigned char in contrib/tools/png-fix-itxt.c). To use the "secure"
+    file handling, define PNG_USE_MKSTEMP, otherwise "tmpfile()" will
+    be used.
+  Removed some unused WEIGHTED_FILTER macros from png.h and pngstruct.h
+
+Version 1.6.18beta09 [July 5, 2015]
+  Removed some useless typecasts from contrib/tools/png-fix-itxt.c
+  Fixed a new signed-unsigned comparison in pngrtran.c (Max Stepin).
+  Replaced arbitrary use of 'extern' with #define PNG_LINKAGE_*.  To
+    preserve API compatibility, the new defines all default to "extern"
+    (requested by Jan Nijtmans).
+
+Version 1.6.18rc01 [July 9, 2015]
+  Belatedly added Mans Rullgard and James Yu to the list of Contributing
+    Authors.
+
+Version 1.6.18rc02 [July 12, 2015]
+  Restored unused FILTER_HEURISTIC macros removed at libpng-1.6.18beta08
+    to png.h to avoid compatibility warnings.
+
+Version 1.6.18rc03 [July 15, 2015]
+  Minor changes to the man page
+
+Version 1.6.18 [July 23, 2015]
+  No changes.
+
+Version 1.6.19beta01 [July 30, 2015]
+  Updated obsolete information about the simplified API macros in the
+    manual pages (Bug report by Arc Riley).
+  Avoid potentially dereferencing NULL info_ptr in png_info_init_3().
+  Rearranged png.h to put the major sections in the same order as
+    in libpng17.
+  Eliminated unused PNG_COST_SHIFT, PNG_WEIGHT_SHIFT, PNG_COST_FACTOR, and
+    PNG_WEIGHT_FACTOR macros.
+  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
+    (Bug report by Viktor Szakats).  Several warnings remain and are
+    unavoidable, where we test for overflow.
+  Fixed potential leak of png_pixels in contrib/pngminus/pnm2png.c
+  Fixed uninitialized variable in contrib/gregbook/rpng2-x.c
+
+Version 1.6.19beta02 [August 19, 2015]
+  Moved config.h.in~ from the "libpng_autotools_files" list to the
+    "libpng_autotools_extra" list in autogen.sh because it was causing a
+    false positive for missing files (bug report by Robert C. Seacord).
+  Removed unreachable "break" statements in png.c, pngread.c, and pngrtran.c
+    to suppress clang warnings (Bug report by Viktor Szakats).
+  Fixed some bad links in the man page.
+  Changed "n bit" to "n-bit" in comments.
+  Added signed/unsigned 16-bit safety net. This removes the dubious
+    0x8000 flag definitions on 16-bit systems. They aren't supported
+    yet the defs *probably* work, however it seems much safer to do this
+    and be advised if anyone, contrary to advice, is building libpng 1.6
+    on a 16-bit system. It also adds back various switch default clauses
+    for GCC; GCC errors out if they are not present (with an appropriately
+    high level of warnings).
+  Safely convert num_bytes to a png_byte in png_set_sig_bytes() (Robert
+    Seacord).
+  Fixed the recently reported 1's complement security issue by replacing
+    the value that is illegal in the PNG spec, in both signed and unsigned
+    values, with 0. Illegal unsigned values (anything greater than or equal
+    to  0x80000000) can still pass through, but since these are not illegal
+    in ANSI-C (unlike 0x80000000 in the signed case) the checking that
+    occurs later can catch them (John Bowler).
+
+Version 1.6.19beta03 [September 26, 2015]
+  Fixed png_save_int_32 when int is not 2's complement (John Bowler).
+  Updated libpng16 with all the recent test changes from libpng17,
+    including changes to pngvalid.c to ensure that the original,
+    distributed, version of contrib/visupng/cexcept.h can be used
+    (John Bowler).
+  pngvalid contains the correction to the use of SAVE/STORE_
+    UNKNOWN_CHUNKS; a bug revealed by changes in libpng 1.7. More
+    tests contain the --strict option to detect warnings and the
+    pngvalid-standard test has been corrected so that it does not
+    turn on progressive-read. There is a separate test which does
+    that. (John Bowler)
+  Also made some signed/unsigned fixes.
+  Make pngstest error limits version specific. Splitting the machine
+    generated error structs out to a file allows the values to be updated
+    without changing pngstest.c itself. Since libpng 1.6 and 1.7 have
+    slightly different error limits this simplifies maintenance. The
+    makepngs.sh script has also been updated to more accurately reflect
+    current problems in libpng 1.7 (John Bowler).
+  Incorporated new test PNG files into make check.  tests/pngstest-*
+    are changed so that the new test files are divided into 8 groups by
+    gamma and alpha channel.  These tests have considerably better code
+    and pixel-value coverage than contrib/pngsuite; however,coverage is
+    still incomplete (John Bowler).
+  Removed the '--strict' in 1.6 because of the double-gamma-correction
+    warning, updated pngstest-errors.h for the errors detected with the
+    new contrib/testspngs PNG test files (John Bowler).
+
+Version 1.6.19beta04 [October 15, 2015]
+  Worked around rgb-to-gray issues in libpng 1.6.  The previous
+    attempts to ignore the errors in the code aren't quite enough to
+    deal with the 'channel selection' encoding added to libpng 1.7; abort.
+    pngvalid.c is changed to drop this encoding in prior versions.
+  Fixed 'pow' macros in pngvalid.c. It is legal for 'pow' to be a
+    macro, therefore the argument list cannot contain preprocessing
+    directives.  Make sure pow is a function where this happens. This is
+    a minimal safe fix, the issue only arises in non-performance-critical
+    code (bug report by Curtis Leach, fix by John Bowler).
+  Added sPLT support to pngtest.c
+
+Version 1.6.19rc01 [October 23, 2015]
+  No changes.
+
+Version 1.6.19rc02 [October 31, 2015]
+  Prevent setting or writing over-length PLTE chunk (Cosmin Truta).
+  Silently truncate over-length PLTE chunk while reading.
+  Libpng incorrectly calculated the output rowbytes when the application
+    decreased either the number of channels or the bit depth (or both) in
+    a user transform.  This was safe; libpng overallocated buffer space
+   (potentially by quite a lot; up to 4 times the amount required) but,
+   from 1.5.4 on, resulted in a png_error (John Bowler).
+
+Version 1.6.19rc03 [November 3, 2015]
+  Fixed some inconsequential cut-and-paste typos in png_set_cHRM_XYZ_fixed().
+  Clarified COPYRIGHT information to state explicitly that versions
+    are derived from previous versions.
+  Removed much of the long list of previous versions from png.h and
+    libpng.3.
+
+Version 1.6.19rc04 [November 5, 2015]
+  Fixed new bug with CRC error after reading an over-length palette
+    (bug report by Cosmin Truta) (CVE-2015-8126).
+
+Version 1.6.19 [November 12, 2015]
+  Cleaned up coding style in png_handle_PLTE().
+
+Version 1.6.20beta01 [November 20, 2015]
+  Avoid potential pointer overflow/underflow in png_handle_sPLT() and
+    png_handle_pCAL() (Bug report by John Regehr).
+
+Version 1.6.20beta02 [November 23, 2015]
+  Fixed incorrect implementation of png_set_PLTE() that uses png_ptr
+    not info_ptr, that left png_set_PLTE() open to the CVE-2015-8126
+    vulnerability.  Fixes CVE-2015-8472.
+
+Version 1.6.20beta03 [November 24, 2015]
+  Backported tests from libpng-1.7.0beta69.
+
+Version 1.6.20rc01 [November 26, 2015]
+  Fixed an error in handling of bad zlib CMINFO field in pngfix, found by
+    American Fuzzy Lop, reported by Brian Carpenter.  inflate() doesn't
+    immediately fault a bad CMINFO field; instead a 'too far back' error
+    happens later (at least some times).  pngfix failed to limit CMINFO to
+    the allowed values but then assumed that window_bits was in range,
+    triggering an assert. The bug is mostly harmless; the PNG file cannot
+    be fixed.
+
+Version 1.6.20rc02 [November 29, 2015]
+  In libpng 1.6 zlib initialization was changed to use the window size
+    in the zlib stream, not a fixed value. This causes some invalid images,
+    where CINFO is too large, to display 'correctly' if the rest of the
+    data is valid.  This provides a workaround for zlib versions where the
+    error arises (ones that support the API change to use the window size
+    in the stream).
+
+Version 1.6.20 [December 3, 2015]
+  No changes.
+
+Version 1.6.21beta01 [December 11, 2015]
+  Fixed syntax "$(command)" in tests/pngstest that some shells other than
+    bash could not parse (Bug report by Nelson Beebe). Use `command` instead.
+
+Version 1.6.21beta02 [December 14, 2015]
+  Moved png_check_keyword() from pngwutil.c to pngset.c
+  Removed LE/BE dependencies in pngvalid, to 'fix' the current problem
+    in the BigEndian tests by not testing it, making the BE code the same
+    as the LE version.
+  Fixes to pngvalid for various reduced build configurations (eliminate unused
+    statics) and a fix for the case in rgb_to_gray when the digitize option
+    reduces graylo to 0, producing a large error.
+
+Version 1.6.21beta03 [December 18, 2015]
+  Widened the 'limit' check on the internally calculated error limits in
+    the 'DIGITIZE' case (the code used prior to 1.7 for rgb_to_gray error
+    checks) and changed the check to only operate in non-release builds
+    (base build type not RC or RELEASE.)
+  Fixed undefined behavior in pngvalid.c, undefined because
+    (png_byte) << shift is undefined if it changes the signed bit
+    (because png_byte is promoted to int). The libpng exported functions
+    png_get_uint_32 and png_get_uint_16 handle this. (Bug reported by
+    David Drysdale as a result of reports from UBSAN in clang 3.8).
+  This changes pngvalid to use BE random numbers; this used to produce
+    errors but these should not be fixed as a result of the previous changes.
+
+Version 1.6.21rc01 [January 4, 2016]
+  In projects/vstudio, combined readme.txt and WARNING into README.txt
+
+Version 1.6.21rc02 [January 7, 2016]
+  Relocated assert() in contrib/tools/pngfix.c, bug found by American
+    Fuzzy Lop, reported by Brian Carpenter.
+  Marked 'limit' UNUSED in transform_range_check().  This only affects
+    release builds.
+
+Version 1.6.21 [January 15, 2016]
+  Worked around a false-positive Coverity issue in pngvalid.c.
+
+Version 1.6.22beta01 [January 23, 2016]
+  Changed PNG_USE_MKSTEMP to __COVERITY__ to select alternate
+    "tmpfile()" implementation in contrib/libtests/pngstest.c
+  Fixed NO_STDIO build of pngunknown.c to skip calling png_init_io()
+    if there is no stdio.h support.
+  Added a png_image_write_to_memory() API and a number of assist macros
+    to allow an application that uses the simplified API write to bypass
+    stdio and write directly to memory.
+  Added some warnings (png.h) and some check code to detect *possible*
+    overflow in the ROW_STRIDE and simplified image SIZE macros.  This
+    disallows image width/height/format that *might* overflow.  This is
+    a quiet API change that limits in-memory image size (uncompressed) to
+    less than 4GByte and image row size (stride) to less than 2GByte.
+  Revised workaround for false-positive Coverity issue in pngvalid.c.
+
+Version 1.6.22beta02 [February 8, 2016]
+  Only use exit(77) in configure builds.
+  Corrected error in PNG_IMAGE_PNG_SIZE_MAX. This new macro underreported
+    the palette size because it failed to take into account that the memory
+    palette has to be expanded to full RGB when it is written to PNG.
+  Updated CMakeLists.txt, added supporting scripts/gen*.cmake.in
+    and test.cmake.in (Roger Leigh).
+  Relaxed limit checks on gamma values in pngrtran.c. As suggested in
+    the comments gamma values outside the range currently permitted
+    by png_set_alpha_mode are useful for HDR data encoding.  These values
+    are already permitted by png_set_gamma so it is reasonable caution to
+    extend the png_set_alpha_mode range as HDR imaging systems are starting
+    to emerge.
+
+Version 1.6.22beta03 [March 9, 2016]
+  Added a common-law trademark notice and export control information
+    to the LICENSE file, png.h, and the man page.
+  Restored "& 0xff" in png_save_uint_16() and png_save_uint_32() that
+    were accidentally removed from libpng-1.6.17.
+  Changed PNG_INFO_cHNK and PNG_FREE_cHNK from 0xnnnn to 0xnnnnU in png.h
+    (Robert C. Seacord).
+  Removed dubious "#if INT_MAX" test from png.h that was added to
+    libpng-1.6.19beta02 (John Bowler).
+  Add ${INCLUDES} in scripts/genout.cmake.in (Bug report by Nixon Kwok).
+  Updated LICENSE to say files in the contrib directory are not
+    necessarily under the libpng license, and that some makefiles have
+    other copyright owners.
+  Added INTEL-SSE2 support (Mike Klein and Matt Sarett, Google, Inc.).
+  Made contrib/libtests/timepng more robust.  The code no longer gives
+    up/fails on invalid PNG data, it just skips it (with error messages).
+    The code no longer fails on PNG files with data beyond IEND.  Options
+    exist to use png_read_png (reading the whole image, not by row) and, in
+    that case, to apply any of the supported transforms.  This makes for
+    more realistic testing; the decoded data actually gets used in a
+    meaningful fashion (John Bowler).
+  Fixed some misleading indentation (Krishnaraj Bhat).
+
+Version 1.6.22beta04 [April 5, 2016]
+  Force GCC compilation to C89 if needed (Dagobert Michelsen).
+  SSE filter speed improvements for bpp=3:
+    memcpy-free implementations of load3() / store3().
+    call load3() only when needed at the end of a scanline.
+
+Version 1.6.22beta05 [April 27, 2016]
+  Added PNG_FAST_FILTERS macro (defined as
+    PNG_FILTER_NONE|PNG_FILTER_SUB|PNG_FILTER_UP).
+  Various fixes for contrib/libtests/timepng.c
+  Moved INTEL-SSE code from pngpriv.h into contrib/intel/intel_sse.patch.
+  Fixed typo (missing underscore) in #define PNG_READ_16_TO_8_SUPPORTED
+    (Bug report by Y.Ohashik).
+
+Version 1.6.22beta06 [May 5, 2016]
+  Rebased contrib/intel_sse.patch.
+  Quieted two Coverity issues in contrib/libtests/timepng.c.
+  Fixed issues with scripts/genout.cmake.in (David Capello, Nixon Kwok):
+    Added support to use multiple directories in ZLIBINCDIR variable,
+    Fixed CMAKE_C_FLAGS with multiple values when genout is compiled on MSVC,
+    Fixed pnglibconf.c compilation on OS X including the sysroot path.
+
+Version 1.6.22rc01 [May 14, 2016]
+  No changes.
+
+Version 1.6.22rc02 [May 16, 2016]
+  Removed contrib/timepng from default build; it does not build on platforms
+    that don't supply clock_gettime().
+
+Version 1.6.22rc03 [May 17, 2016]
+  Restored contrib/timepng to default build but check for the presence
+    of clock_gettime() in configure.ac and Makefile.am.
+
+Version 1.6.22 [May 26, 2016]
+  No changes.
+
+Version 1.6.23beta01 [May 29, 2016]
+  Stop a potential memory leak in png_set_tRNS() (Bug report by Ted Ying).
+  Fixed the progressive reader to handle empty first IDAT chunk properly
+    (patch by Timothy Nikkel).  This bug was introduced in libpng-1.6.0 and
+    only affected the libpng16 branch.
+  Added tests in pngvalid.c to check zero-length IDAT chunks in various
+    positions.  Fixed the sequential reader to handle these more robustly
+    (John Bowler).
+
+Version 1.6.23rc01 [June 2, 2016]
+  Corrected progressive read input buffer in pngvalid.c. The previous version
+    the code invariably passed just one byte at a time to libpng.  The intent
+    was to pass a random number of bytes in the range 0..511.
+  Moved sse2 prototype from pngpriv.h to contrib/intel/intel_sse.patch.
+  Added missing ")" in pngerror.c (Matt Sarrett).
+
+Version 1.6.23rc02 [June 4, 2016]
+  Fixed undefined behavior in png_push_save_buffer(). Do not call
+    memcpy() with a null source, even if count is zero (Leon Scroggins III).
+
+Version 1.6.23 [June 9, 2016]
+  Fixed bad link to RFC2083 in png.5 (Nikola Forro).
+
+Version 1.6.24beta01 [June 11, 2016]
+  Avoid potential overflow of the PNG_IMAGE_SIZE macro.  This macro
+    is not used within libpng, but is used in some of the examples.
+
+Version 1.6.24beta02 [June 23, 2016]
+  Correct filter heuristic overflow handling. This was broken when the
+    write filter code was moved out-of-line; if there is a single filter and
+    the heuristic sum overflows the calculation of the filtered line is not
+    completed.  In versions prior to 1.6 the code was duplicated in-line
+    and the check not performed, so the filter operation completed; however,
+    in the multi-filter case where the sum is performed the 'none' filter would
+    be selected if all the sums overflowed, even if it wasn't in the filter
+    list.  The fix to the first problem is simply to provide PNG_SIZE_MAX as
+    the current lmins sum value; this means the sum can never exceed it and
+    overflows silently.  A reasonable compiler that does choose to inline
+    the code will simply eliminate the sum check.
+  The fix to the second problem is to use high precision arithmetic (this is
+    implemented in 1.7), however a simple safe fix here is to chose the lowest
+    numbered filter in the list from png_set_filter (this only works if the
+    first problem is also fixed) (John Bowler).
+  Use a more efficient absolute value calculation on SSE2 (Matthieu Darbois).
+  Fixed the case where PNG_IMAGE_BUFFER_SIZE can overflow in the application
+    as a result of the application using an increased 'row_stride'; previously
+    png_image_finish_read only checked for overflow on the base calculation of
+    components.  (I.e. it checked for overflow of a 32-bit number on the total
+    number of pixel components in the output format, not the possibly padded row
+    length and not the number of bytes, which for linear formats is twice the
+    number of components.)
+  MSVC does not like '-(unsigned)', so replaced it with 0U-(unsigned)
+  MSVC does not like (uInt) = -(unsigned) (i.e. as an initializer), unless
+    the conversion is explicitly invoked by a cast.
+  Put the SKIP definition in the correct place. It needs to come after the
+    png.h include (see all the other .c files in contrib/libtests) because it
+    depends on PNG_LIBPNG_VER.
+  Removed the three compile warning options from the individual project
+    files into the zlib.props globals.  It increases the warning level from 4
+    to All and adds a list of the warnings that need to be turned off.  This is
+    semi-documentary; the intent is to tell libpng users which warnings have
+    been examined and judged non-fixable at present.  The warning about
+    structure padding is fixable, but it would be a significant change (moving
+    structure members around).
+
+Version 1.6.24beta03 [July 4, 2016]
+  Optimized absolute value calculation in filter selection, similar to
+    code in the PAETH decoder in pngrutil.c. Build with PNG_USE_ABS to
+    use this.
+  Added pngcp to the build together with a pngcp.dfa configuration test.
+  Added high resolution timing to pngcp.
+  Added "Common linking failures" section to INSTALL.
+  Relocated misplaced #endif in png.c sRGB profile checking.
+  Fixed two Coverity issues in pngcp.c.
+
+Version 1.6.24beta04 [July 8, 2016]
+  Avoid filter-selection heuristic sum calculations in cases where only one
+    filter is a candidate for selection. This trades off code size (added
+    private png_setup_*_row_only() functions) for speed.
+
+Version 1.6.24beta05 [July 13, 2016]
+  Fixed some indentation to comply with our coding style.
+  Added contrib/tools/reindent.
+
+Version 1.6.24beta06 [July 18, 2016]
+  Fixed more indentation to comply with our coding style.
+  Eliminated unnecessary tests of boolean png_isaligned() vs 0.
+
+Version 1.6.24rc01 [July 25, 2016]
+  No changes.
+
+Version 1.6.24rc02 [August 1, 2016]
+  Conditionally compile SSE2 headers in contrib/intel/intel_sse.patch
+  Conditionally compile png_decompress_chunk().
+
+Version 1.6.24rc03 [August 2, 2016]
+  Conditionally compile ARM_NEON headers in pngpriv.h
+  Updated contrib/intel/intel_sse.patch
+
+Version 1.6.24[August 4, 2016]
+  No changes.
+
+Version 1.6.25beta01 [August 12, 2016]
+  Reject oversized iCCP profile immediately.
+  Cleaned up PNG_DEBUG compile of pngtest.c.
+  Conditionally compile png_inflate().
+
+Version 1.6.25beta02 [August 18, 2016]
+  Don't install pngcp; it conflicts with pngcp in the pngtools package.
+  Minor editing of INSTALL, (whitespace, added copyright line)
+
+Version 1.6.25rc01 [August 24, 2016]
+  No changes.
+
+Version 1.6.25rc02 [August 29, 2016]
+  Added MIPS support (Mandar Sahastrabuddhe <Mandar.Sahastrabuddhe@imgtec.com>).
+  Only the UP filter is currently implemented.
+
+Version 1.6.25rc03 [August 29, 2016]
+  Rebased contrib/intel/intel_sse.patch after the MIPS implementation.
+
+Version 1.6.25rc04 [August 30, 2016]
+  Added MIPS support for SUB, AVG, and PAETH filters (Mandar Sahastrabuddhe).
+
+Version 1.6.25rc05 [August 30, 2016]
+  Rebased contrib/intel/intel_sse.patch after the MIPS implementation update..
+
+Version 1.6.25 [September 1, 2016]
+  No changes.
+
+Version 1.6.26beta01 [September 26, 2016]
+  Fixed handling zero length IDAT in pngfix (bug report by Agostino Sarubbo,
+    bugfix by John Bowler).
+  Do not issue a png_error() on read in png_set_pCAL() because png_handle_pCAL
+    has allocated memory that libpng needs to free.
+  Conditionally compile png_set_benign_errors() in pngread.c and pngtest.c
+  Issue a png_benign_error instead of a png_error on ADLER32 mismatch
+    while decoding compressed data chunks.
+  Changed PNG_ZLIB_VERNUM to ZLIB_VERNUM in pngpriv.h, pngstruct.h, and
+    pngrutil.c.
+  If CRC handling of critical chunks has been set to PNG_CRC_QUIET_USE,
+    ignore the ADLER32 checksum in the IDAT chunk as well as the chunk CRCs.
+  Issue png_benign_error() on ADLER32 checksum mismatch instead of png_error().
+  Add tests/badcrc.png and tests/badadler.png to tests/pngtest.
+  Merged pngtest.c with libpng-1.7.0beta84/pngtest.c
+
+Version 1.6.26beta02 [October 1, 2016]
+  Updated the documentation about CRC and ADLER32 handling.
+  Quieted 117 warnings from clang-3.8 in pngtrans.c, pngread.c,
+     pngwrite.c, pngunknown.c, and pngvalid.c.
+  Quieted 58 (out of 144) -Wconversion compiler warnings by changing
+    flag definitions in pngpriv.h from 0xnnnn to 0xnnnnU and trivial changes
+    in png.c, pngread.c, and pngwutil.c.
+
+Version 1.6.26beta03 [October 2, 2016]
+  Removed contrib/libtests/*.orig and *.rej that slipped into the tarballs.
+  Quieted the 86 remaining -Wconversion compiler warnings by
+    revising the png_isaligned() macro and trivial changes in png.c,
+    pngerror.c, pngget.c, pngmem.c, pngset.c, pngrtran.c, pngrutil.c,
+    pngwtran.c, pngwrite.c, and pngwutil.c.
+
+Version 1.6.26beta04 [October 3, 2016]
+  Quieted (bogus?) clang warnings about "absolute value has no effect"
+    when PNG_USE_ABS is defined.
+  Fixed offsets in contrib/intel/intel_sse.patch
+
+Version 1.6.26beta05 [October 6, 2016]
+  Changed integer constant 4294967294 to unsigned 4294967294U in pngconf.h
+    to avoid a signed/unsigned compare in the preprocessor.
+
+Version 1.6.26beta06 [October 7, 2016]
+  Use zlib-1.2.8.1 inflateValidate() instead of inflateReset2() to
+    optionally avoid ADLER32 evaluation.
+
+Version 1.6.26rc01 [October 12, 2016]
+  No changes.
+
+Version 1.6.26 [October 20, 2016]
+  Cosmetic change, "ptr != 0" to "ptr != NULL" in png.c and pngrutil.c
+  Despammed email addresses (replaced "@" with " at ").
+
+Version 1.6.27beta01 [November 2, 2016]
+  Restrict the new ADLER32-skipping to IDAT chunks.  It broke iCCP chunk
+    handling: an erroneous iCCP chunk would throw a png_error and reject the
+    entire PNG image instead of rejecting just the iCCP chunk with a warning,
+    if built with zlib-1.2.8.1.
+
+Version 1.6.27rc01 [December 27, 2016]
+  Control ADLER32 checking with new PNG_IGNORE_ADLER32 option. Fixes
+    an endless loop when handling erroneous ADLER32 checksums; bug
+    introduced in libpng-1.6.26.
+  Removed the use of a macro containing the pre-processor 'defined'
+    operator.  It is unclear whether this is valid; a macro that
+    "generates" 'defined' is not permitted, but the use of the word
+    "generates" within the C90 standard seems to imply more than simple
+    substitution of an expression itself containing a well-formed defined
+    operation.
+  Added ARM support to CMakeLists.txt (Andreas Franek).
+
+Version 1.6.27 [December 29, 2016]
+  Fixed a potential null pointer dereference in png_set_text_2() (bug report
+    and patch by Patrick Keshishian, CVE-2016-10087).
+
+Version 1.6.28rc01 [January 3, 2017]
+  Fixed arm/aarch64 detection in CMakeLists.txt (Gianfranco Costamagna).
+  Added option to Cmake build allowing a custom location of zlib to be
+    specified in a scenario where libpng is being built as a subproject
+    alongside zlib by another project (Sam Serrels).
+  Changed png_ptr->options from a png_byte to png_uint_32, to accommodate
+    up to 16 options.
+
+Version 1.6.28rc02 [January 4, 2017]
+  Added "include(GNUInstallDirs)" to CMakeLists.txt (Gianfranco Costamagna).
+  Moved SSE2 optimization code into the main libpng source directory.
+    Configure libpng with "configure --enable-intel-sse" or compile
+    libpng with "-DPNG_INTEL_SSE" in CPPFLAGS to enable it.
+
+Version 1.6.28rc03 [January 4, 2017]
+  Backed out the SSE optimization and last CMakeLists.txt to allow time for QA.
+
+Version 1.6.28 [January 5, 2017]
+  No changes.
+
+Version 1.6.29beta01 [January 12, 2017]
+  Readded "include(GNUInstallDirs)" to CMakeLists.txt (Gianfranco Costamagna).
+  Moved SSE2 optimization code into the main libpng source directory.
+    Configure libpng with "configure --enable-intel-sse" or compile
+    libpng with "-DPNG_INTEL_SSE" in CPPFLAGS to enable it.
+  Simplified conditional compilation in pngvalid.c, for AIX (Michael Felt).
+
+Version 1.6.29beta02 [February 22, 2017]
+  Avoid conditional directives that break statements in pngrutil.c (Romero
+    Malaquias)
+  The contrib/examples/pngtopng.c recovery code was in the wrong "if"
+    branches; the comments were correct.
+  Added code for PowerPC VSX optimisation (Vadim Barkov).
+
+Version 1.6.29beta03 [March 1, 2017]
+  Avoid potential overflow of shift operations in png_do_expand() (Aaron Boxer).
+  Change test ZLIB_VERNUM >= 0x1281 to ZLIB_VERNUM >= 0x1290 in pngrutil.c
+    because Solaris 11 distributes zlib-1.2.8.f that is older than 1.2.8.1,
+    as suggested in zlib FAQ, item 24.
+  Suppress clang warnings about implicit sign changes in png.c
+
+Version 1.6.29 [March 16, 2017]
+  No changes.
+
+Version 1.6.30beta01 [April 1, 2017]
+  Added missing "$(CPPFLAGS)" to the compile line for c.pic.o in
+    makefile.linux and makefile.solaris-x86 (Cosmin).
+  Revised documentation of png_get_error_ptr() in the libpng manual.
+  Silence clang -Wcomma and const drop warnings (Viktor Szakats).
+  Update Sourceforge URLs in documentation (https instead of http).
+
+Version 1.6.30beta02 [April 22, 2017]
+  Document need to check for integer overflow when allocating a pixel
+    buffer for multiple rows in contrib/gregbook, contrib/pngminus,
+    example.c, and in the manual (suggested by Jaeseung Choi). This
+    is similar to the bug reported against pngquant in CVE-2016-5735.
+  Removed reference to the obsolete PNG_SAFE_LIMITS macro in the documentation.
+
+Version 1.6.30beta03 [May 22, 2017]
+  Check for integer overflow in contrib/visupng and contrib/tools/genpng.
+  Do not double evaluate CMAKE_SYSTEM_PROCESSOR in CMakeLists.txt.
+  Test CMAKE_HOST_WIN32 instead of WIN32 in CMakeLists.txt.
+  Fix some URL in documentation.
+
+Version 1.6.30beta04 [June 7, 2017]
+  Avoid writing an empty IDAT when the last IDAT exactly fills the
+    compression buffer (bug report by Brian Baird). This bug was
+    introduced in libpng-1.6.0.
+
+Version 1.6.30rc01 [June 14, 2017]
+  No changes.
+
+Version 1.6.30rc02 [June 25, 2017]
+  Update copyright year in pnglibconf.h, make ltmain.sh executable.
+  Add a reference to the libpng.download site in README.
+
+Version 1.6.30 [June 28, 2017]
+  No changes.
+
+Version 1.6.31beta01 [July 5, 2017]
+  Guard the definition of _POSIX_SOURCE in pngpriv.h (AIX already defines it;
+    bug report by Michael Felt).
+  Revised pngpriv.h to work around failure to compile arm/filter_neon.S
+    ("typedef" directive is unrecognized by the assembler). The problem
+    was introduced in libpng-1.6.30beta01.
+  Added "Requires: zlib" to libpng.pc.in (Pieter Neerincx).
+  Added special case for FreeBSD in arm/filter_neon.S (Maya Rashish).
+
+Version 1.6.31beta02 [July 8, 2017]
+  Added instructions for disabling hardware optimizations in INSTALL.
+  Added "--enable-hardware-optimizations" configuration flag to enable
+    or disable all hardware optimizations with one flag.
+
+Version 1.6.31beta03 [July 9, 2017]
+  Updated CMakeLists.txt to add INTEL_SSE and MIPS_MSA platforms.
+  Changed "int" to "png_size_t" in intel/filter_sse2.c to prevent
+    possible integer overflow (Bug report by John Bowler).
+  Quieted "declaration after statement" warnings in intel/filter_sse2.c.
+  Added scripts/makefile-linux-opt, which has hardware optimizations enabled.
+
+Version 1.6.31beta04 [July 11, 2017]
+  Removed one of the GCC-7.1.0 'strict-overflow' warnings that result when
+    integers appear on both sides of a compare.  Worked around the others by
+    forcing the strict-overflow setting in the relevant functions to a level
+    where they are not reported (John Bowler).
+  Changed "FALL THROUGH" comments to "FALLTHROUGH" because GCC doesn't like
+    the space.
+  Worked around some C-style casts from (void*) because g++ 5.4.0 objects
+    to them.
+  Increased the buffer size for 'sprint' to pass the gcc 7.1.0 'sprint
+    overflow' check that is on by default with -Wall -Wextra.
+
+Version 1.6.31beta05 [July 13, 2017]
+  Added eXIf chunk support.
+
+Version 1.6.31beta06 [July 17, 2017]
+  Added a minimal eXIf chunk (with Orientation and FocalLengthIn35mmFilm
+    tags) to pngtest.png.
+
+Version 1.6.31beta07 [July 18, 2017]
+  Revised the eXIf chunk in pngtest.png to fix "Bad IFD1 Directory" warning.
+
+Version 1.6.31rc01 [July 19, 2017]
+  No changes.
+
+Version 1.6.31rc02 [July 25, 2017]
+  Fixed typo in example.c (png_free_image should be png_image_free) (Bug
+    report by John Smith)
+
+Version 1.6.31 [July 27, 2017]
+  No changes.
+
+Version 1.6.32beta01 [July 31, 2017]
+  Avoid possible NULL dereference in png_handle_eXIf when benign_errors
+    are allowed. Avoid leaking the input buffer "eXIf_buf".
+  Eliminated png_ptr->num_exif member from pngstruct.h and added num_exif
+    to arguments for png_get_eXIf() and png_set_eXIf().
+  Added calls to png_handle_eXIf(() in pngread.c and png_write_eXIf() in
+    pngwrite.c, and made various other fixes to png_write_eXIf().
+  Changed name of png_get_eXIF and png_set_eXIf() to png_get_eXIf_1() and
+    png_set_eXIf_1(), respectively, to avoid breaking API compatibility
+    with libpng-1.6.31.
+
+Version 1.6.32beta02 [August 1, 2017]
+  Updated contrib/libtests/pngunknown.c with eXIf chunk.
+
+Version 1.6.32beta03 [August 2, 2017]
+  Initialized btoa[] in pngstest.c
+  Stop memory leak when returning from png_handle_eXIf() with an error
+    (Bug report from the OSS-fuzz project).
+
+Version 1.6.32beta04 [August 2, 2017]
+  Replaced local eXIf_buf with info_ptr->eXIf_buf in png_handle_eXIf().
+  Update libpng.3 and libpng-manual.txt about eXIf functions.
+
+Version 1.6.32beta05 [August 2, 2017]
+  Restored png_get_eXIf() and png_set_eXIf() to maintain API compatibility.
+
+Version 1.6.32beta06 [August 2, 2017]
+  Removed png_get_eXIf_1() and png_set_eXIf_1().
+
+Version 1.6.32beta07 [August 3, 2017]
+  Check length of all chunks except IDAT against user limit to fix an
+    OSS-fuzz issue (Fixes CVE-2017-12652).
+
+Version 1.6.32beta08 [August 3, 2017]
+  Check length of IDAT against maximum possible IDAT size, accounting
+    for height, rowbytes, interlacing and zlib/deflate overhead.
+  Restored png_get_eXIf_1() and png_set_eXIf_1(), because strlen(eXIf_buf)
+    does not work (the eXIf chunk data can contain zeroes).
+
+Version 1.6.32beta09 [August 3, 2017]
+  Require cmake-2.8.8 in CMakeLists.txt. Revised symlink creation,
+    no longer using deprecated cmake LOCATION feature (Clifford Yapp).
+  Fixed five-byte error in the calculation of IDAT maximum possible size.
+
+Version 1.6.32beta10 [August 5, 2017]
+  Moved chunk-length check into a png_check_chunk_length() private
+    function (Suggested by Max Stepin).
+  Moved bad pngs from tests to contrib/libtests/crashers
+  Moved testing of bad pngs into a separate tests/pngtest-badpngs script
+  Added the --xfail (expected FAIL) option to pngtest.c. It writes XFAIL
+    in the output but PASS for the libpng test.
+  Require cmake-3.0.2 in CMakeLists.txt (Clifford Yapp).
+  Fix "const" declaration info_ptr argument to png_get_eXIf_1() and the
+    num_exif argument to png_get_eXIf_1() (Github Issue 171).
+
+Version 1.6.32beta11 [August 7, 2017]
+  Added "eXIf" to "chunks_to_ignore[]" in png_set_keep_unknown_chunks().
+  Added huge_IDAT.png and empty_ancillary_chunks.png to testpngs/crashers.
+  Make pngtest --strict, --relax, --xfail options imply -m (multiple).
+  Removed unused chunk_name parameter from png_check_chunk_length().
+  Relocated setting free_me for eXIf data, to stop an OSS-fuzz leak.
+  Initialize profile_header[] in png_handle_iCCP() to fix OSS-fuzz issue.
+  Initialize png_ptr->row_buf[0] to 255 in png_read_row() to fix OSS-fuzz UMR.
+  Attempt to fix a UMR in png_set_text_2() to fix OSS-fuzz issue.
+  Increase minimum zlib stream from 9 to 14 in png_handle_iCCP(), to account
+    for the minimum 'deflate' stream, and relocate the test to a point
+    after the keyword has been read.
+  Check that the eXIf chunk has at least 2 bytes and begins with "II" or "MM".
+
+Version 1.6.32rc01 [August 18, 2017]
+  Added a set of "huge_xxxx_chunk.png" files to contrib/testpngs/crashers,
+    one for each known chunk type, with length = 2GB-1.
+  Check for 0 return from png_get_rowbytes() and added some (size_t) typecasts
+    in contrib/pngminus/*.c to stop some Coverity issues (162705, 162706,
+    and 162707).
+  Renamed chunks in contrib/testpngs/crashers to avoid having files whose
+    names differ only in case; this causes problems with some platforms
+    (github issue #172).
+
+Version 1.6.32rc02 [August 22, 2017]
+  Added contrib/oss-fuzz directory which contains files used by the oss-fuzz
+    project (https://github.com/google/oss-fuzz/tree/master/projects/libpng).
+
+Version 1.6.32 [August 24, 2017]
+  No changes.
+
+Version 1.6.33beta01 [August 28, 2017]
+  Added PNGMINUS_UNUSED macro to contrib/pngminus/p*.c and added missing
+    parenthesis in contrib/pngminus/pnm2png.c (bug report by Christian Hesse).
+  Fixed off-by-one error in png_do_check_palette_indexes() (Bug report
+    by Mick P., Source Forge Issue #269).
+
+Version 1.6.33beta02 [September 3, 2017]
+  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
+    to fix shortlived oss-fuzz issue 3234.
+  Compute a larger limit on IDAT because some applications write a deflate
+    buffer for each row (Bug report by Andrew Church).
+  Use current date (DATE) instead of release-date (RDATE) in last
+    changed date of contrib/oss-fuzz files.
+  Enabled ARM support in CMakeLists.txt (Bernd Kuhls).
+
+Version 1.6.33beta03 [September 14, 2017]
+  Fixed incorrect typecast of some arguments to png_malloc() and
+    png_calloc() that were png_uint_32 instead of png_alloc_size_t
+    (Bug report by "irwir" in Github libpng issue #175).
+  Use pnglibconf.h.prebuilt when building for ANDROID with cmake (Github
+    issue 162, by rcdailey).
+
+Version 1.6.33rc01 [September 20, 2017]
+  Initialize memory allocated by png_inflate to zero, using memset, to
+    stop an oss-fuzz "use of uninitialized value" detection in png_set_text_2()
+    due to truncated iTXt or zTXt chunk.
+  Initialize memory allocated by png_read_buffer to zero, using memset, to
+    stop an oss-fuzz "use of uninitialized value" detection in
+    png_icc_check_tag_table() due to truncated iCCP chunk.
+  Removed a redundant test (suggested by "irwir" in Github issue #180).
+
+Version 1.6.33rc02 [September 23, 2017]
+  Added an interlaced version of each file in contrib/pngsuite.
+  Relocate new memset() call in pngrutil.c.
+  Removed more redundant tests (suggested by "irwir" in Github issue #180).
+  Add support for loading images with associated alpha in the Simplified
+    API (Samuel Williams).
+
+Version 1.6.33 [September 28, 2017]
+  Revert contrib/oss-fuzz/libpng_read_fuzzer.cc to libpng-1.6.32 state.
+  Initialize png_handler.row_ptr in contrib/oss-fuzz/libpng_read_fuzzer.cc
+  Add end_info structure and png_read_end() to the libpng fuzzer.
+
+Version 1.6.34 [September 29, 2017]
+  Removed contrib/pngsuite/i*.png; some of them caused test failures.
+
+Version 1.6.35beta01 [March 6, 2018]
+  Restored 21 of the contrib/pngsuite/i*.png, which do not cause test
+    failures. Placed the remainder in contrib/pngsuite/interlaced/i*.png.
+  Added calls to png_set_*() transforms commonly used by browsers to
+    the fuzzer.
+  Removed some unnecessary brackets in pngrtran.c
+  Fixed miscellaneous typos (Patch by github user "luzpaz").
+  Change "ASM C" to "C ASM" in CMakeLists.txt
+  Fixed incorrect handling of bKGD chunk in sub-8-bit files (Cosmin)
+  Added hardware optimization directories to zip and 7z distributions.
+  Fixed incorrect bitmask for options.
+  Fixed many spelling typos.
+
+Version 1.6.35beta02 [March 28, 2018]
+  Make png_get_iCCP consistent with man page (allow compression-type argument
+  to be NULL, bug report by Lenard Szolnoki).
+
+Version 1.6.35 [July 15, 2018]
+  Replaced the remaining uses of png_size_t with size_t (Cosmin)
+  Fixed the calculation of row_factor in png_check_chunk_length
+    (reported by Thuan Pham in SourceForge issue #278)
+  Added missing parentheses to a macro definition
+    (suggested by "irwir" in GitHub issue #216)
+
+Version 1.6.36 [December 1, 2018]
+  Optimized png_do_expand_palette for ARM processors.
+  Improved performance by around 10-22% on a recent ARM Chromebook.
+    (Contributed by Richard Townsend, ARM Holdings)
+  Fixed manipulation of machine-specific optimization options.
+    (Contributed by Vicki Pfau)
+  Used memcpy instead of manual pointer arithmetic on Intel SSE2.
+    (Contributed by Samuel Williams)
+  Fixed build errors with MSVC on ARM64.
+    (Contributed by Zhijie Liang)
+  Fixed detection of libm in CMakeLists.
+    (Contributed by Cameron Cawley)
+  Fixed incorrect creation of pkg-config file in CMakeLists.
+    (Contributed by Kyle Bentley)
+  Fixed the CMake build on Windows MSYS by avoiding symlinks.
+  Fixed a build warning on OpenBSD.
+    (Contributed by Theo Buehler)
+  Fixed various typos in comments.
+    (Contributed by "luz.paz")
+  Raised the minimum required CMake version from 3.0.2 to 3.1.
+  Removed yet more of the vestigial support for pre-ANSI C compilers.
+  Removed ancient makefiles for ancient systems that have been broken
+    across all previous libpng-1.6.x versions.
+  Removed the Y2K compliance statement and the export control
+    information.
+  Applied various code style and documentation fixes.
+
+Version 1.6.37 [April 14, 2019]
+  Fixed a use-after-free vulnerability (CVE-2019-7317) in png_image_free.
+  Fixed a memory leak in the ARM NEON implementation of png_do_expand_palette.
+  Fixed a memory leak in pngtest.c.
+  Fixed two vulnerabilities (CVE-2018-14048, CVE-2018-14550) in
+    contrib/pngminus; refactor.
+  Changed the license of contrib/pngminus to MIT; refresh makefile and docs.
+    (Contributed by Willem van Schaik)
+  Fixed a typo in the libpng license v2.
+    (Contributed by Miguel Ojeda)
+  Added makefiles for AddressSanitizer-enabled builds.
+  Cleaned up various makefiles.
+
+Version 1.6.38 [September 14, 2022]
+  Added configurations and scripts for continuous integration.
+  Fixed various errors in the handling of tRNS, hIST and eXIf.
+  Implemented many stability improvements across all platforms.
+  Updated the internal documentation.
+
+Version 1.6.39 [November 20, 2022]
+  Changed the error handler of oversized chunks (i.e. larger than
+    PNG_USER_CHUNK_MALLOC_MAX) from png_chunk_error to png_benign_error.
+  Fixed a buffer overflow error in contrib/tools/pngfix.
+  Fixed a memory leak (CVE-2019-6129) in contrib/tools/pngcp.
+  Disabled the ARM Neon optimizations by default in the CMake file,
+    following the default behavior of the configure script.
+  Allowed configure.ac to work with the trunk version of autoconf.
+  Removed the support for "install" targets from the legacy makefiles;
+    removed the obsolete makefile.cegcc.
+  Cleaned up the code and updated the internal documentation.
+
+Version 1.6.40 [June 21, 2023]
+  Fixed the eXIf chunk multiplicity checks.
+  Fixed a memory leak in pCAL processing.
+  Corrected the validity report about tRNS inside png_get_valid().
+  Fixed various build issues on *BSD, Mac and Windows.
+  Updated the configurations and the scripts for continuous integration.
+  Cleaned up the code, the build scripts, and the documentation.
+
+Version 1.6.41 [January 24, 2024]
+  Added SIMD-optimized code for the LoongArch LSX hardware.
+    (Contributed by GuXiWei, JinBo and ZhangLixia)
+  Fixed the run-time discovery of MIPS MSA hardware.
+    (Contributed by Sui Jingfeng)
+  Fixed an off-by-one error in the function png_do_check_palette_indexes(),
+    which failed to recognize errors that might have existed in the first
+    column of a broken palette-encoded image. This was a benign regression
+    accidentally introduced in libpng-1.6.33. No pixel was harmed.
+    (Contributed by Adam Richter; reviewed by John Bowler)
+  Fixed, improved and modernized the contrib/pngminus programs, i.e.,
+    png2pnm.c and pnm2png.c
+  Removed old and peculiar portability hacks that were meant to silence
+    warnings issued by gcc version 7.1 alone.
+    (Contributed by John Bowler)
+  Fixed and modernized the CMake file, and raised the minimum required
+    CMake version from 3.1 to 3.6.
+    (Contributed by Clinton Ingram, Timothy Lyanguzov, Tyler Kropp, et al.)
+  Allowed the configure script to disable the building of auxiliary tools
+    and tests, thus catching up with the CMake file.
+    (Contributed by Carlo Bramini)
+  Fixed a build issue on Mac.
+    (Contributed by Zixu Wang)
+  Moved the Autoconf macro files to scripts/autoconf.
+  Moved the CMake files (except for the main CMakeLists.txt) to
+    scripts/cmake and moved the list of their contributing authors to
+    scripts/cmake/AUTHORS.md
+  Updated the CI configurations and scripts.
+  Relicensed the CI scripts to the MIT License.
+  Improved the test coverage.
+    (Contributed by John Bowler)
+
+Version 1.6.42 [January 29, 2024]
+  Fixed the implementation of the macro function png_check_sig().
+    This was an API regression, introduced in libpng-1.6.41.
+    (Reported by Matthieu Darbois)
+  Fixed and updated the libpng manual.
+
+Version 1.6.43 [February 23, 2024]
+  Fixed the row width check in png_check_IHDR().
+    This corrected a bug that was specific to the 16-bit platforms,
+    and removed a spurious compiler warning from the 64-bit builds.
+    (Reported by Jacek Caban; fixed by John Bowler)
+  Added eXIf chunk support to the push-mode reader in pngpread.c.
+    (Contributed by Chris Blume)
+  Added contrib/pngexif for the benefit of the users who would like
+    to inspect the content of eXIf chunks.
+  Added contrib/conftest/basic.dfa, a basic build-time configuration.
+    (Contributed by John Bowler)
+  Fixed a preprocessor condition in pngread.c that broke build-time
+    configurations like contrib/conftest/pngcp.dfa.
+    (Contributed by John Bowler)
+  Added CMake build support for LoongArch LSX.
+    (Contributed by GuXiWei)
+  Fixed a CMake build error that occurred under a peculiar state of the
+    dependency tree. This was a regression introduced in libpng-1.6.41.
+    (Contributed by Dan Rosser)
+  Marked the installed libpng headers as system headers in CMake.
+    (Contributed by Benjamin Buch)
+  Updated the build support for RISCOS.
+    (Contributed by Cameron Cawley)
+  Updated the makefiles to allow cross-platform builds to initialize
+    conventional make variables like AR and ARFLAGS.
+  Added various improvements to the CI scripts in areas like version
+    consistency verification and text linting.
+  Added version consistency verification to pngtest.c also.
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net.
+Subscription is required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe.
Index: /trunk/src/libs/libpng-1.6.45/CMakeLists.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/CMakeLists.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/CMakeLists.txt	(revision 107811)
@@ -0,0 +1,1133 @@
+
+# CMakeLists.txt - CMake lists for libpng
+#
+# Copyright (c) 2018-2024 Cosmin Truta.
+# Copyright (c) 2007-2018 Glenn Randers-Pehrson.
+# Originally written by Christian Ehrlicher, 2007.
+#
+# Use, modification and distribution are subject to
+# the same licensing terms and conditions as libpng.
+# Please see the copyright notice in png.h or visit
+# http://libpng.org/pub/png/src/libpng-LICENSE.txt
+#
+# For copyright and licensing purposes, please see
+# the accompanying file scripts/cmake/AUTHORS.md
+#
+# SPDX-License-Identifier: libpng-2.0
+
+cmake_minimum_required(VERSION 3.6)
+
+set(PNGLIB_MAJOR 1)
+set(PNGLIB_MINOR 6)
+set(PNGLIB_REVISION 43)
+set(PNGLIB_SUBREVISION 0)
+#set(PNGLIB_SUBREVISION "git")
+set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_REVISION})
+set(PNGLIB_ABI_VERSION ${PNGLIB_MAJOR}${PNGLIB_MINOR})
+set(PNGLIB_SHARED_VERSION ${PNGLIB_ABI_VERSION}.${PNGLIB_REVISION}.${PNGLIB_SUBREVISION})
+
+project(libpng
+        VERSION ${PNGLIB_VERSION}
+        LANGUAGES C ASM)
+
+if(POLICY CMP0074)
+  # Allow find_package() to use the ZLIB_ROOT variable, if available.
+  cmake_policy(SET CMP0074 NEW)
+endif()
+
+include(CheckCSourceCompiles)
+include(GNUInstallDirs)
+
+# Allow the users to specify an application-specific API prefix for libpng
+# vendoring purposes. A standard libpng build should have no such prefix.
+set(PNG_PREFIX ""
+    CACHE STRING "Prefix to prepend to the API function names")
+
+# Allow the users to override the postfix appended to debug library file names.
+# Previously, we used to set CMAKE_DEBUG_POSTFIX globally. That variable should
+# not be cached, however, because doing so would affect all projects processed
+# after libpng, in unexpected and undesirable ways.
+set(PNG_DEBUG_POSTFIX "d"
+    CACHE STRING "Postfix to append to library file names under the Debug configuration")
+
+# Allow the users to import their own extra configuration settings.
+set(DFA_XTRA ""
+    CACHE FILEPATH "File containing extra configuration settings")
+
+# Allow the users to switch on/off various library build types.
+option(PNG_SHARED "Build libpng as a shared library" ON)
+option(PNG_STATIC "Build libpng as a static library" ON)
+if(APPLE)
+  option(PNG_FRAMEWORK "Build libpng as a framework bundle" ON)
+endif()
+
+# Allow the users to switch on/off the auxiliary build and test artifacts.
+# These artifacts are NOT part of libpng proper, and are subject to change
+# at any time.
+option(PNG_TESTS "Build the libpng tests" ON)
+
+# Same as above, but for the third-party tools.
+# Although these tools are targetted at development environments only,
+# the users are allowed to override the option to build by default.
+if (ANDROID OR IOS)
+  option(PNG_TOOLS "Build the libpng tools" OFF)
+else()
+  option(PNG_TOOLS "Build the libpng tools" ON)
+endif()
+
+# Maintain backwards compatibility with the deprecated option PNG_EXECUTABLES.
+option(PNG_EXECUTABLES "[Deprecated; please use PNG_TOOLS]" ON)
+if(NOT PNG_EXECUTABLES)
+  message(DEPRECATION "The option PNG_EXECUTABLES has been deprecated in favour of PNG_TOOLS")
+  if(PNG_TOOLS)
+    message(AUTHOR_WARNING
+            "Setting PNG_TOOLS to ${PNG_EXECUTABLES}, to stay compatible with PNG_EXECUTABLES")
+    set(PNG_TOOLS "${PNG_EXECUTABLES}")
+  endif()
+endif()
+
+# Allow the users to configure various compilation options.
+option(PNG_DEBUG "Enable debug output" OFF)
+option(PNG_HARDWARE_OPTIMIZATIONS "Enable hardware optimizations" ON)
+
+# Allow the users to specify a custom location of zlib.
+# This option is deprecated, and no longer needed with CMake 3.12 and newer.
+# Under the CMake policy CMP0074, if zlib is being built alongside libpng as a
+# subproject, its location can be passed on to CMake via the ZLIB_ROOT variable.
+option(PNG_BUILD_ZLIB "Custom zlib location, else find_package is used" OFF)
+if(NOT PNG_BUILD_ZLIB)
+  find_package(ZLIB REQUIRED)
+elseif(POLICY CMP0074)
+  if("x${ZLIB_ROOT}" STREQUAL "x")
+    message(DEPRECATION
+            "The option PNG_BUILD_ZLIB has been deprecated; please use ZLIB_ROOT instead")
+  else()
+    message(SEND_ERROR
+            "The option PNG_BUILD_ZLIB=${PNG_BUILD_ZLIB} and "
+            "the variable ZLIB_ROOT=\"${ZLIB_ROOT}\" are mutually exclusive")
+  endif()
+endif()
+
+if(UNIX AND NOT APPLE AND NOT BEOS AND NOT HAIKU AND NOT EMSCRIPTEN)
+  find_library(M_LIBRARY m)
+  if(M_LIBRARY)
+    set(M_LIBRARY m)
+  else()
+    set(M_LIBRARY "")
+  endif()
+else()
+  # libm is not available or not needed.
+endif()
+
+# CMake currently sets CMAKE_SYSTEM_PROCESSOR to one of x86_64 or arm64 on macOS,
+# based upon the OS architecture, not the target architecture. As such, we need
+# to check CMAKE_OSX_ARCHITECTURES to identify which hardware-specific flags to
+# enable. Note that this will fail if you attempt to build a universal binary in
+# a single CMake invocation.
+if (APPLE AND CMAKE_OSX_ARCHITECTURES)
+  set(TARGET_ARCH ${CMAKE_OSX_ARCHITECTURES})
+else()
+  set(TARGET_ARCH ${CMAKE_SYSTEM_PROCESSOR})
+endif()
+
+if(PNG_HARDWARE_OPTIMIZATIONS)
+
+# Set definitions and sources for ARM.
+if(TARGET_ARCH MATCHES "^(ARM|arm|aarch)")
+  if(TARGET_ARCH MATCHES "^(ARM64|arm64|aarch64)")
+    set(PNG_ARM_NEON_POSSIBLE_VALUES on off)
+    set(PNG_ARM_NEON "on"
+        CACHE STRING "Enable ARM NEON optimizations: on|off; on is default")
+  else()
+    set(PNG_ARM_NEON_POSSIBLE_VALUES check on off)
+    set(PNG_ARM_NEON "off"
+        CACHE STRING "Enable ARM NEON optimizations: check|on|off; off is default")
+  endif()
+  set_property(CACHE PNG_ARM_NEON
+               PROPERTY STRINGS ${PNG_ARM_NEON_POSSIBLE_VALUES})
+  list(FIND PNG_ARM_NEON_POSSIBLE_VALUES ${PNG_ARM_NEON} index)
+  if(index EQUAL -1)
+    message(FATAL_ERROR "PNG_ARM_NEON must be one of [${PNG_ARM_NEON_POSSIBLE_VALUES}]")
+  elseif(NOT PNG_ARM_NEON STREQUAL "off")
+    set(libpng_arm_sources
+        arm/arm_init.c
+        arm/filter_neon_intrinsics.c
+        arm/palette_neon_intrinsics.c)
+    if(NOT MSVC)
+      list(APPEND libpng_arm_sources arm/filter_neon.S)
+    endif()
+    if(PNG_ARM_NEON STREQUAL "on")
+      add_definitions(-DPNG_ARM_NEON_OPT=2)
+    elseif(PNG_ARM_NEON STREQUAL "check")
+      add_definitions(-DPNG_ARM_NEON_CHECK_SUPPORTED)
+    endif()
+  else()
+    add_definitions(-DPNG_ARM_NEON_OPT=0)
+  endif()
+endif()
+
+# Set definitions and sources for PowerPC.
+if(TARGET_ARCH MATCHES "^(powerpc|ppc64)")
+  set(PNG_POWERPC_VSX_POSSIBLE_VALUES on off)
+  set(PNG_POWERPC_VSX "on"
+      CACHE STRING "Enable POWERPC VSX optimizations: on|off; on is default")
+  set_property(CACHE PNG_POWERPC_VSX
+               PROPERTY STRINGS ${PNG_POWERPC_VSX_POSSIBLE_VALUES})
+  list(FIND PNG_POWERPC_VSX_POSSIBLE_VALUES ${PNG_POWERPC_VSX} index)
+  if(index EQUAL -1)
+    message(FATAL_ERROR "PNG_POWERPC_VSX must be one of [${PNG_POWERPC_VSX_POSSIBLE_VALUES}]")
+  elseif(NOT PNG_POWERPC_VSX STREQUAL "off")
+    set(libpng_powerpc_sources
+        powerpc/powerpc_init.c
+        powerpc/filter_vsx_intrinsics.c)
+    if(PNG_POWERPC_VSX STREQUAL "on")
+      add_definitions(-DPNG_POWERPC_VSX_OPT=2)
+    endif()
+  else()
+    add_definitions(-DPNG_POWERPC_VSX_OPT=0)
+  endif()
+endif()
+
+# Set definitions and sources for Intel.
+if(TARGET_ARCH MATCHES "^(i[3-6]86|x86|AMD64)")
+  set(PNG_INTEL_SSE_POSSIBLE_VALUES on off)
+  set(PNG_INTEL_SSE "on"
+      CACHE STRING "Enable INTEL_SSE optimizations: on|off; on is default")
+  set_property(CACHE PNG_INTEL_SSE
+               PROPERTY STRINGS ${PNG_INTEL_SSE_POSSIBLE_VALUES})
+  list(FIND PNG_INTEL_SSE_POSSIBLE_VALUES ${PNG_INTEL_SSE} index)
+  if(index EQUAL -1)
+    message(FATAL_ERROR "PNG_INTEL_SSE must be one of [${PNG_INTEL_SSE_POSSIBLE_VALUES}]")
+  elseif(NOT PNG_INTEL_SSE STREQUAL "off")
+    set(libpng_intel_sources
+        intel/intel_init.c
+        intel/filter_sse2_intrinsics.c)
+    if(PNG_INTEL_SSE STREQUAL "on")
+      add_definitions(-DPNG_INTEL_SSE_OPT=1)
+    endif()
+  else()
+    add_definitions(-DPNG_INTEL_SSE_OPT=0)
+  endif()
+endif()
+
+# Set definitions and sources for MIPS.
+if(TARGET_ARCH MATCHES "^(mipsel|mips64el)")
+  set(PNG_MIPS_MSA_POSSIBLE_VALUES on off)
+  set(PNG_MIPS_MSA "on"
+      CACHE STRING "Enable MIPS_MSA optimizations: on|off; on is default")
+  set_property(CACHE PNG_MIPS_MSA
+               PROPERTY STRINGS ${PNG_MIPS_MSA_POSSIBLE_VALUES})
+  list(FIND PNG_MIPS_MSA_POSSIBLE_VALUES ${PNG_MIPS_MSA} index_msa)
+  if(index_msa EQUAL -1)
+    message(FATAL_ERROR "PNG_MIPS_MSA must be one of [${PNG_MIPS_MSA_POSSIBLE_VALUES}]")
+  endif()
+
+  set(PNG_MIPS_MMI_POSSIBLE_VALUES on off)
+  set(PNG_MIPS_MMI "on"
+      CACHE STRING "Enable MIPS_MMI optimizations: on|off; on is default")
+  set_property(CACHE PNG_MIPS_MMI
+               PROPERTY STRINGS ${PNG_MIPS_MMI_POSSIBLE_VALUES})
+  list(FIND PNG_MIPS_MMI_POSSIBLE_VALUES ${PNG_MIPS_MMI} index_mmi)
+  if(index_mmi EQUAL -1)
+    message(FATAL_ERROR "PNG_MIPS_MMI must be one of [${PNG_MIPS_MMI_POSSIBLE_VALUES}]")
+  endif()
+
+  if(PNG_MIPS_MSA STREQUAL "on" AND PNG_MIPS_MMI STREQUAL "on")
+    set(libpng_mips_sources
+        mips/mips_init.c
+        mips/filter_msa_intrinsics.c
+        mips/filter_mmi_inline_assembly.c)
+    add_definitions(-DPNG_MIPS_MSA_OPT=2)
+    add_definitions(-DPNG_MIPS_MMI_OPT=1)
+  elseif(PNG_MIPS_MSA STREQUAL "on")
+    set(libpng_mips_sources
+        mips/mips_init.c
+        mips/filter_msa_intrinsics.c)
+    add_definitions(-DPNG_MIPS_MSA_OPT=2)
+    add_definitions(-DPNG_MIPS_MMI_OPT=0)
+  elseif(PNG_MIPS_MMI STREQUAL "on")
+    set(libpng_mips_sources
+        mips/mips_init.c
+        mips/filter_mmi_inline_assembly.c)
+    add_definitions(-DPNG_MIPS_MSA_OPT=0)
+    add_definitions(-DPNG_MIPS_MMI_OPT=1)
+    else()
+    add_definitions(-DPNG_MIPS_MSA_OPT=0)
+    add_definitions(-DPNG_MIPS_MMI_OPT=0)
+    endif()
+endif()
+
+# Set definitions and sources for LoongArch.
+if(TARGET_ARCH MATCHES "^(loongarch)")
+  include(CheckCCompilerFlag)
+  set(PNG_LOONGARCH_LSX_POSSIBLE_VALUES on off)
+  set(PNG_LOONGARCH_LSX "on"
+      CACHE STRING "Enable LOONGARCH_LSX optimizations: on|off; on is default")
+  set_property(CACHE PNG_LOONGARCH_LSX
+               PROPERTY STRINGS ${PNG_LOONGARCH_LSX_POSSIBLE_VALUES})
+  list(FIND PNG_LOONGARCH_LSX_POSSIBLE_VALUES ${PNG_LOONGARCH_LSX} index)
+  if(index EQUAL -1)
+    message(FATAL_ERROR "PNG_LOONGARCH_LSX must be one of [${PNG_LOONGARCH_LSX_POSSIBLE_VALUES}]")
+  elseif(NOT PNG_LOONGARCH_LSX STREQUAL "off")
+    CHECK_C_COMPILER_FLAG("-mlsx" COMPILER_SUPPORTS_LSX)
+    if(COMPILER_SUPPORTS_LSX)
+      set(libpng_loongarch_sources
+          loongarch/loongarch_lsx_init.c
+          loongarch/filter_lsx_intrinsics.c)
+      set_source_files_properties(${libpng_loongarch_sources}
+                                  PROPERTIES
+                                  COMPILE_FLAGS "-mlsx")
+      add_definitions(-DPNG_LOONGARCH_LSX_OPT=1)
+    else()
+      message(FATAL_ERROR "Compiler does not support -mlsx option")
+    endif()
+  else()
+    add_definitions(-DPNG_LOONGARCH_LSX_OPT=0)
+  endif()
+endif()
+
+else(PNG_HARDWARE_OPTIMIZATIONS)
+
+# Set definitions and sources for ARM.
+if(TARGET_ARCH MATCHES "^(ARM|arm|aarch)")
+  add_definitions(-DPNG_ARM_NEON_OPT=0)
+endif()
+
+# Set definitions and sources for PowerPC.
+if(TARGET_ARCH MATCHES "^(powerpc|ppc64)")
+  add_definitions(-DPNG_POWERPC_VSX_OPT=0)
+endif()
+
+# Set definitions and sources for Intel.
+if(TARGET_ARCH MATCHES "^(i[3-6]86|x86|AMD64)")
+  add_definitions(-DPNG_INTEL_SSE_OPT=0)
+endif()
+
+# Set definitions and sources for MIPS.
+if(TARGET_ARCH MATCHES "^(mipsel|mips64el)")
+  add_definitions(-DPNG_MIPS_MSA_OPT=0)
+endif()
+
+# Set definitions and sources for LoongArch.
+if(TARGET_ARCH MATCHES "^(loongarch)")
+  add_definitions(-DPNG_LOONGARCH_LSX_OPT=0)
+endif()
+
+endif(PNG_HARDWARE_OPTIMIZATIONS)
+
+option(ld-version-script "Enable linker version script" ON)
+if(ld-version-script AND NOT ANDROID AND NOT APPLE)
+  # Check if LD supports linker scripts.
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/conftest.map" "
+VERS_1 { global: sym1; local: *; };
+VERS_2 { global: sym2; main; } VERS_1;
+")
+  set(_SAVED_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
+  if(NOT CMAKE_HOST_SOLARIS)
+    # Avoid using CMAKE_SHARED_LIBRARY_C_FLAGS in version script checks on
+    # Solaris, because of an incompatibility with the Solaris link editor.
+    list(APPEND CMAKE_REQUIRED_FLAGS ${CMAKE_SHARED_LIBRARY_C_FLAGS})
+  endif()
+  list(APPEND CMAKE_REQUIRED_FLAGS "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/conftest.map'")
+  check_c_source_compiles("
+void sym1(void) {}
+void sym2(void) {}
+int main(void) { return 0; }
+" HAVE_LD_VERSION_SCRIPT)
+  if(NOT HAVE_LD_VERSION_SCRIPT)
+    set(CMAKE_REQUIRED_FLAGS ${_SAVED_CMAKE_REQUIRED_FLAGS})
+    if(NOT CMAKE_HOST_SOLARIS)
+      # Again, avoid using CMAKE_SHARED_LIBRARY_C_FLAGS in version script
+      # checks on Solaris.
+      list(APPEND CMAKE_REQUIRED_FLAGS ${CMAKE_SHARED_LIBRARY_C_FLAGS})
+    endif()
+    list(APPEND CMAKE_REQUIRED_FLAGS "-Wl,-M -Wl,${CMAKE_CURRENT_BINARY_DIR}/conftest.map")
+    check_c_source_compiles("
+void sym1(void) {}
+void sym2(void) {}
+int main(void) { return 0; }
+" HAVE_SOLARIS_LD_VERSION_SCRIPT)
+  endif()
+  set(CMAKE_REQUIRED_FLAGS ${_SAVED_CMAKE_REQUIRED_FLAGS})
+  file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/conftest.map")
+endif()
+
+# Find an AWK language processor.
+# Start with specific AWK implementations like gawk and nawk, which are
+# known to work with our scripts, then fall back to the system awk.
+find_program(AWK NAMES gawk nawk awk)
+if(AWK)
+  message(STATUS "Found AWK program: ${AWK}")
+else()
+  message(STATUS "Could not find an AWK-compatible program")
+endif()
+
+include_directories(${CMAKE_CURRENT_BINARY_DIR})
+
+if(NOT AWK OR ANDROID OR IOS)
+  # No awk available to generate sources; use pre-built pnglibconf.h
+  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt
+                 ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h)
+  add_custom_target(png_genfiles)
+else()
+  # Copy the awk scripts, converting their line endings to Unix (LF)
+  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/checksym.awk
+                 ${CMAKE_CURRENT_BINARY_DIR}/scripts/checksym.awk
+                 @ONLY
+                 NEWLINE_STYLE LF)
+  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/options.awk
+                 ${CMAKE_CURRENT_BINARY_DIR}/scripts/options.awk
+                 @ONLY
+                 NEWLINE_STYLE LF)
+  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/dfn.awk
+                 ${CMAKE_CURRENT_BINARY_DIR}/scripts/dfn.awk
+                 @ONLY
+                 NEWLINE_STYLE LF)
+
+  # Generate .chk from .out with awk:
+  # generate_chk(INPUT inputfile OUTPUT outputfile [DEPENDS dep1 [dep2...]])
+  function(generate_chk)
+    set(options)
+    set(oneValueArgs INPUT OUTPUT)
+    set(multiValueArgs DEPENDS)
+    cmake_parse_arguments(_GC "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+    if(NOT _GC_INPUT)
+      message(FATAL_ERROR "generate_chk: Missing INPUT argument")
+    endif()
+    if(NOT _GC_OUTPUT)
+      message(FATAL_ERROR "generate_chk: Missing OUTPUT argument")
+    endif()
+
+    add_custom_command(OUTPUT "${_GC_OUTPUT}"
+                       COMMAND "${CMAKE_COMMAND}"
+                               "-DINPUT=${_GC_INPUT}"
+                               "-DOUTPUT=${_GC_OUTPUT}"
+                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genchk.cmake"
+                       DEPENDS "${_GC_INPUT}" ${_GC_DEPENDS}
+                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+  endfunction()
+
+  # Generate .out from .c with awk
+  # generate_out(INPUT inputfile OUTPUT outputfile [DEPENDS dep1 [dep2...]])
+  function(generate_out)
+    set(options)
+    set(oneValueArgs INPUT OUTPUT)
+    set(multiValueArgs DEPENDS)
+    cmake_parse_arguments(_GO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+    if(NOT _GO_INPUT)
+      message(FATAL_ERROR "generate_out: Missing INPUT argument")
+    endif()
+    if(NOT _GO_OUTPUT)
+      message(FATAL_ERROR "generate_out: Missing OUTPUT argument")
+    endif()
+
+    add_custom_command(OUTPUT "${_GO_OUTPUT}"
+                       COMMAND "${CMAKE_COMMAND}"
+                               "-DINPUT=${_GO_INPUT}"
+                               "-DOUTPUT=${_GO_OUTPUT}"
+                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genout.cmake"
+                       DEPENDS "${_GO_INPUT}" ${_GO_DEPENDS}
+                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+  endfunction()
+
+  # Generate specific source file with awk
+  # generate_source(OUTPUT outputfile [DEPENDS dep1 [dep2...]])
+  function(generate_source)
+    set(options)
+    set(oneValueArgs OUTPUT)
+    set(multiValueArgs DEPENDS)
+    cmake_parse_arguments(_GSO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+    if(NOT _GSO_OUTPUT)
+      message(FATAL_ERROR "generate_source: Missing OUTPUT argument")
+    endif()
+
+    add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${_GSO_OUTPUT}"
+                       COMMAND "${CMAKE_COMMAND}"
+                               "-DOUTPUT=${_GSO_OUTPUT}"
+                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/gensrc.cmake"
+                       DEPENDS ${_GSO_DEPENDS}
+                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+  endfunction()
+
+  # Copy file
+  # generate_copy(INPUT inputfile OUTPUT outputfile [DEPENDS dep1 [dep2...]])
+  function(generate_copy)
+    set(options)
+    set(oneValueArgs INPUT OUTPUT)
+    set(multiValueArgs DEPENDS)
+    cmake_parse_arguments(_GCO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+    if(NOT _GCO_INPUT)
+      message(FATAL_ERROR "generate_copy: Missing INPUT argument")
+    endif()
+    if(NOT _GCO_OUTPUT)
+      message(FATAL_ERROR "generate_copy: Missing OUTPUT argument")
+    endif()
+
+    add_custom_command(OUTPUT "${_GCO_OUTPUT}"
+                       COMMAND "${CMAKE_COMMAND}"
+                               -E remove "${_GCO_OUTPUT}"
+                       COMMAND "${CMAKE_COMMAND}"
+                               -E copy "${_GCO_INPUT}" "${_GCO_OUTPUT}"
+                       DEPENDS "${source}" ${_GCO_DEPENDS})
+  endfunction()
+
+  # Generate scripts/pnglibconf.h
+  generate_source(OUTPUT "scripts/pnglibconf.c"
+                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
+                          "${CMAKE_CURRENT_BINARY_DIR}/scripts/options.awk"
+                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")
+  add_custom_target(png_scripts_pnglibconf_c
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/pnglibconf.c")
+
+  # Generate pnglibconf.c
+  generate_source(OUTPUT "pnglibconf.c"
+                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
+                          "${CMAKE_CURRENT_BINARY_DIR}/scripts/options.awk"
+                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")
+  add_custom_target(pnglibconf_c
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c")
+
+  if(PNG_PREFIX)
+    set(PNGLIBCONF_H_EXTRA_DEPENDS
+        "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
+        "${CMAKE_CURRENT_SOURCE_DIR}/scripts/macro.lst")
+    set(PNGPREFIX_H_EXTRA_DEPENDS
+        "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out")
+  endif()
+
+  generate_out(INPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
+               DEPENDS pnglibconf_c)
+  add_custom_target(pnglibconf_out
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out")
+
+  # Generate pnglibconf.h
+  generate_source(OUTPUT "pnglibconf.h"
+                  DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out" pnglibconf_out
+                          ${PNGLIBCONF_H_EXTRA_DEPENDS})
+  add_custom_target(pnglibconf_h
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/intprefix.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out"
+               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h" pnglibconf_h)
+  add_custom_target(png_scripts_intprefix_out
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out")
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/prefix.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
+               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
+                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out" pnglibconf_out)
+  add_custom_target(png_scripts_prefix_out
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out")
+
+  # Generate pngprefix.h
+  generate_source(OUTPUT "pngprefix.h"
+                  DEPENDS ${PNGPREFIX_H_EXTRA_DEPENDS})
+  add_custom_target(pngprefix_h
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h")
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/sym.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
+               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h" pnglibconf_h)
+  add_custom_target(png_scripts_sym_out
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out")
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
+               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt")
+  add_custom_target(png_scripts_symbols_out
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out")
+
+  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/vers.c"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
+               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
+                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h" pnglibconf_h)
+  add_custom_target(png_scripts_vers_out
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out")
+
+  generate_chk(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
+               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
+               DEPENDS png_scripts_symbols_out
+                       "${CMAKE_CURRENT_BINARY_DIR}/scripts/checksym.awk"
+                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.def")
+
+  add_custom_target(png_scripts_symbols_chk
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk")
+
+  generate_copy(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
+                OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym"
+                DEPENDS png_scripts_sym_out)
+  generate_copy(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
+                OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers"
+                DEPENDS png_scripts_vers_out)
+
+  add_custom_target(png_genvers
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers")
+  add_custom_target(png_gensym
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym")
+
+  add_custom_target(png_genprebuilt
+                    COMMAND "${CMAKE_COMMAND}"
+                            "-DOUTPUT=scripts/pnglibconf.h.prebuilt"
+                            -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/gensrc.cmake"
+                    WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+
+  # A single target handles generation of all generated files.
+  add_custom_target(png_genfiles
+                    DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym" png_gensym
+                            "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers" png_genvers
+                            "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c" pnglibconf_c
+                            "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h" pnglibconf_h
+                            "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out" pnglibconf_out
+                            "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h" pngprefix_h
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out" png_scripts_intprefix_out
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/pnglibconf.c" png_scripts_pnglibconf_c
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out" png_scripts_prefix_out
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out" png_scripts_sym_out
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk" png_scripts_symbols_chk
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out" png_scripts_symbols_out
+                            "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out" png_scripts_vers_out)
+endif(NOT AWK OR ANDROID OR IOS)
+
+# List the source code files.
+set(libpng_public_hdrs
+    png.h
+    pngconf.h
+    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
+)
+set(libpng_private_hdrs
+    pngpriv.h
+    pngdebug.h
+    pnginfo.h
+    pngstruct.h
+)
+if(AWK AND NOT ANDROID AND NOT IOS)
+  list(APPEND libpng_private_hdrs "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h")
+endif()
+set(libpng_sources
+    ${libpng_public_hdrs}
+    ${libpng_private_hdrs}
+    png.c
+    pngerror.c
+    pngget.c
+    pngmem.c
+    pngpread.c
+    pngread.c
+    pngrio.c
+    pngrtran.c
+    pngrutil.c
+    pngset.c
+    pngtrans.c
+    pngwio.c
+    pngwrite.c
+    pngwtran.c
+    pngwutil.c
+    ${libpng_arm_sources}
+    ${libpng_intel_sources}
+    ${libpng_mips_sources}
+    ${libpng_powerpc_sources}
+    ${libpng_loongarch_sources}
+)
+set(pngtest_sources
+    pngtest.c
+)
+set(pngvalid_sources
+    contrib/libtests/pngvalid.c
+)
+set(pngstest_sources
+    contrib/libtests/pngstest.c
+)
+set(pngunknown_sources
+    contrib/libtests/pngunknown.c
+)
+set(pngimage_sources
+    contrib/libtests/pngimage.c
+)
+set(pngfix_sources
+    contrib/tools/pngfix.c
+)
+set(png_fix_itxt_sources
+    contrib/tools/png-fix-itxt.c
+)
+
+if(MSVC OR (WIN32 AND (CMAKE_C_COMPILER_ID MATCHES "Clang")))
+  add_definitions(-D_CRT_NONSTDC_NO_DEPRECATE)
+  add_definitions(-D_CRT_SECURE_NO_DEPRECATE)
+endif()
+
+if(PNG_DEBUG)
+  add_definitions(-DPNG_DEBUG)
+endif()
+
+# Now build our targets.
+
+# Initialize the list of libpng library targets.
+set(PNG_LIBRARY_TARGETS "")
+
+# Initialize the libpng library file names.
+if(UNIX
+   OR (WIN32 AND NOT CMAKE_SHARED_LIBRARY_PREFIX STREQUAL "")
+   OR (WIN32 AND NOT CMAKE_STATIC_LIBRARY_PREFIX STREQUAL ""))
+  # We are on a Unix or Unix-like toolchain like the GNU toolchain on Windows.
+  # Library file names are expected to have an implicit prefix such as "lib".
+  # Let CMake prepend and append its usual prefixes and suffixes by default.
+  set(PNG_SHARED_OUTPUT_NAME "png${PNGLIB_ABI_VERSION}")
+  set(PNG_STATIC_OUTPUT_NAME "png${PNGLIB_ABI_VERSION}")
+else()
+  # We are, most likely, on a Windows toolchain like MSVC, Clang on Windows,
+  # Borland/Embarcadero, etc. We need to specify the "libpng" name explicitly.
+  # We also need to use a custom suffix, in order to distinguish between the
+  # shared import library name and the static library name.
+  set(PNG_SHARED_OUTPUT_NAME "libpng${PNGLIB_ABI_VERSION}")
+  set(PNG_STATIC_OUTPUT_NAME "libpng${PNGLIB_ABI_VERSION}_static")
+endif()
+
+if(PNG_SHARED)
+  add_library(png_shared SHARED ${libpng_sources})
+  add_dependencies(png_shared png_genfiles)
+  list(APPEND PNG_LIBRARY_TARGETS png_shared)
+  set_target_properties(png_shared PROPERTIES
+                        OUTPUT_NAME "${PNG_SHARED_OUTPUT_NAME}"
+                        DEBUG_POSTFIX "${PNG_DEBUG_POSTFIX}"
+                        VERSION "${PNGLIB_SHARED_VERSION}"
+                        SOVERSION "${PNGLIB_ABI_VERSION}")
+  if(UNIX AND AWK)
+    if(HAVE_LD_VERSION_SCRIPT)
+      set_target_properties(png_shared PROPERTIES
+                            LINK_FLAGS "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
+    elseif(HAVE_SOLARIS_LD_VERSION_SCRIPT)
+      set_target_properties(png_shared PROPERTIES
+                            LINK_FLAGS "-Wl,-M -Wl,'${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
+    endif()
+  endif()
+  if(APPLE)
+    # Avoid CMake's implicit compile definition "png_shared_EXPORTS".
+    set_target_properties(png_shared PROPERTIES DEFINE_SYMBOL "")
+  elseif(WIN32)
+    # Use the explicit compile definition "PNG_BUILD_DLL" for Windows DLLs.
+    set_target_properties(png_shared PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
+  endif()
+  target_include_directories(png_shared
+                             PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>)
+  target_include_directories(png_shared SYSTEM
+                             INTERFACE $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>)
+  target_link_libraries(png_shared PUBLIC ZLIB::ZLIB ${M_LIBRARY})
+endif()
+
+if(PNG_STATIC)
+  add_library(png_static STATIC ${libpng_sources})
+  add_dependencies(png_static png_genfiles)
+  list(APPEND PNG_LIBRARY_TARGETS png_static)
+  set_target_properties(png_static PROPERTIES
+                        OUTPUT_NAME "${PNG_STATIC_OUTPUT_NAME}"
+                        DEBUG_POSTFIX "${PNG_DEBUG_POSTFIX}")
+  target_include_directories(png_static
+                             PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>)
+  target_include_directories(png_static SYSTEM
+                             INTERFACE $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>)
+  target_link_libraries(png_static PUBLIC ZLIB::ZLIB ${M_LIBRARY})
+endif()
+
+if(PNG_FRAMEWORK AND NOT APPLE)
+  message(AUTHOR_WARNING
+          "Setting PNG_FRAMEWORK to OFF, as it only applies to Apple systems")
+  set(PNG_FRAMEWORK OFF)
+endif()
+
+if(PNG_FRAMEWORK)
+  add_library(png_framework SHARED ${libpng_sources})
+  add_dependencies(png_framework png_genfiles)
+  list(APPEND PNG_LIBRARY_TARGETS png_framework)
+  set_target_properties(png_framework PROPERTIES
+                        FRAMEWORK TRUE
+                        FRAMEWORK_VERSION "${PNGLIB_VERSION}"
+                        MACOSX_FRAMEWORK_SHORT_VERSION_STRING "${PNGLIB_MAJOR}.${PNGLIB_MINOR}"
+                        MACOSX_FRAMEWORK_BUNDLE_VERSION "${PNGLIB_VERSION}"
+                        MACOSX_FRAMEWORK_IDENTIFIER "org.libpng.libpng"
+                        XCODE_ATTRIBUTE_INSTALL_PATH "@rpath"
+                        PUBLIC_HEADER "${libpng_public_hdrs}"
+                        OUTPUT_NAME "png"
+                        DEBUG_POSTFIX "${PNG_DEBUG_POSTFIX}")
+  # Avoid CMake's implicit compile definition "-Dpng_framework_EXPORTS".
+  set_target_properties(png_framework PROPERTIES DEFINE_SYMBOL "")
+  target_include_directories(png_framework
+                             PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>)
+  target_include_directories(png_framework SYSTEM
+                             INTERFACE $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>)
+  target_link_libraries(png_framework PUBLIC ZLIB::ZLIB ${M_LIBRARY})
+endif()
+
+if(NOT PNG_LIBRARY_TARGETS)
+  message(SEND_ERROR "No library variant selected to build. "
+                     "Please enable at least one of the following options: "
+                     "PNG_SHARED, PNG_STATIC, PNG_FRAMEWORK")
+endif()
+
+if(PNG_TESTS AND PNG_SHARED)
+  enable_testing()
+
+  function(png_add_test)
+    set(options)
+    set(oneValueArgs NAME COMMAND)
+    set(multiValueArgs OPTIONS FILES)
+    cmake_parse_arguments(_PAT "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
+    if(NOT _PAT_NAME)
+      message(FATAL_ERROR "png_add_test: Missing NAME argument")
+    endif()
+    if(NOT _PAT_COMMAND)
+      message(FATAL_ERROR "png_add_test: Missing COMMAND argument")
+    endif()
+
+    set(TEST_OPTIONS "${_PAT_OPTIONS}")
+    set(TEST_FILES "${_PAT_FILES}")
+
+    configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/test.cmake.in"
+                   "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake"
+                   @ONLY)
+    add_test(NAME "${_PAT_NAME}"
+             COMMAND "${CMAKE_COMMAND}"
+                     "-DLIBPNG=$<TARGET_FILE:png_shared>"
+                     "-DTEST_COMMAND=$<TARGET_FILE:${_PAT_COMMAND}>"
+                     -P "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake")
+  endfunction()
+
+  # Find test PNG files by globbing, but sort lists to ensure
+  # consistency between different filesystems.
+  file(GLOB PNGSUITE_PNGS "${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/*.png")
+  list(SORT PNGSUITE_PNGS)
+  file(GLOB TEST_PNGS "${CMAKE_CURRENT_SOURCE_DIR}/contrib/testpngs/*.png")
+  list(SORT TEST_PNGS)
+
+  set(PNGTEST_PNG "${CMAKE_CURRENT_SOURCE_DIR}/pngtest.png")
+
+  add_executable(pngtest ${pngtest_sources})
+  target_link_libraries(pngtest PRIVATE png_shared)
+
+  png_add_test(NAME pngtest
+               COMMAND pngtest
+               FILES "${PNGTEST_PNG}")
+
+  add_executable(pngvalid ${pngvalid_sources})
+  target_link_libraries(pngvalid PRIVATE png_shared)
+
+  png_add_test(NAME pngvalid-gamma-16-to-8
+               COMMAND pngvalid
+               OPTIONS --gamma-16-to-8)
+  png_add_test(NAME pngvalid-gamma-alpha-mode
+               COMMAND pngvalid
+               OPTIONS --gamma-alpha-mode)
+  png_add_test(NAME pngvalid-gamma-background
+               COMMAND pngvalid
+               OPTIONS --gamma-background)
+  png_add_test(NAME pngvalid-gamma-expand16-alpha-mode
+               COMMAND pngvalid
+               OPTIONS --gamma-alpha-mode --expand16)
+  png_add_test(NAME pngvalid-gamma-expand16-background
+               COMMAND pngvalid
+               OPTIONS --gamma-background --expand16)
+  png_add_test(NAME pngvalid-gamma-expand16-transform
+               COMMAND pngvalid
+               OPTIONS --gamma-transform --expand16)
+  png_add_test(NAME pngvalid-gamma-sbit
+               COMMAND pngvalid
+               OPTIONS --gamma-sbit)
+  png_add_test(NAME pngvalid-gamma-threshold
+               COMMAND pngvalid
+               OPTIONS --gamma-threshold)
+  png_add_test(NAME pngvalid-gamma-transform
+               COMMAND pngvalid
+               OPTIONS --gamma-transform)
+  png_add_test(NAME pngvalid-progressive-interlace-standard
+               COMMAND pngvalid
+               OPTIONS --standard --progressive-read --interlace)
+  png_add_test(NAME pngvalid-progressive-size
+               COMMAND pngvalid
+               OPTIONS --size --progressive-read)
+  png_add_test(NAME pngvalid-progressive-standard
+               COMMAND pngvalid
+               OPTIONS --standard --progressive-read)
+  png_add_test(NAME pngvalid-standard
+               COMMAND pngvalid
+               OPTIONS --standard)
+  png_add_test(NAME pngvalid-transform
+               COMMAND pngvalid
+               OPTIONS --transform)
+
+  add_executable(pngstest ${pngstest_sources})
+  target_link_libraries(pngstest PRIVATE png_shared)
+
+  foreach(gamma_type 1.8 linear none sRGB)
+    foreach(alpha_type none alpha)
+      set(PNGSTEST_FILES)
+      foreach(test_png ${TEST_PNGS})
+        string(REGEX MATCH "-linear[-.]" TEST_PNG_LINEAR "${test_png}")
+        string(REGEX MATCH "-sRGB[-.]" TEST_PNG_SRGB "${test_png}")
+        string(REGEX MATCH "-1.8[-.]" TEST_PNG_G18 "${test_png}")
+        string(REGEX MATCH "-alpha-" TEST_PNG_ALPHA "${test_png}")
+
+        set(TEST_PNG_VALID TRUE)
+
+        if(TEST_PNG_ALPHA)
+          if(NOT alpha_type STREQUAL "alpha")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        else()
+          if(alpha_type STREQUAL "alpha")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        endif()
+
+        if(TEST_PNG_LINEAR)
+          if(NOT gamma_type STREQUAL "linear")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        elseif(TEST_PNG_SRGB)
+          if(NOT gamma_type STREQUAL "sRGB")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        elseif(TEST_PNG_G18)
+          if(NOT gamma_type STREQUAL "1.8")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        else()
+          if(NOT gamma_type STREQUAL "none")
+            set(TEST_PNG_VALID FALSE)
+          endif()
+        endif()
+
+        if(TEST_PNG_VALID)
+          list(APPEND PNGSTEST_FILES "${test_png}")
+        endif()
+      endforeach()
+      # Should already be sorted, but sort anyway to be certain.
+      list(SORT PNGSTEST_FILES)
+      png_add_test(NAME pngstest-${gamma_type}-${alpha_type}
+                   COMMAND pngstest
+                   OPTIONS --tmpfile "${gamma_type}-${alpha_type}-" --log
+                   FILES ${PNGSTEST_FILES})
+    endforeach()
+  endforeach()
+
+  add_executable(pngunknown ${pngunknown_sources})
+  target_link_libraries(pngunknown PRIVATE png_shared)
+
+  png_add_test(NAME pngunknown-discard
+               COMMAND pngunknown
+               OPTIONS --strict default=discard
+               FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-IDAT
+               COMMAND pngunknown
+               OPTIONS --strict default=discard IDAT=save
+               FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-if-safe
+               COMMAND pngunknown
+               OPTIONS --strict default=if-safe
+               FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-sAPI
+               COMMAND pngunknown
+               OPTIONS --strict bKGD=save cHRM=save gAMA=save all=discard iCCP=save sBIT=save sRGB=save
+               FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-save
+               COMMAND pngunknown
+               OPTIONS --strict default=save
+               FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-sTER
+               COMMAND pngunknown
+               OPTIONS --strict sTER=if-safe
+               FILES "${PNGTEST_PNG}")
+  png_add_test(NAME pngunknown-vpAg
+               COMMAND pngunknown
+               OPTIONS --strict vpAg=if-safe
+               FILES "${PNGTEST_PNG}")
+
+  add_executable(pngimage ${pngimage_sources})
+  target_link_libraries(pngimage PRIVATE png_shared)
+
+  png_add_test(NAME pngimage-quick
+               COMMAND pngimage
+               OPTIONS --list-combos --log
+               FILES ${PNGSUITE_PNGS})
+  png_add_test(NAME pngimage-full
+               COMMAND pngimage
+               OPTIONS --exhaustive --list-combos --log
+               FILES ${PNGSUITE_PNGS})
+endif()
+
+if(PNG_SHARED AND PNG_TOOLS)
+  add_executable(pngfix ${pngfix_sources})
+  target_link_libraries(pngfix PRIVATE png_shared)
+  set(PNG_BIN_TARGETS pngfix)
+
+  add_executable(png-fix-itxt ${png_fix_itxt_sources})
+  target_link_libraries(png-fix-itxt PRIVATE ZLIB::ZLIB ${M_LIBRARY})
+  list(APPEND PNG_BIN_TARGETS png-fix-itxt)
+endif()
+
+# Create a symlink from src to dest (if possible), or, alternatively,
+# copy src to dest if different.
+function(create_symlink DEST_FILE)
+  cmake_parse_arguments(_SYM "" "FILE;TARGET" "" ${ARGN})
+  if(NOT _SYM_FILE AND NOT _SYM_TARGET)
+    message(FATAL_ERROR "create_symlink: Missing FILE or TARGET argument")
+  endif()
+  if(_SYM_FILE AND _SYM_TARGET)
+    message(FATAL_ERROR "create_symlink: "
+                        "The arguments FILE (${_SYM_FILE}) and TARGET (${_SYM_TARGET}) "
+                        "are mutually-exclusive")
+  endif()
+
+  if(_SYM_FILE)
+    # If we don't need to symlink something that's coming from a build target,
+    # we can go ahead and symlink/copy at configure time.
+    if(CMAKE_HOST_WIN32 AND NOT CYGWIN)
+      execute_process(COMMAND "${CMAKE_COMMAND}"
+                              -E copy_if_different
+                              ${_SYM_FILE} ${DEST_FILE}
+                      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+    else()
+      execute_process(COMMAND "${CMAKE_COMMAND}"
+                              -E create_symlink
+                              ${_SYM_FILE} ${DEST_FILE}
+                      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+    endif()
+  endif()
+
+  if(_SYM_TARGET)
+    # We need to use generator expressions, which can be a bit tricky.
+    # For simplicity, make the symlink a POST_BUILD step, and use the TARGET
+    # signature of add_custom_command.
+    if(CMAKE_HOST_WIN32 AND NOT CYGWIN)
+      add_custom_command(TARGET ${_SYM_TARGET}
+                         POST_BUILD
+                         COMMAND "${CMAKE_COMMAND}"
+                                 -E copy_if_different
+                                 $<TARGET_LINKER_FILE_DIR:${_SYM_TARGET}>/$<TARGET_LINKER_FILE_NAME:${_SYM_TARGET}>
+                                 $<TARGET_LINKER_FILE_DIR:${_SYM_TARGET}>/${DEST_FILE})
+    else()
+      add_custom_command(TARGET ${_SYM_TARGET}
+                         POST_BUILD
+                         COMMAND "${CMAKE_COMMAND}"
+                                 -E create_symlink
+                                 $<TARGET_LINKER_FILE_NAME:${_SYM_TARGET}>
+                                 $<TARGET_LINKER_FILE_DIR:${_SYM_TARGET}>/${DEST_FILE})
+    endif()
+  endif()
+endfunction()
+
+# Create source generation scripts.
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/genchk.cmake.in
+               ${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genchk.cmake
+               @ONLY)
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/genout.cmake.in
+               ${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/genout.cmake
+               @ONLY)
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/cmake/gensrc.cmake.in
+               ${CMAKE_CURRENT_BINARY_DIR}/scripts/cmake/gensrc.cmake
+               @ONLY)
+
+# libpng is a library so default to 'lib'
+if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
+  set(CMAKE_INSTALL_LIBDIR lib)
+endif()
+
+# Create pkgconfig files.
+# We use the same files like ./configure, so we have to set its vars.
+# Only do this on Windows for Cygwin - the files don't make much sense
+# outside of a UNIX look-alike.
+if(NOT WIN32 OR CYGWIN OR MINGW)
+  set(prefix      ${CMAKE_INSTALL_PREFIX})
+  set(exec_prefix ${CMAKE_INSTALL_PREFIX})
+  set(libdir      ${CMAKE_INSTALL_FULL_LIBDIR})
+  set(includedir  ${CMAKE_INSTALL_FULL_INCLUDEDIR})
+  set(LIBS        "-lz -lm")
+  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in
+                 ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}.pc
+                 @ONLY)
+  create_symlink(libpng.pc FILE libpng${PNGLIB_ABI_VERSION}.pc)
+  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in
+                 ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}-config
+                 @ONLY)
+  create_symlink(libpng-config FILE libpng${PNGLIB_ABI_VERSION}-config)
+endif()
+
+# Install.
+if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL)
+  install(TARGETS ${PNG_LIBRARY_TARGETS}
+          EXPORT libpng
+          RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+          LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+          ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+          FRAMEWORK DESTINATION ${CMAKE_INSTALL_LIBDIR})
+
+  if(PNG_SHARED)
+    # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin
+    if(NOT WIN32 OR CYGWIN OR MINGW)
+      create_symlink(libpng${CMAKE_SHARED_LIBRARY_SUFFIX} TARGET png_shared)
+      install(FILES $<TARGET_LINKER_FILE_DIR:png_shared>/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
+              DESTINATION ${CMAKE_INSTALL_LIBDIR})
+    endif()
+  endif()
+
+  if(PNG_STATIC)
+    if(NOT WIN32 OR CYGWIN OR MINGW)
+      create_symlink(libpng${CMAKE_STATIC_LIBRARY_SUFFIX} TARGET png_static)
+      install(FILES $<TARGET_LINKER_FILE_DIR:png_static>/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
+              DESTINATION ${CMAKE_INSTALL_LIBDIR})
+    endif()
+  endif()
+endif()
+
+if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL)
+  install(FILES ${libpng_public_hdrs}
+          DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+  install(FILES ${libpng_public_hdrs}
+          DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION})
+endif()
+if(NOT SKIP_INSTALL_EXECUTABLES AND NOT SKIP_INSTALL_ALL)
+  if(NOT WIN32 OR CYGWIN OR MINGW)
+    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config
+            DESTINATION ${CMAKE_INSTALL_BINDIR})
+    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}-config
+            DESTINATION ${CMAKE_INSTALL_BINDIR})
+  endif()
+endif()
+
+if(NOT SKIP_INSTALL_PROGRAMS AND NOT SKIP_INSTALL_ALL)
+  install(TARGETS ${PNG_BIN_TARGETS}
+          RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL)
+  # Install the man pages.
+  install(FILES libpng.3 libpngpf.3
+          DESTINATION ${CMAKE_INSTALL_MANDIR}/man3)
+  install(FILES png.5
+          DESTINATION ${CMAKE_INSTALL_MANDIR}/man5)
+  # Install the pkg-config files.
+  if(NOT CMAKE_HOST_WIN32 OR CYGWIN OR MINGW)
+    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc
+            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config
+            DESTINATION ${CMAKE_INSTALL_BINDIR})
+    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}.pc
+            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng${PNGLIB_ABI_VERSION}-config
+            DESTINATION ${CMAKE_INSTALL_BINDIR})
+  endif()
+endif()
+
+# Create an export file that CMake users can include() to import our targets.
+if(NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL)
+  install(EXPORT libpng
+          DESTINATION ${CMAKE_INSTALL_LIBDIR}/libpng
+          FILE libpng${PNGLIB_ABI_VERSION}.cmake)
+endif()
+
+# TODO: Create MSVC import lib for MinGW-compiled shared lib.
+# pexports libpng.dll > libpng.def
+# lib /def:libpng.def /machine:x86
Index: /trunk/src/libs/libpng-1.6.45/INSTALL
===================================================================
--- /trunk/src/libs/libpng-1.6.45/INSTALL	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/INSTALL	(revision 107811)
@@ -0,0 +1,464 @@
+
+    Installing libpng
+
+Contents
+
+       I. Simple installation
+      II. Rebuilding the configure scripts
+     III. Using scripts/makefile*
+      IV. Using cmake
+       V. Directory structure
+      VI. Building with project files
+     VII. Building with makefiles
+    VIII. Configuring libpng for 16-bit platforms
+      IX. Configuring for DOS
+       X. Configuring for Medium Model
+      XI. Prepending a prefix to exported symbols
+     XII. Configuring for compiler xxx:
+    XIII. Removing unwanted object code
+     XIV. Enabling or disabling hardware optimizations
+      XV. Changes to the build and configuration of libpng in libpng-1.5.x
+     XVI. Setjmp/longjmp issues
+    XVII. Common linking failures
+   XVIII. Other sources of information about libpng
+
+I. Simple installation
+
+On Unix/Linux and similar systems, you can simply type
+
+    ./configure [--prefix=/path]
+    make check
+    make install
+
+and ignore the rest of this document.  "/path" is the path to the directory
+where you want to install the libpng "lib", "include", and "bin"
+subdirectories.
+
+If you downloaded a GIT clone, you will need to run ./autogen.sh before
+running ./configure, to create "configure" and "Makefile.in" which are
+not included in the GIT repository.
+
+Note that "configure" is only included in the "*.tar" distributions and not
+in the "*.zip" or "*.7z" distributions. If you downloaded one of those
+distributions, see "Building with project files" or "Building with makefiles",
+below.
+
+II. Rebuilding the configure scripts
+
+If configure does not work on your system, or if you have a need to
+change configure.ac or Makefile.am, and you have a reasonably
+up-to-date set of tools, running ./autogen.sh in a git clone before
+running ./configure may fix the problem.  To be really sure that you
+aren't using any of the included pre-built scripts, especially if you
+are building from a tar distribution instead of a git distribution,
+do this:
+
+    ./configure --enable-maintainer-mode
+    make maintainer-clean
+    ./autogen.sh --maintainer --clean
+    ./autogen.sh --maintainer
+    ./configure [--prefix=/path] [other options]
+    make
+    make install
+    make check
+
+III. Using scripts/makefile*
+
+Instead, you can use one of the custom-built makefiles in the
+"scripts" directory
+
+    cp scripts/pnglibconf.h.prebuilt pnglibconf.h
+    cp scripts/makefile.system makefile
+    make test
+    make install
+
+The files that are presently available in the scripts directory
+are listed and described in scripts/README.txt.
+
+Or you can use one of the "projects" in the "projects" directory.
+
+Before installing libpng, you must first install zlib, if it
+is not already on your system.  zlib can usually be found
+wherever you got libpng; otherwise go to https://zlib.net/.  You can
+place zlib in the same directory as libpng or in another directory.
+
+If your system already has a preinstalled zlib you will still need
+to have access to the zlib.h and zconf.h include files that
+correspond to the version of zlib that's installed.
+
+If you wish to test with a particular zlib that is not first in the
+standard library search path, put ZLIBLIB, ZLIBINC, CPPFLAGS, LDFLAGS,
+and LD_LIBRARY_PATH in your environment before running "make test"
+or "make distcheck":
+
+    ZLIBLIB=/path/to/lib export ZLIBLIB
+    ZLIBINC=/path/to/include export ZLIBINC
+    CPPFLAGS="-I$ZLIBINC" export CPPFLAGS
+    LDFLAGS="-L$ZLIBLIB" export LDFLAGS
+    LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
+
+If you are using one of the makefile scripts, put ZLIBLIB and ZLIBINC
+in your environment and type
+
+    make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test
+
+IV. Using cmake
+
+If you want to use "cmake" (see www.cmake.org), type
+
+    cmake . -DCMAKE_INSTALL_PREFIX=/path
+    make
+    make install
+
+As when using the simple configure method described above, "/path" points to
+the installation directory where you want to put the libpng "lib", "include",
+and "bin" subdirectories.
+
+V. Directory structure
+
+You can rename the directories that you downloaded (they
+might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.8"
+or "zlib128") so that you have directories called "zlib" and "libpng".
+
+Your directory structure should look like this:
+
+    .. (the parent directory)
+      libpng (this directory)
+          INSTALL (this file)
+          README
+          *.h, *.c  => libpng source files
+          CMakeLists.txt    =>  "cmake" script
+          ci
+             ci_*.sh
+          configuration files:
+             configure.ac, configure, Makefile.am, Makefile.in,
+             autogen.sh, config.guess, ltmain.sh, missing, libpng.pc.in,
+             libpng-config.in, aclocal.m4, config.h.in, config.sub,
+             depcomp, install-sh, mkinstalldirs, test-pngtest.sh, etc.
+          contrib
+             arm-neon, conftest, examples, gregbook, libtests, pngminim,
+             pngminus, pngsuite, tools, visupng
+          projects
+             owatcom, visualc71, vstudio
+          scripts
+             makefile.*
+             *.def (module definition files)
+             etc.
+          pngtest.png
+          etc.
+      zlib
+          README, *.h, *.c, contrib, etc.
+
+If the line endings in the files look funny, you may wish to get the other
+distribution of libpng.  It is available in both tar.gz (UNIX style line
+endings) and zip (DOS style line endings) formats.
+
+VI. Building with project files
+
+If you are building libpng with Microsoft Visual Studio, you can enter
+the directory projects\visualc71 or projects\vstudio and follow the
+instructions in README.txt.
+
+Otherwise, enter the zlib directory and follow the instructions in
+zlib/README, then come back here and run "configure" or choose the
+appropriate makefile in the scripts directory.
+
+VII. Building with makefiles
+
+Copy the file (or files) that you need from the
+scripts directory into this directory, for example
+
+UNIX example:
+
+    cp scripts/makefile.std Makefile
+    make
+
+Windows example:
+
+    nmake -f scripts\makefile.vcwin32
+
+Read the makefile to see if you need to change any source or
+target directories to match your preferences.
+
+Then read pnglibconf.dfa to see if you want to make any configuration
+changes.
+
+Then just run "make" which will create the libpng library in
+this directory and "make test" which will run a quick test that reads
+the "pngtest.png" file and writes a "pngout.png" file that should be
+identical to it.  Look for "9782 zero samples" in the output of the
+test.  For more confidence, you can run another test by typing
+"pngtest pngnow.png" and looking for "289 zero samples" in the output.
+Also, you can run "pngtest -m contrib/pngsuite/*.png" and compare
+your output with the result shown in contrib/pngsuite/README.
+
+Most of the makefiles used to allow you to run "make install" to put
+the library in its final resting place, but that feature is no longer
+supported.  The only tested and supported manners to install libpng are
+the conventional build and install procedures driven by the configure
+script or by the CMake file.
+
+VIII. Configuring for DOS and other 16-bit platforms
+
+Officially, the support for 16-bit platforms has been removed.
+
+For DOS users who only have access to the lower 640K, you will
+have to limit zlib's memory usage via a png_set_compression_mem_level()
+call.  See zlib.h or zconf.h in the zlib library for more information.
+
+You may be or may not be in luck if you target the "large" memory model,
+but all the smaller models ("small", "compact" and "medium") are known
+to be unworkable.  For DOS users who have access beyond the lower 640K,
+a "flat" 32-bit DOS model (such as DJGPP) is strongly recommended.
+
+For DOS users who only have access to the lower 640K, you will have to
+limit zlib's memory usage via a png_set_compression_mem_level() call.
+You will also have to look into zconf.h to tell zlib (and thus libpng)
+that it cannot allocate more than 64K at a time.  Even if you can, the
+memory won't be accessible.  Therefore, you should limit zlib and libpng
+to 64K by defining MAXSEG_64K.
+
+IX. Prepending a prefix to exported symbols
+
+Starting with libpng-1.6.0, you can configure libpng (when using the
+"configure" script) to prefix all exported symbols by means of the
+configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any
+string beginning with a letter and containing only uppercase
+and lowercase letters, digits, and the underscore (i.e., a C language
+identifier).  This creates a set of macros in pnglibconf.h, so this is
+transparent to applications; their function calls get transformed by
+the macros to use the modified names.
+
+X. Configuring for compiler xxx:
+
+All includes for libpng are in pngconf.h.  If you need to add, change
+or delete an include, this is the place to do it.
+The includes that are not needed outside libpng are placed in pngpriv.h,
+which is only used by the routines inside libpng itself.
+The files in libpng proper only include pngpriv.h and png.h, which
+in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
+As of libpng-1.5.0, pngpriv.h also includes three other private header
+files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
+that previously appeared in the public headers.
+
+XI. Removing unwanted object code
+
+There are a bunch of #define's in pngconf.h that control what parts of
+libpng are compiled.  All the defines end in _SUPPORTED.  If you are
+never going to use a capability, you can change the #define to #undef
+before recompiling libpng and save yourself code and data space, or
+you can turn off individual capabilities with defines that begin with
+"PNG_NO_".
+
+In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
+
+You can also turn all of the transforms and ancillary chunk capabilities
+off en masse with compiler directives that define
+PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
+or all four, along with directives to turn on any of the capabilities that
+you do want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the
+extra transformations but still leave the library fully capable of reading
+and writing PNG files with all known public chunks. Use of the
+PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
+that is incapable of reading or writing ancillary chunks.  If you are
+not using the progressive reading capability, you can turn that off
+with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
+capability, which you'll still have).
+
+All the reading and writing specific code are in separate files, so the
+linker should only grab the files it needs.  However, if you want to
+make sure, or if you are building a stand alone library, all the
+reading files start with "pngr" and all the writing files start with "pngw".
+The files that don't match either (like png.c, pngtrans.c, etc.)
+are used for both reading and writing, and always need to be included.
+The progressive reader is in pngpread.c
+
+If you are creating or distributing a dynamically linked library (a .so
+or DLL file), you should not remove or disable any parts of the library,
+as this will cause applications linked with different versions of the
+library to fail if they call functions not available in your library.
+The size of the library itself should not be an issue, because only
+those sections that are actually used will be loaded into memory.
+
+XII. Enabling or disabling hardware optimizations
+
+Certain hardware capabilities, such as the Intel SSE instructions,
+are normally detected at run time. Enable them with configure options
+such as one of
+
+   --enable-arm-neon=yes
+   --enable-mips-msa=yes
+   --enable-intel-sse=yes
+   --enable-powerpc-vsx=yes
+
+or enable them all at once with
+
+   --enable-hardware-optimizations=yes
+
+or, if you are not using "configure", you can use one
+or more of
+
+   CPPFLAGS += "-DPNG_ARM_NEON"
+   CPPFLAGS += "-DPNG_MIPS_MSA"
+   CPPFLAGS += "-DPNG_INTEL_SSE"
+   CPPFLAGS += "-DPNG_POWERPC_VSX"
+
+See for example scripts/makefile.linux-opt
+
+If you wish to avoid using them,
+you can disable them via the configure option
+
+   --disable-hardware-optimizations
+
+to disable them all, or
+
+   --enable-intel-sse=no
+
+to disable a particular one,
+or via compiler-command options such as
+
+   CPPFLAGS += "-DPNG_ARM_NEON_OPT=0, -DPNG_MIPS_MSA_OPT=0,
+   -DPNG_INTEL_SSE_OPT=0, -DPNG_POWERPC_VSX_OPT=0"
+
+If you are using cmake, hardware optimizations are "on"
+by default. To disable them, use
+
+    cmake . -DPNG_ARM_NEON=no -DPNG_INTEL_SSE=no \
+            -DPNG_MIPS_MSA=no -DPNG_POWERPC_VSX=no
+
+or disable them all at once with
+
+    cmake . -DPNG_HARDWARE_OPTIMIZATIONS=no
+
+XIII. Changes to the build and configuration of libpng in libpng-1.5.x
+
+Details of internal changes to the library code can be found in the CHANGES
+file and in the GIT repository logs.  These will be of no concern to the vast
+majority of library users or builders; however, the few who configure libpng
+to a non-default feature set may need to change how this is done.
+
+There should be no need for library builders to alter build scripts if
+these use the distributed build support - configure or the makefiles -
+however, users of the makefiles may care to update their build scripts
+to build pnglibconf.h where the corresponding makefile does not do so.
+
+Building libpng with a non-default configuration has changed completely.
+The old method using pngusr.h should still work correctly even though the
+way pngusr.h is used in the build has been changed; however, library
+builders will probably want to examine the changes to take advantage of
+new capabilities and to simplify their build system.
+
+A. Specific changes to library configuration capabilities
+
+The exact mechanism used to control attributes of API functions has
+changed.  A single set of operating system independent macro definitions
+is used and operating system specific directives are defined in
+pnglibconf.h
+
+As part of this the mechanism used to choose procedure call standards on
+those systems that allow a choice has been changed.  At present this only
+affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
+running on Intel processors.  As before, PNGAPI is defined where required
+to control the exported API functions; however, two new macros, PNGCBAPI
+and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
+(PNGCAPI) for functions that must match a C library prototype (currently
+only png_longjmp_ptr, which must match the C longjmp function.)  The new
+approach is documented in pngconf.h
+
+Despite these changes, libpng 1.5.0 only supports the native C function
+calling standard on those platforms tested so far ("__cdecl" on Microsoft
+Windows).  This is because the support requirements for alternative
+calling conventions seem to no longer exist.  Developers who find it
+necessary to set PNG_API_RULE to 1 should advise the mailing list
+(png-mng-implement) of this and library builders who use Openwatcom and
+therefore set PNG_API_RULE to 2 should also contact the mailing list.
+
+B. Changes to the configuration mechanism
+
+Prior to libpng-1.5.0 library builders who needed to configure libpng
+had either to modify the exported pngconf.h header file to add system
+specific configuration or had to write feature selection macros into
+pngusr.h and cause this to be included into pngconf.h by defining
+PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
+application built without PNG_USER_CONFIG defined would see the
+unmodified, default, libpng API and thus would probably fail to link.
+
+These mechanisms still work in the configure build and in any makefile
+build that builds pnglibconf.h, although the feature selection macros
+have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
+processed only once, at the time the exported header file pnglibconf.h is
+built.  pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
+after the build of pnglibconf.h and it is never included in an application
+build.
+
+The formerly used alternative of adding a list of feature macros to the
+CPPFLAGS setting in the build also still works; however, the macros will be
+copied to pnglibconf.h and this may produce macro redefinition warnings
+when the individual C files are compiled.
+
+All configuration now only works if pnglibconf.h is built from
+scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
+(the original author of awk) maintains C source code of that awk and this
+and all known later implementations (often called by subtly different
+names - nawk and gawk for example) are adequate to build pnglibconf.h.
+The Sun Microsystems (now Oracle) program 'awk' is an earlier version
+and does not work; this may also apply to other systems that have a
+functioning awk called 'nawk'.
+
+Configuration options are now documented in scripts/pnglibconf.dfa.  This
+file also includes dependency information that ensures a configuration is
+consistent; that is, if a feature is switched off, dependent features are
+also switched off.  As a recommended alternative to using feature macros in
+pngusr.h a system builder may also define equivalent options in pngusr.dfa
+(or, indeed, any file) and add that to the configuration by setting
+DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
+how to do this, and also illustrate a case where pngusr.h is still required.
+
+After you have built libpng, the definitions that were recorded in
+pnglibconf.h are available to your application (pnglibconf.h is included
+in png.h and gets installed alongside png.h and pngconf.h in your
+$PREFIX/include directory).  Do not edit pnglibconf.h after you have built
+libpng, because than the settings would not accurately reflect the settings
+that were used to build libpng.
+
+XIV. Setjmp/longjmp issues
+
+Libpng uses setjmp()/longjmp() for error handling.  Unfortunately setjmp()
+is known to be not thread-safe on some platforms and we don't know of
+any platform where it is guaranteed to be thread-safe.  Therefore, if
+your application is going to be using multiple threads, you should
+configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with
+-DPNG_NO_SETJMP on your compile line, or with
+
+    #undef PNG_SETJMP_SUPPORTED
+
+in your pnglibconf.h or pngusr.h.
+
+Starting with libpng-1.6.0, the library included a "simplified API".
+This requires setjmp/longjmp, so you must either build the library
+with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
+and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
+
+XV. Common linking failures
+
+If your application fails to find libpng or zlib entries while linking:
+
+  Be sure "-lz" appears after "-lpng" on your linking command.
+
+  Be sure you have built libpng, zlib, and your application for the
+  same platform (e.g., 32-bit or 64-bit).
+
+  If you are using the vstudio project, observe the WARNING in
+  project/vstudio/README.txt.
+
+XVI. Other sources of information about libpng:
+
+Further information can be found in the README and libpng-manual.txt
+files, in the individual makefiles, in png.h, and the manual pages
+libpng.3 and png.5.
+
+Copyright (c) 2022 Cosmin Truta
+Copyright (c) 1998-2002,2006-2016 Glenn Randers-Pehrson
+This document is released under the libpng license.
+For conditions of distribution and use, see the disclaimer
+and license in png.h.
Index: /trunk/src/libs/libpng-1.6.45/LICENSE
===================================================================
--- /trunk/src/libs/libpng-1.6.45/LICENSE	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/LICENSE	(revision 107811)
@@ -0,0 +1,134 @@
+COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
+=========================================
+
+PNG Reference Library License version 2
+---------------------------------------
+
+ * Copyright (c) 1995-2024 The PNG Reference Library Authors.
+ * Copyright (c) 2018-2024 Cosmin Truta.
+ * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson.
+ * Copyright (c) 1996-1997 Andreas Dilger.
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+
+The software is supplied "as is", without warranty of any kind,
+express or implied, including, without limitation, the warranties
+of merchantability, fitness for a particular purpose, title, and
+non-infringement.  In no event shall the Copyright owners, or
+anyone distributing the software, be liable for any damages or
+other liability, whether in contract, tort or otherwise, arising
+from, out of, or in connection with the software, or the use or
+other dealings in the software, even if advised of the possibility
+of such damage.
+
+Permission is hereby granted to use, copy, modify, and distribute
+this software, or portions hereof, for any purpose, without fee,
+subject to the following restrictions:
+
+ 1. The origin of this software must not be misrepresented; you
+    must not claim that you wrote the original software.  If you
+    use this software in a product, an acknowledgment in the product
+    documentation would be appreciated, but is not required.
+
+ 2. Altered source versions must be plainly marked as such, and must
+    not be misrepresented as being the original software.
+
+ 3. This Copyright notice may not be removed or altered from any
+    source or altered source distribution.
+
+
+PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
+-----------------------------------------------------------------------
+
+libpng versions 1.0.7, July 1, 2000, through 1.6.35, July 15, 2018 are
+Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson, are
+derived from libpng-1.0.6, and are distributed according to the same
+disclaimer and license as libpng-1.0.6 with the following individuals
+added to the list of Contributing Authors:
+
+    Simon-Pierre Cadieux
+    Eric S. Raymond
+    Mans Rullgard
+    Cosmin Truta
+    Gilles Vollant
+    James Yu
+    Mandar Sahastrabuddhe
+    Google Inc.
+    Vadim Barkov
+
+and with the following additions to the disclaimer:
+
+    There is no warranty against interference with your enjoyment of
+    the library or against infringement.  There is no warranty that our
+    efforts or the library will fulfill any of your particular purposes
+    or needs.  This library is provided with all faults, and the entire
+    risk of satisfactory quality, performance, accuracy, and effort is
+    with the user.
+
+Some files in the "contrib" directory and some configure-generated
+files that are distributed with libpng have other copyright owners, and
+are released under other open source licenses.
+
+libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
+Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
+libpng-0.96, and are distributed according to the same disclaimer and
+license as libpng-0.96, with the following individuals added to the
+list of Contributing Authors:
+
+    Tom Lane
+    Glenn Randers-Pehrson
+    Willem van Schaik
+
+libpng versions 0.89, June 1996, through 0.96, May 1997, are
+Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
+and are distributed according to the same disclaimer and license as
+libpng-0.88, with the following individuals added to the list of
+Contributing Authors:
+
+    John Bowler
+    Kevin Bracey
+    Sam Bushell
+    Magnus Holmgren
+    Greg Roelofs
+    Tom Tanner
+
+Some files in the "scripts" directory have other copyright owners,
+but are released under this license.
+
+libpng versions 0.5, May 1995, through 0.88, January 1996, are
+Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+
+For the purposes of this copyright and license, "Contributing Authors"
+is defined as the following set of individuals:
+
+    Andreas Dilger
+    Dave Martindale
+    Guy Eric Schalnat
+    Paul Schmidt
+    Tim Wegner
+
+The PNG Reference Library is supplied "AS IS".  The Contributing
+Authors and Group 42, Inc. disclaim all warranties, expressed or
+implied, including, without limitation, the warranties of
+merchantability and of fitness for any purpose.  The Contributing
+Authors and Group 42, Inc. assume no liability for direct, indirect,
+incidental, special, exemplary, or consequential damages, which may
+result from the use of the PNG Reference Library, even if advised of
+the possibility of such damage.
+
+Permission is hereby granted to use, copy, modify, and distribute this
+source code, or portions hereof, for any purpose, without fee, subject
+to the following restrictions:
+
+ 1. The origin of this source code must not be misrepresented.
+
+ 2. Altered versions must be plainly marked as such and must not
+    be misrepresented as being the original source.
+
+ 3. This Copyright notice may not be removed or altered from any
+    source or altered source distribution.
+
+The Contributing Authors and Group 42, Inc. specifically permit,
+without fee, and encourage the use of this source code as a component
+to supporting the PNG file format in commercial products.  If you use
+this source code in a product, acknowledgment is not required but would
+be appreciated.
Index: /trunk/src/libs/libpng-1.6.45/Makefile.am
===================================================================
--- /trunk/src/libs/libpng-1.6.45/Makefile.am	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/Makefile.am	(revision 107811)
@@ -0,0 +1,426 @@
+# Makefile.am, the source file for Makefile.in (and hence Makefile), is
+#
+# Copyright (c) 2018-2024 Cosmin Truta
+# Copyright (c) 2004-2016 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+
+ACLOCAL_AMFLAGS = -I scripts/autoconf
+
+# test programs - run on make check, make distcheck
+if ENABLE_TESTS
+check_PROGRAMS= pngtest pngunknown pngstest pngvalid pngimage pngcp
+if HAVE_CLOCK_GETTIME
+check_PROGRAMS += timepng
+endif
+else
+check_PROGRAMS=
+endif
+
+# Utilities - installed
+if ENABLE_TOOLS
+bin_PROGRAMS= pngfix png-fix-itxt
+else
+bin_PROGRAMS=
+endif
+
+# This ensures that pnglibconf.h gets built at the start of 'make all' or
+# 'make check', but it does not add dependencies to the individual programs,
+# this is done below.
+#
+# IMPORTANT: always add the object modules of new programs to the list below
+# because otherwise the sequence 'configure; make new-program' will *sometimes*
+# result in the installed (system) pnglibconf.h being used and the result is
+# always wrong and always very confusing.
+BUILT_SOURCES = pnglibconf.h
+
+if ENABLE_TESTS
+pngtest_SOURCES = pngtest.c
+pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngvalid_SOURCES = contrib/libtests/pngvalid.c
+pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngstest_SOURCES = contrib/libtests/pngstest.c
+pngstest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngunknown_SOURCES = contrib/libtests/pngunknown.c
+pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngimage_SOURCES = contrib/libtests/pngimage.c
+pngimage_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+timepng_SOURCES = contrib/libtests/timepng.c
+timepng_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+pngcp_SOURCES = contrib/tools/pngcp.c
+pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+endif
+
+if ENABLE_TOOLS
+pngfix_SOURCES = contrib/tools/pngfix.c
+pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+
+png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c
+endif
+
+# Generally these are single line shell scripts to run a test with a particular
+# set of parameters:
+if ENABLE_TESTS
+TESTS =\
+   tests/pngtest-all\
+   tests/pngvalid-gamma-16-to-8 tests/pngvalid-gamma-alpha-mode\
+   tests/pngvalid-gamma-background tests/pngvalid-gamma-expand16-alpha-mode\
+   tests/pngvalid-gamma-expand16-background\
+   tests/pngvalid-gamma-expand16-transform tests/pngvalid-gamma-sbit\
+   tests/pngvalid-gamma-threshold tests/pngvalid-gamma-transform\
+   tests/pngvalid-progressive-size\
+   tests/pngvalid-progressive-interlace-standard\
+   tests/pngvalid-transform\
+   tests/pngvalid-progressive-standard tests/pngvalid-standard\
+   tests/pngstest-1.8 tests/pngstest-1.8-alpha tests/pngstest-linear\
+   tests/pngstest-linear-alpha tests/pngstest-none tests/pngstest-none-alpha\
+   tests/pngstest-sRGB tests/pngstest-sRGB-alpha tests/pngunknown-IDAT\
+   tests/pngunknown-discard tests/pngunknown-if-safe tests/pngunknown-sAPI\
+   tests/pngunknown-sTER tests/pngunknown-save tests/pngunknown-vpAg\
+   tests/pngimage-quick tests/pngimage-full
+endif
+
+# man pages
+dist_man_MANS= libpng.3 libpngpf.3 png.5
+
+# generate the -config scripts if required
+binconfigs= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
+EXTRA_SCRIPTS= libpng-config libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
+bin_SCRIPTS= @binconfigs@
+
+# rules to build libpng, only build the old library on request
+lib_LTLIBRARIES=libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+# EXTRA_LTLIBRARIES= libpng.la
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c\
+	pngget.c pngmem.c pngpread.c pngread.c pngrio.c pngrtran.c pngrutil.c\
+	pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c\
+	png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h pngusr.dfa
+
+if PNG_ARM_NEON
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += arm/arm_init.c\
+	arm/filter_neon.S arm/filter_neon_intrinsics.c \
+	arm/palette_neon_intrinsics.c
+endif
+
+if PNG_MIPS_MSA
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += mips/mips_init.c\
+	mips/filter_msa_intrinsics.c
+endif
+
+if PNG_MIPS_MMI
+if !PNG_MIPS_MSA
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += mips/mips_init.c
+endif
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += mips/filter_mmi_inline_assembly.c
+endif
+
+if PNG_INTEL_SSE
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += intel/intel_init.c\
+	intel/filter_sse2_intrinsics.c
+endif
+
+if PNG_POWERPC_VSX
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += powerpc/powerpc_init.c\
+        powerpc/filter_vsx_intrinsics.c
+endif
+
+if PNG_LOONGARCH_LSX
+noinst_LTLIBRARIES= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_SOURCES = loongarch/loongarch_lsx_init.c\
+	loongarch/filter_lsx_intrinsics.c
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_CFLAGS = -mlsx
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+# libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+endif
+
+nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
+
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined -export-dynamic \
+	-version-number @PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0
+
+if HAVE_LD_VERSION_SCRIPT
+#   Versioned symbols and restricted exports
+if HAVE_SOLARIS_LD
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,-M -Wl,libpng.vers
+else
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,--version-script=libpng.vers
+endif
+
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.vers
+else
+#   Only restricted exports when possible
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -export-symbols libpng.sym
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.sym
+endif
+
+if PNG_LOONGARCH_LSX
+  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES += libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+endif
+
+#distribute headers in /usr/include/libpng/*
+pkgincludedir= $(includedir)/$(PNGLIB_BASENAME)
+pkginclude_HEADERS= png.h pngconf.h
+nodist_pkginclude_HEADERS= pnglibconf.h
+
+# pkg-config stuff, note that libpng.pc is always required in order
+# to get the correct library
+pkgconfigdir = @pkgconfigdir@
+pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc
+
+# Extra source distribution files, '${srcdir}' is used below to stop build files
+# from those directories being included.  This only works if the configure is
+# not done in the source directory!
+EXTRA_DIST= \
+	ANNOUNCE AUTHORS CHANGES INSTALL LICENSE README TODO TRADEMARK \
+	pngtest.png pngbar.png pngnow.png pngbar.jpg autogen.sh \
+	${srcdir}/ci ${srcdir}/contrib ${srcdir}/projects ${srcdir}/scripts \
+	$(TESTS) $(XFAIL_TESTS) tests/pngstest \
+	CMakeLists.txt example.c libpng-manual.txt
+
+SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk
+
+CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
+	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
+	check.new pnglibconf.h pngprefix.h symbols.new pngtest-log.txt \
+	pnglibconf.out pnglibconf.c pnglibconf.pre pnglibconf.dfn \
+	$(SCRIPT_CLEANFILES)
+
+MAINTAINERCLEANFILES = Makefile.in aclocal.m4 config.guess config.h.in \
+config.sub configure depcomp install-sh ltmain.sh missing
+
+# PNG_COPTS give extra options for the C compiler to be used on all compilation
+# steps (unless targe_CFLAGS is specified; that will take precedence over
+# AM_CFLAGS)
+PNG_COPTS = @PNG_COPTS@
+AM_CFLAGS = ${PNG_COPTS}
+
+# DFNCPP is normally just CPP - the C preprocessor - but on Solaris and maybe
+# other operating systems (NeXT?) the C preprocessor selected by configure
+# checks input tokens for validity - effectively it performs part of the ANSI-C
+# parsing - and therefore fails with the .df files.  configure.ac has special
+# checks for this and sets DFNCPP appropriately.
+DFNCPP = @DFNCPP@
+
+SUFFIXES = .chk .out
+
+$(PNGLIB_BASENAME).pc: libpng.pc
+	cp libpng.pc $@
+
+$(PNGLIB_BASENAME)-config: libpng-config
+	cp libpng-config $@
+
+scripts/sym.out scripts/vers.out: png.h pngconf.h pnglibconf.h
+scripts/prefix.out: png.h pngconf.h pnglibconf.out
+scripts/symbols.out: png.h pngconf.h $(srcdir)/scripts/pnglibconf.h.prebuilt
+scripts/intprefix.out: pnglibconf.h
+
+libpng.sym: scripts/sym.out
+	rm -f $@
+	cp $? $@
+libpng.vers: scripts/vers.out
+	rm -f $@
+	cp $? $@
+
+if DO_PNG_PREFIX
+# Rename functions in scripts/prefix.out with a PNG_PREFIX prefix.
+# Rename macros in scripts/macro.lst from PNG_PREFIXpng_ to PNG_ (the actual
+# implementation of the macro).
+pnglibconf.h: pnglibconf.out scripts/prefix.out scripts/macro.lst
+	rm -f $@
+	$(AWK) 's==0 && NR>1{print prev}\
+	   s==0{prev=$$0}\
+	   s==1{print "#define", $$1, "@PNG_PREFIX@" $$1}\
+	   s==2{print "#define @PNG_PREFIX@png_" $$1, "PNG_" $$1}\
+	   END{print prev}' s=0 pnglibconf.out s=1 scripts/prefix.out\
+	   s=2 ${srcdir}/scripts/macro.lst >pnglibconf.tf8
+	mv pnglibconf.tf8 $@
+
+pngprefix.h: scripts/intprefix.out
+	rm -f pngprefix.tf1
+	$(AWK) '{print "#define", $$1, "@PNG_PREFIX@" $$1}' $? >pngprefix.tf1
+	mv pngprefix.tf1 $@
+else
+pnglibconf.h: pnglibconf.out
+	rm -f $@
+	cp $? $@
+
+pngprefix.h: # is empty
+	:>$@
+endif
+
+$(srcdir)/scripts/pnglibconf.h.prebuilt:
+	@echo "Attempting to build $@" >&2
+	@echo "This is a machine generated file, but if you want to make" >&2
+	@echo "a new one simply make 'scripts/pnglibconf.out', copy that" >&2
+	@echo "AND set PNG_ZLIB_VERNUM to 0 (you MUST do this)" >&2
+	@exit 1
+
+# The following is necessary to ensure that the local pnglibconf.h is used, not
+# an installed one (this can happen immediately after on a clean system if
+# 'make test' is the first thing the user does.)  Only files which include
+# one of the png source files (typically png.h or pngpriv.h) need to be listed
+# here:
+pngtest.o: pnglibconf.h
+
+contrib/libtests/makepng.o: pnglibconf.h
+contrib/libtests/pngstest.o: pnglibconf.h
+contrib/libtests/pngunknown.o: pnglibconf.h
+contrib/libtests/pngimage.o: pnglibconf.h
+contrib/libtests/pngvalid.o: pnglibconf.h
+contrib/libtests/readpng.o: pnglibconf.h
+contrib/libtests/tarith.o: pnglibconf.h
+contrib/libtests/timepng.o: pnglibconf.h
+
+contrib/tools/makesRGB.o: pnglibconf.h
+contrib/tools/pngfix.o: pnglibconf.h
+contrib/tools/pngcp.o: pnglibconf.h
+
+# We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
+# be built with PNG_USE_READ_MACROS; this prevents the read macros from
+# interfering with the symbol file format.
+SYMBOL_CFLAGS = -DPNGLIB_LIBNAME='PNG@PNGLIB_MAJOR@@PNGLIB_MINOR@_0'\
+		-DPNGLIB_VERSION='@PNGLIB_VERSION@'\
+		-DSYMBOL_PREFIX='$(SYMBOL_PREFIX)'\
+		-DPNG_NO_USE_READ_MACROS -DPNG_BUILDING_SYMBOL_TABLE
+
+if DO_PNG_PREFIX
+SYMBOL_CFLAGS += -DPNG_PREFIX='@PNG_PREFIX@'
+endif
+
+.c.out:
+	rm -f $@ $*.tf[12]
+	test -d scripts || mkdir scripts || test -d scripts
+	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES)\
+	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $< > $*.tf1
+	$(AWK) -f "${srcdir}/scripts/dfn.awk" out="$*.tf2" $*.tf1 1>&2
+	rm -f $*.tf1
+	mv $*.tf2 $@
+
+# The .c file for pnglibconf.h is machine generated
+pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+	rm -f $@ $*.tf[45]
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf4 version=search\
+	    ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+	    ${srcdir}/pngusr.dfa $(DFA_XTRA) 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf5 $*.tf4 1>&2
+	rm $*.tf4
+	mv $*.tf5 $@
+
+# Symbol checks (.def and .out files should match)
+scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.out
+
+.out.chk:
+	rm -f $@ $*.new
+	$(AWK) -f ${srcdir}/scripts/checksym.awk ${srcdir}/scripts/${*F}.def\
+	    of="$*.new" $< >&2
+	mv $*.new $@
+
+# used on demand to regenerate the standard header, CPPFLAGS should
+# be empty - no non-standard defines
+scripts/pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
+	rm -f $@ pnglibconf.tf[67]
+	test -z "$(CPPFLAGS)"
+	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf6\
+	    logunsupported=1 version=search ${srcdir}/pngconf.h -\
+	    ${srcdir}/scripts/pnglibconf.dfa 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf7\
+	    pnglibconf.tf6 1>&2
+	rm pnglibconf.tf6
+	mv pnglibconf.tf7 $@
+
+$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS): png.h pngconf.h \
+	pnglibconf.h pngpriv.h pngdebug.h pnginfo.h pngstruct.h pngprefix.h
+
+test: check-am
+
+# Extra checks
+check: scripts/symbols.chk
+
+# Don't distribute the generated script files
+dist-hook:
+	cd '$(top_distdir)'; rm -f $(SCRIPT_CLEANFILES)
+
+# Make links between installed files with release-specific names and the generic
+# file names.  If this install rule is run the generic names will be deleted and
+# recreated - this has obvious issues for systems with multiple installations.
+
+install-header-links:
+	@set -ex; cd '$(DESTDIR)$(includedir)'; for f in $(HEADERS); do \
+	   rm -f "$$f"; $(LN_S) "$(PNGLIB_BASENAME)/$$f" "$$f"; done
+
+uninstall-header-links:
+	cd '$(DESTDIR)$(includedir)'; rm -f $(HEADERS)
+
+install-libpng-pc:
+	@set -ex; cd '$(DESTDIR)$(pkgconfigdir)'; rm -f libpng.pc; \
+	   $(LN_S) '$(PNGLIB_BASENAME).pc' libpng.pc
+
+uninstall-libpng-pc:
+	rm -f '$(DESTDIR)$(pkgconfigdir)/libpng.pc'
+
+# EXT_LIST is a list of the possibly library directory extensions, this exists
+# because we can't find a good way of discovering the file extensions that are
+# actually installed on a given system, so instead we check for every extension
+# we have seen.
+
+EXT_LIST = a dll.a so so.@PNGLIB_MAJOR@@PNGLIB_MINOR@.@PNGLIB_RELEASE@ la sl dylib
+
+install-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)';\
+	for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext";\
+           if test -f "$(PNGLIB_BASENAME).$$ext"; then\
+              $(LN_S) "$(PNGLIB_BASENAME).$$ext" "libpng.$$ext" || exit 1;\
+           fi;\
+	done
+
+uninstall-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)'; for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext"; done
+
+install-libpng-config:
+	@set -ex; cd '$(DESTDIR)$(bindir)'; rm -f libpng-config; \
+	   $(LN_S) '$(PNGLIB_BASENAME)-config' libpng-config
+
+uninstall-libpng-config:
+	rm -f '$(DESTDIR)$(bindir)/libpng-config'
+
+if DO_INSTALL_LINKS
+# If --enable-unversioned-links is specified the header and lib file links
+# will be automatically made on a 'make install':
+
+install-data-hook: install-header-links
+uninstall-hook: uninstall-header-links
+install-exec-hook: install-library-links
+uninstall-hook: uninstall-library-links
+endif
+
+if DO_INSTALL_LIBPNG_PC
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Index: /trunk/src/libs/libpng-1.6.45/Makefile.in
===================================================================
--- /trunk/src/libs/libpng-1.6.45/Makefile.in	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/Makefile.in	(revision 107811)
@@ -0,0 +1,2550 @@
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+	$(pngimage_SOURCES) $(pngstest_SOURCES) $(pngtest_SOURCES) \
+	$(pngunknown_SOURCES) $(pngvalid_SOURCES) $(timepng_SOURCES)
+DIST_SOURCES =  \
+	$(am__libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES_DIST) \
+	$(am__libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_SOURCES_DIST) \
+	$(am__png_fix_itxt_SOURCES_DIST) $(am__pngcp_SOURCES_DIST) \
+	$(am__pngfix_SOURCES_DIST) $(am__pngimage_SOURCES_DIST) \
+	$(am__pngstest_SOURCES_DIST) $(am__pngtest_SOURCES_DIST) \
+	$(am__pngunknown_SOURCES_DIST) $(am__pngvalid_SOURCES_DIST) \
+	$(am__timepng_SOURCES_DIST)
+am__can_run_installinfo = \
+  case $$AM_UPDATE_INFO_DIR in \
+    n|no|NO) false;; \
+    *) (install-info --version) >/dev/null 2>&1;; \
+  esac
+man3dir = $(mandir)/man3
+man5dir = $(mandir)/man5
+NROFF = nroff
+MANS = $(dist_man_MANS)
+DATA = $(pkgconfig_DATA)
+HEADERS = $(nodist_pkginclude_HEADERS) $(pkginclude_HEADERS)
+am__tagged_files = $(HEADERS) $(SOURCES) $(TAGS_FILES) $(LISP) \
+	config.h.in
+# Read a list of newline-separated strings from the standard input,
+# and print each of them once, without duplicates.  Input order is
+# *not* preserved.
+am__uniquify_input = $(AWK) '\
+  BEGIN { nonempty = 0; } \
+  { items[$$0] = 1; nonempty = 1; } \
+  END { if (nonempty) { for (i in items) print i; }; } \
+'
+# Make sure the list of sources is unique.  This is necessary because,
+# e.g., the same source file might be shared among _SOURCES variables
+# for different programs/libraries.
+am__define_uniq_tagged_files = \
+  list='$(am__tagged_files)'; \
+  unique=`for i in $$list; do \
+    if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
+  done | $(am__uniquify_input)`
+AM_RECURSIVE_TARGETS = cscope check recheck
+am__tty_colors_dummy = \
+  mgn= red= grn= lgn= blu= brg= std=; \
+  am__color_tests=no
+am__tty_colors = { \
+  $(am__tty_colors_dummy); \
+  if test "X$(AM_COLOR_TESTS)" = Xno; then \
+    am__color_tests=no; \
+  elif test "X$(AM_COLOR_TESTS)" = Xalways; then \
+    am__color_tests=yes; \
+  elif test "X$$TERM" != Xdumb && { test -t 1; } 2>/dev/null; then \
+    am__color_tests=yes; \
+  fi; \
+  if test $$am__color_tests = yes; then \
+    red='[0;31m'; \
+    grn='[0;32m'; \
+    lgn='[1;32m'; \
+    blu='[1;34m'; \
+    mgn='[0;35m'; \
+    brg='[1m'; \
+    std='[m'; \
+  fi; \
+}
+am__recheck_rx = ^[ 	]*:recheck:[ 	]*
+am__global_test_result_rx = ^[ 	]*:global-test-result:[ 	]*
+am__copy_in_global_log_rx = ^[ 	]*:copy-in-global-log:[ 	]*
+# A command that, given a newline-separated list of test names on the
+# standard input, print the name of the tests that are to be re-run
+# upon "make recheck".
+am__list_recheck_tests = $(AWK) '{ \
+  recheck = 1; \
+  while ((rc = (getline line < ($$0 ".trs"))) != 0) \
+    { \
+      if (rc < 0) \
+        { \
+          if ((getline line2 < ($$0 ".log")) < 0) \
+	    recheck = 0; \
+          break; \
+        } \
+      else if (line ~ /$(am__recheck_rx)[nN][Oo]/) \
+        { \
+          recheck = 0; \
+          break; \
+        } \
+      else if (line ~ /$(am__recheck_rx)[yY][eE][sS]/) \
+        { \
+          break; \
+        } \
+    }; \
+  if (recheck) \
+    print $$0; \
+  close ($$0 ".trs"); \
+  close ($$0 ".log"); \
+}'
+# A command that, given a newline-separated list of test names on the
+# standard input, create the global log from their .trs and .log files.
+am__create_global_log = $(AWK) ' \
+function fatal(msg) \
+{ \
+  print "fatal: making $@: " msg | "cat >&2"; \
+  exit 1; \
+} \
+function rst_section(header) \
+{ \
+  print header; \
+  len = length(header); \
+  for (i = 1; i <= len; i = i + 1) \
+    printf "="; \
+  printf "\n\n"; \
+} \
+{ \
+  copy_in_global_log = 1; \
+  global_test_result = "RUN"; \
+  while ((rc = (getline line < ($$0 ".trs"))) != 0) \
+    { \
+      if (rc < 0) \
+         fatal("failed to read from " $$0 ".trs"); \
+      if (line ~ /$(am__global_test_result_rx)/) \
+        { \
+          sub("$(am__global_test_result_rx)", "", line); \
+          sub("[ 	]*$$", "", line); \
+          global_test_result = line; \
+        } \
+      else if (line ~ /$(am__copy_in_global_log_rx)[nN][oO]/) \
+        copy_in_global_log = 0; \
+    }; \
+  if (copy_in_global_log) \
+    { \
+      rst_section(global_test_result ": " $$0); \
+      while ((rc = (getline line < ($$0 ".log"))) != 0) \
+      { \
+        if (rc < 0) \
+          fatal("failed to read from " $$0 ".log"); \
+        print line; \
+      }; \
+      printf "\n"; \
+    }; \
+  close ($$0 ".trs"); \
+  close ($$0 ".log"); \
+}'
+# Restructured Text title.
+am__rst_title = { sed 's/.*/   &   /;h;s/./=/g;p;x;s/ *$$//;p;g' && echo; }
+# Solaris 10 'make', and several other traditional 'make' implementations,
+# pass "-e" to $(SHELL), and POSIX 2008 even requires this.  Work around it
+# by disabling -e (using the XSI extension "set +e") if it's set.
+am__sh_e_setup = case $$- in *e*) set +e;; esac
+# Default flags passed to test drivers.
+am__common_driver_flags = \
+  --color-tests "$$am__color_tests" \
+  --enable-hard-errors "$$am__enable_hard_errors" \
+  --expect-failure "$$am__expect_failure"
+# To be inserted before the command running the test.  Creates the
+# directory for the log if needed.  Stores in $dir the directory
+# containing $f, in $tst the test, in $log the log.  Executes the
+# developer- defined test setup AM_TESTS_ENVIRONMENT (if any), and
+# passes TESTS_ENVIRONMENT.  Set up options for the wrapper that
+# will run the test scripts (or their associated LOG_COMPILER, if
+# thy have one).
+am__check_pre = \
+$(am__sh_e_setup);					\
+$(am__vpath_adj_setup) $(am__vpath_adj)			\
+$(am__tty_colors);					\
+srcdir=$(srcdir); export srcdir;			\
+case "$@" in						\
+  */*) am__odir=`echo "./$@" | sed 's|/[^/]*$$||'`;;	\
+    *) am__odir=.;; 					\
+esac;							\
+test "x$$am__odir" = x"." || test -d "$$am__odir" 	\
+  || $(MKDIR_P) "$$am__odir" || exit $$?;		\
+if test -f "./$$f"; then dir=./;			\
+elif test -f "$$f"; then dir=;				\
+else dir="$(srcdir)/"; fi;				\
+tst=$$dir$$f; log='$@'; 				\
+if test -n '$(DISABLE_HARD_ERRORS)'; then		\
+  am__enable_hard_errors=no; 				\
+else							\
+  am__enable_hard_errors=yes; 				\
+fi; 							\
+case " $(XFAIL_TESTS) " in				\
+  *[\ \	]$$f[\ \	]* | *[\ \	]$$dir$$f[\ \	]*) \
+    am__expect_failure=yes;;				\
+  *)							\
+    am__expect_failure=no;;				\
+esac; 							\
+$(AM_TESTS_ENVIRONMENT) $(TESTS_ENVIRONMENT)
+# A shell command to get the names of the tests scripts with any registered
+# extension removed (i.e., equivalently, the names of the test logs, with
+# the '.log' extension removed).  The result is saved in the shell variable
+# '$bases'.  This honors runtime overriding of TESTS and TEST_LOGS.  Sadly,
+# we cannot use something simpler, involving e.g., "$(TEST_LOGS:.log=)",
+# since that might cause problem with VPATH rewrites for suffix-less tests.
+# See also 'test-harness-vpath-rewrite.sh' and 'test-trs-basic.sh'.
+am__set_TESTS_bases = \
+  bases='$(TEST_LOGS)'; \
+  bases=`for i in $$bases; do echo $$i; done | sed 's/\.log$$//'`; \
+  bases=`echo $$bases`
+AM_TESTSUITE_SUMMARY_HEADER = ' for $(PACKAGE_STRING)'
+RECHECK_LOGS = $(TEST_LOGS)
+TEST_SUITE_LOG = test-suite.log
+TEST_EXTENSIONS = @EXEEXT@ .test
+LOG_DRIVER = $(SHELL) $(top_srcdir)/test-driver
+LOG_COMPILE = $(LOG_COMPILER) $(AM_LOG_FLAGS) $(LOG_FLAGS)
+am__set_b = \
+  case '$@' in \
+    */*) \
+      case '$*' in \
+        */*) b='$*';; \
+          *) b=`echo '$@' | sed 's/\.log$$//'`; \
+       esac;; \
+    *) \
+      b='$*';; \
+  esac
+am__test_logs1 = $(TESTS:=.log)
+am__test_logs2 = $(am__test_logs1:@EXEEXT@.log=.log)
+TEST_LOGS = $(am__test_logs2:.test.log=.log)
+TEST_LOG_DRIVER = $(SHELL) $(top_srcdir)/test-driver
+TEST_LOG_COMPILE = $(TEST_LOG_COMPILER) $(AM_TEST_LOG_FLAGS) \
+	$(TEST_LOG_FLAGS)
+am__DIST_COMMON = $(dist_man_MANS) $(srcdir)/Makefile.in \
+	$(srcdir)/config.h.in $(srcdir)/libpng-config.in \
+	$(srcdir)/libpng.pc.in AUTHORS INSTALL README TODO compile \
+	config.guess config.sub depcomp install-sh ltmain.sh missing \
+	test-driver
+DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
+distdir = $(PACKAGE)-$(VERSION)
+top_distdir = $(distdir)
+am__remove_distdir = \
+  if test -d "$(distdir)"; then \
+    find "$(distdir)" -type d ! -perm -200 -exec chmod u+w {} ';' \
+      && rm -rf "$(distdir)" \
+      || { sleep 5 && rm -rf "$(distdir)"; }; \
+  else :; fi
+am__post_remove_distdir = $(am__remove_distdir)
+DIST_ARCHIVES = $(distdir).tar.gz $(distdir).tar.xz
+GZIP_ENV = --best
+DIST_TARGETS = dist-xz dist-gzip
+# Exists only to be overridden by the user if desired.
+AM_DISTCHECK_DVI_TARGET = dvi
+distuninstallcheck_listfiles = find . -type f -print
+am__distuninstallcheck_listfiles = $(distuninstallcheck_listfiles) \
+  | sed 's|^\./|$(prefix)/|' | grep -v '$(infodir)/dir$$'
+distcleancheck_listfiles = find . -type f -print
+
+#distribute headers in /usr/include/libpng/*
+pkgincludedir = $(includedir)/$(PNGLIB_BASENAME)
+ACLOCAL = @ACLOCAL@
+AMTAR = @AMTAR@
+AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+AR = @AR@
+AS = @AS@
+AUTOCONF = @AUTOCONF@
+AUTOHEADER = @AUTOHEADER@
+AUTOMAKE = @AUTOMAKE@
+AWK = @AWK@
+CC = @CC@
+CCAS = @CCAS@
+CCASDEPMODE = @CCASDEPMODE@
+CCASFLAGS = @CCASFLAGS@
+CCDEPMODE = @CCDEPMODE@
+CFLAGS = @CFLAGS@
+CPP = @CPP@
+CPPFLAGS = @CPPFLAGS@
+CSCOPE = @CSCOPE@
+CTAGS = @CTAGS@
+CYGPATH_W = @CYGPATH_W@
+DEFS = @DEFS@
+DEPDIR = @DEPDIR@
+
+# DFNCPP is normally just CPP - the C preprocessor - but on Solaris and maybe
+# other operating systems (NeXT?) the C preprocessor selected by configure
+# checks input tokens for validity - effectively it performs part of the ANSI-C
+# parsing - and therefore fails with the .df files.  configure.ac has special
+# checks for this and sets DFNCPP appropriately.
+DFNCPP = @DFNCPP@
+DLLTOOL = @DLLTOOL@
+DSYMUTIL = @DSYMUTIL@
+DUMPBIN = @DUMPBIN@
+ECHO_C = @ECHO_C@
+ECHO_N = @ECHO_N@
+ECHO_T = @ECHO_T@
+EGREP = @EGREP@
+ETAGS = @ETAGS@
+EXEEXT = @EXEEXT@
+FGREP = @FGREP@
+FILECMD = @FILECMD@
+GREP = @GREP@
+INSTALL = @INSTALL@
+INSTALL_DATA = @INSTALL_DATA@
+INSTALL_PROGRAM = @INSTALL_PROGRAM@
+INSTALL_SCRIPT = @INSTALL_SCRIPT@
+INSTALL_STRIP_PROGRAM = @INSTALL_STRIP_PROGRAM@
+LD = @LD@
+LDFLAGS = @LDFLAGS@
+LIBOBJS = @LIBOBJS@
+LIBS = @LIBS@
+LIBTOOL = @LIBTOOL@
+LIPO = @LIPO@
+LN_S = @LN_S@
+LTLIBOBJS = @LTLIBOBJS@
+LT_SYS_LIBRARY_PATH = @LT_SYS_LIBRARY_PATH@
+MAINT = @MAINT@
+MAKEINFO = @MAKEINFO@
+MANIFEST_TOOL = @MANIFEST_TOOL@
+MKDIR_P = @MKDIR_P@
+NM = @NM@
+NMEDIT = @NMEDIT@
+OBJDUMP = @OBJDUMP@
+OBJEXT = @OBJEXT@
+OTOOL = @OTOOL@
+OTOOL64 = @OTOOL64@
+PACKAGE = @PACKAGE@
+PACKAGE_BUGREPORT = @PACKAGE_BUGREPORT@
+PACKAGE_NAME = @PACKAGE_NAME@
+PACKAGE_STRING = @PACKAGE_STRING@
+PACKAGE_TARNAME = @PACKAGE_TARNAME@
+PACKAGE_URL = @PACKAGE_URL@
+PACKAGE_VERSION = @PACKAGE_VERSION@
+PATH_SEPARATOR = @PATH_SEPARATOR@
+PNGLIB_MAJOR = @PNGLIB_MAJOR@
+PNGLIB_MINOR = @PNGLIB_MINOR@
+PNGLIB_RELEASE = @PNGLIB_RELEASE@
+PNGLIB_VERSION = @PNGLIB_VERSION@
+
+# PNG_COPTS give extra options for the C compiler to be used on all compilation
+# steps (unless targe_CFLAGS is specified; that will take precedence over
+# AM_CFLAGS)
+PNG_COPTS = @PNG_COPTS@
+PNG_PREFIX = @PNG_PREFIX@
+RANLIB = @RANLIB@
+SED = @SED@
+SET_MAKE = @SET_MAKE@
+SHELL = @SHELL@
+STRIP = @STRIP@
+SYMBOL_PREFIX = @SYMBOL_PREFIX@
+VERSION = @VERSION@
+abs_builddir = @abs_builddir@
+abs_srcdir = @abs_srcdir@
+abs_top_builddir = @abs_top_builddir@
+abs_top_srcdir = @abs_top_srcdir@
+ac_ct_AR = @ac_ct_AR@
+ac_ct_CC = @ac_ct_CC@
+ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+am__include = @am__include@
+am__leading_dot = @am__leading_dot@
+am__quote = @am__quote@
+am__tar = @am__tar@
+am__untar = @am__untar@
+
+# generate the -config scripts if required
+binconfigs = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
+bindir = @bindir@
+build = @build@
+build_alias = @build_alias@
+build_cpu = @build_cpu@
+build_os = @build_os@
+build_vendor = @build_vendor@
+builddir = @builddir@
+datadir = @datadir@
+datarootdir = @datarootdir@
+docdir = @docdir@
+dvidir = @dvidir@
+exec_prefix = @exec_prefix@
+host = @host@
+host_alias = @host_alias@
+host_cpu = @host_cpu@
+host_os = @host_os@
+host_vendor = @host_vendor@
+htmldir = @htmldir@
+includedir = @includedir@
+infodir = @infodir@
+install_sh = @install_sh@
+libdir = @libdir@
+libexecdir = @libexecdir@
+localedir = @localedir@
+localstatedir = @localstatedir@
+mandir = @mandir@
+mkdir_p = @mkdir_p@
+oldincludedir = @oldincludedir@
+pdfdir = @pdfdir@
+
+# pkg-config stuff, note that libpng.pc is always required in order
+# to get the correct library
+pkgconfigdir = @pkgconfigdir@
+prefix = @prefix@
+program_transform_name = @program_transform_name@
+psdir = @psdir@
+runstatedir = @runstatedir@
+sbindir = @sbindir@
+sharedstatedir = @sharedstatedir@
+srcdir = @srcdir@
+sysconfdir = @sysconfdir@
+target_alias = @target_alias@
+top_build_prefix = @top_build_prefix@
+top_builddir = @top_builddir@
+top_srcdir = @top_srcdir@
+PNGLIB_BASENAME = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+ACLOCAL_AMFLAGS = -I scripts/autoconf
+
+# This ensures that pnglibconf.h gets built at the start of 'make all' or
+# 'make check', but it does not add dependencies to the individual programs,
+# this is done below.
+#
+# IMPORTANT: always add the object modules of new programs to the list below
+# because otherwise the sequence 'configure; make new-program' will *sometimes*
+# result in the installed (system) pnglibconf.h being used and the result is
+# always wrong and always very confusing.
+BUILT_SOURCES = pnglibconf.h
+@ENABLE_TESTS_TRUE@pngtest_SOURCES = pngtest.c
+@ENABLE_TESTS_TRUE@pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+@ENABLE_TESTS_TRUE@pngvalid_SOURCES = contrib/libtests/pngvalid.c
+@ENABLE_TESTS_TRUE@pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+@ENABLE_TESTS_TRUE@pngstest_SOURCES = contrib/libtests/pngstest.c
+@ENABLE_TESTS_TRUE@pngstest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+@ENABLE_TESTS_TRUE@pngunknown_SOURCES = contrib/libtests/pngunknown.c
+@ENABLE_TESTS_TRUE@pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+@ENABLE_TESTS_TRUE@pngimage_SOURCES = contrib/libtests/pngimage.c
+@ENABLE_TESTS_TRUE@pngimage_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+@ENABLE_TESTS_TRUE@timepng_SOURCES = contrib/libtests/timepng.c
+@ENABLE_TESTS_TRUE@timepng_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+@ENABLE_TESTS_TRUE@pngcp_SOURCES = contrib/tools/pngcp.c
+@ENABLE_TESTS_TRUE@pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+@ENABLE_TOOLS_TRUE@pngfix_SOURCES = contrib/tools/pngfix.c
+@ENABLE_TOOLS_TRUE@pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+@ENABLE_TOOLS_TRUE@png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c
+
+# Generally these are single line shell scripts to run a test with a particular
+# set of parameters:
+@ENABLE_TESTS_TRUE@TESTS = \
+@ENABLE_TESTS_TRUE@   tests/pngtest-all\
+@ENABLE_TESTS_TRUE@   tests/pngvalid-gamma-16-to-8 tests/pngvalid-gamma-alpha-mode\
+@ENABLE_TESTS_TRUE@   tests/pngvalid-gamma-background tests/pngvalid-gamma-expand16-alpha-mode\
+@ENABLE_TESTS_TRUE@   tests/pngvalid-gamma-expand16-background\
+@ENABLE_TESTS_TRUE@   tests/pngvalid-gamma-expand16-transform tests/pngvalid-gamma-sbit\
+@ENABLE_TESTS_TRUE@   tests/pngvalid-gamma-threshold tests/pngvalid-gamma-transform\
+@ENABLE_TESTS_TRUE@   tests/pngvalid-progressive-size\
+@ENABLE_TESTS_TRUE@   tests/pngvalid-progressive-interlace-standard\
+@ENABLE_TESTS_TRUE@   tests/pngvalid-transform\
+@ENABLE_TESTS_TRUE@   tests/pngvalid-progressive-standard tests/pngvalid-standard\
+@ENABLE_TESTS_TRUE@   tests/pngstest-1.8 tests/pngstest-1.8-alpha tests/pngstest-linear\
+@ENABLE_TESTS_TRUE@   tests/pngstest-linear-alpha tests/pngstest-none tests/pngstest-none-alpha\
+@ENABLE_TESTS_TRUE@   tests/pngstest-sRGB tests/pngstest-sRGB-alpha tests/pngunknown-IDAT\
+@ENABLE_TESTS_TRUE@   tests/pngunknown-discard tests/pngunknown-if-safe tests/pngunknown-sAPI\
+@ENABLE_TESTS_TRUE@   tests/pngunknown-sTER tests/pngunknown-save tests/pngunknown-vpAg\
+@ENABLE_TESTS_TRUE@   tests/pngimage-quick tests/pngimage-full
+
+
+# man pages
+dist_man_MANS = libpng.3 libpngpf.3 png.5
+EXTRA_SCRIPTS = libpng-config libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
+bin_SCRIPTS = @binconfigs@
+
+# rules to build libpng, only build the old library on request
+lib_LTLIBRARIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+# EXTRA_LTLIBRARIES= libpng.la
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c \
+	pngget.c pngmem.c pngpread.c pngread.c pngrio.c pngrtran.c \
+	pngrutil.c pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c \
+	pngwutil.c png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h \
+	pngstruct.h pngusr.dfa $(am__append_2) $(am__append_3) \
+	$(am__append_4) $(am__append_5) $(am__append_6) \
+	$(am__append_7)
+@PNG_LOONGARCH_LSX_TRUE@noinst_LTLIBRARIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+@PNG_LOONGARCH_LSX_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_SOURCES = loongarch/loongarch_lsx_init.c\
+@PNG_LOONGARCH_LSX_TRUE@	loongarch/filter_lsx_intrinsics.c
+
+@PNG_LOONGARCH_LSX_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_CFLAGS = -mlsx
+@PNG_LOONGARCH_LSX_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+# libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la
+nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined \
+	-export-dynamic -version-number \
+	@PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0 \
+	$(am__append_8) $(am__append_9) $(am__append_10)
+@HAVE_LD_VERSION_SCRIPT_FALSE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES =  \
+@HAVE_LD_VERSION_SCRIPT_FALSE@	libpng.sym $(am__append_11)
+@HAVE_LD_VERSION_SCRIPT_TRUE@libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES =  \
+@HAVE_LD_VERSION_SCRIPT_TRUE@	libpng.vers $(am__append_11)
+pkginclude_HEADERS = png.h pngconf.h
+nodist_pkginclude_HEADERS = pnglibconf.h
+pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc
+
+# Extra source distribution files, '${srcdir}' is used below to stop build files
+# from those directories being included.  This only works if the configure is
+# not done in the source directory!
+EXTRA_DIST = \
+	ANNOUNCE AUTHORS CHANGES INSTALL LICENSE README TODO TRADEMARK \
+	pngtest.png pngbar.png pngnow.png pngbar.jpg autogen.sh \
+	${srcdir}/ci ${srcdir}/contrib ${srcdir}/projects ${srcdir}/scripts \
+	$(TESTS) $(XFAIL_TESTS) tests/pngstest \
+	CMakeLists.txt example.c libpng-manual.txt
+
+SCRIPT_CLEANFILES = scripts/*.out scripts/*.chk
+CLEANFILES = *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
+	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
+	check.new pnglibconf.h pngprefix.h symbols.new pngtest-log.txt \
+	pnglibconf.out pnglibconf.c pnglibconf.pre pnglibconf.dfn \
+	$(SCRIPT_CLEANFILES)
+
+MAINTAINERCLEANFILES = Makefile.in aclocal.m4 config.guess config.h.in \
+config.sub configure depcomp install-sh ltmain.sh missing
+
+AM_CFLAGS = ${PNG_COPTS}
+SUFFIXES = .chk .out
+
+# We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
+# be built with PNG_USE_READ_MACROS; this prevents the read macros from
+# interfering with the symbol file format.
+SYMBOL_CFLAGS = -DPNGLIB_LIBNAME='PNG@PNGLIB_MAJOR@@PNGLIB_MINOR@_0' \
+	-DPNGLIB_VERSION='@PNGLIB_VERSION@' \
+	-DSYMBOL_PREFIX='$(SYMBOL_PREFIX)' -DPNG_NO_USE_READ_MACROS \
+	-DPNG_BUILDING_SYMBOL_TABLE $(am__append_12)
+
+# EXT_LIST is a list of the possibly library directory extensions, this exists
+# because we can't find a good way of discovering the file extensions that are
+# actually installed on a given system, so instead we check for every extension
+# we have seen.
+EXT_LIST = a dll.a so so.@PNGLIB_MAJOR@@PNGLIB_MINOR@.@PNGLIB_RELEASE@ la sl dylib
+all: $(BUILT_SOURCES) config.h
+	$(MAKE) $(AM_MAKEFLAGS) all-am
+
+.SUFFIXES:
+.SUFFIXES: .chk .out .S .c .lo .log .o .obj .test .test$(EXEEXT) .trs
+am--refresh: Makefile
+	@:
+$(srcdir)/Makefile.in: @MAINTAINER_MODE_TRUE@ $(srcdir)/Makefile.am  $(am__configure_deps)
+	@for dep in $?; do \
+	  case '$(am__configure_deps)' in \
+	    *$$dep*) \
+	      echo ' cd $(srcdir) && $(AUTOMAKE) --foreign'; \
+	      $(am__cd) $(srcdir) && $(AUTOMAKE) --foreign \
+		&& exit 0; \
+	      exit 1;; \
+	  esac; \
+	done; \
+	echo ' cd $(top_srcdir) && $(AUTOMAKE) --foreign Makefile'; \
+	$(am__cd) $(top_srcdir) && \
+	  $(AUTOMAKE) --foreign Makefile
+Makefile: $(srcdir)/Makefile.in $(top_builddir)/config.status
+	@case '$?' in \
+	  *config.status*) \
+	    echo ' $(SHELL) ./config.status'; \
+	    $(SHELL) ./config.status;; \
+	  *) \
+	    echo ' cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__maybe_remake_depfiles)'; \
+	    cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__maybe_remake_depfiles);; \
+	esac;
+
+$(top_builddir)/config.status: $(top_srcdir)/configure $(CONFIG_STATUS_DEPENDENCIES)
+	$(SHELL) ./config.status --recheck
+
+$(top_srcdir)/configure: @MAINTAINER_MODE_TRUE@ $(am__configure_deps)
+	$(am__cd) $(srcdir) && $(AUTOCONF)
+$(ACLOCAL_M4): @MAINTAINER_MODE_TRUE@ $(am__aclocal_m4_deps)
+	$(am__cd) $(srcdir) && $(ACLOCAL) $(ACLOCAL_AMFLAGS)
+$(am__aclocal_m4_deps):
+
+config.h: stamp-h1
+	@test -f $@ || rm -f stamp-h1
+	@test -f $@ || $(MAKE) $(AM_MAKEFLAGS) stamp-h1
+
+stamp-h1: $(srcdir)/config.h.in $(top_builddir)/config.status
+	@rm -f stamp-h1
+	cd $(top_builddir) && $(SHELL) ./config.status config.h
+$(srcdir)/config.h.in: @MAINTAINER_MODE_TRUE@ $(am__configure_deps) 
+	($(am__cd) $(top_srcdir) && $(AUTOHEADER))
+	rm -f stamp-h1
+	touch $@
+
+distclean-hdr:
+	-rm -f config.h stamp-h1
+libpng.pc: $(top_builddir)/config.status $(srcdir)/libpng.pc.in
+	cd $(top_builddir) && $(SHELL) ./config.status $@
+libpng-config: $(top_builddir)/config.status $(srcdir)/libpng-config.in
+	cd $(top_builddir) && $(SHELL) ./config.status $@
+install-binPROGRAMS: $(bin_PROGRAMS)
+	@$(NORMAL_INSTALL)
+	@list='$(bin_PROGRAMS)'; test -n "$(bindir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(bindir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(bindir)" || exit 1; \
+	fi; \
+	for p in $$list; do echo "$$p $$p"; done | \
+	sed 's/$(EXEEXT)$$//' | \
+	while read p p1; do if test -f $$p \
+	 || test -f $$p1 \
+	  ; then echo "$$p"; echo "$$p"; else :; fi; \
+	done | \
+	sed -e 'p;s,.*/,,;n;h' \
+	    -e 's|.*|.|' \
+	    -e 'p;x;s,.*/,,;s/$(EXEEXT)$$//;$(transform);s/$$/$(EXEEXT)/' | \
+	sed 'N;N;N;s,\n, ,g' | \
+	$(AWK) 'BEGIN { files["."] = ""; dirs["."] = 1 } \
+	  { d=$$3; if (dirs[d] != 1) { print "d", d; dirs[d] = 1 } \
+	    if ($$2 == $$4) files[d] = files[d] " " $$1; \
+	    else { print "f", $$3 "/" $$4, $$1; } } \
+	  END { for (d in files) print "f", d, files[d] }' | \
+	while read type dir files; do \
+	    if test "$$dir" = .; then dir=; else dir=/$$dir; fi; \
+	    test -z "$$files" || { \
+	    echo " $(INSTALL_PROGRAM_ENV) $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=install $(INSTALL_PROGRAM) $$files '$(DESTDIR)$(bindir)$$dir'"; \
+	    $(INSTALL_PROGRAM_ENV) $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=install $(INSTALL_PROGRAM) $$files "$(DESTDIR)$(bindir)$$dir" || exit $$?; \
+	    } \
+	; done
+
+uninstall-binPROGRAMS:
+	@$(NORMAL_UNINSTALL)
+	@list='$(bin_PROGRAMS)'; test -n "$(bindir)" || list=; \
+	files=`for p in $$list; do echo "$$p"; done | \
+	  sed -e 'h;s,^.*/,,;s/$(EXEEXT)$$//;$(transform)' \
+	      -e 's/$$/$(EXEEXT)/' \
+	`; \
+	test -n "$$list" || exit 0; \
+	echo " ( cd '$(DESTDIR)$(bindir)' && rm -f" $$files ")"; \
+	cd "$(DESTDIR)$(bindir)" && rm -f $$files
+
+clean-binPROGRAMS:
+	@list='$(bin_PROGRAMS)'; test -n "$$list" || exit 0; \
+	echo " rm -f" $$list; \
+	rm -f $$list || exit $$?; \
+	test -n "$(EXEEXT)" || exit 0; \
+	list=`for p in $$list; do echo "$$p"; done | sed 's/$(EXEEXT)$$//'`; \
+	echo " rm -f" $$list; \
+	rm -f $$list
+
+clean-checkPROGRAMS:
+	@list='$(check_PROGRAMS)'; test -n "$$list" || exit 0; \
+	echo " rm -f" $$list; \
+	rm -f $$list || exit $$?; \
+	test -n "$(EXEEXT)" || exit 0; \
+	list=`for p in $$list; do echo "$$p"; done | sed 's/$(EXEEXT)$$//'`; \
+	echo " rm -f" $$list; \
+	rm -f $$list
+
+install-libLTLIBRARIES: $(lib_LTLIBRARIES)
+	@$(NORMAL_INSTALL)
+	@list='$(lib_LTLIBRARIES)'; test -n "$(libdir)" || list=; \
+	list2=; for p in $$list; do \
+	  if test -f $$p; then \
+	    list2="$$list2 $$p"; \
+	  else :; fi; \
+	done; \
+	test -z "$$list2" || { \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(libdir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(libdir)" || exit 1; \
+	  echo " $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=install $(INSTALL) $(INSTALL_STRIP_FLAG) $$list2 '$(DESTDIR)$(libdir)'"; \
+	  $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=install $(INSTALL) $(INSTALL_STRIP_FLAG) $$list2 "$(DESTDIR)$(libdir)"; \
+	}
+
+uninstall-libLTLIBRARIES:
+	@$(NORMAL_UNINSTALL)
+	@list='$(lib_LTLIBRARIES)'; test -n "$(libdir)" || list=; \
+	for p in $$list; do \
+	  $(am__strip_dir) \
+	  echo " $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=uninstall rm -f '$(DESTDIR)$(libdir)/$$f'"; \
+	  $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=uninstall rm -f "$(DESTDIR)$(libdir)/$$f"; \
+	done
+
+clean-libLTLIBRARIES:
+	-test -z "$(lib_LTLIBRARIES)" || rm -f $(lib_LTLIBRARIES)
+	@list='$(lib_LTLIBRARIES)'; \
+	locs=`for p in $$list; do echo $$p; done | \
+	      sed 's|^[^/]*$$|.|; s|/[^/]*$$||; s|$$|/so_locations|' | \
+	      sort -u`; \
+	test -z "$$locs" || { \
+	  echo rm -f $${locs}; \
+	  rm -f $${locs}; \
+	}
+
+clean-noinstLTLIBRARIES:
+	-test -z "$(noinst_LTLIBRARIES)" || rm -f $(noinst_LTLIBRARIES)
+	@list='$(noinst_LTLIBRARIES)'; \
+	locs=`for p in $$list; do echo $$p; done | \
+	      sed 's|^[^/]*$$|.|; s|/[^/]*$$||; s|$$|/so_locations|' | \
+	      sort -u`; \
+	test -z "$$locs" || { \
+	  echo rm -f $${locs}; \
+	  rm -f $${locs}; \
+	}
+arm/$(am__dirstamp):
+	@$(MKDIR_P) arm
+	@: > arm/$(am__dirstamp)
+arm/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) arm/$(DEPDIR)
+	@: > arm/$(DEPDIR)/$(am__dirstamp)
+arm/arm_init.lo: arm/$(am__dirstamp) arm/$(DEPDIR)/$(am__dirstamp)
+arm/filter_neon.lo: arm/$(am__dirstamp) arm/$(DEPDIR)/$(am__dirstamp)
+arm/filter_neon_intrinsics.lo: arm/$(am__dirstamp) \
+	arm/$(DEPDIR)/$(am__dirstamp)
+arm/palette_neon_intrinsics.lo: arm/$(am__dirstamp) \
+	arm/$(DEPDIR)/$(am__dirstamp)
+mips/$(am__dirstamp):
+	@$(MKDIR_P) mips
+	@: > mips/$(am__dirstamp)
+mips/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) mips/$(DEPDIR)
+	@: > mips/$(DEPDIR)/$(am__dirstamp)
+mips/mips_init.lo: mips/$(am__dirstamp) mips/$(DEPDIR)/$(am__dirstamp)
+mips/filter_msa_intrinsics.lo: mips/$(am__dirstamp) \
+	mips/$(DEPDIR)/$(am__dirstamp)
+mips/filter_mmi_inline_assembly.lo: mips/$(am__dirstamp) \
+	mips/$(DEPDIR)/$(am__dirstamp)
+intel/$(am__dirstamp):
+	@$(MKDIR_P) intel
+	@: > intel/$(am__dirstamp)
+intel/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) intel/$(DEPDIR)
+	@: > intel/$(DEPDIR)/$(am__dirstamp)
+intel/intel_init.lo: intel/$(am__dirstamp) \
+	intel/$(DEPDIR)/$(am__dirstamp)
+intel/filter_sse2_intrinsics.lo: intel/$(am__dirstamp) \
+	intel/$(DEPDIR)/$(am__dirstamp)
+powerpc/$(am__dirstamp):
+	@$(MKDIR_P) powerpc
+	@: > powerpc/$(am__dirstamp)
+powerpc/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) powerpc/$(DEPDIR)
+	@: > powerpc/$(DEPDIR)/$(am__dirstamp)
+powerpc/powerpc_init.lo: powerpc/$(am__dirstamp) \
+	powerpc/$(DEPDIR)/$(am__dirstamp)
+powerpc/filter_vsx_intrinsics.lo: powerpc/$(am__dirstamp) \
+	powerpc/$(DEPDIR)/$(am__dirstamp)
+
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la: $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES) $(EXTRA_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES) 
+	$(AM_V_CCLD)$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LINK) -rpath $(libdir) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD) $(LIBS)
+loongarch/$(am__dirstamp):
+	@$(MKDIR_P) loongarch
+	@: > loongarch/$(am__dirstamp)
+loongarch/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) loongarch/$(DEPDIR)
+	@: > loongarch/$(DEPDIR)/$(am__dirstamp)
+loongarch/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la-loongarch_lsx_init.lo:  \
+	loongarch/$(am__dirstamp) loongarch/$(DEPDIR)/$(am__dirstamp)
+loongarch/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la-filter_lsx_intrinsics.lo:  \
+	loongarch/$(am__dirstamp) loongarch/$(DEPDIR)/$(am__dirstamp)
+
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx.la: $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_DEPENDENCIES) $(EXTRA_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_DEPENDENCIES) 
+	$(AM_V_CCLD)$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_LINK) $(am_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_rpath) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la_LIBADD) $(LIBS)
+contrib/tools/$(am__dirstamp):
+	@$(MKDIR_P) contrib/tools
+	@: > contrib/tools/$(am__dirstamp)
+contrib/tools/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) contrib/tools/$(DEPDIR)
+	@: > contrib/tools/$(DEPDIR)/$(am__dirstamp)
+contrib/tools/png-fix-itxt.$(OBJEXT): contrib/tools/$(am__dirstamp) \
+	contrib/tools/$(DEPDIR)/$(am__dirstamp)
+
+png-fix-itxt$(EXEEXT): $(png_fix_itxt_OBJECTS) $(png_fix_itxt_DEPENDENCIES) $(EXTRA_png_fix_itxt_DEPENDENCIES) 
+	@rm -f png-fix-itxt$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(png_fix_itxt_OBJECTS) $(png_fix_itxt_LDADD) $(LIBS)
+contrib/tools/pngcp.$(OBJEXT): contrib/tools/$(am__dirstamp) \
+	contrib/tools/$(DEPDIR)/$(am__dirstamp)
+
+pngcp$(EXEEXT): $(pngcp_OBJECTS) $(pngcp_DEPENDENCIES) $(EXTRA_pngcp_DEPENDENCIES) 
+	@rm -f pngcp$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngcp_OBJECTS) $(pngcp_LDADD) $(LIBS)
+contrib/tools/pngfix.$(OBJEXT): contrib/tools/$(am__dirstamp) \
+	contrib/tools/$(DEPDIR)/$(am__dirstamp)
+
+pngfix$(EXEEXT): $(pngfix_OBJECTS) $(pngfix_DEPENDENCIES) $(EXTRA_pngfix_DEPENDENCIES) 
+	@rm -f pngfix$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngfix_OBJECTS) $(pngfix_LDADD) $(LIBS)
+contrib/libtests/$(am__dirstamp):
+	@$(MKDIR_P) contrib/libtests
+	@: > contrib/libtests/$(am__dirstamp)
+contrib/libtests/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) contrib/libtests/$(DEPDIR)
+	@: > contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+contrib/libtests/pngimage.$(OBJEXT): contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+pngimage$(EXEEXT): $(pngimage_OBJECTS) $(pngimage_DEPENDENCIES) $(EXTRA_pngimage_DEPENDENCIES) 
+	@rm -f pngimage$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngimage_OBJECTS) $(pngimage_LDADD) $(LIBS)
+contrib/libtests/pngstest.$(OBJEXT): contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+pngstest$(EXEEXT): $(pngstest_OBJECTS) $(pngstest_DEPENDENCIES) $(EXTRA_pngstest_DEPENDENCIES) 
+	@rm -f pngstest$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngstest_OBJECTS) $(pngstest_LDADD) $(LIBS)
+
+pngtest$(EXEEXT): $(pngtest_OBJECTS) $(pngtest_DEPENDENCIES) $(EXTRA_pngtest_DEPENDENCIES) 
+	@rm -f pngtest$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngtest_OBJECTS) $(pngtest_LDADD) $(LIBS)
+contrib/libtests/pngunknown.$(OBJEXT):  \
+	contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+pngunknown$(EXEEXT): $(pngunknown_OBJECTS) $(pngunknown_DEPENDENCIES) $(EXTRA_pngunknown_DEPENDENCIES) 
+	@rm -f pngunknown$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngunknown_OBJECTS) $(pngunknown_LDADD) $(LIBS)
+contrib/libtests/pngvalid.$(OBJEXT): contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+pngvalid$(EXEEXT): $(pngvalid_OBJECTS) $(pngvalid_DEPENDENCIES) $(EXTRA_pngvalid_DEPENDENCIES) 
+	@rm -f pngvalid$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(pngvalid_OBJECTS) $(pngvalid_LDADD) $(LIBS)
+contrib/libtests/timepng.$(OBJEXT): contrib/libtests/$(am__dirstamp) \
+	contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+
+timepng$(EXEEXT): $(timepng_OBJECTS) $(timepng_DEPENDENCIES) $(EXTRA_timepng_DEPENDENCIES) 
+	@rm -f timepng$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(timepng_OBJECTS) $(timepng_LDADD) $(LIBS)
+install-binSCRIPTS: $(bin_SCRIPTS)
+	@$(NORMAL_INSTALL)
+	@list='$(bin_SCRIPTS)'; test -n "$(bindir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(bindir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(bindir)" || exit 1; \
+	fi; \
+	for p in $$list; do \
+	  if test -f "$$p"; then d=; else d="$(srcdir)/"; fi; \
+	  if test -f "$$d$$p"; then echo "$$d$$p"; echo "$$p"; else :; fi; \
+	done | \
+	sed -e 'p;s,.*/,,;n' \
+	    -e 'h;s|.*|.|' \
+	    -e 'p;x;s,.*/,,;$(transform)' | sed 'N;N;N;s,\n, ,g' | \
+	$(AWK) 'BEGIN { files["."] = ""; dirs["."] = 1; } \
+	  { d=$$3; if (dirs[d] != 1) { print "d", d; dirs[d] = 1 } \
+	    if ($$2 == $$4) { files[d] = files[d] " " $$1; \
+	      if (++n[d] == $(am__install_max)) { \
+		print "f", d, files[d]; n[d] = 0; files[d] = "" } } \
+	    else { print "f", d "/" $$4, $$1 } } \
+	  END { for (d in files) print "f", d, files[d] }' | \
+	while read type dir files; do \
+	     if test "$$dir" = .; then dir=; else dir=/$$dir; fi; \
+	     test -z "$$files" || { \
+	       echo " $(INSTALL_SCRIPT) $$files '$(DESTDIR)$(bindir)$$dir'"; \
+	       $(INSTALL_SCRIPT) $$files "$(DESTDIR)$(bindir)$$dir" || exit $$?; \
+	     } \
+	; done
+
+uninstall-binSCRIPTS:
+	@$(NORMAL_UNINSTALL)
+	@list='$(bin_SCRIPTS)'; test -n "$(bindir)" || exit 0; \
+	files=`for p in $$list; do echo "$$p"; done | \
+	       sed -e 's,.*/,,;$(transform)'`; \
+	dir='$(DESTDIR)$(bindir)'; $(am__uninstall_files_from_dir)
+
+mostlyclean-compile:
+	-rm -f *.$(OBJEXT)
+	-rm -f arm/*.$(OBJEXT)
+	-rm -f arm/*.lo
+	-rm -f contrib/libtests/*.$(OBJEXT)
+	-rm -f contrib/tools/*.$(OBJEXT)
+	-rm -f intel/*.$(OBJEXT)
+	-rm -f intel/*.lo
+	-rm -f loongarch/*.$(OBJEXT)
+	-rm -f loongarch/*.lo
+	-rm -f mips/*.$(OBJEXT)
+	-rm -f mips/*.lo
+	-rm -f powerpc/*.$(OBJEXT)
+	-rm -f powerpc/*.lo
+
+distclean-compile:
+	-rm -f *.tab.c
+
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/png.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngerror.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngget.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngmem.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngpread.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngread.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngrio.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngrtran.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngrutil.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngset.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngtest.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pngtrans.Plo@am__quote@ # am--include-marker
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+	for i in $$list; do \
+	  if test -f "$$i"; then \
+	    echo "$(subdir)/$$i"; \
+	  else \
+	    echo "$$sdir/$$i"; \
+	  fi; \
+	done >> $(top_builddir)/cscope.files
+
+distclean-tags:
+	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
+	-rm -f cscope.out cscope.in.out cscope.po.out cscope.files
+
+# Recover from deleted '.trs' file; this should ensure that
+# "rm -f foo.log; make foo.trs" re-run 'foo.test', and re-create
+# both 'foo.log' and 'foo.trs'.  Break the recipe in two subshells
+# to avoid problems with "make -n".
+.log.trs:
+	rm -f $< $@
+	$(MAKE) $(AM_MAKEFLAGS) $<
+
+# Leading 'am--fnord' is there to ensure the list of targets does not
+# expand to empty, as could happen e.g. with make check TESTS=''.
+am--fnord $(TEST_LOGS) $(TEST_LOGS:.log=.trs): $(am__force_recheck)
+am--force-recheck:
+	@:
+
+$(TEST_SUITE_LOG): $(TEST_LOGS)
+	@$(am__set_TESTS_bases); \
+	am__f_ok () { test -f "$$1" && test -r "$$1"; }; \
+	redo_bases=`for i in $$bases; do \
+	              am__f_ok $$i.trs && am__f_ok $$i.log || echo $$i; \
+	            done`; \
+	if test -n "$$redo_bases"; then \
+	  redo_logs=`for i in $$redo_bases; do echo $$i.log; done`; \
+	  redo_results=`for i in $$redo_bases; do echo $$i.trs; done`; \
+	  if $(am__make_dryrun); then :; else \
+	    rm -f $$redo_logs && rm -f $$redo_results || exit 1; \
+	  fi; \
+	fi; \
+	if test -n "$$am__remaking_logs"; then \
+	  echo "fatal: making $(TEST_SUITE_LOG): possible infinite" \
+	       "recursion detected" >&2; \
+	elif test -n "$$redo_logs"; then \
+	  am__remaking_logs=yes $(MAKE) $(AM_MAKEFLAGS) $$redo_logs; \
+	fi; \
+	if $(am__make_dryrun); then :; else \
+	  st=0;  \
+	  errmsg="fatal: making $(TEST_SUITE_LOG): failed to create"; \
+	  for i in $$redo_bases; do \
+	    test -f $$i.trs && test -r $$i.trs \
+	      || { echo "$$errmsg $$i.trs" >&2; st=1; }; \
+	    test -f $$i.log && test -r $$i.log \
+	      || { echo "$$errmsg $$i.log" >&2; st=1; }; \
+	  done; \
+	  test $$st -eq 0 || exit 1; \
+	fi
+	@$(am__sh_e_setup); $(am__tty_colors); $(am__set_TESTS_bases); \
+	ws='[ 	]'; \
+	results=`for b in $$bases; do echo $$b.trs; done`; \
+	test -n "$$results" || results=/dev/null; \
+	all=`  grep "^$$ws*:test-result:"           $$results | wc -l`; \
+	pass=` grep "^$$ws*:test-result:$$ws*PASS"  $$results | wc -l`; \
+	fail=` grep "^$$ws*:test-result:$$ws*FAIL"  $$results | wc -l`; \
+	skip=` grep "^$$ws*:test-result:$$ws*SKIP"  $$results | wc -l`; \
+	xfail=`grep "^$$ws*:test-result:$$ws*XFAIL" $$results | wc -l`; \
+	xpass=`grep "^$$ws*:test-result:$$ws*XPASS" $$results | wc -l`; \
+	error=`grep "^$$ws*:test-result:$$ws*ERROR" $$results | wc -l`; \
+	if test `expr $$fail + $$xpass + $$error` -eq 0; then \
+	  success=true; \
+	else \
+	  success=false; \
+	fi; \
+	br='==================='; br=$$br$$br$$br$$br; \
+	result_count () \
+	{ \
+	    if test x"$$1" = x"--maybe-color"; then \
+	      maybe_colorize=yes; \
+	    elif test x"$$1" = x"--no-color"; then \
+	      maybe_colorize=no; \
+	    else \
+	      echo "$@: invalid 'result_count' usage" >&2; exit 4; \
+	    fi; \
+	    shift; \
+	    desc=$$1 count=$$2; \
+	    if test $$maybe_colorize = yes && test $$count -gt 0; then \
+	      color_start=$$3 color_end=$$std; \
+	    else \
+	      color_start= color_end=; \
+	    fi; \
+	    echo "$${color_start}# $$desc $$count$${color_end}"; \
+	}; \
+	create_testsuite_report () \
+	{ \
+	  result_count $$1 "TOTAL:" $$all   "$$brg"; \
+	  result_count $$1 "PASS: " $$pass  "$$grn"; \
+	  result_count $$1 "SKIP: " $$skip  "$$blu"; \
+	  result_count $$1 "XFAIL:" $$xfail "$$lgn"; \
+	  result_count $$1 "FAIL: " $$fail  "$$red"; \
+	  result_count $$1 "XPASS:" $$xpass "$$red"; \
+	  result_count $$1 "ERROR:" $$error "$$mgn"; \
+	}; \
+	{								\
+	  echo "$(PACKAGE_STRING): $(subdir)/$(TEST_SUITE_LOG)" |	\
+	    $(am__rst_title);						\
+	  create_testsuite_report --no-color;				\
+	  echo;								\
+	  echo ".. contents:: :depth: 2";				\
+	  echo;								\
+	  for b in $$bases; do echo $$b; done				\
+	    | $(am__create_global_log);					\
+	} >$(TEST_SUITE_LOG).tmp || exit 1;				\
+	mv $(TEST_SUITE_LOG).tmp $(TEST_SUITE_LOG);			\
+	if $$success; then						\
+	  col="$$grn";							\
+	 else								\
+	  col="$$red";							\
+	  test x"$$VERBOSE" = x || cat $(TEST_SUITE_LOG);		\
+	fi;								\
+	echo "$${col}$$br$${std}"; 					\
+	echo "$${col}Testsuite summary"$(AM_TESTSUITE_SUMMARY_HEADER)"$${std}";	\
+	echo "$${col}$$br$${std}"; 					\
+	create_testsuite_report --maybe-color;				\
+	echo "$$col$$br$$std";						\
+	if $$success; then :; else					\
+	  echo "$${col}See $(subdir)/$(TEST_SUITE_LOG)$${std}";		\
+	  if test -n "$(PACKAGE_BUGREPORT)"; then			\
+	    echo "$${col}Please report to $(PACKAGE_BUGREPORT)$${std}";	\
+	  fi;								\
+	  echo "$$col$$br$$std";					\
+	fi;								\
+	$$success || exit 1
+
+check-TESTS: $(check_PROGRAMS)
+	@list='$(RECHECK_LOGS)';           test -z "$$list" || rm -f $$list
+	@list='$(RECHECK_LOGS:.log=.trs)'; test -z "$$list" || rm -f $$list
+	@test -z "$(TEST_SUITE_LOG)" || rm -f $(TEST_SUITE_LOG)
+	@set +e; $(am__set_TESTS_bases); \
+	log_list=`for i in $$bases; do echo $$i.log; done`; \
+	trs_list=`for i in $$bases; do echo $$i.trs; done`; \
+	log_list=`echo $$log_list`; trs_list=`echo $$trs_list`; \
+	$(MAKE) $(AM_MAKEFLAGS) $(TEST_SUITE_LOG) TEST_LOGS="$$log_list"; \
+	exit $$?;
+recheck: all $(check_PROGRAMS)
+	@test -z "$(TEST_SUITE_LOG)" || rm -f $(TEST_SUITE_LOG)
+	@set +e; $(am__set_TESTS_bases); \
+	bases=`for i in $$bases; do echo $$i; done \
+	         | $(am__list_recheck_tests)` || exit 1; \
+	log_list=`for i in $$bases; do echo $$i.log; done`; \
+	log_list=`echo $$log_list`; \
+	$(MAKE) $(AM_MAKEFLAGS) $(TEST_SUITE_LOG) \
+	        am__force_recheck=am--force-recheck \
+	        TEST_LOGS="$$log_list"; \
+	exit $$?
+tests/pngtest-all.log: tests/pngtest-all
+	@p='tests/pngtest-all'; \
+	b='tests/pngtest-all'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-16-to-8.log: tests/pngvalid-gamma-16-to-8
+	@p='tests/pngvalid-gamma-16-to-8'; \
+	b='tests/pngvalid-gamma-16-to-8'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-alpha-mode.log: tests/pngvalid-gamma-alpha-mode
+	@p='tests/pngvalid-gamma-alpha-mode'; \
+	b='tests/pngvalid-gamma-alpha-mode'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-background.log: tests/pngvalid-gamma-background
+	@p='tests/pngvalid-gamma-background'; \
+	b='tests/pngvalid-gamma-background'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-expand16-alpha-mode.log: tests/pngvalid-gamma-expand16-alpha-mode
+	@p='tests/pngvalid-gamma-expand16-alpha-mode'; \
+	b='tests/pngvalid-gamma-expand16-alpha-mode'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-expand16-background.log: tests/pngvalid-gamma-expand16-background
+	@p='tests/pngvalid-gamma-expand16-background'; \
+	b='tests/pngvalid-gamma-expand16-background'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-expand16-transform.log: tests/pngvalid-gamma-expand16-transform
+	@p='tests/pngvalid-gamma-expand16-transform'; \
+	b='tests/pngvalid-gamma-expand16-transform'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-sbit.log: tests/pngvalid-gamma-sbit
+	@p='tests/pngvalid-gamma-sbit'; \
+	b='tests/pngvalid-gamma-sbit'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-threshold.log: tests/pngvalid-gamma-threshold
+	@p='tests/pngvalid-gamma-threshold'; \
+	b='tests/pngvalid-gamma-threshold'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-gamma-transform.log: tests/pngvalid-gamma-transform
+	@p='tests/pngvalid-gamma-transform'; \
+	b='tests/pngvalid-gamma-transform'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-progressive-size.log: tests/pngvalid-progressive-size
+	@p='tests/pngvalid-progressive-size'; \
+	b='tests/pngvalid-progressive-size'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-progressive-interlace-standard.log: tests/pngvalid-progressive-interlace-standard
+	@p='tests/pngvalid-progressive-interlace-standard'; \
+	b='tests/pngvalid-progressive-interlace-standard'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-transform.log: tests/pngvalid-transform
+	@p='tests/pngvalid-transform'; \
+	b='tests/pngvalid-transform'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-progressive-standard.log: tests/pngvalid-progressive-standard
+	@p='tests/pngvalid-progressive-standard'; \
+	b='tests/pngvalid-progressive-standard'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngvalid-standard.log: tests/pngvalid-standard
+	@p='tests/pngvalid-standard'; \
+	b='tests/pngvalid-standard'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-1.8.log: tests/pngstest-1.8
+	@p='tests/pngstest-1.8'; \
+	b='tests/pngstest-1.8'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-1.8-alpha.log: tests/pngstest-1.8-alpha
+	@p='tests/pngstest-1.8-alpha'; \
+	b='tests/pngstest-1.8-alpha'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-linear.log: tests/pngstest-linear
+	@p='tests/pngstest-linear'; \
+	b='tests/pngstest-linear'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-linear-alpha.log: tests/pngstest-linear-alpha
+	@p='tests/pngstest-linear-alpha'; \
+	b='tests/pngstest-linear-alpha'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-none.log: tests/pngstest-none
+	@p='tests/pngstest-none'; \
+	b='tests/pngstest-none'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-none-alpha.log: tests/pngstest-none-alpha
+	@p='tests/pngstest-none-alpha'; \
+	b='tests/pngstest-none-alpha'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-sRGB.log: tests/pngstest-sRGB
+	@p='tests/pngstest-sRGB'; \
+	b='tests/pngstest-sRGB'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngstest-sRGB-alpha.log: tests/pngstest-sRGB-alpha
+	@p='tests/pngstest-sRGB-alpha'; \
+	b='tests/pngstest-sRGB-alpha'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-IDAT.log: tests/pngunknown-IDAT
+	@p='tests/pngunknown-IDAT'; \
+	b='tests/pngunknown-IDAT'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-discard.log: tests/pngunknown-discard
+	@p='tests/pngunknown-discard'; \
+	b='tests/pngunknown-discard'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-if-safe.log: tests/pngunknown-if-safe
+	@p='tests/pngunknown-if-safe'; \
+	b='tests/pngunknown-if-safe'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-sAPI.log: tests/pngunknown-sAPI
+	@p='tests/pngunknown-sAPI'; \
+	b='tests/pngunknown-sAPI'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-sTER.log: tests/pngunknown-sTER
+	@p='tests/pngunknown-sTER'; \
+	b='tests/pngunknown-sTER'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-save.log: tests/pngunknown-save
+	@p='tests/pngunknown-save'; \
+	b='tests/pngunknown-save'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngunknown-vpAg.log: tests/pngunknown-vpAg
+	@p='tests/pngunknown-vpAg'; \
+	b='tests/pngunknown-vpAg'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngimage-quick.log: tests/pngimage-quick
+	@p='tests/pngimage-quick'; \
+	b='tests/pngimage-quick'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+tests/pngimage-full.log: tests/pngimage-full
+	@p='tests/pngimage-full'; \
+	b='tests/pngimage-full'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+.test.log:
+	@p='$<'; \
+	$(am__set_b); \
+	$(am__check_pre) $(TEST_LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_TEST_LOG_DRIVER_FLAGS) $(TEST_LOG_DRIVER_FLAGS) -- $(TEST_LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
+@am__EXEEXT_TRUE@.test$(EXEEXT).log:
+@am__EXEEXT_TRUE@	@p='$<'; \
+@am__EXEEXT_TRUE@	$(am__set_b); \
+@am__EXEEXT_TRUE@	$(am__check_pre) $(TEST_LOG_DRIVER) --test-name "$$f" \
+@am__EXEEXT_TRUE@	--log-file $$b.log --trs-file $$b.trs \
+@am__EXEEXT_TRUE@	$(am__common_driver_flags) $(AM_TEST_LOG_DRIVER_FLAGS) $(TEST_LOG_DRIVER_FLAGS) -- $(TEST_LOG_COMPILE) \
+@am__EXEEXT_TRUE@	"$$tst" $(AM_TESTS_FD_REDIRECT)
+distdir: $(BUILT_SOURCES)
+	$(MAKE) $(AM_MAKEFLAGS) distdir-am
+
+distdir-am: $(DISTFILES)
+	$(am__remove_distdir)
+	test -d "$(distdir)" || mkdir "$(distdir)"
+	@srcdirstrip=`echo "$(srcdir)" | sed 's/[].[^$$\\*]/\\\\&/g'`; \
+	topsrcdirstrip=`echo "$(top_srcdir)" | sed 's/[].[^$$\\*]/\\\\&/g'`; \
+	list='$(DISTFILES)'; \
+	  dist_files=`for file in $$list; do echo $$file; done | \
+	  sed -e "s|^$$srcdirstrip/||;t" \
+	      -e "s|^$$topsrcdirstrip/|$(top_builddir)/|;t"`; \
+	case $$dist_files in \
+	  */*) $(MKDIR_P) `echo "$$dist_files" | \
+			   sed '/\//!d;s|^|$(distdir)/|;s,/[^/]*$$,,' | \
+			   sort -u` ;; \
+	esac; \
+	for file in $$dist_files; do \
+	  if test -f $$file || test -d $$file; then d=.; else d=$(srcdir); fi; \
+	  if test -d $$d/$$file; then \
+	    dir=`echo "/$$file" | sed -e 's,/[^/]*$$,,'`; \
+	    if test -d "$(distdir)/$$file"; then \
+	      find "$(distdir)/$$file" -type d ! -perm -700 -exec chmod u+rwx {} \;; \
+	    fi; \
+	    if test -d $(srcdir)/$$file && test $$d != $(srcdir); then \
+	      cp -fpR $(srcdir)/$$file "$(distdir)$$dir" || exit 1; \
+	      find "$(distdir)/$$file" -type d ! -perm -700 -exec chmod u+rwx {} \;; \
+	    fi; \
+	    cp -fpR $$d/$$file "$(distdir)$$dir" || exit 1; \
+	  else \
+	    test -f "$(distdir)/$$file" \
+	    || cp -p $$d/$$file "$(distdir)/$$file" \
+	    || exit 1; \
+	  fi; \
+	done
+	$(MAKE) $(AM_MAKEFLAGS) \
+	  top_distdir="$(top_distdir)" distdir="$(distdir)" \
+	  dist-hook
+	-test -n "$(am__skip_mode_fix)" \
+	|| find "$(distdir)" -type d ! -perm -755 \
+		-exec chmod u+rwx,go+rx {} \; -o \
+	  ! -type d ! -perm -444 -links 1 -exec chmod a+r {} \; -o \
+	  ! -type d ! -perm -400 -exec chmod a+r {} \; -o \
+	  ! -type d ! -perm -444 -exec $(install_sh) -c -m a+r {} {} \; \
+	|| chmod -R a+r "$(distdir)"
+dist-gzip: distdir
+	tardir=$(distdir) && $(am__tar) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).tar.gz
+	$(am__post_remove_distdir)
+
+dist-bzip2: distdir
+	tardir=$(distdir) && $(am__tar) | BZIP2=$${BZIP2--9} bzip2 -c >$(distdir).tar.bz2
+	$(am__post_remove_distdir)
+
+dist-lzip: distdir
+	tardir=$(distdir) && $(am__tar) | lzip -c $${LZIP_OPT--9} >$(distdir).tar.lz
+	$(am__post_remove_distdir)
+dist-xz: distdir
+	tardir=$(distdir) && $(am__tar) | XZ_OPT=$${XZ_OPT--e} xz -c >$(distdir).tar.xz
+	$(am__post_remove_distdir)
+
+dist-zstd: distdir
+	tardir=$(distdir) && $(am__tar) | zstd -c $${ZSTD_CLEVEL-$${ZSTD_OPT--19}} >$(distdir).tar.zst
+	$(am__post_remove_distdir)
+
+dist-tarZ: distdir
+	@echo WARNING: "Support for distribution archives compressed with" \
+		       "legacy program 'compress' is deprecated." >&2
+	@echo WARNING: "It will be removed altogether in Automake 2.0" >&2
+	tardir=$(distdir) && $(am__tar) | compress -c >$(distdir).tar.Z
+	$(am__post_remove_distdir)
+
+dist-shar: distdir
+	@echo WARNING: "Support for shar distribution archives is" \
+	               "deprecated." >&2
+	@echo WARNING: "It will be removed altogether in Automake 2.0" >&2
+	shar $(distdir) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).shar.gz
+	$(am__post_remove_distdir)
+
+dist-zip: distdir
+	-rm -f $(distdir).zip
+	zip -rq $(distdir).zip $(distdir)
+	$(am__post_remove_distdir)
+
+dist dist-all:
+	$(MAKE) $(AM_MAKEFLAGS) $(DIST_TARGETS) am__post_remove_distdir='@:'
+	$(am__post_remove_distdir)
+
+# This target untars the dist file and tries a VPATH configuration.  Then
+# it guarantees that the distribution is self-contained by making another
+# tarfile.
+distcheck: dist
+	case '$(DIST_ARCHIVES)' in \
+	*.tar.gz*) \
+	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).tar.gz | $(am__untar) ;;\
+	*.tar.bz2*) \
+	  bzip2 -dc $(distdir).tar.bz2 | $(am__untar) ;;\
+	*.tar.lz*) \
+	  lzip -dc $(distdir).tar.lz | $(am__untar) ;;\
+	*.tar.xz*) \
+	  xz -dc $(distdir).tar.xz | $(am__untar) ;;\
+	*.tar.Z*) \
+	  uncompress -c $(distdir).tar.Z | $(am__untar) ;;\
+	*.shar.gz*) \
+	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).shar.gz | unshar ;;\
+	*.zip*) \
+	  unzip $(distdir).zip ;;\
+	*.tar.zst*) \
+	  zstd -dc $(distdir).tar.zst | $(am__untar) ;;\
+	esac
+	chmod -R a-w $(distdir)
+	chmod u+w $(distdir)
+	mkdir $(distdir)/_build $(distdir)/_build/sub $(distdir)/_inst
+	chmod a-w $(distdir)
+	test -d $(distdir)/_build || exit 0; \
+	dc_install_base=`$(am__cd) $(distdir)/_inst && pwd | sed -e 's,^[^:\\/]:[\\/],/,'` \
+	  && dc_destdir="$${TMPDIR-/tmp}/am-dc-$$$$/" \
+	  && am__cwd=`pwd` \
+	  && $(am__cd) $(distdir)/_build/sub \
+	  && ../../configure \
+	    $(AM_DISTCHECK_CONFIGURE_FLAGS) \
+	    $(DISTCHECK_CONFIGURE_FLAGS) \
+	    --srcdir=../.. --prefix="$$dc_install_base" \
+	  && $(MAKE) $(AM_MAKEFLAGS) \
+	  && $(MAKE) $(AM_MAKEFLAGS) $(AM_DISTCHECK_DVI_TARGET) \
+	  && $(MAKE) $(AM_MAKEFLAGS) check \
+	  && $(MAKE) $(AM_MAKEFLAGS) install \
+	  && $(MAKE) $(AM_MAKEFLAGS) installcheck \
+	  && $(MAKE) $(AM_MAKEFLAGS) uninstall \
+	  && $(MAKE) $(AM_MAKEFLAGS) distuninstallcheck_dir="$$dc_install_base" \
+	        distuninstallcheck \
+	  && chmod -R a-w "$$dc_install_base" \
+	  && ({ \
+	       (cd ../.. && umask 077 && mkdir "$$dc_destdir") \
+	       && $(MAKE) $(AM_MAKEFLAGS) DESTDIR="$$dc_destdir" install \
+	       && $(MAKE) $(AM_MAKEFLAGS) DESTDIR="$$dc_destdir" uninstall \
+	       && $(MAKE) $(AM_MAKEFLAGS) DESTDIR="$$dc_destdir" \
+	            distuninstallcheck_dir="$$dc_destdir" distuninstallcheck; \
+	      } || { rm -rf "$$dc_destdir"; exit 1; }) \
+	  && rm -rf "$$dc_destdir" \
+	  && $(MAKE) $(AM_MAKEFLAGS) dist \
+	  && rm -rf $(DIST_ARCHIVES) \
+	  && $(MAKE) $(AM_MAKEFLAGS) distcleancheck \
+	  && cd "$$am__cwd" \
+	  || exit 1
+	$(am__post_remove_distdir)
+	@(echo "$(distdir) archives ready for distribution: "; \
+	  list='$(DIST_ARCHIVES)'; for i in $$list; do echo $$i; done) | \
+	  sed -e 1h -e 1s/./=/g -e 1p -e 1x -e '$$p' -e '$$x'
+distuninstallcheck:
+	@test -n '$(distuninstallcheck_dir)' || { \
+	  echo 'ERROR: trying to run $@ with an empty' \
+	       '$$(distuninstallcheck_dir)' >&2; \
+	  exit 1; \
+	}; \
+	$(am__cd) '$(distuninstallcheck_dir)' || { \
+	  echo 'ERROR: cannot chdir into $(distuninstallcheck_dir)' >&2; \
+	  exit 1; \
+	}; \
+	test `$(am__distuninstallcheck_listfiles) | wc -l` -eq 0 \
+	   || { echo "ERROR: files left after uninstall:" ; \
+	        if test -n "$(DESTDIR)"; then \
+	          echo "  (check DESTDIR support)"; \
+	        fi ; \
+	        $(distuninstallcheck_listfiles) ; \
+	        exit 1; } >&2
+distcleancheck: distclean
+	@if test '$(srcdir)' = . ; then \
+	  echo "ERROR: distcleancheck can only run from a VPATH build" ; \
+	  exit 1 ; \
+	fi
+	@test `$(distcleancheck_listfiles) | wc -l` -eq 0 \
+	  || { echo "ERROR: files left in build directory after distclean:" ; \
+	       $(distcleancheck_listfiles) ; \
+	       exit 1; } >&2
+check-am: all-am
+	$(MAKE) $(AM_MAKEFLAGS) $(check_PROGRAMS)
+	$(MAKE) $(AM_MAKEFLAGS) check-TESTS
+check: $(BUILT_SOURCES)
+	$(MAKE) $(AM_MAKEFLAGS) check-am
+all-am: Makefile $(PROGRAMS) $(LTLIBRARIES) $(SCRIPTS) $(MANS) $(DATA) \
+		$(HEADERS) config.h
+install-binPROGRAMS: install-libLTLIBRARIES
+
+install-checkPROGRAMS: install-libLTLIBRARIES
+
+installdirs:
+	for dir in "$(DESTDIR)$(bindir)" "$(DESTDIR)$(libdir)" "$(DESTDIR)$(bindir)" "$(DESTDIR)$(man3dir)" "$(DESTDIR)$(man5dir)" "$(DESTDIR)$(pkgconfigdir)" "$(DESTDIR)$(pkgincludedir)" "$(DESTDIR)$(pkgincludedir)"; do \
+	  test -z "$$dir" || $(MKDIR_P) "$$dir"; \
+	done
+install: $(BUILT_SOURCES)
+	$(MAKE) $(AM_MAKEFLAGS) install-am
+install-exec: $(BUILT_SOURCES)
+	$(MAKE) $(AM_MAKEFLAGS) install-exec-am
+install-data: install-data-am
+uninstall: uninstall-am
+
+install-am: all-am
+	@$(MAKE) $(AM_MAKEFLAGS) install-exec-am install-data-am
+
+installcheck: installcheck-am
+install-strip:
+	if test -z '$(STRIP)'; then \
+	  $(MAKE) $(AM_MAKEFLAGS) INSTALL_PROGRAM="$(INSTALL_STRIP_PROGRAM)" \
+	    install_sh_PROGRAM="$(INSTALL_STRIP_PROGRAM)" INSTALL_STRIP_FLAG=-s \
+	      install; \
+	else \
+	  $(MAKE) $(AM_MAKEFLAGS) INSTALL_PROGRAM="$(INSTALL_STRIP_PROGRAM)" \
+	    install_sh_PROGRAM="$(INSTALL_STRIP_PROGRAM)" INSTALL_STRIP_FLAG=-s \
+	    "INSTALL_PROGRAM_ENV=STRIPPROG='$(STRIP)'" install; \
+	fi
+mostlyclean-generic:
+	-test -z "$(TEST_LOGS)" || rm -f $(TEST_LOGS)
+	-test -z "$(TEST_LOGS:.log=.trs)" || rm -f $(TEST_LOGS:.log=.trs)
+	-test -z "$(TEST_SUITE_LOG)" || rm -f $(TEST_SUITE_LOG)
+
+clean-generic:
+	-test -z "$(CLEANFILES)" || rm -f $(CLEANFILES)
+
+distclean-generic:
+	-test -z "$(CONFIG_CLEAN_FILES)" || rm -f $(CONFIG_CLEAN_FILES)
+	-test . = "$(srcdir)" || test -z "$(CONFIG_CLEAN_VPATH_FILES)" || rm -f $(CONFIG_CLEAN_VPATH_FILES)
+	-rm -f arm/$(DEPDIR)/$(am__dirstamp)
+	-rm -f arm/$(am__dirstamp)
+	-rm -f contrib/libtests/$(DEPDIR)/$(am__dirstamp)
+	-rm -f contrib/libtests/$(am__dirstamp)
+	-rm -f contrib/tools/$(DEPDIR)/$(am__dirstamp)
+	-rm -f contrib/tools/$(am__dirstamp)
+	-rm -f intel/$(DEPDIR)/$(am__dirstamp)
+	-rm -f intel/$(am__dirstamp)
+	-rm -f loongarch/$(DEPDIR)/$(am__dirstamp)
+	-rm -f loongarch/$(am__dirstamp)
+	-rm -f mips/$(DEPDIR)/$(am__dirstamp)
+	-rm -f mips/$(am__dirstamp)
+	-rm -f powerpc/$(DEPDIR)/$(am__dirstamp)
+	-rm -f powerpc/$(am__dirstamp)
+
+maintainer-clean-generic:
+	@echo "This command is intended for maintainers to use"
+	@echo "it deletes files that may require special tools to rebuild."
+	-test -z "$(BUILT_SOURCES)" || rm -f $(BUILT_SOURCES)
+	-test -z "$(MAINTAINERCLEANFILES)" || rm -f $(MAINTAINERCLEANFILES)
+@DO_INSTALL_LIBPNG_CONFIG_FALSE@@DO_INSTALL_LINKS_FALSE@install-exec-hook:
+@DO_INSTALL_LIBPNG_PC_FALSE@@DO_INSTALL_LINKS_FALSE@install-data-hook:
+@DO_INSTALL_LIBPNG_CONFIG_FALSE@@DO_INSTALL_LIBPNG_PC_FALSE@@DO_INSTALL_LINKS_FALSE@uninstall-hook:
+clean: clean-am
+
+clean-am: clean-binPROGRAMS clean-checkPROGRAMS clean-generic \
+	clean-libLTLIBRARIES clean-libtool clean-noinstLTLIBRARIES \
+	mostlyclean-am
+
+distclean: distclean-am
+	-rm -f $(am__CONFIG_DISTCLEAN_FILES)
+		-rm -f ./$(DEPDIR)/png.Plo
+	-rm -f ./$(DEPDIR)/pngerror.Plo
+	-rm -f ./$(DEPDIR)/pngget.Plo
+	-rm -f ./$(DEPDIR)/pngmem.Plo
+	-rm -f ./$(DEPDIR)/pngpread.Plo
+	-rm -f ./$(DEPDIR)/pngread.Plo
+	-rm -f ./$(DEPDIR)/pngrio.Plo
+	-rm -f ./$(DEPDIR)/pngrtran.Plo
+	-rm -f ./$(DEPDIR)/pngrutil.Plo
+	-rm -f ./$(DEPDIR)/pngset.Plo
+	-rm -f ./$(DEPDIR)/pngtest.Po
+	-rm -f ./$(DEPDIR)/pngtrans.Plo
+	-rm -f ./$(DEPDIR)/pngwio.Plo
+	-rm -f ./$(DEPDIR)/pngwrite.Plo
+	-rm -f ./$(DEPDIR)/pngwtran.Plo
+	-rm -f ./$(DEPDIR)/pngwutil.Plo
+	-rm -f arm/$(DEPDIR)/arm_init.Plo
+	-rm -f arm/$(DEPDIR)/filter_neon.Plo
+	-rm -f arm/$(DEPDIR)/filter_neon_intrinsics.Plo
+	-rm -f arm/$(DEPDIR)/palette_neon_intrinsics.Plo
+	-rm -f contrib/libtests/$(DEPDIR)/pngimage.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngstest.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngunknown.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngvalid.Po
+	-rm -f contrib/libtests/$(DEPDIR)/timepng.Po
+	-rm -f contrib/tools/$(DEPDIR)/png-fix-itxt.Po
+	-rm -f contrib/tools/$(DEPDIR)/pngcp.Po
+	-rm -f contrib/tools/$(DEPDIR)/pngfix.Po
+	-rm -f intel/$(DEPDIR)/filter_sse2_intrinsics.Plo
+	-rm -f intel/$(DEPDIR)/intel_init.Plo
+	-rm -f loongarch/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la-filter_lsx_intrinsics.Plo
+	-rm -f loongarch/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la-loongarch_lsx_init.Plo
+	-rm -f mips/$(DEPDIR)/filter_mmi_inline_assembly.Plo
+	-rm -f mips/$(DEPDIR)/filter_msa_intrinsics.Plo
+	-rm -f mips/$(DEPDIR)/mips_init.Plo
+	-rm -f powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo
+	-rm -f powerpc/$(DEPDIR)/powerpc_init.Plo
+	-rm -f Makefile
+distclean-am: clean-am distclean-compile distclean-generic \
+	distclean-hdr distclean-libtool distclean-tags
+
+dvi: dvi-am
+
+dvi-am:
+
+html: html-am
+
+html-am:
+
+info: info-am
+
+info-am:
+
+install-data-am: install-man install-nodist_pkgincludeHEADERS \
+	install-pkgconfigDATA install-pkgincludeHEADERS
+	@$(NORMAL_INSTALL)
+	$(MAKE) $(AM_MAKEFLAGS) install-data-hook
+install-dvi: install-dvi-am
+
+install-dvi-am:
+
+install-exec-am: install-binPROGRAMS install-binSCRIPTS \
+	install-libLTLIBRARIES
+	@$(NORMAL_INSTALL)
+	$(MAKE) $(AM_MAKEFLAGS) install-exec-hook
+install-html: install-html-am
+
+install-html-am:
+
+install-info: install-info-am
+
+install-info-am:
+
+install-man: install-man3 install-man5
+
+install-pdf: install-pdf-am
+
+install-pdf-am:
+
+install-ps: install-ps-am
+
+install-ps-am:
+
+installcheck-am:
+
+maintainer-clean: maintainer-clean-am
+	-rm -f $(am__CONFIG_DISTCLEAN_FILES)
+	-rm -rf $(top_srcdir)/autom4te.cache
+		-rm -f ./$(DEPDIR)/png.Plo
+	-rm -f ./$(DEPDIR)/pngerror.Plo
+	-rm -f ./$(DEPDIR)/pngget.Plo
+	-rm -f ./$(DEPDIR)/pngmem.Plo
+	-rm -f ./$(DEPDIR)/pngpread.Plo
+	-rm -f ./$(DEPDIR)/pngread.Plo
+	-rm -f ./$(DEPDIR)/pngrio.Plo
+	-rm -f ./$(DEPDIR)/pngrtran.Plo
+	-rm -f ./$(DEPDIR)/pngrutil.Plo
+	-rm -f ./$(DEPDIR)/pngset.Plo
+	-rm -f ./$(DEPDIR)/pngtest.Po
+	-rm -f ./$(DEPDIR)/pngtrans.Plo
+	-rm -f ./$(DEPDIR)/pngwio.Plo
+	-rm -f ./$(DEPDIR)/pngwrite.Plo
+	-rm -f ./$(DEPDIR)/pngwtran.Plo
+	-rm -f ./$(DEPDIR)/pngwutil.Plo
+	-rm -f arm/$(DEPDIR)/arm_init.Plo
+	-rm -f arm/$(DEPDIR)/filter_neon.Plo
+	-rm -f arm/$(DEPDIR)/filter_neon_intrinsics.Plo
+	-rm -f arm/$(DEPDIR)/palette_neon_intrinsics.Plo
+	-rm -f contrib/libtests/$(DEPDIR)/pngimage.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngstest.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngunknown.Po
+	-rm -f contrib/libtests/$(DEPDIR)/pngvalid.Po
+	-rm -f contrib/libtests/$(DEPDIR)/timepng.Po
+	-rm -f contrib/tools/$(DEPDIR)/png-fix-itxt.Po
+	-rm -f contrib/tools/$(DEPDIR)/pngcp.Po
+	-rm -f contrib/tools/$(DEPDIR)/pngfix.Po
+	-rm -f intel/$(DEPDIR)/filter_sse2_intrinsics.Plo
+	-rm -f intel/$(DEPDIR)/intel_init.Plo
+	-rm -f loongarch/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la-filter_lsx_intrinsics.Plo
+	-rm -f loongarch/$(DEPDIR)/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@lsx_la-loongarch_lsx_init.Plo
+	-rm -f mips/$(DEPDIR)/filter_mmi_inline_assembly.Plo
+	-rm -f mips/$(DEPDIR)/filter_msa_intrinsics.Plo
+	-rm -f mips/$(DEPDIR)/mips_init.Plo
+	-rm -f powerpc/$(DEPDIR)/filter_vsx_intrinsics.Plo
+	-rm -f powerpc/$(DEPDIR)/powerpc_init.Plo
+	-rm -f Makefile
+maintainer-clean-am: distclean-am maintainer-clean-generic
+
+mostlyclean: mostlyclean-am
+
+mostlyclean-am: mostlyclean-compile mostlyclean-generic \
+	mostlyclean-libtool
+
+pdf: pdf-am
+
+pdf-am:
+
+ps: ps-am
+
+ps-am:
+
+uninstall-am: uninstall-binPROGRAMS uninstall-binSCRIPTS \
+	uninstall-libLTLIBRARIES uninstall-man \
+	uninstall-nodist_pkgincludeHEADERS uninstall-pkgconfigDATA \
+	uninstall-pkgincludeHEADERS
+	@$(NORMAL_INSTALL)
+	$(MAKE) $(AM_MAKEFLAGS) uninstall-hook
+uninstall-man: uninstall-man3 uninstall-man5
+
+.MAKE: all check check-am install install-am install-data-am \
+	install-exec install-exec-am install-strip uninstall-am
+
+.PHONY: CTAGS GTAGS TAGS all all-am am--depfiles am--refresh check \
+	check-TESTS check-am clean clean-binPROGRAMS \
+	clean-checkPROGRAMS clean-cscope clean-generic \
+	clean-libLTLIBRARIES clean-libtool clean-noinstLTLIBRARIES \
+	cscope cscopelist-am ctags ctags-am dist dist-all dist-bzip2 \
+	dist-gzip dist-hook dist-lzip dist-shar dist-tarZ dist-xz \
+	dist-zip dist-zstd distcheck distclean distclean-compile \
+	distclean-generic distclean-hdr distclean-libtool \
+	distclean-tags distcleancheck distdir distuninstallcheck dvi \
+	dvi-am html html-am info info-am install install-am \
+	install-binPROGRAMS install-binSCRIPTS install-data \
+	install-data-am install-data-hook install-dvi install-dvi-am \
+	install-exec install-exec-am install-exec-hook install-html \
+	install-html-am install-info install-info-am \
+	install-libLTLIBRARIES install-man install-man3 install-man5 \
+	install-nodist_pkgincludeHEADERS install-pdf install-pdf-am \
+	install-pkgconfigDATA install-pkgincludeHEADERS install-ps \
+	install-ps-am install-strip installcheck installcheck-am \
+	installdirs maintainer-clean maintainer-clean-generic \
+	mostlyclean mostlyclean-compile mostlyclean-generic \
+	mostlyclean-libtool pdf pdf-am ps ps-am recheck tags tags-am \
+	uninstall uninstall-am uninstall-binPROGRAMS \
+	uninstall-binSCRIPTS uninstall-hook uninstall-libLTLIBRARIES \
+	uninstall-man uninstall-man3 uninstall-man5 \
+	uninstall-nodist_pkgincludeHEADERS uninstall-pkgconfigDATA \
+	uninstall-pkgincludeHEADERS
+
+.PRECIOUS: Makefile
+
+
+$(PNGLIB_BASENAME).pc: libpng.pc
+	cp libpng.pc $@
+
+$(PNGLIB_BASENAME)-config: libpng-config
+	cp libpng-config $@
+
+scripts/sym.out scripts/vers.out: png.h pngconf.h pnglibconf.h
+scripts/prefix.out: png.h pngconf.h pnglibconf.out
+scripts/symbols.out: png.h pngconf.h $(srcdir)/scripts/pnglibconf.h.prebuilt
+scripts/intprefix.out: pnglibconf.h
+
+libpng.sym: scripts/sym.out
+	rm -f $@
+	cp $? $@
+libpng.vers: scripts/vers.out
+	rm -f $@
+	cp $? $@
+
+# Rename functions in scripts/prefix.out with a PNG_PREFIX prefix.
+# Rename macros in scripts/macro.lst from PNG_PREFIXpng_ to PNG_ (the actual
+# implementation of the macro).
+@DO_PNG_PREFIX_TRUE@pnglibconf.h: pnglibconf.out scripts/prefix.out scripts/macro.lst
+@DO_PNG_PREFIX_TRUE@	rm -f $@
+@DO_PNG_PREFIX_TRUE@	$(AWK) 's==0 && NR>1{print prev}\
+@DO_PNG_PREFIX_TRUE@	   s==0{prev=$$0}\
+@DO_PNG_PREFIX_TRUE@	   s==1{print "#define", $$1, "@PNG_PREFIX@" $$1}\
+@DO_PNG_PREFIX_TRUE@	   s==2{print "#define @PNG_PREFIX@png_" $$1, "PNG_" $$1}\
+@DO_PNG_PREFIX_TRUE@	   END{print prev}' s=0 pnglibconf.out s=1 scripts/prefix.out\
+@DO_PNG_PREFIX_TRUE@	   s=2 ${srcdir}/scripts/macro.lst >pnglibconf.tf8
+@DO_PNG_PREFIX_TRUE@	mv pnglibconf.tf8 $@
+
+@DO_PNG_PREFIX_TRUE@pngprefix.h: scripts/intprefix.out
+@DO_PNG_PREFIX_TRUE@	rm -f pngprefix.tf1
+@DO_PNG_PREFIX_TRUE@	$(AWK) '{print "#define", $$1, "@PNG_PREFIX@" $$1}' $? >pngprefix.tf1
+@DO_PNG_PREFIX_TRUE@	mv pngprefix.tf1 $@
+@DO_PNG_PREFIX_FALSE@pnglibconf.h: pnglibconf.out
+@DO_PNG_PREFIX_FALSE@	rm -f $@
+@DO_PNG_PREFIX_FALSE@	cp $? $@
+
+@DO_PNG_PREFIX_FALSE@pngprefix.h: # is empty
+@DO_PNG_PREFIX_FALSE@	:>$@
+
+$(srcdir)/scripts/pnglibconf.h.prebuilt:
+	@echo "Attempting to build $@" >&2
+	@echo "This is a machine generated file, but if you want to make" >&2
+	@echo "a new one simply make 'scripts/pnglibconf.out', copy that" >&2
+	@echo "AND set PNG_ZLIB_VERNUM to 0 (you MUST do this)" >&2
+	@exit 1
+
+# The following is necessary to ensure that the local pnglibconf.h is used, not
+# an installed one (this can happen immediately after on a clean system if
+# 'make test' is the first thing the user does.)  Only files which include
+# one of the png source files (typically png.h or pngpriv.h) need to be listed
+# here:
+pngtest.o: pnglibconf.h
+
+contrib/libtests/makepng.o: pnglibconf.h
+contrib/libtests/pngstest.o: pnglibconf.h
+contrib/libtests/pngunknown.o: pnglibconf.h
+contrib/libtests/pngimage.o: pnglibconf.h
+contrib/libtests/pngvalid.o: pnglibconf.h
+contrib/libtests/readpng.o: pnglibconf.h
+contrib/libtests/tarith.o: pnglibconf.h
+contrib/libtests/timepng.o: pnglibconf.h
+
+contrib/tools/makesRGB.o: pnglibconf.h
+contrib/tools/pngfix.o: pnglibconf.h
+contrib/tools/pngcp.o: pnglibconf.h
+
+.c.out:
+	rm -f $@ $*.tf[12]
+	test -d scripts || mkdir scripts || test -d scripts
+	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES)\
+	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $< > $*.tf1
+	$(AWK) -f "${srcdir}/scripts/dfn.awk" out="$*.tf2" $*.tf1 1>&2
+	rm -f $*.tf1
+	mv $*.tf2 $@
+
+# The .c file for pnglibconf.h is machine generated
+pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+	rm -f $@ $*.tf[45]
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf4 version=search\
+	    ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+	    ${srcdir}/pngusr.dfa $(DFA_XTRA) 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf5 $*.tf4 1>&2
+	rm $*.tf4
+	mv $*.tf5 $@
+
+# Symbol checks (.def and .out files should match)
+scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.out
+
+.out.chk:
+	rm -f $@ $*.new
+	$(AWK) -f ${srcdir}/scripts/checksym.awk ${srcdir}/scripts/${*F}.def\
+	    of="$*.new" $< >&2
+	mv $*.new $@
+
+# used on demand to regenerate the standard header, CPPFLAGS should
+# be empty - no non-standard defines
+scripts/pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
+	rm -f $@ pnglibconf.tf[67]
+	test -z "$(CPPFLAGS)"
+	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf6\
+	    logunsupported=1 version=search ${srcdir}/pngconf.h -\
+	    ${srcdir}/scripts/pnglibconf.dfa 1>&2
+	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf7\
+	    pnglibconf.tf6 1>&2
+	rm pnglibconf.tf6
+	mv pnglibconf.tf7 $@
+
+$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS): png.h pngconf.h \
+	pnglibconf.h pngpriv.h pngdebug.h pnginfo.h pngstruct.h pngprefix.h
+
+test: check-am
+
+# Extra checks
+check: scripts/symbols.chk
+
+# Don't distribute the generated script files
+dist-hook:
+	cd '$(top_distdir)'; rm -f $(SCRIPT_CLEANFILES)
+
+# Make links between installed files with release-specific names and the generic
+# file names.  If this install rule is run the generic names will be deleted and
+# recreated - this has obvious issues for systems with multiple installations.
+
+install-header-links:
+	@set -ex; cd '$(DESTDIR)$(includedir)'; for f in $(HEADERS); do \
+	   rm -f "$$f"; $(LN_S) "$(PNGLIB_BASENAME)/$$f" "$$f"; done
+
+uninstall-header-links:
+	cd '$(DESTDIR)$(includedir)'; rm -f $(HEADERS)
+
+install-libpng-pc:
+	@set -ex; cd '$(DESTDIR)$(pkgconfigdir)'; rm -f libpng.pc; \
+	   $(LN_S) '$(PNGLIB_BASENAME).pc' libpng.pc
+
+uninstall-libpng-pc:
+	rm -f '$(DESTDIR)$(pkgconfigdir)/libpng.pc'
+
+install-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)';\
+	for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext";\
+           if test -f "$(PNGLIB_BASENAME).$$ext"; then\
+              $(LN_S) "$(PNGLIB_BASENAME).$$ext" "libpng.$$ext" || exit 1;\
+           fi;\
+	done
+
+uninstall-library-links:
+	@set -x; cd '$(DESTDIR)$(libdir)'; for ext in $(EXT_LIST); do\
+	   rm -f "libpng.$$ext"; done
+
+install-libpng-config:
+	@set -ex; cd '$(DESTDIR)$(bindir)'; rm -f libpng-config; \
+	   $(LN_S) '$(PNGLIB_BASENAME)-config' libpng-config
+
+uninstall-libpng-config:
+	rm -f '$(DESTDIR)$(bindir)/libpng-config'
+
+# If --enable-unversioned-links is specified the header and lib file links
+# will be automatically made on a 'make install':
+
+@DO_INSTALL_LINKS_TRUE@install-data-hook: install-header-links
+@DO_INSTALL_LINKS_TRUE@uninstall-hook: uninstall-header-links
+@DO_INSTALL_LINKS_TRUE@install-exec-hook: install-library-links
+@DO_INSTALL_LINKS_TRUE@uninstall-hook: uninstall-library-links
+
+# Likewise, --install-pc causes libpng.pc to be constructed:
+
+@DO_INSTALL_LIBPNG_PC_TRUE@install-data-hook: install-libpng-pc
+@DO_INSTALL_LIBPNG_PC_TRUE@uninstall-hook: uninstall-libpng-pc
+
+# And --install-config:
+
+@DO_INSTALL_LIBPNG_CONFIG_TRUE@install-exec-hook: install-libpng-config
+@DO_INSTALL_LIBPNG_CONFIG_TRUE@uninstall-hook: uninstall-libpng-config
+
+# The following addition ensures that 'make all' always builds the test programs
+# too.  It used to, but some change either in libpng or configure stopped this
+# working.
+all-am: $(check_PROGRAMS)
+
+# Tell versions [3.59,3.63) of GNU make to not export all variables.
+# Otherwise a system limit (for SysV at least) may be exceeded.
+.NOEXPORT:
Index: /trunk/src/libs/libpng-1.6.45/Makefile.kmk
===================================================================
--- /trunk/src/libs/libpng-1.6.45/Makefile.kmk	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/Makefile.kmk	(revision 107811)
@@ -0,0 +1,58 @@
+# $Id$
+## @file
+# Sub-Makefile for libpng.
+#
+
+#
+# Copyright (C) 2006-2024 Oracle and/or its affiliates.
+#
+# This file is part of VirtualBox base platform packages, as
+# available from https://www.virtualbox.org.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation, in version 3 of the
+# License.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, see <https://www.gnu.org/licenses>.
+#
+# SPDX-License-Identifier: GPL-3.0-only
+#
+
+SUB_DEPTH = ../../..
+include $(KBUILD_PATH)/subheader.kmk
+
+LIBRARIES += VBox-libpng
+VBox-libpng_TEMPLATE = VBoxR3DllNonPedantic
+VBox-libpng_SDKS = VBoxZlib
+VBox-libpng_CFLAGS.win = -wd4310
+# -wd2220 -wd4431 # pngrutil.c(1268) : warning C4310: cast truncates constant value
+VBox-libpng_SOURCES = \
+	png.c \
+	pngset.c \
+	pngget.c \
+	pngrutil.c \
+	pngtrans.c \
+	pngwutil.c \
+	pngread.c \
+	pngrio.c \
+	pngwio.c \
+	pngwrite.c \
+	pngrtran.c \
+	pngwtran.c \
+	pngmem.c \
+	pngerror.c \
+	pngpread.c
+VBox-libpng_SOURCES.arm64 = \
+	arm/arm_init.c \
+	arm/filter_neon_intrinsics.c \
+	arm/palette_neon_intrinsics.c
+
+include $(FILE_KBUILD_SUB_FOOTER)
+
Index: /trunk/src/libs/libpng-1.6.45/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/README	(revision 107811)
@@ -0,0 +1,184 @@
+README for libpng version 1.6.43
+================================
+
+See the note about version numbers near the top of `png.h`.
+See `INSTALL` for instructions on how to install libpng.
+
+Libpng comes in several distribution formats.  Get `libpng-*.tar.gz`
+or `libpng-*.tar.xz` if you want UNIX-style line endings in the text
+files, or `lpng*.7z` or `lpng*.zip` if you want DOS-style line endings.
+
+For a detailed description on using libpng, read `libpng-manual.txt`.
+For examples of libpng in a program, see `example.c` and `pngtest.c`.
+For usage information and restrictions (what little they are) on libpng,
+see `png.h`.  For a description on using zlib (the compression library
+used by libpng) and zlib's restrictions, see `zlib.h`.
+
+You should use zlib 1.0.4 or later to run this, but it _may_ work with
+versions as old as zlib 0.95.  Even so, there are bugs in older zlib
+versions which can cause the output of invalid compression streams for
+some images.
+
+You should also note that zlib is a compression library that is useful
+for more things than just PNG files.  You can use zlib as a drop-in
+replacement for `fread()` and `fwrite()`, if you are so inclined.
+
+zlib should be available at the same place that libpng is, or at
+https://zlib.net .
+
+You may also want a copy of the PNG specification.  It is available
+as an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find
+these at http://www.libpng.org/pub/png/pngdocs.html .
+
+This code is currently being archived at https://libpng.sourceforge.io
+in the download area, and at http://libpng.download/src .
+
+This release, based in a large way on Glenn's, Guy's and Andreas'
+earlier work, was created and will be supported by myself and the PNG
+development group.
+
+Send comments, corrections and commendations to `png-mng-implement`
+at `lists.sourceforge.net`.  (Subscription is required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe.)
+
+Send general questions about the PNG specification to `png-mng-misc`
+at `lists.sourceforge.net`.  (Subscription is required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-misc
+to subscribe.)
+
+Historical notes
+----------------
+
+The libpng library has been in extensive use and testing since mid-1995.
+Version 0.89, published a year later, was the first official release.
+By late 1997, it had finally gotten to the stage where there hadn't
+been significant changes to the API in some time, and people have a bad
+feeling about libraries with versions below 1.0.  Version 1.0.0 was
+released in March 1998.
+
+Note that some of the changes to the `png_info` structure render this
+version of the library binary incompatible with libpng-0.89 or
+earlier versions if you are using a shared library.  The type of the
+`filler` parameter for `png_set_filler()` has changed from `png_byte`
+to `png_uint_32`, which will affect shared-library applications that
+use this function.
+
+To avoid problems with changes to the internals of the `info_struct`,
+new APIs have been made available in 0.95 to avoid direct application
+access to `info_ptr`.  These functions are the `png_set_<chunk>` and
+`png_get_<chunk>` functions.  These functions should be used when
+accessing/storing the `info_struct` data, rather than manipulating it
+directly, to avoid such problems in the future.
+
+It is important to note that the APIs did not make current programs
+that access the info struct directly incompatible with the new
+library, through libpng-1.2.x.  In libpng-1.4.x, which was meant to
+be a transitional release, members of the `png_struct` and the
+`info_struct` can still be accessed, but the compiler will issue a
+warning about deprecated usage.  Since libpng-1.5.0, direct access
+to these structs is not allowed, and the definitions of the structs
+reside in private `pngstruct.h` and `pnginfo.h` header files that are
+not accessible to applications.  It is strongly suggested that new
+programs use the new APIs (as shown in `example.c` and `pngtest.c`),
+and older programs be converted to the new format, to facilitate
+upgrades in the future.
+
+The additions since 0.89 include the ability to read from a PNG stream
+which has had some (or all) of the signature bytes read by the calling
+application.  This also allows the reading of embedded PNG streams that
+do not have the PNG file signature.  As well, it is now possible to set
+the library action on the detection of chunk CRC errors.  It is possible
+to set different actions based on whether the CRC error occurred in a
+critical or an ancillary chunk.
+
+The additions since 0.90 include the ability to compile libpng as a
+Windows DLL, and new APIs for accessing data in the `info_struct`.
+Experimental functions included the ability to set weighting and cost
+factors for row filter selection, direct reads of integers from buffers
+on big-endian processors that support misaligned data access, faster
+methods of doing alpha composition, and more accurate 16-to-8 bit color
+conversion.  Some of these experimental functions, such as the weighted
+filter heuristics, have since been removed.
+
+Files included in this distribution
+-----------------------------------
+
+    ANNOUNCE      =>  Announcement of this version, with recent changes
+    AUTHORS       =>  List of contributing authors
+    CHANGES       =>  Description of changes between libpng versions
+    INSTALL       =>  Instructions to install libpng
+    LICENSE       =>  License to use and redistribute libpng
+    README        =>  This file
+    TODO          =>  Things not implemented in the current library
+    TRADEMARK     =>  Trademark information
+    example.c     =>  Example code for using libpng functions
+    libpng.3      =>  Manual page for libpng (includes libpng-manual.txt)
+    libpng-manual.txt  =>  Description of libpng and its functions
+    libpngpf.3    =>  Manual page for libpng's private functions (deprecated)
+    png.5         =>  Manual page for the PNG format
+    png.c         =>  Basic interface functions common to library
+    png.h         =>  Library function and interface declarations (public)
+    pngpriv.h     =>  Library function and interface declarations (private)
+    pngconf.h     =>  System specific library configuration (public)
+    pngstruct.h   =>  png_struct declaration (private)
+    pnginfo.h     =>  png_info struct declaration (private)
+    pngdebug.h    =>  debugging macros (private)
+    pngerror.c    =>  Error/warning message I/O functions
+    pngget.c      =>  Functions for retrieving info from struct
+    pngmem.c      =>  Memory handling functions
+    pngbar.png    =>  PNG logo, 88x31
+    pngnow.png    =>  PNG logo, 98x31
+    pngpread.c    =>  Progressive reading functions
+    pngread.c     =>  Read data/helper high-level functions
+    pngrio.c      =>  Lowest-level data read I/O functions
+    pngrtran.c    =>  Read data transformation functions
+    pngrutil.c    =>  Read data utility functions
+    pngset.c      =>  Functions for storing data into the info_struct
+    pngtest.c     =>  Library test program
+    pngtest.png   =>  Library test sample image
+    pngtrans.c    =>  Common data transformation functions
+    pngwio.c      =>  Lowest-level write I/O functions
+    pngwrite.c    =>  High-level write functions
+    pngwtran.c    =>  Write data transformations
+    pngwutil.c    =>  Write utility functions
+    arm/          =>  Optimized code for ARM Neon
+    intel/        =>  Optimized code for INTEL SSE2
+    loongarch/    =>  Optimized code for LoongArch LSX
+    mips/         =>  Optimized code for MIPS MSA and MIPS MMI
+    powerpc/      =>  Optimized code for PowerPC VSX
+    ci/           =>  Scripts for continuous integration
+    contrib/      =>  External contributions
+        arm-neon/     =>  Optimized code for the ARM-NEON platform
+        mips-msa/     =>  Optimized code for the MIPS-MSA platform
+        powerpc-vsx/  =>  Optimized code for the POWERPC-VSX platform
+        examples/     =>  Examples of libpng usage
+        gregbook/     =>  Source code for PNG reading and writing, from
+                          "PNG: The Definitive Guide" by Greg Roelofs,
+                          O'Reilly, 1999
+        libtests/     =>  Test programs
+        oss-fuzz/     =>  Files used by the OSS-Fuzz project for fuzz-testing
+                          libpng
+        pngexif/      =>  Program to inspect the EXIF information in PNG files
+        pngminim/     =>  Minimal decoder, encoder, and progressive decoder
+                          programs demonstrating the use of pngusr.dfa
+        pngminus/     =>  Simple pnm2png and png2pnm programs
+        pngsuite/     =>  Test images
+        testpngs/     =>  Test images
+        tools/        =>  Various tools
+        visupng/      =>  VisualPng, a Windows viewer for PNG images
+    projects/     =>  Project files and workspaces for various IDEs
+        owatcom/      =>  OpenWatcom project
+        visualc71/    =>  Microsoft Visual C++ 7.1 workspace
+        vstudio/      =>  Microsoft Visual Studio workspace
+    scripts/      =>  Scripts and makefiles for building libpng
+                      (see scripts/README.txt for the complete list)
+    tests/        =>  Test scripts
+
+Good luck, and happy coding!
+
+ * Cosmin Truta (current maintainer, since 2018)
+ * Glenn Randers-Pehrson (former maintainer, 1998-2018)
+ * Andreas Eric Dilger (former maintainer, 1996-1997)
+ * Guy Eric Schalnat (original author and former maintainer, 1995-1996)
+   (formerly of Group 42, Inc.)
Index: /trunk/src/libs/libpng-1.6.45/TODO
===================================================================
--- /trunk/src/libs/libpng-1.6.45/TODO	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/TODO	(revision 107811)
@@ -0,0 +1,23 @@
+TODO - list of things to do for libpng:
+
+* Fix all defects (duh!)
+* Better C++ wrapper / full C++ implementation (?)
+* Fix the problems with C++ and 'extern "C"'.
+* cHRM transformation.
+* Palette creation.
+* "grayscale->palette" transformation and "palette->grayscale" detection.
+* Improved dithering.
+* Multi-lingual error and warning message support.
+* Complete sRGB transformation.  (Currently it simply uses gamma=0.45455.)
+* Man pages for function calls.
+* Better documentation.
+* Better filter selection
+  (e.g., counting huffman bits/precompression; filter inertia; filter costs).
+* Histogram creation.
+* Text conversion between different code pages (e.g., Latin-1 -> Mac).
+* Avoid building gamma tables whenever possible.
+* Greater precision in changing to linear gamma for compositing against
+  background, and in doing rgb-to-gray transformations.
+* Investigate pre-incremented loop counters and other loop constructions.
+* Interpolated method of handling interlacing.
+* More validations for libpng transformations.
Index: /trunk/src/libs/libpng-1.6.45/TRADEMARK
===================================================================
--- /trunk/src/libs/libpng-1.6.45/TRADEMARK	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/TRADEMARK	(revision 107811)
@@ -0,0 +1,8 @@
+TRADEMARK
+=========
+
+The name "libpng" has not been registered by the Copyright owners
+as a trademark in any jurisdiction.  However, because libpng has
+been distributed and maintained world-wide, continually since 1995,
+the Copyright owners claim "common-law trademark protection" in any
+jurisdiction where common-law trademark is recognized.
Index: /trunk/src/libs/libpng-1.6.45/aclocal.m4
===================================================================
--- /trunk/src/libs/libpng-1.6.45/aclocal.m4	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/aclocal.m4	(revision 107811)
@@ -0,0 +1,1211 @@
+# generated automatically by aclocal 1.16.5 -*- Autoconf -*-
+
+# Copyright (C) 1996-2021 Free Software Foundation, Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY, to the extent permitted by law; without
+# even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE.
+
+m4_ifndef([AC_CONFIG_MACRO_DIRS], [m4_defun([_AM_CONFIG_MACRO_DIRS], [])m4_defun([AC_CONFIG_MACRO_DIRS], [_AM_CONFIG_MACRO_DIRS($@)])])
+m4_ifndef([AC_AUTOCONF_VERSION],
+  [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
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+If you have problems, you may need to regenerate the build system entirely.
+To do so, use the procedure documented by the package, typically 'autoreconf'.])])
+
+# Copyright (C) 2002-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_AUTOMAKE_VERSION(VERSION)
+# ----------------------------
+# Automake X.Y traces this macro to ensure aclocal.m4 has been
+# generated from the m4 files accompanying Automake X.Y.
+# (This private macro should not be called outside this file.)
+AC_DEFUN([AM_AUTOMAKE_VERSION],
+[am__api_version='1.16'
+dnl Some users find AM_AUTOMAKE_VERSION and mistake it for a way to
+dnl require some minimum version.  Point them to the right macro.
+m4_if([$1], [1.16.5], [],
+      [AC_FATAL([Do not call $0, use AM_INIT_AUTOMAKE([$1]).])])dnl
+])
+
+# _AM_AUTOCONF_VERSION(VERSION)
+# -----------------------------
+# aclocal traces this macro to find the Autoconf version.
+# This is a private macro too.  Using m4_define simplifies
+# the logic in aclocal, which can simply ignore this definition.
+m4_define([_AM_AUTOCONF_VERSION], [])
+
+# AM_SET_CURRENT_AUTOMAKE_VERSION
+# -------------------------------
+# Call AM_AUTOMAKE_VERSION and AM_AUTOMAKE_VERSION so they can be traced.
+# This function is AC_REQUIREd by AM_INIT_AUTOMAKE.
+AC_DEFUN([AM_SET_CURRENT_AUTOMAKE_VERSION],
+[AM_AUTOMAKE_VERSION([1.16.5])dnl
+m4_ifndef([AC_AUTOCONF_VERSION],
+  [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
+_AM_AUTOCONF_VERSION(m4_defn([AC_AUTOCONF_VERSION]))])
+
+# Figure out how to run the assembler.                      -*- Autoconf -*-
+
+# Copyright (C) 2001-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_PROG_AS
+# ----------
+AC_DEFUN([AM_PROG_AS],
+[# By default we simply use the C compiler to build assembly code.
+AC_REQUIRE([AC_PROG_CC])
+test "${CCAS+set}" = set || CCAS=$CC
+test "${CCASFLAGS+set}" = set || CCASFLAGS=$CFLAGS
+AC_ARG_VAR([CCAS],      [assembler compiler command (defaults to CC)])
+AC_ARG_VAR([CCASFLAGS], [assembler compiler flags (defaults to CFLAGS)])
+_AM_IF_OPTION([no-dependencies],, [_AM_DEPENDENCIES([CCAS])])dnl
+])
+
+# AM_AUX_DIR_EXPAND                                         -*- Autoconf -*-
+
+# Copyright (C) 2001-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# For projects using AC_CONFIG_AUX_DIR([foo]), Autoconf sets
+# $ac_aux_dir to '$srcdir/foo'.  In other projects, it is set to
+# '$srcdir', '$srcdir/..', or '$srcdir/../..'.
+#
+# Of course, Automake must honor this variable whenever it calls a
+# tool from the auxiliary directory.  The problem is that $srcdir (and
+# therefore $ac_aux_dir as well) can be either absolute or relative,
+# depending on how configure is run.  This is pretty annoying, since
+# it makes $ac_aux_dir quite unusable in subdirectories: in the top
+# source directory, any form will work fine, but in subdirectories a
+# relative path needs to be adjusted first.
+#
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+#    fails when called from a subdirectory if $ac_aux_dir is relative
+# $top_srcdir/$ac_aux_dir/missing
+#    fails if $ac_aux_dir is absolute,
+#    fails when called from a subdirectory in a VPATH build with
+#          a relative $ac_aux_dir
+#
+# The reason of the latter failure is that $top_srcdir and $ac_aux_dir
+# are both prefixed by $srcdir.  In an in-source build this is usually
+# harmless because $srcdir is '.', but things will broke when you
+# start a VPATH build or use an absolute $srcdir.
+#
+# So we could use something similar to $top_srcdir/$ac_aux_dir/missing,
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+#   am_aux_dir='\$(top_srcdir)/'`expr "$ac_aux_dir" : "$srcdir//*\(.*\)"`
+# and then we would define $MISSING as
+#   MISSING="\${SHELL} $am_aux_dir/missing"
+# This will work as long as MISSING is not called from configure, because
+# unfortunately $(top_srcdir) has no meaning in configure.
+# However there are other variables, like CC, which are often used in
+# configure, and could therefore not use this "fixed" $ac_aux_dir.
+#
+# Another solution, used here, is to always expand $ac_aux_dir to an
+# absolute PATH.  The drawback is that using absolute paths prevent a
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+
+AC_DEFUN([AM_AUX_DIR_EXPAND],
+[AC_REQUIRE([AC_CONFIG_AUX_DIR_DEFAULT])dnl
+# Expand $ac_aux_dir to an absolute path.
+am_aux_dir=`cd "$ac_aux_dir" && pwd`
+])
+
+# AM_CONDITIONAL                                            -*- Autoconf -*-
+
+# Copyright (C) 1997-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_CONDITIONAL(NAME, SHELL-CONDITION)
+# -------------------------------------
+# Define a conditional.
+AC_DEFUN([AM_CONDITIONAL],
+[AC_PREREQ([2.52])dnl
+ m4_if([$1], [TRUE],  [AC_FATAL([$0: invalid condition: $1])],
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+_AM_SUBST_NOTMAKE([$1_TRUE])dnl
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+m4_define([_AM_COND_VALUE_$1], [$2])dnl
+if $2; then
+  $1_TRUE=
+  $1_FALSE='#'
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+  $1_TRUE='#'
+  $1_FALSE=
+fi
+AC_CONFIG_COMMANDS_PRE(
+[if test -z "${$1_TRUE}" && test -z "${$1_FALSE}"; then
+  AC_MSG_ERROR([[conditional "$1" was never defined.
+Usually this means the macro was only invoked conditionally.]])
+fi])])
+
+# Copyright (C) 1999-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+
+# There are a few dirty hacks below to avoid letting 'AC_PROG_CC' be
+# written in clear, in which case automake, when reading aclocal.m4,
+# will think it sees a *use*, and therefore will trigger all it's
+# C support machinery.  Also note that it means that autoscan, seeing
+# CC etc. in the Makefile, will ask for an AC_PROG_CC use...
+
+
+# _AM_DEPENDENCIES(NAME)
+# ----------------------
+# See how the compiler implements dependency checking.
+# NAME is "CC", "CXX", "OBJC", "OBJCXX", "UPC", or "GJC".
+# We try a few techniques and use that to set a single cache variable.
+#
+# We don't AC_REQUIRE the corresponding AC_PROG_CC since the latter was
+# modified to invoke _AM_DEPENDENCIES(CC); we would have a circular
+# dependency, and given that the user is not expected to run this macro,
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+AC_DEFUN([_AM_DEPENDENCIES],
+[AC_REQUIRE([AM_SET_DEPDIR])dnl
+AC_REQUIRE([AM_OUTPUT_DEPENDENCY_COMMANDS])dnl
+AC_REQUIRE([AM_MAKE_INCLUDE])dnl
+AC_REQUIRE([AM_DEP_TRACK])dnl
+
+m4_if([$1], [CC],   [depcc="$CC"   am_compiler_list=],
+      [$1], [CXX],  [depcc="$CXX"  am_compiler_list=],
+      [$1], [OBJC], [depcc="$OBJC" am_compiler_list='gcc3 gcc'],
+      [$1], [OBJCXX], [depcc="$OBJCXX" am_compiler_list='gcc3 gcc'],
+      [$1], [UPC],  [depcc="$UPC"  am_compiler_list=],
+      [$1], [GCJ],  [depcc="$GCJ"  am_compiler_list='gcc3 gcc'],
+                    [depcc="$$1"   am_compiler_list=])
+
+AC_CACHE_CHECK([dependency style of $depcc],
+               [am_cv_$1_dependencies_compiler_type],
+[if test -z "$AMDEP_TRUE" && test -f "$am_depcomp"; then
+  # We make a subdir and do the tests there.  Otherwise we can end up
+  # making bogus files that we don't know about and never remove.  For
+  # instance it was reported that on HP-UX the gcc test will end up
+  # making a dummy file named 'D' -- because '-MD' means "put the output
+  # in D".
+  rm -rf conftest.dir
+  mkdir conftest.dir
+  # Copy depcomp to subdir because otherwise we won't find it if we're
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+  cp "$am_depcomp" conftest.dir
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+  # We will build objects and dependencies in a subdirectory because
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+  # side effect of compilation, but ICC will put the dependencies in
+  # the current directory while Tru64 will put them in the object
+  # directory.
+  mkdir sub
+
+  am_cv_$1_dependencies_compiler_type=none
+  if test "$am_compiler_list" = ""; then
+     am_compiler_list=`sed -n ['s/^#*\([a-zA-Z0-9]*\))$/\1/p'] < ./depcomp`
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+  am__universal=false
+  m4_case([$1], [CC],
+    [case " $depcc " in #(
+     *\ -arch\ *\ -arch\ *) am__universal=true ;;
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+    [CXX],
+    [case " $depcc " in #(
+     *\ -arch\ *\ -arch\ *) am__universal=true ;;
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+
+  for depmode in $am_compiler_list; do
+    # Setup a source with many dependencies, because some compilers
+    # like to wrap large dependency lists on column 80 (with \), and
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+    #
+    # We need to recreate these files for each test, as the compiler may
+    # overwrite some of them when testing with obscure command lines.
+    # This happens at least with the AIX C compiler.
+    : > sub/conftest.c
+    for i in 1 2 3 4 5 6; do
+      echo '#include "conftst'$i'.h"' >> sub/conftest.c
+      # Using ": > sub/conftst$i.h" creates only sub/conftst1.h with
+      # Solaris 10 /bin/sh.
+      echo '/* dummy */' > sub/conftst$i.h
+    done
+    echo "${am__include} ${am__quote}sub/conftest.Po${am__quote}" > confmf
+
+    # We check with '-c' and '-o' for the sake of the "dashmstdout"
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+    # handle '-M -o', and we need to detect this.  Also, some Intel
+    # versions had trouble with output in subdirs.
+    am__obj=sub/conftest.${OBJEXT-o}
+    am__minus_obj="-o $am__obj"
+    case $depmode in
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+      test "$am__universal" = false || continue
+      ;;
+    nosideeffect)
+      # After this tag, mechanisms are not by side-effect, so they'll
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+      if test "x$enable_dependency_tracking" = xyes; then
+	continue
+      else
+	break
+      fi
+      ;;
+    msvc7 | msvc7msys | msvisualcpp | msvcmsys)
+      # This compiler won't grok '-c -o', but also, the minuso test has
+      # not run yet.  These depmodes are late enough in the game, and
+      # so weak that their functioning should not be impacted.
+      am__obj=conftest.${OBJEXT-o}
+      am__minus_obj=
+      ;;
+    none) break ;;
+    esac
+    if depmode=$depmode \
+       source=sub/conftest.c object=$am__obj \
+       depfile=sub/conftest.Po tmpdepfile=sub/conftest.TPo \
+       $SHELL ./depcomp $depcc -c $am__minus_obj sub/conftest.c \
+         >/dev/null 2>conftest.err &&
+       grep sub/conftst1.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep sub/conftst6.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep $am__obj sub/conftest.Po > /dev/null 2>&1 &&
+       ${MAKE-make} -s -f confmf > /dev/null 2>&1; then
+      # icc doesn't choke on unknown options, it will just issue warnings
+      # or remarks (even with -Werror).  So we grep stderr for any message
+      # that says an option was ignored or not supported.
+      # When given -MP, icc 7.0 and 7.1 complain thusly:
+      #   icc: Command line warning: ignoring option '-M'; no argument required
+      # The diagnosis changed in icc 8.0:
+      #   icc: Command line remark: option '-MP' not supported
+      if (grep 'ignoring option' conftest.err ||
+          grep 'not supported' conftest.err) >/dev/null 2>&1; then :; else
+        am_cv_$1_dependencies_compiler_type=$depmode
+        break
+      fi
+    fi
+  done
+
+  cd ..
+  rm -rf conftest.dir
+else
+  am_cv_$1_dependencies_compiler_type=none
+fi
+])
+AC_SUBST([$1DEPMODE], [depmode=$am_cv_$1_dependencies_compiler_type])
+AM_CONDITIONAL([am__fastdep$1], [
+  test "x$enable_dependency_tracking" != xno \
+  && test "$am_cv_$1_dependencies_compiler_type" = gcc3])
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+
+
+# AM_SET_DEPDIR
+# -------------
+# Choose a directory name for dependency files.
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+AC_DEFUN([AM_SET_DEPDIR],
+[AC_REQUIRE([AM_SET_LEADING_DOT])dnl
+AC_SUBST([DEPDIR], ["${am__leading_dot}deps"])dnl
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+
+
+# AM_DEP_TRACK
+# ------------
+AC_DEFUN([AM_DEP_TRACK],
+[AC_ARG_ENABLE([dependency-tracking], [dnl
+AS_HELP_STRING(
+  [--enable-dependency-tracking],
+  [do not reject slow dependency extractors])
+AS_HELP_STRING(
+  [--disable-dependency-tracking],
+  [speeds up one-time build])])
+if test "x$enable_dependency_tracking" != xno; then
+  am_depcomp="$ac_aux_dir/depcomp"
+  AMDEPBACKSLASH='\'
+  am__nodep='_no'
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+AM_CONDITIONAL([AMDEP], [test "x$enable_dependency_tracking" != xno])
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+_AM_SUBST_NOTMAKE([AMDEPBACKSLASH])dnl
+AC_SUBST([am__nodep])dnl
+_AM_SUBST_NOTMAKE([am__nodep])dnl
+])
+
+# Generate code to set up dependency tracking.              -*- Autoconf -*-
+
+# Copyright (C) 1999-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_OUTPUT_DEPENDENCY_COMMANDS
+# ------------------------------
+AC_DEFUN([_AM_OUTPUT_DEPENDENCY_COMMANDS],
+[{
+  # Older Autoconf quotes --file arguments for eval, but not when files
+  # are listed without --file.  Let's play safe and only enable the eval
+  # if we detect the quoting.
+  # TODO: see whether this extra hack can be removed once we start
+  # requiring Autoconf 2.70 or later.
+  AS_CASE([$CONFIG_FILES],
+          [*\'*], [eval set x "$CONFIG_FILES"],
+          [*], [set x $CONFIG_FILES])
+  shift
+  # Used to flag and report bootstrapping failures.
+  am_rc=0
+  for am_mf
+  do
+    # Strip MF so we end up with the name of the file.
+    am_mf=`AS_ECHO(["$am_mf"]) | sed -e 's/:.*$//'`
+    # Check whether this is an Automake generated Makefile which includes
+    # dependency-tracking related rules and includes.
+    # Grep'ing the whole file directly is not great: AIX grep has a line
+    # limit of 2048, but all sed's we know have understand at least 4000.
+    sed -n 's,^am--depfiles:.*,X,p' "$am_mf" | grep X >/dev/null 2>&1 \
+      || continue
+    am_dirpart=`AS_DIRNAME(["$am_mf"])`
+    am_filepart=`AS_BASENAME(["$am_mf"])`
+    AM_RUN_LOG([cd "$am_dirpart" \
+      && sed -e '/# am--include-marker/d' "$am_filepart" \
+        | $MAKE -f - am--depfiles]) || am_rc=$?
+  done
+  if test $am_rc -ne 0; then
+    AC_MSG_FAILURE([Something went wrong bootstrapping makefile fragments
+    for automatic dependency tracking.  If GNU make was not used, consider
+    re-running the configure script with MAKE="gmake" (or whatever is
+    necessary).  You can also try re-running configure with the
+    '--disable-dependency-tracking' option to at least be able to build
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+  fi
+  AS_UNSET([am_dirpart])
+  AS_UNSET([am_filepart])
+  AS_UNSET([am_mf])
+  AS_UNSET([am_rc])
+  rm -f conftest-deps.mk
+}
+])# _AM_OUTPUT_DEPENDENCY_COMMANDS
+
+
+# AM_OUTPUT_DEPENDENCY_COMMANDS
+# -----------------------------
+# This macro should only be invoked once -- use via AC_REQUIRE.
+#
+# This code is only required when automatic dependency tracking is enabled.
+# This creates each '.Po' and '.Plo' makefile fragment that we'll need in
+# order to bootstrap the dependency handling code.
+AC_DEFUN([AM_OUTPUT_DEPENDENCY_COMMANDS],
+[AC_CONFIG_COMMANDS([depfiles],
+     [test x"$AMDEP_TRUE" != x"" || _AM_OUTPUT_DEPENDENCY_COMMANDS],
+     [AMDEP_TRUE="$AMDEP_TRUE" MAKE="${MAKE-make}"])])
+
+# Do all the work for Automake.                             -*- Autoconf -*-
+
+# Copyright (C) 1996-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# This macro actually does too much.  Some checks are only needed if
+# your package does certain things.  But this isn't really a big deal.
+
+dnl Redefine AC_PROG_CC to automatically invoke _AM_PROG_CC_C_O.
+m4_define([AC_PROG_CC],
+m4_defn([AC_PROG_CC])
+[_AM_PROG_CC_C_O
+])
+
+# AM_INIT_AUTOMAKE(PACKAGE, VERSION, [NO-DEFINE])
+# AM_INIT_AUTOMAKE([OPTIONS])
+# -----------------------------------------------
+# The call with PACKAGE and VERSION arguments is the old style
+# call (pre autoconf-2.50), which is being phased out.  PACKAGE
+# and VERSION should now be passed to AC_INIT and removed from
+# the call to AM_INIT_AUTOMAKE.
+# We support both call styles for the transition.  After
+# the next Automake release, Autoconf can make the AC_INIT
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+AC_DEFUN([AM_INIT_AUTOMAKE],
+[AC_PREREQ([2.65])dnl
+m4_ifdef([_$0_ALREADY_INIT],
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+  [m4_define([_$0_ALREADY_INIT], m4_expansion_stack)])dnl
+dnl Autoconf wants to disallow AM_ names.  We explicitly allow
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+AC_REQUIRE([AM_SET_CURRENT_AUTOMAKE_VERSION])dnl
+AC_REQUIRE([AC_PROG_INSTALL])dnl
+if test "`cd $srcdir && pwd`" != "`pwd`"; then
+  # Use -I$(srcdir) only when $(srcdir) != ., so that make's output
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+  AC_SUBST([am__isrc], [' -I$(srcdir)'])_AM_SUBST_NOTMAKE([am__isrc])dnl
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+  if test -f $srcdir/config.status; then
+    AC_MSG_ERROR([source directory already configured; run "make distclean" there first])
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+fi
+
+# test whether we have cygpath
+if test -z "$CYGPATH_W"; then
+  if (cygpath --version) >/dev/null 2>/dev/null; then
+    CYGPATH_W='cygpath -w'
+  else
+    CYGPATH_W=echo
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+AC_SUBST([CYGPATH_W])
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+# Define the identity of the package.
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+m4_ifval([$3], [_AM_SET_OPTION([no-define])])dnl
+ AC_SUBST([PACKAGE], [$1])dnl
+ AC_SUBST([VERSION], [$2])],
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+dnl Diagnose old-style AC_INIT with new-style AM_AUTOMAKE_INIT.
+m4_if(
+  m4_ifset([AC_PACKAGE_NAME], [ok]):m4_ifset([AC_PACKAGE_VERSION], [ok]),
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+  [m4_fatal([AC_INIT should be called with package and version arguments])])dnl
+ AC_SUBST([PACKAGE], ['AC_PACKAGE_TARNAME'])dnl
+ AC_SUBST([VERSION], ['AC_PACKAGE_VERSION'])])dnl
+
+_AM_IF_OPTION([no-define],,
+[AC_DEFINE_UNQUOTED([PACKAGE], ["$PACKAGE"], [Name of package])
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+# Some tools Automake needs.
+AC_REQUIRE([AM_SANITY_CHECK])dnl
+AC_REQUIRE([AC_ARG_PROGRAM])dnl
+AM_MISSING_PROG([ACLOCAL], [aclocal-${am__api_version}])
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+AM_MISSING_PROG([AUTOMAKE], [automake-${am__api_version}])
+AM_MISSING_PROG([AUTOHEADER], [autoheader])
+AM_MISSING_PROG([MAKEINFO], [makeinfo])
+AC_REQUIRE([AM_PROG_INSTALL_SH])dnl
+AC_REQUIRE([AM_PROG_INSTALL_STRIP])dnl
+AC_REQUIRE([AC_PROG_MKDIR_P])dnl
+# For better backward compatibility.  To be removed once Automake 1.9.x
+# dies out for good.  For more background, see:
+# <https://lists.gnu.org/archive/html/automake/2012-07/msg00001.html>
+# <https://lists.gnu.org/archive/html/automake/2012-07/msg00014.html>
+AC_SUBST([mkdir_p], ['$(MKDIR_P)'])
+# We need awk for the "check" target (and possibly the TAP driver).  The
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+AC_REQUIRE([AC_PROG_AWK])dnl
+AC_REQUIRE([AC_PROG_MAKE_SET])dnl
+AC_REQUIRE([AM_SET_LEADING_DOT])dnl
+_AM_IF_OPTION([tar-ustar], [_AM_PROG_TAR([ustar])],
+	      [_AM_IF_OPTION([tar-pax], [_AM_PROG_TAR([pax])],
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+_AM_IF_OPTION([no-dependencies],,
+[AC_PROVIDE_IFELSE([AC_PROG_CC],
+		  [_AM_DEPENDENCIES([CC])],
+		  [m4_define([AC_PROG_CC],
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+AC_PROVIDE_IFELSE([AC_PROG_CXX],
+		  [_AM_DEPENDENCIES([CXX])],
+		  [m4_define([AC_PROG_CXX],
+			     m4_defn([AC_PROG_CXX])[_AM_DEPENDENCIES([CXX])])])dnl
+AC_PROVIDE_IFELSE([AC_PROG_OBJC],
+		  [_AM_DEPENDENCIES([OBJC])],
+		  [m4_define([AC_PROG_OBJC],
+			     m4_defn([AC_PROG_OBJC])[_AM_DEPENDENCIES([OBJC])])])dnl
+AC_PROVIDE_IFELSE([AC_PROG_OBJCXX],
+		  [_AM_DEPENDENCIES([OBJCXX])],
+		  [m4_define([AC_PROG_OBJCXX],
+			     m4_defn([AC_PROG_OBJCXX])[_AM_DEPENDENCIES([OBJCXX])])])dnl
+])
+# Variables for tags utilities; see am/tags.am
+if test -z "$CTAGS"; then
+  CTAGS=ctags
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+AC_SUBST([CTAGS])
+if test -z "$ETAGS"; then
+  ETAGS=etags
+fi
+AC_SUBST([ETAGS])
+if test -z "$CSCOPE"; then
+  CSCOPE=cscope
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+AC_REQUIRE([AM_SILENT_RULES])dnl
+dnl The testsuite driver may need to know about EXEEXT, so add the
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+[m4_provide_if([_AM_COMPILER_EXEEXT],
+  [AM_CONDITIONAL([am__EXEEXT], [test -n "$EXEEXT"])])])dnl
+
+# POSIX will say in a future version that running "rm -f" with no argument
+# is OK; and we want to be able to make that assumption in our Makefile
+# recipes.  So use an aggressive probe to check that the usage we want is
+# actually supported "in the wild" to an acceptable degree.
+# See automake bug#10828.
+# To make any issue more visible, cause the running configure to be aborted
+# by default if the 'rm' program in use doesn't match our expectations; the
+# user can still override this though.
+if rm -f && rm -fr && rm -rf; then : OK; else
+  cat >&2 <<'END'
+Oops!
+
+Your 'rm' program seems unable to run without file operands specified
+on the command line, even when the '-f' option is present.  This is contrary
+to the behaviour of most rm programs out there, and not conforming with
+the upcoming POSIX standard: <http://austingroupbugs.net/view.php?id=542>
+
+Please tell bug-automake@gnu.org about your system, including the value
+of your $PATH and any error possibly output before this message.  This
+can help us improve future automake versions.
+
+END
+  if test x"$ACCEPT_INFERIOR_RM_PROGRAM" = x"yes"; then
+    echo 'Configuration will proceed anyway, since you have set the' >&2
+    echo 'ACCEPT_INFERIOR_RM_PROGRAM variable to "yes"' >&2
+    echo >&2
+  else
+    cat >&2 <<'END'
+Aborting the configuration process, to ensure you take notice of the issue.
+
+You can download and install GNU coreutils to get an 'rm' implementation
+that behaves properly: <https://www.gnu.org/software/coreutils/>.
+
+If you want to complete the configuration process using your problematic
+'rm' anyway, export the environment variable ACCEPT_INFERIOR_RM_PROGRAM
+to "yes", and re-run configure.
+
+END
+    AC_MSG_ERROR([Your 'rm' program is bad, sorry.])
+  fi
+fi
+dnl The trailing newline in this macro's definition is deliberate, for
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+])
+
+dnl Hook into '_AC_COMPILER_EXEEXT' early to learn its expansion.  Do not
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+# Copyright (C) 2001-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_PROG_INSTALL_SH
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+AC_DEFUN([AM_PROG_INSTALL_SH],
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+fi
+AC_SUBST([install_sh])])
+
+# Copyright (C) 2003-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Check whether the underlying file-system supports filenames
+# with a leading dot.  For instance MS-DOS doesn't.
+AC_DEFUN([AM_SET_LEADING_DOT],
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+  am__leading_dot=_
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+rmdir .tst 2>/dev/null
+AC_SUBST([am__leading_dot])])
+
+# Add --enable-maintainer-mode option to configure.         -*- Autoconf -*-
+# From Jim Meyering
+
+# Copyright (C) 1996-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_MAINTAINER_MODE([DEFAULT-MODE])
+# ----------------------------------
+# Control maintainer-specific portions of Makefiles.
+# Default is to disable them, unless 'enable' is passed literally.
+# For symmetry, 'disable' may be passed as well.  Anyway, the user
+# can override the default with the --enable/--disable switch.
+AC_DEFUN([AM_MAINTAINER_MODE],
+[m4_case(m4_default([$1], [disable]),
+       [enable], [m4_define([am_maintainer_other], [disable])],
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+       [m4_define([am_maintainer_other], [enable])
+        m4_warn([syntax], [unexpected argument to AM@&t@_MAINTAINER_MODE: $1])])
+AC_MSG_CHECKING([whether to enable maintainer-specific portions of Makefiles])
+  dnl maintainer-mode's default is 'disable' unless 'enable' is passed
+  AC_ARG_ENABLE([maintainer-mode],
+    [AS_HELP_STRING([--]am_maintainer_other[-maintainer-mode],
+      am_maintainer_other[ make rules and dependencies not useful
+      (and sometimes confusing) to the casual installer])],
+    [USE_MAINTAINER_MODE=$enableval],
+    [USE_MAINTAINER_MODE=]m4_if(am_maintainer_other, [enable], [no], [yes]))
+  AC_MSG_RESULT([$USE_MAINTAINER_MODE])
+  AM_CONDITIONAL([MAINTAINER_MODE], [test $USE_MAINTAINER_MODE = yes])
+  MAINT=$MAINTAINER_MODE_TRUE
+  AC_SUBST([MAINT])dnl
+]
+)
+
+# Check to see how 'make' treats includes.	            -*- Autoconf -*-
+
+# Copyright (C) 2001-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_MAKE_INCLUDE()
+# -----------------
+# Check whether make has an 'include' directive that can support all
+# the idioms we need for our automatic dependency tracking code.
+AC_DEFUN([AM_MAKE_INCLUDE],
+[AC_MSG_CHECKING([whether ${MAKE-make} supports the include directive])
+cat > confinc.mk << 'END'
+am__doit:
+	@echo this is the am__doit target >confinc.out
+.PHONY: am__doit
+END
+am__include="#"
+am__quote=
+# BSD make does it like this.
+echo '.include "confinc.mk" # ignored' > confmf.BSD
+# Other make implementations (GNU, Solaris 10, AIX) do it like this.
+echo 'include confinc.mk # ignored' > confmf.GNU
+_am_result=no
+for s in GNU BSD; do
+  AM_RUN_LOG([${MAKE-make} -f confmf.$s && cat confinc.out])
+  AS_CASE([$?:`cat confinc.out 2>/dev/null`],
+      ['0:this is the am__doit target'],
+      [AS_CASE([$s],
+          [BSD], [am__include='.include' am__quote='"'],
+          [am__include='include' am__quote=''])])
+  if test "$am__include" != "#"; then
+    _am_result="yes ($s style)"
+    break
+  fi
+done
+rm -f confinc.* confmf.*
+AC_MSG_RESULT([${_am_result}])
+AC_SUBST([am__include])])
+AC_SUBST([am__quote])])
+
+# Fake the existence of programs that GNU maintainers use.  -*- Autoconf -*-
+
+# Copyright (C) 1997-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_MISSING_PROG(NAME, PROGRAM)
+# ------------------------------
+AC_DEFUN([AM_MISSING_PROG],
+[AC_REQUIRE([AM_MISSING_HAS_RUN])
+$1=${$1-"${am_missing_run}$2"}
+AC_SUBST($1)])
+
+# AM_MISSING_HAS_RUN
+# ------------------
+# Define MISSING if not defined so far and test if it is modern enough.
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+AC_DEFUN([AM_MISSING_HAS_RUN],
+[AC_REQUIRE([AM_AUX_DIR_EXPAND])dnl
+AC_REQUIRE_AUX_FILE([missing])dnl
+if test x"${MISSING+set}" != xset; then
+  MISSING="\${SHELL} '$am_aux_dir/missing'"
+fi
+# Use eval to expand $SHELL
+if eval "$MISSING --is-lightweight"; then
+  am_missing_run="$MISSING "
+else
+  am_missing_run=
+  AC_MSG_WARN(['missing' script is too old or missing])
+fi
+])
+
+# Helper functions for option handling.                     -*- Autoconf -*-
+
+# Copyright (C) 2001-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_MANGLE_OPTION(NAME)
+# -----------------------
+AC_DEFUN([_AM_MANGLE_OPTION],
+[[_AM_OPTION_]m4_bpatsubst($1, [[^a-zA-Z0-9_]], [_])])
+
+# _AM_SET_OPTION(NAME)
+# --------------------
+# Set option NAME.  Presently that only means defining a flag for this option.
+AC_DEFUN([_AM_SET_OPTION],
+[m4_define(_AM_MANGLE_OPTION([$1]), [1])])
+
+# _AM_SET_OPTIONS(OPTIONS)
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+# OPTIONS is a space-separated list of Automake options.
+AC_DEFUN([_AM_SET_OPTIONS],
+[m4_foreach_w([_AM_Option], [$1], [_AM_SET_OPTION(_AM_Option)])])
+
+# _AM_IF_OPTION(OPTION, IF-SET, [IF-NOT-SET])
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+# Execute IF-SET if OPTION is set, IF-NOT-SET otherwise.
+AC_DEFUN([_AM_IF_OPTION],
+[m4_ifset(_AM_MANGLE_OPTION([$1]), [$2], [$3])])
+
+# Copyright (C) 1999-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_PROG_CC_C_O
+# ---------------
+# Like AC_PROG_CC_C_O, but changed for automake.  We rewrite AC_PROG_CC
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+[AC_REQUIRE([AM_AUX_DIR_EXPAND])dnl
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+AC_LANG_PUSH([C])dnl
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+  [whether $CC understands -c and -o together],
+  [am_cv_prog_cc_c_o],
+  [AC_LANG_CONFTEST([AC_LANG_PROGRAM([])])
+  # Make sure it works both with $CC and with simple cc.
+  # Following AC_PROG_CC_C_O, we do the test twice because some
+  # compilers refuse to overwrite an existing .o file with -o,
+  # though they will create one.
+  am_cv_prog_cc_c_o=yes
+  for am_i in 1 2; do
+    if AM_RUN_LOG([$CC -c conftest.$ac_ext -o conftest2.$ac_objext]) \
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+      am_cv_prog_cc_c_o=no
+      break
+    fi
+  done
+  rm -f core conftest*
+  unset am_i])
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+   # Losing compiler, so override with the script.
+   # FIXME: It is wrong to rewrite CC.
+   # But if we don't then we get into trouble of one sort or another.
+   # A longer-term fix would be to have automake use am__CC in this case,
+   # and then we could set am__CC="\$(top_srcdir)/compile \$(CC)"
+   CC="$am_aux_dir/compile $CC"
+fi
+AC_LANG_POP([C])])
+
+# For backward compatibility.
+AC_DEFUN_ONCE([AM_PROG_CC_C_O], [AC_REQUIRE([AC_PROG_CC])])
+
+# Copyright (C) 2001-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_RUN_LOG(COMMAND)
+# -------------------
+# Run COMMAND, save the exit status in ac_status, and log it.
+# (This has been adapted from Autoconf's _AC_RUN_LOG macro.)
+AC_DEFUN([AM_RUN_LOG],
+[{ echo "$as_me:$LINENO: $1" >&AS_MESSAGE_LOG_FD
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+   echo "$as_me:$LINENO: \$? = $ac_status" >&AS_MESSAGE_LOG_FD
+   (exit $ac_status); }])
+
+# Check to make sure that the build environment is sane.    -*- Autoconf -*-
+
+# Copyright (C) 1996-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_SANITY_CHECK
+# ---------------
+AC_DEFUN([AM_SANITY_CHECK],
+[AC_MSG_CHECKING([whether build environment is sane])
+# Reject unsafe characters in $srcdir or the absolute working directory
+# name.  Accept space and tab only in the latter.
+am_lf='
+'
+case `pwd` in
+  *[[\\\"\#\$\&\'\`$am_lf]]*)
+    AC_MSG_ERROR([unsafe absolute working directory name]);;
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+case $srcdir in
+  *[[\\\"\#\$\&\'\`$am_lf\ \	]]*)
+    AC_MSG_ERROR([unsafe srcdir value: '$srcdir']);;
+esac
+
+# Do 'set' in a subshell so we don't clobber the current shell's
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+# symlink; some systems play weird games with the mod time of symlinks
+# (eg FreeBSD returns the mod time of the symlink's containing
+# directory).
+if (
+   am_has_slept=no
+   for am_try in 1 2; do
+     echo "timestamp, slept: $am_has_slept" > conftest.file
+     set X `ls -Lt "$srcdir/configure" conftest.file 2> /dev/null`
+     if test "$[*]" = "X"; then
+	# -L didn't work.
+	set X `ls -t "$srcdir/configure" conftest.file`
+     fi
+     if test "$[*]" != "X $srcdir/configure conftest.file" \
+	&& test "$[*]" != "X conftest.file $srcdir/configure"; then
+
+	# If neither matched, then we have a broken ls.  This can happen
+	# if, for instance, CONFIG_SHELL is bash and it inherits a
+	# broken ls alias from the environment.  This has actually
+	# happened.  Such a system could not be considered "sane".
+	AC_MSG_ERROR([ls -t appears to fail.  Make sure there is not a broken
+  alias in your environment])
+     fi
+     if test "$[2]" = conftest.file || test $am_try -eq 2; then
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+     fi
+     # Just in case.
+     sleep 1
+     am_has_slept=yes
+   done
+   test "$[2]" = conftest.file
+   )
+then
+   # Ok.
+   :
+else
+   AC_MSG_ERROR([newly created file is older than distributed files!
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+fi
+AC_MSG_RESULT([yes])
+# If we didn't sleep, we still need to ensure time stamps of config.status and
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+AC_CONFIG_COMMANDS_PRE(
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+     wait $am_sleep_pid 2>/dev/null
+   fi
+   AC_MSG_RESULT([done])])
+rm -f conftest.file
+])
+
+# Copyright (C) 2009-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_SILENT_RULES([DEFAULT])
+# --------------------------
+# Enable less verbose build rules; with the default set to DEFAULT
+# ("yes" being less verbose, "no" or empty being verbose).
+AC_DEFUN([AM_SILENT_RULES],
+[AC_ARG_ENABLE([silent-rules], [dnl
+AS_HELP_STRING(
+  [--enable-silent-rules],
+  [less verbose build output (undo: "make V=1")])
+AS_HELP_STRING(
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+  [verbose build output (undo: "make V=0")])dnl
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+  yes) AM_DEFAULT_VERBOSITY=0;;
+   no) AM_DEFAULT_VERBOSITY=1;;
+    *) AM_DEFAULT_VERBOSITY=m4_if([$1], [yes], [0], [1]);;
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+dnl
+dnl A few 'make' implementations (e.g., NonStop OS and NextStep)
+dnl do not support nested variable expansions.
+dnl See automake bug#9928 and bug#10237.
+am_make=${MAKE-make}
+AC_CACHE_CHECK([whether $am_make supports nested variables],
+   [am_cv_make_support_nested_variables],
+   [if AS_ECHO([['TRUE=$(BAR$(V))
+BAR0=false
+BAR1=true
+V=1
+am__doit:
+	@$(TRUE)
+.PHONY: am__doit']]) | $am_make -f - >/dev/null 2>&1; then
+  am_cv_make_support_nested_variables=yes
+else
+  am_cv_make_support_nested_variables=no
+fi])
+if test $am_cv_make_support_nested_variables = yes; then
+  dnl Using '$V' instead of '$(V)' breaks IRIX make.
+  AM_V='$(V)'
+  AM_DEFAULT_V='$(AM_DEFAULT_VERBOSITY)'
+else
+  AM_V=$AM_DEFAULT_VERBOSITY
+  AM_DEFAULT_V=$AM_DEFAULT_VERBOSITY
+fi
+AC_SUBST([AM_V])dnl
+AM_SUBST_NOTMAKE([AM_V])dnl
+AC_SUBST([AM_DEFAULT_V])dnl
+AM_SUBST_NOTMAKE([AM_DEFAULT_V])dnl
+AC_SUBST([AM_DEFAULT_VERBOSITY])dnl
+AM_BACKSLASH='\'
+AC_SUBST([AM_BACKSLASH])dnl
+_AM_SUBST_NOTMAKE([AM_BACKSLASH])dnl
+])
+
+# Copyright (C) 2001-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# AM_PROG_INSTALL_STRIP
+# ---------------------
+# One issue with vendor 'install' (even GNU) is that you can't
+# specify the program used to strip binaries.  This is especially
+# annoying in cross-compiling environments, where the build's strip
+# is unlikely to handle the host's binaries.
+# Fortunately install-sh will honor a STRIPPROG variable, so we
+# always use install-sh in "make install-strip", and initialize
+# STRIPPROG with the value of the STRIP variable (set by the user).
+AC_DEFUN([AM_PROG_INSTALL_STRIP],
+[AC_REQUIRE([AM_PROG_INSTALL_SH])dnl
+# Installed binaries are usually stripped using 'strip' when the user
+# run "make install-strip".  However 'strip' might not be the right
+# tool to use in cross-compilation environments, therefore Automake
+# will honor the 'STRIP' environment variable to overrule this program.
+dnl Don't test for $cross_compiling = yes, because it might be 'maybe'.
+if test "$cross_compiling" != no; then
+  AC_CHECK_TOOL([STRIP], [strip], :)
+fi
+INSTALL_STRIP_PROGRAM="\$(install_sh) -c -s"
+AC_SUBST([INSTALL_STRIP_PROGRAM])])
+
+# Copyright (C) 2006-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_SUBST_NOTMAKE(VARIABLE)
+# ---------------------------
+# Prevent Automake from outputting VARIABLE = @VARIABLE@ in Makefile.in.
+# This macro is traced by Automake.
+AC_DEFUN([_AM_SUBST_NOTMAKE])
+
+# AM_SUBST_NOTMAKE(VARIABLE)
+# --------------------------
+# Public sister of _AM_SUBST_NOTMAKE.
+AC_DEFUN([AM_SUBST_NOTMAKE], [_AM_SUBST_NOTMAKE($@)])
+
+# Check how to create a tarball.                            -*- Autoconf -*-
+
+# Copyright (C) 2004-2021 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# _AM_PROG_TAR(FORMAT)
+# --------------------
+# Check how to create a tarball in format FORMAT.
+# FORMAT should be one of 'v7', 'ustar', or 'pax'.
+#
+# Substitute a variable $(am__tar) that is a command
+# writing to stdout a FORMAT-tarball containing the directory
+# $tardir.
+#     tardir=directory && $(am__tar) > result.tar
+#
+# Substitute a variable $(am__untar) that extract such
+# a tarball read from stdin.
+#     $(am__untar) < result.tar
+#
+AC_DEFUN([_AM_PROG_TAR],
+[# Always define AMTAR for backward compatibility.  Yes, it's still used
+# in the wild :-(  We should find a proper way to deprecate it ...
+AC_SUBST([AMTAR], ['$${TAR-tar}'])
+
+# We'll loop over all known methods to create a tar archive until one works.
+_am_tools='gnutar m4_if([$1], [ustar], [plaintar]) pax cpio none'
+
+m4_if([$1], [v7],
+  [am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'],
+
+  [m4_case([$1],
+    [ustar],
+     [# The POSIX 1988 'ustar' format is defined with fixed-size fields.
+      # There is notably a 21 bits limit for the UID and the GID.  In fact,
+      # the 'pax' utility can hang on bigger UID/GID (see automake bug#8343
+      # and bug#13588).
+      am_max_uid=2097151 # 2^21 - 1
+      am_max_gid=$am_max_uid
+      # The $UID and $GID variables are not portable, so we need to resort
+      # to the POSIX-mandated id(1) utility.  Errors in the 'id' calls
+      # below are definitely unexpected, so allow the users to see them
+      # (that is, avoid stderr redirection).
+      am_uid=`id -u || echo unknown`
+      am_gid=`id -g || echo unknown`
+      AC_MSG_CHECKING([whether UID '$am_uid' is supported by ustar format])
+      if test $am_uid -le $am_max_uid; then
+         AC_MSG_RESULT([yes])
+      else
+         AC_MSG_RESULT([no])
+         _am_tools=none
+      fi
+      AC_MSG_CHECKING([whether GID '$am_gid' is supported by ustar format])
+      if test $am_gid -le $am_max_gid; then
+         AC_MSG_RESULT([yes])
+      else
+        AC_MSG_RESULT([no])
+        _am_tools=none
+      fi],
+
+  [pax],
+    [],
+
+  [m4_fatal([Unknown tar format])])
+
+  AC_MSG_CHECKING([how to create a $1 tar archive])
+
+  # Go ahead even if we have the value already cached.  We do so because we
+  # need to set the values for the 'am__tar' and 'am__untar' variables.
+  _am_tools=${am_cv_prog_tar_$1-$_am_tools}
+
+  for _am_tool in $_am_tools; do
+    case $_am_tool in
+    gnutar)
+      for _am_tar in tar gnutar gtar; do
+        AM_RUN_LOG([$_am_tar --version]) && break
+      done
+      am__tar="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$$tardir"'
+      am__tar_="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$tardir"'
+      am__untar="$_am_tar -xf -"
+      ;;
+    plaintar)
+      # Must skip GNU tar: if it does not support --format= it doesn't create
+      # ustar tarball either.
+      (tar --version) >/dev/null 2>&1 && continue
+      am__tar='tar chf - "$$tardir"'
+      am__tar_='tar chf - "$tardir"'
+      am__untar='tar xf -'
+      ;;
+    pax)
+      am__tar='pax -L -x $1 -w "$$tardir"'
+      am__tar_='pax -L -x $1 -w "$tardir"'
+      am__untar='pax -r'
+      ;;
+    cpio)
+      am__tar='find "$$tardir" -print | cpio -o -H $1 -L'
+      am__tar_='find "$tardir" -print | cpio -o -H $1 -L'
+      am__untar='cpio -i -H $1 -d'
+      ;;
+    none)
+      am__tar=false
+      am__tar_=false
+      am__untar=false
+      ;;
+    esac
+
+    # If the value was cached, stop now.  We just wanted to have am__tar
+    # and am__untar set.
+    test -n "${am_cv_prog_tar_$1}" && break
+
+    # tar/untar a dummy directory, and stop if the command works.
+    rm -rf conftest.dir
+    mkdir conftest.dir
+    echo GrepMe > conftest.dir/file
+    AM_RUN_LOG([tardir=conftest.dir && eval $am__tar_ >conftest.tar])
+    rm -rf conftest.dir
+    if test -s conftest.tar; then
+      AM_RUN_LOG([$am__untar <conftest.tar])
+      AM_RUN_LOG([cat conftest.dir/file])
+      grep GrepMe conftest.dir/file >/dev/null 2>&1 && break
+    fi
+  done
+  rm -rf conftest.dir
+
+  AC_CACHE_VAL([am_cv_prog_tar_$1], [am_cv_prog_tar_$1=$_am_tool])
+  AC_MSG_RESULT([$am_cv_prog_tar_$1])])
+
+AC_SUBST([am__tar])
+AC_SUBST([am__untar])
+]) # _AM_PROG_TAR
+
+m4_include([scripts/autoconf/libtool.m4])
+m4_include([scripts/autoconf/ltoptions.m4])
+m4_include([scripts/autoconf/ltsugar.m4])
+m4_include([scripts/autoconf/ltversion.m4])
+m4_include([scripts/autoconf/lt~obsolete.m4])
Index: /trunk/src/libs/libpng-1.6.45/arm/arm_init.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/arm/arm_init.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/arm/arm_init.c	(revision 107811)
@@ -0,0 +1,139 @@
+
+/* arm_init.c - NEON optimised filter functions
+ *
+ * Copyright (c) 2018-2022 Cosmin Truta
+ * Copyright (c) 2014,2016 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* This module requires POSIX 1003.1 functions. */
+#define _POSIX_SOURCE 1
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_ARM_NEON_OPT > 0
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
+/* WARNING: it is strongly recommended that you do not build libpng with
+ * run-time checks for CPU features if at all possible.  In the case of the ARM
+ * NEON instructions there is no processor-specific way of detecting the
+ * presence of the required support, therefore run-time detection is extremely
+ * OS specific.
+ *
+ * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing
+ * a fragment of C source code which defines the png_have_neon function.  There
+ * are a number of implementations in contrib/arm-neon, but the only one that
+ * has partial support is contrib/arm-neon/linux.c - a generic Linux
+ * implementation which reads /proc/cpufino.
+ */
+#include <signal.h> /* for sig_atomic_t */
+
+#ifndef PNG_ARM_NEON_FILE
+#  if defined(__aarch64__) || defined(_M_ARM64)
+     /* ARM Neon is expected to be unconditionally available on ARM64. */
+#    error "PNG_ARM_NEON_CHECK_SUPPORTED must not be defined on ARM64"
+#  elif defined(__ARM_NEON__) || defined(__ARM_NEON)
+     /* ARM Neon is expected to be available on the target CPU architecture. */
+#    error "PNG_ARM_NEON_CHECK_SUPPORTED must not be defined on this CPU arch"
+#  elif defined(__linux__)
+#    define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c"
+#  else
+#    error "No support for run-time ARM Neon checking; use compile-time options"
+#  endif
+#endif
+
+static int png_have_neon(png_structp png_ptr);
+#ifdef PNG_ARM_NEON_FILE
+#  include PNG_ARM_NEON_FILE
+#endif
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
+
+#ifndef PNG_ALIGNED_MEMORY_SUPPORTED
+#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#endif
+
+void
+png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
+{
+   /* The switch statement is compiled in for ARM_NEON_API, the call to
+    * png_have_neon is compiled in for ARM_NEON_CHECK.  If both are defined
+    * the check is only performed if the API has not set the NEON option on
+    * or off explicitly.  In this case the check controls what happens.
+    *
+    * If the CHECK is not compiled in and the option is UNSET the behavior prior
+    * to 1.6.7 was to use the NEON code - this was a bug caused by having the
+    * wrong order of the 'ON' and 'default' cases.  UNSET now defaults to OFF,
+    * as documented in png.h
+    */
+   png_debug(1, "in png_init_filter_functions_neon");
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+   switch ((pp->options >> PNG_ARM_NEON) & 3)
+   {
+      case PNG_OPTION_UNSET:
+         /* Allow the run-time check to execute if it has been enabled -
+          * thus both API and CHECK can be turned on.  If it isn't supported
+          * this case will fall through to the 'default' below, which just
+          * returns.
+          */
+#endif /* PNG_ARM_NEON_API_SUPPORTED */
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
+         {
+            static volatile sig_atomic_t no_neon = -1; /* not checked */
+
+            if (no_neon < 0)
+               no_neon = !png_have_neon(pp);
+
+            if (no_neon)
+               return;
+         }
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+         break;
+#endif
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
+
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+      default: /* OFF or INVALID */
+         return;
+
+      case PNG_OPTION_ON:
+         /* Option turned on */
+         break;
+   }
+#endif
+
+   /* IMPORTANT: any new external functions used here must be declared using
+    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
+    * 'prefix' option to configure works:
+    *
+    *    ./configure --with-libpng-prefix=foobar_
+    *
+    * Verify you have got this right by running the above command, doing a build
+    * and examining pngprefix.h; it must contain a #define for every external
+    * function you add.  (Notice that this happens automatically for the
+    * initialization function.)
+    */
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
+
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth3_neon;
+   }
+
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+          png_read_filter_row_paeth4_neon;
+   }
+}
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/arm/filter_neon.S
===================================================================
--- /trunk/src/libs/libpng-1.6.45/arm/filter_neon.S	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/arm/filter_neon.S	(revision 107811)
@@ -0,0 +1,253 @@
+
+/* filter_neon.S - NEON optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2014,2017 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* This is required to get the symbol renames, which are #defines, and the
+ * definitions (or not) of PNG_ARM_NEON_OPT and PNG_ARM_NEON_IMPLEMENTATION.
+ */
+#define PNG_VERSION_INFO_ONLY
+#include "../pngpriv.h"
+
+#if (defined(__linux__) || defined(__FreeBSD__)) && defined(__ELF__)
+.section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
+#endif
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Assembler NEON support - only works for 32-bit ARM (i.e. it does not work for
+ * ARM64).  The code in arm/filter_neon_intrinsics.c supports ARM64, however it
+ * only works if -mfpu=neon is specified on the GCC command line.  See pngpriv.h
+ * for the logic which sets PNG_USE_ARM_NEON_ASM:
+ */
+#if PNG_ARM_NEON_IMPLEMENTATION == 2 /* hand-coded assembler */
+
+#if PNG_ARM_NEON_OPT > 0
+
+#ifdef __ELF__
+#   define ELF
+#else
+#   define ELF @
+#endif
+
+        .arch armv7-a
+        .fpu  neon
+
+.macro  func    name, export=0
+    .macro endfunc
+ELF     .size   \name, . - \name
+        .endfunc
+        .purgem endfunc
+    .endm
+        .text
+
+        /* Explicitly specifying alignment here because some versions of
+         * GAS don't align code correctly.  This is harmless in correctly
+         * written versions of GAS.
+         */
+        .align 2
+
+    .if \export
+        .global \name
+    .endif
+ELF     .type   \name, STT_FUNC
+        .func   \name
+\name:
+.endm
+
+func    png_read_filter_row_sub4_neon, export=1
+        ldr             r3,  [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+1:
+        vld4.32         {d4[],d5[],d6[],d7[]},    [r1,:128]
+        vadd.u8         d0,  d3,  d4
+        vadd.u8         d1,  d0,  d5
+        vadd.u8         d2,  d1,  d6
+        vadd.u8         d3,  d2,  d7
+        vst4.32         {d0[0],d1[0],d2[0],d3[0]},[r1,:128]!
+        subs            r3,  r3,  #16
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_sub3_neon, export=1
+        ldr             r3,  [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+        mov             r0,  r1
+        mov             r2,  #3
+        mov             r12, #12
+        vld1.8          {q11},    [r0], r12
+1:
+        vext.8          d5,  d22, d23, #3
+        vadd.u8         d0,  d3,  d22
+        vext.8          d6,  d22, d23, #6
+        vadd.u8         d1,  d0,  d5
+        vext.8          d7,  d23, d23, #1
+        vld1.8          {q11},    [r0], r12
+        vst1.32         {d0[0]},  [r1,:32], r2
+        vadd.u8         d2,  d1,  d6
+        vst1.32         {d1[0]},  [r1], r2
+        vadd.u8         d3,  d2,  d7
+        vst1.32         {d2[0]},  [r1], r2
+        vst1.32         {d3[0]},  [r1], r2
+        subs            r3,  r3,  #12
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_up_neon, export=1
+        ldr             r3,  [r0, #4]           @ rowbytes
+1:
+        vld1.8          {q0}, [r1,:128]
+        vld1.8          {q1}, [r2,:128]!
+        vadd.u8         q0,  q0,  q1
+        vst1.8          {q0}, [r1,:128]!
+        subs            r3,  r3,  #16
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_avg4_neon, export=1
+        ldr             r12, [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+1:
+        vld4.32         {d4[],d5[],d6[],d7[]},    [r1,:128]
+        vld4.32         {d16[],d17[],d18[],d19[]},[r2,:128]!
+        vhadd.u8        d0,  d3,  d16
+        vadd.u8         d0,  d0,  d4
+        vhadd.u8        d1,  d0,  d17
+        vadd.u8         d1,  d1,  d5
+        vhadd.u8        d2,  d1,  d18
+        vadd.u8         d2,  d2,  d6
+        vhadd.u8        d3,  d2,  d19
+        vadd.u8         d3,  d3,  d7
+        vst4.32         {d0[0],d1[0],d2[0],d3[0]},[r1,:128]!
+        subs            r12, r12, #16
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_avg3_neon, export=1
+        push            {r4,lr}
+        ldr             r12, [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+        mov             r0,  r1
+        mov             r4,  #3
+        mov             lr,  #12
+        vld1.8          {q11},    [r0], lr
+1:
+        vld1.8          {q10},    [r2], lr
+        vext.8          d5,  d22, d23, #3
+        vhadd.u8        d0,  d3,  d20
+        vext.8          d17, d20, d21, #3
+        vadd.u8         d0,  d0,  d22
+        vext.8          d6,  d22, d23, #6
+        vhadd.u8        d1,  d0,  d17
+        vext.8          d18, d20, d21, #6
+        vadd.u8         d1,  d1,  d5
+        vext.8          d7,  d23, d23, #1
+        vld1.8          {q11},    [r0], lr
+        vst1.32         {d0[0]},  [r1,:32], r4
+        vhadd.u8        d2,  d1,  d18
+        vst1.32         {d1[0]},  [r1], r4
+        vext.8          d19, d21, d21, #1
+        vadd.u8         d2,  d2,  d6
+        vhadd.u8        d3,  d2,  d19
+        vst1.32         {d2[0]},  [r1], r4
+        vadd.u8         d3,  d3,  d7
+        vst1.32         {d3[0]},  [r1], r4
+        subs            r12, r12, #12
+        bgt             1b
+
+        pop             {r4,pc}
+endfunc
+
+.macro  paeth           rx,  ra,  rb,  rc
+        vaddl.u8        q12, \ra, \rb           @ a + b
+        vaddl.u8        q15, \rc, \rc           @ 2*c
+        vabdl.u8        q13, \rb, \rc           @ pa
+        vabdl.u8        q14, \ra, \rc           @ pb
+        vabd.u16        q15, q12, q15           @ pc
+        vcle.u16        q12, q13, q14           @ pa <= pb
+        vcle.u16        q13, q13, q15           @ pa <= pc
+        vcle.u16        q14, q14, q15           @ pb <= pc
+        vand            q12, q12, q13           @ pa <= pb && pa <= pc
+        vmovn.u16       d28, q14
+        vmovn.u16       \rx, q12
+        vbsl            d28, \rb, \rc
+        vbsl            \rx, \ra, d28
+.endm
+
+func    png_read_filter_row_paeth4_neon, export=1
+        ldr             r12, [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+        vmov.i8         d20, #0
+1:
+        vld4.32         {d4[],d5[],d6[],d7[]},    [r1,:128]
+        vld4.32         {d16[],d17[],d18[],d19[]},[r2,:128]!
+        paeth           d0,  d3,  d16, d20
+        vadd.u8         d0,  d0,  d4
+        paeth           d1,  d0,  d17, d16
+        vadd.u8         d1,  d1,  d5
+        paeth           d2,  d1,  d18, d17
+        vadd.u8         d2,  d2,  d6
+        paeth           d3,  d2,  d19, d18
+        vmov            d20, d19
+        vadd.u8         d3,  d3,  d7
+        vst4.32         {d0[0],d1[0],d2[0],d3[0]},[r1,:128]!
+        subs            r12, r12, #16
+        bgt             1b
+
+        bx              lr
+endfunc
+
+func    png_read_filter_row_paeth3_neon, export=1
+        push            {r4,lr}
+        ldr             r12, [r0, #4]           @ rowbytes
+        vmov.i8         d3,  #0
+        vmov.i8         d4,  #0
+        mov             r0,  r1
+        mov             r4,  #3
+        mov             lr,  #12
+        vld1.8          {q11},    [r0], lr
+1:
+        vld1.8          {q10},    [r2], lr
+        paeth           d0,  d3,  d20, d4
+        vext.8          d5,  d22, d23, #3
+        vadd.u8         d0,  d0,  d22
+        vext.8          d17, d20, d21, #3
+        paeth           d1,  d0,  d17, d20
+        vst1.32         {d0[0]},  [r1,:32], r4
+        vext.8          d6,  d22, d23, #6
+        vadd.u8         d1,  d1,  d5
+        vext.8          d18, d20, d21, #6
+        paeth           d2,  d1,  d18, d17
+        vext.8          d7,  d23, d23, #1
+        vld1.8          {q11},    [r0], lr
+        vst1.32         {d1[0]},  [r1], r4
+        vadd.u8         d2,  d2,  d6
+        vext.8          d19, d21, d21, #1
+        paeth           d3,  d2,  d19, d18
+        vst1.32         {d2[0]},  [r1], r4
+        vmov            d4,  d19
+        vadd.u8         d3,  d3,  d7
+        vst1.32         {d3[0]},  [r1], r4
+        subs            r12, r12, #12
+        bgt             1b
+
+        pop             {r4,pc}
+endfunc
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* PNG_ARM_NEON_IMPLEMENTATION == 2 (assembler) */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/arm/filter_neon_intrinsics.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/arm/filter_neon_intrinsics.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/arm/filter_neon_intrinsics.c	(revision 107811)
@@ -0,0 +1,402 @@
+
+/* filter_neon_intrinsics.c - NEON optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2014,2016 Glenn Randers-Pehrson
+ * Written by James Yu <james.yu at linaro.org>, October 2013.
+ * Based on filter_neon.S, written by Mans Rullgard, 2011.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* This code requires -mfpu=neon on the command line: */
+#if PNG_ARM_NEON_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+#if defined(_MSC_VER) && !defined(__clang__) && defined(_M_ARM64)
+#  include <arm64_neon.h>
+#else
+#  include <arm_neon.h>
+#endif
+
+/* libpng row pointers are not necessarily aligned to any particular boundary,
+ * however this code will only work with appropriate alignment.  arm/arm_init.c
+ * checks for this (and will not compile unless it is done). This code uses
+ * variants of png_aligncast to avoid compiler warnings.
+ */
+#define png_ptr(type,pointer) png_aligncast(type *,pointer)
+#define png_ptrc(type,pointer) png_aligncastconst(const type *,pointer)
+
+/* The following relies on a variable 'temp_pointer' being declared with type
+ * 'type'.  This is written this way just to hide the GCC strict aliasing
+ * warning; note that the code is safe because there never is an alias between
+ * the input and output pointers.
+ *
+ * When compiling with MSVC ARM64, the png_ldr macro can't be passed directly
+ * to vst4_lane_u32, because of an internal compiler error inside MSVC.
+ * To avoid this compiler bug, we use a temporary variable (vdest_val) to store
+ * the result of png_ldr.
+ */
+#define png_ldr(type,pointer)\
+   (temp_pointer = png_ptr(type,pointer), *temp_pointer)
+
+#if PNG_ARM_NEON_OPT > 0
+
+void
+png_read_filter_row_up_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+   png_const_bytep pp = prev_row;
+
+   png_debug(1, "in png_read_filter_row_up_neon");
+
+   for (; rp < rp_stop; rp += 16, pp += 16)
+   {
+      uint8x16_t qrp, qpp;
+
+      qrp = vld1q_u8(rp);
+      qpp = vld1q_u8(pp);
+      qrp = vaddq_u8(qrp, qpp);
+      vst1q_u8(rp, qrp);
+   }
+}
+
+void
+png_read_filter_row_sub3_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x16_t vtmp = vld1q_u8(rp);
+   uint8x8x2_t *vrpt = png_ptr(uint8x8x2_t, &vtmp);
+   uint8x8x2_t vrp = *vrpt;
+
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   png_debug(1, "in png_read_filter_row_sub3_neon");
+
+   for (; rp < rp_stop;)
+   {
+      uint8x8_t vtmp1, vtmp2;
+      uint32x2_t *temp_pointer;
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+      vdest.val[0] = vadd_u8(vdest.val[3], vrp.val[0]);
+      vtmp2 = vext_u8(vrp.val[0], vrp.val[1], 6);
+      vdest.val[1] = vadd_u8(vdest.val[0], vtmp1);
+
+      vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+      vdest.val[2] = vadd_u8(vdest.val[1], vtmp2);
+      vdest.val[3] = vadd_u8(vdest.val[2], vtmp1);
+
+      vtmp = vld1q_u8(rp + 12);
+      vrpt = png_ptr(uint8x8x2_t, &vtmp);
+      vrp = *vrpt;
+
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+      rp += 3;
+   }
+
+   PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_sub4_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   png_debug(1, "in png_read_filter_row_sub4_neon");
+
+   for (; rp < rp_stop; rp += 16)
+   {
+      uint32x2x4_t vtmp = vld4_u32(png_ptr(uint32_t,rp));
+      uint8x8x4_t *vrpt = png_ptr(uint8x8x4_t,&vtmp);
+      uint8x8x4_t vrp = *vrpt;
+      uint32x2x4_t *temp_pointer;
+      uint32x2x4_t vdest_val;
+
+      vdest.val[0] = vadd_u8(vdest.val[3], vrp.val[0]);
+      vdest.val[1] = vadd_u8(vdest.val[0], vrp.val[1]);
+      vdest.val[2] = vadd_u8(vdest.val[1], vrp.val[2]);
+      vdest.val[3] = vadd_u8(vdest.val[2], vrp.val[3]);
+
+      vdest_val = png_ldr(uint32x2x4_t, &vdest);
+      vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
+   }
+
+   PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_avg3_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x16_t vtmp;
+   uint8x8x2_t *vrpt;
+   uint8x8x2_t vrp;
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   vtmp = vld1q_u8(rp);
+   vrpt = png_ptr(uint8x8x2_t,&vtmp);
+   vrp = *vrpt;
+
+   png_debug(1, "in png_read_filter_row_avg3_neon");
+
+   for (; rp < rp_stop; pp += 12)
+   {
+      uint8x8_t vtmp1, vtmp2, vtmp3;
+
+      uint8x8x2_t *vppt;
+      uint8x8x2_t vpp;
+
+      uint32x2_t *temp_pointer;
+
+      vtmp = vld1q_u8(pp);
+      vppt = png_ptr(uint8x8x2_t,&vtmp);
+      vpp = *vppt;
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+      vdest.val[0] = vhadd_u8(vdest.val[3], vpp.val[0]);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+
+      vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 3);
+      vtmp3 = vext_u8(vrp.val[0], vrp.val[1], 6);
+      vdest.val[1] = vhadd_u8(vdest.val[0], vtmp2);
+      vdest.val[1] = vadd_u8(vdest.val[1], vtmp1);
+
+      vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 6);
+      vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+
+      vtmp = vld1q_u8(rp + 12);
+      vrpt = png_ptr(uint8x8x2_t,&vtmp);
+      vrp = *vrpt;
+
+      vdest.val[2] = vhadd_u8(vdest.val[1], vtmp2);
+      vdest.val[2] = vadd_u8(vdest.val[2], vtmp3);
+
+      vtmp2 = vext_u8(vpp.val[1], vpp.val[1], 1);
+
+      vdest.val[3] = vhadd_u8(vdest.val[2], vtmp2);
+      vdest.val[3] = vadd_u8(vdest.val[3], vtmp1);
+
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+      rp += 3;
+   }
+}
+
+void
+png_read_filter_row_avg4_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+   png_const_bytep pp = prev_row;
+
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   png_debug(1, "in png_read_filter_row_avg4_neon");
+
+   for (; rp < rp_stop; rp += 16, pp += 16)
+   {
+      uint32x2x4_t vtmp;
+      uint8x8x4_t *vrpt, *vppt;
+      uint8x8x4_t vrp, vpp;
+      uint32x2x4_t *temp_pointer;
+      uint32x2x4_t vdest_val;
+
+      vtmp = vld4_u32(png_ptr(uint32_t,rp));
+      vrpt = png_ptr(uint8x8x4_t,&vtmp);
+      vrp = *vrpt;
+      vtmp = vld4_u32(png_ptrc(uint32_t,pp));
+      vppt = png_ptr(uint8x8x4_t,&vtmp);
+      vpp = *vppt;
+
+      vdest.val[0] = vhadd_u8(vdest.val[3], vpp.val[0]);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+      vdest.val[1] = vhadd_u8(vdest.val[0], vpp.val[1]);
+      vdest.val[1] = vadd_u8(vdest.val[1], vrp.val[1]);
+      vdest.val[2] = vhadd_u8(vdest.val[1], vpp.val[2]);
+      vdest.val[2] = vadd_u8(vdest.val[2], vrp.val[2]);
+      vdest.val[3] = vhadd_u8(vdest.val[2], vpp.val[3]);
+      vdest.val[3] = vadd_u8(vdest.val[3], vrp.val[3]);
+
+      vdest_val = png_ldr(uint32x2x4_t, &vdest);
+      vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
+   }
+}
+
+static uint8x8_t
+paeth(uint8x8_t a, uint8x8_t b, uint8x8_t c)
+{
+   uint8x8_t d, e;
+   uint16x8_t p1, pa, pb, pc;
+
+   p1 = vaddl_u8(a, b); /* a + b */
+   pc = vaddl_u8(c, c); /* c * 2 */
+   pa = vabdl_u8(b, c); /* pa */
+   pb = vabdl_u8(a, c); /* pb */
+   pc = vabdq_u16(p1, pc); /* pc */
+
+   p1 = vcleq_u16(pa, pb); /* pa <= pb */
+   pa = vcleq_u16(pa, pc); /* pa <= pc */
+   pb = vcleq_u16(pb, pc); /* pb <= pc */
+
+   p1 = vandq_u16(p1, pa); /* pa <= pb && pa <= pc */
+
+   d = vmovn_u16(pb);
+   e = vmovn_u16(p1);
+
+   d = vbsl_u8(d, b, c);
+   e = vbsl_u8(e, a, d);
+
+   return e;
+}
+
+void
+png_read_filter_row_paeth3_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+
+   uint8x16_t vtmp;
+   uint8x8x2_t *vrpt;
+   uint8x8x2_t vrp;
+   uint8x8_t vlast = vdup_n_u8(0);
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   vtmp = vld1q_u8(rp);
+   vrpt = png_ptr(uint8x8x2_t,&vtmp);
+   vrp = *vrpt;
+
+   png_debug(1, "in png_read_filter_row_paeth3_neon");
+
+   for (; rp < rp_stop; pp += 12)
+   {
+      uint8x8x2_t *vppt;
+      uint8x8x2_t vpp;
+      uint8x8_t vtmp1, vtmp2, vtmp3;
+      uint32x2_t *temp_pointer;
+
+      vtmp = vld1q_u8(pp);
+      vppt = png_ptr(uint8x8x2_t,&vtmp);
+      vpp = *vppt;
+
+      vdest.val[0] = paeth(vdest.val[3], vpp.val[0], vlast);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+      vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 3);
+      vdest.val[1] = paeth(vdest.val[0], vtmp2, vpp.val[0]);
+      vdest.val[1] = vadd_u8(vdest.val[1], vtmp1);
+
+      vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 6);
+      vtmp3 = vext_u8(vpp.val[0], vpp.val[1], 6);
+      vdest.val[2] = paeth(vdest.val[1], vtmp3, vtmp2);
+      vdest.val[2] = vadd_u8(vdest.val[2], vtmp1);
+
+      vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+      vtmp2 = vext_u8(vpp.val[1], vpp.val[1], 1);
+
+      vtmp = vld1q_u8(rp + 12);
+      vrpt = png_ptr(uint8x8x2_t,&vtmp);
+      vrp = *vrpt;
+
+      vdest.val[3] = paeth(vdest.val[2], vtmp2, vtmp3);
+      vdest.val[3] = vadd_u8(vdest.val[3], vtmp1);
+
+      vlast = vtmp2;
+
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+      rp += 3;
+      vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+      rp += 3;
+   }
+}
+
+void
+png_read_filter_row_paeth4_neon(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_bytep rp = row;
+   png_bytep rp_stop = row + row_info->rowbytes;
+   png_const_bytep pp = prev_row;
+
+   uint8x8_t vlast = vdup_n_u8(0);
+   uint8x8x4_t vdest;
+   vdest.val[3] = vdup_n_u8(0);
+
+   png_debug(1, "in png_read_filter_row_paeth4_neon");
+
+   for (; rp < rp_stop; rp += 16, pp += 16)
+   {
+      uint32x2x4_t vtmp;
+      uint8x8x4_t *vrpt, *vppt;
+      uint8x8x4_t vrp, vpp;
+      uint32x2x4_t *temp_pointer;
+      uint32x2x4_t vdest_val;
+
+      vtmp = vld4_u32(png_ptr(uint32_t,rp));
+      vrpt = png_ptr(uint8x8x4_t,&vtmp);
+      vrp = *vrpt;
+      vtmp = vld4_u32(png_ptrc(uint32_t,pp));
+      vppt = png_ptr(uint8x8x4_t,&vtmp);
+      vpp = *vppt;
+
+      vdest.val[0] = paeth(vdest.val[3], vpp.val[0], vlast);
+      vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+      vdest.val[1] = paeth(vdest.val[0], vpp.val[1], vpp.val[0]);
+      vdest.val[1] = vadd_u8(vdest.val[1], vrp.val[1]);
+      vdest.val[2] = paeth(vdest.val[1], vpp.val[2], vpp.val[1]);
+      vdest.val[2] = vadd_u8(vdest.val[2], vrp.val[2]);
+      vdest.val[3] = paeth(vdest.val[2], vpp.val[3], vpp.val[2]);
+      vdest.val[3] = vadd_u8(vdest.val[3], vrp.val[3]);
+
+      vlast = vpp.val[3];
+
+      vdest_val = png_ldr(uint32x2x4_t, &vdest);
+      vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
+   }
+}
+
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* PNG_ARM_NEON_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/arm/palette_neon_intrinsics.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/arm/palette_neon_intrinsics.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/arm/palette_neon_intrinsics.c	(revision 107811)
@@ -0,0 +1,151 @@
+
+/* palette_neon_intrinsics.c - NEON optimised palette expansion functions
+ *
+ * Copyright (c) 2018-2019 Cosmin Truta
+ * Copyright (c) 2017-2018 Arm Holdings. All rights reserved.
+ * Written by Richard Townsend <Richard.Townsend@arm.com>, February 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "../pngpriv.h"
+
+#if PNG_ARM_NEON_IMPLEMENTATION == 1
+
+#if defined(_MSC_VER) && !defined(__clang__) && defined(_M_ARM64)
+#  include <arm64_neon.h>
+#else
+#  include <arm_neon.h>
+#endif
+
+/* Build an RGBA8 palette from the separate RGB and alpha palettes. */
+void
+png_riffle_palette_neon(png_structrp png_ptr)
+{
+   png_const_colorp palette = png_ptr->palette;
+   png_bytep riffled_palette = png_ptr->riffled_palette;
+   png_const_bytep trans_alpha = png_ptr->trans_alpha;
+   int num_trans = png_ptr->num_trans;
+   int i;
+
+   /* Initially black, opaque. */
+   uint8x16x4_t w = {{
+      vdupq_n_u8(0x00),
+      vdupq_n_u8(0x00),
+      vdupq_n_u8(0x00),
+      vdupq_n_u8(0xff),
+   }};
+
+   png_debug(1, "in png_riffle_palette_neon");
+
+   /* First, riffle the RGB colours into an RGBA8 palette.
+    * The alpha component is set to opaque for now.
+    */
+   for (i = 0; i < 256; i += 16)
+   {
+      uint8x16x3_t v = vld3q_u8((png_const_bytep)(palette + i));
+      w.val[0] = v.val[0];
+      w.val[1] = v.val[1];
+      w.val[2] = v.val[2];
+      vst4q_u8(riffled_palette + (i << 2), w);
+   }
+
+   /* Fix up the missing transparency values. */
+   for (i = 0; i < num_trans; i++)
+      riffled_palette[(i << 2) + 3] = trans_alpha[i];
+}
+
+/* Expands a palettized row into RGBA8. */
+int
+png_do_expand_palette_rgba8_neon(png_structrp png_ptr, png_row_infop row_info,
+    png_const_bytep row, png_bytepp ssp, png_bytepp ddp)
+{
+   png_uint_32 row_width = row_info->width;
+   const png_uint_32 *riffled_palette =
+      (const png_uint_32 *)png_ptr->riffled_palette;
+   const png_uint_32 pixels_per_chunk = 4;
+   png_uint_32 i;
+
+   png_debug(1, "in png_do_expand_palette_rgba8_neon");
+
+   PNG_UNUSED(row)
+   if (row_width < pixels_per_chunk)
+      return 0;
+
+   /* This function originally gets the last byte of the output row.
+    * The NEON part writes forward from a given position, so we have
+    * to seek this back by 4 pixels x 4 bytes.
+    */
+   *ddp = *ddp - ((pixels_per_chunk * sizeof(png_uint_32)) - 1);
+
+   for (i = 0; i < row_width; i += pixels_per_chunk)
+   {
+      uint32x4_t cur;
+      png_bytep sp = *ssp - i, dp = *ddp - (i << 2);
+      cur = vld1q_dup_u32 (riffled_palette + *(sp - 3));
+      cur = vld1q_lane_u32(riffled_palette + *(sp - 2), cur, 1);
+      cur = vld1q_lane_u32(riffled_palette + *(sp - 1), cur, 2);
+      cur = vld1q_lane_u32(riffled_palette + *(sp - 0), cur, 3);
+      vst1q_u32((void *)dp, cur);
+   }
+   if (i != row_width)
+   {
+      /* Remove the amount that wasn't processed. */
+      i -= pixels_per_chunk;
+   }
+
+   /* Decrement output pointers. */
+   *ssp = *ssp - i;
+   *ddp = *ddp - (i << 2);
+   return i;
+}
+
+/* Expands a palettized row into RGB8. */
+int
+png_do_expand_palette_rgb8_neon(png_structrp png_ptr, png_row_infop row_info,
+    png_const_bytep row, png_bytepp ssp, png_bytepp ddp)
+{
+   png_uint_32 row_width = row_info->width;
+   png_const_bytep palette = (png_const_bytep)png_ptr->palette;
+   const png_uint_32 pixels_per_chunk = 8;
+   png_uint_32 i;
+
+   png_debug(1, "in png_do_expand_palette_rgb8_neon");
+
+   PNG_UNUSED(row)
+   if (row_width <= pixels_per_chunk)
+      return 0;
+
+   /* Seeking this back by 8 pixels x 3 bytes. */
+   *ddp = *ddp - ((pixels_per_chunk * sizeof(png_color)) - 1);
+
+   for (i = 0; i < row_width; i += pixels_per_chunk)
+   {
+      uint8x8x3_t cur;
+      png_bytep sp = *ssp - i, dp = *ddp - ((i << 1) + i);
+      cur = vld3_dup_u8(palette + sizeof(png_color) * (*(sp - 7)));
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 6)), cur, 1);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 5)), cur, 2);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 4)), cur, 3);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 3)), cur, 4);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 2)), cur, 5);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 1)), cur, 6);
+      cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 0)), cur, 7);
+      vst3_u8((void *)dp, cur);
+   }
+
+   if (i != row_width)
+   {
+      /* Remove the amount that wasn't processed. */
+      i -= pixels_per_chunk;
+   }
+
+   /* Decrement output pointers. */
+   *ssp = *ssp - i;
+   *ddp = *ddp - ((i << 1) + i);
+   return i;
+}
+
+#endif /* PNG_ARM_NEON_IMPLEMENTATION */
Index: /trunk/src/libs/libpng-1.6.45/autogen.sh
===================================================================
--- /trunk/src/libs/libpng-1.6.45/autogen.sh	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/autogen.sh	(revision 107811)
@@ -0,0 +1,226 @@
+#! /bin/sh
+#
+# Run 'autoreconf' to build 'configure', 'Makefile.in' and other configure
+# control files.
+#
+# The first time this is run on a GIT checkout the only files that exist are
+# configure.ac and Makefile.am; all of the autotools support scripts are
+# missing.  They are instantiated with autoreconf --force --install.
+#
+# For regular ("tarball") distributions all the files should exist.  We do not
+# want them to be updated *under any circumstances*.  It should never be
+# necessary to run autogen.sh because ./configure --enable-maintainer-mode says
+# what to do if Makefile.am or configure.ac are changed.
+#
+# It is *probably* OK to update the files on a GIT checkout, because they have
+# come from the local tools, but leave that to the user who is assumed to know
+# whether it is ok or required.
+#
+# This script is intended to work without arguments, there are, however, hidden
+# arguments (a) for use while testing the script and (b) to fix up systems that
+# have been broken.  If (b) is required the script prompts for the correct
+# options.  For this reason the options are *NOT* documented in the help; this
+# is deliberate; UTSL.
+#
+clean=
+maintainer=
+while test $# -gt 0
+do
+   case "$1" in
+      --maintainer)
+         maintainer=1;;
+
+      --clean)
+         clean=1;;
+
+      *)
+         exec >&2
+         echo "$0: usage: ./autogen.sh"
+         if test -d .git
+         then
+            echo "  ./autogen.sh generates the configure script and"
+            echo "  Makefile.in, or refreshes them after changes to Makefile.am"
+            echo "  or configure.ac.  You may prefer to just run autoreconf."
+         elif test -z "$maintainer"
+         then
+            echo "  DO NOT RUN THIS SCRIPT."
+            echo "  If you need to change Makefile.am or configure.ac then you"
+            echo "  also need to run ./configure --enable-maintainer-mode and"
+            echo "  use the appropriate autotools, *NOT* this script, to update"
+            echo "  everything, please check the documentation of autoreconf."
+            echo "  WARNING: libpng is intentionally generated with a known,"
+            echo "  fixed, set of autotools.  It is known *NOT* to work with"
+            echo "  the collection of autotools distributed on highly reputable"
+            echo "  operating systems."
+            echo "  Remember: autotools is GNU software, you are expected to"
+            echo "  pay for support."
+         else
+            echo "  You have run autogen.sh with --maintainer enabled and you"
+            echo "  are not using a GIT distribution, then you have given an"
+            echo "  unrecognized argument.  This is not good. --maintainer"
+            echo "  switches off any assumptions that you might not know what"
+            echo "  you are doing."
+         fi
+         exit 1;;
+   esac
+
+   shift
+done
+#
+# First check for a set of the autotools files; if absent then this is assumed
+# to be a GIT version and the local autotools must be used.  If present this
+# is a tarball distribution and the script should not be used.  If partially
+# present bad things are happening.
+#
+# The autotools generated files:
+libpng_autotools_files="Makefile.in aclocal.m4 config.guess config.h.in
+   config.sub configure depcomp install-sh ltmain.sh missing\
+   test-driver"
+#
+# Files generated by versions of autoconf >2.68 or automake >1.13 (i.e. later
+# versions than those required by configure.ac):
+libpng_autotools_extra="compile config.h.in~"
+#
+# These are separate because 'maintainer-clean' does not remove them.
+libpng_libtool_files="scripts/autoconf/libtool.m4 scripts/autoconf/ltoptions.m4\
+   scripts/autoconf/ltsugar.m4 scripts/autoconf/ltversion.m4\
+   scripts/autoconf/lt~obsolete.m4"
+
+libpng_autotools_dirs="autom4te.cache" # not required
+#
+# The configure generated files:
+libpng_configure_files="Makefile config.h config.log config.status\
+   libpng-config libpng.pc libtool stamp-h1"
+
+libpng_configure_dirs=".deps"
+#
+# We must remove the configure generated files as well as the autotools
+# generated files if autotools are regenerated because otherwise if configure
+# has been run without "--enable-maintainer-mode" make can do a partial update
+# of Makefile.  These functions do the two bits of cleaning.
+clean_autotools(){
+   rm -rf $libpng_autotools_files $libpng_libtool_files $libpng_autotools_dirs
+   rm -rf $libpng_autotools_extra
+}
+
+clean_configure(){
+   rm -rf $libpng_configure_files $libpng_configure_dirs
+}
+#
+# Clean: remove everything (this is to help with testing)
+if test -n "$clean"
+then
+   clean_configure
+   if test -n "$maintainer"
+   then
+      clean_autotools
+   fi
+
+   exit 0
+fi
+#
+# Validate the distribution.
+libpng_autotools_file_found=
+libpng_autotools_file_missing=
+for file in $libpng_autotools_files
+do
+   if test -f  "$file"
+   then
+      libpng_autotools_file_found=1
+   else
+      libpng_autotools_file_missing=1
+   fi
+done
+#
+# Presence of one of these does not *invalidate* missing, but absence
+# invalidates found.
+for file in $libpng_libtool_files
+do
+   if test ! -f "$file"
+   then
+      libpng_autotools_file_missing=1
+   fi
+done
+#
+# The cache directory doesn't matter - it will be regenerated and does not exist
+# anyway in a tarball.
+#
+# Either everything is missing or everything is there, the --maintainer option
+# just changes this so that the mode is set to generate all the files.
+mode=
+if test -z "$libpng_autotools_file_found" -o -n "$maintainer"
+then
+   mode="autoreconf"
+else
+   if test -n "$libpng_autotools_file_missing"
+   then
+      mode="broken"
+   else
+      mode="configure"
+   fi
+fi
+#
+# So:
+case "$mode" in
+   autoreconf)
+      # Clean in case configure files exist
+      clean_configure
+      clean_autotools
+      # Everything must be initialized, so use --force
+      if autoreconf --warnings=all --force --install
+      then
+         missing=
+         for file in $libpng_autotools_files
+         do
+            test -f "$file" || missing=1
+         done
+         # ignore the cache directory
+         test -z "$missing" || {
+            exec >&2
+            echo "autoreconf was run, but did not produce all the expected"
+            echo "files.  It is likely that your autotools installation is"
+            echo "not compatible with that expected by libpng."
+            exit 1
+         }
+      else
+         exec >&2
+         echo "autoreconf failed: your version of autotools is incompatible"
+         echo "with this libpng version.  Please use a distributed archive"
+         echo "(which includes the autotools generated files) and run configure"
+         echo "instead."
+         exit 1
+      fi;;
+
+   configure)
+      if test -d .git
+      then
+         exec >&2
+         echo "ERROR: running autoreconf on an initialized system"
+         echo "  This is not necessary; it is only necessary to remake the"
+         echo "  autotools generated files if Makefile.am or configure.ac"
+         echo "  change and make does the right thing with:"
+         echo
+         echo "     ./configure --enable-maintainer-mode."
+         echo
+         echo "  You can run autoreconf yourself if you don't like maintainer"
+         echo "  mode and you can also just run autoreconf -f -i to initialize"
+         echo "  everything in the first place; this script is only for"
+         echo "  compatibility with prior releases."
+         exit 1
+      else
+         exec >&2
+         echo "autogen.sh is intended only to generate 'configure' on systems"
+         echo "that do not have it.  You have a complete 'configure', if you"
+         echo "need to change Makefile.am or configure.ac you also need to"
+         echo "run configure with the --enable-maintainer-mode option."
+         exit 1
+      fi;;
+
+   broken)
+      exec >&2
+      echo "Your system has a partial set of autotools generated files."
+      echo "autogen.sh is unable to proceed.  The full set of files is"
+      echo "contained in the libpng 'tar' distribution archive and you do"
+      echo "not need to run autogen.sh if you use it."
+      exit 1;;
+esac
Index: /trunk/src/libs/libpng-1.6.45/compile
===================================================================
--- /trunk/src/libs/libpng-1.6.45/compile	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/compile	(revision 107811)
@@ -0,0 +1,348 @@
+#! /bin/sh
+# Wrapper for compilers which do not understand '-c -o'.
+
+scriptversion=2018-03-07.03; # UTC
+
+# Copyright (C) 1999-2021 Free Software Foundation, Inc.
+# Written by Tom Tromey <tromey@cygnus.com>.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# This file is maintained in Automake, please report
+# bugs to <bug-automake@gnu.org> or send patches to
+# <automake-patches@gnu.org>.
+
+nl='
+'
+
+# We need space, tab and new line, in precisely that order.  Quoting is
+# there to prevent tools from complaining about whitespace usage.
+IFS=" ""	$nl"
+
+file_conv=
+
+# func_file_conv build_file lazy
+# Convert a $build file to $host form and store it in $file
+# Currently only supports Windows hosts. If the determined conversion
+# type is listed in (the comma separated) LAZY, no conversion will
+# take place.
+func_file_conv ()
+{
+  file=$1
+  case $file in
+    / | /[!/]*) # absolute file, and not a UNC file
+      if test -z "$file_conv"; then
+	# lazily determine how to convert abs files
+	case `uname -s` in
+	  MINGW*)
+	    file_conv=mingw
+	    ;;
+	  CYGWIN* | MSYS*)
+	    file_conv=cygwin
+	    ;;
+	  *)
+	    file_conv=wine
+	    ;;
+	esac
+      fi
+      case $file_conv/,$2, in
+	*,$file_conv,*)
+	  ;;
+	mingw/*)
+	  file=`cmd //C echo "$file " | sed -e 's/"\(.*\) " *$/\1/'`
+	  ;;
+	cygwin/* | msys/*)
+	  file=`cygpath -m "$file" || echo "$file"`
+	  ;;
+	wine/*)
+	  file=`winepath -w "$file" || echo "$file"`
+	  ;;
+      esac
+      ;;
+  esac
+}
+
+# func_cl_dashL linkdir
+# Make cl look for libraries in LINKDIR
+func_cl_dashL ()
+{
+  func_file_conv "$1"
+  if test -z "$lib_path"; then
+    lib_path=$file
+  else
+    lib_path="$lib_path;$file"
+  fi
+  linker_opts="$linker_opts -LIBPATH:$file"
+}
+
+# func_cl_dashl library
+# Do a library search-path lookup for cl
+func_cl_dashl ()
+{
+  lib=$1
+  found=no
+  save_IFS=$IFS
+  IFS=';'
+  for dir in $lib_path $LIB
+  do
+    IFS=$save_IFS
+    if $shared && test -f "$dir/$lib.dll.lib"; then
+      found=yes
+      lib=$dir/$lib.dll.lib
+      break
+    fi
+    if test -f "$dir/$lib.lib"; then
+      found=yes
+      lib=$dir/$lib.lib
+      break
+    fi
+    if test -f "$dir/lib$lib.a"; then
+      found=yes
+      lib=$dir/lib$lib.a
+      break
+    fi
+  done
+  IFS=$save_IFS
+
+  if test "$found" != yes; then
+    lib=$lib.lib
+  fi
+}
+
+# func_cl_wrapper cl arg...
+# Adjust compile command to suit cl
+func_cl_wrapper ()
+{
+  # Assume a capable shell
+  lib_path=
+  shared=:
+  linker_opts=
+  for arg
+  do
+    if test -n "$eat"; then
+      eat=
+    else
+      case $1 in
+	-o)
+	  # configure might choose to run compile as 'compile cc -o foo foo.c'.
+	  eat=1
+	  case $2 in
+	    *.o | *.[oO][bB][jJ])
+	      func_file_conv "$2"
+	      set x "$@" -Fo"$file"
+	      shift
+	      ;;
+	    *)
+	      func_file_conv "$2"
+	      set x "$@" -Fe"$file"
+	      shift
+	      ;;
+	  esac
+	  ;;
+	-I)
+	  eat=1
+	  func_file_conv "$2" mingw
+	  set x "$@" -I"$file"
+	  shift
+	  ;;
+	-I*)
+	  func_file_conv "${1#-I}" mingw
+	  set x "$@" -I"$file"
+	  shift
+	  ;;
+	-l)
+	  eat=1
+	  func_cl_dashl "$2"
+	  set x "$@" "$lib"
+	  shift
+	  ;;
+	-l*)
+	  func_cl_dashl "${1#-l}"
+	  set x "$@" "$lib"
+	  shift
+	  ;;
+	-L)
+	  eat=1
+	  func_cl_dashL "$2"
+	  ;;
+	-L*)
+	  func_cl_dashL "${1#-L}"
+	  ;;
+	-static)
+	  shared=false
+	  ;;
+	-Wl,*)
+	  arg=${1#-Wl,}
+	  save_ifs="$IFS"; IFS=','
+	  for flag in $arg; do
+	    IFS="$save_ifs"
+	    linker_opts="$linker_opts $flag"
+	  done
+	  IFS="$save_ifs"
+	  ;;
+	-Xlinker)
+	  eat=1
+	  linker_opts="$linker_opts $2"
+	  ;;
+	-*)
+	  set x "$@" "$1"
+	  shift
+	  ;;
+	*.cc | *.CC | *.cxx | *.CXX | *.[cC]++)
+	  func_file_conv "$1"
+	  set x "$@" -Tp"$file"
+	  shift
+	  ;;
+	*.c | *.cpp | *.CPP | *.lib | *.LIB | *.Lib | *.OBJ | *.obj | *.[oO])
+	  func_file_conv "$1" mingw
+	  set x "$@" "$file"
+	  shift
+	  ;;
+	*)
+	  set x "$@" "$1"
+	  shift
+	  ;;
+      esac
+    fi
+    shift
+  done
+  if test -n "$linker_opts"; then
+    linker_opts="-link$linker_opts"
+  fi
+  exec "$@" $linker_opts
+  exit 1
+}
+
+eat=
+
+case $1 in
+  '')
+     echo "$0: No command.  Try '$0 --help' for more information." 1>&2
+     exit 1;
+     ;;
+  -h | --h*)
+    cat <<\EOF
+Usage: compile [--help] [--version] PROGRAM [ARGS]
+
+Wrapper for compilers which do not understand '-c -o'.
+Remove '-o dest.o' from ARGS, run PROGRAM with the remaining
+arguments, and rename the output as expected.
+
+If you are trying to build a whole package this is not the
+right script to run: please start by reading the file 'INSTALL'.
+
+Report bugs to <bug-automake@gnu.org>.
+EOF
+    exit $?
+    ;;
+  -v | --v*)
+    echo "compile $scriptversion"
+    exit $?
+    ;;
+  cl | *[/\\]cl | cl.exe | *[/\\]cl.exe | \
+  icl | *[/\\]icl | icl.exe | *[/\\]icl.exe )
+    func_cl_wrapper "$@"      # Doesn't return...
+    ;;
+esac
+
+ofile=
+cfile=
+
+for arg
+do
+  if test -n "$eat"; then
+    eat=
+  else
+    case $1 in
+      -o)
+	# configure might choose to run compile as 'compile cc -o foo foo.c'.
+	# So we strip '-o arg' only if arg is an object.
+	eat=1
+	case $2 in
+	  *.o | *.obj)
+	    ofile=$2
+	    ;;
+	  *)
+	    set x "$@" -o "$2"
+	    shift
+	    ;;
+	esac
+	;;
+      *.c)
+	cfile=$1
+	set x "$@" "$1"
+	shift
+	;;
+      *)
+	set x "$@" "$1"
+	shift
+	;;
+    esac
+  fi
+  shift
+done
+
+if test -z "$ofile" || test -z "$cfile"; then
+  # If no '-o' option was seen then we might have been invoked from a
+  # pattern rule where we don't need one.  That is ok -- this is a
+  # normal compilation that the losing compiler can handle.  If no
+  # '.c' file was seen then we are probably linking.  That is also
+  # ok.
+  exec "$@"
+fi
+
+# Name of file we expect compiler to create.
+cofile=`echo "$cfile" | sed 's|^.*[\\/]||; s|^[a-zA-Z]:||; s/\.c$/.o/'`
+
+# Create the lock directory.
+# Note: use '[/\\:.-]' here to ensure that we don't use the same name
+# that we are using for the .o file.  Also, base the name on the expected
+# object file name, since that is what matters with a parallel build.
+lockdir=`echo "$cofile" | sed -e 's|[/\\:.-]|_|g'`.d
+while true; do
+  if mkdir "$lockdir" >/dev/null 2>&1; then
+    break
+  fi
+  sleep 1
+done
+# FIXME: race condition here if user kills between mkdir and trap.
+trap "rmdir '$lockdir'; exit 1" 1 2 15
+
+# Run the compile.
+"$@"
+ret=$?
+
+if test -f "$cofile"; then
+  test "$cofile" = "$ofile" || mv "$cofile" "$ofile"
+elif test -f "${cofile}bj"; then
+  test "${cofile}bj" = "$ofile" || mv "${cofile}bj" "$ofile"
+fi
+
+rmdir "$lockdir"
+exit $ret
+
+# Local Variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
Index: /trunk/src/libs/libpng-1.6.45/config.guess
===================================================================
--- /trunk/src/libs/libpng-1.6.45/config.guess	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/config.guess	(revision 107811)
@@ -0,0 +1,1807 @@
+#! /bin/sh
+# Attempt to guess a canonical system name.
+#   Copyright 1992-2023 Free Software Foundation, Inc.
+
+# shellcheck disable=SC2006,SC2268 # see below for rationale
+
+timestamp='2023-08-22'
+
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, see <https://www.gnu.org/licenses/>.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that
+# program.  This Exception is an additional permission under section 7
+# of the GNU General Public License, version 3 ("GPLv3").
+#
+# Originally written by Per Bothner; maintained since 2000 by Ben Elliston.
+#
+# You can get the latest version of this script from:
+# https://git.savannah.gnu.org/cgit/config.git/plain/config.guess
+#
+# Please send patches to <config-patches@gnu.org>.
+
+
+# The "shellcheck disable" line above the timestamp inhibits complaints
+# about features and limitations of the classic Bourne shell that were
+# superseded or lifted in POSIX.  However, this script identifies a wide
+# variety of pre-POSIX systems that do not have POSIX shells at all, and
+# even some reasonably current systems (Solaris 10 as case-in-point) still
+# have a pre-POSIX /bin/sh.
+
+
+me=`echo "$0" | sed -e 's,.*/,,'`
+
+usage="\
+Usage: $0 [OPTION]
+
+Output the configuration name of the system '$me' is run on.
+
+Options:
+  -h, --help         print this help, then exit
+  -t, --time-stamp   print date of last modification, then exit
+  -v, --version      print version number, then exit
+
+Report bugs and patches to <config-patches@gnu.org>."
+
+version="\
+GNU config.guess ($timestamp)
+
+Originally written by Per Bothner.
+Copyright 1992-2023 Free Software Foundation, Inc.
+
+This is free software; see the source for copying conditions.  There is NO
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
+
+help="
+Try '$me --help' for more information."
+
+# Parse command line
+while test $# -gt 0 ; do
+  case $1 in
+    --time-stamp | --time* | -t )
+       echo "$timestamp" ; exit ;;
+    --version | -v )
+       echo "$version" ; exit ;;
+    --help | --h* | -h )
+       echo "$usage"; exit ;;
+    -- )     # Stop option processing
+       shift; break ;;
+    - )	# Use stdin as input.
+       break ;;
+    -* )
+       echo "$me: invalid option $1$help" >&2
+       exit 1 ;;
+    * )
+       break ;;
+  esac
+done
+
+if test $# != 0; then
+  echo "$me: too many arguments$help" >&2
+  exit 1
+fi
+
+# Just in case it came from the environment.
+GUESS=
+
+# CC_FOR_BUILD -- compiler used by this script. Note that the use of a
+# compiler to aid in system detection is discouraged as it requires
+# temporary files to be created and, as you can see below, it is a
+# headache to deal with in a portable fashion.
+
+# Historically, 'CC_FOR_BUILD' used to be named 'HOST_CC'. We still
+# use 'HOST_CC' if defined, but it is deprecated.
+
+# Portable tmp directory creation inspired by the Autoconf team.
+
+tmp=
+# shellcheck disable=SC2172
+trap 'test -z "$tmp" || rm -fr "$tmp"' 0 1 2 13 15
+
+set_cc_for_build() {
+    # prevent multiple calls if $tmp is already set
+    test "$tmp" && return 0
+    : "${TMPDIR=/tmp}"
+    # shellcheck disable=SC2039,SC3028
+    { tmp=`(umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null` && test -n "$tmp" && test -d "$tmp" ; } ||
+	{ test -n "$RANDOM" && tmp=$TMPDIR/cg$$-$RANDOM && (umask 077 && mkdir "$tmp" 2>/dev/null) ; } ||
+	{ tmp=$TMPDIR/cg-$$ && (umask 077 && mkdir "$tmp" 2>/dev/null) && echo "Warning: creating insecure temp directory" >&2 ; } ||
+	{ echo "$me: cannot create a temporary directory in $TMPDIR" >&2 ; exit 1 ; }
+    dummy=$tmp/dummy
+    case ${CC_FOR_BUILD-},${HOST_CC-},${CC-} in
+	,,)    echo "int x;" > "$dummy.c"
+	       for driver in cc gcc c89 c99 ; do
+		   if ($driver -c -o "$dummy.o" "$dummy.c") >/dev/null 2>&1 ; then
+		       CC_FOR_BUILD=$driver
+		       break
+		   fi
+	       done
+	       if test x"$CC_FOR_BUILD" = x ; then
+		   CC_FOR_BUILD=no_compiler_found
+	       fi
+	       ;;
+	,,*)   CC_FOR_BUILD=$CC ;;
+	,*,*)  CC_FOR_BUILD=$HOST_CC ;;
+    esac
+}
+
+# This is needed to find uname on a Pyramid OSx when run in the BSD universe.
+# (ghazi@noc.rutgers.edu 1994-08-24)
+if test -f /.attbin/uname ; then
+	PATH=$PATH:/.attbin ; export PATH
+fi
+
+UNAME_MACHINE=`(uname -m) 2>/dev/null` || UNAME_MACHINE=unknown
+UNAME_RELEASE=`(uname -r) 2>/dev/null` || UNAME_RELEASE=unknown
+UNAME_SYSTEM=`(uname -s) 2>/dev/null` || UNAME_SYSTEM=unknown
+UNAME_VERSION=`(uname -v) 2>/dev/null` || UNAME_VERSION=unknown
+
+case $UNAME_SYSTEM in
+Linux|GNU|GNU/*)
+	LIBC=unknown
+
+	set_cc_for_build
+	cat <<-EOF > "$dummy.c"
+	#if defined(__ANDROID__)
+	LIBC=android
+	#else
+	#include <features.h>
+	#if defined(__UCLIBC__)
+	LIBC=uclibc
+	#elif defined(__dietlibc__)
+	LIBC=dietlibc
+	#elif defined(__GLIBC__)
+	LIBC=gnu
+	#else
+	#include <stdarg.h>
+	/* First heuristic to detect musl libc.  */
+	#ifdef __DEFINED_va_list
+	LIBC=musl
+	#endif
+	#endif
+	#endif
+	EOF
+	cc_set_libc=`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^LIBC' | sed 's, ,,g'`
+	eval "$cc_set_libc"
+
+	# Second heuristic to detect musl libc.
+	if [ "$LIBC" = unknown ] &&
+	   command -v ldd >/dev/null &&
+	   ldd --version 2>&1 | grep -q ^musl; then
+		LIBC=musl
+	fi
+
+	# If the system lacks a compiler, then just pick glibc.
+	# We could probably try harder.
+	if [ "$LIBC" = unknown ]; then
+		LIBC=gnu
+	fi
+	;;
+esac
+
+# Note: order is significant - the case branches are not exclusive.
+
+case $UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION in
+    *:NetBSD:*:*)
+	# NetBSD (nbsd) targets should (where applicable) match one or
+	# more of the tuples: *-*-netbsdelf*, *-*-netbsdaout*,
+	# *-*-netbsdecoff* and *-*-netbsd*.  For targets that recently
+	# switched to ELF, *-*-netbsd* would select the old
+	# object file format.  This provides both forward
+	# compatibility and a consistent mechanism for selecting the
+	# object file format.
+	#
+	# Note: NetBSD doesn't particularly care about the vendor
+	# portion of the name.  We always set it to "unknown".
+	UNAME_MACHINE_ARCH=`(uname -p 2>/dev/null || \
+	    /sbin/sysctl -n hw.machine_arch 2>/dev/null || \
+	    /usr/sbin/sysctl -n hw.machine_arch 2>/dev/null || \
+	    echo unknown)`
+	case $UNAME_MACHINE_ARCH in
+	    aarch64eb) machine=aarch64_be-unknown ;;
+	    armeb) machine=armeb-unknown ;;
+	    arm*) machine=arm-unknown ;;
+	    sh3el) machine=shl-unknown ;;
+	    sh3eb) machine=sh-unknown ;;
+	    sh5el) machine=sh5le-unknown ;;
+	    earmv*)
+		arch=`echo "$UNAME_MACHINE_ARCH" | sed -e 's,^e\(armv[0-9]\).*$,\1,'`
+		endian=`echo "$UNAME_MACHINE_ARCH" | sed -ne 's,^.*\(eb\)$,\1,p'`
+		machine=${arch}${endian}-unknown
+		;;
+	    *) machine=$UNAME_MACHINE_ARCH-unknown ;;
+	esac
+	# The Operating System including object format, if it has switched
+	# to ELF recently (or will in the future) and ABI.
+	case $UNAME_MACHINE_ARCH in
+	    earm*)
+		os=netbsdelf
+		;;
+	    arm*|i386|m68k|ns32k|sh3*|sparc|vax)
+		set_cc_for_build
+		if echo __ELF__ | $CC_FOR_BUILD -E - 2>/dev/null \
+			| grep -q __ELF__
+		then
+		    # Once all utilities can be ECOFF (netbsdecoff) or a.out (netbsdaout).
+		    # Return netbsd for either.  FIX?
+		    os=netbsd
+		else
+		    os=netbsdelf
+		fi
+		;;
+	    *)
+		os=netbsd
+		;;
+	esac
+	# Determine ABI tags.
+	case $UNAME_MACHINE_ARCH in
+	    earm*)
+		expr='s/^earmv[0-9]/-eabi/;s/eb$//'
+		abi=`echo "$UNAME_MACHINE_ARCH" | sed -e "$expr"`
+		;;
+	esac
+	# The OS release
+	# Debian GNU/NetBSD machines have a different userland, and
+	# thus, need a distinct triplet. However, they do not need
+	# kernel version information, so it can be replaced with a
+	# suitable tag, in the style of linux-gnu.
+	case $UNAME_VERSION in
+	    Debian*)
+		release='-gnu'
+		;;
+	    *)
+		release=`echo "$UNAME_RELEASE" | sed -e 's/[-_].*//' | cut -d. -f1,2`
+		;;
+	esac
+	# Since CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM:
+	# contains redundant information, the shorter form:
+	# CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM is used.
+	GUESS=$machine-${os}${release}${abi-}
+	;;
+    *:Bitrig:*:*)
+	UNAME_MACHINE_ARCH=`arch | sed 's/Bitrig.//'`
+	GUESS=$UNAME_MACHINE_ARCH-unknown-bitrig$UNAME_RELEASE
+	;;
+    *:OpenBSD:*:*)
+	UNAME_MACHINE_ARCH=`arch | sed 's/OpenBSD.//'`
+	GUESS=$UNAME_MACHINE_ARCH-unknown-openbsd$UNAME_RELEASE
+	;;
+    *:SecBSD:*:*)
+	UNAME_MACHINE_ARCH=`arch | sed 's/SecBSD.//'`
+	GUESS=$UNAME_MACHINE_ARCH-unknown-secbsd$UNAME_RELEASE
+	;;
+    *:LibertyBSD:*:*)
+	UNAME_MACHINE_ARCH=`arch | sed 's/^.*BSD\.//'`
+	GUESS=$UNAME_MACHINE_ARCH-unknown-libertybsd$UNAME_RELEASE
+	;;
+    *:MidnightBSD:*:*)
+	GUESS=$UNAME_MACHINE-unknown-midnightbsd$UNAME_RELEASE
+	;;
+    *:ekkoBSD:*:*)
+	GUESS=$UNAME_MACHINE-unknown-ekkobsd$UNAME_RELEASE
+	;;
+    *:SolidBSD:*:*)
+	GUESS=$UNAME_MACHINE-unknown-solidbsd$UNAME_RELEASE
+	;;
+    *:OS108:*:*)
+	GUESS=$UNAME_MACHINE-unknown-os108_$UNAME_RELEASE
+	;;
+    macppc:MirBSD:*:*)
+	GUESS=powerpc-unknown-mirbsd$UNAME_RELEASE
+	;;
+    *:MirBSD:*:*)
+	GUESS=$UNAME_MACHINE-unknown-mirbsd$UNAME_RELEASE
+	;;
+    *:Sortix:*:*)
+	GUESS=$UNAME_MACHINE-unknown-sortix
+	;;
+    *:Twizzler:*:*)
+	GUESS=$UNAME_MACHINE-unknown-twizzler
+	;;
+    *:Redox:*:*)
+	GUESS=$UNAME_MACHINE-unknown-redox
+	;;
+    mips:OSF1:*.*)
+	GUESS=mips-dec-osf1
+	;;
+    alpha:OSF1:*:*)
+	# Reset EXIT trap before exiting to avoid spurious non-zero exit code.
+	trap '' 0
+	case $UNAME_RELEASE in
+	*4.0)
+		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $3}'`
+		;;
+	*5.*)
+		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $4}'`
+		;;
+	esac
+	# According to Compaq, /usr/sbin/psrinfo has been available on
+	# OSF/1 and Tru64 systems produced since 1995.  I hope that
+	# covers most systems running today.  This code pipes the CPU
+	# types through head -n 1, so we only detect the type of CPU 0.
+	ALPHA_CPU_TYPE=`/usr/sbin/psrinfo -v | sed -n -e 's/^  The alpha \(.*\) processor.*$/\1/p' | head -n 1`
+	case $ALPHA_CPU_TYPE in
+	    "EV4 (21064)")
+		UNAME_MACHINE=alpha ;;
+	    "EV4.5 (21064)")
+		UNAME_MACHINE=alpha ;;
+	    "LCA4 (21066/21068)")
+		UNAME_MACHINE=alpha ;;
+	    "EV5 (21164)")
+		UNAME_MACHINE=alphaev5 ;;
+	    "EV5.6 (21164A)")
+		UNAME_MACHINE=alphaev56 ;;
+	    "EV5.6 (21164PC)")
+		UNAME_MACHINE=alphapca56 ;;
+	    "EV5.7 (21164PC)")
+		UNAME_MACHINE=alphapca57 ;;
+	    "EV6 (21264)")
+		UNAME_MACHINE=alphaev6 ;;
+	    "EV6.7 (21264A)")
+		UNAME_MACHINE=alphaev67 ;;
+	    "EV6.8CB (21264C)")
+		UNAME_MACHINE=alphaev68 ;;
+	    "EV6.8AL (21264B)")
+		UNAME_MACHINE=alphaev68 ;;
+	    "EV6.8CX (21264D)")
+		UNAME_MACHINE=alphaev68 ;;
+	    "EV6.9A (21264/EV69A)")
+		UNAME_MACHINE=alphaev69 ;;
+	    "EV7 (21364)")
+		UNAME_MACHINE=alphaev7 ;;
+	    "EV7.9 (21364A)")
+		UNAME_MACHINE=alphaev79 ;;
+	esac
+	# A Pn.n version is a patched version.
+	# A Vn.n version is a released version.
+	# A Tn.n version is a released field test version.
+	# A Xn.n version is an unreleased experimental baselevel.
+	# 1.2 uses "1.2" for uname -r.
+	OSF_REL=`echo "$UNAME_RELEASE" | sed -e 's/^[PVTX]//' | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz`
+	GUESS=$UNAME_MACHINE-dec-osf$OSF_REL
+	;;
+    Amiga*:UNIX_System_V:4.0:*)
+	GUESS=m68k-unknown-sysv4
+	;;
+    *:[Aa]miga[Oo][Ss]:*:*)
+	GUESS=$UNAME_MACHINE-unknown-amigaos
+	;;
+    *:[Mm]orph[Oo][Ss]:*:*)
+	GUESS=$UNAME_MACHINE-unknown-morphos
+	;;
+    *:OS/390:*:*)
+	GUESS=i370-ibm-openedition
+	;;
+    *:z/VM:*:*)
+	GUESS=s390-ibm-zvmoe
+	;;
+    *:OS400:*:*)
+	GUESS=powerpc-ibm-os400
+	;;
+    arm:RISC*:1.[012]*:*|arm:riscix:1.[012]*:*)
+	GUESS=arm-acorn-riscix$UNAME_RELEASE
+	;;
+    arm*:riscos:*:*|arm*:RISCOS:*:*)
+	GUESS=arm-unknown-riscos
+	;;
+    SR2?01:HI-UX/MPP:*:* | SR8000:HI-UX/MPP:*:*)
+	GUESS=hppa1.1-hitachi-hiuxmpp
+	;;
+    Pyramid*:OSx*:*:* | MIS*:OSx*:*:* | MIS*:SMP_DC-OSx*:*:*)
+	# akee@wpdis03.wpafb.af.mil (Earle F. Ake) contributed MIS and NILE.
+	case `(/bin/universe) 2>/dev/null` in
+	    att) GUESS=pyramid-pyramid-sysv3 ;;
+	    *)   GUESS=pyramid-pyramid-bsd   ;;
+	esac
+	;;
+    NILE*:*:*:dcosx)
+	GUESS=pyramid-pyramid-svr4
+	;;
+    DRS?6000:unix:4.0:6*)
+	GUESS=sparc-icl-nx6
+	;;
+    DRS?6000:UNIX_SV:4.2*:7* | DRS?6000:isis:4.2*:7*)
+	case `/usr/bin/uname -p` in
+	    sparc) GUESS=sparc-icl-nx7 ;;
+	esac
+	;;
+    s390x:SunOS:*:*)
+	SUN_REL=`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`
+	GUESS=$UNAME_MACHINE-ibm-solaris2$SUN_REL
+	;;
+    sun4H:SunOS:5.*:*)
+	SUN_REL=`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`
+	GUESS=sparc-hal-solaris2$SUN_REL
+	;;
+    sun4*:SunOS:5.*:* | tadpole*:SunOS:5.*:*)
+	SUN_REL=`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`
+	GUESS=sparc-sun-solaris2$SUN_REL
+	;;
+    i86pc:AuroraUX:5.*:* | i86xen:AuroraUX:5.*:*)
+	GUESS=i386-pc-auroraux$UNAME_RELEASE
+	;;
+    i86pc:SunOS:5.*:* | i86xen:SunOS:5.*:*)
+	set_cc_for_build
+	SUN_ARCH=i386
+	# If there is a compiler, see if it is configured for 64-bit objects.
+	# Note that the Sun cc does not turn __LP64__ into 1 like gcc does.
+	# This test works for both compilers.
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
+	    if (echo '#ifdef __amd64'; echo IS_64BIT_ARCH; echo '#endif') | \
+		(CCOPTS="" $CC_FOR_BUILD -m64 -E - 2>/dev/null) | \
+		grep IS_64BIT_ARCH >/dev/null
+	    then
+		SUN_ARCH=x86_64
+	    fi
+	fi
+	SUN_REL=`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`
+	GUESS=$SUN_ARCH-pc-solaris2$SUN_REL
+	;;
+    sun4*:SunOS:6*:*)
+	# According to config.sub, this is the proper way to canonicalize
+	# SunOS6.  Hard to guess exactly what SunOS6 will be like, but
+	# it's likely to be more like Solaris than SunOS4.
+	SUN_REL=`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`
+	GUESS=sparc-sun-solaris3$SUN_REL
+	;;
+    sun4*:SunOS:*:*)
+	case `/usr/bin/arch -k` in
+	    Series*|S4*)
+		UNAME_RELEASE=`uname -v`
+		;;
+	esac
+	# Japanese Language versions have a version number like '4.1.3-JL'.
+	SUN_REL=`echo "$UNAME_RELEASE" | sed -e 's/-/_/'`
+	GUESS=sparc-sun-sunos$SUN_REL
+	;;
+    sun3*:SunOS:*:*)
+	GUESS=m68k-sun-sunos$UNAME_RELEASE
+	;;
+    sun*:*:4.2BSD:*)
+	UNAME_RELEASE=`(sed 1q /etc/motd | awk '{print substr($5,1,3)}') 2>/dev/null`
+	test "x$UNAME_RELEASE" = x && UNAME_RELEASE=3
+	case `/bin/arch` in
+	    sun3)
+		GUESS=m68k-sun-sunos$UNAME_RELEASE
+		;;
+	    sun4)
+		GUESS=sparc-sun-sunos$UNAME_RELEASE
+		;;
+	esac
+	;;
+    aushp:SunOS:*:*)
+	GUESS=sparc-auspex-sunos$UNAME_RELEASE
+	;;
+    # The situation for MiNT is a little confusing.  The machine name
+    # can be virtually everything (everything which is not
+    # "atarist" or "atariste" at least should have a processor
+    # > m68000).  The system name ranges from "MiNT" over "FreeMiNT"
+    # to the lowercase version "mint" (or "freemint").  Finally
+    # the system name "TOS" denotes a system which is actually not
+    # MiNT.  But MiNT is downward compatible to TOS, so this should
+    # be no problem.
+    atarist[e]:*MiNT:*:* | atarist[e]:*mint:*:* | atarist[e]:*TOS:*:*)
+	GUESS=m68k-atari-mint$UNAME_RELEASE
+	;;
+    atari*:*MiNT:*:* | atari*:*mint:*:* | atarist[e]:*TOS:*:*)
+	GUESS=m68k-atari-mint$UNAME_RELEASE
+	;;
+    *falcon*:*MiNT:*:* | *falcon*:*mint:*:* | *falcon*:*TOS:*:*)
+	GUESS=m68k-atari-mint$UNAME_RELEASE
+	;;
+    milan*:*MiNT:*:* | milan*:*mint:*:* | *milan*:*TOS:*:*)
+	GUESS=m68k-milan-mint$UNAME_RELEASE
+	;;
+    hades*:*MiNT:*:* | hades*:*mint:*:* | *hades*:*TOS:*:*)
+	GUESS=m68k-hades-mint$UNAME_RELEASE
+	;;
+    *:*MiNT:*:* | *:*mint:*:* | *:*TOS:*:*)
+	GUESS=m68k-unknown-mint$UNAME_RELEASE
+	;;
+    m68k:machten:*:*)
+	GUESS=m68k-apple-machten$UNAME_RELEASE
+	;;
+    powerpc:machten:*:*)
+	GUESS=powerpc-apple-machten$UNAME_RELEASE
+	;;
+    RISC*:Mach:*:*)
+	GUESS=mips-dec-mach_bsd4.3
+	;;
+    RISC*:ULTRIX:*:*)
+	GUESS=mips-dec-ultrix$UNAME_RELEASE
+	;;
+    VAX*:ULTRIX*:*:*)
+	GUESS=vax-dec-ultrix$UNAME_RELEASE
+	;;
+    2020:CLIX:*:* | 2430:CLIX:*:*)
+	GUESS=clipper-intergraph-clix$UNAME_RELEASE
+	;;
+    mips:*:*:UMIPS | mips:*:*:RISCos)
+	set_cc_for_build
+	sed 's/^	//' << EOF > "$dummy.c"
+#ifdef __cplusplus
+#include <stdio.h>  /* for printf() prototype */
+	int main (int argc, char *argv[]) {
+#else
+	int main (argc, argv) int argc; char *argv[]; {
+#endif
+	#if defined (host_mips) && defined (MIPSEB)
+	#if defined (SYSTYPE_SYSV)
+	  printf ("mips-mips-riscos%ssysv\\n", argv[1]); exit (0);
+	#endif
+	#if defined (SYSTYPE_SVR4)
+	  printf ("mips-mips-riscos%ssvr4\\n", argv[1]); exit (0);
+	#endif
+	#if defined (SYSTYPE_BSD43) || defined(SYSTYPE_BSD)
+	  printf ("mips-mips-riscos%sbsd\\n", argv[1]); exit (0);
+	#endif
+	#endif
+	  exit (-1);
+	}
+EOF
+	$CC_FOR_BUILD -o "$dummy" "$dummy.c" &&
+	  dummyarg=`echo "$UNAME_RELEASE" | sed -n 's/\([0-9]*\).*/\1/p'` &&
+	  SYSTEM_NAME=`"$dummy" "$dummyarg"` &&
+	    { echo "$SYSTEM_NAME"; exit; }
+	GUESS=mips-mips-riscos$UNAME_RELEASE
+	;;
+    Motorola:PowerMAX_OS:*:*)
+	GUESS=powerpc-motorola-powermax
+	;;
+    Motorola:*:4.3:PL8-*)
+	GUESS=powerpc-harris-powermax
+	;;
+    Night_Hawk:*:*:PowerMAX_OS | Synergy:PowerMAX_OS:*:*)
+	GUESS=powerpc-harris-powermax
+	;;
+    Night_Hawk:Power_UNIX:*:*)
+	GUESS=powerpc-harris-powerunix
+	;;
+    m88k:CX/UX:7*:*)
+	GUESS=m88k-harris-cxux7
+	;;
+    m88k:*:4*:R4*)
+	GUESS=m88k-motorola-sysv4
+	;;
+    m88k:*:3*:R3*)
+	GUESS=m88k-motorola-sysv3
+	;;
+    AViiON:dgux:*:*)
+	# DG/UX returns AViiON for all architectures
+	UNAME_PROCESSOR=`/usr/bin/uname -p`
+	if test "$UNAME_PROCESSOR" = mc88100 || test "$UNAME_PROCESSOR" = mc88110
+	then
+	    if test "$TARGET_BINARY_INTERFACE"x = m88kdguxelfx || \
+	       test "$TARGET_BINARY_INTERFACE"x = x
+	    then
+		GUESS=m88k-dg-dgux$UNAME_RELEASE
+	    else
+		GUESS=m88k-dg-dguxbcs$UNAME_RELEASE
+	    fi
+	else
+	    GUESS=i586-dg-dgux$UNAME_RELEASE
+	fi
+	;;
+    M88*:DolphinOS:*:*)	# DolphinOS (SVR3)
+	GUESS=m88k-dolphin-sysv3
+	;;
+    M88*:*:R3*:*)
+	# Delta 88k system running SVR3
+	GUESS=m88k-motorola-sysv3
+	;;
+    XD88*:*:*:*) # Tektronix XD88 system running UTekV (SVR3)
+	GUESS=m88k-tektronix-sysv3
+	;;
+    Tek43[0-9][0-9]:UTek:*:*) # Tektronix 4300 system running UTek (BSD)
+	GUESS=m68k-tektronix-bsd
+	;;
+    *:IRIX*:*:*)
+	IRIX_REL=`echo "$UNAME_RELEASE" | sed -e 's/-/_/g'`
+	GUESS=mips-sgi-irix$IRIX_REL
+	;;
+    ????????:AIX?:[12].1:2)   # AIX 2.2.1 or AIX 2.1.1 is RT/PC AIX.
+	GUESS=romp-ibm-aix    # uname -m gives an 8 hex-code CPU id
+	;;                    # Note that: echo "'`uname -s`'" gives 'AIX '
+    i*86:AIX:*:*)
+	GUESS=i386-ibm-aix
+	;;
+    ia64:AIX:*:*)
+	if test -x /usr/bin/oslevel ; then
+		IBM_REV=`/usr/bin/oslevel`
+	else
+		IBM_REV=$UNAME_VERSION.$UNAME_RELEASE
+	fi
+	GUESS=$UNAME_MACHINE-ibm-aix$IBM_REV
+	;;
+    *:AIX:2:3)
+	if grep bos325 /usr/include/stdio.h >/dev/null 2>&1; then
+		set_cc_for_build
+		sed 's/^		//' << EOF > "$dummy.c"
+		#include <sys/systemcfg.h>
+
+		main()
+			{
+			if (!__power_pc())
+				exit(1);
+			puts("powerpc-ibm-aix3.2.5");
+			exit(0);
+			}
+EOF
+		if $CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=`"$dummy"`
+		then
+			GUESS=$SYSTEM_NAME
+		else
+			GUESS=rs6000-ibm-aix3.2.5
+		fi
+	elif grep bos324 /usr/include/stdio.h >/dev/null 2>&1; then
+		GUESS=rs6000-ibm-aix3.2.4
+	else
+		GUESS=rs6000-ibm-aix3.2
+	fi
+	;;
+    *:AIX:*:[4567])
+	IBM_CPU_ID=`/usr/sbin/lsdev -C -c processor -S available | sed 1q | awk '{ print $1 }'`
+	if /usr/sbin/lsattr -El "$IBM_CPU_ID" | grep ' POWER' >/dev/null 2>&1; then
+		IBM_ARCH=rs6000
+	else
+		IBM_ARCH=powerpc
+	fi
+	if test -x /usr/bin/lslpp ; then
+		IBM_REV=`/usr/bin/lslpp -Lqc bos.rte.libc | \
+			   awk -F: '{ print $3 }' | sed s/[0-9]*$/0/`
+	else
+		IBM_REV=$UNAME_VERSION.$UNAME_RELEASE
+	fi
+	GUESS=$IBM_ARCH-ibm-aix$IBM_REV
+	;;
+    *:AIX:*:*)
+	GUESS=rs6000-ibm-aix
+	;;
+    ibmrt:4.4BSD:*|romp-ibm:4.4BSD:*)
+	GUESS=romp-ibm-bsd4.4
+	;;
+    ibmrt:*BSD:*|romp-ibm:BSD:*)            # covers RT/PC BSD and
+	GUESS=romp-ibm-bsd$UNAME_RELEASE    # 4.3 with uname added to
+	;;                                  # report: romp-ibm BSD 4.3
+    *:BOSX:*:*)
+	GUESS=rs6000-bull-bosx
+	;;
+    DPX/2?00:B.O.S.:*:*)
+	GUESS=m68k-bull-sysv3
+	;;
+    9000/[34]??:4.3bsd:1.*:*)
+	GUESS=m68k-hp-bsd
+	;;
+    hp300:4.4BSD:*:* | 9000/[34]??:4.3bsd:2.*:*)
+	GUESS=m68k-hp-bsd4.4
+	;;
+    9000/[34678]??:HP-UX:*:*)
+	HPUX_REV=`echo "$UNAME_RELEASE" | sed -e 's/[^.]*.[0B]*//'`
+	case $UNAME_MACHINE in
+	    9000/31?)            HP_ARCH=m68000 ;;
+	    9000/[34]??)         HP_ARCH=m68k ;;
+	    9000/[678][0-9][0-9])
+		if test -x /usr/bin/getconf; then
+		    sc_cpu_version=`/usr/bin/getconf SC_CPU_VERSION 2>/dev/null`
+		    sc_kernel_bits=`/usr/bin/getconf SC_KERNEL_BITS 2>/dev/null`
+		    case $sc_cpu_version in
+		      523) HP_ARCH=hppa1.0 ;; # CPU_PA_RISC1_0
+		      528) HP_ARCH=hppa1.1 ;; # CPU_PA_RISC1_1
+		      532)                      # CPU_PA_RISC2_0
+			case $sc_kernel_bits in
+			  32) HP_ARCH=hppa2.0n ;;
+			  64) HP_ARCH=hppa2.0w ;;
+			  '') HP_ARCH=hppa2.0 ;;   # HP-UX 10.20
+			esac ;;
+		    esac
+		fi
+		if test "$HP_ARCH" = ""; then
+		    set_cc_for_build
+		    sed 's/^		//' << EOF > "$dummy.c"
+
+		#define _HPUX_SOURCE
+		#include <stdlib.h>
+		#include <unistd.h>
+
+		int main ()
+		{
+		#if defined(_SC_KERNEL_BITS)
+		    long bits = sysconf(_SC_KERNEL_BITS);
+		#endif
+		    long cpu  = sysconf (_SC_CPU_VERSION);
+
+		    switch (cpu)
+			{
+			case CPU_PA_RISC1_0: puts ("hppa1.0"); break;
+			case CPU_PA_RISC1_1: puts ("hppa1.1"); break;
+			case CPU_PA_RISC2_0:
+		#if defined(_SC_KERNEL_BITS)
+			    switch (bits)
+				{
+				case 64: puts ("hppa2.0w"); break;
+				case 32: puts ("hppa2.0n"); break;
+				default: puts ("hppa2.0"); break;
+				} break;
+		#else  /* !defined(_SC_KERNEL_BITS) */
+			    puts ("hppa2.0"); break;
+		#endif
+			default: puts ("hppa1.0"); break;
+			}
+		    exit (0);
+		}
+EOF
+		    (CCOPTS="" $CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null) && HP_ARCH=`"$dummy"`
+		    test -z "$HP_ARCH" && HP_ARCH=hppa
+		fi ;;
+	esac
+	if test "$HP_ARCH" = hppa2.0w
+	then
+	    set_cc_for_build
+
+	    # hppa2.0w-hp-hpux* has a 64-bit kernel and a compiler generating
+	    # 32-bit code.  hppa64-hp-hpux* has the same kernel and a compiler
+	    # generating 64-bit code.  GNU and HP use different nomenclature:
+	    #
+	    # $ CC_FOR_BUILD=cc ./config.guess
+	    # => hppa2.0w-hp-hpux11.23
+	    # $ CC_FOR_BUILD="cc +DA2.0w" ./config.guess
+	    # => hppa64-hp-hpux11.23
+
+	    if echo __LP64__ | (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) |
+		grep -q __LP64__
+	    then
+		HP_ARCH=hppa2.0w
+	    else
+		HP_ARCH=hppa64
+	    fi
+	fi
+	GUESS=$HP_ARCH-hp-hpux$HPUX_REV
+	;;
+    ia64:HP-UX:*:*)
+	HPUX_REV=`echo "$UNAME_RELEASE" | sed -e 's/[^.]*.[0B]*//'`
+	GUESS=ia64-hp-hpux$HPUX_REV
+	;;
+    3050*:HI-UX:*:*)
+	set_cc_for_build
+	sed 's/^	//' << EOF > "$dummy.c"
+	#include <unistd.h>
+	int
+	main ()
+	{
+	  long cpu = sysconf (_SC_CPU_VERSION);
+	  /* The order matters, because CPU_IS_HP_MC68K erroneously returns
+	     true for CPU_PA_RISC1_0.  CPU_IS_PA_RISC returns correct
+	     results, however.  */
+	  if (CPU_IS_PA_RISC (cpu))
+	    {
+	      switch (cpu)
+		{
+		  case CPU_PA_RISC1_0: puts ("hppa1.0-hitachi-hiuxwe2"); break;
+		  case CPU_PA_RISC1_1: puts ("hppa1.1-hitachi-hiuxwe2"); break;
+		  case CPU_PA_RISC2_0: puts ("hppa2.0-hitachi-hiuxwe2"); break;
+		  default: puts ("hppa-hitachi-hiuxwe2"); break;
+		}
+	    }
+	  else if (CPU_IS_HP_MC68K (cpu))
+	    puts ("m68k-hitachi-hiuxwe2");
+	  else puts ("unknown-hitachi-hiuxwe2");
+	  exit (0);
+	}
+EOF
+	$CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=`"$dummy"` &&
+		{ echo "$SYSTEM_NAME"; exit; }
+	GUESS=unknown-hitachi-hiuxwe2
+	;;
+    9000/7??:4.3bsd:*:* | 9000/8?[79]:4.3bsd:*:*)
+	GUESS=hppa1.1-hp-bsd
+	;;
+    9000/8??:4.3bsd:*:*)
+	GUESS=hppa1.0-hp-bsd
+	;;
+    *9??*:MPE/iX:*:* | *3000*:MPE/iX:*:*)
+	GUESS=hppa1.0-hp-mpeix
+	;;
+    hp7??:OSF1:*:* | hp8?[79]:OSF1:*:*)
+	GUESS=hppa1.1-hp-osf
+	;;
+    hp8??:OSF1:*:*)
+	GUESS=hppa1.0-hp-osf
+	;;
+    i*86:OSF1:*:*)
+	if test -x /usr/sbin/sysversion ; then
+	    GUESS=$UNAME_MACHINE-unknown-osf1mk
+	else
+	    GUESS=$UNAME_MACHINE-unknown-osf1
+	fi
+	;;
+    parisc*:Lites*:*:*)
+	GUESS=hppa1.1-hp-lites
+	;;
+    C1*:ConvexOS:*:* | convex:ConvexOS:C1*:*)
+	GUESS=c1-convex-bsd
+	;;
+    C2*:ConvexOS:*:* | convex:ConvexOS:C2*:*)
+	if getsysinfo -f scalar_acc
+	then echo c32-convex-bsd
+	else echo c2-convex-bsd
+	fi
+	exit ;;
+    C34*:ConvexOS:*:* | convex:ConvexOS:C34*:*)
+	GUESS=c34-convex-bsd
+	;;
+    C38*:ConvexOS:*:* | convex:ConvexOS:C38*:*)
+	GUESS=c38-convex-bsd
+	;;
+    C4*:ConvexOS:*:* | convex:ConvexOS:C4*:*)
+	GUESS=c4-convex-bsd
+	;;
+    CRAY*Y-MP:*:*:*)
+	CRAY_REL=`echo "$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'`
+	GUESS=ymp-cray-unicos$CRAY_REL
+	;;
+    CRAY*[A-Z]90:*:*:*)
+	echo "$UNAME_MACHINE"-cray-unicos"$UNAME_RELEASE" \
+	| sed -e 's/CRAY.*\([A-Z]90\)/\1/' \
+	      -e y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/ \
+	      -e 's/\.[^.]*$/.X/'
+	exit ;;
+    CRAY*TS:*:*:*)
+	CRAY_REL=`echo "$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'`
+	GUESS=t90-cray-unicos$CRAY_REL
+	;;
+    CRAY*T3E:*:*:*)
+	CRAY_REL=`echo "$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'`
+	GUESS=alphaev5-cray-unicosmk$CRAY_REL
+	;;
+    CRAY*SV1:*:*:*)
+	CRAY_REL=`echo "$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'`
+	GUESS=sv1-cray-unicos$CRAY_REL
+	;;
+    *:UNICOS/mp:*:*)
+	CRAY_REL=`echo "$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'`
+	GUESS=craynv-cray-unicosmp$CRAY_REL
+	;;
+    F30[01]:UNIX_System_V:*:* | F700:UNIX_System_V:*:*)
+	FUJITSU_PROC=`uname -m | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz`
+	FUJITSU_SYS=`uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///'`
+	FUJITSU_REL=`echo "$UNAME_RELEASE" | sed -e 's/ /_/'`
+	GUESS=${FUJITSU_PROC}-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}
+	;;
+    5000:UNIX_System_V:4.*:*)
+	FUJITSU_SYS=`uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///'`
+	FUJITSU_REL=`echo "$UNAME_RELEASE" | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/ /_/'`
+	GUESS=sparc-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}
+	;;
+    i*86:BSD/386:*:* | i*86:BSD/OS:*:* | *:Ascend\ Embedded/OS:*:*)
+	GUESS=$UNAME_MACHINE-pc-bsdi$UNAME_RELEASE
+	;;
+    sparc*:BSD/OS:*:*)
+	GUESS=sparc-unknown-bsdi$UNAME_RELEASE
+	;;
+    *:BSD/OS:*:*)
+	GUESS=$UNAME_MACHINE-unknown-bsdi$UNAME_RELEASE
+	;;
+    arm:FreeBSD:*:*)
+	UNAME_PROCESSOR=`uname -p`
+	set_cc_for_build
+	if echo __ARM_PCS_VFP | $CC_FOR_BUILD -E - 2>/dev/null \
+	    | grep -q __ARM_PCS_VFP
+	then
+	    FREEBSD_REL=`echo "$UNAME_RELEASE" | sed -e 's/[-(].*//'`
+	    GUESS=$UNAME_PROCESSOR-unknown-freebsd$FREEBSD_REL-gnueabi
+	else
+	    FREEBSD_REL=`echo "$UNAME_RELEASE" | sed -e 's/[-(].*//'`
+	    GUESS=$UNAME_PROCESSOR-unknown-freebsd$FREEBSD_REL-gnueabihf
+	fi
+	;;
+    *:FreeBSD:*:*)
+	UNAME_PROCESSOR=`uname -p`
+	case $UNAME_PROCESSOR in
+	    amd64)
+		UNAME_PROCESSOR=x86_64 ;;
+	    i386)
+		UNAME_PROCESSOR=i586 ;;
+	esac
+	FREEBSD_REL=`echo "$UNAME_RELEASE" | sed -e 's/[-(].*//'`
+	GUESS=$UNAME_PROCESSOR-unknown-freebsd$FREEBSD_REL
+	;;
+    i*:CYGWIN*:*)
+	GUESS=$UNAME_MACHINE-pc-cygwin
+	;;
+    *:MINGW64*:*)
+	GUESS=$UNAME_MACHINE-pc-mingw64
+	;;
+    *:MINGW*:*)
+	GUESS=$UNAME_MACHINE-pc-mingw32
+	;;
+    *:MSYS*:*)
+	GUESS=$UNAME_MACHINE-pc-msys
+	;;
+    i*:PW*:*)
+	GUESS=$UNAME_MACHINE-pc-pw32
+	;;
+    *:SerenityOS:*:*)
+        GUESS=$UNAME_MACHINE-pc-serenity
+        ;;
+    *:Interix*:*)
+	case $UNAME_MACHINE in
+	    x86)
+		GUESS=i586-pc-interix$UNAME_RELEASE
+		;;
+	    authenticamd | genuineintel | EM64T)
+		GUESS=x86_64-unknown-interix$UNAME_RELEASE
+		;;
+	    IA64)
+		GUESS=ia64-unknown-interix$UNAME_RELEASE
+		;;
+	esac ;;
+    i*:UWIN*:*)
+	GUESS=$UNAME_MACHINE-pc-uwin
+	;;
+    amd64:CYGWIN*:*:* | x86_64:CYGWIN*:*:*)
+	GUESS=x86_64-pc-cygwin
+	;;
+    prep*:SunOS:5.*:*)
+	SUN_REL=`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`
+	GUESS=powerpcle-unknown-solaris2$SUN_REL
+	;;
+    *:GNU:*:*)
+	# the GNU system
+	GNU_ARCH=`echo "$UNAME_MACHINE" | sed -e 's,[-/].*$,,'`
+	GNU_REL=`echo "$UNAME_RELEASE" | sed -e 's,/.*$,,'`
+	GUESS=$GNU_ARCH-unknown-$LIBC$GNU_REL
+	;;
+    *:GNU/*:*:*)
+	# other systems with GNU libc and userland
+	GNU_SYS=`echo "$UNAME_SYSTEM" | sed 's,^[^/]*/,,' | tr "[:upper:]" "[:lower:]"`
+	GNU_REL=`echo "$UNAME_RELEASE" | sed -e 's/[-(].*//'`
+	GUESS=$UNAME_MACHINE-unknown-$GNU_SYS$GNU_REL-$LIBC
+	;;
+    x86_64:[Mm]anagarm:*:*|i?86:[Mm]anagarm:*:*)
+	GUESS="$UNAME_MACHINE-pc-managarm-mlibc"
+	;;
+    *:[Mm]anagarm:*:*)
+	GUESS="$UNAME_MACHINE-unknown-managarm-mlibc"
+	;;
+    *:Minix:*:*)
+	GUESS=$UNAME_MACHINE-unknown-minix
+	;;
+    aarch64:Linux:*:*)
+	set_cc_for_build
+	CPU=$UNAME_MACHINE
+	LIBCABI=$LIBC
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
+	    ABI=64
+	    sed 's/^	    //' << EOF > "$dummy.c"
+	    #ifdef __ARM_EABI__
+	    #ifdef __ARM_PCS_VFP
+	    ABI=eabihf
+	    #else
+	    ABI=eabi
+	    #endif
+	    #endif
+EOF
+	    cc_set_abi=`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^ABI' | sed 's, ,,g'`
+	    eval "$cc_set_abi"
+	    case $ABI in
+		eabi | eabihf) CPU=armv8l; LIBCABI=$LIBC$ABI ;;
+	    esac
+	fi
+	GUESS=$CPU-unknown-linux-$LIBCABI
+	;;
+    aarch64_be:Linux:*:*)
+	UNAME_MACHINE=aarch64_be
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    alpha:Linux:*:*)
+	case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' /proc/cpuinfo 2>/dev/null` in
+	  EV5)   UNAME_MACHINE=alphaev5 ;;
+	  EV56)  UNAME_MACHINE=alphaev56 ;;
+	  PCA56) UNAME_MACHINE=alphapca56 ;;
+	  PCA57) UNAME_MACHINE=alphapca56 ;;
+	  EV6)   UNAME_MACHINE=alphaev6 ;;
+	  EV67)  UNAME_MACHINE=alphaev67 ;;
+	  EV68*) UNAME_MACHINE=alphaev68 ;;
+	esac
+	objdump --private-headers /bin/sh | grep -q ld.so.1
+	if test "$?" = 0 ; then LIBC=gnulibc1 ; fi
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    arc:Linux:*:* | arceb:Linux:*:* | arc32:Linux:*:* | arc64:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    arm*:Linux:*:*)
+	set_cc_for_build
+	if echo __ARM_EABI__ | $CC_FOR_BUILD -E - 2>/dev/null \
+	    | grep -q __ARM_EABI__
+	then
+	    GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	else
+	    if echo __ARM_PCS_VFP | $CC_FOR_BUILD -E - 2>/dev/null \
+		| grep -q __ARM_PCS_VFP
+	    then
+		GUESS=$UNAME_MACHINE-unknown-linux-${LIBC}eabi
+	    else
+		GUESS=$UNAME_MACHINE-unknown-linux-${LIBC}eabihf
+	    fi
+	fi
+	;;
+    avr32*:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    cris:Linux:*:*)
+	GUESS=$UNAME_MACHINE-axis-linux-$LIBC
+	;;
+    crisv32:Linux:*:*)
+	GUESS=$UNAME_MACHINE-axis-linux-$LIBC
+	;;
+    e2k:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    frv:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    hexagon:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    i*86:Linux:*:*)
+	GUESS=$UNAME_MACHINE-pc-linux-$LIBC
+	;;
+    ia64:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    k1om:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    kvx:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    kvx:cos:*:*)
+	GUESS=$UNAME_MACHINE-unknown-cos
+	;;
+    kvx:mbr:*:*)
+	GUESS=$UNAME_MACHINE-unknown-mbr
+	;;
+    loongarch32:Linux:*:* | loongarch64:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    m32r*:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    m68*:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    mips:Linux:*:* | mips64:Linux:*:*)
+	set_cc_for_build
+	IS_GLIBC=0
+	test x"${LIBC}" = xgnu && IS_GLIBC=1
+	sed 's/^	//' << EOF > "$dummy.c"
+	#undef CPU
+	#undef mips
+	#undef mipsel
+	#undef mips64
+	#undef mips64el
+	#if ${IS_GLIBC} && defined(_ABI64)
+	LIBCABI=gnuabi64
+	#else
+	#if ${IS_GLIBC} && defined(_ABIN32)
+	LIBCABI=gnuabin32
+	#else
+	LIBCABI=${LIBC}
+	#endif
+	#endif
+
+	#if ${IS_GLIBC} && defined(__mips64) && defined(__mips_isa_rev) && __mips_isa_rev>=6
+	CPU=mipsisa64r6
+	#else
+	#if ${IS_GLIBC} && !defined(__mips64) && defined(__mips_isa_rev) && __mips_isa_rev>=6
+	CPU=mipsisa32r6
+	#else
+	#if defined(__mips64)
+	CPU=mips64
+	#else
+	CPU=mips
+	#endif
+	#endif
+	#endif
+
+	#if defined(__MIPSEL__) || defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL)
+	MIPS_ENDIAN=el
+	#else
+	#if defined(__MIPSEB__) || defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB)
+	MIPS_ENDIAN=
+	#else
+	MIPS_ENDIAN=
+	#endif
+	#endif
+EOF
+	cc_set_vars=`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^CPU\|^MIPS_ENDIAN\|^LIBCABI'`
+	eval "$cc_set_vars"
+	test "x$CPU" != x && { echo "$CPU${MIPS_ENDIAN}-unknown-linux-$LIBCABI"; exit; }
+	;;
+    mips64el:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    openrisc*:Linux:*:*)
+	GUESS=or1k-unknown-linux-$LIBC
+	;;
+    or32:Linux:*:* | or1k*:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    padre:Linux:*:*)
+	GUESS=sparc-unknown-linux-$LIBC
+	;;
+    parisc64:Linux:*:* | hppa64:Linux:*:*)
+	GUESS=hppa64-unknown-linux-$LIBC
+	;;
+    parisc:Linux:*:* | hppa:Linux:*:*)
+	# Look for CPU level
+	case `grep '^cpu[^a-z]*:' /proc/cpuinfo 2>/dev/null | cut -d' ' -f2` in
+	  PA7*) GUESS=hppa1.1-unknown-linux-$LIBC ;;
+	  PA8*) GUESS=hppa2.0-unknown-linux-$LIBC ;;
+	  *)    GUESS=hppa-unknown-linux-$LIBC ;;
+	esac
+	;;
+    ppc64:Linux:*:*)
+	GUESS=powerpc64-unknown-linux-$LIBC
+	;;
+    ppc:Linux:*:*)
+	GUESS=powerpc-unknown-linux-$LIBC
+	;;
+    ppc64le:Linux:*:*)
+	GUESS=powerpc64le-unknown-linux-$LIBC
+	;;
+    ppcle:Linux:*:*)
+	GUESS=powerpcle-unknown-linux-$LIBC
+	;;
+    riscv32:Linux:*:* | riscv32be:Linux:*:* | riscv64:Linux:*:* | riscv64be:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    s390:Linux:*:* | s390x:Linux:*:*)
+	GUESS=$UNAME_MACHINE-ibm-linux-$LIBC
+	;;
+    sh64*:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    sh*:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    sparc:Linux:*:* | sparc64:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    tile*:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    vax:Linux:*:*)
+	GUESS=$UNAME_MACHINE-dec-linux-$LIBC
+	;;
+    x86_64:Linux:*:*)
+	set_cc_for_build
+	CPU=$UNAME_MACHINE
+	LIBCABI=$LIBC
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
+	    ABI=64
+	    sed 's/^	    //' << EOF > "$dummy.c"
+	    #ifdef __i386__
+	    ABI=x86
+	    #else
+	    #ifdef __ILP32__
+	    ABI=x32
+	    #endif
+	    #endif
+EOF
+	    cc_set_abi=`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^ABI' | sed 's, ,,g'`
+	    eval "$cc_set_abi"
+	    case $ABI in
+		x86) CPU=i686 ;;
+		x32) LIBCABI=${LIBC}x32 ;;
+	    esac
+	fi
+	GUESS=$CPU-pc-linux-$LIBCABI
+	;;
+    xtensa*:Linux:*:*)
+	GUESS=$UNAME_MACHINE-unknown-linux-$LIBC
+	;;
+    i*86:DYNIX/ptx:4*:*)
+	# ptx 4.0 does uname -s correctly, with DYNIX/ptx in there.
+	# earlier versions are messed up and put the nodename in both
+	# sysname and nodename.
+	GUESS=i386-sequent-sysv4
+	;;
+    i*86:UNIX_SV:4.2MP:2.*)
+	# Unixware is an offshoot of SVR4, but it has its own version
+	# number series starting with 2...
+	# I am not positive that other SVR4 systems won't match this,
+	# I just have to hope.  -- rms.
+	# Use sysv4.2uw... so that sysv4* matches it.
+	GUESS=$UNAME_MACHINE-pc-sysv4.2uw$UNAME_VERSION
+	;;
+    i*86:OS/2:*:*)
+	# If we were able to find 'uname', then EMX Unix compatibility
+	# is probably installed.
+	GUESS=$UNAME_MACHINE-pc-os2-emx
+	;;
+    i*86:XTS-300:*:STOP)
+	GUESS=$UNAME_MACHINE-unknown-stop
+	;;
+    i*86:atheos:*:*)
+	GUESS=$UNAME_MACHINE-unknown-atheos
+	;;
+    i*86:syllable:*:*)
+	GUESS=$UNAME_MACHINE-pc-syllable
+	;;
+    i*86:LynxOS:2.*:* | i*86:LynxOS:3.[01]*:* | i*86:LynxOS:4.[02]*:*)
+	GUESS=i386-unknown-lynxos$UNAME_RELEASE
+	;;
+    i*86:*DOS:*:*)
+	GUESS=$UNAME_MACHINE-pc-msdosdjgpp
+	;;
+    i*86:*:4.*:*)
+	UNAME_REL=`echo "$UNAME_RELEASE" | sed 's/\/MP$//'`
+	if grep Novell /usr/include/link.h >/dev/null 2>/dev/null; then
+		GUESS=$UNAME_MACHINE-univel-sysv$UNAME_REL
+	else
+		GUESS=$UNAME_MACHINE-pc-sysv$UNAME_REL
+	fi
+	;;
+    i*86:*:5:[678]*)
+	# UnixWare 7.x, OpenUNIX and OpenServer 6.
+	case `/bin/uname -X | grep "^Machine"` in
+	    *486*)	     UNAME_MACHINE=i486 ;;
+	    *Pentium)	     UNAME_MACHINE=i586 ;;
+	    *Pent*|*Celeron) UNAME_MACHINE=i686 ;;
+	esac
+	GUESS=$UNAME_MACHINE-unknown-sysv${UNAME_RELEASE}${UNAME_SYSTEM}${UNAME_VERSION}
+	;;
+    i*86:*:3.2:*)
+	if test -f /usr/options/cb.name; then
+		UNAME_REL=`sed -n 's/.*Version //p' </usr/options/cb.name`
+		GUESS=$UNAME_MACHINE-pc-isc$UNAME_REL
+	elif /bin/uname -X 2>/dev/null >/dev/null ; then
+		UNAME_REL=`(/bin/uname -X|grep Release|sed -e 's/.*= //')`
+		(/bin/uname -X|grep i80486 >/dev/null) && UNAME_MACHINE=i486
+		(/bin/uname -X|grep '^Machine.*Pentium' >/dev/null) \
+			&& UNAME_MACHINE=i586
+		(/bin/uname -X|grep '^Machine.*Pent *II' >/dev/null) \
+			&& UNAME_MACHINE=i686
+		(/bin/uname -X|grep '^Machine.*Pentium Pro' >/dev/null) \
+			&& UNAME_MACHINE=i686
+		GUESS=$UNAME_MACHINE-pc-sco$UNAME_REL
+	else
+		GUESS=$UNAME_MACHINE-pc-sysv32
+	fi
+	;;
+    pc:*:*:*)
+	# Left here for compatibility:
+	# uname -m prints for DJGPP always 'pc', but it prints nothing about
+	# the processor, so we play safe by assuming i586.
+	# Note: whatever this is, it MUST be the same as what config.sub
+	# prints for the "djgpp" host, or else GDB configure will decide that
+	# this is a cross-build.
+	GUESS=i586-pc-msdosdjgpp
+	;;
+    Intel:Mach:3*:*)
+	GUESS=i386-pc-mach3
+	;;
+    paragon:*:*:*)
+	GUESS=i860-intel-osf1
+	;;
+    i860:*:4.*:*) # i860-SVR4
+	if grep Stardent /usr/include/sys/uadmin.h >/dev/null 2>&1 ; then
+	  GUESS=i860-stardent-sysv$UNAME_RELEASE    # Stardent Vistra i860-SVR4
+	else # Add other i860-SVR4 vendors below as they are discovered.
+	  GUESS=i860-unknown-sysv$UNAME_RELEASE     # Unknown i860-SVR4
+	fi
+	;;
+    mini*:CTIX:SYS*5:*)
+	# "miniframe"
+	GUESS=m68010-convergent-sysv
+	;;
+    mc68k:UNIX:SYSTEM5:3.51m)
+	GUESS=m68k-convergent-sysv
+	;;
+    M680?0:D-NIX:5.3:*)
+	GUESS=m68k-diab-dnix
+	;;
+    M68*:*:R3V[5678]*:*)
+	test -r /sysV68 && { echo 'm68k-motorola-sysv'; exit; } ;;
+    3[345]??:*:4.0:3.0 | 3[34]??A:*:4.0:3.0 | 3[34]??,*:*:4.0:3.0 | 3[34]??/*:*:4.0:3.0 | 4400:*:4.0:3.0 | 4850:*:4.0:3.0 | SKA40:*:4.0:3.0 | SDS2:*:4.0:3.0 | SHG2:*:4.0:3.0 | S7501*:*:4.0:3.0)
+	OS_REL=''
+	test -r /etc/.relid \
+	&& OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
+	  && { echo i486-ncr-sysv4.3"$OS_REL"; exit; }
+	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
+	  && { echo i586-ncr-sysv4.3"$OS_REL"; exit; } ;;
+    3[34]??:*:4.0:* | 3[34]??,*:*:4.0:*)
+	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
+	  && { echo i486-ncr-sysv4; exit; } ;;
+    NCR*:*:4.2:* | MPRAS*:*:4.2:*)
+	OS_REL='.3'
+	test -r /etc/.relid \
+	    && OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
+	    && { echo i486-ncr-sysv4.3"$OS_REL"; exit; }
+	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
+	    && { echo i586-ncr-sysv4.3"$OS_REL"; exit; }
+	/bin/uname -p 2>/dev/null | /bin/grep pteron >/dev/null \
+	    && { echo i586-ncr-sysv4.3"$OS_REL"; exit; } ;;
+    m68*:LynxOS:2.*:* | m68*:LynxOS:3.0*:*)
+	GUESS=m68k-unknown-lynxos$UNAME_RELEASE
+	;;
+    mc68030:UNIX_System_V:4.*:*)
+	GUESS=m68k-atari-sysv4
+	;;
+    TSUNAMI:LynxOS:2.*:*)
+	GUESS=sparc-unknown-lynxos$UNAME_RELEASE
+	;;
+    rs6000:LynxOS:2.*:*)
+	GUESS=rs6000-unknown-lynxos$UNAME_RELEASE
+	;;
+    PowerPC:LynxOS:2.*:* | PowerPC:LynxOS:3.[01]*:* | PowerPC:LynxOS:4.[02]*:*)
+	GUESS=powerpc-unknown-lynxos$UNAME_RELEASE
+	;;
+    SM[BE]S:UNIX_SV:*:*)
+	GUESS=mips-dde-sysv$UNAME_RELEASE
+	;;
+    RM*:ReliantUNIX-*:*:*)
+	GUESS=mips-sni-sysv4
+	;;
+    RM*:SINIX-*:*:*)
+	GUESS=mips-sni-sysv4
+	;;
+    *:SINIX-*:*:*)
+	if uname -p 2>/dev/null >/dev/null ; then
+		UNAME_MACHINE=`(uname -p) 2>/dev/null`
+		GUESS=$UNAME_MACHINE-sni-sysv4
+	else
+		GUESS=ns32k-sni-sysv
+	fi
+	;;
+    PENTIUM:*:4.0*:*)	# Unisys 'ClearPath HMP IX 4000' SVR4/MP effort
+			# says <Richard.M.Bartel@ccMail.Census.GOV>
+	GUESS=i586-unisys-sysv4
+	;;
+    *:UNIX_System_V:4*:FTX*)
+	# From Gerald Hewes <hewes@openmarket.com>.
+	# How about differentiating between stratus architectures? -djm
+	GUESS=hppa1.1-stratus-sysv4
+	;;
+    *:*:*:FTX*)
+	# From seanf@swdc.stratus.com.
+	GUESS=i860-stratus-sysv4
+	;;
+    i*86:VOS:*:*)
+	# From Paul.Green@stratus.com.
+	GUESS=$UNAME_MACHINE-stratus-vos
+	;;
+    *:VOS:*:*)
+	# From Paul.Green@stratus.com.
+	GUESS=hppa1.1-stratus-vos
+	;;
+    mc68*:A/UX:*:*)
+	GUESS=m68k-apple-aux$UNAME_RELEASE
+	;;
+    news*:NEWS-OS:6*:*)
+	GUESS=mips-sony-newsos6
+	;;
+    R[34]000:*System_V*:*:* | R4000:UNIX_SYSV:*:* | R*000:UNIX_SV:*:*)
+	if test -d /usr/nec; then
+		GUESS=mips-nec-sysv$UNAME_RELEASE
+	else
+		GUESS=mips-unknown-sysv$UNAME_RELEASE
+	fi
+	;;
+    BeBox:BeOS:*:*)	# BeOS running on hardware made by Be, PPC only.
+	GUESS=powerpc-be-beos
+	;;
+    BeMac:BeOS:*:*)	# BeOS running on Mac or Mac clone, PPC only.
+	GUESS=powerpc-apple-beos
+	;;
+    BePC:BeOS:*:*)	# BeOS running on Intel PC compatible.
+	GUESS=i586-pc-beos
+	;;
+    BePC:Haiku:*:*)	# Haiku running on Intel PC compatible.
+	GUESS=i586-pc-haiku
+	;;
+    ppc:Haiku:*:*)	# Haiku running on Apple PowerPC
+	GUESS=powerpc-apple-haiku
+	;;
+    *:Haiku:*:*)	# Haiku modern gcc (not bound by BeOS compat)
+	GUESS=$UNAME_MACHINE-unknown-haiku
+	;;
+    SX-4:SUPER-UX:*:*)
+	GUESS=sx4-nec-superux$UNAME_RELEASE
+	;;
+    SX-5:SUPER-UX:*:*)
+	GUESS=sx5-nec-superux$UNAME_RELEASE
+	;;
+    SX-6:SUPER-UX:*:*)
+	GUESS=sx6-nec-superux$UNAME_RELEASE
+	;;
+    SX-7:SUPER-UX:*:*)
+	GUESS=sx7-nec-superux$UNAME_RELEASE
+	;;
+    SX-8:SUPER-UX:*:*)
+	GUESS=sx8-nec-superux$UNAME_RELEASE
+	;;
+    SX-8R:SUPER-UX:*:*)
+	GUESS=sx8r-nec-superux$UNAME_RELEASE
+	;;
+    SX-ACE:SUPER-UX:*:*)
+	GUESS=sxace-nec-superux$UNAME_RELEASE
+	;;
+    Power*:Rhapsody:*:*)
+	GUESS=powerpc-apple-rhapsody$UNAME_RELEASE
+	;;
+    *:Rhapsody:*:*)
+	GUESS=$UNAME_MACHINE-apple-rhapsody$UNAME_RELEASE
+	;;
+    arm64:Darwin:*:*)
+	GUESS=aarch64-apple-darwin$UNAME_RELEASE
+	;;
+    *:Darwin:*:*)
+	UNAME_PROCESSOR=`uname -p`
+	case $UNAME_PROCESSOR in
+	    unknown) UNAME_PROCESSOR=powerpc ;;
+	esac
+	if command -v xcode-select > /dev/null 2> /dev/null && \
+		! xcode-select --print-path > /dev/null 2> /dev/null ; then
+	    # Avoid executing cc if there is no toolchain installed as
+	    # cc will be a stub that puts up a graphical alert
+	    # prompting the user to install developer tools.
+	    CC_FOR_BUILD=no_compiler_found
+	else
+	    set_cc_for_build
+	fi
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
+	    if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
+		   (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		   grep IS_64BIT_ARCH >/dev/null
+	    then
+		case $UNAME_PROCESSOR in
+		    i386) UNAME_PROCESSOR=x86_64 ;;
+		    powerpc) UNAME_PROCESSOR=powerpc64 ;;
+		esac
+	    fi
+	    # On 10.4-10.6 one might compile for PowerPC via gcc -arch ppc
+	    if (echo '#ifdef __POWERPC__'; echo IS_PPC; echo '#endif') | \
+		   (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		   grep IS_PPC >/dev/null
+	    then
+		UNAME_PROCESSOR=powerpc
+	    fi
+	elif test "$UNAME_PROCESSOR" = i386 ; then
+	    # uname -m returns i386 or x86_64
+	    UNAME_PROCESSOR=$UNAME_MACHINE
+	fi
+	GUESS=$UNAME_PROCESSOR-apple-darwin$UNAME_RELEASE
+	;;
+    *:procnto*:*:* | *:QNX:[0123456789]*:*)
+	UNAME_PROCESSOR=`uname -p`
+	if test "$UNAME_PROCESSOR" = x86; then
+		UNAME_PROCESSOR=i386
+		UNAME_MACHINE=pc
+	fi
+	GUESS=$UNAME_PROCESSOR-$UNAME_MACHINE-nto-qnx$UNAME_RELEASE
+	;;
+    *:QNX:*:4*)
+	GUESS=i386-pc-qnx
+	;;
+    NEO-*:NONSTOP_KERNEL:*:*)
+	GUESS=neo-tandem-nsk$UNAME_RELEASE
+	;;
+    NSE-*:NONSTOP_KERNEL:*:*)
+	GUESS=nse-tandem-nsk$UNAME_RELEASE
+	;;
+    NSR-*:NONSTOP_KERNEL:*:*)
+	GUESS=nsr-tandem-nsk$UNAME_RELEASE
+	;;
+    NSV-*:NONSTOP_KERNEL:*:*)
+	GUESS=nsv-tandem-nsk$UNAME_RELEASE
+	;;
+    NSX-*:NONSTOP_KERNEL:*:*)
+	GUESS=nsx-tandem-nsk$UNAME_RELEASE
+	;;
+    *:NonStop-UX:*:*)
+	GUESS=mips-compaq-nonstopux
+	;;
+    BS2000:POSIX*:*:*)
+	GUESS=bs2000-siemens-sysv
+	;;
+    DS/*:UNIX_System_V:*:*)
+	GUESS=$UNAME_MACHINE-$UNAME_SYSTEM-$UNAME_RELEASE
+	;;
+    *:Plan9:*:*)
+	# "uname -m" is not consistent, so use $cputype instead. 386
+	# is converted to i386 for consistency with other x86
+	# operating systems.
+	if test "${cputype-}" = 386; then
+	    UNAME_MACHINE=i386
+	elif test "x${cputype-}" != x; then
+	    UNAME_MACHINE=$cputype
+	fi
+	GUESS=$UNAME_MACHINE-unknown-plan9
+	;;
+    *:TOPS-10:*:*)
+	GUESS=pdp10-unknown-tops10
+	;;
+    *:TENEX:*:*)
+	GUESS=pdp10-unknown-tenex
+	;;
+    KS10:TOPS-20:*:* | KL10:TOPS-20:*:* | TYPE4:TOPS-20:*:*)
+	GUESS=pdp10-dec-tops20
+	;;
+    XKL-1:TOPS-20:*:* | TYPE5:TOPS-20:*:*)
+	GUESS=pdp10-xkl-tops20
+	;;
+    *:TOPS-20:*:*)
+	GUESS=pdp10-unknown-tops20
+	;;
+    *:ITS:*:*)
+	GUESS=pdp10-unknown-its
+	;;
+    SEI:*:*:SEIUX)
+	GUESS=mips-sei-seiux$UNAME_RELEASE
+	;;
+    *:DragonFly:*:*)
+	DRAGONFLY_REL=`echo "$UNAME_RELEASE" | sed -e 's/[-(].*//'`
+	GUESS=$UNAME_MACHINE-unknown-dragonfly$DRAGONFLY_REL
+	;;
+    *:*VMS:*:*)
+	UNAME_MACHINE=`(uname -p) 2>/dev/null`
+	case $UNAME_MACHINE in
+	    A*) GUESS=alpha-dec-vms ;;
+	    I*) GUESS=ia64-dec-vms ;;
+	    V*) GUESS=vax-dec-vms ;;
+	esac ;;
+    *:XENIX:*:SysV)
+	GUESS=i386-pc-xenix
+	;;
+    i*86:skyos:*:*)
+	SKYOS_REL=`echo "$UNAME_RELEASE" | sed -e 's/ .*$//'`
+	GUESS=$UNAME_MACHINE-pc-skyos$SKYOS_REL
+	;;
+    i*86:rdos:*:*)
+	GUESS=$UNAME_MACHINE-pc-rdos
+	;;
+    i*86:Fiwix:*:*)
+	GUESS=$UNAME_MACHINE-pc-fiwix
+	;;
+    *:AROS:*:*)
+	GUESS=$UNAME_MACHINE-unknown-aros
+	;;
+    x86_64:VMkernel:*:*)
+	GUESS=$UNAME_MACHINE-unknown-esx
+	;;
+    amd64:Isilon\ OneFS:*:*)
+	GUESS=x86_64-unknown-onefs
+	;;
+    *:Unleashed:*:*)
+	GUESS=$UNAME_MACHINE-unknown-unleashed$UNAME_RELEASE
+	;;
+esac
+
+# Do we have a guess based on uname results?
+if test "x$GUESS" != x; then
+    echo "$GUESS"
+    exit
+fi
+
+# No uname command or uname output not recognized.
+set_cc_for_build
+cat > "$dummy.c" <<EOF
+#ifdef _SEQUENT_
+#include <sys/types.h>
+#include <sys/utsname.h>
+#endif
+#if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || defined(__ultrix__)
+#if defined (vax) || defined (__vax) || defined (__vax__) || defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)
+#include <signal.h>
+#if defined(_SIZE_T_) || defined(SIGLOST)
+#include <sys/utsname.h>
+#endif
+#endif
+#endif
+main ()
+{
+#if defined (sony)
+#if defined (MIPSEB)
+  /* BFD wants "bsd" instead of "newsos".  Perhaps BFD should be changed,
+     I don't know....  */
+  printf ("mips-sony-bsd\n"); exit (0);
+#else
+#include <sys/param.h>
+  printf ("m68k-sony-newsos%s\n",
+#ifdef NEWSOS4
+  "4"
+#else
+  ""
+#endif
+  ); exit (0);
+#endif
+#endif
+
+#if defined (NeXT)
+#if !defined (__ARCHITECTURE__)
+#define __ARCHITECTURE__ "m68k"
+#endif
+  int version;
+  version=`(hostinfo | sed -n 's/.*NeXT Mach \([0-9]*\).*/\1/p') 2>/dev/null`;
+  if (version < 4)
+    printf ("%s-next-nextstep%d\n", __ARCHITECTURE__, version);
+  else
+    printf ("%s-next-openstep%d\n", __ARCHITECTURE__, version);
+  exit (0);
+#endif
+
+#if defined (MULTIMAX) || defined (n16)
+#if defined (UMAXV)
+  printf ("ns32k-encore-sysv\n"); exit (0);
+#else
+#if defined (CMU)
+  printf ("ns32k-encore-mach\n"); exit (0);
+#else
+  printf ("ns32k-encore-bsd\n"); exit (0);
+#endif
+#endif
+#endif
+
+#if defined (__386BSD__)
+  printf ("i386-pc-bsd\n"); exit (0);
+#endif
+
+#if defined (sequent)
+#if defined (i386)
+  printf ("i386-sequent-dynix\n"); exit (0);
+#endif
+#if defined (ns32000)
+  printf ("ns32k-sequent-dynix\n"); exit (0);
+#endif
+#endif
+
+#if defined (_SEQUENT_)
+  struct utsname un;
+
+  uname(&un);
+  if (strncmp(un.version, "V2", 2) == 0) {
+    printf ("i386-sequent-ptx2\n"); exit (0);
+  }
+  if (strncmp(un.version, "V1", 2) == 0) { /* XXX is V1 correct? */
+    printf ("i386-sequent-ptx1\n"); exit (0);
+  }
+  printf ("i386-sequent-ptx\n"); exit (0);
+#endif
+
+#if defined (vax)
+#if !defined (ultrix)
+#include <sys/param.h>
+#if defined (BSD)
+#if BSD == 43
+  printf ("vax-dec-bsd4.3\n"); exit (0);
+#else
+#if BSD == 199006
+  printf ("vax-dec-bsd4.3reno\n"); exit (0);
+#else
+  printf ("vax-dec-bsd\n"); exit (0);
+#endif
+#endif
+#else
+  printf ("vax-dec-bsd\n"); exit (0);
+#endif
+#else
+#if defined(_SIZE_T_) || defined(SIGLOST)
+  struct utsname un;
+  uname (&un);
+  printf ("vax-dec-ultrix%s\n", un.release); exit (0);
+#else
+  printf ("vax-dec-ultrix\n"); exit (0);
+#endif
+#endif
+#endif
+#if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || defined(__ultrix__)
+#if defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)
+#if defined(_SIZE_T_) || defined(SIGLOST)
+  struct utsname *un;
+  uname (&un);
+  printf ("mips-dec-ultrix%s\n", un.release); exit (0);
+#else
+  printf ("mips-dec-ultrix\n"); exit (0);
+#endif
+#endif
+#endif
+
+#if defined (alliant) && defined (i860)
+  printf ("i860-alliant-bsd\n"); exit (0);
+#endif
+
+  exit (1);
+}
+EOF
+
+$CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null && SYSTEM_NAME=`"$dummy"` &&
+	{ echo "$SYSTEM_NAME"; exit; }
+
+# Apollos put the system type in the environment.
+test -d /usr/apollo && { echo "$ISP-apollo-$SYSTYPE"; exit; }
+
+echo "$0: unable to guess system type" >&2
+
+case $UNAME_MACHINE:$UNAME_SYSTEM in
+    mips:Linux | mips64:Linux)
+	# If we got here on MIPS GNU/Linux, output extra information.
+	cat >&2 <<EOF
+
+NOTE: MIPS GNU/Linux systems require a C compiler to fully recognize
+the system type. Please install a C compiler and try again.
+EOF
+	;;
+esac
+
+cat >&2 <<EOF
+
+This script (version $timestamp), has failed to recognize the
+operating system you are using. If your script is old, overwrite *all*
+copies of config.guess and config.sub with the latest versions from:
+
+  https://git.savannah.gnu.org/cgit/config.git/plain/config.guess
+and
+  https://git.savannah.gnu.org/cgit/config.git/plain/config.sub
+EOF
+
+our_year=`echo $timestamp | sed 's,-.*,,'`
+thisyear=`date +%Y`
+# shellcheck disable=SC2003
+script_age=`expr "$thisyear" - "$our_year"`
+if test "$script_age" -lt 3 ; then
+   cat >&2 <<EOF
+
+If $0 has already been updated, send the following data and any
+information you think might be pertinent to config-patches@gnu.org to
+provide the necessary information to handle your system.
+
+config.guess timestamp = $timestamp
+
+uname -m = `(uname -m) 2>/dev/null || echo unknown`
+uname -r = `(uname -r) 2>/dev/null || echo unknown`
+uname -s = `(uname -s) 2>/dev/null || echo unknown`
+uname -v = `(uname -v) 2>/dev/null || echo unknown`
+
+/usr/bin/uname -p = `(/usr/bin/uname -p) 2>/dev/null`
+/bin/uname -X     = `(/bin/uname -X) 2>/dev/null`
+
+hostinfo               = `(hostinfo) 2>/dev/null`
+/bin/universe          = `(/bin/universe) 2>/dev/null`
+/usr/bin/arch -k       = `(/usr/bin/arch -k) 2>/dev/null`
+/bin/arch              = `(/bin/arch) 2>/dev/null`
+/usr/bin/oslevel       = `(/usr/bin/oslevel) 2>/dev/null`
+/usr/convex/getsysinfo = `(/usr/convex/getsysinfo) 2>/dev/null`
+
+UNAME_MACHINE = "$UNAME_MACHINE"
+UNAME_RELEASE = "$UNAME_RELEASE"
+UNAME_SYSTEM  = "$UNAME_SYSTEM"
+UNAME_VERSION = "$UNAME_VERSION"
+EOF
+fi
+
+exit 1
+
+# Local variables:
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "timestamp='"
+# time-stamp-format: "%:y-%02m-%02d"
+# time-stamp-end: "'"
+# End:
Index: /trunk/src/libs/libpng-1.6.45/config.h.in
===================================================================
--- /trunk/src/libs/libpng-1.6.45/config.h.in	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/config.h.in	(revision 107811)
@@ -0,0 +1,135 @@
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#undef HAVE_DLFCN_H
+
+/* Define to 1 if you have the 'feenableexcept' function. */
+#undef HAVE_FEENABLEEXCEPT
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#undef HAVE_INTTYPES_H
+
+/* Define to 1 if you have the 'm' library (-lm). */
+#undef HAVE_LIBM
+
+/* Define to 1 if you have the 'z' library (-lz). */
+#undef HAVE_LIBZ
+
+/* Define to 1 if you have the 'pow' function. */
+#undef HAVE_POW
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#undef HAVE_STDINT_H
+
+/* Define to 1 if you have the <stdio.h> header file. */
+#undef HAVE_STDIO_H
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#undef HAVE_STDLIB_H
+
+/* Define to 1 if you have the <strings.h> header file. */
+#undef HAVE_STRINGS_H
+
+/* Define to 1 if you have the <string.h> header file. */
+#undef HAVE_STRING_H
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#undef HAVE_SYS_STAT_H
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#undef HAVE_SYS_TYPES_H
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#undef HAVE_UNISTD_H
+
+/* Define to the sub-directory where libtool stores uninstalled libraries. */
+#undef LT_OBJDIR
+
+/* Name of package */
+#undef PACKAGE
+
+/* Define to the address where bug reports for this package should be sent. */
+#undef PACKAGE_BUGREPORT
+
+/* Define to the full name of this package. */
+#undef PACKAGE_NAME
+
+/* Define to the full name and version of this package. */
+#undef PACKAGE_STRING
+
+/* Define to the one symbol short name of this package. */
+#undef PACKAGE_TARNAME
+
+/* Define to the home page for this package. */
+#undef PACKAGE_URL
+
+/* Define to the version of this package. */
+#undef PACKAGE_VERSION
+
+/* Turn on ARM Neon optimizations at run-time */
+#undef PNG_ARM_NEON_API_SUPPORTED
+
+/* Check for ARM Neon support at run-time */
+#undef PNG_ARM_NEON_CHECK_SUPPORTED
+
+/* Enable ARM Neon optimizations */
+#undef PNG_ARM_NEON_OPT
+
+/* Enable Intel SSE optimizations */
+#undef PNG_INTEL_SSE_OPT
+
+/* Enable LOONGARCH LSX optimizations */
+#undef PNG_LOONGARCH_LSX_OPT
+
+/* Turn on MIPS MMI optimizations at run-time */
+#undef PNG_MIPS_MMI_API_SUPPORTED
+
+/* Check for MIPS MMI support at run-time */
+#undef PNG_MIPS_MMI_CHECK_SUPPORTED
+
+/* Enable MIPS MMI optimizations */
+#undef PNG_MIPS_MMI_OPT
+
+/* Turn on MIPS MSA optimizations at run-time */
+#undef PNG_MIPS_MSA_API_SUPPORTED
+
+/* Check for MIPS MSA support at run-time */
+#undef PNG_MIPS_MSA_CHECK_SUPPORTED
+
+/* Enable MIPS MSA optimizations */
+#undef PNG_MIPS_MSA_OPT
+
+/* Turn on POWERPC VSX optimizations at run-time */
+#undef PNG_POWERPC_VSX_API_SUPPORTED
+
+/* Check for POWERPC VSX support at run-time */
+#undef PNG_POWERPC_VSX_CHECK_SUPPORTED
+
+/* Enable POWERPC VSX optimizations */
+#undef PNG_POWERPC_VSX_OPT
+
+/* Define to 1 if all of the C89 standard headers exist (not just the ones
+   required in a freestanding environment). This macro is provided for
+   backward compatibility; new code need not use it. */
+#undef STDC_HEADERS
+
+/* Define to 1 if your <sys/time.h> declares 'struct tm'. */
+#undef TM_IN_SYS_TIME
+
+/* Version number of package */
+#undef VERSION
+
+/* Define to the equivalent of the C99 'restrict' keyword, or to
+   nothing if this is not supported.  Do not define if restrict is
+   supported only directly.  */
+#undef restrict
+/* Work around a bug in older versions of Sun C++, which did not
+   #define __restrict__ or support _Restrict or __restrict__
+   even though the corresponding Sun C compiler ended up with
+   "#define restrict _Restrict" or "#define restrict __restrict__"
+   in the previous line.  This workaround can be removed once
+   we assume Oracle Developer Studio 12.5 (2016) or later.  */
+#if defined __SUNPRO_CC && !defined __RESTRICT && !defined __restrict__
+# define _Restrict
+# define __restrict__
+#endif
Index: /trunk/src/libs/libpng-1.6.45/config.sub
===================================================================
--- /trunk/src/libs/libpng-1.6.45/config.sub	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/config.sub	(revision 107811)
@@ -0,0 +1,1960 @@
+#! /bin/sh
+# Configuration validation subroutine script.
+#   Copyright 1992-2023 Free Software Foundation, Inc.
+
+# shellcheck disable=SC2006,SC2268 # see below for rationale
+
+timestamp='2023-09-19'
+
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, see <https://www.gnu.org/licenses/>.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that
+# program.  This Exception is an additional permission under section 7
+# of the GNU General Public License, version 3 ("GPLv3").
+
+
+# Please send patches to <config-patches@gnu.org>.
+#
+# Configuration subroutine to validate and canonicalize a configuration type.
+# Supply the specified configuration type as an argument.
+# If it is invalid, we print an error message on stderr and exit with code 1.
+# Otherwise, we print the canonical config type on stdout and succeed.
+
+# You can get the latest version of this script from:
+# https://git.savannah.gnu.org/cgit/config.git/plain/config.sub
+
+# This file is supposed to be the same for all GNU packages
+# and recognize all the CPU types, system types and aliases
+# that are meaningful with *any* GNU software.
+# Each package is responsible for reporting which valid configurations
+# it does not support.  The user should be able to distinguish
+# a failure to support a valid configuration from a meaningless
+# configuration.
+
+# The goal of this file is to map all the various variations of a given
+# machine specification into a single specification in the form:
+#	CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM
+# or in some cases, the newer four-part form:
+#	CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM
+# It is wrong to echo any other type of specification.
+
+# The "shellcheck disable" line above the timestamp inhibits complaints
+# about features and limitations of the classic Bourne shell that were
+# superseded or lifted in POSIX.  However, this script identifies a wide
+# variety of pre-POSIX systems that do not have POSIX shells at all, and
+# even some reasonably current systems (Solaris 10 as case-in-point) still
+# have a pre-POSIX /bin/sh.
+
+me=`echo "$0" | sed -e 's,.*/,,'`
+
+usage="\
+Usage: $0 [OPTION] CPU-MFR-OPSYS or ALIAS
+
+Canonicalize a configuration name.
+
+Options:
+  -h, --help         print this help, then exit
+  -t, --time-stamp   print date of last modification, then exit
+  -v, --version      print version number, then exit
+
+Report bugs and patches to <config-patches@gnu.org>."
+
+version="\
+GNU config.sub ($timestamp)
+
+Copyright 1992-2023 Free Software Foundation, Inc.
+
+This is free software; see the source for copying conditions.  There is NO
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
+
+help="
+Try '$me --help' for more information."
+
+# Parse command line
+while test $# -gt 0 ; do
+  case $1 in
+    --time-stamp | --time* | -t )
+       echo "$timestamp" ; exit ;;
+    --version | -v )
+       echo "$version" ; exit ;;
+    --help | --h* | -h )
+       echo "$usage"; exit ;;
+    -- )     # Stop option processing
+       shift; break ;;
+    - )	# Use stdin as input.
+       break ;;
+    -* )
+       echo "$me: invalid option $1$help" >&2
+       exit 1 ;;
+
+    *local*)
+       # First pass through any local machine types.
+       echo "$1"
+       exit ;;
+
+    * )
+       break ;;
+  esac
+done
+
+case $# in
+ 0) echo "$me: missing argument$help" >&2
+    exit 1;;
+ 1) ;;
+ *) echo "$me: too many arguments$help" >&2
+    exit 1;;
+esac
+
+# Split fields of configuration type
+# shellcheck disable=SC2162
+saved_IFS=$IFS
+IFS="-" read field1 field2 field3 field4 <<EOF
+$1
+EOF
+IFS=$saved_IFS
+
+# Separate into logical components for further validation
+case $1 in
+	*-*-*-*-*)
+		echo "Invalid configuration '$1': more than four components" >&2
+		exit 1
+		;;
+	*-*-*-*)
+		basic_machine=$field1-$field2
+		basic_os=$field3-$field4
+		;;
+	*-*-*)
+		# Ambiguous whether COMPANY is present, or skipped and KERNEL-OS is two
+		# parts
+		maybe_os=$field2-$field3
+		case $maybe_os in
+			nto-qnx* | linux-* | uclinux-uclibc* \
+			| uclinux-gnu* | kfreebsd*-gnu* | knetbsd*-gnu* | netbsd*-gnu* \
+			| netbsd*-eabi* | kopensolaris*-gnu* | cloudabi*-eabi* \
+			| storm-chaos* | os2-emx* | rtmk-nova* | managarm-* \
+			| windows-* )
+				basic_machine=$field1
+				basic_os=$maybe_os
+				;;
+			android-linux)
+				basic_machine=$field1-unknown
+				basic_os=linux-android
+				;;
+			*)
+				basic_machine=$field1-$field2
+				basic_os=$field3
+				;;
+		esac
+		;;
+	*-*)
+		# A lone config we happen to match not fitting any pattern
+		case $field1-$field2 in
+			decstation-3100)
+				basic_machine=mips-dec
+				basic_os=
+				;;
+			*-*)
+				# Second component is usually, but not always the OS
+				case $field2 in
+					# Prevent following clause from handling this valid os
+					sun*os*)
+						basic_machine=$field1
+						basic_os=$field2
+						;;
+					zephyr*)
+						basic_machine=$field1-unknown
+						basic_os=$field2
+						;;
+					# Manufacturers
+					dec* | mips* | sequent* | encore* | pc533* | sgi* | sony* \
+					| att* | 7300* | 3300* | delta* | motorola* | sun[234]* \
+					| unicom* | ibm* | next | hp | isi* | apollo | altos* \
+					| convergent* | ncr* | news | 32* | 3600* | 3100* \
+					| hitachi* | c[123]* | convex* | sun | crds | omron* | dg \
+					| ultra | tti* | harris | dolphin | highlevel | gould \
+					| cbm | ns | masscomp | apple | axis | knuth | cray \
+					| microblaze* | sim | cisco \
+					| oki | wec | wrs | winbond)
+						basic_machine=$field1-$field2
+						basic_os=
+						;;
+					*)
+						basic_machine=$field1
+						basic_os=$field2
+						;;
+				esac
+			;;
+		esac
+		;;
+	*)
+		# Convert single-component short-hands not valid as part of
+		# multi-component configurations.
+		case $field1 in
+			386bsd)
+				basic_machine=i386-pc
+				basic_os=bsd
+				;;
+			a29khif)
+				basic_machine=a29k-amd
+				basic_os=udi
+				;;
+			adobe68k)
+				basic_machine=m68010-adobe
+				basic_os=scout
+				;;
+			alliant)
+				basic_machine=fx80-alliant
+				basic_os=
+				;;
+			altos | altos3068)
+				basic_machine=m68k-altos
+				basic_os=
+				;;
+			am29k)
+				basic_machine=a29k-none
+				basic_os=bsd
+				;;
+			amdahl)
+				basic_machine=580-amdahl
+				basic_os=sysv
+				;;
+			amiga)
+				basic_machine=m68k-unknown
+				basic_os=
+				;;
+			amigaos | amigados)
+				basic_machine=m68k-unknown
+				basic_os=amigaos
+				;;
+			amigaunix | amix)
+				basic_machine=m68k-unknown
+				basic_os=sysv4
+				;;
+			apollo68)
+				basic_machine=m68k-apollo
+				basic_os=sysv
+				;;
+			apollo68bsd)
+				basic_machine=m68k-apollo
+				basic_os=bsd
+				;;
+			aros)
+				basic_machine=i386-pc
+				basic_os=aros
+				;;
+			aux)
+				basic_machine=m68k-apple
+				basic_os=aux
+				;;
+			balance)
+				basic_machine=ns32k-sequent
+				basic_os=dynix
+				;;
+			blackfin)
+				basic_machine=bfin-unknown
+				basic_os=linux
+				;;
+			cegcc)
+				basic_machine=arm-unknown
+				basic_os=cegcc
+				;;
+			convex-c1)
+				basic_machine=c1-convex
+				basic_os=bsd
+				;;
+			convex-c2)
+				basic_machine=c2-convex
+				basic_os=bsd
+				;;
+			convex-c32)
+				basic_machine=c32-convex
+				basic_os=bsd
+				;;
+			convex-c34)
+				basic_machine=c34-convex
+				basic_os=bsd
+				;;
+			convex-c38)
+				basic_machine=c38-convex
+				basic_os=bsd
+				;;
+			cray)
+				basic_machine=j90-cray
+				basic_os=unicos
+				;;
+			crds | unos)
+				basic_machine=m68k-crds
+				basic_os=
+				;;
+			da30)
+				basic_machine=m68k-da30
+				basic_os=
+				;;
+			decstation | pmax | pmin | dec3100 | decstatn)
+				basic_machine=mips-dec
+				basic_os=
+				;;
+			delta88)
+				basic_machine=m88k-motorola
+				basic_os=sysv3
+				;;
+			dicos)
+				basic_machine=i686-pc
+				basic_os=dicos
+				;;
+			djgpp)
+				basic_machine=i586-pc
+				basic_os=msdosdjgpp
+				;;
+			ebmon29k)
+				basic_machine=a29k-amd
+				basic_os=ebmon
+				;;
+			es1800 | OSE68k | ose68k | ose | OSE)
+				basic_machine=m68k-ericsson
+				basic_os=ose
+				;;
+			gmicro)
+				basic_machine=tron-gmicro
+				basic_os=sysv
+				;;
+			go32)
+				basic_machine=i386-pc
+				basic_os=go32
+				;;
+			h8300hms)
+				basic_machine=h8300-hitachi
+				basic_os=hms
+				;;
+			h8300xray)
+				basic_machine=h8300-hitachi
+				basic_os=xray
+				;;
+			h8500hms)
+				basic_machine=h8500-hitachi
+				basic_os=hms
+				;;
+			harris)
+				basic_machine=m88k-harris
+				basic_os=sysv3
+				;;
+			hp300 | hp300hpux)
+				basic_machine=m68k-hp
+				basic_os=hpux
+				;;
+			hp300bsd)
+				basic_machine=m68k-hp
+				basic_os=bsd
+				;;
+			hppaosf)
+				basic_machine=hppa1.1-hp
+				basic_os=osf
+				;;
+			hppro)
+				basic_machine=hppa1.1-hp
+				basic_os=proelf
+				;;
+			i386mach)
+				basic_machine=i386-mach
+				basic_os=mach
+				;;
+			isi68 | isi)
+				basic_machine=m68k-isi
+				basic_os=sysv
+				;;
+			m68knommu)
+				basic_machine=m68k-unknown
+				basic_os=linux
+				;;
+			magnum | m3230)
+				basic_machine=mips-mips
+				basic_os=sysv
+				;;
+			merlin)
+				basic_machine=ns32k-utek
+				basic_os=sysv
+				;;
+			mingw64)
+				basic_machine=x86_64-pc
+				basic_os=mingw64
+				;;
+			mingw32)
+				basic_machine=i686-pc
+				basic_os=mingw32
+				;;
+			mingw32ce)
+				basic_machine=arm-unknown
+				basic_os=mingw32ce
+				;;
+			monitor)
+				basic_machine=m68k-rom68k
+				basic_os=coff
+				;;
+			morphos)
+				basic_machine=powerpc-unknown
+				basic_os=morphos
+				;;
+			moxiebox)
+				basic_machine=moxie-unknown
+				basic_os=moxiebox
+				;;
+			msdos)
+				basic_machine=i386-pc
+				basic_os=msdos
+				;;
+			msys)
+				basic_machine=i686-pc
+				basic_os=msys
+				;;
+			mvs)
+				basic_machine=i370-ibm
+				basic_os=mvs
+				;;
+			nacl)
+				basic_machine=le32-unknown
+				basic_os=nacl
+				;;
+			ncr3000)
+				basic_machine=i486-ncr
+				basic_os=sysv4
+				;;
+			netbsd386)
+				basic_machine=i386-pc
+				basic_os=netbsd
+				;;
+			netwinder)
+				basic_machine=armv4l-rebel
+				basic_os=linux
+				;;
+			news | news700 | news800 | news900)
+				basic_machine=m68k-sony
+				basic_os=newsos
+				;;
+			news1000)
+				basic_machine=m68030-sony
+				basic_os=newsos
+				;;
+			necv70)
+				basic_machine=v70-nec
+				basic_os=sysv
+				;;
+			nh3000)
+				basic_machine=m68k-harris
+				basic_os=cxux
+				;;
+			nh[45]000)
+				basic_machine=m88k-harris
+				basic_os=cxux
+				;;
+			nindy960)
+				basic_machine=i960-intel
+				basic_os=nindy
+				;;
+			mon960)
+				basic_machine=i960-intel
+				basic_os=mon960
+				;;
+			nonstopux)
+				basic_machine=mips-compaq
+				basic_os=nonstopux
+				;;
+			os400)
+				basic_machine=powerpc-ibm
+				basic_os=os400
+				;;
+			OSE68000 | ose68000)
+				basic_machine=m68000-ericsson
+				basic_os=ose
+				;;
+			os68k)
+				basic_machine=m68k-none
+				basic_os=os68k
+				;;
+			paragon)
+				basic_machine=i860-intel
+				basic_os=osf
+				;;
+			parisc)
+				basic_machine=hppa-unknown
+				basic_os=linux
+				;;
+			psp)
+				basic_machine=mipsallegrexel-sony
+				basic_os=psp
+				;;
+			pw32)
+				basic_machine=i586-unknown
+				basic_os=pw32
+				;;
+			rdos | rdos64)
+				basic_machine=x86_64-pc
+				basic_os=rdos
+				;;
+			rdos32)
+				basic_machine=i386-pc
+				basic_os=rdos
+				;;
+			rom68k)
+				basic_machine=m68k-rom68k
+				basic_os=coff
+				;;
+			sa29200)
+				basic_machine=a29k-amd
+				basic_os=udi
+				;;
+			sei)
+				basic_machine=mips-sei
+				basic_os=seiux
+				;;
+			sequent)
+				basic_machine=i386-sequent
+				basic_os=
+				;;
+			sps7)
+				basic_machine=m68k-bull
+				basic_os=sysv2
+				;;
+			st2000)
+				basic_machine=m68k-tandem
+				basic_os=
+				;;
+			stratus)
+				basic_machine=i860-stratus
+				basic_os=sysv4
+				;;
+			sun2)
+				basic_machine=m68000-sun
+				basic_os=
+				;;
+			sun2os3)
+				basic_machine=m68000-sun
+				basic_os=sunos3
+				;;
+			sun2os4)
+				basic_machine=m68000-sun
+				basic_os=sunos4
+				;;
+			sun3)
+				basic_machine=m68k-sun
+				basic_os=
+				;;
+			sun3os3)
+				basic_machine=m68k-sun
+				basic_os=sunos3
+				;;
+			sun3os4)
+				basic_machine=m68k-sun
+				basic_os=sunos4
+				;;
+			sun4)
+				basic_machine=sparc-sun
+				basic_os=
+				;;
+			sun4os3)
+				basic_machine=sparc-sun
+				basic_os=sunos3
+				;;
+			sun4os4)
+				basic_machine=sparc-sun
+				basic_os=sunos4
+				;;
+			sun4sol2)
+				basic_machine=sparc-sun
+				basic_os=solaris2
+				;;
+			sun386 | sun386i | roadrunner)
+				basic_machine=i386-sun
+				basic_os=
+				;;
+			sv1)
+				basic_machine=sv1-cray
+				basic_os=unicos
+				;;
+			symmetry)
+				basic_machine=i386-sequent
+				basic_os=dynix
+				;;
+			t3e)
+				basic_machine=alphaev5-cray
+				basic_os=unicos
+				;;
+			t90)
+				basic_machine=t90-cray
+				basic_os=unicos
+				;;
+			toad1)
+				basic_machine=pdp10-xkl
+				basic_os=tops20
+				;;
+			tpf)
+				basic_machine=s390x-ibm
+				basic_os=tpf
+				;;
+			udi29k)
+				basic_machine=a29k-amd
+				basic_os=udi
+				;;
+			ultra3)
+				basic_machine=a29k-nyu
+				basic_os=sym1
+				;;
+			v810 | necv810)
+				basic_machine=v810-nec
+				basic_os=none
+				;;
+			vaxv)
+				basic_machine=vax-dec
+				basic_os=sysv
+				;;
+			vms)
+				basic_machine=vax-dec
+				basic_os=vms
+				;;
+			vsta)
+				basic_machine=i386-pc
+				basic_os=vsta
+				;;
+			vxworks960)
+				basic_machine=i960-wrs
+				basic_os=vxworks
+				;;
+			vxworks68)
+				basic_machine=m68k-wrs
+				basic_os=vxworks
+				;;
+			vxworks29k)
+				basic_machine=a29k-wrs
+				basic_os=vxworks
+				;;
+			xbox)
+				basic_machine=i686-pc
+				basic_os=mingw32
+				;;
+			ymp)
+				basic_machine=ymp-cray
+				basic_os=unicos
+				;;
+			*)
+				basic_machine=$1
+				basic_os=
+				;;
+		esac
+		;;
+esac
+
+# Decode 1-component or ad-hoc basic machines
+case $basic_machine in
+	# Here we handle the default manufacturer of certain CPU types.  It is in
+	# some cases the only manufacturer, in others, it is the most popular.
+	w89k)
+		cpu=hppa1.1
+		vendor=winbond
+		;;
+	op50n)
+		cpu=hppa1.1
+		vendor=oki
+		;;
+	op60c)
+		cpu=hppa1.1
+		vendor=oki
+		;;
+	ibm*)
+		cpu=i370
+		vendor=ibm
+		;;
+	orion105)
+		cpu=clipper
+		vendor=highlevel
+		;;
+	mac | mpw | mac-mpw)
+		cpu=m68k
+		vendor=apple
+		;;
+	pmac | pmac-mpw)
+		cpu=powerpc
+		vendor=apple
+		;;
+
+	# Recognize the various machine names and aliases which stand
+	# for a CPU type and a company and sometimes even an OS.
+	3b1 | 7300 | 7300-att | att-7300 | pc7300 | safari | unixpc)
+		cpu=m68000
+		vendor=att
+		;;
+	3b*)
+		cpu=we32k
+		vendor=att
+		;;
+	bluegene*)
+		cpu=powerpc
+		vendor=ibm
+		basic_os=cnk
+		;;
+	decsystem10* | dec10*)
+		cpu=pdp10
+		vendor=dec
+		basic_os=tops10
+		;;
+	decsystem20* | dec20*)
+		cpu=pdp10
+		vendor=dec
+		basic_os=tops20
+		;;
+	delta | 3300 | motorola-3300 | motorola-delta \
+	      | 3300-motorola | delta-motorola)
+		cpu=m68k
+		vendor=motorola
+		;;
+	dpx2*)
+		cpu=m68k
+		vendor=bull
+		basic_os=sysv3
+		;;
+	encore | umax | mmax)
+		cpu=ns32k
+		vendor=encore
+		;;
+	elxsi)
+		cpu=elxsi
+		vendor=elxsi
+		basic_os=${basic_os:-bsd}
+		;;
+	fx2800)
+		cpu=i860
+		vendor=alliant
+		;;
+	genix)
+		cpu=ns32k
+		vendor=ns
+		;;
+	h3050r* | hiux*)
+		cpu=hppa1.1
+		vendor=hitachi
+		basic_os=hiuxwe2
+		;;
+	hp3k9[0-9][0-9] | hp9[0-9][0-9])
+		cpu=hppa1.0
+		vendor=hp
+		;;
+	hp9k2[0-9][0-9] | hp9k31[0-9])
+		cpu=m68000
+		vendor=hp
+		;;
+	hp9k3[2-9][0-9])
+		cpu=m68k
+		vendor=hp
+		;;
+	hp9k6[0-9][0-9] | hp6[0-9][0-9])
+		cpu=hppa1.0
+		vendor=hp
+		;;
+	hp9k7[0-79][0-9] | hp7[0-79][0-9])
+		cpu=hppa1.1
+		vendor=hp
+		;;
+	hp9k78[0-9] | hp78[0-9])
+		# FIXME: really hppa2.0-hp
+		cpu=hppa1.1
+		vendor=hp
+		;;
+	hp9k8[67]1 | hp8[67]1 | hp9k80[24] | hp80[24] | hp9k8[78]9 | hp8[78]9 | hp9k893 | hp893)
+		# FIXME: really hppa2.0-hp
+		cpu=hppa1.1
+		vendor=hp
+		;;
+	hp9k8[0-9][13679] | hp8[0-9][13679])
+		cpu=hppa1.1
+		vendor=hp
+		;;
+	hp9k8[0-9][0-9] | hp8[0-9][0-9])
+		cpu=hppa1.0
+		vendor=hp
+		;;
+	i*86v32)
+		cpu=`echo "$1" | sed -e 's/86.*/86/'`
+		vendor=pc
+		basic_os=sysv32
+		;;
+	i*86v4*)
+		cpu=`echo "$1" | sed -e 's/86.*/86/'`
+		vendor=pc
+		basic_os=sysv4
+		;;
+	i*86v)
+		cpu=`echo "$1" | sed -e 's/86.*/86/'`
+		vendor=pc
+		basic_os=sysv
+		;;
+	i*86sol2)
+		cpu=`echo "$1" | sed -e 's/86.*/86/'`
+		vendor=pc
+		basic_os=solaris2
+		;;
+	j90 | j90-cray)
+		cpu=j90
+		vendor=cray
+		basic_os=${basic_os:-unicos}
+		;;
+	iris | iris4d)
+		cpu=mips
+		vendor=sgi
+		case $basic_os in
+		    irix*)
+			;;
+		    *)
+			basic_os=irix4
+			;;
+		esac
+		;;
+	miniframe)
+		cpu=m68000
+		vendor=convergent
+		;;
+	*mint | mint[0-9]* | *MiNT | *MiNT[0-9]*)
+		cpu=m68k
+		vendor=atari
+		basic_os=mint
+		;;
+	news-3600 | risc-news)
+		cpu=mips
+		vendor=sony
+		basic_os=newsos
+		;;
+	next | m*-next)
+		cpu=m68k
+		vendor=next
+		case $basic_os in
+		    openstep*)
+		        ;;
+		    nextstep*)
+			;;
+		    ns2*)
+		      basic_os=nextstep2
+			;;
+		    *)
+		      basic_os=nextstep3
+			;;
+		esac
+		;;
+	np1)
+		cpu=np1
+		vendor=gould
+		;;
+	op50n-* | op60c-*)
+		cpu=hppa1.1
+		vendor=oki
+		basic_os=proelf
+		;;
+	pa-hitachi)
+		cpu=hppa1.1
+		vendor=hitachi
+		basic_os=hiuxwe2
+		;;
+	pbd)
+		cpu=sparc
+		vendor=tti
+		;;
+	pbb)
+		cpu=m68k
+		vendor=tti
+		;;
+	pc532)
+		cpu=ns32k
+		vendor=pc532
+		;;
+	pn)
+		cpu=pn
+		vendor=gould
+		;;
+	power)
+		cpu=power
+		vendor=ibm
+		;;
+	ps2)
+		cpu=i386
+		vendor=ibm
+		;;
+	rm[46]00)
+		cpu=mips
+		vendor=siemens
+		;;
+	rtpc | rtpc-*)
+		cpu=romp
+		vendor=ibm
+		;;
+	sde)
+		cpu=mipsisa32
+		vendor=sde
+		basic_os=${basic_os:-elf}
+		;;
+	simso-wrs)
+		cpu=sparclite
+		vendor=wrs
+		basic_os=vxworks
+		;;
+	tower | tower-32)
+		cpu=m68k
+		vendor=ncr
+		;;
+	vpp*|vx|vx-*)
+		cpu=f301
+		vendor=fujitsu
+		;;
+	w65)
+		cpu=w65
+		vendor=wdc
+		;;
+	w89k-*)
+		cpu=hppa1.1
+		vendor=winbond
+		basic_os=proelf
+		;;
+	none)
+		cpu=none
+		vendor=none
+		;;
+	leon|leon[3-9])
+		cpu=sparc
+		vendor=$basic_machine
+		;;
+	leon-*|leon[3-9]-*)
+		cpu=sparc
+		vendor=`echo "$basic_machine" | sed 's/-.*//'`
+		;;
+
+	*-*)
+		# shellcheck disable=SC2162
+		saved_IFS=$IFS
+		IFS="-" read cpu vendor <<EOF
+$basic_machine
+EOF
+		IFS=$saved_IFS
+		;;
+	# We use 'pc' rather than 'unknown'
+	# because (1) that's what they normally are, and
+	# (2) the word "unknown" tends to confuse beginning users.
+	i*86 | x86_64)
+		cpu=$basic_machine
+		vendor=pc
+		;;
+	# These rules are duplicated from below for sake of the special case above;
+	# i.e. things that normalized to x86 arches should also default to "pc"
+	pc98)
+		cpu=i386
+		vendor=pc
+		;;
+	x64 | amd64)
+		cpu=x86_64
+		vendor=pc
+		;;
+	# Recognize the basic CPU types without company name.
+	*)
+		cpu=$basic_machine
+		vendor=unknown
+		;;
+esac
+
+unset -v basic_machine
+
+# Decode basic machines in the full and proper CPU-Company form.
+case $cpu-$vendor in
+	# Here we handle the default manufacturer of certain CPU types in canonical form. It is in
+	# some cases the only manufacturer, in others, it is the most popular.
+	craynv-unknown)
+		vendor=cray
+		basic_os=${basic_os:-unicosmp}
+		;;
+	c90-unknown | c90-cray)
+		vendor=cray
+		basic_os=${Basic_os:-unicos}
+		;;
+	fx80-unknown)
+		vendor=alliant
+		;;
+	romp-unknown)
+		vendor=ibm
+		;;
+	mmix-unknown)
+		vendor=knuth
+		;;
+	microblaze-unknown | microblazeel-unknown)
+		vendor=xilinx
+		;;
+	rs6000-unknown)
+		vendor=ibm
+		;;
+	vax-unknown)
+		vendor=dec
+		;;
+	pdp11-unknown)
+		vendor=dec
+		;;
+	we32k-unknown)
+		vendor=att
+		;;
+	cydra-unknown)
+		vendor=cydrome
+		;;
+	i370-ibm*)
+		vendor=ibm
+		;;
+	orion-unknown)
+		vendor=highlevel
+		;;
+	xps-unknown | xps100-unknown)
+		cpu=xps100
+		vendor=honeywell
+		;;
+
+	# Here we normalize CPU types with a missing or matching vendor
+	armh-unknown | armh-alt)
+		cpu=armv7l
+		vendor=alt
+		basic_os=${basic_os:-linux-gnueabihf}
+		;;
+	dpx20-unknown | dpx20-bull)
+		cpu=rs6000
+		vendor=bull
+		basic_os=${basic_os:-bosx}
+		;;
+
+	# Here we normalize CPU types irrespective of the vendor
+	amd64-*)
+		cpu=x86_64
+		;;
+	blackfin-*)
+		cpu=bfin
+		basic_os=linux
+		;;
+	c54x-*)
+		cpu=tic54x
+		;;
+	c55x-*)
+		cpu=tic55x
+		;;
+	c6x-*)
+		cpu=tic6x
+		;;
+	e500v[12]-*)
+		cpu=powerpc
+		basic_os=${basic_os}"spe"
+		;;
+	mips3*-*)
+		cpu=mips64
+		;;
+	ms1-*)
+		cpu=mt
+		;;
+	m68knommu-*)
+		cpu=m68k
+		basic_os=linux
+		;;
+	m9s12z-* | m68hcs12z-* | hcs12z-* | s12z-*)
+		cpu=s12z
+		;;
+	openrisc-*)
+		cpu=or32
+		;;
+	parisc-*)
+		cpu=hppa
+		basic_os=linux
+		;;
+	pentium-* | p5-* | k5-* | k6-* | nexgen-* | viac3-*)
+		cpu=i586
+		;;
+	pentiumpro-* | p6-* | 6x86-* | athlon-* | athlon_*-*)
+		cpu=i686
+		;;
+	pentiumii-* | pentium2-* | pentiumiii-* | pentium3-*)
+		cpu=i686
+		;;
+	pentium4-*)
+		cpu=i786
+		;;
+	pc98-*)
+		cpu=i386
+		;;
+	ppc-* | ppcbe-*)
+		cpu=powerpc
+		;;
+	ppcle-* | powerpclittle-*)
+		cpu=powerpcle
+		;;
+	ppc64-*)
+		cpu=powerpc64
+		;;
+	ppc64le-* | powerpc64little-*)
+		cpu=powerpc64le
+		;;
+	sb1-*)
+		cpu=mipsisa64sb1
+		;;
+	sb1el-*)
+		cpu=mipsisa64sb1el
+		;;
+	sh5e[lb]-*)
+		cpu=`echo "$cpu" | sed 's/^\(sh.\)e\(.\)$/\1\2e/'`
+		;;
+	spur-*)
+		cpu=spur
+		;;
+	strongarm-* | thumb-*)
+		cpu=arm
+		;;
+	tx39-*)
+		cpu=mipstx39
+		;;
+	tx39el-*)
+		cpu=mipstx39el
+		;;
+	x64-*)
+		cpu=x86_64
+		;;
+	xscale-* | xscalee[bl]-*)
+		cpu=`echo "$cpu" | sed 's/^xscale/arm/'`
+		;;
+	arm64-* | aarch64le-*)
+		cpu=aarch64
+		;;
+
+	# Recognize the canonical CPU Types that limit and/or modify the
+	# company names they are paired with.
+	cr16-*)
+		basic_os=${basic_os:-elf}
+		;;
+	crisv32-* | etraxfs*-*)
+		cpu=crisv32
+		vendor=axis
+		;;
+	cris-* | etrax*-*)
+		cpu=cris
+		vendor=axis
+		;;
+	crx-*)
+		basic_os=${basic_os:-elf}
+		;;
+	neo-tandem)
+		cpu=neo
+		vendor=tandem
+		;;
+	nse-tandem)
+		cpu=nse
+		vendor=tandem
+		;;
+	nsr-tandem)
+		cpu=nsr
+		vendor=tandem
+		;;
+	nsv-tandem)
+		cpu=nsv
+		vendor=tandem
+		;;
+	nsx-tandem)
+		cpu=nsx
+		vendor=tandem
+		;;
+	mipsallegrexel-sony)
+		cpu=mipsallegrexel
+		vendor=sony
+		;;
+	tile*-*)
+		basic_os=${basic_os:-linux-gnu}
+		;;
+
+	*)
+		# Recognize the canonical CPU types that are allowed with any
+		# company name.
+		case $cpu in
+			1750a | 580 \
+			| a29k \
+			| aarch64 | aarch64_be | aarch64c | arm64ec \
+			| abacus \
+			| alpha | alphaev[4-8] | alphaev56 | alphaev6[78] \
+			| alpha64 | alpha64ev[4-8] | alpha64ev56 | alpha64ev6[78] \
+			| alphapca5[67] | alpha64pca5[67] \
+			| am33_2.0 \
+			| amdgcn \
+			| arc | arceb | arc32 | arc64 \
+			| arm | arm[lb]e | arme[lb] | armv* \
+			| avr | avr32 \
+			| asmjs \
+			| ba \
+			| be32 | be64 \
+			| bfin | bpf | bs2000 \
+			| c[123]* | c30 | [cjt]90 | c4x \
+			| c8051 | clipper | craynv | csky | cydra \
+			| d10v | d30v | dlx | dsp16xx \
+			| e2k | elxsi | epiphany \
+			| f30[01] | f700 | fido | fr30 | frv | ft32 | fx80 \
+			| javascript \
+			| h8300 | h8500 \
+			| hppa | hppa1.[01] | hppa2.0 | hppa2.0[nw] | hppa64 \
+			| hexagon \
+			| i370 | i*86 | i860 | i960 | ia16 | ia64 \
+			| ip2k | iq2000 \
+			| k1om \
+			| kvx \
+			| le32 | le64 \
+			| lm32 \
+			| loongarch32 | loongarch64 \
+			| m32c | m32r | m32rle \
+			| m5200 | m68000 | m680[012346]0 | m68360 | m683?2 | m68k \
+			| m6811 | m68hc11 | m6812 | m68hc12 | m68hcs12x \
+			| m88110 | m88k | maxq | mb | mcore | mep | metag \
+			| microblaze | microblazeel \
+			| mips* \
+			| mmix \
+			| mn10200 | mn10300 \
+			| moxie \
+			| mt \
+			| msp430 \
+			| nds32 | nds32le | nds32be \
+			| nfp \
+			| nios | nios2 | nios2eb | nios2el \
+			| none | np1 | ns16k | ns32k | nvptx \
+			| open8 \
+			| or1k* \
+			| or32 \
+			| orion \
+			| picochip \
+			| pdp10 | pdp11 | pj | pjl | pn | power \
+			| powerpc | powerpc64 | powerpc64le | powerpcle | powerpcspe \
+			| pru \
+			| pyramid \
+			| riscv | riscv32 | riscv32be | riscv64 | riscv64be \
+			| rl78 | romp | rs6000 | rx \
+			| s390 | s390x \
+			| score \
+			| sh | shl \
+			| sh[1234] | sh[24]a | sh[24]ae[lb] | sh[23]e | she[lb] | sh[lb]e \
+			| sh[1234]e[lb] |  sh[12345][lb]e | sh[23]ele | sh64 | sh64le \
+			| sparc | sparc64 | sparc64b | sparc64v | sparc86x | sparclet \
+			| sparclite \
+			| sparcv8 | sparcv9 | sparcv9b | sparcv9v | sv1 | sx* \
+			| spu \
+			| tahoe \
+			| thumbv7* \
+			| tic30 | tic4x | tic54x | tic55x | tic6x | tic80 \
+			| tron \
+			| ubicom32 \
+			| v70 | v850 | v850e | v850e1 | v850es | v850e2 | v850e2v3 \
+			| vax \
+			| visium \
+			| w65 \
+			| wasm32 | wasm64 \
+			| we32k \
+			| x86 | x86_64 | xc16x | xgate | xps100 \
+			| xstormy16 | xtensa* \
+			| ymp \
+			| z8k | z80)
+				;;
+
+			*)
+				echo "Invalid configuration '$1': machine '$cpu-$vendor' not recognized" 1>&2
+				exit 1
+				;;
+		esac
+		;;
+esac
+
+# Here we canonicalize certain aliases for manufacturers.
+case $vendor in
+	digital*)
+		vendor=dec
+		;;
+	commodore*)
+		vendor=cbm
+		;;
+	*)
+		;;
+esac
+
+# Decode manufacturer-specific aliases for certain operating systems.
+
+if test x"$basic_os" != x
+then
+
+# First recognize some ad-hoc cases, or perhaps split kernel-os, or else just
+# set os.
+obj=
+case $basic_os in
+	gnu/linux*)
+		kernel=linux
+		os=`echo "$basic_os" | sed -e 's|gnu/linux|gnu|'`
+		;;
+	os2-emx)
+		kernel=os2
+		os=`echo "$basic_os" | sed -e 's|os2-emx|emx|'`
+		;;
+	nto-qnx*)
+		kernel=nto
+		os=`echo "$basic_os" | sed -e 's|nto-qnx|qnx|'`
+		;;
+	*-*)
+		# shellcheck disable=SC2162
+		saved_IFS=$IFS
+		IFS="-" read kernel os <<EOF
+$basic_os
+EOF
+		IFS=$saved_IFS
+		;;
+	# Default OS when just kernel was specified
+	nto*)
+		kernel=nto
+		os=`echo "$basic_os" | sed -e 's|nto|qnx|'`
+		;;
+	linux*)
+		kernel=linux
+		os=`echo "$basic_os" | sed -e 's|linux|gnu|'`
+		;;
+	managarm*)
+		kernel=managarm
+		os=`echo "$basic_os" | sed -e 's|managarm|mlibc|'`
+		;;
+	*)
+		kernel=
+		os=$basic_os
+		;;
+esac
+
+# Now, normalize the OS (knowing we just have one component, it's not a kernel,
+# etc.)
+case $os in
+	# First match some system type aliases that might get confused
+	# with valid system types.
+	# solaris* is a basic system type, with this one exception.
+	auroraux)
+		os=auroraux
+		;;
+	bluegene*)
+		os=cnk
+		;;
+	solaris1 | solaris1.*)
+		os=`echo "$os" | sed -e 's|solaris1|sunos4|'`
+		;;
+	solaris)
+		os=solaris2
+		;;
+	unixware*)
+		os=sysv4.2uw
+		;;
+	# es1800 is here to avoid being matched by es* (a different OS)
+	es1800*)
+		os=ose
+		;;
+	# Some version numbers need modification
+	chorusos*)
+		os=chorusos
+		;;
+	isc)
+		os=isc2.2
+		;;
+	sco6)
+		os=sco5v6
+		;;
+	sco5)
+		os=sco3.2v5
+		;;
+	sco4)
+		os=sco3.2v4
+		;;
+	sco3.2.[4-9]*)
+		os=`echo "$os" | sed -e 's/sco3.2./sco3.2v/'`
+		;;
+	sco*v* | scout)
+		# Don't match below
+		;;
+	sco*)
+		os=sco3.2v2
+		;;
+	psos*)
+		os=psos
+		;;
+	qnx*)
+		os=qnx
+		;;
+	hiux*)
+		os=hiuxwe2
+		;;
+	lynx*178)
+		os=lynxos178
+		;;
+	lynx*5)
+		os=lynxos5
+		;;
+	lynxos*)
+		# don't get caught up in next wildcard
+		;;
+	lynx*)
+		os=lynxos
+		;;
+	mac[0-9]*)
+		os=`echo "$os" | sed -e 's|mac|macos|'`
+		;;
+	opened*)
+		os=openedition
+		;;
+	os400*)
+		os=os400
+		;;
+	sunos5*)
+		os=`echo "$os" | sed -e 's|sunos5|solaris2|'`
+		;;
+	sunos6*)
+		os=`echo "$os" | sed -e 's|sunos6|solaris3|'`
+		;;
+	wince*)
+		os=wince
+		;;
+	utek*)
+		os=bsd
+		;;
+	dynix*)
+		os=bsd
+		;;
+	acis*)
+		os=aos
+		;;
+	atheos*)
+		os=atheos
+		;;
+	syllable*)
+		os=syllable
+		;;
+	386bsd)
+		os=bsd
+		;;
+	ctix* | uts*)
+		os=sysv
+		;;
+	nova*)
+		os=rtmk-nova
+		;;
+	ns2)
+		os=nextstep2
+		;;
+	# Preserve the version number of sinix5.
+	sinix5.*)
+		os=`echo "$os" | sed -e 's|sinix|sysv|'`
+		;;
+	sinix*)
+		os=sysv4
+		;;
+	tpf*)
+		os=tpf
+		;;
+	triton*)
+		os=sysv3
+		;;
+	oss*)
+		os=sysv3
+		;;
+	svr4*)
+		os=sysv4
+		;;
+	svr3)
+		os=sysv3
+		;;
+	sysvr4)
+		os=sysv4
+		;;
+	ose*)
+		os=ose
+		;;
+	*mint | mint[0-9]* | *MiNT | MiNT[0-9]*)
+		os=mint
+		;;
+	dicos*)
+		os=dicos
+		;;
+	pikeos*)
+		# Until real need of OS specific support for
+		# particular features comes up, bare metal
+		# configurations are quite functional.
+		case $cpu in
+		    arm*)
+			os=eabi
+			;;
+		    *)
+			os=
+			obj=elf
+			;;
+		esac
+		;;
+	aout* | coff* | elf* | pe*)
+		# These are machine code file formats, not OSes
+		obj=$os
+		os=
+		;;
+	*)
+		# No normalization, but not necessarily accepted, that comes below.
+		;;
+esac
+
+else
+
+# Here we handle the default operating systems that come with various machines.
+# The value should be what the vendor currently ships out the door with their
+# machine or put another way, the most popular os provided with the machine.
+
+# Note that if you're going to try to match "-MANUFACTURER" here (say,
+# "-sun"), then you have to tell the case statement up towards the top
+# that MANUFACTURER isn't an operating system.  Otherwise, code above
+# will signal an error saying that MANUFACTURER isn't an operating
+# system, and we'll never get to this point.
+
+kernel=
+obj=
+case $cpu-$vendor in
+	score-*)
+		os=
+		obj=elf
+		;;
+	spu-*)
+		os=
+		obj=elf
+		;;
+	*-acorn)
+		os=riscix1.2
+		;;
+	arm*-rebel)
+		kernel=linux
+		os=gnu
+		;;
+	arm*-semi)
+		os=
+		obj=aout
+		;;
+	c4x-* | tic4x-*)
+		os=
+		obj=coff
+		;;
+	c8051-*)
+		os=
+		obj=elf
+		;;
+	clipper-intergraph)
+		os=clix
+		;;
+	hexagon-*)
+		os=
+		obj=elf
+		;;
+	tic54x-*)
+		os=
+		obj=coff
+		;;
+	tic55x-*)
+		os=
+		obj=coff
+		;;
+	tic6x-*)
+		os=
+		obj=coff
+		;;
+	# This must come before the *-dec entry.
+	pdp10-*)
+		os=tops20
+		;;
+	pdp11-*)
+		os=none
+		;;
+	*-dec | vax-*)
+		os=ultrix4.2
+		;;
+	m68*-apollo)
+		os=domain
+		;;
+	i386-sun)
+		os=sunos4.0.2
+		;;
+	m68000-sun)
+		os=sunos3
+		;;
+	m68*-cisco)
+		os=
+		obj=aout
+		;;
+	mep-*)
+		os=
+		obj=elf
+		;;
+	mips*-cisco)
+		os=
+		obj=elf
+		;;
+	mips*-*)
+		os=
+		obj=elf
+		;;
+	or32-*)
+		os=
+		obj=coff
+		;;
+	*-tti)	# must be before sparc entry or we get the wrong os.
+		os=sysv3
+		;;
+	sparc-* | *-sun)
+		os=sunos4.1.1
+		;;
+	pru-*)
+		os=
+		obj=elf
+		;;
+	*-be)
+		os=beos
+		;;
+	*-ibm)
+		os=aix
+		;;
+	*-knuth)
+		os=mmixware
+		;;
+	*-wec)
+		os=proelf
+		;;
+	*-winbond)
+		os=proelf
+		;;
+	*-oki)
+		os=proelf
+		;;
+	*-hp)
+		os=hpux
+		;;
+	*-hitachi)
+		os=hiux
+		;;
+	i860-* | *-att | *-ncr | *-altos | *-motorola | *-convergent)
+		os=sysv
+		;;
+	*-cbm)
+		os=amigaos
+		;;
+	*-dg)
+		os=dgux
+		;;
+	*-dolphin)
+		os=sysv3
+		;;
+	m68k-ccur)
+		os=rtu
+		;;
+	m88k-omron*)
+		os=luna
+		;;
+	*-next)
+		os=nextstep
+		;;
+	*-sequent)
+		os=ptx
+		;;
+	*-crds)
+		os=unos
+		;;
+	*-ns)
+		os=genix
+		;;
+	i370-*)
+		os=mvs
+		;;
+	*-gould)
+		os=sysv
+		;;
+	*-highlevel)
+		os=bsd
+		;;
+	*-encore)
+		os=bsd
+		;;
+	*-sgi)
+		os=irix
+		;;
+	*-siemens)
+		os=sysv4
+		;;
+	*-masscomp)
+		os=rtu
+		;;
+	f30[01]-fujitsu | f700-fujitsu)
+		os=uxpv
+		;;
+	*-rom68k)
+		os=
+		obj=coff
+		;;
+	*-*bug)
+		os=
+		obj=coff
+		;;
+	*-apple)
+		os=macos
+		;;
+	*-atari*)
+		os=mint
+		;;
+	*-wrs)
+		os=vxworks
+		;;
+	*)
+		os=none
+		;;
+esac
+
+fi
+
+# Now, validate our (potentially fixed-up) individual pieces (OS, OBJ).
+
+case $os in
+	# Sometimes we do "kernel-libc", so those need to count as OSes.
+	musl* | newlib* | relibc* | uclibc*)
+		;;
+	# Likewise for "kernel-abi"
+	eabi* | gnueabi*)
+		;;
+	# VxWorks passes extra cpu info in the 4th filed.
+	simlinux | simwindows | spe)
+		;;
+	# See `case $cpu-$os` validation below
+	ghcjs)
+		;;
+	# Now accept the basic system types.
+	# The portable systems comes first.
+	# Each alternative MUST end in a * to match a version number.
+	gnu* | android* | bsd* | mach* | minix* | genix* | ultrix* | irix* \
+	     | *vms* | esix* | aix* | cnk* | sunos | sunos[34]* \
+	     | hpux* | unos* | osf* | luna* | dgux* | auroraux* | solaris* \
+	     | sym* |  plan9* | psp* | sim* | xray* | os68k* | v88r* \
+	     | hiux* | abug | nacl* | netware* | windows* \
+	     | os9* | macos* | osx* | ios* | tvos* | watchos* \
+	     | mpw* | magic* | mmixware* | mon960* | lnews* \
+	     | amigaos* | amigados* | msdos* | newsos* | unicos* | aof* \
+	     | aos* | aros* | cloudabi* | sortix* | twizzler* \
+	     | nindy* | vxsim* | vxworks* | ebmon* | hms* | mvs* \
+	     | clix* | riscos* | uniplus* | iris* | isc* | rtu* | xenix* \
+	     | mirbsd* | netbsd* | dicos* | openedition* | ose* \
+	     | bitrig* | openbsd* | secbsd* | solidbsd* | libertybsd* | os108* \
+	     | ekkobsd* | freebsd* | riscix* | lynxos* | os400* \
+	     | bosx* | nextstep* | cxux* | oabi* \
+	     | ptx* | ecoff* | winnt* | domain* | vsta* \
+	     | udi* | lites* | ieee* | go32* | aux* | hcos* \
+	     | chorusrdb* | cegcc* | glidix* | serenity* \
+	     | cygwin* | msys* | moss* | proelf* | rtems* \
+	     | midipix* | mingw32* | mingw64* | mint* \
+	     | uxpv* | beos* | mpeix* | udk* | moxiebox* \
+	     | interix* | uwin* | mks* | rhapsody* | darwin* \
+	     | openstep* | oskit* | conix* | pw32* | nonstopux* \
+	     | storm-chaos* | tops10* | tenex* | tops20* | its* \
+	     | os2* | vos* | palmos* | uclinux* | nucleus* | morphos* \
+	     | scout* | superux* | sysv* | rtmk* | tpf* | windiss* \
+	     | powermax* | dnix* | nx6 | nx7 | sei* | dragonfly* \
+	     | skyos* | haiku* | rdos* | toppers* | drops* | es* \
+	     | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
+	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
+	     | nsk* | powerunix* | genode* | zvmoe* | qnx* | emx* | zephyr* \
+	     | fiwix* | mlibc* | cos* | mbr* )
+		;;
+	# This one is extra strict with allowed versions
+	sco3.2v2 | sco3.2v[4-9]* | sco5v6*)
+		# Don't forget version if it is 3.2v4 or newer.
+		;;
+	none)
+		;;
+	kernel* | msvc* )
+		# Restricted further below
+		;;
+	'')
+		if test x"$obj" = x
+		then
+			echo "Invalid configuration '$1': Blank OS only allowed with explicit machine code file format" 1>&2
+		fi
+		;;
+	*)
+		echo "Invalid configuration '$1': OS '$os' not recognized" 1>&2
+		exit 1
+		;;
+esac
+
+case $obj in
+	aout* | coff* | elf* | pe*)
+		;;
+	'')
+		# empty is fine
+		;;
+	*)
+		echo "Invalid configuration '$1': Machine code format '$obj' not recognized" 1>&2
+		exit 1
+		;;
+esac
+
+# Here we handle the constraint that a (synthetic) cpu and os are
+# valid only in combination with each other and nowhere else.
+case $cpu-$os in
+	# The "javascript-unknown-ghcjs" triple is used by GHC; we
+	# accept it here in order to tolerate that, but reject any
+	# variations.
+	javascript-ghcjs)
+		;;
+	javascript-* | *-ghcjs)
+		echo "Invalid configuration '$1': cpu '$cpu' is not valid with os '$os$obj'" 1>&2
+		exit 1
+		;;
+esac
+
+# As a final step for OS-related things, validate the OS-kernel combination
+# (given a valid OS), if there is a kernel.
+case $kernel-$os-$obj in
+	linux-gnu*- | linux-dietlibc*- | linux-android*- | linux-newlib*- \
+		   | linux-musl*- | linux-relibc*- | linux-uclibc*- | linux-mlibc*- )
+		;;
+	uclinux-uclibc*- )
+		;;
+	managarm-mlibc*- | managarm-kernel*- )
+		;;
+	windows*-msvc*-)
+		;;
+	-dietlibc*- | -newlib*- | -musl*- | -relibc*- | -uclibc*- | -mlibc*- )
+		# These are just libc implementations, not actual OSes, and thus
+		# require a kernel.
+		echo "Invalid configuration '$1': libc '$os' needs explicit kernel." 1>&2
+		exit 1
+		;;
+	-kernel*- )
+		echo "Invalid configuration '$1': '$os' needs explicit kernel." 1>&2
+		exit 1
+		;;
+	*-kernel*- )
+		echo "Invalid configuration '$1': '$kernel' does not support '$os'." 1>&2
+		exit 1
+		;;
+	*-msvc*- )
+		echo "Invalid configuration '$1': '$os' needs 'windows'." 1>&2
+		exit 1
+		;;
+	kfreebsd*-gnu*- | kopensolaris*-gnu*-)
+		;;
+	vxworks-simlinux- | vxworks-simwindows- | vxworks-spe-)
+		;;
+	nto-qnx*-)
+		;;
+	os2-emx-)
+		;;
+	*-eabi*- | *-gnueabi*-)
+		;;
+	none--*)
+		# None (no kernel, i.e. freestanding / bare metal),
+		# can be paired with an machine code file format
+		;;
+	-*-)
+		# Blank kernel with real OS is always fine.
+		;;
+	--*)
+		# Blank kernel and OS with real machine code file format is always fine.
+		;;
+	*-*-*)
+		echo "Invalid configuration '$1': Kernel '$kernel' not known to work with OS '$os'." 1>&2
+		exit 1
+		;;
+esac
+
+# Here we handle the case where we know the os, and the CPU type, but not the
+# manufacturer.  We pick the logical manufacturer.
+case $vendor in
+	unknown)
+		case $cpu-$os in
+			*-riscix*)
+				vendor=acorn
+				;;
+			*-sunos*)
+				vendor=sun
+				;;
+			*-cnk* | *-aix*)
+				vendor=ibm
+				;;
+			*-beos*)
+				vendor=be
+				;;
+			*-hpux*)
+				vendor=hp
+				;;
+			*-mpeix*)
+				vendor=hp
+				;;
+			*-hiux*)
+				vendor=hitachi
+				;;
+			*-unos*)
+				vendor=crds
+				;;
+			*-dgux*)
+				vendor=dg
+				;;
+			*-luna*)
+				vendor=omron
+				;;
+			*-genix*)
+				vendor=ns
+				;;
+			*-clix*)
+				vendor=intergraph
+				;;
+			*-mvs* | *-opened*)
+				vendor=ibm
+				;;
+			*-os400*)
+				vendor=ibm
+				;;
+			s390-* | s390x-*)
+				vendor=ibm
+				;;
+			*-ptx*)
+				vendor=sequent
+				;;
+			*-tpf*)
+				vendor=ibm
+				;;
+			*-vxsim* | *-vxworks* | *-windiss*)
+				vendor=wrs
+				;;
+			*-aux*)
+				vendor=apple
+				;;
+			*-hms*)
+				vendor=hitachi
+				;;
+			*-mpw* | *-macos*)
+				vendor=apple
+				;;
+			*-*mint | *-mint[0-9]* | *-*MiNT | *-MiNT[0-9]*)
+				vendor=atari
+				;;
+			*-vos*)
+				vendor=stratus
+				;;
+		esac
+		;;
+esac
+
+echo "$cpu-$vendor${kernel:+-$kernel}${os:+-$os}${obj:+-$obj}"
+exit
+
+# Local variables:
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "timestamp='"
+# time-stamp-format: "%:y-%02m-%02d"
+# time-stamp-end: "'"
+# End:
Index: /trunk/src/libs/libpng-1.6.45/configure
===================================================================
--- /trunk/src/libs/libpng-1.6.45/configure	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/configure	(revision 107811)
@@ -0,0 +1,17158 @@
+#! /bin/sh
+# Guess values for system-dependent variables and create Makefiles.
+# Generated by GNU Autoconf 2.72 for libpng 1.6.43.
+#
+# Report bugs to <png-mng-implement@lists.sourceforge.net>.
+#
+#
+# Copyright (C) 1992-1996, 1998-2017, 2020-2023 Free Software Foundation,
+# Inc.
+#
+#
+# This configure script is free software; the Free Software Foundation
+# gives unlimited permission to copy, distribute and modify it.
+## -------------------- ##
+## M4sh Initialization. ##
+## -------------------- ##
+
+# Be more Bourne compatible
+DUALCASE=1; export DUALCASE # for MKS sh
+if test ${ZSH_VERSION+y} && (emulate sh) >/dev/null 2>&1
+then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else case e in #(
+  e) case `(set -o) 2>/dev/null` in #(
+  *posix*) :
+    set -o posix ;; #(
+  *) :
+     ;;
+esac ;;
+esac
+fi
+
+
+
+# Reset variables that may have inherited troublesome values from
+# the environment.
+
+# IFS needs to be set, to space, tab, and newline, in precisely that order.
+# (If _AS_PATH_WALK were called with IFS unset, it would have the
+# side effect of setting IFS to empty, thus disabling word splitting.)
+# Quoting is to prevent editors from complaining about space-tab.
+as_nl='
+'
+export as_nl
+IFS=" ""	$as_nl"
+
+PS1='$ '
+PS2='> '
+PS4='+ '
+
+# Ensure predictable behavior from utilities with locale-dependent output.
+LC_ALL=C
+export LC_ALL
+LANGUAGE=C
+export LANGUAGE
+
+# We cannot yet rely on "unset" to work, but we need these variables
+# to be unset--not just set to an empty or harmless value--now, to
+# avoid bugs in old shells (e.g. pre-3.0 UWIN ksh).  This construct
+# also avoids known problems related to "unset" and subshell syntax
+# in other old shells (e.g. bash 2.01 and pdksh 5.2.14).
+for as_var in BASH_ENV ENV MAIL MAILPATH CDPATH
+do eval test \${$as_var+y} \
+  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
+done
+
+# Ensure that fds 0, 1, and 2 are open.
+if (exec 3>&0) 2>/dev/null; then :; else exec 0</dev/null; fi
+if (exec 3>&1) 2>/dev/null; then :; else exec 1>/dev/null; fi
+if (exec 3>&2)            ; then :; else exec 2>/dev/null; fi
+
+# The user is always right.
+if ${PATH_SEPARATOR+false} :; then
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
+    (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
+      PATH_SEPARATOR=';'
+  }
+fi
+
+
+# Find who we are.  Look in the path if we contain no directory separator.
+as_myself=
+case $0 in #((
+  *[\\/]* ) as_myself=$0 ;;
+  *) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    test -r "$as_dir$0" && as_myself=$as_dir$0 && break
+  done
+IFS=$as_save_IFS
+
+     ;;
+esac
+# We did not find ourselves, most probably we were run as 'sh COMMAND'
+# in which case we are not to be found in the path.
+if test "x$as_myself" = x; then
+  as_myself=$0
+fi
+if test ! -f "$as_myself"; then
+  printf "%s\n" "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
+  exit 1
+fi
+
+
+# Use a proper internal environment variable to ensure we don't fall
+  # into an infinite loop, continuously re-executing ourselves.
+  if test x"${_as_can_reexec}" != xno && test "x$CONFIG_SHELL" != x; then
+    _as_can_reexec=no; export _as_can_reexec;
+    # We cannot yet assume a decent shell, so we have to provide a
+# neutralization value for shells without unset; and this also
+# works around shells that cannot unset nonexistent variables.
+# Preserve -v and -x to the replacement shell.
+BASH_ENV=/dev/null
+ENV=/dev/null
+(unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV
+case $- in # ((((
+  *v*x* | *x*v* ) as_opts=-vx ;;
+  *v* ) as_opts=-v ;;
+  *x* ) as_opts=-x ;;
+  * ) as_opts= ;;
+esac
+exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"}
+# Admittedly, this is quite paranoid, since all the known shells bail
+# out after a failed 'exec'.
+printf "%s\n" "$0: could not re-execute with $CONFIG_SHELL" >&2
+exit 255
+  fi
+  # We don't want this to propagate to other subprocesses.
+          { _as_can_reexec=; unset _as_can_reexec;}
+if test "x$CONFIG_SHELL" = x; then
+  as_bourne_compatible="if test \${ZSH_VERSION+y} && (emulate sh) >/dev/null 2>&1
+then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on \${1+\"\$@\"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '\${1+\"\$@\"}'='\"\$@\"'
+  setopt NO_GLOB_SUBST
+else case e in #(
+  e) case \`(set -o) 2>/dev/null\` in #(
+  *posix*) :
+    set -o posix ;; #(
+  *) :
+     ;;
+esac ;;
+esac
+fi
+"
+  as_required="as_fn_return () { (exit \$1); }
+as_fn_success () { as_fn_return 0; }
+as_fn_failure () { as_fn_return 1; }
+as_fn_ret_success () { return 0; }
+as_fn_ret_failure () { return 1; }
+
+exitcode=0
+as_fn_success || { exitcode=1; echo as_fn_success failed.; }
+as_fn_failure && { exitcode=1; echo as_fn_failure succeeded.; }
+as_fn_ret_success || { exitcode=1; echo as_fn_ret_success failed.; }
+as_fn_ret_failure && { exitcode=1; echo as_fn_ret_failure succeeded.; }
+if ( set x; as_fn_ret_success y && test x = \"\$1\" )
+then :
+
+else case e in #(
+  e) exitcode=1; echo positional parameters were not saved. ;;
+esac
+fi
+test x\$exitcode = x0 || exit 1
+blah=\$(echo \$(echo blah))
+test x\"\$blah\" = xblah || exit 1
+test -x / || exit 1"
+  as_suggested="  as_lineno_1=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_1a=\$LINENO
+  as_lineno_2=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_2a=\$LINENO
+  eval 'test \"x\$as_lineno_1'\$as_run'\" != \"x\$as_lineno_2'\$as_run'\" &&
+  test \"x\`expr \$as_lineno_1'\$as_run' + 1\`\" = \"x\$as_lineno_2'\$as_run'\"' || exit 1
+test \$(( 1 + 1 )) = 2 || exit 1
+
+  test -n \"\${ZSH_VERSION+set}\${BASH_VERSION+set}\" || (
+    ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
+    ECHO=\$ECHO\$ECHO\$ECHO\$ECHO\$ECHO
+    ECHO=\$ECHO\$ECHO\$ECHO\$ECHO\$ECHO\$ECHO
+    PATH=/empty FPATH=/empty; export PATH FPATH
+    test \"X\`printf %s \$ECHO\`\" = \"X\$ECHO\" \\
+      || test \"X\`print -r -- \$ECHO\`\" = \"X\$ECHO\" ) || exit 1"
+  if (eval "$as_required") 2>/dev/null
+then :
+  as_have_required=yes
+else case e in #(
+  e) as_have_required=no ;;
+esac
+fi
+  if test x$as_have_required = xyes && (eval "$as_suggested") 2>/dev/null
+then :
+
+else case e in #(
+  e) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+as_found=false
+for as_dir in /bin$PATH_SEPARATOR/usr/bin$PATH_SEPARATOR$PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+  as_found=:
+  case $as_dir in #(
+	 /*)
+	   for as_base in sh bash ksh sh5; do
+	     # Try only shells that exist, to save several forks.
+	     as_shell=$as_dir$as_base
+	     if { test -f "$as_shell" || test -f "$as_shell.exe"; } &&
+		    as_run=a "$as_shell" -c "$as_bourne_compatible""$as_required" 2>/dev/null
+then :
+  CONFIG_SHELL=$as_shell as_have_required=yes
+		   if as_run=a "$as_shell" -c "$as_bourne_compatible""$as_suggested" 2>/dev/null
+then :
+  break 2
+fi
+fi
+	   done;;
+       esac
+  as_found=false
+done
+IFS=$as_save_IFS
+if $as_found
+then :
+
+else case e in #(
+  e) if { test -f "$SHELL" || test -f "$SHELL.exe"; } &&
+	      as_run=a "$SHELL" -c "$as_bourne_compatible""$as_required" 2>/dev/null
+then :
+  CONFIG_SHELL=$SHELL as_have_required=yes
+fi ;;
+esac
+fi
+
+
+      if test "x$CONFIG_SHELL" != x
+then :
+  export CONFIG_SHELL
+             # We cannot yet assume a decent shell, so we have to provide a
+# neutralization value for shells without unset; and this also
+# works around shells that cannot unset nonexistent variables.
+# Preserve -v and -x to the replacement shell.
+BASH_ENV=/dev/null
+ENV=/dev/null
+(unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV
+case $- in # ((((
+  *v*x* | *x*v* ) as_opts=-vx ;;
+  *v* ) as_opts=-v ;;
+  *x* ) as_opts=-x ;;
+  * ) as_opts= ;;
+esac
+exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"}
+# Admittedly, this is quite paranoid, since all the known shells bail
+# out after a failed 'exec'.
+printf "%s\n" "$0: could not re-execute with $CONFIG_SHELL" >&2
+exit 255
+fi
+
+    if test x$as_have_required = xno
+then :
+  printf "%s\n" "$0: This script requires a shell more modern than all"
+  printf "%s\n" "$0: the shells that I found on your system."
+  if test ${ZSH_VERSION+y} ; then
+    printf "%s\n" "$0: In particular, zsh $ZSH_VERSION has bugs and should"
+    printf "%s\n" "$0: be upgraded to zsh 4.3.4 or later."
+  else
+    printf "%s\n" "$0: Please tell bug-autoconf@gnu.org and
+$0: png-mng-implement@lists.sourceforge.net about your
+$0: system, including any error possibly output before this
+$0: message. Then install a modern shell, or manually run
+$0: the script under such a shell if you do have one."
+  fi
+  exit 1
+fi ;;
+esac
+fi
+fi
+SHELL=${CONFIG_SHELL-/bin/sh}
+export SHELL
+# Unset more variables known to interfere with behavior of common tools.
+CLICOLOR_FORCE= GREP_OPTIONS=
+unset CLICOLOR_FORCE GREP_OPTIONS
+
+## --------------------- ##
+## M4sh Shell Functions. ##
+## --------------------- ##
+# as_fn_unset VAR
+# ---------------
+# Portably unset VAR.
+as_fn_unset ()
+{
+  { eval $1=; unset $1;}
+}
+as_unset=as_fn_unset
+
+
+# as_fn_set_status STATUS
+# -----------------------
+# Set $? to STATUS, without forking.
+as_fn_set_status ()
+{
+  return $1
+} # as_fn_set_status
+
+# as_fn_exit STATUS
+# -----------------
+# Exit the shell with STATUS, even in a "trap 0" or "set -e" context.
+as_fn_exit ()
+{
+  set +e
+  as_fn_set_status $1
+  exit $1
+} # as_fn_exit
+
+# as_fn_mkdir_p
+# -------------
+# Create "$as_dir" as a directory, including parents if necessary.
+as_fn_mkdir_p ()
+{
+
+  case $as_dir in #(
+  -*) as_dir=./$as_dir;;
+  esac
+  test -d "$as_dir" || eval $as_mkdir_p || {
+    as_dirs=
+    while :; do
+      case $as_dir in #(
+      *\'*) as_qdir=`printf "%s\n" "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
+      *) as_qdir=$as_dir;;
+      esac
+      as_dirs="'$as_qdir' $as_dirs"
+      as_dir=`$as_dirname -- "$as_dir" ||
+$as_expr X"$as_dir" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$as_dir" : 'X\(//\)[^/]' \| \
+	 X"$as_dir" : 'X\(//\)$' \| \
+	 X"$as_dir" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$as_dir" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+      test -d "$as_dir" && break
+    done
+    test -z "$as_dirs" || eval "mkdir $as_dirs"
+  } || test -d "$as_dir" || as_fn_error $? "cannot create directory $as_dir"
+
+
+} # as_fn_mkdir_p
+
+# as_fn_executable_p FILE
+# -----------------------
+# Test if FILE is an executable regular file.
+as_fn_executable_p ()
+{
+  test -f "$1" && test -x "$1"
+} # as_fn_executable_p
+# as_fn_append VAR VALUE
+# ----------------------
+# Append the text in VALUE to the end of the definition contained in VAR. Take
+# advantage of any shell optimizations that allow amortized linear growth over
+# repeated appends, instead of the typical quadratic growth present in naive
+# implementations.
+if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null
+then :
+  eval 'as_fn_append ()
+  {
+    eval $1+=\$2
+  }'
+else case e in #(
+  e) as_fn_append ()
+  {
+    eval $1=\$$1\$2
+  } ;;
+esac
+fi # as_fn_append
+
+# as_fn_arith ARG...
+# ------------------
+# Perform arithmetic evaluation on the ARGs, and store the result in the
+# global $as_val. Take advantage of shells that can avoid forks. The arguments
+# must be portable across $(()) and expr.
+if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null
+then :
+  eval 'as_fn_arith ()
+  {
+    as_val=$(( $* ))
+  }'
+else case e in #(
+  e) as_fn_arith ()
+  {
+    as_val=`expr "$@" || test $? -eq 1`
+  } ;;
+esac
+fi # as_fn_arith
+
+
+# as_fn_error STATUS ERROR [LINENO LOG_FD]
+# ----------------------------------------
+# Output "`basename $0`: error: ERROR" to stderr. If LINENO and LOG_FD are
+# provided, also output the error to LOG_FD, referencing LINENO. Then exit the
+# script with STATUS, using 1 if that was 0.
+as_fn_error ()
+{
+  as_status=$1; test $as_status -eq 0 && as_status=1
+  if test "$4"; then
+    as_lineno=${as_lineno-"$3"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
+  fi
+  printf "%s\n" "$as_me: error: $2" >&2
+  as_fn_exit $as_status
+} # as_fn_error
+
+if expr a : '\(a\)' >/dev/null 2>&1 &&
+   test "X`expr 00001 : '.*\(...\)'`" = X001; then
+  as_expr=expr
+else
+  as_expr=false
+fi
+
+if (basename -- /) >/dev/null 2>&1 && test "X`basename -- / 2>&1`" = "X/"; then
+  as_basename=basename
+else
+  as_basename=false
+fi
+
+if (as_dir=`dirname -- /` && test "X$as_dir" = X/) >/dev/null 2>&1; then
+  as_dirname=dirname
+else
+  as_dirname=false
+fi
+
+as_me=`$as_basename -- "$0" ||
+$as_expr X/"$0" : '.*/\([^/][^/]*\)/*$' \| \
+	 X"$0" : 'X\(//\)$' \| \
+	 X"$0" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X/"$0" |
+    sed '/^.*\/\([^/][^/]*\)\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+
+# Avoid depending upon Character Ranges.
+as_cr_letters='abcdefghijklmnopqrstuvwxyz'
+as_cr_LETTERS='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+as_cr_Letters=$as_cr_letters$as_cr_LETTERS
+as_cr_digits='0123456789'
+as_cr_alnum=$as_cr_Letters$as_cr_digits
+
+
+  as_lineno_1=$LINENO as_lineno_1a=$LINENO
+  as_lineno_2=$LINENO as_lineno_2a=$LINENO
+  eval 'test "x$as_lineno_1'$as_run'" != "x$as_lineno_2'$as_run'" &&
+  test "x`expr $as_lineno_1'$as_run' + 1`" = "x$as_lineno_2'$as_run'"' || {
+  # Blame Lee E. McMahon (1931-1989) for sed's syntax.  :-)
+  sed -n '
+    p
+    /[$]LINENO/=
+  ' <$as_myself |
+    sed '
+      t clear
+      :clear
+      s/[$]LINENO.*/&-/
+      t lineno
+      b
+      :lineno
+      N
+      :loop
+      s/[$]LINENO\([^'$as_cr_alnum'_].*\n\)\(.*\)/\2\1\2/
+      t loop
+      s/-\n.*//
+    ' >$as_me.lineno &&
+  chmod +x "$as_me.lineno" ||
+    { printf "%s\n" "$as_me: error: cannot create $as_me.lineno; rerun with a POSIX shell" >&2; as_fn_exit 1; }
+
+  # If we had to re-execute with $CONFIG_SHELL, we're ensured to have
+  # already done that, so ensure we don't try to do so again and fall
+  # in an infinite loop.  This has already happened in practice.
+  _as_can_reexec=no; export _as_can_reexec
+  # Don't try to exec as it changes $[0], causing all sort of problems
+  # (the dirname of $[0] is not the place where we might find the
+  # original and so on.  Autoconf is especially sensitive to this).
+  . "./$as_me.lineno"
+  # Exit status is that of the last command.
+  exit
+}
+
+
+# Determine whether it's possible to make 'echo' print without a newline.
+# These variables are no longer used directly by Autoconf, but are AC_SUBSTed
+# for compatibility with existing Makefiles.
+ECHO_C= ECHO_N= ECHO_T=
+case `echo -n x` in #(((((
+-n*)
+  case `echo 'xy\c'` in
+  *c*) ECHO_T='	';;	# ECHO_T is single tab character.
+  xy)  ECHO_C='\c';;
+  *)   echo `echo ksh88 bug on AIX 6.1` > /dev/null
+       ECHO_T='	';;
+  esac;;
+*)
+  ECHO_N='-n';;
+esac
+
+# For backward compatibility with old third-party macros, we provide
+# the shell variables $as_echo and $as_echo_n.  New code should use
+# AS_ECHO(["message"]) and AS_ECHO_N(["message"]), respectively.
+as_echo='printf %s\n'
+as_echo_n='printf %s'
+
+rm -f conf$$ conf$$.exe conf$$.file
+if test -d conf$$.dir; then
+  rm -f conf$$.dir/conf$$.file
+else
+  rm -f conf$$.dir
+  mkdir conf$$.dir 2>/dev/null
+fi
+if (echo >conf$$.file) 2>/dev/null; then
+  if ln -s conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s='ln -s'
+    # ... but there are two gotchas:
+    # 1) On MSYS, both 'ln -s file dir' and 'ln file dir' fail.
+    # 2) DJGPP < 2.04 has no symlinks; 'ln -s' creates a wrapper executable.
+    # In both cases, we have to default to 'cp -pR'.
+    ln -s conf$$.file conf$$.dir 2>/dev/null && test ! -f conf$$.exe ||
+      as_ln_s='cp -pR'
+  elif ln conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s=ln
+  else
+    as_ln_s='cp -pR'
+  fi
+else
+  as_ln_s='cp -pR'
+fi
+rm -f conf$$ conf$$.exe conf$$.dir/conf$$.file conf$$.file
+rmdir conf$$.dir 2>/dev/null
+
+if mkdir -p . 2>/dev/null; then
+  as_mkdir_p='mkdir -p "$as_dir"'
+else
+  test -d ./-p && rmdir ./-p
+  as_mkdir_p=false
+fi
+
+as_test_x='test -x'
+as_executable_p=as_fn_executable_p
+
+# Sed expression to map a string onto a valid CPP name.
+as_sed_cpp="y%*$as_cr_letters%P$as_cr_LETTERS%;s%[^_$as_cr_alnum]%_%g"
+as_tr_cpp="eval sed '$as_sed_cpp'" # deprecated
+
+# Sed expression to map a string onto a valid variable name.
+as_sed_sh="y%*+%pp%;s%[^_$as_cr_alnum]%_%g"
+as_tr_sh="eval sed '$as_sed_sh'" # deprecated
+
+SHELL=${CONFIG_SHELL-/bin/sh}
+
+
+test -n "$DJDIR" || exec 7<&0 </dev/null
+exec 6>&1
+
+# Name of the host.
+# hostname on some systems (SVR3.2, old GNU/Linux) returns a bogus exit status,
+# so uname gets run too.
+ac_hostname=`(hostname || uname -n) 2>/dev/null | sed 1q`
+
+#
+# Initializations.
+#
+ac_default_prefix=/usr/local
+ac_clean_files=
+ac_config_libobj_dir=.
+LIBOBJS=
+cross_compiling=no
+subdirs=
+MFLAGS=
+MAKEFLAGS=
+
+# Identity of this package.
+PACKAGE_NAME='libpng'
+PACKAGE_TARNAME='libpng'
+PACKAGE_VERSION='1.6.43'
+PACKAGE_STRING='libpng 1.6.43'
+PACKAGE_BUGREPORT='png-mng-implement@lists.sourceforge.net'
+PACKAGE_URL=''
+
+ac_unique_file="pngget.c"
+# Factoring default headers for most tests.
+ac_includes_default="\
+#include <stddef.h>
+#ifdef HAVE_STDIO_H
+# include <stdio.h>
+#endif
+#ifdef HAVE_STDLIB_H
+# include <stdlib.h>
+#endif
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+# include <inttypes.h>
+#endif
+#ifdef HAVE_STDINT_H
+# include <stdint.h>
+#endif
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif"
+
+ac_header_c_list=
+ac_subst_vars='am__EXEEXT_FALSE
+am__EXEEXT_TRUE
+LTLIBOBJS
+LIBOBJS
+PNG_LOONGARCH_LSX_FALSE
+PNG_LOONGARCH_LSX_TRUE
+PNG_POWERPC_VSX_FALSE
+PNG_POWERPC_VSX_TRUE
+PNG_INTEL_SSE_FALSE
+PNG_INTEL_SSE_TRUE
+PNG_MIPS_MMI_FALSE
+PNG_MIPS_MMI_TRUE
+PNG_MIPS_MSA_FALSE
+PNG_MIPS_MSA_TRUE
+PNG_ARM_NEON_FALSE
+PNG_ARM_NEON_TRUE
+DO_INSTALL_LIBPNG_CONFIG_FALSE
+DO_INSTALL_LIBPNG_CONFIG_TRUE
+DO_INSTALL_LIBPNG_PC_FALSE
+DO_INSTALL_LIBPNG_PC_TRUE
+DO_INSTALL_LINKS_FALSE
+DO_INSTALL_LINKS_TRUE
+DO_PNG_PREFIX_FALSE
+DO_PNG_PREFIX_TRUE
+PNG_PREFIX
+binconfigs
+pkgconfigdir
+PNGLIB_RELEASE
+PNGLIB_MINOR
+PNGLIB_MAJOR
+PNGLIB_VERSION
+SYMBOL_PREFIX
+HAVE_LD_VERSION_SCRIPT_FALSE
+HAVE_LD_VERSION_SCRIPT_TRUE
+HAVE_SOLARIS_LD_FALSE
+HAVE_SOLARIS_LD_TRUE
+HAVE_CLOCK_GETTIME_FALSE
+HAVE_CLOCK_GETTIME_TRUE
+PNG_COPTS
+ENABLE_TOOLS_FALSE
+ENABLE_TOOLS_TRUE
+ENABLE_TESTS_FALSE
+ENABLE_TESTS_TRUE
+DFNCPP
+LT_SYS_LIBRARY_PATH
+OTOOL64
+OTOOL
+LIPO
+NMEDIT
+DSYMUTIL
+MANIFEST_TOOL
+RANLIB
+ac_ct_AR
+AR
+FILECMD
+NM
+ac_ct_DUMPBIN
+DUMPBIN
+LIBTOOL
+OBJDUMP
+DLLTOOL
+AS
+LN_S
+CPP
+LD
+FGREP
+EGREP
+GREP
+SED
+host_os
+host_vendor
+host_cpu
+host
+build_os
+build_vendor
+build_cpu
+build
+am__fastdepCCAS_FALSE
+am__fastdepCCAS_TRUE
+CCASDEPMODE
+CCASFLAGS
+CCAS
+am__fastdepCC_FALSE
+am__fastdepCC_TRUE
+CCDEPMODE
+am__nodep
+AMDEPBACKSLASH
+AMDEP_FALSE
+AMDEP_TRUE
+am__include
+DEPDIR
+OBJEXT
+EXEEXT
+ac_ct_CC
+CPPFLAGS
+LDFLAGS
+CFLAGS
+CC
+MAINT
+MAINTAINER_MODE_FALSE
+MAINTAINER_MODE_TRUE
+AM_BACKSLASH
+AM_DEFAULT_VERBOSITY
+AM_DEFAULT_V
+AM_V
+CSCOPE
+ETAGS
+CTAGS
+am__untar
+am__tar
+AMTAR
+am__leading_dot
+SET_MAKE
+AWK
+mkdir_p
+MKDIR_P
+INSTALL_STRIP_PROGRAM
+STRIP
+install_sh
+MAKEINFO
+AUTOHEADER
+AUTOMAKE
+AUTOCONF
+ACLOCAL
+VERSION
+PACKAGE
+CYGPATH_W
+am__isrc
+INSTALL_DATA
+INSTALL_SCRIPT
+INSTALL_PROGRAM
+target_alias
+host_alias
+build_alias
+LIBS
+ECHO_T
+ECHO_N
+ECHO_C
+DEFS
+mandir
+localedir
+libdir
+psdir
+pdfdir
+dvidir
+htmldir
+infodir
+docdir
+oldincludedir
+includedir
+runstatedir
+localstatedir
+sharedstatedir
+sysconfdir
+datadir
+datarootdir
+libexecdir
+sbindir
+bindir
+program_transform_name
+prefix
+exec_prefix
+PACKAGE_URL
+PACKAGE_BUGREPORT
+PACKAGE_STRING
+PACKAGE_VERSION
+PACKAGE_TARNAME
+PACKAGE_NAME
+PATH_SEPARATOR
+SHELL
+am__quote'
+ac_subst_files=''
+ac_user_opts='
+enable_option_checking
+enable_silent_rules
+enable_maintainer_mode
+enable_dependency_tracking
+with_gnu_ld
+enable_shared
+enable_static
+with_pic
+enable_fast_install
+with_aix_soname
+with_sysroot
+enable_libtool_lock
+enable_tests
+enable_tools
+enable_werror
+with_zlib_prefix
+with_pkgconfigdir
+with_binconfigs
+with_libpng_prefix
+enable_unversioned_links
+enable_unversioned_libpng_pc
+enable_unversioned_libpng_config
+enable_hardware_optimizations
+enable_arm_neon
+enable_mips_msa
+enable_mips_mmi
+enable_intel_sse
+enable_powerpc_vsx
+enable_loongarch_lsx
+'
+      ac_precious_vars='build_alias
+host_alias
+target_alias
+CC
+CFLAGS
+LDFLAGS
+LIBS
+CPPFLAGS
+CCAS
+CCASFLAGS
+CPP
+LT_SYS_LIBRARY_PATH
+AWK
+PNG_COPTS'
+
+
+# Initialize some variables set by options.
+ac_init_help=
+ac_init_version=false
+ac_unrecognized_opts=
+ac_unrecognized_sep=
+# The variables have the same names as the options, with
+# dashes changed to underlines.
+cache_file=/dev/null
+exec_prefix=NONE
+no_create=
+no_recursion=
+prefix=NONE
+program_prefix=NONE
+program_suffix=NONE
+program_transform_name=s,x,x,
+silent=
+site=
+srcdir=
+verbose=
+x_includes=NONE
+x_libraries=NONE
+
+# Installation directory options.
+# These are left unexpanded so users can "make install exec_prefix=/foo"
+# and all the variables that are supposed to be based on exec_prefix
+# by default will actually change.
+# Use braces instead of parens because sh, perl, etc. also accept them.
+# (The list follows the same order as the GNU Coding Standards.)
+bindir='${exec_prefix}/bin'
+sbindir='${exec_prefix}/sbin'
+libexecdir='${exec_prefix}/libexec'
+datarootdir='${prefix}/share'
+datadir='${datarootdir}'
+sysconfdir='${prefix}/etc'
+sharedstatedir='${prefix}/com'
+localstatedir='${prefix}/var'
+runstatedir='${localstatedir}/run'
+includedir='${prefix}/include'
+oldincludedir='/usr/include'
+docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
+infodir='${datarootdir}/info'
+htmldir='${docdir}'
+dvidir='${docdir}'
+pdfdir='${docdir}'
+psdir='${docdir}'
+libdir='${exec_prefix}/lib'
+localedir='${datarootdir}/locale'
+mandir='${datarootdir}/man'
+
+ac_prev=
+ac_dashdash=
+for ac_option
+do
+  # If the previous option needs an argument, assign it.
+  if test -n "$ac_prev"; then
+    eval $ac_prev=\$ac_option
+    ac_prev=
+    continue
+  fi
+
+  case $ac_option in
+  *=?*) ac_optarg=`expr "X$ac_option" : '[^=]*=\(.*\)'` ;;
+  *=)   ac_optarg= ;;
+  *)    ac_optarg=yes ;;
+  esac
+
+  case $ac_dashdash$ac_option in
+  --)
+    ac_dashdash=yes ;;
+
+  -bindir | --bindir | --bindi | --bind | --bin | --bi)
+    ac_prev=bindir ;;
+  -bindir=* | --bindir=* | --bindi=* | --bind=* | --bin=* | --bi=*)
+    bindir=$ac_optarg ;;
+
+  -build | --build | --buil | --bui | --bu)
+    ac_prev=build_alias ;;
+  -build=* | --build=* | --buil=* | --bui=* | --bu=*)
+    build_alias=$ac_optarg ;;
+
+  -cache-file | --cache-file | --cache-fil | --cache-fi \
+  | --cache-f | --cache- | --cache | --cach | --cac | --ca | --c)
+    ac_prev=cache_file ;;
+  -cache-file=* | --cache-file=* | --cache-fil=* | --cache-fi=* \
+  | --cache-f=* | --cache-=* | --cache=* | --cach=* | --cac=* | --ca=* | --c=*)
+    cache_file=$ac_optarg ;;
+
+  --config-cache | -C)
+    cache_file=config.cache ;;
+
+  -datadir | --datadir | --datadi | --datad)
+    ac_prev=datadir ;;
+  -datadir=* | --datadir=* | --datadi=* | --datad=*)
+    datadir=$ac_optarg ;;
+
+  -datarootdir | --datarootdir | --datarootdi | --datarootd | --dataroot \
+  | --dataroo | --dataro | --datar)
+    ac_prev=datarootdir ;;
+  -datarootdir=* | --datarootdir=* | --datarootdi=* | --datarootd=* \
+  | --dataroot=* | --dataroo=* | --dataro=* | --datar=*)
+    datarootdir=$ac_optarg ;;
+
+  -disable-* | --disable-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*disable-\(.*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid feature name: '$ac_useropt'"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"enable_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--disable-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval enable_$ac_useropt=no ;;
+
+  -docdir | --docdir | --docdi | --doc | --do)
+    ac_prev=docdir ;;
+  -docdir=* | --docdir=* | --docdi=* | --doc=* | --do=*)
+    docdir=$ac_optarg ;;
+
+  -dvidir | --dvidir | --dvidi | --dvid | --dvi | --dv)
+    ac_prev=dvidir ;;
+  -dvidir=* | --dvidir=* | --dvidi=* | --dvid=* | --dvi=* | --dv=*)
+    dvidir=$ac_optarg ;;
+
+  -enable-* | --enable-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*enable-\([^=]*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid feature name: '$ac_useropt'"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"enable_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--enable-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval enable_$ac_useropt=\$ac_optarg ;;
+
+  -exec-prefix | --exec_prefix | --exec-prefix | --exec-prefi \
+  | --exec-pref | --exec-pre | --exec-pr | --exec-p | --exec- \
+  | --exec | --exe | --ex)
+    ac_prev=exec_prefix ;;
+  -exec-prefix=* | --exec_prefix=* | --exec-prefix=* | --exec-prefi=* \
+  | --exec-pref=* | --exec-pre=* | --exec-pr=* | --exec-p=* | --exec-=* \
+  | --exec=* | --exe=* | --ex=*)
+    exec_prefix=$ac_optarg ;;
+
+  -gas | --gas | --ga | --g)
+    # Obsolete; use --with-gas.
+    with_gas=yes ;;
+
+  -help | --help | --hel | --he | -h)
+    ac_init_help=long ;;
+  -help=r* | --help=r* | --hel=r* | --he=r* | -hr*)
+    ac_init_help=recursive ;;
+  -help=s* | --help=s* | --hel=s* | --he=s* | -hs*)
+    ac_init_help=short ;;
+
+  -host | --host | --hos | --ho)
+    ac_prev=host_alias ;;
+  -host=* | --host=* | --hos=* | --ho=*)
+    host_alias=$ac_optarg ;;
+
+  -htmldir | --htmldir | --htmldi | --htmld | --html | --htm | --ht)
+    ac_prev=htmldir ;;
+  -htmldir=* | --htmldir=* | --htmldi=* | --htmld=* | --html=* | --htm=* \
+  | --ht=*)
+    htmldir=$ac_optarg ;;
+
+  -includedir | --includedir | --includedi | --included | --include \
+  | --includ | --inclu | --incl | --inc)
+    ac_prev=includedir ;;
+  -includedir=* | --includedir=* | --includedi=* | --included=* | --include=* \
+  | --includ=* | --inclu=* | --incl=* | --inc=*)
+    includedir=$ac_optarg ;;
+
+  -infodir | --infodir | --infodi | --infod | --info | --inf)
+    ac_prev=infodir ;;
+  -infodir=* | --infodir=* | --infodi=* | --infod=* | --info=* | --inf=*)
+    infodir=$ac_optarg ;;
+
+  -libdir | --libdir | --libdi | --libd)
+    ac_prev=libdir ;;
+  -libdir=* | --libdir=* | --libdi=* | --libd=*)
+    libdir=$ac_optarg ;;
+
+  -libexecdir | --libexecdir | --libexecdi | --libexecd | --libexec \
+  | --libexe | --libex | --libe)
+    ac_prev=libexecdir ;;
+  -libexecdir=* | --libexecdir=* | --libexecdi=* | --libexecd=* | --libexec=* \
+  | --libexe=* | --libex=* | --libe=*)
+    libexecdir=$ac_optarg ;;
+
+  -localedir | --localedir | --localedi | --localed | --locale)
+    ac_prev=localedir ;;
+  -localedir=* | --localedir=* | --localedi=* | --localed=* | --locale=*)
+    localedir=$ac_optarg ;;
+
+  -localstatedir | --localstatedir | --localstatedi | --localstated \
+  | --localstate | --localstat | --localsta | --localst | --locals)
+    ac_prev=localstatedir ;;
+  -localstatedir=* | --localstatedir=* | --localstatedi=* | --localstated=* \
+  | --localstate=* | --localstat=* | --localsta=* | --localst=* | --locals=*)
+    localstatedir=$ac_optarg ;;
+
+  -mandir | --mandir | --mandi | --mand | --man | --ma | --m)
+    ac_prev=mandir ;;
+  -mandir=* | --mandir=* | --mandi=* | --mand=* | --man=* | --ma=* | --m=*)
+    mandir=$ac_optarg ;;
+
+  -nfp | --nfp | --nf)
+    # Obsolete; use --without-fp.
+    with_fp=no ;;
+
+  -no-create | --no-create | --no-creat | --no-crea | --no-cre \
+  | --no-cr | --no-c | -n)
+    no_create=yes ;;
+
+  -no-recursion | --no-recursion | --no-recursio | --no-recursi \
+  | --no-recurs | --no-recur | --no-recu | --no-rec | --no-re | --no-r)
+    no_recursion=yes ;;
+
+  -oldincludedir | --oldincludedir | --oldincludedi | --oldincluded \
+  | --oldinclude | --oldinclud | --oldinclu | --oldincl | --oldinc \
+  | --oldin | --oldi | --old | --ol | --o)
+    ac_prev=oldincludedir ;;
+  -oldincludedir=* | --oldincludedir=* | --oldincludedi=* | --oldincluded=* \
+  | --oldinclude=* | --oldinclud=* | --oldinclu=* | --oldincl=* | --oldinc=* \
+  | --oldin=* | --oldi=* | --old=* | --ol=* | --o=*)
+    oldincludedir=$ac_optarg ;;
+
+  -prefix | --prefix | --prefi | --pref | --pre | --pr | --p)
+    ac_prev=prefix ;;
+  -prefix=* | --prefix=* | --prefi=* | --pref=* | --pre=* | --pr=* | --p=*)
+    prefix=$ac_optarg ;;
+
+  -program-prefix | --program-prefix | --program-prefi | --program-pref \
+  | --program-pre | --program-pr | --program-p)
+    ac_prev=program_prefix ;;
+  -program-prefix=* | --program-prefix=* | --program-prefi=* \
+  | --program-pref=* | --program-pre=* | --program-pr=* | --program-p=*)
+    program_prefix=$ac_optarg ;;
+
+  -program-suffix | --program-suffix | --program-suffi | --program-suff \
+  | --program-suf | --program-su | --program-s)
+    ac_prev=program_suffix ;;
+  -program-suffix=* | --program-suffix=* | --program-suffi=* \
+  | --program-suff=* | --program-suf=* | --program-su=* | --program-s=*)
+    program_suffix=$ac_optarg ;;
+
+  -program-transform-name | --program-transform-name \
+  | --program-transform-nam | --program-transform-na \
+  | --program-transform-n | --program-transform- \
+  | --program-transform | --program-transfor \
+  | --program-transfo | --program-transf \
+  | --program-trans | --program-tran \
+  | --progr-tra | --program-tr | --program-t)
+    ac_prev=program_transform_name ;;
+  -program-transform-name=* | --program-transform-name=* \
+  | --program-transform-nam=* | --program-transform-na=* \
+  | --program-transform-n=* | --program-transform-=* \
+  | --program-transform=* | --program-transfor=* \
+  | --program-transfo=* | --program-transf=* \
+  | --program-trans=* | --program-tran=* \
+  | --progr-tra=* | --program-tr=* | --program-t=*)
+    program_transform_name=$ac_optarg ;;
+
+  -pdfdir | --pdfdir | --pdfdi | --pdfd | --pdf | --pd)
+    ac_prev=pdfdir ;;
+  -pdfdir=* | --pdfdir=* | --pdfdi=* | --pdfd=* | --pdf=* | --pd=*)
+    pdfdir=$ac_optarg ;;
+
+  -psdir | --psdir | --psdi | --psd | --ps)
+    ac_prev=psdir ;;
+  -psdir=* | --psdir=* | --psdi=* | --psd=* | --ps=*)
+    psdir=$ac_optarg ;;
+
+  -q | -quiet | --quiet | --quie | --qui | --qu | --q \
+  | -silent | --silent | --silen | --sile | --sil)
+    silent=yes ;;
+
+  -runstatedir | --runstatedir | --runstatedi | --runstated \
+  | --runstate | --runstat | --runsta | --runst | --runs \
+  | --run | --ru | --r)
+    ac_prev=runstatedir ;;
+  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
+  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
+  | --run=* | --ru=* | --r=*)
+    runstatedir=$ac_optarg ;;
+
+  -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
+    ac_prev=sbindir ;;
+  -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
+  | --sbi=* | --sb=*)
+    sbindir=$ac_optarg ;;
+
+  -sharedstatedir | --sharedstatedir | --sharedstatedi \
+  | --sharedstated | --sharedstate | --sharedstat | --sharedsta \
+  | --sharedst | --shareds | --shared | --share | --shar \
+  | --sha | --sh)
+    ac_prev=sharedstatedir ;;
+  -sharedstatedir=* | --sharedstatedir=* | --sharedstatedi=* \
+  | --sharedstated=* | --sharedstate=* | --sharedstat=* | --sharedsta=* \
+  | --sharedst=* | --shareds=* | --shared=* | --share=* | --shar=* \
+  | --sha=* | --sh=*)
+    sharedstatedir=$ac_optarg ;;
+
+  -site | --site | --sit)
+    ac_prev=site ;;
+  -site=* | --site=* | --sit=*)
+    site=$ac_optarg ;;
+
+  -srcdir | --srcdir | --srcdi | --srcd | --src | --sr)
+    ac_prev=srcdir ;;
+  -srcdir=* | --srcdir=* | --srcdi=* | --srcd=* | --src=* | --sr=*)
+    srcdir=$ac_optarg ;;
+
+  -sysconfdir | --sysconfdir | --sysconfdi | --sysconfd | --sysconf \
+  | --syscon | --sysco | --sysc | --sys | --sy)
+    ac_prev=sysconfdir ;;
+  -sysconfdir=* | --sysconfdir=* | --sysconfdi=* | --sysconfd=* | --sysconf=* \
+  | --syscon=* | --sysco=* | --sysc=* | --sys=* | --sy=*)
+    sysconfdir=$ac_optarg ;;
+
+  -target | --target | --targe | --targ | --tar | --ta | --t)
+    ac_prev=target_alias ;;
+  -target=* | --target=* | --targe=* | --targ=* | --tar=* | --ta=* | --t=*)
+    target_alias=$ac_optarg ;;
+
+  -v | -verbose | --verbose | --verbos | --verbo | --verb)
+    verbose=yes ;;
+
+  -version | --version | --versio | --versi | --vers | -V)
+    ac_init_version=: ;;
+
+  -with-* | --with-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*with-\([^=]*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid package name: '$ac_useropt'"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"with_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--with-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval with_$ac_useropt=\$ac_optarg ;;
+
+  -without-* | --without-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*without-\(.*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid package name: '$ac_useropt'"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"with_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--without-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval with_$ac_useropt=no ;;
+
+  --x)
+    # Obsolete; use --with-x.
+    with_x=yes ;;
+
+  -x-includes | --x-includes | --x-include | --x-includ | --x-inclu \
+  | --x-incl | --x-inc | --x-in | --x-i)
+    ac_prev=x_includes ;;
+  -x-includes=* | --x-includes=* | --x-include=* | --x-includ=* | --x-inclu=* \
+  | --x-incl=* | --x-inc=* | --x-in=* | --x-i=*)
+    x_includes=$ac_optarg ;;
+
+  -x-libraries | --x-libraries | --x-librarie | --x-librari \
+  | --x-librar | --x-libra | --x-libr | --x-lib | --x-li | --x-l)
+    ac_prev=x_libraries ;;
+  -x-libraries=* | --x-libraries=* | --x-librarie=* | --x-librari=* \
+  | --x-librar=* | --x-libra=* | --x-libr=* | --x-lib=* | --x-li=* | --x-l=*)
+    x_libraries=$ac_optarg ;;
+
+  -*) as_fn_error $? "unrecognized option: '$ac_option'
+Try '$0 --help' for more information"
+    ;;
+
+  *=*)
+    ac_envvar=`expr "x$ac_option" : 'x\([^=]*\)='`
+    # Reject names that are not valid shell variable names.
+    case $ac_envvar in #(
+      '' | [0-9]* | *[!_$as_cr_alnum]* )
+      as_fn_error $? "invalid variable name: '$ac_envvar'" ;;
+    esac
+    eval $ac_envvar=\$ac_optarg
+    export $ac_envvar ;;
+
+  *)
+    # FIXME: should be removed in autoconf 3.0.
+    printf "%s\n" "$as_me: WARNING: you should use --build, --host, --target" >&2
+    expr "x$ac_option" : ".*[^-._$as_cr_alnum]" >/dev/null &&
+      printf "%s\n" "$as_me: WARNING: invalid host type: $ac_option" >&2
+    : "${build_alias=$ac_option} ${host_alias=$ac_option} ${target_alias=$ac_option}"
+    ;;
+
+  esac
+done
+
+if test -n "$ac_prev"; then
+  ac_option=--`echo $ac_prev | sed 's/_/-/g'`
+  as_fn_error $? "missing argument to $ac_option"
+fi
+
+if test -n "$ac_unrecognized_opts"; then
+  case $enable_option_checking in
+    no) ;;
+    fatal) as_fn_error $? "unrecognized options: $ac_unrecognized_opts" ;;
+    *)     printf "%s\n" "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2 ;;
+  esac
+fi
+
+# Check all directory arguments for consistency.
+for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
+		datadir sysconfdir sharedstatedir localstatedir includedir \
+		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
+		libdir localedir mandir runstatedir
+do
+  eval ac_val=\$$ac_var
+  # Remove trailing slashes.
+  case $ac_val in
+    */ )
+      ac_val=`expr "X$ac_val" : 'X\(.*[^/]\)' \| "X$ac_val" : 'X\(.*\)'`
+      eval $ac_var=\$ac_val;;
+  esac
+  # Be sure to have absolute directory names.
+  case $ac_val in
+    [\\/$]* | ?:[\\/]* )  continue;;
+    NONE | '' ) case $ac_var in *prefix ) continue;; esac;;
+  esac
+  as_fn_error $? "expected an absolute directory name for --$ac_var: $ac_val"
+done
+
+# There might be people who depend on the old broken behavior: '$host'
+# used to hold the argument of --host etc.
+# FIXME: To remove some day.
+build=$build_alias
+host=$host_alias
+target=$target_alias
+
+# FIXME: To remove some day.
+if test "x$host_alias" != x; then
+  if test "x$build_alias" = x; then
+    cross_compiling=maybe
+  elif test "x$build_alias" != "x$host_alias"; then
+    cross_compiling=yes
+  fi
+fi
+
+ac_tool_prefix=
+test -n "$host_alias" && ac_tool_prefix=$host_alias-
+
+test "$silent" = yes && exec 6>/dev/null
+
+
+ac_pwd=`pwd` && test -n "$ac_pwd" &&
+ac_ls_di=`ls -di .` &&
+ac_pwd_ls_di=`cd "$ac_pwd" && ls -di .` ||
+  as_fn_error $? "working directory cannot be determined"
+test "X$ac_ls_di" = "X$ac_pwd_ls_di" ||
+  as_fn_error $? "pwd does not report name of working directory"
+
+
+# Find the source files, if location was not specified.
+if test -z "$srcdir"; then
+  ac_srcdir_defaulted=yes
+  # Try the directory containing this script, then the parent directory.
+  ac_confdir=`$as_dirname -- "$as_myself" ||
+$as_expr X"$as_myself" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$as_myself" : 'X\(//\)[^/]' \| \
+	 X"$as_myself" : 'X\(//\)$' \| \
+	 X"$as_myself" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$as_myself" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+  srcdir=$ac_confdir
+  if test ! -r "$srcdir/$ac_unique_file"; then
+    srcdir=..
+  fi
+else
+  ac_srcdir_defaulted=no
+fi
+if test ! -r "$srcdir/$ac_unique_file"; then
+  test "$ac_srcdir_defaulted" = yes && srcdir="$ac_confdir or .."
+  as_fn_error $? "cannot find sources ($ac_unique_file) in $srcdir"
+fi
+ac_msg="sources are in $srcdir, but 'cd $srcdir' does not work"
+ac_abs_confdir=`(
+	cd "$srcdir" && test -r "./$ac_unique_file" || as_fn_error $? "$ac_msg"
+	pwd)`
+# When building in place, set srcdir=.
+if test "$ac_abs_confdir" = "$ac_pwd"; then
+  srcdir=.
+fi
+# Remove unnecessary trailing slashes from srcdir.
+# Double slashes in file names in object file debugging info
+# mess up M-x gdb in Emacs.
+case $srcdir in
+*/) srcdir=`expr "X$srcdir" : 'X\(.*[^/]\)' \| "X$srcdir" : 'X\(.*\)'`;;
+esac
+for ac_var in $ac_precious_vars; do
+  eval ac_env_${ac_var}_set=\${${ac_var}+set}
+  eval ac_env_${ac_var}_value=\$${ac_var}
+  eval ac_cv_env_${ac_var}_set=\${${ac_var}+set}
+  eval ac_cv_env_${ac_var}_value=\$${ac_var}
+done
+
+#
+# Report the --help message.
+#
+if test "$ac_init_help" = "long"; then
+  # Omit some internal or obsolete options to make the list less imposing.
+  # This message is too long to be a string in the A/UX 3.1 sh.
+  cat <<_ACEOF
+'configure' configures libpng 1.6.43 to adapt to many kinds of systems.
+
+Usage: $0 [OPTION]... [VAR=VALUE]...
+
+To assign environment variables (e.g., CC, CFLAGS...), specify them as
+VAR=VALUE.  See below for descriptions of some of the useful variables.
+
+Defaults for the options are specified in brackets.
+
+Configuration:
+  -h, --help              display this help and exit
+      --help=short        display options specific to this package
+      --help=recursive    display the short help of all the included packages
+  -V, --version           display version information and exit
+  -q, --quiet, --silent   do not print 'checking ...' messages
+      --cache-file=FILE   cache test results in FILE [disabled]
+  -C, --config-cache      alias for '--cache-file=config.cache'
+  -n, --no-create         do not create output files
+      --srcdir=DIR        find the sources in DIR [configure dir or '..']
+
+Installation directories:
+  --prefix=PREFIX         install architecture-independent files in PREFIX
+                          [$ac_default_prefix]
+  --exec-prefix=EPREFIX   install architecture-dependent files in EPREFIX
+                          [PREFIX]
+
+By default, 'make install' will install all the files in
+'$ac_default_prefix/bin', '$ac_default_prefix/lib' etc.  You can specify
+an installation prefix other than '$ac_default_prefix' using '--prefix',
+for instance '--prefix=\$HOME'.
+
+For better control, use the options below.
+
+Fine tuning of the installation directories:
+  --bindir=DIR            user executables [EPREFIX/bin]
+  --sbindir=DIR           system admin executables [EPREFIX/sbin]
+  --libexecdir=DIR        program executables [EPREFIX/libexec]
+  --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
+  --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
+  --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
+  --libdir=DIR            object code libraries [EPREFIX/lib]
+  --includedir=DIR        C header files [PREFIX/include]
+  --oldincludedir=DIR     C header files for non-gcc [/usr/include]
+  --datarootdir=DIR       read-only arch.-independent data root [PREFIX/share]
+  --datadir=DIR           read-only architecture-independent data [DATAROOTDIR]
+  --infodir=DIR           info documentation [DATAROOTDIR/info]
+  --localedir=DIR         locale-dependent data [DATAROOTDIR/locale]
+  --mandir=DIR            man documentation [DATAROOTDIR/man]
+  --docdir=DIR            documentation root [DATAROOTDIR/doc/libpng]
+  --htmldir=DIR           html documentation [DOCDIR]
+  --dvidir=DIR            dvi documentation [DOCDIR]
+  --pdfdir=DIR            pdf documentation [DOCDIR]
+  --psdir=DIR             ps documentation [DOCDIR]
+_ACEOF
+
+  cat <<\_ACEOF
+
+Program names:
+  --program-prefix=PREFIX            prepend PREFIX to installed program names
+  --program-suffix=SUFFIX            append SUFFIX to installed program names
+  --program-transform-name=PROGRAM   run sed PROGRAM on installed program names
+
+System types:
+  --build=BUILD     configure for building on BUILD [guessed]
+  --host=HOST       cross-compile to build programs to run on HOST [BUILD]
+_ACEOF
+fi
+
+if test -n "$ac_init_help"; then
+  case $ac_init_help in
+     short | recursive ) echo "Configuration of libpng 1.6.43:";;
+   esac
+  cat <<\_ACEOF
+
+Optional Features:
+  --disable-option-checking  ignore unrecognized --enable/--with options
+  --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
+  --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
+  --enable-silent-rules   less verbose build output (undo: "make V=1")
+  --disable-silent-rules  verbose build output (undo: "make V=0")
+  --enable-maintainer-mode
+                          enable make rules and dependencies not useful (and
+                          sometimes confusing) to the casual installer
+  --enable-dependency-tracking
+                          do not reject slow dependency extractors
+  --disable-dependency-tracking
+                          speeds up one-time build
+  --enable-shared[=PKGS]  build shared libraries [default=yes]
+  --enable-static[=PKGS]  build static libraries [default=yes]
+  --enable-fast-install[=PKGS]
+                          optimize for fast installation [default=yes]
+  --disable-libtool-lock  avoid locking (might break parallel builds)
+  --disable-tests         do not build the test programs (default is to build)
+  --disable-tools         do not build the auxiliary tools (default is to
+                          build)
+  --enable-werror[=OPT] Pass -Werror or the given argument to the compiler
+                          if it is supported
+  --enable-unversioned-links
+                          Installed libpng header files are placed in a
+                          versioned subdirectory and installed libpng library
+                          (including DLL) files are versioned. If this option
+                          is enabled unversioned links will be created
+                          pointing to the corresponding installed files. If
+                          you use libpng.pc or libpng-config for all builds
+                          you do not need these links, but if you compile
+                          programs directly they will typically #include
+                          <png.h> and link with -lpng; in that case you need
+                          the links. The links can be installed manually using
+                          'make install-header-links' and 'make
+                          install-library-links' and can be removed using the
+                          corresponding uninstall- targets. If you do enable
+                          this option every libpng 'make install' will
+                          recreate the links to point to the just installed
+                          version of libpng. The default is to create the
+                          links; use --disable-unversioned-links to change
+                          this
+  --enable-unversioned-libpng-pc
+                          Install the configuration file 'libpng.pc' as a link
+                          to the versioned version. This is done by default -
+                          use --disable-unversioned-libpng-pc to change this.
+  --enable-unversioned-libpng-config
+                          Install the configuration file 'libpng-config' as a
+                          link to the versioned version. This is done by
+                          default - use --disable-unversioned-libpng-config to
+                          change this.
+  --enable-hardware-optimizations
+                          Enable hardware optimizations: =no/off, yes/on.
+  --enable-arm-neon     Enable ARM NEON optimizations: =no/off, check, api,
+                          yes/on. no/off: disable the optimizations; check:
+                          use internal checking code (deprecated and poorly
+                          supported); api: disable by default, enable by a
+                          call to png_set_option; yes/on: turn on
+                          unconditionally. If not specified: determined by the
+                          compiler.
+  --enable-mips-msa     Enable MIPS MSA optimizations: =no/off, check, api,
+                          yes/on. no/off: disable the optimizations; check:
+                          use internal checking code (deprecated and poorly
+                          supported); api: disable by default, enable by a
+                          call to png_set_option; yes/on: turn on
+                          unconditionally. If not specified: determined by the
+                          compiler.
+  --enable-mips-mmi     Enable MIPS MMI optimizations: =no/off, check, api,
+                          yes/on. no/off: disable the optimizations; check:
+                          use internal checking code (deprecated and poorly
+                          supported); api: disable by default, enable by a
+                          call to png_set_option; yes/on: turn on
+                          unconditionally. If not specified: determined by the
+                          compiler.
+  --enable-intel-sse    Enable Intel SSE optimizations: =no/off, yes/on.
+                          no/off: disable the optimizations; yes/on: enable
+                          the optimizations. If not specified: determined by
+                          the compiler.
+  --enable-powerpc-vsx  Enable POWERPC VSX optimizations: =no/off, check,
+                          api, yes/on. no/off: disable the optimizations;
+                          check: use internal checking code; api: disable by
+                          default, enable by a call to png_set_option; yes/on:
+                          turn on unconditionally. If not specified:
+                          determined by the compiler.
+  --enable-loongarch-lsx
+                          Enable LOONGARCH LSX optimizations: =no/off, yes/on:
+                          no/off: disable the optimizations; yes/on: turn on
+                          unconditionally. If not specified: determined by the
+                          compiler.
+
+Optional Packages:
+  --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
+  --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
+  --with-gnu-ld           assume the C compiler uses GNU ld [default=no]
+  --with-pic[=PKGS]       try to use only PIC/non-PIC objects [default=use
+                          both]
+  --with-aix-soname=aix|svr4|both
+                          shared library versioning (aka "SONAME") variant to
+                          provide on AIX, [default=aix].
+  --with-sysroot[=DIR]    Search for dependent libraries within DIR (or the
+                          compiler's sysroot if not specified).
+  --with-zlib-prefix    prefix that may have been used in installed zlib
+  --with-pkgconfigdir   Use the specified pkgconfig dir (default is
+                          libdir/pkgconfig)
+  --with-binconfigs     Generate shell libpng-config scripts as well as
+                          pkg-config data [default=yes]
+  --with-libpng-prefix  prefix libpng exported function (API) names with the
+                          given value
+
+Some influential environment variables:
+  CC          C compiler command
+  CFLAGS      C compiler flags
+  LDFLAGS     linker flags, e.g. -L<lib dir> if you have libraries in a
+              nonstandard directory <lib dir>
+  LIBS        libraries to pass to the linker, e.g. -l<library>
+  CPPFLAGS    (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
+              you have headers in a nonstandard directory <include dir>
+  CCAS        assembler compiler command (defaults to CC)
+  CCASFLAGS   assembler compiler flags (defaults to CFLAGS)
+  CPP         C preprocessor
+  LT_SYS_LIBRARY_PATH
+              User-defined run-time library search path.
+  AWK         AWK language processor
+  PNG_COPTS   additional flags for the C compiler, to be used for options that
+              would cause configure itself to fail
+
+Use these variables to override the choices made by 'configure' or to help
+it to find libraries and programs with nonstandard names/locations.
+
+Report bugs to <png-mng-implement@lists.sourceforge.net>.
+_ACEOF
+ac_status=$?
+fi
+
+if test "$ac_init_help" = "recursive"; then
+  # If there are subdirs, report their specific --help.
+  for ac_dir in : $ac_subdirs_all; do test "x$ac_dir" = x: && continue
+    test -d "$ac_dir" ||
+      { cd "$srcdir" && ac_pwd=`pwd` && srcdir=. && test -d "$ac_dir"; } ||
+      continue
+    ac_builddir=.
+
+case "$ac_dir" in
+.) ac_dir_suffix= ac_top_builddir_sub=. ac_top_build_prefix= ;;
+*)
+  ac_dir_suffix=/`printf "%s\n" "$ac_dir" | sed 's|^\.[\\/]||'`
+  # A ".." for each directory in $ac_dir_suffix.
+  ac_top_builddir_sub=`printf "%s\n" "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
+  case $ac_top_builddir_sub in
+  "") ac_top_builddir_sub=. ac_top_build_prefix= ;;
+  *)  ac_top_build_prefix=$ac_top_builddir_sub/ ;;
+  esac ;;
+esac
+ac_abs_top_builddir=$ac_pwd
+ac_abs_builddir=$ac_pwd$ac_dir_suffix
+# for backward compatibility:
+ac_top_builddir=$ac_top_build_prefix
+
+case $srcdir in
+  .)  # We are building in place.
+    ac_srcdir=.
+    ac_top_srcdir=$ac_top_builddir_sub
+    ac_abs_top_srcdir=$ac_pwd ;;
+  [\\/]* | ?:[\\/]* )  # Absolute name.
+    ac_srcdir=$srcdir$ac_dir_suffix;
+    ac_top_srcdir=$srcdir
+    ac_abs_top_srcdir=$srcdir ;;
+  *) # Relative name.
+    ac_srcdir=$ac_top_build_prefix$srcdir$ac_dir_suffix
+    ac_top_srcdir=$ac_top_build_prefix$srcdir
+    ac_abs_top_srcdir=$ac_pwd/$srcdir ;;
+esac
+ac_abs_srcdir=$ac_abs_top_srcdir$ac_dir_suffix
+
+    cd "$ac_dir" || { ac_status=$?; continue; }
+    # Check for configure.gnu first; this name is used for a wrapper for
+    # Metaconfig's "Configure" on case-insensitive file systems.
+    if test -f "$ac_srcdir/configure.gnu"; then
+      echo &&
+      $SHELL "$ac_srcdir/configure.gnu" --help=recursive
+    elif test -f "$ac_srcdir/configure"; then
+      echo &&
+      $SHELL "$ac_srcdir/configure" --help=recursive
+    else
+      printf "%s\n" "$as_me: WARNING: no configuration information is in $ac_dir" >&2
+    fi || ac_status=$?
+    cd "$ac_pwd" || { ac_status=$?; break; }
+  done
+fi
+
+test -n "$ac_init_help" && exit $ac_status
+if $ac_init_version; then
+  cat <<\_ACEOF
+libpng configure 1.6.43
+generated by GNU Autoconf 2.72
+
+Copyright (C) 2023 Free Software Foundation, Inc.
+This configure script is free software; the Free Software Foundation
+gives unlimited permission to copy, distribute and modify it.
+_ACEOF
+  exit
+fi
+
+## ------------------------ ##
+## Autoconf initialization. ##
+## ------------------------ ##
+
+# ac_fn_c_try_compile LINENO
+# --------------------------
+# Try to compile conftest.$ac_ext, and return whether this succeeded.
+ac_fn_c_try_compile ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  rm -f conftest.$ac_objext conftest.beam
+  if { { ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_compile") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    grep -v '^ *+' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+    mv -f conftest.er1 conftest.err
+  fi
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest.$ac_objext
+then :
+  ac_retval=0
+else case e in #(
+  e) printf "%s\n" "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_retval=1 ;;
+esac
+fi
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_compile
+
+# ac_fn_c_try_cpp LINENO
+# ----------------------
+# Try to preprocess conftest.$ac_ext, and return whether this succeeded.
+ac_fn_c_try_cpp ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  if { { ac_try="$ac_cpp conftest.$ac_ext"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_cpp conftest.$ac_ext") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    grep -v '^ *+' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+    mv -f conftest.er1 conftest.err
+  fi
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } > conftest.i && {
+	 test -z "$ac_c_preproc_warn_flag$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       }
+then :
+  ac_retval=0
+else case e in #(
+  e) printf "%s\n" "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+    ac_retval=1 ;;
+esac
+fi
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_cpp
+
+# ac_fn_c_try_link LINENO
+# -----------------------
+# Try to link conftest.$ac_ext, and return whether this succeeded.
+ac_fn_c_try_link ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  rm -f conftest.$ac_objext conftest.beam conftest$ac_exeext
+  if { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    grep -v '^ *+' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+    mv -f conftest.er1 conftest.err
+  fi
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext && {
+	 test "$cross_compiling" = yes ||
+	 test -x conftest$ac_exeext
+       }
+then :
+  ac_retval=0
+else case e in #(
+  e) printf "%s\n" "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_retval=1 ;;
+esac
+fi
+  # Delete the IPA/IPO (Inter Procedural Analysis/Optimization) information
+  # created by the PGI compiler (conftest_ipa8_conftest.oo), as it would
+  # interfere with the next link command; also delete a directory that is
+  # left behind by Apple's compiler.  We do this before executing the actions.
+  rm -rf conftest.dSYM conftest_ipa8_conftest.oo
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_link
+
+# ac_fn_c_check_header_compile LINENO HEADER VAR INCLUDES
+# -------------------------------------------------------
+# Tests whether HEADER exists and can be compiled using the include files in
+# INCLUDES, setting the cache variable VAR accordingly.
+ac_fn_c_check_header_compile ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
+printf %s "checking for $2... " >&6; }
+if eval test \${$3+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$4
+#include <$2>
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  eval "$3=yes"
+else case e in #(
+  e) eval "$3=no" ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext ;;
+esac
+fi
+eval ac_res=\$$3
+	       { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+printf "%s\n" "$ac_res" >&6; }
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_c_check_header_compile
+
+# ac_fn_c_check_func LINENO FUNC VAR
+# ----------------------------------
+# Tests whether FUNC exists, setting the cache variable VAR accordingly
+ac_fn_c_check_func ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
+printf %s "checking for $2... " >&6; }
+if eval test \${$3+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+/* Define $2 to an innocuous variant, in case <limits.h> declares $2.
+   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
+#define $2 innocuous_$2
+
+/* System header to define __stub macros and hopefully few prototypes,
+   which can conflict with char $2 (void); below.  */
+
+#include <limits.h>
+#undef $2
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char $2 (void);
+/* The GNU C library defines this for functions which it implements
+    to always fail with ENOSYS.  Some functions are actually named
+    something starting with __ and the normal name is an alias.  */
+#if defined __stub_$2 || defined __stub___$2
+choke me
+#endif
+
+int
+main (void)
+{
+return $2 ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  eval "$3=yes"
+else case e in #(
+  e) eval "$3=no" ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext ;;
+esac
+fi
+eval ac_res=\$$3
+	       { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+printf "%s\n" "$ac_res" >&6; }
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_c_check_func
+ac_configure_args_raw=
+for ac_arg
+do
+  case $ac_arg in
+  *\'*)
+    ac_arg=`printf "%s\n" "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
+  esac
+  as_fn_append ac_configure_args_raw " '$ac_arg'"
+done
+
+case $ac_configure_args_raw in
+  *$as_nl*)
+    ac_safe_unquote= ;;
+  *)
+    ac_unsafe_z='|&;<>()$`\\"*?[ ''	' # This string ends in space, tab.
+    ac_unsafe_a="$ac_unsafe_z#~"
+    ac_safe_unquote="s/ '\\([^$ac_unsafe_a][^$ac_unsafe_z]*\\)'/ \\1/g"
+    ac_configure_args_raw=`      printf "%s\n" "$ac_configure_args_raw" | sed "$ac_safe_unquote"`;;
+esac
+
+cat >config.log <<_ACEOF
+This file contains any messages produced by compilers while
+running configure, to aid debugging if configure makes a mistake.
+
+It was created by libpng $as_me 1.6.43, which was
+generated by GNU Autoconf 2.72.  Invocation command line was
+
+  $ $0$ac_configure_args_raw
+
+_ACEOF
+exec 5>>config.log
+{
+cat <<_ASUNAME
+## --------- ##
+## Platform. ##
+## --------- ##
+
+hostname = `(hostname || uname -n) 2>/dev/null | sed 1q`
+uname -m = `(uname -m) 2>/dev/null || echo unknown`
+uname -r = `(uname -r) 2>/dev/null || echo unknown`
+uname -s = `(uname -s) 2>/dev/null || echo unknown`
+uname -v = `(uname -v) 2>/dev/null || echo unknown`
+
+/usr/bin/uname -p = `(/usr/bin/uname -p) 2>/dev/null || echo unknown`
+/bin/uname -X     = `(/bin/uname -X) 2>/dev/null     || echo unknown`
+
+/bin/arch              = `(/bin/arch) 2>/dev/null              || echo unknown`
+/usr/bin/arch -k       = `(/usr/bin/arch -k) 2>/dev/null       || echo unknown`
+/usr/convex/getsysinfo = `(/usr/convex/getsysinfo) 2>/dev/null || echo unknown`
+/usr/bin/hostinfo      = `(/usr/bin/hostinfo) 2>/dev/null      || echo unknown`
+/bin/machine           = `(/bin/machine) 2>/dev/null           || echo unknown`
+/usr/bin/oslevel       = `(/usr/bin/oslevel) 2>/dev/null       || echo unknown`
+/bin/universe          = `(/bin/universe) 2>/dev/null          || echo unknown`
+
+_ASUNAME
+
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    printf "%s\n" "PATH: $as_dir"
+  done
+IFS=$as_save_IFS
+
+} >&5
+
+cat >&5 <<_ACEOF
+
+
+## ----------- ##
+## Core tests. ##
+## ----------- ##
+
+_ACEOF
+
+
+# Keep a trace of the command line.
+# Strip out --no-create and --no-recursion so they do not pile up.
+# Strip out --silent because we don't want to record it for future runs.
+# Also quote any args containing shell meta-characters.
+# Make two passes to allow for proper duplicate-argument suppression.
+ac_configure_args=
+ac_configure_args0=
+ac_configure_args1=
+ac_must_keep_next=false
+for ac_pass in 1 2
+do
+  for ac_arg
+  do
+    case $ac_arg in
+    -no-create | --no-c* | -n | -no-recursion | --no-r*) continue ;;
+    -q | -quiet | --quiet | --quie | --qui | --qu | --q \
+    | -silent | --silent | --silen | --sile | --sil)
+      continue ;;
+    *\'*)
+      ac_arg=`printf "%s\n" "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    esac
+    case $ac_pass in
+    1) as_fn_append ac_configure_args0 " '$ac_arg'" ;;
+    2)
+      as_fn_append ac_configure_args1 " '$ac_arg'"
+      if test $ac_must_keep_next = true; then
+	ac_must_keep_next=false # Got value, back to normal.
+      else
+	case $ac_arg in
+	  *=* | --config-cache | -C | -disable-* | --disable-* \
+	  | -enable-* | --enable-* | -gas | --g* | -nfp | --nf* \
+	  | -q | -quiet | --q* | -silent | --sil* | -v | -verb* \
+	  | -with-* | --with-* | -without-* | --without-* | --x)
+	    case "$ac_configure_args0 " in
+	      "$ac_configure_args1"*" '$ac_arg' "* ) continue ;;
+	    esac
+	    ;;
+	  -* ) ac_must_keep_next=true ;;
+	esac
+      fi
+      as_fn_append ac_configure_args " '$ac_arg'"
+      ;;
+    esac
+  done
+done
+{ ac_configure_args0=; unset ac_configure_args0;}
+{ ac_configure_args1=; unset ac_configure_args1;}
+
+# When interrupted or exit'd, cleanup temporary files, and complete
+# config.log.  We remove comments because anyway the quotes in there
+# would cause problems or look ugly.
+# WARNING: Use '\'' to represent an apostrophe within the trap.
+# WARNING: Do not start the trap code with a newline, due to a FreeBSD 4.0 bug.
+trap 'exit_status=$?
+  # Sanitize IFS.
+  IFS=" ""	$as_nl"
+  # Save into config.log some information that might help in debugging.
+  {
+    echo
+
+    printf "%s\n" "## ---------------- ##
+## Cache variables. ##
+## ---------------- ##"
+    echo
+    # The following way of writing the cache mishandles newlines in values,
+(
+  for ac_var in `(set) 2>&1 | sed -n '\''s/^\([a-zA-Z_][a-zA-Z0-9_]*\)=.*/\1/p'\''`; do
+    eval ac_val=\$$ac_var
+    case $ac_val in #(
+    *${as_nl}*)
+      case $ac_var in #(
+      *_cv_*) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
+printf "%s\n" "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
+      esac
+      case $ac_var in #(
+      _ | IFS | as_nl) ;; #(
+      BASH_ARGV | BASH_SOURCE) eval $ac_var= ;; #(
+      *) { eval $ac_var=; unset $ac_var;} ;;
+      esac ;;
+    esac
+  done
+  (set) 2>&1 |
+    case $as_nl`(ac_space='\'' '\''; set) 2>&1` in #(
+    *${as_nl}ac_space=\ *)
+      sed -n \
+	"s/'\''/'\''\\\\'\'''\''/g;
+	  s/^\\([_$as_cr_alnum]*_cv_[_$as_cr_alnum]*\\)=\\(.*\\)/\\1='\''\\2'\''/p"
+      ;; #(
+    *)
+      sed -n "/^[_$as_cr_alnum]*_cv_[_$as_cr_alnum]*=/p"
+      ;;
+    esac |
+    sort
+)
+    echo
+
+    printf "%s\n" "## ----------------- ##
+## Output variables. ##
+## ----------------- ##"
+    echo
+    for ac_var in $ac_subst_vars
+    do
+      eval ac_val=\$$ac_var
+      case $ac_val in
+      *\'\''*) ac_val=`printf "%s\n" "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
+      esac
+      printf "%s\n" "$ac_var='\''$ac_val'\''"
+    done | sort
+    echo
+
+    if test -n "$ac_subst_files"; then
+      printf "%s\n" "## ------------------- ##
+## File substitutions. ##
+## ------------------- ##"
+      echo
+      for ac_var in $ac_subst_files
+      do
+	eval ac_val=\$$ac_var
+	case $ac_val in
+	*\'\''*) ac_val=`printf "%s\n" "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
+	esac
+	printf "%s\n" "$ac_var='\''$ac_val'\''"
+      done | sort
+      echo
+    fi
+
+    if test -s confdefs.h; then
+      printf "%s\n" "## ----------- ##
+## confdefs.h. ##
+## ----------- ##"
+      echo
+      cat confdefs.h
+      echo
+    fi
+    test "$ac_signal" != 0 &&
+      printf "%s\n" "$as_me: caught signal $ac_signal"
+    printf "%s\n" "$as_me: exit $exit_status"
+  } >&5
+  rm -f core *.core core.conftest.* &&
+    rm -f -r conftest* confdefs* conf$$* $ac_clean_files &&
+    exit $exit_status
+' 0
+for ac_signal in 1 2 13 15; do
+  trap 'ac_signal='$ac_signal'; as_fn_exit 1' $ac_signal
+done
+ac_signal=0
+
+# confdefs.h avoids OS command line length limits that DEFS can exceed.
+rm -f -r conftest* confdefs.h
+
+printf "%s\n" "/* confdefs.h */" > confdefs.h
+
+# Predefined preprocessor variables.
+
+printf "%s\n" "#define PACKAGE_NAME \"$PACKAGE_NAME\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_TARNAME \"$PACKAGE_TARNAME\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_VERSION \"$PACKAGE_VERSION\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_STRING \"$PACKAGE_STRING\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_BUGREPORT \"$PACKAGE_BUGREPORT\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_URL \"$PACKAGE_URL\"" >>confdefs.h
+
+
+# Let the site file select an alternate cache file if it wants to.
+# Prefer an explicitly selected file to automatically selected ones.
+if test -n "$CONFIG_SITE"; then
+  ac_site_files="$CONFIG_SITE"
+elif test "x$prefix" != xNONE; then
+  ac_site_files="$prefix/share/config.site $prefix/etc/config.site"
+else
+  ac_site_files="$ac_default_prefix/share/config.site $ac_default_prefix/etc/config.site"
+fi
+
+for ac_site_file in $ac_site_files
+do
+  case $ac_site_file in #(
+  */*) :
+     ;; #(
+  *) :
+    ac_site_file=./$ac_site_file ;;
+esac
+  if test -f "$ac_site_file" && test -r "$ac_site_file"; then
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: loading site script $ac_site_file" >&5
+printf "%s\n" "$as_me: loading site script $ac_site_file" >&6;}
+    sed 's/^/| /' "$ac_site_file" >&5
+    . "$ac_site_file" \
+      || { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+as_fn_error $? "failed to load site script $ac_site_file
+See 'config.log' for more details" "$LINENO" 5; }
+  fi
+done
+
+if test -r "$cache_file"; then
+  # Some versions of bash will fail to source /dev/null (special files
+  # actually), so we avoid doing that.  DJGPP emulates it as a regular file.
+  if test /dev/null != "$cache_file" && test -f "$cache_file"; then
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: loading cache $cache_file" >&5
+printf "%s\n" "$as_me: loading cache $cache_file" >&6;}
+    case $cache_file in
+      [\\/]* | ?:[\\/]* ) . "$cache_file";;
+      *)                      . "./$cache_file";;
+    esac
+  fi
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: creating cache $cache_file" >&5
+printf "%s\n" "$as_me: creating cache $cache_file" >&6;}
+  >$cache_file
+fi
+
+# Test code for whether the C compiler supports C89 (global declarations)
+ac_c_conftest_c89_globals='
+/* Does the compiler advertise C89 conformance?
+   Do not test the value of __STDC__, because some compilers set it to 0
+   while being otherwise adequately conformant. */
+#if !defined __STDC__
+# error "Compiler does not advertise C89 conformance"
+#endif
+
+#include <stddef.h>
+#include <stdarg.h>
+struct stat;
+/* Most of the following tests are stolen from RCS 5.7 src/conf.sh.  */
+struct buf { int x; };
+struct buf * (*rcsopen) (struct buf *, struct stat *, int);
+static char *e (char **p, int i)
+{
+  return p[i];
+}
+static char *f (char * (*g) (char **, int), char **p, ...)
+{
+  char *s;
+  va_list v;
+  va_start (v,p);
+  s = g (p, va_arg (v,int));
+  va_end (v);
+  return s;
+}
+
+/* C89 style stringification. */
+#define noexpand_stringify(a) #a
+const char *stringified = noexpand_stringify(arbitrary+token=sequence);
+
+/* C89 style token pasting.  Exercises some of the corner cases that
+   e.g. old MSVC gets wrong, but not very hard. */
+#define noexpand_concat(a,b) a##b
+#define expand_concat(a,b) noexpand_concat(a,b)
+extern int vA;
+extern int vbee;
+#define aye A
+#define bee B
+int *pvA = &expand_concat(v,aye);
+int *pvbee = &noexpand_concat(v,bee);
+
+/* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
+   function prototypes and stuff, but not \xHH hex character constants.
+   These do not provoke an error unfortunately, instead are silently treated
+   as an "x".  The following induces an error, until -std is added to get
+   proper ANSI mode.  Curiously \x00 != x always comes out true, for an
+   array size at least.  It is necessary to write \x00 == 0 to get something
+   that is true only with -std.  */
+int osf4_cc_array ['\''\x00'\'' == 0 ? 1 : -1];
+
+/* IBM C 6 for AIX is almost-ANSI by default, but it replaces macro parameters
+   inside strings and character constants.  */
+#define FOO(x) '\''x'\''
+int xlc6_cc_array[FOO(a) == '\''x'\'' ? 1 : -1];
+
+int test (int i, double x);
+struct s1 {int (*f) (int a);};
+struct s2 {int (*f) (double a);};
+int pairnames (int, char **, int *(*)(struct buf *, struct stat *, int),
+               int, int);'
+
+# Test code for whether the C compiler supports C89 (body of main).
+ac_c_conftest_c89_main='
+ok |= (argc == 0 || f (e, argv, 0) != argv[0] || f (e, argv, 1) != argv[1]);
+'
+
+# Test code for whether the C compiler supports C99 (global declarations)
+ac_c_conftest_c99_globals='
+/* Does the compiler advertise C99 conformance? */
+#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 199901L
+# error "Compiler does not advertise C99 conformance"
+#endif
+
+// See if C++-style comments work.
+
+#include <stdbool.h>
+extern int puts (const char *);
+extern int printf (const char *, ...);
+extern int dprintf (int, const char *, ...);
+extern void *malloc (size_t);
+extern void free (void *);
+
+// Check varargs macros.  These examples are taken from C99 6.10.3.5.
+// dprintf is used instead of fprintf to avoid needing to declare
+// FILE and stderr.
+#define debug(...) dprintf (2, __VA_ARGS__)
+#define showlist(...) puts (#__VA_ARGS__)
+#define report(test,...) ((test) ? puts (#test) : printf (__VA_ARGS__))
+static void
+test_varargs_macros (void)
+{
+  int x = 1234;
+  int y = 5678;
+  debug ("Flag");
+  debug ("X = %d\n", x);
+  showlist (The first, second, and third items.);
+  report (x>y, "x is %d but y is %d", x, y);
+}
+
+// Check long long types.
+#define BIG64 18446744073709551615ull
+#define BIG32 4294967295ul
+#define BIG_OK (BIG64 / BIG32 == 4294967297ull && BIG64 % BIG32 == 0)
+#if !BIG_OK
+  #error "your preprocessor is broken"
+#endif
+#if BIG_OK
+#else
+  #error "your preprocessor is broken"
+#endif
+static long long int bignum = -9223372036854775807LL;
+static unsigned long long int ubignum = BIG64;
+
+struct incomplete_array
+{
+  int datasize;
+  double data[];
+};
+
+struct named_init {
+  int number;
+  const wchar_t *name;
+  double average;
+};
+
+typedef const char *ccp;
+
+static inline int
+test_restrict (ccp restrict text)
+{
+  // Iterate through items via the restricted pointer.
+  // Also check for declarations in for loops.
+  for (unsigned int i = 0; *(text+i) != '\''\0'\''; ++i)
+    continue;
+  return 0;
+}
+
+// Check varargs and va_copy.
+static bool
+test_varargs (const char *format, ...)
+{
+  va_list args;
+  va_start (args, format);
+  va_list args_copy;
+  va_copy (args_copy, args);
+
+  const char *str = "";
+  int number = 0;
+  float fnumber = 0;
+
+  while (*format)
+    {
+      switch (*format++)
+	{
+	case '\''s'\'': // string
+	  str = va_arg (args_copy, const char *);
+	  break;
+	case '\''d'\'': // int
+	  number = va_arg (args_copy, int);
+	  break;
+	case '\''f'\'': // float
+	  fnumber = va_arg (args_copy, double);
+	  break;
+	default:
+	  break;
+	}
+    }
+  va_end (args_copy);
+  va_end (args);
+
+  return *str && number && fnumber;
+}
+'
+
+# Test code for whether the C compiler supports C99 (body of main).
+ac_c_conftest_c99_main='
+  // Check bool.
+  _Bool success = false;
+  success |= (argc != 0);
+
+  // Check restrict.
+  if (test_restrict ("String literal") == 0)
+    success = true;
+  char *restrict newvar = "Another string";
+
+  // Check varargs.
+  success &= test_varargs ("s, d'\'' f .", "string", 65, 34.234);
+  test_varargs_macros ();
+
+  // Check flexible array members.
+  struct incomplete_array *ia =
+    malloc (sizeof (struct incomplete_array) + (sizeof (double) * 10));
+  ia->datasize = 10;
+  for (int i = 0; i < ia->datasize; ++i)
+    ia->data[i] = i * 1.234;
+  // Work around memory leak warnings.
+  free (ia);
+
+  // Check named initializers.
+  struct named_init ni = {
+    .number = 34,
+    .name = L"Test wide string",
+    .average = 543.34343,
+  };
+
+  ni.number = 58;
+
+  int dynamic_array[ni.number];
+  dynamic_array[0] = argv[0][0];
+  dynamic_array[ni.number - 1] = 543;
+
+  // work around unused variable warnings
+  ok |= (!success || bignum == 0LL || ubignum == 0uLL || newvar[0] == '\''x'\''
+	 || dynamic_array[ni.number - 1] != 543);
+'
+
+# Test code for whether the C compiler supports C11 (global declarations)
+ac_c_conftest_c11_globals='
+/* Does the compiler advertise C11 conformance? */
+#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112L
+# error "Compiler does not advertise C11 conformance"
+#endif
+
+// Check _Alignas.
+char _Alignas (double) aligned_as_double;
+char _Alignas (0) no_special_alignment;
+extern char aligned_as_int;
+char _Alignas (0) _Alignas (int) aligned_as_int;
+
+// Check _Alignof.
+enum
+{
+  int_alignment = _Alignof (int),
+  int_array_alignment = _Alignof (int[100]),
+  char_alignment = _Alignof (char)
+};
+_Static_assert (0 < -_Alignof (int), "_Alignof is signed");
+
+// Check _Noreturn.
+int _Noreturn does_not_return (void) { for (;;) continue; }
+
+// Check _Static_assert.
+struct test_static_assert
+{
+  int x;
+  _Static_assert (sizeof (int) <= sizeof (long int),
+                  "_Static_assert does not work in struct");
+  long int y;
+};
+
+// Check UTF-8 literals.
+#define u8 syntax error!
+char const utf8_literal[] = u8"happens to be ASCII" "another string";
+
+// Check duplicate typedefs.
+typedef long *long_ptr;
+typedef long int *long_ptr;
+typedef long_ptr long_ptr;
+
+// Anonymous structures and unions -- taken from C11 6.7.2.1 Example 1.
+struct anonymous
+{
+  union {
+    struct { int i; int j; };
+    struct { int k; long int l; } w;
+  };
+  int m;
+} v1;
+'
+
+# Test code for whether the C compiler supports C11 (body of main).
+ac_c_conftest_c11_main='
+  _Static_assert ((offsetof (struct anonymous, i)
+		   == offsetof (struct anonymous, w.k)),
+		  "Anonymous union alignment botch");
+  v1.i = 2;
+  v1.w.k = 5;
+  ok |= v1.i != 5;
+'
+
+# Test code for whether the C compiler supports C11 (complete).
+ac_c_conftest_c11_program="${ac_c_conftest_c89_globals}
+${ac_c_conftest_c99_globals}
+${ac_c_conftest_c11_globals}
+
+int
+main (int argc, char **argv)
+{
+  int ok = 0;
+  ${ac_c_conftest_c89_main}
+  ${ac_c_conftest_c99_main}
+  ${ac_c_conftest_c11_main}
+  return ok;
+}
+"
+
+# Test code for whether the C compiler supports C99 (complete).
+ac_c_conftest_c99_program="${ac_c_conftest_c89_globals}
+${ac_c_conftest_c99_globals}
+
+int
+main (int argc, char **argv)
+{
+  int ok = 0;
+  ${ac_c_conftest_c89_main}
+  ${ac_c_conftest_c99_main}
+  return ok;
+}
+"
+
+# Test code for whether the C compiler supports C89 (complete).
+ac_c_conftest_c89_program="${ac_c_conftest_c89_globals}
+
+int
+main (int argc, char **argv)
+{
+  int ok = 0;
+  ${ac_c_conftest_c89_main}
+  return ok;
+}
+"
+
+as_fn_append ac_header_c_list " stdio.h stdio_h HAVE_STDIO_H"
+as_fn_append ac_header_c_list " stdlib.h stdlib_h HAVE_STDLIB_H"
+as_fn_append ac_header_c_list " string.h string_h HAVE_STRING_H"
+as_fn_append ac_header_c_list " inttypes.h inttypes_h HAVE_INTTYPES_H"
+as_fn_append ac_header_c_list " stdint.h stdint_h HAVE_STDINT_H"
+as_fn_append ac_header_c_list " strings.h strings_h HAVE_STRINGS_H"
+as_fn_append ac_header_c_list " sys/stat.h sys_stat_h HAVE_SYS_STAT_H"
+as_fn_append ac_header_c_list " sys/types.h sys_types_h HAVE_SYS_TYPES_H"
+as_fn_append ac_header_c_list " unistd.h unistd_h HAVE_UNISTD_H"
+
+# Auxiliary files required by this configure script.
+ac_aux_files="ltmain.sh config.guess config.sub compile missing install-sh"
+
+# Locations in which to look for auxiliary files.
+ac_aux_dir_candidates="${srcdir}${PATH_SEPARATOR}${srcdir}/..${PATH_SEPARATOR}${srcdir}/../.."
+
+# Search for a directory containing all of the required auxiliary files,
+# $ac_aux_files, from the $PATH-style list $ac_aux_dir_candidates.
+# If we don't find one directory that contains all the files we need,
+# we report the set of missing files from the *first* directory in
+# $ac_aux_dir_candidates and give up.
+ac_missing_aux_files=""
+ac_first_candidate=:
+printf "%s\n" "$as_me:${as_lineno-$LINENO}: looking for aux files: $ac_aux_files" >&5
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+as_found=false
+for as_dir in $ac_aux_dir_candidates
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+  as_found=:
+
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}:  trying $as_dir" >&5
+  ac_aux_dir_found=yes
+  ac_install_sh=
+  for ac_aux in $ac_aux_files
+  do
+    # As a special case, if "install-sh" is required, that requirement
+    # can be satisfied by any of "install-sh", "install.sh", or "shtool",
+    # and $ac_install_sh is set appropriately for whichever one is found.
+    if test x"$ac_aux" = x"install-sh"
+    then
+      if test -f "${as_dir}install-sh"; then
+        printf "%s\n" "$as_me:${as_lineno-$LINENO}:   ${as_dir}install-sh found" >&5
+        ac_install_sh="${as_dir}install-sh -c"
+      elif test -f "${as_dir}install.sh"; then
+        printf "%s\n" "$as_me:${as_lineno-$LINENO}:   ${as_dir}install.sh found" >&5
+        ac_install_sh="${as_dir}install.sh -c"
+      elif test -f "${as_dir}shtool"; then
+        printf "%s\n" "$as_me:${as_lineno-$LINENO}:   ${as_dir}shtool found" >&5
+        ac_install_sh="${as_dir}shtool install -c"
+      else
+        ac_aux_dir_found=no
+        if $ac_first_candidate; then
+          ac_missing_aux_files="${ac_missing_aux_files} install-sh"
+        else
+          break
+        fi
+      fi
+    else
+      if test -f "${as_dir}${ac_aux}"; then
+        printf "%s\n" "$as_me:${as_lineno-$LINENO}:   ${as_dir}${ac_aux} found" >&5
+      else
+        ac_aux_dir_found=no
+        if $ac_first_candidate; then
+          ac_missing_aux_files="${ac_missing_aux_files} ${ac_aux}"
+        else
+          break
+        fi
+      fi
+    fi
+  done
+  if test "$ac_aux_dir_found" = yes; then
+    ac_aux_dir="$as_dir"
+    break
+  fi
+  ac_first_candidate=false
+
+  as_found=false
+done
+IFS=$as_save_IFS
+if $as_found
+then :
+
+else case e in #(
+  e) as_fn_error $? "cannot find required auxiliary files:$ac_missing_aux_files" "$LINENO" 5 ;;
+esac
+fi
+
+
+# These three variables are undocumented and unsupported,
+# and are intended to be withdrawn in a future Autoconf release.
+# They can cause serious problems if a builder's source tree is in a directory
+# whose full name contains unusual characters.
+if test -f "${ac_aux_dir}config.guess"; then
+  ac_config_guess="$SHELL ${ac_aux_dir}config.guess"
+fi
+if test -f "${ac_aux_dir}config.sub"; then
+  ac_config_sub="$SHELL ${ac_aux_dir}config.sub"
+fi
+if test -f "$ac_aux_dir/configure"; then
+  ac_configure="$SHELL ${ac_aux_dir}configure"
+fi
+
+# Check that the precious variables saved in the cache have kept the same
+# value.
+ac_cache_corrupted=false
+for ac_var in $ac_precious_vars; do
+  eval ac_old_set=\$ac_cv_env_${ac_var}_set
+  eval ac_new_set=\$ac_env_${ac_var}_set
+  eval ac_old_val=\$ac_cv_env_${ac_var}_value
+  eval ac_new_val=\$ac_env_${ac_var}_value
+  case $ac_old_set,$ac_new_set in
+    set,)
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: '$ac_var' was set to '$ac_old_val' in the previous run" >&5
+printf "%s\n" "$as_me: error: '$ac_var' was set to '$ac_old_val' in the previous run" >&2;}
+      ac_cache_corrupted=: ;;
+    ,set)
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: '$ac_var' was not set in the previous run" >&5
+printf "%s\n" "$as_me: error: '$ac_var' was not set in the previous run" >&2;}
+      ac_cache_corrupted=: ;;
+    ,);;
+    *)
+      if test "x$ac_old_val" != "x$ac_new_val"; then
+	# differences in whitespace do not lead to failure.
+	ac_old_val_w=`echo x $ac_old_val`
+	ac_new_val_w=`echo x $ac_new_val`
+	if test "$ac_old_val_w" != "$ac_new_val_w"; then
+	  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: '$ac_var' has changed since the previous run:" >&5
+printf "%s\n" "$as_me: error: '$ac_var' has changed since the previous run:" >&2;}
+	  ac_cache_corrupted=:
+	else
+	  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: warning: ignoring whitespace changes in '$ac_var' since the previous run:" >&5
+printf "%s\n" "$as_me: warning: ignoring whitespace changes in '$ac_var' since the previous run:" >&2;}
+	  eval $ac_var=\$ac_old_val
+	fi
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}:   former value:  '$ac_old_val'" >&5
+printf "%s\n" "$as_me:   former value:  '$ac_old_val'" >&2;}
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}:   current value: '$ac_new_val'" >&5
+printf "%s\n" "$as_me:   current value: '$ac_new_val'" >&2;}
+      fi;;
+  esac
+  # Pass precious variables to config.status.
+  if test "$ac_new_set" = set; then
+    case $ac_new_val in
+    *\'*) ac_arg=$ac_var=`printf "%s\n" "$ac_new_val" | sed "s/'/'\\\\\\\\''/g"` ;;
+    *) ac_arg=$ac_var=$ac_new_val ;;
+    esac
+    case " $ac_configure_args " in
+      *" '$ac_arg' "*) ;; # Avoid dups.  Use of quotes ensures accuracy.
+      *) as_fn_append ac_configure_args " '$ac_arg'" ;;
+    esac
+  fi
+done
+if $ac_cache_corrupted; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: changes in the environment can compromise the build" >&5
+printf "%s\n" "$as_me: error: changes in the environment can compromise the build" >&2;}
+  as_fn_error $? "run '${MAKE-make} distclean' and/or 'rm $cache_file'
+	    and start over" "$LINENO" 5
+fi
+## -------------------- ##
+## Main body of script. ##
+## -------------------- ##
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+
+
+# libpng does not follow GNU file name conventions (hence 'foreign')
+# color-tests requires automake 1.11 or later
+# silent-rules requires automake 1.11 or later
+# dist-xz requires automake 1.11 or later
+# 1.12.2 fixes a security issue in 1.11.2 and 1.12.1
+# 1.13 is required for parallel tests
+am__api_version='1.16'
+
+
+
+  # Find a good install program.  We prefer a C program (faster),
+# so one script is as good as another.  But avoid the broken or
+# incompatible versions:
+# SysV /etc/install, /usr/sbin/install
+# SunOS /usr/etc/install
+# IRIX /sbin/install
+# AIX /bin/install
+# AmigaOS /C/install, which installs bootblocks on floppy discs
+# AIX 4 /usr/bin/installbsd, which doesn't work without a -g flag
+# AFS /usr/afsws/bin/install, which mishandles nonexistent args
+# SVR4 /usr/ucb/install, which tries to use the nonexistent group "staff"
+# OS/2's system install, which has a completely different semantic
+# ./install, which can be erroneously created by make from ./install.sh.
+# Reject install programs that cannot install multiple files.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for a BSD-compatible install" >&5
+printf %s "checking for a BSD-compatible install... " >&6; }
+if test -z "$INSTALL"; then
+if test ${ac_cv_path_install+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    # Account for fact that we put trailing slashes in our PATH walk.
+case $as_dir in #((
+  ./ | /[cC]/* | \
+  /etc/* | /usr/sbin/* | /usr/etc/* | /sbin/* | /usr/afsws/bin/* | \
+  ?:[\\/]os2[\\/]install[\\/]* | ?:[\\/]OS2[\\/]INSTALL[\\/]* | \
+  /usr/ucb/* ) ;;
+  *)
+    # OSF1 and SCO ODT 3.0 have their own names for install.
+    # Don't use installbsd from OSF since it installs stuff as root
+    # by default.
+    for ac_prog in ginstall scoinst install; do
+      for ac_exec_ext in '' $ac_executable_extensions; do
+	if as_fn_executable_p "$as_dir$ac_prog$ac_exec_ext"; then
+	  if test $ac_prog = install &&
+	    grep dspmsg "$as_dir$ac_prog$ac_exec_ext" >/dev/null 2>&1; then
+	    # AIX install.  It has an incompatible calling convention.
+	    :
+	  elif test $ac_prog = install &&
+	    grep pwplus "$as_dir$ac_prog$ac_exec_ext" >/dev/null 2>&1; then
+	    # program-specific install script used by HP pwplus--don't use.
+	    :
+	  else
+	    rm -rf conftest.one conftest.two conftest.dir
+	    echo one > conftest.one
+	    echo two > conftest.two
+	    mkdir conftest.dir
+	    if "$as_dir$ac_prog$ac_exec_ext" -c conftest.one conftest.two "`pwd`/conftest.dir/" &&
+	      test -s conftest.one && test -s conftest.two &&
+	      test -s conftest.dir/conftest.one &&
+	      test -s conftest.dir/conftest.two
+	    then
+	      ac_cv_path_install="$as_dir$ac_prog$ac_exec_ext -c"
+	      break 3
+	    fi
+	  fi
+	fi
+      done
+    done
+    ;;
+esac
+
+  done
+IFS=$as_save_IFS
+
+rm -rf conftest.one conftest.two conftest.dir
+ ;;
+esac
+fi
+  if test ${ac_cv_path_install+y}; then
+    INSTALL=$ac_cv_path_install
+  else
+    # As a last resort, use the slow shell script.  Don't cache a
+    # value for INSTALL within a source directory, because that will
+    # break other packages using the cache if that directory is
+    # removed, or if the value is a relative name.
+    INSTALL=$ac_install_sh
+  fi
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $INSTALL" >&5
+printf "%s\n" "$INSTALL" >&6; }
+
+# Use test -z because SunOS4 sh mishandles braces in ${var-val}.
+# It thinks the first close brace ends the variable substitution.
+test -z "$INSTALL_PROGRAM" && INSTALL_PROGRAM='${INSTALL}'
+
+test -z "$INSTALL_SCRIPT" && INSTALL_SCRIPT='${INSTALL}'
+
+test -z "$INSTALL_DATA" && INSTALL_DATA='${INSTALL} -m 644'
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether build environment is sane" >&5
+printf %s "checking whether build environment is sane... " >&6; }
+# Reject unsafe characters in $srcdir or the absolute working directory
+# name.  Accept space and tab only in the latter.
+am_lf='
+'
+case `pwd` in
+  *[\\\"\#\$\&\'\`$am_lf]*)
+    as_fn_error $? "unsafe absolute working directory name" "$LINENO" 5;;
+esac
+case $srcdir in
+  *[\\\"\#\$\&\'\`$am_lf\ \	]*)
+    as_fn_error $? "unsafe srcdir value: '$srcdir'" "$LINENO" 5;;
+esac
+
+# Do 'set' in a subshell so we don't clobber the current shell's
+# arguments.  Must try -L first in case configure is actually a
+# symlink; some systems play weird games with the mod time of symlinks
+# (eg FreeBSD returns the mod time of the symlink's containing
+# directory).
+if (
+   am_has_slept=no
+   for am_try in 1 2; do
+     echo "timestamp, slept: $am_has_slept" > conftest.file
+     set X `ls -Lt "$srcdir/configure" conftest.file 2> /dev/null`
+     if test "$*" = "X"; then
+	# -L didn't work.
+	set X `ls -t "$srcdir/configure" conftest.file`
+     fi
+     if test "$*" != "X $srcdir/configure conftest.file" \
+	&& test "$*" != "X conftest.file $srcdir/configure"; then
+
+	# If neither matched, then we have a broken ls.  This can happen
+	# if, for instance, CONFIG_SHELL is bash and it inherits a
+	# broken ls alias from the environment.  This has actually
+	# happened.  Such a system could not be considered "sane".
+	as_fn_error $? "ls -t appears to fail.  Make sure there is not a broken
+  alias in your environment" "$LINENO" 5
+     fi
+     if test "$2" = conftest.file || test $am_try -eq 2; then
+       break
+     fi
+     # Just in case.
+     sleep 1
+     am_has_slept=yes
+   done
+   test "$2" = conftest.file
+   )
+then
+   # Ok.
+   :
+else
+   as_fn_error $? "newly created file is older than distributed files!
+Check your system clock" "$LINENO" 5
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+# If we didn't sleep, we still need to ensure time stamps of config.status and
+# generated files are strictly newer.
+am_sleep_pid=
+if grep 'slept: no' conftest.file >/dev/null 2>&1; then
+  ( sleep 1 ) &
+  am_sleep_pid=$!
+fi
+
+rm -f conftest.file
+
+test "$program_prefix" != NONE &&
+  program_transform_name="s&^&$program_prefix&;$program_transform_name"
+# Use a double $ so make ignores it.
+test "$program_suffix" != NONE &&
+  program_transform_name="s&\$&$program_suffix&;$program_transform_name"
+# Double any \ or $.
+# By default was 's,x,x', remove it if useless.
+ac_script='s/[\\$]/&&/g;s/;s,x,x,$//'
+program_transform_name=`printf "%s\n" "$program_transform_name" | sed "$ac_script"`
+
+
+# Expand $ac_aux_dir to an absolute path.
+am_aux_dir=`cd "$ac_aux_dir" && pwd`
+
+
+  if test x"${MISSING+set}" != xset; then
+  MISSING="\${SHELL} '$am_aux_dir/missing'"
+fi
+# Use eval to expand $SHELL
+if eval "$MISSING --is-lightweight"; then
+  am_missing_run="$MISSING "
+else
+  am_missing_run=
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: 'missing' script is too old or missing" >&5
+printf "%s\n" "$as_me: WARNING: 'missing' script is too old or missing" >&2;}
+fi
+
+if test x"${install_sh+set}" != xset; then
+  case $am_aux_dir in
+  *\ * | *\	*)
+    install_sh="\${SHELL} '$am_aux_dir/install-sh'" ;;
+  *)
+    install_sh="\${SHELL} $am_aux_dir/install-sh"
+  esac
+fi
+
+# Installed binaries are usually stripped using 'strip' when the user
+# run "make install-strip".  However 'strip' might not be the right
+# tool to use in cross-compilation environments, therefore Automake
+# will honor the 'STRIP' environment variable to overrule this program.
+if test "$cross_compiling" != no; then
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}strip", so it can be a program name with args.
+set dummy ${ac_tool_prefix}strip; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_STRIP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$STRIP"; then
+  ac_cv_prog_STRIP="$STRIP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_STRIP="${ac_tool_prefix}strip"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+STRIP=$ac_cv_prog_STRIP
+if test -n "$STRIP"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $STRIP" >&5
+printf "%s\n" "$STRIP" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_STRIP"; then
+  ac_ct_STRIP=$STRIP
+  # Extract the first word of "strip", so it can be a program name with args.
+set dummy strip; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_STRIP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_STRIP"; then
+  ac_cv_prog_ac_ct_STRIP="$ac_ct_STRIP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_STRIP="strip"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_STRIP=$ac_cv_prog_ac_ct_STRIP
+if test -n "$ac_ct_STRIP"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_STRIP" >&5
+printf "%s\n" "$ac_ct_STRIP" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_STRIP" = x; then
+    STRIP=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    STRIP=$ac_ct_STRIP
+  fi
+else
+  STRIP="$ac_cv_prog_STRIP"
+fi
+
+fi
+INSTALL_STRIP_PROGRAM="\$(install_sh) -c -s"
+
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for a race-free mkdir -p" >&5
+printf %s "checking for a race-free mkdir -p... " >&6; }
+if test -z "$MKDIR_P"; then
+  if test ${ac_cv_path_mkdir+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/opt/sfw/bin
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_prog in mkdir gmkdir; do
+	 for ac_exec_ext in '' $ac_executable_extensions; do
+	   as_fn_executable_p "$as_dir$ac_prog$ac_exec_ext" || continue
+	   case `"$as_dir$ac_prog$ac_exec_ext" --version 2>&1` in #(
+	     'mkdir ('*'coreutils) '* | \
+	     *'BusyBox '* | \
+	     'mkdir (fileutils) '4.1*)
+	       ac_cv_path_mkdir=$as_dir$ac_prog$ac_exec_ext
+	       break 3;;
+	   esac
+	 done
+       done
+  done
+IFS=$as_save_IFS
+ ;;
+esac
+fi
+
+  test -d ./--version && rmdir ./--version
+  if test ${ac_cv_path_mkdir+y}; then
+    MKDIR_P="$ac_cv_path_mkdir -p"
+  else
+    # As a last resort, use plain mkdir -p,
+    # in the hope it doesn't have the bugs of ancient mkdir.
+    MKDIR_P='mkdir -p'
+  fi
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $MKDIR_P" >&5
+printf "%s\n" "$MKDIR_P" >&6; }
+
+for ac_prog in gawk mawk nawk awk
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_AWK+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$AWK"; then
+  ac_cv_prog_AWK="$AWK" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AWK="$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+AWK=$ac_cv_prog_AWK
+if test -n "$AWK"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $AWK" >&5
+printf "%s\n" "$AWK" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  test -n "$AWK" && break
+done
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether ${MAKE-make} sets \$(MAKE)" >&5
+printf %s "checking whether ${MAKE-make} sets \$(MAKE)... " >&6; }
+set x ${MAKE-make}
+ac_make=`printf "%s\n" "$2" | sed 's/+/p/g; s/[^a-zA-Z0-9_]/_/g'`
+if eval test \${ac_cv_prog_make_${ac_make}_set+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat >conftest.make <<\_ACEOF
+SHELL = /bin/sh
+all:
+	@echo '@@@%%%=$(MAKE)=@@@%%%'
+_ACEOF
+# GNU make sometimes prints "make[1]: Entering ...", which would confuse us.
+case `${MAKE-make} -f conftest.make 2>/dev/null` in
+  *@@@%%%=?*=@@@%%%*)
+    eval ac_cv_prog_make_${ac_make}_set=yes;;
+  *)
+    eval ac_cv_prog_make_${ac_make}_set=no;;
+esac
+rm -f conftest.make ;;
+esac
+fi
+if eval test \$ac_cv_prog_make_${ac_make}_set = yes; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+  SET_MAKE=
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+  SET_MAKE="MAKE=${MAKE-make}"
+fi
+
+rm -rf .tst 2>/dev/null
+mkdir .tst 2>/dev/null
+if test -d .tst; then
+  am__leading_dot=.
+else
+  am__leading_dot=_
+fi
+rmdir .tst 2>/dev/null
+
+# Check whether --enable-silent-rules was given.
+if test ${enable_silent_rules+y}
+then :
+  enableval=$enable_silent_rules;
+fi
+
+case $enable_silent_rules in # (((
+  yes) AM_DEFAULT_VERBOSITY=0;;
+   no) AM_DEFAULT_VERBOSITY=1;;
+    *) AM_DEFAULT_VERBOSITY=1;;
+esac
+am_make=${MAKE-make}
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether $am_make supports nested variables" >&5
+printf %s "checking whether $am_make supports nested variables... " >&6; }
+if test ${am_cv_make_support_nested_variables+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if printf "%s\n" 'TRUE=$(BAR$(V))
+BAR0=false
+BAR1=true
+V=1
+am__doit:
+	@$(TRUE)
+.PHONY: am__doit' | $am_make -f - >/dev/null 2>&1; then
+  am_cv_make_support_nested_variables=yes
+else
+  am_cv_make_support_nested_variables=no
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $am_cv_make_support_nested_variables" >&5
+printf "%s\n" "$am_cv_make_support_nested_variables" >&6; }
+if test $am_cv_make_support_nested_variables = yes; then
+    AM_V='$(V)'
+  AM_DEFAULT_V='$(AM_DEFAULT_VERBOSITY)'
+else
+  AM_V=$AM_DEFAULT_VERBOSITY
+  AM_DEFAULT_V=$AM_DEFAULT_VERBOSITY
+fi
+AM_BACKSLASH='\'
+
+if test "`cd $srcdir && pwd`" != "`pwd`"; then
+  # Use -I$(srcdir) only when $(srcdir) != ., so that make's output
+  # is not polluted with repeated "-I."
+  am__isrc=' -I$(srcdir)'
+  # test to see if srcdir already configured
+  if test -f $srcdir/config.status; then
+    as_fn_error $? "source directory already configured; run \"make distclean\" there first" "$LINENO" 5
+  fi
+fi
+
+# test whether we have cygpath
+if test -z "$CYGPATH_W"; then
+  if (cygpath --version) >/dev/null 2>/dev/null; then
+    CYGPATH_W='cygpath -w'
+  else
+    CYGPATH_W=echo
+  fi
+fi
+
+
+# Define the identity of the package.
+ PACKAGE='libpng'
+ VERSION='1.6.43'
+
+
+printf "%s\n" "#define PACKAGE \"$PACKAGE\"" >>confdefs.h
+
+
+printf "%s\n" "#define VERSION \"$VERSION\"" >>confdefs.h
+
+# Some tools Automake needs.
+
+ACLOCAL=${ACLOCAL-"${am_missing_run}aclocal-${am__api_version}"}
+
+
+AUTOCONF=${AUTOCONF-"${am_missing_run}autoconf"}
+
+
+AUTOMAKE=${AUTOMAKE-"${am_missing_run}automake-${am__api_version}"}
+
+
+AUTOHEADER=${AUTOHEADER-"${am_missing_run}autoheader"}
+
+
+MAKEINFO=${MAKEINFO-"${am_missing_run}makeinfo"}
+
+# For better backward compatibility.  To be removed once Automake 1.9.x
+# dies out for good.  For more background, see:
+# <https://lists.gnu.org/archive/html/automake/2012-07/msg00001.html>
+# <https://lists.gnu.org/archive/html/automake/2012-07/msg00014.html>
+mkdir_p='$(MKDIR_P)'
+
+# We need awk for the "check" target (and possibly the TAP driver).  The
+# system "awk" is bad on some platforms.
+# Always define AMTAR for backward compatibility.  Yes, it's still used
+# in the wild :-(  We should find a proper way to deprecate it ...
+AMTAR='$${TAR-tar}'
+
+
+# We'll loop over all known methods to create a tar archive until one works.
+_am_tools='gnutar  pax cpio none'
+
+am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'
+
+
+
+
+
+# Variables for tags utilities; see am/tags.am
+if test -z "$CTAGS"; then
+  CTAGS=ctags
+fi
+
+if test -z "$ETAGS"; then
+  ETAGS=etags
+fi
+
+if test -z "$CSCOPE"; then
+  CSCOPE=cscope
+fi
+
+
+
+# POSIX will say in a future version that running "rm -f" with no argument
+# is OK; and we want to be able to make that assumption in our Makefile
+# recipes.  So use an aggressive probe to check that the usage we want is
+# actually supported "in the wild" to an acceptable degree.
+# See automake bug#10828.
+# To make any issue more visible, cause the running configure to be aborted
+# by default if the 'rm' program in use doesn't match our expectations; the
+# user can still override this though.
+if rm -f && rm -fr && rm -rf; then : OK; else
+  cat >&2 <<'END'
+Oops!
+
+Your 'rm' program seems unable to run without file operands specified
+on the command line, even when the '-f' option is present.  This is contrary
+to the behaviour of most rm programs out there, and not conforming with
+the upcoming POSIX standard: <http://austingroupbugs.net/view.php?id=542>
+
+Please tell bug-automake@gnu.org about your system, including the value
+of your $PATH and any error possibly output before this message.  This
+can help us improve future automake versions.
+
+END
+  if test x"$ACCEPT_INFERIOR_RM_PROGRAM" = x"yes"; then
+    echo 'Configuration will proceed anyway, since you have set the' >&2
+    echo 'ACCEPT_INFERIOR_RM_PROGRAM variable to "yes"' >&2
+    echo >&2
+  else
+    cat >&2 <<'END'
+Aborting the configuration process, to ensure you take notice of the issue.
+
+You can download and install GNU coreutils to get an 'rm' implementation
+that behaves properly: <https://www.gnu.org/software/coreutils/>.
+
+If you want to complete the configuration process using your problematic
+'rm' anyway, export the environment variable ACCEPT_INFERIOR_RM_PROGRAM
+to "yes", and re-run configure.
+
+END
+    as_fn_error $? "Your 'rm' program is bad, sorry." "$LINENO" 5
+  fi
+fi
+
+# The following line causes --disable-maintainer-mode to be the default to
+# configure. This is necessary because libpng distributions cannot rely on the
+# time stamps of the autotools generated files being correct
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether to enable maintainer-specific portions of Makefiles" >&5
+printf %s "checking whether to enable maintainer-specific portions of Makefiles... " >&6; }
+    # Check whether --enable-maintainer-mode was given.
+if test ${enable_maintainer_mode+y}
+then :
+  enableval=$enable_maintainer_mode; USE_MAINTAINER_MODE=$enableval
+else case e in #(
+  e) USE_MAINTAINER_MODE=no ;;
+esac
+fi
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $USE_MAINTAINER_MODE" >&5
+printf "%s\n" "$USE_MAINTAINER_MODE" >&6; }
+   if test $USE_MAINTAINER_MODE = yes; then
+  MAINTAINER_MODE_TRUE=
+  MAINTAINER_MODE_FALSE='#'
+else
+  MAINTAINER_MODE_TRUE='#'
+  MAINTAINER_MODE_FALSE=
+fi
+
+  MAINT=$MAINTAINER_MODE_TRUE
+
+
+
+
+PNGLIB_VERSION=1.6.43
+PNGLIB_MAJOR=1
+PNGLIB_MINOR=6
+PNGLIB_RELEASE=43
+
+
+
+ac_config_headers="$ac_config_headers config.h"
+
+
+# Check for basic programs.
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+
+
+
+
+
+
+
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}gcc", so it can be a program name with args.
+set dummy ${ac_tool_prefix}gcc; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="${ac_tool_prefix}gcc"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_CC"; then
+  ac_ct_CC=$CC
+  # Extract the first word of "gcc", so it can be a program name with args.
+set dummy gcc; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_CC+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_CC"; then
+  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_CC="gcc"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_CC=$ac_cv_prog_ac_ct_CC
+if test -n "$ac_ct_CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
+printf "%s\n" "$ac_ct_CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_CC" = x; then
+    CC=""
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    CC=$ac_ct_CC
+  fi
+else
+  CC="$ac_cv_prog_CC"
+fi
+
+if test -z "$CC"; then
+          if test -n "$ac_tool_prefix"; then
+    # Extract the first word of "${ac_tool_prefix}cc", so it can be a program name with args.
+set dummy ${ac_tool_prefix}cc; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="${ac_tool_prefix}cc"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  fi
+fi
+if test -z "$CC"; then
+  # Extract the first word of "cc", so it can be a program name with args.
+set dummy cc; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+  ac_prog_rejected=no
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    if test "$as_dir$ac_word$ac_exec_ext" = "/usr/ucb/cc"; then
+       ac_prog_rejected=yes
+       continue
+     fi
+    ac_cv_prog_CC="cc"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+if test $ac_prog_rejected = yes; then
+  # We found a bogon in the path, so make sure we never use it.
+  set dummy $ac_cv_prog_CC
+  shift
+  if test $# != 0; then
+    # We chose a different compiler from the bogus one.
+    # However, it has the same basename, so the bogon will be chosen
+    # first if we set CC to just the basename; use the full file name.
+    shift
+    ac_cv_prog_CC="$as_dir$ac_word${1+' '}$@"
+  fi
+fi
+fi ;;
+esac
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$CC"; then
+  if test -n "$ac_tool_prefix"; then
+  for ac_prog in cl.exe
+  do
+    # Extract the first word of "$ac_tool_prefix$ac_prog", so it can be a program name with args.
+set dummy $ac_tool_prefix$ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="$ac_tool_prefix$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+    test -n "$CC" && break
+  done
+fi
+if test -z "$CC"; then
+  ac_ct_CC=$CC
+  for ac_prog in cl.exe
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_CC+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_CC"; then
+  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_CC="$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_CC=$ac_cv_prog_ac_ct_CC
+if test -n "$ac_ct_CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
+printf "%s\n" "$ac_ct_CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  test -n "$ac_ct_CC" && break
+done
+
+  if test "x$ac_ct_CC" = x; then
+    CC=""
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    CC=$ac_ct_CC
+  fi
+fi
+
+fi
+if test -z "$CC"; then
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}clang", so it can be a program name with args.
+set dummy ${ac_tool_prefix}clang; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="${ac_tool_prefix}clang"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_CC"; then
+  ac_ct_CC=$CC
+  # Extract the first word of "clang", so it can be a program name with args.
+set dummy clang; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_CC+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_CC"; then
+  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_CC="clang"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_CC=$ac_cv_prog_ac_ct_CC
+if test -n "$ac_ct_CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
+printf "%s\n" "$ac_ct_CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_CC" = x; then
+    CC=""
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    CC=$ac_ct_CC
+  fi
+else
+  CC="$ac_cv_prog_CC"
+fi
+
+fi
+
+
+test -z "$CC" && { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+as_fn_error $? "no acceptable C compiler found in \$PATH
+See 'config.log' for more details" "$LINENO" 5; }
+
+# Provide some information about the compiler.
+printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for C compiler version" >&5
+set X $ac_compile
+ac_compiler=$2
+for ac_option in --version -v -V -qversion -version; do
+  { { ac_try="$ac_compiler $ac_option >&5"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_compiler $ac_option >&5") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    sed '10a\
+... rest of stderr output deleted ...
+         10q' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+  fi
+  rm -f conftest.er1 conftest.err
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+done
+
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+ac_clean_files_save=$ac_clean_files
+ac_clean_files="$ac_clean_files a.out a.out.dSYM a.exe b.out"
+# Try to create an executable without -o first, disregard a.out.
+# It will help us diagnose broken compilers, and finding out an intuition
+# of exeext.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the C compiler works" >&5
+printf %s "checking whether the C compiler works... " >&6; }
+ac_link_default=`printf "%s\n" "$ac_link" | sed 's/ -o *conftest[^ ]*//'`
+
+# The possible output files:
+ac_files="a.out conftest.exe conftest a.exe a_out.exe b.out conftest.*"
+
+ac_rmfiles=
+for ac_file in $ac_files
+do
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM | *.o | *.obj ) ;;
+    * ) ac_rmfiles="$ac_rmfiles $ac_file";;
+  esac
+done
+rm -f $ac_rmfiles
+
+if { { ac_try="$ac_link_default"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_link_default") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+then :
+  # Autoconf-2.13 could set the ac_cv_exeext variable to 'no'.
+# So ignore a value of 'no', otherwise this would lead to 'EXEEXT = no'
+# in a Makefile.  We should not override ac_cv_exeext if it was cached,
+# so that the user can short-circuit this test for compilers unknown to
+# Autoconf.
+for ac_file in $ac_files ''
+do
+  test -f "$ac_file" || continue
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM | *.o | *.obj )
+	;;
+    [ab].out )
+	# We found the default executable, but exeext='' is most
+	# certainly right.
+	break;;
+    *.* )
+	if test ${ac_cv_exeext+y} && test "$ac_cv_exeext" != no;
+	then :; else
+	   ac_cv_exeext=`expr "$ac_file" : '[^.]*\(\..*\)'`
+	fi
+	# We set ac_cv_exeext here because the later test for it is not
+	# safe: cross compilers may not add the suffix if given an '-o'
+	# argument, so we may need to know it at that point already.
+	# Even if this section looks crufty: it has the advantage of
+	# actually working.
+	break;;
+    * )
+	break;;
+  esac
+done
+test "$ac_cv_exeext" = no && ac_cv_exeext=
+
+else case e in #(
+  e) ac_file='' ;;
+esac
+fi
+if test -z "$ac_file"
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+printf "%s\n" "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+as_fn_error 77 "C compiler cannot create executables
+See 'config.log' for more details" "$LINENO" 5; }
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; } ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for C compiler default output file name" >&5
+printf %s "checking for C compiler default output file name... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_file" >&5
+printf "%s\n" "$ac_file" >&6; }
+ac_exeext=$ac_cv_exeext
+
+rm -f -r a.out a.out.dSYM a.exe conftest$ac_cv_exeext b.out
+ac_clean_files=$ac_clean_files_save
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for suffix of executables" >&5
+printf %s "checking for suffix of executables... " >&6; }
+if { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+then :
+  # If both 'conftest.exe' and 'conftest' are 'present' (well, observable)
+# catch 'conftest.exe'.  For instance with Cygwin, 'ls conftest' will
+# work properly (i.e., refer to 'conftest.exe'), while it won't with
+# 'rm'.
+for ac_file in conftest.exe conftest conftest.*; do
+  test -f "$ac_file" || continue
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM | *.o | *.obj ) ;;
+    *.* ) ac_cv_exeext=`expr "$ac_file" : '[^.]*\(\..*\)'`
+	  break;;
+    * ) break;;
+  esac
+done
+else case e in #(
+  e) { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+as_fn_error $? "cannot compute suffix of executables: cannot compile and link
+See 'config.log' for more details" "$LINENO" 5; } ;;
+esac
+fi
+rm -f conftest conftest$ac_cv_exeext
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_exeext" >&5
+printf "%s\n" "$ac_cv_exeext" >&6; }
+
+rm -f conftest.$ac_ext
+EXEEXT=$ac_cv_exeext
+ac_exeext=$EXEEXT
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdio.h>
+int
+main (void)
+{
+FILE *f = fopen ("conftest.out", "w");
+ if (!f)
+  return 1;
+ return ferror (f) || fclose (f) != 0;
+
+  ;
+  return 0;
+}
+_ACEOF
+ac_clean_files="$ac_clean_files conftest.out"
+# Check that the compiler produces executables we can run.  If not, either
+# the compiler is broken, or we cross compile.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether we are cross compiling" >&5
+printf %s "checking whether we are cross compiling... " >&6; }
+if test "$cross_compiling" != yes; then
+  { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+  if { ac_try='./conftest$ac_cv_exeext'
+  { { case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }; then
+    cross_compiling=no
+  else
+    if test "$cross_compiling" = maybe; then
+	cross_compiling=yes
+    else
+	{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+as_fn_error 77 "cannot run C compiled programs.
+If you meant to cross compile, use '--host'.
+See 'config.log' for more details" "$LINENO" 5; }
+    fi
+  fi
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $cross_compiling" >&5
+printf "%s\n" "$cross_compiling" >&6; }
+
+rm -f conftest.$ac_ext conftest$ac_cv_exeext \
+  conftest.o conftest.obj conftest.out
+ac_clean_files=$ac_clean_files_save
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for suffix of object files" >&5
+printf %s "checking for suffix of object files... " >&6; }
+if test ${ac_cv_objext+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.o conftest.obj
+if { { ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_compile") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+then :
+  for ac_file in conftest.o conftest.obj conftest.*; do
+  test -f "$ac_file" || continue;
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM ) ;;
+    *) ac_cv_objext=`expr "$ac_file" : '.*\.\(.*\)'`
+       break;;
+  esac
+done
+else case e in #(
+  e) printf "%s\n" "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+as_fn_error $? "cannot compute suffix of object files: cannot compile
+See 'config.log' for more details" "$LINENO" 5; } ;;
+esac
+fi
+rm -f conftest.$ac_cv_objext conftest.$ac_ext ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_objext" >&5
+printf "%s\n" "$ac_cv_objext" >&6; }
+OBJEXT=$ac_cv_objext
+ac_objext=$OBJEXT
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the compiler supports GNU C" >&5
+printf %s "checking whether the compiler supports GNU C... " >&6; }
+if test ${ac_cv_c_compiler_gnu+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+#ifndef __GNUC__
+       choke me
+#endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_compiler_gnu=yes
+else case e in #(
+  e) ac_compiler_gnu=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+ac_cv_c_compiler_gnu=$ac_compiler_gnu
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_c_compiler_gnu" >&5
+printf "%s\n" "$ac_cv_c_compiler_gnu" >&6; }
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+if test $ac_compiler_gnu = yes; then
+  GCC=yes
+else
+  GCC=
+fi
+ac_test_CFLAGS=${CFLAGS+y}
+ac_save_CFLAGS=$CFLAGS
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether $CC accepts -g" >&5
+printf %s "checking whether $CC accepts -g... " >&6; }
+if test ${ac_cv_prog_cc_g+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_save_c_werror_flag=$ac_c_werror_flag
+   ac_c_werror_flag=yes
+   ac_cv_prog_cc_g=no
+   CFLAGS="-g"
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_g=yes
+else case e in #(
+  e) CFLAGS=""
+      cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+
+else case e in #(
+  e) ac_c_werror_flag=$ac_save_c_werror_flag
+	 CFLAGS="-g"
+	 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_g=yes
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+   ac_c_werror_flag=$ac_save_c_werror_flag ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_g" >&5
+printf "%s\n" "$ac_cv_prog_cc_g" >&6; }
+if test $ac_test_CFLAGS; then
+  CFLAGS=$ac_save_CFLAGS
+elif test $ac_cv_prog_cc_g = yes; then
+  if test "$GCC" = yes; then
+    CFLAGS="-g -O2"
+  else
+    CFLAGS="-g"
+  fi
+else
+  if test "$GCC" = yes; then
+    CFLAGS="-O2"
+  else
+    CFLAGS=
+  fi
+fi
+ac_prog_cc_stdc=no
+if test x$ac_prog_cc_stdc = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CC option to enable C11 features" >&5
+printf %s "checking for $CC option to enable C11 features... " >&6; }
+if test ${ac_cv_prog_cc_c11+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_cv_prog_cc_c11=no
+ac_save_CC=$CC
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$ac_c_conftest_c11_program
+_ACEOF
+for ac_arg in '' -std=gnu11
+do
+  CC="$ac_save_CC $ac_arg"
+  if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_c11=$ac_arg
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam
+  test "x$ac_cv_prog_cc_c11" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CC=$ac_save_CC ;;
+esac
+fi
+
+if test "x$ac_cv_prog_cc_c11" = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+printf "%s\n" "unsupported" >&6; }
+else case e in #(
+  e) if test "x$ac_cv_prog_cc_c11" = x
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+printf "%s\n" "none needed" >&6; }
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c11" >&5
+printf "%s\n" "$ac_cv_prog_cc_c11" >&6; }
+     CC="$CC $ac_cv_prog_cc_c11" ;;
+esac
+fi
+  ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c11
+  ac_prog_cc_stdc=c11 ;;
+esac
+fi
+fi
+if test x$ac_prog_cc_stdc = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CC option to enable C99 features" >&5
+printf %s "checking for $CC option to enable C99 features... " >&6; }
+if test ${ac_cv_prog_cc_c99+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_cv_prog_cc_c99=no
+ac_save_CC=$CC
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$ac_c_conftest_c99_program
+_ACEOF
+for ac_arg in '' -std=gnu99 -std=c99 -c99 -qlanglvl=extc1x -qlanglvl=extc99 -AC99 -D_STDC_C99=
+do
+  CC="$ac_save_CC $ac_arg"
+  if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_c99=$ac_arg
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam
+  test "x$ac_cv_prog_cc_c99" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CC=$ac_save_CC ;;
+esac
+fi
+
+if test "x$ac_cv_prog_cc_c99" = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+printf "%s\n" "unsupported" >&6; }
+else case e in #(
+  e) if test "x$ac_cv_prog_cc_c99" = x
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+printf "%s\n" "none needed" >&6; }
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c99" >&5
+printf "%s\n" "$ac_cv_prog_cc_c99" >&6; }
+     CC="$CC $ac_cv_prog_cc_c99" ;;
+esac
+fi
+  ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c99
+  ac_prog_cc_stdc=c99 ;;
+esac
+fi
+fi
+if test x$ac_prog_cc_stdc = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CC option to enable C89 features" >&5
+printf %s "checking for $CC option to enable C89 features... " >&6; }
+if test ${ac_cv_prog_cc_c89+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_cv_prog_cc_c89=no
+ac_save_CC=$CC
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$ac_c_conftest_c89_program
+_ACEOF
+for ac_arg in '' -qlanglvl=extc89 -qlanglvl=ansi -std -Ae "-Aa -D_HPUX_SOURCE" "-Xc -D__EXTENSIONS__"
+do
+  CC="$ac_save_CC $ac_arg"
+  if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_c89=$ac_arg
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam
+  test "x$ac_cv_prog_cc_c89" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CC=$ac_save_CC ;;
+esac
+fi
+
+if test "x$ac_cv_prog_cc_c89" = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+printf "%s\n" "unsupported" >&6; }
+else case e in #(
+  e) if test "x$ac_cv_prog_cc_c89" = x
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+printf "%s\n" "none needed" >&6; }
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c89" >&5
+printf "%s\n" "$ac_cv_prog_cc_c89" >&6; }
+     CC="$CC $ac_cv_prog_cc_c89" ;;
+esac
+fi
+  ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c89
+  ac_prog_cc_stdc=c89 ;;
+esac
+fi
+fi
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+  ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether $CC understands -c and -o together" >&5
+printf %s "checking whether $CC understands -c and -o together... " >&6; }
+if test ${am_cv_prog_cc_c_o+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+  # Make sure it works both with $CC and with simple cc.
+  # Following AC_PROG_CC_C_O, we do the test twice because some
+  # compilers refuse to overwrite an existing .o file with -o,
+  # though they will create one.
+  am_cv_prog_cc_c_o=yes
+  for am_i in 1 2; do
+    if { echo "$as_me:$LINENO: $CC -c conftest.$ac_ext -o conftest2.$ac_objext" >&5
+   ($CC -c conftest.$ac_ext -o conftest2.$ac_objext) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); } \
+         && test -f conftest2.$ac_objext; then
+      : OK
+    else
+      am_cv_prog_cc_c_o=no
+      break
+    fi
+  done
+  rm -f core conftest*
+  unset am_i ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $am_cv_prog_cc_c_o" >&5
+printf "%s\n" "$am_cv_prog_cc_c_o" >&6; }
+if test "$am_cv_prog_cc_c_o" != yes; then
+   # Losing compiler, so override with the script.
+   # FIXME: It is wrong to rewrite CC.
+   # But if we don't then we get into trouble of one sort or another.
+   # A longer-term fix would be to have automake use am__CC in this case,
+   # and then we could set am__CC="\$(top_srcdir)/compile \$(CC)"
+   CC="$am_aux_dir/compile $CC"
+fi
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+DEPDIR="${am__leading_dot}deps"
+
+ac_config_commands="$ac_config_commands depfiles"
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether ${MAKE-make} supports the include directive" >&5
+printf %s "checking whether ${MAKE-make} supports the include directive... " >&6; }
+cat > confinc.mk << 'END'
+am__doit:
+	@echo this is the am__doit target >confinc.out
+.PHONY: am__doit
+END
+am__include="#"
+am__quote=
+# BSD make does it like this.
+echo '.include "confinc.mk" # ignored' > confmf.BSD
+# Other make implementations (GNU, Solaris 10, AIX) do it like this.
+echo 'include confinc.mk # ignored' > confmf.GNU
+_am_result=no
+for s in GNU BSD; do
+  { echo "$as_me:$LINENO: ${MAKE-make} -f confmf.$s && cat confinc.out" >&5
+   (${MAKE-make} -f confmf.$s && cat confinc.out) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); }
+  case $?:`cat confinc.out 2>/dev/null` in #(
+  '0:this is the am__doit target') :
+    case $s in #(
+  BSD) :
+    am__include='.include' am__quote='"' ;; #(
+  *) :
+    am__include='include' am__quote='' ;;
+esac ;; #(
+  *) :
+     ;;
+esac
+  if test "$am__include" != "#"; then
+    _am_result="yes ($s style)"
+    break
+  fi
+done
+rm -f confinc.* confmf.*
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: ${_am_result}" >&5
+printf "%s\n" "${_am_result}" >&6; }
+
+# Check whether --enable-dependency-tracking was given.
+if test ${enable_dependency_tracking+y}
+then :
+  enableval=$enable_dependency_tracking;
+fi
+
+if test "x$enable_dependency_tracking" != xno; then
+  am_depcomp="$ac_aux_dir/depcomp"
+  AMDEPBACKSLASH='\'
+  am__nodep='_no'
+fi
+ if test "x$enable_dependency_tracking" != xno; then
+  AMDEP_TRUE=
+  AMDEP_FALSE='#'
+else
+  AMDEP_TRUE='#'
+  AMDEP_FALSE=
+fi
+
+
+
+depcc="$CC"   am_compiler_list=
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking dependency style of $depcc" >&5
+printf %s "checking dependency style of $depcc... " >&6; }
+if test ${am_cv_CC_dependencies_compiler_type+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -z "$AMDEP_TRUE" && test -f "$am_depcomp"; then
+  # We make a subdir and do the tests there.  Otherwise we can end up
+  # making bogus files that we don't know about and never remove.  For
+  # instance it was reported that on HP-UX the gcc test will end up
+  # making a dummy file named 'D' -- because '-MD' means "put the output
+  # in D".
+  rm -rf conftest.dir
+  mkdir conftest.dir
+  # Copy depcomp to subdir because otherwise we won't find it if we're
+  # using a relative directory.
+  cp "$am_depcomp" conftest.dir
+  cd conftest.dir
+  # We will build objects and dependencies in a subdirectory because
+  # it helps to detect inapplicable dependency modes.  For instance
+  # both Tru64's cc and ICC support -MD to output dependencies as a
+  # side effect of compilation, but ICC will put the dependencies in
+  # the current directory while Tru64 will put them in the object
+  # directory.
+  mkdir sub
+
+  am_cv_CC_dependencies_compiler_type=none
+  if test "$am_compiler_list" = ""; then
+     am_compiler_list=`sed -n 's/^#*\([a-zA-Z0-9]*\))$/\1/p' < ./depcomp`
+  fi
+  am__universal=false
+  case " $depcc " in #(
+     *\ -arch\ *\ -arch\ *) am__universal=true ;;
+     esac
+
+  for depmode in $am_compiler_list; do
+    # Setup a source with many dependencies, because some compilers
+    # like to wrap large dependency lists on column 80 (with \), and
+    # we should not choose a depcomp mode which is confused by this.
+    #
+    # We need to recreate these files for each test, as the compiler may
+    # overwrite some of them when testing with obscure command lines.
+    # This happens at least with the AIX C compiler.
+    : > sub/conftest.c
+    for i in 1 2 3 4 5 6; do
+      echo '#include "conftst'$i'.h"' >> sub/conftest.c
+      # Using ": > sub/conftst$i.h" creates only sub/conftst1.h with
+      # Solaris 10 /bin/sh.
+      echo '/* dummy */' > sub/conftst$i.h
+    done
+    echo "${am__include} ${am__quote}sub/conftest.Po${am__quote}" > confmf
+
+    # We check with '-c' and '-o' for the sake of the "dashmstdout"
+    # mode.  It turns out that the SunPro C++ compiler does not properly
+    # handle '-M -o', and we need to detect this.  Also, some Intel
+    # versions had trouble with output in subdirs.
+    am__obj=sub/conftest.${OBJEXT-o}
+    am__minus_obj="-o $am__obj"
+    case $depmode in
+    gcc)
+      # This depmode causes a compiler race in universal mode.
+      test "$am__universal" = false || continue
+      ;;
+    nosideeffect)
+      # After this tag, mechanisms are not by side-effect, so they'll
+      # only be used when explicitly requested.
+      if test "x$enable_dependency_tracking" = xyes; then
+	continue
+      else
+	break
+      fi
+      ;;
+    msvc7 | msvc7msys | msvisualcpp | msvcmsys)
+      # This compiler won't grok '-c -o', but also, the minuso test has
+      # not run yet.  These depmodes are late enough in the game, and
+      # so weak that their functioning should not be impacted.
+      am__obj=conftest.${OBJEXT-o}
+      am__minus_obj=
+      ;;
+    none) break ;;
+    esac
+    if depmode=$depmode \
+       source=sub/conftest.c object=$am__obj \
+       depfile=sub/conftest.Po tmpdepfile=sub/conftest.TPo \
+       $SHELL ./depcomp $depcc -c $am__minus_obj sub/conftest.c \
+         >/dev/null 2>conftest.err &&
+       grep sub/conftst1.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep sub/conftst6.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep $am__obj sub/conftest.Po > /dev/null 2>&1 &&
+       ${MAKE-make} -s -f confmf > /dev/null 2>&1; then
+      # icc doesn't choke on unknown options, it will just issue warnings
+      # or remarks (even with -Werror).  So we grep stderr for any message
+      # that says an option was ignored or not supported.
+      # When given -MP, icc 7.0 and 7.1 complain thusly:
+      #   icc: Command line warning: ignoring option '-M'; no argument required
+      # The diagnosis changed in icc 8.0:
+      #   icc: Command line remark: option '-MP' not supported
+      if (grep 'ignoring option' conftest.err ||
+          grep 'not supported' conftest.err) >/dev/null 2>&1; then :; else
+        am_cv_CC_dependencies_compiler_type=$depmode
+        break
+      fi
+    fi
+  done
+
+  cd ..
+  rm -rf conftest.dir
+else
+  am_cv_CC_dependencies_compiler_type=none
+fi
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $am_cv_CC_dependencies_compiler_type" >&5
+printf "%s\n" "$am_cv_CC_dependencies_compiler_type" >&6; }
+CCDEPMODE=depmode=$am_cv_CC_dependencies_compiler_type
+
+ if
+  test "x$enable_dependency_tracking" != xno \
+  && test "$am_cv_CC_dependencies_compiler_type" = gcc3; then
+  am__fastdepCC_TRUE=
+  am__fastdepCC_FALSE='#'
+else
+  am__fastdepCC_TRUE='#'
+  am__fastdepCC_FALSE=
+fi
+
+
+# By default we simply use the C compiler to build assembly code.
+
+test "${CCAS+set}" = set || CCAS=$CC
+test "${CCASFLAGS+set}" = set || CCASFLAGS=$CFLAGS
+
+
+
+depcc="$CCAS"   am_compiler_list=
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking dependency style of $depcc" >&5
+printf %s "checking dependency style of $depcc... " >&6; }
+if test ${am_cv_CCAS_dependencies_compiler_type+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -z "$AMDEP_TRUE" && test -f "$am_depcomp"; then
+  # We make a subdir and do the tests there.  Otherwise we can end up
+  # making bogus files that we don't know about and never remove.  For
+  # instance it was reported that on HP-UX the gcc test will end up
+  # making a dummy file named 'D' -- because '-MD' means "put the output
+  # in D".
+  rm -rf conftest.dir
+  mkdir conftest.dir
+  # Copy depcomp to subdir because otherwise we won't find it if we're
+  # using a relative directory.
+  cp "$am_depcomp" conftest.dir
+  cd conftest.dir
+  # We will build objects and dependencies in a subdirectory because
+  # it helps to detect inapplicable dependency modes.  For instance
+  # both Tru64's cc and ICC support -MD to output dependencies as a
+  # side effect of compilation, but ICC will put the dependencies in
+  # the current directory while Tru64 will put them in the object
+  # directory.
+  mkdir sub
+
+  am_cv_CCAS_dependencies_compiler_type=none
+  if test "$am_compiler_list" = ""; then
+     am_compiler_list=`sed -n 's/^#*\([a-zA-Z0-9]*\))$/\1/p' < ./depcomp`
+  fi
+  am__universal=false
+
+
+  for depmode in $am_compiler_list; do
+    # Setup a source with many dependencies, because some compilers
+    # like to wrap large dependency lists on column 80 (with \), and
+    # we should not choose a depcomp mode which is confused by this.
+    #
+    # We need to recreate these files for each test, as the compiler may
+    # overwrite some of them when testing with obscure command lines.
+    # This happens at least with the AIX C compiler.
+    : > sub/conftest.c
+    for i in 1 2 3 4 5 6; do
+      echo '#include "conftst'$i'.h"' >> sub/conftest.c
+      # Using ": > sub/conftst$i.h" creates only sub/conftst1.h with
+      # Solaris 10 /bin/sh.
+      echo '/* dummy */' > sub/conftst$i.h
+    done
+    echo "${am__include} ${am__quote}sub/conftest.Po${am__quote}" > confmf
+
+    # We check with '-c' and '-o' for the sake of the "dashmstdout"
+    # mode.  It turns out that the SunPro C++ compiler does not properly
+    # handle '-M -o', and we need to detect this.  Also, some Intel
+    # versions had trouble with output in subdirs.
+    am__obj=sub/conftest.${OBJEXT-o}
+    am__minus_obj="-o $am__obj"
+    case $depmode in
+    gcc)
+      # This depmode causes a compiler race in universal mode.
+      test "$am__universal" = false || continue
+      ;;
+    nosideeffect)
+      # After this tag, mechanisms are not by side-effect, so they'll
+      # only be used when explicitly requested.
+      if test "x$enable_dependency_tracking" = xyes; then
+	continue
+      else
+	break
+      fi
+      ;;
+    msvc7 | msvc7msys | msvisualcpp | msvcmsys)
+      # This compiler won't grok '-c -o', but also, the minuso test has
+      # not run yet.  These depmodes are late enough in the game, and
+      # so weak that their functioning should not be impacted.
+      am__obj=conftest.${OBJEXT-o}
+      am__minus_obj=
+      ;;
+    none) break ;;
+    esac
+    if depmode=$depmode \
+       source=sub/conftest.c object=$am__obj \
+       depfile=sub/conftest.Po tmpdepfile=sub/conftest.TPo \
+       $SHELL ./depcomp $depcc -c $am__minus_obj sub/conftest.c \
+         >/dev/null 2>conftest.err &&
+       grep sub/conftst1.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep sub/conftst6.h sub/conftest.Po > /dev/null 2>&1 &&
+       grep $am__obj sub/conftest.Po > /dev/null 2>&1 &&
+       ${MAKE-make} -s -f confmf > /dev/null 2>&1; then
+      # icc doesn't choke on unknown options, it will just issue warnings
+      # or remarks (even with -Werror).  So we grep stderr for any message
+      # that says an option was ignored or not supported.
+      # When given -MP, icc 7.0 and 7.1 complain thusly:
+      #   icc: Command line warning: ignoring option '-M'; no argument required
+      # The diagnosis changed in icc 8.0:
+      #   icc: Command line remark: option '-MP' not supported
+      if (grep 'ignoring option' conftest.err ||
+          grep 'not supported' conftest.err) >/dev/null 2>&1; then :; else
+        am_cv_CCAS_dependencies_compiler_type=$depmode
+        break
+      fi
+    fi
+  done
+
+  cd ..
+  rm -rf conftest.dir
+else
+  am_cv_CCAS_dependencies_compiler_type=none
+fi
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $am_cv_CCAS_dependencies_compiler_type" >&5
+printf "%s\n" "$am_cv_CCAS_dependencies_compiler_type" >&6; }
+CCASDEPMODE=depmode=$am_cv_CCAS_dependencies_compiler_type
+
+ if
+  test "x$enable_dependency_tracking" != xno \
+  && test "$am_cv_CCAS_dependencies_compiler_type" = gcc3; then
+  am__fastdepCCAS_TRUE=
+  am__fastdepCCAS_FALSE='#'
+else
+  am__fastdepCCAS_TRUE='#'
+  am__fastdepCCAS_FALSE=
+fi
+
+
+
+
+  # Make sure we can run config.sub.
+$SHELL "${ac_aux_dir}config.sub" sun4 >/dev/null 2>&1 ||
+  as_fn_error $? "cannot run $SHELL ${ac_aux_dir}config.sub" "$LINENO" 5
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking build system type" >&5
+printf %s "checking build system type... " >&6; }
+if test ${ac_cv_build+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_build_alias=$build_alias
+test "x$ac_build_alias" = x &&
+  ac_build_alias=`$SHELL "${ac_aux_dir}config.guess"`
+test "x$ac_build_alias" = x &&
+  as_fn_error $? "cannot guess build type; you must specify one" "$LINENO" 5
+ac_cv_build=`$SHELL "${ac_aux_dir}config.sub" $ac_build_alias` ||
+  as_fn_error $? "$SHELL ${ac_aux_dir}config.sub $ac_build_alias failed" "$LINENO" 5
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_build" >&5
+printf "%s\n" "$ac_cv_build" >&6; }
+case $ac_cv_build in
+*-*-*) ;;
+*) as_fn_error $? "invalid value of canonical build" "$LINENO" 5;;
+esac
+build=$ac_cv_build
+ac_save_IFS=$IFS; IFS='-'
+set x $ac_cv_build
+shift
+build_cpu=$1
+build_vendor=$2
+shift; shift
+# Remember, the first character of IFS is used to create $*,
+# except with old shells:
+build_os=$*
+IFS=$ac_save_IFS
+case $build_os in *\ *) build_os=`echo "$build_os" | sed 's/ /-/g'`;; esac
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking host system type" >&5
+printf %s "checking host system type... " >&6; }
+if test ${ac_cv_host+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test "x$host_alias" = x; then
+  ac_cv_host=$ac_cv_build
+else
+  ac_cv_host=`$SHELL "${ac_aux_dir}config.sub" $host_alias` ||
+    as_fn_error $? "$SHELL ${ac_aux_dir}config.sub $host_alias failed" "$LINENO" 5
+fi
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_host" >&5
+printf "%s\n" "$ac_cv_host" >&6; }
+case $ac_cv_host in
+*-*-*) ;;
+*) as_fn_error $? "invalid value of canonical host" "$LINENO" 5;;
+esac
+host=$ac_cv_host
+ac_save_IFS=$IFS; IFS='-'
+set x $ac_cv_host
+shift
+host_cpu=$1
+host_vendor=$2
+shift; shift
+# Remember, the first character of IFS is used to create $*,
+# except with old shells:
+host_os=$*
+IFS=$ac_save_IFS
+case $host_os in *\ *) host_os=`echo "$host_os" | sed 's/ /-/g'`;; esac
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for a sed that does not truncate output" >&5
+printf %s "checking for a sed that does not truncate output... " >&6; }
+if test ${ac_cv_path_SED+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)           ac_script=s/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb/
+     for ac_i in 1 2 3 4 5 6 7; do
+       ac_script="$ac_script$as_nl$ac_script"
+     done
+     echo "$ac_script" 2>/dev/null | sed 99q >conftest.sed
+     { ac_script=; unset ac_script;}
+     if test -z "$SED"; then
+  ac_path_SED_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_prog in sed gsed
+   do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_SED="$as_dir$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_SED" || continue
+# Check for GNU ac_path_SED and select it if it is found.
+  # Check for GNU $ac_path_SED
+case `"$ac_path_SED" --version 2>&1` in #(
+*GNU*)
+  ac_cv_path_SED="$ac_path_SED" ac_path_SED_found=:;;
+#(
+*)
+  ac_count=0
+  printf %s 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    printf "%s\n" '' >> "conftest.nl"
+    "$ac_path_SED" -f conftest.sed < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_SED_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_SED="$ac_path_SED"
+      ac_path_SED_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_SED_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_SED"; then
+    as_fn_error $? "no acceptable sed could be found in \$PATH" "$LINENO" 5
+  fi
+else
+  ac_cv_path_SED=$SED
+fi
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_SED" >&5
+printf "%s\n" "$ac_cv_path_SED" >&6; }
+ SED="$ac_cv_path_SED"
+  rm -f conftest.sed
+
+test -z "$SED" && SED=sed
+Xsed="$SED -e 1s/^X//"
+
+
+
+
+
+
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for grep that handles long lines and -e" >&5
+printf %s "checking for grep that handles long lines and -e... " >&6; }
+if test ${ac_cv_path_GREP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -z "$GREP"; then
+  ac_path_GREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_prog in grep ggrep
+   do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_GREP="$as_dir$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_GREP" || continue
+# Check for GNU ac_path_GREP and select it if it is found.
+  # Check for GNU $ac_path_GREP
+case `"$ac_path_GREP" --version 2>&1` in #(
+*GNU*)
+  ac_cv_path_GREP="$ac_path_GREP" ac_path_GREP_found=:;;
+#(
+*)
+  ac_count=0
+  printf %s 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    printf "%s\n" 'GREP' >> "conftest.nl"
+    "$ac_path_GREP" -e 'GREP$' -e '-(cannot match)-' < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_GREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_GREP="$ac_path_GREP"
+      ac_path_GREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_GREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_GREP"; then
+    as_fn_error $? "no acceptable grep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_GREP=$GREP
+fi
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_GREP" >&5
+printf "%s\n" "$ac_cv_path_GREP" >&6; }
+ GREP="$ac_cv_path_GREP"
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for egrep" >&5
+printf %s "checking for egrep... " >&6; }
+if test ${ac_cv_path_EGREP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if echo a | $GREP -E '(a|b)' >/dev/null 2>&1
+   then ac_cv_path_EGREP="$GREP -E"
+   else
+     if test -z "$EGREP"; then
+  ac_path_EGREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_prog in egrep
+   do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_EGREP="$as_dir$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_EGREP" || continue
+# Check for GNU ac_path_EGREP and select it if it is found.
+  # Check for GNU $ac_path_EGREP
+case `"$ac_path_EGREP" --version 2>&1` in #(
+*GNU*)
+  ac_cv_path_EGREP="$ac_path_EGREP" ac_path_EGREP_found=:;;
+#(
+*)
+  ac_count=0
+  printf %s 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    printf "%s\n" 'EGREP' >> "conftest.nl"
+    "$ac_path_EGREP" 'EGREP$' < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_EGREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_EGREP="$ac_path_EGREP"
+      ac_path_EGREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_EGREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_EGREP"; then
+    as_fn_error $? "no acceptable egrep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_EGREP=$EGREP
+fi
+
+   fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_EGREP" >&5
+printf "%s\n" "$ac_cv_path_EGREP" >&6; }
+ EGREP="$ac_cv_path_EGREP"
+
+         EGREP_TRADITIONAL=$EGREP
+ ac_cv_path_EGREP_TRADITIONAL=$EGREP
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for fgrep" >&5
+printf %s "checking for fgrep... " >&6; }
+if test ${ac_cv_path_FGREP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if echo 'ab*c' | $GREP -F 'ab*c' >/dev/null 2>&1
+   then ac_cv_path_FGREP="$GREP -F"
+   else
+     if test -z "$FGREP"; then
+  ac_path_FGREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_prog in fgrep
+   do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_FGREP="$as_dir$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_FGREP" || continue
+# Check for GNU ac_path_FGREP and select it if it is found.
+  # Check for GNU $ac_path_FGREP
+case `"$ac_path_FGREP" --version 2>&1` in #(
+*GNU*)
+  ac_cv_path_FGREP="$ac_path_FGREP" ac_path_FGREP_found=:;;
+#(
+*)
+  ac_count=0
+  printf %s 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    printf "%s\n" 'FGREP' >> "conftest.nl"
+    "$ac_path_FGREP" FGREP < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_FGREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_FGREP="$ac_path_FGREP"
+      ac_path_FGREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_FGREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_FGREP"; then
+    as_fn_error $? "no acceptable fgrep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_FGREP=$FGREP
+fi
+
+   fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_FGREP" >&5
+printf "%s\n" "$ac_cv_path_FGREP" >&6; }
+ FGREP="$ac_cv_path_FGREP"
+
+
+test -z "$GREP" && GREP=grep
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
+ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO
+ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO$ECHO
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking how to print strings" >&5
+printf %s "checking how to print strings... " >&6; }
+# Test print first, because it will be a builtin if present.
+if test "X`( print -r -- -n ) 2>/dev/null`" = X-n && \
+   test "X`print -r -- $ECHO 2>/dev/null`" = "X$ECHO"; then
+  ECHO='print -r --'
+elif test "X`printf %s $ECHO 2>/dev/null`" = "X$ECHO"; then
+  ECHO='printf %s\n'
+else
+  # Use this function as a fallback that always works.
+  func_fallback_echo ()
+  {
+    eval 'cat <<_LTECHO_EOF
+$1
+_LTECHO_EOF'
+  }
+  ECHO='func_fallback_echo'
+fi
+
+# func_echo_all arg...
+# Invoke $ECHO with all args, space-separated.
+func_echo_all ()
+{
+    $ECHO ""
+}
+
+case $ECHO in
+  printf*) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: printf" >&5
+printf "%s\n" "printf" >&6; } ;;
+  print*) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: print -r" >&5
+printf "%s\n" "print -r" >&6; } ;;
+  *) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: cat" >&5
+printf "%s\n" "cat" >&6; } ;;
+esac
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+# Check whether --with-gnu-ld was given.
+if test ${with_gnu_ld+y}
+then :
+  withval=$with_gnu_ld; test no = "$withval" || with_gnu_ld=yes
+else case e in #(
+  e) with_gnu_ld=no ;;
+esac
+fi
+
+ac_prog=ld
+if test yes = "$GCC"; then
+  # Check if gcc -print-prog-name=ld gives a path.
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for ld used by $CC" >&5
+printf %s "checking for ld used by $CC... " >&6; }
+  case $host in
+  *-*-mingw*)
+    # gcc leaves a trailing carriage return, which upsets mingw
+    ac_prog=`($CC -print-prog-name=ld) 2>&5 | tr -d '\015'` ;;
+  *)
+    ac_prog=`($CC -print-prog-name=ld) 2>&5` ;;
+  esac
+  case $ac_prog in
+    # Accept absolute paths.
+    [\\/]* | ?:[\\/]*)
+      re_direlt='/[^/][^/]*/\.\./'
+      # Canonicalize the pathname of ld
+      ac_prog=`$ECHO "$ac_prog"| $SED 's%\\\\%/%g'`
+      while $ECHO "$ac_prog" | $GREP "$re_direlt" > /dev/null 2>&1; do
+	ac_prog=`$ECHO $ac_prog| $SED "s%$re_direlt%/%"`
+      done
+      test -z "$LD" && LD=$ac_prog
+      ;;
+  "")
+    # If it fails, then pretend we aren't using GCC.
+    ac_prog=ld
+    ;;
+  *)
+    # If it is relative, then search for the first ld in PATH.
+    with_gnu_ld=unknown
+    ;;
+  esac
+elif test yes = "$with_gnu_ld"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for GNU ld" >&5
+printf %s "checking for GNU ld... " >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for non-GNU ld" >&5
+printf %s "checking for non-GNU ld... " >&6; }
+fi
+if test ${lt_cv_path_LD+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -z "$LD"; then
+  lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+  for ac_dir in $PATH; do
+    IFS=$lt_save_ifs
+    test -z "$ac_dir" && ac_dir=.
+    if test -f "$ac_dir/$ac_prog" || test -f "$ac_dir/$ac_prog$ac_exeext"; then
+      lt_cv_path_LD=$ac_dir/$ac_prog
+      # Check to see if the program is GNU ld.  I'd rather use --version,
+      # but apparently some variants of GNU ld only accept -v.
+      # Break only if it was the GNU/non-GNU ld that we prefer.
+      case `"$lt_cv_path_LD" -v 2>&1 </dev/null` in
+      *GNU* | *'with BFD'*)
+	test no != "$with_gnu_ld" && break
+	;;
+      *)
+	test yes != "$with_gnu_ld" && break
+	;;
+      esac
+    fi
+  done
+  IFS=$lt_save_ifs
+else
+  lt_cv_path_LD=$LD # Let the user override the test with a path.
+fi ;;
+esac
+fi
+
+LD=$lt_cv_path_LD
+if test -n "$LD"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $LD" >&5
+printf "%s\n" "$LD" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+test -z "$LD" && as_fn_error $? "no acceptable ld found in \$PATH" "$LINENO" 5
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if the linker ($LD) is GNU ld" >&5
+printf %s "checking if the linker ($LD) is GNU ld... " >&6; }
+if test ${lt_cv_prog_gnu_ld+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) # I'd rather use --version here, but apparently some GNU lds only accept -v.
+case `$LD -v 2>&1 </dev/null` in
+*GNU* | *'with BFD'*)
+  lt_cv_prog_gnu_ld=yes
+  ;;
+*)
+  lt_cv_prog_gnu_ld=no
+  ;;
+esac ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_gnu_ld" >&5
+printf "%s\n" "$lt_cv_prog_gnu_ld" >&6; }
+with_gnu_ld=$lt_cv_prog_gnu_ld
+
+
+
+
+
+
+
+
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking how to run the C preprocessor" >&5
+printf %s "checking how to run the C preprocessor... " >&6; }
+# On Suns, sometimes $CPP names a directory.
+if test -n "$CPP" && test -d "$CPP"; then
+  CPP=
+fi
+if test -z "$CPP"; then
+  if test ${ac_cv_prog_CPP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)     # Double quotes because $CC needs to be expanded
+    for CPP in "$CC -E" "$CC -E -traditional-cpp" cpp /lib/cpp
+    do
+      ac_preproc_ok=false
+for ac_c_preproc_warn_flag in '' yes
+do
+  # Use a header file that comes with gcc, so configuring glibc
+  # with a fresh cross-compiler works.
+  # On the NeXT, cc -E runs the code through the compiler's parser,
+  # not just through cpp. "Syntax error" is here to catch this case.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <limits.h>
+		     Syntax error
+_ACEOF
+if ac_fn_c_try_cpp "$LINENO"
+then :
+
+else case e in #(
+  e) # Broken: fails on valid input.
+continue ;;
+esac
+fi
+rm -f conftest.err conftest.i conftest.$ac_ext
+
+  # OK, works on sane cases.  Now check whether nonexistent headers
+  # can be detected and how.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <ac_nonexistent.h>
+_ACEOF
+if ac_fn_c_try_cpp "$LINENO"
+then :
+  # Broken: success on invalid input.
+continue
+else case e in #(
+  e) # Passes both tests.
+ac_preproc_ok=:
+break ;;
+esac
+fi
+rm -f conftest.err conftest.i conftest.$ac_ext
+
+done
+# Because of 'break', _AC_PREPROC_IFELSE's cleaning code was skipped.
+rm -f conftest.i conftest.err conftest.$ac_ext
+if $ac_preproc_ok
+then :
+  break
+fi
+
+    done
+    ac_cv_prog_CPP=$CPP
+   ;;
+esac
+fi
+  CPP=$ac_cv_prog_CPP
+else
+  ac_cv_prog_CPP=$CPP
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CPP" >&5
+printf "%s\n" "$CPP" >&6; }
+ac_preproc_ok=false
+for ac_c_preproc_warn_flag in '' yes
+do
+  # Use a header file that comes with gcc, so configuring glibc
+  # with a fresh cross-compiler works.
+  # On the NeXT, cc -E runs the code through the compiler's parser,
+  # not just through cpp. "Syntax error" is here to catch this case.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <limits.h>
+		     Syntax error
+_ACEOF
+if ac_fn_c_try_cpp "$LINENO"
+then :
+
+else case e in #(
+  e) # Broken: fails on valid input.
+continue ;;
+esac
+fi
+rm -f conftest.err conftest.i conftest.$ac_ext
+
+  # OK, works on sane cases.  Now check whether nonexistent headers
+  # can be detected and how.
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <ac_nonexistent.h>
+_ACEOF
+if ac_fn_c_try_cpp "$LINENO"
+then :
+  # Broken: success on invalid input.
+continue
+else case e in #(
+  e) # Passes both tests.
+ac_preproc_ok=:
+break ;;
+esac
+fi
+rm -f conftest.err conftest.i conftest.$ac_ext
+
+done
+# Because of 'break', _AC_PREPROC_IFELSE's cleaning code was skipped.
+rm -f conftest.i conftest.err conftest.$ac_ext
+if $ac_preproc_ok
+then :
+
+else case e in #(
+  e) { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+as_fn_error $? "C preprocessor \"$CPP\" fails sanity check
+See 'config.log' for more details" "$LINENO" 5; } ;;
+esac
+fi
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+for ac_prog in gawk mawk nawk awk
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_AWK+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$AWK"; then
+  ac_cv_prog_AWK="$AWK" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AWK="$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+AWK=$ac_cv_prog_AWK
+if test -n "$AWK"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $AWK" >&5
+printf "%s\n" "$AWK" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  test -n "$AWK" && break
+done
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether ln -s works" >&5
+printf %s "checking whether ln -s works... " >&6; }
+LN_S=$as_ln_s
+if test "$LN_S" = "ln -s"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no, using $LN_S" >&5
+printf "%s\n" "no, using $LN_S" >&6; }
+fi
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether ${MAKE-make} sets \$(MAKE)" >&5
+printf %s "checking whether ${MAKE-make} sets \$(MAKE)... " >&6; }
+set x ${MAKE-make}
+ac_make=`printf "%s\n" "$2" | sed 's/+/p/g; s/[^a-zA-Z0-9_]/_/g'`
+if eval test \${ac_cv_prog_make_${ac_make}_set+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat >conftest.make <<\_ACEOF
+SHELL = /bin/sh
+all:
+	@echo '@@@%%%=$(MAKE)=@@@%%%'
+_ACEOF
+# GNU make sometimes prints "make[1]: Entering ...", which would confuse us.
+case `${MAKE-make} -f conftest.make 2>/dev/null` in
+  *@@@%%%=?*=@@@%%%*)
+    eval ac_cv_prog_make_${ac_make}_set=yes;;
+  *)
+    eval ac_cv_prog_make_${ac_make}_set=no;;
+esac
+rm -f conftest.make ;;
+esac
+fi
+if eval test \$ac_cv_prog_make_${ac_make}_set = yes; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+  SET_MAKE=
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+  SET_MAKE="MAKE=${MAKE-make}"
+fi
+
+
+case `pwd` in
+  *\ * | *\	*)
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: Libtool does not cope well with whitespace in \`pwd\`" >&5
+printf "%s\n" "$as_me: WARNING: Libtool does not cope well with whitespace in \`pwd\`" >&2;} ;;
+esac
+
+
+
+macro_version='2.4.7'
+macro_revision='2.4.7'
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ltmain=$ac_aux_dir/ltmain.sh
+
+# Backslashify metacharacters that are still active within
+# double-quoted strings.
+sed_quote_subst='s/\(["`$\\]\)/\\\1/g'
+
+# Same as above, but do not quote variable references.
+double_quote_subst='s/\(["`\\]\)/\\\1/g'
+
+# Sed substitution to delay expansion of an escaped shell variable in a
+# double_quote_subst'ed string.
+delay_variable_subst='s/\\\\\\\\\\\$/\\\\\\$/g'
+
+# Sed substitution to delay expansion of an escaped single quote.
+delay_single_quote_subst='s/'\''/'\'\\\\\\\'\''/g'
+
+# Sed substitution to avoid accidental globbing in evaled expressions
+no_glob_subst='s/\*/\\\*/g'
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for BSD- or MS-compatible name lister (nm)" >&5
+printf %s "checking for BSD- or MS-compatible name lister (nm)... " >&6; }
+if test ${lt_cv_path_NM+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$NM"; then
+  # Let the user override the test.
+  lt_cv_path_NM=$NM
+else
+  lt_nm_to_check=${ac_tool_prefix}nm
+  if test -n "$ac_tool_prefix" && test "$build" = "$host"; then
+    lt_nm_to_check="$lt_nm_to_check nm"
+  fi
+  for lt_tmp_nm in $lt_nm_to_check; do
+    lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+    for ac_dir in $PATH /usr/ccs/bin/elf /usr/ccs/bin /usr/ucb /bin; do
+      IFS=$lt_save_ifs
+      test -z "$ac_dir" && ac_dir=.
+      tmp_nm=$ac_dir/$lt_tmp_nm
+      if test -f "$tmp_nm" || test -f "$tmp_nm$ac_exeext"; then
+	# Check to see if the nm accepts a BSD-compat flag.
+	# Adding the 'sed 1q' prevents false positives on HP-UX, which says:
+	#   nm: unknown option "B" ignored
+	# Tru64's nm complains that /dev/null is an invalid object file
+	# MSYS converts /dev/null to NUL, MinGW nm treats NUL as empty
+	case $build_os in
+	mingw*) lt_bad_file=conftest.nm/nofile ;;
+	*) lt_bad_file=/dev/null ;;
+	esac
+	case `"$tmp_nm" -B $lt_bad_file 2>&1 | $SED '1q'` in
+	*$lt_bad_file* | *'Invalid file or object type'*)
+	  lt_cv_path_NM="$tmp_nm -B"
+	  break 2
+	  ;;
+	*)
+	  case `"$tmp_nm" -p /dev/null 2>&1 | $SED '1q'` in
+	  */dev/null*)
+	    lt_cv_path_NM="$tmp_nm -p"
+	    break 2
+	    ;;
+	  *)
+	    lt_cv_path_NM=${lt_cv_path_NM="$tmp_nm"} # keep the first match, but
+	    continue # so that we can try to find one that supports BSD flags
+	    ;;
+	  esac
+	  ;;
+	esac
+      fi
+    done
+    IFS=$lt_save_ifs
+  done
+  : ${lt_cv_path_NM=no}
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_path_NM" >&5
+printf "%s\n" "$lt_cv_path_NM" >&6; }
+if test no != "$lt_cv_path_NM"; then
+  NM=$lt_cv_path_NM
+else
+  # Didn't find any BSD compatible name lister, look for dumpbin.
+  if test -n "$DUMPBIN"; then :
+    # Let the user override the test.
+  else
+    if test -n "$ac_tool_prefix"; then
+  for ac_prog in dumpbin "link -dump"
+  do
+    # Extract the first word of "$ac_tool_prefix$ac_prog", so it can be a program name with args.
+set dummy $ac_tool_prefix$ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_DUMPBIN+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$DUMPBIN"; then
+  ac_cv_prog_DUMPBIN="$DUMPBIN" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_DUMPBIN="$ac_tool_prefix$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+DUMPBIN=$ac_cv_prog_DUMPBIN
+if test -n "$DUMPBIN"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $DUMPBIN" >&5
+printf "%s\n" "$DUMPBIN" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+    test -n "$DUMPBIN" && break
+  done
+fi
+if test -z "$DUMPBIN"; then
+  ac_ct_DUMPBIN=$DUMPBIN
+  for ac_prog in dumpbin "link -dump"
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_DUMPBIN+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_DUMPBIN"; then
+  ac_cv_prog_ac_ct_DUMPBIN="$ac_ct_DUMPBIN" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_DUMPBIN="$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_DUMPBIN=$ac_cv_prog_ac_ct_DUMPBIN
+if test -n "$ac_ct_DUMPBIN"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_DUMPBIN" >&5
+printf "%s\n" "$ac_ct_DUMPBIN" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  test -n "$ac_ct_DUMPBIN" && break
+done
+
+  if test "x$ac_ct_DUMPBIN" = x; then
+    DUMPBIN=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    DUMPBIN=$ac_ct_DUMPBIN
+  fi
+fi
+
+    case `$DUMPBIN -symbols -headers /dev/null 2>&1 | $SED '1q'` in
+    *COFF*)
+      DUMPBIN="$DUMPBIN -symbols -headers"
+      ;;
+    *)
+      DUMPBIN=:
+      ;;
+    esac
+  fi
+
+  if test : != "$DUMPBIN"; then
+    NM=$DUMPBIN
+  fi
+fi
+test -z "$NM" && NM=nm
+
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking the name lister ($NM) interface" >&5
+printf %s "checking the name lister ($NM) interface... " >&6; }
+if test ${lt_cv_nm_interface+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_nm_interface="BSD nm"
+  echo "int some_variable = 0;" > conftest.$ac_ext
+  (eval echo "\"\$as_me:$LINENO: $ac_compile\"" >&5)
+  (eval "$ac_compile" 2>conftest.err)
+  cat conftest.err >&5
+  (eval echo "\"\$as_me:$LINENO: $NM \\\"conftest.$ac_objext\\\"\"" >&5)
+  (eval "$NM \"conftest.$ac_objext\"" 2>conftest.err > conftest.out)
+  cat conftest.err >&5
+  (eval echo "\"\$as_me:$LINENO: output\"" >&5)
+  cat conftest.out >&5
+  if $GREP 'External.*some_variable' conftest.out > /dev/null; then
+    lt_cv_nm_interface="MS dumpbin"
+  fi
+  rm -f conftest* ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_nm_interface" >&5
+printf "%s\n" "$lt_cv_nm_interface" >&6; }
+
+# find the maximum length of command line arguments
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking the maximum length of command line arguments" >&5
+printf %s "checking the maximum length of command line arguments... " >&6; }
+if test ${lt_cv_sys_max_cmd_len+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)   i=0
+  teststring=ABCD
+
+  case $build_os in
+  msdosdjgpp*)
+    # On DJGPP, this test can blow up pretty badly due to problems in libc
+    # (any single argument exceeding 2000 bytes causes a buffer overrun
+    # during glob expansion).  Even if it were fixed, the result of this
+    # check would be larger than it should be.
+    lt_cv_sys_max_cmd_len=12288;    # 12K is about right
+    ;;
+
+  gnu*)
+    # Under GNU Hurd, this test is not required because there is
+    # no limit to the length of command line arguments.
+    # Libtool will interpret -1 as no limit whatsoever
+    lt_cv_sys_max_cmd_len=-1;
+    ;;
+
+  cygwin* | mingw* | cegcc*)
+    # On Win9x/ME, this test blows up -- it succeeds, but takes
+    # about 5 minutes as the teststring grows exponentially.
+    # Worse, since 9x/ME are not pre-emptively multitasking,
+    # you end up with a "frozen" computer, even though with patience
+    # the test eventually succeeds (with a max line length of 256k).
+    # Instead, let's just punt: use the minimum linelength reported by
+    # all of the supported platforms: 8192 (on NT/2K/XP).
+    lt_cv_sys_max_cmd_len=8192;
+    ;;
+
+  mint*)
+    # On MiNT this can take a long time and run out of memory.
+    lt_cv_sys_max_cmd_len=8192;
+    ;;
+
+  amigaos*)
+    # On AmigaOS with pdksh, this test takes hours, literally.
+    # So we just punt and use a minimum line length of 8192.
+    lt_cv_sys_max_cmd_len=8192;
+    ;;
+
+  bitrig* | darwin* | dragonfly* | freebsd* | midnightbsd* | netbsd* | openbsd*)
+    # This has been around since 386BSD, at least.  Likely further.
+    if test -x /sbin/sysctl; then
+      lt_cv_sys_max_cmd_len=`/sbin/sysctl -n kern.argmax`
+    elif test -x /usr/sbin/sysctl; then
+      lt_cv_sys_max_cmd_len=`/usr/sbin/sysctl -n kern.argmax`
+    else
+      lt_cv_sys_max_cmd_len=65536	# usable default for all BSDs
+    fi
+    # And add a safety zone
+    lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \/ 4`
+    lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \* 3`
+    ;;
+
+  interix*)
+    # We know the value 262144 and hardcode it with a safety zone (like BSD)
+    lt_cv_sys_max_cmd_len=196608
+    ;;
+
+  os2*)
+    # The test takes a long time on OS/2.
+    lt_cv_sys_max_cmd_len=8192
+    ;;
+
+  osf*)
+    # Dr. Hans Ekkehard Plesser reports seeing a kernel panic running configure
+    # due to this test when exec_disable_arg_limit is 1 on Tru64. It is not
+    # nice to cause kernel panics so lets avoid the loop below.
+    # First set a reasonable default.
+    lt_cv_sys_max_cmd_len=16384
+    #
+    if test -x /sbin/sysconfig; then
+      case `/sbin/sysconfig -q proc exec_disable_arg_limit` in
+        *1*) lt_cv_sys_max_cmd_len=-1 ;;
+      esac
+    fi
+    ;;
+  sco3.2v5*)
+    lt_cv_sys_max_cmd_len=102400
+    ;;
+  sysv5* | sco5v6* | sysv4.2uw2*)
+    kargmax=`grep ARG_MAX /etc/conf/cf.d/stune 2>/dev/null`
+    if test -n "$kargmax"; then
+      lt_cv_sys_max_cmd_len=`echo $kargmax | $SED 's/.*[	 ]//'`
+    else
+      lt_cv_sys_max_cmd_len=32768
+    fi
+    ;;
+  *)
+    lt_cv_sys_max_cmd_len=`(getconf ARG_MAX) 2> /dev/null`
+    if test -n "$lt_cv_sys_max_cmd_len" && \
+       test undefined != "$lt_cv_sys_max_cmd_len"; then
+      lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \/ 4`
+      lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \* 3`
+    else
+      # Make teststring a little bigger before we do anything with it.
+      # a 1K string should be a reasonable start.
+      for i in 1 2 3 4 5 6 7 8; do
+        teststring=$teststring$teststring
+      done
+      SHELL=${SHELL-${CONFIG_SHELL-/bin/sh}}
+      # If test is not a shell built-in, we'll probably end up computing a
+      # maximum length that is only half of the actual maximum length, but
+      # we can't tell.
+      while { test X`env echo "$teststring$teststring" 2>/dev/null` \
+	         = "X$teststring$teststring"; } >/dev/null 2>&1 &&
+	      test 17 != "$i" # 1/2 MB should be enough
+      do
+        i=`expr $i + 1`
+        teststring=$teststring$teststring
+      done
+      # Only check the string length outside the loop.
+      lt_cv_sys_max_cmd_len=`expr "X$teststring" : ".*" 2>&1`
+      teststring=
+      # Add a significant safety factor because C++ compilers can tack on
+      # massive amounts of additional arguments before passing them to the
+      # linker.  It appears as though 1/2 is a usable value.
+      lt_cv_sys_max_cmd_len=`expr $lt_cv_sys_max_cmd_len \/ 2`
+    fi
+    ;;
+  esac
+ ;;
+esac
+fi
+
+if test -n "$lt_cv_sys_max_cmd_len"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_sys_max_cmd_len" >&5
+printf "%s\n" "$lt_cv_sys_max_cmd_len" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: none" >&5
+printf "%s\n" "none" >&6; }
+fi
+max_cmd_len=$lt_cv_sys_max_cmd_len
+
+
+
+
+
+
+: ${CP="cp -f"}
+: ${MV="mv -f"}
+: ${RM="rm -f"}
+
+if ( (MAIL=60; unset MAIL) || exit) >/dev/null 2>&1; then
+  lt_unset=unset
+else
+  lt_unset=false
+fi
+
+
+
+
+
+# test EBCDIC or ASCII
+case `echo X|tr X '\101'` in
+ A) # ASCII based system
+    # \n is not interpreted correctly by Solaris 8 /usr/ucb/tr
+  lt_SP2NL='tr \040 \012'
+  lt_NL2SP='tr \015\012 \040\040'
+  ;;
+ *) # EBCDIC based system
+  lt_SP2NL='tr \100 \n'
+  lt_NL2SP='tr \r\n \100\100'
+  ;;
+esac
+
+
+
+
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking how to convert $build file names to $host format" >&5
+printf %s "checking how to convert $build file names to $host format... " >&6; }
+if test ${lt_cv_to_host_file_cmd+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) case $host in
+  *-*-mingw* )
+    case $build in
+      *-*-mingw* ) # actually msys
+        lt_cv_to_host_file_cmd=func_convert_file_msys_to_w32
+        ;;
+      *-*-cygwin* )
+        lt_cv_to_host_file_cmd=func_convert_file_cygwin_to_w32
+        ;;
+      * ) # otherwise, assume *nix
+        lt_cv_to_host_file_cmd=func_convert_file_nix_to_w32
+        ;;
+    esac
+    ;;
+  *-*-cygwin* )
+    case $build in
+      *-*-mingw* ) # actually msys
+        lt_cv_to_host_file_cmd=func_convert_file_msys_to_cygwin
+        ;;
+      *-*-cygwin* )
+        lt_cv_to_host_file_cmd=func_convert_file_noop
+        ;;
+      * ) # otherwise, assume *nix
+        lt_cv_to_host_file_cmd=func_convert_file_nix_to_cygwin
+        ;;
+    esac
+    ;;
+  * ) # unhandled hosts (and "normal" native builds)
+    lt_cv_to_host_file_cmd=func_convert_file_noop
+    ;;
+esac
+ ;;
+esac
+fi
+
+to_host_file_cmd=$lt_cv_to_host_file_cmd
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_to_host_file_cmd" >&5
+printf "%s\n" "$lt_cv_to_host_file_cmd" >&6; }
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking how to convert $build file names to toolchain format" >&5
+printf %s "checking how to convert $build file names to toolchain format... " >&6; }
+if test ${lt_cv_to_tool_file_cmd+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) #assume ordinary cross tools, or native build.
+lt_cv_to_tool_file_cmd=func_convert_file_noop
+case $host in
+  *-*-mingw* )
+    case $build in
+      *-*-mingw* ) # actually msys
+        lt_cv_to_tool_file_cmd=func_convert_file_msys_to_w32
+        ;;
+    esac
+    ;;
+esac
+ ;;
+esac
+fi
+
+to_tool_file_cmd=$lt_cv_to_tool_file_cmd
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_to_tool_file_cmd" >&5
+printf "%s\n" "$lt_cv_to_tool_file_cmd" >&6; }
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $LD option to reload object files" >&5
+printf %s "checking for $LD option to reload object files... " >&6; }
+if test ${lt_cv_ld_reload_flag+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_ld_reload_flag='-r' ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_ld_reload_flag" >&5
+printf "%s\n" "$lt_cv_ld_reload_flag" >&6; }
+reload_flag=$lt_cv_ld_reload_flag
+case $reload_flag in
+"" | " "*) ;;
+*) reload_flag=" $reload_flag" ;;
+esac
+reload_cmds='$LD$reload_flag -o $output$reload_objs'
+case $host_os in
+  cygwin* | mingw* | pw32* | cegcc*)
+    if test yes != "$GCC"; then
+      reload_cmds=false
+    fi
+    ;;
+  darwin*)
+    if test yes = "$GCC"; then
+      reload_cmds='$LTCC $LTCFLAGS -nostdlib $wl-r -o $output$reload_objs'
+    else
+      reload_cmds='$LD$reload_flag -o $output$reload_objs'
+    fi
+    ;;
+esac
+
+
+
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}file", so it can be a program name with args.
+set dummy ${ac_tool_prefix}file; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_FILECMD+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$FILECMD"; then
+  ac_cv_prog_FILECMD="$FILECMD" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_FILECMD="${ac_tool_prefix}file"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+FILECMD=$ac_cv_prog_FILECMD
+if test -n "$FILECMD"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $FILECMD" >&5
+printf "%s\n" "$FILECMD" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_FILECMD"; then
+  ac_ct_FILECMD=$FILECMD
+  # Extract the first word of "file", so it can be a program name with args.
+set dummy file; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_FILECMD+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_FILECMD"; then
+  ac_cv_prog_ac_ct_FILECMD="$ac_ct_FILECMD" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_FILECMD="file"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_FILECMD=$ac_cv_prog_ac_ct_FILECMD
+if test -n "$ac_ct_FILECMD"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_FILECMD" >&5
+printf "%s\n" "$ac_ct_FILECMD" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_FILECMD" = x; then
+    FILECMD=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    FILECMD=$ac_ct_FILECMD
+  fi
+else
+  FILECMD="$ac_cv_prog_FILECMD"
+fi
+
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}objdump", so it can be a program name with args.
+set dummy ${ac_tool_prefix}objdump; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_OBJDUMP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$OBJDUMP"; then
+  ac_cv_prog_OBJDUMP="$OBJDUMP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_OBJDUMP="${ac_tool_prefix}objdump"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+OBJDUMP=$ac_cv_prog_OBJDUMP
+if test -n "$OBJDUMP"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $OBJDUMP" >&5
+printf "%s\n" "$OBJDUMP" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_OBJDUMP"; then
+  ac_ct_OBJDUMP=$OBJDUMP
+  # Extract the first word of "objdump", so it can be a program name with args.
+set dummy objdump; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_OBJDUMP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_OBJDUMP"; then
+  ac_cv_prog_ac_ct_OBJDUMP="$ac_ct_OBJDUMP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_OBJDUMP="objdump"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_OBJDUMP=$ac_cv_prog_ac_ct_OBJDUMP
+if test -n "$ac_ct_OBJDUMP"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_OBJDUMP" >&5
+printf "%s\n" "$ac_ct_OBJDUMP" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_OBJDUMP" = x; then
+    OBJDUMP="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    OBJDUMP=$ac_ct_OBJDUMP
+  fi
+else
+  OBJDUMP="$ac_cv_prog_OBJDUMP"
+fi
+
+test -z "$OBJDUMP" && OBJDUMP=objdump
+
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking how to recognize dependent libraries" >&5
+printf %s "checking how to recognize dependent libraries... " >&6; }
+if test ${lt_cv_deplibs_check_method+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_file_magic_cmd='$MAGIC_CMD'
+lt_cv_file_magic_test_file=
+lt_cv_deplibs_check_method='unknown'
+# Need to set the preceding variable on all platforms that support
+# interlibrary dependencies.
+# 'none' -- dependencies not supported.
+# 'unknown' -- same as none, but documents that we really don't know.
+# 'pass_all' -- all dependencies passed with no checks.
+# 'test_compile' -- check by making test program.
+# 'file_magic [[regex]]' -- check by looking for files in library path
+# that responds to the $file_magic_cmd with a given extended regex.
+# If you have 'file' or equivalent on your system and you're not sure
+# whether 'pass_all' will *always* work, you probably want this one.
+
+case $host_os in
+aix[4-9]*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+beos*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+bsdi[45]*)
+  lt_cv_deplibs_check_method='file_magic ELF [0-9][0-9]*-bit [ML]SB (shared object|dynamic lib)'
+  lt_cv_file_magic_cmd='$FILECMD -L'
+  lt_cv_file_magic_test_file=/shlib/libc.so
+  ;;
+
+cygwin*)
+  # func_win32_libid is a shell function defined in ltmain.sh
+  lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
+  lt_cv_file_magic_cmd='func_win32_libid'
+  ;;
+
+mingw* | pw32*)
+  # Base MSYS/MinGW do not provide the 'file' command needed by
+  # func_win32_libid shell function, so use a weaker test based on 'objdump',
+  # unless we find 'file', for example because we are cross-compiling.
+  if ( file / ) >/dev/null 2>&1; then
+    lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
+    lt_cv_file_magic_cmd='func_win32_libid'
+  else
+    # Keep this pattern in sync with the one in func_win32_libid.
+    lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)'
+    lt_cv_file_magic_cmd='$OBJDUMP -f'
+  fi
+  ;;
+
+cegcc*)
+  # use the weaker test based on 'objdump'. See mingw*.
+  lt_cv_deplibs_check_method='file_magic file format pe-arm-.*little(.*architecture: arm)?'
+  lt_cv_file_magic_cmd='$OBJDUMP -f'
+  ;;
+
+darwin* | rhapsody*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+freebsd* | dragonfly* | midnightbsd*)
+  if echo __ELF__ | $CC -E - | $GREP __ELF__ > /dev/null; then
+    case $host_cpu in
+    i*86 )
+      # Not sure whether the presence of OpenBSD here was a mistake.
+      # Let's accept both of them until this is cleared up.
+      lt_cv_deplibs_check_method='file_magic (FreeBSD|OpenBSD|DragonFly)/i[3-9]86 (compact )?demand paged shared library'
+      lt_cv_file_magic_cmd=$FILECMD
+      lt_cv_file_magic_test_file=`echo /usr/lib/libc.so.*`
+      ;;
+    esac
+  else
+    lt_cv_deplibs_check_method=pass_all
+  fi
+  ;;
+
+haiku*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+hpux10.20* | hpux11*)
+  lt_cv_file_magic_cmd=$FILECMD
+  case $host_cpu in
+  ia64*)
+    lt_cv_deplibs_check_method='file_magic (s[0-9][0-9][0-9]|ELF-[0-9][0-9]) shared object file - IA64'
+    lt_cv_file_magic_test_file=/usr/lib/hpux32/libc.so
+    ;;
+  hppa*64*)
+    lt_cv_deplibs_check_method='file_magic (s[0-9][0-9][0-9]|ELF[ -][0-9][0-9])(-bit)?( [LM]SB)? shared object( file)?[, -]* PA-RISC [0-9]\.[0-9]'
+    lt_cv_file_magic_test_file=/usr/lib/pa20_64/libc.sl
+    ;;
+  *)
+    lt_cv_deplibs_check_method='file_magic (s[0-9][0-9][0-9]|PA-RISC[0-9]\.[0-9]) shared library'
+    lt_cv_file_magic_test_file=/usr/lib/libc.sl
+    ;;
+  esac
+  ;;
+
+interix[3-9]*)
+  # PIC code is broken on Interix 3.x, that's why |\.a not |_pic\.a here
+  lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so|\.a)$'
+  ;;
+
+irix5* | irix6* | nonstopux*)
+  case $LD in
+  *-32|*"-32 ") libmagic=32-bit;;
+  *-n32|*"-n32 ") libmagic=N32;;
+  *-64|*"-64 ") libmagic=64-bit;;
+  *) libmagic=never-match;;
+  esac
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+# This must be glibc/ELF.
+linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+netbsd*)
+  if echo __ELF__ | $CC -E - | $GREP __ELF__ > /dev/null; then
+    lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so\.[0-9]+\.[0-9]+|_pic\.a)$'
+  else
+    lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so|_pic\.a)$'
+  fi
+  ;;
+
+newos6*)
+  lt_cv_deplibs_check_method='file_magic ELF [0-9][0-9]*-bit [ML]SB (executable|dynamic lib)'
+  lt_cv_file_magic_cmd=$FILECMD
+  lt_cv_file_magic_test_file=/usr/lib/libnls.so
+  ;;
+
+*nto* | *qnx*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+openbsd* | bitrig*)
+  if test -z "`echo __ELF__ | $CC -E - | $GREP __ELF__`"; then
+    lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so\.[0-9]+\.[0-9]+|\.so|_pic\.a)$'
+  else
+    lt_cv_deplibs_check_method='match_pattern /lib[^/]+(\.so\.[0-9]+\.[0-9]+|_pic\.a)$'
+  fi
+  ;;
+
+osf3* | osf4* | osf5*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+rdos*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+solaris*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX* | sysv4*uw2*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+
+sysv4 | sysv4.3*)
+  case $host_vendor in
+  motorola)
+    lt_cv_deplibs_check_method='file_magic ELF [0-9][0-9]*-bit [ML]SB (shared object|dynamic lib) M[0-9][0-9]* Version [0-9]'
+    lt_cv_file_magic_test_file=`echo /usr/lib/libc.so*`
+    ;;
+  ncr)
+    lt_cv_deplibs_check_method=pass_all
+    ;;
+  sequent)
+    lt_cv_file_magic_cmd='/bin/file'
+    lt_cv_deplibs_check_method='file_magic ELF [0-9][0-9]*-bit [LM]SB (shared object|dynamic lib )'
+    ;;
+  sni)
+    lt_cv_file_magic_cmd='/bin/file'
+    lt_cv_deplibs_check_method="file_magic ELF [0-9][0-9]*-bit [LM]SB dynamic lib"
+    lt_cv_file_magic_test_file=/lib/libc.so
+    ;;
+  siemens)
+    lt_cv_deplibs_check_method=pass_all
+    ;;
+  pc)
+    lt_cv_deplibs_check_method=pass_all
+    ;;
+  esac
+  ;;
+
+tpf*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+os2*)
+  lt_cv_deplibs_check_method=pass_all
+  ;;
+esac
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_deplibs_check_method" >&5
+printf "%s\n" "$lt_cv_deplibs_check_method" >&6; }
+
+file_magic_glob=
+want_nocaseglob=no
+if test "$build" = "$host"; then
+  case $host_os in
+  mingw* | pw32*)
+    if ( shopt | grep nocaseglob ) >/dev/null 2>&1; then
+      want_nocaseglob=yes
+    else
+      file_magic_glob=`echo aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ | $SED -e "s/\(..\)/s\/[\1]\/[\1]\/g;/g"`
+    fi
+    ;;
+  esac
+fi
+
+file_magic_cmd=$lt_cv_file_magic_cmd
+deplibs_check_method=$lt_cv_deplibs_check_method
+test -z "$deplibs_check_method" && deplibs_check_method=unknown
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}dlltool", so it can be a program name with args.
+set dummy ${ac_tool_prefix}dlltool; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_DLLTOOL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$DLLTOOL"; then
+  ac_cv_prog_DLLTOOL="$DLLTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_DLLTOOL="${ac_tool_prefix}dlltool"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+DLLTOOL=$ac_cv_prog_DLLTOOL
+if test -n "$DLLTOOL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $DLLTOOL" >&5
+printf "%s\n" "$DLLTOOL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_DLLTOOL"; then
+  ac_ct_DLLTOOL=$DLLTOOL
+  # Extract the first word of "dlltool", so it can be a program name with args.
+set dummy dlltool; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_DLLTOOL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_DLLTOOL"; then
+  ac_cv_prog_ac_ct_DLLTOOL="$ac_ct_DLLTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_DLLTOOL="dlltool"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_DLLTOOL=$ac_cv_prog_ac_ct_DLLTOOL
+if test -n "$ac_ct_DLLTOOL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_DLLTOOL" >&5
+printf "%s\n" "$ac_ct_DLLTOOL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_DLLTOOL" = x; then
+    DLLTOOL="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    DLLTOOL=$ac_ct_DLLTOOL
+  fi
+else
+  DLLTOOL="$ac_cv_prog_DLLTOOL"
+fi
+
+test -z "$DLLTOOL" && DLLTOOL=dlltool
+
+
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking how to associate runtime and link libraries" >&5
+printf %s "checking how to associate runtime and link libraries... " >&6; }
+if test ${lt_cv_sharedlib_from_linklib_cmd+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_sharedlib_from_linklib_cmd='unknown'
+
+case $host_os in
+cygwin* | mingw* | pw32* | cegcc*)
+  # two different shell functions defined in ltmain.sh;
+  # decide which one to use based on capabilities of $DLLTOOL
+  case `$DLLTOOL --help 2>&1` in
+  *--identify-strict*)
+    lt_cv_sharedlib_from_linklib_cmd=func_cygming_dll_for_implib
+    ;;
+  *)
+    lt_cv_sharedlib_from_linklib_cmd=func_cygming_dll_for_implib_fallback
+    ;;
+  esac
+  ;;
+*)
+  # fallback: assume linklib IS sharedlib
+  lt_cv_sharedlib_from_linklib_cmd=$ECHO
+  ;;
+esac
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_sharedlib_from_linklib_cmd" >&5
+printf "%s\n" "$lt_cv_sharedlib_from_linklib_cmd" >&6; }
+sharedlib_from_linklib_cmd=$lt_cv_sharedlib_from_linklib_cmd
+test -z "$sharedlib_from_linklib_cmd" && sharedlib_from_linklib_cmd=$ECHO
+
+
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  for ac_prog in ar
+  do
+    # Extract the first word of "$ac_tool_prefix$ac_prog", so it can be a program name with args.
+set dummy $ac_tool_prefix$ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_AR+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$AR"; then
+  ac_cv_prog_AR="$AR" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AR="$ac_tool_prefix$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+AR=$ac_cv_prog_AR
+if test -n "$AR"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $AR" >&5
+printf "%s\n" "$AR" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+    test -n "$AR" && break
+  done
+fi
+if test -z "$AR"; then
+  ac_ct_AR=$AR
+  for ac_prog in ar
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_AR+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_AR"; then
+  ac_cv_prog_ac_ct_AR="$ac_ct_AR" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_AR="$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_AR=$ac_cv_prog_ac_ct_AR
+if test -n "$ac_ct_AR"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_AR" >&5
+printf "%s\n" "$ac_ct_AR" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  test -n "$ac_ct_AR" && break
+done
+
+  if test "x$ac_ct_AR" = x; then
+    AR="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    AR=$ac_ct_AR
+  fi
+fi
+
+: ${AR=ar}
+
+
+
+
+
+
+# Use ARFLAGS variable as AR's operation code to sync the variable naming with
+# Automake.  If both AR_FLAGS and ARFLAGS are specified, AR_FLAGS should have
+# higher priority because thats what people were doing historically (setting
+# ARFLAGS for automake and AR_FLAGS for libtool).  FIXME: Make the AR_FLAGS
+# variable obsoleted/removed.
+
+test ${AR_FLAGS+y} || AR_FLAGS=${ARFLAGS-cr}
+lt_ar_flags=$AR_FLAGS
+
+
+
+
+
+
+# Make AR_FLAGS overridable by 'make ARFLAGS='.  Don't try to run-time override
+# by AR_FLAGS because that was never working and AR_FLAGS is about to die.
+
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for archiver @FILE support" >&5
+printf %s "checking for archiver @FILE support... " >&6; }
+if test ${lt_cv_ar_at_file+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_ar_at_file=no
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  echo conftest.$ac_objext > conftest.lst
+      lt_ar_try='$AR $AR_FLAGS libconftest.a @conftest.lst >&5'
+      { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$lt_ar_try\""; } >&5
+  (eval $lt_ar_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+      if test 0 -eq "$ac_status"; then
+	# Ensure the archiver fails upon bogus file names.
+	rm -f conftest.$ac_objext libconftest.a
+	{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$lt_ar_try\""; } >&5
+  (eval $lt_ar_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+	if test 0 -ne "$ac_status"; then
+          lt_cv_ar_at_file=@
+        fi
+      fi
+      rm -f conftest.* libconftest.a
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+   ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_ar_at_file" >&5
+printf "%s\n" "$lt_cv_ar_at_file" >&6; }
+
+if test no = "$lt_cv_ar_at_file"; then
+  archiver_list_spec=
+else
+  archiver_list_spec=$lt_cv_ar_at_file
+fi
+
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}strip", so it can be a program name with args.
+set dummy ${ac_tool_prefix}strip; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_STRIP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$STRIP"; then
+  ac_cv_prog_STRIP="$STRIP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_STRIP="${ac_tool_prefix}strip"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+STRIP=$ac_cv_prog_STRIP
+if test -n "$STRIP"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $STRIP" >&5
+printf "%s\n" "$STRIP" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_STRIP"; then
+  ac_ct_STRIP=$STRIP
+  # Extract the first word of "strip", so it can be a program name with args.
+set dummy strip; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_STRIP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_STRIP"; then
+  ac_cv_prog_ac_ct_STRIP="$ac_ct_STRIP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_STRIP="strip"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_STRIP=$ac_cv_prog_ac_ct_STRIP
+if test -n "$ac_ct_STRIP"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_STRIP" >&5
+printf "%s\n" "$ac_ct_STRIP" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_STRIP" = x; then
+    STRIP=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    STRIP=$ac_ct_STRIP
+  fi
+else
+  STRIP="$ac_cv_prog_STRIP"
+fi
+
+test -z "$STRIP" && STRIP=:
+
+
+
+
+
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}ranlib", so it can be a program name with args.
+set dummy ${ac_tool_prefix}ranlib; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_RANLIB+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$RANLIB"; then
+  ac_cv_prog_RANLIB="$RANLIB" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_RANLIB="${ac_tool_prefix}ranlib"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+RANLIB=$ac_cv_prog_RANLIB
+if test -n "$RANLIB"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $RANLIB" >&5
+printf "%s\n" "$RANLIB" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_RANLIB"; then
+  ac_ct_RANLIB=$RANLIB
+  # Extract the first word of "ranlib", so it can be a program name with args.
+set dummy ranlib; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_RANLIB+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_RANLIB"; then
+  ac_cv_prog_ac_ct_RANLIB="$ac_ct_RANLIB" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_RANLIB="ranlib"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_RANLIB=$ac_cv_prog_ac_ct_RANLIB
+if test -n "$ac_ct_RANLIB"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_RANLIB" >&5
+printf "%s\n" "$ac_ct_RANLIB" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_RANLIB" = x; then
+    RANLIB=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    RANLIB=$ac_ct_RANLIB
+  fi
+else
+  RANLIB="$ac_cv_prog_RANLIB"
+fi
+
+test -z "$RANLIB" && RANLIB=:
+
+
+
+
+
+
+# Determine commands to create old-style static archives.
+old_archive_cmds='$AR $AR_FLAGS $oldlib$oldobjs'
+old_postinstall_cmds='chmod 644 $oldlib'
+old_postuninstall_cmds=
+
+if test -n "$RANLIB"; then
+  case $host_os in
+  bitrig* | openbsd*)
+    old_postinstall_cmds="$old_postinstall_cmds~\$RANLIB -t \$tool_oldlib"
+    ;;
+  *)
+    old_postinstall_cmds="$old_postinstall_cmds~\$RANLIB \$tool_oldlib"
+    ;;
+  esac
+  old_archive_cmds="$old_archive_cmds~\$RANLIB \$tool_oldlib"
+fi
+
+case $host_os in
+  darwin*)
+    lock_old_archive_extraction=yes ;;
+  *)
+    lock_old_archive_extraction=no ;;
+esac
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+# If no C compiler was specified, use CC.
+LTCC=${LTCC-"$CC"}
+
+# If no C compiler flags were specified, use CFLAGS.
+LTCFLAGS=${LTCFLAGS-"$CFLAGS"}
+
+# Allow CC to be a program name with arguments.
+compiler=$CC
+
+
+# Check for command to grab the raw symbol name followed by C symbol from nm.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking command to parse $NM output from $compiler object" >&5
+printf %s "checking command to parse $NM output from $compiler object... " >&6; }
+if test ${lt_cv_sys_global_symbol_pipe+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e)
+# These are sane defaults that work on at least a few old systems.
+# [They come from Ultrix.  What could be older than Ultrix?!! ;)]
+
+# Character class describing NM global symbol codes.
+symcode='[BCDEGRST]'
+
+# Regexp to match symbols that can be accessed directly from C.
+sympat='\([_A-Za-z][_A-Za-z0-9]*\)'
+
+# Define system-specific variables.
+case $host_os in
+aix*)
+  symcode='[BCDT]'
+  ;;
+cygwin* | mingw* | pw32* | cegcc*)
+  symcode='[ABCDGISTW]'
+  ;;
+hpux*)
+  if test ia64 = "$host_cpu"; then
+    symcode='[ABCDEGRST]'
+  fi
+  ;;
+irix* | nonstopux*)
+  symcode='[BCDEGRST]'
+  ;;
+osf*)
+  symcode='[BCDEGQRST]'
+  ;;
+solaris*)
+  symcode='[BDRT]'
+  ;;
+sco3.2v5*)
+  symcode='[DT]'
+  ;;
+sysv4.2uw2*)
+  symcode='[DT]'
+  ;;
+sysv5* | sco5v6* | unixware* | OpenUNIX*)
+  symcode='[ABDT]'
+  ;;
+sysv4)
+  symcode='[DFNSTU]'
+  ;;
+esac
+
+# If we're using GNU nm, then use its standard symbol codes.
+case `$NM -V 2>&1` in
+*GNU* | *'with BFD'*)
+  symcode='[ABCDGIRSTW]' ;;
+esac
+
+if test "$lt_cv_nm_interface" = "MS dumpbin"; then
+  # Gets list of data symbols to import.
+  lt_cv_sys_global_symbol_to_import="$SED -n -e 's/^I .* \(.*\)$/\1/p'"
+  # Adjust the below global symbol transforms to fixup imported variables.
+  lt_cdecl_hook=" -e 's/^I .* \(.*\)$/extern __declspec(dllimport) char \1;/p'"
+  lt_c_name_hook=" -e 's/^I .* \(.*\)$/  {\"\1\", (void *) 0},/p'"
+  lt_c_name_lib_hook="\
+  -e 's/^I .* \(lib.*\)$/  {\"\1\", (void *) 0},/p'\
+  -e 's/^I .* \(.*\)$/  {\"lib\1\", (void *) 0},/p'"
+else
+  # Disable hooks by default.
+  lt_cv_sys_global_symbol_to_import=
+  lt_cdecl_hook=
+  lt_c_name_hook=
+  lt_c_name_lib_hook=
+fi
+
+# Transform an extracted symbol line into a proper C declaration.
+# Some systems (esp. on ia64) link data and code symbols differently,
+# so use this general approach.
+lt_cv_sys_global_symbol_to_cdecl="$SED -n"\
+$lt_cdecl_hook\
+" -e 's/^T .* \(.*\)$/extern int \1();/p'"\
+" -e 's/^$symcode$symcode* .* \(.*\)$/extern char \1;/p'"
+
+# Transform an extracted symbol line into symbol name and symbol address
+lt_cv_sys_global_symbol_to_c_name_address="$SED -n"\
+$lt_c_name_hook\
+" -e 's/^: \(.*\) .*$/  {\"\1\", (void *) 0},/p'"\
+" -e 's/^$symcode$symcode* .* \(.*\)$/  {\"\1\", (void *) \&\1},/p'"
+
+# Transform an extracted symbol line into symbol name with lib prefix and
+# symbol address.
+lt_cv_sys_global_symbol_to_c_name_address_lib_prefix="$SED -n"\
+$lt_c_name_lib_hook\
+" -e 's/^: \(.*\) .*$/  {\"\1\", (void *) 0},/p'"\
+" -e 's/^$symcode$symcode* .* \(lib.*\)$/  {\"\1\", (void *) \&\1},/p'"\
+" -e 's/^$symcode$symcode* .* \(.*\)$/  {\"lib\1\", (void *) \&\1},/p'"
+
+# Handle CRLF in mingw tool chain
+opt_cr=
+case $build_os in
+mingw*)
+  opt_cr=`$ECHO 'x\{0,1\}' | tr x '\015'` # option cr in regexp
+  ;;
+esac
+
+# Try without a prefix underscore, then with it.
+for ac_symprfx in "" "_"; do
+
+  # Transform symcode, sympat, and symprfx into a raw symbol and a C symbol.
+  symxfrm="\\1 $ac_symprfx\\2 \\2"
+
+  # Write the raw and C identifiers.
+  if test "$lt_cv_nm_interface" = "MS dumpbin"; then
+    # Fake it for dumpbin and say T for any non-static function,
+    # D for any global variable and I for any imported variable.
+    # Also find C++ and __fastcall symbols from MSVC++ or ICC,
+    # which start with @ or ?.
+    lt_cv_sys_global_symbol_pipe="$AWK '"\
+"     {last_section=section; section=\$ 3};"\
+"     /^COFF SYMBOL TABLE/{for(i in hide) delete hide[i]};"\
+"     /Section length .*#relocs.*(pick any)/{hide[last_section]=1};"\
+"     /^ *Symbol name *: /{split(\$ 0,sn,\":\"); si=substr(sn[2],2)};"\
+"     /^ *Type *: code/{print \"T\",si,substr(si,length(prfx))};"\
+"     /^ *Type *: data/{print \"I\",si,substr(si,length(prfx))};"\
+"     \$ 0!~/External *\|/{next};"\
+"     / 0+ UNDEF /{next}; / UNDEF \([^|]\)*()/{next};"\
+"     {if(hide[section]) next};"\
+"     {f=\"D\"}; \$ 0~/\(\).*\|/{f=\"T\"};"\
+"     {split(\$ 0,a,/\||\r/); split(a[2],s)};"\
+"     s[1]~/^[@?]/{print f,s[1],s[1]; next};"\
+"     s[1]~prfx {split(s[1],t,\"@\"); print f,t[1],substr(t[1],length(prfx))}"\
+"     ' prfx=^$ac_symprfx"
+  else
+    lt_cv_sys_global_symbol_pipe="$SED -n -e 's/^.*[	 ]\($symcode$symcode*\)[	 ][	 ]*$ac_symprfx$sympat$opt_cr$/$symxfrm/p'"
+  fi
+  lt_cv_sys_global_symbol_pipe="$lt_cv_sys_global_symbol_pipe | $SED '/ __gnu_lto/d'"
+
+  # Check to see that the pipe works correctly.
+  pipe_works=no
+
+  rm -f conftest*
+  cat > conftest.$ac_ext <<_LT_EOF
+#ifdef __cplusplus
+extern "C" {
+#endif
+char nm_test_var;
+void nm_test_func(void);
+void nm_test_func(void){}
+#ifdef __cplusplus
+}
+#endif
+int main(){nm_test_var='a';nm_test_func();return(0);}
+_LT_EOF
+
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    # Now try to grab the symbols.
+    nlist=conftest.nm
+    if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$NM conftest.$ac_objext \| "$lt_cv_sys_global_symbol_pipe" \> $nlist\""; } >&5
+  (eval $NM conftest.$ac_objext \| "$lt_cv_sys_global_symbol_pipe" \> $nlist) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && test -s "$nlist"; then
+      # Try sorting and uniquifying the output.
+      if sort "$nlist" | uniq > "$nlist"T; then
+	mv -f "$nlist"T "$nlist"
+      else
+	rm -f "$nlist"T
+      fi
+
+      # Make sure that we snagged all the symbols we need.
+      if $GREP ' nm_test_var$' "$nlist" >/dev/null; then
+	if $GREP ' nm_test_func$' "$nlist" >/dev/null; then
+	  cat <<_LT_EOF > conftest.$ac_ext
+/* Keep this code in sync between libtool.m4, ltmain, lt_system.h, and tests.  */
+#if defined _WIN32 || defined __CYGWIN__ || defined _WIN32_WCE
+/* DATA imports from DLLs on WIN32 can't be const, because runtime
+   relocations are performed -- see ld's documentation on pseudo-relocs.  */
+# define LT_DLSYM_CONST
+#elif defined __osf__
+/* This system does not cope well with relocations in const data.  */
+# define LT_DLSYM_CONST
+#else
+# define LT_DLSYM_CONST const
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+_LT_EOF
+	  # Now generate the symbol file.
+	  eval "$lt_cv_sys_global_symbol_to_cdecl"' < "$nlist" | $GREP -v main >> conftest.$ac_ext'
+
+	  cat <<_LT_EOF >> conftest.$ac_ext
+
+/* The mapping between symbol names and symbols.  */
+LT_DLSYM_CONST struct {
+  const char *name;
+  void       *address;
+}
+lt__PROGRAM__LTX_preloaded_symbols[] =
+{
+  { "@PROGRAM@", (void *) 0 },
+_LT_EOF
+	  $SED "s/^$symcode$symcode* .* \(.*\)$/  {\"\1\", (void *) \&\1},/" < "$nlist" | $GREP -v main >> conftest.$ac_ext
+	  cat <<\_LT_EOF >> conftest.$ac_ext
+  {0, (void *) 0}
+};
+
+/* This works around a problem in FreeBSD linker */
+#ifdef FREEBSD_WORKAROUND
+static const void *lt_preloaded_setup() {
+  return lt__PROGRAM__LTX_preloaded_symbols;
+}
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+_LT_EOF
+	  # Now try linking the two files.
+	  mv conftest.$ac_objext conftstm.$ac_objext
+	  lt_globsym_save_LIBS=$LIBS
+	  lt_globsym_save_CFLAGS=$CFLAGS
+	  LIBS=conftstm.$ac_objext
+	  CFLAGS="$CFLAGS$lt_prog_compiler_no_builtin_flag"
+	  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_link\""; } >&5
+  (eval $ac_link) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && test -s conftest$ac_exeext; then
+	    pipe_works=yes
+	  fi
+	  LIBS=$lt_globsym_save_LIBS
+	  CFLAGS=$lt_globsym_save_CFLAGS
+	else
+	  echo "cannot find nm_test_func in $nlist" >&5
+	fi
+      else
+	echo "cannot find nm_test_var in $nlist" >&5
+      fi
+    else
+      echo "cannot run $lt_cv_sys_global_symbol_pipe" >&5
+    fi
+  else
+    echo "$progname: failed program was:" >&5
+    cat conftest.$ac_ext >&5
+  fi
+  rm -rf conftest* conftst*
+
+  # Do not use the global_symbol_pipe unless it works.
+  if test yes = "$pipe_works"; then
+    break
+  else
+    lt_cv_sys_global_symbol_pipe=
+  fi
+done
+ ;;
+esac
+fi
+
+if test -z "$lt_cv_sys_global_symbol_pipe"; then
+  lt_cv_sys_global_symbol_to_cdecl=
+fi
+if test -z "$lt_cv_sys_global_symbol_pipe$lt_cv_sys_global_symbol_to_cdecl"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: failed" >&5
+printf "%s\n" "failed" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: ok" >&5
+printf "%s\n" "ok" >&6; }
+fi
+
+# Response file support.
+if test "$lt_cv_nm_interface" = "MS dumpbin"; then
+  nm_file_list_spec='@'
+elif $NM --help 2>/dev/null | grep '[@]FILE' >/dev/null; then
+  nm_file_list_spec='@'
+fi
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for sysroot" >&5
+printf %s "checking for sysroot... " >&6; }
+
+# Check whether --with-sysroot was given.
+if test ${with_sysroot+y}
+then :
+  withval=$with_sysroot;
+else case e in #(
+  e) with_sysroot=no ;;
+esac
+fi
+
+
+lt_sysroot=
+case $with_sysroot in #(
+ yes)
+   if test yes = "$GCC"; then
+     lt_sysroot=`$CC --print-sysroot 2>/dev/null`
+   fi
+   ;; #(
+ /*)
+   lt_sysroot=`echo "$with_sysroot" | $SED -e "$sed_quote_subst"`
+   ;; #(
+ no|'')
+   ;; #(
+ *)
+   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $with_sysroot" >&5
+printf "%s\n" "$with_sysroot" >&6; }
+   as_fn_error $? "The sysroot must be an absolute path." "$LINENO" 5
+   ;;
+esac
+
+ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: ${lt_sysroot:-no}" >&5
+printf "%s\n" "${lt_sysroot:-no}" >&6; }
+
+
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for a working dd" >&5
+printf %s "checking for a working dd... " >&6; }
+if test ${ac_cv_path_lt_DD+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) printf 0123456789abcdef0123456789abcdef >conftest.i
+cat conftest.i conftest.i >conftest2.i
+: ${lt_DD:=$DD}
+if test -z "$lt_DD"; then
+  ac_path_lt_DD_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_prog in dd
+   do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_lt_DD="$as_dir$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_lt_DD" || continue
+if "$ac_path_lt_DD" bs=32 count=1 <conftest2.i >conftest.out 2>/dev/null; then
+  cmp -s conftest.i conftest.out \
+  && ac_cv_path_lt_DD="$ac_path_lt_DD" ac_path_lt_DD_found=:
+fi
+      $ac_path_lt_DD_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_lt_DD"; then
+    :
+  fi
+else
+  ac_cv_path_lt_DD=$lt_DD
+fi
+
+rm -f conftest.i conftest2.i conftest.out ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_lt_DD" >&5
+printf "%s\n" "$ac_cv_path_lt_DD" >&6; }
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking how to truncate binary pipes" >&5
+printf %s "checking how to truncate binary pipes... " >&6; }
+if test ${lt_cv_truncate_bin+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) printf 0123456789abcdef0123456789abcdef >conftest.i
+cat conftest.i conftest.i >conftest2.i
+lt_cv_truncate_bin=
+if "$ac_cv_path_lt_DD" bs=32 count=1 <conftest2.i >conftest.out 2>/dev/null; then
+  cmp -s conftest.i conftest.out \
+  && lt_cv_truncate_bin="$ac_cv_path_lt_DD bs=4096 count=1"
+fi
+rm -f conftest.i conftest2.i conftest.out
+test -z "$lt_cv_truncate_bin" && lt_cv_truncate_bin="$SED -e 4q" ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_truncate_bin" >&5
+printf "%s\n" "$lt_cv_truncate_bin" >&6; }
+
+
+
+
+
+
+
+# Calculate cc_basename.  Skip known compiler wrappers and cross-prefix.
+func_cc_basename ()
+{
+    for cc_temp in $*""; do
+      case $cc_temp in
+        compile | *[\\/]compile | ccache | *[\\/]ccache ) ;;
+        distcc | *[\\/]distcc | purify | *[\\/]purify ) ;;
+        \-*) ;;
+        *) break;;
+      esac
+    done
+    func_cc_basename_result=`$ECHO "$cc_temp" | $SED "s%.*/%%; s%^$host_alias-%%"`
+}
+
+# Check whether --enable-libtool-lock was given.
+if test ${enable_libtool_lock+y}
+then :
+  enableval=$enable_libtool_lock;
+fi
+
+test no = "$enable_libtool_lock" || enable_libtool_lock=yes
+
+# Some flags need to be propagated to the compiler or linker for good
+# libtool support.
+case $host in
+ia64-*-hpux*)
+  # Find out what ABI is being produced by ac_compile, and set mode
+  # options accordingly.
+  echo 'int i;' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    case `$FILECMD conftest.$ac_objext` in
+      *ELF-32*)
+	HPUX_IA64_MODE=32
+	;;
+      *ELF-64*)
+	HPUX_IA64_MODE=64
+	;;
+    esac
+  fi
+  rm -rf conftest*
+  ;;
+*-*-irix6*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.
+  echo '#line '$LINENO' "configure"' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    if test yes = "$lt_cv_prog_gnu_ld"; then
+      case `$FILECMD conftest.$ac_objext` in
+	*32-bit*)
+	  LD="${LD-ld} -melf32bsmip"
+	  ;;
+	*N32*)
+	  LD="${LD-ld} -melf32bmipn32"
+	  ;;
+	*64-bit*)
+	  LD="${LD-ld} -melf64bmip"
+	;;
+      esac
+    else
+      case `$FILECMD conftest.$ac_objext` in
+	*32-bit*)
+	  LD="${LD-ld} -32"
+	  ;;
+	*N32*)
+	  LD="${LD-ld} -n32"
+	  ;;
+	*64-bit*)
+	  LD="${LD-ld} -64"
+	  ;;
+      esac
+    fi
+  fi
+  rm -rf conftest*
+  ;;
+
+mips64*-*linux*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.
+  echo '#line '$LINENO' "configure"' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    emul=elf
+    case `$FILECMD conftest.$ac_objext` in
+      *32-bit*)
+	emul="${emul}32"
+	;;
+      *64-bit*)
+	emul="${emul}64"
+	;;
+    esac
+    case `$FILECMD conftest.$ac_objext` in
+      *MSB*)
+	emul="${emul}btsmip"
+	;;
+      *LSB*)
+	emul="${emul}ltsmip"
+	;;
+    esac
+    case `$FILECMD conftest.$ac_objext` in
+      *N32*)
+	emul="${emul}n32"
+	;;
+    esac
+    LD="${LD-ld} -m $emul"
+  fi
+  rm -rf conftest*
+  ;;
+
+x86_64-*kfreebsd*-gnu|x86_64-*linux*|powerpc*-*linux*| \
+s390*-*linux*|s390*-*tpf*|sparc*-*linux*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.  Note that the listed cases only cover the
+  # situations where additional linker options are needed (such as when
+  # doing 32-bit compilation for a host where ld defaults to 64-bit, or
+  # vice versa); the common cases where no linker options are needed do
+  # not appear in the list.
+  echo 'int i;' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    case `$FILECMD conftest.o` in
+      *32-bit*)
+	case $host in
+	  x86_64-*kfreebsd*-gnu)
+	    LD="${LD-ld} -m elf_i386_fbsd"
+	    ;;
+	  x86_64-*linux*)
+	    case `$FILECMD conftest.o` in
+	      *x86-64*)
+		LD="${LD-ld} -m elf32_x86_64"
+		;;
+	      *)
+		LD="${LD-ld} -m elf_i386"
+		;;
+	    esac
+	    ;;
+	  powerpc64le-*linux*)
+	    LD="${LD-ld} -m elf32lppclinux"
+	    ;;
+	  powerpc64-*linux*)
+	    LD="${LD-ld} -m elf32ppclinux"
+	    ;;
+	  s390x-*linux*)
+	    LD="${LD-ld} -m elf_s390"
+	    ;;
+	  sparc64-*linux*)
+	    LD="${LD-ld} -m elf32_sparc"
+	    ;;
+	esac
+	;;
+      *64-bit*)
+	case $host in
+	  x86_64-*kfreebsd*-gnu)
+	    LD="${LD-ld} -m elf_x86_64_fbsd"
+	    ;;
+	  x86_64-*linux*)
+	    LD="${LD-ld} -m elf_x86_64"
+	    ;;
+	  powerpcle-*linux*)
+	    LD="${LD-ld} -m elf64lppc"
+	    ;;
+	  powerpc-*linux*)
+	    LD="${LD-ld} -m elf64ppc"
+	    ;;
+	  s390*-*linux*|s390*-*tpf*)
+	    LD="${LD-ld} -m elf64_s390"
+	    ;;
+	  sparc*-*linux*)
+	    LD="${LD-ld} -m elf64_sparc"
+	    ;;
+	esac
+	;;
+    esac
+  fi
+  rm -rf conftest*
+  ;;
+
+*-*-sco3.2v5*)
+  # On SCO OpenServer 5, we need -belf to get full-featured binaries.
+  SAVE_CFLAGS=$CFLAGS
+  CFLAGS="$CFLAGS -belf"
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the C compiler needs -belf" >&5
+printf %s "checking whether the C compiler needs -belf... " >&6; }
+if test ${lt_cv_cc_needs_belf+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  lt_cv_cc_needs_belf=yes
+else case e in #(
+  e) lt_cv_cc_needs_belf=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+     ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_cc_needs_belf" >&5
+printf "%s\n" "$lt_cv_cc_needs_belf" >&6; }
+  if test yes != "$lt_cv_cc_needs_belf"; then
+    # this is probably gcc 2.8.0, egcs 1.0 or newer; no need for -belf
+    CFLAGS=$SAVE_CFLAGS
+  fi
+  ;;
+*-*solaris*)
+  # Find out what ABI is being produced by ac_compile, and set linker
+  # options accordingly.
+  echo 'int i;' > conftest.$ac_ext
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; then
+    case `$FILECMD conftest.o` in
+    *64-bit*)
+      case $lt_cv_prog_gnu_ld in
+      yes*)
+        case $host in
+        i?86-*-solaris*|x86_64-*-solaris*)
+          LD="${LD-ld} -m elf_x86_64"
+          ;;
+        sparc*-*-solaris*)
+          LD="${LD-ld} -m elf64_sparc"
+          ;;
+        esac
+        # GNU ld 2.21 introduced _sol2 emulations.  Use them if available.
+        if ${LD-ld} -V | grep _sol2 >/dev/null 2>&1; then
+          LD=${LD-ld}_sol2
+        fi
+        ;;
+      *)
+	if ${LD-ld} -64 -r -o conftest2.o conftest.o >/dev/null 2>&1; then
+	  LD="${LD-ld} -64"
+	fi
+	;;
+      esac
+      ;;
+    esac
+  fi
+  rm -rf conftest*
+  ;;
+esac
+
+need_locks=$enable_libtool_lock
+
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}mt", so it can be a program name with args.
+set dummy ${ac_tool_prefix}mt; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_MANIFEST_TOOL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$MANIFEST_TOOL"; then
+  ac_cv_prog_MANIFEST_TOOL="$MANIFEST_TOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_MANIFEST_TOOL="${ac_tool_prefix}mt"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+MANIFEST_TOOL=$ac_cv_prog_MANIFEST_TOOL
+if test -n "$MANIFEST_TOOL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $MANIFEST_TOOL" >&5
+printf "%s\n" "$MANIFEST_TOOL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_MANIFEST_TOOL"; then
+  ac_ct_MANIFEST_TOOL=$MANIFEST_TOOL
+  # Extract the first word of "mt", so it can be a program name with args.
+set dummy mt; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_MANIFEST_TOOL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_MANIFEST_TOOL"; then
+  ac_cv_prog_ac_ct_MANIFEST_TOOL="$ac_ct_MANIFEST_TOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_MANIFEST_TOOL="mt"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_MANIFEST_TOOL=$ac_cv_prog_ac_ct_MANIFEST_TOOL
+if test -n "$ac_ct_MANIFEST_TOOL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_MANIFEST_TOOL" >&5
+printf "%s\n" "$ac_ct_MANIFEST_TOOL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_MANIFEST_TOOL" = x; then
+    MANIFEST_TOOL=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    MANIFEST_TOOL=$ac_ct_MANIFEST_TOOL
+  fi
+else
+  MANIFEST_TOOL="$ac_cv_prog_MANIFEST_TOOL"
+fi
+
+test -z "$MANIFEST_TOOL" && MANIFEST_TOOL=mt
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if $MANIFEST_TOOL is a manifest tool" >&5
+printf %s "checking if $MANIFEST_TOOL is a manifest tool... " >&6; }
+if test ${lt_cv_path_mainfest_tool+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_path_mainfest_tool=no
+  echo "$as_me:$LINENO: $MANIFEST_TOOL '-?'" >&5
+  $MANIFEST_TOOL '-?' 2>conftest.err > conftest.out
+  cat conftest.err >&5
+  if $GREP 'Manifest Tool' conftest.out > /dev/null; then
+    lt_cv_path_mainfest_tool=yes
+  fi
+  rm -f conftest* ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_path_mainfest_tool" >&5
+printf "%s\n" "$lt_cv_path_mainfest_tool" >&6; }
+if test yes != "$lt_cv_path_mainfest_tool"; then
+  MANIFEST_TOOL=:
+fi
+
+
+
+
+
+
+  case $host_os in
+    rhapsody* | darwin*)
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}dsymutil", so it can be a program name with args.
+set dummy ${ac_tool_prefix}dsymutil; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_DSYMUTIL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$DSYMUTIL"; then
+  ac_cv_prog_DSYMUTIL="$DSYMUTIL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_DSYMUTIL="${ac_tool_prefix}dsymutil"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+DSYMUTIL=$ac_cv_prog_DSYMUTIL
+if test -n "$DSYMUTIL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $DSYMUTIL" >&5
+printf "%s\n" "$DSYMUTIL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_DSYMUTIL"; then
+  ac_ct_DSYMUTIL=$DSYMUTIL
+  # Extract the first word of "dsymutil", so it can be a program name with args.
+set dummy dsymutil; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_DSYMUTIL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_DSYMUTIL"; then
+  ac_cv_prog_ac_ct_DSYMUTIL="$ac_ct_DSYMUTIL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_DSYMUTIL="dsymutil"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_DSYMUTIL=$ac_cv_prog_ac_ct_DSYMUTIL
+if test -n "$ac_ct_DSYMUTIL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_DSYMUTIL" >&5
+printf "%s\n" "$ac_ct_DSYMUTIL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_DSYMUTIL" = x; then
+    DSYMUTIL=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    DSYMUTIL=$ac_ct_DSYMUTIL
+  fi
+else
+  DSYMUTIL="$ac_cv_prog_DSYMUTIL"
+fi
+
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}nmedit", so it can be a program name with args.
+set dummy ${ac_tool_prefix}nmedit; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_NMEDIT+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$NMEDIT"; then
+  ac_cv_prog_NMEDIT="$NMEDIT" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_NMEDIT="${ac_tool_prefix}nmedit"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+NMEDIT=$ac_cv_prog_NMEDIT
+if test -n "$NMEDIT"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $NMEDIT" >&5
+printf "%s\n" "$NMEDIT" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_NMEDIT"; then
+  ac_ct_NMEDIT=$NMEDIT
+  # Extract the first word of "nmedit", so it can be a program name with args.
+set dummy nmedit; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_NMEDIT+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_NMEDIT"; then
+  ac_cv_prog_ac_ct_NMEDIT="$ac_ct_NMEDIT" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_NMEDIT="nmedit"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_NMEDIT=$ac_cv_prog_ac_ct_NMEDIT
+if test -n "$ac_ct_NMEDIT"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_NMEDIT" >&5
+printf "%s\n" "$ac_ct_NMEDIT" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_NMEDIT" = x; then
+    NMEDIT=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    NMEDIT=$ac_ct_NMEDIT
+  fi
+else
+  NMEDIT="$ac_cv_prog_NMEDIT"
+fi
+
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}lipo", so it can be a program name with args.
+set dummy ${ac_tool_prefix}lipo; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_LIPO+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$LIPO"; then
+  ac_cv_prog_LIPO="$LIPO" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_LIPO="${ac_tool_prefix}lipo"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+LIPO=$ac_cv_prog_LIPO
+if test -n "$LIPO"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $LIPO" >&5
+printf "%s\n" "$LIPO" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_LIPO"; then
+  ac_ct_LIPO=$LIPO
+  # Extract the first word of "lipo", so it can be a program name with args.
+set dummy lipo; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_LIPO+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_LIPO"; then
+  ac_cv_prog_ac_ct_LIPO="$ac_ct_LIPO" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_LIPO="lipo"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_LIPO=$ac_cv_prog_ac_ct_LIPO
+if test -n "$ac_ct_LIPO"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_LIPO" >&5
+printf "%s\n" "$ac_ct_LIPO" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_LIPO" = x; then
+    LIPO=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    LIPO=$ac_ct_LIPO
+  fi
+else
+  LIPO="$ac_cv_prog_LIPO"
+fi
+
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}otool", so it can be a program name with args.
+set dummy ${ac_tool_prefix}otool; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_OTOOL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$OTOOL"; then
+  ac_cv_prog_OTOOL="$OTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_OTOOL="${ac_tool_prefix}otool"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+OTOOL=$ac_cv_prog_OTOOL
+if test -n "$OTOOL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $OTOOL" >&5
+printf "%s\n" "$OTOOL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_OTOOL"; then
+  ac_ct_OTOOL=$OTOOL
+  # Extract the first word of "otool", so it can be a program name with args.
+set dummy otool; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_OTOOL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_OTOOL"; then
+  ac_cv_prog_ac_ct_OTOOL="$ac_ct_OTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_OTOOL="otool"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_OTOOL=$ac_cv_prog_ac_ct_OTOOL
+if test -n "$ac_ct_OTOOL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_OTOOL" >&5
+printf "%s\n" "$ac_ct_OTOOL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_OTOOL" = x; then
+    OTOOL=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    OTOOL=$ac_ct_OTOOL
+  fi
+else
+  OTOOL="$ac_cv_prog_OTOOL"
+fi
+
+    if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}otool64", so it can be a program name with args.
+set dummy ${ac_tool_prefix}otool64; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_OTOOL64+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$OTOOL64"; then
+  ac_cv_prog_OTOOL64="$OTOOL64" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_OTOOL64="${ac_tool_prefix}otool64"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+OTOOL64=$ac_cv_prog_OTOOL64
+if test -n "$OTOOL64"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $OTOOL64" >&5
+printf "%s\n" "$OTOOL64" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_OTOOL64"; then
+  ac_ct_OTOOL64=$OTOOL64
+  # Extract the first word of "otool64", so it can be a program name with args.
+set dummy otool64; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_OTOOL64+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_OTOOL64"; then
+  ac_cv_prog_ac_ct_OTOOL64="$ac_ct_OTOOL64" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_OTOOL64="otool64"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_OTOOL64=$ac_cv_prog_ac_ct_OTOOL64
+if test -n "$ac_ct_OTOOL64"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_OTOOL64" >&5
+printf "%s\n" "$ac_ct_OTOOL64" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_OTOOL64" = x; then
+    OTOOL64=":"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    OTOOL64=$ac_ct_OTOOL64
+  fi
+else
+  OTOOL64="$ac_cv_prog_OTOOL64"
+fi
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -single_module linker flag" >&5
+printf %s "checking for -single_module linker flag... " >&6; }
+if test ${lt_cv_apple_cc_single_mod+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_apple_cc_single_mod=no
+      if test -z "$LT_MULTI_MODULE"; then
+	# By default we will add the -single_module flag. You can override
+	# by either setting the environment variable LT_MULTI_MODULE
+	# non-empty at configure time, or by adding -multi_module to the
+	# link flags.
+	rm -rf libconftest.dylib*
+	echo "int foo(void){return 1;}" > conftest.c
+	echo "$LTCC $LTCFLAGS $LDFLAGS -o libconftest.dylib \
+-dynamiclib -Wl,-single_module conftest.c" >&5
+	$LTCC $LTCFLAGS $LDFLAGS -o libconftest.dylib \
+	  -dynamiclib -Wl,-single_module conftest.c 2>conftest.err
+        _lt_result=$?
+	# If there is a non-empty error log, and "single_module"
+	# appears in it, assume the flag caused a linker warning
+        if test -s conftest.err && $GREP single_module conftest.err; then
+	  cat conftest.err >&5
+	# Otherwise, if the output was created with a 0 exit code from
+	# the compiler, it worked.
+	elif test -f libconftest.dylib && test 0 = "$_lt_result"; then
+	  lt_cv_apple_cc_single_mod=yes
+	else
+	  cat conftest.err >&5
+	fi
+	rm -rf libconftest.dylib*
+	rm -f conftest.*
+      fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_apple_cc_single_mod" >&5
+printf "%s\n" "$lt_cv_apple_cc_single_mod" >&6; }
+
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -exported_symbols_list linker flag" >&5
+printf %s "checking for -exported_symbols_list linker flag... " >&6; }
+if test ${lt_cv_ld_exported_symbols_list+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_ld_exported_symbols_list=no
+      save_LDFLAGS=$LDFLAGS
+      echo "_main" > conftest.sym
+      LDFLAGS="$LDFLAGS -Wl,-exported_symbols_list,conftest.sym"
+      cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  lt_cv_ld_exported_symbols_list=yes
+else case e in #(
+  e) lt_cv_ld_exported_symbols_list=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+	LDFLAGS=$save_LDFLAGS
+     ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_ld_exported_symbols_list" >&5
+printf "%s\n" "$lt_cv_ld_exported_symbols_list" >&6; }
+
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -force_load linker flag" >&5
+printf %s "checking for -force_load linker flag... " >&6; }
+if test ${lt_cv_ld_force_load+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_ld_force_load=no
+      cat > conftest.c << _LT_EOF
+int forced_loaded() { return 2;}
+_LT_EOF
+      echo "$LTCC $LTCFLAGS -c -o conftest.o conftest.c" >&5
+      $LTCC $LTCFLAGS -c -o conftest.o conftest.c 2>&5
+      echo "$AR $AR_FLAGS libconftest.a conftest.o" >&5
+      $AR $AR_FLAGS libconftest.a conftest.o 2>&5
+      echo "$RANLIB libconftest.a" >&5
+      $RANLIB libconftest.a 2>&5
+      cat > conftest.c << _LT_EOF
+int main() { return 0;}
+_LT_EOF
+      echo "$LTCC $LTCFLAGS $LDFLAGS -o conftest conftest.c -Wl,-force_load,./libconftest.a" >&5
+      $LTCC $LTCFLAGS $LDFLAGS -o conftest conftest.c -Wl,-force_load,./libconftest.a 2>conftest.err
+      _lt_result=$?
+      if test -s conftest.err && $GREP force_load conftest.err; then
+	cat conftest.err >&5
+      elif test -f conftest && test 0 = "$_lt_result" && $GREP forced_load conftest >/dev/null 2>&1; then
+	lt_cv_ld_force_load=yes
+      else
+	cat conftest.err >&5
+      fi
+        rm -f conftest.err libconftest.a conftest conftest.c
+        rm -rf conftest.dSYM
+     ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_ld_force_load" >&5
+printf "%s\n" "$lt_cv_ld_force_load" >&6; }
+    case $host_os in
+    rhapsody* | darwin1.[012])
+      _lt_dar_allow_undefined='$wl-undefined ${wl}suppress' ;;
+    darwin1.*)
+      _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
+    darwin*)
+      case $MACOSX_DEPLOYMENT_TARGET,$host in
+        10.[012],*|,*powerpc*-darwin[5-8]*)
+          _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
+        *)
+          _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
+      esac
+    ;;
+  esac
+    if test yes = "$lt_cv_apple_cc_single_mod"; then
+      _lt_dar_single_mod='$single_module'
+    fi
+    if test yes = "$lt_cv_ld_exported_symbols_list"; then
+      _lt_dar_export_syms=' $wl-exported_symbols_list,$output_objdir/$libname-symbols.expsym'
+    else
+      _lt_dar_export_syms='~$NMEDIT -s $output_objdir/$libname-symbols.expsym $lib'
+    fi
+    if test : != "$DSYMUTIL" && test no = "$lt_cv_ld_force_load"; then
+      _lt_dsymutil='~$DSYMUTIL $lib || :'
+    else
+      _lt_dsymutil=
+    fi
+    ;;
+  esac
+
+# func_munge_path_list VARIABLE PATH
+# -----------------------------------
+# VARIABLE is name of variable containing _space_ separated list of
+# directories to be munged by the contents of PATH, which is string
+# having a format:
+# "DIR[:DIR]:"
+#       string "DIR[ DIR]" will be prepended to VARIABLE
+# ":DIR[:DIR]"
+#       string "DIR[ DIR]" will be appended to VARIABLE
+# "DIRP[:DIRP]::[DIRA:]DIRA"
+#       string "DIRP[ DIRP]" will be prepended to VARIABLE and string
+#       "DIRA[ DIRA]" will be appended to VARIABLE
+# "DIR[:DIR]"
+#       VARIABLE will be replaced by "DIR[ DIR]"
+func_munge_path_list ()
+{
+    case x$2 in
+    x)
+        ;;
+    *:)
+        eval $1=\"`$ECHO $2 | $SED 's/:/ /g'` \$$1\"
+        ;;
+    x:*)
+        eval $1=\"\$$1 `$ECHO $2 | $SED 's/:/ /g'`\"
+        ;;
+    *::*)
+        eval $1=\"\$$1\ `$ECHO $2 | $SED -e 's/.*:://' -e 's/:/ /g'`\"
+        eval $1=\"`$ECHO $2 | $SED -e 's/::.*//' -e 's/:/ /g'`\ \$$1\"
+        ;;
+    *)
+        eval $1=\"`$ECHO $2 | $SED 's/:/ /g'`\"
+        ;;
+    esac
+}
+
+ac_header= ac_cache=
+for ac_item in $ac_header_c_list
+do
+  if test $ac_cache; then
+    ac_fn_c_check_header_compile "$LINENO" $ac_header ac_cv_header_$ac_cache "$ac_includes_default"
+    if eval test \"x\$ac_cv_header_$ac_cache\" = xyes; then
+      printf "%s\n" "#define $ac_item 1" >> confdefs.h
+    fi
+    ac_header= ac_cache=
+  elif test $ac_header; then
+    ac_cache=$ac_item
+  else
+    ac_header=$ac_item
+  fi
+done
+
+
+
+
+
+
+
+
+if test $ac_cv_header_stdlib_h = yes && test $ac_cv_header_string_h = yes
+then :
+
+printf "%s\n" "#define STDC_HEADERS 1" >>confdefs.h
+
+fi
+ac_fn_c_check_header_compile "$LINENO" "dlfcn.h" "ac_cv_header_dlfcn_h" "$ac_includes_default
+"
+if test "x$ac_cv_header_dlfcn_h" = xyes
+then :
+  printf "%s\n" "#define HAVE_DLFCN_H 1" >>confdefs.h
+
+fi
+
+
+
+
+
+# Set options
+enable_win32_dll=yes
+
+case $host in
+*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-cegcc*)
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}as", so it can be a program name with args.
+set dummy ${ac_tool_prefix}as; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_AS+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$AS"; then
+  ac_cv_prog_AS="$AS" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AS="${ac_tool_prefix}as"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+AS=$ac_cv_prog_AS
+if test -n "$AS"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $AS" >&5
+printf "%s\n" "$AS" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_AS"; then
+  ac_ct_AS=$AS
+  # Extract the first word of "as", so it can be a program name with args.
+set dummy as; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_AS+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_AS"; then
+  ac_cv_prog_ac_ct_AS="$ac_ct_AS" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_AS="as"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_AS=$ac_cv_prog_ac_ct_AS
+if test -n "$ac_ct_AS"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_AS" >&5
+printf "%s\n" "$ac_ct_AS" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_AS" = x; then
+    AS="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    AS=$ac_ct_AS
+  fi
+else
+  AS="$ac_cv_prog_AS"
+fi
+
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}dlltool", so it can be a program name with args.
+set dummy ${ac_tool_prefix}dlltool; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_DLLTOOL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$DLLTOOL"; then
+  ac_cv_prog_DLLTOOL="$DLLTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_DLLTOOL="${ac_tool_prefix}dlltool"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+DLLTOOL=$ac_cv_prog_DLLTOOL
+if test -n "$DLLTOOL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $DLLTOOL" >&5
+printf "%s\n" "$DLLTOOL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_DLLTOOL"; then
+  ac_ct_DLLTOOL=$DLLTOOL
+  # Extract the first word of "dlltool", so it can be a program name with args.
+set dummy dlltool; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_DLLTOOL+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_DLLTOOL"; then
+  ac_cv_prog_ac_ct_DLLTOOL="$ac_ct_DLLTOOL" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_DLLTOOL="dlltool"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_DLLTOOL=$ac_cv_prog_ac_ct_DLLTOOL
+if test -n "$ac_ct_DLLTOOL"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_DLLTOOL" >&5
+printf "%s\n" "$ac_ct_DLLTOOL" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_DLLTOOL" = x; then
+    DLLTOOL="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    DLLTOOL=$ac_ct_DLLTOOL
+  fi
+else
+  DLLTOOL="$ac_cv_prog_DLLTOOL"
+fi
+
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}objdump", so it can be a program name with args.
+set dummy ${ac_tool_prefix}objdump; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_OBJDUMP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$OBJDUMP"; then
+  ac_cv_prog_OBJDUMP="$OBJDUMP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_OBJDUMP="${ac_tool_prefix}objdump"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+OBJDUMP=$ac_cv_prog_OBJDUMP
+if test -n "$OBJDUMP"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $OBJDUMP" >&5
+printf "%s\n" "$OBJDUMP" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_OBJDUMP"; then
+  ac_ct_OBJDUMP=$OBJDUMP
+  # Extract the first word of "objdump", so it can be a program name with args.
+set dummy objdump; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_OBJDUMP+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test -n "$ac_ct_OBJDUMP"; then
+  ac_cv_prog_ac_ct_OBJDUMP="$ac_ct_OBJDUMP" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_OBJDUMP="objdump"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi ;;
+esac
+fi
+ac_ct_OBJDUMP=$ac_cv_prog_ac_ct_OBJDUMP
+if test -n "$ac_ct_OBJDUMP"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_OBJDUMP" >&5
+printf "%s\n" "$ac_ct_OBJDUMP" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_OBJDUMP" = x; then
+    OBJDUMP="false"
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    OBJDUMP=$ac_ct_OBJDUMP
+  fi
+else
+  OBJDUMP="$ac_cv_prog_OBJDUMP"
+fi
+
+  ;;
+esac
+
+test -z "$AS" && AS=as
+
+
+
+
+
+test -z "$DLLTOOL" && DLLTOOL=dlltool
+
+
+
+
+
+test -z "$OBJDUMP" && OBJDUMP=objdump
+
+
+
+
+
+
+
+        enable_dlopen=no
+
+
+
+            # Check whether --enable-shared was given.
+if test ${enable_shared+y}
+then :
+  enableval=$enable_shared; p=${PACKAGE-default}
+    case $enableval in
+    yes) enable_shared=yes ;;
+    no) enable_shared=no ;;
+    *)
+      enable_shared=no
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for pkg in $enableval; do
+	IFS=$lt_save_ifs
+	if test "X$pkg" = "X$p"; then
+	  enable_shared=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac
+else case e in #(
+  e) enable_shared=yes ;;
+esac
+fi
+
+
+
+
+
+
+
+
+
+  # Check whether --enable-static was given.
+if test ${enable_static+y}
+then :
+  enableval=$enable_static; p=${PACKAGE-default}
+    case $enableval in
+    yes) enable_static=yes ;;
+    no) enable_static=no ;;
+    *)
+     enable_static=no
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for pkg in $enableval; do
+	IFS=$lt_save_ifs
+	if test "X$pkg" = "X$p"; then
+	  enable_static=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac
+else case e in #(
+  e) enable_static=yes ;;
+esac
+fi
+
+
+
+
+
+
+
+
+
+
+# Check whether --with-pic was given.
+if test ${with_pic+y}
+then :
+  withval=$with_pic; lt_p=${PACKAGE-default}
+    case $withval in
+    yes|no) pic_mode=$withval ;;
+    *)
+      pic_mode=default
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for lt_pkg in $withval; do
+	IFS=$lt_save_ifs
+	if test "X$lt_pkg" = "X$lt_p"; then
+	  pic_mode=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac
+else case e in #(
+  e) pic_mode=default ;;
+esac
+fi
+
+
+
+
+
+
+
+
+  # Check whether --enable-fast-install was given.
+if test ${enable_fast_install+y}
+then :
+  enableval=$enable_fast_install; p=${PACKAGE-default}
+    case $enableval in
+    yes) enable_fast_install=yes ;;
+    no) enable_fast_install=no ;;
+    *)
+      enable_fast_install=no
+      # Look at the argument we got.  We use all the common list separators.
+      lt_save_ifs=$IFS; IFS=$IFS$PATH_SEPARATOR,
+      for pkg in $enableval; do
+	IFS=$lt_save_ifs
+	if test "X$pkg" = "X$p"; then
+	  enable_fast_install=yes
+	fi
+      done
+      IFS=$lt_save_ifs
+      ;;
+    esac
+else case e in #(
+  e) enable_fast_install=yes ;;
+esac
+fi
+
+
+
+
+
+
+
+
+  shared_archive_member_spec=
+case $host,$enable_shared in
+power*-*-aix[5-9]*,yes)
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking which variant of shared library versioning to provide" >&5
+printf %s "checking which variant of shared library versioning to provide... " >&6; }
+
+# Check whether --with-aix-soname was given.
+if test ${with_aix_soname+y}
+then :
+  withval=$with_aix_soname; case $withval in
+    aix|svr4|both)
+      ;;
+    *)
+      as_fn_error $? "Unknown argument to --with-aix-soname" "$LINENO" 5
+      ;;
+    esac
+    lt_cv_with_aix_soname=$with_aix_soname
+else case e in #(
+  e) if test ${lt_cv_with_aix_soname+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_with_aix_soname=aix ;;
+esac
+fi
+
+    with_aix_soname=$lt_cv_with_aix_soname ;;
+esac
+fi
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $with_aix_soname" >&5
+printf "%s\n" "$with_aix_soname" >&6; }
+  if test aix != "$with_aix_soname"; then
+    # For the AIX way of multilib, we name the shared archive member
+    # based on the bitwidth used, traditionally 'shr.o' or 'shr_64.o',
+    # and 'shr.imp' or 'shr_64.imp', respectively, for the Import File.
+    # Even when GNU compilers ignore OBJECT_MODE but need '-maix64' flag,
+    # the AIX toolchain works better with OBJECT_MODE set (default 32).
+    if test 64 = "${OBJECT_MODE-32}"; then
+      shared_archive_member_spec=shr_64
+    else
+      shared_archive_member_spec=shr
+    fi
+  fi
+  ;;
+*)
+  with_aix_soname=aix
+  ;;
+esac
+
+
+
+
+
+
+
+
+
+
+# This can be used to rebuild libtool when needed
+LIBTOOL_DEPS=$ltmain
+
+# Always use our own libtool.
+LIBTOOL='$(SHELL) $(top_builddir)/libtool'
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+test -z "$LN_S" && LN_S="ln -s"
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+if test -n "${ZSH_VERSION+set}"; then
+   setopt NO_GLOB_SUBST
+fi
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for objdir" >&5
+printf %s "checking for objdir... " >&6; }
+if test ${lt_cv_objdir+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) rm -f .libs 2>/dev/null
+mkdir .libs 2>/dev/null
+if test -d .libs; then
+  lt_cv_objdir=.libs
+else
+  # MS-DOS does not allow filenames that begin with a dot.
+  lt_cv_objdir=_libs
+fi
+rmdir .libs 2>/dev/null ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_objdir" >&5
+printf "%s\n" "$lt_cv_objdir" >&6; }
+objdir=$lt_cv_objdir
+
+
+
+
+
+printf "%s\n" "#define LT_OBJDIR \"$lt_cv_objdir/\"" >>confdefs.h
+
+
+
+
+case $host_os in
+aix3*)
+  # AIX sometimes has problems with the GCC collect2 program.  For some
+  # reason, if we set the COLLECT_NAMES environment variable, the problems
+  # vanish in a puff of smoke.
+  if test set != "${COLLECT_NAMES+set}"; then
+    COLLECT_NAMES=
+    export COLLECT_NAMES
+  fi
+  ;;
+esac
+
+# Global variables:
+ofile=libtool
+can_build_shared=yes
+
+# All known linkers require a '.a' archive for static linking (except MSVC and
+# ICC, which need '.lib').
+libext=a
+
+with_gnu_ld=$lt_cv_prog_gnu_ld
+
+old_CC=$CC
+old_CFLAGS=$CFLAGS
+
+# Set sane defaults for various variables
+test -z "$CC" && CC=cc
+test -z "$LTCC" && LTCC=$CC
+test -z "$LTCFLAGS" && LTCFLAGS=$CFLAGS
+test -z "$LD" && LD=ld
+test -z "$ac_objext" && ac_objext=o
+
+func_cc_basename $compiler
+cc_basename=$func_cc_basename_result
+
+
+# Only perform the check for file, if the check method requires it
+test -z "$MAGIC_CMD" && MAGIC_CMD=file
+case $deplibs_check_method in
+file_magic*)
+  if test "$file_magic_cmd" = '$MAGIC_CMD'; then
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for ${ac_tool_prefix}file" >&5
+printf %s "checking for ${ac_tool_prefix}file... " >&6; }
+if test ${lt_cv_path_MAGIC_CMD+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) case $MAGIC_CMD in
+[\\/*] |  ?:[\\/]*)
+  lt_cv_path_MAGIC_CMD=$MAGIC_CMD # Let the user override the test with a path.
+  ;;
+*)
+  lt_save_MAGIC_CMD=$MAGIC_CMD
+  lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+  ac_dummy="/usr/bin$PATH_SEPARATOR$PATH"
+  for ac_dir in $ac_dummy; do
+    IFS=$lt_save_ifs
+    test -z "$ac_dir" && ac_dir=.
+    if test -f "$ac_dir/${ac_tool_prefix}file"; then
+      lt_cv_path_MAGIC_CMD=$ac_dir/"${ac_tool_prefix}file"
+      if test -n "$file_magic_test_file"; then
+	case $deplibs_check_method in
+	"file_magic "*)
+	  file_magic_regex=`expr "$deplibs_check_method" : "file_magic \(.*\)"`
+	  MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+	  if eval $file_magic_cmd \$file_magic_test_file 2> /dev/null |
+	    $EGREP "$file_magic_regex" > /dev/null; then
+	    :
+	  else
+	    cat <<_LT_EOF 1>&2
+
+*** Warning: the command libtool uses to detect shared libraries,
+*** $file_magic_cmd, produces output that libtool cannot recognize.
+*** The result is that libtool may fail to recognize shared libraries
+*** as such.  This will affect the creation of libtool libraries that
+*** depend on shared libraries, but programs linked with such libtool
+*** libraries will work regardless of this problem.  Nevertheless, you
+*** may want to report the problem to your system manager and/or to
+*** bug-libtool@gnu.org
+
+_LT_EOF
+	  fi ;;
+	esac
+      fi
+      break
+    fi
+  done
+  IFS=$lt_save_ifs
+  MAGIC_CMD=$lt_save_MAGIC_CMD
+  ;;
+esac ;;
+esac
+fi
+
+MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+if test -n "$MAGIC_CMD"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $MAGIC_CMD" >&5
+printf "%s\n" "$MAGIC_CMD" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+
+
+
+if test -z "$lt_cv_path_MAGIC_CMD"; then
+  if test -n "$ac_tool_prefix"; then
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for file" >&5
+printf %s "checking for file... " >&6; }
+if test ${lt_cv_path_MAGIC_CMD+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) case $MAGIC_CMD in
+[\\/*] |  ?:[\\/]*)
+  lt_cv_path_MAGIC_CMD=$MAGIC_CMD # Let the user override the test with a path.
+  ;;
+*)
+  lt_save_MAGIC_CMD=$MAGIC_CMD
+  lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
+  ac_dummy="/usr/bin$PATH_SEPARATOR$PATH"
+  for ac_dir in $ac_dummy; do
+    IFS=$lt_save_ifs
+    test -z "$ac_dir" && ac_dir=.
+    if test -f "$ac_dir/file"; then
+      lt_cv_path_MAGIC_CMD=$ac_dir/"file"
+      if test -n "$file_magic_test_file"; then
+	case $deplibs_check_method in
+	"file_magic "*)
+	  file_magic_regex=`expr "$deplibs_check_method" : "file_magic \(.*\)"`
+	  MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+	  if eval $file_magic_cmd \$file_magic_test_file 2> /dev/null |
+	    $EGREP "$file_magic_regex" > /dev/null; then
+	    :
+	  else
+	    cat <<_LT_EOF 1>&2
+
+*** Warning: the command libtool uses to detect shared libraries,
+*** $file_magic_cmd, produces output that libtool cannot recognize.
+*** The result is that libtool may fail to recognize shared libraries
+*** as such.  This will affect the creation of libtool libraries that
+*** depend on shared libraries, but programs linked with such libtool
+*** libraries will work regardless of this problem.  Nevertheless, you
+*** may want to report the problem to your system manager and/or to
+*** bug-libtool@gnu.org
+
+_LT_EOF
+	  fi ;;
+	esac
+      fi
+      break
+    fi
+  done
+  IFS=$lt_save_ifs
+  MAGIC_CMD=$lt_save_MAGIC_CMD
+  ;;
+esac ;;
+esac
+fi
+
+MAGIC_CMD=$lt_cv_path_MAGIC_CMD
+if test -n "$MAGIC_CMD"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $MAGIC_CMD" >&5
+printf "%s\n" "$MAGIC_CMD" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  else
+    MAGIC_CMD=:
+  fi
+fi
+
+  fi
+  ;;
+esac
+
+# Use C for the default configuration in the libtool script
+
+lt_save_CC=$CC
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+# Source file extension for C test sources.
+ac_ext=c
+
+# Object file extension for compiled C test sources.
+objext=o
+objext=$objext
+
+# Code to be used in simple compile tests
+lt_simple_compile_test_code="int some_variable = 0;"
+
+# Code to be used in simple link tests
+lt_simple_link_test_code='int main(){return(0);}'
+
+
+
+
+
+
+
+# If no C compiler was specified, use CC.
+LTCC=${LTCC-"$CC"}
+
+# If no C compiler flags were specified, use CFLAGS.
+LTCFLAGS=${LTCFLAGS-"$CFLAGS"}
+
+# Allow CC to be a program name with arguments.
+compiler=$CC
+
+# Save the default compiler, since it gets overwritten when the other
+# tags are being tested, and _LT_TAGVAR(compiler, []) is a NOP.
+compiler_DEFAULT=$CC
+
+# save warnings/boilerplate of simple test code
+ac_outfile=conftest.$ac_objext
+echo "$lt_simple_compile_test_code" >conftest.$ac_ext
+eval "$ac_compile" 2>&1 >/dev/null | $SED '/^$/d; /^ *+/d' >conftest.err
+_lt_compiler_boilerplate=`cat conftest.err`
+$RM conftest*
+
+ac_outfile=conftest.$ac_objext
+echo "$lt_simple_link_test_code" >conftest.$ac_ext
+eval "$ac_link" 2>&1 >/dev/null | $SED '/^$/d; /^ *+/d' >conftest.err
+_lt_linker_boilerplate=`cat conftest.err`
+$RM -r conftest*
+
+
+## CAVEAT EMPTOR:
+## There is no encapsulation within the following macros, do not change
+## the running order or otherwise move them around unless you know exactly
+## what you are doing...
+if test -n "$compiler"; then
+
+lt_prog_compiler_no_builtin_flag=
+
+if test yes = "$GCC"; then
+  case $cc_basename in
+  nvcc*)
+    lt_prog_compiler_no_builtin_flag=' -Xcompiler -fno-builtin' ;;
+  *)
+    lt_prog_compiler_no_builtin_flag=' -fno-builtin' ;;
+  esac
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if $compiler supports -fno-rtti -fno-exceptions" >&5
+printf %s "checking if $compiler supports -fno-rtti -fno-exceptions... " >&6; }
+if test ${lt_cv_prog_compiler_rtti_exceptions+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_prog_compiler_rtti_exceptions=no
+   ac_outfile=conftest.$ac_objext
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+   lt_compiler_flag="-fno-rtti -fno-exceptions"  ## exclude from sc_useless_quotes_in_assignment
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   # The option is referenced via a variable to avoid confusing sed.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&5)
+   (eval "$lt_compile" 2>conftest.err)
+   ac_status=$?
+   cat conftest.err >&5
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   if (exit $ac_status) && test -s "$ac_outfile"; then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings other than the usual output.
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' >conftest.exp
+     $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+     if test ! -s conftest.er2 || diff conftest.exp conftest.er2 >/dev/null; then
+       lt_cv_prog_compiler_rtti_exceptions=yes
+     fi
+   fi
+   $RM conftest*
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_rtti_exceptions" >&5
+printf "%s\n" "$lt_cv_prog_compiler_rtti_exceptions" >&6; }
+
+if test yes = "$lt_cv_prog_compiler_rtti_exceptions"; then
+    lt_prog_compiler_no_builtin_flag="$lt_prog_compiler_no_builtin_flag -fno-rtti -fno-exceptions"
+else
+    :
+fi
+
+fi
+
+
+
+
+
+
+  lt_prog_compiler_wl=
+lt_prog_compiler_pic=
+lt_prog_compiler_static=
+
+
+  if test yes = "$GCC"; then
+    lt_prog_compiler_wl='-Wl,'
+    lt_prog_compiler_static='-static'
+
+    case $host_os in
+      aix*)
+      # All AIX code is PIC.
+      if test ia64 = "$host_cpu"; then
+	# AIX 5 now supports IA64 processor
+	lt_prog_compiler_static='-Bstatic'
+      fi
+      lt_prog_compiler_pic='-fPIC'
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            lt_prog_compiler_pic='-fPIC'
+        ;;
+      m68k)
+            # FIXME: we need at least 68020 code to build shared libraries, but
+            # adding the '-m68020' flag to GCC prevents building anything better,
+            # like '-m68040'.
+            lt_prog_compiler_pic='-m68020 -resident32 -malways-restore-a4'
+        ;;
+      esac
+      ;;
+
+    beos* | irix5* | irix6* | nonstopux* | osf3* | osf4* | osf5*)
+      # PIC is the default for these OSes.
+      ;;
+
+    mingw* | cygwin* | pw32* | os2* | cegcc*)
+      # This hack is so that the source file can tell whether it is being
+      # built for inclusion in a dll (and should export symbols for example).
+      # Although the cygwin gcc ignores -fPIC, still need this for old-style
+      # (--disable-auto-import) libraries
+      lt_prog_compiler_pic='-DDLL_EXPORT'
+      case $host_os in
+      os2*)
+	lt_prog_compiler_static='$wl-static'
+	;;
+      esac
+      ;;
+
+    darwin* | rhapsody*)
+      # PIC is the default on this platform
+      # Common symbols not allowed in MH_DYLIB files
+      lt_prog_compiler_pic='-fno-common'
+      ;;
+
+    haiku*)
+      # PIC is the default for Haiku.
+      # The "-static" flag exists, but is broken.
+      lt_prog_compiler_static=
+      ;;
+
+    hpux*)
+      # PIC is the default for 64-bit PA HP-UX, but not for 32-bit
+      # PA HP-UX.  On IA64 HP-UX, PIC is the default but the pic flag
+      # sets the default TLS model and affects inlining.
+      case $host_cpu in
+      hppa*64*)
+	# +Z the default
+	;;
+      *)
+	lt_prog_compiler_pic='-fPIC'
+	;;
+      esac
+      ;;
+
+    interix[3-9]*)
+      # Interix 3.x gcc -fpic/-fPIC options generate broken code.
+      # Instead, we relocate shared libraries at runtime.
+      ;;
+
+    msdosdjgpp*)
+      # Just because we use GCC doesn't mean we suddenly get shared libraries
+      # on systems that don't support them.
+      lt_prog_compiler_can_build_shared=no
+      enable_shared=no
+      ;;
+
+    *nto* | *qnx*)
+      # QNX uses GNU C++, but need to define -shared option too, otherwise
+      # it will coredump.
+      lt_prog_compiler_pic='-fPIC -shared'
+      ;;
+
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	lt_prog_compiler_pic=-Kconform_pic
+      fi
+      ;;
+
+    *)
+      lt_prog_compiler_pic='-fPIC'
+      ;;
+    esac
+
+    case $cc_basename in
+    nvcc*) # Cuda Compiler Driver 2.2
+      lt_prog_compiler_wl='-Xlinker '
+      if test -n "$lt_prog_compiler_pic"; then
+        lt_prog_compiler_pic="-Xcompiler $lt_prog_compiler_pic"
+      fi
+      ;;
+    esac
+  else
+    # PORTME Check for flag to pass linker flags through the system compiler.
+    case $host_os in
+    aix*)
+      lt_prog_compiler_wl='-Wl,'
+      if test ia64 = "$host_cpu"; then
+	# AIX 5 now supports IA64 processor
+	lt_prog_compiler_static='-Bstatic'
+      else
+	lt_prog_compiler_static='-bnso -bI:/lib/syscalls.exp'
+      fi
+      ;;
+
+    darwin* | rhapsody*)
+      # PIC is the default on this platform
+      # Common symbols not allowed in MH_DYLIB files
+      lt_prog_compiler_pic='-fno-common'
+      case $cc_basename in
+      nagfor*)
+        # NAG Fortran compiler
+        lt_prog_compiler_wl='-Wl,-Wl,,'
+        lt_prog_compiler_pic='-PIC'
+        lt_prog_compiler_static='-Bstatic'
+        ;;
+      esac
+      ;;
+
+    mingw* | cygwin* | pw32* | os2* | cegcc*)
+      # This hack is so that the source file can tell whether it is being
+      # built for inclusion in a dll (and should export symbols for example).
+      lt_prog_compiler_pic='-DDLL_EXPORT'
+      case $host_os in
+      os2*)
+	lt_prog_compiler_static='$wl-static'
+	;;
+      esac
+      ;;
+
+    hpux9* | hpux10* | hpux11*)
+      lt_prog_compiler_wl='-Wl,'
+      # PIC is the default for IA64 HP-UX and 64-bit HP-UX, but
+      # not for PA HP-UX.
+      case $host_cpu in
+      hppa*64*|ia64*)
+	# +Z the default
+	;;
+      *)
+	lt_prog_compiler_pic='+Z'
+	;;
+      esac
+      # Is there a better lt_prog_compiler_static that works with the bundled CC?
+      lt_prog_compiler_static='$wl-a ${wl}archive'
+      ;;
+
+    irix5* | irix6* | nonstopux*)
+      lt_prog_compiler_wl='-Wl,'
+      # PIC (with -KPIC) is the default.
+      lt_prog_compiler_static='-non_shared'
+      ;;
+
+    linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+      case $cc_basename in
+      # old Intel for x86_64, which still supported -KPIC.
+      ecc*)
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-KPIC'
+	lt_prog_compiler_static='-static'
+        ;;
+      # icc used to be incompatible with GCC.
+      # ICC 10 doesn't accept -KPIC any more.
+      icc* | ifort*)
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-fPIC'
+	lt_prog_compiler_static='-static'
+        ;;
+      # Lahey Fortran 8.1.
+      lf95*)
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='--shared'
+	lt_prog_compiler_static='--static'
+	;;
+      nagfor*)
+	# NAG Fortran compiler
+	lt_prog_compiler_wl='-Wl,-Wl,,'
+	lt_prog_compiler_pic='-PIC'
+	lt_prog_compiler_static='-Bstatic'
+	;;
+      tcc*)
+	# Fabrice Bellard et al's Tiny C Compiler
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-fPIC'
+	lt_prog_compiler_static='-static'
+	;;
+      pgcc* | pgf77* | pgf90* | pgf95* | pgfortran*)
+        # Portland Group compilers (*not* the Pentium gcc compiler,
+	# which looks to be a dead project)
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-fpic'
+	lt_prog_compiler_static='-Bstatic'
+        ;;
+      ccc*)
+        lt_prog_compiler_wl='-Wl,'
+        # All Alpha code is PIC.
+        lt_prog_compiler_static='-non_shared'
+        ;;
+      xl* | bgxl* | bgf* | mpixl*)
+	# IBM XL C 8.0/Fortran 10.1, 11.1 on PPC and BlueGene
+	lt_prog_compiler_wl='-Wl,'
+	lt_prog_compiler_pic='-qpic'
+	lt_prog_compiler_static='-qstaticlink'
+	;;
+      *)
+	case `$CC -V 2>&1 | $SED 5q` in
+	*Sun\ Ceres\ Fortran* | *Sun*Fortran*\ [1-7].* | *Sun*Fortran*\ 8.[0-3]*)
+	  # Sun Fortran 8.3 passes all unrecognized flags to the linker
+	  lt_prog_compiler_pic='-KPIC'
+	  lt_prog_compiler_static='-Bstatic'
+	  lt_prog_compiler_wl=''
+	  ;;
+	*Sun\ F* | *Sun*Fortran*)
+	  lt_prog_compiler_pic='-KPIC'
+	  lt_prog_compiler_static='-Bstatic'
+	  lt_prog_compiler_wl='-Qoption ld '
+	  ;;
+	*Sun\ C*)
+	  # Sun C 5.9
+	  lt_prog_compiler_pic='-KPIC'
+	  lt_prog_compiler_static='-Bstatic'
+	  lt_prog_compiler_wl='-Wl,'
+	  ;;
+        *Intel*\ [CF]*Compiler*)
+	  lt_prog_compiler_wl='-Wl,'
+	  lt_prog_compiler_pic='-fPIC'
+	  lt_prog_compiler_static='-static'
+	  ;;
+	*Portland\ Group*)
+	  lt_prog_compiler_wl='-Wl,'
+	  lt_prog_compiler_pic='-fpic'
+	  lt_prog_compiler_static='-Bstatic'
+	  ;;
+	esac
+	;;
+      esac
+      ;;
+
+    newsos6)
+      lt_prog_compiler_pic='-KPIC'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    *nto* | *qnx*)
+      # QNX uses GNU C++, but need to define -shared option too, otherwise
+      # it will coredump.
+      lt_prog_compiler_pic='-fPIC -shared'
+      ;;
+
+    osf3* | osf4* | osf5*)
+      lt_prog_compiler_wl='-Wl,'
+      # All OSF/1 code is PIC.
+      lt_prog_compiler_static='-non_shared'
+      ;;
+
+    rdos*)
+      lt_prog_compiler_static='-non_shared'
+      ;;
+
+    solaris*)
+      lt_prog_compiler_pic='-KPIC'
+      lt_prog_compiler_static='-Bstatic'
+      case $cc_basename in
+      f77* | f90* | f95* | sunf77* | sunf90* | sunf95*)
+	lt_prog_compiler_wl='-Qoption ld ';;
+      *)
+	lt_prog_compiler_wl='-Wl,';;
+      esac
+      ;;
+
+    sunos4*)
+      lt_prog_compiler_wl='-Qoption ld '
+      lt_prog_compiler_pic='-PIC'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    sysv4 | sysv4.2uw2* | sysv4.3*)
+      lt_prog_compiler_wl='-Wl,'
+      lt_prog_compiler_pic='-KPIC'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	lt_prog_compiler_pic='-Kconform_pic'
+	lt_prog_compiler_static='-Bstatic'
+      fi
+      ;;
+
+    sysv5* | unixware* | sco3.2v5* | sco5v6* | OpenUNIX*)
+      lt_prog_compiler_wl='-Wl,'
+      lt_prog_compiler_pic='-KPIC'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    unicos*)
+      lt_prog_compiler_wl='-Wl,'
+      lt_prog_compiler_can_build_shared=no
+      ;;
+
+    uts4*)
+      lt_prog_compiler_pic='-pic'
+      lt_prog_compiler_static='-Bstatic'
+      ;;
+
+    *)
+      lt_prog_compiler_can_build_shared=no
+      ;;
+    esac
+  fi
+
+case $host_os in
+  # For platforms that do not support PIC, -DPIC is meaningless:
+  *djgpp*)
+    lt_prog_compiler_pic=
+    ;;
+  *)
+    lt_prog_compiler_pic="$lt_prog_compiler_pic -DPIC"
+    ;;
+esac
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $compiler option to produce PIC" >&5
+printf %s "checking for $compiler option to produce PIC... " >&6; }
+if test ${lt_cv_prog_compiler_pic+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_prog_compiler_pic=$lt_prog_compiler_pic ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_pic" >&5
+printf "%s\n" "$lt_cv_prog_compiler_pic" >&6; }
+lt_prog_compiler_pic=$lt_cv_prog_compiler_pic
+
+#
+# Check to make sure the PIC flag actually works.
+#
+if test -n "$lt_prog_compiler_pic"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if $compiler PIC flag $lt_prog_compiler_pic works" >&5
+printf %s "checking if $compiler PIC flag $lt_prog_compiler_pic works... " >&6; }
+if test ${lt_cv_prog_compiler_pic_works+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_prog_compiler_pic_works=no
+   ac_outfile=conftest.$ac_objext
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+   lt_compiler_flag="$lt_prog_compiler_pic -DPIC"  ## exclude from sc_useless_quotes_in_assignment
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   # The option is referenced via a variable to avoid confusing sed.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&5)
+   (eval "$lt_compile" 2>conftest.err)
+   ac_status=$?
+   cat conftest.err >&5
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   if (exit $ac_status) && test -s "$ac_outfile"; then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings other than the usual output.
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' >conftest.exp
+     $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+     if test ! -s conftest.er2 || diff conftest.exp conftest.er2 >/dev/null; then
+       lt_cv_prog_compiler_pic_works=yes
+     fi
+   fi
+   $RM conftest*
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_pic_works" >&5
+printf "%s\n" "$lt_cv_prog_compiler_pic_works" >&6; }
+
+if test yes = "$lt_cv_prog_compiler_pic_works"; then
+    case $lt_prog_compiler_pic in
+     "" | " "*) ;;
+     *) lt_prog_compiler_pic=" $lt_prog_compiler_pic" ;;
+     esac
+else
+    lt_prog_compiler_pic=
+     lt_prog_compiler_can_build_shared=no
+fi
+
+fi
+
+
+
+
+
+
+
+
+
+
+
+#
+# Check to make sure the static flag actually works.
+#
+wl=$lt_prog_compiler_wl eval lt_tmp_static_flag=\"$lt_prog_compiler_static\"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if $compiler static flag $lt_tmp_static_flag works" >&5
+printf %s "checking if $compiler static flag $lt_tmp_static_flag works... " >&6; }
+if test ${lt_cv_prog_compiler_static_works+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_prog_compiler_static_works=no
+   save_LDFLAGS=$LDFLAGS
+   LDFLAGS="$LDFLAGS $lt_tmp_static_flag"
+   echo "$lt_simple_link_test_code" > conftest.$ac_ext
+   if (eval $ac_link 2>conftest.err) && test -s conftest$ac_exeext; then
+     # The linker can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     if test -s conftest.err; then
+       # Append any errors to the config.log.
+       cat conftest.err 1>&5
+       $ECHO "$_lt_linker_boilerplate" | $SED '/^$/d' > conftest.exp
+       $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+       if diff conftest.exp conftest.er2 >/dev/null; then
+         lt_cv_prog_compiler_static_works=yes
+       fi
+     else
+       lt_cv_prog_compiler_static_works=yes
+     fi
+   fi
+   $RM -r conftest*
+   LDFLAGS=$save_LDFLAGS
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_static_works" >&5
+printf "%s\n" "$lt_cv_prog_compiler_static_works" >&6; }
+
+if test yes = "$lt_cv_prog_compiler_static_works"; then
+    :
+else
+    lt_prog_compiler_static=
+fi
+
+
+
+
+
+
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if $compiler supports -c -o file.$ac_objext" >&5
+printf %s "checking if $compiler supports -c -o file.$ac_objext... " >&6; }
+if test ${lt_cv_prog_compiler_c_o+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_prog_compiler_c_o=no
+   $RM -r conftest 2>/dev/null
+   mkdir conftest
+   cd conftest
+   mkdir out
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+
+   lt_compiler_flag="-o out/conftest2.$ac_objext"
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&5)
+   (eval "$lt_compile" 2>out/conftest.err)
+   ac_status=$?
+   cat out/conftest.err >&5
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   if (exit $ac_status) && test -s out/conftest2.$ac_objext
+   then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' > out/conftest.exp
+     $SED '/^$/d; /^ *+/d' out/conftest.err >out/conftest.er2
+     if test ! -s out/conftest.er2 || diff out/conftest.exp out/conftest.er2 >/dev/null; then
+       lt_cv_prog_compiler_c_o=yes
+     fi
+   fi
+   chmod u+w . 2>&5
+   $RM conftest*
+   # SGI C++ compiler will create directory out/ii_files/ for
+   # template instantiation
+   test -d out/ii_files && $RM out/ii_files/* && rmdir out/ii_files
+   $RM out/* && rmdir out
+   cd ..
+   $RM -r conftest
+   $RM conftest*
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_c_o" >&5
+printf "%s\n" "$lt_cv_prog_compiler_c_o" >&6; }
+
+
+
+
+
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if $compiler supports -c -o file.$ac_objext" >&5
+printf %s "checking if $compiler supports -c -o file.$ac_objext... " >&6; }
+if test ${lt_cv_prog_compiler_c_o+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_prog_compiler_c_o=no
+   $RM -r conftest 2>/dev/null
+   mkdir conftest
+   cd conftest
+   mkdir out
+   echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+
+   lt_compiler_flag="-o out/conftest2.$ac_objext"
+   # Insert the option either (1) after the last *FLAGS variable, or
+   # (2) before a word containing "conftest.", or (3) at the end.
+   # Note that $ac_compile itself does not contain backslashes and begins
+   # with a dollar sign (not a hyphen), so the echo should work correctly.
+   lt_compile=`echo "$ac_compile" | $SED \
+   -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
+   -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
+   -e 's:$: $lt_compiler_flag:'`
+   (eval echo "\"\$as_me:$LINENO: $lt_compile\"" >&5)
+   (eval "$lt_compile" 2>out/conftest.err)
+   ac_status=$?
+   cat out/conftest.err >&5
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   if (exit $ac_status) && test -s out/conftest2.$ac_objext
+   then
+     # The compiler can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     $ECHO "$_lt_compiler_boilerplate" | $SED '/^$/d' > out/conftest.exp
+     $SED '/^$/d; /^ *+/d' out/conftest.err >out/conftest.er2
+     if test ! -s out/conftest.er2 || diff out/conftest.exp out/conftest.er2 >/dev/null; then
+       lt_cv_prog_compiler_c_o=yes
+     fi
+   fi
+   chmod u+w . 2>&5
+   $RM conftest*
+   # SGI C++ compiler will create directory out/ii_files/ for
+   # template instantiation
+   test -d out/ii_files && $RM out/ii_files/* && rmdir out/ii_files
+   $RM out/* && rmdir out
+   cd ..
+   $RM -r conftest
+   $RM conftest*
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler_c_o" >&5
+printf "%s\n" "$lt_cv_prog_compiler_c_o" >&6; }
+
+
+
+
+hard_links=nottested
+if test no = "$lt_cv_prog_compiler_c_o" && test no != "$need_locks"; then
+  # do not overwrite the value of need_locks provided by the user
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we can lock with hard links" >&5
+printf %s "checking if we can lock with hard links... " >&6; }
+  hard_links=yes
+  $RM conftest*
+  ln conftest.a conftest.b 2>/dev/null && hard_links=no
+  touch conftest.a
+  ln conftest.a conftest.b 2>&5 || hard_links=no
+  ln conftest.a conftest.b 2>/dev/null && hard_links=no
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $hard_links" >&5
+printf "%s\n" "$hard_links" >&6; }
+  if test no = "$hard_links"; then
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: '$CC' does not support '-c -o', so 'make -j' may be unsafe" >&5
+printf "%s\n" "$as_me: WARNING: '$CC' does not support '-c -o', so 'make -j' may be unsafe" >&2;}
+    need_locks=warn
+  fi
+else
+  need_locks=no
+fi
+
+
+
+
+
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the $compiler linker ($LD) supports shared libraries" >&5
+printf %s "checking whether the $compiler linker ($LD) supports shared libraries... " >&6; }
+
+  runpath_var=
+  allow_undefined_flag=
+  always_export_symbols=no
+  archive_cmds=
+  archive_expsym_cmds=
+  compiler_needs_object=no
+  enable_shared_with_static_runtimes=no
+  export_dynamic_flag_spec=
+  export_symbols_cmds='$NM $libobjs $convenience | $global_symbol_pipe | $SED '\''s/.* //'\'' | sort | uniq > $export_symbols'
+  hardcode_automatic=no
+  hardcode_direct=no
+  hardcode_direct_absolute=no
+  hardcode_libdir_flag_spec=
+  hardcode_libdir_separator=
+  hardcode_minus_L=no
+  hardcode_shlibpath_var=unsupported
+  inherit_rpath=no
+  link_all_deplibs=unknown
+  module_cmds=
+  module_expsym_cmds=
+  old_archive_from_new_cmds=
+  old_archive_from_expsyms_cmds=
+  thread_safe_flag_spec=
+  whole_archive_flag_spec=
+  # include_expsyms should be a list of space-separated symbols to be *always*
+  # included in the symbol list
+  include_expsyms=
+  # exclude_expsyms can be an extended regexp of symbols to exclude
+  # it will be wrapped by ' (' and ')$', so one must not match beginning or
+  # end of line.  Example: 'a|bc|.*d.*' will exclude the symbols 'a' and 'bc',
+  # as well as any symbol that contains 'd'.
+  exclude_expsyms='_GLOBAL_OFFSET_TABLE_|_GLOBAL__F[ID]_.*'
+  # Although _GLOBAL_OFFSET_TABLE_ is a valid symbol C name, most a.out
+  # platforms (ab)use it in PIC code, but their linkers get confused if
+  # the symbol is explicitly referenced.  Since portable code cannot
+  # rely on this symbol name, it's probably fine to never include it in
+  # preloaded symbol tables.
+  # Exclude shared library initialization/finalization symbols.
+  extract_expsyms_cmds=
+
+  case $host_os in
+  cygwin* | mingw* | pw32* | cegcc*)
+    # FIXME: the MSVC++ and ICC port hasn't been tested in a loooong time
+    # When not using gcc, we currently assume that we are using
+    # Microsoft Visual C++ or Intel C++ Compiler.
+    if test yes != "$GCC"; then
+      with_gnu_ld=no
+    fi
+    ;;
+  interix*)
+    # we just hope/assume this is gcc and not c89 (= MSVC++ or ICC)
+    with_gnu_ld=yes
+    ;;
+  openbsd* | bitrig*)
+    with_gnu_ld=no
+    ;;
+  esac
+
+  ld_shlibs=yes
+
+  # On some targets, GNU ld is compatible enough with the native linker
+  # that we're better off using the native interface for both.
+  lt_use_gnu_ld_interface=no
+  if test yes = "$with_gnu_ld"; then
+    case $host_os in
+      aix*)
+	# The AIX port of GNU ld has always aspired to compatibility
+	# with the native linker.  However, as the warning in the GNU ld
+	# block says, versions before 2.19.5* couldn't really create working
+	# shared libraries, regardless of the interface used.
+	case `$LD -v 2>&1` in
+	  *\ \(GNU\ Binutils\)\ 2.19.5*) ;;
+	  *\ \(GNU\ Binutils\)\ 2.[2-9]*) ;;
+	  *\ \(GNU\ Binutils\)\ [3-9]*) ;;
+	  *)
+	    lt_use_gnu_ld_interface=yes
+	    ;;
+	esac
+	;;
+      *)
+	lt_use_gnu_ld_interface=yes
+	;;
+    esac
+  fi
+
+  if test yes = "$lt_use_gnu_ld_interface"; then
+    # If archive_cmds runs LD, not CC, wlarc should be empty
+    wlarc='$wl'
+
+    # Set some defaults for GNU ld with shared library support. These
+    # are reset later if shared libraries are not supported. Putting them
+    # here allows them to be overridden if necessary.
+    runpath_var=LD_RUN_PATH
+    hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+    export_dynamic_flag_spec='$wl--export-dynamic'
+    # ancient GNU ld didn't support --whole-archive et. al.
+    if $LD --help 2>&1 | $GREP 'no-whole-archive' > /dev/null; then
+      whole_archive_flag_spec=$wlarc'--whole-archive$convenience '$wlarc'--no-whole-archive'
+    else
+      whole_archive_flag_spec=
+    fi
+    supports_anon_versioning=no
+    case `$LD -v | $SED -e 's/([^)]\+)\s\+//' 2>&1` in
+      *GNU\ gold*) supports_anon_versioning=yes ;;
+      *\ [01].* | *\ 2.[0-9].* | *\ 2.10.*) ;; # catch versions < 2.11
+      *\ 2.11.93.0.2\ *) supports_anon_versioning=yes ;; # RH7.3 ...
+      *\ 2.11.92.0.12\ *) supports_anon_versioning=yes ;; # Mandrake 8.2 ...
+      *\ 2.11.*) ;; # other 2.11 versions
+      *) supports_anon_versioning=yes ;;
+    esac
+
+    # See if GNU ld supports shared libraries.
+    case $host_os in
+    aix[3-9]*)
+      # On AIX/PPC, the GNU linker is very broken
+      if test ia64 != "$host_cpu"; then
+	ld_shlibs=no
+	cat <<_LT_EOF 1>&2
+
+*** Warning: the GNU linker, at least up to release 2.19, is reported
+*** to be unable to reliably create shared libraries on AIX.
+*** Therefore, libtool is disabling shared libraries support.  If you
+*** really care for shared libraries, you may want to install binutils
+*** 2.20 or above, or modify your PATH so that a non-GNU linker is found.
+*** You will then need to restart the configuration process.
+
+_LT_EOF
+      fi
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+            archive_expsym_cmds=''
+        ;;
+      m68k)
+            archive_cmds='$RM $output_objdir/a2ixlibrary.data~$ECHO "#define NAME $libname" > $output_objdir/a2ixlibrary.data~$ECHO "#define LIBRARY_ID 1" >> $output_objdir/a2ixlibrary.data~$ECHO "#define VERSION $major" >> $output_objdir/a2ixlibrary.data~$ECHO "#define REVISION $revision" >> $output_objdir/a2ixlibrary.data~$AR $AR_FLAGS $lib $libobjs~$RANLIB $lib~(cd $output_objdir && a2ixlibrary -32)'
+            hardcode_libdir_flag_spec='-L$libdir'
+            hardcode_minus_L=yes
+        ;;
+      esac
+      ;;
+
+    beos*)
+      if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	allow_undefined_flag=unsupported
+	# Joseph Beckenbach <jrb3@best.com> says some releases of gcc
+	# support --undefined.  This deserves some investigation.  FIXME
+	archive_cmds='$CC -nostart $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+      else
+	ld_shlibs=no
+      fi
+      ;;
+
+    cygwin* | mingw* | pw32* | cegcc*)
+      # _LT_TAGVAR(hardcode_libdir_flag_spec, ) is actually meaningless,
+      # as there is no search path for DLLs.
+      hardcode_libdir_flag_spec='-L$libdir'
+      export_dynamic_flag_spec='$wl--export-all-symbols'
+      allow_undefined_flag=unsupported
+      always_export_symbols=no
+      enable_shared_with_static_runtimes=yes
+      export_symbols_cmds='$NM $libobjs $convenience | $global_symbol_pipe | $SED -e '\''/^[BCDGRS][ ]/s/.*[ ]\([^ ]*\)/\1 DATA/;s/^.*[ ]__nm__\([^ ]*\)[ ][^ ]*/\1 DATA/;/^I[ ]/d;/^[AITW][ ]/s/.* //'\'' | sort | uniq > $export_symbols'
+      exclude_expsyms='[_]+GLOBAL_OFFSET_TABLE_|[_]+GLOBAL__[FID]_.*|[_]+head_[A-Za-z0-9_]+_dll|[A-Za-z0-9_]+_dll_iname'
+
+      if $LD --help 2>&1 | $GREP 'auto-import' > /dev/null; then
+        archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
+	# If the export-symbols file already is a .def file, use it as
+	# is; otherwise, prepend EXPORTS...
+	archive_expsym_cmds='if   test DEF = "`$SED -n     -e '\''s/^[	 ]*//'\''     -e '\''/^\(;.*\)*$/d'\''     -e '\''s/^\(EXPORTS\|LIBRARY\)\([	 ].*\)*$/DEF/p'\''     -e q     $export_symbols`" ; then
+          cp $export_symbols $output_objdir/$soname.def;
+        else
+          echo EXPORTS > $output_objdir/$soname.def;
+          cat $export_symbols >> $output_objdir/$soname.def;
+        fi~
+        $CC -shared $output_objdir/$soname.def $libobjs $deplibs $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
+      else
+	ld_shlibs=no
+      fi
+      ;;
+
+    haiku*)
+      archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+      link_all_deplibs=yes
+      ;;
+
+    os2*)
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_minus_L=yes
+      allow_undefined_flag=unsupported
+      shrext_cmds=.dll
+      archive_cmds='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	emxexp $libobjs | $SED /"_DLL_InitTerm"/d >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      archive_expsym_cmds='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	prefix_cmds="$SED"~
+	if test EXPORTS = "`$SED 1q $export_symbols`"; then
+	  prefix_cmds="$prefix_cmds -e 1d";
+	fi~
+	prefix_cmds="$prefix_cmds -e \"s/^\(.*\)$/_\1/g\""~
+	cat $export_symbols | $prefix_cmds >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      old_archive_From_new_cmds='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
+      enable_shared_with_static_runtimes=yes
+      file_list_spec='@'
+      ;;
+
+    interix[3-9]*)
+      hardcode_direct=no
+      hardcode_shlibpath_var=no
+      hardcode_libdir_flag_spec='$wl-rpath,$libdir'
+      export_dynamic_flag_spec='$wl-E'
+      # Hack: On Interix 3.x, we cannot compile PIC because of a broken gcc.
+      # Instead, shared libraries are loaded at an image base (0x10000000 by
+      # default) and relocated if they conflict, which is a slow very memory
+      # consuming and fragmenting process.  To avoid this, we pick a random,
+      # 256 KiB-aligned image base between 0x50000000 and 0x6FFC0000 at link
+      # time.  Moving up from 0x10000000 also allows more sbrk(2) space.
+      archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-h,$soname $wl--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
+      archive_expsym_cmds='$SED "s|^|_|" $export_symbols >$output_objdir/$soname.expsym~$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-h,$soname $wl--retain-symbols-file,$output_objdir/$soname.expsym $wl--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
+      ;;
+
+    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu)
+      tmp_diet=no
+      if test linux-dietlibc = "$host_os"; then
+	case $cc_basename in
+	  diet\ *) tmp_diet=yes;;	# linux-dietlibc with static linking (!diet-dyn)
+	esac
+      fi
+      if $LD --help 2>&1 | $EGREP ': supported targets:.* elf' > /dev/null \
+	 && test no = "$tmp_diet"
+      then
+	tmp_addflag=' $pic_flag'
+	tmp_sharedflag='-shared'
+	case $cc_basename,$host_cpu in
+        pgcc*)				# Portland Group C compiler
+	  whole_archive_flag_spec='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  tmp_addflag=' $pic_flag'
+	  ;;
+	pgf77* | pgf90* | pgf95* | pgfortran*)
+					# Portland Group f77 and f90 compilers
+	  whole_archive_flag_spec='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  tmp_addflag=' $pic_flag -Mnomain' ;;
+	ecc*,ia64* | icc*,ia64*)	# Intel C compiler on ia64
+	  tmp_addflag=' -i_dynamic' ;;
+	efc*,ia64* | ifort*,ia64*)	# Intel Fortran compiler on ia64
+	  tmp_addflag=' -i_dynamic -nofor_main' ;;
+	ifc* | ifort*)			# Intel Fortran compiler
+	  tmp_addflag=' -nofor_main' ;;
+	lf95*)				# Lahey Fortran 8.1
+	  whole_archive_flag_spec=
+	  tmp_sharedflag='--shared' ;;
+        nagfor*)                        # NAGFOR 5.3
+          tmp_sharedflag='-Wl,-shared' ;;
+	xl[cC]* | bgxl[cC]* | mpixl[cC]*) # IBM XL C 8.0 on PPC (deal with xlf below)
+	  tmp_sharedflag='-qmkshrobj'
+	  tmp_addflag= ;;
+	nvcc*)	# Cuda Compiler Driver 2.2
+	  whole_archive_flag_spec='$wl--whole-archive`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  compiler_needs_object=yes
+	  ;;
+	esac
+	case `$CC -V 2>&1 | $SED 5q` in
+	*Sun\ C*)			# Sun C 5.9
+	  whole_archive_flag_spec='$wl--whole-archive`new_convenience=; for conv in $convenience\"\"; do test -z \"$conv\" || new_convenience=\"$new_convenience,$conv\"; done; func_echo_all \"$new_convenience\"` $wl--no-whole-archive'
+	  compiler_needs_object=yes
+	  tmp_sharedflag='-G' ;;
+	*Sun\ F*)			# Sun Fortran 8.3
+	  tmp_sharedflag='-G' ;;
+	esac
+	archive_cmds='$CC '"$tmp_sharedflag""$tmp_addflag"' $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+
+        if test yes = "$supports_anon_versioning"; then
+          archive_expsym_cmds='echo "{ global:" > $output_objdir/$libname.ver~
+            cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $output_objdir/$libname.ver~
+            echo "local: *; };" >> $output_objdir/$libname.ver~
+            $CC '"$tmp_sharedflag""$tmp_addflag"' $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-version-script $wl$output_objdir/$libname.ver -o $lib'
+        fi
+
+	case $cc_basename in
+	tcc*)
+	  export_dynamic_flag_spec='-rdynamic'
+	  ;;
+	xlf* | bgf* | bgxlf* | mpixlf*)
+	  # IBM XL Fortran 10.1 on PPC cannot create shared libs itself
+	  whole_archive_flag_spec='--whole-archive$convenience --no-whole-archive'
+	  hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+	  archive_cmds='$LD -shared $libobjs $deplibs $linker_flags -soname $soname -o $lib'
+	  if test yes = "$supports_anon_versioning"; then
+	    archive_expsym_cmds='echo "{ global:" > $output_objdir/$libname.ver~
+              cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $output_objdir/$libname.ver~
+              echo "local: *; };" >> $output_objdir/$libname.ver~
+              $LD -shared $libobjs $deplibs $linker_flags -soname $soname -version-script $output_objdir/$libname.ver -o $lib'
+	  fi
+	  ;;
+	esac
+      else
+        ld_shlibs=no
+      fi
+      ;;
+
+    netbsd*)
+      if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+	archive_cmds='$LD -Bshareable $libobjs $deplibs $linker_flags -o $lib'
+	wlarc=
+      else
+	archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	archive_expsym_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+      fi
+      ;;
+
+    solaris*)
+      if $LD -v 2>&1 | $GREP 'BFD 2\.8' > /dev/null; then
+	ld_shlibs=no
+	cat <<_LT_EOF 1>&2
+
+*** Warning: The releases 2.8.* of the GNU linker cannot reliably
+*** create shared libraries on Solaris systems.  Therefore, libtool
+*** is disabling shared libraries support.  We urge you to upgrade GNU
+*** binutils to release 2.9.1 or newer.  Another option is to modify
+*** your PATH or compiler configuration so that the native linker is
+*** used, and then restart.
+
+_LT_EOF
+      elif $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	archive_expsym_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+      else
+	ld_shlibs=no
+      fi
+      ;;
+
+    sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX*)
+      case `$LD -v 2>&1` in
+        *\ [01].* | *\ 2.[0-9].* | *\ 2.1[0-5].*)
+	ld_shlibs=no
+	cat <<_LT_EOF 1>&2
+
+*** Warning: Releases of the GNU linker prior to 2.16.91.0.3 cannot
+*** reliably create shared libraries on SCO systems.  Therefore, libtool
+*** is disabling shared libraries support.  We urge you to upgrade GNU
+*** binutils to release 2.16.91.0.3 or newer.  Another option is to modify
+*** your PATH or compiler configuration so that the native linker is
+*** used, and then restart.
+
+_LT_EOF
+	;;
+	*)
+	  # For security reasons, it is highly recommended that you always
+	  # use absolute paths for naming shared libraries, and exclude the
+	  # DT_RUNPATH tag from executables and libraries.  But doing so
+	  # requires that you compile everything twice, which is a pain.
+	  if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	    hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+	    archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	    archive_expsym_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+	  else
+	    ld_shlibs=no
+	  fi
+	;;
+      esac
+      ;;
+
+    sunos4*)
+      archive_cmds='$LD -assert pure-text -Bshareable -o $lib $libobjs $deplibs $linker_flags'
+      wlarc=
+      hardcode_direct=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    *)
+      if $LD --help 2>&1 | $GREP ': supported targets:.* elf' > /dev/null; then
+	archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+	archive_expsym_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+      else
+	ld_shlibs=no
+      fi
+      ;;
+    esac
+
+    if test no = "$ld_shlibs"; then
+      runpath_var=
+      hardcode_libdir_flag_spec=
+      export_dynamic_flag_spec=
+      whole_archive_flag_spec=
+    fi
+  else
+    # PORTME fill in a description of your system's linker (not GNU ld)
+    case $host_os in
+    aix3*)
+      allow_undefined_flag=unsupported
+      always_export_symbols=yes
+      archive_expsym_cmds='$LD -o $output_objdir/$soname $libobjs $deplibs $linker_flags -bE:$export_symbols -T512 -H512 -bM:SRE~$AR $AR_FLAGS $lib $output_objdir/$soname'
+      # Note: this linker hardcodes the directories in LIBPATH if there
+      # are no directories specified by -L.
+      hardcode_minus_L=yes
+      if test yes = "$GCC" && test -z "$lt_prog_compiler_static"; then
+	# Neither direct hardcoding nor static linking is supported with a
+	# broken collect2.
+	hardcode_direct=unsupported
+      fi
+      ;;
+
+    aix[4-9]*)
+      if test ia64 = "$host_cpu"; then
+	# On IA64, the linker does run time linking by default, so we don't
+	# have to do anything special.
+	aix_use_runtimelinking=no
+	exp_sym_flag='-Bexport'
+	no_entry_flag=
+      else
+	# If we're using GNU nm, then we don't want the "-C" option.
+	# -C means demangle to GNU nm, but means don't demangle to AIX nm.
+	# Without the "-l" option, or with the "-B" option, AIX nm treats
+	# weak defined symbols like other global defined symbols, whereas
+	# GNU nm marks them as "W".
+	# While the 'weak' keyword is ignored in the Export File, we need
+	# it in the Import File for the 'aix-soname' feature, so we have
+	# to replace the "-B" option with "-P" for AIX nm.
+	if $NM -V 2>&1 | $GREP 'GNU' > /dev/null; then
+	  export_symbols_cmds='$NM -Bpg $libobjs $convenience | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "W")) && (substr(\$ 3,1,1) != ".")) { if (\$ 2 == "W") { print \$ 3 " weak" } else { print \$ 3 } } }'\'' | sort -u > $export_symbols'
+	else
+	  export_symbols_cmds='`func_echo_all $NM | $SED -e '\''s/B\([^B]*\)$/P\1/'\''` -PCpgl $libobjs $convenience | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "L") || (\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) && (substr(\$ 1,1,1) != ".")) { if ((\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) { print \$ 1 " weak" } else { print \$ 1 } } }'\'' | sort -u > $export_symbols'
+	fi
+	aix_use_runtimelinking=no
+
+	# Test if we are trying to use run time linking or normal
+	# AIX style linking. If -brtl is somewhere in LDFLAGS, we
+	# have runtime linking enabled, and use it for executables.
+	# For shared libraries, we enable/disable runtime linking
+	# depending on the kind of the shared library created -
+	# when "with_aix_soname,aix_use_runtimelinking" is:
+	# "aix,no"   lib.a(lib.so.V) shared, rtl:no,  for executables
+	# "aix,yes"  lib.so          shared, rtl:yes, for executables
+	#            lib.a           static archive
+	# "both,no"  lib.so.V(shr.o) shared, rtl:yes
+	#            lib.a(lib.so.V) shared, rtl:no,  for executables
+	# "both,yes" lib.so.V(shr.o) shared, rtl:yes, for executables
+	#            lib.a(lib.so.V) shared, rtl:no
+	# "svr4,*"   lib.so.V(shr.o) shared, rtl:yes, for executables
+	#            lib.a           static archive
+	case $host_os in aix4.[23]|aix4.[23].*|aix[5-9]*)
+	  for ld_flag in $LDFLAGS; do
+	  if (test x-brtl = "x$ld_flag" || test x-Wl,-brtl = "x$ld_flag"); then
+	    aix_use_runtimelinking=yes
+	    break
+	  fi
+	  done
+	  if test svr4,no = "$with_aix_soname,$aix_use_runtimelinking"; then
+	    # With aix-soname=svr4, we create the lib.so.V shared archives only,
+	    # so we don't have lib.a shared libs to link our executables.
+	    # We have to force runtime linking in this case.
+	    aix_use_runtimelinking=yes
+	    LDFLAGS="$LDFLAGS -Wl,-brtl"
+	  fi
+	  ;;
+	esac
+
+	exp_sym_flag='-bexport'
+	no_entry_flag='-bnoentry'
+      fi
+
+      # When large executables or shared objects are built, AIX ld can
+      # have problems creating the table of contents.  If linking a library
+      # or program results in "error TOC overflow" add -mminimal-toc to
+      # CXXFLAGS/CFLAGS for g++/gcc.  In the cases where that is not
+      # enough to fix the problem, add -Wl,-bbigtoc to LDFLAGS.
+
+      archive_cmds=''
+      hardcode_direct=yes
+      hardcode_direct_absolute=yes
+      hardcode_libdir_separator=':'
+      link_all_deplibs=yes
+      file_list_spec='$wl-f,'
+      case $with_aix_soname,$aix_use_runtimelinking in
+      aix,*) ;; # traditional, no import file
+      svr4,* | *,yes) # use import file
+	# The Import File defines what to hardcode.
+	hardcode_direct=no
+	hardcode_direct_absolute=no
+	;;
+      esac
+
+      if test yes = "$GCC"; then
+	case $host_os in aix4.[012]|aix4.[012].*)
+	# We only want to do this on AIX 4.2 and lower, the check
+	# below for broken collect2 doesn't work under 4.3+
+	  collect2name=`$CC -print-prog-name=collect2`
+	  if test -f "$collect2name" &&
+	   strings "$collect2name" | $GREP resolve_lib_name >/dev/null
+	  then
+	  # We have reworked collect2
+	  :
+	  else
+	  # We have old collect2
+	  hardcode_direct=unsupported
+	  # It fails to find uninstalled libraries when the uninstalled
+	  # path is not listed in the libpath.  Setting hardcode_minus_L
+	  # to unsupported forces relinking
+	  hardcode_minus_L=yes
+	  hardcode_libdir_flag_spec='-L$libdir'
+	  hardcode_libdir_separator=
+	  fi
+	  ;;
+	esac
+	shared_flag='-shared'
+	if test yes = "$aix_use_runtimelinking"; then
+	  shared_flag="$shared_flag "'$wl-G'
+	fi
+	# Need to ensure runtime linking is disabled for the traditional
+	# shared library, or the linker may eventually find shared libraries
+	# /with/ Import File - we do not want to mix them.
+	shared_flag_aix='-shared'
+	shared_flag_svr4='-shared $wl-G'
+      else
+	# not using gcc
+	if test ia64 = "$host_cpu"; then
+	# VisualAge C++, Version 5.5 for AIX 5L for IA-64, Beta 3 Release
+	# chokes on -Wl,-G. The following line is correct:
+	  shared_flag='-G'
+	else
+	  if test yes = "$aix_use_runtimelinking"; then
+	    shared_flag='$wl-G'
+	  else
+	    shared_flag='$wl-bM:SRE'
+	  fi
+	  shared_flag_aix='$wl-bM:SRE'
+	  shared_flag_svr4='$wl-G'
+	fi
+      fi
+
+      export_dynamic_flag_spec='$wl-bexpall'
+      # It seems that -bexpall does not export symbols beginning with
+      # underscore (_), so it is better to generate a list of symbols to export.
+      always_export_symbols=yes
+      if test aix,yes = "$with_aix_soname,$aix_use_runtimelinking"; then
+	# Warning - without using the other runtime loading flags (-brtl),
+	# -berok will link without error, but may produce a broken library.
+	allow_undefined_flag='-berok'
+        # Determine the default libpath from the value encoded in an
+        # empty executable.
+        if test set = "${lt_cv_aix_libpath+set}"; then
+  aix_libpath=$lt_cv_aix_libpath
+else
+  if test ${lt_cv_aix_libpath_+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+
+  lt_aix_libpath_sed='
+      /Import File Strings/,/^$/ {
+	  /^0/ {
+	      s/^0  *\([^ ]*\) *$/\1/
+	      p
+	  }
+      }'
+  lt_cv_aix_libpath_=`dump -H conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  # Check for a 64-bit object if we didn't find anything.
+  if test -z "$lt_cv_aix_libpath_"; then
+    lt_cv_aix_libpath_=`dump -HX64 conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  fi
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+  if test -z "$lt_cv_aix_libpath_"; then
+    lt_cv_aix_libpath_=/usr/lib:/lib
+  fi
+   ;;
+esac
+fi
+
+  aix_libpath=$lt_cv_aix_libpath_
+fi
+
+        hardcode_libdir_flag_spec='$wl-blibpath:$libdir:'"$aix_libpath"
+        archive_expsym_cmds='$CC -o $output_objdir/$soname $libobjs $deplibs $wl'$no_entry_flag' $compiler_flags `if test -n "$allow_undefined_flag"; then func_echo_all "$wl$allow_undefined_flag"; else :; fi` $wl'$exp_sym_flag:\$export_symbols' '$shared_flag
+      else
+	if test ia64 = "$host_cpu"; then
+	  hardcode_libdir_flag_spec='$wl-R $libdir:/usr/lib:/lib'
+	  allow_undefined_flag="-z nodefs"
+	  archive_expsym_cmds="\$CC $shared_flag"' -o $output_objdir/$soname $libobjs $deplibs '"\$wl$no_entry_flag"' $compiler_flags $wl$allow_undefined_flag '"\$wl$exp_sym_flag:\$export_symbols"
+	else
+	 # Determine the default libpath from the value encoded in an
+	 # empty executable.
+	 if test set = "${lt_cv_aix_libpath+set}"; then
+  aix_libpath=$lt_cv_aix_libpath
+else
+  if test ${lt_cv_aix_libpath_+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+
+  lt_aix_libpath_sed='
+      /Import File Strings/,/^$/ {
+	  /^0/ {
+	      s/^0  *\([^ ]*\) *$/\1/
+	      p
+	  }
+      }'
+  lt_cv_aix_libpath_=`dump -H conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  # Check for a 64-bit object if we didn't find anything.
+  if test -z "$lt_cv_aix_libpath_"; then
+    lt_cv_aix_libpath_=`dump -HX64 conftest$ac_exeext 2>/dev/null | $SED -n -e "$lt_aix_libpath_sed"`
+  fi
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+  if test -z "$lt_cv_aix_libpath_"; then
+    lt_cv_aix_libpath_=/usr/lib:/lib
+  fi
+   ;;
+esac
+fi
+
+  aix_libpath=$lt_cv_aix_libpath_
+fi
+
+	 hardcode_libdir_flag_spec='$wl-blibpath:$libdir:'"$aix_libpath"
+	  # Warning - without using the other run time loading flags,
+	  # -berok will link without error, but may produce a broken library.
+	  no_undefined_flag=' $wl-bernotok'
+	  allow_undefined_flag=' $wl-berok'
+	  if test yes = "$with_gnu_ld"; then
+	    # We only use this code for GNU lds that support --whole-archive.
+	    whole_archive_flag_spec='$wl--whole-archive$convenience $wl--no-whole-archive'
+	  else
+	    # Exported symbols can be pulled into shared objects from archives
+	    whole_archive_flag_spec='$convenience'
+	  fi
+	  archive_cmds_need_lc=yes
+	  archive_expsym_cmds='$RM -r $output_objdir/$realname.d~$MKDIR $output_objdir/$realname.d'
+	  # -brtl affects multiple linker settings, -berok does not and is overridden later
+	  compiler_flags_filtered='`func_echo_all "$compiler_flags " | $SED -e "s%-brtl\\([, ]\\)%-berok\\1%g"`'
+	  if test svr4 != "$with_aix_soname"; then
+	    # This is similar to how AIX traditionally builds its shared libraries.
+	    archive_expsym_cmds="$archive_expsym_cmds"'~$CC '$shared_flag_aix' -o $output_objdir/$realname.d/$soname $libobjs $deplibs $wl-bnoentry '$compiler_flags_filtered'$wl-bE:$export_symbols$allow_undefined_flag~$AR $AR_FLAGS $output_objdir/$libname$release.a $output_objdir/$realname.d/$soname'
+	  fi
+	  if test aix != "$with_aix_soname"; then
+	    archive_expsym_cmds="$archive_expsym_cmds"'~$CC '$shared_flag_svr4' -o $output_objdir/$realname.d/$shared_archive_member_spec.o $libobjs $deplibs $wl-bnoentry '$compiler_flags_filtered'$wl-bE:$export_symbols$allow_undefined_flag~$STRIP -e $output_objdir/$realname.d/$shared_archive_member_spec.o~( func_echo_all "#! $soname($shared_archive_member_spec.o)"; if test shr_64 = "$shared_archive_member_spec"; then func_echo_all "# 64"; else func_echo_all "# 32"; fi; cat $export_symbols ) > $output_objdir/$realname.d/$shared_archive_member_spec.imp~$AR $AR_FLAGS $output_objdir/$soname $output_objdir/$realname.d/$shared_archive_member_spec.o $output_objdir/$realname.d/$shared_archive_member_spec.imp'
+	  else
+	    # used by -dlpreopen to get the symbols
+	    archive_expsym_cmds="$archive_expsym_cmds"'~$MV  $output_objdir/$realname.d/$soname $output_objdir'
+	  fi
+	  archive_expsym_cmds="$archive_expsym_cmds"'~$RM -r $output_objdir/$realname.d'
+	fi
+      fi
+      ;;
+
+    amigaos*)
+      case $host_cpu in
+      powerpc)
+            # see comment about AmigaOS4 .so support
+            archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+            archive_expsym_cmds=''
+        ;;
+      m68k)
+            archive_cmds='$RM $output_objdir/a2ixlibrary.data~$ECHO "#define NAME $libname" > $output_objdir/a2ixlibrary.data~$ECHO "#define LIBRARY_ID 1" >> $output_objdir/a2ixlibrary.data~$ECHO "#define VERSION $major" >> $output_objdir/a2ixlibrary.data~$ECHO "#define REVISION $revision" >> $output_objdir/a2ixlibrary.data~$AR $AR_FLAGS $lib $libobjs~$RANLIB $lib~(cd $output_objdir && a2ixlibrary -32)'
+            hardcode_libdir_flag_spec='-L$libdir'
+            hardcode_minus_L=yes
+        ;;
+      esac
+      ;;
+
+    bsdi[45]*)
+      export_dynamic_flag_spec=-rdynamic
+      ;;
+
+    cygwin* | mingw* | pw32* | cegcc*)
+      # When not using gcc, we currently assume that we are using
+      # Microsoft Visual C++ or Intel C++ Compiler.
+      # hardcode_libdir_flag_spec is actually meaningless, as there is
+      # no search path for DLLs.
+      case $cc_basename in
+      cl* | icl*)
+	# Native MSVC or ICC
+	hardcode_libdir_flag_spec=' '
+	allow_undefined_flag=unsupported
+	always_export_symbols=yes
+	file_list_spec='@'
+	# Tell ltmain to make .lib files, not .a files.
+	libext=lib
+	# Tell ltmain to make .dll files, not .so files.
+	shrext_cmds=.dll
+	# FIXME: Setting linknames here is a bad hack.
+	archive_cmds='$CC -o $output_objdir/$soname $libobjs $compiler_flags $deplibs -Wl,-DLL,-IMPLIB:"$tool_output_objdir$libname.dll.lib"~linknames='
+	archive_expsym_cmds='if   test DEF = "`$SED -n     -e '\''s/^[	 ]*//'\''     -e '\''/^\(;.*\)*$/d'\''     -e '\''s/^\(EXPORTS\|LIBRARY\)\([	 ].*\)*$/DEF/p'\''     -e q     $export_symbols`" ; then
+            cp "$export_symbols" "$output_objdir/$soname.def";
+            echo "$tool_output_objdir$soname.def" > "$output_objdir/$soname.exp";
+          else
+            $SED -e '\''s/^/-link -EXPORT:/'\'' < $export_symbols > $output_objdir/$soname.exp;
+          fi~
+          $CC -o $tool_output_objdir$soname $libobjs $compiler_flags $deplibs "@$tool_output_objdir$soname.exp" -Wl,-DLL,-IMPLIB:"$tool_output_objdir$libname.dll.lib"~
+          linknames='
+	# The linker will not automatically build a static lib if we build a DLL.
+	# _LT_TAGVAR(old_archive_from_new_cmds, )='true'
+	enable_shared_with_static_runtimes=yes
+	exclude_expsyms='_NULL_IMPORT_DESCRIPTOR|_IMPORT_DESCRIPTOR_.*'
+	export_symbols_cmds='$NM $libobjs $convenience | $global_symbol_pipe | $SED -e '\''/^[BCDGRS][ ]/s/.*[ ]\([^ ]*\)/\1,DATA/'\'' | $SED -e '\''/^[AITW][ ]/s/.*[ ]//'\'' | sort | uniq > $export_symbols'
+	# Don't use ranlib
+	old_postinstall_cmds='chmod 644 $oldlib'
+	postlink_cmds='lt_outputfile="@OUTPUT@"~
+          lt_tool_outputfile="@TOOL_OUTPUT@"~
+          case $lt_outputfile in
+            *.exe|*.EXE) ;;
+            *)
+              lt_outputfile=$lt_outputfile.exe
+              lt_tool_outputfile=$lt_tool_outputfile.exe
+              ;;
+          esac~
+          if test : != "$MANIFEST_TOOL" && test -f "$lt_outputfile.manifest"; then
+            $MANIFEST_TOOL -manifest "$lt_tool_outputfile.manifest" -outputresource:"$lt_tool_outputfile" || exit 1;
+            $RM "$lt_outputfile.manifest";
+          fi'
+	;;
+      *)
+	# Assume MSVC and ICC wrapper
+	hardcode_libdir_flag_spec=' '
+	allow_undefined_flag=unsupported
+	# Tell ltmain to make .lib files, not .a files.
+	libext=lib
+	# Tell ltmain to make .dll files, not .so files.
+	shrext_cmds=.dll
+	# FIXME: Setting linknames here is a bad hack.
+	archive_cmds='$CC -o $lib $libobjs $compiler_flags `func_echo_all "$deplibs" | $SED '\''s/ -lc$//'\''` -link -dll~linknames='
+	# The linker will automatically build a .lib file if we build a DLL.
+	old_archive_from_new_cmds='true'
+	# FIXME: Should let the user specify the lib program.
+	old_archive_cmds='lib -OUT:$oldlib$oldobjs$old_deplibs'
+	enable_shared_with_static_runtimes=yes
+	;;
+      esac
+      ;;
+
+    darwin* | rhapsody*)
+
+
+  archive_cmds_need_lc=no
+  hardcode_direct=no
+  hardcode_automatic=yes
+  hardcode_shlibpath_var=unsupported
+  if test yes = "$lt_cv_ld_force_load"; then
+    whole_archive_flag_spec='`for conv in $convenience\"\"; do test  -n \"$conv\" && new_convenience=\"$new_convenience $wl-force_load,$conv\"; done; func_echo_all \"$new_convenience\"`'
+
+  else
+    whole_archive_flag_spec=''
+  fi
+  link_all_deplibs=yes
+  allow_undefined_flag=$_lt_dar_allow_undefined
+  case $cc_basename in
+     ifort*|nagfor*) _lt_dar_can_shared=yes ;;
+     *) _lt_dar_can_shared=$GCC ;;
+  esac
+  if test yes = "$_lt_dar_can_shared"; then
+    output_verbose_link_cmd=func_echo_all
+    archive_cmds="\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring $_lt_dar_single_mod$_lt_dsymutil"
+    module_cmds="\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags$_lt_dsymutil"
+    archive_expsym_cmds="$SED 's|^|_|' < \$export_symbols > \$output_objdir/\$libname-symbols.expsym~\$CC -dynamiclib \$allow_undefined_flag -o \$lib \$libobjs \$deplibs \$compiler_flags -install_name \$rpath/\$soname \$verstring $_lt_dar_single_mod$_lt_dar_export_syms$_lt_dsymutil"
+    module_expsym_cmds="$SED -e 's|^|_|' < \$export_symbols > \$output_objdir/\$libname-symbols.expsym~\$CC \$allow_undefined_flag -o \$lib -bundle \$libobjs \$deplibs \$compiler_flags$_lt_dar_export_syms$_lt_dsymutil"
+
+  else
+  ld_shlibs=no
+  fi
+
+      ;;
+
+    dgux*)
+      archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_shlibpath_var=no
+      ;;
+
+    # FreeBSD 2.2.[012] allows us to include c++rt0.o to get C++ constructor
+    # support.  Future versions do this automatically, but an explicit c++rt0.o
+    # does not break anything, and helps significantly (at the cost of a little
+    # extra space).
+    freebsd2.2*)
+      archive_cmds='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags /usr/lib/c++rt0.o'
+      hardcode_libdir_flag_spec='-R$libdir'
+      hardcode_direct=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    # Unfortunately, older versions of FreeBSD 2 do not have this feature.
+    freebsd2.*)
+      archive_cmds='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_direct=yes
+      hardcode_minus_L=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    # FreeBSD 3 and greater uses gcc -shared to do shared libraries.
+    freebsd* | dragonfly* | midnightbsd*)
+      archive_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+      hardcode_libdir_flag_spec='-R$libdir'
+      hardcode_direct=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    hpux9*)
+      if test yes = "$GCC"; then
+	archive_cmds='$RM $output_objdir/$soname~$CC -shared $pic_flag $wl+b $wl$install_libdir -o $output_objdir/$soname $libobjs $deplibs $compiler_flags~test "x$output_objdir/$soname" = "x$lib" || mv $output_objdir/$soname $lib'
+      else
+	archive_cmds='$RM $output_objdir/$soname~$LD -b +b $install_libdir -o $output_objdir/$soname $libobjs $deplibs $linker_flags~test "x$output_objdir/$soname" = "x$lib" || mv $output_objdir/$soname $lib'
+      fi
+      hardcode_libdir_flag_spec='$wl+b $wl$libdir'
+      hardcode_libdir_separator=:
+      hardcode_direct=yes
+
+      # hardcode_minus_L: Not really in the search PATH,
+      # but as the default location of the library.
+      hardcode_minus_L=yes
+      export_dynamic_flag_spec='$wl-E'
+      ;;
+
+    hpux10*)
+      if test yes,no = "$GCC,$with_gnu_ld"; then
+	archive_cmds='$CC -shared $pic_flag $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	archive_cmds='$LD -b +h $soname +b $install_libdir -o $lib $libobjs $deplibs $linker_flags'
+      fi
+      if test no = "$with_gnu_ld"; then
+	hardcode_libdir_flag_spec='$wl+b $wl$libdir'
+	hardcode_libdir_separator=:
+	hardcode_direct=yes
+	hardcode_direct_absolute=yes
+	export_dynamic_flag_spec='$wl-E'
+	# hardcode_minus_L: Not really in the search PATH,
+	# but as the default location of the library.
+	hardcode_minus_L=yes
+      fi
+      ;;
+
+    hpux11*)
+      if test yes,no = "$GCC,$with_gnu_ld"; then
+	case $host_cpu in
+	hppa*64*)
+	  archive_cmds='$CC -shared $wl+h $wl$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	ia64*)
+	  archive_cmds='$CC -shared $pic_flag $wl+h $wl$soname $wl+nodefaultrpath -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	*)
+	  archive_cmds='$CC -shared $pic_flag $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	esac
+      else
+	case $host_cpu in
+	hppa*64*)
+	  archive_cmds='$CC -b $wl+h $wl$soname -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	ia64*)
+	  archive_cmds='$CC -b $wl+h $wl$soname $wl+nodefaultrpath -o $lib $libobjs $deplibs $compiler_flags'
+	  ;;
+	*)
+
+	  # Older versions of the 11.00 compiler do not understand -b yet
+	  # (HP92453-01 A.11.01.20 doesn't, HP92453-01 B.11.X.35175-35176.GP does)
+	  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if $CC understands -b" >&5
+printf %s "checking if $CC understands -b... " >&6; }
+if test ${lt_cv_prog_compiler__b+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_prog_compiler__b=no
+   save_LDFLAGS=$LDFLAGS
+   LDFLAGS="$LDFLAGS -b"
+   echo "$lt_simple_link_test_code" > conftest.$ac_ext
+   if (eval $ac_link 2>conftest.err) && test -s conftest$ac_exeext; then
+     # The linker can only warn and ignore the option if not recognized
+     # So say no if there are warnings
+     if test -s conftest.err; then
+       # Append any errors to the config.log.
+       cat conftest.err 1>&5
+       $ECHO "$_lt_linker_boilerplate" | $SED '/^$/d' > conftest.exp
+       $SED '/^$/d; /^ *+/d' conftest.err >conftest.er2
+       if diff conftest.exp conftest.er2 >/dev/null; then
+         lt_cv_prog_compiler__b=yes
+       fi
+     else
+       lt_cv_prog_compiler__b=yes
+     fi
+   fi
+   $RM -r conftest*
+   LDFLAGS=$save_LDFLAGS
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_compiler__b" >&5
+printf "%s\n" "$lt_cv_prog_compiler__b" >&6; }
+
+if test yes = "$lt_cv_prog_compiler__b"; then
+    archive_cmds='$CC -b $wl+h $wl$soname $wl+b $wl$install_libdir -o $lib $libobjs $deplibs $compiler_flags'
+else
+    archive_cmds='$LD -b +h $soname +b $install_libdir -o $lib $libobjs $deplibs $linker_flags'
+fi
+
+	  ;;
+	esac
+      fi
+      if test no = "$with_gnu_ld"; then
+	hardcode_libdir_flag_spec='$wl+b $wl$libdir'
+	hardcode_libdir_separator=:
+
+	case $host_cpu in
+	hppa*64*|ia64*)
+	  hardcode_direct=no
+	  hardcode_shlibpath_var=no
+	  ;;
+	*)
+	  hardcode_direct=yes
+	  hardcode_direct_absolute=yes
+	  export_dynamic_flag_spec='$wl-E'
+
+	  # hardcode_minus_L: Not really in the search PATH,
+	  # but as the default location of the library.
+	  hardcode_minus_L=yes
+	  ;;
+	esac
+      fi
+      ;;
+
+    irix5* | irix6* | nonstopux*)
+      if test yes = "$GCC"; then
+	archive_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+	# Try to use the -exported_symbol ld option, if it does not
+	# work, assume that -exports_file does not work either and
+	# implicitly export all symbols.
+	# This should be the same for all languages, so no per-tag cache variable.
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the $host_os linker accepts -exported_symbol" >&5
+printf %s "checking whether the $host_os linker accepts -exported_symbol... " >&6; }
+if test ${lt_cv_irix_exported_symbol+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) save_LDFLAGS=$LDFLAGS
+	   LDFLAGS="$LDFLAGS -shared $wl-exported_symbol ${wl}foo $wl-update_registry $wl/dev/null"
+	   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+int foo (void) { return 0; }
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  lt_cv_irix_exported_symbol=yes
+else case e in #(
+  e) lt_cv_irix_exported_symbol=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+           LDFLAGS=$save_LDFLAGS ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_irix_exported_symbol" >&5
+printf "%s\n" "$lt_cv_irix_exported_symbol" >&6; }
+	if test yes = "$lt_cv_irix_exported_symbol"; then
+          archive_expsym_cmds='$CC -shared $pic_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations $wl-exports_file $wl$export_symbols -o $lib'
+	fi
+      else
+	archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+	archive_expsym_cmds='$CC -shared $libobjs $deplibs $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -exports_file $export_symbols -o $lib'
+      fi
+      archive_cmds_need_lc='no'
+      hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+      hardcode_libdir_separator=:
+      inherit_rpath=yes
+      link_all_deplibs=yes
+      ;;
+
+    linux*)
+      case $cc_basename in
+      tcc*)
+	# Fabrice Bellard et al's Tiny C Compiler
+	ld_shlibs=yes
+	archive_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+	;;
+      esac
+      ;;
+
+    netbsd*)
+      if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+	archive_cmds='$LD -Bshareable -o $lib $libobjs $deplibs $linker_flags'  # a.out
+      else
+	archive_cmds='$LD -shared -o $lib $libobjs $deplibs $linker_flags'      # ELF
+      fi
+      hardcode_libdir_flag_spec='-R$libdir'
+      hardcode_direct=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    newsos6)
+      archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_direct=yes
+      hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+      hardcode_libdir_separator=:
+      hardcode_shlibpath_var=no
+      ;;
+
+    *nto* | *qnx*)
+      ;;
+
+    openbsd* | bitrig*)
+      if test -f /usr/libexec/ld.so; then
+	hardcode_direct=yes
+	hardcode_shlibpath_var=no
+	hardcode_direct_absolute=yes
+	if test -z "`echo __ELF__ | $CC -E - | $GREP __ELF__`"; then
+	  archive_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+	  archive_expsym_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags $wl-retain-symbols-file,$export_symbols'
+	  hardcode_libdir_flag_spec='$wl-rpath,$libdir'
+	  export_dynamic_flag_spec='$wl-E'
+	else
+	  archive_cmds='$CC -shared $pic_flag -o $lib $libobjs $deplibs $compiler_flags'
+	  hardcode_libdir_flag_spec='$wl-rpath,$libdir'
+	fi
+      else
+	ld_shlibs=no
+      fi
+      ;;
+
+    os2*)
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_minus_L=yes
+      allow_undefined_flag=unsupported
+      shrext_cmds=.dll
+      archive_cmds='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	emxexp $libobjs | $SED /"_DLL_InitTerm"/d >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      archive_expsym_cmds='$ECHO "LIBRARY ${soname%$shared_ext} INITINSTANCE TERMINSTANCE" > $output_objdir/$libname.def~
+	$ECHO "DESCRIPTION \"$libname\"" >> $output_objdir/$libname.def~
+	$ECHO "DATA MULTIPLE NONSHARED" >> $output_objdir/$libname.def~
+	$ECHO EXPORTS >> $output_objdir/$libname.def~
+	prefix_cmds="$SED"~
+	if test EXPORTS = "`$SED 1q $export_symbols`"; then
+	  prefix_cmds="$prefix_cmds -e 1d";
+	fi~
+	prefix_cmds="$prefix_cmds -e \"s/^\(.*\)$/_\1/g\""~
+	cat $export_symbols | $prefix_cmds >> $output_objdir/$libname.def~
+	$CC -Zdll -Zcrtdll -o $output_objdir/$soname $libobjs $deplibs $compiler_flags $output_objdir/$libname.def~
+	emximp -o $lib $output_objdir/$libname.def'
+      old_archive_From_new_cmds='emximp -o $output_objdir/${libname}_dll.a $output_objdir/$libname.def'
+      enable_shared_with_static_runtimes=yes
+      file_list_spec='@'
+      ;;
+
+    osf3*)
+      if test yes = "$GCC"; then
+	allow_undefined_flag=' $wl-expect_unresolved $wl\*'
+	archive_cmds='$CC -shared$allow_undefined_flag $libobjs $deplibs $compiler_flags $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+      else
+	allow_undefined_flag=' -expect_unresolved \*'
+	archive_cmds='$CC -shared$allow_undefined_flag $libobjs $deplibs $compiler_flags -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+      fi
+      archive_cmds_need_lc='no'
+      hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+      hardcode_libdir_separator=:
+      ;;
+
+    osf4* | osf5*)	# as osf3* with the addition of -msym flag
+      if test yes = "$GCC"; then
+	allow_undefined_flag=' $wl-expect_unresolved $wl\*'
+	archive_cmds='$CC -shared$allow_undefined_flag $pic_flag $libobjs $deplibs $compiler_flags $wl-msym $wl-soname $wl$soname `test -n "$verstring" && func_echo_all "$wl-set_version $wl$verstring"` $wl-update_registry $wl$output_objdir/so_locations -o $lib'
+	hardcode_libdir_flag_spec='$wl-rpath $wl$libdir'
+      else
+	allow_undefined_flag=' -expect_unresolved \*'
+	archive_cmds='$CC -shared$allow_undefined_flag $libobjs $deplibs $compiler_flags -msym -soname $soname `test -n "$verstring" && func_echo_all "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib'
+	archive_expsym_cmds='for i in `cat $export_symbols`; do printf "%s %s\\n" -exported_symbol "\$i" >> $lib.exp; done; printf "%s\\n" "-hidden">> $lib.exp~
+          $CC -shared$allow_undefined_flag $wl-input $wl$lib.exp $compiler_flags $libobjs $deplibs -soname $soname `test -n "$verstring" && $ECHO "-set_version $verstring"` -update_registry $output_objdir/so_locations -o $lib~$RM $lib.exp'
+
+	# Both c and cxx compiler support -rpath directly
+	hardcode_libdir_flag_spec='-rpath $libdir'
+      fi
+      archive_cmds_need_lc='no'
+      hardcode_libdir_separator=:
+      ;;
+
+    solaris*)
+      no_undefined_flag=' -z defs'
+      if test yes = "$GCC"; then
+	wlarc='$wl'
+	archive_cmds='$CC -shared $pic_flag $wl-z ${wl}text $wl-h $wl$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+          $CC -shared $pic_flag $wl-z ${wl}text $wl-M $wl$lib.exp $wl-h $wl$soname -o $lib $libobjs $deplibs $compiler_flags~$RM $lib.exp'
+      else
+	case `$CC -V 2>&1` in
+	*"Compilers 5.0"*)
+	  wlarc=''
+	  archive_cmds='$LD -G$allow_undefined_flag -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	  archive_expsym_cmds='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+            $LD -G$allow_undefined_flag -M $lib.exp -h $soname -o $lib $libobjs $deplibs $linker_flags~$RM $lib.exp'
+	  ;;
+	*)
+	  wlarc='$wl'
+	  archive_cmds='$CC -G$allow_undefined_flag -h $soname -o $lib $libobjs $deplibs $compiler_flags'
+	  archive_expsym_cmds='echo "{ global:" > $lib.exp~cat $export_symbols | $SED -e "s/\(.*\)/\1;/" >> $lib.exp~echo "local: *; };" >> $lib.exp~
+            $CC -G$allow_undefined_flag -M $lib.exp -h $soname -o $lib $libobjs $deplibs $compiler_flags~$RM $lib.exp'
+	  ;;
+	esac
+      fi
+      hardcode_libdir_flag_spec='-R$libdir'
+      hardcode_shlibpath_var=no
+      case $host_os in
+      solaris2.[0-5] | solaris2.[0-5].*) ;;
+      *)
+	# The compiler driver will combine and reorder linker options,
+	# but understands '-z linker_flag'.  GCC discards it without '$wl',
+	# but is careful enough not to reorder.
+	# Supported since Solaris 2.6 (maybe 2.5.1?)
+	if test yes = "$GCC"; then
+	  whole_archive_flag_spec='$wl-z ${wl}allextract$convenience $wl-z ${wl}defaultextract'
+	else
+	  whole_archive_flag_spec='-z allextract$convenience -z defaultextract'
+	fi
+	;;
+      esac
+      link_all_deplibs=yes
+      ;;
+
+    sunos4*)
+      if test sequent = "$host_vendor"; then
+	# Use $CC to link under sequent, because it throws in some extra .o
+	# files that make .init and .fini sections work.
+	archive_cmds='$CC -G $wl-h $soname -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	archive_cmds='$LD -assert pure-text -Bstatic -o $lib $libobjs $deplibs $linker_flags'
+      fi
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_direct=yes
+      hardcode_minus_L=yes
+      hardcode_shlibpath_var=no
+      ;;
+
+    sysv4)
+      case $host_vendor in
+	sni)
+	  archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	  hardcode_direct=yes # is this really true???
+	;;
+	siemens)
+	  ## LD is ld it makes a PLAMLIB
+	  ## CC just makes a GrossModule.
+	  archive_cmds='$LD -G -o $lib $libobjs $deplibs $linker_flags'
+	  reload_cmds='$CC -r -o $output$reload_objs'
+	  hardcode_direct=no
+        ;;
+	motorola)
+	  archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	  hardcode_direct=no #Motorola manual says yes, but my tests say they lie
+	;;
+      esac
+      runpath_var='LD_RUN_PATH'
+      hardcode_shlibpath_var=no
+      ;;
+
+    sysv4.3*)
+      archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_shlibpath_var=no
+      export_dynamic_flag_spec='-Bexport'
+      ;;
+
+    sysv4*MP*)
+      if test -d /usr/nec; then
+	archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+	hardcode_shlibpath_var=no
+	runpath_var=LD_RUN_PATH
+	hardcode_runpath_var=yes
+	ld_shlibs=yes
+      fi
+      ;;
+
+    sysv4*uw2* | sysv5OpenUNIX* | sysv5UnixWare7.[01].[10]* | unixware7* | sco3.2v5.0.[024]*)
+      no_undefined_flag='$wl-z,text'
+      archive_cmds_need_lc=no
+      hardcode_shlibpath_var=no
+      runpath_var='LD_RUN_PATH'
+
+      if test yes = "$GCC"; then
+	archive_cmds='$CC -shared $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='$CC -shared $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	archive_cmds='$CC -G $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='$CC -G $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      fi
+      ;;
+
+    sysv5* | sco3.2v5* | sco5v6*)
+      # Note: We CANNOT use -z defs as we might desire, because we do not
+      # link with -lc, and that would cause any symbols used from libc to
+      # always be unresolved, which means just about no library would
+      # ever link correctly.  If we're not using GNU ld we use -z text
+      # though, which does catch some bad symbols but isn't as heavy-handed
+      # as -z defs.
+      no_undefined_flag='$wl-z,text'
+      allow_undefined_flag='$wl-z,nodefs'
+      archive_cmds_need_lc=no
+      hardcode_shlibpath_var=no
+      hardcode_libdir_flag_spec='$wl-R,$libdir'
+      hardcode_libdir_separator=':'
+      link_all_deplibs=yes
+      export_dynamic_flag_spec='$wl-Bexport'
+      runpath_var='LD_RUN_PATH'
+
+      if test yes = "$GCC"; then
+	archive_cmds='$CC -shared $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='$CC -shared $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      else
+	archive_cmds='$CC -G $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+	archive_expsym_cmds='$CC -G $wl-Bexport:$export_symbols $wl-h,$soname -o $lib $libobjs $deplibs $compiler_flags'
+      fi
+      ;;
+
+    uts4*)
+      archive_cmds='$LD -G -h $soname -o $lib $libobjs $deplibs $linker_flags'
+      hardcode_libdir_flag_spec='-L$libdir'
+      hardcode_shlibpath_var=no
+      ;;
+
+    *)
+      ld_shlibs=no
+      ;;
+    esac
+
+    if test sni = "$host_vendor"; then
+      case $host in
+      sysv4 | sysv4.2uw2* | sysv4.3* | sysv5*)
+	export_dynamic_flag_spec='$wl-Blargedynsym'
+	;;
+      esac
+    fi
+  fi
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ld_shlibs" >&5
+printf "%s\n" "$ld_shlibs" >&6; }
+test no = "$ld_shlibs" && can_build_shared=no
+
+with_gnu_ld=$with_gnu_ld
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+#
+# Do we need to explicitly link libc?
+#
+case "x$archive_cmds_need_lc" in
+x|xyes)
+  # Assume -lc should be added
+  archive_cmds_need_lc=yes
+
+  if test yes,yes = "$GCC,$enable_shared"; then
+    case $archive_cmds in
+    *'~'*)
+      # FIXME: we may have to deal with multi-command sequences.
+      ;;
+    '$CC '*)
+      # Test whether the compiler implicitly links with -lc since on some
+      # systems, -lgcc has to come before -lc. If gcc already passes -lc
+      # to ld, don't add -lc before -lgcc.
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether -lc should be explicitly linked in" >&5
+printf %s "checking whether -lc should be explicitly linked in... " >&6; }
+if test ${lt_cv_archive_cmds_need_lc+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) $RM conftest*
+	echo "$lt_simple_compile_test_code" > conftest.$ac_ext
+
+	if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_compile\""; } >&5
+  (eval $ac_compile) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } 2>conftest.err; then
+	  soname=conftest
+	  lib=conftest
+	  libobjs=conftest.$ac_objext
+	  deplibs=
+	  wl=$lt_prog_compiler_wl
+	  pic_flag=$lt_prog_compiler_pic
+	  compiler_flags=-v
+	  linker_flags=-v
+	  verstring=
+	  output_objdir=.
+	  libname=conftest
+	  lt_save_allow_undefined_flag=$allow_undefined_flag
+	  allow_undefined_flag=
+	  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$archive_cmds 2\>\&1 \| $GREP \" -lc \" \>/dev/null 2\>\&1\""; } >&5
+  (eval $archive_cmds 2\>\&1 \| $GREP \" -lc \" \>/dev/null 2\>\&1) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+	  then
+	    lt_cv_archive_cmds_need_lc=no
+	  else
+	    lt_cv_archive_cmds_need_lc=yes
+	  fi
+	  allow_undefined_flag=$lt_save_allow_undefined_flag
+	else
+	  cat conftest.err 1>&5
+	fi
+	$RM conftest*
+	 ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_archive_cmds_need_lc" >&5
+printf "%s\n" "$lt_cv_archive_cmds_need_lc" >&6; }
+      archive_cmds_need_lc=$lt_cv_archive_cmds_need_lc
+      ;;
+    esac
+  fi
+  ;;
+esac
+
+
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+
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking dynamic linker characteristics" >&5
+printf %s "checking dynamic linker characteristics... " >&6; }
+
+if test yes = "$GCC"; then
+  case $host_os in
+    darwin*) lt_awk_arg='/^libraries:/,/LR/' ;;
+    *) lt_awk_arg='/^libraries:/' ;;
+  esac
+  case $host_os in
+    mingw* | cegcc*) lt_sed_strip_eq='s|=\([A-Za-z]:\)|\1|g' ;;
+    *) lt_sed_strip_eq='s|=/|/|g' ;;
+  esac
+  lt_search_path_spec=`$CC -print-search-dirs | awk $lt_awk_arg | $SED -e "s/^libraries://" -e $lt_sed_strip_eq`
+  case $lt_search_path_spec in
+  *\;*)
+    # if the path contains ";" then we assume it to be the separator
+    # otherwise default to the standard path separator (i.e. ":") - it is
+    # assumed that no part of a normal pathname contains ";" but that should
+    # okay in the real world where ";" in dirpaths is itself problematic.
+    lt_search_path_spec=`$ECHO "$lt_search_path_spec" | $SED 's/;/ /g'`
+    ;;
+  *)
+    lt_search_path_spec=`$ECHO "$lt_search_path_spec" | $SED "s/$PATH_SEPARATOR/ /g"`
+    ;;
+  esac
+  # Ok, now we have the path, separated by spaces, we can step through it
+  # and add multilib dir if necessary...
+  lt_tmp_lt_search_path_spec=
+  lt_multi_os_dir=/`$CC $CPPFLAGS $CFLAGS $LDFLAGS -print-multi-os-directory 2>/dev/null`
+  # ...but if some path component already ends with the multilib dir we assume
+  # that all is fine and trust -print-search-dirs as is (GCC 4.2? or newer).
+  case "$lt_multi_os_dir; $lt_search_path_spec " in
+  "/; "* | "/.; "* | "/./; "* | *"$lt_multi_os_dir "* | *"$lt_multi_os_dir/ "*)
+    lt_multi_os_dir=
+    ;;
+  esac
+  for lt_sys_path in $lt_search_path_spec; do
+    if test -d "$lt_sys_path$lt_multi_os_dir"; then
+      lt_tmp_lt_search_path_spec="$lt_tmp_lt_search_path_spec $lt_sys_path$lt_multi_os_dir"
+    elif test -n "$lt_multi_os_dir"; then
+      test -d "$lt_sys_path" && \
+	lt_tmp_lt_search_path_spec="$lt_tmp_lt_search_path_spec $lt_sys_path"
+    fi
+  done
+  lt_search_path_spec=`$ECHO "$lt_tmp_lt_search_path_spec" | awk '
+BEGIN {RS = " "; FS = "/|\n";} {
+  lt_foo = "";
+  lt_count = 0;
+  for (lt_i = NF; lt_i > 0; lt_i--) {
+    if ($lt_i != "" && $lt_i != ".") {
+      if ($lt_i == "..") {
+        lt_count++;
+      } else {
+        if (lt_count == 0) {
+          lt_foo = "/" $lt_i lt_foo;
+        } else {
+          lt_count--;
+        }
+      }
+    }
+  }
+  if (lt_foo != "") { lt_freq[lt_foo]++; }
+  if (lt_freq[lt_foo] == 1) { print lt_foo; }
+}'`
+  # AWK program above erroneously prepends '/' to C:/dos/paths
+  # for these hosts.
+  case $host_os in
+    mingw* | cegcc*) lt_search_path_spec=`$ECHO "$lt_search_path_spec" |\
+      $SED 's|/\([A-Za-z]:\)|\1|g'` ;;
+  esac
+  sys_lib_search_path_spec=`$ECHO "$lt_search_path_spec" | $lt_NL2SP`
+else
+  sys_lib_search_path_spec="/lib /usr/lib /usr/local/lib"
+fi
+library_names_spec=
+libname_spec='lib$name'
+soname_spec=
+shrext_cmds=.so
+postinstall_cmds=
+postuninstall_cmds=
+finish_cmds=
+finish_eval=
+shlibpath_var=
+shlibpath_overrides_runpath=unknown
+version_type=none
+dynamic_linker="$host_os ld.so"
+sys_lib_dlsearch_path_spec="/lib /usr/lib"
+need_lib_prefix=unknown
+hardcode_into_libs=no
+
+# when you set need_version to no, make sure it does not cause -set_version
+# flags to be left without arguments
+need_version=unknown
+
+
+
+case $host_os in
+aix3*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname.a'
+  shlibpath_var=LIBPATH
+
+  # AIX 3 has no versioning support, so we append a major version to the name.
+  soname_spec='$libname$release$shared_ext$major'
+  ;;
+
+aix[4-9]*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  hardcode_into_libs=yes
+  if test ia64 = "$host_cpu"; then
+    # AIX 5 supports IA64
+    library_names_spec='$libname$release$shared_ext$major $libname$release$shared_ext$versuffix $libname$shared_ext'
+    shlibpath_var=LD_LIBRARY_PATH
+  else
+    # With GCC up to 2.95.x, collect2 would create an import file
+    # for dependence libraries.  The import file would start with
+    # the line '#! .'.  This would cause the generated library to
+    # depend on '.', always an invalid library.  This was fixed in
+    # development snapshots of GCC prior to 3.0.
+    case $host_os in
+      aix4 | aix4.[01] | aix4.[01].*)
+      if { echo '#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 97)'
+	   echo ' yes '
+	   echo '#endif'; } | $CC -E - | $GREP yes > /dev/null; then
+	:
+      else
+	can_build_shared=no
+      fi
+      ;;
+    esac
+    # Using Import Files as archive members, it is possible to support
+    # filename-based versioning of shared library archives on AIX. While
+    # this would work for both with and without runtime linking, it will
+    # prevent static linking of such archives. So we do filename-based
+    # shared library versioning with .so extension only, which is used
+    # when both runtime linking and shared linking is enabled.
+    # Unfortunately, runtime linking may impact performance, so we do
+    # not want this to be the default eventually. Also, we use the
+    # versioned .so libs for executables only if there is the -brtl
+    # linker flag in LDFLAGS as well, or --with-aix-soname=svr4 only.
+    # To allow for filename-based versioning support, we need to create
+    # libNAME.so.V as an archive file, containing:
+    # *) an Import File, referring to the versioned filename of the
+    #    archive as well as the shared archive member, telling the
+    #    bitwidth (32 or 64) of that shared object, and providing the
+    #    list of exported symbols of that shared object, eventually
+    #    decorated with the 'weak' keyword
+    # *) the shared object with the F_LOADONLY flag set, to really avoid
+    #    it being seen by the linker.
+    # At run time we better use the real file rather than another symlink,
+    # but for link time we create the symlink libNAME.so -> libNAME.so.V
+
+    case $with_aix_soname,$aix_use_runtimelinking in
+    # AIX (on Power*) has no versioning support, so currently we cannot hardcode correct
+    # soname into executable. Probably we can add versioning support to
+    # collect2, so additional links can be useful in future.
+    aix,yes) # traditional libtool
+      dynamic_linker='AIX unversionable lib.so'
+      # If using run time linking (on AIX 4.2 or later) use lib<name>.so
+      # instead of lib<name>.a to let people know that these are not
+      # typical AIX shared libraries.
+      library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+      ;;
+    aix,no) # traditional AIX only
+      dynamic_linker='AIX lib.a(lib.so.V)'
+      # We preserve .a as extension for shared libraries through AIX4.2
+      # and later when we are not doing run time linking.
+      library_names_spec='$libname$release.a $libname.a'
+      soname_spec='$libname$release$shared_ext$major'
+      ;;
+    svr4,*) # full svr4 only
+      dynamic_linker="AIX lib.so.V($shared_archive_member_spec.o)"
+      library_names_spec='$libname$release$shared_ext$major $libname$shared_ext'
+      # We do not specify a path in Import Files, so LIBPATH fires.
+      shlibpath_overrides_runpath=yes
+      ;;
+    *,yes) # both, prefer svr4
+      dynamic_linker="AIX lib.so.V($shared_archive_member_spec.o), lib.a(lib.so.V)"
+      library_names_spec='$libname$release$shared_ext$major $libname$shared_ext'
+      # unpreferred sharedlib libNAME.a needs extra handling
+      postinstall_cmds='test -n "$linkname" || linkname="$realname"~func_stripname "" ".so" "$linkname"~$install_shared_prog "$dir/$func_stripname_result.$libext" "$destdir/$func_stripname_result.$libext"~test -z "$tstripme" || test -z "$striplib" || $striplib "$destdir/$func_stripname_result.$libext"'
+      postuninstall_cmds='for n in $library_names $old_library; do :; done~func_stripname "" ".so" "$n"~test "$func_stripname_result" = "$n" || func_append rmfiles " $odir/$func_stripname_result.$libext"'
+      # We do not specify a path in Import Files, so LIBPATH fires.
+      shlibpath_overrides_runpath=yes
+      ;;
+    *,no) # both, prefer aix
+      dynamic_linker="AIX lib.a(lib.so.V), lib.so.V($shared_archive_member_spec.o)"
+      library_names_spec='$libname$release.a $libname.a'
+      soname_spec='$libname$release$shared_ext$major'
+      # unpreferred sharedlib libNAME.so.V and symlink libNAME.so need extra handling
+      postinstall_cmds='test -z "$dlname" || $install_shared_prog $dir/$dlname $destdir/$dlname~test -z "$tstripme" || test -z "$striplib" || $striplib $destdir/$dlname~test -n "$linkname" || linkname=$realname~func_stripname "" ".a" "$linkname"~(cd "$destdir" && $LN_S -f $dlname $func_stripname_result.so)'
+      postuninstall_cmds='test -z "$dlname" || func_append rmfiles " $odir/$dlname"~for n in $old_library $library_names; do :; done~func_stripname "" ".a" "$n"~func_append rmfiles " $odir/$func_stripname_result.so"'
+      ;;
+    esac
+    shlibpath_var=LIBPATH
+  fi
+  ;;
+
+amigaos*)
+  case $host_cpu in
+  powerpc)
+    # Since July 2007 AmigaOS4 officially supports .so libraries.
+    # When compiling the executable, add -use-dynld -Lsobjs: to the compileline.
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    ;;
+  m68k)
+    library_names_spec='$libname.ixlibrary $libname.a'
+    # Create ${libname}_ixlibrary.a entries in /sys/libs.
+    finish_eval='for lib in `ls $libdir/*.ixlibrary 2>/dev/null`; do libname=`func_echo_all "$lib" | $SED '\''s%^.*/\([^/]*\)\.ixlibrary$%\1%'\''`; $RM /sys/libs/${libname}_ixlibrary.a; $show "cd /sys/libs && $LN_S $lib ${libname}_ixlibrary.a"; cd /sys/libs && $LN_S $lib ${libname}_ixlibrary.a || exit 1; done'
+    ;;
+  esac
+  ;;
+
+beos*)
+  library_names_spec='$libname$shared_ext'
+  dynamic_linker="$host_os ld.so"
+  shlibpath_var=LIBRARY_PATH
+  ;;
+
+bsdi[45]*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  finish_cmds='PATH="\$PATH:/sbin" ldconfig $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  sys_lib_search_path_spec="/shlib /usr/lib /usr/X11/lib /usr/contrib/lib /lib /usr/local/lib"
+  sys_lib_dlsearch_path_spec="/shlib /usr/lib /usr/local/lib"
+  # the default ld.so.conf also contains /usr/contrib/lib and
+  # /usr/X11R6/lib (/usr/X11 is a link to /usr/X11R6), but let us allow
+  # libtool to hard-code these into programs
+  ;;
+
+cygwin* | mingw* | pw32* | cegcc*)
+  version_type=windows
+  shrext_cmds=.dll
+  need_version=no
+  need_lib_prefix=no
+
+  case $GCC,$cc_basename in
+  yes,*)
+    # gcc
+    library_names_spec='$libname.dll.a'
+    # DLL is installed to $(libdir)/../bin by postinstall_cmds
+    postinstall_cmds='base_file=`basename \$file`~
+      dlpath=`$SHELL 2>&1 -c '\''. $dir/'\''\$base_file'\''i; echo \$dlname'\''`~
+      dldir=$destdir/`dirname \$dlpath`~
+      test -d \$dldir || mkdir -p \$dldir~
+      $install_prog $dir/$dlname \$dldir/$dlname~
+      chmod a+x \$dldir/$dlname~
+      if test -n '\''$stripme'\'' && test -n '\''$striplib'\''; then
+        eval '\''$striplib \$dldir/$dlname'\'' || exit \$?;
+      fi'
+    postuninstall_cmds='dldll=`$SHELL 2>&1 -c '\''. $file; echo \$dlname'\''`~
+      dlpath=$dir/\$dldll~
+       $RM \$dlpath'
+    shlibpath_overrides_runpath=yes
+
+    case $host_os in
+    cygwin*)
+      # Cygwin DLLs use 'cyg' prefix rather than 'lib'
+      soname_spec='`echo $libname | $SED -e 's/^lib/cyg/'``echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext'
+
+      sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/lib/w32api"
+      ;;
+    mingw* | cegcc*)
+      # MinGW DLLs use traditional 'lib' prefix
+      soname_spec='$libname`echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext'
+      ;;
+    pw32*)
+      # pw32 DLLs use 'pw' prefix rather than 'lib'
+      library_names_spec='`echo $libname | $SED -e 's/^lib/pw/'``echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext'
+      ;;
+    esac
+    dynamic_linker='Win32 ld.exe'
+    ;;
+
+  *,cl* | *,icl*)
+    # Native MSVC or ICC
+    libname_spec='$name'
+    soname_spec='$libname`echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext'
+    library_names_spec='$libname.dll.lib'
+
+    case $build_os in
+    mingw*)
+      sys_lib_search_path_spec=
+      lt_save_ifs=$IFS
+      IFS=';'
+      for lt_path in $LIB
+      do
+        IFS=$lt_save_ifs
+        # Let DOS variable expansion print the short 8.3 style file name.
+        lt_path=`cd "$lt_path" 2>/dev/null && cmd //C "for %i in (".") do @echo %~si"`
+        sys_lib_search_path_spec="$sys_lib_search_path_spec $lt_path"
+      done
+      IFS=$lt_save_ifs
+      # Convert to MSYS style.
+      sys_lib_search_path_spec=`$ECHO "$sys_lib_search_path_spec" | $SED -e 's|\\\\|/|g' -e 's| \\([a-zA-Z]\\):| /\\1|g' -e 's|^ ||'`
+      ;;
+    cygwin*)
+      # Convert to unix form, then to dos form, then back to unix form
+      # but this time dos style (no spaces!) so that the unix form looks
+      # like /cygdrive/c/PROGRA~1:/cygdr...
+      sys_lib_search_path_spec=`cygpath --path --unix "$LIB"`
+      sys_lib_search_path_spec=`cygpath --path --dos "$sys_lib_search_path_spec" 2>/dev/null`
+      sys_lib_search_path_spec=`cygpath --path --unix "$sys_lib_search_path_spec" | $SED -e "s/$PATH_SEPARATOR/ /g"`
+      ;;
+    *)
+      sys_lib_search_path_spec=$LIB
+      if $ECHO "$sys_lib_search_path_spec" | $GREP ';[c-zC-Z]:/' >/dev/null; then
+        # It is most probably a Windows format PATH.
+        sys_lib_search_path_spec=`$ECHO "$sys_lib_search_path_spec" | $SED -e 's/;/ /g'`
+      else
+        sys_lib_search_path_spec=`$ECHO "$sys_lib_search_path_spec" | $SED -e "s/$PATH_SEPARATOR/ /g"`
+      fi
+      # FIXME: find the short name or the path components, as spaces are
+      # common. (e.g. "Program Files" -> "PROGRA~1")
+      ;;
+    esac
+
+    # DLL is installed to $(libdir)/../bin by postinstall_cmds
+    postinstall_cmds='base_file=`basename \$file`~
+      dlpath=`$SHELL 2>&1 -c '\''. $dir/'\''\$base_file'\''i; echo \$dlname'\''`~
+      dldir=$destdir/`dirname \$dlpath`~
+      test -d \$dldir || mkdir -p \$dldir~
+      $install_prog $dir/$dlname \$dldir/$dlname'
+    postuninstall_cmds='dldll=`$SHELL 2>&1 -c '\''. $file; echo \$dlname'\''`~
+      dlpath=$dir/\$dldll~
+       $RM \$dlpath'
+    shlibpath_overrides_runpath=yes
+    dynamic_linker='Win32 link.exe'
+    ;;
+
+  *)
+    # Assume MSVC and ICC wrapper
+    library_names_spec='$libname`echo $release | $SED -e 's/[.]/-/g'`$versuffix$shared_ext $libname.lib'
+    dynamic_linker='Win32 ld.exe'
+    ;;
+  esac
+  # FIXME: first we should search . and the directory the executable is in
+  shlibpath_var=PATH
+  ;;
+
+darwin* | rhapsody*)
+  dynamic_linker="$host_os dyld"
+  version_type=darwin
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$major$shared_ext $libname$shared_ext'
+  soname_spec='$libname$release$major$shared_ext'
+  shlibpath_overrides_runpath=yes
+  shlibpath_var=DYLD_LIBRARY_PATH
+  shrext_cmds='`test .$module = .yes && echo .so || echo .dylib`'
+
+  sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/local/lib"
+  sys_lib_dlsearch_path_spec='/usr/local/lib /lib /usr/lib'
+  ;;
+
+dgux*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  ;;
+
+freebsd* | dragonfly* | midnightbsd*)
+  # DragonFly does not have aout.  When/if they implement a new
+  # versioning mechanism, adjust this.
+  if test -x /usr/bin/objformat; then
+    objformat=`/usr/bin/objformat`
+  else
+    case $host_os in
+    freebsd[23].*) objformat=aout ;;
+    *) objformat=elf ;;
+    esac
+  fi
+  version_type=freebsd-$objformat
+  case $version_type in
+    freebsd-elf*)
+      library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+      soname_spec='$libname$release$shared_ext$major'
+      need_version=no
+      need_lib_prefix=no
+      ;;
+    freebsd-*)
+      library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+      need_version=yes
+      ;;
+  esac
+  shlibpath_var=LD_LIBRARY_PATH
+  case $host_os in
+  freebsd2.*)
+    shlibpath_overrides_runpath=yes
+    ;;
+  freebsd3.[01]* | freebsdelf3.[01]*)
+    shlibpath_overrides_runpath=yes
+    hardcode_into_libs=yes
+    ;;
+  freebsd3.[2-9]* | freebsdelf3.[2-9]* | \
+  freebsd4.[0-5] | freebsdelf4.[0-5] | freebsd4.1.1 | freebsdelf4.1.1)
+    shlibpath_overrides_runpath=no
+    hardcode_into_libs=yes
+    ;;
+  *) # from 4.6 on, and DragonFly
+    shlibpath_overrides_runpath=yes
+    hardcode_into_libs=yes
+    ;;
+  esac
+  ;;
+
+haiku*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  dynamic_linker="$host_os runtime_loader"
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  sys_lib_dlsearch_path_spec='/boot/home/config/lib /boot/common/lib /boot/system/lib'
+  hardcode_into_libs=yes
+  ;;
+
+hpux9* | hpux10* | hpux11*)
+  # Give a soname corresponding to the major version so that dld.sl refuses to
+  # link against other versions.
+  version_type=sunos
+  need_lib_prefix=no
+  need_version=no
+  case $host_cpu in
+  ia64*)
+    shrext_cmds='.so'
+    hardcode_into_libs=yes
+    dynamic_linker="$host_os dld.so"
+    shlibpath_var=LD_LIBRARY_PATH
+    shlibpath_overrides_runpath=yes # Unless +noenvvar is specified.
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    if test 32 = "$HPUX_IA64_MODE"; then
+      sys_lib_search_path_spec="/usr/lib/hpux32 /usr/local/lib/hpux32 /usr/local/lib"
+      sys_lib_dlsearch_path_spec=/usr/lib/hpux32
+    else
+      sys_lib_search_path_spec="/usr/lib/hpux64 /usr/local/lib/hpux64"
+      sys_lib_dlsearch_path_spec=/usr/lib/hpux64
+    fi
+    ;;
+  hppa*64*)
+    shrext_cmds='.sl'
+    hardcode_into_libs=yes
+    dynamic_linker="$host_os dld.sl"
+    shlibpath_var=LD_LIBRARY_PATH # How should we handle SHLIB_PATH
+    shlibpath_overrides_runpath=yes # Unless +noenvvar is specified.
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    sys_lib_search_path_spec="/usr/lib/pa20_64 /usr/ccs/lib/pa20_64"
+    sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
+    ;;
+  *)
+    shrext_cmds='.sl'
+    dynamic_linker="$host_os dld.sl"
+    shlibpath_var=SHLIB_PATH
+    shlibpath_overrides_runpath=no # +s is required to enable SHLIB_PATH
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    ;;
+  esac
+  # HP-UX runs *really* slowly unless shared libraries are mode 555, ...
+  postinstall_cmds='chmod 555 $lib'
+  # or fails outright, so override atomically:
+  install_override_mode=555
+  ;;
+
+interix[3-9]*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  dynamic_linker='Interix 3.x ld.so.1 (PE, like ELF)'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  ;;
+
+irix5* | irix6* | nonstopux*)
+  case $host_os in
+    nonstopux*) version_type=nonstopux ;;
+    *)
+	if test yes = "$lt_cv_prog_gnu_ld"; then
+		version_type=linux # correct to gnu/linux during the next big refactor
+	else
+		version_type=irix
+	fi ;;
+  esac
+  need_lib_prefix=no
+  need_version=no
+  soname_spec='$libname$release$shared_ext$major'
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$release$shared_ext $libname$shared_ext'
+  case $host_os in
+  irix5* | nonstopux*)
+    libsuff= shlibsuff=
+    ;;
+  *)
+    case $LD in # libtool.m4 will add one of these switches to LD
+    *-32|*"-32 "|*-melf32bsmip|*"-melf32bsmip ")
+      libsuff= shlibsuff= libmagic=32-bit;;
+    *-n32|*"-n32 "|*-melf32bmipn32|*"-melf32bmipn32 ")
+      libsuff=32 shlibsuff=N32 libmagic=N32;;
+    *-64|*"-64 "|*-melf64bmip|*"-melf64bmip ")
+      libsuff=64 shlibsuff=64 libmagic=64-bit;;
+    *) libsuff= shlibsuff= libmagic=never-match;;
+    esac
+    ;;
+  esac
+  shlibpath_var=LD_LIBRARY${shlibsuff}_PATH
+  shlibpath_overrides_runpath=no
+  sys_lib_search_path_spec="/usr/lib$libsuff /lib$libsuff /usr/local/lib$libsuff"
+  sys_lib_dlsearch_path_spec="/usr/lib$libsuff /lib$libsuff"
+  hardcode_into_libs=yes
+  ;;
+
+# No shared lib support for Linux oldld, aout, or coff.
+linux*oldld* | linux*aout* | linux*coff*)
+  dynamic_linker=no
+  ;;
+
+linux*android*)
+  version_type=none # Android doesn't support versioned libraries.
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext'
+  soname_spec='$libname$release$shared_ext'
+  finish_cmds=
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+
+  # This implies no fast_install, which is unacceptable.
+  # Some rework will be needed to allow for fast_install
+  # before this can be enabled.
+  hardcode_into_libs=yes
+
+  dynamic_linker='Android linker'
+  # Don't embed -rpath directories since the linker doesn't support them.
+  hardcode_libdir_flag_spec='-L$libdir'
+  ;;
+
+# This must be glibc/ELF.
+linux* | k*bsd*-gnu | kopensolaris*-gnu | gnu*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  finish_cmds='PATH="\$PATH:/sbin" ldconfig -n $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+
+  # Some binutils ld are patched to set DT_RUNPATH
+  if test ${lt_cv_shlibpath_overrides_runpath+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) lt_cv_shlibpath_overrides_runpath=no
+    save_LDFLAGS=$LDFLAGS
+    save_libdir=$libdir
+    eval "libdir=/foo; wl=\"$lt_prog_compiler_wl\"; \
+	 LDFLAGS=\"\$LDFLAGS $hardcode_libdir_flag_spec\""
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  if  ($OBJDUMP -p conftest$ac_exeext) 2>/dev/null | grep "RUNPATH.*$libdir" >/dev/null
+then :
+  lt_cv_shlibpath_overrides_runpath=yes
+fi
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+    LDFLAGS=$save_LDFLAGS
+    libdir=$save_libdir
+     ;;
+esac
+fi
+
+  shlibpath_overrides_runpath=$lt_cv_shlibpath_overrides_runpath
+
+  # This implies no fast_install, which is unacceptable.
+  # Some rework will be needed to allow for fast_install
+  # before this can be enabled.
+  hardcode_into_libs=yes
+
+  # Ideally, we could use ldconfig to report *all* directores which are
+  # searched for libraries, however this is still not possible.  Aside from not
+  # being certain /sbin/ldconfig is available, command
+  # 'ldconfig -N -X -v | grep ^/' on 64bit Fedora does not report /usr/lib64,
+  # even though it is searched at run-time.  Try to do the best guess by
+  # appending ld.so.conf contents (and includes) to the search path.
+  if test -f /etc/ld.so.conf; then
+    lt_ld_extra=`awk '/^include / { system(sprintf("cd /etc; cat %s 2>/dev/null", \$2)); skip = 1; } { if (!skip) print \$0; skip = 0; }' < /etc/ld.so.conf | $SED -e 's/#.*//;/^[	 ]*hwcap[	 ]/d;s/[:,	]/ /g;s/=[^=]*$//;s/=[^= ]* / /g;s/"//g;/^$/d' | tr '\n' ' '`
+    sys_lib_dlsearch_path_spec="/lib /usr/lib $lt_ld_extra"
+  fi
+
+  # We used to test for /lib/ld.so.1 and disable shared libraries on
+  # powerpc, because MkLinux only supported shared libraries with the
+  # GNU dynamic linker.  Since this was broken with cross compilers,
+  # most powerpc-linux boxes support dynamic linking these days and
+  # people can always --disable-shared, the test was removed, and we
+  # assume the GNU/Linux dynamic linker is in use.
+  dynamic_linker='GNU/Linux ld.so'
+  ;;
+
+netbsd*)
+  version_type=sunos
+  need_lib_prefix=no
+  need_version=no
+  if echo __ELF__ | $CC -E - | $GREP __ELF__ >/dev/null; then
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+    finish_cmds='PATH="\$PATH:/sbin" ldconfig -m $libdir'
+    dynamic_linker='NetBSD (a.out) ld.so'
+  else
+    library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+    soname_spec='$libname$release$shared_ext$major'
+    dynamic_linker='NetBSD ld.elf_so'
+  fi
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  hardcode_into_libs=yes
+  ;;
+
+newsos6)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  ;;
+
+*nto* | *qnx*)
+  version_type=qnx
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  dynamic_linker='ldqnx.so'
+  ;;
+
+openbsd* | bitrig*)
+  version_type=sunos
+  sys_lib_dlsearch_path_spec=/usr/lib
+  need_lib_prefix=no
+  if test -z "`echo __ELF__ | $CC -E - | $GREP __ELF__`"; then
+    need_version=no
+  else
+    need_version=yes
+  fi
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+  finish_cmds='PATH="\$PATH:/sbin" ldconfig -m $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  ;;
+
+os2*)
+  libname_spec='$name'
+  version_type=windows
+  shrext_cmds=.dll
+  need_version=no
+  need_lib_prefix=no
+  # OS/2 can only load a DLL with a base name of 8 characters or less.
+  soname_spec='`test -n "$os2dllname" && libname="$os2dllname";
+    v=$($ECHO $release$versuffix | tr -d .-);
+    n=$($ECHO $libname | cut -b -$((8 - ${#v})) | tr . _);
+    $ECHO $n$v`$shared_ext'
+  library_names_spec='${libname}_dll.$libext'
+  dynamic_linker='OS/2 ld.exe'
+  shlibpath_var=BEGINLIBPATH
+  sys_lib_search_path_spec="/lib /usr/lib /usr/local/lib"
+  sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
+  postinstall_cmds='base_file=`basename \$file`~
+    dlpath=`$SHELL 2>&1 -c '\''. $dir/'\''\$base_file'\''i; $ECHO \$dlname'\''`~
+    dldir=$destdir/`dirname \$dlpath`~
+    test -d \$dldir || mkdir -p \$dldir~
+    $install_prog $dir/$dlname \$dldir/$dlname~
+    chmod a+x \$dldir/$dlname~
+    if test -n '\''$stripme'\'' && test -n '\''$striplib'\''; then
+      eval '\''$striplib \$dldir/$dlname'\'' || exit \$?;
+    fi'
+  postuninstall_cmds='dldll=`$SHELL 2>&1 -c '\''. $file; $ECHO \$dlname'\''`~
+    dlpath=$dir/\$dldll~
+    $RM \$dlpath'
+  ;;
+
+osf3* | osf4* | osf5*)
+  version_type=osf
+  need_lib_prefix=no
+  need_version=no
+  soname_spec='$libname$release$shared_ext$major'
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  shlibpath_var=LD_LIBRARY_PATH
+  sys_lib_search_path_spec="/usr/shlib /usr/ccs/lib /usr/lib/cmplrs/cc /usr/lib /usr/local/lib /var/shlib"
+  sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
+  ;;
+
+rdos*)
+  dynamic_linker=no
+  ;;
+
+solaris*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  hardcode_into_libs=yes
+  # ldd complains unless libraries are executable
+  postinstall_cmds='chmod +x $lib'
+  ;;
+
+sunos4*)
+  version_type=sunos
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$shared_ext$versuffix'
+  finish_cmds='PATH="\$PATH:/usr/etc" ldconfig $libdir'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  if test yes = "$with_gnu_ld"; then
+    need_lib_prefix=no
+  fi
+  need_version=yes
+  ;;
+
+sysv4 | sysv4.3*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  case $host_vendor in
+    sni)
+      shlibpath_overrides_runpath=no
+      need_lib_prefix=no
+      runpath_var=LD_RUN_PATH
+      ;;
+    siemens)
+      need_lib_prefix=no
+      ;;
+    motorola)
+      need_lib_prefix=no
+      need_version=no
+      shlibpath_overrides_runpath=no
+      sys_lib_search_path_spec='/lib /usr/lib /usr/ccs/lib'
+      ;;
+  esac
+  ;;
+
+sysv4*MP*)
+  if test -d /usr/nec; then
+    version_type=linux # correct to gnu/linux during the next big refactor
+    library_names_spec='$libname$shared_ext.$versuffix $libname$shared_ext.$major $libname$shared_ext'
+    soname_spec='$libname$shared_ext.$major'
+    shlibpath_var=LD_LIBRARY_PATH
+  fi
+  ;;
+
+sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX* | sysv4*uw2*)
+  version_type=sco
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=yes
+  hardcode_into_libs=yes
+  if test yes = "$with_gnu_ld"; then
+    sys_lib_search_path_spec='/usr/local/lib /usr/gnu/lib /usr/ccs/lib /usr/lib /lib'
+  else
+    sys_lib_search_path_spec='/usr/ccs/lib /usr/lib'
+    case $host_os in
+      sco3.2v5*)
+        sys_lib_search_path_spec="$sys_lib_search_path_spec /lib"
+	;;
+    esac
+  fi
+  sys_lib_dlsearch_path_spec='/usr/lib'
+  ;;
+
+tpf*)
+  # TPF is a cross-target only.  Preferred cross-host = GNU/Linux.
+  version_type=linux # correct to gnu/linux during the next big refactor
+  need_lib_prefix=no
+  need_version=no
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  shlibpath_var=LD_LIBRARY_PATH
+  shlibpath_overrides_runpath=no
+  hardcode_into_libs=yes
+  ;;
+
+uts4*)
+  version_type=linux # correct to gnu/linux during the next big refactor
+  library_names_spec='$libname$release$shared_ext$versuffix $libname$release$shared_ext$major $libname$shared_ext'
+  soname_spec='$libname$release$shared_ext$major'
+  shlibpath_var=LD_LIBRARY_PATH
+  ;;
+
+*)
+  dynamic_linker=no
+  ;;
+esac
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $dynamic_linker" >&5
+printf "%s\n" "$dynamic_linker" >&6; }
+test no = "$dynamic_linker" && can_build_shared=no
+
+variables_saved_for_relink="PATH $shlibpath_var $runpath_var"
+if test yes = "$GCC"; then
+  variables_saved_for_relink="$variables_saved_for_relink GCC_EXEC_PREFIX COMPILER_PATH LIBRARY_PATH"
+fi
+
+if test set = "${lt_cv_sys_lib_search_path_spec+set}"; then
+  sys_lib_search_path_spec=$lt_cv_sys_lib_search_path_spec
+fi
+
+if test set = "${lt_cv_sys_lib_dlsearch_path_spec+set}"; then
+  sys_lib_dlsearch_path_spec=$lt_cv_sys_lib_dlsearch_path_spec
+fi
+
+# remember unaugmented sys_lib_dlsearch_path content for libtool script decls...
+configure_time_dlsearch_path=$sys_lib_dlsearch_path_spec
+
+# ... but it needs LT_SYS_LIBRARY_PATH munging for other configure-time code
+func_munge_path_list sys_lib_dlsearch_path_spec "$LT_SYS_LIBRARY_PATH"
+
+# to be used as default LT_SYS_LIBRARY_PATH value in generated libtool
+configure_time_lt_sys_library_path=$LT_SYS_LIBRARY_PATH
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking how to hardcode library paths into programs" >&5
+printf %s "checking how to hardcode library paths into programs... " >&6; }
+hardcode_action=
+if test -n "$hardcode_libdir_flag_spec" ||
+   test -n "$runpath_var" ||
+   test yes = "$hardcode_automatic"; then
+
+  # We can hardcode non-existent directories.
+  if test no != "$hardcode_direct" &&
+     # If the only mechanism to avoid hardcoding is shlibpath_var, we
+     # have to relink, otherwise we might link with an installed library
+     # when we should be linking with a yet-to-be-installed one
+     ## test no != "$_LT_TAGVAR(hardcode_shlibpath_var, )" &&
+     test no != "$hardcode_minus_L"; then
+    # Linking always hardcodes the temporary library directory.
+    hardcode_action=relink
+  else
+    # We can link without hardcoding, and we can hardcode nonexisting dirs.
+    hardcode_action=immediate
+  fi
+else
+  # We cannot hardcode anything, or else we can only hardcode existing
+  # directories.
+  hardcode_action=unsupported
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $hardcode_action" >&5
+printf "%s\n" "$hardcode_action" >&6; }
+
+if test relink = "$hardcode_action" ||
+   test yes = "$inherit_rpath"; then
+  # Fast installation is not supported
+  enable_fast_install=no
+elif test yes = "$shlibpath_overrides_runpath" ||
+     test no = "$enable_shared"; then
+  # Fast installation is not necessary
+  enable_fast_install=needless
+fi
+
+
+
+
+
+
+  if test yes != "$enable_dlopen"; then
+  enable_dlopen=unknown
+  enable_dlopen_self=unknown
+  enable_dlopen_self_static=unknown
+else
+  lt_cv_dlopen=no
+  lt_cv_dlopen_libs=
+
+  case $host_os in
+  beos*)
+    lt_cv_dlopen=load_add_on
+    lt_cv_dlopen_libs=
+    lt_cv_dlopen_self=yes
+    ;;
+
+  mingw* | pw32* | cegcc*)
+    lt_cv_dlopen=LoadLibrary
+    lt_cv_dlopen_libs=
+    ;;
+
+  cygwin*)
+    lt_cv_dlopen=dlopen
+    lt_cv_dlopen_libs=
+    ;;
+
+  darwin*)
+    # if libdl is installed we need to link against it
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for dlopen in -ldl" >&5
+printf %s "checking for dlopen in -ldl... " >&6; }
+if test ${ac_cv_lib_dl_dlopen+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldl  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dlopen (void);
+int
+main (void)
+{
+return dlopen ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ac_cv_lib_dl_dlopen=yes
+else case e in #(
+  e) ac_cv_lib_dl_dlopen=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dl_dlopen" >&5
+printf "%s\n" "$ac_cv_lib_dl_dlopen" >&6; }
+if test "x$ac_cv_lib_dl_dlopen" = xyes
+then :
+  lt_cv_dlopen=dlopen lt_cv_dlopen_libs=-ldl
+else case e in #(
+  e)
+    lt_cv_dlopen=dyld
+    lt_cv_dlopen_libs=
+    lt_cv_dlopen_self=yes
+     ;;
+esac
+fi
+
+    ;;
+
+  tpf*)
+    # Don't try to run any link tests for TPF.  We know it's impossible
+    # because TPF is a cross-compiler, and we know how we open DSOs.
+    lt_cv_dlopen=dlopen
+    lt_cv_dlopen_libs=
+    lt_cv_dlopen_self=no
+    ;;
+
+  *)
+    ac_fn_c_check_func "$LINENO" "shl_load" "ac_cv_func_shl_load"
+if test "x$ac_cv_func_shl_load" = xyes
+then :
+  lt_cv_dlopen=shl_load
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for shl_load in -ldld" >&5
+printf %s "checking for shl_load in -ldld... " >&6; }
+if test ${ac_cv_lib_dld_shl_load+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldld  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char shl_load (void);
+int
+main (void)
+{
+return shl_load ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ac_cv_lib_dld_shl_load=yes
+else case e in #(
+  e) ac_cv_lib_dld_shl_load=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dld_shl_load" >&5
+printf "%s\n" "$ac_cv_lib_dld_shl_load" >&6; }
+if test "x$ac_cv_lib_dld_shl_load" = xyes
+then :
+  lt_cv_dlopen=shl_load lt_cv_dlopen_libs=-ldld
+else case e in #(
+  e) ac_fn_c_check_func "$LINENO" "dlopen" "ac_cv_func_dlopen"
+if test "x$ac_cv_func_dlopen" = xyes
+then :
+  lt_cv_dlopen=dlopen
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for dlopen in -ldl" >&5
+printf %s "checking for dlopen in -ldl... " >&6; }
+if test ${ac_cv_lib_dl_dlopen+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldl  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dlopen (void);
+int
+main (void)
+{
+return dlopen ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ac_cv_lib_dl_dlopen=yes
+else case e in #(
+  e) ac_cv_lib_dl_dlopen=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dl_dlopen" >&5
+printf "%s\n" "$ac_cv_lib_dl_dlopen" >&6; }
+if test "x$ac_cv_lib_dl_dlopen" = xyes
+then :
+  lt_cv_dlopen=dlopen lt_cv_dlopen_libs=-ldl
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for dlopen in -lsvld" >&5
+printf %s "checking for dlopen in -lsvld... " >&6; }
+if test ${ac_cv_lib_svld_dlopen+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_check_lib_save_LIBS=$LIBS
+LIBS="-lsvld  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dlopen (void);
+int
+main (void)
+{
+return dlopen ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ac_cv_lib_svld_dlopen=yes
+else case e in #(
+  e) ac_cv_lib_svld_dlopen=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_svld_dlopen" >&5
+printf "%s\n" "$ac_cv_lib_svld_dlopen" >&6; }
+if test "x$ac_cv_lib_svld_dlopen" = xyes
+then :
+  lt_cv_dlopen=dlopen lt_cv_dlopen_libs=-lsvld
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for dld_link in -ldld" >&5
+printf %s "checking for dld_link in -ldld... " >&6; }
+if test ${ac_cv_lib_dld_dld_link+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_check_lib_save_LIBS=$LIBS
+LIBS="-ldld  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char dld_link (void);
+int
+main (void)
+{
+return dld_link ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ac_cv_lib_dld_dld_link=yes
+else case e in #(
+  e) ac_cv_lib_dld_dld_link=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dld_dld_link" >&5
+printf "%s\n" "$ac_cv_lib_dld_dld_link" >&6; }
+if test "x$ac_cv_lib_dld_dld_link" = xyes
+then :
+  lt_cv_dlopen=dld_link lt_cv_dlopen_libs=-ldld
+fi
+
+	       ;;
+esac
+fi
+
+	     ;;
+esac
+fi
+
+	   ;;
+esac
+fi
+
+	 ;;
+esac
+fi
+
+       ;;
+esac
+fi
+
+    ;;
+  esac
+
+  if test no = "$lt_cv_dlopen"; then
+    enable_dlopen=no
+  else
+    enable_dlopen=yes
+  fi
+
+  case $lt_cv_dlopen in
+  dlopen)
+    save_CPPFLAGS=$CPPFLAGS
+    test yes = "$ac_cv_header_dlfcn_h" && CPPFLAGS="$CPPFLAGS -DHAVE_DLFCN_H"
+
+    save_LDFLAGS=$LDFLAGS
+    wl=$lt_prog_compiler_wl eval LDFLAGS=\"\$LDFLAGS $export_dynamic_flag_spec\"
+
+    save_LIBS=$LIBS
+    LIBS="$lt_cv_dlopen_libs $LIBS"
+
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether a program can dlopen itself" >&5
+printf %s "checking whether a program can dlopen itself... " >&6; }
+if test ${lt_cv_dlopen_self+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) 	  if test yes = "$cross_compiling"; then :
+  lt_cv_dlopen_self=cross
+else
+  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
+  lt_status=$lt_dlunknown
+  cat > conftest.$ac_ext <<_LT_EOF
+#line $LINENO "configure"
+#include "confdefs.h"
+
+#if HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif
+
+#include <stdio.h>
+
+#ifdef RTLD_GLOBAL
+#  define LT_DLGLOBAL		RTLD_GLOBAL
+#else
+#  ifdef DL_GLOBAL
+#    define LT_DLGLOBAL		DL_GLOBAL
+#  else
+#    define LT_DLGLOBAL		0
+#  endif
+#endif
+
+/* We may have to define LT_DLLAZY_OR_NOW in the command line if we
+   find out it does not work in some platform. */
+#ifndef LT_DLLAZY_OR_NOW
+#  ifdef RTLD_LAZY
+#    define LT_DLLAZY_OR_NOW		RTLD_LAZY
+#  else
+#    ifdef DL_LAZY
+#      define LT_DLLAZY_OR_NOW		DL_LAZY
+#    else
+#      ifdef RTLD_NOW
+#        define LT_DLLAZY_OR_NOW	RTLD_NOW
+#      else
+#        ifdef DL_NOW
+#          define LT_DLLAZY_OR_NOW	DL_NOW
+#        else
+#          define LT_DLLAZY_OR_NOW	0
+#        endif
+#      endif
+#    endif
+#  endif
+#endif
+
+/* When -fvisibility=hidden is used, assume the code has been annotated
+   correspondingly for the symbols needed.  */
+#if defined __GNUC__ && (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 3))
+int fnord () __attribute__((visibility("default")));
+#endif
+
+int fnord () { return 42; }
+int main ()
+{
+  void *self = dlopen (0, LT_DLGLOBAL|LT_DLLAZY_OR_NOW);
+  int status = $lt_dlunknown;
+
+  if (self)
+    {
+      if (dlsym (self,"fnord"))       status = $lt_dlno_uscore;
+      else
+        {
+	  if (dlsym( self,"_fnord"))  status = $lt_dlneed_uscore;
+          else puts (dlerror ());
+	}
+      /* dlclose (self); */
+    }
+  else
+    puts (dlerror ());
+
+  return status;
+}
+_LT_EOF
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_link\""; } >&5
+  (eval $ac_link) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && test -s "conftest$ac_exeext" 2>/dev/null; then
+    (./conftest; exit; ) >&5 2>/dev/null
+    lt_status=$?
+    case x$lt_status in
+      x$lt_dlno_uscore) lt_cv_dlopen_self=yes ;;
+      x$lt_dlneed_uscore) lt_cv_dlopen_self=yes ;;
+      x$lt_dlunknown|x*) lt_cv_dlopen_self=no ;;
+    esac
+  else :
+    # compilation failed
+    lt_cv_dlopen_self=no
+  fi
+fi
+rm -fr conftest*
+
+     ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_dlopen_self" >&5
+printf "%s\n" "$lt_cv_dlopen_self" >&6; }
+
+    if test yes = "$lt_cv_dlopen_self"; then
+      wl=$lt_prog_compiler_wl eval LDFLAGS=\"\$LDFLAGS $lt_prog_compiler_static\"
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether a statically linked program can dlopen itself" >&5
+printf %s "checking whether a statically linked program can dlopen itself... " >&6; }
+if test ${lt_cv_dlopen_self_static+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) 	  if test yes = "$cross_compiling"; then :
+  lt_cv_dlopen_self_static=cross
+else
+  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
+  lt_status=$lt_dlunknown
+  cat > conftest.$ac_ext <<_LT_EOF
+#line $LINENO "configure"
+#include "confdefs.h"
+
+#if HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif
+
+#include <stdio.h>
+
+#ifdef RTLD_GLOBAL
+#  define LT_DLGLOBAL		RTLD_GLOBAL
+#else
+#  ifdef DL_GLOBAL
+#    define LT_DLGLOBAL		DL_GLOBAL
+#  else
+#    define LT_DLGLOBAL		0
+#  endif
+#endif
+
+/* We may have to define LT_DLLAZY_OR_NOW in the command line if we
+   find out it does not work in some platform. */
+#ifndef LT_DLLAZY_OR_NOW
+#  ifdef RTLD_LAZY
+#    define LT_DLLAZY_OR_NOW		RTLD_LAZY
+#  else
+#    ifdef DL_LAZY
+#      define LT_DLLAZY_OR_NOW		DL_LAZY
+#    else
+#      ifdef RTLD_NOW
+#        define LT_DLLAZY_OR_NOW	RTLD_NOW
+#      else
+#        ifdef DL_NOW
+#          define LT_DLLAZY_OR_NOW	DL_NOW
+#        else
+#          define LT_DLLAZY_OR_NOW	0
+#        endif
+#      endif
+#    endif
+#  endif
+#endif
+
+/* When -fvisibility=hidden is used, assume the code has been annotated
+   correspondingly for the symbols needed.  */
+#if defined __GNUC__ && (((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 3))
+int fnord () __attribute__((visibility("default")));
+#endif
+
+int fnord () { return 42; }
+int main ()
+{
+  void *self = dlopen (0, LT_DLGLOBAL|LT_DLLAZY_OR_NOW);
+  int status = $lt_dlunknown;
+
+  if (self)
+    {
+      if (dlsym (self,"fnord"))       status = $lt_dlno_uscore;
+      else
+        {
+	  if (dlsym( self,"_fnord"))  status = $lt_dlneed_uscore;
+          else puts (dlerror ());
+	}
+      /* dlclose (self); */
+    }
+  else
+    puts (dlerror ());
+
+  return status;
+}
+_LT_EOF
+  if { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_link\""; } >&5
+  (eval $ac_link) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && test -s "conftest$ac_exeext" 2>/dev/null; then
+    (./conftest; exit; ) >&5 2>/dev/null
+    lt_status=$?
+    case x$lt_status in
+      x$lt_dlno_uscore) lt_cv_dlopen_self_static=yes ;;
+      x$lt_dlneed_uscore) lt_cv_dlopen_self_static=yes ;;
+      x$lt_dlunknown|x*) lt_cv_dlopen_self_static=no ;;
+    esac
+  else :
+    # compilation failed
+    lt_cv_dlopen_self_static=no
+  fi
+fi
+rm -fr conftest*
+
+       ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_dlopen_self_static" >&5
+printf "%s\n" "$lt_cv_dlopen_self_static" >&6; }
+    fi
+
+    CPPFLAGS=$save_CPPFLAGS
+    LDFLAGS=$save_LDFLAGS
+    LIBS=$save_LIBS
+    ;;
+  esac
+
+  case $lt_cv_dlopen_self in
+  yes|no) enable_dlopen_self=$lt_cv_dlopen_self ;;
+  *) enable_dlopen_self=unknown ;;
+  esac
+
+  case $lt_cv_dlopen_self_static in
+  yes|no) enable_dlopen_self_static=$lt_cv_dlopen_self_static ;;
+  *) enable_dlopen_self_static=unknown ;;
+  esac
+fi
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+striplib=
+old_striplib=
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether stripping libraries is possible" >&5
+printf %s "checking whether stripping libraries is possible... " >&6; }
+if test -z "$STRIP"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+else
+  if $STRIP -V 2>&1 | $GREP "GNU strip" >/dev/null; then
+    old_striplib="$STRIP --strip-debug"
+    striplib="$STRIP --strip-unneeded"
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+  else
+    case $host_os in
+    darwin*)
+      # FIXME - insert some real tests, host_os isn't really good enough
+      striplib="$STRIP -x"
+      old_striplib="$STRIP -S"
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+      ;;
+    freebsd*)
+      if $STRIP -V 2>&1 | $GREP "elftoolchain" >/dev/null; then
+        old_striplib="$STRIP --strip-debug"
+        striplib="$STRIP --strip-unneeded"
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+      else
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+      fi
+      ;;
+    *)
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+      ;;
+    esac
+  fi
+fi
+
+
+
+
+
+
+
+
+
+
+
+
+  # Report what library types will actually be built
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if libtool supports shared libraries" >&5
+printf %s "checking if libtool supports shared libraries... " >&6; }
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $can_build_shared" >&5
+printf "%s\n" "$can_build_shared" >&6; }
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether to build shared libraries" >&5
+printf %s "checking whether to build shared libraries... " >&6; }
+  test no = "$can_build_shared" && enable_shared=no
+
+  # On AIX, shared libraries and static libraries use the same namespace, and
+  # are all built from PIC.
+  case $host_os in
+  aix3*)
+    test yes = "$enable_shared" && enable_static=no
+    if test -n "$RANLIB"; then
+      archive_cmds="$archive_cmds~\$RANLIB \$lib"
+      postinstall_cmds='$RANLIB $lib'
+    fi
+    ;;
+
+  aix[4-9]*)
+    if test ia64 != "$host_cpu"; then
+      case $enable_shared,$with_aix_soname,$aix_use_runtimelinking in
+      yes,aix,yes) ;;			# shared object as lib.so file only
+      yes,svr4,*) ;;			# shared object as lib.so archive member only
+      yes,*) enable_static=no ;;	# shared object in lib.a archive as well
+      esac
+    fi
+    ;;
+  esac
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $enable_shared" >&5
+printf "%s\n" "$enable_shared" >&6; }
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether to build static libraries" >&5
+printf %s "checking whether to build static libraries... " >&6; }
+  # Make sure either enable_shared or enable_static is yes.
+  test yes = "$enable_shared" || enable_static=yes
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $enable_static" >&5
+printf "%s\n" "$enable_static" >&6; }
+
+
+
+
+fi
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+CC=$lt_save_CC
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+        ac_config_commands="$ac_config_commands libtool"
+
+
+
+
+# Only expand once:
+
+
+
+
+
+
+# Some awk implementations crash when confronted with pnglibconf.dfa.
+# Run a test now, to make sure this doesn't happen.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if awk ($AWK) works" >&5
+printf %s "checking if awk ($AWK) works... " >&6; }
+if ${AWK} -f ${srcdir}/scripts/options.awk out="/dev/null" version=search\
+   ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+   ${srcdir}/pngusr.dfa 1>&2
+then
+   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+else
+   { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+as_fn_error 1 "no
+See 'config.log' for more details" "$LINENO" 5; }
+fi
+
+# This is a remnant of the old cc -E validation, where it may have been
+# necessary to use a different preprocessor for .dfn files
+DFNCPP="$CPP"
+
+
+# Check whether --enable-tests was given.
+if test ${enable_tests+y}
+then :
+  enableval=$enable_tests; enable_tests="$enableval"
+else case e in #(
+  e) enable_tests=yes ;;
+esac
+fi
+
+
+ if test "$enable_tests" != "no"; then
+  ENABLE_TESTS_TRUE=
+  ENABLE_TESTS_FALSE='#'
+else
+  ENABLE_TESTS_TRUE='#'
+  ENABLE_TESTS_FALSE=
+fi
+
+
+# Check whether --enable-tools was given.
+if test ${enable_tools+y}
+then :
+  enableval=$enable_tools; enable_tools="$enableval"
+else case e in #(
+  e) enable_tools=yes ;;
+esac
+fi
+
+
+ if test "$enable_tools" != "no"; then
+  ENABLE_TOOLS_TRUE=
+  ENABLE_TOOLS_FALSE='#'
+else
+  ENABLE_TOOLS_TRUE='#'
+  ENABLE_TOOLS_FALSE=
+fi
+
+
+# -Werror cannot be passed to GCC in CFLAGS because configure will fail
+# (it checks the compiler with a program that generates a warning).
+# Add the following option to deal with this:
+
+# Check whether --enable-werror was given.
+if test ${enable_werror+y}
+then :
+  enableval=$enable_werror; test "$enable_werror" = "yes" && enable_werror="-Werror"
+    if test "$enable_werror" != "no"; then
+      sav_CFLAGS="$CFLAGS"
+      CFLAGS="$enable_werror $CFLAGS"
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if the compiler allows $enable_werror" >&5
+printf %s "checking if the compiler allows $enable_werror... " >&6; }
+      cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+            int main(int argc, char **argv){
+            return argv[argc-1][0];
+            }
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+         PNG_COPTS="$PNG_COPTS $enable_werror"
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; } ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+      CFLAGS="$sav_CFLAGS"
+    fi
+fi
+
+
+# For GCC 5 the default mode for C is -std=gnu11 instead of -std=gnu89.
+# In pngpriv.h we request just the POSIX 1003.1 and C89 APIs by defining
+# _POSIX_SOURCE to 1. This is incompatible with the new default mode, so
+# we test for that and force the "-std=c89" compiler option:
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if we need to force back C standard to C89" >&5
+printf %s "checking if we need to force back C standard to C89... " >&6; }
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+      #define _POSIX_SOURCE 1
+      #include <stdio.h>
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+else case e in #(
+  e)
+      if test "x$GCC" != "xyes"; then
+         as_fn_error $? "Forcing back to C89 is required but the flags are only known for GCC" "$LINENO" 5
+      fi
+   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+   CFLAGS="$CFLAGS -std=c89"
+ ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+
+# Checks for structures and compiler characteristics.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether struct tm is in sys/time.h or time.h" >&5
+printf %s "checking whether struct tm is in sys/time.h or time.h... " >&6; }
+if test ${ac_cv_struct_tm+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/types.h>
+#include <time.h>
+
+int
+main (void)
+{
+struct tm tm;
+				     int *p = &tm.tm_sec;
+				     return !p;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_struct_tm=time.h
+else case e in #(
+  e) ac_cv_struct_tm=sys/time.h ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_struct_tm" >&5
+printf "%s\n" "$ac_cv_struct_tm" >&6; }
+if test $ac_cv_struct_tm = sys/time.h; then
+
+printf "%s\n" "#define TM_IN_SYS_TIME 1" >>confdefs.h
+
+fi
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for C/C++ restrict keyword" >&5
+printf %s "checking for C/C++ restrict keyword... " >&6; }
+if test ${ac_cv_c_restrict+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_cv_c_restrict=no
+   # Put '__restrict__' first, to avoid problems with glibc and non-GCC; see:
+   # https://lists.gnu.org/archive/html/bug-autoconf/2016-02/msg00006.html
+   # Put 'restrict' last, because C++ lacks it.
+   for ac_kw in __restrict__ __restrict _Restrict restrict; do
+     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+typedef int *int_ptr;
+	   int foo (int_ptr $ac_kw ip) { return ip[0]; }
+	   int bar (int [$ac_kw]); /* Catch GCC bug 14050.  */
+	   int bar (int ip[$ac_kw]) { return ip[0]; }
+
+int
+main (void)
+{
+int s[1];
+	   int *$ac_kw t = s;
+	   t[0] = 0;
+	   return foo (t) + bar (t);
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_c_restrict=$ac_kw
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+     test "$ac_cv_c_restrict" != no && break
+   done
+   ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_c_restrict" >&5
+printf "%s\n" "$ac_cv_c_restrict" >&6; }
+
+ case $ac_cv_c_restrict in
+   restrict) ;;
+   no) printf "%s\n" "#define restrict /**/" >>confdefs.h
+ ;;
+   *)  printf "%s\n" "#define restrict $ac_cv_c_restrict" >>confdefs.h
+ ;;
+ esac
+
+
+# Checks for library functions.
+
+  for ac_func in pow
+do :
+  ac_fn_c_check_func "$LINENO" "pow" "ac_cv_func_pow"
+if test "x$ac_cv_func_pow" = xyes
+then :
+  printf "%s\n" "#define HAVE_POW 1" >>confdefs.h
+
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for pow in -lm" >&5
+printf %s "checking for pow in -lm... " >&6; }
+if test ${ac_cv_lib_m_pow+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_check_lib_save_LIBS=$LIBS
+LIBS="-lm  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char pow (void);
+int
+main (void)
+{
+return pow ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ac_cv_lib_m_pow=yes
+else case e in #(
+  e) ac_cv_lib_m_pow=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_m_pow" >&5
+printf "%s\n" "$ac_cv_lib_m_pow" >&6; }
+if test "x$ac_cv_lib_m_pow" = xyes
+then :
+  printf "%s\n" "#define HAVE_LIBM 1" >>confdefs.h
+
+  LIBS="-lm $LIBS"
+
+else case e in #(
+  e) as_fn_error $? "cannot find pow" "$LINENO" 5 ;;
+esac
+fi
+ ;;
+esac
+fi
+
+done
+
+# Some later POSIX 1003.1 functions are required for test programs, failure
+# here is soft (the corresponding test program is not built).
+ac_fn_c_check_func "$LINENO" "clock_gettime" "ac_cv_func_clock_gettime"
+if test "x$ac_cv_func_clock_gettime" = xyes
+then :
+
+else case e in #(
+  e) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: not building timepng" >&5
+printf "%s\n" "$as_me: WARNING: not building timepng" >&2;} ;;
+esac
+fi
+
+ if test "$ac_cv_func_clock_gettime" = "yes"; then
+  HAVE_CLOCK_GETTIME_TRUE=
+  HAVE_CLOCK_GETTIME_FALSE='#'
+else
+  HAVE_CLOCK_GETTIME_TRUE='#'
+  HAVE_CLOCK_GETTIME_FALSE=
+fi
+
+
+
+# Check whether --with-zlib-prefix was given.
+if test ${with_zlib_prefix+y}
+then :
+  withval=$with_zlib_prefix; ZPREFIX=${withval}
+else case e in #(
+  e) ZPREFIX='z_' ;;
+esac
+fi
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for zlibVersion in -lz" >&5
+printf %s "checking for zlibVersion in -lz... " >&6; }
+if test ${ac_cv_lib_z_zlibVersion+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_check_lib_save_LIBS=$LIBS
+LIBS="-lz  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char zlibVersion (void);
+int
+main (void)
+{
+return zlibVersion ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ac_cv_lib_z_zlibVersion=yes
+else case e in #(
+  e) ac_cv_lib_z_zlibVersion=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_z_zlibVersion" >&5
+printf "%s\n" "$ac_cv_lib_z_zlibVersion" >&6; }
+if test "x$ac_cv_lib_z_zlibVersion" = xyes
+then :
+  printf "%s\n" "#define HAVE_LIBZ 1" >>confdefs.h
+
+  LIBS="-lz $LIBS"
+
+else case e in #(
+  e) as_ac_Lib=`printf "%s\n" "ac_cv_lib_z_${ZPREFIX}zlibVersion" | sed "$as_sed_sh"`
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for ${ZPREFIX}zlibVersion in -lz" >&5
+printf %s "checking for ${ZPREFIX}zlibVersion in -lz... " >&6; }
+if eval test \${$as_ac_Lib+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_check_lib_save_LIBS=$LIBS
+LIBS="-lz  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char ${ZPREFIX}zlibVersion (void);
+int
+main (void)
+{
+return ${ZPREFIX}zlibVersion ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  eval "$as_ac_Lib=yes"
+else case e in #(
+  e) eval "$as_ac_Lib=no" ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS ;;
+esac
+fi
+eval ac_res=\$$as_ac_Lib
+	       { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+printf "%s\n" "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"
+then :
+  printf "%s\n" "#define HAVE_LIBZ 1" >>confdefs.h
+
+  LIBS="-lz $LIBS"
+
+else case e in #(
+  e) as_fn_error $? "zlib not installed" "$LINENO" 5 ;;
+esac
+fi
+ ;;
+esac
+fi
+
+
+# The following is for pngvalid, to ensure it catches FP errors even on
+# platforms that don't enable FP exceptions, the function appears in the math
+# library (typically), it's not an error if it is not found.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for feenableexcept in -lm" >&5
+printf %s "checking for feenableexcept in -lm... " >&6; }
+if test ${ac_cv_lib_m_feenableexcept+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) ac_check_lib_save_LIBS=$LIBS
+LIBS="-lm  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char feenableexcept (void);
+int
+main (void)
+{
+return feenableexcept ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ac_cv_lib_m_feenableexcept=yes
+else case e in #(
+  e) ac_cv_lib_m_feenableexcept=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_m_feenableexcept" >&5
+printf "%s\n" "$ac_cv_lib_m_feenableexcept" >&6; }
+if test "x$ac_cv_lib_m_feenableexcept" = xyes
+then :
+  printf "%s\n" "#define HAVE_LIBM 1" >>confdefs.h
+
+  LIBS="-lm $LIBS"
+
+fi
+
+ac_fn_c_check_func "$LINENO" "feenableexcept" "ac_cv_func_feenableexcept"
+if test "x$ac_cv_func_feenableexcept" = xyes
+then :
+  printf "%s\n" "#define HAVE_FEENABLEEXCEPT 1" >>confdefs.h
+
+fi
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if using Solaris linker" >&5
+printf %s "checking if using Solaris linker... " >&6; }
+SLD=`$LD --version 2>&1 | grep Solaris`
+if test "$SLD"; then
+    have_solaris_ld=yes
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+else
+    have_solaris_ld=no
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+ if test "$have_solaris_ld" = "yes"; then
+  HAVE_SOLARIS_LD_TRUE=
+  HAVE_SOLARIS_LD_FALSE='#'
+else
+  HAVE_SOLARIS_LD_TRUE='#'
+  HAVE_SOLARIS_LD_FALSE=
+fi
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if libraries can be versioned" >&5
+printf %s "checking if libraries can be versioned... " >&6; }
+# Special case for PE/COFF platforms: ld reports
+# support for version-script, but doesn't actually
+# DO anything with it.
+case $host in
+*cygwin* | *mingw32* | *interix* )
+    have_ld_version_script=no
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+;;
+* )
+
+if test "$have_solaris_ld" = "yes"; then
+    GLD=`$LD --help < /dev/null 2>&1 | grep 'M mapfile'`
+else
+    GLD=`$LD --help < /dev/null 2>/dev/null | grep version-script`
+fi
+
+if test "$GLD"; then
+    have_ld_version_script=yes
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+else
+    have_ld_version_script=no
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: *** You have not enabled versioned symbols." >&5
+printf "%s\n" "$as_me: WARNING: *** You have not enabled versioned symbols." >&2;}
+fi
+;;
+esac
+
+ if test "$have_ld_version_script" = "yes"; then
+  HAVE_LD_VERSION_SCRIPT_TRUE=
+  HAVE_LD_VERSION_SCRIPT_FALSE='#'
+else
+  HAVE_LD_VERSION_SCRIPT_TRUE='#'
+  HAVE_LD_VERSION_SCRIPT_FALSE=
+fi
+
+
+if test "$have_ld_version_script" = "yes"; then
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for symbol prefix" >&5
+printf %s "checking for symbol prefix... " >&6; }
+    SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
+                  | ${CPP:-${CC:-gcc} -E} - 2>&1 \
+                  | ${EGREP:-grep} "^PREFIX=" \
+                  | ${SED:-sed} -e "s:^PREFIX=::" -e "s:__USER_LABEL_PREFIX__::"`
+
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $SYMBOL_PREFIX" >&5
+printf "%s\n" "$SYMBOL_PREFIX" >&6; }
+fi
+
+# Substitutions for .in files
+
+
+
+
+
+# Additional arguments (and substitutions)
+# Allow the pkg-config directory to be set
+
+# Check whether --with-pkgconfigdir was given.
+if test ${with_pkgconfigdir+y}
+then :
+  withval=$with_pkgconfigdir; pkgconfigdir=${withval}
+else case e in #(
+  e) pkgconfigdir='${libdir}/pkgconfig' ;;
+esac
+fi
+
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: pkgconfig directory is ${pkgconfigdir}" >&5
+printf "%s\n" "$as_me: pkgconfig directory is ${pkgconfigdir}" >&6;}
+
+# Make the *-config binary config scripts optional
+
+# Check whether --with-binconfigs was given.
+if test ${with_binconfigs+y}
+then :
+  withval=$with_binconfigs; if test "${withval}" = no; then
+      binconfigs=
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: libpng-config scripts will not be built" >&5
+printf "%s\n" "$as_me: libpng-config scripts will not be built" >&6;}
+    else
+      binconfigs='${binconfigs}'
+    fi
+else case e in #(
+  e) binconfigs='${binconfigs}' ;;
+esac
+fi
+
+
+
+# Support for prefixes to the API function names; this will generate defines
+# at the start of the build to rename exported library functions
+
+# Check whether --with-libpng-prefix was given.
+if test ${with_libpng_prefix+y}
+then :
+  withval=$with_libpng_prefix; if test "${withval:-no}" != "no"; then
+      PNG_PREFIX=${withval}
+
+    fi
+fi
+
+ if test "${with_libpng_prefix:-no}" != "no"; then
+  DO_PNG_PREFIX_TRUE=
+  DO_PNG_PREFIX_FALSE='#'
+else
+  DO_PNG_PREFIX_TRUE='#'
+  DO_PNG_PREFIX_FALSE=
+fi
+
+
+# Control over what links are made for installed files.  Versioned files are
+# always installed, when the following options are turned on corresponding
+# unversioned links are also created (normally as symbolic links):
+# Check whether --enable-unversioned-links was given.
+if test ${enable_unversioned_links+y}
+then :
+  enableval=$enable_unversioned_links;
+fi
+
+
+# The AM_CONDITIONAL test is written so that the default is enabled;
+# --disable-unversioned-links must be given to turn the option off.
+ if test "$enable_unversioned_links" != "no"; then
+  DO_INSTALL_LINKS_TRUE=
+  DO_INSTALL_LINKS_FALSE='#'
+else
+  DO_INSTALL_LINKS_TRUE='#'
+  DO_INSTALL_LINKS_FALSE=
+fi
+
+
+# Check whether --enable-unversioned-libpng-pc was given.
+if test ${enable_unversioned_libpng_pc+y}
+then :
+  enableval=$enable_unversioned_libpng_pc;
+fi
+
+ if test "$enable_unversioned_libpng_pc" != "no"; then
+  DO_INSTALL_LIBPNG_PC_TRUE=
+  DO_INSTALL_LIBPNG_PC_FALSE='#'
+else
+  DO_INSTALL_LIBPNG_PC_TRUE='#'
+  DO_INSTALL_LIBPNG_PC_FALSE=
+fi
+
+
+# Check whether --enable-unversioned-libpng-config was given.
+if test ${enable_unversioned_libpng_config+y}
+then :
+  enableval=$enable_unversioned_libpng_config;
+fi
+
+ if test "$enable_unversioned_libpng_config" != "no"; then
+  DO_INSTALL_LIBPNG_CONFIG_TRUE=
+  DO_INSTALL_LIBPNG_CONFIG_FALSE='#'
+else
+  DO_INSTALL_LIBPNG_CONFIG_TRUE='#'
+  DO_INSTALL_LIBPNG_CONFIG_FALSE=
+fi
+
+
+# HOST-SPECIFIC OPTIONS
+# =====================
+#
+# DEFAULT
+# =======
+#
+# Check whether --enable-hardware-optimizations was given.
+if test ${enable_hardware_optimizations+y}
+then :
+  enableval=$enable_hardware_optimizations; case "$enableval" in
+      no|off)
+         # disable hardware optimization on all systems:
+         enable_arm_neon=no
+
+printf "%s\n" "#define PNG_ARM_NEON_OPT 0" >>confdefs.h
+
+         enable_mips_msa=no
+
+printf "%s\n" "#define PNG_MIPS_MSA_OPT 0" >>confdefs.h
+
+         enable_mips_mmi=no
+
+printf "%s\n" "#define PNG_MIPS_MMI_OPT 0" >>confdefs.h
+
+         enable_powerpc_vsx=no
+
+printf "%s\n" "#define PNG_POWERPC_VSX_OPT 0" >>confdefs.h
+
+         enable_intel_sse=no
+
+printf "%s\n" "#define PNG_INTEL_SSE_OPT 0" >>confdefs.h
+
+         enable_loongarch_lsx=no
+
+printf "%s\n" "#define PNG_LOONGARCH_LSX_OPT 0" >>confdefs.h
+
+         ;;
+      *)
+         # allow enabling hardware optimization on any system:
+         case "$host_cpu" in
+            arm*|aarch64*)
+              enable_arm_neon=yes
+
+printf "%s\n" "#define PNG_ARM_NEON_OPT 2" >>confdefs.h
+
+              ;;
+            mipsel*|mips64el*)
+              enable_mips_mmi=yes
+              enable_mips_msa=yes
+
+printf "%s\n" "#define PNG_MIPS_MMI_OPT 1" >>confdefs.h
+
+
+printf "%s\n" "#define PNG_MIPS_MSA_OPT 2" >>confdefs.h
+
+              ;;
+            i?86|x86_64)
+              enable_intel_sse=yes
+
+printf "%s\n" "#define PNG_INTEL_SSE_OPT 1" >>confdefs.h
+
+              ;;
+            powerpc*|ppc64*)
+              enable_powerpc_vsx=yes
+
+printf "%s\n" "#define PNG_POWERPC_VSX_OPT 2" >>confdefs.h
+
+              ;;
+            loongarch*)
+              enable_loongarch_lsx=yes
+
+printf "%s\n" "#define PNG_LOONGARCH_LSX_OPT 1" >>confdefs.h
+
+              ;;
+         esac
+         ;;
+   esac
+fi
+
+
+# ARM NEON
+# ========
+
+# Check whether --enable-arm-neon was given.
+if test ${enable_arm_neon+y}
+then :
+  enableval=$enable_arm_neon; case "$enableval" in
+      no|off)
+         # disable the default enabling on __ARM_NEON__ systems:
+
+printf "%s\n" "#define PNG_ARM_NEON_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the assembler files below:
+         enable_arm_neon=no ;;
+      check)
+
+printf "%s\n" "#define PNG_ARM_NEON_CHECK_SUPPORTED /**/" >>confdefs.h
+;;
+      api)
+
+printf "%s\n" "#define PNG_ARM_NEON_API_SUPPORTED /**/" >>confdefs.h
+;;
+      yes|on)
+
+printf "%s\n" "#define PNG_ARM_NEON_OPT 2" >>confdefs.h
+
+         { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: --enable-arm-neon: please specify 'check' or 'api';
+            if you want the optimizations unconditionally,
+            pass '-mfpu=neon' to the compiler." >&5
+printf "%s\n" "$as_me: WARNING: --enable-arm-neon: please specify 'check' or 'api';
+            if you want the optimizations unconditionally,
+            pass '-mfpu=neon' to the compiler." >&2;};;
+      *)
+         as_fn_error $? "--enable-arm-neon=${enable_arm_neon}:
+                      invalid argument" "$LINENO" 5
+   esac
+fi
+
+
+# Add ARM-specific files to all builds where $host_cpu is arm ('arm*') or
+# where ARM optimizations were explicitly requested. (This allows a fallback
+# if a future host CPU does not match 'arm*'.)
+
+ if test "$enable_arm_neon" != 'no' &&
+    case "$host_cpu" in
+      arm*|aarch64*) : ;;
+      *)    test "$enable_arm_neon" != '' ;;
+    esac; then
+  PNG_ARM_NEON_TRUE=
+  PNG_ARM_NEON_FALSE='#'
+else
+  PNG_ARM_NEON_TRUE='#'
+  PNG_ARM_NEON_FALSE=
+fi
+
+
+# MIPS MSA
+# ========
+
+# Check whether --enable-mips-msa was given.
+if test ${enable_mips_msa+y}
+then :
+  enableval=$enable_mips_msa; case "$enableval" in
+      no|off)
+         # disable the default enabling on __mips_msa systems:
+
+printf "%s\n" "#define PNG_MIPS_MSA_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the assembler files below:
+         enable_mips_msa=no ;;
+      check)
+
+printf "%s\n" "#define PNG_MIPS_MSA_CHECK_SUPPORTED /**/" >>confdefs.h
+;;
+      api)
+
+printf "%s\n" "#define PNG_MIPS_MSA_API_SUPPORTED /**/" >>confdefs.h
+;;
+      yes|on)
+
+printf "%s\n" "#define PNG_MIPS_MSA_OPT 2" >>confdefs.h
+
+         { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: --enable-mips-msa: please specify 'check' or 'api';
+            if you want the optimizations unconditionally,
+            pass '-mmsa -mfp64' to the compiler." >&5
+printf "%s\n" "$as_me: WARNING: --enable-mips-msa: please specify 'check' or 'api';
+            if you want the optimizations unconditionally,
+            pass '-mmsa -mfp64' to the compiler." >&2;};;
+      *)
+         as_fn_error $? "--enable-mips-msa=${enable_mips_msa}:
+                      invalid argument" "$LINENO" 5
+   esac
+fi
+
+
+# Add MIPS-specific files to all builds where $host_cpu is mips ('mips*') or
+# where MIPS optimizations were explicitly requested. (This allows a fallback
+# if a future host CPU does not match 'mips*'.)
+
+ if test "$enable_mips_msa" != 'no' &&
+    case "$host_cpu" in
+      mipsel*|mips64el*) : ;;
+    esac; then
+  PNG_MIPS_MSA_TRUE=
+  PNG_MIPS_MSA_FALSE='#'
+else
+  PNG_MIPS_MSA_TRUE='#'
+  PNG_MIPS_MSA_FALSE=
+fi
+
+
+# MIPS MMI
+# ========
+
+# Check whether --enable-mips-mmi was given.
+if test ${enable_mips_mmi+y}
+then :
+  enableval=$enable_mips_mmi; case "$enableval" in
+      no|off)
+         # disable the default enabling on __mips_mmi systems:
+
+printf "%s\n" "#define PNG_MIPS_MMI_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the assembler files below:
+         enable_mips_mmi=no;;
+      check)
+
+printf "%s\n" "#define PNG_MIPS_MMI_CHECK_SUPPORTED /**/" >>confdefs.h
+;;
+      api)
+
+printf "%s\n" "#define PNG_MIPS_MMI_API_SUPPORTED /**/" >>confdefs.h
+;;
+      yes|on)
+
+printf "%s\n" "#define PNG_MIPS_MMI_OPT 1" >>confdefs.h
+
+         { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: --enable-mips-mmi: please specify 'check' or 'api';
+            if you want the optimizations unconditionally
+            pass '-mloongson-mmi -march=loongson3a' to the compiler." >&5
+printf "%s\n" "$as_me: WARNING: --enable-mips-mmi: please specify 'check' or 'api';
+            if you want the optimizations unconditionally
+            pass '-mloongson-mmi -march=loongson3a' to the compiler." >&2;};;
+      *)
+         as_fn_error $? "--enable-mips-mmi=${enable_mips_mmi}:
+                      invalid argument" "$LINENO" 5
+   esac
+fi
+
+
+# Add MIPS specific files to all builds where the host_cpu is mips ('mips*') or
+# where MIPS optimizations were explicitly requested. (This allows a fallback
+# if a future host CPU does not match 'mips*'.)
+
+ if test "$enable_mips_mmi" != 'no' &&
+    case "$host_cpu" in
+      mipsel*|mips64el*) : ;;
+    esac; then
+  PNG_MIPS_MMI_TRUE=
+  PNG_MIPS_MMI_FALSE='#'
+else
+  PNG_MIPS_MMI_TRUE='#'
+  PNG_MIPS_MMI_FALSE=
+fi
+
+
+# INTEL SSE
+# =========
+
+# Check whether --enable-intel-sse was given.
+if test ${enable_intel_sse+y}
+then :
+  enableval=$enable_intel_sse; case "$enableval" in
+      no|off)
+         # disable the default enabling:
+
+printf "%s\n" "#define PNG_INTEL_SSE_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the assembler files below:
+         enable_intel_sse=no ;;
+      yes|on)
+
+printf "%s\n" "#define PNG_INTEL_SSE_OPT 1" >>confdefs.h
+;;
+      *)
+         as_fn_error $? "--enable-intel-sse=${enable_intel_sse}:
+                      invalid argument" "$LINENO" 5
+   esac
+fi
+
+
+# Add Intel-specific files to all builds where $host_cpu is Intel ('x86*') or
+# where Intel optimizations were explicitly requested. (This allows a fallback
+# if a future host CPU does not match 'x86*'.)
+ if test "$enable_intel_sse" != 'no' &&
+    case "$host_cpu" in
+      i?86|x86_64) : ;;
+      *)    test "$enable_intel_sse" != '' ;;
+    esac; then
+  PNG_INTEL_SSE_TRUE=
+  PNG_INTEL_SSE_FALSE='#'
+else
+  PNG_INTEL_SSE_TRUE='#'
+  PNG_INTEL_SSE_FALSE=
+fi
+
+
+# POWERPC VSX
+# ===========
+
+# Check whether --enable-powerpc-vsx was given.
+if test ${enable_powerpc_vsx+y}
+then :
+  enableval=$enable_powerpc_vsx; case "$enableval" in
+      no|off)
+         # disable the default enabling on __ppc64__ systems:
+
+printf "%s\n" "#define PNG_POWERPC_VSX_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the platform-specific files below:
+         enable_powerpc_vsx=no ;;
+      check)
+
+printf "%s\n" "#define PNG_POWERPC_VSX_CHECK_SUPPORTED /**/" >>confdefs.h
+
+         { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: --enable-powerpc-vsx: please see contrib/powerpc/README
+                     for the list of supported systems." >&5
+printf "%s\n" "$as_me: WARNING: --enable-powerpc-vsx: please see contrib/powerpc/README
+                     for the list of supported systems." >&2;};;
+      api)
+
+printf "%s\n" "#define PNG_POWERPC_VSX_API_SUPPORTED /**/" >>confdefs.h
+;;
+      yes|on)
+
+printf "%s\n" "#define PNG_POWERPC_VSX_OPT 2" >>confdefs.h
+
+         { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: --enable-powerpc-vsx: please specify 'check' or 'api';
+            if you want the optimizations unconditionally,
+            pass '-maltivec -mvsx' or '-mcpu=power8' to the compiler." >&5
+printf "%s\n" "$as_me: WARNING: --enable-powerpc-vsx: please specify 'check' or 'api';
+            if you want the optimizations unconditionally,
+            pass '-maltivec -mvsx' or '-mcpu=power8' to the compiler." >&2;};;
+      *)
+         as_fn_error $? "--enable-powerpc-vsx=${enable_powerpc_vsx}:
+                      invalid argument" "$LINENO" 5
+   esac
+fi
+
+
+# Add PowerPC-specific files to all builds where $host_cpu is powerpc
+# ('powerpc*') or where PowerPC optimizations were explicitly requested.
+# (This allows a fallback if a future host CPU does not match 'powerpc*'.)
+
+ if test "$enable_powerpc_vsx" != 'no' &&
+    case "$host_cpu" in
+      powerpc*|ppc64*) : ;;
+    esac; then
+  PNG_POWERPC_VSX_TRUE=
+  PNG_POWERPC_VSX_FALSE='#'
+else
+  PNG_POWERPC_VSX_TRUE='#'
+  PNG_POWERPC_VSX_FALSE=
+fi
+
+
+# LOONGARCH LSX
+# =============
+
+# Check whether --enable-loongarch-lsx was given.
+if test ${enable_loongarch_lsx+y}
+then :
+  enableval=$enable_loongarch_lsx; case "$enableval" in
+      no|off)
+         # disable the default enabling on __loongarch_simd systems:
+
+printf "%s\n" "#define PNG_LOONGARCH_LSX_OPT 0" >>confdefs.h
+
+         # Prevent inclusion of the assembler files below:
+         enable_loongarch_lsx=no;;
+      yes|on)
+
+printf "%s\n" "#define PNG_LOONGARCH_LSX_OPT 1" >>confdefs.h
+
+         ;;
+      *)
+         as_fn_error $? "--enable-loongarch-lsx=${enable_loongarch_lsx}:
+                      invalid argument" "$LINENO" 5
+   esac
+fi
+
+
+if test "$enable_loongarch_lsx" != "no" &&
+   case "$host_cpu" in
+      loongarch*) : ;;
+      *)    test "$enable_loongarch_lsx" != '' ;;
+   esac
+then
+   compiler_support_loongarch_lsx=no
+   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether to use LoongArch LSX intrinsics" >&5
+printf %s "checking whether to use LoongArch LSX intrinsics... " >&6; }
+   save_CFLAGS="$CFLAGS"
+   LSX_CFLAGS="${LSX_CFLAGS:-"-mlsx"}"
+   CFLAGS="$CFLAGS $LSX_CFLAGS"
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+#include <lsxintrin.h>
+int main(){
+   __m128i a, b, c;
+   a = __lsx_vadd_w(b, c);
+   return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  compiler_support_loongarch_lsx=yes
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+   CFLAGS="$save_CFLAGS"
+   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $compiler_support_loongarch_lsx" >&5
+printf "%s\n" "$compiler_support_loongarch_lsx" >&6; }
+   if test "$compiler_support_loongarch_lsx" = "yes"; then
+
+printf "%s\n" "#define PNG_LOONGARCH_LSX_OPT 1" >>confdefs.h
+
+   else
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: Compiler does not support loongarch LSX." >&5
+printf "%s\n" "$as_me: WARNING: Compiler does not support loongarch LSX." >&2;}
+   fi
+fi
+
+# Add LoongArch specific files to all builds where the host_cpu is loongarch
+# ('loongarch*') or where LoongArch optimizations were explicitly requested.
+# (This allows a fallback if a future host CPU does not match 'loongarch*'.)
+
+ if test "$enable_loongarch_lsx" != "no" &&
+    test "$compiler_support_loongarch_lsx" = "yes" &&
+    case "$host_cpu" in
+      loongarch*) : ;;
+      *)    test "$enable_loongarch_lsx" != '' ;;
+    esac; then
+  PNG_LOONGARCH_LSX_TRUE=
+  PNG_LOONGARCH_LSX_FALSE='#'
+else
+  PNG_LOONGARCH_LSX_TRUE='#'
+  PNG_LOONGARCH_LSX_FALSE=
+fi
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: Extra options for compiler: $PNG_COPTS" >&5
+printf "%s\n" "$as_me: Extra options for compiler: $PNG_COPTS" >&6;}
+
+# Config files, substituting as above
+ac_config_files="$ac_config_files Makefile libpng.pc:libpng.pc.in"
+
+ac_config_files="$ac_config_files libpng-config:libpng-config.in"
+
+
+cat >confcache <<\_ACEOF
+# This file is a shell script that caches the results of configure
+# tests run on this system so they can be shared between configure
+# scripts and configure runs, see configure's option --config-cache.
+# It is not useful on other systems.  If it contains results you don't
+# want to keep, you may remove or edit it.
+#
+# config.status only pays attention to the cache file if you give it
+# the --recheck option to rerun configure.
+#
+# 'ac_cv_env_foo' variables (set or unset) will be overridden when
+# loading this file, other *unset* 'ac_cv_foo' will be assigned the
+# following values.
+
+_ACEOF
+
+# The following way of writing the cache mishandles newlines in values,
+# but we know of no workaround that is simple, portable, and efficient.
+# So, we kill variables containing newlines.
+# Ultrix sh set writes to stderr and can't be redirected directly,
+# and sets the high bit in the cache file unless we assign to the vars.
+(
+  for ac_var in `(set) 2>&1 | sed -n 's/^\([a-zA-Z_][a-zA-Z0-9_]*\)=.*/\1/p'`; do
+    eval ac_val=\$$ac_var
+    case $ac_val in #(
+    *${as_nl}*)
+      case $ac_var in #(
+      *_cv_*) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
+printf "%s\n" "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
+      esac
+      case $ac_var in #(
+      _ | IFS | as_nl) ;; #(
+      BASH_ARGV | BASH_SOURCE) eval $ac_var= ;; #(
+      *) { eval $ac_var=; unset $ac_var;} ;;
+      esac ;;
+    esac
+  done
+
+  (set) 2>&1 |
+    case $as_nl`(ac_space=' '; set) 2>&1` in #(
+    *${as_nl}ac_space=\ *)
+      # 'set' does not quote correctly, so add quotes: double-quote
+      # substitution turns \\\\ into \\, and sed turns \\ into \.
+      sed -n \
+	"s/'/'\\\\''/g;
+	  s/^\\([_$as_cr_alnum]*_cv_[_$as_cr_alnum]*\\)=\\(.*\\)/\\1='\\2'/p"
+      ;; #(
+    *)
+      # 'set' quotes correctly as required by POSIX, so do not add quotes.
+      sed -n "/^[_$as_cr_alnum]*_cv_[_$as_cr_alnum]*=/p"
+      ;;
+    esac |
+    sort
+) |
+  sed '
+     /^ac_cv_env_/b end
+     t clear
+     :clear
+     s/^\([^=]*\)=\(.*[{}].*\)$/test ${\1+y} || &/
+     t end
+     s/^\([^=]*\)=\(.*\)$/\1=${\1=\2}/
+     :end' >>confcache
+if diff "$cache_file" confcache >/dev/null 2>&1; then :; else
+  if test -w "$cache_file"; then
+    if test "x$cache_file" != "x/dev/null"; then
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: updating cache $cache_file" >&5
+printf "%s\n" "$as_me: updating cache $cache_file" >&6;}
+      if test ! -f "$cache_file" || test -h "$cache_file"; then
+	cat confcache >"$cache_file"
+      else
+        case $cache_file in #(
+        */* | ?:*)
+	  mv -f confcache "$cache_file"$$ &&
+	  mv -f "$cache_file"$$ "$cache_file" ;; #(
+        *)
+	  mv -f confcache "$cache_file" ;;
+	esac
+      fi
+    fi
+  else
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: not updating unwritable cache $cache_file" >&5
+printf "%s\n" "$as_me: not updating unwritable cache $cache_file" >&6;}
+  fi
+fi
+rm -f confcache
+
+test "x$prefix" = xNONE && prefix=$ac_default_prefix
+# Let make expand exec_prefix.
+test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'
+
+DEFS=-DHAVE_CONFIG_H
+
+ac_libobjs=
+ac_ltlibobjs=
+U=
+for ac_i in : $LIBOBJS; do test "x$ac_i" = x: && continue
+  # 1. Remove the extension, and $U if already installed.
+  ac_script='s/\$U\././;s/\.o$//;s/\.obj$//'
+  ac_i=`printf "%s\n" "$ac_i" | sed "$ac_script"`
+  # 2. Prepend LIBOBJDIR.  When used with automake>=1.10 LIBOBJDIR
+  #    will be set to the directory where LIBOBJS objects are built.
+  as_fn_append ac_libobjs " \${LIBOBJDIR}$ac_i\$U.$ac_objext"
+  as_fn_append ac_ltlibobjs " \${LIBOBJDIR}$ac_i"'$U.lo'
+done
+LIBOBJS=$ac_libobjs
+
+LTLIBOBJS=$ac_ltlibobjs
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking that generated files are newer than configure" >&5
+printf %s "checking that generated files are newer than configure... " >&6; }
+   if test -n "$am_sleep_pid"; then
+     # Hide warnings about reused PIDs.
+     wait $am_sleep_pid 2>/dev/null
+   fi
+   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: done" >&5
+printf "%s\n" "done" >&6; }
+ if test -n "$EXEEXT"; then
+  am__EXEEXT_TRUE=
+  am__EXEEXT_FALSE='#'
+else
+  am__EXEEXT_TRUE='#'
+  am__EXEEXT_FALSE=
+fi
+
+if test -z "${MAINTAINER_MODE_TRUE}" && test -z "${MAINTAINER_MODE_FALSE}"; then
+  as_fn_error $? "conditional \"MAINTAINER_MODE\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${AMDEP_TRUE}" && test -z "${AMDEP_FALSE}"; then
+  as_fn_error $? "conditional \"AMDEP\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${am__fastdepCC_TRUE}" && test -z "${am__fastdepCC_FALSE}"; then
+  as_fn_error $? "conditional \"am__fastdepCC\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${am__fastdepCCAS_TRUE}" && test -z "${am__fastdepCCAS_FALSE}"; then
+  as_fn_error $? "conditional \"am__fastdepCCAS\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${ENABLE_TESTS_TRUE}" && test -z "${ENABLE_TESTS_FALSE}"; then
+  as_fn_error $? "conditional \"ENABLE_TESTS\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${ENABLE_TOOLS_TRUE}" && test -z "${ENABLE_TOOLS_FALSE}"; then
+  as_fn_error $? "conditional \"ENABLE_TOOLS\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${HAVE_CLOCK_GETTIME_TRUE}" && test -z "${HAVE_CLOCK_GETTIME_FALSE}"; then
+  as_fn_error $? "conditional \"HAVE_CLOCK_GETTIME\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${HAVE_SOLARIS_LD_TRUE}" && test -z "${HAVE_SOLARIS_LD_FALSE}"; then
+  as_fn_error $? "conditional \"HAVE_SOLARIS_LD\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${HAVE_LD_VERSION_SCRIPT_TRUE}" && test -z "${HAVE_LD_VERSION_SCRIPT_FALSE}"; then
+  as_fn_error $? "conditional \"HAVE_LD_VERSION_SCRIPT\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${DO_PNG_PREFIX_TRUE}" && test -z "${DO_PNG_PREFIX_FALSE}"; then
+  as_fn_error $? "conditional \"DO_PNG_PREFIX\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${DO_INSTALL_LINKS_TRUE}" && test -z "${DO_INSTALL_LINKS_FALSE}"; then
+  as_fn_error $? "conditional \"DO_INSTALL_LINKS\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${DO_INSTALL_LIBPNG_PC_TRUE}" && test -z "${DO_INSTALL_LIBPNG_PC_FALSE}"; then
+  as_fn_error $? "conditional \"DO_INSTALL_LIBPNG_PC\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${DO_INSTALL_LIBPNG_CONFIG_TRUE}" && test -z "${DO_INSTALL_LIBPNG_CONFIG_FALSE}"; then
+  as_fn_error $? "conditional \"DO_INSTALL_LIBPNG_CONFIG\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_ARM_NEON_TRUE}" && test -z "${PNG_ARM_NEON_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_ARM_NEON\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_MIPS_MSA_TRUE}" && test -z "${PNG_MIPS_MSA_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_MIPS_MSA\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_MIPS_MMI_TRUE}" && test -z "${PNG_MIPS_MMI_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_MIPS_MMI\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_INTEL_SSE_TRUE}" && test -z "${PNG_INTEL_SSE_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_INTEL_SSE\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_POWERPC_VSX_TRUE}" && test -z "${PNG_POWERPC_VSX_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_POWERPC_VSX\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${PNG_LOONGARCH_LSX_TRUE}" && test -z "${PNG_LOONGARCH_LSX_FALSE}"; then
+  as_fn_error $? "conditional \"PNG_LOONGARCH_LSX\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+
+: "${CONFIG_STATUS=./config.status}"
+ac_write_fail=0
+ac_clean_files_save=$ac_clean_files
+ac_clean_files="$ac_clean_files $CONFIG_STATUS"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: creating $CONFIG_STATUS" >&5
+printf "%s\n" "$as_me: creating $CONFIG_STATUS" >&6;}
+as_write_fail=0
+cat >$CONFIG_STATUS <<_ASEOF || as_write_fail=1
+#! $SHELL
+# Generated by $as_me.
+# Run this file to recreate the current configuration.
+# Compiler output produced by configure, useful for debugging
+# configure, is in config.log if it exists.
+
+debug=false
+ac_cs_recheck=false
+ac_cs_silent=false
+
+SHELL=\${CONFIG_SHELL-$SHELL}
+export SHELL
+_ASEOF
+cat >>$CONFIG_STATUS <<\_ASEOF || as_write_fail=1
+## -------------------- ##
+## M4sh Initialization. ##
+## -------------------- ##
+
+# Be more Bourne compatible
+DUALCASE=1; export DUALCASE # for MKS sh
+if test ${ZSH_VERSION+y} && (emulate sh) >/dev/null 2>&1
+then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else case e in #(
+  e) case `(set -o) 2>/dev/null` in #(
+  *posix*) :
+    set -o posix ;; #(
+  *) :
+     ;;
+esac ;;
+esac
+fi
+
+
+
+# Reset variables that may have inherited troublesome values from
+# the environment.
+
+# IFS needs to be set, to space, tab, and newline, in precisely that order.
+# (If _AS_PATH_WALK were called with IFS unset, it would have the
+# side effect of setting IFS to empty, thus disabling word splitting.)
+# Quoting is to prevent editors from complaining about space-tab.
+as_nl='
+'
+export as_nl
+IFS=" ""	$as_nl"
+
+PS1='$ '
+PS2='> '
+PS4='+ '
+
+# Ensure predictable behavior from utilities with locale-dependent output.
+LC_ALL=C
+export LC_ALL
+LANGUAGE=C
+export LANGUAGE
+
+# We cannot yet rely on "unset" to work, but we need these variables
+# to be unset--not just set to an empty or harmless value--now, to
+# avoid bugs in old shells (e.g. pre-3.0 UWIN ksh).  This construct
+# also avoids known problems related to "unset" and subshell syntax
+# in other old shells (e.g. bash 2.01 and pdksh 5.2.14).
+for as_var in BASH_ENV ENV MAIL MAILPATH CDPATH
+do eval test \${$as_var+y} \
+  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
+done
+
+# Ensure that fds 0, 1, and 2 are open.
+if (exec 3>&0) 2>/dev/null; then :; else exec 0</dev/null; fi
+if (exec 3>&1) 2>/dev/null; then :; else exec 1>/dev/null; fi
+if (exec 3>&2)            ; then :; else exec 2>/dev/null; fi
+
+# The user is always right.
+if ${PATH_SEPARATOR+false} :; then
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
+    (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
+      PATH_SEPARATOR=';'
+  }
+fi
+
+
+# Find who we are.  Look in the path if we contain no directory separator.
+as_myself=
+case $0 in #((
+  *[\\/]* ) as_myself=$0 ;;
+  *) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    test -r "$as_dir$0" && as_myself=$as_dir$0 && break
+  done
+IFS=$as_save_IFS
+
+     ;;
+esac
+# We did not find ourselves, most probably we were run as 'sh COMMAND'
+# in which case we are not to be found in the path.
+if test "x$as_myself" = x; then
+  as_myself=$0
+fi
+if test ! -f "$as_myself"; then
+  printf "%s\n" "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
+  exit 1
+fi
+
+
+
+# as_fn_error STATUS ERROR [LINENO LOG_FD]
+# ----------------------------------------
+# Output "`basename $0`: error: ERROR" to stderr. If LINENO and LOG_FD are
+# provided, also output the error to LOG_FD, referencing LINENO. Then exit the
+# script with STATUS, using 1 if that was 0.
+as_fn_error ()
+{
+  as_status=$1; test $as_status -eq 0 && as_status=1
+  if test "$4"; then
+    as_lineno=${as_lineno-"$3"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
+  fi
+  printf "%s\n" "$as_me: error: $2" >&2
+  as_fn_exit $as_status
+} # as_fn_error
+
+
+# as_fn_set_status STATUS
+# -----------------------
+# Set $? to STATUS, without forking.
+as_fn_set_status ()
+{
+  return $1
+} # as_fn_set_status
+
+# as_fn_exit STATUS
+# -----------------
+# Exit the shell with STATUS, even in a "trap 0" or "set -e" context.
+as_fn_exit ()
+{
+  set +e
+  as_fn_set_status $1
+  exit $1
+} # as_fn_exit
+
+# as_fn_unset VAR
+# ---------------
+# Portably unset VAR.
+as_fn_unset ()
+{
+  { eval $1=; unset $1;}
+}
+as_unset=as_fn_unset
+
+# as_fn_append VAR VALUE
+# ----------------------
+# Append the text in VALUE to the end of the definition contained in VAR. Take
+# advantage of any shell optimizations that allow amortized linear growth over
+# repeated appends, instead of the typical quadratic growth present in naive
+# implementations.
+if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null
+then :
+  eval 'as_fn_append ()
+  {
+    eval $1+=\$2
+  }'
+else case e in #(
+  e) as_fn_append ()
+  {
+    eval $1=\$$1\$2
+  } ;;
+esac
+fi # as_fn_append
+
+# as_fn_arith ARG...
+# ------------------
+# Perform arithmetic evaluation on the ARGs, and store the result in the
+# global $as_val. Take advantage of shells that can avoid forks. The arguments
+# must be portable across $(()) and expr.
+if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null
+then :
+  eval 'as_fn_arith ()
+  {
+    as_val=$(( $* ))
+  }'
+else case e in #(
+  e) as_fn_arith ()
+  {
+    as_val=`expr "$@" || test $? -eq 1`
+  } ;;
+esac
+fi # as_fn_arith
+
+
+if expr a : '\(a\)' >/dev/null 2>&1 &&
+   test "X`expr 00001 : '.*\(...\)'`" = X001; then
+  as_expr=expr
+else
+  as_expr=false
+fi
+
+if (basename -- /) >/dev/null 2>&1 && test "X`basename -- / 2>&1`" = "X/"; then
+  as_basename=basename
+else
+  as_basename=false
+fi
+
+if (as_dir=`dirname -- /` && test "X$as_dir" = X/) >/dev/null 2>&1; then
+  as_dirname=dirname
+else
+  as_dirname=false
+fi
+
+as_me=`$as_basename -- "$0" ||
+$as_expr X/"$0" : '.*/\([^/][^/]*\)/*$' \| \
+	 X"$0" : 'X\(//\)$' \| \
+	 X"$0" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X/"$0" |
+    sed '/^.*\/\([^/][^/]*\)\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+
+# Avoid depending upon Character Ranges.
+as_cr_letters='abcdefghijklmnopqrstuvwxyz'
+as_cr_LETTERS='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+as_cr_Letters=$as_cr_letters$as_cr_LETTERS
+as_cr_digits='0123456789'
+as_cr_alnum=$as_cr_Letters$as_cr_digits
+
+
+# Determine whether it's possible to make 'echo' print without a newline.
+# These variables are no longer used directly by Autoconf, but are AC_SUBSTed
+# for compatibility with existing Makefiles.
+ECHO_C= ECHO_N= ECHO_T=
+case `echo -n x` in #(((((
+-n*)
+  case `echo 'xy\c'` in
+  *c*) ECHO_T='	';;	# ECHO_T is single tab character.
+  xy)  ECHO_C='\c';;
+  *)   echo `echo ksh88 bug on AIX 6.1` > /dev/null
+       ECHO_T='	';;
+  esac;;
+*)
+  ECHO_N='-n';;
+esac
+
+# For backward compatibility with old third-party macros, we provide
+# the shell variables $as_echo and $as_echo_n.  New code should use
+# AS_ECHO(["message"]) and AS_ECHO_N(["message"]), respectively.
+as_echo='printf %s\n'
+as_echo_n='printf %s'
+
+rm -f conf$$ conf$$.exe conf$$.file
+if test -d conf$$.dir; then
+  rm -f conf$$.dir/conf$$.file
+else
+  rm -f conf$$.dir
+  mkdir conf$$.dir 2>/dev/null
+fi
+if (echo >conf$$.file) 2>/dev/null; then
+  if ln -s conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s='ln -s'
+    # ... but there are two gotchas:
+    # 1) On MSYS, both 'ln -s file dir' and 'ln file dir' fail.
+    # 2) DJGPP < 2.04 has no symlinks; 'ln -s' creates a wrapper executable.
+    # In both cases, we have to default to 'cp -pR'.
+    ln -s conf$$.file conf$$.dir 2>/dev/null && test ! -f conf$$.exe ||
+      as_ln_s='cp -pR'
+  elif ln conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s=ln
+  else
+    as_ln_s='cp -pR'
+  fi
+else
+  as_ln_s='cp -pR'
+fi
+rm -f conf$$ conf$$.exe conf$$.dir/conf$$.file conf$$.file
+rmdir conf$$.dir 2>/dev/null
+
+
+# as_fn_mkdir_p
+# -------------
+# Create "$as_dir" as a directory, including parents if necessary.
+as_fn_mkdir_p ()
+{
+
+  case $as_dir in #(
+  -*) as_dir=./$as_dir;;
+  esac
+  test -d "$as_dir" || eval $as_mkdir_p || {
+    as_dirs=
+    while :; do
+      case $as_dir in #(
+      *\'*) as_qdir=`printf "%s\n" "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
+      *) as_qdir=$as_dir;;
+      esac
+      as_dirs="'$as_qdir' $as_dirs"
+      as_dir=`$as_dirname -- "$as_dir" ||
+$as_expr X"$as_dir" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$as_dir" : 'X\(//\)[^/]' \| \
+	 X"$as_dir" : 'X\(//\)$' \| \
+	 X"$as_dir" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$as_dir" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+      test -d "$as_dir" && break
+    done
+    test -z "$as_dirs" || eval "mkdir $as_dirs"
+  } || test -d "$as_dir" || as_fn_error $? "cannot create directory $as_dir"
+
+
+} # as_fn_mkdir_p
+if mkdir -p . 2>/dev/null; then
+  as_mkdir_p='mkdir -p "$as_dir"'
+else
+  test -d ./-p && rmdir ./-p
+  as_mkdir_p=false
+fi
+
+
+# as_fn_executable_p FILE
+# -----------------------
+# Test if FILE is an executable regular file.
+as_fn_executable_p ()
+{
+  test -f "$1" && test -x "$1"
+} # as_fn_executable_p
+as_test_x='test -x'
+as_executable_p=as_fn_executable_p
+
+# Sed expression to map a string onto a valid CPP name.
+as_sed_cpp="y%*$as_cr_letters%P$as_cr_LETTERS%;s%[^_$as_cr_alnum]%_%g"
+as_tr_cpp="eval sed '$as_sed_cpp'" # deprecated
+
+# Sed expression to map a string onto a valid variable name.
+as_sed_sh="y%*+%pp%;s%[^_$as_cr_alnum]%_%g"
+as_tr_sh="eval sed '$as_sed_sh'" # deprecated
+
+
+exec 6>&1
+## ----------------------------------- ##
+## Main body of $CONFIG_STATUS script. ##
+## ----------------------------------- ##
+_ASEOF
+test $as_write_fail = 0 && chmod +x $CONFIG_STATUS || ac_write_fail=1
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+# Save the log message, to keep $0 and so on meaningful, and to
+# report actual input values of CONFIG_FILES etc. instead of their
+# values after options handling.
+ac_log="
+This file was extended by libpng $as_me 1.6.43, which was
+generated by GNU Autoconf 2.72.  Invocation command line was
+
+  CONFIG_FILES    = $CONFIG_FILES
+  CONFIG_HEADERS  = $CONFIG_HEADERS
+  CONFIG_LINKS    = $CONFIG_LINKS
+  CONFIG_COMMANDS = $CONFIG_COMMANDS
+  $ $0 $@
+
+on `(hostname || uname -n) 2>/dev/null | sed 1q`
+"
+
+_ACEOF
+
+case $ac_config_files in *"
+"*) set x $ac_config_files; shift; ac_config_files=$*;;
+esac
+
+case $ac_config_headers in *"
+"*) set x $ac_config_headers; shift; ac_config_headers=$*;;
+esac
+
+
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+# Files that config.status was made for.
+config_files="$ac_config_files"
+config_headers="$ac_config_headers"
+config_commands="$ac_config_commands"
+
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+ac_cs_usage="\
+'$as_me' instantiates files and other configuration actions
+from templates according to the current configuration.  Unless the files
+and actions are specified as TAGs, all are instantiated by default.
+
+Usage: $0 [OPTION]... [TAG]...
+
+  -h, --help       print this help, then exit
+  -V, --version    print version number and configuration settings, then exit
+      --config     print configuration, then exit
+  -q, --quiet, --silent
+                   do not print progress messages
+  -d, --debug      don't remove temporary files
+      --recheck    update $as_me by reconfiguring in the same conditions
+      --file=FILE[:TEMPLATE]
+                   instantiate the configuration file FILE
+      --header=FILE[:TEMPLATE]
+                   instantiate the configuration header FILE
+
+Configuration files:
+$config_files
+
+Configuration headers:
+$config_headers
+
+Configuration commands:
+$config_commands
+
+Report bugs to <png-mng-implement@lists.sourceforge.net>."
+
+_ACEOF
+ac_cs_config=`printf "%s\n" "$ac_configure_args" | sed "$ac_safe_unquote"`
+ac_cs_config_escaped=`printf "%s\n" "$ac_cs_config" | sed "s/^ //; s/'/'\\\\\\\\''/g"`
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+ac_cs_config='$ac_cs_config_escaped'
+ac_cs_version="\\
+libpng config.status 1.6.43
+configured by $0, generated by GNU Autoconf 2.72,
+  with options \\"\$ac_cs_config\\"
+
+Copyright (C) 2023 Free Software Foundation, Inc.
+This config.status script is free software; the Free Software Foundation
+gives unlimited permission to copy, distribute and modify it."
+
+ac_pwd='$ac_pwd'
+srcdir='$srcdir'
+INSTALL='$INSTALL'
+MKDIR_P='$MKDIR_P'
+AWK='$AWK'
+test -n "\$AWK" || AWK=awk
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+# The default lists apply if the user does not specify any file.
+ac_need_defaults=:
+while test $# != 0
+do
+  case $1 in
+  --*=?*)
+    ac_option=`expr "X$1" : 'X\([^=]*\)='`
+    ac_optarg=`expr "X$1" : 'X[^=]*=\(.*\)'`
+    ac_shift=:
+    ;;
+  --*=)
+    ac_option=`expr "X$1" : 'X\([^=]*\)='`
+    ac_optarg=
+    ac_shift=:
+    ;;
+  *)
+    ac_option=$1
+    ac_optarg=$2
+    ac_shift=shift
+    ;;
+  esac
+
+  case $ac_option in
+  # Handling of the options.
+  -recheck | --recheck | --rechec | --reche | --rech | --rec | --re | --r)
+    ac_cs_recheck=: ;;
+  --version | --versio | --versi | --vers | --ver | --ve | --v | -V )
+    printf "%s\n" "$ac_cs_version"; exit ;;
+  --config | --confi | --conf | --con | --co | --c )
+    printf "%s\n" "$ac_cs_config"; exit ;;
+  --debug | --debu | --deb | --de | --d | -d )
+    debug=: ;;
+  --file | --fil | --fi | --f )
+    $ac_shift
+    case $ac_optarg in
+    *\'*) ac_optarg=`printf "%s\n" "$ac_optarg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    '') as_fn_error $? "missing file argument" ;;
+    esac
+    as_fn_append CONFIG_FILES " '$ac_optarg'"
+    ac_need_defaults=false;;
+  --header | --heade | --head | --hea )
+    $ac_shift
+    case $ac_optarg in
+    *\'*) ac_optarg=`printf "%s\n" "$ac_optarg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    esac
+    as_fn_append CONFIG_HEADERS " '$ac_optarg'"
+    ac_need_defaults=false;;
+  --he | --h)
+    # Conflict between --help and --header
+    as_fn_error $? "ambiguous option: '$1'
+Try '$0 --help' for more information.";;
+  --help | --hel | -h )
+    printf "%s\n" "$ac_cs_usage"; exit ;;
+  -q | -quiet | --quiet | --quie | --qui | --qu | --q \
+  | -silent | --silent | --silen | --sile | --sil | --si | --s)
+    ac_cs_silent=: ;;
+
+  # This is an error.
+  -*) as_fn_error $? "unrecognized option: '$1'
+Try '$0 --help' for more information." ;;
+
+  *) as_fn_append ac_config_targets " $1"
+     ac_need_defaults=false ;;
+
+  esac
+  shift
+done
+
+ac_configure_extra_args=
+
+if $ac_cs_silent; then
+  exec 6>/dev/null
+  ac_configure_extra_args="$ac_configure_extra_args --silent"
+fi
+
+_ACEOF
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+if \$ac_cs_recheck; then
+  set X $SHELL '$0' $ac_configure_args \$ac_configure_extra_args --no-create --no-recursion
+  shift
+  \printf "%s\n" "running CONFIG_SHELL=$SHELL \$*" >&6
+  CONFIG_SHELL='$SHELL'
+  export CONFIG_SHELL
+  exec "\$@"
+fi
+
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+exec 5>>config.log
+{
+  echo
+  sed 'h;s/./-/g;s/^.../## /;s/...$/ ##/;p;x;p;x' <<_ASBOX
+## Running $as_me. ##
+_ASBOX
+  printf "%s\n" "$ac_log"
+} >&5
+
+_ACEOF
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+#
+# INIT-COMMANDS
+#
+AMDEP_TRUE="$AMDEP_TRUE" MAKE="${MAKE-make}"
+
+
+# The HP-UX ksh and POSIX shell print the target directory to stdout
+# if CDPATH is set.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+sed_quote_subst='$sed_quote_subst'
+double_quote_subst='$double_quote_subst'
+delay_variable_subst='$delay_variable_subst'
+SED='`$ECHO "$SED" | $SED "$delay_single_quote_subst"`'
+Xsed='`$ECHO "$Xsed" | $SED "$delay_single_quote_subst"`'
+GREP='`$ECHO "$GREP" | $SED "$delay_single_quote_subst"`'
+EGREP='`$ECHO "$EGREP" | $SED "$delay_single_quote_subst"`'
+FGREP='`$ECHO "$FGREP" | $SED "$delay_single_quote_subst"`'
+SHELL='`$ECHO "$SHELL" | $SED "$delay_single_quote_subst"`'
+ECHO='`$ECHO "$ECHO" | $SED "$delay_single_quote_subst"`'
+LD='`$ECHO "$LD" | $SED "$delay_single_quote_subst"`'
+macro_version='`$ECHO "$macro_version" | $SED "$delay_single_quote_subst"`'
+macro_revision='`$ECHO "$macro_revision" | $SED "$delay_single_quote_subst"`'
+AS='`$ECHO "$AS" | $SED "$delay_single_quote_subst"`'
+DLLTOOL='`$ECHO "$DLLTOOL" | $SED "$delay_single_quote_subst"`'
+OBJDUMP='`$ECHO "$OBJDUMP" | $SED "$delay_single_quote_subst"`'
+enable_shared='`$ECHO "$enable_shared" | $SED "$delay_single_quote_subst"`'
+enable_static='`$ECHO "$enable_static" | $SED "$delay_single_quote_subst"`'
+pic_mode='`$ECHO "$pic_mode" | $SED "$delay_single_quote_subst"`'
+enable_fast_install='`$ECHO "$enable_fast_install" | $SED "$delay_single_quote_subst"`'
+shared_archive_member_spec='`$ECHO "$shared_archive_member_spec" | $SED "$delay_single_quote_subst"`'
+PATH_SEPARATOR='`$ECHO "$PATH_SEPARATOR" | $SED "$delay_single_quote_subst"`'
+host_alias='`$ECHO "$host_alias" | $SED "$delay_single_quote_subst"`'
+host='`$ECHO "$host" | $SED "$delay_single_quote_subst"`'
+host_os='`$ECHO "$host_os" | $SED "$delay_single_quote_subst"`'
+build_alias='`$ECHO "$build_alias" | $SED "$delay_single_quote_subst"`'
+build='`$ECHO "$build" | $SED "$delay_single_quote_subst"`'
+build_os='`$ECHO "$build_os" | $SED "$delay_single_quote_subst"`'
+NM='`$ECHO "$NM" | $SED "$delay_single_quote_subst"`'
+LN_S='`$ECHO "$LN_S" | $SED "$delay_single_quote_subst"`'
+max_cmd_len='`$ECHO "$max_cmd_len" | $SED "$delay_single_quote_subst"`'
+ac_objext='`$ECHO "$ac_objext" | $SED "$delay_single_quote_subst"`'
+exeext='`$ECHO "$exeext" | $SED "$delay_single_quote_subst"`'
+lt_unset='`$ECHO "$lt_unset" | $SED "$delay_single_quote_subst"`'
+lt_SP2NL='`$ECHO "$lt_SP2NL" | $SED "$delay_single_quote_subst"`'
+lt_NL2SP='`$ECHO "$lt_NL2SP" | $SED "$delay_single_quote_subst"`'
+lt_cv_to_host_file_cmd='`$ECHO "$lt_cv_to_host_file_cmd" | $SED "$delay_single_quote_subst"`'
+lt_cv_to_tool_file_cmd='`$ECHO "$lt_cv_to_tool_file_cmd" | $SED "$delay_single_quote_subst"`'
+reload_flag='`$ECHO "$reload_flag" | $SED "$delay_single_quote_subst"`'
+reload_cmds='`$ECHO "$reload_cmds" | $SED "$delay_single_quote_subst"`'
+FILECMD='`$ECHO "$FILECMD" | $SED "$delay_single_quote_subst"`'
+deplibs_check_method='`$ECHO "$deplibs_check_method" | $SED "$delay_single_quote_subst"`'
+file_magic_cmd='`$ECHO "$file_magic_cmd" | $SED "$delay_single_quote_subst"`'
+file_magic_glob='`$ECHO "$file_magic_glob" | $SED "$delay_single_quote_subst"`'
+want_nocaseglob='`$ECHO "$want_nocaseglob" | $SED "$delay_single_quote_subst"`'
+sharedlib_from_linklib_cmd='`$ECHO "$sharedlib_from_linklib_cmd" | $SED "$delay_single_quote_subst"`'
+AR='`$ECHO "$AR" | $SED "$delay_single_quote_subst"`'
+lt_ar_flags='`$ECHO "$lt_ar_flags" | $SED "$delay_single_quote_subst"`'
+AR_FLAGS='`$ECHO "$AR_FLAGS" | $SED "$delay_single_quote_subst"`'
+archiver_list_spec='`$ECHO "$archiver_list_spec" | $SED "$delay_single_quote_subst"`'
+STRIP='`$ECHO "$STRIP" | $SED "$delay_single_quote_subst"`'
+RANLIB='`$ECHO "$RANLIB" | $SED "$delay_single_quote_subst"`'
+old_postinstall_cmds='`$ECHO "$old_postinstall_cmds" | $SED "$delay_single_quote_subst"`'
+old_postuninstall_cmds='`$ECHO "$old_postuninstall_cmds" | $SED "$delay_single_quote_subst"`'
+old_archive_cmds='`$ECHO "$old_archive_cmds" | $SED "$delay_single_quote_subst"`'
+lock_old_archive_extraction='`$ECHO "$lock_old_archive_extraction" | $SED "$delay_single_quote_subst"`'
+CC='`$ECHO "$CC" | $SED "$delay_single_quote_subst"`'
+CFLAGS='`$ECHO "$CFLAGS" | $SED "$delay_single_quote_subst"`'
+compiler='`$ECHO "$compiler" | $SED "$delay_single_quote_subst"`'
+GCC='`$ECHO "$GCC" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_pipe='`$ECHO "$lt_cv_sys_global_symbol_pipe" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_to_cdecl='`$ECHO "$lt_cv_sys_global_symbol_to_cdecl" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_to_import='`$ECHO "$lt_cv_sys_global_symbol_to_import" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_to_c_name_address='`$ECHO "$lt_cv_sys_global_symbol_to_c_name_address" | $SED "$delay_single_quote_subst"`'
+lt_cv_sys_global_symbol_to_c_name_address_lib_prefix='`$ECHO "$lt_cv_sys_global_symbol_to_c_name_address_lib_prefix" | $SED "$delay_single_quote_subst"`'
+lt_cv_nm_interface='`$ECHO "$lt_cv_nm_interface" | $SED "$delay_single_quote_subst"`'
+nm_file_list_spec='`$ECHO "$nm_file_list_spec" | $SED "$delay_single_quote_subst"`'
+lt_sysroot='`$ECHO "$lt_sysroot" | $SED "$delay_single_quote_subst"`'
+lt_cv_truncate_bin='`$ECHO "$lt_cv_truncate_bin" | $SED "$delay_single_quote_subst"`'
+objdir='`$ECHO "$objdir" | $SED "$delay_single_quote_subst"`'
+MAGIC_CMD='`$ECHO "$MAGIC_CMD" | $SED "$delay_single_quote_subst"`'
+lt_prog_compiler_no_builtin_flag='`$ECHO "$lt_prog_compiler_no_builtin_flag" | $SED "$delay_single_quote_subst"`'
+lt_prog_compiler_pic='`$ECHO "$lt_prog_compiler_pic" | $SED "$delay_single_quote_subst"`'
+lt_prog_compiler_wl='`$ECHO "$lt_prog_compiler_wl" | $SED "$delay_single_quote_subst"`'
+lt_prog_compiler_static='`$ECHO "$lt_prog_compiler_static" | $SED "$delay_single_quote_subst"`'
+lt_cv_prog_compiler_c_o='`$ECHO "$lt_cv_prog_compiler_c_o" | $SED "$delay_single_quote_subst"`'
+need_locks='`$ECHO "$need_locks" | $SED "$delay_single_quote_subst"`'
+MANIFEST_TOOL='`$ECHO "$MANIFEST_TOOL" | $SED "$delay_single_quote_subst"`'
+DSYMUTIL='`$ECHO "$DSYMUTIL" | $SED "$delay_single_quote_subst"`'
+NMEDIT='`$ECHO "$NMEDIT" | $SED "$delay_single_quote_subst"`'
+LIPO='`$ECHO "$LIPO" | $SED "$delay_single_quote_subst"`'
+OTOOL='`$ECHO "$OTOOL" | $SED "$delay_single_quote_subst"`'
+OTOOL64='`$ECHO "$OTOOL64" | $SED "$delay_single_quote_subst"`'
+libext='`$ECHO "$libext" | $SED "$delay_single_quote_subst"`'
+shrext_cmds='`$ECHO "$shrext_cmds" | $SED "$delay_single_quote_subst"`'
+extract_expsyms_cmds='`$ECHO "$extract_expsyms_cmds" | $SED "$delay_single_quote_subst"`'
+archive_cmds_need_lc='`$ECHO "$archive_cmds_need_lc" | $SED "$delay_single_quote_subst"`'
+enable_shared_with_static_runtimes='`$ECHO "$enable_shared_with_static_runtimes" | $SED "$delay_single_quote_subst"`'
+export_dynamic_flag_spec='`$ECHO "$export_dynamic_flag_spec" | $SED "$delay_single_quote_subst"`'
+whole_archive_flag_spec='`$ECHO "$whole_archive_flag_spec" | $SED "$delay_single_quote_subst"`'
+compiler_needs_object='`$ECHO "$compiler_needs_object" | $SED "$delay_single_quote_subst"`'
+old_archive_from_new_cmds='`$ECHO "$old_archive_from_new_cmds" | $SED "$delay_single_quote_subst"`'
+old_archive_from_expsyms_cmds='`$ECHO "$old_archive_from_expsyms_cmds" | $SED "$delay_single_quote_subst"`'
+archive_cmds='`$ECHO "$archive_cmds" | $SED "$delay_single_quote_subst"`'
+archive_expsym_cmds='`$ECHO "$archive_expsym_cmds" | $SED "$delay_single_quote_subst"`'
+module_cmds='`$ECHO "$module_cmds" | $SED "$delay_single_quote_subst"`'
+module_expsym_cmds='`$ECHO "$module_expsym_cmds" | $SED "$delay_single_quote_subst"`'
+with_gnu_ld='`$ECHO "$with_gnu_ld" | $SED "$delay_single_quote_subst"`'
+allow_undefined_flag='`$ECHO "$allow_undefined_flag" | $SED "$delay_single_quote_subst"`'
+no_undefined_flag='`$ECHO "$no_undefined_flag" | $SED "$delay_single_quote_subst"`'
+hardcode_libdir_flag_spec='`$ECHO "$hardcode_libdir_flag_spec" | $SED "$delay_single_quote_subst"`'
+hardcode_libdir_separator='`$ECHO "$hardcode_libdir_separator" | $SED "$delay_single_quote_subst"`'
+hardcode_direct='`$ECHO "$hardcode_direct" | $SED "$delay_single_quote_subst"`'
+hardcode_direct_absolute='`$ECHO "$hardcode_direct_absolute" | $SED "$delay_single_quote_subst"`'
+hardcode_minus_L='`$ECHO "$hardcode_minus_L" | $SED "$delay_single_quote_subst"`'
+hardcode_shlibpath_var='`$ECHO "$hardcode_shlibpath_var" | $SED "$delay_single_quote_subst"`'
+hardcode_automatic='`$ECHO "$hardcode_automatic" | $SED "$delay_single_quote_subst"`'
+inherit_rpath='`$ECHO "$inherit_rpath" | $SED "$delay_single_quote_subst"`'
+link_all_deplibs='`$ECHO "$link_all_deplibs" | $SED "$delay_single_quote_subst"`'
+always_export_symbols='`$ECHO "$always_export_symbols" | $SED "$delay_single_quote_subst"`'
+export_symbols_cmds='`$ECHO "$export_symbols_cmds" | $SED "$delay_single_quote_subst"`'
+exclude_expsyms='`$ECHO "$exclude_expsyms" | $SED "$delay_single_quote_subst"`'
+include_expsyms='`$ECHO "$include_expsyms" | $SED "$delay_single_quote_subst"`'
+prelink_cmds='`$ECHO "$prelink_cmds" | $SED "$delay_single_quote_subst"`'
+postlink_cmds='`$ECHO "$postlink_cmds" | $SED "$delay_single_quote_subst"`'
+file_list_spec='`$ECHO "$file_list_spec" | $SED "$delay_single_quote_subst"`'
+variables_saved_for_relink='`$ECHO "$variables_saved_for_relink" | $SED "$delay_single_quote_subst"`'
+need_lib_prefix='`$ECHO "$need_lib_prefix" | $SED "$delay_single_quote_subst"`'
+need_version='`$ECHO "$need_version" | $SED "$delay_single_quote_subst"`'
+version_type='`$ECHO "$version_type" | $SED "$delay_single_quote_subst"`'
+runpath_var='`$ECHO "$runpath_var" | $SED "$delay_single_quote_subst"`'
+shlibpath_var='`$ECHO "$shlibpath_var" | $SED "$delay_single_quote_subst"`'
+shlibpath_overrides_runpath='`$ECHO "$shlibpath_overrides_runpath" | $SED "$delay_single_quote_subst"`'
+libname_spec='`$ECHO "$libname_spec" | $SED "$delay_single_quote_subst"`'
+library_names_spec='`$ECHO "$library_names_spec" | $SED "$delay_single_quote_subst"`'
+soname_spec='`$ECHO "$soname_spec" | $SED "$delay_single_quote_subst"`'
+install_override_mode='`$ECHO "$install_override_mode" | $SED "$delay_single_quote_subst"`'
+postinstall_cmds='`$ECHO "$postinstall_cmds" | $SED "$delay_single_quote_subst"`'
+postuninstall_cmds='`$ECHO "$postuninstall_cmds" | $SED "$delay_single_quote_subst"`'
+finish_cmds='`$ECHO "$finish_cmds" | $SED "$delay_single_quote_subst"`'
+finish_eval='`$ECHO "$finish_eval" | $SED "$delay_single_quote_subst"`'
+hardcode_into_libs='`$ECHO "$hardcode_into_libs" | $SED "$delay_single_quote_subst"`'
+sys_lib_search_path_spec='`$ECHO "$sys_lib_search_path_spec" | $SED "$delay_single_quote_subst"`'
+configure_time_dlsearch_path='`$ECHO "$configure_time_dlsearch_path" | $SED "$delay_single_quote_subst"`'
+configure_time_lt_sys_library_path='`$ECHO "$configure_time_lt_sys_library_path" | $SED "$delay_single_quote_subst"`'
+hardcode_action='`$ECHO "$hardcode_action" | $SED "$delay_single_quote_subst"`'
+enable_dlopen='`$ECHO "$enable_dlopen" | $SED "$delay_single_quote_subst"`'
+enable_dlopen_self='`$ECHO "$enable_dlopen_self" | $SED "$delay_single_quote_subst"`'
+enable_dlopen_self_static='`$ECHO "$enable_dlopen_self_static" | $SED "$delay_single_quote_subst"`'
+old_striplib='`$ECHO "$old_striplib" | $SED "$delay_single_quote_subst"`'
+striplib='`$ECHO "$striplib" | $SED "$delay_single_quote_subst"`'
+
+LTCC='$LTCC'
+LTCFLAGS='$LTCFLAGS'
+compiler='$compiler_DEFAULT'
+
+# A function that is used when there is no print builtin or printf.
+func_fallback_echo ()
+{
+  eval 'cat <<_LTECHO_EOF
+\$1
+_LTECHO_EOF'
+}
+
+# Quote evaled strings.
+for var in SED \
+GREP \
+EGREP \
+FGREP \
+SHELL \
+ECHO \
+LD \
+AS \
+DLLTOOL \
+OBJDUMP \
+PATH_SEPARATOR \
+NM \
+LN_S \
+lt_SP2NL \
+lt_NL2SP \
+reload_flag \
+FILECMD \
+deplibs_check_method \
+file_magic_cmd \
+file_magic_glob \
+want_nocaseglob \
+sharedlib_from_linklib_cmd \
+AR \
+archiver_list_spec \
+STRIP \
+RANLIB \
+CC \
+CFLAGS \
+compiler \
+lt_cv_sys_global_symbol_pipe \
+lt_cv_sys_global_symbol_to_cdecl \
+lt_cv_sys_global_symbol_to_import \
+lt_cv_sys_global_symbol_to_c_name_address \
+lt_cv_sys_global_symbol_to_c_name_address_lib_prefix \
+lt_cv_nm_interface \
+nm_file_list_spec \
+lt_cv_truncate_bin \
+lt_prog_compiler_no_builtin_flag \
+lt_prog_compiler_pic \
+lt_prog_compiler_wl \
+lt_prog_compiler_static \
+lt_cv_prog_compiler_c_o \
+need_locks \
+MANIFEST_TOOL \
+DSYMUTIL \
+NMEDIT \
+LIPO \
+OTOOL \
+OTOOL64 \
+shrext_cmds \
+export_dynamic_flag_spec \
+whole_archive_flag_spec \
+compiler_needs_object \
+with_gnu_ld \
+allow_undefined_flag \
+no_undefined_flag \
+hardcode_libdir_flag_spec \
+hardcode_libdir_separator \
+exclude_expsyms \
+include_expsyms \
+file_list_spec \
+variables_saved_for_relink \
+libname_spec \
+library_names_spec \
+soname_spec \
+install_override_mode \
+finish_eval \
+old_striplib \
+striplib; do
+    case \`eval \\\\\$ECHO \\\\""\\\\\$\$var"\\\\"\` in
+    *[\\\\\\\`\\"\\\$]*)
+      eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"\\\$\$var\\" | \\\$SED \\"\\\$sed_quote_subst\\"\\\`\\\\\\"" ## exclude from sc_prohibit_nested_quotes
+      ;;
+    *)
+      eval "lt_\$var=\\\\\\"\\\$\$var\\\\\\""
+      ;;
+    esac
+done
+
+# Double-quote double-evaled strings.
+for var in reload_cmds \
+old_postinstall_cmds \
+old_postuninstall_cmds \
+old_archive_cmds \
+extract_expsyms_cmds \
+old_archive_from_new_cmds \
+old_archive_from_expsyms_cmds \
+archive_cmds \
+archive_expsym_cmds \
+module_cmds \
+module_expsym_cmds \
+export_symbols_cmds \
+prelink_cmds \
+postlink_cmds \
+postinstall_cmds \
+postuninstall_cmds \
+finish_cmds \
+sys_lib_search_path_spec \
+configure_time_dlsearch_path \
+configure_time_lt_sys_library_path; do
+    case \`eval \\\\\$ECHO \\\\""\\\\\$\$var"\\\\"\` in
+    *[\\\\\\\`\\"\\\$]*)
+      eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"\\\$\$var\\" | \\\$SED -e \\"\\\$double_quote_subst\\" -e \\"\\\$sed_quote_subst\\" -e \\"\\\$delay_variable_subst\\"\\\`\\\\\\"" ## exclude from sc_prohibit_nested_quotes
+      ;;
+    *)
+      eval "lt_\$var=\\\\\\"\\\$\$var\\\\\\""
+      ;;
+    esac
+done
+
+ac_aux_dir='$ac_aux_dir'
+
+# See if we are running on zsh, and set the options that allow our
+# commands through without removal of \ escapes INIT.
+if test -n "\${ZSH_VERSION+set}"; then
+   setopt NO_GLOB_SUBST
+fi
+
+
+    PACKAGE='$PACKAGE'
+    VERSION='$VERSION'
+    RM='$RM'
+    ofile='$ofile'
+
+
+
+
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+
+# Handling of arguments.
+for ac_config_target in $ac_config_targets
+do
+  case $ac_config_target in
+    "config.h") CONFIG_HEADERS="$CONFIG_HEADERS config.h" ;;
+    "depfiles") CONFIG_COMMANDS="$CONFIG_COMMANDS depfiles" ;;
+    "libtool") CONFIG_COMMANDS="$CONFIG_COMMANDS libtool" ;;
+    "Makefile") CONFIG_FILES="$CONFIG_FILES Makefile" ;;
+    "libpng.pc") CONFIG_FILES="$CONFIG_FILES libpng.pc:libpng.pc.in" ;;
+    "libpng-config") CONFIG_FILES="$CONFIG_FILES libpng-config:libpng-config.in" ;;
+
+  *) as_fn_error $? "invalid argument: '$ac_config_target'" "$LINENO" 5;;
+  esac
+done
+
+
+# If the user did not use the arguments to specify the items to instantiate,
+# then the envvar interface is used.  Set only those that are not.
+# We use the long form for the default assignment because of an extremely
+# bizarre bug on SunOS 4.1.3.
+if $ac_need_defaults; then
+  test ${CONFIG_FILES+y} || CONFIG_FILES=$config_files
+  test ${CONFIG_HEADERS+y} || CONFIG_HEADERS=$config_headers
+  test ${CONFIG_COMMANDS+y} || CONFIG_COMMANDS=$config_commands
+fi
+
+# Have a temporary directory for convenience.  Make it in the build tree
+# simply because there is no reason against having it here, and in addition,
+# creating and moving files from /tmp can sometimes cause problems.
+# Hook for its removal unless debugging.
+# Note that there is a small window in which the directory will not be cleaned:
+# after its creation but before its name has been assigned to '$tmp'.
+$debug ||
+{
+  tmp= ac_tmp=
+  trap 'exit_status=$?
+  : "${ac_tmp:=$tmp}"
+  { test ! -d "$ac_tmp" || rm -fr "$ac_tmp"; } && exit $exit_status
+' 0
+  trap 'as_fn_exit 1' 1 2 13 15
+}
+# Create a (secure) tmp directory for tmp files.
+
+{
+  tmp=`(umask 077 && mktemp -d "./confXXXXXX") 2>/dev/null` &&
+  test -d "$tmp"
+}  ||
+{
+  tmp=./conf$$-$RANDOM
+  (umask 077 && mkdir "$tmp")
+} || as_fn_error $? "cannot create a temporary directory in ." "$LINENO" 5
+ac_tmp=$tmp
+
+# Set up the scripts for CONFIG_FILES section.
+# No need to generate them if there are no CONFIG_FILES.
+# This happens for instance with './config.status config.h'.
+if test -n "$CONFIG_FILES"; then
+
+
+ac_cr=`echo X | tr X '\015'`
+# On cygwin, bash can eat \r inside `` if the user requested igncr.
+# But we know of no other shell where ac_cr would be empty at this
+# point, so we can use a bashism as a fallback.
+if test "x$ac_cr" = x; then
+  eval ac_cr=\$\'\\r\'
+fi
+ac_cs_awk_cr=`$AWK 'BEGIN { print "a\rb" }' </dev/null 2>/dev/null`
+if test "$ac_cs_awk_cr" = "a${ac_cr}b"; then
+  ac_cs_awk_cr='\\r'
+else
+  ac_cs_awk_cr=$ac_cr
+fi
+
+echo 'BEGIN {' >"$ac_tmp/subs1.awk" &&
+_ACEOF
+
+
+{
+  echo "cat >conf$$subs.awk <<_ACEOF" &&
+  echo "$ac_subst_vars" | sed 's/.*/&!$&$ac_delim/' &&
+  echo "_ACEOF"
+} >conf$$subs.sh ||
+  as_fn_error $? "could not make $CONFIG_STATUS" "$LINENO" 5
+ac_delim_num=`echo "$ac_subst_vars" | grep -c '^'`
+ac_delim='%!_!# '
+for ac_last_try in false false false false false :; do
+  . ./conf$$subs.sh ||
+    as_fn_error $? "could not make $CONFIG_STATUS" "$LINENO" 5
+
+  ac_delim_n=`sed -n "s/.*$ac_delim\$/X/p" conf$$subs.awk | grep -c X`
+  if test $ac_delim_n = $ac_delim_num; then
+    break
+  elif $ac_last_try; then
+    as_fn_error $? "could not make $CONFIG_STATUS" "$LINENO" 5
+  else
+    ac_delim="$ac_delim!$ac_delim _$ac_delim!! "
+  fi
+done
+rm -f conf$$subs.sh
+
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+cat >>"\$ac_tmp/subs1.awk" <<\\_ACAWK &&
+_ACEOF
+sed -n '
+h
+s/^/S["/; s/!.*/"]=/
+p
+g
+s/^[^!]*!//
+:repl
+t repl
+s/'"$ac_delim"'$//
+t delim
+:nl
+h
+s/\(.\{148\}\)..*/\1/
+t more1
+s/["\\]/\\&/g; s/^/"/; s/$/\\n"\\/
+p
+n
+b repl
+:more1
+s/["\\]/\\&/g; s/^/"/; s/$/"\\/
+p
+g
+s/.\{148\}//
+t nl
+:delim
+h
+s/\(.\{148\}\)..*/\1/
+t more2
+s/["\\]/\\&/g; s/^/"/; s/$/"/
+p
+b
+:more2
+s/["\\]/\\&/g; s/^/"/; s/$/"\\/
+p
+g
+s/.\{148\}//
+t delim
+' <conf$$subs.awk | sed '
+/^[^""]/{
+  N
+  s/\n//
+}
+' >>$CONFIG_STATUS || ac_write_fail=1
+rm -f conf$$subs.awk
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+_ACAWK
+cat >>"\$ac_tmp/subs1.awk" <<_ACAWK &&
+  for (key in S) S_is_set[key] = 1
+  FS = ""
+
+}
+{
+  line = $ 0
+  nfields = split(line, field, "@")
+  substed = 0
+  len = length(field[1])
+  for (i = 2; i < nfields; i++) {
+    key = field[i]
+    keylen = length(key)
+    if (S_is_set[key]) {
+      value = S[key]
+      line = substr(line, 1, len) "" value "" substr(line, len + keylen + 3)
+      len += length(value) + length(field[++i])
+      substed = 1
+    } else
+      len += 1 + keylen
+  }
+
+  print line
+}
+
+_ACAWK
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+if sed "s/$ac_cr//" < /dev/null > /dev/null 2>&1; then
+  sed "s/$ac_cr\$//; s/$ac_cr/$ac_cs_awk_cr/g"
+else
+  cat
+fi < "$ac_tmp/subs1.awk" > "$ac_tmp/subs.awk" \
+  || as_fn_error $? "could not setup config files machinery" "$LINENO" 5
+_ACEOF
+
+# VPATH may cause trouble with some makes, so we remove sole $(srcdir),
+# ${srcdir} and @srcdir@ entries from VPATH if srcdir is ".", strip leading and
+# trailing colons and then remove the whole line if VPATH becomes empty
+# (actually we leave an empty line to preserve line numbers).
+if test "x$srcdir" = x.; then
+  ac_vpsub='/^[	 ]*VPATH[	 ]*=[	 ]*/{
+h
+s///
+s/^/:/
+s/[	 ]*$/:/
+s/:\$(srcdir):/:/g
+s/:\${srcdir}:/:/g
+s/:@srcdir@:/:/g
+s/^:*//
+s/:*$//
+x
+s/\(=[	 ]*\).*/\1/
+G
+s/\n//
+s/^[^=]*=[	 ]*$//
+}'
+fi
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+fi # test -n "$CONFIG_FILES"
+
+# Set up the scripts for CONFIG_HEADERS section.
+# No need to generate them if there are no CONFIG_HEADERS.
+# This happens for instance with './config.status Makefile'.
+if test -n "$CONFIG_HEADERS"; then
+cat >"$ac_tmp/defines.awk" <<\_ACAWK ||
+BEGIN {
+_ACEOF
+
+# Transform confdefs.h into an awk script 'defines.awk', embedded as
+# here-document in config.status, that substitutes the proper values into
+# config.h.in to produce config.h.
+
+# Create a delimiter string that does not exist in confdefs.h, to ease
+# handling of long lines.
+ac_delim='%!_!# '
+for ac_last_try in false false :; do
+  ac_tt=`sed -n "/$ac_delim/p" confdefs.h`
+  if test -z "$ac_tt"; then
+    break
+  elif $ac_last_try; then
+    as_fn_error $? "could not make $CONFIG_HEADERS" "$LINENO" 5
+  else
+    ac_delim="$ac_delim!$ac_delim _$ac_delim!! "
+  fi
+done
+
+# For the awk script, D is an array of macro values keyed by name,
+# likewise P contains macro parameters if any.  Preserve backslash
+# newline sequences.
+
+ac_word_re=[_$as_cr_Letters][_$as_cr_alnum]*
+sed -n '
+s/.\{148\}/&'"$ac_delim"'/g
+t rset
+:rset
+s/^[	 ]*#[	 ]*define[	 ][	 ]*/ /
+t def
+d
+:def
+s/\\$//
+t bsnl
+s/["\\]/\\&/g
+s/^ \('"$ac_word_re"'\)\(([^()]*)\)[	 ]*\(.*\)/P["\1"]="\2"\
+D["\1"]=" \3"/p
+s/^ \('"$ac_word_re"'\)[	 ]*\(.*\)/D["\1"]=" \2"/p
+d
+:bsnl
+s/["\\]/\\&/g
+s/^ \('"$ac_word_re"'\)\(([^()]*)\)[	 ]*\(.*\)/P["\1"]="\2"\
+D["\1"]=" \3\\\\\\n"\\/p
+t cont
+s/^ \('"$ac_word_re"'\)[	 ]*\(.*\)/D["\1"]=" \2\\\\\\n"\\/p
+t cont
+d
+:cont
+n
+s/.\{148\}/&'"$ac_delim"'/g
+t clear
+:clear
+s/\\$//
+t bsnlc
+s/["\\]/\\&/g; s/^/"/; s/$/"/p
+d
+:bsnlc
+s/["\\]/\\&/g; s/^/"/; s/$/\\\\\\n"\\/p
+b cont
+' <confdefs.h | sed '
+s/'"$ac_delim"'/"\\\
+"/g' >>$CONFIG_STATUS || ac_write_fail=1
+
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+  for (key in D) D_is_set[key] = 1
+  FS = ""
+}
+/^[\t ]*#[\t ]*(define|undef)[\t ]+$ac_word_re([\t (]|\$)/ {
+  line = \$ 0
+  split(line, arg, " ")
+  if (arg[1] == "#") {
+    defundef = arg[2]
+    mac1 = arg[3]
+  } else {
+    defundef = substr(arg[1], 2)
+    mac1 = arg[2]
+  }
+  split(mac1, mac2, "(") #)
+  macro = mac2[1]
+  prefix = substr(line, 1, index(line, defundef) - 1)
+  if (D_is_set[macro]) {
+    # Preserve the white space surrounding the "#".
+    print prefix "define", macro P[macro] D[macro]
+    next
+  } else {
+    # Replace #undef with comments.  This is necessary, for example,
+    # in the case of _POSIX_SOURCE, which is predefined and required
+    # on some systems where configure will not decide to define it.
+    if (defundef == "undef") {
+      print "/*", prefix defundef, macro, "*/"
+      next
+    }
+  }
+}
+{ print }
+_ACAWK
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+  as_fn_error $? "could not setup config headers machinery" "$LINENO" 5
+fi # test -n "$CONFIG_HEADERS"
+
+
+eval set X "  :F $CONFIG_FILES  :H $CONFIG_HEADERS    :C $CONFIG_COMMANDS"
+shift
+for ac_tag
+do
+  case $ac_tag in
+  :[FHLC]) ac_mode=$ac_tag; continue;;
+  esac
+  case $ac_mode$ac_tag in
+  :[FHL]*:*);;
+  :L* | :C*:*) as_fn_error $? "invalid tag '$ac_tag'" "$LINENO" 5;;
+  :[FH]-) ac_tag=-:-;;
+  :[FH]*) ac_tag=$ac_tag:$ac_tag.in;;
+  esac
+  ac_save_IFS=$IFS
+  IFS=:
+  set x $ac_tag
+  IFS=$ac_save_IFS
+  shift
+  ac_file=$1
+  shift
+
+  case $ac_mode in
+  :L) ac_source=$1;;
+  :[FH])
+    ac_file_inputs=
+    for ac_f
+    do
+      case $ac_f in
+      -) ac_f="$ac_tmp/stdin";;
+      *) # Look for the file first in the build tree, then in the source tree
+	 # (if the path is not absolute).  The absolute path cannot be DOS-style,
+	 # because $ac_f cannot contain ':'.
+	 test -f "$ac_f" ||
+	   case $ac_f in
+	   [\\/$]*) false;;
+	   *) test -f "$srcdir/$ac_f" && ac_f="$srcdir/$ac_f";;
+	   esac ||
+	   as_fn_error 1 "cannot find input file: '$ac_f'" "$LINENO" 5;;
+      esac
+      case $ac_f in *\'*) ac_f=`printf "%s\n" "$ac_f" | sed "s/'/'\\\\\\\\''/g"`;; esac
+      as_fn_append ac_file_inputs " '$ac_f'"
+    done
+
+    # Let's still pretend it is 'configure' which instantiates (i.e., don't
+    # use $as_me), people would be surprised to read:
+    #    /* config.h.  Generated by config.status.  */
+    configure_input='Generated from '`
+	  printf "%s\n" "$*" | sed 's|^[^:]*/||;s|:[^:]*/|, |g'
+	`' by configure.'
+    if test x"$ac_file" != x-; then
+      configure_input="$ac_file.  $configure_input"
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: creating $ac_file" >&5
+printf "%s\n" "$as_me: creating $ac_file" >&6;}
+    fi
+    # Neutralize special characters interpreted by sed in replacement strings.
+    case $configure_input in #(
+    *\&* | *\|* | *\\* )
+       ac_sed_conf_input=`printf "%s\n" "$configure_input" |
+       sed 's/[\\\\&|]/\\\\&/g'`;; #(
+    *) ac_sed_conf_input=$configure_input;;
+    esac
+
+    case $ac_tag in
+    *:-:* | *:-) cat >"$ac_tmp/stdin" \
+      || as_fn_error $? "could not create $ac_file" "$LINENO" 5 ;;
+    esac
+    ;;
+  esac
+
+  ac_dir=`$as_dirname -- "$ac_file" ||
+$as_expr X"$ac_file" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$ac_file" : 'X\(//\)[^/]' \| \
+	 X"$ac_file" : 'X\(//\)$' \| \
+	 X"$ac_file" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$ac_file" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+  as_dir="$ac_dir"; as_fn_mkdir_p
+  ac_builddir=.
+
+case "$ac_dir" in
+.) ac_dir_suffix= ac_top_builddir_sub=. ac_top_build_prefix= ;;
+*)
+  ac_dir_suffix=/`printf "%s\n" "$ac_dir" | sed 's|^\.[\\/]||'`
+  # A ".." for each directory in $ac_dir_suffix.
+  ac_top_builddir_sub=`printf "%s\n" "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
+  case $ac_top_builddir_sub in
+  "") ac_top_builddir_sub=. ac_top_build_prefix= ;;
+  *)  ac_top_build_prefix=$ac_top_builddir_sub/ ;;
+  esac ;;
+esac
+ac_abs_top_builddir=$ac_pwd
+ac_abs_builddir=$ac_pwd$ac_dir_suffix
+# for backward compatibility:
+ac_top_builddir=$ac_top_build_prefix
+
+case $srcdir in
+  .)  # We are building in place.
+    ac_srcdir=.
+    ac_top_srcdir=$ac_top_builddir_sub
+    ac_abs_top_srcdir=$ac_pwd ;;
+  [\\/]* | ?:[\\/]* )  # Absolute name.
+    ac_srcdir=$srcdir$ac_dir_suffix;
+    ac_top_srcdir=$srcdir
+    ac_abs_top_srcdir=$srcdir ;;
+  *) # Relative name.
+    ac_srcdir=$ac_top_build_prefix$srcdir$ac_dir_suffix
+    ac_top_srcdir=$ac_top_build_prefix$srcdir
+    ac_abs_top_srcdir=$ac_pwd/$srcdir ;;
+esac
+ac_abs_srcdir=$ac_abs_top_srcdir$ac_dir_suffix
+
+
+  case $ac_mode in
+  :F)
+  #
+  # CONFIG_FILE
+  #
+
+  case $INSTALL in
+  [\\/$]* | ?:[\\/]* ) ac_INSTALL=$INSTALL ;;
+  *) ac_INSTALL=$ac_top_build_prefix$INSTALL ;;
+  esac
+  ac_MKDIR_P=$MKDIR_P
+  case $MKDIR_P in
+  [\\/$]* | ?:[\\/]* ) ;;
+  */*) ac_MKDIR_P=$ac_top_build_prefix$MKDIR_P ;;
+  esac
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+# If the template does not know about datarootdir, expand it.
+# FIXME: This hack should be removed a few years after 2.60.
+ac_datarootdir_hack=; ac_datarootdir_seen=
+ac_sed_dataroot='
+/datarootdir/ {
+  p
+  q
+}
+/@datadir@/p
+/@docdir@/p
+/@infodir@/p
+/@localedir@/p
+/@mandir@/p'
+case `eval "sed -n \"\$ac_sed_dataroot\" $ac_file_inputs"` in
+*datarootdir*) ac_datarootdir_seen=yes;;
+*@datadir@*|*@docdir@*|*@infodir@*|*@localedir@*|*@mandir@*)
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: $ac_file_inputs seems to ignore the --datarootdir setting" >&5
+printf "%s\n" "$as_me: WARNING: $ac_file_inputs seems to ignore the --datarootdir setting" >&2;}
+_ACEOF
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+  ac_datarootdir_hack='
+  s&@datadir@&$datadir&g
+  s&@docdir@&$docdir&g
+  s&@infodir@&$infodir&g
+  s&@localedir@&$localedir&g
+  s&@mandir@&$mandir&g
+  s&\\\${datarootdir}&$datarootdir&g' ;;
+esac
+_ACEOF
+
+# Neutralize VPATH when '$srcdir' = '.'.
+# Shell code in configure.ac might set extrasub.
+# FIXME: do we really want to maintain this feature?
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+ac_sed_extra="$ac_vpsub
+$extrasub
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+:t
+/@[a-zA-Z_][a-zA-Z_0-9]*@/!b
+s|@configure_input@|$ac_sed_conf_input|;t t
+s&@top_builddir@&$ac_top_builddir_sub&;t t
+s&@top_build_prefix@&$ac_top_build_prefix&;t t
+s&@srcdir@&$ac_srcdir&;t t
+s&@abs_srcdir@&$ac_abs_srcdir&;t t
+s&@top_srcdir@&$ac_top_srcdir&;t t
+s&@abs_top_srcdir@&$ac_abs_top_srcdir&;t t
+s&@builddir@&$ac_builddir&;t t
+s&@abs_builddir@&$ac_abs_builddir&;t t
+s&@abs_top_builddir@&$ac_abs_top_builddir&;t t
+s&@INSTALL@&$ac_INSTALL&;t t
+s&@MKDIR_P@&$ac_MKDIR_P&;t t
+$ac_datarootdir_hack
+"
+eval sed \"\$ac_sed_extra\" "$ac_file_inputs" | $AWK -f "$ac_tmp/subs.awk" \
+  >$ac_tmp/out || as_fn_error $? "could not create $ac_file" "$LINENO" 5
+
+test -z "$ac_datarootdir_hack$ac_datarootdir_seen" &&
+  { ac_out=`sed -n '/\${datarootdir}/p' "$ac_tmp/out"`; test -n "$ac_out"; } &&
+  { ac_out=`sed -n '/^[	 ]*datarootdir[	 ]*:*=/p' \
+      "$ac_tmp/out"`; test -z "$ac_out"; } &&
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: $ac_file contains a reference to the variable 'datarootdir'
+which seems to be undefined.  Please make sure it is defined" >&5
+printf "%s\n" "$as_me: WARNING: $ac_file contains a reference to the variable 'datarootdir'
+which seems to be undefined.  Please make sure it is defined" >&2;}
+
+  rm -f "$ac_tmp/stdin"
+  case $ac_file in
+  -) cat "$ac_tmp/out" && rm -f "$ac_tmp/out";;
+  *) rm -f "$ac_file" && mv "$ac_tmp/out" "$ac_file";;
+  esac \
+  || as_fn_error $? "could not create $ac_file" "$LINENO" 5
+ ;;
+  :H)
+  #
+  # CONFIG_HEADER
+  #
+  if test x"$ac_file" != x-; then
+    {
+      printf "%s\n" "/* $configure_input  */" >&1 \
+      && eval '$AWK -f "$ac_tmp/defines.awk"' "$ac_file_inputs"
+    } >"$ac_tmp/config.h" \
+      || as_fn_error $? "could not create $ac_file" "$LINENO" 5
+    if diff "$ac_file" "$ac_tmp/config.h" >/dev/null 2>&1; then
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: $ac_file is unchanged" >&5
+printf "%s\n" "$as_me: $ac_file is unchanged" >&6;}
+    else
+      rm -f "$ac_file"
+      mv "$ac_tmp/config.h" "$ac_file" \
+	|| as_fn_error $? "could not create $ac_file" "$LINENO" 5
+    fi
+  else
+    printf "%s\n" "/* $configure_input  */" >&1 \
+      && eval '$AWK -f "$ac_tmp/defines.awk"' "$ac_file_inputs" \
+      || as_fn_error $? "could not create -" "$LINENO" 5
+  fi
+# Compute "$ac_file"'s index in $config_headers.
+_am_arg="$ac_file"
+_am_stamp_count=1
+for _am_header in $config_headers :; do
+  case $_am_header in
+    $_am_arg | $_am_arg:* )
+      break ;;
+    * )
+      _am_stamp_count=`expr $_am_stamp_count + 1` ;;
+  esac
+done
+echo "timestamp for $_am_arg" >`$as_dirname -- "$_am_arg" ||
+$as_expr X"$_am_arg" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$_am_arg" : 'X\(//\)[^/]' \| \
+	 X"$_am_arg" : 'X\(//\)$' \| \
+	 X"$_am_arg" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$_am_arg" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`/stamp-h$_am_stamp_count
+ ;;
+
+  :C)  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: executing $ac_file commands" >&5
+printf "%s\n" "$as_me: executing $ac_file commands" >&6;}
+ ;;
+  esac
+
+
+  case $ac_file$ac_mode in
+    "depfiles":C) test x"$AMDEP_TRUE" != x"" || {
+  # Older Autoconf quotes --file arguments for eval, but not when files
+  # are listed without --file.  Let's play safe and only enable the eval
+  # if we detect the quoting.
+  # TODO: see whether this extra hack can be removed once we start
+  # requiring Autoconf 2.70 or later.
+  case $CONFIG_FILES in #(
+  *\'*) :
+    eval set x "$CONFIG_FILES" ;; #(
+  *) :
+    set x $CONFIG_FILES ;; #(
+  *) :
+     ;;
+esac
+  shift
+  # Used to flag and report bootstrapping failures.
+  am_rc=0
+  for am_mf
+  do
+    # Strip MF so we end up with the name of the file.
+    am_mf=`printf "%s\n" "$am_mf" | sed -e 's/:.*$//'`
+    # Check whether this is an Automake generated Makefile which includes
+    # dependency-tracking related rules and includes.
+    # Grep'ing the whole file directly is not great: AIX grep has a line
+    # limit of 2048, but all sed's we know have understand at least 4000.
+    sed -n 's,^am--depfiles:.*,X,p' "$am_mf" | grep X >/dev/null 2>&1 \
+      || continue
+    am_dirpart=`$as_dirname -- "$am_mf" ||
+$as_expr X"$am_mf" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$am_mf" : 'X\(//\)[^/]' \| \
+	 X"$am_mf" : 'X\(//\)$' \| \
+	 X"$am_mf" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$am_mf" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+    am_filepart=`$as_basename -- "$am_mf" ||
+$as_expr X/"$am_mf" : '.*/\([^/][^/]*\)/*$' \| \
+	 X"$am_mf" : 'X\(//\)$' \| \
+	 X"$am_mf" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X/"$am_mf" |
+    sed '/^.*\/\([^/][^/]*\)\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+    { echo "$as_me:$LINENO: cd "$am_dirpart" \
+      && sed -e '/# am--include-marker/d' "$am_filepart" \
+        | $MAKE -f - am--depfiles" >&5
+   (cd "$am_dirpart" \
+      && sed -e '/# am--include-marker/d' "$am_filepart" \
+        | $MAKE -f - am--depfiles) >&5 2>&5
+   ac_status=$?
+   echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); } || am_rc=$?
+  done
+  if test $am_rc -ne 0; then
+    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in '$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in '$ac_pwd':" >&2;}
+as_fn_error $? "Something went wrong bootstrapping makefile fragments
+    for automatic dependency tracking.  If GNU make was not used, consider
+    re-running the configure script with MAKE=\"gmake\" (or whatever is
+    necessary).  You can also try re-running configure with the
+    '--disable-dependency-tracking' option to at least be able to build
+    the package (albeit without support for automatic dependency tracking).
+See 'config.log' for more details" "$LINENO" 5; }
+  fi
+  { am_dirpart=; unset am_dirpart;}
+  { am_filepart=; unset am_filepart;}
+  { am_mf=; unset am_mf;}
+  { am_rc=; unset am_rc;}
+  rm -f conftest-deps.mk
+}
+ ;;
+    "libtool":C)
+
+    # See if we are running on zsh, and set the options that allow our
+    # commands through without removal of \ escapes.
+    if test -n "${ZSH_VERSION+set}"; then
+      setopt NO_GLOB_SUBST
+    fi
+
+    cfgfile=${ofile}T
+    trap "$RM \"$cfgfile\"; exit 1" 1 2 15
+    $RM "$cfgfile"
+
+    cat <<_LT_EOF >> "$cfgfile"
+#! $SHELL
+# Generated automatically by $as_me ($PACKAGE) $VERSION
+# Libtool was configured on host `(hostname || uname -n) 2>/dev/null | sed 1q`:
+# NOTE: Changes made to this file will be lost: look at ltmain.sh.
+
+# Provide generalized library-building support services.
+# Written by Gordon Matzigkeit, 1996
+
+# Copyright (C) 2014 Free Software Foundation, Inc.
+# This is free software; see the source for copying conditions.  There is NO
+# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+# GNU Libtool is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of of the License, or
+# (at your option) any later version.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program or library that is built
+# using GNU Libtool, you may include this file under the  same
+# distribution terms that you use for the rest of that program.
+#
+# GNU Libtool is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+# The names of the tagged configurations supported by this script.
+available_tags=''
+
+# Configured defaults for sys_lib_dlsearch_path munging.
+: \${LT_SYS_LIBRARY_PATH="$configure_time_lt_sys_library_path"}
+
+# ### BEGIN LIBTOOL CONFIG
+
+# A sed program that does not truncate output.
+SED=$lt_SED
+
+# Sed that helps us avoid accidentally triggering echo(1) options like -n.
+Xsed="\$SED -e 1s/^X//"
+
+# A grep program that handles long lines.
+GREP=$lt_GREP
+
+# An ERE matcher.
+EGREP=$lt_EGREP
+
+# A literal string matcher.
+FGREP=$lt_FGREP
+
+# Shell to use when invoking shell scripts.
+SHELL=$lt_SHELL
+
+# An echo program that protects backslashes.
+ECHO=$lt_ECHO
+
+# Which release of libtool.m4 was used?
+macro_version=$macro_version
+macro_revision=$macro_revision
+
+# Assembler program.
+AS=$lt_AS
+
+# DLL creation program.
+DLLTOOL=$lt_DLLTOOL
+
+# Object dumper program.
+OBJDUMP=$lt_OBJDUMP
+
+# Whether or not to build shared libraries.
+build_libtool_libs=$enable_shared
+
+# Whether or not to build static libraries.
+build_old_libs=$enable_static
+
+# What type of objects to build.
+pic_mode=$pic_mode
+
+# Whether or not to optimize for fast installation.
+fast_install=$enable_fast_install
+
+# Shared archive member basename,for filename based shared library versioning on AIX.
+shared_archive_member_spec=$shared_archive_member_spec
+
+# The PATH separator for the build system.
+PATH_SEPARATOR=$lt_PATH_SEPARATOR
+
+# The host system.
+host_alias=$host_alias
+host=$host
+host_os=$host_os
+
+# The build system.
+build_alias=$build_alias
+build=$build
+build_os=$build_os
+
+# A BSD- or MS-compatible name lister.
+NM=$lt_NM
+
+# Whether we need soft or hard links.
+LN_S=$lt_LN_S
+
+# What is the maximum length of a command?
+max_cmd_len=$max_cmd_len
+
+# Object file suffix (normally "o").
+objext=$ac_objext
+
+# Executable file suffix (normally "").
+exeext=$exeext
+
+# whether the shell understands "unset".
+lt_unset=$lt_unset
+
+# turn spaces into newlines.
+SP2NL=$lt_lt_SP2NL
+
+# turn newlines into spaces.
+NL2SP=$lt_lt_NL2SP
+
+# convert \$build file names to \$host format.
+to_host_file_cmd=$lt_cv_to_host_file_cmd
+
+# convert \$build files to toolchain format.
+to_tool_file_cmd=$lt_cv_to_tool_file_cmd
+
+# A file(cmd) program that detects file types.
+FILECMD=$lt_FILECMD
+
+# Method to check whether dependent libraries are shared objects.
+deplibs_check_method=$lt_deplibs_check_method
+
+# Command to use when deplibs_check_method = "file_magic".
+file_magic_cmd=$lt_file_magic_cmd
+
+# How to find potential files when deplibs_check_method = "file_magic".
+file_magic_glob=$lt_file_magic_glob
+
+# Find potential files using nocaseglob when deplibs_check_method = "file_magic".
+want_nocaseglob=$lt_want_nocaseglob
+
+# Command to associate shared and link libraries.
+sharedlib_from_linklib_cmd=$lt_sharedlib_from_linklib_cmd
+
+# The archiver.
+AR=$lt_AR
+
+# Flags to create an archive (by configure).
+lt_ar_flags=$lt_ar_flags
+
+# Flags to create an archive.
+AR_FLAGS=\${ARFLAGS-"\$lt_ar_flags"}
+
+# How to feed a file listing to the archiver.
+archiver_list_spec=$lt_archiver_list_spec
+
+# A symbol stripping program.
+STRIP=$lt_STRIP
+
+# Commands used to install an old-style archive.
+RANLIB=$lt_RANLIB
+old_postinstall_cmds=$lt_old_postinstall_cmds
+old_postuninstall_cmds=$lt_old_postuninstall_cmds
+
+# Whether to use a lock for old archive extraction.
+lock_old_archive_extraction=$lock_old_archive_extraction
+
+# A C compiler.
+LTCC=$lt_CC
+
+# LTCC compiler flags.
+LTCFLAGS=$lt_CFLAGS
+
+# Take the output of nm and produce a listing of raw symbols and C names.
+global_symbol_pipe=$lt_lt_cv_sys_global_symbol_pipe
+
+# Transform the output of nm in a proper C declaration.
+global_symbol_to_cdecl=$lt_lt_cv_sys_global_symbol_to_cdecl
+
+# Transform the output of nm into a list of symbols to manually relocate.
+global_symbol_to_import=$lt_lt_cv_sys_global_symbol_to_import
+
+# Transform the output of nm in a C name address pair.
+global_symbol_to_c_name_address=$lt_lt_cv_sys_global_symbol_to_c_name_address
+
+# Transform the output of nm in a C name address pair when lib prefix is needed.
+global_symbol_to_c_name_address_lib_prefix=$lt_lt_cv_sys_global_symbol_to_c_name_address_lib_prefix
+
+# The name lister interface.
+nm_interface=$lt_lt_cv_nm_interface
+
+# Specify filename containing input files for \$NM.
+nm_file_list_spec=$lt_nm_file_list_spec
+
+# The root where to search for dependent libraries,and where our libraries should be installed.
+lt_sysroot=$lt_sysroot
+
+# Command to truncate a binary pipe.
+lt_truncate_bin=$lt_lt_cv_truncate_bin
+
+# The name of the directory that contains temporary libtool files.
+objdir=$objdir
+
+# Used to examine libraries when file_magic_cmd begins with "file".
+MAGIC_CMD=$MAGIC_CMD
+
+# Must we lock files when doing compilation?
+need_locks=$lt_need_locks
+
+# Manifest tool.
+MANIFEST_TOOL=$lt_MANIFEST_TOOL
+
+# Tool to manipulate archived DWARF debug symbol files on Mac OS X.
+DSYMUTIL=$lt_DSYMUTIL
+
+# Tool to change global to local symbols on Mac OS X.
+NMEDIT=$lt_NMEDIT
+
+# Tool to manipulate fat objects and archives on Mac OS X.
+LIPO=$lt_LIPO
+
+# ldd/readelf like tool for Mach-O binaries on Mac OS X.
+OTOOL=$lt_OTOOL
+
+# ldd/readelf like tool for 64 bit Mach-O binaries on Mac OS X 10.4.
+OTOOL64=$lt_OTOOL64
+
+# Old archive suffix (normally "a").
+libext=$libext
+
+# Shared library suffix (normally ".so").
+shrext_cmds=$lt_shrext_cmds
+
+# The commands to extract the exported symbol list from a shared archive.
+extract_expsyms_cmds=$lt_extract_expsyms_cmds
+
+# Variables whose values should be saved in libtool wrapper scripts and
+# restored at link time.
+variables_saved_for_relink=$lt_variables_saved_for_relink
+
+# Do we need the "lib" prefix for modules?
+need_lib_prefix=$need_lib_prefix
+
+# Do we need a version for libraries?
+need_version=$need_version
+
+# Library versioning type.
+version_type=$version_type
+
+# Shared library runtime path variable.
+runpath_var=$runpath_var
+
+# Shared library path variable.
+shlibpath_var=$shlibpath_var
+
+# Is shlibpath searched before the hard-coded library search path?
+shlibpath_overrides_runpath=$shlibpath_overrides_runpath
+
+# Format of library name prefix.
+libname_spec=$lt_libname_spec
+
+# List of archive names.  First name is the real one, the rest are links.
+# The last name is the one that the linker finds with -lNAME
+library_names_spec=$lt_library_names_spec
+
+# The coded name of the library, if different from the real name.
+soname_spec=$lt_soname_spec
+
+# Permission mode override for installation of shared libraries.
+install_override_mode=$lt_install_override_mode
+
+# Command to use after installation of a shared archive.
+postinstall_cmds=$lt_postinstall_cmds
+
+# Command to use after uninstallation of a shared archive.
+postuninstall_cmds=$lt_postuninstall_cmds
+
+# Commands used to finish a libtool library installation in a directory.
+finish_cmds=$lt_finish_cmds
+
+# As "finish_cmds", except a single script fragment to be evaled but
+# not shown.
+finish_eval=$lt_finish_eval
+
+# Whether we should hardcode library paths into libraries.
+hardcode_into_libs=$hardcode_into_libs
+
+# Compile-time system search path for libraries.
+sys_lib_search_path_spec=$lt_sys_lib_search_path_spec
+
+# Detected run-time system search path for libraries.
+sys_lib_dlsearch_path_spec=$lt_configure_time_dlsearch_path
+
+# Explicit LT_SYS_LIBRARY_PATH set during ./configure time.
+configure_time_lt_sys_library_path=$lt_configure_time_lt_sys_library_path
+
+# Whether dlopen is supported.
+dlopen_support=$enable_dlopen
+
+# Whether dlopen of programs is supported.
+dlopen_self=$enable_dlopen_self
+
+# Whether dlopen of statically linked programs is supported.
+dlopen_self_static=$enable_dlopen_self_static
+
+# Commands to strip libraries.
+old_striplib=$lt_old_striplib
+striplib=$lt_striplib
+
+
+# The linker used to build libraries.
+LD=$lt_LD
+
+# How to create reloadable object files.
+reload_flag=$lt_reload_flag
+reload_cmds=$lt_reload_cmds
+
+# Commands used to build an old-style archive.
+old_archive_cmds=$lt_old_archive_cmds
+
+# A language specific compiler.
+CC=$lt_compiler
+
+# Is the compiler the GNU compiler?
+with_gcc=$GCC
+
+# Compiler flag to turn off builtin functions.
+no_builtin_flag=$lt_lt_prog_compiler_no_builtin_flag
+
+# Additional compiler flags for building library objects.
+pic_flag=$lt_lt_prog_compiler_pic
+
+# How to pass a linker flag through the compiler.
+wl=$lt_lt_prog_compiler_wl
+
+# Compiler flag to prevent dynamic linking.
+link_static_flag=$lt_lt_prog_compiler_static
+
+# Does compiler simultaneously support -c and -o options?
+compiler_c_o=$lt_lt_cv_prog_compiler_c_o
+
+# Whether or not to add -lc for building shared libraries.
+build_libtool_need_lc=$archive_cmds_need_lc
+
+# Whether or not to disallow shared libs when runtime libs are static.
+allow_libtool_libs_with_static_runtimes=$enable_shared_with_static_runtimes
+
+# Compiler flag to allow reflexive dlopens.
+export_dynamic_flag_spec=$lt_export_dynamic_flag_spec
+
+# Compiler flag to generate shared objects directly from archives.
+whole_archive_flag_spec=$lt_whole_archive_flag_spec
+
+# Whether the compiler copes with passing no objects directly.
+compiler_needs_object=$lt_compiler_needs_object
+
+# Create an old-style archive from a shared archive.
+old_archive_from_new_cmds=$lt_old_archive_from_new_cmds
+
+# Create a temporary old-style archive to link instead of a shared archive.
+old_archive_from_expsyms_cmds=$lt_old_archive_from_expsyms_cmds
+
+# Commands used to build a shared archive.
+archive_cmds=$lt_archive_cmds
+archive_expsym_cmds=$lt_archive_expsym_cmds
+
+# Commands used to build a loadable module if different from building
+# a shared archive.
+module_cmds=$lt_module_cmds
+module_expsym_cmds=$lt_module_expsym_cmds
+
+# Whether we are building with GNU ld or not.
+with_gnu_ld=$lt_with_gnu_ld
+
+# Flag that allows shared libraries with undefined symbols to be built.
+allow_undefined_flag=$lt_allow_undefined_flag
+
+# Flag that enforces no undefined symbols.
+no_undefined_flag=$lt_no_undefined_flag
+
+# Flag to hardcode \$libdir into a binary during linking.
+# This must work even if \$libdir does not exist
+hardcode_libdir_flag_spec=$lt_hardcode_libdir_flag_spec
+
+# Whether we need a single "-rpath" flag with a separated argument.
+hardcode_libdir_separator=$lt_hardcode_libdir_separator
+
+# Set to "yes" if using DIR/libNAME\$shared_ext during linking hardcodes
+# DIR into the resulting binary.
+hardcode_direct=$hardcode_direct
+
+# Set to "yes" if using DIR/libNAME\$shared_ext during linking hardcodes
+# DIR into the resulting binary and the resulting library dependency is
+# "absolute",i.e impossible to change by setting \$shlibpath_var if the
+# library is relocated.
+hardcode_direct_absolute=$hardcode_direct_absolute
+
+# Set to "yes" if using the -LDIR flag during linking hardcodes DIR
+# into the resulting binary.
+hardcode_minus_L=$hardcode_minus_L
+
+# Set to "yes" if using SHLIBPATH_VAR=DIR during linking hardcodes DIR
+# into the resulting binary.
+hardcode_shlibpath_var=$hardcode_shlibpath_var
+
+# Set to "yes" if building a shared library automatically hardcodes DIR
+# into the library and all subsequent libraries and executables linked
+# against it.
+hardcode_automatic=$hardcode_automatic
+
+# Set to yes if linker adds runtime paths of dependent libraries
+# to runtime path list.
+inherit_rpath=$inherit_rpath
+
+# Whether libtool must link a program against all its dependency libraries.
+link_all_deplibs=$link_all_deplibs
+
+# Set to "yes" if exported symbols are required.
+always_export_symbols=$always_export_symbols
+
+# The commands to list exported symbols.
+export_symbols_cmds=$lt_export_symbols_cmds
+
+# Symbols that should not be listed in the preloaded symbols.
+exclude_expsyms=$lt_exclude_expsyms
+
+# Symbols that must always be exported.
+include_expsyms=$lt_include_expsyms
+
+# Commands necessary for linking programs (against libraries) with templates.
+prelink_cmds=$lt_prelink_cmds
+
+# Commands necessary for finishing linking programs.
+postlink_cmds=$lt_postlink_cmds
+
+# Specify filename containing input files.
+file_list_spec=$lt_file_list_spec
+
+# How to hardcode a shared library path into an executable.
+hardcode_action=$hardcode_action
+
+# ### END LIBTOOL CONFIG
+
+_LT_EOF
+
+    cat <<'_LT_EOF' >> "$cfgfile"
+
+# ### BEGIN FUNCTIONS SHARED WITH CONFIGURE
+
+# func_munge_path_list VARIABLE PATH
+# -----------------------------------
+# VARIABLE is name of variable containing _space_ separated list of
+# directories to be munged by the contents of PATH, which is string
+# having a format:
+# "DIR[:DIR]:"
+#       string "DIR[ DIR]" will be prepended to VARIABLE
+# ":DIR[:DIR]"
+#       string "DIR[ DIR]" will be appended to VARIABLE
+# "DIRP[:DIRP]::[DIRA:]DIRA"
+#       string "DIRP[ DIRP]" will be prepended to VARIABLE and string
+#       "DIRA[ DIRA]" will be appended to VARIABLE
+# "DIR[:DIR]"
+#       VARIABLE will be replaced by "DIR[ DIR]"
+func_munge_path_list ()
+{
+    case x$2 in
+    x)
+        ;;
+    *:)
+        eval $1=\"`$ECHO $2 | $SED 's/:/ /g'` \$$1\"
+        ;;
+    x:*)
+        eval $1=\"\$$1 `$ECHO $2 | $SED 's/:/ /g'`\"
+        ;;
+    *::*)
+        eval $1=\"\$$1\ `$ECHO $2 | $SED -e 's/.*:://' -e 's/:/ /g'`\"
+        eval $1=\"`$ECHO $2 | $SED -e 's/::.*//' -e 's/:/ /g'`\ \$$1\"
+        ;;
+    *)
+        eval $1=\"`$ECHO $2 | $SED 's/:/ /g'`\"
+        ;;
+    esac
+}
+
+
+# Calculate cc_basename.  Skip known compiler wrappers and cross-prefix.
+func_cc_basename ()
+{
+    for cc_temp in $*""; do
+      case $cc_temp in
+        compile | *[\\/]compile | ccache | *[\\/]ccache ) ;;
+        distcc | *[\\/]distcc | purify | *[\\/]purify ) ;;
+        \-*) ;;
+        *) break;;
+      esac
+    done
+    func_cc_basename_result=`$ECHO "$cc_temp" | $SED "s%.*/%%; s%^$host_alias-%%"`
+}
+
+
+# ### END FUNCTIONS SHARED WITH CONFIGURE
+
+_LT_EOF
+
+  case $host_os in
+  aix3*)
+    cat <<\_LT_EOF >> "$cfgfile"
+# AIX sometimes has problems with the GCC collect2 program.  For some
+# reason, if we set the COLLECT_NAMES environment variable, the problems
+# vanish in a puff of smoke.
+if test set != "${COLLECT_NAMES+set}"; then
+  COLLECT_NAMES=
+  export COLLECT_NAMES
+fi
+_LT_EOF
+    ;;
+  esac
+
+
+
+ltmain=$ac_aux_dir/ltmain.sh
+
+
+  # We use sed instead of cat because bash on DJGPP gets confused if
+  # if finds mixed CR/LF and LF-only lines.  Since sed operates in
+  # text mode, it properly converts lines to CR/LF.  This bash problem
+  # is reportedly fixed, but why not run on old versions too?
+  $SED '$q' "$ltmain" >> "$cfgfile" \
+     || (rm -f "$cfgfile"; exit 1)
+
+   mv -f "$cfgfile" "$ofile" ||
+    (rm -f "$ofile" && cp "$cfgfile" "$ofile" && rm -f "$cfgfile")
+  chmod +x "$ofile"
+
+ ;;
+    "libpng-config":F) chmod +x libpng-config ;;
+
+  esac
+done # for ac_tag
+
+
+as_fn_exit 0
+_ACEOF
+ac_clean_files=$ac_clean_files_save
+
+test $ac_write_fail = 0 ||
+  as_fn_error $? "write failure creating $CONFIG_STATUS" "$LINENO" 5
+
+
+# configure is writing to config.log, and then calls config.status.
+# config.status does its own redirection, appending to config.log.
+# Unfortunately, on DOS this fails, as config.log is still kept open
+# by configure, so config.status won't be able to write to it; its
+# output is simply discarded.  So we exec the FD to /dev/null,
+# effectively closing config.log, so it can be properly (re)opened and
+# appended to by config.status.  When coming back to configure, we
+# need to make the FD available again.
+if test "$no_create" != yes; then
+  ac_cs_success=:
+  ac_config_status_args=
+  test "$silent" = yes &&
+    ac_config_status_args="$ac_config_status_args --quiet"
+  exec 5>/dev/null
+  $SHELL $CONFIG_STATUS $ac_config_status_args || ac_cs_success=false
+  exec 5>>config.log
+  # Use ||, not &&, to avoid exiting from the if with $? = 1, which
+  # would make configure fail if this is the last instruction.
+  $ac_cs_success || as_fn_exit 1
+fi
+if test -n "$ac_unrecognized_opts" && test "$enable_option_checking" != no; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: unrecognized options: $ac_unrecognized_opts" >&5
+printf "%s\n" "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2;}
+fi
+
+
Index: /trunk/src/libs/libpng-1.6.45/configure.ac
===================================================================
--- /trunk/src/libs/libpng-1.6.45/configure.ac	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/configure.ac	(revision 107811)
@@ -0,0 +1,671 @@
+# configure.ac
+
+# Copyright (c) 2018-2024 Cosmin Truta
+# Copyright (c) 2004-2016 Glenn Randers-Pehrson
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+dnl Process this file with autoconf to produce a configure script.
+dnl
+dnl Minor upgrades (compatible ABI): increment the package version
+dnl (third field in two places below) and set the PNGLIB_RELEASE
+dnl variable.
+dnl
+dnl Major upgrades (incompatible ABI): increment the package major
+dnl version (second field, or first if desired), set the minor
+dnl to 0, set PNGLIB_MAJOR below *and* follow the instructions in
+dnl Makefile.am to upgrade the package name.
+
+dnl This is here to prevent earlier autoconf from being used, it
+dnl should not be necessary to regenerate configure if the time
+dnl stamps are correct
+AC_PREREQ([2.68])
+
+dnl Version number stuff here:
+
+AC_INIT([libpng],[1.6.43],[png-mng-implement@lists.sourceforge.net])
+AC_CONFIG_MACRO_DIR([scripts/autoconf])
+
+# libpng does not follow GNU file name conventions (hence 'foreign')
+# color-tests requires automake 1.11 or later
+# silent-rules requires automake 1.11 or later
+# dist-xz requires automake 1.11 or later
+# 1.12.2 fixes a security issue in 1.11.2 and 1.12.1
+# 1.13 is required for parallel tests
+AM_INIT_AUTOMAKE([1.13 foreign dist-xz color-tests silent-rules subdir-objects])
+# The following line causes --disable-maintainer-mode to be the default to
+# configure. This is necessary because libpng distributions cannot rely on the
+# time stamps of the autotools generated files being correct
+AM_MAINTAINER_MODE
+
+dnl configure.ac and Makefile.am expect automake 1.11.2 or a compatible later
+dnl version; aclocal.m4 will generate a failure if you use a prior version of
+dnl automake, so the following is not necessary (and is not defined anyway):
+dnl AM_PREREQ([1.11.2])
+dnl stop configure from automagically running automake
+
+PNGLIB_VERSION=1.6.43
+PNGLIB_MAJOR=1
+PNGLIB_MINOR=6
+PNGLIB_RELEASE=43
+
+dnl End of version number stuff
+
+AC_CONFIG_SRCDIR([pngget.c])
+AC_CONFIG_HEADERS([config.h])
+
+# Check for basic programs.
+AC_LANG([C])
+AC_PROG_CC
+AM_PROG_AS
+LT_PATH_LD
+AC_PROG_CPP
+AC_PROG_AWK
+AC_PROG_INSTALL
+AC_PROG_LN_S
+AC_PROG_MAKE_SET
+
+dnl libtool/libtoolize; version 2.4.2 is the tested version. This or any
+dnl compatible later version may be used
+LT_INIT([win32-dll])
+LT_PREREQ([2.4.2])
+
+dnl Declare the AWK variable.
+AC_ARG_VAR(AWK, [AWK language processor])
+
+# Some awk implementations crash when confronted with pnglibconf.dfa.
+# Run a test now, to make sure this doesn't happen.
+AC_MSG_CHECKING([if awk ($AWK) works])
+if ${AWK} -f ${srcdir}/scripts/options.awk out="/dev/null" version=search\
+   ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+   ${srcdir}/pngusr.dfa 1>&2
+then
+   AC_MSG_RESULT([yes])
+else
+   AC_MSG_FAILURE([no], 1)
+fi
+
+# This is a remnant of the old cc -E validation, where it may have been
+# necessary to use a different preprocessor for .dfn files
+DFNCPP="$CPP"
+AC_SUBST(DFNCPP)
+
+AC_ARG_ENABLE([tests],
+   AS_HELP_STRING([--disable-tests],
+      [do not build the test programs (default is to build)]),
+      [enable_tests="$enableval"],
+      [enable_tests=yes])
+
+AM_CONDITIONAL([ENABLE_TESTS],
+   [test "$enable_tests" != "no"])
+
+AC_ARG_ENABLE([tools],
+   AS_HELP_STRING([--disable-tools],
+      [do not build the auxiliary tools (default is to build)]),
+      [enable_tools="$enableval"],
+      [enable_tools=yes])
+
+AM_CONDITIONAL([ENABLE_TOOLS],
+   [test "$enable_tools" != "no"])
+
+# -Werror cannot be passed to GCC in CFLAGS because configure will fail
+# (it checks the compiler with a program that generates a warning).
+# Add the following option to deal with this:
+AC_ARG_VAR(PNG_COPTS,
+   [additional flags for the C compiler, to be used for options that would]
+   [cause configure itself to fail])
+AC_ARG_ENABLE(werror,
+   AS_HELP_STRING([[[--enable-werror[=OPT]]]],
+      [Pass -Werror or the given argument to the compiler if it is supported]),
+   [test "$enable_werror" = "yes" && enable_werror="-Werror"
+    if test "$enable_werror" != "no"; then
+      sav_CFLAGS="$CFLAGS"
+      CFLAGS="$enable_werror $CFLAGS"
+      AC_MSG_CHECKING([if the compiler allows $enable_werror])
+      AC_COMPILE_IFELSE(
+         [AC_LANG_SOURCE([
+            [int main(int argc, char **argv){]
+            [return argv[argc-1][0];]
+            [}]])],
+         AC_MSG_RESULT(yes)
+         PNG_COPTS="$PNG_COPTS $enable_werror",
+         AC_MSG_RESULT(no))
+      CFLAGS="$sav_CFLAGS"
+    fi],)
+
+# For GCC 5 the default mode for C is -std=gnu11 instead of -std=gnu89.
+# In pngpriv.h we request just the POSIX 1003.1 and C89 APIs by defining
+# _POSIX_SOURCE to 1. This is incompatible with the new default mode, so
+# we test for that and force the "-std=c89" compiler option:
+AC_MSG_CHECKING([if we need to force back C standard to C89])
+AC_COMPILE_IFELSE(
+   [AC_LANG_PROGRAM([
+      [#define _POSIX_SOURCE 1]
+      [#include <stdio.h>]
+   ])],
+   AC_MSG_RESULT(no),[
+      if test "x$GCC" != "xyes"; then
+         AC_MSG_ERROR(
+            [Forcing back to C89 is required but the flags are only known for GCC])
+      fi
+   AC_MSG_RESULT(yes)
+   CFLAGS="$CFLAGS -std=c89"
+])
+
+# Checks for structures and compiler characteristics.
+AC_STRUCT_TM
+AC_C_RESTRICT
+
+# Checks for library functions.
+AC_CHECK_FUNCS([pow], ,
+  [AC_CHECK_LIB([m], [pow], , [AC_MSG_ERROR([cannot find pow])])])
+
+# Some later POSIX 1003.1 functions are required for test programs, failure
+# here is soft (the corresponding test program is not built).
+AC_CHECK_FUNC([clock_gettime], , [AC_MSG_WARN([not building timepng])])
+AM_CONDITIONAL([HAVE_CLOCK_GETTIME], [test "$ac_cv_func_clock_gettime" = "yes"])
+
+AC_ARG_WITH(zlib-prefix,
+   AS_HELP_STRING([[[--with-zlib-prefix]]],
+      [prefix that may have been used in installed zlib]),
+      [ZPREFIX=${withval}],
+      [ZPREFIX='z_'])
+AC_CHECK_LIB([z], [zlibVersion], ,
+  [AC_CHECK_LIB([z], [${ZPREFIX}zlibVersion], ,
+     [AC_MSG_ERROR([zlib not installed])])])
+
+# The following is for pngvalid, to ensure it catches FP errors even on
+# platforms that don't enable FP exceptions, the function appears in the math
+# library (typically), it's not an error if it is not found.
+AC_CHECK_LIB([m], [feenableexcept])
+AC_CHECK_FUNCS([feenableexcept])
+
+AC_MSG_CHECKING([if using Solaris linker])
+SLD=`$LD --version 2>&1 | grep Solaris`
+if test "$SLD"; then
+    have_solaris_ld=yes
+    AC_MSG_RESULT(yes)
+else
+    have_solaris_ld=no
+    AC_MSG_RESULT(no)
+fi
+AM_CONDITIONAL(HAVE_SOLARIS_LD, test "$have_solaris_ld" = "yes")
+
+AC_MSG_CHECKING([if libraries can be versioned])
+# Special case for PE/COFF platforms: ld reports
+# support for version-script, but doesn't actually
+# DO anything with it.
+case $host in
+*cygwin* | *mingw32* | *interix* )
+    have_ld_version_script=no
+    AC_MSG_RESULT(no)
+;;
+* )
+
+if test "$have_solaris_ld" = "yes"; then
+    GLD=`$LD --help < /dev/null 2>&1 | grep 'M mapfile'`
+else
+    GLD=`$LD --help < /dev/null 2>/dev/null | grep version-script`
+fi
+
+if test "$GLD"; then
+    have_ld_version_script=yes
+    AC_MSG_RESULT(yes)
+else
+    have_ld_version_script=no
+    AC_MSG_RESULT(no)
+    AC_MSG_WARN(*** You have not enabled versioned symbols.)
+fi
+;;
+esac
+
+AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
+
+if test "$have_ld_version_script" = "yes"; then
+    AC_MSG_CHECKING([for symbol prefix])
+    SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
+                  | ${CPP:-${CC:-gcc} -E} - 2>&1 \
+                  | ${EGREP:-grep} "^PREFIX=" \
+                  | ${SED:-sed} -e "s:^PREFIX=::" -e "s:__USER_LABEL_PREFIX__::"`
+    AC_SUBST(SYMBOL_PREFIX)
+    AC_MSG_RESULT($SYMBOL_PREFIX)
+fi
+
+# Substitutions for .in files
+AC_SUBST(PNGLIB_VERSION)
+AC_SUBST(PNGLIB_MAJOR)
+AC_SUBST(PNGLIB_MINOR)
+AC_SUBST(PNGLIB_RELEASE)
+
+# Additional arguments (and substitutions)
+# Allow the pkg-config directory to be set
+AC_ARG_WITH(pkgconfigdir,
+   AS_HELP_STRING([[[--with-pkgconfigdir]]],
+      [Use the specified pkgconfig dir (default is libdir/pkgconfig)]),
+   [pkgconfigdir=${withval}],
+   [pkgconfigdir='${libdir}/pkgconfig'])
+
+AC_SUBST([pkgconfigdir])
+AC_MSG_NOTICE([[pkgconfig directory is ${pkgconfigdir}]])
+
+# Make the *-config binary config scripts optional
+AC_ARG_WITH(binconfigs,
+   AS_HELP_STRING([[[--with-binconfigs]]],
+      [Generate shell libpng-config scripts as well as pkg-config data]
+      [@<:@default=yes@:>@]),
+   [if test "${withval}" = no; then
+      binconfigs=
+      AC_MSG_NOTICE([[libpng-config scripts will not be built]])
+    else
+      binconfigs='${binconfigs}'
+    fi],
+   [binconfigs='${binconfigs}'])
+AC_SUBST([binconfigs])
+
+# Support for prefixes to the API function names; this will generate defines
+# at the start of the build to rename exported library functions
+AC_ARG_WITH(libpng-prefix,
+   AS_HELP_STRING([[[--with-libpng-prefix]]],
+      [prefix libpng exported function (API) names with the given value]),
+   [if test "${withval:-no}" != "no"; then
+      AC_SUBST([PNG_PREFIX], [${withval}])
+    fi])
+AM_CONDITIONAL([DO_PNG_PREFIX], [test "${with_libpng_prefix:-no}" != "no"])
+
+# Control over what links are made for installed files.  Versioned files are
+# always installed, when the following options are turned on corresponding
+# unversioned links are also created (normally as symbolic links):
+AC_ARG_ENABLE([unversioned-links],
+   AS_HELP_STRING([[[--enable-unversioned-links]]],
+      [Installed libpng header files are placed in a versioned subdirectory]
+      [and installed libpng library (including DLL) files are versioned.]
+      [If this option is enabled unversioned links will be created pointing to]
+      [the corresponding installed files.  If you use libpng.pc or]
+      [libpng-config for all builds you do not need these links, but if you]
+      [compile programs directly they will typically #include <png.h> and]
+      [link with -lpng; in that case you need the links.]
+      [The links can be installed manually using 'make install-header-links']
+      [and 'make install-library-links' and can be removed using the]
+      [corresponding uninstall- targets.  If you do enable this option every]
+      [libpng 'make install' will recreate the links to point to the just]
+      [installed version of libpng.  The default is to create the links;]
+      [use --disable-unversioned-links to change this]))
+
+# The AM_CONDITIONAL test is written so that the default is enabled;
+# --disable-unversioned-links must be given to turn the option off.
+AM_CONDITIONAL([DO_INSTALL_LINKS],[test "$enable_unversioned_links" != "no"])
+
+AC_ARG_ENABLE([unversioned-libpng-pc],
+   AS_HELP_STRING([[[--enable-unversioned-libpng-pc]]],
+      [Install the configuration file 'libpng.pc' as a link to the versioned]
+      [version.  This is done by default - use --disable-unversioned-libpng-pc]
+      [to change this.]))
+AM_CONDITIONAL([DO_INSTALL_LIBPNG_PC],
+   [test "$enable_unversioned_libpng_pc" != "no"])
+
+AC_ARG_ENABLE([unversioned-libpng-config],
+   AS_HELP_STRING([[[--enable-unversioned-libpng-config]]],
+      [Install the configuration file 'libpng-config' as a link to the]
+      [versioned version.  This is done by default - use]
+      [--disable-unversioned-libpng-config to change this.]))
+AM_CONDITIONAL([DO_INSTALL_LIBPNG_CONFIG],
+   [test "$enable_unversioned_libpng_config" != "no"])
+
+# HOST-SPECIFIC OPTIONS
+# =====================
+#
+# DEFAULT
+# =======
+#
+AC_ARG_ENABLE([hardware-optimizations],
+   AS_HELP_STRING([[[--enable-hardware-optimizations]]],
+      [Enable hardware optimizations: =no/off, yes/on.]),
+   [case "$enableval" in
+      no|off)
+         # disable hardware optimization on all systems:
+         enable_arm_neon=no
+         AC_DEFINE([PNG_ARM_NEON_OPT], [0],
+           [Disable ARM_NEON optimizations])
+         enable_mips_msa=no
+         AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
+           [Disable MIPS_MSA optimizations])
+         enable_mips_mmi=no
+         AC_DEFINE([PNG_MIPS_MMI_OPT], [0],
+           [Disable MIPS_MMI optimizations])
+         enable_powerpc_vsx=no
+         AC_DEFINE([PNG_POWERPC_VSX_OPT], [0],
+           [Disable POWERPC VSX optimizations])
+         enable_intel_sse=no
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [0],
+           [Disable INTEL_SSE optimizations])
+         enable_loongarch_lsx=no
+         AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [0],
+           [Disable LOONGARCH_LSX optimizations])
+         ;;
+      *)
+         # allow enabling hardware optimization on any system:
+         case "$host_cpu" in
+            arm*|aarch64*)
+              enable_arm_neon=yes
+              AC_DEFINE([PNG_ARM_NEON_OPT], [2],
+                [Enable ARM_NEON optimizations])
+              ;;
+            mipsel*|mips64el*)
+              enable_mips_mmi=yes
+              enable_mips_msa=yes
+              AC_DEFINE([PNG_MIPS_MMI_OPT], [1],
+                [Enable MIPS_MMI optimizations])
+              AC_DEFINE([PNG_MIPS_MSA_OPT], [2],
+                [Enable MIPS_MSA optimizations])
+              ;;
+            i?86|x86_64)
+              enable_intel_sse=yes
+              AC_DEFINE([PNG_INTEL_SSE_OPT], [1],
+                [Enable Intel SSE optimizations])
+              ;;
+            powerpc*|ppc64*)
+              enable_powerpc_vsx=yes
+              AC_DEFINE([PNG_POWERPC_VSX_OPT], [2],
+                [Enable POWERPC VSX optimizations])
+              ;;
+            loongarch*)
+              enable_loongarch_lsx=yes
+              AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [1],
+                [Enable LOONGARCH_LSX optimizations])
+              ;;
+         esac
+         ;;
+   esac])
+
+# ARM NEON
+# ========
+
+AC_ARG_ENABLE([arm-neon],
+   AS_HELP_STRING([[[--enable-arm-neon]]],
+      [Enable ARM NEON optimizations: =no/off, check, api, yes/on.]
+      [no/off: disable the optimizations;]
+      [check: use internal checking code (deprecated and poorly supported);]
+      [api: disable by default, enable by a call to png_set_option;]
+      [yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __ARM_NEON__ systems:
+         AC_DEFINE([PNG_ARM_NEON_OPT], [0],
+                   [Disable ARM Neon optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_arm_neon=no ;;
+      check)
+         AC_DEFINE([PNG_ARM_NEON_CHECK_SUPPORTED], [],
+                   [Check for ARM Neon support at run-time]);;
+      api)
+         AC_DEFINE([PNG_ARM_NEON_API_SUPPORTED], [],
+                   [Turn on ARM Neon optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_ARM_NEON_OPT], [2],
+                   [Enable ARM Neon optimizations])
+         AC_MSG_WARN([--enable-arm-neon: please specify 'check' or 'api';]
+            [if you want the optimizations unconditionally,]
+            [pass '-mfpu=neon' to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-arm-neon=${enable_arm_neon}:]
+                      [invalid argument])
+   esac])
+
+# Add ARM-specific files to all builds where $host_cpu is arm ('arm*') or
+# where ARM optimizations were explicitly requested. (This allows a fallback
+# if a future host CPU does not match 'arm*'.)
+
+AM_CONDITIONAL([PNG_ARM_NEON],
+   [test "$enable_arm_neon" != 'no' &&
+    case "$host_cpu" in
+      arm*|aarch64*) : ;;
+      *)    test "$enable_arm_neon" != '' ;;
+    esac])
+
+# MIPS MSA
+# ========
+
+AC_ARG_ENABLE([mips-msa],
+   AS_HELP_STRING([[[--enable-mips-msa]]],
+      [Enable MIPS MSA optimizations: =no/off, check, api, yes/on.]
+      [no/off: disable the optimizations;]
+      [check: use internal checking code (deprecated and poorly supported);]
+      [api: disable by default, enable by a call to png_set_option;]
+      [yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __mips_msa systems:
+         AC_DEFINE([PNG_MIPS_MSA_OPT], [0],
+                   [Disable MIPS MSA optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_mips_msa=no ;;
+      check)
+         AC_DEFINE([PNG_MIPS_MSA_CHECK_SUPPORTED], [],
+                   [Check for MIPS MSA support at run-time]);;
+      api)
+         AC_DEFINE([PNG_MIPS_MSA_API_SUPPORTED], [],
+                   [Turn on MIPS MSA optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_MIPS_MSA_OPT], [2],
+                   [Enable MIPS MSA optimizations])
+         AC_MSG_WARN([--enable-mips-msa: please specify 'check' or 'api';]
+            [if you want the optimizations unconditionally,]
+            [pass '-mmsa -mfp64' to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-mips-msa=${enable_mips_msa}:]
+                      [invalid argument])
+   esac])
+
+# Add MIPS-specific files to all builds where $host_cpu is mips ('mips*') or
+# where MIPS optimizations were explicitly requested. (This allows a fallback
+# if a future host CPU does not match 'mips*'.)
+
+AM_CONDITIONAL([PNG_MIPS_MSA],
+   [test "$enable_mips_msa" != 'no' &&
+    case "$host_cpu" in
+      mipsel*|mips64el*) : ;;
+    esac])
+
+# MIPS MMI
+# ========
+
+AC_ARG_ENABLE([mips-mmi],
+   AS_HELP_STRING([[[--enable-mips-mmi]]],
+      [Enable MIPS MMI optimizations: =no/off, check, api, yes/on.]
+      [no/off: disable the optimizations;]
+      [check: use internal checking code (deprecated and poorly supported);]
+      [api: disable by default, enable by a call to png_set_option;]
+      [yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __mips_mmi systems:
+         AC_DEFINE([PNG_MIPS_MMI_OPT], [0],
+                   [Disable MIPS MMI optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_mips_mmi=no;;
+      check)
+         AC_DEFINE([PNG_MIPS_MMI_CHECK_SUPPORTED], [],
+                   [Check for MIPS MMI support at run-time]);;
+      api)
+         AC_DEFINE([PNG_MIPS_MMI_API_SUPPORTED], [],
+                   [Turn on MIPS MMI optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_MIPS_MMI_OPT], [1],
+                   [Enable MIPS MMI optimizations])
+         AC_MSG_WARN([--enable-mips-mmi: please specify 'check' or 'api';]
+            [if you want the optimizations unconditionally]
+            [pass '-mloongson-mmi -march=loongson3a' to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-mips-mmi=${enable_mips_mmi}:]
+                      [invalid argument])
+   esac])
+
+# Add MIPS specific files to all builds where the host_cpu is mips ('mips*') or
+# where MIPS optimizations were explicitly requested. (This allows a fallback
+# if a future host CPU does not match 'mips*'.)
+
+AM_CONDITIONAL([PNG_MIPS_MMI],
+   [test "$enable_mips_mmi" != 'no' &&
+    case "$host_cpu" in
+      mipsel*|mips64el*) : ;;
+    esac])
+
+# INTEL SSE
+# =========
+
+AC_ARG_ENABLE([intel-sse],
+   AS_HELP_STRING([[[--enable-intel-sse]]],
+      [Enable Intel SSE optimizations: =no/off, yes/on.]
+      [no/off: disable the optimizations;]
+      [yes/on: enable the optimizations.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling:
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [0],
+                   [Disable Intel SSE optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_intel_sse=no ;;
+      yes|on)
+         AC_DEFINE([PNG_INTEL_SSE_OPT], [1],
+                   [Enable Intel SSE optimizations]);;
+      *)
+         AC_MSG_ERROR([--enable-intel-sse=${enable_intel_sse}:]
+                      [invalid argument])
+   esac])
+
+# Add Intel-specific files to all builds where $host_cpu is Intel ('x86*') or
+# where Intel optimizations were explicitly requested. (This allows a fallback
+# if a future host CPU does not match 'x86*'.)
+AM_CONDITIONAL([PNG_INTEL_SSE],
+   [test "$enable_intel_sse" != 'no' &&
+    case "$host_cpu" in
+      i?86|x86_64) : ;;
+      *)    test "$enable_intel_sse" != '' ;;
+    esac])
+
+# POWERPC VSX
+# ===========
+
+AC_ARG_ENABLE([powerpc-vsx],
+AS_HELP_STRING([[[--enable-powerpc-vsx]]],
+      [Enable POWERPC VSX optimizations: =no/off, check, api, yes/on.]
+      [no/off: disable the optimizations;]
+      [check: use internal checking code;]
+      [api: disable by default, enable by a call to png_set_option;]
+      [yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __ppc64__ systems:
+         AC_DEFINE([PNG_POWERPC_VSX_OPT], [0],
+                   [Disable POWERPC VSX optimizations])
+         # Prevent inclusion of the platform-specific files below:
+         enable_powerpc_vsx=no ;;
+      check)
+         AC_DEFINE([PNG_POWERPC_VSX_CHECK_SUPPORTED], [],
+                   [Check for POWERPC VSX support at run-time])
+         AC_MSG_WARN([--enable-powerpc-vsx: please see contrib/powerpc/README]
+                     [for the list of supported systems.]);;
+      api)
+         AC_DEFINE([PNG_POWERPC_VSX_API_SUPPORTED], [],
+                   [Turn on POWERPC VSX optimizations at run-time]);;
+      yes|on)
+         AC_DEFINE([PNG_POWERPC_VSX_OPT], [2],
+                   [Enable POWERPC VSX optimizations])
+         AC_MSG_WARN([--enable-powerpc-vsx: please specify 'check' or 'api';]
+            [if you want the optimizations unconditionally,]
+            [pass '-maltivec -mvsx' or '-mcpu=power8' to the compiler.]);;
+      *)
+         AC_MSG_ERROR([--enable-powerpc-vsx=${enable_powerpc_vsx}:]
+                      [invalid argument])
+   esac])
+
+# Add PowerPC-specific files to all builds where $host_cpu is powerpc
+# ('powerpc*') or where PowerPC optimizations were explicitly requested.
+# (This allows a fallback if a future host CPU does not match 'powerpc*'.)
+
+AM_CONDITIONAL([PNG_POWERPC_VSX],
+   [test "$enable_powerpc_vsx" != 'no' &&
+    case "$host_cpu" in
+      powerpc*|ppc64*) : ;;
+    esac])
+
+# LOONGARCH LSX
+# =============
+
+AC_ARG_ENABLE([loongarch-lsx],
+   AS_HELP_STRING([[[--enable-loongarch-lsx]]],
+      [Enable LOONGARCH LSX optimizations: =no/off, yes/on:]
+      [no/off: disable the optimizations;]
+      [yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
+   [case "$enableval" in
+      no|off)
+         # disable the default enabling on __loongarch_simd systems:
+         AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [0],
+                   [Disable LOONGARCH LSX optimizations])
+         # Prevent inclusion of the assembler files below:
+         enable_loongarch_lsx=no;;
+      yes|on)
+         AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [1],
+                   [Enable LOONGARCH LSX optimizations])
+         ;;
+      *)
+         AC_MSG_ERROR([--enable-loongarch-lsx=${enable_loongarch_lsx}:]
+                      [invalid argument])
+   esac])
+
+if test "$enable_loongarch_lsx" != "no" &&
+   case "$host_cpu" in
+      loongarch*) : ;;
+      *)    test "$enable_loongarch_lsx" != '' ;;
+   esac
+then
+   compiler_support_loongarch_lsx=no
+   AC_MSG_CHECKING(whether to use LoongArch LSX intrinsics)
+   save_CFLAGS="$CFLAGS"
+   LSX_CFLAGS="${LSX_CFLAGS:-"-mlsx"}"
+   CFLAGS="$CFLAGS $LSX_CFLAGS"
+   AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+#include <lsxintrin.h>
+int main(){
+   __m128i a, b, c;
+   a = __lsx_vadd_w(b, c);
+   return 0;
+}]])],compiler_support_loongarch_lsx=yes)
+   CFLAGS="$save_CFLAGS"
+   AC_MSG_RESULT($compiler_support_loongarch_lsx)
+   if test "$compiler_support_loongarch_lsx" = "yes"; then
+      AC_DEFINE([PNG_LOONGARCH_LSX_OPT], [1],
+                [Enable LOONGARCH LSX optimizations])
+   else
+      AC_MSG_WARN([Compiler does not support loongarch LSX.])
+   fi
+fi
+
+# Add LoongArch specific files to all builds where the host_cpu is loongarch
+# ('loongarch*') or where LoongArch optimizations were explicitly requested.
+# (This allows a fallback if a future host CPU does not match 'loongarch*'.)
+
+AM_CONDITIONAL([PNG_LOONGARCH_LSX],
+   [test "$enable_loongarch_lsx" != "no" &&
+    test "$compiler_support_loongarch_lsx" = "yes" &&
+    case "$host_cpu" in
+      loongarch*) : ;;
+      *)    test "$enable_loongarch_lsx" != '' ;;
+    esac])
+
+AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])
+
+# Config files, substituting as above
+AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])
+AC_CONFIG_FILES([libpng-config:libpng-config.in],
+   [chmod +x libpng-config])
+
+AC_OUTPUT
Index: /trunk/src/libs/libpng-1.6.45/contrib/README.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/README.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/README.txt	(revision 107811)
@@ -0,0 +1,5 @@
+
+This "contrib" directory contains contributions which are not necessarily under
+the libpng license, although all are open source.  They are not part of
+libpng proper and are not used for building the library, although some are used
+for testing the library via "make check".
Index: /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/README	(revision 107811)
@@ -0,0 +1,83 @@
+OPERATING SYSTEM SPECIFIC ARM NEON DETECTION
+--------------------------------------------
+
+Detection of the ability to execute ARM NEON on an ARM processor requires
+operating system support.  (The information is not available in user mode.)
+
+HOW TO USE THIS
+---------------
+
+This directory contains C code fragments that can be included in arm/arm_init.c
+by setting the macro PNG_ARM_NEON_FILE to the file name in "" or <> at build
+time.  This setting is not recorded in pnglibconf.h and can be changed simply by
+rebuilding arm/arm_init.o with the required macro definition.
+
+For any of this code to be used the ARM NEON code must be enabled and run time
+checks must be supported.  I.e.:
+
+#if PNG_ARM_NEON_OPT > 0
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-arm-neon=check
+
+Apart from the basic Linux implementation in contrib/arm-neon/linux.c this code
+is unsupported.  That means that it is not even compiled on a regular basis and
+may be broken in any given minor release.
+
+FILE FORMAT
+-----------
+
+Each file documents its testing status as of the last time it was tested (which
+may have been a long time ago):
+
+STATUS: one of:
+   SUPPORTED: This indicates that the file is included in the regularly
+         performed test builds and bugs are fixed when discovered.
+   COMPILED: This indicates that the code did compile at least once.  See the
+         more detailed description for the extent to which the result was
+         successful.
+   TESTED: This means the code was fully compiled into the libpng test programs
+         and these were run at least once.
+
+BUG REPORTS: an email address to which to send reports of problems
+
+The file is a fragment of C code. It should not define any 'extern' symbols;
+everything should be static.  It must define the function:
+
+static int png_have_neon(png_structp png_ptr);
+
+That function must return 1 if ARM NEON instructions are supported, 0 if not.
+It must not execute png_error unless it detects a bug.  A png_error will prevent
+the reading of the PNG and in the future, writing too.
+
+BUG REPORTS
+-----------
+
+If you mail a bug report for any file that is not SUPPORTED there may only be
+limited response.  Consider fixing it and sending a patch to fix the problem -
+this is more likely to result in action.
+
+CONTRIBUTIONS
+-------------
+
+You may send contributions of new implementations to
+png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+possible.  Obviously OS dependencies are to be expected.  If you submit code you
+must have the authors permission and it must have a license that is acceptable
+to the current maintainer; in particular that license must permit modification
+and redistribution.
+
+Please try to make the contribution a single file and give the file a clear and
+unambiguous name that identifies the target OS.  If multiple files really are
+required put them all in a sub-directory.
+
+You must also be prepared to handle bug reports from users of the code, either
+by joining the png-mng-implement mailing list or by providing an email for the
+"BUG REPORTS" entry or both.  Please make sure that the header of the file
+contains the STATUS and BUG REPORTS fields as above.
+
+Please list the OS requirements as precisely as possible.  Ideally you should
+also list the environment in which the code has been tested and certainly list
+any environments where you suspect it might not work.
Index: /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/android-ndk.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/android-ndk.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/android-ndk.c	(revision 107811)
@@ -0,0 +1,39 @@
+/* contrib/arm-neon/android-ndk.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by John Bowler, 2014.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: COMPILED, UNTESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for the Android NDK, see:
+ *
+ * Documentation:
+ *    http://www.kandroid.org/ndk/docs/CPU-ARM-NEON.html
+ *    https://code.google.com/p/android/issues/detail?id=49065
+ *
+ * NOTE: this requires that libpng is built against the Android NDK and linked
+ * with an implementation of the Android ARM 'cpu-features' library.  The code
+ * has been compiled only, not linked: no version of the library has been found,
+ * only the header files exist in the NDK.
+ */
+
+#include <cpu-features.h>
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   /* This is a whole lot easier than the linux code, however it is probably
+    * implemented as below, therefore it is better to cache the result (these
+    * function calls may be slow!)
+    */
+   PNG_UNUSED(png_ptr)
+   return android_getCpuFamily() == ANDROID_CPU_FAMILY_ARM &&
+      (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) != 0;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/linux-auxv.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/linux-auxv.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/linux-auxv.c	(revision 107811)
@@ -0,0 +1,120 @@
+/* contrib/arm-neon/linux-auxv.c
+ *
+ * Copyright (c) 2014 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: COMPILED, TESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for Linux versions which allow access to
+ * /proc/self/auxv.  This is probably faster, cleaner and safer than the code to
+ * read /proc/cpuinfo in contrib/arm-neon/linux, however it is yet another piece
+ * of potentially untested code and has more complex dependencies than the code
+ * to read cpuinfo.
+ *
+ * This generic __linux__ implementation requires reading /proc/self/auxv and
+ * looking at each element for one that records NEON capabilities.
+ */
+
+#include <unistd.h> /* for POSIX 1003.1 */
+#include <errno.h>  /* for EINTR */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <elf.h>
+#include <asm/hwcap.h>
+
+/* A read call may be interrupted, in which case it returns -1 and sets errno to
+ * EINTR if nothing was done, otherwise (if something was done) a partial read
+ * may result.
+ */
+static size_t
+safe_read(png_structp png_ptr, int fd, void *buffer_in, size_t nbytes)
+{
+   size_t ntotal = 0;
+   char *buffer = png_voidcast(char*, buffer_in);
+
+   while (nbytes > 0)
+   {
+      unsigned int nread;
+      int iread;
+
+      /* Passing nread > INT_MAX to read is implementation defined in POSIX
+       * 1003.1, therefore despite the unsigned argument portable code must
+       * limit the value to INT_MAX!
+       */
+      if (nbytes > INT_MAX)
+         nread = INT_MAX;
+
+      else
+         nread = (unsigned int)/*SAFE*/nbytes;
+
+      iread = read(fd, buffer, nread);
+
+      if (iread == -1)
+      {
+         /* This is the devil in the details, a read can terminate early with 0
+          * bytes read because of EINTR, yet it still returns -1 otherwise end
+          * of file cannot be distinguished.
+          */
+         if (errno != EINTR)
+         {
+            png_warning(png_ptr, "/proc read failed");
+            return 0; /* I.e., a permanent failure */
+         }
+      }
+
+      else if (iread < 0)
+      {
+         /* Not a valid 'read' result: */
+         png_warning(png_ptr, "OS /proc read bug");
+         return 0;
+      }
+
+      else if (iread > 0)
+      {
+         /* Continue reading until a permanent failure, or EOF */
+         buffer += iread;
+         nbytes -= (unsigned int)/*SAFE*/iread;
+         ntotal += (unsigned int)/*SAFE*/iread;
+      }
+
+      else
+         return ntotal;
+   }
+
+   return ntotal; /* nbytes == 0 */
+}
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   int fd = open("/proc/self/auxv", O_RDONLY);
+   Elf32_auxv_t aux;
+
+   /* Failsafe: failure to open means no NEON */
+   if (fd == -1)
+   {
+      png_warning(png_ptr, "/proc/self/auxv open failed");
+      return 0;
+   }
+
+   while (safe_read(png_ptr, fd, &aux, sizeof aux) == sizeof aux)
+   {
+      if (aux.a_type == AT_HWCAP && (aux.a_un.a_val & HWCAP_NEON) != 0)
+      {
+         close(fd);
+         return 1;
+      }
+   }
+
+   close(fd);
+   return 0;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/linux.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/linux.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/arm-neon/linux.c	(revision 107811)
@@ -0,0 +1,161 @@
+/* contrib/arm-neon/linux.c
+ *
+ * Copyright (c) 2014, 2017 Glenn Randers-Pehrson
+ * Written by John Bowler, 2014, 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * SEE contrib/arm-neon/README before reporting bugs
+ *
+ * STATUS: SUPPORTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_neon implemented for Linux by reading the widely available
+ * pseudo-file /proc/cpuinfo.
+ *
+ * This code is strict ANSI-C and is probably moderately portable; it does
+ * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ */
+
+#include <stdio.h>
+
+static int
+png_have_neon(png_structp png_ptr)
+{
+   FILE *f = fopen("/proc/cpuinfo", "rb");
+
+   if (f != NULL)
+   {
+      /* This is a simple state machine which reads the input byte-by-byte until
+       * it gets a match on the 'neon' feature or reaches the end of the stream.
+       */
+      static const char ch_feature[] = { 70, 69, 65, 84, 85, 82, 69, 83 };
+      static const char ch_neon[] = { 78, 69, 79, 78 };
+
+      enum
+      {
+         StartLine, Feature, Colon, StartTag, Neon, HaveNeon, SkipTag, SkipLine
+      }  state;
+      int counter;
+
+      for (state=StartLine, counter=0;;)
+      {
+         int ch = fgetc(f);
+
+         if (ch == EOF)
+         {
+            /* EOF means error or end-of-file, return false; neon at EOF is
+             * assumed to be a mistake.
+             */
+            fclose(f);
+            return 0;
+         }
+
+         switch (state)
+         {
+            case StartLine:
+               /* Match spaces at the start of line */
+               if (ch <= 32) /* skip control characters and space */
+                  break;
+
+               counter=0;
+               state = Feature;
+               /* FALLTHROUGH */
+
+            case Feature:
+               /* Match 'FEATURE', ASCII case insensitive. */
+               if ((ch & ~0x20) == ch_feature[counter])
+               {
+                  if (++counter == (sizeof ch_feature))
+                     state = Colon;
+                  break;
+               }
+
+               /* did not match 'feature' */
+               state = SkipLine;
+               /* FALLTHROUGH */
+
+            case SkipLine:
+            skipLine:
+               /* Skip everything until we see linefeed or carriage return */
+               if (ch != 10 && ch != 13)
+                  break;
+
+               state = StartLine;
+               break;
+
+            case Colon:
+               /* Match any number of space or tab followed by ':' */
+               if (ch == 32 || ch == 9)
+                  break;
+
+               if (ch == 58) /* i.e. ':' */
+               {
+                  state = StartTag;
+                  break;
+               }
+
+               /* Either a bad line format or a 'feature' prefix followed by
+                * other characters.
+                */
+               state = SkipLine;
+               goto skipLine;
+
+            case StartTag:
+               /* Skip space characters before a tag */
+               if (ch == 32 || ch == 9)
+                  break;
+
+               state = Neon;
+               counter = 0;
+               /* FALLTHROUGH */
+
+            case Neon:
+               /* Look for 'neon' tag */
+               if ((ch & ~0x20) == ch_neon[counter])
+               {
+                  if (++counter == (sizeof ch_neon))
+                     state = HaveNeon;
+                  break;
+               }
+
+               state = SkipTag;
+               /* FALLTHROUGH */
+
+            case SkipTag:
+               /* Skip non-space characters */
+               if (ch == 10 || ch == 13)
+                  state = StartLine;
+
+               else if (ch == 32 || ch == 9)
+                  state = StartTag;
+               break;
+
+            case HaveNeon:
+               /* Have seen a 'neon' prefix, but there must be a space or new
+                * line character to terminate it.
+                */
+               if (ch == 10 || ch == 13 || ch == 32 || ch == 9)
+               {
+                  fclose(f);
+                  return 1;
+               }
+
+               state = SkipTag;
+               break;
+
+            default:
+               png_error(png_ptr, "png_have_neon: internal error (bug)");
+         }
+      }
+   }
+
+#ifdef PNG_WARNINGS_SUPPORTED
+   else
+      png_warning(png_ptr, "/proc/cpuinfo open failed");
+#endif
+
+   return 0;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/conftest/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/conftest/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/conftest/README	(revision 107811)
@@ -0,0 +1,49 @@
+This directory contains test configuration files, currently always '.dfa' files
+intended to be used in the build by setting the make macro DFA_XTRA to the name
+of the file.
+
+These files are used in release validation of the 'configure' builds of libpng
+by building 'make check', or 'make all-am' for cross-builds, with each .dfa
+file.
+
+The files in this directory may change between minor releases, however
+contributions describing specific builds of libpng are welcomed.  There is no
+guarantee that libpng will continue to build with such configurations; support
+for given configurations can be, and has been, dropped between successive minor
+releases.  However if a .dfa file describing a configuration is not in this
+directory it is very unlikely that it will be tested before a minor release!
+
+You can use these .dfa files as the basis of new configurations.  Files in this
+directory should not have any use restrictions or restrictive licenses.
+
+This directory is not included in the .zip and .7z distributions, which do
+not contain 'configure' scripts.
+
+DOCUMENTATION
+=============
+
+Examples:
+   ${srcdir}/pngusr.dfa
+   ${srcdir}/contrib/pngminim/*/pngusr.dfa
+
+Documentation of the options:
+   ${srcdir}/scripts/pnglibconf.dfa
+
+Documentation of the file format:
+   ${srcdir}/scripts/options.awk
+
+FILE NAMING
+===========
+
+File names in this directory may NOT contain any of the five characters:
+
+   - , + * ?
+
+Neither may they contain any space character.
+
+While other characters may be used it is strongly suggested that file names be
+limited to lower case Latiin alphabetic characters (a-z), digits (0-9) and, if
+necessary the underscore (_) character.  File names should be about 8 characters
+long (excluding the .dfa extension).  Submitted .dfa files should have names
+between 7 and 16 characters long, shorter names (6 characters or less) are
+reserved for standard tests.
Index: /trunk/src/libs/libpng-1.6.45/contrib/conftest/pngcp.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/conftest/pngcp.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/conftest/pngcp.dfa	(revision 107811)
@@ -0,0 +1,57 @@
+# pngcp.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2016
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with support for pngcp.  This means just png_read_png,
+# png_write_png and small number of configuration settings.
+#
+everything = off
+
+# This option is specific to this configuration; it adds a #define to the
+# generated pnglibconf.h which turns on the (not portable) timing option for
+# pngcp.  Note that any option is automatically preceded by PNG_; there is no
+# way round this and this is deliberate.
+option PNGCP_TIMING
+
+# Because of the everything off above the option must also be turned on.  This
+# may not be done in one step because it is safer and avoids mis-spelled options
+# in user .dfa files to error out if an unrecognized option is turned on.
+option PNGCP_TIMING on
+
+# Options to turn on png_read_png and png_write_png:
+option INFO_IMAGE on
+option SEQUENTIAL_READ on
+option EASY_ACCESS on
+option WRITE on
+option WRITE_16BIT on
+option WRITE_FILTER on
+
+# pngcp needs this to preserve unknown chunks, switching all these on means that
+# pngcp can work without explicit known chunk reading support
+option UNKNOWN_CHUNKS on
+option SET_UNKNOWN_CHUNKS on
+option HANDLE_AS_UNKNOWN on
+option SAVE_UNKNOWN_CHUNKS on
+option WRITE_UNKNOWN_CHUNKS on
+
+# pngcp needs this to handle palette files with invalid indices:
+option CHECK_FOR_INVALID_INDEX on
+option GET_PALETTE_MAX on
+
+# Pre-libpng 1.7 pngcp has to stash text chunks manually, post 1.7 without this
+# text chunks should be handled as unknown ok.
+option TEXT on
+
+# this is used to turn off limits:
+option USER_LIMITS on
+option SET_USER_LIMITS on
+
+# these are just required for specific customizations
+option WRITE_CUSTOMIZE_ZTXT_COMPRESSION on
+option WRITE_CUSTOMIZE_COMPRESSION on
Index: /trunk/src/libs/libpng-1.6.45/contrib/conftest/read.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/conftest/read.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/conftest/read.dfa	(revision 107811)
@@ -0,0 +1,58 @@
+# read.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with basic read support.  This enables the lowest level libpng
+# read API - the one where the calling code has to use a loop to read each row.
+# At present this is the API used by most programs.
+#
+# Support is enabled only for those chunks and transformations that are
+# typically required - others can be added easily.
+#
+
+everything = off
+
+# The sequential read code is enabled here; the progressive code can be used
+# instead but there is no point enabling both.
+
+option SEQUENTIAL_READ on
+
+# Likewise it is pointless enabling both fixed and floating point APIs.  Choose
+# one or the other for both the API and the internal math.
+
+#Fixed point:
+#option FIXED_POINT on
+#option FLOATING_ARITHMETIC off
+
+#Floating point:
+option FLOATING_POINT on
+option FLOATING_ARITHMETIC on
+
+# Basic error handling, IO and user memory support.  The latter allows the
+# application program to provide its own implementations of 'malloc' and 'free'.
+option SETJMP on
+option STDIO on
+option USER_MEM on
+
+# To read the full set of PNG images correctly interlace, transparency and
+# 16-bit support is required.  The application can implement interlace itself,
+# but very few do and it's no longer possible to disable it when READ is
+# enabled.
+option READ_tRNS on
+option READ_16BIT on
+
+# Everything else is application dependent.  This file assumes the app handles
+# all the native PNG bit layouts, so it doesn't need any of layout change
+# transforms, but needs libpng to perform gamma correction.  It doesn't do any
+# colorspace stuff and ignores the 'significant bit' information.
+#
+# If your app always expands the image to a limited set of bit layouts you
+# probably want to consider using the simplified API instead of the low level
+# one - see png.h and s_read.dfa.
+option READ_GAMMA on
Index: /trunk/src/libs/libpng-1.6.45/contrib/conftest/s_read.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/conftest/s_read.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/conftest/s_read.dfa	(revision 107811)
@@ -0,0 +1,35 @@
+# s_read.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with simplified read support (only).  This builds a minimal
+# libpng able to read all PNG formats and convert them into a small number of
+# well understood memory formats.
+#
+
+everything = off
+
+option SIMPLIFIED_READ on
+
+# It isn't necessary to chose fixed or floating point for the APIs because the
+# simplified API doesn't need fixed or floating point numbers.  It is necessary
+# to chose an internal math implementation.  The default (because of 'everything
+# = off') is fixed point - turn the floating point implementation on if you have
+# hardware floating point or prefer your software floating point implementation.
+option FLOATING_ARITHMETIC on
+
+# This is not strictly necessary, but without it the message strings in the API
+# will not be filled in
+option ERROR_TEXT on
+
+# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
+# need this if you don't use them, they just allow the in-memory layout to be
+# changed to match common hardware formats.
+option SIMPLIFIED_READ_AFIRST on
+option SIMPLIFIED_READ_BGR on
Index: /trunk/src/libs/libpng-1.6.45/contrib/conftest/s_write.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/conftest/s_write.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/conftest/s_write.dfa	(revision 107811)
@@ -0,0 +1,33 @@
+# s_write.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with (just) simplified write support
+#
+
+everything = off
+
+option SIMPLIFIED_WRITE on
+
+# It isn't necessary to chose fixed or floating point for the APIs because the
+# simplified API doesn't need fixed or floating point numbers.  It is necessary
+# to chose an internal math implementation.  The default (because of 'everything
+# = off') is fixed point - turn the floating point implementation on if you have
+# hardware floating point or prefer your software floating point implementation.
+option FLOATING_ARITHMETIC on
+
+# This is not strictly necessary, but without it the message strings in the API
+# will not be filled in
+option ERROR_TEXT on
+
+# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
+# need this if you don't use them, they just allow the in-memory layout to be
+# changed to match common hardware formats.
+option SIMPLIFIED_WRITE_AFIRST on
+option SIMPLIFIED_WRITE_BGR on
Index: /trunk/src/libs/libpng-1.6.45/contrib/conftest/simple.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/conftest/simple.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/conftest/simple.dfa	(revision 107811)
@@ -0,0 +1,36 @@
+# simple.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with just the simplified APIs (read and write).
+#
+
+everything = off
+
+option SIMPLIFIED_WRITE on
+option SIMPLIFIED_READ on
+
+# It isn't necessary to chose fixed or floating point for the APIs because the
+# simplified API doesn't need fixed or floating point numbers.  It is necessary
+# to chose an internal math implementation.  The default (because of 'everything
+# = off') is fixed point - turn the floating point implementation on if you have
+# hardware floating point or prefer your software floating point implementation.
+option FLOATING_ARITHMETIC on
+
+# This is not strictly necessary, but without it the message strings in the API
+# will not be filled in
+option ERROR_TEXT on
+
+# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
+# need this if you don't use them, they just allow the in-memory layout to be
+# changed to match common hardware formats.
+option SIMPLIFIED_READ_AFIRST on
+option SIMPLIFIED_READ_BGR on
+option SIMPLIFIED_WRITE_AFIRST on
+option SIMPLIFIED_WRITE_BGR on
Index: /trunk/src/libs/libpng-1.6.45/contrib/conftest/write.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/conftest/write.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/conftest/write.dfa	(revision 107811)
@@ -0,0 +1,45 @@
+# write.dfa
+#  Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2013
+# Usage rights:
+#  To the extent possible under law, the author has waived all copyright and
+#  related or neighboring rights to this work.  This work is published from:
+#  United States.
+#
+# Build libpng with no read support and minimal write support.
+#
+
+everything = off
+
+# Switch on the write code - this makes a minimalist encoder
+
+option WRITE on
+
+# Choose fixed or floating point APIs and arithmetic.  The choices are
+# independent but normally they will match.  It is typically better to use the
+# floating point if you have floating point hardware.  If you don't know, or
+# (perhaps) to make libpng smaller used fixed point throughout.
+
+#Fixed point:
+#option FIXED_POINT on
+#option FLOATING_ARITHMETIC off
+
+#Floating point:
+option FLOATING_POINT on
+option FLOATING_ARITHMETIC on
+
+# Basic error handling, IO and user memory support.  The latter allows the
+# application program to provide its own implementations of 'malloc' and 'free'.
+option SETJMP on
+option STDIO on
+option USER_MEM on
+
+# Everything else is optional.  Unlike the read code in libpng the write code
+# does not need to deal with arbitrary formats, so only add support for things
+# you really do write!  For example you might only write sRGB images, sometimes
+# with transparency and never write 16 bit images, so:
+option WRITE_sRGB on
+option WRITE_tRNS on
+#option WRITE_16BIT off (this is the default with 'everything = off')
Index: /trunk/src/libs/libpng-1.6.45/contrib/examples/README.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/examples/README.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/examples/README.txt	(revision 107811)
@@ -0,0 +1,24 @@
+
+This directory (contrib/examples) contains examples of libpng usage.
+
+NO COPYRIGHT RIGHTS ARE CLAIMED TO ANY OF THE FILES IN THIS DIRECTORY.
+
+To the extent possible under law, the authors have waived all copyright and
+related or neighboring rights to this work.  This work is published from:
+United States.
+
+The files may be used freely in any way.  The intention is that appropriate
+parts of the files be used in other libpng-using programs without any need for
+the authors of the using code to seek copyright or license from the original
+authors.
+
+The source code and comments in this directory are the original work of the
+people named below.  No other person or organization has made contributions to
+the work in this directory.
+
+ORIGINAL AUTHORS
+    The following people have contributed to the code in this directory.  None
+    of the people below claim any rights with regard to the contents of this
+    directory.
+
+    John Bowler <jbowler at acm.org>
Index: /trunk/src/libs/libpng-1.6.45/contrib/examples/iccfrompng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/examples/iccfrompng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/examples/iccfrompng.c	(revision 107811)
@@ -0,0 +1,185 @@
+/*- iccfrompng
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Extract any icc profiles found in the given PNG files.  This is a simple
+ * example of a program that extracts information from the header of a PNG file
+ * without processing the image.  Notice that some header information may occur
+ * after the image data. Textual data and comments are an example; the approach
+ * in this file won't work reliably for such data because it only looks for the
+ * information in the section of the file that precedes the image data.
+ *
+ * Compile and link against libpng and zlib, plus anything else required on the
+ * system you use.
+ *
+ * To use supply a list of PNG files containing iCCP chunks, the chunks will be
+ * extracted to a similarly named file with the extension replaced by 'icc',
+ * which will be overwritten without warning.
+ */
+#include <stdlib.h>
+#include <setjmp.h>
+#include <string.h>
+#include <stdio.h>
+
+#include <png.h>
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \
+    defined (PNG_iCCP_SUPPORTED)
+
+
+static int verbose = 1;
+static png_byte no_profile[] = "no profile";
+
+static png_bytep
+extract(FILE *fp, png_uint_32 *proflen)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
+   png_infop info_ptr = NULL;
+   png_bytep result = NULL;
+
+   /* Initialize for error or no profile: */
+   *proflen = 0;
+
+   if (png_ptr == NULL)
+   {
+      fprintf(stderr, "iccfrompng: version library mismatch?\n");
+      return 0;
+   }
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      return 0;
+   }
+
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   png_read_info(png_ptr, info_ptr);
+
+   {
+      png_charp name;
+      int compression_type;
+      png_bytep profile;
+
+      if (png_get_iCCP(png_ptr, info_ptr, &name, &compression_type, &profile,
+         proflen) & PNG_INFO_iCCP)
+      {
+         result = malloc(*proflen);
+         if (result != NULL)
+            memcpy(result, profile, *proflen);
+
+         else
+            png_error(png_ptr, "OOM allocating profile buffer");
+      }
+
+      else
+         result = no_profile;
+   }
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   return result;
+}
+
+static int
+extract_one_file(const char *filename)
+{
+   int result = 0;
+   FILE *fp = fopen(filename, "rb");
+
+   if (fp != NULL)
+   {
+      png_uint_32 proflen = 0;
+      png_bytep profile = extract(fp, &proflen);
+
+      if (profile != NULL && profile != no_profile)
+      {
+         size_t len;
+         char *output;
+
+         {
+            const char *ep = strrchr(filename, '.');
+
+            if (ep != NULL)
+               len = ep-filename;
+
+            else
+               len = strlen(filename);
+         }
+
+         output = malloc(len + 5);
+         if (output != NULL)
+         {
+            FILE *of;
+
+            memcpy(output, filename, len);
+            strcpy(output+len, ".icc");
+
+            of = fopen(output, "wb");
+            if (of != NULL)
+            {
+               if (fwrite(profile, proflen, 1, of) == 1 &&
+                  fflush(of) == 0 &&
+                  fclose(of) == 0)
+               {
+                  if (verbose)
+                     printf("%s -> %s\n", filename, output);
+                  /* Success return */
+                  result = 1;
+               }
+
+               else
+               {
+                  fprintf(stderr, "%s: error writing profile\n", output);
+                  if (remove(output))
+                     fprintf(stderr, "%s: could not remove file\n", output);
+               }
+            }
+
+            else
+               fprintf(stderr, "%s: failed to open output file\n", output);
+
+            free(output);
+         }
+
+         else
+            fprintf(stderr, "%s: OOM allocating string!\n", filename);
+
+         free(profile);
+      }
+
+      else if (verbose && profile == no_profile)
+         printf("%s has no profile\n", filename);
+   }
+
+   else
+      fprintf(stderr, "%s: could not open file\n", filename);
+
+   return result;
+}
+
+int
+main(int argc, char **argv)
+{
+   int i;
+   int extracted = 0;
+
+   for (i=1; i<argc; ++i)
+   {
+      if (strcmp(argv[i], "-q") == 0)
+         verbose = 0;
+
+      else if (extract_one_file(argv[i]))
+         extracted = 1;
+   }
+
+   /* Exit code is true if any extract succeeds */
+   return extracted == 0;
+}
+#endif /* READ && STDIO && iCCP */
Index: /trunk/src/libs/libpng-1.6.45/contrib/examples/pngpixel.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/examples/pngpixel.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/examples/pngpixel.c	(revision 107811)
@@ -0,0 +1,371 @@
+/*- pngpixel
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Read a single pixel value from a PNG file.
+ *
+ * This code illustrates basic 'by-row' reading of a PNG file using libpng.
+ * Rows are read until a particular pixel is found; the value of this pixel is
+ * then printed on stdout.
+ *
+ * The code illustrates how to do this on interlaced as well as non-interlaced
+ * images.  Normally you would call png_set_interlace_handling() to have libpng
+ * deal with the interlace for you, but that obliges you to buffer half of the
+ * image to assemble the interlaced rows.  In this code
+ * png_set_interlace_handling() is not called and, instead, the code handles the
+ * interlace passes directly looking for the required pixel.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <setjmp.h> /* required for error handling */
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation:
+ */
+#include "../../png.h"
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+
+/* Return component 'c' of pixel 'x' from the given row. */
+static unsigned int
+component(png_const_bytep row, png_uint_32 x, unsigned int c,
+   unsigned int bit_depth, unsigned int channels)
+{
+   /* PNG images can be up to 2^31 pixels wide, but this means they can be up to
+    * 2^37 bits wide (for a 64-bit pixel - the largest possible) and hence 2^34
+    * bytes wide.  Since the row fitted into memory, however, the following must
+    * work:
+    */
+   png_uint_32 bit_offset_hi = bit_depth * ((x >> 6) * channels);
+   png_uint_32 bit_offset_lo = bit_depth * ((x & 0x3f) * channels + c);
+
+   row = (png_const_bytep)(((const png_byte (*)[8])row) + bit_offset_hi);
+   row += bit_offset_lo >> 3;
+   bit_offset_lo &= 0x07;
+
+   /* PNG pixels are packed into bytes to put the first pixel in the highest
+    * bits of the byte and into two bytes for 16-bit values with the high 8 bits
+    * first, so:
+    */
+   switch (bit_depth)
+   {
+      case 1: return (row[0] >> (7-bit_offset_lo)) & 0x01;
+      case 2: return (row[0] >> (6-bit_offset_lo)) & 0x03;
+      case 4: return (row[0] >> (4-bit_offset_lo)) & 0x0f;
+      case 8: return row[0];
+      case 16: return (row[0] << 8) + row[1];
+      default:
+         /* This should never happen; it indicates a bug in this program or in
+          * libpng itself:
+          */
+         fprintf(stderr, "pngpixel: invalid bit depth %u\n", bit_depth);
+         exit(1);
+   }
+}
+
+/* Print a pixel from a row returned by libpng; determine the row format, find
+ * the pixel, and print the relevant information to stdout.
+ */
+static void
+print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
+   png_uint_32 x)
+{
+   unsigned int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
+
+   switch (png_get_color_type(png_ptr, info_ptr))
+   {
+      case PNG_COLOR_TYPE_GRAY:
+         printf("GRAY %u\n", component(row, x, 0, bit_depth, 1));
+         return;
+
+      /* The palette case is slightly more difficult - the palette and, if
+       * present, the tRNS ('transparency', though the values are really
+       * opacity) data must be read to give the full picture:
+       */
+      case PNG_COLOR_TYPE_PALETTE:
+         {
+            int index = component(row, x, 0, bit_depth, 1);
+            png_colorp palette = NULL;
+            int num_palette = 0;
+
+            if ((png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) &
+               PNG_INFO_PLTE) && num_palette > 0 && palette != NULL)
+            {
+               png_bytep trans_alpha = NULL;
+               int num_trans = 0;
+               if ((png_get_tRNS(png_ptr, info_ptr, &trans_alpha, &num_trans,
+                  NULL) & PNG_INFO_tRNS) && num_trans > 0 &&
+                  trans_alpha != NULL)
+                  printf("INDEXED %u = %d %d %d %d\n", index,
+                     palette[index].red, palette[index].green,
+                     palette[index].blue,
+                     index < num_trans ? trans_alpha[index] : 255);
+
+               else /* no transparency */
+                  printf("INDEXED %u = %d %d %d\n", index,
+                     palette[index].red, palette[index].green,
+                     palette[index].blue);
+            }
+
+            else
+               printf("INDEXED %u = invalid index\n", index);
+         }
+         return;
+
+      case PNG_COLOR_TYPE_RGB:
+         printf("RGB %u %u %u\n", component(row, x, 0, bit_depth, 3),
+            component(row, x, 1, bit_depth, 3),
+            component(row, x, 2, bit_depth, 3));
+         return;
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         printf("GRAY+ALPHA %u %u\n", component(row, x, 0, bit_depth, 2),
+            component(row, x, 1, bit_depth, 2));
+         return;
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         printf("RGBA %u %u %u %u\n", component(row, x, 0, bit_depth, 4),
+            component(row, x, 1, bit_depth, 4),
+            component(row, x, 2, bit_depth, 4),
+            component(row, x, 3, bit_depth, 4));
+         return;
+
+      default:
+         png_error(png_ptr, "pngpixel: invalid color type");
+   }
+}
+
+int main(int argc, const char **argv)
+{
+   /* This program uses the default, <setjmp.h> based, libpng error handling
+    * mechanism, therefore any local variable that exists before the call to
+    * setjmp and is changed after the call to setjmp returns successfully must
+    * be declared with 'volatile' to ensure that their values don't get
+    * destroyed by longjmp:
+    */
+   volatile int result = 1/*fail*/;
+
+   if (argc == 4)
+   {
+      long x = atol(argv[1]);
+      long y = atol(argv[2]);
+      FILE *f = fopen(argv[3], "rb");
+      volatile png_bytep row = NULL;
+
+      if (f != NULL)
+      {
+         /* libpng requires a callback function for handling errors; this
+          * callback must not return.  The default callback function uses a
+          * stored <setjmp.h> style jmp_buf which is held in a png_struct and
+          * writes error messages to stderr.  Creating the png_struct is a
+          * little tricky; just copy the following code.
+          */
+         png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+            NULL, NULL, NULL);
+
+         if (png_ptr != NULL)
+         {
+            png_infop info_ptr = png_create_info_struct(png_ptr);
+
+            if (info_ptr != NULL)
+            {
+               /* Declare stack variables to hold pointers to locally allocated
+                * data.
+                */
+
+               /* Initialize the error control buffer: */
+               if (setjmp(png_jmpbuf(png_ptr)) == 0)
+               {
+                  png_uint_32 width, height;
+                  int bit_depth, color_type, interlace_method,
+                     compression_method, filter_method;
+                  png_bytep row_tmp;
+
+                  /* Now associate the recently opened (FILE*) with the default
+                   * libpng initialization functions.  Sometimes libpng is
+                   * compiled without stdio support (it can be difficult to do
+                   * in some environments); in that case you will have to write
+                   * your own read callback to read data from the (FILE*).
+                   */
+                  png_init_io(png_ptr, f);
+
+                  /* And read the first part of the PNG file - the header and
+                   * all the information up to the first pixel.
+                   */
+                  png_read_info(png_ptr, info_ptr);
+
+                  /* This fills in enough information to tell us the width of
+                   * each row in bytes, allocate the appropriate amount of
+                   * space.  In this case png_malloc is used - it will not
+                   * return if memory isn't available.
+                   */
+                  row = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
+                     info_ptr));
+
+                  /* To avoid the overhead of using a volatile auto copy row_tmp
+                   * to a local here - just use row for the png_free below.
+                   */
+                  row_tmp = row;
+
+                  /* All the information we need is in the header is returned by
+                   * png_get_IHDR, if this fails we can now use 'png_error' to
+                   * signal the error and return control to the setjmp above.
+                   */
+                  if (png_get_IHDR(png_ptr, info_ptr, &width, &height,
+                     &bit_depth, &color_type, &interlace_method,
+                     &compression_method, &filter_method))
+                  {
+                     int passes, pass;
+
+                     /* png_set_interlace_handling returns the number of
+                      * passes required as well as turning on libpng's
+                      * handling, but since we do it ourselves this is
+                      * necessary:
+                      */
+                     switch (interlace_method)
+                     {
+                        case PNG_INTERLACE_NONE:
+                           passes = 1;
+                           break;
+
+                        case PNG_INTERLACE_ADAM7:
+                           passes = PNG_INTERLACE_ADAM7_PASSES;
+                           break;
+
+                        default:
+                           png_error(png_ptr, "pngpixel: unknown interlace");
+                     }
+
+                     /* Now read the pixels, pass-by-pass, row-by-row: */
+                     png_start_read_image(png_ptr);
+
+                     for (pass=0; pass<passes; ++pass)
+                     {
+                        png_uint_32 ystart, xstart, ystep, xstep;
+                        png_uint_32 py;
+
+                        if (interlace_method == PNG_INTERLACE_ADAM7)
+                        {
+                           /* Sometimes the whole pass is empty because the
+                            * image is too narrow or too short.  libpng
+                            * expects to be called for each row that is
+                            * present in the pass, so it may be necessary to
+                            * skip the loop below (over py) if the image is
+                            * too narrow.
+                            */
+                           if (PNG_PASS_COLS(width, pass) == 0)
+                              continue;
+
+                           /* We need the starting pixel and the offset
+                            * between each pixel in this pass; use the macros
+                            * in png.h:
+                            */
+                           xstart = PNG_PASS_START_COL(pass);
+                           ystart = PNG_PASS_START_ROW(pass);
+                           xstep = PNG_PASS_COL_OFFSET(pass);
+                           ystep = PNG_PASS_ROW_OFFSET(pass);
+                        }
+
+                        else
+                        {
+                           ystart = xstart = 0;
+                           ystep = xstep = 1;
+                        }
+
+                        /* To find the pixel, loop over 'py' for each pass
+                         * reading a row and then checking to see if it
+                         * contains the pixel.
+                         */
+                        for (py = ystart; py < height; py += ystep)
+                        {
+                           png_uint_32 px, ppx;
+
+                           /* png_read_row takes two pointers.  When libpng
+                            * handles the interlace the first is filled in
+                            * pixel-by-pixel, and the second receives the same
+                            * pixels but they are replicated across the
+                            * unwritten pixels so far for each pass.  When we
+                            * do the interlace, however, they just contain
+                            * the pixels from the interlace pass - giving
+                            * both is wasteful and pointless, so we pass a
+                            * NULL pointer.
+                            */
+                           png_read_row(png_ptr, row_tmp, NULL);
+
+                           /* Now find the pixel if it is in this row; there
+                            * are, of course, much better ways of doing this
+                            * than using a for loop:
+                            */
+                           if (y == py) for (px = xstart, ppx = 0;
+                              px < width; px += xstep, ++ppx) if (x == px)
+                           {
+                              /* 'ppx' is the index of the pixel in the row
+                               * buffer.
+                               */
+                              print_pixel(png_ptr, info_ptr, row_tmp, ppx);
+
+                              /* Now terminate the loops early - we have
+                               * found and handled the required data.
+                               */
+                              goto pass_loop_end;
+                           } /* x loop */
+                        } /* y loop */
+                     } /* pass loop */
+
+                     /* Finally free the temporary buffer: */
+                  pass_loop_end:
+                     row = NULL;
+                     png_free(png_ptr, row_tmp);
+                  }
+
+                  else
+                     png_error(png_ptr, "pngpixel: png_get_IHDR failed");
+
+               }
+
+               else
+               {
+                  /* Else libpng has raised an error.  An error message has
+                   * already been output, so it is only necessary to clean up
+                   * locally allocated data:
+                   */
+                  if (row != NULL)
+                  {
+                     /* The default implementation of png_free never errors out
+                      * (it just crashes if something goes wrong), but the safe
+                      * way of using it is still to clear 'row' before calling
+                      * png_free:
+                      */
+                     png_bytep row_tmp = row;
+                     row = NULL;
+                     png_free(png_ptr, row_tmp);
+                  }
+               }
+
+               png_destroy_info_struct(png_ptr, &info_ptr);
+            }
+
+            else
+               fprintf(stderr, "pngpixel: out of memory allocating png_info\n");
+
+            png_destroy_read_struct(&png_ptr, NULL, NULL);
+         }
+
+         else
+            fprintf(stderr, "pngpixel: out of memory allocating png_struct\n");
+      }
+
+      else
+         fprintf(stderr, "pngpixel: %s: could not open file\n", argv[3]);
+   }
+
+   else
+      /* Wrong number of arguments */
+      fprintf(stderr, "pngpixel: usage: pngpixel x y png-file\n");
+
+   return result;
+}
+#endif /* READ && SEQUENTIAL_READ */
Index: /trunk/src/libs/libpng-1.6.45/contrib/examples/pngtopng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/examples/pngtopng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/examples/pngtopng.c	(revision 107811)
@@ -0,0 +1,96 @@
+/*- pngtopng
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2011, 2017.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Read a PNG and write it out in a fixed format, using the 'simplified API'
+ * that was introduced in libpng-1.6.0.
+ *
+ * This sample code is just the code from the top of 'example.c' with some error
+ * handling added.  See example.c for more comments.
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation:
+ */
+#include "../../png.h"
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && \
+    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+
+int main(int argc, const char **argv)
+{
+   int result = 1;
+
+   if (argc == 3)
+   {
+      png_image image;
+
+      /* Only the image structure version number needs to be set. */
+      memset(&image, 0, sizeof image);
+      image.version = PNG_IMAGE_VERSION;
+
+      if (png_image_begin_read_from_file(&image, argv[1]))
+      {
+         png_bytep buffer;
+
+         /* Change this to try different formats!  If you set a colormap format
+          * then you must also supply a colormap below.
+          */
+         image.format = PNG_FORMAT_RGBA;
+
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         if (buffer != NULL)
+         {
+            if (png_image_finish_read(&image, NULL/*background*/, buffer,
+               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
+            {
+               if (png_image_write_to_file(&image, argv[2],
+                  0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                  NULL/*colormap*/))
+                  result = 0;
+
+               else
+                  fprintf(stderr, "pngtopng: write %s: %s\n", argv[2],
+                      image.message);
+            }
+
+            else
+               fprintf(stderr, "pngtopng: read %s: %s\n", argv[1],
+                   image.message);
+
+            free(buffer);
+         }
+
+         else
+         {
+            fprintf(stderr, "pngtopng: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+
+            /* This is the only place where a 'free' is required; libpng does
+             * the cleanup on error and success, but in this case we couldn't
+             * complete the read because of running out of memory and so libpng
+             * has not got to the point where it can do cleanup.
+             */
+            png_image_free(&image);
+         }
+      }
+
+      else
+         /* Failed to read the first argument: */
+         fprintf(stderr, "pngtopng: %s: %s\n", argv[1], image.message);
+   }
+
+   else
+      /* Wrong number of arguments */
+      fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n");
+
+   return result;
+}
+#endif /* READ && WRITE */
Index: /trunk/src/libs/libpng-1.6.45/contrib/examples/simpleover.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/examples/simpleover.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/examples/simpleover.c	(revision 107811)
@@ -0,0 +1,648 @@
+/*- simpleover
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2015.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Read several PNG files, which should have an alpha channel or transparency
+ * information, and composite them together to produce one or more 16-bit linear
+ * RGBA intermediates.  This involves doing the correct 'over' composition to
+ * combine the alpha channels and corresponding data.
+ *
+ * Finally read an output (background) PNG using the 24-bit RGB format (the
+ * PNG will be composited on green (#00ff00) by default if it has an alpha
+ * channel), and apply the intermediate image generated above to specified
+ * locations in the image.
+ *
+ * The command line has the general format:
+ *
+ *    simpleover <background.png> [output.png]
+ *        {--sprite=width,height,name {[--at=x,y] {sprite.png}}}
+ *        {--add=name {x,y}}
+ *
+ * The --sprite and --add options may occur multiple times. They are executed
+ * in order.  --add may refer to any sprite already read.
+ *
+ * This code is intended to show how to composite multiple images together
+ * correctly.  Apart from the libpng Simplified API the only work done in here
+ * is to combine multiple input PNG images into a single sprite; this involves
+ * a Porter-Duff 'over' operation and the input PNG images may, as a result,
+ * be regarded as being layered one on top of the other with the first (leftmost
+ * on the command line) being at the bottom and the last on the top.
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation, so long as this
+ * file is linked against a sufficiently recent libpng (1.6+) it is ok to
+ * change this to <png.h>:
+ */
+#include "../../png.h"
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+
+#define sprite_name_chars 15
+struct sprite {
+   FILE         *file;
+   png_uint_16p  buffer;
+   unsigned int  width;
+   unsigned int  height;
+   char          name[sprite_name_chars+1];
+};
+
+#if 0 /* div by 65535 test program */
+#include <math.h>
+#include <stdio.h>
+
+int main(void) {
+   double err = 0;
+   unsigned int xerr = 0;
+   unsigned int r = 32769;
+   {
+      unsigned int x = 0;
+
+      do {
+         unsigned int t = x + (x >> 16) /*+ (x >> 31)*/ + r;
+         double v = x, errtest;
+
+         if (t < x) {
+            fprintf(stderr, "overflow: %u+%u -> %u\n", x, r, t);
+            return 1;
+         }
+
+         v /= 65535;
+         errtest = v;
+         t >>= 16;
+         errtest -= t;
+
+         if (errtest > err) {
+            err = errtest;
+            xerr = x;
+
+            if (errtest >= .5) {
+               fprintf(stderr, "error: %u/65535 = %f, not %u, error %f\n",
+                     x, v, t, errtest);
+               return 0;
+            }
+         }
+      } while (++x <= 65535U*65535U);
+   }
+
+   printf("error %f @ %u\n", err, xerr);
+
+   return 0;
+}
+#endif /* div by 65535 test program */
+
+static void
+sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
+   png_imagep image, const png_uint_16 *buffer)
+{
+   /* This is where the Porter-Duff 'Over' operator is evaluated; change this
+    * code to change the operator (this could be parameterized).  Any other
+    * image processing operation could be used here.
+    */
+
+
+   /* Check for an x or y offset that pushes any part of the image beyond the
+    * right or bottom of the sprite:
+    */
+   if ((y_offset < 0 || (unsigned)/*SAFE*/y_offset < sprite->height) &&
+       (x_offset < 0 || (unsigned)/*SAFE*/x_offset < sprite->width))
+   {
+      unsigned int y = 0;
+
+      if (y_offset < 0)
+         y = -y_offset; /* Skip to first visible row */
+
+      do
+      {
+         unsigned int x = 0;
+
+         if (x_offset < 0)
+            x = -x_offset;
+
+         do
+         {
+            /* In and out are RGBA values, so: */
+            const png_uint_16 *in_pixel = buffer + (y * image->width + x)*4;
+            png_uint_32 in_alpha = in_pixel[3];
+
+            /* This is the optimized Porter-Duff 'Over' operation, when the
+             * input alpha is 0 the output is not changed.
+             */
+            if (in_alpha > 0)
+            {
+               png_uint_16 *out_pixel = sprite->buffer +
+                  ((y+y_offset) * sprite->width + (x+x_offset))*4;
+
+               /* This is the weight to apply to the output: */
+               in_alpha = 65535-in_alpha;
+
+               if (in_alpha > 0)
+               {
+                  /* The input must be composed onto the output. This means
+                   * multiplying the current output pixel value by the inverse
+                   * of the input alpha (1-alpha). A division is required but
+                   * it is by the constant 65535.  Approximate this as:
+                   *
+                   *     (x + (x >> 16) + 32769) >> 16;
+                   *
+                   * This is exact (and does not overflow) for all values of
+                   * x in the range 0..65535*65535.  (Note that the calculation
+                   * produces the closest integer; the maximum error is <0.5).
+                   */
+                  png_uint_32 tmp;
+
+#                 define compose(c)\
+                     tmp = out_pixel[c] * in_alpha;\
+                     tmp = (tmp + (tmp >> 16) + 32769) >> 16;\
+                     out_pixel[c] = tmp + in_pixel[c]
+
+                  /* The following is very vectorizable... */
+                  compose(0);
+                  compose(1);
+                  compose(2);
+                  compose(3);
+               }
+
+               else
+                  out_pixel[0] = in_pixel[0],
+                  out_pixel[1] = in_pixel[1],
+                  out_pixel[2] = in_pixel[2],
+                  out_pixel[3] = in_pixel[3];
+            }
+         }
+         while (++x < image->width);
+      }
+      while (++y < image->height);
+   }
+}
+
+static int
+create_sprite(struct sprite *sprite, int *argc, const char ***argv)
+{
+   /* Read the arguments and create this sprite. The sprite buffer has already
+    * been allocated. This reads the input PNGs one by one in linear format,
+    * composes them onto the sprite buffer (the code in the function above)
+    * then saves the result, converting it on the fly to PNG RGBA 8-bit format.
+    */
+   while (*argc > 0)
+   {
+      char tombstone;
+      int x = 0, y = 0;
+
+      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
+      {
+         /* The only supported option is --at. */
+         if (sscanf((*argv)[0], "--at=%d,%d%c", &x, &y, &tombstone) != 2)
+            break; /* success; caller will parse this option */
+
+         ++*argv, --*argc;
+      }
+
+      else
+      {
+         /* The argument has to be a file name */
+         png_image image;
+
+         image.version = PNG_IMAGE_VERSION;
+         image.opaque = NULL;
+
+         if (png_image_begin_read_from_file(&image, (*argv)[0]))
+         {
+            png_uint_16p buffer;
+
+            image.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+
+            buffer = malloc(PNG_IMAGE_SIZE(image));
+
+            if (buffer != NULL)
+            {
+               if (png_image_finish_read(&image, NULL/*background*/, buffer,
+                  0/*row_stride*/,
+                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+               {
+                  /* This is the place where the Porter-Duff 'Over' operator
+                   * needs to be done by this code.  In fact, any image
+                   * processing required can be done here; the data is in
+                   * the correct format (linear, 16-bit) and source and
+                   * destination are in memory.
+                   */
+                  sprite_op(sprite, x, y, &image, buffer);
+                  free(buffer);
+                  ++*argv, --*argc;
+                  /* And continue to the next argument */
+                  continue;
+               }
+
+               else
+               {
+                  free(buffer);
+                  fprintf(stderr, "simpleover: read %s: %s\n", (*argv)[0],
+                      image.message);
+               }
+            }
+
+            else
+            {
+               fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
+                  (unsigned long)PNG_IMAGE_SIZE(image));
+
+               /* png_image_free must be called if we abort the Simplified API
+                * read because of a problem detected in this code.  If problems
+                * are detected in the Simplified API it cleans up itself.
+                */
+               png_image_free(&image);
+            }
+         }
+
+         else
+         {
+            /* Failed to read the first argument: */
+            fprintf(stderr, "simpleover: %s: %s\n", (*argv)[0], image.message);
+         }
+
+         return 0; /* failure */
+      }
+   }
+
+   /* All the sprite operations have completed successfully. Save the RGBA
+    * buffer as a PNG using the simplified write API.
+    */
+   sprite->file = tmpfile();
+
+   if (sprite->file != NULL)
+   {
+      png_image save;
+
+      memset(&save, 0, sizeof save);
+      save.version = PNG_IMAGE_VERSION;
+      save.opaque = NULL;
+      save.width = sprite->width;
+      save.height = sprite->height;
+      save.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+      save.flags = PNG_IMAGE_FLAG_FAST;
+      save.colormap_entries = 0;
+
+      if (png_image_write_to_stdio(&save, sprite->file, 1/*convert_to_8_bit*/,
+          sprite->buffer, 0/*row_stride*/, NULL/*colormap*/))
+      {
+         /* Success; the buffer is no longer needed: */
+         free(sprite->buffer);
+         sprite->buffer = NULL;
+         return 1; /* ok */
+      }
+
+      else
+         fprintf(stderr, "simpleover: write sprite %s: %s\n", sprite->name,
+            save.message);
+   }
+
+   else
+      fprintf(stderr, "simpleover: sprite %s: could not allocate tmpfile: %s\n",
+         sprite->name, strerror(errno));
+
+   return 0; /* fail */
+}
+
+static int
+add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
+   int *argc, const char ***argv)
+{
+   /* Given a --add argument naming this sprite, perform the operations listed
+    * in the following arguments.  The arguments are expected to have the form
+    * (x,y), which is just an offset at which to add the sprite to the
+    * output.
+    */
+   while (*argc > 0)
+   {
+      char tombstone;
+      int x, y;
+
+      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
+         return 1; /* success */
+
+      if (sscanf((*argv)[0], "%d,%d%c", &x, &y, &tombstone) == 2)
+      {
+         /* Now add the new image into the sprite data, but only if it
+          * will fit.
+          */
+         if (x < 0 || y < 0 ||
+             (unsigned)/*SAFE*/x >= output->width ||
+             (unsigned)/*SAFE*/y >= output->height ||
+             sprite->width > output->width-x ||
+             sprite->height > output->height-y)
+         {
+            fprintf(stderr, "simpleover: sprite %s @ (%d,%d) outside image\n",
+               sprite->name, x, y);
+            /* Could just skip this, but for the moment it is an error */
+            return 0; /* error */
+         }
+
+         else
+         {
+            /* Since we know the sprite fits we can just read it into the
+             * output using the simplified API.
+             */
+            png_image in;
+
+            in.version = PNG_IMAGE_VERSION;
+            rewind(sprite->file);
+
+            if (png_image_begin_read_from_stdio(&in, sprite->file))
+            {
+               in.format = PNG_FORMAT_RGB; /* force compose */
+
+               if (png_image_finish_read(&in, NULL/*background*/,
+                  out_buf + (y*output->width + x)*3/*RGB*/,
+                  output->width*3/*row_stride*/,
+                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
+               {
+                  ++*argv, --*argc;
+                  continue;
+               }
+            }
+
+            /* The read failed: */
+            fprintf(stderr, "simpleover: add sprite %s: %s\n", sprite->name,
+                in.message);
+            return 0; /* error */
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "simpleover: --add='%s': invalid position %s\n",
+               sprite->name, (*argv)[0]);
+         return 0; /* error */
+      }
+   }
+
+   return 1; /* ok */
+}
+
+static int
+simpleover_process(png_imagep output, png_bytep out_buf, int argc,
+   const char **argv)
+{
+   int result = 1; /* success */
+#  define csprites 10/*limit*/
+#  define str(a) #a
+   int nsprites = 0;
+   struct sprite sprites[csprites];
+
+   while (argc > 0)
+   {
+      result = 0; /* fail */
+
+      if (strncmp(argv[0], "--sprite=", 9) == 0)
+      {
+         char tombstone;
+
+         if (nsprites < csprites)
+         {
+            int n;
+
+            sprites[nsprites].width = sprites[nsprites].height = 0;
+            sprites[nsprites].name[0] = 0;
+
+            n = sscanf(argv[0], "--sprite=%u,%u,%" str(sprite_name_chars) "s%c",
+                &sprites[nsprites].width, &sprites[nsprites].height,
+                sprites[nsprites].name, &tombstone);
+
+            if ((n == 2 || n == 3) &&
+                sprites[nsprites].width > 0 && sprites[nsprites].height > 0)
+            {
+               size_t buf_size, tmp;
+
+               /* Default a name if not given. */
+               if (sprites[nsprites].name[0] == 0)
+                  sprintf(sprites[nsprites].name, "sprite-%d", nsprites+1);
+
+               /* Allocate a buffer for the sprite and calculate the buffer
+                * size:
+                */
+               buf_size = sizeof (png_uint_16 [4]);
+               buf_size *= sprites[nsprites].width;
+               buf_size *= sprites[nsprites].height;
+
+               /* This can overflow a (size_t); check for this: */
+               tmp = buf_size;
+               tmp /= sprites[nsprites].width;
+               tmp /= sprites[nsprites].height;
+
+               if (tmp == sizeof (png_uint_16 [4]))
+               {
+                  sprites[nsprites].buffer = malloc(buf_size);
+                  /* This buffer must be initialized to transparent: */
+                  memset(sprites[nsprites].buffer, 0, buf_size);
+
+                  if (sprites[nsprites].buffer != NULL)
+                  {
+                     sprites[nsprites].file = NULL;
+                     ++argv, --argc;
+
+                     if (create_sprite(sprites+nsprites++, &argc, &argv))
+                     {
+                        result = 1; /* still ok */
+                        continue;
+                     }
+
+                     break; /* error */
+                  }
+               }
+
+               /* Overflow, or OOM */
+               fprintf(stderr, "simpleover: %s: sprite too large\n", argv[0]);
+               break;
+            }
+
+            else
+            {
+               fprintf(stderr, "simpleover: %s: invalid sprite (%u,%u)\n",
+                  argv[0], sprites[nsprites].width, sprites[nsprites].height);
+               break;
+            }
+         }
+
+         else
+         {
+            fprintf(stderr, "simpleover: %s: too many sprites\n", argv[0]);
+            break;
+         }
+      }
+
+      else if (strncmp(argv[0], "--add=", 6) == 0)
+      {
+         const char *name = argv[0]+6;
+         int isprite = nsprites;
+
+         ++argv, --argc;
+
+         while (--isprite >= 0)
+         {
+            if (strcmp(sprites[isprite].name, name) == 0)
+            {
+               if (!add_sprite(output, out_buf, sprites+isprite, &argc, &argv))
+                  goto out; /* error in add_sprite */
+
+               break;
+            }
+         }
+
+         if (isprite < 0) /* sprite not found */
+         {
+            fprintf(stderr, "simpleover: --add='%s': sprite not found\n", name);
+            break;
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "simpleover: %s: unrecognized operation\n", argv[0]);
+         break;
+      }
+
+      result = 1; /* ok  */
+   }
+
+   /* Clean up the cache of sprites: */
+out:
+   while (--nsprites >= 0)
+   {
+      if (sprites[nsprites].buffer != NULL)
+         free(sprites[nsprites].buffer);
+
+      if (sprites[nsprites].file != NULL)
+         (void)fclose(sprites[nsprites].file);
+   }
+
+   return result;
+}
+
+int main(int argc, const char **argv)
+{
+   int result = 1; /* default to fail */
+
+   if (argc >= 2)
+   {
+      int argi = 2;
+      const char *output = NULL;
+      png_image image;
+
+      if (argc > 2 && argv[2][0] != '-'/*an operation*/)
+      {
+         output = argv[2];
+         argi = 3;
+      }
+
+      image.version = PNG_IMAGE_VERSION;
+      image.opaque = NULL;
+
+      if (png_image_begin_read_from_file(&image, argv[1]))
+      {
+         png_bytep buffer;
+
+         image.format = PNG_FORMAT_RGB; /* 24-bit RGB */
+
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         if (buffer != NULL)
+         {
+            png_color background = {0, 0xff, 0}; /* fully saturated green */
+
+            if (png_image_finish_read(&image, &background, buffer,
+               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
+            {
+               /* At this point png_image_finish_read has cleaned up the
+                * allocated data in png_image, and only the buffer needs to be
+                * freed.
+                *
+                * Perform the remaining operations:
+                */
+               if (simpleover_process(&image, buffer, argc-argi, argv+argi))
+               {
+                  /* Write the output: */
+                  if ((output != NULL &&
+                       png_image_write_to_file(&image, output,
+                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                        NULL/*colormap*/)) ||
+                      (output == NULL &&
+                       png_image_write_to_stdio(&image, stdout,
+                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
+                        NULL/*colormap*/)))
+                     result = 0;
+
+                  else
+                     fprintf(stderr, "simpleover: write %s: %s\n",
+                        output == NULL ? "stdout" : output, image.message);
+               }
+
+               /* else simpleover_process writes an error message */
+            }
+
+            else
+               fprintf(stderr, "simpleover: read %s: %s\n", argv[1],
+                   image.message);
+
+            free(buffer);
+         }
+
+         else
+         {
+            fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+
+            /* This is the only place where a 'free' is required; libpng does
+             * the cleanup on error and success, but in this case we couldn't
+             * complete the read because of running out of memory.
+             */
+            png_image_free(&image);
+         }
+      }
+
+      else
+      {
+         /* Failed to read the first argument: */
+         fprintf(stderr, "simpleover: %s: %s\n", argv[1], image.message);
+      }
+   }
+
+   else
+   {
+      /* Usage message */
+      fprintf(stderr,
+         "simpleover: usage: simpleover background.png [output.png]\n"
+         "  Output 'background.png' as a 24-bit RGB PNG file in 'output.png'\n"
+         "   or, if not given, stdout.  'background.png' will be composited\n"
+         "   on fully saturated green.\n"
+         "\n"
+         "  Optionally, before output, process additional PNG files:\n"
+         "\n"
+         "   --sprite=width,height,name {[--at=x,y] {sprite.png}}\n"
+         "    Produce a transparent sprite of size (width,height) and with\n"
+         "     name 'name'.\n"
+         "    For each sprite.png composite it using a Porter-Duff 'Over'\n"
+         "     operation at offset (x,y) in the sprite (defaulting to (0,0)).\n"
+         "     Input PNGs will be truncated to the area of the sprite.\n"
+         "\n"
+         "   --add='name' {x,y}\n"
+         "    Optionally, before output, composite a sprite, 'name', which\n"
+         "     must have been previously produced using --sprite, at each\n"
+         "     offset (x,y) in the output image.  Each sprite must fit\n"
+         "     completely within the output image.\n"
+         "\n"
+         "  PNG files are processed in the order they occur on the command\n"
+         "  line and thus the first PNG processed appears as the bottommost\n"
+         "  in the output image.\n");
+   }
+
+   return result;
+}
+#endif /* SIMPLIFIED_READ */
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/COPYING
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/COPYING	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/COPYING	(revision 107811)
@@ -0,0 +1,345 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
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+
+This section is intended to make thoroughly clear what is believed to
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+
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+be similar in spirit to the present version, but may differ in detail to
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+
+Each version is given a distinguishing version number.  If the Program
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+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
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+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
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+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
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+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
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+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+                     END OF TERMS AND CONDITIONS
+
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
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+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
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+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Library General
+Public License instead of this License.
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/LICENSE
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/LICENSE	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/LICENSE	(revision 107811)
@@ -0,0 +1,50 @@
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.mingw32
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.mingw32	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.mingw32	(revision 107811)
@@ -0,0 +1,131 @@
+# Sample makefile for rpng-win / rpng2-win / wpng using mingw32-gcc and make.
+# Greg Roelofs
+# Last modified:  2 June 2007
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
+#	generally for sale anymore, but it's the thought that counts,
+#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
+#
+# Invoke this makefile from a DOS-prompt window via:
+#
+#	make -f Makefile.mingw32
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are in subdirectories at the same level as the current subdirectory
+# (as indicated by the PNGDIR and ZDIR macros below).  It makes no assumptions
+# at all about the mingw32 installation tree (W32DIR).  Edit as appropriate.
+#
+# Note that the names of the dynamic and static libpng and zlib libraries
+# used below may change in later releases of the libraries.  This makefile
+# builds both statically and dynamically linked executables by default.
+# (You need only one set, but for testing it can be handy to have both.)
+
+
+# macros --------------------------------------------------------------------
+
+#PNGDIR = ../..#		for libpng-x.y.z/contrib/gregbook builds
+PNGDIR = ../libpng-win32
+PNGINC = -I$(PNGDIR)
+PNGLIBd = $(PNGDIR)/libpng.dll.a	# dynamically linked
+PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
+
+#ZDIR = ../../../zlib-win32#	for libpng-x.y.z/contrib/gregbook builds
+ZDIR = ../zlib-win32
+ZINC = -I$(ZDIR)
+ZLIBd = $(ZDIR)/libzdll.a
+ZLIBs = $(ZDIR)/libz.a
+
+# change this to be the path where mingw32 installs its stuff:
+W32DIR =
+#W32DIR = /usr/local/cross-tools/i386-mingw32msvc
+W32INC = -I$(W32DIR)/include
+W32LIB = $(W32DIR)/lib/libuser32.a $(W32DIR)/lib/libgdi32.a
+
+CC = gcc
+#CC = i386-mingw32msvc-gcc #	e.g., Linux -> Win32 cross-compilation
+LD = $(CC)
+RM = rm -f
+CPPFLAGS = $(INCS)
+CFLAGS = -O -Wall $(MINGW_CCFLAGS)
+# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
+# [-ansi, -pedantic and -W can also be used]
+LDFLAGS = $(MINGW_LDFLAGS)
+O = .o
+E = .exe
+
+INCS = $(PNGINC) $(ZINC) $(W32INC)
+RLIBSd = $(PNGLIBd) $(ZLIBd) $(W32LIB) -lm
+RLIBSs = $(PNGLIBs) $(ZLIBs) $(W32LIB) -lm
+WLIBSd = $(PNGLIBd) $(ZLIBd)
+WLIBSs = $(PNGLIBs) $(ZLIBs)
+
+RPNG   = rpng-win
+RPNG2  = rpng2-win
+WPNG   = wpng
+
+ROBJSd  = $(RPNG)$(O) readpng.pic$(O)
+ROBJS2d = $(RPNG2)$(O) readpng2.pic$(O)
+WOBJSd  = $(WPNG)$(O) writepng.pic$(O)
+
+RPNGs  = $(RPNG)-static
+RPNG2s = $(RPNG2)-static
+WPNGs  = $(WPNG)-static
+
+ROBJSs  = $(RPNG)$(O) readpng$(O)
+ROBJS2s = $(RPNG2)$(O) readpng2$(O)
+WOBJSs  = $(WPNG)$(O) writepng$(O)
+
+STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
+DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+%.pic$(O): %.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -DPNG_BUILD_DLL -o $@ $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNGs)$(E): $(ROBJSs)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJSs) $(RLIBSs)
+
+$(RPNG)$(E): $(ROBJSd)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJSd) $(RLIBSd)
+
+$(RPNG2s)$(E): $(ROBJS2s)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2s) $(RLIBSs)
+
+$(RPNG2)$(E): $(ROBJS2d)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2d) $(RLIBSd)
+
+$(WPNGs)$(E): $(WOBJSs)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJSs) $(WLIBSs)
+
+$(WPNG)$(E): $(WOBJSd)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJSd) $(WLIBSd)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O) readpng.pic$(O):	readpng.c readpng.h
+readpng2$(O) readpng2.pic$(O):	readpng2.c readpng2.h
+writepng$(O) writepng.pic$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+	$(RM) $(EXES)
+	$(RM) $(ROBJSs) $(ROBJS2s) $(WOBJSs)
+	$(RM) $(ROBJSd) $(ROBJS2d) $(WOBJSd)
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.sgi
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.sgi	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.sgi	(revision 107811)
@@ -0,0 +1,105 @@
+# Sample makefile for rpng-x / rpng2-x / wpng for SGI using cc and make.
+# Greg Roelofs
+# Last modified:  7 March 2002
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Buy some for friends
+#	and family, too.  (Not that this is a blatant plug or anything.)
+#
+# Invoke this makefile from a shell prompt in the usual way; for example:
+#
+#	make -f Makefile.sgi
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are both installed in /usr/local/{include,lib} (as indicated by the
+# PNG* and Z* macros below).  Edit as appropriate--choose only ONE each of
+# the PNGINC, PNGLIB, ZINC and ZLIB lines.
+#
+# This makefile builds dynamically linked executables (against libpng and zlib,
+# that is), but that can be changed by uncommenting the appropriate PNGLIB and
+# ZLIB lines.
+
+
+# macros --------------------------------------------------------------------
+
+PNGINC = -I/usr/local/include/libpng16
+PNGLIB = -L/usr/local/lib -lpng16	  # dynamically linked against libpng
+#PNGLIB = /usr/local/lib/libpng16.a # statically linked against libpng
+# or:
+#PNGINC = -I../..
+#PNGLIB = -L../.. -lpng
+#PNGLIB = ../../libpng.a
+
+ZINC = -I/usr/local/include
+ZLIB = -L/usr/local/lib -lz		# dynamically linked against zlib
+#ZLIB = /usr/local/lib/libz.a		# statically linked against zlib
+#ZINC = -I../zlib
+#ZLIB = -L../zlib -lz
+#ZLIB = ../../../zlib/libz.a
+
+XINC = -I/usr/include/X11		# old-style, stock X distributions
+XLIB = -L/usr/lib/X11 -lX11
+#XINC = -I/usr/openwin/include    	# Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+#XINC = -I/usr/X11R6/include		# new X distributions (XFree86, etc.)
+#XLIB = -L/usr/X11R6/lib -lX11
+
+INCS = $(PNGINC) $(ZINC) $(XINC)
+RLIBS = $(PNGLIB) $(ZLIB) $(XLIB) -lm
+WLIBS = $(PNGLIB) $(ZLIB)
+
+CC = cc
+LD = cc
+RM = rm -f
+# ABI must be the same as that used to build libpng.
+ABI =
+CPPFLAGS =
+CFLAGS = $(ABI) -O -fullwarn $(INCS)
+LDFLAGS = $(ABI)
+O = .o
+E =
+
+RPNG  = rpng-x
+RPNG2 = rpng2-x
+WPNG  = wpng
+
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+
+EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNG)$(E): $(ROBJS)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBS)
+
+$(RPNG2)$(E): $(ROBJS2)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBS)
+
+$(WPNG)$(E): $(WOBJS)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBS)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O):	readpng.c readpng.h
+readpng2$(O):	readpng2.c readpng2.h
+writepng$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.unx
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.unx	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.unx	(revision 107811)
@@ -0,0 +1,134 @@
+# Sample makefile for rpng-x / rpng2-x / wpng using gcc and make.
+# Greg Roelofs
+# Last modified:  2 June 2007
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
+#	generally for sale anymore, but it's the thought that counts,
+#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
+#
+# Invoke this makefile from a shell prompt in the usual way; for example:
+#
+#	make -f Makefile.unx
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are installed in /usr/local/{include,lib} or as otherwise indicated by
+# the PNG* and Z* macros below.  Edit as appropriate--choose only ONE each of
+# the PNGINC, PNGLIBd, PNGLIBs, ZINC, ZLIBd and ZLIBs lines.
+#
+# This makefile builds both dynamically and statically linked executables
+# (against libpng and zlib, that is), but that can be changed by modifying
+# the "EXES =" line.  (You need only one set, but for testing it can be handy
+# to have both.)
+
+
+# macros --------------------------------------------------------------------
+
+#PNGDIR = /usr/local/lib
+#PNGINC = -I/usr/local/include/libpng16
+#PNGLIBd = -L$(PNGDIR) -lpng16 # dynamically linked, installed libpng
+#PNGLIBs = $(PNGDIR)/libpng16.a # statically linked, installed libpng
+# or:
+PNGDIR = ../..#	this one is for libpng-x.y.z/contrib/gregbook builds
+#PNGDIR = ../libpng
+PNGINC = -I$(PNGDIR)
+PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng16	# dynamically linked
+PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
+
+ZDIR = /usr/local/lib
+#ZDIR = /usr/lib64
+ZINC = -I/usr/local/include
+ZLIBd = -L$(ZDIR) -lz			# dynamically linked against zlib
+ZLIBs = $(ZDIR)/libz.a			# statically linked against zlib
+# or:
+#ZDIR = ../zlib
+#ZINC = -I$(ZDIR)
+#ZLIBd = -Wl,-rpath,$(ZDIR) -L$(ZDIR) -lz  # -rpath allows in-place testing
+#ZLIBs = $(ZDIR)/libz.a
+
+#XINC = -I/usr/include			# old-style, stock X distributions
+#XLIB = -L/usr/lib/X11 -lX11		#  (including SGI IRIX)
+#XINC = -I/usr/openwin/include		# Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+XINC = -I/usr/X11R6/include		# new X distributions (X.org, etc.)
+XLIB = -L/usr/X11R6/lib -lX11
+#XLIB = -L/usr/X11R6/lib64 -lX11	# e.g., Red Hat on AMD64
+
+INCS = $(PNGINC) $(ZINC) $(XINC)
+RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
+RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
+WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
+WLIBSs = $(PNGLIBs) $(ZLIBs) -lm
+
+CC = gcc
+LD = gcc
+RM = rm -f
+CPPFLAGS = $(INCS) -DFEATURE_LOOP
+CFLAGS = -O -Wall
+#CFLAGS = -O -W -Wall -Wextra -pedantic -ansi
+# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
+# [-ansi, -pedantic, -Wextra, and -W can also be used]
+LDFLAGS =
+O = .o
+E =
+
+RPNG   = rpng-x
+RPNG2  = rpng2-x
+WPNG   = wpng
+
+RPNGs  = $(RPNG)-static
+RPNG2s = $(RPNG2)-static
+WPNGs  = $(WPNG)-static
+
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+
+STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
+DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNGs)$(E): $(ROBJS)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSs)
+
+$(RPNG)$(E): $(ROBJS)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSd)
+
+$(RPNG2s)$(E): $(ROBJS2)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSs)
+
+$(RPNG2)$(E): $(ROBJS2)
+	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSd)
+
+$(WPNGs)$(E): $(WOBJS)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSs)
+
+$(WPNG)$(E): $(WOBJS)
+	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSd)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O):	readpng.c readpng.h
+readpng2$(O):	readpng2.c readpng2.h
+writepng$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.w32
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.w32	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/Makefile.w32	(revision 107811)
@@ -0,0 +1,114 @@
+# Sample makefile for rpng-win / rpng2-win / wpng using MSVC and NMAKE.
+# Greg Roelofs
+# Last modified:  2 June 2007
+#
+#	The programs built by this makefile are described in the book,
+#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
+#	generally for sale anymore, but it's the thought that counts,
+#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
+#
+# Invoke this makefile from a DOS prompt window via:
+#
+#	%devstudio%\vc\bin\vcvars32.bat
+#	nmake -nologo -f Makefile.w32
+#
+# where %devstudio% is the installation directory for MSVC / DevStudio.  If
+# you get "environment out of space" errors, create a desktop shortcut with
+# "c:\windows\command.com /e:4096" as the program command line and set the
+# working directory to this directory.  Then double-click to open the new
+# DOS-prompt window with a bigger environment and retry the commands above.
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are in subdirectories at the same level as the current subdirectory
+# (as indicated by the PNGPATH and ZPATH macros below).  Edit as appropriate.
+#
+# Note that the names of the dynamic and static libpng and zlib libraries
+# used below may change in later releases of the libraries.  This makefile
+# builds statically linked executables, but that can be changed by uncom-
+# menting the appropriate PNGLIB and ZLIB lines.
+
+!include <ntwin32.mak>
+
+
+# macros --------------------------------------------------------------------
+
+PNGPATH = ../libpng
+PNGINC = -I$(PNGPATH)
+#PNGLIB = $(PNGPATH)/pngdll.lib
+PNGLIB = $(PNGPATH)/libpng.lib
+
+ZPATH = ../zlib
+ZINC = -I$(ZPATH)
+#ZLIB = $(ZPATH)/zlibdll.lib
+ZLIB = $(ZPATH)/zlibstat.lib
+
+WINLIBS = -defaultlib:user32.lib gdi32.lib
+# ["real" apps may also need comctl32.lib, comdlg32.lib, winmm.lib, etc.]
+
+INCS = $(PNGINC) $(ZINC)
+RLIBS = $(PNGLIB) $(ZLIB) $(WINLIBS)
+WLIBS = $(PNGLIB) $(ZLIB)
+
+CC = cl
+LD = link
+RM = del
+CPPFLAGS = $(INCS)
+CFLAGS = -nologo -O -W3 $(cvars)
+# [note that -W3 is an MSVC-specific compilation flag ("all warnings on")]
+# [see %devstudio%\vc\include\win32.mak for cvars macro definition]
+O = .obj
+E = .exe
+
+RLDFLAGS = -nologo -subsystem:windows
+WLDFLAGS = -nologo
+
+RPNG  = rpng-win
+RPNG2 = rpng2-win
+WPNG  = wpng
+
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+
+EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+
+# dependencies --------------------------------------------------------------
+
+all:  $(EXES)
+
+$(RPNG)$(E): $(ROBJS)
+	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS) $(RLIBS)
+
+$(RPNG2)$(E): $(ROBJS2)
+	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS2) $(RLIBS)
+
+$(WPNG)$(E): $(WOBJS)
+	$(LD) $(WLDFLAGS) -out:$@ $(WOBJS) $(WLIBS)
+
+$(RPNG)$(O):	$(RPNG).c readpng.h
+$(RPNG2)$(O):	$(RPNG2).c readpng2.h
+$(WPNG)$(O):	$(WPNG).c writepng.h
+
+readpng$(O):	readpng.c readpng.h
+readpng2$(O):	readpng2.c readpng2.h
+writepng$(O):	writepng.c writepng.h
+
+
+# maintenance ---------------------------------------------------------------
+
+clean:
+#	ideally we could just do this:
+#	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
+#	...but the Windows "DEL" command is none too bright, so:
+	$(RM) r*$(E)
+	$(RM) w*$(E)
+	$(RM) r*$(O)
+	$(RM) w*$(O)
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/README	(revision 107811)
@@ -0,0 +1,186 @@
+                     ===========================
+                      PNG: The Definitive Guide
+                     ===========================
+
+                             Source Code
+
+Chapters 13, 14 and 15 of "PNG: The Definitive Guide" discuss three free,
+cross-platform demo programs that show how to use the libpng reference
+library:  rpng, rpng2 and wpng.  rpng and rpng2 are viewers; the first is
+a very simple example that that shows how a standard file-viewer might use
+libpng, while the second is designed to process streaming data and shows
+how a web browser might be written.  wpng is a simple command-line program
+that reads binary PGM and PPM files (the ``raw'' grayscale and RGB subsets
+of PBMPLUS/NetPBM) and converts them to PNG.
+
+The source code for all three demo programs currently compiles under
+Unix, OpenVMS, and 32-bit Windows.  (Special thanks to Martin Zinser,
+zinser at decus.de, for making the necessary changes for OpenVMS and for
+providing an appropriate build script.)  Build instructions can be found
+below.
+
+Files:
+
+   README             this file
+   LICENSE            terms of distribution and reuse (BSD-like or GNU GPL)
+   COPYING            GNU General Public License (GPL)
+
+   Makefile.unx       Unix makefile
+   Makefile.w32       Windows (MSVC) makefile
+   makevms.com        OpenVMS build script
+
+   rpng-win.c         Windows front end for the basic viewer
+   rpng-x.c           X Window System (Unix, OpenVMS) front end
+   readpng.c          generic back end for the basic viewer
+   readpng.h          header file for the basic viewer
+
+   rpng2-win.c        Windows front end for the progressive viewer
+   rpng2-x.c          X front end for the progressive viewer
+   readpng2.c         generic back end for the progressive viewer
+   readpng2.h         header file for the progressive viewer
+
+   wpng.c             generic (text) front end for the converter
+   writepng.c         generic back end for the converter
+   writepng.h         header file for the converter
+
+   toucan.png         transparent PNG for testing (by Stefan Schneider)
+
+Note that, although the programs are designed to be functional, their
+primary purpose is to illustrate how to use libpng to add PNG support to
+other programs.  As such, their user interfaces are crude and definitely
+are not intended for everyday use.
+
+Please see http://www.libpng.org/pub/png/pngbook.html for further infor-
+mation and links to the latest version of the source code, and Chapters
+13-15 of the book for detailed discussion of the three programs.
+
+Greg Roelofs
+https://pobox.com/~newt/greg_contact.html
+16 March 2008
+
+
+BUILD INSTRUCTIONS
+
+ - Prerequisites (in order of compilation):
+
+      - zlib            https://zlib.net/
+      - libpng          http://www.libpng.org/pub/png/libpng.html
+      - pngbook         http://www.libpng.org/pub/png/book/sources.html
+
+     The pngbook demo programs are explicitly designed to demonstrate proper
+     coding techniques for using the libpng reference library.  As a result,
+     you need to download and build both zlib (on which libpng depends) and
+     libpng.  A common build setup is to place the zlib, libpng and pngbook
+     subdirectory trees ("folders") in the same parent directory.  Then the
+     libpng build can refer to files in ../zlib (or ..\zlib or [-.zlib]),
+     and similarly for the pngbook build.
+
+     Note that all three packages are designed to be built from a command
+     line by default; those who wish to use a graphical or other integrated
+     development environments are on their own.
+
+
+ - Unix:
+
+     Unpack the latest pngbook sources (which should correspond to this
+     README file) into a directory and change into that directory.
+
+     Copy Makefile.unx to Makefile and edit the PNG* and Z* variables
+     appropriately (possibly also the X* variables if necessary).
+
+     make
+
+     There is no "install" target, so copy the three executables somewhere
+     in your path or run them from the current directory.  All three will
+     print a basic usage screen when run without any command-line arguments;
+     see the book for more details.
+
+
+ - Windows:
+
+     Unpack the latest pngbook sources (which should correspond to this
+     README file) into a folder, open a "DOS shell" or "command prompt"
+     or equivalent command-line window, and cd into the folder where you
+     unpacked the source code.
+
+     For MSVC, set up the necessary environment variables by invoking
+
+        %devstudio%\vc\bin\vcvars32.bat
+
+     where where %devstudio% is the installation directory for MSVC /
+     DevStudio.  If you get "environment out of space" errors under 95/98,
+     create a desktop shortcut with "c:\windows\command.com /e:4096" as
+     the program command line and set the working directory to the pngbook
+     directory.  Then double-click to open the new DOS-prompt window with
+     a bigger environment and retry the commands above.
+
+     Copy Makefile.w32 to Makefile and edit the PNGPATH and ZPATH variables
+     appropriately (possibly also the "INC" and "LIB" variables if needed).
+     Note that the names of the dynamic and static libpng and zlib libraries
+     used in the makefile may change in later releases of the libraries.
+     Also note that, as of libpng version 1.0.5, MSVC DLL builds do not work.
+     This makefile therefore builds statically linked executables, but if
+     the DLL problems ever get fixed, uncommenting the appropriate PNGLIB
+     and ZLIB lines will build dynamically linked executables instead.
+
+     Do the build by typing
+
+        nmake
+
+     The result should be three executables:  rpng-win.exe, rpng2-win.exe,
+     and wpng.exe.  Copy them somewhere in your PATH or run them from the
+     current folder.  Like the Unix versions, the two windowed programs
+     (rpng and rpng2) now display a usage screen in a console window when
+     invoked without command-line arguments; this is new behavior as of
+     the June 2001 release.  Note that the programs use the Unix-style "-"
+     character to specify options, instead of the more common DOS/Windows
+     "/" character.  (For example:  "rpng2-win -bgpat 4 foo.png", not
+     "rpng2-win /bgpat 4 foo.png")
+
+
+ - OpenVMS:
+
+     Unpack the pngbook sources into a subdirectory and change into that
+     subdirectory.
+
+     Edit makevms.com appropriately, specifically the zpath and pngpath
+     variables.
+
+     @makevms
+
+     To run the programs, they probably first need to be set up as "foreign
+     symbols," with "disk" and "dir" set appropriately:
+
+     $ rpng  == "$disk:[dir]rpng-x.exe"
+     $ rpng2 == "$disk:[dir]rpng2-x.exe"
+     $ wpng  == "$disk:[dir]wpng.exe"
+
+     All three will print a basic usage screen when run without any command-
+     line arguments; see the book for more details.  Note that the options
+     style is Unix-like, i.e., preceded by "-" rather than "/".
+
+
+RUNNING THE PROGRAMS:  (VERY) BRIEF INTRO
+
+     rpng is a simple PNG viewer that can display transparent PNGs with a
+     specified background color; for example,
+
+        rpng -bgcolor \#ff0000 toucan.png
+
+     would display the image with a red background.  rpng2 is a progressive
+     viewer that simulates a web browser in some respects; it can display
+     images against either a background color or a dynamically generated
+     background image.  For example:
+
+        rpng2 -bgpat 16 toucan.png
+
+     wpng is a purely command-line image converter from binary PBMPLUS/NetPBM
+     format (.pgm or .ppm) to PNG; for example,
+
+        wpng -time < toucan-notrans.ppm > toucan-notrans.png
+
+     would convert the specified PPM file (using redirection) to PNG, auto-
+     matically setting the PNG modification-time chunk.
+
+     All options can be abbreviated to the shortest unique value; for example,
+     "-bgc" for -bgcolor (versus "-bgp" for -bgpat), or "-g" for -gamma.
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/makevms.com
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/makevms.com	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/makevms.com	(revision 107811)
@@ -0,0 +1,132 @@
+$!------------------------------------------------------------------------------
+$! make "PNG: The Definitive Guide" demo programs (for X) under OpenVMS
+$!
+$! Script created by Martin Zinser for libpng; modified by Greg Roelofs
+$! for standalone pngbook source distribution.
+$!
+$!
+$!    Set locations where zlib and libpng sources live.
+$!
+$ zpath   = ""
+$ pngpath = ""
+$!
+$ if f$search("[---.zlib]zlib.h").nes."" then zpath = "[---.zlib]"
+$ if f$search("[--]png.h").nes."" then pngpath = "[--]"
+$!
+$ if f$search("[-.zlib]zlib.h").nes."" then zpath = "[-.zlib]"
+$ if f$search("[-.libpng]png.h").nes."" then pngpath = "[-.libpng]"
+$!
+$ if zpath .eqs. ""
+$ then
+$   write sys$output "zlib include not found. Exiting..."
+$   exit 2
+$ endif
+$!
+$ if pngpath .eqs. ""
+$ then
+$   write sys$output "libpng include not found. Exiting..."
+$   exit 2
+$ endif
+$!
+$!    Look for the compiler used.
+$!
+$ ccopt="/include=(''zpath',''pngpath')"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$ open/write lopt lib.opt
+$ write lopt "''pngpath'libpng.olb/lib"
+$ write lopt "''zpath'libz.olb/lib"
+$ close lopt
+$ open/write xopt x11.opt
+$ write xopt "sys$library:decw$xlibshr.exe/share"
+$ close xopt
+$!
+$!    Build 'em.
+$!
+$ write sys$output "Compiling PNG book programs ..."
+$   CALL MAKE readpng.OBJ "cc ''CCOPT' readpng" -
+	readpng.c readpng.h
+$   CALL MAKE readpng2.OBJ "cc ''CCOPT' readpng2" -
+	readpng2.c readpng2.h
+$   CALL MAKE writepng.OBJ "cc ''CCOPT' writepng" -
+	writepng.c writepng.h
+$   write sys$output "Building rpng-x..."
+$   CALL MAKE rpng-x.OBJ "cc ''CCOPT' rpng-x" -
+	rpng-x.c readpng.h
+$   call make rpng-x.exe -
+	"LINK rpng-x,readpng,lib.opt/opt,x11.opt/opt" -
+	rpng-x.obj readpng.obj
+$   write sys$output "Building rpng2-x..."
+$   CALL MAKE rpng2-x.OBJ "cc ''CCOPT' rpng2-x" -
+	rpng2-x.c readpng2.h
+$   call make rpng2-x.exe -
+	"LINK rpng2-x,readpng2,lib.opt/opt,x11.opt/opt" -
+	rpng2-x.obj readpng2.obj
+$   write sys$output "Building wpng..."
+$   CALL MAKE wpng.OBJ "cc ''CCOPT' wpng" -
+	wpng.c writepng.h
+$   call make wpng.exe -
+	"LINK wpng,writepng,lib.opt/opt" -
+	wpng.obj writepng.obj
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng.c	(revision 107811)
@@ -0,0 +1,323 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                              readpng.c
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007,2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <zlib.h>
+
+#include "png.h"        /* libpng header */
+#include "readpng.h"    /* typedefs, common macros, public prototypes */
+
+/* future versions of libpng will provide this macro: */
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr)   ((png_ptr)->jmpbuf)
+#endif
+
+
+static png_structp png_ptr = NULL;
+static png_infop info_ptr = NULL;
+
+png_uint_32  width, height;
+int  bit_depth, color_type;
+uch  *image_data = NULL;
+
+
+void readpng_version_info(void)
+{
+    fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
+      PNG_LIBPNG_VER_STRING, png_libpng_ver);
+    fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
+      ZLIB_VERSION, zlib_version);
+}
+
+
+/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
+
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
+{
+    uch sig[8];
+
+
+    /* first do a quick check that the file really is a PNG image; could
+     * have used slightly more general png_sig_cmp() function instead */
+
+    fread(sig, 1, 8, infile);
+    if (png_sig_cmp(sig, 0, 8))
+        return 1;   /* bad signature */
+
+
+    /* could pass pointers to user-defined error handlers instead of NULLs: */
+
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), NULL, NULL,
+        NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        return 4;   /* out of memory */
+    }
+
+
+    /* we could create a second info struct here (end_info), but it's only
+     * useful if we want to keep pre- and post-IDAT chunk info separated
+     * (mainly for PNG-aware image editors and converters) */
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+
+
+    png_init_io(png_ptr, infile);
+    png_set_sig_bytes(png_ptr, 8);  /* we already read the 8 signature bytes */
+
+    png_read_info(png_ptr, info_ptr);  /* read all PNG info up to image data */
+
+
+    /* alternatively, could make separate calls to png_get_image_width(),
+     * etc., but want bit_depth and color_type for later [don't care about
+     * compression_type and filter_type => NULLs] */
+
+    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+      NULL, NULL, NULL);
+    *pWidth = width;
+    *pHeight = height;
+
+
+    /* OK, that's all we need for now; return happy */
+
+    return 0;
+}
+
+
+
+
+/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
+ * scales values to 8-bit if necessary */
+
+int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
+{
+    png_color_16p pBackground;
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+
+
+    if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
+        return 1;
+
+    /* it is not obvious from the libpng documentation, but this function
+     * takes a pointer to a pointer, and it always returns valid red, green
+     * and blue values, regardless of color_type: */
+
+    png_get_bKGD(png_ptr, info_ptr, &pBackground);
+
+
+    /* however, it always returns the raw bKGD data, regardless of any
+     * bit-depth transformations, so check depth and adjust if necessary */
+
+    if (bit_depth == 16) {
+        *red   = pBackground->red   >> 8;
+        *green = pBackground->green >> 8;
+        *blue  = pBackground->blue  >> 8;
+    } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
+        if (bit_depth == 1)
+            *red = *green = *blue = pBackground->gray? 255 : 0;
+        else if (bit_depth == 2)
+            *red = *green = *blue = (255/3) * pBackground->gray;
+        else /* bit_depth == 4 */
+            *red = *green = *blue = (255/15) * pBackground->gray;
+    } else {
+        *red   = (uch)pBackground->red;
+        *green = (uch)pBackground->green;
+        *blue  = (uch)pBackground->blue;
+    }
+
+    return 0;
+}
+
+
+
+
+/* display_exponent == LUT_exponent * CRT_exponent */
+
+uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
+{
+    double  gamma;
+    png_uint_32  i, rowbytes;
+    png_bytepp  row_pointers = NULL;
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        free(image_data);
+        image_data = NULL;
+        free(row_pointers);
+        row_pointers = NULL;
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return NULL;
+    }
+
+
+    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
+     * transparency chunks to full alpha channel; strip 16-bit-per-sample
+     * images to 8 bits per sample; and convert grayscale to RGB[A] */
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_expand(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+        png_set_expand(png_ptr);
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+        png_set_expand(png_ptr);
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+    if (bit_depth == 16)
+#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+        png_set_scale_16(png_ptr);
+#  else
+        png_set_strip_16(png_ptr);
+#  endif
+#endif
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+        png_set_gray_to_rgb(png_ptr);
+
+
+    /* unlike the example in the libpng documentation, we have *no* idea where
+     * this file may have come from--so if it doesn't have a file gamma, don't
+     * do any correction ("do no harm") */
+
+    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
+        png_set_gamma(png_ptr, display_exponent, gamma);
+
+
+    /* all transformations have been registered; now update info_ptr data,
+     * get rowbytes and channels, and allocate image memory */
+
+    png_read_update_info(png_ptr, info_ptr);
+
+    *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+    *pChannels = (int)png_get_channels(png_ptr, info_ptr);
+
+    /* Guard against integer overflow */
+    if (height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, "readpng:  image_data buffer would be too large\n",
+        return NULL;
+    }
+
+    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return NULL;
+    }
+    if ((row_pointers = (png_bytepp)malloc(height*sizeof(png_bytep))) == NULL) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        free(image_data);
+        image_data = NULL;
+        return NULL;
+    }
+
+    Trace((stderr, "readpng_get_image:  channels = %d, rowbytes = %ld, height = %ld\n",
+        *pChannels, rowbytes, height));
+
+
+    /* set the individual row_pointers to point at the correct offsets */
+
+    for (i = 0;  i < height;  ++i)
+        row_pointers[i] = image_data + i*rowbytes;
+
+
+    /* now we can go ahead and just read the whole image */
+
+    png_read_image(png_ptr, row_pointers);
+
+
+    /* and we're done!  (png_read_end() can be omitted if no processing of
+     * post-IDAT text/time/etc. is desired) */
+
+    free(row_pointers);
+    row_pointers = NULL;
+
+    png_read_end(png_ptr, NULL);
+
+    return image_data;
+}
+
+
+void readpng_cleanup(int free_image_data)
+{
+    if (free_image_data && image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+
+    if (png_ptr && info_ptr) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        png_ptr = NULL;
+        info_ptr = NULL;
+    }
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng.h	(revision 107811)
@@ -0,0 +1,88 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                              readpng.h
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+
+
+/* prototypes for public functions in readpng.c */
+
+void readpng_version_info(void);
+
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight);
+
+int readpng_get_bgcolor(uch *bg_red, uch *bg_green, uch *bg_blue);
+
+uch *readpng_get_image(double display_exponent, int *pChannels,
+                       ulg *pRowbytes);
+
+void readpng_cleanup(int free_image_data);
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng2.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng2.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng2.c	(revision 107811)
@@ -0,0 +1,521 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                 readpng2.c
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2015 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+     2015-11-12 - Check return value of png_get_bKGD() (Glenn R-P)
+     2017-04-22 - Guard against integer overflow (Glenn R-P)
+
+  ---------------------------------------------------------------------------*/
+
+
+#include <stdlib.h>     /* for exit() prototype */
+#include <setjmp.h>
+
+#include <zlib.h>
+#include "png.h"        /* libpng header from the local directory */
+#include "readpng2.h"   /* typedefs, common macros, public prototypes */
+
+
+/* local prototypes */
+
+static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr);
+static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
+                                 png_uint_32 row_num, int pass);
+static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr);
+static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg);
+static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg);
+
+
+
+
+void readpng2_version_info(void)
+{
+    fprintf(stderr, "   Compiled with libpng %s; using libpng %s\n",
+      PNG_LIBPNG_VER_STRING, png_libpng_ver);
+
+    fprintf(stderr, "   and with zlib %s; using zlib %s.\n",
+      ZLIB_VERSION, zlib_version);
+}
+
+
+
+
+int readpng2_check_sig(uch *sig, int num)
+{
+    return !png_sig_cmp(sig, 0, num);
+}
+
+
+
+
+/* returns 0 for success, 2 for libpng problem, 4 for out of memory */
+
+int readpng2_init(mainprog_info *mainprog_ptr)
+{
+    png_structp  png_ptr;       /* note:  temporary variables! */
+    png_infop  info_ptr;
+
+
+    /* could also replace libpng warning-handler (final NULL), but no need: */
+
+    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), mainprog_ptr,
+      readpng2_error_handler, readpng2_warning_handler);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        return 4;   /* out of memory */
+    }
+
+
+    /* we could create a second info struct here (end_info), but it's only
+     * useful if we want to keep pre- and post-IDAT chunk info separated
+     * (mainly for PNG-aware image editors and converters) */
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function, unless an alternate error handler was installed--
+     * but compatible error handlers must either use longjmp() themselves
+     * (as in this program) or exit immediately, so here we are: */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+    /* prepare the reader to ignore all recognized chunks whose data won't be
+     * used, i.e., all chunks recognized by libpng except for IHDR, PLTE, IDAT,
+     * IEND, tRNS, bKGD, gAMA, and sRGB (small performance improvement) */
+    {
+        /* These byte strings were copied from png.h.  If a future version
+         * of readpng2.c recognizes more chunks, add them to this list.
+         */
+        static const png_byte chunks_to_process[] = {
+            98,  75,  71,  68, '\0',  /* bKGD */
+           103,  65,  77,  65, '\0',  /* gAMA */
+           115,  82,  71,  66, '\0',  /* sRGB */
+           };
+
+       /* Ignore all chunks except for IHDR, PLTE, tRNS, IDAT, and IEND */
+       png_set_keep_unknown_chunks(png_ptr, -1 /* PNG_HANDLE_CHUNK_NEVER */,
+          NULL, -1);
+
+       /* But do not ignore chunks in the "chunks_to_process" list */
+       png_set_keep_unknown_chunks(png_ptr,
+          0 /* PNG_HANDLE_CHUNK_AS_DEFAULT */, chunks_to_process,
+          sizeof(chunks_to_process)/5);
+    }
+#endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */
+
+
+    /* instead of doing png_init_io() here, now we set up our callback
+     * functions for progressive decoding */
+
+    png_set_progressive_read_fn(png_ptr, mainprog_ptr,
+      readpng2_info_callback, readpng2_row_callback, readpng2_end_callback);
+
+
+    /* make sure we save our pointers for use in readpng2_decode_data() */
+
+    mainprog_ptr->png_ptr = png_ptr;
+    mainprog_ptr->info_ptr = info_ptr;
+
+
+    /* and that's all there is to initialization */
+
+    return 0;
+}
+
+
+
+
+/* returns 0 for success, 2 for libpng (longjmp) problem */
+
+int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* hand off the next chunk of input data to libpng for decoding */
+
+    png_process_data(png_ptr, info_ptr, rawbuf, length);
+
+    return 0;
+}
+
+
+
+
+static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr)
+{
+    mainprog_info  *mainprog_ptr;
+    int  color_type, bit_depth;
+    png_uint_32 width, height;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+    double  gamma;
+#else
+    png_fixed_point gamma;
+#endif
+
+
+    /* setjmp() doesn't make sense here, because we'd either have to exit(),
+     * longjmp() ourselves, or return control to libpng, which doesn't want
+     * to see us again.  By not doing anything here, libpng will instead jump
+     * to readpng2_decode_data(), which can return an error value to the main
+     * program. */
+
+
+    /* retrieve the pointer to our special-purpose struct, using the png_ptr
+     * that libpng passed back to us (i.e., not a global this time--there's
+     * no real difference for a single image, but for a multithreaded browser
+     * decoding several PNG images at the same time, one needs to avoid mixing
+     * up different images' structs) */
+
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+
+    if (mainprog_ptr == NULL) {         /* we be hosed */
+        fprintf(stderr,
+          "readpng2 error:  main struct not recoverable in info_callback.\n");
+        fflush(stderr);
+        return;
+        /*
+         * Alternatively, we could call our error-handler just like libpng
+         * does, which would effectively terminate the program.  Since this
+         * can only happen if png_ptr gets redirected somewhere odd or the
+         * main PNG struct gets wiped, we're probably toast anyway.  (If
+         * png_ptr itself is NULL, we would not have been called.)
+         */
+    }
+
+
+    /* this is just like in the non-progressive case */
+
+    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+       NULL, NULL, NULL);
+    mainprog_ptr->width = (ulg)width;
+    mainprog_ptr->height = (ulg)height;
+
+
+    /* since we know we've read all of the PNG file's "header" (i.e., up
+     * to IDAT), we can check for a background color here */
+
+    if (mainprog_ptr->need_bgcolor)
+    {
+        png_color_16p pBackground;
+
+        /* it is not obvious from the libpng documentation, but this function
+         * takes a pointer to a pointer, and it always returns valid red,
+         * green and blue values, regardless of color_type: */
+        if (png_get_bKGD(png_ptr, info_ptr, &pBackground))
+        {
+
+           /* however, it always returns the raw bKGD data, regardless of any
+            * bit-depth transformations, so check depth and adjust if necessary
+            */
+           if (bit_depth == 16) {
+               mainprog_ptr->bg_red   = pBackground->red   >> 8;
+               mainprog_ptr->bg_green = pBackground->green >> 8;
+               mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
+           } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
+               if (bit_depth == 1)
+                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                     mainprog_ptr->bg_blue = pBackground->gray? 255 : 0;
+               else if (bit_depth == 2)
+                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                     mainprog_ptr->bg_blue = (255/3) * pBackground->gray;
+               else /* bit_depth == 4 */
+                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                     mainprog_ptr->bg_blue = (255/15) * pBackground->gray;
+           } else {
+               mainprog_ptr->bg_red   = (uch)pBackground->red;
+               mainprog_ptr->bg_green = (uch)pBackground->green;
+               mainprog_ptr->bg_blue  = (uch)pBackground->blue;
+           }
+        }
+    }
+
+
+    /* as before, let libpng expand palette images to RGB, low-bit-depth
+     * grayscale images to 8 bits, transparency chunks to full alpha channel;
+     * strip 16-bit-per-sample images to 8 bits per sample; and convert
+     * grayscale to RGB[A] */
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_expand(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+        png_set_expand(png_ptr);
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+        png_set_expand(png_ptr);
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+    if (bit_depth == 16)
+#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+        png_set_scale_16(png_ptr);
+#  else
+        png_set_strip_16(png_ptr);
+#  endif
+#endif
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+        png_set_gray_to_rgb(png_ptr);
+
+
+    /* Unlike the basic viewer, which was designed to operate on local files,
+     * this program is intended to simulate a web browser--even though we
+     * actually read from a local file, too.  But because we are pretending
+     * that most of the images originate on the Internet, we follow the recom-
+     * mendation of the sRGB proposal and treat unlabelled images (no gAMA
+     * chunk) as existing in the sRGB color space.  That is, we assume that
+     * such images have a file gamma of 0.45455, which corresponds to a PC-like
+     * display system.  This change in assumptions will have no effect on a
+     * PC-like system, but on a Mac, SGI, NeXT or other system with a non-
+     * identity lookup table, it will darken unlabelled images, which effec-
+     * tively favors images from PC-like systems over those originating on
+     * the local platform.  Note that mainprog_ptr->display_exponent is the
+     * "gamma" value for the entire display system, i.e., the product of
+     * LUT_exponent and CRT_exponent. */
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
+        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, gamma);
+    else
+        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, 0.45455);
+#else
+    if (png_get_gAMA_fixed(png_ptr, info_ptr, &gamma))
+        png_set_gamma_fixed(png_ptr,
+            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), gamma);
+    else
+        png_set_gamma_fixed(png_ptr,
+            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), 45455);
+#endif
+
+    /* we'll let libpng expand interlaced images, too */
+
+    mainprog_ptr->passes = png_set_interlace_handling(png_ptr);
+
+
+    /* all transformations have been registered; now update info_ptr data and
+     * then get rowbytes and channels */
+
+    png_read_update_info(png_ptr, info_ptr);
+
+    mainprog_ptr->rowbytes = (int)png_get_rowbytes(png_ptr, info_ptr);
+    mainprog_ptr->channels = png_get_channels(png_ptr, info_ptr);
+
+
+    /* Call the main program to allocate memory for the image buffer and
+     * initialize windows and whatnot.  (The old-style function-pointer
+     * invocation is used for compatibility with a few supposedly ANSI
+     * compilers that nevertheless barf on "fn_ptr()"-style syntax.) */
+
+    (*mainprog_ptr->mainprog_init)();
+
+
+    /* and that takes care of initialization */
+
+    return;
+}
+
+
+
+
+
+static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
+                                  png_uint_32 row_num, int pass)
+{
+    mainprog_info  *mainprog_ptr;
+
+
+    /* first check whether the row differs from the previous pass; if not,
+     * nothing to combine or display */
+
+    if (!new_row)
+        return;
+
+
+    /* retrieve the pointer to our special-purpose struct so we can access
+     * the old rows and image-display callback function */
+
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+
+
+    /* save the pass number for optional use by the front end */
+
+    mainprog_ptr->pass = pass;
+
+
+    /* have libpng either combine the new row data with the existing row data
+     * from previous passes (if interlaced) or else just copy the new row
+     * into the main program's image buffer */
+
+    png_progressive_combine_row(png_ptr, mainprog_ptr->row_pointers[row_num],
+      new_row);
+
+
+    /* finally, call the display routine in the main program with the number
+     * of the row we just updated */
+
+    (*mainprog_ptr->mainprog_display_row)(row_num);
+
+
+    /* and we're ready for more */
+
+    return;
+}
+
+
+
+
+
+static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)
+{
+    mainprog_info  *mainprog_ptr;
+
+
+    /* retrieve the pointer to our special-purpose struct */
+
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+
+
+    /* let the main program know that it should flush any buffered image
+     * data to the display now and set a "done" flag or whatever, but note
+     * that it SHOULD NOT DESTROY THE PNG STRUCTS YET--in other words, do
+     * NOT call readpng2_cleanup() either here or in the finish_display()
+     * routine; wait until control returns to the main program via
+     * readpng2_decode_data() */
+
+    (*mainprog_ptr->mainprog_finish_display)();
+
+
+    /* all done */
+
+    (void)info_ptr; /* Unused */
+
+    return;
+}
+
+
+
+
+
+void readpng2_cleanup(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+    if (png_ptr && info_ptr)
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+    mainprog_ptr->png_ptr = NULL;
+    mainprog_ptr->info_ptr = NULL;
+}
+
+
+static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg)
+{
+    fprintf(stderr, "readpng2 libpng warning: %s\n", msg);
+    fflush(stderr);
+    (void)png_ptr; /* Unused */
+}
+
+
+static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg)
+{
+    mainprog_info  *mainprog_ptr;
+
+    /* This function, aside from the extra step of retrieving the "error
+     * pointer" (below) and the fact that it exists within the application
+     * rather than within libpng, is essentially identical to libpng's
+     * default error handler.  The second point is critical:  since both
+     * setjmp() and longjmp() are called from the same code, they are
+     * guaranteed to have compatible notions of how big a jmp_buf is,
+     * regardless of whether _BSD_SOURCE or anything else has (or has not)
+     * been defined. */
+
+    fprintf(stderr, "readpng2 libpng error: %s\n", msg);
+    fflush(stderr);
+
+    mainprog_ptr = png_get_error_ptr(png_ptr);
+    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
+        fprintf(stderr,
+          "readpng2 severe error:  jmpbuf not recoverable; terminating.\n");
+        fflush(stderr);
+        exit(99);
+    }
+
+    /* Now we have our data structure we can use the information in it
+     * to return control to our own higher level code (all the points
+     * where 'setjmp' is called in this file.)  This will work with other
+     * error handling mechanisms as well - libpng always calls png_error
+     * when it can proceed no further, thus, so long as the error handler
+     * is intercepted, application code can do its own error recovery.
+     */
+    longjmp(mainprog_ptr->jmpbuf, 1);
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng2.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng2.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readpng2.h	(revision 107811)
@@ -0,0 +1,116 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                 readpng2.h
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+
+enum rpng2_states {
+    kPreInit = 0,
+    kWindowInit,
+    kDone
+};
+
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+
+typedef struct _mainprog_info {
+    double display_exponent;
+    ulg width;
+    ulg height;
+    void *png_ptr;
+    void *info_ptr;
+    void (*mainprog_init)(void);
+    void (*mainprog_display_row)(ulg row_num);
+    void (*mainprog_finish_display)(void);
+    uch *image_data;
+    uch **row_pointers;
+    jmp_buf jmpbuf;
+    int passes;              /* not used */
+    int pass;
+    int rowbytes;
+    int channels;
+    int need_bgcolor;
+    int state;
+    uch bg_red;
+    uch bg_green;
+    uch bg_blue;
+} mainprog_info;
+
+
+/* prototypes for public functions in readpng2.c */
+
+void readpng2_version_info(void);
+
+int readpng2_check_sig(uch *sig, int num);
+
+int readpng2_init(mainprog_info *mainprog_ptr);
+
+int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length);
+
+void readpng2_cleanup(mainprog_info *mainprog_ptr);
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readppm.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readppm.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/readppm.c	(revision 107811)
@@ -0,0 +1,188 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                              readppm.c
+
+  ---------------------------------------------------------------------------
+
+   This is a special-purpose replacement for readpng.c that allows binary
+   PPM files to be used in place of PNG images.
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007,2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "readpng.h"    /* typedefs, common macros, public prototypes */
+
+
+ulg  width, height;
+int  bit_depth, color_type, channels;
+uch  *image_data = NULL;
+FILE *saved_infile;
+
+
+void readpng_version_info()
+{
+    fprintf(stderr, "   Compiled without libpng, zlib or PBMPLUS/NetPBM.\n");
+}
+
+
+/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
+
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
+{
+    static uch ppmline[256];
+    int maxval;
+
+
+    saved_infile = infile;
+
+    fgets(ppmline, 256, infile);
+    if (ppmline[0] != 'P' || ppmline[1] != '6') {
+        fprintf(stderr, "ERROR:  not a PPM file\n");
+        return 1;
+    }
+    /* possible color types:  P5 = grayscale (0), P6 = RGB (2), P8 = RGBA (6) */
+    if (ppmline[1] == '6') {
+        color_type = 2;
+        channels = 3;
+    } else if (ppmline[1] == '8') {
+        color_type = 6;
+        channels = 4;
+    } else /* if (ppmline[1] == '5') */ {
+        color_type = 0;
+        channels = 1;
+    }
+
+    do {
+        fgets(ppmline, 256, infile);
+    } while (ppmline[0] == '#');
+    sscanf(ppmline, "%lu %lu", &width, &height);
+
+    do {
+        fgets(ppmline, 256, infile);
+    } while (ppmline[0] == '#');
+    sscanf(ppmline, "%d", &maxval);
+    if (maxval != 255) {
+        fprintf(stderr, "ERROR:  maxval = %d\n", maxval);
+        return 2;
+    }
+    bit_depth = 8;
+
+    *pWidth = width;
+    *pHeight = height;
+
+    return 0;
+}
+
+
+
+
+/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
+ * scales values to 8-bit if necessary */
+
+int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
+{
+    return 1;
+}
+
+
+
+
+/* display_exponent == LUT_exponent * CRT_exponent */
+
+uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
+{
+    ulg  rowbytes;
+
+
+    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
+     * transparency chunks to full alpha channel; strip 16-bit-per-sample
+     * images to 8 bits per sample; and convert grayscale to RGB[A] */
+
+    /* GRR WARNING:  grayscale needs to be expanded and channels reset! */
+
+    *pRowbytes = rowbytes = channels*width;
+    *pChannels = channels;
+
+    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
+
+    /* Guard against integer overflow */
+    if (height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n",
+        return NULL;
+    }
+
+    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
+        return NULL;
+    }
+
+    /* now we can go ahead and just read the whole image */
+
+    if (fread(image_data, 1L, rowbytes*height, saved_infile) <
+       rowbytes*height) {
+        free (image_data);
+        image_data = NULL;
+        return NULL;
+    }
+
+    return image_data;
+}
+
+
+void readpng_cleanup(int free_image_data)
+{
+    if (free_image_data && image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng-win.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng-win.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng-win.c	(revision 107811)
@@ -0,0 +1,735 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                             rpng-win.c
+
+   This program decodes and displays PNG images, with gamma correction and
+   optionally with a user-specified background color (in case the image has
+   transparency).  It is very nearly the most basic PNG viewer possible.
+   This version is for 32-bit Windows; it may compile under 16-bit Windows
+   with a little tweaking (or maybe not).
+
+   to do:
+    - handle quoted command-line args (especially filenames with spaces)
+    - have minimum window width:  oh well
+    - use %.1023s to simplify truncation of title-bar string?
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.00:  initial public release
+    - 1.01:  modified to allow abbreviated options; fixed long/ulong mis-
+              match; switched to png_jmpbuf() macro
+    - 1.02:  added extra set of parentheses to png_jmpbuf() macro; fixed
+              command-line parsing bug
+    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed improper display of usage screen on PNG error(s)
+    - 2.02:  check for integer overflow (Glenn R-P)
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng-win"
+#define LONGNAME  "Simple PNG Viewer for Windows"
+#define VERSION   "2.01 of 16 March 2008"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <windows.h>
+#ifdef __CYGWIN__
+/* getch replacement. Turns out, we don't really need this,
+ * but leave it here if we ever enable any of the uses of
+ * _getch in the main code
+ */
+#include <unistd.h>
+#include <termio.h>
+#include <sys/ioctl.h>
+int repl_getch( void )
+{
+  char ch;
+  int fd = fileno(stdin);
+  struct termio old_tty, new_tty;
+
+  ioctl(fd, TCGETA, &old_tty);
+  new_tty = old_tty;
+  new_tty.c_lflag &= ~(ICANON | ECHO | ISIG);
+  ioctl(fd, TCSETA, &new_tty);
+  fread(&ch, 1, sizeof(ch), stdin);
+  ioctl(fd, TCSETA, &old_tty);
+
+  return ch;
+}
+#define _getch repl_getch
+#else
+#include <conio.h>      /* only for _getch() */
+#endif
+
+/* #define DEBUG  :  this enables the Trace() macros */
+
+#include "readpng.h"    /* typedefs, common macros, readpng prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+/* local prototypes */
+static int        rpng_win_create_window(HINSTANCE hInst, int showmode);
+static int        rpng_win_display_image(void);
+static void       rpng_win_cleanup(void);
+LRESULT CALLBACK  rpng_win_wndproc(HWND, UINT, WPARAM, LPARAM);
+
+
+static char titlebar[1024];
+static char *progname = PROGNAME;
+static char *appname = LONGNAME;
+static char *filename;
+static FILE *infile;
+
+static char *bgstr;
+static uch bg_red=0, bg_green=0, bg_blue=0;
+
+static double display_exponent;
+
+static ulg image_width, image_height, image_rowbytes;
+static int image_channels;
+static uch *image_data;
+
+/* Windows-specific variables */
+static ulg wimage_rowbytes;
+static uch *dib;
+static uch *wimage_data;
+static BITMAPINFOHEADER *bmih;
+
+static HWND global_hwnd;
+
+
+
+
+int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
+{
+    char *args[1024];                 /* arbitrary limit, but should suffice */
+    char *p, *q, **argv = args;
+    int argc = 0;
+    int rc, alen, flen;
+    int error = 0;
+    int have_bg = FALSE;
+    double LUT_exponent;              /* just the lookup table */
+    double CRT_exponent = 2.2;        /* just the monitor */
+    double default_display_exponent;  /* whole display system */
+    MSG msg;
+
+
+    filename = (char *)NULL;
+
+#ifndef __CYGWIN__
+    /* First reenable console output, which normally goes to the bit bucket
+     * for windowed apps.  Closing the console window will terminate the
+     * app.  Thanks to David.Geldreich at realviz.com for supplying the magical
+     * incantation. */
+
+    AllocConsole();
+    freopen("CONOUT$", "a", stderr);
+    freopen("CONOUT$", "a", stdout);
+#endif
+
+
+    /* Next set the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities.  And
+     * yes, these ifdefs are completely wasted in a Windows program... */
+
+#if defined(NeXT)
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to get the
+     * "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        display_exponent = atof(p);
+    else
+        display_exponent = default_display_exponent;
+
+
+    /* Windows really hates command lines, so we have to set up our own argv.
+     * Note that we do NOT bother with quoted arguments here, so don't use
+     * filenames with spaces in 'em! */
+
+    argv[argc++] = PROGNAME;
+    p = cmd;
+    for (;;) {
+        if (*p == ' ')
+            while (*++p == ' ')
+                ;
+        /* now p points at the first non-space after some spaces */
+        if (*p == '\0')
+            break;    /* nothing after the spaces:  done */
+        argv[argc++] = q = p;
+        while (*q && *q != ' ')
+            ++q;
+        /* now q points at a space or the end of the string */
+        if (*q == '\0')
+            break;    /* last argv already terminated; quit */
+        *q = '\0';    /* change space to terminator */
+        p = q + 1;
+    }
+    argv[argc] = NULL;   /* terminate the argv array itself */
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                display_exponent = atof(*argv);
+                if (display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else
+                    have_bg = TRUE;
+            }
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename)
+        ++error;
+
+
+    /* print usage screen if any errors up to this point */
+
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+
+        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
+        readpng_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-gamma exp] [-bgcolor bg] file.png\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images\n"
+          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
+#ifndef __CYGWIN__
+          "Press Q or Esc to quit this usage screen.\n"
+#endif
+          "\n", PROGNAME, default_display_exponent);
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(1);
+    }
+
+
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
+            switch (rc) {
+                case 1:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] is not a PNG file: incorrect signature\n",
+                      filename);
+                    break;
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng_init() error\n");
+                    break;
+            }
+            ++error;
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(2);
+    } else {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+#ifndef __CYGWIN__
+        fprintf(stderr,
+          "\n   [console window:  closing this window will terminate %s]\n\n",
+          PROGNAME);
+#endif
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* if the user didn't specify a background color on the command line,
+     * check for one in the PNG file--if not, the initialized values of 0
+     * (black) will be used */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        bg_red   = (uch)r;
+        bg_green = (uch)g;
+        bg_blue  = (uch)b;
+    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
+        readpng_cleanup(TRUE);
+        fprintf(stderr, PROGNAME
+          ":  libpng error while checking for background color\n");
+        exit(2);
+    }
+
+
+    /* do the basic Windows initialization stuff, make the window and fill it
+     * with the background color */
+
+    if (rpng_win_create_window(hInst, showmode))
+        exit(2);
+
+
+    /* decode the image, all at once */
+
+    Trace((stderr, "calling readpng_get_image()\n"))
+    image_data = readpng_get_image(display_exponent, &image_channels,
+      &image_rowbytes);
+    Trace((stderr, "done with readpng_get_image()\n"))
+
+
+    /* done with PNG file, so clean up to minimize memory usage (but do NOT
+     * nuke image_data!) */
+
+    readpng_cleanup(FALSE);
+    fclose(infile);
+
+    if (!image_data) {
+        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
+        exit(3);
+    }
+
+
+    /* display image (composite with background if requested) */
+
+    Trace((stderr, "calling rpng_win_display_image()\n"))
+    if (rpng_win_display_image()) {
+        free(image_data);
+        exit(4);
+    }
+    Trace((stderr, "done with rpng_win_display_image()\n"))
+
+
+    /* wait for the user to tell us when to quit */
+
+    printf(
+#ifndef __CYGWIN__
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n"
+#else
+      "Done.  Press mouse button 1 (within image window) to quit.\n"
+#endif
+    );
+    fflush(stdout);
+
+    while (GetMessage(&msg, NULL, 0, 0)) {
+        TranslateMessage(&msg);
+        DispatchMessage(&msg);
+    }
+
+
+    /* OK, we're done:  clean up all image and Windows resources and go away */
+
+    rpng_win_cleanup();
+
+    return msg.wParam;
+}
+
+
+
+
+
+static int rpng_win_create_window(HINSTANCE hInst, int showmode)
+{
+    uch *dest;
+    int extra_width, extra_height;
+    ulg i, j;
+    WNDCLASSEX wndclass;
+
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the display-specific version of the image (round up
+    to multiple of 4 for Windows DIB).
+  ---------------------------------------------------------------------------*/
+
+    wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;
+
+    /* Guard against integer overflow */
+    if (image_height > ((size_t)(-1))/wimage_rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n");
+        return 4;   /* fail */
+    }
+
+    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
+                              wimage_rowbytes*image_height)))
+    {
+        return 4;   /* fail */
+    }
+
+/*---------------------------------------------------------------------------
+    Initialize the DIB.  Negative height means to use top-down BMP ordering
+    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
+    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
+    directly => wimage_data begins immediately after BMP header.
+  ---------------------------------------------------------------------------*/
+
+    memset(dib, 0, sizeof(BITMAPINFOHEADER));
+    bmih = (BITMAPINFOHEADER *)dib;
+    bmih->biSize = sizeof(BITMAPINFOHEADER);
+    bmih->biWidth = image_width;
+    bmih->biHeight = -((long)image_height);
+    bmih->biPlanes = 1;
+    bmih->biBitCount = 24;
+    bmih->biCompression = 0;
+    wimage_data = dib + sizeof(BITMAPINFOHEADER);
+
+/*---------------------------------------------------------------------------
+    Fill in background color (black by default); data are in BGR order.
+  ---------------------------------------------------------------------------*/
+
+    for (j = 0;  j < image_height;  ++j) {
+        dest = wimage_data + j*wimage_rowbytes;
+        for (i = image_width;  i > 0;  --i) {
+            *dest++ = bg_blue;
+            *dest++ = bg_green;
+            *dest++ = bg_red;
+        }
+    }
+
+/*---------------------------------------------------------------------------
+    Set the window parameters.
+  ---------------------------------------------------------------------------*/
+
+    memset(&wndclass, 0, sizeof(wndclass));
+
+    wndclass.cbSize = sizeof(wndclass);
+    wndclass.style = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc = rpng_win_wndproc;
+    wndclass.hInstance = hInst;
+    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
+    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
+    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
+    wndclass.lpszMenuName = NULL;
+    wndclass.lpszClassName = progname;
+    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
+
+    RegisterClassEx(&wndclass);
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
+                      GetSystemMetrics(SM_CXDLGFRAME));
+    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
+                      GetSystemMetrics(SM_CYDLGFRAME)) +
+                      GetSystemMetrics(SM_CYCAPTION);
+
+    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
+      CW_USEDEFAULT, CW_USEDEFAULT, image_width+extra_width,
+      image_height+extra_height, NULL, NULL, hInst, NULL);
+
+    ShowWindow(global_hwnd, showmode);
+    UpdateWindow(global_hwnd);
+
+    return 0;
+
+} /* end function rpng_win_create_window() */
+
+
+
+
+
+static int rpng_win_display_image()
+{
+    uch *src, *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow;
+    RECT rect;
+
+
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      image_channels))
+    Trace((stderr, "(width = %ld, rowbytes = %ld, wimage_rowbytes = %d)\n",
+      image_width, image_rowbytes, wimage_rowbytes))
+
+
+/*---------------------------------------------------------------------------
+    Blast image data to buffer.  This whole routine takes place before the
+    message loop begins, so there's no real point in any pseudo-progressive
+    display...
+  ---------------------------------------------------------------------------*/
+
+    for (lastrow = row = 0;  row < image_height;  ++row) {
+        src = image_data + row*image_rowbytes;
+        dest = wimage_data + row*wimage_rowbytes;
+        if (image_channels == 3) {
+            for (i = image_width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dest++ = b;
+                *dest++ = g;   /* note reverse order */
+                *dest++ = r;
+            }
+        } else /* if (image_channels == 4) */ {
+            for (i = image_width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (a == 255) {
+                    *dest++ = b;
+                    *dest++ = g;
+                    *dest++ = r;
+                } else if (a == 0) {
+                    *dest++ = bg_blue;
+                    *dest++ = bg_green;
+                    *dest++ = bg_red;
+                } else {
+                    /* this macro (copied from png.h) composites the
+                     * foreground and background values and puts the
+                     * result into the first argument; there are no
+                     * side effects with the first argument */
+                    alpha_composite(*dest++, b, a, bg_blue);
+                    alpha_composite(*dest++, g, a, bg_green);
+                    alpha_composite(*dest++, r, a, bg_red);
+                }
+            }
+        }
+        /* display after every 16 lines */
+        if (((row+1) & 0xf) == 0) {
+            rect.left = 0L;
+            rect.top = (LONG)lastrow;
+            rect.right = (LONG)image_width;      /* possibly off by one? */
+            rect.bottom = (LONG)lastrow + 16L;   /* possibly off by one? */
+            InvalidateRect(global_hwnd, &rect, FALSE);
+            UpdateWindow(global_hwnd);     /* similar to XFlush() */
+            lastrow = row + 1;
+        }
+    }
+
+    Trace((stderr, "calling final image-flush routine\n"))
+    if (lastrow < image_height) {
+        rect.left = 0L;
+        rect.top = (LONG)lastrow;
+        rect.right = (LONG)image_width;      /* possibly off by one? */
+        rect.bottom = (LONG)image_height;    /* possibly off by one? */
+        InvalidateRect(global_hwnd, &rect, FALSE);
+        UpdateWindow(global_hwnd);     /* similar to XFlush() */
+    }
+
+/*
+    last param determines whether or not background is wiped before paint
+    InvalidateRect(global_hwnd, NULL, TRUE);
+    UpdateWindow(global_hwnd);
+ */
+
+    return 0;
+}
+
+
+
+
+
+static void rpng_win_cleanup()
+{
+    if (image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+
+    if (dib) {
+        free(dib);
+        dib = NULL;
+    }
+}
+
+
+
+
+
+LRESULT CALLBACK rpng_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
+{
+    HDC         hdc;
+    PAINTSTRUCT ps;
+    int rc;
+
+    switch (iMsg) {
+        case WM_CREATE:
+            /* one-time processing here, if any */
+            return 0;
+
+        case WM_PAINT:
+            hdc = BeginPaint(hwnd, &ps);
+                    /*                    dest                          */
+            rc = StretchDIBits(hdc, 0, 0, image_width, image_height,
+                    /*                    source                        */
+                                    0, 0, image_width, image_height,
+                                    wimage_data, (BITMAPINFO *)bmih,
+                    /*              iUsage: no clue                     */
+                                    0, SRCCOPY);
+            EndPaint(hwnd, &ps);
+            return 0;
+
+        /* wait for the user to tell us when to quit */
+        case WM_CHAR:
+            switch (wP) {      /* only need one, so ignore repeat count */
+                case 'q':
+                case 'Q':
+                case 0x1B:     /* Esc key */
+                    PostQuitMessage(0);
+            }
+            return 0;
+
+        case WM_LBUTTONDOWN:   /* another way of quitting */
+        case WM_DESTROY:
+            PostQuitMessage(0);
+            return 0;
+    }
+
+    return DefWindowProc(hwnd, iMsg, wP, lP);
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng-x.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng-x.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng-x.c	(revision 107811)
@@ -0,0 +1,911 @@
+/*---------------------------------------------------------------------------
+
+   rpng - simple PNG display program                               rpng-x.c
+
+   This program decodes and displays PNG images, with gamma correction and
+   optionally with a user-specified background color (in case the image has
+   transparency).  It is very nearly the most basic PNG viewer possible.
+   This version is for the X Window System (tested by author under Unix and
+   by Martin Zinser under OpenVMS; may work under OS/2 with some tweaking).
+
+   to do:
+    - 8-bit (colormapped) X support
+    - use %.1023s to simplify truncation of title-bar string?
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options; fixed long/ulong mis-
+              match; switched to png_jmpbuf() macro
+    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
+    - 1.11:  added extra set of parentheses to png_jmpbuf() macro; fixed
+              command-line parsing bug
+    - 1.12:  fixed some small X memory leaks (thanks to François Petitjean)
+    - 1.13:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
+    - 1.14:  added support for X resources (thanks to Gerhard Niklasch)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed improper display of usage screen on PNG error(s)
+    - 2.02:  Added "void(argc);" statement to quiet pedantic compiler warnings
+             about unused variable (GR-P)
+    - 2.03:  check for integer overflow (Glenn R-P)
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng-x"
+#define LONGNAME  "Simple PNG Viewer for X"
+#define VERSION   "2.02 of 15 June 2014"
+#define RESNAME   "rpng"        /* our X resource application name */
+#define RESCLASS  "Rpng"        /* our X resource class name */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xos.h>
+#include <X11/keysym.h>
+
+/* #define DEBUG  :  this enables the Trace() macros */
+
+#include "readpng.h"   /* typedefs, common macros, readpng prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+/* local prototypes */
+static int  rpng_x_create_window(void);
+static int  rpng_x_display_image(void);
+static void rpng_x_cleanup(void);
+static int  rpng_x_msb(ulg u32val);
+
+
+static char titlebar[1024], *window_name = titlebar;
+static char *appname = LONGNAME;
+static char *icon_name = PROGNAME;
+static char *res_name = RESNAME;
+static char *res_class = RESCLASS;
+static char *filename;
+static FILE *infile;
+
+static char *bgstr;
+static uch bg_red=0, bg_green=0, bg_blue=0;
+
+static double display_exponent;
+
+static ulg image_width, image_height, image_rowbytes;
+static int image_channels;
+static uch *image_data;
+
+/* X-specific variables */
+static char *displayname;
+static XImage *ximage;
+static Display *display;
+static int depth;
+static Visual *visual;
+static XVisualInfo *visual_list;
+static int RShift, GShift, BShift;
+static ulg RMask, GMask, BMask;
+static Window window;
+static GC gc;
+static Colormap colormap;
+
+static int have_nondefault_visual = FALSE;
+static int have_colormap = FALSE;
+static int have_window = FALSE;
+static int have_gc = FALSE;
+/*
+ulg numcolors=0, pixels[256];
+ush reds[256], greens[256], blues[256];
+ */
+
+
+
+
+int main(int argc, char **argv)
+{
+#ifdef sgi
+    char tmpline[80];
+#endif
+    char *p;
+    int rc, alen, flen;
+    int error = 0;
+    int have_bg = FALSE;
+    double LUT_exponent;               /* just the lookup table */
+    double CRT_exponent = 2.2;         /* just the monitor */
+    double default_display_exponent;   /* whole display system */
+    XEvent e;
+    KeySym k;
+
+
+    displayname = (char *)NULL;
+    filename = (char *)NULL;
+
+
+    /* First set the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities. */
+
+#if defined(NeXT)
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to get the
+     * "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        display_exponent = atof(p);
+    else
+        display_exponent = default_display_exponent;
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-display", 2)) {
+            if (!*++argv)
+                ++error;
+            else
+                displayname = *argv;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                display_exponent = atof(*argv);
+                if (display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else
+                    have_bg = TRUE;
+            }
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename)
+        ++error;
+
+
+    /* print usage screen if any errors up to this point */
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+        readpng_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg] file.png\n"
+          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n",
+          PROGNAME, default_display_exponent);
+
+        fprintf(stderr, "\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images\n"
+          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
+          "is displayed) to quit.\n");
+        exit(1);
+    }
+
+
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
+            switch (rc) {
+                case 1:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] is not a PNG file: incorrect signature\n",
+                      filename);
+                    break;
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng_init() error\n");
+                    break;
+            }
+            ++error;
+        } else {
+            display = XOpenDisplay(displayname);
+            if (!display) {
+                readpng_cleanup(TRUE);
+                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
+                  displayname? displayname : "default");
+                ++error;
+            }
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    if (error) {
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+        exit(2);
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* if the user didn't specify a background color on the command line,
+     * check for one in the PNG file--if not, the initialized values of 0
+     * (black) will be used */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        bg_red   = (uch)r;
+        bg_green = (uch)g;
+        bg_blue  = (uch)b;
+    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
+        readpng_cleanup(TRUE);
+        fprintf(stderr, PROGNAME
+          ":  libpng error while checking for background color\n");
+        exit(2);
+    }
+
+
+    /* do the basic X initialization stuff, make the window and fill it
+     * with the background color */
+
+    if (rpng_x_create_window())
+        exit(2);
+
+
+    /* decode the image, all at once */
+
+    Trace((stderr, "calling readpng_get_image()\n"))
+    image_data = readpng_get_image(display_exponent, &image_channels,
+      &image_rowbytes);
+    Trace((stderr, "done with readpng_get_image()\n"))
+
+
+    /* done with PNG file, so clean up to minimize memory usage (but do NOT
+     * nuke image_data!) */
+
+    readpng_cleanup(FALSE);
+    fclose(infile);
+
+    if (!image_data) {
+        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
+        exit(3);
+    }
+
+
+    /* display image (composite with background if requested) */
+
+    Trace((stderr, "calling rpng_x_display_image()\n"))
+    if (rpng_x_display_image()) {
+        free(image_data);
+        exit(4);
+    }
+    Trace((stderr, "done with rpng_x_display_image()\n"))
+
+
+    /* wait for the user to tell us when to quit */
+
+    printf(
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
+    fflush(stdout);
+
+    do
+        XNextEvent(display, &e);
+    while (!(e.type == ButtonPress && e.xbutton.button == Button1) &&
+           !(e.type == KeyPress &&    /*  v--- or 1 for shifted keys */
+             ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape) ));
+
+
+    /* OK, we're done:  clean up all image and X resources and go away */
+
+    rpng_x_cleanup();
+
+    (void)argc; /* Unused */
+
+    return 0;
+}
+
+
+
+
+
+static int rpng_x_create_window(void)
+{
+    uch *xdata;
+    int need_colormap = FALSE;
+    int screen, pad;
+    ulg bg_pixel = 0L;
+    ulg attrmask;
+    Window root;
+    XEvent e;
+    XGCValues gcvalues;
+    XSetWindowAttributes attr;
+    XTextProperty windowName, *pWindowName = &windowName;
+    XTextProperty iconName, *pIconName = &iconName;
+    XVisualInfo visual_info;
+    XSizeHints *size_hints;
+    XWMHints *wm_hints;
+    XClassHint *class_hints;
+
+
+    screen = DefaultScreen(display);
+    depth = DisplayPlanes(display, screen);
+    root = RootWindow(display, screen);
+
+#ifdef DEBUG
+    XSynchronize(display, True);
+#endif
+
+#if 0
+/* GRR:  add 8-bit support */
+    if (/* depth != 8 && */ depth != 16 && depth != 24 && depth != 32) {
+        fprintf(stderr,
+          "screen depth %d not supported (only 16-, 24- or 32-bit TrueColor)\n",
+          depth);
+        return 2;
+    }
+
+    XMatchVisualInfo(display, screen, depth,
+      (depth == 8)? PseudoColor : TrueColor, &visual_info);
+    visual = visual_info.visual;
+#else
+    if (depth != 16 && depth != 24 && depth != 32) {
+        int visuals_matched = 0;
+
+        Trace((stderr, "default depth is %d:  checking other visuals\n",
+          depth))
+
+        /* 24-bit first */
+        visual_info.screen = screen;
+        visual_info.depth = 24;
+        visual_list = XGetVisualInfo(display,
+          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
+        if (visuals_matched == 0) {
+/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
+            fprintf(stderr, "default screen depth %d not supported, and no"
+              " 24-bit visuals found\n", depth);
+            return 2;
+        }
+        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
+          visuals_matched))
+        visual = visual_list[0].visual;
+        depth = visual_list[0].depth;
+/*
+        colormap_size = visual_list[0].colormap_size;
+        visual_class = visual->class;
+        visualID = XVisualIDFromVisual(visual);
+ */
+        have_nondefault_visual = TRUE;
+        need_colormap = TRUE;
+    } else {
+        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
+        visual = visual_info.visual;
+    }
+#endif
+
+    RMask = visual->red_mask;
+    GMask = visual->green_mask;
+    BMask = visual->blue_mask;
+
+/* GRR:  add/check 8-bit support */
+    if (depth == 8 || need_colormap) {
+        colormap = XCreateColormap(display, root, visual, AllocNone);
+        if (!colormap) {
+            fprintf(stderr, "XCreateColormap() failed\n");
+            return 2;
+        }
+        have_colormap = TRUE;
+    }
+    if (depth == 15 || depth == 16) {
+        RShift = 15 - rpng_x_msb(RMask);    /* these are right-shifts */
+        GShift = 15 - rpng_x_msb(GMask);
+        BShift = 15 - rpng_x_msb(BMask);
+    } else if (depth > 16) {
+#define NO_24BIT_MASKS
+#ifdef NO_24BIT_MASKS
+        RShift = rpng_x_msb(RMask) - 7;     /* these are left-shifts */
+        GShift = rpng_x_msb(GMask) - 7;
+        BShift = rpng_x_msb(BMask) - 7;
+#else
+        RShift = 7 - rpng_x_msb(RMask);     /* these are right-shifts, too */
+        GShift = 7 - rpng_x_msb(GMask);
+        BShift = 7 - rpng_x_msb(BMask);
+#endif
+    }
+    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
+        fprintf(stderr, "rpng internal logic error:  negative X shift(s)!\n");
+        return 2;
+    }
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    attr.backing_store = Always;
+    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
+    attrmask = CWBackingStore | CWEventMask;
+    if (have_nondefault_visual) {
+        attr.colormap = colormap;
+        attr.background_pixel = 0;
+        attr.border_pixel = 1;
+        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
+    }
+
+    window = XCreateWindow(display, root, 0, 0, image_width, image_height, 0,
+      depth, InputOutput, visual, attrmask, &attr);
+
+    if (window == None) {
+        fprintf(stderr, "XCreateWindow() failed\n");
+        return 2;
+    } else
+        have_window = TRUE;
+
+    if (depth == 8)
+        XSetWindowColormap(display, window, colormap);
+
+    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
+        pWindowName = NULL;
+    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
+        pIconName = NULL;
+
+    /* OK if any hints allocation fails; XSetWMProperties() allows NULLs */
+
+    if ((size_hints = XAllocSizeHints()) != NULL) {
+        /* window will not be resizable */
+        size_hints->flags = PMinSize | PMaxSize;
+        size_hints->min_width = size_hints->max_width = (int)image_width;
+        size_hints->min_height = size_hints->max_height = (int)image_height;
+    }
+
+    if ((wm_hints = XAllocWMHints()) != NULL) {
+        wm_hints->initial_state = NormalState;
+        wm_hints->input = True;
+     /* wm_hints->icon_pixmap = icon_pixmap; */
+        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
+    }
+
+    if ((class_hints = XAllocClassHint()) != NULL) {
+        class_hints->res_name = res_name;
+        class_hints->res_class = res_class;
+    }
+
+    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
+      size_hints, wm_hints, class_hints);
+
+    /* various properties and hints no longer needed; free memory */
+    if (pWindowName)
+       XFree(pWindowName->value);
+    if (pIconName)
+       XFree(pIconName->value);
+    if (size_hints)
+        XFree(size_hints);
+    if (wm_hints)
+       XFree(wm_hints);
+    if (class_hints)
+       XFree(class_hints);
+
+    XMapWindow(display, window);
+
+    gc = XCreateGC(display, window, 0, &gcvalues);
+    have_gc = TRUE;
+
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        bg_pixel = ((ulg)bg_red   << RShift) |
+                   ((ulg)bg_green << GShift) |
+                   ((ulg)bg_blue  << BShift);
+    } else if (depth == 16) {
+        bg_pixel = ((((ulg)bg_red   << 8) >> RShift) & RMask) |
+                   ((((ulg)bg_green << 8) >> GShift) & GMask) |
+                   ((((ulg)bg_blue  << 8) >> BShift) & BMask);
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    XSetForeground(display, gc, bg_pixel);
+    XFillRectangle(display, window, gc, 0, 0, image_width, image_height);
+
+/*---------------------------------------------------------------------------
+    Wait for first Expose event to do any drawing, then flush.
+  ---------------------------------------------------------------------------*/
+
+    do
+        XNextEvent(display, &e);
+    while (e.type != Expose || e.xexpose.count);
+
+    XFlush(display);
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the X- and display-specific version of the image.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        xdata = (uch *)malloc(4*image_width*image_height);
+        pad = 32;
+    } else if (depth == 16) {
+        xdata = (uch *)malloc(2*image_width*image_height);
+        pad = 16;
+    } else /* depth == 8 */ {
+        xdata = (uch *)malloc(image_width*image_height);
+        pad = 8;
+    }
+
+    if (!xdata) {
+        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
+        return 4;
+    }
+
+    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
+      (char *)xdata, image_width, image_height, pad, 0);
+
+    if (!ximage) {
+        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
+        free(xdata);
+        return 3;
+    }
+
+    /* to avoid testing the byte order every pixel (or doubling the size of
+     * the drawing routine with a giant if-test), we arbitrarily set the byte
+     * order to MSBFirst and let Xlib worry about inverting things on little-
+     * endian machines (like Linux/x86, old VAXen, etc.)--this is not the most
+     * efficient approach (the giant if-test would be better), but in the
+     * interest of clarity, we take the easy way out... */
+
+    ximage->byte_order = MSBFirst;
+
+    return 0;
+
+} /* end function rpng_x_create_window() */
+
+
+
+
+
+static int rpng_x_display_image(void)
+{
+    uch *src;
+    char *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow = 0;
+    ulg pixel;
+    int ximage_rowbytes = ximage->bytes_per_line;
+/*  int bpp = ximage->bits_per_pixel;  */
+
+
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      image_channels))
+    Trace((stderr, "   (width = %ld, rowbytes = %ld, ximage_rowbytes = %d)\n",
+      image_width, image_rowbytes, ximage_rowbytes))
+    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
+    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
+      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+
+        for (lastrow = row = 0;  row < image_height;  ++row) {
+            src = image_data + row*image_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (image_channels == 3) {
+                for (i = image_width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    /* GRR BUG:  this assumes bpp == 32, but may be 24: */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+#endif
+                }
+            } else /* if (image_channels == 4) */ {
+                for (i = image_width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (a == 255) {
+                        red   = r;
+                        green = g;
+                        blue  = b;
+                    } else if (a == 0) {
+                        red   = bg_red;
+                        green = bg_green;
+                        blue  = bg_blue;
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result into the
+                         * first argument */
+                        alpha_composite(red,   r, a, bg_red);
+                        alpha_composite(green, g, a, bg_green);
+                        alpha_composite(blue,  b, a, bg_blue);
+                    }
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, image_width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        for (lastrow = row = 0;  row < image_height;  ++row) {
+            src = image_data + row*image_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (image_channels == 3) {
+                for (i = image_width;  i > 0;  --i) {
+                    red   = ((ush)(*src) << 8);
+                    ++src;
+                    green = ((ush)(*src) << 8);
+                    ++src;
+                    blue  = ((ush)(*src) << 8);
+                    ++src;
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else /* if (image_channels == 4) */ {
+                for (i = image_width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (a == 255) {
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    } else if (a == 0) {
+                        red   = ((ush)bg_red   << 8);
+                        green = ((ush)bg_green << 8);
+                        blue  = ((ush)bg_blue  << 8);
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result back into
+                         * the first argument (== fg byte here:  safe) */
+                        alpha_composite(r, r, a, bg_red);
+                        alpha_composite(g, g, a, bg_green);
+                        alpha_composite(b, b, a, bg_blue);
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    }
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, image_width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    Trace((stderr, "calling final XPutImage()\n"))
+    if (lastrow < image_height) {
+        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+          (int)lastrow, image_width, image_height-lastrow);
+        XFlush(display);
+    }
+
+    return 0;
+}
+
+
+
+
+static void rpng_x_cleanup(void)
+{
+    if (image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+
+    if (ximage) {
+        if (ximage->data) {
+            free(ximage->data);           /* we allocated it, so we free it */
+            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
+        }
+        XDestroyImage(ximage);
+        ximage = NULL;
+    }
+
+    if (have_gc)
+        XFreeGC(display, gc);
+
+    if (have_window)
+        XDestroyWindow(display, window);
+
+    if (have_colormap)
+        XFreeColormap(display, colormap);
+
+    if (have_nondefault_visual)
+        XFree(visual_list);
+}
+
+
+
+
+
+static int rpng_x_msb(ulg u32val)
+{
+    int i;
+
+    for (i = 31;  i >= 0;  --i) {
+        if (u32val & 0x80000000L)
+            break;
+        u32val <<= 1;
+    }
+    return i;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng2-win.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng2-win.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng2-win.c	(revision 107811)
@@ -0,0 +1,1261 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                rpng2-win.c
+
+   This program decodes and displays PNG files progressively, as if it were
+   a web browser (though the front end is only set up to read from files).
+   It supports gamma correction, user-specified background colors, and user-
+   specified background patterns (for transparent images).  This version is
+   for 32-bit Windows; it may compile under 16-bit Windows with a little
+   tweaking (or maybe not).  Thanks to Adam Costello and Pieter S. van der
+   Meulen for the "diamond" and "radial waves" patterns, respectively.
+
+   to do (someday, maybe):
+    - handle quoted command-line args (especially filenames with spaces)
+    - finish resizable checkerboard-gradient (sizes 4-128?)
+    - use %.1023s to simplify truncation of title-bar string?
+    - have minimum window width:  oh well
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  fixed cut-and-paste error in usage screen (oops...)
+    - 1.03:  modified to allow abbreviated options
+    - 1.04:  removed bogus extra argument from usage fprintf() [Glenn R-P?];
+              fixed command-line parsing bug
+    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
+    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
+    - 1.21:  made minor tweak to usage screen to fit within 25-line console
+    - 1.22:  added AMD64/EM64T support (__x86_64__)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed 64-bit typo in readpng2.c
+    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
+              unexpected-EOF and file-read-error cases
+    - 2.03:  removed runtime MMX-enabling/disabling and obsolete -mmx* options
+    - 2.04:  check for integer overflow (Glenn R-P)
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2008, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng2-win"
+#define LONGNAME  "Progressive PNG Viewer for Windows"
+#define VERSION   "2.02 of 16 March 2008"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <setjmp.h>    /* for jmpbuf declaration in readpng2.h */
+#include <time.h>
+#include <math.h>      /* only for PvdM background code */
+#include <windows.h>
+#ifdef __CYGWIN__
+/* getch replacement. Turns out, we don't really need this,
+ * but leave it here if we ever enable any of the uses of
+ * _getch in the main code
+ */
+#include <unistd.h>
+#include <termio.h>
+#include <sys/ioctl.h>
+int repl_getch( void )
+{
+  char ch;
+  int fd = fileno(stdin);
+  struct termio old_tty, new_tty;
+
+  ioctl(fd, TCGETA, &old_tty);
+  new_tty = old_tty;
+  new_tty.c_lflag &= ~(ICANON | ECHO | ISIG);
+  ioctl(fd, TCSETA, &new_tty);
+  fread(&ch, 1, sizeof(ch), stdin);
+  ioctl(fd, TCSETA, &old_tty);
+
+  return ch;
+}
+#define _getch repl_getch
+#else
+#include <conio.h>     /* only for _getch() */
+#endif
+
+/* all for PvdM background code: */
+#ifndef PI
+#  define PI             3.141592653589793238
+#endif
+#define PI_2             (PI*0.5)
+#define INV_PI_360       (360.0 / PI)
+#define MAX(a,b)         (a>b?a:b)
+#define MIN(a,b)         (a<b?a:b)
+#define CLIP(a,min,max)  MAX(min,MIN((a),max))
+#define ABS(a)           ((a)<0?-(a):(a))
+#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
+#define ROUNDF(f)        ((int)(f + 0.5))
+
+#define rgb1_max   bg_freq
+#define rgb1_min   bg_gray
+#define rgb2_max   bg_bsat
+#define rgb2_min   bg_brot
+
+/* #define DEBUG */     /* this enables the Trace() macros */
+
+#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
+                          *  block size corresponds roughly to a download
+                          *  speed 10% faster than theoretical 33.6K maximum
+                          *  (assuming 8 data bits, 1 stop bit and no other
+                          *  overhead) */
+
+/* local prototypes */
+static void       rpng2_win_init(void);
+static int        rpng2_win_create_window(void);
+static int        rpng2_win_load_bg_image(void);
+static void       rpng2_win_display_row(ulg row);
+static void       rpng2_win_finish_display(void);
+static void       rpng2_win_cleanup(void);
+LRESULT CALLBACK  rpng2_win_wndproc(HWND, UINT, WPARAM, LPARAM);
+
+
+static char titlebar[1024];
+static char *progname = PROGNAME;
+static char *appname = LONGNAME;
+static char *filename;
+static FILE *infile;
+
+static mainprog_info rpng2_info;
+
+static uch inbuf[INBUFSIZE];
+static int incount;
+
+static int pat = 6;         /* must be less than num_bgpat */
+static int bg_image = 0;
+static int bgscale = 16;
+static ulg bg_rowbytes;
+static uch *bg_data;
+
+static struct rgb_color {
+    uch r, g, b;
+} rgb[] = {
+    {  0,   0,   0},    /*  0:  black */
+    {255, 255, 255},    /*  1:  white */
+    {173, 132,  57},    /*  2:  tan */
+    { 64, 132,   0},    /*  3:  medium green */
+    {189, 117,   1},    /*  4:  gold */
+    {253, 249,   1},    /*  5:  yellow */
+    {  0,   0, 255},    /*  6:  blue */
+    {  0,   0, 120},    /*  7:  medium blue */
+    {255,   0, 255},    /*  8:  magenta */
+    { 64,   0,  64},    /*  9:  dark magenta */
+    {255,   0,   0},    /* 10:  red */
+    { 64,   0,   0},    /* 11:  dark red */
+    {255, 127,   0},    /* 12:  orange */
+    {192,  96,   0},    /* 13:  darker orange */
+    { 24,  60,   0},    /* 14:  dark green-yellow */
+    { 85, 125, 200}     /* 15:  ice blue */
+};
+/* not used for now, but should be for error-checking:
+static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
+ */
+
+/*
+    This whole struct is a fairly cheesy way to keep the number of
+    command-line options to a minimum.  The radial-waves background
+    type is a particularly poor fit to the integer elements of the
+    struct...but a few macros and a little fixed-point math will do
+    wonders for ya.
+
+    type bits:
+       F E D C B A 9 8 7 6 5 4 3 2 1 0
+                             | | | | |
+                             | | +-+-+-- 0 = sharp-edged checkerboard
+                             | |         1 = soft diamonds
+                             | |         2 = radial waves
+                             | |       3-7 = undefined
+                             | +-- gradient #2 inverted?
+                             +-- alternating columns inverted?
+ */
+static struct background_pattern {
+    ush type;
+    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
+    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
+} bg[] = {
+    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
+    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
+    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
+    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
+    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
+    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
+    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
+    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
+    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
+    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
+    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
+    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
+    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
+    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
+    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
+    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
+};
+static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
+
+
+/* Windows-specific global variables (could go in struct, but messy...) */
+static ulg wimage_rowbytes;
+static uch *dib;
+static uch *wimage_data;
+static BITMAPINFOHEADER *bmih;
+
+static HWND global_hwnd;
+static HINSTANCE global_hInst;
+static int global_showmode;
+
+
+
+
+int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
+{
+    char *args[1024];                 /* arbitrary limit, but should suffice */
+    char **argv = args;
+    char *p, *q, *bgstr = NULL;
+    int argc = 0;
+    int rc, alen, flen;
+    int error = 0;
+    int timing = FALSE;
+    int have_bg = FALSE;
+    double LUT_exponent;              /* just the lookup table */
+    double CRT_exponent = 2.2;        /* just the monitor */
+    double default_display_exponent;  /* whole display system */
+    MSG msg;
+
+
+    /* First initialize a few things, just to be sure--memset takes care of
+     * default background color (black), booleans (FALSE), pointers (NULL),
+     * etc. */
+
+    global_hInst = hInst;
+    global_showmode = showmode;
+    filename = (char *)NULL;
+    memset(&rpng2_info, 0, sizeof(mainprog_info));
+
+#ifndef __CYGWIN__
+    /* Next reenable console output, which normally goes to the bit bucket
+     * for windowed apps.  Closing the console window will terminate the
+     * app.  Thanks to David.Geldreich at realviz.com for supplying the magical
+     * incantation. */
+
+    AllocConsole();
+    freopen("CONOUT$", "a", stderr);
+    freopen("CONOUT$", "a", stdout);
+#endif
+
+    /* Set the default value for our display-system exponent, i.e., the
+     * product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities.  And
+     * yes, these ifdefs are completely wasted in a Windows program... */
+
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        rpng2_info.display_exponent = atof(p);
+    else
+        rpng2_info.display_exponent = default_display_exponent;
+
+
+    /* Windows really hates command lines, so we have to set up our own argv.
+     * Note that we do NOT bother with quoted arguments here, so don't use
+     * filenames with spaces in 'em! */
+
+    argv[argc++] = PROGNAME;
+    p = cmd;
+    for (;;) {
+        if (*p == ' ')
+            while (*++p == ' ')
+                ;
+        /* now p points at the first non-space after some spaces */
+        if (*p == '\0')
+            break;    /* nothing after the spaces:  done */
+        argv[argc++] = q = p;
+        while (*q && *q != ' ')
+            ++q;
+        /* now q points at a space or the end of the string */
+        if (*q == '\0')
+            break;    /* last argv already terminated; quit */
+        *q = '\0';    /* change space to terminator */
+        p = q + 1;
+    }
+    argv[argc] = NULL;   /* terminate the argv array itself */
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                rpng2_info.display_exponent = atof(*argv);
+                if (rpng2_info.display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    have_bg = TRUE;
+                    bg_image = FALSE;
+                }
+            }
+        } else if (!strncmp(*argv, "-bgpat", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                pat = atoi(*argv) - 1;
+                if (pat < 0 || pat >= num_bgpat)
+                    ++error;
+                else {
+                    bg_image = TRUE;
+                    have_bg = FALSE;
+                }
+            }
+        } else if (!strncmp(*argv, "-timing", 2)) {
+            timing = TRUE;
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename)
+        ++error;
+
+
+    /* print usage screen if any errors up to this point */
+
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+
+        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
+        readpng2_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-gamma exp] [-bgcolor bg | -bgpat pat] [-timing]\n"
+          "        %*s file.png\n\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images; overrides -bgpat option\n"
+          "    pat \tdesired background pattern number (1-%d); used with\n"
+          "\t\t  transparent images; overrides -bgcolor option\n"
+          "    -timing\tenables delay for every block read, to simulate modem\n"
+          "\t\t  download of image (~36 Kbps)\n"
+          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
+#ifndef __CYGWIN__
+          "Press Q or Esc to quit this usage screen. ",
+#else
+          ,
+#endif
+          PROGNAME,
+#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__)) && \
+    !(defined(__CYGWIN__) || defined(__MINGW32__))
+          (int)strlen(PROGNAME), " ",
+#endif
+          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat);
+        fflush(stderr);
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(1);
+    }
+
+
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
+            fprintf(stderr, PROGNAME
+              ":  [%s] is not a PNG file: incorrect signature\n",
+              filename);
+            ++error;
+        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
+            switch (rc) {
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng2_init() error\n");
+                    break;
+            }
+            ++error;
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(2);
+    } else {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+#ifndef __CYGWIN__
+        fprintf(stderr,
+          "\n   [console window:  closing this window will terminate %s]\n\n",
+          PROGNAME);
+#endif
+        fflush(stderr);
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* set some final rpng2_info variables before entering main data loop */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        rpng2_info.bg_red   = (uch)r;
+        rpng2_info.bg_green = (uch)g;
+        rpng2_info.bg_blue  = (uch)b;
+    } else
+        rpng2_info.need_bgcolor = TRUE;
+
+    rpng2_info.state = kPreInit;
+    rpng2_info.mainprog_init = rpng2_win_init;
+    rpng2_info.mainprog_display_row = rpng2_win_display_row;
+    rpng2_info.mainprog_finish_display = rpng2_win_finish_display;
+
+
+    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
+     * the loop to deal with our first buffer of data (read in above to verify
+     * that the file is a PNG image), then loop through the file and continue
+     * calling the same routine to handle each chunk of data.  It in turn
+     * passes the data to libpng, which will invoke one or more of our call-
+     * backs as decoded data become available.  We optionally call Sleep() for
+     * one second per iteration to simulate downloading the image via an analog
+     * modem. */
+
+    for (;;) {
+        Trace((stderr, "about to call readpng2_decode_data()\n"))
+        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
+            ++error;
+        Trace((stderr, "done with readpng2_decode_data()\n"))
+
+        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
+            if (rpng2_info.state == kDone) {
+                Trace((stderr, "done decoding PNG image\n"))
+            } else if (ferror(infile)) {
+                fprintf(stderr, PROGNAME
+                  ":  error while reading PNG image file\n");
+                exit(3);
+            } else if (feof(infile)) {
+                fprintf(stderr, PROGNAME ":  end of file reached "
+                  "(unexpectedly) while reading PNG image file\n");
+                exit(3);
+            } else /* if (error) */ {
+                /* will print error message below */
+            }
+            break;
+        }
+
+        if (timing)
+            Sleep(1000L);
+
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+    }
+
+
+    /* clean up PNG stuff and report any decoding errors */
+
+    fclose(infile);
+    Trace((stderr, "about to call readpng2_cleanup()\n"))
+    readpng2_cleanup(&rpng2_info);
+
+    if (error) {
+        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
+        exit(3);
+    }
+
+
+    /* wait for the user to tell us when to quit */
+
+    while (GetMessage(&msg, NULL, 0, 0)) {
+        TranslateMessage(&msg);
+        DispatchMessage(&msg);
+    }
+
+
+    /* we're done:  clean up all image and Windows resources and go away */
+
+    Trace((stderr, "about to call rpng2_win_cleanup()\n"))
+    rpng2_win_cleanup();
+
+    return msg.wParam;
+}
+
+
+
+
+
+/* this function is called by readpng2_info_callback() in readpng2.c, which
+ * in turn is called by libpng after all of the pre-IDAT chunks have been
+ * read and processed--i.e., we now have enough info to finish initializing */
+
+static void rpng2_win_init()
+{
+    ulg i;
+    ulg rowbytes = rpng2_info.rowbytes;
+
+    Trace((stderr, "beginning rpng2_win_init()\n"))
+    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
+    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
+    Trace((stderr, "  height = %ld\n", rpng2_info.height))
+
+    /* Guard against integer overflow */
+    if (rpng2_info.height > ((size_t)(-1))/rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n",
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
+    if (!rpng2_info.image_data) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
+    if (!rpng2_info.row_pointers) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    for (i = 0;  i < rpng2_info.height;  ++i)
+        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
+
+/*---------------------------------------------------------------------------
+    Do the basic Windows initialization stuff, make the window, and fill it
+    with the user-specified, file-specified or default background color.
+  ---------------------------------------------------------------------------*/
+
+    if (rpng2_win_create_window()) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.state = kWindowInit;
+}
+
+
+
+
+
+static int rpng2_win_create_window()
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *dest;
+    int extra_width, extra_height;
+    ulg i, j;
+    WNDCLASSEX wndclass;
+    RECT rect;
+
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the display-specific version of the image (round up
+    to multiple of 4 for Windows DIB).
+  ---------------------------------------------------------------------------*/
+
+    wimage_rowbytes = ((3*rpng2_info.width + 3L) >> 2) << 2;
+
+    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
+                              wimage_rowbytes*rpng2_info.height)))
+    {
+        return 4;   /* fail */
+    }
+
+/*---------------------------------------------------------------------------
+    Initialize the DIB.  Negative height means to use top-down BMP ordering
+    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
+    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
+    directly => wimage_data begins immediately after BMP header.
+  ---------------------------------------------------------------------------*/
+
+    memset(dib, 0, sizeof(BITMAPINFOHEADER));
+    bmih = (BITMAPINFOHEADER *)dib;
+    bmih->biSize = sizeof(BITMAPINFOHEADER);
+    bmih->biWidth = rpng2_info.width;
+    bmih->biHeight = -((long)rpng2_info.height);
+    bmih->biPlanes = 1;
+    bmih->biBitCount = 24;
+    bmih->biCompression = 0;
+    wimage_data = dib + sizeof(BITMAPINFOHEADER);
+
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color (default is black), but
+    defer loading faked "background image" until window is displayed (may be
+    slow to compute).  Data are in BGR order.
+  ---------------------------------------------------------------------------*/
+
+    if (bg_image) {   /* just fill with black for now */
+        memset(wimage_data, 0, wimage_rowbytes*rpng2_info.height);
+    } else {
+        for (j = 0;  j < rpng2_info.height;  ++j) {
+            dest = wimage_data + j*wimage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                *dest++ = bg_blue;
+                *dest++ = bg_green;
+                *dest++ = bg_red;
+            }
+        }
+    }
+
+/*---------------------------------------------------------------------------
+    Set the window parameters.
+  ---------------------------------------------------------------------------*/
+
+    memset(&wndclass, 0, sizeof(wndclass));
+
+    wndclass.cbSize = sizeof(wndclass);
+    wndclass.style = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc = rpng2_win_wndproc;
+    wndclass.hInstance = global_hInst;
+    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
+    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
+    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
+    wndclass.lpszMenuName = NULL;
+    wndclass.lpszClassName = progname;
+    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
+
+    RegisterClassEx(&wndclass);
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
+                      GetSystemMetrics(SM_CXDLGFRAME));
+    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
+                      GetSystemMetrics(SM_CYDLGFRAME)) +
+                      GetSystemMetrics(SM_CYCAPTION);
+
+    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
+      CW_USEDEFAULT, CW_USEDEFAULT, rpng2_info.width+extra_width,
+      rpng2_info.height+extra_height, NULL, NULL, global_hInst, NULL);
+
+    ShowWindow(global_hwnd, global_showmode);
+    UpdateWindow(global_hwnd);
+
+/*---------------------------------------------------------------------------
+    Now compute the background image and display it.  If it fails (memory
+    allocation), revert to a plain background color.
+  ---------------------------------------------------------------------------*/
+
+    if (bg_image) {
+        static const char *msg = "Computing background image...";
+        int x, y, len = strlen(msg);
+        HDC hdc = GetDC(global_hwnd);
+        TEXTMETRIC tm;
+
+        GetTextMetrics(hdc, &tm);
+        x = (rpng2_info.width - len*tm.tmAveCharWidth)/2;
+        y = (rpng2_info.height - tm.tmHeight)/2;
+        SetBkMode(hdc, TRANSPARENT);
+        SetTextColor(hdc, GetSysColor(COLOR_HIGHLIGHTTEXT));
+        /* this can still begin out of bounds even if x is positive (???): */
+        TextOut(hdc, ((x < 0)? 0 : x), ((y < 0)? 0 : y), msg, len);
+        ReleaseDC(global_hwnd, hdc);
+
+        rpng2_win_load_bg_image();   /* resets bg_image if fails */
+    }
+
+    if (!bg_image) {
+        for (j = 0;  j < rpng2_info.height;  ++j) {
+            dest = wimage_data + j*wimage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                *dest++ = bg_blue;
+                *dest++ = bg_green;
+                *dest++ = bg_red;
+            }
+        }
+    }
+
+    rect.left = 0L;
+    rect.top = 0L;
+    rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
+    rect.bottom = (LONG)rpng2_info.height;     /* possibly off by one? */
+    InvalidateRect(global_hwnd, &rect, FALSE);
+    UpdateWindow(global_hwnd);                 /* similar to XFlush() */
+
+    return 0;
+
+} /* end function rpng2_win_create_window() */
+
+
+
+
+
+static int rpng2_win_load_bg_image()
+{
+    uch *src, *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max = (bgscale-1);
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    ulg i, row;
+
+/*---------------------------------------------------------------------------
+    Allocate buffer for fake background image to be used with transparent
+    images; if this fails, revert to plain background color.
+  ---------------------------------------------------------------------------*/
+
+    bg_rowbytes = 3 * rpng2_info.width;
+    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
+    if (!bg_data) {
+        fprintf(stderr, PROGNAME
+          ":  unable to allocate memory for background image\n");
+        bg_image = 0;
+        return 1;
+    }
+
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = row % bgscale;
+            even_odd_vert = (row / bgscale) & 1;
+
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (i / bgscale) & 1;
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {         /* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {                     /* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;        /* not inverted or */
+                        *dest++ = g2;        /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;    /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 1) {
+
+        hmax = (bgscale-1)/2;   /* half the max weight of a color */
+        max = 2*hmax;           /* the max weight of a color */
+
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = row % bgscale;
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = i % bgscale;
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+
+        fprintf(stderr, "%s:  computing radial background...",
+          PROGNAME);
+        fflush(stderr);
+
+        hh = rpng2_info.height / 2;
+        hw = rpng2_info.width / 2;
+
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = row - hh;
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = i - hw;
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+        fprintf(stderr, "done.\n");
+        fflush(stderr);
+    }
+
+/*---------------------------------------------------------------------------
+    Blast background image to display buffer before beginning PNG decode;
+    calling function will handle invalidation and UpdateWindow() call.
+  ---------------------------------------------------------------------------*/
+
+    for (row = 0;  row < rpng2_info.height;  ++row) {
+        src = bg_data + row*bg_rowbytes;
+        dest = wimage_data + row*wimage_rowbytes;
+        for (i = rpng2_info.width;  i > 0;  --i) {
+            r1 = *src++;
+            g1 = *src++;
+            b1 = *src++;
+            *dest++ = b1;
+            *dest++ = g1;   /* note reverse order */
+            *dest++ = r1;
+        }
+    }
+
+    return 0;
+
+} /* end function rpng2_win_load_bg_image() */
+
+
+
+
+
+static void rpng2_win_display_row(ulg row)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL, *dest;
+    uch r, g, b, a;
+    ulg i;
+    static int rows=0;
+    static ulg firstrow;
+
+/*---------------------------------------------------------------------------
+    rows and firstrow simply track how many rows (and which ones) have not
+    yet been displayed; alternatively, we could call InvalidateRect() for
+    every row and not bother with the records-keeping.
+  ---------------------------------------------------------------------------*/
+
+    Trace((stderr, "beginning rpng2_win_display_row()\n"))
+
+    if (rows == 0)
+        firstrow = row;   /* first row not yet displayed */
+
+    ++rows;   /* count of rows received but not yet displayed */
+
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct and the lack of an outer
+    loop (over rows), this routine is identical to rpng_win_display_image()
+    in the non-progressive version of the program.
+  ---------------------------------------------------------------------------*/
+
+    src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+    if (bg_image)
+        src2 = bg_data + row*bg_rowbytes;
+    dest = wimage_data + row*wimage_rowbytes;
+
+    if (rpng2_info.channels == 3) {
+        for (i = rpng2_info.width;  i > 0;  --i) {
+            r = *src++;
+            g = *src++;
+            b = *src++;
+            *dest++ = b;
+            *dest++ = g;   /* note reverse order */
+            *dest++ = r;
+        }
+    } else /* if (rpng2_info.channels == 4) */ {
+        for (i = rpng2_info.width;  i > 0;  --i) {
+            r = *src++;
+            g = *src++;
+            b = *src++;
+            a = *src++;
+            if (bg_image) {
+                bg_red   = *src2++;
+                bg_green = *src2++;
+                bg_blue  = *src2++;
+            }
+            if (a == 255) {
+                *dest++ = b;
+                *dest++ = g;
+                *dest++ = r;
+            } else if (a == 0) {
+                *dest++ = bg_blue;
+                *dest++ = bg_green;
+                *dest++ = bg_red;
+            } else {
+                /* this macro (copied from png.h) composites the
+                 * foreground and background values and puts the
+                 * result into the first argument; there are no
+                 * side effects with the first argument */
+                alpha_composite(*dest++, b, a, bg_blue);
+                alpha_composite(*dest++, g, a, bg_green);
+                alpha_composite(*dest++, r, a, bg_red);
+            }
+        }
+    }
+
+/*---------------------------------------------------------------------------
+    Display after every 16 rows or when on last row.  (Region may include
+    previously displayed lines due to interlacing--i.e., not contiguous.)
+  ---------------------------------------------------------------------------*/
+
+    if ((rows & 0xf) == 0 || row == rpng2_info.height-1) {
+        RECT rect;
+
+        rect.left = 0L;
+        rect.top = (LONG)firstrow;
+        rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
+        rect.bottom = (LONG)row + 1L;              /* possibly off by one? */
+        InvalidateRect(global_hwnd, &rect, FALSE);
+        UpdateWindow(global_hwnd);                 /* similar to XFlush() */
+        rows = 0;
+    }
+
+} /* end function rpng2_win_display_row() */
+
+
+
+
+
+static void rpng2_win_finish_display()
+{
+    Trace((stderr, "beginning rpng2_win_finish_display()\n"))
+
+    /* last row has already been displayed by rpng2_win_display_row(), so
+     * we have nothing to do here except set a flag and let the user know
+     * that the image is done */
+
+    rpng2_info.state = kDone;
+    printf(
+#ifndef __CYGWIN__
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n"
+#else
+      "Done.  Press mouse button 1 (within image window) to quit.\n"
+#endif
+    );
+    fflush(stdout);
+}
+
+
+
+
+
+static void rpng2_win_cleanup()
+{
+    if (bg_image && bg_data) {
+        free(bg_data);
+        bg_data = NULL;
+    }
+
+    if (rpng2_info.image_data) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+    }
+
+    if (rpng2_info.row_pointers) {
+        free(rpng2_info.row_pointers);
+        rpng2_info.row_pointers = NULL;
+    }
+
+    if (dib) {
+        free(dib);
+        dib = NULL;
+    }
+}
+
+
+
+
+
+LRESULT CALLBACK rpng2_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
+{
+    HDC         hdc;
+    PAINTSTRUCT ps;
+    int rc;
+
+    switch (iMsg) {
+        case WM_CREATE:
+            /* one-time processing here, if any */
+            return 0;
+
+        case WM_PAINT:
+            hdc = BeginPaint(hwnd, &ps);
+            rc = StretchDIBits(hdc, 0, 0, rpng2_info.width, rpng2_info.height,
+                                    0, 0, rpng2_info.width, rpng2_info.height,
+                                    wimage_data, (BITMAPINFO *)bmih,
+                                    0, SRCCOPY);
+            EndPaint(hwnd, &ps);
+            return 0;
+
+        /* wait for the user to tell us when to quit */
+        case WM_CHAR:
+            switch (wP) {       /* only need one, so ignore repeat count */
+                case 'q':
+                case 'Q':
+                case 0x1B:      /* Esc key */
+                    PostQuitMessage(0);
+            }
+            return 0;
+
+        case WM_LBUTTONDOWN:    /* another way of quitting */
+        case WM_DESTROY:
+            PostQuitMessage(0);
+            return 0;
+    }
+
+    return DefWindowProc(hwnd, iMsg, wP, lP);
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng2-x.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng2-x.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/rpng2-x.c	(revision 107811)
@@ -0,0 +1,2143 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                  rpng2-x.c
+
+   This program decodes and displays PNG files progressively, as if it were
+   a web browser (though the front end is only set up to read from files).
+   It supports gamma correction, user-specified background colors, and user-
+   specified background patterns (for transparent images).  This version is
+   for the X Window System (tested by the author under Unix and by Martin
+   Zinser under OpenVMS; may work under OS/2 with a little tweaking).
+
+   Thanks to Adam Costello and Pieter S. van der Meulen for the "diamond"
+   and "radial waves" patterns, respectively.
+
+   to do (someday, maybe):
+    - fix expose/redraw code:  don't draw entire row if only part exposed
+    - 8-bit (colormapped) X support
+    - finish resizable checkerboard-gradient (sizes 4-128?)
+    - use %.1023s to simplify truncation of title-bar string?
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options; fixed char/uchar mismatch
+    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
+    - 1.11:  added -usleep option for demos; fixed command-line parsing bug
+    - 1.12:  added -pause option for demos and testing
+    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
+    - 1.21:  fixed some small X memory leaks (thanks to François Petitjean)
+    - 1.22:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
+    - 1.23:  added -bgpat 0 mode (std white/gray checkerboard, 8x8 squares)
+    - 1.30:  added -loop option for -bgpat (ifdef FEATURE_LOOP); fixed bpp =
+              24; added support for X resources (thanks to Gerhard Niklasch)
+    - 1.31:  added code to skip unused chunks (thanks to Glenn Randers-Pehrson)
+    - 1.32:  added AMD64/EM64T support (__x86_64__); added basic expose/redraw
+              handling
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed 64-bit typo in readpng2.c; fixed -pause usage description
+    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
+              unexpected-EOF and file-read-error cases; fixed Trace() cut-and-
+              paste bugs
+    - 2.03:  deleted runtime MMX-enabling/disabling and obsolete -mmx* options
+    - 2.04:  Added "void(foo);" statements to quiet pedantic compiler warnings
+             about unused variables (GR-P)
+    - 2.05:  Use nanosleep() instead of usleep(), which is deprecated (GR-P).
+    - 2.06:  check for integer overflow (Glenn R-P)
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2010, 2014-2015, 2017 Greg Roelofs.  All rights
+      reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng2-x"
+#define LONGNAME  "Progressive PNG Viewer for X"
+#define VERSION   "2.04 of 15 June 2014"
+#define RESNAME   "rpng2"       /* our X resource application name */
+#define RESCLASS  "Rpng"       /* our X resource class name */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <setjmp.h>       /* for jmpbuf declaration in readpng2.h */
+#include <time.h>
+#include <math.h>         /* only for PvdM background code */
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xos.h>
+#include <X11/keysym.h>   /* defines XK_* macros */
+
+#if _POSIX_C_SOURCE >= 199309L /* have nanosleep() */
+# undef usleep
+# define usleep(usec) {        \
+   struct timespec ts;         \
+   ts.tv_sec = 0;              \
+   ts.tv_nsec = (usec) * 1000; \
+   nanosleep(&ts, NULL); }
+#  endif
+
+#ifndef usleep /* have neither nanosleep() nor usleep() */
+#  define usleep(x) sleep(((x)+499999)/1000000)
+#endif
+
+#ifdef VMS
+#  include <unistd.h>
+#endif
+
+/* all for PvdM background code: */
+#ifndef PI
+#  define PI             3.141592653589793238
+#endif
+#define PI_2             (PI*0.5)
+#define INV_PI_360       (360.0 / PI)
+#define MAX(a,b)         (a>b?a:b)
+#define MIN(a,b)         (a<b?a:b)
+#define CLIP(a,min,max)  MAX(min,MIN((a),max))
+#define ABS(a)           ((a)<0?-(a):(a))
+#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
+#define ROUNDF(f)        ((int)(f + 0.5))
+
+#define QUIT(e,k) ((e.type == ButtonPress && e.xbutton.button == Button1) ||  \
+                  (e.type == KeyPress &&   /*  v--- or 1 for shifted keys */  \
+                  ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape)))
+
+#define NO_24BIT_MASKS /* undef case not fully written--only for redisplay() */
+
+#define rgb1_max   bg_freq
+#define rgb1_min   bg_gray
+#define rgb2_max   bg_bsat
+#define rgb2_min   bg_brot
+
+/* #define DEBUG */     /* this enables the Trace() macros */
+
+#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+
+
+#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
+                          *  block size corresponds roughly to a download
+                          *  speed 10% faster than theoretical 33.6K maximum
+                          *  (assuming 8 data bits, 1 stop bit and no other
+                          *  overhead) */
+
+/* local prototypes */
+static void rpng2_x_init (void);
+static int  rpng2_x_create_window (void);
+static int  rpng2_x_load_bg_image (void);
+static void rpng2_x_display_row (ulg row);
+static void rpng2_x_finish_display (void);
+static void rpng2_x_redisplay_image (ulg startcol, ulg startrow,
+                                     ulg width, ulg height);
+#ifdef FEATURE_LOOP
+static void rpng2_x_reload_bg_image (void);
+static int  is_number (char *p);
+#endif
+static void rpng2_x_cleanup (void);
+static int  rpng2_x_msb (ulg u32val);
+
+
+static char titlebar[1024], *window_name = titlebar;
+static char *appname = LONGNAME;
+static char *icon_name = PROGNAME;
+static char *res_name = RESNAME;
+static char *res_class = RESCLASS;
+static char *filename;
+static FILE *infile;
+
+static mainprog_info rpng2_info;
+
+static uch inbuf[INBUFSIZE];
+static int incount;
+
+static int pat = 6;        /* must be less than num_bgpat */
+static int bg_image = 0;
+static int bgscale, bgscale_default = 16;
+static ulg bg_rowbytes;
+static uch *bg_data;
+
+int pause_after_pass = FALSE;
+int demo_timing = FALSE;
+ulg usleep_duration = 0L;
+
+static struct rgb_color {
+    uch r, g, b;
+} rgb[] = {
+    {  0,   0,   0},    /*  0:  black */
+    {255, 255, 255},    /*  1:  white */
+    {173, 132,  57},    /*  2:  tan */
+    { 64, 132,   0},    /*  3:  medium green */
+    {189, 117,   1},    /*  4:  gold */
+    {253, 249,   1},    /*  5:  yellow */
+    {  0,   0, 255},    /*  6:  blue */
+    {  0,   0, 120},    /*  7:  medium blue */
+    {255,   0, 255},    /*  8:  magenta */
+    { 64,   0,  64},    /*  9:  dark magenta */
+    {255,   0,   0},    /* 10:  red */
+    { 64,   0,   0},    /* 11:  dark red */
+    {255, 127,   0},    /* 12:  orange */
+    {192,  96,   0},    /* 13:  darker orange */
+    { 24,  60,   0},    /* 14:  dark green-yellow */
+    { 85, 125, 200},    /* 15:  ice blue */
+    {192, 192, 192}     /* 16:  Netscape/Mosaic gray */
+};
+/* not used for now, but should be for error-checking:
+static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
+ */
+
+/*
+    This whole struct is a fairly cheesy way to keep the number of
+    command-line options to a minimum.  The radial-waves background
+    type is a particularly poor fit to the integer elements of the
+    struct...but a few macros and a little fixed-point math will do
+    wonders for ya.
+
+    type bits:
+       F E D C B A 9 8 7 6 5 4 3 2 1 0
+                             | | | | |
+                             | | +-+-+-- 0 = sharp-edged checkerboard
+                             | |         1 = soft diamonds
+                             | |         2 = radial waves
+                             | |       3-7 = undefined
+                             | +-- gradient #2 inverted?
+                             +-- alternating columns inverted?
+ */
+static struct background_pattern {
+    ush type;
+    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
+    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
+} bg[] = {
+    {0,     1,1, 16,16},        /* checkered:  white vs. light gray (basic) */
+    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
+    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
+    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
+    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
+    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
+    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
+    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
+    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
+    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
+    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
+    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
+    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
+    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
+    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
+    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
+    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
+};
+static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
+
+
+/* X-specific variables */
+static char *displayname;
+static XImage *ximage;
+static Display *display;
+static int depth;
+static Visual *visual;
+static XVisualInfo *visual_list;
+static int RShift, GShift, BShift;
+static ulg RMask, GMask, BMask;
+static Window window;
+static GC gc;
+static Colormap colormap;
+
+static int have_nondefault_visual = FALSE;
+static int have_colormap = FALSE;
+static int have_window = FALSE;
+static int have_gc = FALSE;
+
+
+
+
+int main(int argc, char **argv)
+{
+#ifdef sgi
+    char tmpline[80];
+#endif
+    char *p, *bgstr = NULL;
+    int rc, alen, flen;
+    int error = 0;
+    int timing = FALSE;
+    int have_bg = FALSE;
+#ifdef FEATURE_LOOP
+    int loop = FALSE;
+    long loop_interval = -1;            /* seconds (100,000 max) */
+#endif
+    double LUT_exponent;                /* just the lookup table */
+    double CRT_exponent = 2.2;          /* just the monitor */
+    double default_display_exponent;    /* whole display system */
+    XEvent e;
+    KeySym k;
+
+
+    /* First initialize a few things, just to be sure--memset takes care of
+     * default background color (black), booleans (FALSE), pointers (NULL),
+     * etc. */
+
+    displayname = (char *)NULL;
+    filename = (char *)NULL;
+    memset(&rpng2_info, 0, sizeof(mainprog_info));
+
+
+    /* Set the default value for our display-system exponent, i.e., the
+     * product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities. */
+
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        rpng2_info.display_exponent = atof(p);
+    else
+        rpng2_info.display_exponent = default_display_exponent;
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-display", 2)) {
+            if (!*++argv)
+                ++error;
+            else
+                displayname = *argv;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                rpng2_info.display_exponent = atof(*argv);
+                if (rpng2_info.display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    have_bg = TRUE;
+                    bg_image = FALSE;
+                }
+            }
+        } else if (!strncmp(*argv, "-bgpat", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                pat = atoi(*argv);
+                if (pat >= 0 && pat < num_bgpat) {
+                    bg_image = TRUE;
+                    have_bg = FALSE;
+                } else
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-usleep", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                usleep_duration = (ulg)atol(*argv);
+                demo_timing = TRUE;
+            }
+        } else if (!strncmp(*argv, "-pause", 2)) {
+            pause_after_pass = TRUE;
+        } else if (!strncmp(*argv, "-timing", 2)) {
+            timing = TRUE;
+#ifdef FEATURE_LOOP
+        } else if (!strncmp(*argv, "-loop", 2)) {
+            loop = TRUE;
+            if (!argv[1] || !is_number(argv[1]))
+                loop_interval = 2;
+            else {
+                ++argv;
+                loop_interval = atol(*argv);
+                if (loop_interval < 0)
+                    loop_interval = 2;
+                else if (loop_interval > 100000)   /* bit more than one day */
+                    loop_interval = 100000;
+            }
+#endif
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename)
+        ++error;
+
+
+    /* print usage screen if any errors up to this point */
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
+        readpng2_version_info();
+        fprintf(stderr, "\n"
+          "Usage:   ");
+        fprintf(stderr,
+          "%s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+          "        %*s [-usleep dur | -timing] [-pause]\n",
+          PROGNAME, (int)strlen(PROGNAME), " ");
+        fprintf(stderr,
+#ifdef FEATURE_LOOP
+          "        [-loop [sec]]"
+#endif
+          " file.png\n\n");
+        fprintf(stderr,
+          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n",
+          default_display_exponent);
+        fprintf(stderr,
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images; overrides -bgpat\n"
+          "    pat \tdesired background pattern number (0-%d); used with\n"
+          "\t\t  transparent images; overrides -bgcolor\n",
+          num_bgpat-1);
+#ifdef FEATURE_LOOP
+        fprintf(stderr,
+          "    -loop\tloops through background images after initial display\n"
+          "\t\t  is complete (depends on -bgpat)\n"
+          "    sec \tseconds to display each background image (default = 2)\n");
+#endif
+        fprintf(stderr,
+          "    dur \tduration in microseconds to wait after displaying each\n"
+          "\t\t  row (for demo purposes)\n"
+          "    -timing\tenables delay for every block read, to simulate modem\n"
+          "\t\t  download of image (~36 Kbps)\n"
+          "    -pause\tpauses after displaying each pass until mouse clicked\n"
+          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
+          "is displayed) to quit.\n");
+        exit(1);
+    }
+
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
+            fprintf(stderr, PROGNAME
+              ":  [%s] is not a PNG file: incorrect signature\n",
+              filename);
+            ++error;
+        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
+            switch (rc) {
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng2_init() error\n");
+                    break;
+            }
+            ++error;
+        } else {
+            Trace((stderr, "about to call XOpenDisplay()\n"))
+            display = XOpenDisplay(displayname);
+            if (!display) {
+                readpng2_cleanup(&rpng2_info);
+                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
+                  displayname? displayname : "default");
+                ++error;
+            }
+        }
+        if (error)
+            fclose(infile);
+    }
+
+
+    if (error) {
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+        exit(2);
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* set some final rpng2_info variables before entering main data loop */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        rpng2_info.bg_red   = (uch)r;
+        rpng2_info.bg_green = (uch)g;
+        rpng2_info.bg_blue  = (uch)b;
+    } else
+        rpng2_info.need_bgcolor = TRUE;
+
+    rpng2_info.state = kPreInit;
+    rpng2_info.mainprog_init = rpng2_x_init;
+    rpng2_info.mainprog_display_row = rpng2_x_display_row;
+    rpng2_info.mainprog_finish_display = rpng2_x_finish_display;
+
+
+    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
+     * the loop to deal with our first buffer of data (read in above to verify
+     * that the file is a PNG image), then loop through the file and continue
+     * calling the same routine to handle each chunk of data.  It in turn
+     * passes the data to libpng, which will invoke one or more of our call-
+     * backs as decoded data become available.  We optionally call sleep() for
+     * one second per iteration to simulate downloading the image via an analog
+     * modem. */
+
+    for (;;) {
+        Trace((stderr, "about to call readpng2_decode_data()\n"))
+        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
+            ++error;
+        Trace((stderr, "done with readpng2_decode_data()\n"))
+
+        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
+            if (rpng2_info.state == kDone) {
+                Trace((stderr, "done decoding PNG image\n"))
+            } else if (ferror(infile)) {
+                fprintf(stderr, PROGNAME
+                  ":  error while reading PNG image file\n");
+                exit(3);
+            } else if (feof(infile)) {
+                fprintf(stderr, PROGNAME ":  end of file reached "
+                  "(unexpectedly) while reading PNG image file\n");
+                exit(3);
+            } else /* if (error) */ {
+                /* will print error message below */
+            }
+            break;
+        }
+
+        if (timing)
+            sleep(1);
+
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+    }
+
+
+    /* clean up PNG stuff and report any decoding errors */
+
+    fclose(infile);
+    Trace((stderr, "about to call readpng2_cleanup()\n"))
+    readpng2_cleanup(&rpng2_info);
+
+    if (error) {
+        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
+        exit(3);
+    }
+
+
+#ifdef FEATURE_LOOP
+
+    if (loop && bg_image) {
+        Trace((stderr, "entering -loop loop (FEATURE_LOOP)\n"))
+        for (;;) {
+            int i, use_sleep;
+            struct timeval now, then;
+
+            /* get current time and add loop_interval to get target time */
+            if (gettimeofday(&then, NULL) == 0) {
+                then.tv_sec += loop_interval;
+                use_sleep = FALSE;
+            } else
+                use_sleep = TRUE;
+
+            /* do quick check for a quit event but don't wait for it */
+            /* GRR BUG:  should also check for Expose events and redraw... */
+            if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask, &e))
+                if (QUIT(e,k))
+                    break;
+
+            /* generate next background image */
+            if (++pat >= num_bgpat)
+                pat = 0;
+            rpng2_x_reload_bg_image();
+
+            /* wait for timeout, using whatever means are available */
+            if (use_sleep || gettimeofday(&now, NULL) != 0) {
+                for (i = loop_interval;  i > 0;  --i) {
+                    sleep(1);
+                    /* GRR BUG:  also need to check for Expose (and redraw!) */
+                    if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask,
+                        &e) && QUIT(e,k))
+                        break;
+                }
+            } else {
+                /* Y2038 BUG! */
+                if (now.tv_sec < then.tv_sec ||
+                    (now.tv_sec == then.tv_sec && now.tv_usec < then.tv_usec))
+                {
+                    int quit = FALSE;
+                    long seconds_to_go = then.tv_sec - now.tv_sec;
+                    long usleep_usec;
+
+                    /* basically chew up most of remaining loop-interval with
+                     *  calls to sleep(1) interleaved with checks for quit
+                     *  events, but also recalc time-to-go periodically; when
+                     *  done, clean up any remaining time with usleep() call
+                     *  (could also use SIGALRM, but signals are a pain...) */
+                    while (seconds_to_go-- > 1) {
+                        int seconds_done = 0;
+
+                        for (i = seconds_to_go;  i > 0 && !quit;  --i) {
+                            sleep(1);
+                            /* GRR BUG:  need to check for Expose and redraw */
+                            if (XCheckMaskEvent(display, KeyPressMask |
+                                ButtonPressMask, &e) && QUIT(e,k))
+                                quit = TRUE;
+                            if (++seconds_done > 1000)
+                                break;   /* time to redo seconds_to_go meas. */
+                        }
+                        if (quit)
+                            break;
+
+                        /* OK, more than 1000 seconds since last check:
+                         *  correct the time-to-go measurement for drift */
+                        if (gettimeofday(&now, NULL) == 0) {
+                            if (now.tv_sec >= then.tv_sec)
+                                break;
+                            seconds_to_go = then.tv_sec - now.tv_sec;
+                        } else
+                            ++seconds_to_go;  /* restore what we subtracted */
+                    }
+                    if (quit)
+                        break;   /* breaks outer do-loop, skips redisplay */
+
+                    /* since difference between "now" and "then" is already
+                     *  eaten up to within a couple of seconds, don't need to
+                     *  worry about overflow--but might have overshot (neg.) */
+                    if (gettimeofday(&now, NULL) == 0) {
+                        usleep_usec = 1000000L*(then.tv_sec - now.tv_sec) +
+                          then.tv_usec - now.tv_usec;
+                        if (usleep_usec > 0)
+                            usleep((ulg)usleep_usec);
+                    }
+                }
+            }
+
+            /* composite image against new background and display (note that
+             *  we do not take into account the time spent doing this...) */
+            rpng2_x_redisplay_image (0, 0, rpng2_info.width, rpng2_info.height);
+        }
+
+    } else /* FALL THROUGH and do the normal thing */
+
+#endif /* FEATURE_LOOP */
+
+    /* wait for the user to tell us when to quit */
+
+    if (rpng2_info.state >= kWindowInit) {
+        Trace((stderr, "entering final wait-for-quit-event loop\n"))
+        do {
+            XNextEvent(display, &e);
+            if (e.type == Expose) {
+                XExposeEvent *ex = (XExposeEvent *)&e;
+                rpng2_x_redisplay_image (ex->x, ex->y, ex->width, ex->height);
+            }
+        } while (!QUIT(e,k));
+    } else {
+        fprintf(stderr, PROGNAME ":  init callback never called:  probable "
+          "libpng error while decoding PNG metadata\n");
+        exit(4);
+    }
+
+
+    /* we're done:  clean up all image and X resources and go away */
+
+    Trace((stderr, "about to call rpng2_x_cleanup()\n"))
+    rpng2_x_cleanup();
+
+    (void)argc; /* Unused */
+
+    return 0;
+}
+
+
+
+
+
+/* this function is called by readpng2_info_callback() in readpng2.c, which
+ * in turn is called by libpng after all of the pre-IDAT chunks have been
+ * read and processed--i.e., we now have enough info to finish initializing */
+
+static void rpng2_x_init(void)
+{
+    ulg i;
+    ulg rowbytes = rpng2_info.rowbytes;
+
+    Trace((stderr, "beginning rpng2_x_init()\n"))
+    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
+    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
+    Trace((stderr, "  height = %ld\n", rpng2_info.height))
+
+    /* Guard against integer overflow */
+    if (rpng2_info.height > ((size_t)(-1))/rpng2_info.rowbytes) {
+        fprintf(stderr, PROGNAME ":  image_data buffer would be too large\n");
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
+    if (!rpng2_info.image_data) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
+    if (!rpng2_info.row_pointers) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    for (i = 0;  i < rpng2_info.height;  ++i)
+        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
+
+
+    /* do the basic X initialization stuff, make the window, and fill it with
+     * the user-specified, file-specified or default background color or
+     * pattern */
+
+    if (rpng2_x_create_window()) {
+
+        /* GRR TEMPORARY HACK:  this is fundamentally no different from cases
+         * above; libpng should call our error handler to longjmp() back to us
+         * when png_ptr goes away.  If we/it segfault instead, seems like a
+         * libpng bug... */
+
+        /* we're here via libpng callback, so if window fails, clean and bail */
+        readpng2_cleanup(&rpng2_info);
+        rpng2_x_cleanup();
+        exit(2);
+    }
+
+    rpng2_info.state = kWindowInit;
+}
+
+
+
+
+
+static int rpng2_x_create_window(void)
+{
+    ulg bg_red   = rpng2_info.bg_red;
+    ulg bg_green = rpng2_info.bg_green;
+    ulg bg_blue  = rpng2_info.bg_blue;
+    ulg bg_pixel = 0L;
+    ulg attrmask;
+    int need_colormap = FALSE;
+    int screen, pad;
+    uch *xdata;
+    Window root;
+    XEvent e;
+    XGCValues gcvalues;
+    XSetWindowAttributes attr;
+    XTextProperty windowName, *pWindowName = &windowName;
+    XTextProperty iconName, *pIconName = &iconName;
+    XVisualInfo visual_info;
+    XSizeHints *size_hints;
+    XWMHints *wm_hints;
+    XClassHint *class_hints;
+
+
+    Trace((stderr, "beginning rpng2_x_create_window()\n"))
+
+    screen = DefaultScreen(display);
+    depth = DisplayPlanes(display, screen);
+    root = RootWindow(display, screen);
+
+#ifdef DEBUG
+    XSynchronize(display, True);
+#endif
+
+    if (depth != 16 && depth != 24 && depth != 32) {
+        int visuals_matched = 0;
+
+        Trace((stderr, "default depth is %d:  checking other visuals\n",
+          depth))
+
+        /* 24-bit first */
+        visual_info.screen = screen;
+        visual_info.depth = 24;
+        visual_list = XGetVisualInfo(display,
+          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
+        if (visuals_matched == 0) {
+/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
+            fprintf(stderr, "default screen depth %d not supported, and no"
+              " 24-bit visuals found\n", depth);
+            return 2;
+        }
+        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
+          visuals_matched))
+        visual = visual_list[0].visual;
+        depth = visual_list[0].depth;
+/*
+        colormap_size = visual_list[0].colormap_size;
+        visual_class = visual->class;
+        visualID = XVisualIDFromVisual(visual);
+ */
+        have_nondefault_visual = TRUE;
+        need_colormap = TRUE;
+    } else {
+        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
+        visual = visual_info.visual;
+    }
+
+    RMask = visual->red_mask;
+    GMask = visual->green_mask;
+    BMask = visual->blue_mask;
+
+/* GRR:  add/check 8-bit support */
+    if (depth == 8 || need_colormap) {
+        colormap = XCreateColormap(display, root, visual, AllocNone);
+        if (!colormap) {
+            fprintf(stderr, "XCreateColormap() failed\n");
+            return 2;
+        }
+        have_colormap = TRUE;
+        if (depth == 8)
+            bg_image = FALSE;   /* gradient just wastes palette entries */
+    }
+    if (depth == 15 || depth == 16) {
+        RShift = 15 - rpng2_x_msb(RMask);    /* these are right-shifts */
+        GShift = 15 - rpng2_x_msb(GMask);
+        BShift = 15 - rpng2_x_msb(BMask);
+    } else if (depth > 16) {
+        RShift = rpng2_x_msb(RMask) - 7;     /* these are left-shifts */
+        GShift = rpng2_x_msb(GMask) - 7;
+        BShift = rpng2_x_msb(BMask) - 7;
+    }
+    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
+        fprintf(stderr, "rpng2 internal logic error:  negative X shift(s)!\n");
+        return 2;
+    }
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    attr.backing_store = Always;
+    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
+    attrmask = CWBackingStore | CWEventMask;
+    if (have_nondefault_visual) {
+        attr.colormap = colormap;
+        attr.background_pixel = 0;
+        attr.border_pixel = 1;
+        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
+    }
+
+    window = XCreateWindow(display, root, 0, 0, rpng2_info.width,
+      rpng2_info.height, 0, depth, InputOutput, visual, attrmask, &attr);
+
+    if (window == None) {
+        fprintf(stderr, "XCreateWindow() failed\n");
+        return 2;
+    } else
+        have_window = TRUE;
+
+    if (depth == 8)
+        XSetWindowColormap(display, window, colormap);
+
+    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
+        pWindowName = NULL;
+    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
+        pIconName = NULL;
+
+    /* OK if either hints allocation fails; XSetWMProperties() allows NULLs */
+
+    if ((size_hints = XAllocSizeHints()) != NULL) {
+        /* window will not be resizable */
+        size_hints->flags = PMinSize | PMaxSize;
+        size_hints->min_width = size_hints->max_width = (int)rpng2_info.width;
+        size_hints->min_height = size_hints->max_height =
+          (int)rpng2_info.height;
+    }
+
+    if ((wm_hints = XAllocWMHints()) != NULL) {
+        wm_hints->initial_state = NormalState;
+        wm_hints->input = True;
+     /* wm_hints->icon_pixmap = icon_pixmap; */
+        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
+    }
+
+    if ((class_hints = XAllocClassHint()) != NULL) {
+        class_hints->res_name = res_name;
+        class_hints->res_class = res_class;
+    }
+
+    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
+      size_hints, wm_hints, class_hints);
+
+    /* various properties and hints no longer needed; free memory */
+    if (pWindowName)
+       XFree(pWindowName->value);
+    if (pIconName)
+       XFree(pIconName->value);
+    if (size_hints)
+        XFree(size_hints);
+    if (wm_hints)
+       XFree(wm_hints);
+    if (class_hints)
+       XFree(class_hints);
+
+    XMapWindow(display, window);
+
+    gc = XCreateGC(display, window, 0, &gcvalues);
+    have_gc = TRUE;
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the X- and display-specific version of the image.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        xdata = (uch *)malloc(4*rpng2_info.width*rpng2_info.height);
+        pad = 32;
+    } else if (depth == 16) {
+        xdata = (uch *)malloc(2*rpng2_info.width*rpng2_info.height);
+        pad = 16;
+    } else /* depth == 8 */ {
+        xdata = (uch *)malloc(rpng2_info.width*rpng2_info.height);
+        pad = 8;
+    }
+
+    if (!xdata) {
+        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
+        return 4;
+    }
+
+    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
+      (char *)xdata, rpng2_info.width, rpng2_info.height, pad, 0);
+
+    if (!ximage) {
+        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
+        free(xdata);
+        return 3;
+    }
+
+    /* to avoid testing the byte order every pixel (or doubling the size of
+     * the drawing routine with a giant if-test), we arbitrarily set the byte
+     * order to MSBFirst and let Xlib worry about inverting things on little-
+     * endian machines (e.g., Linux/x86, old VAXen, etc.)--this is not the
+     * most efficient approach (the giant if-test would be better), but in
+     * the interest of clarity, we'll take the easy way out... */
+
+    ximage->byte_order = MSBFirst;
+
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color (default is black) or
+    faked "background image" (but latter is disabled if 8-bit; gradients
+    just waste palette entries).
+  ---------------------------------------------------------------------------*/
+
+    if (bg_image)
+        rpng2_x_load_bg_image();    /* resets bg_image if fails */
+
+    if (!bg_image) {
+        if (depth == 24 || depth == 32) {
+            bg_pixel = (bg_red   << RShift) |
+                       (bg_green << GShift) |
+                       (bg_blue  << BShift);
+        } else if (depth == 16) {
+            bg_pixel = (((bg_red   << 8) >> RShift) & RMask) |
+                       (((bg_green << 8) >> GShift) & GMask) |
+                       (((bg_blue  << 8) >> BShift) & BMask);
+        } else /* depth == 8 */ {
+
+            /* GRR:  add 8-bit support */
+
+        }
+        XSetForeground(display, gc, bg_pixel);
+        XFillRectangle(display, window, gc, 0, 0, rpng2_info.width,
+          rpng2_info.height);
+    }
+
+/*---------------------------------------------------------------------------
+    Wait for first Expose event to do any drawing, then flush and return.
+  ---------------------------------------------------------------------------*/
+
+    do
+        XNextEvent(display, &e);
+    while (e.type != Expose || e.xexpose.count);
+
+    XFlush(display);
+
+    return 0;
+
+} /* end function rpng2_x_create_window() */
+
+
+
+
+
+static int rpng2_x_load_bg_image(void)
+{
+    uch *src;
+    char *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max;
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    int ximage_rowbytes = ximage->bytes_per_line;
+    ulg i, row;
+    ulg pixel;
+
+/*---------------------------------------------------------------------------
+    Allocate buffer for fake background image to be used with transparent
+    images; if this fails, revert to plain background color.
+  ---------------------------------------------------------------------------*/
+
+    bg_rowbytes = 3 * rpng2_info.width;
+    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
+    if (!bg_data) {
+        fprintf(stderr, PROGNAME
+          ":  unable to allocate memory for background image\n");
+        bg_image = 0;
+        return 1;
+    }
+
+    bgscale = (pat == 0)? 8 : bgscale_default;
+    yidx_max = bgscale - 1;
+
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            even_odd_vert = (int)((row / bgscale) & 1);
+
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (int)((i / bgscale) & 1);
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {        /* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {                    /* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;       /* not inverted or */
+                        *dest++ = g2;       /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;   /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 1) {
+
+        hmax = (bgscale-1)/2;   /* half the max weight of a color */
+        max = 2*hmax;           /* the max weight of a color */
+
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = (int)(i % bgscale);
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+
+        fprintf(stderr, "%s:  computing radial background...",
+          PROGNAME);
+        fflush(stderr);
+
+        hh = (int)(rpng2_info.height / 2);
+        hw = (int)(rpng2_info.width / 2);
+
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = (int)(row - hh);
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = (int)(i - hw);
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+        fprintf(stderr, "done.\n");
+        fflush(stderr);
+    }
+
+/*---------------------------------------------------------------------------
+    Blast background image to display buffer before beginning PNG decode.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        int bpp = ximage->bits_per_pixel;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            src = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (bpp == 32) {    /* slightly optimized version */
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
+                    /*           (probably need to use RShift, RMask, etc.) */
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            src = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = ((ush)(*src) << 8);  ++src;
+                green = ((ush)(*src) << 8);  ++src;
+                blue  = ((ush)(*src) << 8);  ++src;
+                pixel = ((red   >> RShift) & RMask) |
+                        ((green >> GShift) & GMask) |
+                        ((blue  >> BShift) & BMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = (char)((pixel >>  8) & 0xff);
+                *dest++ = (char)( pixel        & 0xff);
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    XPutImage(display, window, gc, ximage, 0, 0, 0, 0, rpng2_info.width,
+      rpng2_info.height);
+
+    return 0;
+
+} /* end function rpng2_x_load_bg_image() */
+
+
+
+
+
+static void rpng2_x_display_row(ulg row)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL;
+    char *dest;
+    uch r, g, b, a;
+    int ximage_rowbytes = ximage->bytes_per_line;
+    ulg i, pixel;
+    static int rows=0, prevpass=(-1);
+    static ulg firstrow;
+
+/*---------------------------------------------------------------------------
+    rows and firstrow simply track how many rows (and which ones) have not
+    yet been displayed; alternatively, we could call XPutImage() for every
+    row and not bother with the records-keeping.
+  ---------------------------------------------------------------------------*/
+
+    Trace((stderr, "beginning rpng2_x_display_row()\n"))
+
+    if (rpng2_info.pass != prevpass) {
+        if (pause_after_pass && rpng2_info.pass > 0) {
+            XEvent e;
+            KeySym k;
+
+            fprintf(stderr,
+              "%s:  end of pass %d of 7; click in image window to continue\n",
+              PROGNAME, prevpass + 1);
+            do
+                XNextEvent(display, &e);
+            while (!QUIT(e,k));
+        }
+        fprintf(stderr, "%s:  pass %d of 7\r", PROGNAME, rpng2_info.pass + 1);
+        fflush(stderr);
+        prevpass = rpng2_info.pass;
+    }
+
+    if (rows == 0)
+        firstrow = row;   /* first row that is not yet displayed */
+
+    ++rows;   /* count of rows received but not yet displayed */
+
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct, the lack of an outer loop
+    (over rows) and moving the XPutImage() call outside the "if (depth)"
+    tests, this routine is identical to rpng_x_display_image() in the non-
+    progressive version of the program.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        int bpp = ximage->bits_per_pixel;
+
+        src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+        if (bg_image)
+            src2 = bg_data + row*bg_rowbytes;
+        dest = ximage->data + row*ximage_rowbytes;
+        if (rpng2_info.channels == 3) {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = *src++;
+                green = *src++;
+                blue  = *src++;
+                pixel = (red   << RShift) |
+                        (green << GShift) |
+                        (blue  << BShift);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                if (bpp == 32) {
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                } else {
+                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
+                    /*           (probably need to use RShift, RMask, etc.) */
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+        } else /* if (rpng2_info.channels == 4) */ {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (bg_image) {
+                    bg_red   = *src2++;
+                    bg_green = *src2++;
+                    bg_blue  = *src2++;
+                }
+                if (a == 255) {
+                    red   = r;
+                    green = g;
+                    blue  = b;
+                } else if (a == 0) {
+                    red   = bg_red;
+                    green = bg_green;
+                    blue  = bg_blue;
+                } else {
+                    /* this macro (from png.h) composites the foreground
+                     * and background values and puts the result into the
+                     * first argument */
+                    alpha_composite(red,   r, a, bg_red);
+                    alpha_composite(green, g, a, bg_green);
+                    alpha_composite(blue,  b, a, bg_blue);
+                }
+                pixel = (red   << RShift) |
+                        (green << GShift) |
+                        (blue  << BShift);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                if (bpp == 32) {
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                } else {
+                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
+                    /*           (probably need to use RShift, RMask, etc.) */
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        src = rpng2_info.row_pointers[row];
+        if (bg_image)
+            src2 = bg_data + row*bg_rowbytes;
+        dest = ximage->data + row*ximage_rowbytes;
+        if (rpng2_info.channels == 3) {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = ((ush)(*src) << 8);
+                ++src;
+                green = ((ush)(*src) << 8);
+                ++src;
+                blue  = ((ush)(*src) << 8);
+                ++src;
+                pixel = ((red   >> RShift) & RMask) |
+                        ((green >> GShift) & GMask) |
+                        ((blue  >> BShift) & BMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = (char)((pixel >>  8) & 0xff);
+                *dest++ = (char)( pixel        & 0xff);
+            }
+        } else /* if (rpng2_info.channels == 4) */ {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (bg_image) {
+                    bg_red   = *src2++;
+                    bg_green = *src2++;
+                    bg_blue  = *src2++;
+                }
+                if (a == 255) {
+                    red   = ((ush)r << 8);
+                    green = ((ush)g << 8);
+                    blue  = ((ush)b << 8);
+                } else if (a == 0) {
+                    red   = ((ush)bg_red   << 8);
+                    green = ((ush)bg_green << 8);
+                    blue  = ((ush)bg_blue  << 8);
+                } else {
+                    /* this macro (from png.h) composites the foreground
+                     * and background values and puts the result back into
+                     * the first argument (== fg byte here:  safe) */
+                    alpha_composite(r, r, a, bg_red);
+                    alpha_composite(g, g, a, bg_green);
+                    alpha_composite(b, b, a, bg_blue);
+                    red   = ((ush)r << 8);
+                    green = ((ush)g << 8);
+                    blue  = ((ush)b << 8);
+                }
+                pixel = ((red   >> RShift) & RMask) |
+                        ((green >> GShift) & GMask) |
+                        ((blue  >> BShift) & BMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = (char)((pixel >>  8) & 0xff);
+                *dest++ = (char)( pixel        & 0xff);
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+
+/*---------------------------------------------------------------------------
+    Display after every 16 rows or when on one of last two rows.  (Region
+    may include previously displayed lines due to interlacing--i.e., not
+    contiguous.  Also, second-to-last row is final one in interlaced images
+    with odd number of rows.)  For demos, flush (and delay) after every 16th
+    row so "sparse" passes don't go twice as fast.
+  ---------------------------------------------------------------------------*/
+
+    if (demo_timing && (row - firstrow >= 16 || row >= rpng2_info.height-2)) {
+        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
+          (int)firstrow, rpng2_info.width, row - firstrow + 1);
+        XFlush(display);
+        rows = 0;
+        usleep(usleep_duration);
+    } else
+    if (!demo_timing && ((rows & 0xf) == 0 || row >= rpng2_info.height-2)) {
+        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
+          (int)firstrow, rpng2_info.width, row - firstrow + 1);
+        XFlush(display);
+        rows = 0;
+    }
+
+}
+
+
+
+
+
+static void rpng2_x_finish_display(void)
+{
+    Trace((stderr, "beginning rpng2_x_finish_display()\n"))
+
+    /* last row has already been displayed by rpng2_x_display_row(), so we
+     * have nothing to do here except set a flag and let the user know that
+     * the image is done */
+
+    rpng2_info.state = kDone;
+    printf(
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
+    fflush(stdout);
+}
+
+
+
+
+
+static void rpng2_x_redisplay_image(ulg startcol, ulg startrow,
+                                    ulg width, ulg height)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL;
+    char *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow = 0;
+    ulg pixel;
+    int ximage_rowbytes = ximage->bytes_per_line;
+
+
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      rpng2_info.channels))
+    Trace((stderr, "   (width = %ld, rowbytes = %d, ximage_rowbytes = %d)\n",
+      rpng2_info.width, rpng2_info.rowbytes, ximage_rowbytes))
+    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
+    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
+      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
+
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct and of src2 (for background
+    image), this routine is identical to rpng_x_display_image() in the non-
+    progressive version of the program--for the simple reason that redisplay
+    of the image against a new background happens after the image is fully
+    decoded and therefore is, by definition, non-progressive.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        int bpp = ximage->bits_per_pixel;
+
+        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
+            src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+            if (bg_image)
+                src2 = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (rpng2_info.channels == 3) {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift, RMask, etc.) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* GRR BUG */
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift/RMask/etc. here, too) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#endif
+                }
+
+            } else /* if (rpng2_info.channels == 4) */ {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (bg_image) {
+                        bg_red   = *src2++;
+                        bg_green = *src2++;
+                        bg_blue  = *src2++;
+                    }
+                    if (a == 255) {
+                        red   = r;
+                        green = g;
+                        blue  = b;
+                    } else if (a == 0) {
+                        red   = bg_red;
+                        green = bg_green;
+                        blue  = bg_blue;
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result into the
+                         * first argument */
+                        alpha_composite(red,   r, a, bg_red);
+                        alpha_composite(green, g, a, bg_green);
+                        alpha_composite(blue,  b, a, bg_blue);
+                    }
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift, RMask, etc.) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* GRR BUG */
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift/RMask/etc. here, too) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#endif
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, rpng2_info.width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
+            src = rpng2_info.row_pointers[row];
+            if (bg_image)
+                src2 = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (rpng2_info.channels == 3) {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = ((ush)(*src) << 8);
+                    ++src;
+                    green = ((ush)(*src) << 8);
+                    ++src;
+                    blue  = ((ush)(*src) << 8);
+                    ++src;
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else /* if (rpng2_info.channels == 4) */ {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (bg_image) {
+                        bg_red   = *src2++;
+                        bg_green = *src2++;
+                        bg_blue  = *src2++;
+                    }
+                    if (a == 255) {
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    } else if (a == 0) {
+                        red   = ((ush)bg_red   << 8);
+                        green = ((ush)bg_green << 8);
+                        blue  = ((ush)bg_blue  << 8);
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result back into
+                         * the first argument (== fg byte here:  safe) */
+                        alpha_composite(r, r, a, bg_red);
+                        alpha_composite(g, g, a, bg_green);
+                        alpha_composite(b, b, a, bg_blue);
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    }
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, rpng2_info.width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    Trace((stderr, "calling final XPutImage()\n"))
+    if (lastrow < startrow+height) {
+        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+          (int)lastrow, rpng2_info.width, rpng2_info.height-lastrow);
+        XFlush(display);
+    }
+
+    (void)startcol;
+    (void)width;
+
+} /* end function rpng2_x_redisplay_image() */
+
+
+
+
+
+#ifdef FEATURE_LOOP
+
+static void rpng2_x_reload_bg_image(void)
+{
+    char *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max;
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    ulg i, row;
+
+
+    bgscale = (pat == 0)? 8 : bgscale_default;
+    yidx_max = bgscale - 1;
+
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            even_odd_vert = (int)((row / bgscale) & 1);
+
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (int)((i / bgscale) & 1);
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {        /* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {                    /* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;       /* not inverted or */
+                        *dest++ = g2;       /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;   /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 1) {
+
+        hmax = (bgscale-1)/2;   /* half the max weight of a color */
+        max = 2*hmax;           /* the max weight of a color */
+
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = (int)(i % bgscale);
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+
+        hh = (int)(rpng2_info.height / 2);
+        hw = (int)(rpng2_info.width / 2);
+
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = (int)(row - hh);
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = (int)(i - hw);
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+    }
+
+} /* end function rpng2_x_reload_bg_image() */
+
+
+
+
+
+static int is_number(char *p)
+{
+    while (*p) {
+        if (!isdigit(*p))
+            return FALSE;
+        ++p;
+    }
+    return TRUE;
+}
+
+#endif /* FEATURE_LOOP */
+
+
+
+
+
+static void rpng2_x_cleanup(void)
+{
+    if (bg_image && bg_data) {
+        free(bg_data);
+        bg_data = NULL;
+    }
+
+    if (rpng2_info.image_data) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+    }
+
+    if (rpng2_info.row_pointers) {
+        free(rpng2_info.row_pointers);
+        rpng2_info.row_pointers = NULL;
+    }
+
+    if (ximage) {
+        if (ximage->data) {
+            free(ximage->data);           /* we allocated it, so we free it */
+            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
+        }
+        XDestroyImage(ximage);
+        ximage = NULL;
+    }
+
+    if (have_gc)
+        XFreeGC(display, gc);
+
+    if (have_window)
+        XDestroyWindow(display, window);
+
+    if (have_colormap)
+        XFreeColormap(display, colormap);
+
+    if (have_nondefault_visual)
+        XFree(visual_list);
+}
+
+
+
+
+
+static int rpng2_x_msb(ulg u32val)
+{
+    int i;
+
+    for (i = 31;  i >= 0;  --i) {
+        if (u32val & 0x80000000L)
+            break;
+        u32val <<= 1;
+    }
+    return i;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/wpng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/wpng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/wpng.c	(revision 107811)
@@ -0,0 +1,865 @@
+/*---------------------------------------------------------------------------
+
+   wpng - simple PNG-writing program                                 wpng.c
+
+   This program converts certain NetPBM binary files (grayscale and RGB,
+   maxval = 255) to PNG.  Non-interlaced PNGs are written progressively;
+   interlaced PNGs are read and written in one memory-intensive blast.
+
+   Thanks to Jean-loup Gailly for providing the necessary trick to read
+   interactive text from the keyboard while stdin is redirected.  Thanks
+   to Cosmin Truta for Cygwin fixes.
+
+   NOTE:  includes provisional support for PNM type "8" (portable alphamap)
+          images, presumed to be a 32-bit interleaved RGBA format; no pro-
+          vision for possible interleaved grayscale+alpha (16-bit) format.
+          THIS IS UNLIKELY TO BECOME AN OFFICIAL NETPBM ALPHA FORMAT!
+
+   to do:
+    - delete output file if quit before calling any writepng routines
+    - process backspace with -text option under DOS/Win? (currently get ^H)
+
+  ---------------------------------------------------------------------------
+
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options
+    - 1.03:  removed extraneous character from usage screen; fixed bug in
+              command-line parsing
+    - 1.04:  fixed DOS/OS2/Win32 detection, including partial Cygwin fix
+              (see http://home.att.net/~perlspinr/diffs/GregBook_cygwin.diff)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  check for integer overflow (Glenn R-P)
+
+        [REPORTED BUG (win32 only):  "contrib/gregbook/wpng.c - cmd line
+         dose not work!  In order to do something useful I needed to redirect
+         both input and output, with cygwin and with bcc32 as well.  Under
+         Linux, the same wpng appears to work fine.  I don't know what is
+         the problem."]
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "wpng"
+#define VERSION   "2.00 of 2 June 2007"
+#define APPNAME   "Simple PGM/PPM/PAM to PNG Converter"
+
+#if defined(__MSDOS__) || defined(__OS2__)
+#  define DOS_OS2_W32
+#elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
+#  ifndef __GNUC__   /* treat Win32 native ports of gcc as Unix environments */
+#    define DOS_OS2_W32
+#  endif
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <setjmp.h>     /* for jmpbuf declaration in writepng.h */
+#include <time.h>
+
+#ifdef DOS_OS2_W32
+#  include <io.h>       /* for isatty(), setmode() prototypes */
+#  include <fcntl.h>    /* O_BINARY for fdopen() without text translation */
+#  ifdef __EMX__
+#    ifndef getch
+#      define getch() _read_kbd(0, 1, 0)    /* need getche() */
+#    endif
+#  else /* !__EMX__ */
+#    ifdef __GO32__
+#      include <pc.h>
+#      define getch() getkey()  /* GRR:  need getche() */
+#    else
+#      include <conio.h>        /* for getche() console input */
+#    endif
+#  endif /* ?__EMX__ */
+#  define FGETS(buf,len,stream)  dos_kbd_gets(buf,len)
+#else
+#  include <unistd.h>           /* for isatty() prototype */
+#  define FGETS fgets
+#endif
+
+/* #define DEBUG  :  this enables the Trace() macros */
+
+/* #define FORBID_LATIN1_CTRL  :  this requires the user to re-enter any
+   text that includes control characters discouraged by the PNG spec; text
+   that includes an escape character (27) must be re-entered regardless */
+
+#include "writepng.h"   /* typedefs, common macros, writepng prototypes */
+
+
+
+/* local prototypes */
+
+static int  wpng_isvalid_latin1(uch *p, int len);
+static void wpng_cleanup(void);
+
+#ifdef DOS_OS2_W32
+   static char *dos_kbd_gets(char *buf, int len);
+#endif
+
+
+
+static mainprog_info wpng_info;   /* lone global */
+
+
+
+int main(int argc, char **argv)
+{
+#ifndef DOS_OS2_W32
+    FILE *keybd;
+#endif
+#ifdef sgi
+    FILE *tmpfile;      /* or we could just use keybd, since no overlap */
+    char tmpline[80];
+#endif
+    char *inname = NULL, outname[256];
+    char *p, pnmchar, pnmline[256];
+    char *bgstr, *textbuf = NULL;
+    ulg rowbytes;
+    int rc, len = 0;
+    int error = 0;
+    int text = FALSE;
+    int maxval;
+    double LUT_exponent;                /* just the lookup table */
+    double CRT_exponent = 2.2;          /* just the monitor */
+    double default_display_exponent;    /* whole display system */
+    double default_gamma = 0.0;
+
+
+    wpng_info.infile = NULL;
+    wpng_info.outfile = NULL;
+    wpng_info.image_data = NULL;
+    wpng_info.row_pointers = NULL;
+    wpng_info.filter = FALSE;
+    wpng_info.interlaced = FALSE;
+    wpng_info.have_bg = FALSE;
+    wpng_info.have_time = FALSE;
+    wpng_info.have_text = 0;
+    wpng_info.gamma = 0.0;
+
+
+    /* First get the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  If the PNM image
+     * looks correct on the user's display system, its file gamma is the
+     * inverse of this value.  (Note that this is not an exhaustive list
+     * of LUT values--e.g., OpenStep has a lot of weird ones--but it should
+     * cover 99% of the current possibilities.  This section must ensure
+     * that default_display_exponent is positive.) */
+
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    tmpfile = fopen("/etc/config/system.glGammaVal", "r");
+    if (tmpfile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, tmpfile);
+        fclose(tmpfile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL) {
+        double exponent = atof(p);
+
+        if (exponent > 0.0)
+            default_gamma = 1.0 / exponent;
+    }
+
+    if (default_gamma == 0.0)
+        default_gamma = 1.0 / default_display_exponent;
+
+
+    /* Now parse the command line for options and the PNM filename. */
+
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-i", 2)) {
+            wpng_info.interlaced = TRUE;
+        } else if (!strncmp(*argv, "-time", 3)) {
+            wpng_info.modtime = time(NULL);
+            wpng_info.have_time = TRUE;
+        } else if (!strncmp(*argv, "-text", 3)) {
+            text = TRUE;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                wpng_info.gamma = atof(*argv);
+                if (wpng_info.gamma <= 0.0)
+                    ++error;
+                else if (wpng_info.gamma > 1.01)
+                    fprintf(stderr, PROGNAME
+                      " warning:  file gammas are usually less than 1.0\n");
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    unsigned r, g, b;  /* this way quiets compiler warnings */
+
+                    sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+                    wpng_info.bg_red   = (uch)r;
+                    wpng_info.bg_green = (uch)g;
+                    wpng_info.bg_blue  = (uch)b;
+                    wpng_info.have_bg = TRUE;
+                }
+            }
+        } else {
+            if (**argv != '-') {
+                inname = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+
+    /* open the input and output files, or register an error and abort */
+
+    if (!inname) {
+        if (isatty(0)) {
+            fprintf(stderr, PROGNAME
+              ":  must give input filename or provide image data via stdin\n");
+            ++error;
+        } else {
+#ifdef DOS_OS2_W32
+            /* some buggy C libraries require BOTH setmode() and fdopen(bin) */
+            setmode(fileno(stdin), O_BINARY);
+            setmode(fileno(stdout), O_BINARY);
+#endif
+            if ((wpng_info.infile = fdopen(fileno(stdin), "rb")) == NULL) {
+                fprintf(stderr, PROGNAME
+                  ":  unable to reopen stdin in binary mode\n");
+                ++error;
+            } else
+            if ((wpng_info.outfile = fdopen(fileno(stdout), "wb")) == NULL) {
+                fprintf(stderr, PROGNAME
+                  ":  unable to reopen stdout in binary mode\n");
+                fclose(wpng_info.infile);
+                ++error;
+            } else
+                wpng_info.filter = TRUE;
+        }
+    } else if ((len = strlen(inname)) > 250) {
+        fprintf(stderr, PROGNAME ":  input filename is too long [%d chars]\n",
+          len);
+        ++error;
+    } else if (!(wpng_info.infile = fopen(inname, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open input file [%s]\n", inname);
+        ++error;
+    }
+
+    if (!error) {
+        fgets(pnmline, 256, wpng_info.infile);
+        if (pnmline[0] != 'P' || ((pnmchar = pnmline[1]) != '5' &&
+            pnmchar != '6' && pnmchar != '8'))
+        {
+            fprintf(stderr, PROGNAME
+              ":  input file [%s] is not a binary PGM, PPM or PAM file\n",
+              inname);
+            ++error;
+        } else {
+            wpng_info.pnmtype = (int)(pnmchar - '0');
+            if (wpng_info.pnmtype != 8)
+                wpng_info.have_bg = FALSE;  /* no need for bg if opaque */
+            do {
+                fgets(pnmline, 256, wpng_info.infile);  /* lose any comments */
+            } while (pnmline[0] == '#');
+            sscanf(pnmline, "%ld %ld", &wpng_info.width, &wpng_info.height);
+            do {
+                fgets(pnmline, 256, wpng_info.infile);  /* more comment lines */
+            } while (pnmline[0] == '#');
+            sscanf(pnmline, "%d", &maxval);
+            if (wpng_info.width <= 0L || wpng_info.height <= 0L ||
+                maxval != 255)
+            {
+                fprintf(stderr, PROGNAME
+                  ":  only positive width/height, maxval == 255 allowed \n");
+                ++error;
+            }
+            wpng_info.sample_depth = 8;  /* <==> maxval 255 */
+
+            if (!wpng_info.filter) {
+                /* make outname from inname */
+                if ((p = strrchr(inname, '.')) == NULL ||
+                    (p - inname) != (len - 4))
+                {
+                    strcpy(outname, inname);
+                    strcpy(outname+len, ".png");
+                } else {
+                    len -= 4;
+                    strncpy(outname, inname, len);
+                    strcpy(outname+len, ".png");
+                }
+                /* check if outname already exists; if not, open */
+                if ((wpng_info.outfile = fopen(outname, "rb")) != NULL) {
+                    fprintf(stderr, PROGNAME ":  output file exists [%s]\n",
+                      outname);
+                    fclose(wpng_info.outfile);
+                    ++error;
+                } else if (!(wpng_info.outfile = fopen(outname, "wb"))) {
+                    fprintf(stderr, PROGNAME ":  can't open output file [%s]\n",
+                      outname);
+                    ++error;
+                }
+            }
+        }
+        if (error) {
+            fclose(wpng_info.infile);
+            wpng_info.infile = NULL;
+            if (wpng_info.filter) {
+                fclose(wpng_info.outfile);
+                wpng_info.outfile = NULL;
+            }
+        }
+    }
+
+
+    /* if we had any errors, print usage and die horrible death...arrr! */
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, APPNAME);
+        writepng_version_info();
+        fprintf(stderr, "\n"
+"Usage:  %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] pnmfile\n"
+"or: ... | %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] | ...\n"
+         "    exp \ttransfer-function exponent (``gamma'') of the image in\n"
+         "\t\t  floating-point format (e.g., ``%.5f''); if image looks\n"
+         "\t\t  correct on given display system, image gamma is equal to\n"
+         "\t\t  inverse of display-system exponent, i.e., 1 / (LUT * CRT)\n"
+         "\t\t  (where LUT = lookup-table exponent and CRT = CRT exponent;\n"
+         "\t\t  first varies, second is usually 2.2, all are positive)\n"
+         "    bg  \tdesired background color for alpha-channel images, in\n"
+         "\t\t  7-character hex RGB format (e.g., ``#ff7700'' for orange:\n"
+         "\t\t  same as HTML colors)\n"
+         "    -text\tprompt interactively for text info (tEXt chunks)\n"
+         "    -time\tinclude a tIME chunk (last modification time)\n"
+         "    -interlace\twrite interlaced PNG image\n"
+         "\n"
+"pnmfile or stdin must be a binary PGM (`P5'), PPM (`P6') or (extremely\n"
+"unofficial and unsupported!) PAM (`P8') file.  Currently it is required\n"
+"to have maxval == 255 (i.e., no scaling).  If pnmfile is specified, it\n"
+"is converted to the corresponding PNG file with the same base name but a\n"
+"``.png'' extension; files read from stdin are converted and sent to stdout.\n"
+"The conversion is progressive (low memory usage) unless interlacing is\n"
+"requested; in that case the whole image will be buffered in memory and\n"
+"written in one call.\n"
+         "\n", PROGNAME, PROGNAME, default_gamma);
+        exit(1);
+    }
+
+
+    /* prepare the text buffers for libpng's use; note that even though
+     * PNG's png_text struct includes a length field, we don't have to fill
+     * it out */
+
+    if (text &&
+#ifndef DOS_OS2_W32
+        (keybd = fdopen(fileno(stderr), "r")) != NULL &&
+#endif
+        (textbuf = (char *)malloc((5 + 9)*75)) != NULL)
+    {
+        int i, valid, result;
+
+        fprintf(stderr,
+          "Enter text info (no more than 72 characters per line);\n");
+        fprintf(stderr, "to skip a field, hit the <Enter> key.\n");
+        /* note:  just <Enter> leaves len == 1 */
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_TITLE_OFFSET;
+            fprintf(stderr, "  Title: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.title = p;
+                wpng_info.have_text |= TEXT_TITLE;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_TITLE;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_TITLE;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_AUTHOR_OFFSET;
+            fprintf(stderr, "  Author: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.author = p;
+                wpng_info.have_text |= TEXT_AUTHOR;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_AUTHOR;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_AUTHOR;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_DESC_OFFSET;
+            fprintf(stderr, "  Description (up to 9 lines):\n");
+            for (i = 1;  i < 10;  ++i) {
+                fprintf(stderr, "    [%d] ", i);
+                fflush(stderr);
+                if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1)
+                    p += len;   /* now points at NULL; char before is newline */
+                else
+                    break;
+            }
+            if ((len = p - (textbuf + TEXT_DESC_OFFSET)) > 1) {
+                if (p[-1] == '\n') {
+                    p[-1] = '\0';
+                    --len;
+                }
+                wpng_info.desc = textbuf + TEXT_DESC_OFFSET;
+                wpng_info.have_text |= TEXT_DESC;
+                p = textbuf + TEXT_DESC_OFFSET;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_DESC;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_DESC;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_COPY_OFFSET;
+            fprintf(stderr, "  Copyright: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.copyright = p;
+                wpng_info.have_text |= TEXT_COPY;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_COPY;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_COPY;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_EMAIL_OFFSET;
+            fprintf(stderr, "  E-mail: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.email = p;
+                wpng_info.have_text |= TEXT_EMAIL;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_EMAIL;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_EMAIL;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_URL_OFFSET;
+            fprintf(stderr, "  URL: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.url = p;
+                wpng_info.have_text |= TEXT_URL;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_URL;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_URL;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+
+#ifndef DOS_OS2_W32
+        fclose(keybd);
+#endif
+
+    } else if (text) {
+        fprintf(stderr, PROGNAME ":  unable to allocate memory for text\n");
+        text = FALSE;
+        wpng_info.have_text = 0;
+    }
+
+
+    /* allocate libpng stuff, initialize transformations, write pre-IDAT data */
+
+    if ((rc = writepng_init(&wpng_info)) != 0) {
+        switch (rc) {
+            case 2:
+                fprintf(stderr, PROGNAME
+                  ":  libpng initialization problem (longjmp)\n");
+                break;
+            case 4:
+                fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                break;
+            case 11:
+                fprintf(stderr, PROGNAME
+                  ":  internal logic error (unexpected PNM type)\n");
+                break;
+            default:
+                fprintf(stderr, PROGNAME
+                  ":  unknown writepng_init() error\n");
+                break;
+        }
+        exit(rc);
+    }
+
+
+    /* free textbuf, since it's a completely local variable and all text info
+     * has just been written to the PNG file */
+
+    if (text && textbuf) {
+        free(textbuf);
+        textbuf = NULL;
+    }
+
+
+    /* calculate rowbytes on basis of image type; note that this becomes much
+     * more complicated if we choose to support PBM type, ASCII PNM types, or
+     * 16-bit-per-sample binary data [currently not an official NetPBM type] */
+
+    if (wpng_info.pnmtype == 5)
+        rowbytes = wpng_info.width;
+    else if (wpng_info.pnmtype == 6)
+        rowbytes = wpng_info.width * 3;
+    else /* if (wpng_info.pnmtype == 8) */
+        rowbytes = wpng_info.width * 4;
+
+
+    /* read and write the image, either in its entirety (if writing interlaced
+     * PNG) or row by row (if non-interlaced) */
+
+    fprintf(stderr, "Encoding image data...\n");
+    fflush(stderr);
+
+    if (wpng_info.interlaced) {
+        long i;
+        ulg bytes;
+        ulg image_bytes;
+
+        /* Guard against integer overflow */
+        if (wpng_info_height > ((size_t)(-1)/rowbytes ||
+            wpng_info_height > ((ulg)(-1)/rowbytes) {
+            fprintf(stderr, PROGNAME ":  image_data buffer too large\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+
+        image_bytes = rowbytes * wpng_info.height;
+
+        wpng_info.image_data = (uch *)malloc(image_bytes);
+        wpng_info.row_pointers = (uch **)malloc(wpng_info.height*sizeof(uch *));
+        if (wpng_info.image_data == NULL || wpng_info.row_pointers == NULL) {
+            fprintf(stderr, PROGNAME ":  insufficient memory for image data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+        for (i = 0;  i < wpng_info.height;  ++i)
+            wpng_info.row_pointers[i] = wpng_info.image_data + i*rowbytes;
+        bytes = fread(wpng_info.image_data, 1, image_bytes, wpng_info.infile);
+        if (bytes != image_bytes) {
+            fprintf(stderr, PROGNAME ":  expected %lu bytes, got %lu bytes\n",
+              image_bytes, bytes);
+            fprintf(stderr, "  (continuing anyway)\n");
+        }
+        if (writepng_encode_image(&wpng_info) != 0) {
+            fprintf(stderr, PROGNAME
+              ":  libpng problem (longjmp) while writing image data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+
+    } else /* not interlaced:  write progressively (row by row) */ {
+        long j;
+        ulg bytes;
+
+        wpng_info.image_data = (uch *)malloc(rowbytes);
+        if (wpng_info.image_data == NULL) {
+            fprintf(stderr, PROGNAME ":  insufficient memory for row data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+        error = 0;
+        for (j = wpng_info.height;  j > 0L;  --j) {
+            bytes = fread(wpng_info.image_data, 1, rowbytes, wpng_info.infile);
+            if (bytes != rowbytes) {
+                fprintf(stderr, PROGNAME
+                  ":  expected %lu bytes, got %lu bytes (row %ld)\n", rowbytes,
+                  bytes, wpng_info.height-j);
+                ++error;
+                break;
+            }
+            if (writepng_encode_row(&wpng_info) != 0) {
+                fprintf(stderr, PROGNAME
+                  ":  libpng problem (longjmp) while writing row %ld\n",
+                  wpng_info.height-j);
+                ++error;
+                break;
+            }
+        }
+        if (error) {
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+        if (writepng_encode_finish(&wpng_info) != 0) {
+            fprintf(stderr, PROGNAME ":  error on final libpng call\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+    }
+
+
+    /* OK, we're done (successfully):  clean up all resources and quit */
+
+    fprintf(stderr, "Done.\n");
+    fflush(stderr);
+
+    writepng_cleanup(&wpng_info);
+    wpng_cleanup();
+
+    return 0;
+}
+
+
+
+
+
+static int wpng_isvalid_latin1(uch *p, int len)
+{
+    int i, result = -1;
+
+    for (i = 0;  i < len;  ++i) {
+        if (p[i] == 10 || (p[i] > 31 && p[i] < 127) || p[i] > 160)
+            continue;           /* character is completely OK */
+        if (result < 0 || (p[result] != 27 && p[i] == 27))
+            result = i;         /* mark location of first questionable one */
+    }                           /*  or of first escape character (bad) */
+
+    return result;
+}
+
+
+
+
+
+static void wpng_cleanup(void)
+{
+    if (wpng_info.outfile) {
+        fclose(wpng_info.outfile);
+        wpng_info.outfile = NULL;
+    }
+
+    if (wpng_info.infile) {
+        fclose(wpng_info.infile);
+        wpng_info.infile = NULL;
+    }
+
+    if (wpng_info.image_data) {
+        free(wpng_info.image_data);
+        wpng_info.image_data = NULL;
+    }
+
+    if (wpng_info.row_pointers) {
+        free(wpng_info.row_pointers);
+        wpng_info.row_pointers = NULL;
+    }
+}
+
+
+
+
+#ifdef DOS_OS2_W32
+
+static char *dos_kbd_gets(char *buf, int len)
+{
+    int ch, count=0;
+
+    do {
+        buf[count++] = ch = getche();
+    } while (ch != '\r' && count < len-1);
+
+    buf[count--] = '\0';        /* terminate string */
+    if (buf[count] == '\r')     /* Enter key makes CR, so change to newline */
+        buf[count] = '\n';
+
+    fprintf(stderr, "\n");      /* Enter key does *not* cause a newline */
+    fflush(stderr);
+
+    return buf;
+}
+
+#endif /* DOS_OS2_W32 */
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/writepng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/writepng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/writepng.c	(revision 107811)
@@ -0,0 +1,401 @@
+/*---------------------------------------------------------------------------
+
+   wpng - simple PNG-writing program                             writepng.c
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007, 2017 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+
+#include <stdlib.h>     /* for exit() prototype */
+#include <zlib.h>
+
+#include "png.h"        /* libpng header, includes setjmp.h */
+#include "writepng.h"   /* typedefs, common macros, public prototypes */
+
+
+/* local prototype */
+
+static void writepng_error_handler(png_structp png_ptr, png_const_charp msg);
+
+
+
+void writepng_version_info(void)
+{
+  fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
+    PNG_LIBPNG_VER_STRING, png_libpng_ver);
+  fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
+    ZLIB_VERSION, zlib_version);
+}
+
+
+
+
+/* returns 0 for success, 2 for libpng problem, 4 for out of memory, 11 for
+ *  unexpected pnmtype; note that outfile might be stdout */
+
+int writepng_init(mainprog_info *mainprog_ptr)
+{
+    png_structp  png_ptr;       /* note:  temporary variables! */
+    png_infop  info_ptr;
+    int color_type, interlace_type;
+
+
+    /* could also replace libpng warning-handler (final NULL), but no need: */
+
+    png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), mainprog_ptr,
+      writepng_error_handler, NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_write_struct(&png_ptr, NULL);
+        return 4;   /* out of memory */
+    }
+
+
+    /* setjmp() must be called in every function that calls a PNG-writing
+     * libpng function, unless an alternate error handler was installed--
+     * but compatible error handlers must either use longjmp() themselves
+     * (as in this program) or some other method to return control to
+     * application code, so here we go: */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return 2;
+    }
+
+
+    /* make sure outfile is (re)opened in BINARY mode */
+
+    png_init_io(png_ptr, mainprog_ptr->outfile);
+
+
+    /* set the compression levels--in general, always want to leave filtering
+     * turned on (except for palette images) and allow all of the filters,
+     * which is the default; want 32K zlib window, unless entire image buffer
+     * is 16K or smaller (unknown here)--also the default; usually want max
+     * compression (NOT the default); and remaining compression flags should
+     * be left alone */
+
+    png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
+/*
+    >> this is default for no filtering; Z_FILTERED is default otherwise:
+    png_set_compression_strategy(png_ptr, Z_DEFAULT_STRATEGY);
+    >> these are all defaults:
+    png_set_compression_mem_level(png_ptr, 8);
+    png_set_compression_window_bits(png_ptr, 15);
+    png_set_compression_method(png_ptr, 8);
+ */
+
+
+    /* set the image parameters appropriately */
+
+    if (mainprog_ptr->pnmtype == 5)
+        color_type = PNG_COLOR_TYPE_GRAY;
+    else if (mainprog_ptr->pnmtype == 6)
+        color_type = PNG_COLOR_TYPE_RGB;
+    else if (mainprog_ptr->pnmtype == 8)
+        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+    else {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return 11;
+    }
+
+    interlace_type = mainprog_ptr->interlaced? PNG_INTERLACE_ADAM7 :
+                                               PNG_INTERLACE_NONE;
+
+    png_set_IHDR(png_ptr, info_ptr, mainprog_ptr->width, mainprog_ptr->height,
+      mainprog_ptr->sample_depth, color_type, interlace_type,
+      PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+    if (mainprog_ptr->gamma > 0.0)
+        png_set_gAMA(png_ptr, info_ptr, mainprog_ptr->gamma);
+
+    if (mainprog_ptr->have_bg) {   /* we know it's RGBA, not gray+alpha */
+        png_color_16  background;
+
+        background.red = mainprog_ptr->bg_red;
+        background.green = mainprog_ptr->bg_green;
+        background.blue = mainprog_ptr->bg_blue;
+        png_set_bKGD(png_ptr, info_ptr, &background);
+    }
+
+    if (mainprog_ptr->have_time) {
+        png_time  modtime;
+
+        png_convert_from_time_t(&modtime, mainprog_ptr->modtime);
+        png_set_tIME(png_ptr, info_ptr, &modtime);
+    }
+
+    if (mainprog_ptr->have_text) {
+        png_text  text[6];
+        int  num_text = 0;
+
+        if (mainprog_ptr->have_text & TEXT_TITLE) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Title";
+            text[num_text].text = mainprog_ptr->title;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_AUTHOR) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Author";
+            text[num_text].text = mainprog_ptr->author;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_DESC) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Description";
+            text[num_text].text = mainprog_ptr->desc;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_COPY) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Copyright";
+            text[num_text].text = mainprog_ptr->copyright;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_EMAIL) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "E-mail";
+            text[num_text].text = mainprog_ptr->email;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_URL) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "URL";
+            text[num_text].text = mainprog_ptr->url;
+            ++num_text;
+        }
+        png_set_text(png_ptr, info_ptr, text, num_text);
+    }
+
+
+    /* write all chunks up to (but not including) first IDAT */
+
+    png_write_info(png_ptr, info_ptr);
+
+
+    /* if we wanted to write any more text info *after* the image data, we
+     * would set up text struct(s) here and call png_set_text() again, with
+     * just the new data; png_set_tIME() could also go here, but it would
+     * have no effect since we already called it above (only one tIME chunk
+     * allowed) */
+
+
+    /* set up the transformations:  for now, just pack low-bit-depth pixels
+     * into bytes (one, two or four pixels per byte) */
+
+    png_set_packing(png_ptr);
+/*  png_set_shift(png_ptr, &sig_bit);  to scale low-bit-depth values */
+
+
+    /* make sure we save our pointers for use in writepng_encode_image() */
+
+    mainprog_ptr->png_ptr = png_ptr;
+    mainprog_ptr->info_ptr = info_ptr;
+
+
+    /* OK, that's all we need to do for now; return happy */
+
+    return 0;
+}
+
+
+
+
+
+/* returns 0 for success, 2 for libpng (longjmp) problem */
+
+int writepng_encode_image(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* and now we just write the whole image; libpng takes care of interlacing
+     * for us */
+
+    png_write_image(png_ptr, mainprog_ptr->row_pointers);
+
+
+    /* since that's it, we also close out the end of the PNG file now--if we
+     * had any text or time info to write after the IDATs, second argument
+     * would be info_ptr, but we optimize slightly by sending NULL pointer: */
+
+    png_write_end(png_ptr, NULL);
+
+    return 0;
+}
+
+
+
+
+
+/* returns 0 if succeeds, 2 if libpng problem */
+
+int writepng_encode_row(mainprog_info *mainprog_ptr)  /* NON-interlaced only! */
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* image_data points at our one row of image data */
+
+    png_write_row(png_ptr, mainprog_ptr->image_data);
+
+    return 0;
+}
+
+
+
+
+
+/* returns 0 if succeeds, 2 if libpng problem */
+
+int writepng_encode_finish(mainprog_info *mainprog_ptr)   /* NON-interlaced! */
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+
+
+    /* close out PNG file; if we had any text or time info to write after
+     * the IDATs, second argument would be info_ptr: */
+
+    png_write_end(png_ptr, NULL);
+
+    return 0;
+}
+
+
+
+
+
+void writepng_cleanup(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+
+    if (png_ptr && info_ptr)
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+}
+
+
+
+
+
+static void writepng_error_handler(png_structp png_ptr, png_const_charp msg)
+{
+    mainprog_info  *mainprog_ptr;
+
+    /* This function, aside from the extra step of retrieving the "error
+     * pointer" (below) and the fact that it exists within the application
+     * rather than within libpng, is essentially identical to libpng's
+     * default error handler.  The second point is critical:  since both
+     * setjmp() and longjmp() are called from the same code, they are
+     * guaranteed to have compatible notions of how big a jmp_buf is,
+     * regardless of whether _BSD_SOURCE or anything else has (or has not)
+     * been defined. */
+
+    fprintf(stderr, "writepng libpng error: %s\n", msg);
+    fflush(stderr);
+
+    mainprog_ptr = png_get_error_ptr(png_ptr);
+    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
+        fprintf(stderr,
+          "writepng severe error:  jmpbuf not recoverable; terminating.\n");
+        fflush(stderr);
+        exit(99);
+    }
+
+    /* Now we have our data structure we can use the information in it
+     * to return control to our own higher level code (all the points
+     * where 'setjmp' is called in this file.)  This will work with other
+     * error handling mechanisms as well - libpng always calls png_error
+     * when it can proceed no further, thus, so long as the error handler
+     * is intercepted, application code can do its own error recovery.
+     */
+    longjmp(mainprog_ptr->jmpbuf, 1);
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/gregbook/writepng.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/gregbook/writepng.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/gregbook/writepng.h	(revision 107811)
@@ -0,0 +1,133 @@
+/*---------------------------------------------------------------------------
+
+   wpng - simple PNG-writing program                             writepng.h
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+
+
+      LICENSE 1 ("BSD-like with advertising clause"):
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+
+      LICENSE 2 (GNU GPL v2 or later):
+
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+  ---------------------------------------------------------------------------*/
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+
+#define TEXT_TITLE    0x01
+#define TEXT_AUTHOR   0x02
+#define TEXT_DESC     0x04
+#define TEXT_COPY     0x08
+#define TEXT_EMAIL    0x10
+#define TEXT_URL      0x20
+
+#define TEXT_TITLE_OFFSET        0
+#define TEXT_AUTHOR_OFFSET      72
+#define TEXT_COPY_OFFSET     (2*72)
+#define TEXT_EMAIL_OFFSET    (3*72)
+#define TEXT_URL_OFFSET      (4*72)
+#define TEXT_DESC_OFFSET     (5*72)
+
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+
+typedef struct _mainprog_info {
+    double gamma;
+    long width;
+    long height;
+    time_t modtime;
+    FILE *infile;
+    FILE *outfile;
+    void *png_ptr;
+    void *info_ptr;
+    uch *image_data;
+    uch **row_pointers;
+    char *title;
+    char *author;
+    char *desc;
+    char *copyright;
+    char *email;
+    char *url;
+    int filter;    /* command-line-filter flag, not PNG row filter! */
+    int pnmtype;
+    int sample_depth;
+    int interlaced;
+    int have_bg;
+    int have_time;
+    int have_text;
+    jmp_buf jmpbuf;
+    uch bg_red;
+    uch bg_green;
+    uch bg_blue;
+} mainprog_info;
+
+
+/* prototypes for public functions in writepng.c */
+
+void writepng_version_info(void);
+
+int writepng_init(mainprog_info *mainprog_ptr);
+
+int writepng_encode_image(mainprog_info *mainprog_ptr);
+
+int writepng_encode_row(mainprog_info *mainprog_ptr);
+
+int writepng_encode_finish(mainprog_info *mainprog_ptr);
+
+void writepng_cleanup(mainprog_info *mainprog_ptr);
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/fakepng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/fakepng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/fakepng.c	(revision 107811)
@@ -0,0 +1,65 @@
+/* Fake a PNG - just write it out directly.
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2014.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ */
+
+#include <stdio.h>
+#include <zlib.h> /* for crc32 */
+
+void
+put_uLong(uLong val)
+{
+   putchar(val >> 24);
+   putchar(val >> 16);
+   putchar(val >>  8);
+   putchar(val >>  0);
+}
+
+void
+put_chunk(const unsigned char *chunk, uInt length)
+{
+   uLong crc;
+
+   put_uLong(length-4); /* Exclude the tag */
+
+   fwrite(chunk, length, 1, stdout);
+
+   crc = crc32(0, Z_NULL, 0);
+   put_uLong(crc32(crc, chunk, length));
+}
+
+const unsigned char signature[] =
+{
+   137, 80, 78, 71, 13, 10, 26, 10
+};
+
+const unsigned char IHDR[] =
+{
+   73, 72, 68, 82, /* IHDR */
+   0, 0, 0, 1, /* width */
+   0, 0, 0, 1, /* height */
+   1, /* bit depth */
+   0, /* color type: greyscale */
+   0, /* compression method */
+   0, /* filter method */
+   0  /* interlace method: none */
+};
+
+const unsigned char unknown[] =
+{
+   'u', 'n', 'K', 'n' /* "unKn" - private safe to copy */
+};
+
+int
+main(void)
+{
+   fwrite(signature, sizeof signature, 1, stdout);
+   put_chunk(IHDR, sizeof IHDR);
+
+   for (;;)
+      put_chunk(unknown, sizeof unknown);
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/gentests.sh
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/gentests.sh	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/gentests.sh	(revision 107811)
@@ -0,0 +1,100 @@
+#!/bin/sh
+#
+# Copyright (c) 2013 John Cunningham Bowler
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Generate a set of PNG test images.  The images are generated in a
+# sub-directory called 'tests' by default, however a command line argument will
+# change that name.  The generation requires a built version of makepng in the
+# current directory.
+#
+usage(){
+   exec >&2
+   echo "$0 [<directory>]"
+   echo '  Generate a set of PNG test files in "directory" ("tests" by default)'
+   exit 1
+}
+
+mp="$PWD/makepng"
+test -x "$mp" || {
+   exec >&2
+   echo "$0: the 'makepng' program must exist"
+   echo "  in the directory within which this program:"
+   echo "    $mp"
+   echo "  is executed"
+   usage
+}
+
+# Just one argument: the directory
+testdir="tests"
+test $# -gt 1 && {
+   testdir="$1"
+   shift
+}
+test $# -eq 0 || usage
+
+# Take care not to clobber something
+if test -e "$testdir"
+then
+   test -d "$testdir" || usage
+else
+   # mkdir -p isn't portable, so do the following
+   mkdir "$testdir" 2>/dev/null || mkdir -p "$testdir" || usage
+fi
+
+# This fails in a very satisfactory way if it's not accessible
+cd "$testdir"
+:>"test$$.png" || {
+   exec >&2
+   echo "$testdir: directory not writable"
+   usage
+}
+rm "test$$.png" || {
+   exec >&2
+   echo "$testdir: you have create but not write privileges here."
+   echo "  This is unexpected.  You have a spurion; "'"'"test$$.png"'"'"."
+   echo "  You need to remove this yourself.  Try a different directory."
+   exit 1
+}
+
+# Now call makepng ($mp) to create every file we can think of with a
+# reasonable name
+doit(){
+   for gamma in "" --sRGB --linear --1.8
+   do
+      case "$gamma" in
+         "")
+            gname=;;
+         --sRGB)
+            gname="-srgb";;
+         --linear)
+            gname="-lin";;
+         --1.8)
+            gname="-18";;
+         *)
+            gname="-$gamma";;
+      esac
+      "$mp" $gamma "$1" "$2" "test-$1-$2$gname.png"
+   done
+}
+#
+for ct in gray palette
+do
+   for bd in 1 2 4 8
+   do
+      doit "$ct" "$bd"
+   done
+done
+#
+doit "gray" "16"
+#
+for ct in gray-alpha rgb rgb-alpha
+do
+   for bd in 8 16
+   do
+      doit "$ct" "$bd"
+   done
+done
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/makepng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/makepng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/makepng.c	(revision 107811)
@@ -0,0 +1,1948 @@
+/* makepng.c */
+#define _ISOC99_SOURCE
+/* Copyright: */
+#define COPYRIGHT "\251 2013,2015 John Cunningham Bowler"
+/*
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Make a test PNG image.  The arguments are as follows:
+ *
+ *    makepng [--sRGB|--linear|--1.8] [--tRNS] [--nofilters] \
+ *       color-type bit-depth [file-name]
+ *
+ * The color-type may be numeric (and must match the numbers used by the PNG
+ * specification) or one of the format names listed below.  The bit-depth is the
+ * component bit depth, or the pixel bit-depth for a color-mapped image.
+ *
+ * Without any options no color-space information is written, with the options
+ * an sRGB or the appropriate gAMA chunk is written.  "1.8" refers to the
+ * display system used on older Apple computers to correct for high ambient
+ * light levels in the viewing environment; it applies a transform of
+ * approximately value^(1/1.45) to the color values and so a gAMA chunk of 65909
+ * is written (1.45/2.2).
+ *
+ * The image data is generated internally.  Unless --color is given the images
+ * used are as follows:
+ *
+ * 1 channel: a square image with a diamond, the least luminous colors are on
+ *    the edge of the image, the most luminous in the center.
+ *
+ * 2 channels: the color channel increases in luminosity from top to bottom, the
+ *    alpha channel increases in opacity from left to right.
+ *
+ * 3 channels: linear combinations of, from the top-left corner clockwise,
+ *    black, green, white, red.
+ *
+ * 4 channels: linear combinations of, from the top-left corner clockwise,
+ *    transparent, red, green, blue.
+ *
+ * For color-mapped images a four channel color-map is used and if --tRNS is
+ * given the PNG file has a tRNS chunk, as follows:
+ *
+ * 1-bit: entry 0 is transparent-red, entry 1 is opaque-white
+ * 2-bit: entry 0: transparent-green
+ *        entry 1: 40%-red
+ *        entry 2: 80%-blue
+ *        entry 3: opaque-white
+ * 4-bit: the 16 combinations of the 2-bit case
+ * 8-bit: the 256 combinations of the 4-bit case
+ *
+ * The palette always has 2^bit-depth entries and the tRNS chunk one fewer.  The
+ * image is the 1-channel diamond, but using palette index, not luminosity.
+ *
+ * For formats other than color-mapped ones if --tRNS is specified a tRNS chunk
+ * is generated with all channels equal to the low bits of 0x0101.
+ *
+ * Image size is determined by the final pixel depth in bits, i.e. channels x
+ * bit-depth, as follows:
+ *
+ * 8 bits or less:    64x64
+ * 16 bits:           256x256
+ * More than 16 bits: 1024x1024
+ *
+ * Row filtering is the libpng default but may be turned off (the 'none' filter
+ * is used on every row) with the --nofilters option.
+ *
+ * The images are not interlaced.
+ *
+ * If file-name is given then the PNG is written to that file, else it is
+ * written to stdout.  Notice that stdout is not supported on systems where, by
+ * default, it assumes text output; this program makes no attempt to change the
+ * text mode of stdout!
+ *
+ *    makepng --color=<color> ...
+ *
+ * If --color is given then the whole image has that color, color-mapped images
+ * will have exactly one palette entry and all image files with be 16x16 in
+ * size.  The color value is 1 to 4 decimal numbers as appropriate for the color
+ * type.
+ *
+ *    makepng --small ...
+ *
+ * If --small is given the images are no larger than required to include every
+ * possible pixel value for the format.
+ *
+ * For formats with pixels 8 bits or fewer in size the images consist of a
+ * single row with 2^pixel-depth pixels, one of every possible value.
+ *
+ * For formats with 16-bit pixels a 256x256 image is generated containing every
+ * possible pixel value.
+ *
+ * For larger pixel sizes a 256x256 image is generated where the first row
+ * consists of each pixel that has identical byte values throughout the pixel
+ * followed by rows where the byte values differ within the pixel.
+ *
+ * In all cases the pixel values are arranged in such a way that the SUB and UP
+ * filters give byte sequences for maximal zlib compression.  By default (if
+ * --nofilters is not given) the SUB filter is used on the first row and the UP
+ * filter on all following rows.
+ *
+ * The --small option is meant to provide good test-case coverage, however the
+ * images are not easy to examine visually.  Without the --small option the
+ * images contain identical color values; the pixel values are adjusted
+ * according to the gamma encoding with no gamma encoding being interpreted as
+ * sRGB.
+ *
+ * LICENSING
+ * =========
+ *
+ * This code is copyright of the authors, see the COPYRIGHT define above.  The
+ * code is licensed as above, using the libpng license.  The code generates
+ * images which are solely the product of the code; the options choose which of
+ * the many possibilities to generate.  The images that result (but not the code
+ * which generates them) are licensed as defined here:
+ *
+ * IMPORTANT: the COPYRIGHT #define must contain ISO-Latin-1 characters, the
+ * IMAGE_LICENSING #define must contain UTF-8 characters.  The 'copyright'
+ * symbol 0xA9U (\251) in ISO-Latin-1 encoding and 0xC20xA9 (\302\251) in UTF-8.
+ */
+#define IMAGE_LICENSING "Dedicated to the public domain per Creative Commons "\
+    "license \"CC0 1.0\"; https://creativecommons.org/publicdomain/zero/1.0/"
+
+#include <stddef.h> /* for offsetof */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <math.h>
+#include <errno.h>
+#include <assert.h>
+#include <stdint.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#include <zlib.h>
+
+/* Work round for GCC complaints about casting a (double) function result to
+ * an unsigned:
+ */
+static unsigned int
+flooru(double d)
+{
+   d = floor(d);
+   return (unsigned int)d;
+}
+
+static png_byte
+floorb(double d)
+{
+   d = floor(d);
+   return (png_byte)d;
+}
+
+/* This structure is used for inserting extra chunks (the --insert argument, not
+ * documented above.)
+ */
+typedef struct chunk_insert
+{
+   struct chunk_insert *next;
+   void               (*insert)(png_structp, png_infop, int, png_charpp);
+   int                  nparams;
+   png_charp            parameters[1];
+} chunk_insert;
+
+static unsigned int
+channels_of_type(int color_type)
+{
+   if (color_type & PNG_COLOR_MASK_PALETTE)
+      return 1;
+
+   else
+   {
+      int channels = 1;
+
+      if (color_type & PNG_COLOR_MASK_COLOR)
+         channels = 3;
+
+      if (color_type & PNG_COLOR_MASK_ALPHA)
+         return channels + 1;
+
+      else
+         return channels;
+   }
+}
+
+static unsigned int
+pixel_depth_of_type(int color_type, int bit_depth)
+{
+   return channels_of_type(color_type) * bit_depth;
+}
+
+static unsigned int
+image_size_of_type(int color_type, int bit_depth, unsigned int *colors,
+   int small)
+{
+   if (*colors)
+      return 16;
+
+   else
+   {
+      int pixel_depth = pixel_depth_of_type(color_type, bit_depth);
+
+      if (small)
+      {
+         if (pixel_depth <= 8) /* there will be one row */
+            return 1 << pixel_depth;
+
+         else
+            return 256;
+      }
+
+      else if (pixel_depth < 8)
+         return 64;
+
+      else if (pixel_depth > 16)
+         return 1024;
+
+      else
+         return 256;
+   }
+}
+
+static void
+set_color(png_colorp color, png_bytep trans, unsigned int red,
+   unsigned int green, unsigned int blue, unsigned int alpha,
+   png_const_bytep gamma_table)
+{
+   color->red = gamma_table[red];
+   color->green = gamma_table[green];
+   color->blue = gamma_table[blue];
+   *trans = (png_byte)alpha;
+}
+
+static int
+generate_palette(png_colorp palette, png_bytep trans, int bit_depth,
+   png_const_bytep gamma_table, unsigned int *colors)
+{
+   /*
+    * 1-bit: entry 0 is transparent-red, entry 1 is opaque-white
+    * 2-bit: entry 0: transparent-green
+    *        entry 1: 40%-red
+    *        entry 2: 80%-blue
+    *        entry 3: opaque-white
+    * 4-bit: the 16 combinations of the 2-bit case
+    * 8-bit: the 256 combinations of the 4-bit case
+    */
+   switch (colors[0])
+   {
+      default:
+         fprintf(stderr, "makepng: --colors=...: invalid count %u\n",
+            colors[0]);
+         exit(1);
+
+      case 1:
+         set_color(palette+0, trans+0, colors[1], colors[1], colors[1], 255,
+            gamma_table);
+         return 1;
+
+      case 2:
+         set_color(palette+0, trans+0, colors[1], colors[1], colors[1],
+            colors[2], gamma_table);
+         return 1;
+
+      case 3:
+         set_color(palette+0, trans+0, colors[1], colors[2], colors[3], 255,
+            gamma_table);
+         return 1;
+
+      case 4:
+         set_color(palette+0, trans+0, colors[1], colors[2], colors[3],
+            colors[4], gamma_table);
+         return 1;
+
+      case 0:
+         if (bit_depth == 1)
+         {
+            set_color(palette+0, trans+0, 255, 0, 0, 0, gamma_table);
+            set_color(palette+1, trans+1, 255, 255, 255, 255, gamma_table);
+            return 2;
+         }
+
+         else
+         {
+            unsigned int size = 1U << (bit_depth/2); /* 2, 4 or 16 */
+            unsigned int x, y;
+            volatile unsigned int ip = 0;
+
+            for (x=0; x<size; ++x)
+            {
+               for (y=0; y<size; ++y)
+               {
+                  ip = x + (size * y);
+
+                  /* size is at most 16, so the scaled value below fits in 16 bits
+                  */
+#                 define interp(pos, c1, c2) ((pos * c1) + ((size-pos) * c2))
+#                 define xyinterp(x, y, c1, c2, c3, c4) (((size * size / 2) +\
+                     (interp(x, c1, c2) * y + (size-y) * interp(x, c3, c4))) /\
+                     (size*size))
+
+                  set_color(palette+ip, trans+ip,
+                     /* color:    green, red,blue,white */
+                     xyinterp(x, y,   0, 255,   0, 255),
+                     xyinterp(x, y, 255,   0,   0, 255),
+                     xyinterp(x, y,   0,   0, 255, 255),
+                     /* alpha:        0, 102, 204, 255) */
+                     xyinterp(x, y,   0, 102, 204, 255),
+                     gamma_table);
+               }
+            }
+
+            return ip+1;
+         }
+   }
+}
+
+static void
+set_value(png_bytep row, size_t rowbytes, png_uint_32 x, unsigned int bit_depth,
+   png_uint_32 value, png_const_bytep gamma_table, double conv)
+{
+   unsigned int mask = (1U << bit_depth)-1;
+
+   x *= bit_depth;  /* Maximum x is 4*1024, maximum bit_depth is 16 */
+
+   if (value <= mask)
+   {
+      png_uint_32 offset = x >> 3;
+
+      if (offset < rowbytes && (bit_depth < 16 || offset+1 < rowbytes))
+      {
+         row += offset;
+
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+               /* Don't gamma correct - values get smashed */
+               {
+                  unsigned int shift = (8 - bit_depth) - (x & 0x7U);
+
+                  mask <<= shift;
+                  value = (value << shift) & mask;
+                  *row = (png_byte)((*row & ~mask) | value);
+               }
+               return;
+
+            default:
+               fprintf(stderr, "makepng: bad bit depth (internal error)\n");
+               exit(1);
+
+            case 16:
+               value = flooru(65535*pow(value/65535.,conv)+.5);
+               *row++ = (png_byte)(value >> 8);
+               *row = (png_byte)value;
+               return;
+
+            case 8:
+               *row = gamma_table[value];
+               return;
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "makepng: row buffer overflow (internal error)\n");
+         exit(1);
+      }
+   }
+
+   else
+   {
+      fprintf(stderr, "makepng: component overflow (internal error)\n");
+      exit(1);
+   }
+}
+
+static int /* filter mask for row */
+generate_row(png_bytep row, size_t rowbytes, unsigned int y, int color_type,
+   int bit_depth, png_const_bytep gamma_table, double conv,
+   unsigned int *colors, int small)
+{
+   int filters = 0; /* file *MASK*, 0 means the default, not NONE */
+   png_uint_32 size_max =
+      image_size_of_type(color_type, bit_depth, colors, small)-1;
+   png_uint_32 depth_max = (1U << bit_depth)-1; /* up to 65536 */
+
+   if (colors[0] == 0 && small)
+   {
+      unsigned int pixel_depth = pixel_depth_of_type(color_type, bit_depth);
+
+      /* For pixel depths less than 16 generate a single row containing all the
+       * possible pixel values.  For 16 generate all 65536 byte pair
+       * combinations in a 256x256 pixel array.
+       */
+      switch (pixel_depth)
+      {
+         case 1:
+            assert(y == 0 && rowbytes == 1 && size_max == 1);
+            row[0] = 0x6CU; /* binary: 01101100, only top 2 bits used */
+            filters = PNG_FILTER_NONE;
+            break;
+
+         case 2:
+            assert(y == 0 && rowbytes == 1 && size_max == 3);
+            row[0] = 0x1BU; /* binary 00011011, all bits used */
+            filters = PNG_FILTER_NONE;
+            break;
+
+         case 4:
+            assert(y == 0 && rowbytes == 8 && size_max == 15);
+            row[0] = 0x01U;
+            row[1] = 0x23U; /* SUB gives 0x22U for all following bytes */
+            row[2] = 0x45U;
+            row[3] = 0x67U;
+            row[4] = 0x89U;
+            row[5] = 0xABU;
+            row[6] = 0xCDU;
+            row[7] = 0xEFU;
+            filters = PNG_FILTER_SUB;
+            break;
+
+         case 8:
+            /* The row will have all the pixel values in order starting with
+             * '1', the SUB filter will change every byte into '1' (including
+             * the last, which generates pixel value '0').  Since the SUB filter
+             * has value 1 this should result in maximum compression.
+             */
+            assert(y == 0 && rowbytes == 256 && size_max == 255);
+            for (;;)
+            {
+               row[size_max] = 0xFFU & (size_max+1);
+               if (size_max == 0)
+                  break;
+               --size_max;
+            }
+            filters = PNG_FILTER_SUB;
+            break;
+
+         case 16:
+            /* Rows are generated such that each row has a constant difference
+             * between the first and second byte of each pixel and so that the
+             * difference increases by 1 at each row.  The rows start with the
+             * first byte value of 0 and the value increases to 255 across the
+             * row.
+             *
+             * The difference starts at 1, so the first row is:
+             *
+             *     0 1 1 2 2 3 3 4 ... 254 255 255 0
+             *
+             * This means that running the SUB filter on the first row produces:
+             *
+             *   [SUB==1] 0 1 0 1 0 1...
+             *
+             * Then the difference is 2 on the next row, giving:
+             *
+             *    0 2 1 3 2 4 3 5 ... 254 0 255 1
+             *
+             * When the UP filter is run on this libpng produces:
+             *
+             *   [UP ==2] 0 1 0 1 0 1...
+             *
+             * And so on for all the remain rows to the final two * rows:
+             *
+             *    row 254: 0 255 1 0 2 1 3 2 4 3 ... 254 253 255 254
+             *    row 255: 0   0 1 1 2 2 3 3 4 4 ... 254 254 255 255
+             */
+            assert(rowbytes == 512 && size_max == 255);
+            for (;;)
+            {
+               row[2*size_max  ] = 0xFFU & size_max;
+               row[2*size_max+1] = 0xFFU & (size_max+y+1);
+               if (size_max == 0)
+                  break;
+               --size_max;
+            }
+            /* The first row must include PNG_FILTER_UP so that libpng knows we
+             * need to keep it for the following row:
+             */
+            filters = (y == 0 ? PNG_FILTER_SUB+PNG_FILTER_UP : PNG_FILTER_UP);
+            break;
+
+         case 24:
+         case 32:
+         case 48:
+         case 64:
+            /* The rows are filled by an algorithm similar to the above, in the
+             * first row pixel bytes are all equal, increasing from 0 by 1 for
+             * each pixel.  In the second row the bytes within a pixel are
+             * incremented 1,3,5,7,... from the previous row byte.  Using an odd
+             * number ensures all the possible byte values are used.
+             */
+            assert(size_max == 255 && rowbytes == 256*(pixel_depth>>3));
+            pixel_depth >>= 3; /* now in bytes */
+            while (rowbytes > 0)
+            {
+               const size_t pixel_index = --rowbytes/pixel_depth;
+
+               if (y == 0)
+                  row[rowbytes] = 0xFFU & pixel_index;
+
+               else
+               {
+                  const size_t byte_offset =
+                     rowbytes - pixel_index * pixel_depth;
+
+                  row[rowbytes] =
+                     0xFFU & (pixel_index + (byte_offset * 2*y) + 1);
+               }
+            }
+            filters = (y == 0 ? PNG_FILTER_SUB+PNG_FILTER_UP : PNG_FILTER_UP);
+            break;
+
+         default:
+            assert(0/*NOT REACHED*/);
+      }
+   }
+
+   else switch (channels_of_type(color_type))
+   {
+   /* 1 channel: a square image with a diamond, the least luminous colors are on
+    *    the edge of the image, the most luminous in the center.
+    */
+      case 1:
+         {
+            png_uint_32 x;
+            png_uint_32 base = 2*size_max - abs(2*y-size_max);
+
+            for (x=0; x<=size_max; ++x)
+            {
+               png_uint_32 luma = base - abs(2*x-size_max);
+
+               /* 'luma' is now in the range 0..2*size_max, we need
+                * 0..depth_max
+                */
+               luma = (luma*depth_max + size_max) / (2*size_max);
+               set_value(row, rowbytes, x, bit_depth, luma, gamma_table, conv);
+            }
+         }
+         break;
+
+   /* 2 channels: the color channel increases in luminosity from top to bottom,
+    *    the alpha channel increases in opacity from left to right.
+    */
+      case 2:
+         {
+            png_uint_32 alpha = (depth_max * y * 2 + size_max) / (2 * size_max);
+            png_uint_32 x;
+
+            for (x=0; x<=size_max; ++x)
+            {
+               set_value(row, rowbytes, 2*x, bit_depth,
+                  (depth_max * x * 2 + size_max) / (2 * size_max), gamma_table,
+                  conv);
+               set_value(row, rowbytes, 2*x+1, bit_depth, alpha, gamma_table,
+                  conv);
+            }
+         }
+         break;
+
+   /* 3 channels: linear combinations of, from the top-left corner clockwise,
+    *    black, green, white, red.
+    */
+      case 3:
+         {
+            /* x0: the black->red scale (the value of the red component) at the
+             *     start of the row (blue and green are 0).
+             * x1: the green->white scale (the value of the red and blue
+             *     components at the end of the row; green is depth_max).
+             */
+            png_uint_32 Y = (depth_max * y * 2 + size_max) / (2 * size_max);
+            png_uint_32 x;
+
+            /* Interpolate x/depth_max from start to end:
+             *
+             *        start end         difference
+             * red:     Y    Y            0
+             * green:   0   depth_max   depth_max
+             * blue:    0    Y            Y
+             */
+            for (x=0; x<=size_max; ++x)
+            {
+               set_value(row, rowbytes, 3*x+0, bit_depth, /* red */ Y,
+                     gamma_table, conv);
+               set_value(row, rowbytes, 3*x+1, bit_depth, /* green */
+                  (depth_max * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+               set_value(row, rowbytes, 3*x+2, bit_depth, /* blue */
+                  (Y * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+            }
+         }
+         break;
+
+   /* 4 channels: linear combinations of, from the top-left corner clockwise,
+    *    transparent, red, green, blue.
+    */
+      case 4:
+         {
+            /* x0: the transparent->blue scale (the value of the blue and alpha
+             *     components) at the start of the row (red and green are 0).
+             * x1: the red->green scale (the value of the red and green
+             *     components at the end of the row; blue is 0 and alpha is
+             *     depth_max).
+             */
+            png_uint_32 Y = (depth_max * y * 2 + size_max) / (2 * size_max);
+            png_uint_32 x;
+
+            /* Interpolate x/depth_max from start to end:
+             *
+             *        start    end       difference
+             * red:     0   depth_max-Y depth_max-Y
+             * green:   0       Y             Y
+             * blue:    Y       0            -Y
+             * alpha:   Y    depth_max  depth_max-Y
+             */
+            for (x=0; x<=size_max; ++x)
+            {
+               set_value(row, rowbytes, 4*x+0, bit_depth, /* red */
+                  ((depth_max-Y) * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+               set_value(row, rowbytes, 4*x+1, bit_depth, /* green */
+                  (Y * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+               set_value(row, rowbytes, 4*x+2, bit_depth, /* blue */
+                  Y - (Y * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+               set_value(row, rowbytes, 4*x+3, bit_depth, /* alpha */
+                  Y + ((depth_max-Y) * x * 2 + size_max) / (2 * size_max),
+                  gamma_table, conv);
+            }
+         }
+         break;
+
+      default:
+         fprintf(stderr, "makepng: internal bad channel count\n");
+         exit(2);
+   }
+
+   else if (color_type & PNG_COLOR_MASK_PALETTE)
+   {
+      /* Palette with fixed color: the image rows are all 0 and the image width
+       * is 16.
+       */
+      memset(row, 0, rowbytes);
+   }
+
+   else if (colors[0] == channels_of_type(color_type))
+      switch (channels_of_type(color_type))
+      {
+         case 1:
+            {
+               png_uint_32 luma = colors[1];
+               png_uint_32 x;
+
+               for (x=0; x<=size_max; ++x)
+                  set_value(row, rowbytes, x, bit_depth, luma, gamma_table,
+                     conv);
+            }
+            break;
+
+         case 2:
+            {
+               png_uint_32 luma = colors[1];
+               png_uint_32 alpha = colors[2];
+               png_uint_32 x;
+
+               for (x=0; x<size_max; ++x)
+               {
+                  set_value(row, rowbytes, 2*x, bit_depth, luma, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 2*x+1, bit_depth, alpha, gamma_table,
+                     conv);
+               }
+            }
+            break;
+
+         case 3:
+            {
+               png_uint_32 red = colors[1];
+               png_uint_32 green = colors[2];
+               png_uint_32 blue = colors[3];
+               png_uint_32 x;
+
+               for (x=0; x<=size_max; ++x)
+               {
+                  set_value(row, rowbytes, 3*x+0, bit_depth, red, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 3*x+1, bit_depth, green, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 3*x+2, bit_depth, blue, gamma_table,
+                     conv);
+               }
+            }
+            break;
+
+         case 4:
+            {
+               png_uint_32 red = colors[1];
+               png_uint_32 green = colors[2];
+               png_uint_32 blue = colors[3];
+               png_uint_32 alpha = colors[4];
+               png_uint_32 x;
+
+               for (x=0; x<=size_max; ++x)
+               {
+                  set_value(row, rowbytes, 4*x+0, bit_depth, red, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 4*x+1, bit_depth, green, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 4*x+2, bit_depth, blue, gamma_table,
+                     conv);
+                  set_value(row, rowbytes, 4*x+3, bit_depth, alpha, gamma_table,
+                     conv);
+               }
+            }
+         break;
+
+         default:
+            fprintf(stderr, "makepng: internal bad channel count\n");
+            exit(2);
+      }
+
+   else
+   {
+      fprintf(stderr,
+         "makepng: --color: count(%u) does not match channels(%u)\n",
+         colors[0], channels_of_type(color_type));
+      exit(1);
+   }
+
+   return filters;
+}
+
+
+static void PNGCBAPI
+makepng_warning(png_structp png_ptr, png_const_charp message)
+{
+   const char **ep = png_get_error_ptr(png_ptr);
+   const char *name;
+
+   if (ep != NULL && *ep != NULL)
+      name = *ep;
+
+   else
+      name = "makepng";
+
+  fprintf(stderr, "%s: warning: %s\n", name, message);
+}
+
+static void PNGCBAPI
+makepng_error(png_structp png_ptr, png_const_charp message)
+{
+   makepng_warning(png_ptr, message);
+   png_longjmp(png_ptr, 1);
+}
+
+static int /* 0 on success, else an error code */
+write_png(const char **name, FILE *fp, int color_type, int bit_depth,
+   volatile png_fixed_point gamma, chunk_insert * volatile insert,
+   unsigned int filters, unsigned int *colors, int small, int tRNS)
+{
+   png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+      name, makepng_error, makepng_warning);
+   volatile png_infop info_ptr = NULL;
+   volatile png_bytep row = NULL;
+
+   if (png_ptr == NULL)
+   {
+      fprintf(stderr, "makepng: OOM allocating write structure\n");
+      return 1;
+   }
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_structp nv_ptr = png_ptr;
+      png_infop nv_info = info_ptr;
+
+      png_ptr = NULL;
+      info_ptr = NULL;
+      png_destroy_write_struct(&nv_ptr, &nv_info);
+      if (row != NULL) free(row);
+      return 1;
+   }
+
+   /* Allow benign errors so that we can write PNGs with errors */
+   png_set_benign_errors(png_ptr, 1/*allowed*/);
+
+   /* Max out the text compression level in an attempt to make the license
+    * small.   If --small then do the same for the IDAT.
+    */
+   if (small)
+      png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
+
+   png_set_text_compression_level(png_ptr, Z_BEST_COMPRESSION);
+
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   {
+      unsigned int size =
+         image_size_of_type(color_type, bit_depth, colors, small);
+      unsigned int ysize;
+      png_fixed_point real_gamma = 45455; /* For sRGB */
+      png_byte gamma_table[256];
+      double conv;
+
+      /* Normally images are square, but with 'small' we want to simply generate
+       * all the pixel values, or all that we reasonably can:
+       */
+      if (small)
+      {
+         unsigned int pixel_depth =
+            pixel_depth_of_type(color_type, bit_depth);
+
+         if (pixel_depth <= 8U)
+         {
+            assert(size == (1U<<pixel_depth));
+            ysize = 1U;
+         }
+
+         else
+         {
+            assert(size == 256U);
+            ysize = 256U;
+         }
+      }
+
+      else
+         ysize = size;
+
+      /* This function uses the libpng values used on read to carry extra
+       * information about the gamma:
+       */
+      if (gamma == PNG_GAMMA_MAC_18)
+         gamma = 65909;
+
+      else if (gamma > 0 && gamma < 1000)
+         gamma = PNG_FP_1;
+
+      if (gamma > 0)
+         real_gamma = gamma;
+
+      {
+         unsigned int i;
+
+         if (real_gamma == 45455)
+         {
+            for (i=0; i<256; ++i)
+            {
+               gamma_table[i] = (png_byte)i;
+               conv = 1.;
+            }
+         }
+
+         else
+         {
+            /* Convert 'i' from sRGB (45455) to real_gamma, this makes
+             * the images look the same regardless of the gAMA chunk.
+             */
+            conv = real_gamma;
+            conv /= 45455;
+
+            gamma_table[0] = 0;
+
+            for (i=1; i<255; ++i)
+               gamma_table[i] = floorb(pow(i/255.,conv) * 255 + .5);
+
+            gamma_table[255] = 255;
+         }
+      }
+
+      png_set_IHDR(png_ptr, info_ptr, size, ysize, bit_depth, color_type,
+         PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+      if (color_type & PNG_COLOR_MASK_PALETTE)
+      {
+         int npalette;
+         png_color palette[256];
+         png_byte trans[256];
+
+         npalette = generate_palette(palette, trans, bit_depth, gamma_table,
+            colors);
+         png_set_PLTE(png_ptr, info_ptr, palette, npalette);
+
+         if (tRNS)
+            png_set_tRNS(png_ptr, info_ptr, trans, npalette-1,
+               NULL/*transparent color*/);
+
+         /* Reset gamma_table to prevent the image rows being changed */
+         for (npalette=0; npalette<256; ++npalette)
+            gamma_table[npalette] = (png_byte)npalette;
+      }
+
+      else if (tRNS)
+      {
+         png_color_16 col;
+
+         col.red = col.green = col.blue = col.gray =
+            0x0101U & ((1U<<bit_depth)-1U);
+         col.index = 0U;
+         png_set_tRNS(png_ptr, info_ptr, NULL/*trans*/, 1U, &col);
+      }
+
+      if (gamma == PNG_DEFAULT_sRGB)
+         png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_ABSOLUTE);
+
+      else if (gamma > 0) /* Else don't set color space information */
+      {
+         png_set_gAMA_fixed(png_ptr, info_ptr, real_gamma);
+
+         /* Just use the sRGB values here. */
+         png_set_cHRM_fixed(png_ptr, info_ptr,
+            /* color      x       y */
+            /* white */ 31270, 32900,
+            /* red   */ 64000, 33000,
+            /* green */ 30000, 60000,
+            /* blue  */ 15000,  6000
+         );
+      }
+
+      /* Insert extra information. */
+      while (insert != NULL)
+      {
+         insert->insert(png_ptr, info_ptr, insert->nparams, insert->parameters);
+         insert = insert->next;
+      }
+
+      /* Write the file header. */
+      png_write_info(png_ptr, info_ptr);
+
+      /* Restrict the filters */
+      png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, filters);
+
+      {
+#        ifdef PNG_WRITE_INTERLACING_SUPPORTED
+            int passes = png_set_interlace_handling(png_ptr);
+#        else /* !WRITE_INTERLACING */
+            int passes = 1;
+#        endif /* !WRITE_INTERLACING */
+         int pass;
+         size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+         row = malloc(rowbytes);
+
+         if (row == NULL)
+            png_error(png_ptr, "OOM allocating row buffer");
+
+         for (pass = 0; pass < passes; ++pass)
+         {
+            unsigned int y;
+
+            for (y=0; y<ysize; ++y)
+            {
+               unsigned int row_filters =
+                  generate_row(row, rowbytes, y, color_type, bit_depth,
+                        gamma_table, conv, colors, small);
+
+               if (row_filters != 0 && filters == PNG_ALL_FILTERS)
+                  png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, row_filters);
+
+               png_write_row(png_ptr, row);
+            }
+         }
+      }
+   }
+
+   /* Finish writing the file. */
+   png_write_end(png_ptr, info_ptr);
+
+   {
+      png_structp nv_ptr = png_ptr;
+      png_infop nv_info = info_ptr;
+
+      png_ptr = NULL;
+      info_ptr = NULL;
+      png_destroy_write_struct(&nv_ptr, &nv_info);
+   }
+   free(row);
+   return 0;
+}
+
+
+static size_t
+load_file(png_const_charp name, png_bytepp result)
+{
+   FILE *fp = tmpfile();
+
+   if (fp != NULL)
+   {
+      FILE *ip = fopen(name, "rb");
+
+      if (ip != NULL)
+      {
+         size_t total = 0;
+         int ch;
+
+         for (;;)
+         {
+            ch = getc(ip);
+            if (ch == EOF) break;
+            putc(ch, fp);
+            ++total;
+         }
+
+         if (ferror(ip))
+         {
+            perror(name);
+            fprintf(stderr, "%s: read error\n", name);
+            (void)fclose(ip);
+         }
+
+         else
+         {
+            (void)fclose(ip);
+
+            if (ferror(fp))
+            {
+               perror("temporary file");
+               fprintf(stderr, "temporary file write error\n");
+            }
+
+            else
+            {
+               rewind(fp);
+
+               if (total > 0)
+               {
+                  /* Round up to a multiple of 4 here to allow an iCCP profile
+                   * to be padded to a 4x boundary.
+                   */
+                  png_bytep data = malloc((total+3)&~3);
+
+                  if (data != NULL)
+                  {
+                     size_t new_size = 0;
+
+                     for (;;)
+                     {
+                        ch = getc(fp);
+                        if (ch == EOF) break;
+                        data[new_size++] = (png_byte)ch;
+                     }
+
+                     if (ferror(fp) || new_size != total)
+                     {
+                        perror("temporary file");
+                        fprintf(stderr, "temporary file read error\n");
+                        free(data);
+                     }
+
+                     else
+                     {
+                        (void)fclose(fp);
+                        *result = data;
+                        return total;
+                     }
+                  }
+
+                  else
+                     fprintf(stderr, "%s: out of memory loading file\n", name);
+               }
+
+               else
+                  fprintf(stderr, "%s: empty file\n", name);
+            }
+         }
+      }
+
+      else
+      {
+         perror(name);
+         fprintf(stderr, "%s: open failed\n", name);
+      }
+
+      fclose(fp);
+   }
+
+   else
+      fprintf(stderr, "makepng: %s: could not open temporary file\n", name);
+
+   exit(1);
+   return 0;
+}
+
+static size_t
+load_fake(png_charp param, png_bytepp profile)
+{
+   char *endptr = NULL;
+   uint64_t size = strtoull(param, &endptr, 0/*base*/);
+
+   /* The 'fake' format is <number>*[string] */
+   if (endptr != NULL && *endptr == '*')
+   {
+      size_t len = strlen(++endptr);
+      size_t result = (size_t)size;
+
+      if (len == 0) len = 1; /* capture the terminating '\0' */
+
+      /* Now repeat that string to fill 'size' bytes. */
+      if (result == size && (*profile = malloc(result)) != NULL)
+      {
+         png_bytep out = *profile;
+
+         if (len == 1)
+            memset(out, *endptr, result);
+
+         else
+         {
+            while (size >= len)
+            {
+               memcpy(out, endptr, len);
+               out += len;
+               size -= len;
+            }
+            memcpy(out, endptr, size);
+         }
+
+         return result;
+      }
+
+      else
+      {
+         fprintf(stderr, "%s: size exceeds system limits\n", param);
+         exit(1);
+      }
+   }
+
+   return 0;
+}
+
+static void
+check_param_count(int nparams, int expect)
+{
+   if (nparams != expect)
+   {
+      fprintf(stderr, "bad parameter count (internal error)\n");
+      exit(1);
+   }
+}
+
+static void
+insert_iCCP(png_structp png_ptr, png_infop info_ptr, int nparams,
+   png_charpp params)
+{
+   png_bytep profile = NULL;
+   png_uint_32 proflen = 0;
+   int result;
+
+   check_param_count(nparams, 2);
+
+   switch (params[1][0])
+   {
+      case '<':
+         {
+            size_t filelen = load_file(params[1]+1, &profile);
+            if (filelen > 0xfffffffc) /* Maximum profile length */
+            {
+               fprintf(stderr, "%s: file too long (%lu) for an ICC profile\n",
+                  params[1]+1, (unsigned long)filelen);
+               exit(1);
+            }
+
+            proflen = (png_uint_32)filelen;
+         }
+         break;
+
+      case '0': case '1': case '2': case '3': case '4':
+      case '5': case '6': case '7': case '8': case '9':
+         {
+            size_t fake_len = load_fake(params[1], &profile);
+
+            if (fake_len > 0) /* else a simple parameter */
+            {
+               if (fake_len > 0xffffffff) /* Maximum profile length */
+               {
+                  fprintf(stderr,
+                     "%s: fake data too long (%lu) for an ICC profile\n",
+                     params[1], (unsigned long)fake_len);
+                  exit(1);
+               }
+               proflen = (png_uint_32)(fake_len & ~3U);
+               /* Always fix up the profile length. */
+               png_save_uint_32(profile, proflen);
+               break;
+            }
+         }
+
+      default:
+         fprintf(stderr, "--insert iCCP \"%s\": unrecognized\n", params[1]);
+         fprintf(stderr, "  use '<' to read a file: \"<filename\"\n");
+         exit(1);
+   }
+
+   result = 1;
+
+   if (proflen & 3)
+   {
+      fprintf(stderr,
+         "makepng: --insert iCCP %s: profile length made a multiple of 4\n",
+         params[1]);
+
+      /* load_file allocates extra space for this padding, the ICC spec requires
+       * padding with zero bytes.
+       */
+      while (proflen & 3)
+         profile[proflen++] = 0;
+   }
+
+   if (profile != NULL && proflen > 3)
+   {
+      png_uint_32 prof_header = png_get_uint_32(profile);
+
+      if (prof_header != proflen)
+      {
+         fprintf(stderr, "--insert iCCP %s: profile length field wrong:\n",
+            params[1]);
+         fprintf(stderr, "  actual %lu, recorded value %lu (corrected)\n",
+            (unsigned long)proflen, (unsigned long)prof_header);
+         png_save_uint_32(profile, proflen);
+      }
+   }
+
+   if (result && profile != NULL && proflen >=4)
+      png_set_iCCP(png_ptr, info_ptr, params[0], PNG_COMPRESSION_TYPE_BASE,
+         profile, proflen);
+
+   if (profile)
+      free(profile);
+
+   if (!result)
+      exit(1);
+}
+
+static void
+clear_text(png_text *text, png_charp keyword)
+{
+   text->compression = -1; /* none */
+   text->key = keyword;
+   text->text = NULL;
+   text->text_length = 0; /* libpng calculates this */
+   text->itxt_length = 0; /* libpng calculates this */
+   text->lang = NULL;
+   text->lang_key = NULL;
+}
+
+static void
+set_text(png_structp png_ptr, png_infop info_ptr, png_textp text,
+   png_charp param)
+{
+   switch (param[0])
+   {
+      case '<':
+         {
+            png_bytep file = NULL;
+
+            text->text_length = load_file(param+1, &file);
+            text->text = (png_charp)file;
+         }
+         break;
+
+      case '0': case '1': case '2': case '3': case '4':
+      case '5': case '6': case '7': case '8': case '9':
+         {
+            png_bytep data = NULL;
+            size_t fake_len = load_fake(param, &data);
+
+            if (fake_len > 0) /* else a simple parameter */
+            {
+               text->text_length = fake_len;
+               text->text = (png_charp)data;
+               break;
+            }
+         }
+
+      default:
+         text->text = param;
+         break;
+   }
+
+   png_set_text(png_ptr, info_ptr, text, 1);
+
+   if (text->text != param)
+      free(text->text);
+}
+
+static void
+insert_tEXt(png_structp png_ptr, png_infop info_ptr, int nparams,
+   png_charpp params)
+{
+   png_text text;
+
+   check_param_count(nparams, 2);
+   clear_text(&text, params[0]);
+   set_text(png_ptr, info_ptr, &text, params[1]);
+}
+
+static void
+insert_zTXt(png_structp png_ptr, png_infop info_ptr, int nparams,
+   png_charpp params)
+{
+   png_text text;
+
+   check_param_count(nparams, 2);
+   clear_text(&text, params[0]);
+   text.compression = 0; /* deflate */
+   set_text(png_ptr, info_ptr, &text, params[1]);
+}
+
+static void
+insert_iTXt(png_structp png_ptr, png_infop info_ptr, int nparams,
+   png_charpp params)
+{
+   png_text text;
+
+   check_param_count(nparams, 4);
+   clear_text(&text, params[0]);
+   text.compression = 2; /* iTXt + deflate */
+   text.lang = params[1];/* language tag */
+   text.lang_key = params[2]; /* translated keyword */
+   set_text(png_ptr, info_ptr, &text, params[3]);
+}
+
+static void
+insert_hIST(png_structp png_ptr, png_infop info_ptr, int nparams,
+      png_charpp params)
+{
+   int i;
+   png_uint_16 freq[256];
+
+   /* libpng takes the count from the PLTE count; we don't check it here but we
+    * do set the array to 0 for unspecified entries.
+    */
+   memset(freq, 0, sizeof freq);
+   for (i=0; i<nparams; ++i)
+   {
+      char *endptr = NULL;
+      unsigned long int l = strtoul(params[i], &endptr, 0/*base*/);
+
+      if (params[i][0] && *endptr == 0 && l <= 65535)
+         freq[i] = (png_uint_16)l;
+
+      else
+      {
+         fprintf(stderr, "hIST[%d]: %s: invalid frequency\n", i, params[i]);
+         exit(1);
+      }
+   }
+
+   png_set_hIST(png_ptr, info_ptr, freq);
+}
+
+static png_byte
+bval(png_const_structrp png_ptr, png_charp param, unsigned int maxval)
+{
+   char *endptr = NULL;
+   unsigned long int l = strtoul(param, &endptr, 0/*base*/);
+
+   if (param[0] && *endptr == 0 && l <= maxval)
+      return (png_byte)l;
+
+   else
+      png_error(png_ptr, "sBIT: invalid sBIT value");
+}
+
+static void
+insert_sBIT(png_structp png_ptr, png_infop info_ptr, int nparams,
+      png_charpp params)
+{
+   int ct = png_get_color_type(png_ptr, info_ptr);
+   int c = (ct & PNG_COLOR_MASK_COLOR ? 3 : 1) +
+      (ct & PNG_COLOR_MASK_ALPHA ? 1 : 0);
+   unsigned int maxval =
+      ct & PNG_COLOR_MASK_PALETTE ? 8U : png_get_bit_depth(png_ptr, info_ptr);
+   png_color_8 sBIT;
+
+   if (nparams != c)
+      png_error(png_ptr, "sBIT: incorrect parameter count");
+
+   if (ct & PNG_COLOR_MASK_COLOR)
+   {
+      sBIT.red = bval(png_ptr, params[0], maxval);
+      sBIT.green = bval(png_ptr, params[1], maxval);
+      sBIT.blue = bval(png_ptr, params[2], maxval);
+      sBIT.gray = 42;
+   }
+
+   else
+   {
+      sBIT.red = sBIT.green = sBIT.blue = 42;
+      sBIT.gray = bval(png_ptr, params[0], maxval);
+   }
+
+   if (ct & PNG_COLOR_MASK_ALPHA)
+      sBIT.alpha = bval(png_ptr, params[nparams-1], maxval);
+
+   else
+      sBIT.alpha = 42;
+
+   png_set_sBIT(png_ptr, info_ptr, &sBIT);
+}
+
+#if 0
+static void
+insert_sPLT(png_structp png_ptr, png_infop info_ptr, int nparams, png_charpp params)
+{
+   fprintf(stderr, "insert sPLT: NYI\n");
+}
+#endif
+
+static int
+find_parameters(png_const_charp what, png_charp param, png_charp *list,
+   int nparams)
+{
+   /* Parameters are separated by '\n' or ':' characters, up to nparams are
+    * accepted (more is an error) and the number found is returned.
+    */
+   int i;
+   for (i=0; *param && i<nparams; ++i)
+   {
+      list[i] = param;
+      while (*++param)
+      {
+         if (*param == '\n' || *param == ':')
+         {
+            *param++ = 0; /* Terminate last parameter */
+            break;        /* And start a new one. */
+         }
+      }
+   }
+
+   if (*param)
+   {
+      fprintf(stderr, "--insert %s: too many parameters (%s)\n", what, param);
+      exit(1);
+   }
+
+   list[i] = NULL; /* terminates list */
+   return i; /* number of parameters filled in */
+}
+
+static void
+bad_parameter_count(png_const_charp what, int nparams)
+{
+   fprintf(stderr, "--insert %s: bad parameter count %d\n", what, nparams);
+   exit(1);
+}
+
+static chunk_insert *
+make_insert(png_const_charp what,
+   void (*insert)(png_structp, png_infop, int, png_charpp),
+   int nparams, png_charpp list)
+{
+   int i;
+   chunk_insert *cip;
+
+   cip = malloc(offsetof(chunk_insert,parameters) +
+      nparams * sizeof (png_charp));
+
+   if (cip == NULL)
+   {
+      fprintf(stderr, "--insert %s: out of memory allocating %d parameters\n",
+         what, nparams);
+      exit(1);
+   }
+
+   cip->next = NULL;
+   cip->insert = insert;
+   cip->nparams = nparams;
+   for (i=0; i<nparams; ++i)
+      cip->parameters[i] = list[i];
+
+   return cip;
+}
+
+static chunk_insert *
+find_insert(png_const_charp what, png_charp param)
+{
+   png_uint_32 chunk = 0;
+   png_charp parameter_list[1024];
+   int i, nparams;
+
+   /* Assemble the chunk name */
+   for (i=0; i<4; ++i)
+   {
+      char ch = what[i];
+
+      if ((ch >= 65 && ch <= 90) || (ch >= 97 && ch <= 122))
+         chunk = (chunk << 8) + what[i];
+
+      else
+         break;
+   }
+
+   if (i < 4 || what[4] != 0)
+   {
+      fprintf(stderr, "makepng --insert \"%s\": invalid chunk name\n", what);
+      exit(1);
+   }
+
+   /* Assemble the parameter list. */
+   nparams = find_parameters(what, param, parameter_list, 1024);
+
+#  define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
+
+   switch (chunk)
+   {
+      case CHUNK(105,67,67,80):  /* iCCP */
+         if (nparams == 2)
+            return make_insert(what, insert_iCCP, nparams, parameter_list);
+         break;
+
+      case CHUNK(116,69,88,116): /* tEXt */
+         if (nparams == 2)
+            return make_insert(what, insert_tEXt, nparams, parameter_list);
+         break;
+
+      case CHUNK(122,84,88,116): /* zTXt */
+         if (nparams == 2)
+            return make_insert(what, insert_zTXt, nparams, parameter_list);
+         break;
+
+      case CHUNK(105,84,88,116): /* iTXt */
+         if (nparams == 4)
+            return make_insert(what, insert_iTXt, nparams, parameter_list);
+         break;
+
+      case CHUNK(104,73,83,84):  /* hIST */
+         if (nparams <= 256)
+            return make_insert(what, insert_hIST, nparams, parameter_list);
+         break;
+
+      case CHUNK(115,66,73,84): /* sBIT */
+         if (nparams <= 4)
+            return make_insert(what, insert_sBIT, nparams, parameter_list);
+         break;
+
+#if 0
+      case CHUNK(115,80,76,84):  /* sPLT */
+         return make_insert(what, insert_sPLT, nparams, parameter_list);
+#endif
+
+      default:
+         fprintf(stderr, "makepng --insert \"%s\": unrecognized chunk name\n",
+            what);
+         exit(1);
+   }
+
+   bad_parameter_count(what, nparams);
+   return NULL;
+}
+
+/* This is necessary because libpng expects writeable strings for things like
+ * text chunks (maybe this should be fixed...)
+ */
+static png_charp
+strstash(png_const_charp foo)
+{
+   /* The program indicates a memory allocation error by crashing, this is by
+    * design.
+    */
+   if (foo != NULL)
+   {
+      png_charp bar = malloc(strlen(foo)+1);
+      return strcpy(bar, foo);
+   }
+
+   return NULL;
+}
+
+static png_charp
+strstash_list(const png_const_charp *text)
+{
+   size_t foo = 0;
+   png_charp result, bar;
+   const png_const_charp *line = text;
+
+   while (*line != NULL)
+      foo += strlen(*line++);
+
+   result = bar = malloc(foo+1);
+
+   line = text;
+   while (*line != NULL)
+   {
+      foo = strlen(*line);
+      memcpy(bar, *line++, foo);
+      bar += foo;
+   }
+
+   *bar = 0;
+   return result;
+}
+
+/* These are used to insert Copyright and Licence fields, they allow the text to
+ * have \n unlike the --insert option.
+ */
+static chunk_insert *
+add_tEXt(const char *key, const png_const_charp *text)
+{
+   static char what[5] = { 116, 69, 88, 116, 0 };
+   png_charp parameter_list[3];
+
+   parameter_list[0] = strstash(key);
+   parameter_list[1] = strstash_list(text);
+   parameter_list[2] = NULL;
+
+   return make_insert(what, insert_tEXt, 2, parameter_list);
+}
+
+static chunk_insert *
+add_iTXt(const char *key, const char *language, const char *language_key,
+      const png_const_charp *text)
+{
+   static char what[5] = { 105, 84, 88, 116, 0 };
+   png_charp parameter_list[5];
+
+   parameter_list[0] = strstash(key);
+   parameter_list[1] = strstash(language);
+   parameter_list[2] = strstash(language_key);
+   parameter_list[3] = strstash_list(text);
+   parameter_list[4] = NULL;
+
+   return make_insert(what, insert_iTXt, 4, parameter_list);
+}
+
+/* This is a not-very-good parser for a sequence of numbers (including 0).  It
+ * doesn't accept some apparently valid things, but it accepts all the sensible
+ * combinations.
+ */
+static void
+parse_color(char *arg, unsigned int *colors)
+{
+   unsigned int ncolors = 0;
+
+   while (*arg && ncolors < 4)
+   {
+      char *ep = arg;
+
+      unsigned long ul = strtoul(arg, &ep, 0);
+
+      if (ul > 65535)
+      {
+         fprintf(stderr, "makepng --color=...'%s': too big\n", arg);
+         exit(1);
+      }
+
+      if (ep == arg)
+      {
+         fprintf(stderr, "makepng --color=...'%s': not a valid color\n", arg);
+         exit(1);
+      }
+
+      if (*ep) ++ep; /* skip a separator */
+      arg = ep;
+
+      colors[++ncolors] = (unsigned int)ul; /* checked above */
+   }
+
+   if (*arg)
+   {
+      fprintf(stderr, "makepng --color=...'%s': too many values\n", arg);
+      exit(1);
+   }
+
+   *colors = ncolors;
+}
+
+int
+main(int argc, char **argv)
+{
+   FILE *fp = stdout;
+   const char *file_name = NULL;
+   int color_type = 8; /* invalid */
+   int bit_depth = 32; /* invalid */
+   int small = 0; /* make full size images */
+   int tRNS = 0; /* don't output a tRNS chunk */
+   unsigned int colors[5];
+   unsigned int filters = PNG_ALL_FILTERS;
+   png_fixed_point gamma = 0; /* not set */
+   chunk_insert *head_insert = NULL;
+   chunk_insert **insert_ptr = &head_insert;
+
+   memset(colors, 0, sizeof colors);
+
+   while (--argc > 0)
+   {
+      char *arg = *++argv;
+
+      if (strcmp(arg, "--small") == 0)
+      {
+         small = 1;
+         continue;
+      }
+
+      if (strcmp(arg, "--tRNS") == 0)
+      {
+         tRNS = 1;
+         continue;
+      }
+
+      if (strcmp(arg, "--sRGB") == 0)
+      {
+         gamma = PNG_DEFAULT_sRGB;
+         continue;
+      }
+
+      if (strcmp(arg, "--linear") == 0)
+      {
+         gamma = PNG_FP_1;
+         continue;
+      }
+
+      if (strcmp(arg, "--1.8") == 0)
+      {
+         gamma = PNG_GAMMA_MAC_18;
+         continue;
+      }
+
+      if (strcmp(arg, "--nofilters") == 0)
+      {
+         filters = PNG_FILTER_NONE;
+         continue;
+      }
+
+      if (strncmp(arg, "--color=", 8) == 0)
+      {
+          parse_color(arg+8, colors);
+          continue;
+      }
+
+      if (argc >= 3 && strcmp(arg, "--insert") == 0)
+      {
+         png_const_charp what = *++argv;
+         png_charp param = *++argv;
+         chunk_insert *new_insert;
+
+         argc -= 2;
+
+         new_insert = find_insert(what, param);
+
+         if (new_insert != NULL)
+         {
+            *insert_ptr = new_insert;
+            insert_ptr = &new_insert->next;
+         }
+
+         continue;
+      }
+
+      if (arg[0] == '-')
+      {
+         fprintf(stderr, "makepng: %s: invalid option\n", arg);
+         exit(1);
+      }
+
+      if (strcmp(arg, "palette") == 0)
+      {
+         color_type = PNG_COLOR_TYPE_PALETTE;
+         continue;
+      }
+
+      if (strncmp(arg, "gray", 4) == 0)
+      {
+         if (arg[4] == 0)
+         {
+            color_type = PNG_COLOR_TYPE_GRAY;
+            continue;
+         }
+
+         else if (strcmp(arg+4, "a") == 0 ||
+            strcmp(arg+4, "alpha") == 0 ||
+            strcmp(arg+4, "-alpha") == 0)
+         {
+            color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+            continue;
+         }
+      }
+
+      if (strncmp(arg, "rgb", 3) == 0)
+      {
+         if (arg[3] == 0)
+         {
+            color_type = PNG_COLOR_TYPE_RGB;
+            continue;
+         }
+
+         else if (strcmp(arg+3, "a") == 0 ||
+            strcmp(arg+3, "alpha") == 0 ||
+            strcmp(arg+3, "-alpha") == 0)
+         {
+            color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+            continue;
+         }
+      }
+
+      if (color_type == 8 && isdigit(arg[0]))
+      {
+         color_type = atoi(arg);
+         if (color_type < 0 || color_type > 6 || color_type == 1 ||
+            color_type == 5)
+         {
+            fprintf(stderr, "makepng: %s: not a valid color type\n", arg);
+            exit(1);
+         }
+
+         continue;
+      }
+
+      if (bit_depth == 32 && isdigit(arg[0]))
+      {
+         bit_depth = atoi(arg);
+         if (bit_depth <= 0 || bit_depth > 16 ||
+            (bit_depth & -bit_depth) != bit_depth)
+         {
+            fprintf(stderr, "makepng: %s: not a valid bit depth\n", arg);
+            exit(1);
+         }
+
+         continue;
+      }
+
+      if (argc == 1) /* It's the file name */
+      {
+         fp = fopen(arg, "wb");
+         if (fp == NULL)
+         {
+            fprintf(stderr, "%s: %s: could not open\n", arg, strerror(errno));
+            exit(1);
+         }
+
+         file_name = arg;
+         continue;
+      }
+
+      fprintf(stderr, "makepng: %s: unknown argument\n", arg);
+      exit(1);
+   } /* argument while loop */
+
+   if (color_type == 8 || bit_depth == 32)
+   {
+      fprintf(stderr, "usage: makepng [--small] [--sRGB|--linear|--1.8] "
+         "[--color=...] color-type bit-depth [file-name]\n"
+         "  Make a test PNG file, by default writes to stdout.\n"
+         "  Other options are available, UTSL.\n");
+      exit(1);
+   }
+
+   /* Check the colors */
+   {
+      unsigned int lim = (color_type == PNG_COLOR_TYPE_PALETTE ? 255U :
+         (1U<<bit_depth)-1);
+      unsigned int i;
+
+      for (i=1; i<=colors[0]; ++i)
+         if (colors[i] > lim)
+         {
+            fprintf(stderr, "makepng: --color=...: %u out of range [0..%u]\n",
+               colors[i], lim);
+            exit(1);
+         }
+   }
+
+   /* small and colors are incompatible (will probably crash if both are used at
+    * the same time!)
+    */
+   if (small && colors[0] != 0)
+   {
+      fprintf(stderr, "makepng: --color --small: only one at a time!\n");
+      exit(1);
+   }
+
+   /* Restrict the filters for more speed to those we know are used for the
+    * generated images.
+    */
+   if (filters == PNG_ALL_FILTERS && !small/*small provides defaults*/)
+   {
+      if ((color_type & PNG_COLOR_MASK_PALETTE) != 0 || bit_depth < 8)
+         filters = PNG_FILTER_NONE;
+
+      else if (color_type & PNG_COLOR_MASK_COLOR) /* rgb */
+      {
+         if (bit_depth == 8)
+            filters &= ~(PNG_FILTER_NONE | PNG_FILTER_AVG);
+
+         else
+            filters = PNG_FILTER_SUB | PNG_FILTER_PAETH;
+      }
+
+      else /* gray 8 or 16-bit */
+         filters &= ~PNG_FILTER_NONE;
+   }
+
+   /* Insert standard copyright and licence text. */
+   {
+      static png_const_charp copyright[] =
+      {
+         COPYRIGHT, /* ISO-Latin-1 */
+         NULL
+      };
+      static png_const_charp licensing[] =
+      {
+         IMAGE_LICENSING, /* UTF-8 */
+         NULL
+      };
+
+      chunk_insert *new_insert;
+
+      new_insert = add_tEXt("Copyright", copyright);
+      if (new_insert != NULL)
+      {
+         *insert_ptr = new_insert;
+         insert_ptr = &new_insert->next;
+      }
+
+      new_insert = add_iTXt("Licensing", "en", NULL, licensing);
+      if (new_insert != NULL)
+      {
+         *insert_ptr = new_insert;
+         insert_ptr = &new_insert->next;
+      }
+   }
+
+   {
+      int ret = write_png(&file_name, fp, color_type, bit_depth, gamma,
+         head_insert, filters, colors, small, tRNS);
+
+      if (ret != 0 && file_name != NULL)
+         remove(file_name);
+
+      return ret;
+   }
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngimage.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngimage.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngimage.c	(revision 107811)
@@ -0,0 +1,1722 @@
+
+/* pngimage.c
+ *
+ * Copyright (c) 2021 Cosmin Truta
+ * Copyright (c) 2015,2016 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Test the png_read_png and png_write_png interfaces.  Given a PNG file load it
+ * using png_read_png and then write with png_write_png.  Test all possible
+ * transforms.
+ */
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdio.h>
+#include <assert.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#ifndef PNG_SETJMP_SUPPORTED
+#  include <setjmp.h> /* because png.h did *not* include this */
+#endif
+
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+   /* READ_PNG and WRITE_PNG were not defined, so: */
+#  ifdef PNG_INFO_IMAGE_SUPPORTED
+#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#        define PNG_READ_PNG_SUPPORTED
+#     endif /* SEQUENTIAL_READ */
+#     ifdef PNG_WRITE_SUPPORTED
+#        define PNG_WRITE_PNG_SUPPORTED
+#     endif /* WRITE */
+#  endif /* INFO_IMAGE */
+#endif /* pre 1.7.0 */
+
+#ifdef PNG_READ_PNG_SUPPORTED
+/* If a transform is valid on both read and write this implies that if the
+ * transform is applied to read it must also be applied on write to produce
+ * meaningful data.  This is because these transforms when performed on read
+ * produce data with a memory format that does not correspond to a PNG format.
+ *
+ * Most of these transforms are invertible; after applying the transform on
+ * write the result is the original PNG data that would have would have been
+ * read if no transform were applied.
+ *
+ * The exception is _SHIFT, which destroys the low order bits marked as not
+ * significant in a PNG with the sBIT chunk.
+ *
+ * The following table lists, for each transform, the conditions under which it
+ * is expected to do anything.  Conditions are defined as follows:
+ *
+ * 1) Color mask bits required - simply a mask to AND with color_type; one of
+ *    these must be present for the transform to fire, except that 0 means
+ *    'always'.
+ * 2) Color mask bits which must be absent - another mask - none of these must
+ *    be present.
+ * 3) Bit depths - a mask of component bit depths for the transform to fire.
+ * 4) 'read' - the transform works in png_read_png.
+ * 5) 'write' - the transform works in png_write_png.
+ * 6) PNG_INFO_chunk; a mask of the chunks that must be present for the
+ *    transform to fire.  All must be present - the requirement is that
+ *    png_get_valid() & mask == mask, so if mask is 0 there is no requirement.
+ *
+ * The condition refers to the original image state - if multiple transforms are
+ * used together it is possible to cause a transform that wouldn't fire on the
+ * original image to fire.
+ */
+static struct transform_info
+{
+   const char *name;
+   int         transform;
+   png_uint_32 valid_chunks;
+#     define CHUNK_NONE 0
+#     define CHUNK_sBIT PNG_INFO_sBIT
+#     define CHUNK_tRNS PNG_INFO_tRNS
+   png_byte    color_mask_required;
+   png_byte    color_mask_absent;
+#     define COLOR_MASK_X   0
+#     define COLOR_MASK_P   PNG_COLOR_MASK_PALETTE
+#     define COLOR_MASK_C   PNG_COLOR_MASK_COLOR
+#     define COLOR_MASK_A   PNG_COLOR_MASK_ALPHA
+#     define COLOR_MASK_ALL (PALETTE+COLOR+ALPHA)  /* absent = gray, no alpha */
+   png_byte    bit_depths;
+#     define BD_ALL  (1 + 2 + 4 + 8 + 16)
+#     define BD_PAL  (1 + 2 + 4 + 8)
+#     define BD_LOW  (1 + 2 + 4)
+#     define BD_16   16
+#     define BD_TRUE (8+16) /* i.e. true-color depths */
+   png_byte    when;
+#     define TRANSFORM_R  1
+#     define TRANSFORM_W  2
+#     define TRANSFORM_RW 3
+   png_byte    tested; /* the transform was tested somewhere */
+} transform_info[] =
+{
+   /* List ALL the PNG_TRANSFORM_ macros here.  Check for support using the READ
+    * macros; even if the transform is supported on write it cannot be tested
+    * without the read support.
+    */
+#  define T(name,chunk,cm_required,cm_absent,bd,when)\
+   {  #name, PNG_TRANSFORM_ ## name, CHUNK_ ## chunk,\
+      COLOR_MASK_ ## cm_required, COLOR_MASK_ ## cm_absent, BD_ ## bd,\
+      TRANSFORM_ ## when, 0/*!tested*/ }
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+   T(STRIP_16,            NONE, X,   X,   16,  R),
+      /* drops the bottom 8 bits when bit depth is 16 */
+#endif
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   T(STRIP_ALPHA,         NONE, A,   X,  ALL,  R),
+      /* removes the alpha channel if present */
+#endif
+#ifdef PNG_WRITE_PACK_SUPPORTED
+#  define TRANSFORM_RW_PACK TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_PACK TRANSFORM_R
+#endif
+#ifdef PNG_READ_PACK_SUPPORTED
+   T(PACKING,             NONE, X,   X,  LOW, RW_PACK),
+      /* unpacks low-bit-depth components into 1 byte per component on read,
+       * reverses this on write.
+       */
+#endif
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+#  define TRANSFORM_RW_PACKSWAP TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_PACKSWAP TRANSFORM_R
+#endif
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+   T(PACKSWAP,            NONE, X,   X,  LOW, RW_PACKSWAP),
+      /* reverses the order of low-bit-depth components packed into a byte */
+#endif
+#ifdef PNG_READ_EXPAND_SUPPORTED
+   T(EXPAND,              NONE, P,   X,  ALL,  R),
+      /* expands PLTE PNG files to RGB (no tRNS) or RGBA (tRNS) *
+       * Note that the 'EXPAND' transform does lots of different things: */
+   T(EXPAND,              NONE, X,   C,  ALL,  R),
+      /* expands grayscale PNG files to RGB, or RGBA */
+   T(EXPAND,              tRNS, X,   A,  ALL,  R),
+      /* expands the tRNS chunk in files without alpha */
+#endif
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+#  define TRANSFORM_RW_INVERT TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_INVERT TRANSFORM_R
+#endif
+#ifdef PNG_READ_INVERT_SUPPORTED
+   T(INVERT_MONO,         NONE, X,   C,  ALL, RW_INVERT),
+      /* converts gray-scale components to 1..0 from 0..1 */
+#endif
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+#  define TRANSFORM_RW_SHIFT TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_SHIFT TRANSFORM_R
+#endif
+#ifdef PNG_READ_SHIFT_SUPPORTED
+   T(SHIFT,               sBIT, X,   X,  ALL, RW_SHIFT),
+      /* reduces component values to the original range based on the sBIT chunk,
+       * this is only partially reversible - the low bits are lost and cannot be
+       * recovered on write.  In fact write code replicates the bits to generate
+       * new low-order bits.
+       */
+#endif
+#ifdef PNG_WRITE_BGR_SUPPORTED
+#  define TRANSFORM_RW_BGR TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_BGR TRANSFORM_R
+#endif
+#ifdef PNG_READ_BGR_SUPPORTED
+   T(BGR,                 NONE, C,   P, TRUE, RW_BGR),
+      /* reverses the rgb component values of true-color pixels */
+#endif
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+#  define TRANSFORM_RW_SWAP_ALPHA TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_SWAP_ALPHA TRANSFORM_R
+#endif
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+   T(SWAP_ALPHA,          NONE, A,   X, TRUE, RW_SWAP_ALPHA),
+      /* swaps the alpha channel of RGBA or GA pixels to the front - ARGB or
+       * AG, on write reverses the process.
+       */
+#endif
+#ifdef PNG_WRITE_SWAP_SUPPORTED
+#  define TRANSFORM_RW_SWAP TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_SWAP TRANSFORM_R
+#endif
+#ifdef PNG_READ_SWAP_SUPPORTED
+   T(SWAP_ENDIAN,         NONE, X,   P,   16, RW_SWAP),
+      /* byte-swaps 16-bit component values */
+#endif
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+#  define TRANSFORM_RW_INVERT_ALPHA TRANSFORM_RW
+#else
+#  define TRANSFORM_RW_INVERT_ALPHA TRANSFORM_R
+#endif
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+   T(INVERT_ALPHA,        NONE, A,   X, TRUE, RW_INVERT_ALPHA),
+      /* converts an alpha channel from 0..1 to 1..0 */
+#endif
+#ifdef PNG_WRITE_FILLER_SUPPORTED
+   T(STRIP_FILLER_BEFORE, NONE, A,   P, TRUE,  W), /* 'A' for a filler! */
+      /* on write skips a leading filler channel; testing requires data with a
+       * filler channel so this is produced from RGBA or GA images by removing
+       * the 'alpha' flag from the color type in place.
+       */
+   T(STRIP_FILLER_AFTER,  NONE, A,   P, TRUE,  W),
+      /* on write strips a trailing filler channel */
+#endif
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   T(GRAY_TO_RGB,         NONE, X,   C,  ALL,  R),
+      /* expands grayscale images to RGB, also causes the palette part of
+       * 'EXPAND' to happen.  Low bit depth grayscale images are expanded to
+       * 8-bits per component and no attempt is made to convert the image to a
+       * palette image.  While this transform is partially reversible
+       * png_write_png does not currently support this.
+       */
+   T(GRAY_TO_RGB,         NONE, P,   X,  ALL,  R),
+      /* The 'palette' side effect mentioned above; a bit bogus but this is the
+       * way the libpng code works.
+       */
+#endif
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   T(EXPAND_16,           NONE, X,   X,  PAL,  R),
+      /* expands images to 16-bits per component, as a side effect expands
+       * palette images to RGB and expands the tRNS chunk if present, so it can
+       * modify 16-bit per component images as well:
+       */
+   T(EXPAND_16,           tRNS, X,   A,   16,  R),
+      /* side effect of EXPAND_16 - expands the tRNS chunk in an RGB or G 16-bit
+       * image.
+       */
+#endif
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+   T(SCALE_16,            NONE, X,   X,   16,  R),
+      /* scales 16-bit components to 8-bits. */
+#endif
+
+   { NULL /*name*/, 0, 0, 0, 0, 0, 0, 0/*!tested*/ }
+
+#undef T
+};
+
+#define ARRAY_SIZE(a) ((sizeof a)/(sizeof a[0]))
+#define TTABLE_SIZE ARRAY_SIZE(transform_info)
+
+/* Some combinations of options that should be reversible are not; these cases
+ * are bugs.
+ */
+static int known_bad_combos[][2] =
+{
+   /* problem, antidote */
+   { PNG_TRANSFORM_SHIFT | PNG_TRANSFORM_INVERT_ALPHA, 0/*antidote*/ }
+};
+
+static int
+is_combo(int transforms)
+{
+   return transforms & (transforms-1); /* non-zero if more than one set bit */
+}
+
+static int
+first_transform(int transforms)
+{
+   return transforms & -transforms; /* lowest set bit */
+}
+
+static int
+is_bad_combo(int transforms)
+{
+   unsigned int i;
+
+   for (i=0; i<ARRAY_SIZE(known_bad_combos); ++i)
+   {
+      int combo = known_bad_combos[i][0];
+
+      if ((combo & transforms) == combo &&
+         (transforms & known_bad_combos[i][1]) == 0)
+         return 1;
+   }
+
+   return 0; /* combo is ok */
+}
+
+static const char *
+transform_name(int t)
+   /* The name, if 't' has multiple bits set the name of the lowest set bit is
+    * returned.
+    */
+{
+   unsigned int i;
+
+   t &= -t; /* first set bit */
+
+   for (i=0; i<TTABLE_SIZE; ++i)
+      if (transform_info[i].name != NULL)
+         if ((transform_info[i].transform & t) != 0)
+            return transform_info[i].name;
+
+   return "invalid transform";
+}
+
+/* Variables calculated by validate_T below and used to record all the supported
+ * transforms.  Need (unsigned int) here because of the places where these
+ * values are used (unsigned compares in the 'exhaustive' iterator.)
+ */
+static unsigned int read_transforms, write_transforms, rw_transforms;
+
+static void
+validate_T(void)
+   /* Validate the above table - this just builds the above values */
+{
+   unsigned int i;
+
+   for (i=0; i<TTABLE_SIZE; ++i)
+   {
+      if (transform_info[i].name != NULL)
+      {
+         if (transform_info[i].when & TRANSFORM_R)
+            read_transforms |= transform_info[i].transform;
+
+         if (transform_info[i].when & TRANSFORM_W)
+            write_transforms |= transform_info[i].transform;
+      }
+   }
+
+   /* Reversible transforms are those which are supported on both read and
+    * write.
+    */
+   rw_transforms = read_transforms & write_transforms;
+}
+
+/* FILE DATA HANDLING
+ *    The original file is cached in memory.  During write the output file is
+ *    written to memory.
+ *
+ *    In both cases the file data is held in a linked list of buffers - not all
+ *    of these are in use at any time.
+ */
+#define NEW(type) ((type *)malloc(sizeof (type)))
+#define DELETE(ptr) (free(ptr))
+
+struct buffer_list
+{
+   struct buffer_list *next;         /* next buffer in list */
+   png_byte            buffer[1024]; /* the actual buffer */
+};
+
+struct buffer
+{
+   struct buffer_list  *last;       /* last buffer in use */
+   size_t               end_count;  /* bytes in the last buffer */
+   struct buffer_list  *current;    /* current buffer being read */
+   size_t               read_count; /* count of bytes read from current */
+   struct buffer_list   first;      /* the very first buffer */
+};
+
+static void
+buffer_init(struct buffer *buffer)
+   /* Call this only once for a given buffer */
+{
+   buffer->first.next = NULL;
+   buffer->last = NULL;
+   buffer->current = NULL;
+}
+
+static void
+buffer_destroy_list(struct buffer_list *list)
+{
+   if (list != NULL)
+   {
+      struct buffer_list *next = list->next;
+      DELETE(list);
+      buffer_destroy_list(next);
+   }
+}
+
+static void
+buffer_destroy(struct buffer *buffer)
+{
+   struct buffer_list *list = buffer->first.next;
+   buffer_init(buffer);
+   buffer_destroy_list(list);
+}
+
+#ifdef PNG_WRITE_PNG_SUPPORTED
+static void
+buffer_start_write(struct buffer *buffer)
+{
+   buffer->last = &buffer->first;
+   buffer->end_count = 0;
+   buffer->current = NULL;
+}
+#endif
+
+static void
+buffer_start_read(struct buffer *buffer)
+{
+   buffer->current = &buffer->first;
+   buffer->read_count = 0;
+}
+
+#ifdef ENOMEM /* required by POSIX 1003.1 */
+#  define MEMORY ENOMEM
+#else
+#  define MEMORY ERANGE /* required by ANSI-C */
+#endif
+static struct buffer *
+get_buffer(png_structp pp)
+   /* Used from libpng callbacks to get the current buffer */
+{
+   return (struct buffer*)png_get_io_ptr(pp);
+}
+
+static struct buffer_list *
+buffer_extend(struct buffer_list *current)
+{
+   struct buffer_list *add;
+
+   assert(current->next == NULL);
+
+   add = NEW(struct buffer_list);
+   if (add == NULL)
+      return NULL;
+
+   add->next = NULL;
+   current->next = add;
+
+   return add;
+}
+
+/* Load a buffer from a file; does the equivalent of buffer_start_write.  On a
+ * read error returns an errno value, else returns 0.
+ */
+static int
+buffer_from_file(struct buffer *buffer, FILE *fp)
+{
+   struct buffer_list *last = &buffer->first;
+   size_t count = 0;
+
+   for (;;)
+   {
+      size_t r = fread(last->buffer+count, 1/*size*/,
+         (sizeof last->buffer)-count, fp);
+
+      if (r > 0)
+      {
+         count += r;
+
+         if (count >= sizeof last->buffer)
+         {
+            assert(count == sizeof last->buffer);
+            count = 0;
+
+            if (last->next == NULL)
+            {
+               last = buffer_extend(last);
+               if (last == NULL)
+                  return MEMORY;
+            }
+
+            else
+               last = last->next;
+         }
+      }
+
+      else /* fread failed - probably end of file */
+      {
+         if (feof(fp))
+         {
+            buffer->last = last;
+            buffer->end_count = count;
+            return 0; /* no error */
+         }
+
+         /* Some kind of funky error; errno should be non-zero */
+         return errno == 0 ? ERANGE : errno;
+      }
+   }
+}
+
+/* This structure is used to control the test of a single file. */
+typedef enum
+{
+   VERBOSE,        /* switches on all messages */
+   INFORMATION,
+   WARNINGS,       /* switches on warnings */
+   LIBPNG_WARNING,
+   APP_WARNING,
+   ERRORS,         /* just errors */
+   APP_FAIL,       /* continuable error - no need to longjmp */
+   LIBPNG_ERROR,   /* this and higher cause a longjmp */
+   LIBPNG_BUG,     /* erroneous behavior in libpng */
+   APP_ERROR,      /* such as out-of-memory in a callback */
+   QUIET,          /* no normal messages */
+   USER_ERROR,     /* such as file-not-found */
+   INTERNAL_ERROR
+} error_level;
+#define LEVEL_MASK      0xf   /* where the level is in 'options' */
+
+#define EXHAUSTIVE      0x010 /* Test all combinations of active options */
+#define STRICT          0x020 /* Fail on warnings as well as errors */
+#define LOG             0x040 /* Log pass/fail to stdout */
+#define CONTINUE        0x080 /* Continue on APP_FAIL errors */
+#define SKIP_BUGS       0x100 /* Skip over known bugs */
+#define LOG_SKIPPED     0x200 /* Log skipped bugs */
+#define FIND_BAD_COMBOS 0x400 /* Attempt to deduce bad combos */
+#define LIST_COMBOS     0x800 /* List combos by name */
+
+/* Result masks apply to the result bits in the 'results' field below; these
+ * bits are simple 1U<<error_level.  A pass requires either nothing worse than
+ * warnings (--relaxes) or nothing worse than information (--strict)
+ */
+#define RESULT_STRICT(r)   (((r) & ~((1U<<WARNINGS)-1)) == 0)
+#define RESULT_RELAXED(r)  (((r) & ~((1U<<ERRORS)-1)) == 0)
+
+struct display
+{
+   jmp_buf        error_return;      /* Where to go to on error */
+
+   const char    *filename;          /* The name of the original file */
+   const char    *operation;         /* Operation being performed */
+   int            transforms;        /* Transform used in operation */
+   png_uint_32    options;           /* See display_log below */
+   png_uint_32    results;           /* A mask of errors seen */
+
+
+   png_structp    original_pp;       /* used on the original read */
+   png_infop      original_ip;       /* set by the original read */
+
+   size_t         original_rowbytes; /* of the original rows: */
+   png_bytepp     original_rows;     /* from the original read */
+
+   /* Original chunks valid */
+   png_uint_32    chunks;
+
+   /* Original IHDR information */
+   png_uint_32    width;
+   png_uint_32    height;
+   int            bit_depth;
+   int            color_type;
+   int            interlace_method;
+   int            compression_method;
+   int            filter_method;
+
+   /* Derived information for the original image. */
+   int            active_transforms;  /* transforms that do something on read */
+   int            ignored_transforms; /* transforms that should do nothing */
+
+   /* Used on a read, both the original read and when validating a written
+    * image.
+    */
+   png_structp    read_pp;
+   png_infop      read_ip;
+
+#  ifdef PNG_WRITE_PNG_SUPPORTED
+      /* Used to write a new image (the original info_ptr is used) */
+      png_structp   write_pp;
+      struct buffer written_file;   /* where the file gets written */
+#  endif
+
+   struct buffer  original_file;     /* Data read from the original file */
+};
+
+static void
+display_init(struct display *dp)
+   /* Call this only once right at the start to initialize the control
+    * structure, the (struct buffer) lists are maintained across calls - the
+    * memory is not freed.
+    */
+{
+   memset(dp, 0, sizeof *dp);
+   dp->options = WARNINGS; /* default to !verbose, !quiet */
+   dp->filename = NULL;
+   dp->operation = NULL;
+   dp->original_pp = NULL;
+   dp->original_ip = NULL;
+   dp->original_rows = NULL;
+   dp->read_pp = NULL;
+   dp->read_ip = NULL;
+   buffer_init(&dp->original_file);
+
+#  ifdef PNG_WRITE_PNG_SUPPORTED
+      dp->write_pp = NULL;
+      buffer_init(&dp->written_file);
+#  endif
+}
+
+static void
+display_clean_read(struct display *dp)
+{
+   if (dp->read_pp != NULL)
+      png_destroy_read_struct(&dp->read_pp, &dp->read_ip, NULL);
+}
+
+#ifdef PNG_WRITE_PNG_SUPPORTED
+static void
+display_clean_write(struct display *dp)
+{
+      if (dp->write_pp != NULL)
+         png_destroy_write_struct(&dp->write_pp, NULL);
+}
+#endif
+
+static void
+display_clean(struct display *dp)
+{
+#  ifdef PNG_WRITE_PNG_SUPPORTED
+      display_clean_write(dp);
+#  endif
+   display_clean_read(dp);
+
+   dp->original_rowbytes = 0;
+   dp->original_rows = NULL;
+   dp->chunks = 0;
+
+   png_destroy_read_struct(&dp->original_pp, &dp->original_ip, NULL);
+   /* leave the filename for error detection */
+   dp->results = 0; /* reset for next time */
+}
+
+static void
+display_destroy(struct display *dp)
+{
+    /* Release any memory held in the display. */
+#  ifdef PNG_WRITE_PNG_SUPPORTED
+      buffer_destroy(&dp->written_file);
+#  endif
+
+   buffer_destroy(&dp->original_file);
+}
+
+static struct display *
+get_dp(png_structp pp)
+   /* The display pointer is always stored in the png_struct error pointer */
+{
+   struct display *dp = (struct display*)png_get_error_ptr(pp);
+
+   if (dp == NULL)
+   {
+      fprintf(stderr, "pngimage: internal error (no display)\n");
+      exit(99); /* prevents a crash */
+   }
+
+   return dp;
+}
+
+/* error handling */
+#ifdef __GNUC__
+#  define VGATTR __attribute__((__format__ (__printf__,3,4)))
+   /* Required to quiet GNUC warnings when the compiler sees a stdarg function
+    * that calls one of the stdio v APIs.
+    */
+#else
+#  define VGATTR
+#endif
+static void VGATTR
+display_log(struct display *dp, error_level level, const char *fmt, ...)
+   /* 'level' is as above, fmt is a stdio style format string.  This routine
+    * does not return if level is above LIBPNG_WARNING
+    */
+{
+   dp->results |= 1U << level;
+
+   if (level > (error_level)(dp->options & LEVEL_MASK))
+   {
+      const char *lp;
+      va_list ap;
+
+      switch (level)
+      {
+         case INFORMATION:    lp = "information"; break;
+         case LIBPNG_WARNING: lp = "warning(libpng)"; break;
+         case APP_WARNING:    lp = "warning(pngimage)"; break;
+         case APP_FAIL:       lp = "error(continuable)"; break;
+         case LIBPNG_ERROR:   lp = "error(libpng)"; break;
+         case LIBPNG_BUG:     lp = "bug(libpng)"; break;
+         case APP_ERROR:      lp = "error(pngimage)"; break;
+         case USER_ERROR:     lp = "error(user)"; break;
+
+         case INTERNAL_ERROR: /* anything unexpected is an internal error: */
+         case VERBOSE: case WARNINGS: case ERRORS: case QUIET:
+         default:             lp = "bug(pngimage)"; break;
+      }
+
+      fprintf(stderr, "%s: %s: %s",
+         dp->filename != NULL ? dp->filename : "<stdin>", lp, dp->operation);
+
+      if (dp->transforms != 0)
+      {
+         int tr = dp->transforms;
+
+         if (is_combo(tr))
+         {
+            if (dp->options & LIST_COMBOS)
+            {
+               int trx = tr;
+
+               fprintf(stderr, "(");
+               if (trx)
+               {
+                  int start = 0;
+
+                  while (trx)
+                  {
+                     int trz = trx & -trx;
+
+                     if (start) fprintf(stderr, "+");
+                     fprintf(stderr, "%s", transform_name(trz));
+                     start = 1;
+                     trx &= ~trz;
+                  }
+               }
+
+               else
+                  fprintf(stderr, "-");
+               fprintf(stderr, ")");
+            }
+
+            else
+               fprintf(stderr, "(0x%x)", tr);
+         }
+
+         else
+            fprintf(stderr, "(%s)", transform_name(tr));
+      }
+
+      fprintf(stderr, ": ");
+
+      va_start(ap, fmt);
+      vfprintf(stderr, fmt, ap);
+      va_end(ap);
+
+      fputc('\n', stderr);
+   }
+   /* else do not output any message */
+
+   /* Errors cause this routine to exit to the fail code */
+   if (level > APP_FAIL || (level > ERRORS && !(dp->options & CONTINUE)))
+      longjmp(dp->error_return, level);
+}
+
+/* error handler callbacks for libpng */
+static void PNGCBAPI
+display_warning(png_structp pp, png_const_charp warning)
+{
+   display_log(get_dp(pp), LIBPNG_WARNING, "%s", warning);
+}
+
+static void PNGCBAPI
+display_error(png_structp pp, png_const_charp error)
+{
+   struct display *dp = get_dp(pp);
+
+   display_log(dp, LIBPNG_ERROR, "%s", error);
+}
+
+static void
+display_cache_file(struct display *dp, const char *filename)
+   /* Does the initial cache of the file. */
+{
+   FILE *fp;
+   int ret;
+
+   dp->filename = filename;
+
+   if (filename != NULL)
+   {
+      fp = fopen(filename, "rb");
+      if (fp == NULL)
+         display_log(dp, USER_ERROR, "open failed: %s", strerror(errno));
+   }
+
+   else
+      fp = stdin;
+
+   ret = buffer_from_file(&dp->original_file, fp);
+
+   fclose(fp);
+
+   if (ret != 0)
+      display_log(dp, APP_ERROR, "read failed: %s", strerror(ret));
+}
+
+static void
+buffer_read(struct display *dp, struct buffer *bp, png_bytep data,
+   size_t size)
+{
+   struct buffer_list *last = bp->current;
+   size_t read_count = bp->read_count;
+
+   while (size > 0)
+   {
+      size_t avail;
+
+      if (last == NULL ||
+         (last == bp->last && read_count >= bp->end_count))
+      {
+         display_log(dp, USER_ERROR, "file truncated (%lu bytes)",
+            (unsigned long)size);
+         /*NOTREACHED*/
+         break;
+      }
+
+      else if (read_count >= sizeof last->buffer)
+      {
+         /* Move to the next buffer: */
+         last = last->next;
+         read_count = 0;
+         bp->current = last; /* Avoid update outside the loop */
+
+         /* And do a sanity check (the EOF case is caught above) */
+         if (last == NULL)
+         {
+            display_log(dp, INTERNAL_ERROR, "damaged buffer list");
+            /*NOTREACHED*/
+            break;
+         }
+      }
+
+      avail = (sizeof last->buffer) - read_count;
+      if (avail > size)
+         avail = size;
+
+      memcpy(data, last->buffer + read_count, avail);
+      read_count += avail;
+      size -= avail;
+      data += avail;
+   }
+
+   bp->read_count = read_count;
+}
+
+static void PNGCBAPI
+read_function(png_structp pp, png_bytep data, size_t size)
+{
+   buffer_read(get_dp(pp), get_buffer(pp), data, size);
+}
+
+static void
+read_png(struct display *dp, struct buffer *bp, const char *operation,
+   int transforms)
+{
+   png_structp pp;
+   png_infop   ip;
+
+   /* This cleans out any previous read and sets operation and transforms to
+    * empty.
+    */
+   display_clean_read(dp);
+
+   if (operation != NULL) /* else this is a verify and do not overwrite info */
+   {
+      dp->operation = operation;
+      dp->transforms = transforms;
+   }
+
+   dp->read_pp = pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, dp,
+      display_error, display_warning);
+   if (pp == NULL)
+      display_log(dp, LIBPNG_ERROR, "failed to create read struct");
+
+   /* The png_read_png API requires us to make the info struct, but it does the
+    * call to png_read_info.
+    */
+   dp->read_ip = ip = png_create_info_struct(pp);
+   if (ip == NULL)
+      display_log(dp, LIBPNG_ERROR, "failed to create info struct");
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      /* Remove the user limits, if any */
+      png_set_user_limits(pp, 0x7fffffff, 0x7fffffff);
+#  endif
+
+   /* Set the IO handling */
+   buffer_start_read(bp);
+   png_set_read_fn(pp, bp, read_function);
+
+   png_read_png(pp, ip, transforms, NULL/*params*/);
+
+#if 0 /* crazy debugging */
+   {
+      png_bytep pr = png_get_rows(pp, ip)[0];
+      size_t rb = png_get_rowbytes(pp, ip);
+      size_t cb;
+      char c = ' ';
+
+      fprintf(stderr, "%.4x %2d (%3lu bytes):", transforms, png_get_bit_depth(pp,ip), (unsigned long)rb);
+
+      for (cb=0; cb<rb; ++cb)
+         fputc(c, stderr), fprintf(stderr, "%.2x", pr[cb]), c='.';
+
+      fputc('\n', stderr);
+   }
+#endif
+}
+
+static void
+update_display(struct display *dp)
+   /* called once after the first read to update all the info, original_pp and
+    * original_ip must have been filled in.
+    */
+{
+   png_structp pp;
+   png_infop   ip;
+
+   /* Now perform the initial read with a 0 transform. */
+   read_png(dp, &dp->original_file, "original read", 0/*no transform*/);
+
+   /* Move the result to the 'original' fields */
+   dp->original_pp = pp = dp->read_pp, dp->read_pp = NULL;
+   dp->original_ip = ip = dp->read_ip, dp->read_ip = NULL;
+
+   dp->original_rowbytes = png_get_rowbytes(pp, ip);
+   if (dp->original_rowbytes == 0)
+      display_log(dp, LIBPNG_BUG, "png_get_rowbytes returned 0");
+
+   dp->chunks = png_get_valid(pp, ip, 0xffffffff);
+   if ((dp->chunks & PNG_INFO_IDAT) == 0) /* set by png_read_png */
+      display_log(dp, LIBPNG_BUG, "png_read_png did not set IDAT flag");
+
+   dp->original_rows = png_get_rows(pp, ip);
+   if (dp->original_rows == NULL)
+      display_log(dp, LIBPNG_BUG, "png_read_png did not create row buffers");
+
+   if (!png_get_IHDR(pp, ip,
+      &dp->width, &dp->height, &dp->bit_depth, &dp->color_type,
+      &dp->interlace_method, &dp->compression_method, &dp->filter_method))
+      display_log(dp, LIBPNG_BUG, "png_get_IHDR failed");
+
+   /* 'active' transforms are discovered based on the original image format;
+    * running one active transform can activate others.  At present the code
+    * does not attempt to determine the closure.
+    */
+   {
+      png_uint_32 chunks = dp->chunks;
+      int active = 0, inactive = 0;
+      int ct = dp->color_type;
+      int bd = dp->bit_depth;
+      unsigned int i;
+
+      for (i=0; i<TTABLE_SIZE; ++i)
+      {
+         if (transform_info[i].name != NULL)
+         {
+            int transform = transform_info[i].transform;
+
+            if ((transform_info[i].valid_chunks == 0 ||
+                  (transform_info[i].valid_chunks & chunks) != 0) &&
+               (transform_info[i].color_mask_required & ct) ==
+                  transform_info[i].color_mask_required &&
+               (transform_info[i].color_mask_absent & ct) == 0 &&
+               (transform_info[i].bit_depths & bd) != 0 &&
+               (transform_info[i].when & TRANSFORM_R) != 0)
+               active |= transform;
+
+            else if ((transform_info[i].when & TRANSFORM_R) != 0)
+               inactive |= transform;
+         }
+      }
+
+      /* Some transforms appear multiple times in the table; the 'active' status
+       * is the logical OR of these and the inactive status must be adjusted to
+       * take this into account.
+       */
+      inactive &= ~active;
+
+      dp->active_transforms = active;
+      dp->ignored_transforms = inactive; /* excluding write-only transforms */
+   }
+}
+
+static int
+compare_read(struct display *dp, int applied_transforms)
+{
+   /* Compare the png_info from read_ip with original_info */
+   size_t rowbytes;
+   png_uint_32 width, height;
+   int bit_depth, color_type;
+   int interlace_method, compression_method, filter_method;
+   const char *e = NULL;
+
+   if (!png_get_IHDR(dp->read_pp, dp->read_ip, &width, &height, &bit_depth,
+      &color_type, &interlace_method, &compression_method, &filter_method))
+      display_log(dp, LIBPNG_BUG, "png_get_IHDR failed");
+
+#  define C(item) if (item != dp->item) \
+      display_log(dp, APP_WARNING, "IHDR " #item "(%lu) changed to %lu",\
+         (unsigned long)dp->item, (unsigned long)item), e = #item
+
+   /* The IHDR should be identical: */
+   C(width);
+   C(height);
+   C(bit_depth);
+   C(color_type);
+   C(interlace_method);
+   C(compression_method);
+   C(filter_method);
+
+   /* 'e' remains set to the name of the last thing changed: */
+   if (e)
+      display_log(dp, APP_ERROR, "IHDR changed (%s)", e);
+
+   /* All the chunks from the original PNG should be preserved in the output PNG
+    * because the PNG format has not been changed.
+    */
+   {
+      unsigned long chunks =
+         png_get_valid(dp->read_pp, dp->read_ip, 0xffffffff);
+
+      if (chunks != dp->chunks)
+         display_log(dp, APP_FAIL, "PNG chunks changed from 0x%lx to 0x%lx",
+            (unsigned long)dp->chunks, chunks);
+   }
+
+   /* rowbytes should be the same */
+   rowbytes = png_get_rowbytes(dp->read_pp, dp->read_ip);
+
+   /* NOTE: on 64-bit systems this may trash the top bits of rowbytes,
+    * which could lead to weird error messages.
+    */
+   if (rowbytes != dp->original_rowbytes)
+      display_log(dp, APP_ERROR, "PNG rowbytes changed from %lu to %lu",
+         (unsigned long)dp->original_rowbytes, (unsigned long)rowbytes);
+
+   /* The rows should be the same too, unless the applied transforms includes
+    * the shift transform, in which case low bits may have been lost.
+    */
+   {
+      png_bytepp rows = png_get_rows(dp->read_pp, dp->read_ip);
+      unsigned int mask;  /* mask (if not zero) for the final byte */
+
+      if (bit_depth < 8)
+      {
+         /* Need the stray bits at the end, this depends only on the low bits
+          * of the image width; overflow does not matter.  If the width is an
+          * exact multiple of 8 bits this gives a mask of 0, not 0xff.
+          */
+         mask = 0xff & (0xff00 >> ((bit_depth * width) & 7));
+      }
+
+      else
+         mask = 0;
+
+      if (rows == NULL)
+         display_log(dp, LIBPNG_BUG, "png_get_rows returned NULL");
+
+      if ((applied_transforms & PNG_TRANSFORM_SHIFT) == 0 ||
+         (dp->active_transforms & PNG_TRANSFORM_SHIFT) == 0 ||
+         color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         unsigned long y;
+
+         for (y=0; y<height; ++y)
+         {
+            png_bytep row = rows[y];
+            png_bytep orig = dp->original_rows[y];
+
+            if (memcmp(row, orig, rowbytes-(mask != 0)) != 0 || (mask != 0 &&
+               ((row[rowbytes-1] & mask) != (orig[rowbytes-1] & mask))))
+            {
+               size_t x;
+
+               /* Find the first error */
+               for (x=0; x<rowbytes-1; ++x)
+                  if (row[x] != orig[x])
+                     break;
+
+               display_log(dp, APP_FAIL,
+                  "byte(%lu,%lu) changed 0x%.2x -> 0x%.2x",
+                  (unsigned long)x, (unsigned long)y, orig[x], row[x]);
+               return 0; /* don't keep reporting failed rows on 'continue' */
+            }
+         }
+      }
+
+      else
+#     ifdef PNG_sBIT_SUPPORTED
+      {
+         unsigned long y;
+         int bpp;   /* bits-per-pixel then bytes-per-pixel */
+         /* components are up to 8 bytes in size */
+         png_byte sig_bits[8];
+         png_color_8p sBIT;
+
+         if (png_get_sBIT(dp->read_pp, dp->read_ip, &sBIT) != PNG_INFO_sBIT)
+            display_log(dp, INTERNAL_ERROR,
+               "active shift transform but no sBIT in file");
+
+         switch (color_type)
+         {
+            case PNG_COLOR_TYPE_GRAY:
+               sig_bits[0] = sBIT->gray;
+               bpp = bit_depth;
+               break;
+
+            case PNG_COLOR_TYPE_GA:
+               sig_bits[0] = sBIT->gray;
+               sig_bits[1] = sBIT->alpha;
+               bpp = 2 * bit_depth;
+               break;
+
+            case PNG_COLOR_TYPE_RGB:
+               sig_bits[0] = sBIT->red;
+               sig_bits[1] = sBIT->green;
+               sig_bits[2] = sBIT->blue;
+               bpp = 3 * bit_depth;
+               break;
+
+            case PNG_COLOR_TYPE_RGBA:
+               sig_bits[0] = sBIT->red;
+               sig_bits[1] = sBIT->green;
+               sig_bits[2] = sBIT->blue;
+               sig_bits[3] = sBIT->alpha;
+               bpp = 4 * bit_depth;
+               break;
+
+            default:
+               display_log(dp, LIBPNG_ERROR, "invalid colour type %d",
+                  color_type);
+               /*NOTREACHED*/
+               memset(sig_bits, 0, sizeof(sig_bits));
+               bpp = 0;
+               break;
+         }
+
+         {
+            int b;
+
+            for (b=0; 8*b<bpp; ++b)
+            {
+               /* libpng should catch this; if not there is a security issue
+                * because an app (like this one) may overflow an array. In fact
+                * libpng doesn't catch this at present.
+                */
+               if (sig_bits[b] == 0 || sig_bits[b] > bit_depth/*!palette*/)
+                  display_log(dp, LIBPNG_BUG,
+                     "invalid sBIT[%u]  value %d returned for PNG bit depth %d",
+                     b, sig_bits[b], bit_depth);
+            }
+         }
+
+         if (bpp < 8 && bpp != bit_depth)
+         {
+            /* sanity check; this is a grayscale PNG; something is wrong in the
+             * code above.
+             */
+            display_log(dp, INTERNAL_ERROR, "invalid bpp %u for bit_depth %u",
+               bpp, bit_depth);
+         }
+
+         switch (bit_depth)
+         {
+            int b;
+
+            case 16: /* Two bytes per component, big-endian */
+               for (b = (bpp >> 4); b > 0; --b)
+               {
+                  unsigned int sig = (unsigned int)(0xffff0000 >> sig_bits[b]);
+
+                  sig_bits[2*b+1] = (png_byte)sig;
+                  sig_bits[2*b+0] = (png_byte)(sig >> 8); /* big-endian */
+               }
+               break;
+
+            case 8: /* One byte per component */
+               for (b=0; b*8 < bpp; ++b)
+                  sig_bits[b] = (png_byte)(0xff00 >> sig_bits[b]);
+               break;
+
+            case 1: /* allowed, but dumb */
+               /* Value is 1 */
+               sig_bits[0] = 0xff;
+               break;
+
+            case 2: /* Replicate 4 times */
+               /* Value is 1 or 2 */
+               b = 0x3 & ((0x3<<2) >> sig_bits[0]);
+               b |= b << 2;
+               b |= b << 4;
+               sig_bits[0] = (png_byte)b;
+               break;
+
+            case 4: /* Replicate twice */
+               /* Value is 1, 2, 3 or 4 */
+               b = 0xf & ((0xf << 4) >> sig_bits[0]);
+               b |= b << 4;
+               sig_bits[0] = (png_byte)b;
+               break;
+
+            default:
+               display_log(dp, LIBPNG_BUG, "invalid bit depth %d", bit_depth);
+               break;
+         }
+
+         /* Convert bpp to bytes; this gives '1' for low-bit depth grayscale,
+          * where there are multiple pixels per byte.
+          */
+         bpp = (bpp+7) >> 3;
+
+         /* The mask can be combined with sig_bits[0] */
+         if (mask != 0)
+         {
+            mask &= sig_bits[0];
+
+            if (bpp != 1 || mask == 0)
+               display_log(dp, INTERNAL_ERROR, "mask calculation error %u, %u",
+                  bpp, mask);
+         }
+
+         for (y=0; y<height; ++y)
+         {
+            png_bytep row = rows[y];
+            png_bytep orig = dp->original_rows[y];
+            unsigned long x;
+
+            for (x=0; x<(width-(mask!=0)); ++x)
+            {
+               int b;
+
+               for (b=0; b<bpp; ++b)
+               {
+                  if ((*row++ & sig_bits[b]) != (*orig++ & sig_bits[b]))
+                  {
+                     display_log(dp, APP_FAIL,
+                        "significant bits at (%lu[%u],%lu) changed %.2x->%.2x",
+                        x, b, y, orig[-1], row[-1]);
+                     return 0;
+                  }
+               }
+            }
+
+            if (mask != 0 && (*row & mask) != (*orig & mask))
+            {
+               display_log(dp, APP_FAIL,
+                  "significant bits at (%lu[end],%lu) changed", x, y);
+               return 0;
+            }
+         } /* for y */
+      }
+#     else /* !sBIT */
+         display_log(dp, INTERNAL_ERROR,
+               "active shift transform but no sBIT support");
+#     endif /* !sBIT */
+   }
+
+   return 1; /* compare succeeded */
+}
+
+#ifdef PNG_WRITE_PNG_SUPPORTED
+static void
+buffer_write(struct display *dp, struct buffer *buffer, png_bytep data,
+   size_t size)
+   /* Generic write function used both from the write callback provided to
+    * libpng and from the generic read code.
+    */
+{
+   /* Write the data into the buffer, adding buffers as required */
+   struct buffer_list *last = buffer->last;
+   size_t end_count = buffer->end_count;
+
+   while (size > 0)
+   {
+      size_t avail;
+
+      if (end_count >= sizeof last->buffer)
+      {
+         if (last->next == NULL)
+         {
+            last = buffer_extend(last);
+
+            if (last == NULL)
+               display_log(dp, APP_ERROR, "out of memory saving file");
+         }
+
+         else
+            last = last->next;
+
+         buffer->last = last; /* avoid the need to rewrite every time */
+         end_count = 0;
+      }
+
+      avail = (sizeof last->buffer) - end_count;
+      if (avail > size)
+         avail = size;
+
+      memcpy(last->buffer + end_count, data, avail);
+      end_count += avail;
+      size -= avail;
+      data += avail;
+   }
+
+   buffer->end_count = end_count;
+}
+
+static void PNGCBAPI
+write_function(png_structp pp, png_bytep data, size_t size)
+{
+   buffer_write(get_dp(pp), get_buffer(pp), data, size);
+}
+
+static void
+write_png(struct display *dp, png_infop ip, int transforms)
+{
+   display_clean_write(dp); /* safety */
+
+   buffer_start_write(&dp->written_file);
+   dp->operation = "write";
+   dp->transforms = transforms;
+
+   dp->write_pp = png_create_write_struct(PNG_LIBPNG_VER_STRING, dp,
+      display_error, display_warning);
+
+   if (dp->write_pp == NULL)
+      display_log(dp, APP_ERROR, "failed to create write png_struct");
+
+   png_set_write_fn(dp->write_pp, &dp->written_file, write_function,
+      NULL/*flush*/);
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      /* Remove the user limits, if any */
+      png_set_user_limits(dp->write_pp, 0x7fffffff, 0x7fffffff);
+#  endif
+
+   /* Certain transforms require the png_info to be zapped to allow the
+    * transform to work correctly.
+    */
+   if (transforms & (PNG_TRANSFORM_PACKING|
+                     PNG_TRANSFORM_STRIP_FILLER|
+                     PNG_TRANSFORM_STRIP_FILLER_BEFORE))
+   {
+      int ct = dp->color_type;
+
+      if (transforms & (PNG_TRANSFORM_STRIP_FILLER|
+                        PNG_TRANSFORM_STRIP_FILLER_BEFORE))
+         ct &= ~PNG_COLOR_MASK_ALPHA;
+
+      png_set_IHDR(dp->write_pp, ip, dp->width, dp->height, dp->bit_depth, ct,
+         dp->interlace_method, dp->compression_method, dp->filter_method);
+   }
+
+   png_write_png(dp->write_pp, ip, transforms, NULL/*params*/);
+
+   /* Clean it on the way out - if control returns to the caller then the
+    * written_file contains the required data.
+    */
+   display_clean_write(dp);
+}
+#endif /* WRITE_PNG */
+
+static int
+skip_transform(struct display *dp, int tr)
+   /* Helper to test for a bad combo and log it if it is skipped */
+{
+   if ((dp->options & SKIP_BUGS) != 0 && is_bad_combo(tr))
+   {
+      /* Log this to stdout if logging is on, otherwise just do an information
+       * display_log.
+       */
+      if ((dp->options & LOG_SKIPPED) != 0)
+      {
+         printf("SKIP: %s transforms ", dp->filename);
+
+         while (tr != 0)
+         {
+            int next = first_transform(tr);
+            tr &= ~next;
+
+            printf("%s", transform_name(next));
+            if (tr != 0)
+               putchar('+');
+         }
+
+         putchar('\n');
+      }
+
+      else
+         display_log(dp, INFORMATION, "%s: skipped known bad combo 0x%x",
+            dp->filename, tr);
+
+      return 1; /* skip */
+   }
+
+   return 0; /* don't skip */
+}
+
+static void
+test_one_file(struct display *dp, const char *filename)
+{
+   /* First cache the file and update the display original file
+    * information for the new file.
+    */
+   dp->operation = "cache file";
+   dp->transforms = 0;
+   display_cache_file(dp, filename);
+   update_display(dp);
+
+   /* First test: if there are options that should be ignored for this file
+    * verify that they really are ignored.
+    */
+   if (dp->ignored_transforms != 0)
+   {
+      read_png(dp, &dp->original_file, "ignored transforms",
+         dp->ignored_transforms);
+
+      /* The result should be identical to the original_rows */
+      if (!compare_read(dp, 0/*transforms applied*/))
+         return; /* no point testing more */
+   }
+
+#ifdef PNG_WRITE_PNG_SUPPORTED
+   /* Second test: write the original PNG data out to a new file (to test the
+    * write side) then read the result back in and make sure that it hasn't
+    * changed.
+    */
+   dp->operation = "write";
+   write_png(dp, dp->original_ip, 0/*transforms*/);
+   read_png(dp, &dp->written_file, NULL, 0/*transforms*/);
+   if (!compare_read(dp, 0/*transforms applied*/))
+      return;
+#endif
+
+   /* Third test: the active options.  Test each in turn, or, with the
+    * EXHAUSTIVE option, test all possible combinations.
+    */
+   {
+      /* Use unsigned int here because the code below to increment through all
+       * the possibilities exhaustively has to use a compare and that must be
+       * unsigned, because some transforms are negative on a 16-bit system.
+       */
+      unsigned int active = dp->active_transforms;
+      int exhaustive = (dp->options & EXHAUSTIVE) != 0;
+      unsigned int current = first_transform(active);
+      unsigned int bad_transforms = 0;
+      unsigned int bad_combo = ~0U;    /* bitwise AND of failing transforms */
+      unsigned int bad_combo_list = 0; /* bitwise OR of failures */
+
+      for (;;)
+      {
+         read_png(dp, &dp->original_file, "active transforms", current);
+
+         /* If this involved any irreversible transformations then if we write
+          * it out with just the reversible transformations and read it in again
+          * with the same transforms we should get the same thing.  At present
+          * this isn't done - it just seems like a waste of time and it would
+          * require two sets of read png_struct/png_info.
+          *
+          * If there were no irreversible transformations then if we write it
+          * out and read it back in again (without the reversible transforms)
+          * we should get back to the place where we started.
+          */
+#ifdef PNG_WRITE_PNG_SUPPORTED
+         if ((current & write_transforms) == current)
+         {
+            /* All transforms reversible: write the PNG with the transformations
+             * reversed, then read it back in with no transformations.  The
+             * result should be the same as the original apart from the loss of
+             * low order bits because of the SHIFT/sBIT transform.
+             */
+            dp->operation = "reversible transforms";
+            write_png(dp, dp->read_ip, current);
+
+            /* And if this is read back in, because all the transformations were
+             * reversible, the result should be the same.
+             */
+            read_png(dp, &dp->written_file, NULL, 0);
+            if (!compare_read(dp, current/*for the SHIFT/sBIT transform*/))
+            {
+               /* This set of transforms failed.  If a single bit is set - if
+                * there is just one transform - don't include this in further
+                * 'exhaustive' tests.  Notice that each transform is tested on
+                * its own before testing combos in the exhaustive case.
+                */
+               if (is_combo(current))
+               {
+                  bad_combo &= current;
+                  bad_combo_list |= current;
+               }
+
+               else
+                  bad_transforms |= current;
+            }
+         }
+#endif
+
+         /* Now move to the next transform */
+         if (exhaustive) /* all combinations */
+         {
+            unsigned int next = current;
+
+            do
+            {
+               if (next == read_transforms) /* Everything tested */
+                  goto combo;
+
+               ++next;
+            }  /* skip known bad combos if the relevant option is set; skip
+                * combos involving known bad single transforms in all cases.
+                */
+            while (  (next & read_transforms) <= current
+                  || (next & active) == 0 /* skip cases that do nothing */
+                  || (next & bad_transforms) != 0
+                  || skip_transform(dp, next));
+
+            assert((next & read_transforms) == next);
+            current = next;
+         }
+
+         else /* one at a time */
+         {
+            active &= ~current;
+
+            if (active == 0)
+               goto combo;
+
+            current = first_transform(active);
+         }
+      }
+
+combo:
+      if (dp->options & FIND_BAD_COMBOS)
+      {
+         /* bad_combos identifies the combos that occur in all failing cases;
+          * bad_combo_list identifies transforms that do not prevent the
+          * failure.
+          */
+         if (bad_combo != ~0U)
+            printf("%s[0x%x]: PROBLEM: 0x%x[0x%x] ANTIDOTE: 0x%x\n",
+               dp->filename, active, bad_combo, bad_combo_list,
+               rw_transforms & ~bad_combo_list);
+
+         else
+            printf("%s: no %sbad combos found\n", dp->filename,
+               (dp->options & SKIP_BUGS) ? "additional " : "");
+      }
+   }
+}
+
+static int
+do_test(struct display *dp, const char *file)
+   /* Exists solely to isolate the setjmp clobbers */
+{
+   int ret = setjmp(dp->error_return);
+
+   if (ret == 0)
+   {
+      test_one_file(dp, file);
+      return 0;
+   }
+
+   else if (ret < ERRORS) /* shouldn't longjmp on warnings */
+      display_log(dp, INTERNAL_ERROR, "unexpected return code %d", ret);
+
+   return ret;
+}
+
+int
+main(int argc, char **argv)
+{
+   /* For each file on the command line test it with a range of transforms */
+   int option_end, ilog = 0;
+   struct display d;
+
+   validate_T();
+   display_init(&d);
+
+   for (option_end=1; option_end<argc; ++option_end)
+   {
+      const char *name = argv[option_end];
+
+      if (strcmp(name, "--verbose") == 0)
+         d.options = (d.options & ~LEVEL_MASK) | VERBOSE;
+
+      else if (strcmp(name, "--warnings") == 0)
+         d.options = (d.options & ~LEVEL_MASK) | WARNINGS;
+
+      else if (strcmp(name, "--errors") == 0)
+         d.options = (d.options & ~LEVEL_MASK) | ERRORS;
+
+      else if (strcmp(name, "--quiet") == 0)
+         d.options = (d.options & ~LEVEL_MASK) | QUIET;
+
+      else if (strcmp(name, "--exhaustive") == 0)
+         d.options |= EXHAUSTIVE;
+
+      else if (strcmp(name, "--fast") == 0)
+         d.options &= ~EXHAUSTIVE;
+
+      else if (strcmp(name, "--strict") == 0)
+         d.options |= STRICT;
+
+      else if (strcmp(name, "--relaxed") == 0)
+         d.options &= ~STRICT;
+
+      else if (strcmp(name, "--log") == 0)
+      {
+         ilog = option_end; /* prevent display */
+         d.options |= LOG;
+      }
+
+      else if (strcmp(name, "--nolog") == 0)
+         d.options &= ~LOG;
+
+      else if (strcmp(name, "--continue") == 0)
+         d.options |= CONTINUE;
+
+      else if (strcmp(name, "--stop") == 0)
+         d.options &= ~CONTINUE;
+
+      else if (strcmp(name, "--skip-bugs") == 0)
+         d.options |= SKIP_BUGS;
+
+      else if (strcmp(name, "--test-all") == 0)
+         d.options &= ~SKIP_BUGS;
+
+      else if (strcmp(name, "--log-skipped") == 0)
+         d.options |= LOG_SKIPPED;
+
+      else if (strcmp(name, "--nolog-skipped") == 0)
+         d.options &= ~LOG_SKIPPED;
+
+      else if (strcmp(name, "--find-bad-combos") == 0)
+         d.options |= FIND_BAD_COMBOS;
+
+      else if (strcmp(name, "--nofind-bad-combos") == 0)
+         d.options &= ~FIND_BAD_COMBOS;
+
+      else if (strcmp(name, "--list-combos") == 0)
+         d.options |= LIST_COMBOS;
+
+      else if (strcmp(name, "--nolist-combos") == 0)
+         d.options &= ~LIST_COMBOS;
+
+      else if (name[0] == '-' && name[1] == '-')
+      {
+         fprintf(stderr, "pngimage: %s: unknown option\n", name);
+         return 99;
+      }
+
+      else
+         break; /* Not an option */
+   }
+
+   {
+      int i;
+      int errors = 0;
+
+      for (i=option_end; i<argc; ++i)
+      {
+         {
+            int ret = do_test(&d, argv[i]);
+
+            if (ret > QUIET) /* abort on user or internal error */
+               return 99;
+         }
+
+         /* Here on any return, including failures, except user/internal issues
+          */
+         {
+            int pass = (d.options & STRICT) ?
+               RESULT_STRICT(d.results) : RESULT_RELAXED(d.results);
+
+            if (!pass)
+               ++errors;
+
+            if (d.options & LOG)
+            {
+               int j;
+
+               printf("%s: pngimage ", pass ? "PASS" : "FAIL");
+
+               for (j=1; j<option_end; ++j)
+                  if (j != ilog)
+                     printf("%s ", argv[j]);
+
+               printf("%s\n", d.filename);
+            }
+         }
+
+         display_clean(&d);
+      }
+
+      /* Release allocated memory */
+      display_destroy(&d);
+
+      return errors != 0;
+   }
+}
+#else /* !READ_PNG */
+int
+main(void)
+{
+   fprintf(stderr, "pngimage: no support for png_read/write_image\n");
+   return SKIP;
+}
+#endif
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngstest-errors.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngstest-errors.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngstest-errors.h	(revision 107811)
@@ -0,0 +1,165 @@
+/* contrib/libtests/pngstest-errors.h
+ *
+ * BUILT USING: libpng version 1.6.19beta03 - September 25, 2015
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * THIS IS A MACHINE GENERATED FILE: do not edit it directly!
+ * Instead run:
+ *
+ *    pngstest --accumulate
+ *
+ * on as many PNG files as possible; at least PNGSuite and
+ * contrib/libtests/testpngs.
+ */
+static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =
+{
+ { /* input: sRGB-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: sRGB-gray+alpha */
+  { 0, 19, 0, 0 }, { 0, 0, 0, 0 }, { 0, 20, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: sRGB-rgb */
+  { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 893, 0 }, { 0, 0, 893, 0 }, { 0, 0, 811, 0 }, { 0, 0, 811, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: sRGB-rgb+alpha */
+  { 0, 16, 17, 0 }, { 0, 17, 17, 0 }, { 0, 19, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 850, 875, 0 }, { 0, 850, 875, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-gray */
+  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-gray+alpha */
+  { 0, 74, 9, 0 }, { 0, 20, 9, 0 }, { 0, 74, 9, 0 }, { 0, 20, 9, 0 },
+  { 0, 0, 0, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-rgb */
+  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 4, 0 }, { 0, 0, 4, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: linear-rgb+alpha */
+  { 0, 126, 143, 0 }, { 0, 11, 7, 0 }, { 0, 74, 9, 0 }, { 0, 17, 9, 0 },
+  { 0, 4, 4, 0 }, { 0, 5, 4, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-rgb */
+  { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 673, 0 }, { 0, 0, 673, 0 }, { 0, 0, 674, 0 }, { 0, 0, 674, 0 },
+  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 460, 0 }, { 0, 0, 460, 0 }, { 0, 0, 263, 0 }, { 0, 0, 263, 0 }
+ }, { /* input: color-mapped-sRGB-rgb+alpha */
+  { 0, 6, 8, 0 }, { 0, 7, 8, 0 }, { 0, 75, 9, 0 }, { 0, 9, 9, 0 },
+  { 0, 585, 427, 0 }, { 0, 585, 427, 0 }, { 0, 717, 514, 0 }, { 0, 717, 514, 0 },
+  { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 13323, 460, 0 }, { 0, 427, 460, 0 }, { 0, 16480, 263, 0 }, { 0, 243, 263, 0 }
+ }, { /* input: color-mapped-linear-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 253, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 265, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 },
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 243, 265, 0 }
+ }
+};
+static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =
+{
+ { /* input: sRGB-gray */
+  { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }
+ }, { /* input: sRGB-gray+alpha */
+  { 0, 15, 15, 0 }, { 0, 186, 15, 0 }, { 0, 15, 15, 0 }, { 0, 186, 15, 0 }
+ }, { /* input: sRGB-rgb */
+  { 0, 0, 20, 0 }, { 0, 0, 20, 0 }, { 0, 0, 15, 0 }, { 0, 0, 15, 0 }
+ }, { /* input: sRGB-rgb+alpha */
+  { 0, 16, 17, 0 }, { 0, 187, 17, 0 }, { 0, 15, 15, 0 }, { 0, 186, 15, 0 }
+ }, { /* input: linear-gray */
+  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
+ }, { /* input: linear-gray+alpha */
+  { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
+ }, { /* input: linear-rgb */
+  { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }
+ }, { /* input: linear-rgb+alpha */
+  { 0, 1, 1, 0 }, { 0, 9, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }
+ }, { /* input: color-mapped-sRGB-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-sRGB-rgb */
+  { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 14, 0 }, { 0, 0, 14, 0 }
+ }, { /* input: color-mapped-sRGB-rgb+alpha */
+  { 0, 4, 8, 0 }, { 0, 9, 8, 0 }, { 0, 9, 5, 0 }, { 0, 32, 5, 0 }
+ }, { /* input: color-mapped-linear-gray */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-gray+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }, { /* input: color-mapped-linear-rgb+alpha */
+  { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }
+ }
+};
+static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =
+{
+ { /* input: sRGB-gray */
+  { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 },
+  { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }
+ }, { /* input: sRGB-gray+alpha */
+  { 0, 19, 9, 0 }, { 0, 255, 9, 25 }, { 0, 88, 9, 0 }, { 0, 255, 9, 25 },
+  { 0, 1012, 928, 0 }, { 0, 16026, 928, 6425 }, { 0, 1012, 928, 0 }, { 0, 16026, 928, 6425 }
+ }, { /* input: sRGB-rgb */
+  { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 25, 0 }, { 0, 0, 25, 0 },
+  { 0, 0, 962, 0 }, { 0, 0, 962, 0 }, { 0, 0, 13677, 0 }, { 0, 0, 13677, 0 }
+ }, { /* input: sRGB-rgb+alpha */
+  { 0, 63, 77, 0 }, { 0, 255, 19, 25 }, { 0, 225, 25, 0 }, { 0, 255, 25, 67 },
+  { 0, 17534, 18491, 0 }, { 0, 15736, 2824, 6425 }, { 0, 14019, 13677, 0 }, { 0, 50115, 13677, 17219 }
+ }, { /* input: linear-gray */
+  { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 },
+  { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }
+ }, { /* input: linear-gray+alpha */
+  { 0, 74, 74, 0 }, { 0, 255, 74, 25 }, { 0, 99, 74, 0 }, { 0, 255, 74, 25 },
+  { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6553 }, { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6553 }
+ }, { /* input: linear-rgb */
+  { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 98, 0 }, { 0, 0, 98, 0 },
+  { 0, 0, 18664, 0 }, { 0, 0, 18664, 0 }, { 0, 0, 24998, 0 }, { 0, 0, 24998, 0 }
+ }, { /* input: linear-rgb+alpha */
+  { 0, 181, 196, 0 }, { 0, 255, 61, 25 }, { 206, 187, 98, 0 }, { 0, 255, 98, 67 },
+  { 0, 18141, 18137, 0 }, { 0, 17494, 17504, 6553 }, { 0, 24979, 24992, 0 }, { 0, 49172, 24992, 17347 }
+ }
+};
+/* END MACHINE GENERATED */
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngstest.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngstest.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngstest.c	(revision 107811)
@@ -0,0 +1,3832 @@
+
+/* pngstest.c
+ *
+ * Copyright (c) 2021 Cosmin Truta
+ * Copyright (c) 2013-2017 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Test for the PNG 'simplified' APIs.
+ */
+
+#define _ISOC90_SOURCE 1
+#define MALLOC_CHECK_ 2 /*glibc facility: turn on debugging*/
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <ctype.h>
+#include <math.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED /* Else nothing can be done */
+#include "../tools/sRGB.h"
+
+/* KNOWN ISSUES
+ *
+ * These defines switch on alternate algorithms for format conversions to match
+ * the current libpng implementation; they are set to allow pngstest to pass
+ * even though libpng is producing answers that are not as correct as they
+ * should be.
+ */
+#define ALLOW_UNUSED_GPC 0
+   /* If true include unused static GPC functions and declare an external array
+    * of them to hide the fact that they are unused.  This is for development
+    * use while testing the correct function to use to take into account libpng
+    * misbehavior, such as using a simple power law to correct sRGB to linear.
+    */
+
+/* The following is to support direct compilation of this file as C++ */
+#ifdef __cplusplus
+#  define voidcast(type, value) static_cast<type>(value)
+#  define aligncastconst(type, value) \
+      static_cast<type>(static_cast<const void*>(value))
+#else
+#  define voidcast(type, value) (value)
+#  define aligncastconst(type, value) ((const void*)(value))
+#endif /* __cplusplus */
+
+/* During parallel runs of pngstest each temporary file needs a unique name,
+ * this is used to permit uniqueness using a command line argument which can be
+ * up to 22 characters long.
+ */
+static char tmpf[23] = "TMP";
+
+/* Generate random bytes.  This uses a boring repeatable algorithm and it
+ * is implemented here so that it gives the same set of numbers on every
+ * architecture.  It's a linear congruential generator (Knuth or Sedgewick
+ * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
+ * Hill, "The Art of Electronics".
+ */
+static void
+make_random_bytes(png_uint_32* seed, void* pv, size_t size)
+{
+   png_uint_32 u0 = seed[0], u1 = seed[1];
+   png_bytep bytes = voidcast(png_bytep, pv);
+
+   /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
+    * bit-20.  The top 1 bit is in u1, the bottom 32 are in u0.
+    */
+   size_t i;
+   for (i=0; i<size; ++i)
+   {
+      /* First generate 8 new bits then shift them in at the end. */
+      png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
+      u1 <<= 8;
+      u1 |= u0 >> 24;
+      u0 <<= 8;
+      u0 |= u;
+      *bytes++ = (png_byte)u;
+   }
+
+   seed[0] = u0;
+   seed[1] = u1;
+}
+
+static png_uint_32 color_seed[2];
+
+static void
+reseed(void)
+{
+   color_seed[0] = 0x12345678U;
+   color_seed[1] = 0x9abcdefU;
+}
+
+static void
+random_color(png_colorp color)
+{
+   make_random_bytes(color_seed, color, sizeof *color);
+}
+
+/* Math support - neither Cygwin nor Visual Studio have C99 support and we need
+ * a predictable rounding function, so make one here:
+ */
+static double
+closestinteger(double x)
+{
+   return floor(x + .5);
+}
+
+/* Cast support: remove GCC whines. */
+static png_byte
+u8d(double d)
+{
+   d = closestinteger(d);
+   return (png_byte)d;
+}
+
+static png_uint_16
+u16d(double d)
+{
+   d = closestinteger(d);
+   return (png_uint_16)d;
+}
+
+/* sRGB support: use exact calculations rounded to the nearest int, see the
+ * fesetround() call in main().  sRGB_to_d optimizes the 8 to 16-bit conversion.
+ */
+static double sRGB_to_d[256];
+static double g22_to_d[256];
+
+static void
+init_sRGB_to_d(void)
+{
+   int i;
+
+   sRGB_to_d[0] = 0;
+   for (i=1; i<255; ++i)
+      sRGB_to_d[i] = linear_from_sRGB(i/255.);
+   sRGB_to_d[255] = 1;
+
+   g22_to_d[0] = 0;
+   for (i=1; i<255; ++i)
+      g22_to_d[i] = pow(i/255., 1/.45455);
+   g22_to_d[255] = 1;
+}
+
+static png_byte
+sRGB(double linear /*range 0.0 .. 1.0*/)
+{
+   return u8d(255 * sRGB_from_linear(linear));
+}
+
+static png_byte
+isRGB(int fixed_linear)
+{
+   return sRGB(fixed_linear / 65535.);
+}
+
+#if 0 /* not used */
+static png_byte
+unpremultiply(int component, int alpha)
+{
+   if (alpha <= component)
+      return 255; /* Arbitrary, but consistent with the libpng code */
+
+   else if (alpha >= 65535)
+      return isRGB(component);
+
+   else
+      return sRGB((double)component / alpha);
+}
+#endif
+
+static png_uint_16
+ilinear(int fixed_srgb)
+{
+   return u16d(65535 * sRGB_to_d[fixed_srgb]);
+}
+
+static png_uint_16
+ilineara(int fixed_srgb, int alpha)
+{
+   return u16d((257 * alpha) * sRGB_to_d[fixed_srgb]);
+}
+
+static png_uint_16
+ilinear_g22(int fixed_srgb)
+{
+   return u16d(65535 * g22_to_d[fixed_srgb]);
+}
+
+#if ALLOW_UNUSED_GPC
+static png_uint_16
+ilineara_g22(int fixed_srgb, int alpha)
+{
+   return u16d((257 * alpha) * g22_to_d[fixed_srgb]);
+}
+#endif
+
+static double
+YfromRGBint(int ir, int ig, int ib)
+{
+   double r = ir;
+   double g = ig;
+   double b = ib;
+   return YfromRGB(r, g, b);
+}
+
+#if 0 /* unused */
+/* The error that results from using a 2.2 power law in place of the correct
+ * sRGB transform, given an 8-bit value which might be either sRGB or power-law.
+ */
+static int
+power_law_error8(int value)
+{
+   if (value > 0 && value < 255)
+   {
+      double vd = value / 255.;
+      double e = fabs(
+         pow(sRGB_to_d[value], 1/2.2) - sRGB_from_linear(pow(vd, 2.2)));
+
+      /* Always allow an extra 1 here for rounding errors */
+      e = 1+floor(255 * e);
+      return (int)e;
+   }
+
+   return 0;
+}
+
+static int error_in_sRGB_roundtrip = 56; /* by experiment */
+static int
+power_law_error16(int value)
+{
+   if (value > 0 && value < 65535)
+   {
+      /* Round trip the value through an 8-bit representation but using
+       * non-matching to/from conversions.
+       */
+      double vd = value / 65535.;
+      double e = fabs(
+         pow(sRGB_from_linear(vd), 2.2) - linear_from_sRGB(pow(vd, 1/2.2)));
+
+      /* Always allow an extra 1 here for rounding errors */
+      e = error_in_sRGB_roundtrip+floor(65535 * e);
+      return (int)e;
+   }
+
+   return 0;
+}
+
+static int
+compare_8bit(int v1, int v2, int error_limit, int multiple_algorithms)
+{
+   int e = abs(v1-v2);
+   int ev1, ev2;
+
+   if (e <= error_limit)
+      return 1;
+
+   if (!multiple_algorithms)
+      return 0;
+
+   ev1 = power_law_error8(v1);
+   if (e <= ev1)
+      return 1;
+
+   ev2 = power_law_error8(v2);
+   if (e <= ev2)
+      return 1;
+
+   return 0;
+}
+
+static int
+compare_16bit(int v1, int v2, int error_limit, int multiple_algorithms)
+{
+   int e = abs(v1-v2);
+   int ev1, ev2;
+
+   if (e <= error_limit)
+      return 1;
+
+   /* "multiple_algorithms" in this case means that a color-map has been
+    * involved somewhere, so we can deduce that the values were forced to 8-bit
+    * (like the via_linear case for 8-bit.)
+    */
+   if (!multiple_algorithms)
+      return 0;
+
+   ev1 = power_law_error16(v1);
+   if (e <= ev1)
+      return 1;
+
+   ev2 = power_law_error16(v2);
+   if (e <= ev2)
+      return 1;
+
+   return 0;
+}
+#endif /* unused */
+
+#define USE_FILE 1       /* else memory */
+#define USE_STDIO 2      /* else use file name */
+#define STRICT 4         /* fail on warnings too */
+#define VERBOSE 8
+#define KEEP_TMPFILES 16 /* else delete temporary files */
+#define KEEP_GOING 32
+#define ACCUMULATE 64
+#define FAST_WRITE 128
+#define sRGB_16BIT 256
+#define NO_RESEED  512   /* do not reseed on each new file */
+#define GBG_ERROR 1024   /* do not ignore the gamma+background_rgb_to_gray
+                          * libpng warning. */
+
+static void
+print_opts(png_uint_32 opts)
+{
+   if (opts & USE_FILE)
+      printf(" --file");
+   if (opts & USE_STDIO)
+      printf(" --stdio");
+   if (!(opts & STRICT))
+      printf(" --nostrict");
+   if (opts & VERBOSE)
+      printf(" --verbose");
+   if (opts & KEEP_TMPFILES)
+      printf(" --preserve");
+   if (opts & KEEP_GOING)
+      printf(" --keep-going");
+   if (opts & ACCUMULATE)
+      printf(" --accumulate");
+   if (!(opts & FAST_WRITE)) /* --fast is currently the default */
+      printf(" --slow");
+   if (opts & sRGB_16BIT)
+      printf(" --sRGB-16bit");
+   if (opts & NO_RESEED)
+      printf(" --noreseed");
+#if PNG_LIBPNG_VER < 10700 /* else on by default */
+   if (opts & GBG_ERROR)
+      printf(" --fault-gbg-warning");
+#endif
+}
+
+#define FORMAT_NO_CHANGE 0x80000000 /* additional flag */
+
+/* A name table for all the formats - defines the format of the '+' arguments to
+ * pngstest.
+ */
+#define FORMAT_COUNT 64
+#define FORMAT_MASK 0x3f
+static const char * const format_names[FORMAT_COUNT] =
+{
+   "sRGB-gray",
+   "sRGB-gray+alpha",
+   "sRGB-rgb",
+   "sRGB-rgb+alpha",
+   "linear-gray",
+   "linear-gray+alpha",
+   "linear-rgb",
+   "linear-rgb+alpha",
+
+   "color-mapped-sRGB-gray",
+   "color-mapped-sRGB-gray+alpha",
+   "color-mapped-sRGB-rgb",
+   "color-mapped-sRGB-rgb+alpha",
+   "color-mapped-linear-gray",
+   "color-mapped-linear-gray+alpha",
+   "color-mapped-linear-rgb",
+   "color-mapped-linear-rgb+alpha",
+
+   "sRGB-gray",
+   "sRGB-gray+alpha",
+   "sRGB-bgr",
+   "sRGB-bgr+alpha",
+   "linear-gray",
+   "linear-gray+alpha",
+   "linear-bgr",
+   "linear-bgr+alpha",
+
+   "color-mapped-sRGB-gray",
+   "color-mapped-sRGB-gray+alpha",
+   "color-mapped-sRGB-bgr",
+   "color-mapped-sRGB-bgr+alpha",
+   "color-mapped-linear-gray",
+   "color-mapped-linear-gray+alpha",
+   "color-mapped-linear-bgr",
+   "color-mapped-linear-bgr+alpha",
+
+   "sRGB-gray",
+   "alpha+sRGB-gray",
+   "sRGB-rgb",
+   "alpha+sRGB-rgb",
+   "linear-gray",
+   "alpha+linear-gray",
+   "linear-rgb",
+   "alpha+linear-rgb",
+
+   "color-mapped-sRGB-gray",
+   "color-mapped-alpha+sRGB-gray",
+   "color-mapped-sRGB-rgb",
+   "color-mapped-alpha+sRGB-rgb",
+   "color-mapped-linear-gray",
+   "color-mapped-alpha+linear-gray",
+   "color-mapped-linear-rgb",
+   "color-mapped-alpha+linear-rgb",
+
+   "sRGB-gray",
+   "alpha+sRGB-gray",
+   "sRGB-bgr",
+   "alpha+sRGB-bgr",
+   "linear-gray",
+   "alpha+linear-gray",
+   "linear-bgr",
+   "alpha+linear-bgr",
+
+   "color-mapped-sRGB-gray",
+   "color-mapped-alpha+sRGB-gray",
+   "color-mapped-sRGB-bgr",
+   "color-mapped-alpha+sRGB-bgr",
+   "color-mapped-linear-gray",
+   "color-mapped-alpha+linear-gray",
+   "color-mapped-linear-bgr",
+   "color-mapped-alpha+linear-bgr",
+};
+
+/* Decode an argument to a format number. */
+static png_uint_32
+formatof(const char *arg)
+{
+   char *ep;
+   unsigned long format = strtoul(arg, &ep, 0);
+
+   if (ep > arg && *ep == 0 && format < FORMAT_COUNT)
+      return (png_uint_32)format;
+
+   else for (format=0; format < FORMAT_COUNT; ++format)
+   {
+      if (strcmp(format_names[format], arg) == 0)
+         return (png_uint_32)format;
+   }
+
+   fprintf(stderr, "pngstest: format name '%s' invalid\n", arg);
+   return FORMAT_COUNT;
+}
+
+/* Bitset/test functions for formats */
+#define FORMAT_SET_COUNT (FORMAT_COUNT / 32)
+typedef struct
+{
+   png_uint_32 bits[FORMAT_SET_COUNT];
+}
+format_list;
+
+static void format_init(format_list *pf)
+{
+   int i;
+   for (i=0; i<FORMAT_SET_COUNT; ++i)
+      pf->bits[i] = 0; /* All off */
+}
+
+#if 0 /* currently unused */
+static void format_clear(format_list *pf)
+{
+   int i;
+   for (i=0; i<FORMAT_SET_COUNT; ++i)
+      pf->bits[i] = 0;
+}
+#endif
+
+static int format_is_initial(format_list *pf)
+{
+   int i;
+   for (i=0; i<FORMAT_SET_COUNT; ++i)
+      if (pf->bits[i] != 0)
+         return 0;
+
+   return 1;
+}
+
+static int format_set(format_list *pf, png_uint_32 format)
+{
+   if (format < FORMAT_COUNT)
+      return pf->bits[format >> 5] |= ((png_uint_32)1) << (format & 31);
+
+   return 0;
+}
+
+#if 0 /* currently unused */
+static int format_unset(format_list *pf, png_uint_32 format)
+{
+   if (format < FORMAT_COUNT)
+      return pf->bits[format >> 5] &= ~((png_uint_32)1) << (format & 31);
+
+   return 0;
+}
+#endif
+
+static int format_isset(format_list *pf, png_uint_32 format)
+{
+   return format < FORMAT_COUNT &&
+      (pf->bits[format >> 5] & (((png_uint_32)1) << (format & 31))) != 0;
+}
+
+static void format_default(format_list *pf, int redundant)
+{
+   if (redundant)
+   {
+      int i;
+
+      /* set everything, including flags that are pointless */
+      for (i=0; i<FORMAT_SET_COUNT; ++i)
+         pf->bits[i] = ~(png_uint_32)0;
+   }
+
+   else
+   {
+      png_uint_32 f;
+
+      for (f=0; f<FORMAT_COUNT; ++f)
+      {
+         /* Eliminate redundant and unsupported settings. */
+#        ifdef PNG_FORMAT_BGR_SUPPORTED
+            /* BGR is meaningless if no color: */
+            if ((f & PNG_FORMAT_FLAG_COLOR) == 0 &&
+               (f & PNG_FORMAT_FLAG_BGR) != 0)
+#        else
+            if ((f & 0x10U/*HACK: fixed value*/) != 0)
+#        endif
+            continue;
+
+         /* AFIRST is meaningless if no alpha: */
+#        ifdef PNG_FORMAT_AFIRST_SUPPORTED
+            if ((f & PNG_FORMAT_FLAG_ALPHA) == 0 &&
+               (f & PNG_FORMAT_FLAG_AFIRST) != 0)
+#        else
+            if ((f & 0x20U/*HACK: fixed value*/) != 0)
+#        endif
+            continue;
+
+         format_set(pf, f);
+      }
+   }
+}
+
+/* THE Image STRUCTURE */
+/* The super-class of a png_image, contains the decoded image plus the input
+ * data necessary to re-read the file with a different format.
+ */
+typedef struct
+{
+   png_image   image;
+   png_uint_32 opts;
+   const char *file_name;
+   int         stride_extra;
+   FILE       *input_file;
+   png_voidp   input_memory;
+   size_t      input_memory_size;
+   png_bytep   buffer;
+   ptrdiff_t   stride;
+   size_t      bufsize;
+   size_t      allocsize;
+   char        tmpfile_name[32];
+   png_uint_16 colormap[256*4];
+}
+Image;
+
+/* Initializer: also sets the permitted error limit for 16-bit operations. */
+static void
+newimage(Image *image)
+{
+   memset(image, 0, sizeof *image);
+}
+
+/* Reset the image to be read again - only needs to rewind the FILE* at present.
+ */
+static void
+resetimage(Image *image)
+{
+   if (image->input_file != NULL)
+      rewind(image->input_file);
+}
+
+/* Free the image buffer; the buffer is re-used on a re-read, this is just for
+ * cleanup.
+ */
+static void
+freebuffer(Image *image)
+{
+   if (image->buffer) free(image->buffer);
+   image->buffer = NULL;
+   image->bufsize = 0;
+   image->allocsize = 0;
+}
+
+/* Delete function; cleans out all the allocated data and the temporary file in
+ * the image.
+ */
+static void
+freeimage(Image *image)
+{
+   freebuffer(image);
+   png_image_free(&image->image);
+
+   if (image->input_file != NULL)
+   {
+      fclose(image->input_file);
+      image->input_file = NULL;
+   }
+
+   if (image->input_memory != NULL)
+   {
+      free(image->input_memory);
+      image->input_memory = NULL;
+      image->input_memory_size = 0;
+   }
+
+   if (image->tmpfile_name[0] != 0 && (image->opts & KEEP_TMPFILES) == 0)
+   {
+      (void)remove(image->tmpfile_name);
+      image->tmpfile_name[0] = 0;
+   }
+}
+
+/* This is actually a re-initializer; allows an image structure to be re-used by
+ * freeing everything that relates to an old image.
+ */
+static void initimage(Image *image, png_uint_32 opts, const char *file_name,
+   int stride_extra)
+{
+   freeimage(image);
+   memset(&image->image, 0, sizeof image->image);
+   image->opts = opts;
+   image->file_name = file_name;
+   image->stride_extra = stride_extra;
+}
+
+/* Make sure the image buffer is big enough; allows re-use of the buffer if the
+ * image is re-read.
+ */
+#define BUFFER_INIT8 73
+static void
+allocbuffer(Image *image)
+{
+   size_t size = PNG_IMAGE_BUFFER_SIZE(image->image, image->stride);
+
+   if (size+32 > image->bufsize)
+   {
+      freebuffer(image);
+      image->buffer = voidcast(png_bytep, malloc(size+32));
+      if (image->buffer == NULL)
+      {
+         fflush(stdout);
+         fprintf(stderr,
+            "simpletest: out of memory allocating %lu(+32) byte buffer\n",
+            (unsigned long)size);
+         exit(1);
+      }
+      image->bufsize = size+32;
+   }
+
+   memset(image->buffer, 95, image->bufsize);
+   memset(image->buffer+16, BUFFER_INIT8, size);
+   image->allocsize = size;
+}
+
+/* Make sure 16 bytes match the given byte. */
+static int
+check16(png_const_bytep bp, int b)
+{
+   int i = 16;
+
+   do
+      if (*bp != b) return 1;
+   while (--i);
+
+   return 0;
+}
+
+/* Check for overwrite in the image buffer. */
+static void
+checkbuffer(Image *image, const char *arg)
+{
+   if (check16(image->buffer, 95))
+   {
+      fflush(stdout);
+      fprintf(stderr, "%s: overwrite at start of image buffer\n", arg);
+      exit(1);
+   }
+
+   if (check16(image->buffer+16+image->allocsize, 95))
+   {
+      fflush(stdout);
+      fprintf(stderr, "%s: overwrite at end of image buffer\n", arg);
+      exit(1);
+   }
+}
+
+/* ERROR HANDLING */
+/* Log a terminal error, also frees the libpng part of the image if necessary.
+ */
+static int
+logerror(Image *image, const char *a1, const char *a2, const char *a3)
+{
+   fflush(stdout);
+   if (image->image.warning_or_error)
+      fprintf(stderr, "%s%s%s: %s\n", a1, a2, a3, image->image.message);
+
+   else
+      fprintf(stderr, "%s%s%s\n", a1, a2, a3);
+
+   if (image->image.opaque != NULL)
+   {
+      fprintf(stderr, "%s: image opaque pointer non-NULL on error\n",
+         image->file_name);
+      png_image_free(&image->image);
+   }
+
+   return 0;
+}
+
+/* Log an error and close a file (just a utility to do both things in one
+ * function call.)
+ */
+static int
+logclose(Image *image, FILE *f, const char *name, const char *operation)
+{
+   int e = errno;
+
+   fclose(f);
+   return logerror(image, name, operation, strerror(e));
+}
+
+/* Make sure the png_image has been freed - validates that libpng is doing what
+ * the spec says and freeing the image.
+ */
+static int
+checkopaque(Image *image)
+{
+   if (image->image.opaque != NULL)
+   {
+      png_image_free(&image->image);
+      return logerror(image, image->file_name, ": opaque not NULL", "");
+   }
+
+   /* Separate out the gamma+background_rgb_to_gray warning because it may
+    * produce opaque component errors:
+    */
+   else if (image->image.warning_or_error != 0 &&
+            (strcmp(image->image.message,
+               "libpng does not support gamma+background+rgb_to_gray") == 0 ?
+                  (image->opts & GBG_ERROR) != 0 : (image->opts & STRICT) != 0))
+      return logerror(image, image->file_name, (image->opts & GBG_ERROR) != 0 ?
+                      " --fault-gbg-warning" : " --strict", "");
+
+   else
+      return 1;
+}
+
+/* IMAGE COMPARISON/CHECKING */
+/* Compare the pixels of two images, which should be the same but aren't.  The
+ * images must have been checked for a size match.
+ */
+typedef struct
+{
+   /* The components, for grayscale images the gray value is in 'g' and if alpha
+    * is not present 'a' is set to 255 or 65535 according to format.
+    */
+   int         r, g, b, a;
+} Pixel;
+
+typedef struct
+{
+   /* The background as the original sRGB 8-bit value converted to the final
+    * integer format and as a double precision linear value in the range 0..1
+    * for with partially transparent pixels.
+    */
+   int ir, ig, ib;
+   double dr, dg, db; /* linear r,g,b scaled to 0..1 */
+} Background;
+
+/* Basic image formats; control the data but not the layout thereof. */
+#define BASE_FORMATS\
+   (PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_LINEAR)
+
+/* Read a Pixel from a buffer.  The code below stores the correct routine for
+ * the format in a function pointer, these are the routines:
+ */
+static void
+gp_g8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = p->g = p->b = pp[0];
+   p->a = 255;
+}
+
+static void
+gp_ga8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = p->g = p->b = pp[0];
+   p->a = pp[1];
+}
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+static void
+gp_ag8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = p->g = p->b = pp[1];
+   p->a = pp[0];
+}
+#endif
+
+static void
+gp_rgb8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[0];
+   p->g = pp[1];
+   p->b = pp[2];
+   p->a = 255;
+}
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+static void
+gp_bgr8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[2];
+   p->g = pp[1];
+   p->b = pp[0];
+   p->a = 255;
+}
+#endif
+
+static void
+gp_rgba8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[0];
+   p->g = pp[1];
+   p->b = pp[2];
+   p->a = pp[3];
+}
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+static void
+gp_bgra8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[2];
+   p->g = pp[1];
+   p->b = pp[0];
+   p->a = pp[3];
+}
+#endif
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+static void
+gp_argb8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[1];
+   p->g = pp[2];
+   p->b = pp[3];
+   p->a = pp[0];
+}
+#endif
+
+#if defined(PNG_FORMAT_AFIRST_SUPPORTED) && defined(PNG_FORMAT_BGR_SUPPORTED)
+static void
+gp_abgr8(Pixel *p, png_const_voidp pb)
+{
+   png_const_bytep pp = voidcast(png_const_bytep, pb);
+
+   p->r = pp[3];
+   p->g = pp[2];
+   p->b = pp[1];
+   p->a = pp[0];
+}
+#endif
+
+static void
+gp_g16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = p->g = p->b = pp[0];
+   p->a = 65535;
+}
+
+static void
+gp_ga16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = p->g = p->b = pp[0];
+   p->a = pp[1];
+}
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+static void
+gp_ag16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = p->g = p->b = pp[1];
+   p->a = pp[0];
+}
+#endif
+
+static void
+gp_rgb16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[0];
+   p->g = pp[1];
+   p->b = pp[2];
+   p->a = 65535;
+}
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+static void
+gp_bgr16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[2];
+   p->g = pp[1];
+   p->b = pp[0];
+   p->a = 65535;
+}
+#endif
+
+static void
+gp_rgba16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[0];
+   p->g = pp[1];
+   p->b = pp[2];
+   p->a = pp[3];
+}
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+static void
+gp_bgra16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[2];
+   p->g = pp[1];
+   p->b = pp[0];
+   p->a = pp[3];
+}
+#endif
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+static void
+gp_argb16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[1];
+   p->g = pp[2];
+   p->b = pp[3];
+   p->a = pp[0];
+}
+#endif
+
+#if defined(PNG_FORMAT_AFIRST_SUPPORTED) && defined(PNG_FORMAT_BGR_SUPPORTED)
+static void
+gp_abgr16(Pixel *p, png_const_voidp pb)
+{
+   png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
+
+   p->r = pp[3];
+   p->g = pp[2];
+   p->b = pp[1];
+   p->a = pp[0];
+}
+#endif
+
+/* Given a format, return the correct one of the above functions. */
+static void (*
+get_pixel(png_uint_32 format))(Pixel *p, png_const_voidp pb)
+{
+   /* The color-map flag is irrelevant here - the caller of the function
+    * returned must either pass the buffer or, for a color-mapped image, the
+    * correct entry in the color-map.
+    */
+   if (format & PNG_FORMAT_FLAG_LINEAR)
+   {
+      if (format & PNG_FORMAT_FLAG_COLOR)
+      {
+#        ifdef PNG_FORMAT_BGR_SUPPORTED
+            if (format & PNG_FORMAT_FLAG_BGR)
+            {
+               if (format & PNG_FORMAT_FLAG_ALPHA)
+               {
+#                 ifdef PNG_FORMAT_AFIRST_SUPPORTED
+                     if (format & PNG_FORMAT_FLAG_AFIRST)
+                        return gp_abgr16;
+
+                     else
+#                 endif
+                     return gp_bgra16;
+               }
+
+               else
+                  return gp_bgr16;
+            }
+
+            else
+#        endif
+         {
+            if (format & PNG_FORMAT_FLAG_ALPHA)
+            {
+#              ifdef PNG_FORMAT_AFIRST_SUPPORTED
+                  if (format & PNG_FORMAT_FLAG_AFIRST)
+                     return gp_argb16;
+
+                  else
+#              endif
+                  return gp_rgba16;
+            }
+
+            else
+               return gp_rgb16;
+         }
+      }
+
+      else
+      {
+         if (format & PNG_FORMAT_FLAG_ALPHA)
+         {
+#           ifdef PNG_FORMAT_AFIRST_SUPPORTED
+               if (format & PNG_FORMAT_FLAG_AFIRST)
+                  return gp_ag16;
+
+               else
+#           endif
+               return gp_ga16;
+         }
+
+         else
+            return gp_g16;
+      }
+   }
+
+   else
+   {
+      if (format & PNG_FORMAT_FLAG_COLOR)
+      {
+#        ifdef PNG_FORMAT_BGR_SUPPORTED
+            if (format & PNG_FORMAT_FLAG_BGR)
+            {
+               if (format & PNG_FORMAT_FLAG_ALPHA)
+               {
+#                 ifdef PNG_FORMAT_AFIRST_SUPPORTED
+                     if (format & PNG_FORMAT_FLAG_AFIRST)
+                        return gp_abgr8;
+
+                     else
+#                 endif
+                     return gp_bgra8;
+               }
+
+               else
+                  return gp_bgr8;
+            }
+
+            else
+#        endif
+         {
+            if (format & PNG_FORMAT_FLAG_ALPHA)
+            {
+#              ifdef PNG_FORMAT_AFIRST_SUPPORTED
+                  if (format & PNG_FORMAT_FLAG_AFIRST)
+                     return gp_argb8;
+
+                  else
+#              endif
+                  return gp_rgba8;
+            }
+
+            else
+               return gp_rgb8;
+         }
+      }
+
+      else
+      {
+         if (format & PNG_FORMAT_FLAG_ALPHA)
+         {
+#           ifdef PNG_FORMAT_AFIRST_SUPPORTED
+               if (format & PNG_FORMAT_FLAG_AFIRST)
+                  return gp_ag8;
+
+               else
+#           endif
+               return gp_ga8;
+         }
+
+         else
+            return gp_g8;
+      }
+   }
+}
+
+/* Conversion between pixel formats.  The code above effectively eliminates the
+ * component ordering changes leaving three basic changes:
+ *
+ * 1) Remove an alpha channel by pre-multiplication or compositing on a
+ *    background color.  (Adding an alpha channel is a no-op.)
+ *
+ * 2) Remove color by mapping to grayscale.  (Grayscale to color is a no-op.)
+ *
+ * 3) Convert between 8-bit and 16-bit components.  (Both directions are
+ *    relevant.)
+ *
+ * This gives the following base format conversion matrix:
+ *
+ *   OUT:    ----- 8-bit -----    ----- 16-bit -----
+ *   IN     G    GA   RGB  RGBA  G    GA   RGB  RGBA
+ *  8 G     .    .    .    .     lin  lin  lin  lin
+ *  8 GA    bckg .    bckc .     pre' pre  pre' pre
+ *  8 RGB   g8   g8   .    .     glin glin lin  lin
+ *  8 RGBA  g8b  g8   bckc .     gpr' gpre pre' pre
+ * 16 G     sRGB sRGB sRGB sRGB  .    .    .    .
+ * 16 GA    b16g unpg b16c unpc  A    .    A    .
+ * 16 RGB   sG   sG   sRGB sRGB  g16  g16  .    .
+ * 16 RGBA  gb16 sGp  cb16 sCp   g16  g16' A    .
+ *
+ *  8-bit to 8-bit:
+ * bckg: composite on gray background
+ * bckc: composite on color background
+ * g8:   convert sRGB components to sRGB grayscale
+ * g8b:  convert sRGB components to grayscale and composite on gray background
+ *
+ *  8-bit to 16-bit:
+ * lin:  make sRGB components linear, alpha := 65535
+ * pre:  make sRGB components linear and premultiply by alpha  (scale alpha)
+ * pre': as 'pre' but alpha := 65535
+ * glin: make sRGB components linear, convert to grayscale, alpha := 65535
+ * gpre: make sRGB components grayscale and linear and premultiply by alpha
+ * gpr': as 'gpre' but alpha := 65535
+ *
+ *  16-bit to 8-bit:
+ * sRGB: convert linear components to sRGB, alpha := 255
+ * unpg: unpremultiply gray component and convert to sRGB (scale alpha)
+ * unpc: unpremultiply color components and convert to sRGB (scale alpha)
+ * b16g: composite linear onto gray background and convert the result to sRGB
+ * b16c: composite linear onto color background and convert the result to sRGB
+ * sG:   convert linear RGB to sRGB grayscale
+ * sGp:  unpremultiply RGB then convert to sRGB grayscale
+ * sCp:  unpremultiply RGB then convert to sRGB
+ * gb16: composite linear onto background and convert to sRGB grayscale
+ *       (order doesn't matter, the composite and grayscale operations permute)
+ * cb16: composite linear onto background and convert to sRGB
+ *
+ *  16-bit to 16-bit:
+ * A:    set alpha to 65535
+ * g16:  convert linear RGB to linear grayscale (alpha := 65535)
+ * g16': as 'g16' but alpha is unchanged
+ */
+/* Simple copy: */
+static void
+gpc_noop(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   out->r = in->r;
+   out->g = in->g;
+   out->b = in->b;
+   out->a = in->a;
+}
+
+#if ALLOW_UNUSED_GPC
+static void
+gpc_nop8(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   if (in->a == 0)
+      out->r = out->g = out->b = 255;
+
+   else
+   {
+      out->r = in->r;
+      out->g = in->g;
+      out->b = in->b;
+   }
+
+   out->a = in->a;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+static void
+gpc_nop6(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   if (in->a == 0)
+      out->r = out->g = out->b = 65535;
+
+   else
+   {
+      out->r = in->r;
+      out->g = in->g;
+      out->b = in->b;
+   }
+
+   out->a = in->a;
+}
+#endif
+
+/* 8-bit to 8-bit conversions */
+/* bckg: composite on gray background */
+static void
+gpc_bckg(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+      out->r = out->g = out->b = back->ig;
+
+   else if (in->a >= 255)
+      out->r = out->g = out->b = in->g;
+
+   else
+   {
+      double a = in->a / 255.;
+
+      out->r = out->g = out->b = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a));
+   }
+
+   out->a = 255;
+}
+
+/* bckc: composite on color background */
+static void
+gpc_bckc(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+   {
+      out->r = back->ir;
+      out->g = back->ig;
+      out->b = back->ib;
+   }
+
+   else if (in->a >= 255)
+   {
+      out->r = in->r;
+      out->g = in->g;
+      out->b = in->b;
+   }
+
+   else
+   {
+      double a = in->a / 255.;
+
+      out->r = sRGB(sRGB_to_d[in->r] * a + back->dr * (1-a));
+      out->g = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a));
+      out->b = sRGB(sRGB_to_d[in->b] * a + back->db * (1-a));
+   }
+
+   out->a = 255;
+}
+
+/* g8: convert sRGB components to sRGB grayscale */
+static void
+gpc_g8(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = in->g;
+
+   else
+      out->r = out->g = out->b =
+         sRGB(YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+
+   out->a = in->a;
+}
+
+/* g8b: convert sRGB components to grayscale and composite on gray background */
+static void
+gpc_g8b(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+      out->r = out->g = out->b = back->ig;
+
+   else if (in->a >= 255)
+   {
+      if (in->r == in->g && in->g == in->b)
+         out->r = out->g = out->b = in->g;
+
+      else
+         out->r = out->g = out->b = sRGB(YfromRGB(
+            sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+   }
+
+   else
+   {
+      double a = in->a/255.;
+
+      out->r = out->g = out->b = sRGB(a * YfromRGB(sRGB_to_d[in->r],
+         sRGB_to_d[in->g], sRGB_to_d[in->b]) + back->dg * (1-a));
+   }
+
+   out->a = 255;
+}
+
+/* 8-bit to 16-bit conversions */
+/* lin: make sRGB components linear, alpha := 65535 */
+static void
+gpc_lin(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilinear(in->r);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilinear(in->b);
+   }
+
+   else
+   {
+      out->g = ilinear(in->g);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilinear(in->b);
+   }
+
+   out->a = 65535;
+}
+
+/* pre: make sRGB components linear and premultiply by alpha (scale alpha) */
+static void
+gpc_pre(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilineara(in->r, in->a);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilineara(in->b, in->a);
+   }
+
+   else
+   {
+      out->g = ilineara(in->g, in->a);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilineara(in->b, in->a);
+   }
+
+   out->a = in->a * 257;
+}
+
+/* pre': as 'pre' but alpha := 65535 */
+static void
+gpc_preq(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilineara(in->r, in->a);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilineara(in->b, in->a);
+   }
+
+   else
+   {
+      out->g = ilineara(in->g, in->a);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilineara(in->b, in->a);
+   }
+
+   out->a = 65535;
+}
+
+/* glin: make sRGB components linear, convert to grayscale, alpha := 65535 */
+static void
+gpc_glin(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilinear(in->g);
+
+   else
+      out->r = out->g = out->b = u16d(65535 *
+         YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+
+   out->a = 65535;
+}
+
+/* gpre: make sRGB components grayscale and linear and premultiply by alpha */
+static void
+gpc_gpre(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilineara(in->g, in->a);
+
+   else
+      out->r = out->g = out->b = u16d(in->a * 257 *
+         YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+
+   out->a = 257 * in->a;
+}
+
+/* gpr': as 'gpre' but alpha := 65535 */
+static void
+gpc_gprq(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilineara(in->g, in->a);
+
+   else
+      out->r = out->g = out->b = u16d(in->a * 257 *
+         YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
+
+   out->a = 65535;
+}
+
+/* 8-bit to 16-bit conversions for gAMA 45455 encoded values */
+/* Lin: make gAMA 45455 components linear, alpha := 65535 */
+static void
+gpc_Lin(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilinear_g22(in->r);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilinear_g22(in->b);
+   }
+
+   else
+   {
+      out->g = ilinear_g22(in->g);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilinear_g22(in->b);
+   }
+
+   out->a = 65535;
+}
+
+#if ALLOW_UNUSED_GPC
+/* Pre: make gAMA 45455 components linear and premultiply by alpha (scale alpha)
+ */
+static void
+gpc_Pre(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilineara_g22(in->r, in->a);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilineara_g22(in->b, in->a);
+   }
+
+   else
+   {
+      out->g = ilineara_g22(in->g, in->a);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilineara_g22(in->b, in->a);
+   }
+
+   out->a = in->a * 257;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+/* Pre': as 'Pre' but alpha := 65535 */
+static void
+gpc_Preq(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = ilineara_g22(in->r, in->a);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = ilineara_g22(in->b, in->a);
+   }
+
+   else
+   {
+      out->g = ilineara_g22(in->g, in->a);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = ilineara_g22(in->b, in->a);
+   }
+
+   out->a = 65535;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+/* Glin: make gAMA 45455 components linear, convert to grayscale, alpha := 65535
+ */
+static void
+gpc_Glin(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilinear_g22(in->g);
+
+   else
+      out->r = out->g = out->b = u16d(65535 *
+         YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
+
+   out->a = 65535;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+/* Gpre: make gAMA 45455 components grayscale and linear and premultiply by
+ * alpha.
+ */
+static void
+gpc_Gpre(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilineara_g22(in->g, in->a);
+
+   else
+      out->r = out->g = out->b = u16d(in->a * 257 *
+         YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
+
+   out->a = 257 * in->a;
+}
+#endif
+
+#if ALLOW_UNUSED_GPC
+/* Gpr': as 'Gpre' but alpha := 65535 */
+static void
+gpc_Gprq(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->r == in->g && in->g == in->b)
+      out->r = out->g = out->b = ilineara_g22(in->g, in->a);
+
+   else
+      out->r = out->g = out->b = u16d(in->a * 257 *
+         YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
+
+   out->a = 65535;
+}
+#endif
+
+/* 16-bit to 8-bit conversions */
+/* sRGB: convert linear components to sRGB, alpha := 255 */
+static void
+gpc_sRGB(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = isRGB(in->r);
+
+   if (in->g == in->r)
+   {
+      out->g = out->r;
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else
+         out->b = isRGB(in->b);
+   }
+
+   else
+   {
+      out->g = isRGB(in->g);
+
+      if (in->b == in->r)
+         out->b = out->r;
+
+      else if (in->b == in->g)
+         out->b = out->g;
+
+      else
+         out->b = isRGB(in->b);
+   }
+
+   out->a = 255;
+}
+
+/* unpg: unpremultiply gray component and convert to sRGB (scale alpha) */
+static void
+gpc_unpg(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->a <= 128)
+   {
+      out->r = out->g = out->b = 255;
+      out->a = 0;
+   }
+
+   else
+   {
+      out->r = out->g = out->b = sRGB((double)in->g / in->a);
+      out->a = u8d(in->a / 257.);
+   }
+}
+
+/* unpc: unpremultiply color components and convert to sRGB (scale alpha) */
+static void
+gpc_unpc(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->a <= 128)
+   {
+      out->r = out->g = out->b = 255;
+      out->a = 0;
+   }
+
+   else
+   {
+      out->r = sRGB((double)in->r / in->a);
+      out->g = sRGB((double)in->g / in->a);
+      out->b = sRGB((double)in->b / in->a);
+      out->a = u8d(in->a / 257.);
+   }
+}
+
+/* b16g: composite linear onto gray background and convert the result to sRGB */
+static void
+gpc_b16g(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+      out->r = out->g = out->b = back->ig;
+
+   else
+   {
+      double a = in->a/65535.;
+      double a1 = 1-a;
+
+      a /= 65535;
+      out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1);
+   }
+
+   out->a = 255;
+}
+
+/* b16c: composite linear onto color background and convert the result to sRGB*/
+static void
+gpc_b16c(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+   {
+      out->r = back->ir;
+      out->g = back->ig;
+      out->b = back->ib;
+   }
+
+   else
+   {
+      double a = in->a/65535.;
+      double a1 = 1-a;
+
+      a /= 65535;
+      out->r = sRGB(in->r * a + back->dr * a1);
+      out->g = sRGB(in->g * a + back->dg * a1);
+      out->b = sRGB(in->b * a + back->db * a1);
+   }
+
+   out->a = 255;
+}
+
+/* sG: convert linear RGB to sRGB grayscale */
+static void
+gpc_sG(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/65535);
+   out->a = 255;
+}
+
+/* sGp: unpremultiply RGB then convert to sRGB grayscale */
+static void
+gpc_sGp(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->a <= 128)
+   {
+      out->r = out->g = out->b = 255;
+      out->a = 0;
+   }
+
+   else
+   {
+      out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/in->a);
+      out->a = u8d(in->a / 257.);
+   }
+}
+
+/* sCp: unpremultiply RGB then convert to sRGB */
+static void
+gpc_sCp(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+
+   if (in->a <= 128)
+   {
+      out->r = out->g = out->b = 255;
+      out->a = 0;
+   }
+
+   else
+   {
+      out->r = sRGB((double)in->r / in->a);
+      out->g = sRGB((double)in->g / in->a);
+      out->b = sRGB((double)in->b / in->a);
+      out->a = u8d(in->a / 257.);
+   }
+}
+
+/* gb16: composite linear onto background and convert to sRGB grayscale */
+/*  (order doesn't matter, the composite and grayscale operations permute) */
+static void
+gpc_gb16(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+      out->r = out->g = out->b = back->ig;
+
+   else if (in->a >= 65535)
+      out->r = out->g = out->b = isRGB(in->g);
+
+   else
+   {
+      double a = in->a / 65535.;
+      double a1 = 1-a;
+
+      a /= 65535;
+      out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1);
+   }
+
+   out->a = 255;
+}
+
+/* cb16: composite linear onto background and convert to sRGB */
+static void
+gpc_cb16(Pixel *out, const Pixel *in, const Background *back)
+{
+   if (in->a <= 0)
+   {
+      out->r = back->ir;
+      out->g = back->ig;
+      out->b = back->ib;
+   }
+
+   else if (in->a >= 65535)
+   {
+      out->r = isRGB(in->r);
+      out->g = isRGB(in->g);
+      out->b = isRGB(in->b);
+   }
+
+   else
+   {
+      double a = in->a / 65535.;
+      double a1 = 1-a;
+
+      a /= 65535;
+      out->r = sRGB(in->r * a + back->dr * a1);
+      out->g = sRGB(in->g * a + back->dg * a1);
+      out->b = sRGB(in->b * a + back->db * a1);
+   }
+
+   out->a = 255;
+}
+
+/* 16-bit to 16-bit conversions */
+/* A:    set alpha to 65535 */
+static void
+gpc_A(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   out->r = in->r;
+   out->g = in->g;
+   out->b = in->b;
+   out->a = 65535;
+}
+
+/* g16:  convert linear RGB to linear grayscale (alpha := 65535) */
+static void
+gpc_g16(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b));
+   out->a = 65535;
+}
+
+/* g16': as 'g16' but alpha is unchanged */
+static void
+gpc_g16q(Pixel *out, const Pixel *in, const Background *back)
+{
+   (void)back;
+   out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b));
+   out->a = in->a;
+}
+
+#if ALLOW_UNUSED_GPC
+/* Unused functions (to hide them from GCC unused function warnings) */
+void (* const gpc_unused[])
+   (Pixel *out, const Pixel *in, const Background *back) =
+{
+   gpc_Pre, gpc_Preq, gpc_Glin, gpc_Gpre, gpc_Gprq, gpc_nop8, gpc_nop6
+};
+#endif
+
+/*   OUT:    ----- 8-bit -----    ----- 16-bit -----
+ *   IN     G    GA   RGB  RGBA  G    GA   RGB  RGBA
+ *  8 G     .    .    .    .     lin  lin  lin  lin
+ *  8 GA    bckg .    bckc .     pre' pre  pre' pre
+ *  8 RGB   g8   g8   .    .     glin glin lin  lin
+ *  8 RGBA  g8b  g8   bckc .     gpr' gpre pre' pre
+ * 16 G     sRGB sRGB sRGB sRGB  .    .    .    .
+ * 16 GA    b16g unpg b16c unpc  A    .    A    .
+ * 16 RGB   sG   sG   sRGB sRGB  g16  g16  .    .
+ * 16 RGBA  gb16 sGp  cb16 sCp   g16  g16' A    .
+ *
+ * The matrix is held in an array indexed thus:
+ *
+ *   gpc_fn[out_format & BASE_FORMATS][in_format & BASE_FORMATS];
+ */
+/* This will produce a compile time error if the FORMAT_FLAG values don't
+ * match the above matrix!
+ */
+#if PNG_FORMAT_FLAG_ALPHA == 1 && PNG_FORMAT_FLAG_COLOR == 2 &&\
+   PNG_FORMAT_FLAG_LINEAR == 4
+static void (* const gpc_fn[8/*in*/][8/*out*/])
+   (Pixel *out, const Pixel *in, const Background *back) =
+{
+/*out: G-8     GA-8     RGB-8    RGBA-8    G-16     GA-16   RGB-16  RGBA-16 */
+   {gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_Lin, gpc_Lin, gpc_Lin, gpc_Lin },
+   {gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre },
+   {gpc_g8,  gpc_g8,  gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin },
+   {gpc_g8b, gpc_g8,  gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre },
+   {gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop},
+   {gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A,   gpc_noop,gpc_A,   gpc_noop},
+   {gpc_sG,  gpc_sG,  gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop},
+   {gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp,  gpc_g16, gpc_g16q,gpc_A,   gpc_noop}
+};
+
+/* The array is repeated for the cases where both the input and output are color
+ * mapped because then different algorithms are used.
+ */
+static void (* const gpc_fn_colormapped[8/*in*/][8/*out*/])
+   (Pixel *out, const Pixel *in, const Background *back) =
+{
+/*out: G-8     GA-8     RGB-8    RGBA-8    G-16     GA-16   RGB-16  RGBA-16 */
+   {gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_lin, gpc_lin, gpc_lin, gpc_lin },
+   {gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre },
+   {gpc_g8,  gpc_g8,  gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin },
+   {gpc_g8b, gpc_g8,  gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre },
+   {gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop},
+   {gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A,   gpc_noop,gpc_A,   gpc_noop},
+   {gpc_sG,  gpc_sG,  gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop},
+   {gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp,  gpc_g16, gpc_g16q,gpc_A,   gpc_noop}
+};
+
+/* The error arrays record the error in the same matrix; 64 entries, however
+ * the different algorithms used in libpng for colormap and direct conversions
+ * mean that four separate matrices are used (for each combination of
+ * colormapped and direct.)
+ *
+ * In some cases the conversion between sRGB formats goes via a linear
+ * intermediate; an sRGB to linear conversion (as above) is followed by a simple
+ * linear to sRGB step with no other conversions.  This is done by a separate
+ * error array from an arbitrary 'in' format to one of the four basic outputs
+ * (since final output is always sRGB not colormapped).
+ *
+ * These arrays may be modified if the --accumulate flag is set during the run;
+ * then instead of logging errors they are simply added in.
+ *
+ * The three entries are currently for transparent, partially transparent and
+ * opaque input pixel values.  Notice that alpha should be exact in each case.
+ *
+ * Errors in alpha should only occur when converting from a direct format
+ * to a colormapped format, when alpha is effectively smashed (so large
+ * errors can occur.)  There should be no error in the '0' and 'opaque'
+ * values.  The fourth entry in the array is used for the alpha error (and it
+ * should always be zero for the 'via linear' case since this is never color
+ * mapped.)
+ *
+ * Mapping to a colormap smashes the colors, it is necessary to have separate
+ * values for these cases because they are much larger; it is very much
+ * impossible to obtain a reasonable result, these are held in
+ * gpc_error_to_colormap.
+ */
+#if PNG_FORMAT_FLAG_COLORMAP == 8 /* extra check also required */
+#  include "pngstest-errors.h" /* machine generated */
+#endif /* COLORMAP flag check */
+#endif /* flag checks */
+
+typedef struct
+{
+   /* Basic pixel information: */
+   Image*       in_image;   /* Input image */
+   const Image* out_image;  /* Output image */
+
+   /* 'background' is the value passed to the gpc_ routines, it may be NULL if
+    * it should not be used (*this* program has an error if it crashes as a
+    * result!)
+    */
+   Background        background_color;
+   const Background* background;
+
+   /* Precalculated values: */
+   int          in_opaque;   /* Value of input alpha that is opaque */
+   int          is_palette;  /* Sample values come from the palette */
+   int          accumulate;  /* Accumulate component errors (don't log) */
+   int          output_8bit; /* Output is 8-bit (else 16-bit) */
+
+   void (*in_gp)(Pixel*, png_const_voidp);
+   void (*out_gp)(Pixel*, png_const_voidp);
+
+   void (*transform)(Pixel *out, const Pixel *in, const Background *back);
+      /* A function to perform the required transform */
+
+   void (*from_linear)(Pixel *out, const Pixel *in, const Background *back);
+      /* For 'via_linear' transforms the final, from linear, step, else NULL */
+
+   png_uint_16 error[4];
+      /* Three error values for transparent, partially transparent and opaque
+       * input pixels (in turn).
+       */
+
+   png_uint_16 *error_ptr;
+      /* Where these are stored in the static array (for 'accumulate') */
+}
+Transform;
+
+/* Return a 'transform' as above for the given format conversion. */
+static void
+transform_from_formats(Transform *result, Image *in_image,
+   const Image *out_image, png_const_colorp background, int via_linear)
+{
+   png_uint_32 in_format, out_format;
+   png_uint_32 in_base, out_base;
+
+   memset(result, 0, sizeof *result);
+
+   /* Store the original images for error messages */
+   result->in_image = in_image;
+   result->out_image = out_image;
+
+   in_format = in_image->image.format;
+   out_format = out_image->image.format;
+
+   if (in_format & PNG_FORMAT_FLAG_LINEAR)
+      result->in_opaque = 65535;
+   else
+      result->in_opaque = 255;
+
+   result->output_8bit = (out_format & PNG_FORMAT_FLAG_LINEAR) == 0;
+
+   result->is_palette = 0; /* set by caller if required */
+   result->accumulate = (in_image->opts & ACCUMULATE) != 0;
+
+   /* The loaders (which need the ordering information) */
+   result->in_gp = get_pixel(in_format);
+   result->out_gp = get_pixel(out_format);
+
+   /* Remove the ordering information: */
+   in_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP;
+   in_base = in_format & BASE_FORMATS;
+   out_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP;
+   out_base = out_format & BASE_FORMATS;
+
+   if (via_linear)
+   {
+      /* Check for an error in this program: */
+      if (out_format & (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLORMAP))
+      {
+         fprintf(stderr, "internal transform via linear error 0x%x->0x%x\n",
+            in_format, out_format);
+         exit(1);
+      }
+
+      result->transform = gpc_fn[in_base][out_base | PNG_FORMAT_FLAG_LINEAR];
+      result->from_linear = gpc_fn[out_base | PNG_FORMAT_FLAG_LINEAR][out_base];
+      result->error_ptr = gpc_error_via_linear[in_format][out_format];
+   }
+
+   else if (~in_format & out_format & PNG_FORMAT_FLAG_COLORMAP)
+   {
+      /* The input is not colormapped but the output is, the errors will
+       * typically be large (only the grayscale-no-alpha case permits preserving
+       * even 8-bit values.)
+       */
+      result->transform = gpc_fn[in_base][out_base];
+      result->from_linear = NULL;
+      result->error_ptr = gpc_error_to_colormap[in_base][out_base];
+   }
+
+   else
+   {
+      /* The caller handles the colormap->pixel value conversion, so the
+       * transform function just gets a pixel value, however because libpng
+       * currently contains a different implementation for mapping a colormap if
+       * both input and output are colormapped we need different conversion
+       * functions to deal with errors in the libpng implementation.
+       */
+      if (in_format & out_format & PNG_FORMAT_FLAG_COLORMAP)
+         result->transform = gpc_fn_colormapped[in_base][out_base];
+      else
+         result->transform = gpc_fn[in_base][out_base];
+      result->from_linear = NULL;
+      result->error_ptr = gpc_error[in_format][out_format];
+   }
+
+   /* Follow the libpng simplified API rules to work out what to pass to the gpc
+    * routines as a background value, if one is not required pass NULL so that
+    * this program crashes in the even of a programming error.
+    */
+   result->background = NULL; /* default: not required */
+
+   /* Rule 1: background only need be supplied if alpha is to be removed */
+   if (in_format & ~out_format & PNG_FORMAT_FLAG_ALPHA)
+   {
+      /* The input value is 'NULL' to use the background and (otherwise) an sRGB
+       * background color (to use a solid color).  The code above uses a fixed
+       * byte value, BUFFER_INIT8, for buffer even for 16-bit output.  For
+       * linear (16-bit) output the sRGB background color is ignored; the
+       * composition is always on the background (so BUFFER_INIT8 * 257), except
+       * that for the colormap (i.e. linear colormapped output) black is used.
+       */
+      result->background = &result->background_color;
+
+      if (out_format & PNG_FORMAT_FLAG_LINEAR || via_linear)
+      {
+         if (out_format & PNG_FORMAT_FLAG_COLORMAP)
+         {
+            result->background_color.ir =
+               result->background_color.ig =
+               result->background_color.ib = 0;
+            result->background_color.dr =
+               result->background_color.dg =
+               result->background_color.db = 0;
+         }
+
+         else
+         {
+            result->background_color.ir =
+               result->background_color.ig =
+               result->background_color.ib = BUFFER_INIT8 * 257;
+            result->background_color.dr =
+               result->background_color.dg =
+               result->background_color.db = 0;
+         }
+      }
+
+      else /* sRGB output */
+      {
+         if (background != NULL)
+         {
+            if (out_format & PNG_FORMAT_FLAG_COLOR)
+            {
+               result->background_color.ir = background->red;
+               result->background_color.ig = background->green;
+               result->background_color.ib = background->blue;
+               /* TODO: sometimes libpng uses the power law conversion here, how
+                * to handle this?
+                */
+               result->background_color.dr = sRGB_to_d[background->red];
+               result->background_color.dg = sRGB_to_d[background->green];
+               result->background_color.db = sRGB_to_d[background->blue];
+            }
+
+            else /* grayscale: libpng only looks at 'g' */
+            {
+               result->background_color.ir =
+                  result->background_color.ig =
+                  result->background_color.ib = background->green;
+               /* TODO: sometimes libpng uses the power law conversion here, how
+                * to handle this?
+                */
+               result->background_color.dr =
+                  result->background_color.dg =
+                  result->background_color.db = sRGB_to_d[background->green];
+            }
+         }
+
+         else if ((out_format & PNG_FORMAT_FLAG_COLORMAP) == 0)
+         {
+            result->background_color.ir =
+               result->background_color.ig =
+               result->background_color.ib = BUFFER_INIT8;
+            /* TODO: sometimes libpng uses the power law conversion here, how
+             * to handle this?
+             */
+            result->background_color.dr =
+               result->background_color.dg =
+               result->background_color.db = sRGB_to_d[BUFFER_INIT8];
+         }
+
+         /* Else the output is colormapped and a background color must be
+          * provided; if pngstest crashes then that is a bug in this program
+          * (though libpng should png_error as well.)
+          */
+         else
+            result->background = NULL;
+      }
+   }
+
+   if (result->background == NULL)
+   {
+      result->background_color.ir =
+         result->background_color.ig =
+         result->background_color.ib = -1; /* not used */
+      result->background_color.dr =
+         result->background_color.dg =
+         result->background_color.db = 1E30; /* not used */
+   }
+
+
+   /* Copy the error values into the Transform: */
+   result->error[0] = result->error_ptr[0];
+   result->error[1] = result->error_ptr[1];
+   result->error[2] = result->error_ptr[2];
+   result->error[3] = result->error_ptr[3];
+}
+
+
+/* Compare two pixels.
+ *
+ * OLD error values:
+static int error_to_linear = 811; * by experiment *
+static int error_to_linear_grayscale = 424; * by experiment *
+static int error_to_sRGB = 6; * by experiment *
+static int error_to_sRGB_grayscale = 17; * libpng error by calculation +
+                                            2 by experiment *
+static int error_in_compose = 2; * by experiment *
+static int error_in_premultiply = 1;
+ *
+ * The following is *just* the result of a round trip from 8-bit sRGB to linear
+ * then back to 8-bit sRGB when it is done by libpng.  There are two problems:
+ *
+ * 1) libpng currently uses a 2.2 power law with no linear segment, this results
+ * in instability in the low values and even with 16-bit precision sRGB(1) ends
+ * up mapping to sRGB(0) as a result of rounding in the 16-bit representation.
+ * This gives an error of 1 in the handling of value 1 only.
+ *
+ * 2) libpng currently uses an intermediate 8-bit linear value in gamma
+ * correction of 8-bit values.  This results in many more errors, the worse of
+ * which is mapping sRGB(14) to sRGB(0).
+ *
+ * The general 'error_via_linear' is more complex because of pre-multiplication,
+ * this compounds the 8-bit errors according to the alpha value of the pixel.
+ * As a result 256 values are pre-calculated for error_via_linear.
+ */
+#if 0
+static int error_in_libpng_gamma;
+static int error_via_linear[256]; /* Indexed by 8-bit alpha */
+
+static void
+init_error_via_linear(void)
+{
+   int alpha;
+
+   error_via_linear[0] = 255; /* transparent pixel */
+
+   for (alpha=1; alpha<=255; ++alpha)
+   {
+      /* 16-bit values less than 128.5 get rounded to 8-bit 0 and so the worst
+       * case error arises with 16-bit 128.5, work out what sRGB
+       * (non-associated) value generates 128.5; any value less than this is
+       * going to map to 0, so the worst error is floor(value).
+       *
+       * Note that errors are considerably higher (more than a factor of 2)
+       * because libpng uses a simple power law for sRGB data at present.
+       *
+       * Add .1 for arithmetic errors inside libpng.
+       */
+      double v = floor(255*pow(.5/*(128.5 * 255 / 65535)*/ / alpha, 1/2.2)+.1);
+
+      error_via_linear[alpha] = (int)v;
+   }
+
+   /* This is actually 14.99, but, despite the closeness to 15, 14 seems to work
+    * ok in this case.
+    */
+   error_in_libpng_gamma = 14;
+}
+#endif
+
+static void
+print_pixel(char string[64], const Pixel *pixel, png_uint_32 format)
+{
+   switch (format & (PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR))
+   {
+      case 0:
+         sprintf(string, "%s(%d)", format_names[format], pixel->g);
+         break;
+
+      case PNG_FORMAT_FLAG_ALPHA:
+         sprintf(string, "%s(%d,%d)", format_names[format], pixel->g,
+            pixel->a);
+         break;
+
+      case PNG_FORMAT_FLAG_COLOR:
+         sprintf(string, "%s(%d,%d,%d)", format_names[format],
+            pixel->r, pixel->g, pixel->b);
+         break;
+
+      case PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA:
+         sprintf(string, "%s(%d,%d,%d,%d)", format_names[format],
+            pixel->r, pixel->g, pixel->b, pixel->a);
+         break;
+
+      default:
+         sprintf(string, "invalid-format");
+         break;
+   }
+}
+
+static int
+logpixel(const Transform *transform, png_uint_32 x, png_uint_32 y,
+   const Pixel *in, const Pixel *calc, const Pixel *out, const char *reason)
+{
+   png_uint_32 in_format = transform->in_image->image.format;
+   png_uint_32 out_format = transform->out_image->image.format;
+
+   png_uint_32 back_format = out_format & ~PNG_FORMAT_FLAG_ALPHA;
+   const char *via_linear = "";
+
+   char pixel_in[64], pixel_calc[64], pixel_out[64], pixel_loc[64];
+   char background_info[100];
+
+   print_pixel(pixel_in, in, in_format);
+   print_pixel(pixel_calc, calc, out_format);
+   print_pixel(pixel_out, out, out_format);
+
+   if (transform->is_palette)
+      sprintf(pixel_loc, "palette: %lu", (unsigned long)y);
+   else
+      sprintf(pixel_loc, "%lu,%lu", (unsigned long)x, (unsigned long)y);
+
+   if (transform->from_linear != NULL)
+   {
+      via_linear = " (via linear)";
+      /* And as a result the *read* format which did any background processing
+       * was itself linear, so the background color information is also
+       * linear.
+       */
+      back_format |= PNG_FORMAT_FLAG_LINEAR;
+   }
+
+   if (transform->background != NULL)
+   {
+      Pixel back;
+      char pixel_back[64];
+
+      back.r = transform->background->ir;
+      back.g = transform->background->ig;
+      back.b = transform->background->ib;
+      back.a = -1; /* not used */
+
+      print_pixel(pixel_back, &back, back_format);
+      sprintf(background_info, " on background %s", pixel_back);
+   }
+
+   else
+      background_info[0] = 0;
+
+   if (transform->in_image->file_name != transform->out_image->file_name)
+   {
+      char error_buffer[512];
+      sprintf(error_buffer,
+         "(%s) %s error%s:\n %s%s ->\n       %s\n  not: %s.\n"
+         "Use --preserve and examine: ", pixel_loc, reason, via_linear,
+         pixel_in, background_info, pixel_out, pixel_calc);
+      return logerror(transform->in_image, transform->in_image->file_name,
+         error_buffer, transform->out_image->file_name);
+   }
+
+   else
+   {
+      char error_buffer[512];
+      sprintf(error_buffer,
+         "(%s) %s error%s:\n %s%s ->\n       %s\n  not: %s.\n"
+         " The error happened when reading the original file with this format.",
+         pixel_loc, reason, via_linear, pixel_in, background_info, pixel_out,
+         pixel_calc);
+      return logerror(transform->in_image, transform->in_image->file_name,
+         error_buffer, "");
+   }
+}
+
+static int
+cmppixel(Transform *transform, png_const_voidp in, png_const_voidp out,
+   png_uint_32 x, png_uint_32 y/*or palette index*/)
+{
+   int maxerr;
+   png_const_charp errmsg;
+   Pixel pixel_in, pixel_calc, pixel_out;
+
+   transform->in_gp(&pixel_in, in);
+
+   if (transform->from_linear == NULL)
+      transform->transform(&pixel_calc, &pixel_in, transform->background);
+
+   else
+   {
+      transform->transform(&pixel_out, &pixel_in, transform->background);
+      transform->from_linear(&pixel_calc, &pixel_out, NULL);
+   }
+
+   transform->out_gp(&pixel_out, out);
+
+   /* Eliminate the case where the input and output values match exactly. */
+   if (pixel_calc.a == pixel_out.a && pixel_calc.r == pixel_out.r &&
+      pixel_calc.g == pixel_out.g && pixel_calc.b == pixel_out.b)
+      return 1;
+
+   /* Eliminate the case where the output pixel is transparent and the output
+    * is 8-bit - any component values are valid.  Don't check the input alpha
+    * here to also skip the 16-bit small alpha cases.
+    */
+   if (transform->output_8bit && pixel_calc.a == 0 && pixel_out.a == 0)
+      return 1;
+
+   /* Check for alpha errors first; an alpha error can damage the components too
+    * so avoid spurious checks on components if one is found.
+    */
+   errmsg = NULL;
+   {
+      int err_a = abs(pixel_calc.a-pixel_out.a);
+
+      if (err_a > transform->error[3])
+      {
+         /* If accumulating check the components too */
+         if (transform->accumulate)
+            transform->error[3] = (png_uint_16)err_a;
+
+         else
+            errmsg = "alpha";
+      }
+   }
+
+   /* Now if *either* of the output alphas are 0 but alpha is within tolerance
+    * eliminate the 8-bit component comparison.
+    */
+   if (errmsg == NULL && transform->output_8bit &&
+      (pixel_calc.a == 0 || pixel_out.a == 0))
+      return 1;
+
+   if (errmsg == NULL) /* else just signal an alpha error */
+   {
+      int err_r = abs(pixel_calc.r - pixel_out.r);
+      int err_g = abs(pixel_calc.g - pixel_out.g);
+      int err_b = abs(pixel_calc.b - pixel_out.b);
+      int limit;
+
+      if ((err_r | err_g | err_b) == 0)
+         return 1; /* exact match */
+
+      /* Mismatch on a component, check the input alpha */
+      if (pixel_in.a >= transform->in_opaque)
+      {
+         errmsg = "opaque component";
+         limit = 2; /* opaque */
+      }
+
+      else if (pixel_in.a > 0)
+      {
+         errmsg = "alpha component";
+         limit = 1; /* partially transparent */
+      }
+
+      else
+      {
+         errmsg = "transparent component (background)";
+         limit = 0; /* transparent */
+      }
+
+      maxerr = err_r;
+      if (maxerr < err_g) maxerr = err_g;
+      if (maxerr < err_b) maxerr = err_b;
+
+      if (maxerr <= transform->error[limit])
+         return 1; /* within the error limits */
+
+      /* Handle a component mis-match; log it, just return an error code, or
+       * accumulate it.
+       */
+      if (transform->accumulate)
+      {
+         transform->error[limit] = (png_uint_16)maxerr;
+         return 1; /* to cause the caller to keep going */
+      }
+   }
+
+   /* Failure to match and not accumulating, so the error must be logged. */
+   return logpixel(transform, x, y, &pixel_in, &pixel_calc, &pixel_out, errmsg);
+}
+
+static png_byte
+component_loc(png_byte loc[4], png_uint_32 format)
+{
+   /* Given a format return the number of channels and the location of
+    * each channel.
+    *
+    * The mask 'loc' contains the component offset of the channels in the
+    * following order.  Note that if 'format' is grayscale the entries 1-3 must
+    * all contain the location of the gray channel.
+    *
+    * 0: alpha
+    * 1: red or gray
+    * 2: green or gray
+    * 3: blue or gray
+    */
+   png_byte channels;
+
+   if (format & PNG_FORMAT_FLAG_COLOR)
+   {
+      channels = 3;
+
+      loc[2] = 1;
+
+#     ifdef PNG_FORMAT_BGR_SUPPORTED
+         if (format & PNG_FORMAT_FLAG_BGR)
+         {
+            loc[1] = 2;
+            loc[3] = 0;
+         }
+
+         else
+#     endif
+      {
+         loc[1] = 0;
+         loc[3] = 2;
+      }
+   }
+
+   else
+   {
+      channels = 1;
+      loc[1] = loc[2] = loc[3] = 0;
+   }
+
+   if (format & PNG_FORMAT_FLAG_ALPHA)
+   {
+#     ifdef PNG_FORMAT_AFIRST_SUPPORTED
+         if (format & PNG_FORMAT_FLAG_AFIRST)
+         {
+            loc[0] = 0;
+            ++loc[1];
+            ++loc[2];
+            ++loc[3];
+         }
+
+         else
+#     endif
+         loc[0] = channels;
+
+      ++channels;
+   }
+
+   else
+      loc[0] = 4; /* not present */
+
+   return channels;
+}
+
+/* Compare two images, the original 'a', which was written out then read back in
+ * to * give image 'b'.  The formats may have been changed.
+ */
+static int
+compare_two_images(Image *a, Image *b, int via_linear,
+   png_const_colorp background)
+{
+   ptrdiff_t stridea = a->stride;
+   ptrdiff_t strideb = b->stride;
+   png_const_bytep rowa = a->buffer+16;
+   png_const_bytep rowb = b->buffer+16;
+   png_uint_32 width = a->image.width;
+   png_uint_32 height = a->image.height;
+   png_uint_32 formata = a->image.format;
+   png_uint_32 formatb = b->image.format;
+   unsigned int a_sample = PNG_IMAGE_SAMPLE_SIZE(formata);
+   unsigned int b_sample = PNG_IMAGE_SAMPLE_SIZE(formatb);
+   int alpha_added, alpha_removed;
+   int bchannels;
+   png_uint_32 y;
+   Transform tr;
+   int btoa[4]={0,0,0,0};
+
+   /* This should never happen: */
+   if (width != b->image.width || height != b->image.height)
+      return logerror(a, a->file_name, ": width x height changed: ",
+         b->file_name);
+
+   /* Set up the background and the transform */
+   transform_from_formats(&tr, a, b, background, via_linear);
+
+   /* Find the first row and inter-row space. */
+   if (!(formata & PNG_FORMAT_FLAG_COLORMAP) &&
+      (formata & PNG_FORMAT_FLAG_LINEAR))
+      stridea *= 2;
+
+   if (!(formatb & PNG_FORMAT_FLAG_COLORMAP) &&
+      (formatb & PNG_FORMAT_FLAG_LINEAR))
+      strideb *= 2;
+
+   if (stridea < 0) rowa += (height-1) * (-stridea);
+   if (strideb < 0) rowb += (height-1) * (-strideb);
+
+   /* First shortcut the two colormap case by comparing the image data; if it
+    * matches then we expect the colormaps to match, although this is not
+    * absolutely necessary for an image match.  If the colormaps fail to match
+    * then there is a problem in libpng.
+    */
+   if (formata & formatb & PNG_FORMAT_FLAG_COLORMAP)
+   {
+      /* Only check colormap entries that actually exist; */
+      png_const_bytep ppa, ppb;
+      int match;
+      png_byte in_use[256], amax = 0, bmax = 0;
+
+      memset(in_use, 0, sizeof in_use);
+
+      ppa = rowa;
+      ppb = rowb;
+
+      /* Do this the slow way to accumulate the 'in_use' flags, don't break out
+       * of the loop until the end; this validates the color-mapped data to
+       * ensure all pixels are valid color-map indexes.
+       */
+      for (y=0, match=1; y<height && match; ++y, ppa += stridea, ppb += strideb)
+      {
+         png_uint_32 x;
+
+         for (x=0; x<width; ++x)
+         {
+            png_byte bval = ppb[x];
+            png_byte aval = ppa[x];
+
+            if (bval > bmax)
+               bmax = bval;
+
+            if (bval != aval)
+               match = 0;
+
+            in_use[aval] = 1;
+            if (aval > amax)
+               amax = aval;
+         }
+      }
+
+      /* If the buffers match then the colormaps must too. */
+      if (match)
+      {
+         /* Do the color-maps match, entry by entry?  Only check the 'in_use'
+          * entries.  An error here should be logged as a color-map error.
+          */
+         png_const_bytep a_cmap = (png_const_bytep)a->colormap;
+         png_const_bytep b_cmap = (png_const_bytep)b->colormap;
+         int result = 1; /* match by default */
+
+         /* This is used in logpixel to get the error message correct. */
+         tr.is_palette = 1;
+
+         for (y=0; y<256; ++y, a_cmap += a_sample, b_cmap += b_sample)
+            if (in_use[y])
+         {
+            /* The colormap entries should be valid, but because libpng doesn't
+             * do any checking at present the original image may contain invalid
+             * pixel values.  These cause an error here (at present) unless
+             * accumulating errors in which case the program just ignores them.
+             */
+            if (y >= a->image.colormap_entries)
+            {
+               if ((a->opts & ACCUMULATE) == 0)
+               {
+                  char pindex[16];
+                  sprintf(pindex, "%lu[%lu]", (unsigned long)y,
+                     (unsigned long)a->image.colormap_entries);
+                  logerror(a, a->file_name, ": bad pixel index: ", pindex);
+               }
+               result = 0;
+            }
+
+            else if (y >= b->image.colormap_entries)
+            {
+               if ((b->opts & ACCUMULATE) == 0)
+               {
+                  char pindex[16];
+                  sprintf(pindex, "%lu[%lu]", (unsigned long)y,
+                     (unsigned long)b->image.colormap_entries);
+                  logerror(b, b->file_name, ": bad pixel index: ", pindex);
+               }
+               result = 0;
+            }
+
+            /* All the mismatches are logged here; there can only be 256! */
+            else if (!cmppixel(&tr, a_cmap, b_cmap, 0, y))
+               result = 0;
+         }
+
+         /* If requested, copy the error values back from the Transform. */
+         if (a->opts & ACCUMULATE)
+         {
+            tr.error_ptr[0] = tr.error[0];
+            tr.error_ptr[1] = tr.error[1];
+            tr.error_ptr[2] = tr.error[2];
+            tr.error_ptr[3] = tr.error[3];
+            result = 1; /* force a continue */
+         }
+
+         return result;
+      }
+
+      /* else the image buffers don't match pixel-wise so compare sample values
+       * instead, but first validate that the pixel indexes are in range (but
+       * only if not accumulating, when the error is ignored.)
+       */
+      else if ((a->opts & ACCUMULATE) == 0)
+      {
+#        ifdef __GNUC__
+#           define BYTE_CHARS 20 /* 2^32: GCC sprintf warning */
+#        else
+#           define BYTE_CHARS 3 /* 2^8: real maximum value */
+#        endif
+         /* Check the original image first,
+          * TODO: deal with input images with bad pixel values?
+          */
+         if (amax >= a->image.colormap_entries)
+         {
+            char pindex[3+2*BYTE_CHARS];
+            sprintf(pindex, "%d[%u]", amax,
+               (png_byte)/*SAFE*/a->image.colormap_entries);
+            return logerror(a, a->file_name, ": bad pixel index: ", pindex);
+         }
+
+         else if (bmax >= b->image.colormap_entries)
+         {
+            char pindex[3+2*BYTE_CHARS];
+            sprintf(pindex, "%d[%u]", bmax,
+               (png_byte)/*SAFE*/b->image.colormap_entries);
+            return logerror(b, b->file_name, ": bad pixel index: ", pindex);
+         }
+      }
+   }
+
+   /* We can directly compare pixel values without the need to use the read
+    * or transform support (i.e. a memory compare) if:
+    *
+    * 1) The bit depth has not changed.
+    * 2) RGB to grayscale has not been done (the reverse is ok; we just compare
+    *    the three RGB values to the original grayscale.)
+    * 3) An alpha channel has not been removed from an 8-bit format, or the
+    *    8-bit alpha value of the pixel was 255 (opaque).
+    *
+    * If an alpha channel has been *added* then it must have the relevant opaque
+    * value (255 or 65535).
+    *
+    * The fist two the tests (in the order given above) (using the boolean
+    * equivalence !a && !b == !(a || b))
+    */
+   if (!(((formata ^ formatb) & PNG_FORMAT_FLAG_LINEAR) |
+      (formata & (formatb ^ PNG_FORMAT_FLAG_COLOR) & PNG_FORMAT_FLAG_COLOR)))
+   {
+      /* Was an alpha channel changed? */
+      png_uint_32 alpha_changed = (formata ^ formatb) & PNG_FORMAT_FLAG_ALPHA;
+
+      /* Was an alpha channel removed?  (The third test.)  If so the direct
+       * comparison is only possible if the input alpha is opaque.
+       */
+      alpha_removed = (formata & alpha_changed) != 0;
+
+      /* Was an alpha channel added? */
+      alpha_added = (formatb & alpha_changed) != 0;
+
+      /* The channels may have been moved between input and output, this finds
+       * out how, recording the result in the btoa array, which says where in
+       * 'a' to find each channel of 'b'.  If alpha was added then btoa[alpha]
+       * ends up as 4 (and is not used.)
+       */
+      {
+         int i;
+         png_byte aloc[4];
+         png_byte bloc[4];
+
+         /* The following are used only if the formats match, except that
+          * 'bchannels' is a flag for matching formats.  btoa[x] says, for each
+          * channel in b, where to find the corresponding value in a, for the
+          * bchannels.  achannels may be different for a gray to rgb transform
+          * (a will be 1 or 2, b will be 3 or 4 channels.)
+          */
+         (void)component_loc(aloc, formata);
+         bchannels = component_loc(bloc, formatb);
+
+         /* Hence the btoa array. */
+         for (i=0; i<4; ++i)
+         {
+            if (bloc[i] < 4)
+               btoa[bloc[i]] = aloc[i]; /* may be '4' for alpha */
+         }
+
+         if (alpha_added)
+            alpha_added = bloc[0]; /* location of alpha channel in image b */
+
+         else
+            alpha_added = 4; /* Won't match an image b channel */
+
+         if (alpha_removed)
+            alpha_removed = aloc[0]; /* location of alpha channel in image a */
+
+         else
+            alpha_removed = 4;
+      }
+   }
+
+   else
+   {
+      /* Direct compare is not possible, cancel out all the corresponding local
+       * variables.
+       */
+      bchannels = 0;
+      alpha_removed = alpha_added = 4;
+      btoa[3] = btoa[2] = btoa[1] = btoa[0] = 4; /* 4 == not present */
+   }
+
+   for (y=0; y<height; ++y, rowa += stridea, rowb += strideb)
+   {
+      png_const_bytep ppa, ppb;
+      png_uint_32 x;
+
+      for (x=0, ppa=rowa, ppb=rowb; x<width; ++x)
+      {
+         png_const_bytep psa, psb;
+
+         if (formata & PNG_FORMAT_FLAG_COLORMAP)
+            psa = (png_const_bytep)a->colormap + a_sample * *ppa++;
+         else
+            psa = ppa, ppa += a_sample;
+
+         if (formatb & PNG_FORMAT_FLAG_COLORMAP)
+            psb = (png_const_bytep)b->colormap + b_sample * *ppb++;
+         else
+            psb = ppb, ppb += b_sample;
+
+         /* Do the fast test if possible. */
+         if (bchannels)
+         {
+            /* Check each 'b' channel against either the corresponding 'a'
+             * channel or the opaque alpha value, as appropriate.  If
+             * alpha_removed value is set (not 4) then also do this only if the
+             * 'a' alpha channel (alpha_removed) is opaque; only relevant for
+             * the 8-bit case.
+             */
+            if (formatb & PNG_FORMAT_FLAG_LINEAR) /* 16-bit checks */
+            {
+               png_const_uint_16p pua = aligncastconst(png_const_uint_16p, psa);
+               png_const_uint_16p pub = aligncastconst(png_const_uint_16p, psb);
+
+               switch (bchannels)
+               {
+                  case 4:
+                     if (pua[btoa[3]] != pub[3]) break;
+                     /* FALLTHROUGH */
+                  case 3:
+                     if (pua[btoa[2]] != pub[2]) break;
+                     /* FALLTHROUGH */
+                  case 2:
+                     if (pua[btoa[1]] != pub[1]) break;
+                     /* FALLTHROUGH */
+                  case 1:
+                     if (pua[btoa[0]] != pub[0]) break;
+                     if (alpha_added != 4 && pub[alpha_added] != 65535) break;
+                     continue; /* x loop */
+                  default:
+                     break; /* impossible */
+               }
+            }
+
+            else if (alpha_removed == 4 || psa[alpha_removed] == 255)
+            {
+               switch (bchannels)
+               {
+                  case 4:
+                     if (psa[btoa[3]] != psb[3]) break;
+                     /* FALLTHROUGH */
+                  case 3:
+                     if (psa[btoa[2]] != psb[2]) break;
+                     /* FALLTHROUGH */
+                  case 2:
+                     if (psa[btoa[1]] != psb[1]) break;
+                     /* FALLTHROUGH */
+                  case 1:
+                     if (psa[btoa[0]] != psb[0]) break;
+                     if (alpha_added != 4 && psb[alpha_added] != 255) break;
+                     continue; /* x loop */
+                  default:
+                     break; /* impossible */
+               }
+            }
+         }
+
+         /* If we get to here the fast match failed; do the slow match for this
+          * pixel.
+          */
+         if (!cmppixel(&tr, psa, psb, x, y) && (a->opts & KEEP_GOING) == 0)
+            return 0; /* error case */
+      }
+   }
+
+   /* If requested, copy the error values back from the Transform. */
+   if (a->opts & ACCUMULATE)
+   {
+      tr.error_ptr[0] = tr.error[0];
+      tr.error_ptr[1] = tr.error[1];
+      tr.error_ptr[2] = tr.error[2];
+      tr.error_ptr[3] = tr.error[3];
+   }
+
+   return 1;
+}
+
+/* Read the file; how the read gets done depends on which of input_file and
+ * input_memory have been set.
+ */
+static int
+read_file(Image *image, png_uint_32 format, png_const_colorp background)
+{
+   memset(&image->image, 0, sizeof image->image);
+   image->image.version = PNG_IMAGE_VERSION;
+
+   if (image->input_memory != NULL)
+   {
+      if (!png_image_begin_read_from_memory(&image->image, image->input_memory,
+         image->input_memory_size))
+         return logerror(image, "memory init: ", image->file_name, "");
+   }
+
+#  ifdef PNG_STDIO_SUPPORTED
+      else if (image->input_file != NULL)
+      {
+         if (!png_image_begin_read_from_stdio(&image->image, image->input_file))
+            return logerror(image, "stdio init: ", image->file_name, "");
+      }
+
+      else
+      {
+         if (!png_image_begin_read_from_file(&image->image, image->file_name))
+            return logerror(image, "file init: ", image->file_name, "");
+      }
+#  else
+      else
+      {
+         return logerror(image, "unsupported file/stdio init: ",
+            image->file_name, "");
+      }
+#  endif
+
+   /* This must be set after the begin_read call: */
+   if (image->opts & sRGB_16BIT)
+      image->image.flags |= PNG_IMAGE_FLAG_16BIT_sRGB;
+
+   /* Have an initialized image with all the data we need plus, maybe, an
+    * allocated file (myfile) or buffer (mybuffer) that need to be freed.
+    */
+   {
+      int result;
+      png_uint_32 image_format;
+
+      /* Print both original and output formats. */
+      image_format = image->image.format;
+
+      if (image->opts & VERBOSE)
+      {
+         printf("%s %lu x %lu %s -> %s", image->file_name,
+            (unsigned long)image->image.width,
+            (unsigned long)image->image.height,
+            format_names[image_format & FORMAT_MASK],
+            (format & FORMAT_NO_CHANGE) != 0 || image->image.format == format
+            ? "no change" : format_names[format & FORMAT_MASK]);
+
+         if (background != NULL)
+            printf(" background(%d,%d,%d)\n", background->red,
+               background->green, background->blue);
+         else
+            printf("\n");
+
+         fflush(stdout);
+      }
+
+      /* 'NO_CHANGE' combined with the color-map flag forces the base format
+       * flags to be set on read to ensure that the original representation is
+       * not lost in the pass through a colormap format.
+       */
+      if ((format & FORMAT_NO_CHANGE) != 0)
+      {
+         if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 &&
+            (image_format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+            format = (image_format & ~BASE_FORMATS) | (format & BASE_FORMATS);
+
+         else
+            format = image_format;
+      }
+
+      image->image.format = format;
+
+      image->stride = PNG_IMAGE_ROW_STRIDE(image->image) + image->stride_extra;
+      allocbuffer(image);
+
+      result = png_image_finish_read(&image->image, background,
+         image->buffer+16, (png_int_32)image->stride, image->colormap);
+
+      checkbuffer(image, image->file_name);
+
+      if (result)
+         return checkopaque(image);
+
+      else
+         return logerror(image, image->file_name, ": image read failed", "");
+   }
+}
+
+/* Reads from a filename, which must be in image->file_name, but uses
+ * image->opts to choose the method.  The file is always read in its native
+ * format (the one the simplified API suggests).
+ */
+static int
+read_one_file(Image *image)
+{
+   if (!(image->opts & USE_FILE) || (image->opts & USE_STDIO))
+   {
+      /* memory or stdio. */
+      FILE *f = fopen(image->file_name, "rb");
+
+      if (f != NULL)
+      {
+         if (image->opts & USE_FILE)
+            image->input_file = f;
+
+         else /* memory */
+         {
+            if (fseek(f, 0, SEEK_END) == 0)
+            {
+               long int cb = ftell(f);
+
+               if (cb > 0)
+               {
+#ifndef __COVERITY__
+                  if ((unsigned long int)cb <= (size_t)~(size_t)0)
+#endif
+                  {
+                     png_bytep b = voidcast(png_bytep, malloc((size_t)cb));
+
+                     if (b != NULL)
+                     {
+                        rewind(f);
+
+                        if (fread(b, (size_t)cb, 1, f) == 1)
+                        {
+                           fclose(f);
+                           image->input_memory_size = cb;
+                           image->input_memory = b;
+                        }
+
+                        else
+                        {
+                           free(b);
+                           return logclose(image, f, image->file_name,
+                              ": read failed: ");
+                        }
+                     }
+
+                     else
+                        return logclose(image, f, image->file_name,
+                           ": out of memory: ");
+                  }
+
+                  else
+                     return logclose(image, f, image->file_name,
+                        ": file too big for this architecture: ");
+                     /* cb is the length of the file as a (long) and
+                      * this is greater than the maximum amount of
+                      * memory that can be requested from malloc.
+                      */
+               }
+
+               else if (cb == 0)
+                  return logclose(image, f, image->file_name,
+                     ": zero length: ");
+
+               else
+                  return logclose(image, f, image->file_name,
+                     ": tell failed: ");
+            }
+
+            else
+               return logclose(image, f, image->file_name, ": seek failed: ");
+         }
+      }
+
+      else
+         return logerror(image, image->file_name, ": open failed: ",
+            strerror(errno));
+   }
+
+   return read_file(image, FORMAT_NO_CHANGE, NULL);
+}
+
+#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+static int
+write_one_file(Image *output, Image *image, int convert_to_8bit)
+{
+   if (image->opts & FAST_WRITE)
+      image->image.flags |= PNG_IMAGE_FLAG_FAST;
+
+   if (image->opts & USE_STDIO)
+   {
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+#ifndef __COVERITY__
+      FILE *f = tmpfile();
+#else
+      /* Experimental. Coverity says tmpfile() is insecure because it
+       * generates predictable names.
+       *
+       * It is possible to satisfy Coverity by using mkstemp(); however,
+       * any platform supporting mkstemp() undoubtedly has a secure tmpfile()
+       * implementation as well, and doesn't need the fix.  Note that
+       * the fix won't work on platforms that don't support mkstemp().
+       *
+       * https://www.securecoding.cert.org/confluence/display/c/
+       * FIO21-C.+Do+not+create+temporary+files+in+shared+directories
+       * says that most historic implementations of tmpfile() provide
+       * only a limited number of possible temporary file names
+       * (usually 26) before file names are recycled. That article also
+       * provides a secure solution that unfortunately depends upon mkstemp().
+       */
+      char tmpfile[] = "pngstest-XXXXXX";
+      int filedes;
+      FILE *f;
+      umask(0177);
+      filedes = mkstemp(tmpfile);
+      if (filedes < 0)
+        f = NULL;
+      else
+      {
+        f = fdopen(filedes,"w+");
+        /* Hide the filename immediately and ensure that the file does
+         * not exist after the program ends
+         */
+        (void) unlink(tmpfile);
+      }
+#endif
+
+      if (f != NULL)
+      {
+         if (png_image_write_to_stdio(&image->image, f, convert_to_8bit,
+            image->buffer+16, (png_int_32)image->stride, image->colormap))
+         {
+            if (fflush(f) == 0)
+            {
+               rewind(f);
+               initimage(output, image->opts, "tmpfile", image->stride_extra);
+               output->input_file = f;
+               if (!checkopaque(image))
+                  return 0;
+            }
+
+            else
+               return logclose(image, f, "tmpfile", ": flush: ");
+         }
+
+         else
+         {
+            fclose(f);
+            return logerror(image, "tmpfile", ": write failed", "");
+         }
+      }
+
+      else
+         return logerror(image, "tmpfile", ": open: ", strerror(errno));
+#else /* SIMPLIFIED_WRITE_STDIO */
+      return logerror(image, "tmpfile", ": open: unsupported", "");
+#endif /* SIMPLIFIED_WRITE_STDIO */
+   }
+
+   else if (image->opts & USE_FILE)
+   {
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+      static unsigned int counter = 0;
+      char name[32];
+
+      sprintf(name, "%s%u.png", tmpf, ++counter);
+
+      if (png_image_write_to_file(&image->image, name, convert_to_8bit,
+         image->buffer+16, (png_int_32)image->stride, image->colormap))
+      {
+         initimage(output, image->opts, output->tmpfile_name,
+            image->stride_extra);
+         /* Afterwards, or freeimage will delete it! */
+         strcpy(output->tmpfile_name, name);
+
+         if (!checkopaque(image))
+            return 0;
+      }
+
+      else
+         return logerror(image, name, ": write failed", "");
+#else /* SIMPLIFIED_WRITE_STDIO */
+      return logerror(image, "stdio", ": open: unsupported", "");
+#endif /* SIMPLIFIED_WRITE_STDIO */
+   }
+
+   else /* use memory */
+   {
+      png_alloc_size_t size;
+
+      if (png_image_write_get_memory_size(image->image, size, convert_to_8bit,
+               image->buffer+16, (png_int_32)image->stride, image->colormap))
+      {
+         /* This is non-fatal but ignoring it was causing serious problems in
+          * the macro to be ignored:
+          */
+         if (size > PNG_IMAGE_PNG_SIZE_MAX(image->image))
+            return logerror(image, "memory", ": PNG_IMAGE_SIZE_MAX wrong", "");
+
+         initimage(output, image->opts, "memory", image->stride_extra);
+         output->input_memory = malloc(size);
+
+         if (output->input_memory != NULL)
+         {
+            output->input_memory_size = size;
+
+            if (png_image_write_to_memory(&image->image, output->input_memory,
+                  &output->input_memory_size, convert_to_8bit, image->buffer+16,
+                  (png_int_32)image->stride, image->colormap))
+            {
+               /* This is also non-fatal but it safes safer to error out anyway:
+                */
+               if (size != output->input_memory_size)
+                  return logerror(image, "memory", ": memory size wrong", "");
+            }
+
+            else
+               return logerror(image, "memory", ": write failed", "");
+         }
+
+         else
+            return logerror(image, "memory", ": out of memory", "");
+      }
+
+      else
+         return logerror(image, "memory", ": get size:", "");
+   }
+
+   /* 'output' has an initialized temporary image, read this back in and compare
+    * this against the original: there should be no change since the original
+    * format was written unmodified unless 'convert_to_8bit' was specified.
+    * However, if the original image was color-mapped, a simple read will zap
+    * the linear, color and maybe alpha flags, this will cause spurious failures
+    * under some circumstances.
+    */
+   if (read_file(output, image->image.format | FORMAT_NO_CHANGE, NULL))
+   {
+      png_uint_32 original_format = image->image.format;
+
+      if (convert_to_8bit)
+         original_format &= ~PNG_FORMAT_FLAG_LINEAR;
+
+      if ((output->image.format & BASE_FORMATS) !=
+         (original_format & BASE_FORMATS))
+         return logerror(image, image->file_name, ": format changed on read: ",
+            output->file_name);
+
+      return compare_two_images(image, output, 0/*via linear*/, NULL);
+   }
+
+   else
+      return logerror(output, output->tmpfile_name,
+         ": read of new file failed", "");
+}
+#endif
+
+static int
+testimage(Image *image, png_uint_32 opts, format_list *pf)
+{
+   int result;
+   Image copy;
+
+   /* Copy the original data, stealing it from 'image' */
+   checkopaque(image);
+   copy = *image;
+
+   copy.opts = opts;
+   copy.buffer = NULL;
+   copy.bufsize = 0;
+   copy.allocsize = 0;
+
+   image->input_file = NULL;
+   image->input_memory = NULL;
+   image->input_memory_size = 0;
+   image->tmpfile_name[0] = 0;
+
+   {
+      png_uint_32 counter;
+      Image output;
+
+      newimage(&output);
+
+      result = 1;
+
+      /* Use the low bit of 'counter' to indicate whether or not to do alpha
+       * removal with a background color or by composting onto the image; this
+       * step gets skipped if it isn't relevant
+       */
+      for (counter=0; counter<2*FORMAT_COUNT; ++counter)
+         if (format_isset(pf, counter >> 1))
+      {
+         png_uint_32 format = counter >> 1;
+
+         png_color background_color;
+         png_colorp background = NULL;
+
+         /* If there is a format change that removes the alpha channel then
+          * the background is relevant.  If the output is 8-bit color-mapped
+          * then a background color *must* be provided, otherwise there are
+          * two tests to do - one with a color, the other with NULL.  The
+          * NULL test happens second.
+          */
+         if ((counter & 1) == 0)
+         {
+            if ((format & PNG_FORMAT_FLAG_ALPHA) == 0 &&
+               (image->image.format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            {
+               /* Alpha/transparency will be removed, the background is
+                * relevant: make it a color the first time
+                */
+               random_color(&background_color);
+               background = &background_color;
+
+               /* BUT if the output is to a color-mapped 8-bit format then
+                * the background must always be a color, so increment 'counter'
+                * to skip the NULL test.
+                */
+               if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 &&
+                  (format & PNG_FORMAT_FLAG_LINEAR) == 0)
+                  ++counter;
+            }
+
+            /* Otherwise an alpha channel is not being eliminated, just leave
+             * background NULL and skip the (counter & 1) NULL test.
+             */
+            else
+               ++counter;
+         }
+         /* else just use NULL for background */
+
+         resetimage(&copy);
+         copy.opts = opts; /* in case read_file needs to change it */
+
+         result = read_file(&copy, format, background);
+         if (!result)
+            break;
+
+         /* Make sure the file just read matches the original file. */
+         result = compare_two_images(image, &copy, 0/*via linear*/, background);
+         if (!result)
+            break;
+
+#        ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+            /* Write the *copy* just made to a new file to make sure the write
+             * side works ok.  Check the conversion to sRGB if the copy is
+             * linear.
+             */
+            output.opts = opts;
+            result = write_one_file(&output, &copy, 0/*convert to 8bit*/);
+            if (!result)
+               break;
+
+            /* Validate against the original too; the background is needed here
+             * as well so that compare_two_images knows what color was used.
+             */
+            result = compare_two_images(image, &output, 0, background);
+            if (!result)
+               break;
+
+            if ((format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
+               (format & PNG_FORMAT_FLAG_COLORMAP) == 0)
+            {
+               /* 'output' is linear, convert to the corresponding sRGB format.
+                */
+               output.opts = opts;
+               result = write_one_file(&output, &copy, 1/*convert to 8bit*/);
+               if (!result)
+                  break;
+
+               /* This may involve a conversion via linear; in the ideal world
+                * this would round-trip correctly, but libpng 1.5.7 is not the
+                * ideal world so allow a drift (error_via_linear).
+                *
+                * 'image' has an alpha channel but 'output' does not then there
+                * will a strip-alpha-channel operation (because 'output' is
+                * linear), handle this by composing on black when doing the
+                * comparison.
+                */
+               result = compare_two_images(image, &output, 1/*via_linear*/,
+                  background);
+               if (!result)
+                  break;
+            }
+#        endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */
+      }
+
+      freeimage(&output);
+   }
+
+   freeimage(&copy);
+
+   return result;
+}
+
+static int
+test_one_file(const char *file_name, format_list *formats, png_uint_32 opts,
+   int stride_extra, int log_pass)
+{
+   int result;
+   Image image;
+
+   if (!(opts & NO_RESEED))
+      reseed(); /* ensure that the random numbers don't depend on file order */
+   newimage(&image);
+   initimage(&image, opts, file_name, stride_extra);
+   result = read_one_file(&image);
+   if (result)
+      result = testimage(&image, opts, formats);
+   freeimage(&image);
+
+   /* Ensure that stderr is flushed into any log file */
+   fflush(stderr);
+
+   if (log_pass)
+   {
+      if (result)
+         printf("PASS:");
+
+      else
+         printf("FAIL:");
+
+#     ifndef PNG_SIMPLIFIED_WRITE_SUPPORTED
+         printf(" (no write)");
+#     endif
+
+      print_opts(opts);
+      printf(" %s\n", file_name);
+      /* stdout may not be line-buffered if it is piped to a file, so: */
+      fflush(stdout);
+   }
+
+   else if (!result)
+      exit(1);
+
+   return result;
+}
+
+int
+main(int argc, char **argv)
+{
+   png_uint_32 opts = FAST_WRITE | STRICT;
+   format_list formats;
+   const char *touch = NULL;
+   int log_pass = 0;
+   int redundant = 0;
+   int stride_extra = 0;
+   int retval = 0;
+   int c;
+
+#if PNG_LIBPNG_VER >= 10700
+      /* This error should not exist in 1.7 or later: */
+      opts |= GBG_ERROR;
+#endif
+
+   init_sRGB_to_d();
+#if 0
+   init_error_via_linear();
+#endif
+   format_init(&formats);
+   reseed(); /* initialize random number seeds */
+
+   for (c=1; c<argc; ++c)
+   {
+      const char *arg = argv[c];
+
+      if (strcmp(arg, "--log") == 0)
+         log_pass = 1;
+      else if (strcmp(arg, "--fresh") == 0)
+      {
+         memset(gpc_error, 0, sizeof gpc_error);
+         memset(gpc_error_via_linear, 0, sizeof gpc_error_via_linear);
+      }
+      else if (strcmp(arg, "--file") == 0)
+#        ifdef PNG_STDIO_SUPPORTED
+            opts |= USE_FILE;
+#        else
+            return SKIP; /* skipped: no support */
+#        endif
+      else if (strcmp(arg, "--memory") == 0)
+         opts &= ~USE_FILE;
+      else if (strcmp(arg, "--stdio") == 0)
+#        ifdef PNG_STDIO_SUPPORTED
+            opts |= USE_STDIO;
+#        else
+            return SKIP; /* skipped: no support */
+#        endif
+      else if (strcmp(arg, "--name") == 0)
+         opts &= ~USE_STDIO;
+      else if (strcmp(arg, "--verbose") == 0)
+         opts |= VERBOSE;
+      else if (strcmp(arg, "--quiet") == 0)
+         opts &= ~VERBOSE;
+      else if (strcmp(arg, "--preserve") == 0)
+         opts |= KEEP_TMPFILES;
+      else if (strcmp(arg, "--nopreserve") == 0)
+         opts &= ~KEEP_TMPFILES;
+      else if (strcmp(arg, "--keep-going") == 0)
+         opts |= KEEP_GOING;
+      else if (strcmp(arg, "--fast") == 0)
+         opts |= FAST_WRITE;
+      else if (strcmp(arg, "--slow") == 0)
+         opts &= ~FAST_WRITE;
+      else if (strcmp(arg, "--accumulate") == 0)
+         opts |= ACCUMULATE;
+      else if (strcmp(arg, "--redundant") == 0)
+         redundant = 1;
+      else if (strcmp(arg, "--stop") == 0)
+         opts &= ~KEEP_GOING;
+      else if (strcmp(arg, "--strict") == 0)
+         opts |= STRICT;
+      else if (strcmp(arg, "--nostrict") == 0)
+         opts &= ~STRICT;
+      else if (strcmp(arg, "--sRGB-16bit") == 0)
+         opts |= sRGB_16BIT;
+      else if (strcmp(arg, "--linear-16bit") == 0)
+         opts &= ~sRGB_16BIT;
+      else if (strcmp(arg, "--noreseed") == 0)
+         opts |= NO_RESEED;
+      else if (strcmp(arg, "--fault-gbg-warning") == 0)
+         opts |= GBG_ERROR;
+      else if (strcmp(arg, "--tmpfile") == 0)
+      {
+         if (c+1 < argc)
+         {
+            if (strlen(argv[++c]) >= sizeof tmpf)
+            {
+               fflush(stdout);
+               fprintf(stderr, "%s: %s is too long for a temp file prefix\n",
+                  argv[0], argv[c]);
+               exit(99);
+            }
+
+            /* Safe: checked above */
+            strncpy(tmpf, argv[c], sizeof (tmpf)-1);
+         }
+
+         else
+         {
+            fflush(stdout);
+            fprintf(stderr, "%s: %s requires a temporary file prefix\n",
+               argv[0], arg);
+            exit(99);
+         }
+      }
+      else if (strcmp(arg, "--touch") == 0)
+      {
+         if (c+1 < argc)
+            touch = argv[++c];
+
+         else
+         {
+            fflush(stdout);
+            fprintf(stderr, "%s: %s requires a file name argument\n",
+               argv[0], arg);
+            exit(99);
+         }
+      }
+      else if (arg[0] == '+')
+      {
+         png_uint_32 format = formatof(arg+1);
+
+         if (format > FORMAT_COUNT)
+            exit(99);
+
+         format_set(&formats, format);
+      }
+      else if (arg[0] == '-' && arg[1] != 0 && (arg[1] != '0' || arg[2] != 0))
+      {
+         fflush(stdout);
+         fprintf(stderr, "%s: unknown option: %s\n", argv[0], arg);
+         exit(99);
+      }
+      else
+      {
+         if (format_is_initial(&formats))
+            format_default(&formats, redundant);
+
+         if (arg[0] == '-')
+         {
+            int term = (arg[1] == '0' ? 0 : '\n');
+            unsigned int ich = 0;
+
+            /* Loop reading files, use a static buffer to simplify this and just
+             * stop if the name gets to long.
+             */
+            static char buffer[4096];
+
+            do
+            {
+               int ch = getchar();
+
+               /* Don't allow '\0' in file names, and terminate with '\n' or,
+                * for -0, just '\0' (use -print0 to find to make this work!)
+                */
+               if (ch == EOF || ch == term || ch == 0)
+               {
+                  buffer[ich] = 0;
+
+                  if (ich > 0 && !test_one_file(buffer, &formats, opts,
+                     stride_extra, log_pass))
+                     retval = 1;
+
+                  if (ch == EOF)
+                     break;
+
+                  ich = 0;
+                  --ich; /* so that the increment below sets it to 0 again */
+               }
+
+               else
+                  buffer[ich] = (char)ch;
+            } while (++ich < sizeof buffer);
+
+            if (ich)
+            {
+               buffer[32] = 0;
+               buffer[4095] = 0;
+               fprintf(stderr, "%s...%s: file name too long\n", buffer,
+                  buffer+(4096-32));
+               exit(99);
+            }
+         }
+
+         else if (!test_one_file(arg, &formats, opts, stride_extra, log_pass))
+            retval = 1;
+      }
+   }
+
+   if (opts & ACCUMULATE)
+   {
+      unsigned int in;
+
+      printf("/* contrib/libtests/pngstest-errors.h\n");
+      printf(" *\n");
+      printf(" * BUILT USING:" PNG_HEADER_VERSION_STRING);
+      printf(" *\n");
+      printf(" * This code is released under the libpng license.\n");
+      printf(" * For conditions of distribution and use, see the disclaimer\n");
+      printf(" * and license in png.h\n");
+      printf(" *\n");
+      printf(" * THIS IS A MACHINE GENERATED FILE: do not edit it directly!\n");
+      printf(" * Instead run:\n");
+      printf(" *\n");
+      printf(" *    pngstest --accumulate\n");
+      printf(" *\n");
+      printf(" * on as many PNG files as possible; at least PNGSuite and\n");
+      printf(" * contrib/libtests/testpngs.\n");
+      printf(" */\n");
+
+      printf("static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =\n");
+      printf("{\n");
+      for (in=0; in<16; ++in)
+      {
+         unsigned int out;
+         printf(" { /* input: %s */\n ", format_names[in]);
+         for (out=0; out<16; ++out)
+         {
+            unsigned int alpha;
+            printf(" {");
+            for (alpha=0; alpha<4; ++alpha)
+            {
+               printf(" %d", gpc_error[in][out][alpha]);
+               if (alpha < 3) putchar(',');
+            }
+            printf(" }");
+            if (out < 15)
+            {
+               putchar(',');
+               if (out % 4 == 3) printf("\n ");
+            }
+         }
+         printf("\n }");
+
+         if (in < 15)
+            putchar(',');
+         else
+            putchar('\n');
+      }
+      printf("};\n");
+
+      printf("static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =\n");
+      printf("{\n");
+      for (in=0; in<16; ++in)
+      {
+         unsigned int out;
+         printf(" { /* input: %s */\n ", format_names[in]);
+         for (out=0; out<4; ++out)
+         {
+            unsigned int alpha;
+            printf(" {");
+            for (alpha=0; alpha<4; ++alpha)
+            {
+               printf(" %d", gpc_error_via_linear[in][out][alpha]);
+               if (alpha < 3) putchar(',');
+            }
+            printf(" }");
+            if (out < 3)
+               putchar(',');
+         }
+         printf("\n }");
+
+         if (in < 15)
+            putchar(',');
+         else
+            putchar('\n');
+      }
+      printf("};\n");
+
+      printf("static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =\n");
+      printf("{\n");
+      for (in=0; in<8; ++in)
+      {
+         unsigned int out;
+         printf(" { /* input: %s */\n ", format_names[in]);
+         for (out=0; out<8; ++out)
+         {
+            unsigned int alpha;
+            printf(" {");
+            for (alpha=0; alpha<4; ++alpha)
+            {
+               printf(" %d", gpc_error_to_colormap[in][out][alpha]);
+               if (alpha < 3) putchar(',');
+            }
+            printf(" }");
+            if (out < 7)
+            {
+               putchar(',');
+               if (out % 4 == 3) printf("\n ");
+            }
+         }
+         printf("\n }");
+
+         if (in < 7)
+            putchar(',');
+         else
+            putchar('\n');
+      }
+      printf("};\n");
+      printf("/* END MACHINE GENERATED */\n");
+   }
+
+   if (retval == 0 && touch != NULL)
+   {
+      FILE *fsuccess = fopen(touch, "wt");
+
+      if (fsuccess != NULL)
+      {
+         int error = 0;
+         fprintf(fsuccess, "PNG simple API tests succeeded\n");
+         fflush(fsuccess);
+         error = ferror(fsuccess);
+
+         if (fclose(fsuccess) || error)
+         {
+            fflush(stdout);
+            fprintf(stderr, "%s: write failed\n", touch);
+            exit(99);
+         }
+      }
+
+      else
+      {
+         fflush(stdout);
+         fprintf(stderr, "%s: open failed\n", touch);
+         exit(99);
+      }
+   }
+
+   return retval;
+}
+
+#else /* !PNG_SIMPLIFIED_READ_SUPPORTED */
+int main(void)
+{
+   fprintf(stderr, "pngstest: no read support in libpng, test skipped\n");
+   /* So the test is skipped: */
+   return SKIP;
+}
+#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngunknown.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngunknown.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngunknown.c	(revision 107811)
@@ -0,0 +1,1305 @@
+
+/* pngunknown.c - test the read side unknown chunk handling
+ *
+ * Copyright (c) 2021 Cosmin Truta
+ * Copyright (c) 2015,2017 Glenn Randers-Pehrson
+ * Written by John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * NOTES:
+ *   This is a C program that is intended to be linked against libpng.  It
+ *   allows the libpng unknown handling code to be tested by interpreting
+ *   arguments to save or discard combinations of chunks.  The program is
+ *   currently just a minimal validation for the built-in libpng facilities.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <setjmp.h>
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+
+/* Since this program tests the ability to change the unknown chunk handling
+ * these must be defined:
+ */
+#if defined(PNG_SET_UNKNOWN_CHUNKS_SUPPORTED) &&\
+   defined(PNG_STDIO_SUPPORTED) &&\
+   defined(PNG_READ_SUPPORTED)
+
+/* One of these must be defined to allow us to find out what happened.  It is
+ * still useful to set unknown chunk handling without either of these in order
+ * to cause *known* chunks to be discarded.  This can be a significant
+ * efficiency gain, but it can't really be tested here.
+ */
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED) ||\
+   defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+
+#if PNG_LIBPNG_VER < 10500
+/* This deliberately lacks the const. */
+typedef png_byte *png_const_bytep;
+
+/* This is copied from 1.5.1 png.h: */
+#define PNG_INTERLACE_ADAM7_PASSES 7
+#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
+#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
+#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
+#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
+   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
+#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
+   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
+#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
+   (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
+#define PNG_COL_FROM_PASS_COL(xIn, pass) \
+   (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
+#define PNG_PASS_MASK(pass,off) ( \
+   ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
+   ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
+#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
+   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
+#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
+   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
+
+/* These are needed too for the default build: */
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+
+/* This comes from pnglibconf.h after 1.5: */
+#define PNG_FP_1 100000
+#define PNG_GAMMA_THRESHOLD_FIXED\
+   ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
+#endif
+
+#if PNG_LIBPNG_VER < 10600
+   /* 1.6.0 constifies many APIs. The following exists to allow pngvalid to be
+    * compiled against earlier versions.
+    */
+#  define png_const_structp png_structp
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+   /* Copied from libpng 1.7.0 png.h */
+#define PNG_u2(b1, b2) (((unsigned int)(b1) << 8) + (b2))
+
+#define PNG_U16(b1, b2) ((png_uint_16)PNG_u2(b1, b2))
+#define PNG_U32(b1, b2, b3, b4)\
+   (((png_uint_32)PNG_u2(b1, b2) << 16) + PNG_u2(b3, b4))
+
+/* Constants for known chunk types.
+ */
+#define png_IDAT PNG_U32( 73,  68,  65,  84)
+#define png_IEND PNG_U32( 73,  69,  78,  68)
+#define png_IHDR PNG_U32( 73,  72,  68,  82)
+#define png_PLTE PNG_U32( 80,  76,  84,  69)
+#define png_bKGD PNG_U32( 98,  75,  71,  68)
+#define png_cHRM PNG_U32( 99,  72,  82,  77)
+#define png_eXIf PNG_U32(101,  88,  73, 102) /* registered July 2017 */
+#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
+#define png_gAMA PNG_U32(103,  65,  77,  65)
+#define png_gIFg PNG_U32(103,  73,  70, 103)
+#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
+#define png_gIFx PNG_U32(103,  73,  70, 120)
+#define png_hIST PNG_U32(104,  73,  83,  84)
+#define png_iCCP PNG_U32(105,  67,  67,  80)
+#define png_iTXt PNG_U32(105,  84,  88, 116)
+#define png_oFFs PNG_U32(111,  70,  70, 115)
+#define png_pCAL PNG_U32(112,  67,  65,  76)
+#define png_pHYs PNG_U32(112,  72,  89, 115)
+#define png_sBIT PNG_U32(115,  66,  73,  84)
+#define png_sCAL PNG_U32(115,  67,  65,  76)
+#define png_sPLT PNG_U32(115,  80,  76,  84)
+#define png_sRGB PNG_U32(115,  82,  71,  66)
+#define png_sTER PNG_U32(115,  84,  69,  82)
+#define png_tEXt PNG_U32(116,  69,  88, 116)
+#define png_tIME PNG_U32(116,  73,  77,  69)
+#define png_tRNS PNG_U32(116,  82,  78,  83)
+#define png_zTXt PNG_U32(122,  84,  88, 116)
+
+/* Test on flag values as defined in the spec (section 5.4): */
+#define PNG_CHUNK_ANCILLARY(c)    (1 & ((c) >> 29))
+#define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
+#define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
+#define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
+#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
+
+#endif /* PNG_LIBPNG_VER < 10700 */
+
+#ifdef __cplusplus
+#  define this not_the_cpp_this
+#  define new not_the_cpp_new
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+/* Unused formal parameter errors are removed using the following macro which is
+ * expected to have no bad effects on performance.
+ */
+#ifndef UNUSED
+#  if defined(__GNUC__) || defined(_MSC_VER)
+#     define UNUSED(param) (void)param;
+#  else
+#     define UNUSED(param)
+#  endif
+#endif
+
+/* Types of chunks not known to libpng */
+#define png_vpAg PNG_U32(118, 112, 65, 103)
+
+/* Chunk information */
+#define PNG_INFO_tEXt 0x10000000U
+#define PNG_INFO_iTXt 0x20000000U
+#define PNG_INFO_zTXt 0x40000000U
+
+#define PNG_INFO_sTER 0x01000000U
+#define PNG_INFO_vpAg 0x02000000U
+
+#define ABSENT  0
+#define START   1
+#define END     2
+
+static struct
+{
+   char        name[5];
+   png_uint_32 flag;
+   png_uint_32 tag;
+   int         unknown;    /* Chunk not known to libpng */
+   int         all;        /* Chunk set by the '-1' option */
+   int         position;   /* position in pngtest.png */
+   int         keep;       /* unknown handling setting */
+} chunk_info[] = {
+   /* Critical chunks */
+   { "IDAT", PNG_INFO_IDAT, png_IDAT, 0, 0,  START, 0 }, /* must be [0] */
+   { "PLTE", PNG_INFO_PLTE, png_PLTE, 0, 0, ABSENT, 0 },
+
+   /* Non-critical chunks that libpng handles */
+   /* This is a mess but it seems to be the only way to do it - there is no way
+    * to check for a definition outside a #if.
+    */
+   { "bKGD", PNG_INFO_bKGD, png_bKGD,
+#     ifdef PNG_READ_bKGD_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "cHRM", PNG_INFO_cHRM, png_cHRM,
+#     ifdef PNG_READ_cHRM_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "eXIf", PNG_INFO_eXIf, png_eXIf,
+#     ifdef PNG_READ_eXIf_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  END, 0 },
+   { "gAMA", PNG_INFO_gAMA, png_gAMA,
+#     ifdef PNG_READ_gAMA_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "hIST", PNG_INFO_hIST, png_hIST,
+#     ifdef PNG_READ_hIST_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1, ABSENT, 0 },
+   { "iCCP", PNG_INFO_iCCP, png_iCCP,
+#     ifdef PNG_READ_iCCP_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1, ABSENT, 0 },
+   { "iTXt", PNG_INFO_iTXt, png_iTXt,
+#     ifdef PNG_READ_iTXt_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1, ABSENT, 0 },
+   { "oFFs", PNG_INFO_oFFs, png_oFFs,
+#     ifdef PNG_READ_oFFs_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "pCAL", PNG_INFO_pCAL, png_pCAL,
+#     ifdef PNG_READ_pCAL_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "pHYs", PNG_INFO_pHYs, png_pHYs,
+#     ifdef PNG_READ_pHYs_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "sBIT", PNG_INFO_sBIT, png_sBIT,
+#     ifdef PNG_READ_sBIT_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "sCAL", PNG_INFO_sCAL, png_sCAL,
+#     ifdef PNG_READ_sCAL_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "sPLT", PNG_INFO_sPLT, png_sPLT,
+#     ifdef PNG_READ_sPLT_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1, ABSENT, 0 },
+   { "sRGB", PNG_INFO_sRGB, png_sRGB,
+#     ifdef PNG_READ_sRGB_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "tEXt", PNG_INFO_tEXt, png_tEXt,
+#     ifdef PNG_READ_tEXt_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "tIME", PNG_INFO_tIME, png_tIME,
+#     ifdef PNG_READ_tIME_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,  START, 0 },
+   { "tRNS", PNG_INFO_tRNS, png_tRNS,
+#     ifdef PNG_READ_tRNS_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      0, ABSENT, 0 },
+   { "zTXt", PNG_INFO_zTXt, png_zTXt,
+#     ifdef PNG_READ_zTXt_SUPPORTED
+         0,
+#     else
+         1,
+#     endif
+      1,    END, 0 },
+
+   /* No libpng handling */
+   { "sTER", PNG_INFO_sTER, png_sTER, 1, 1,  START, 0 },
+   { "vpAg", PNG_INFO_vpAg, png_vpAg, 1, 0,  START, 0 },
+};
+
+#define NINFO ((int)((sizeof chunk_info)/(sizeof chunk_info[0])))
+
+static void
+clear_keep(void)
+{
+   int i = NINFO;
+   while (--i >= 0)
+      chunk_info[i].keep = 0;
+}
+
+static int
+find(const char *name)
+{
+   int i = NINFO;
+   while (--i >= 0)
+   {
+      if (memcmp(chunk_info[i].name, name, 4) == 0)
+         break;
+   }
+
+   return i;
+}
+
+static int
+findb(const png_byte *name)
+{
+   int i = NINFO;
+   while (--i >= 0)
+   {
+      if (memcmp(chunk_info[i].name, name, 4) == 0)
+         break;
+   }
+
+   return i;
+}
+
+static int
+find_by_flag(png_uint_32 flag)
+{
+   int i = NINFO;
+
+   while (--i >= 0)
+      if (chunk_info[i].flag == flag)
+         return i;
+
+   fprintf(stderr, "pngunknown: internal error\n");
+   exit(4);
+}
+
+static int
+ancillary(const char *name)
+{
+   return PNG_CHUNK_ANCILLARY(PNG_U32(name[0], name[1], name[2], name[3]));
+}
+
+#ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+static int
+ancillaryb(const png_byte *name)
+{
+   return PNG_CHUNK_ANCILLARY(PNG_U32(name[0], name[1], name[2], name[3]));
+}
+#endif
+
+/* Type of an error_ptr */
+typedef struct
+{
+   jmp_buf     error_return;
+   png_structp png_ptr;
+   png_infop   info_ptr, end_ptr;
+   png_uint_32 before_IDAT;
+   png_uint_32 after_IDAT;
+   int         error_count;
+   int         warning_count;
+   int         keep; /* the default value */
+   const char *program;
+   const char *file;
+   const char *test;
+} display;
+
+static const char init[] = "initialization";
+static const char cmd[] = "command line";
+
+static void
+init_display(display *d, const char *program)
+{
+   memset(d, 0, sizeof *d);
+   d->png_ptr = NULL;
+   d->info_ptr = d->end_ptr = NULL;
+   d->error_count = d->warning_count = 0;
+   d->program = program;
+   d->file = program;
+   d->test = init;
+}
+
+static void
+clean_display(display *d)
+{
+   png_destroy_read_struct(&d->png_ptr, &d->info_ptr, &d->end_ptr);
+
+   /* This must not happen - it might cause an app crash */
+   if (d->png_ptr != NULL || d->info_ptr != NULL || d->end_ptr != NULL)
+   {
+      fprintf(stderr, "%s(%s): png_destroy_read_struct error\n", d->file,
+         d->test);
+      exit(1);
+   }
+}
+
+PNG_FUNCTION(void, display_exit, (display *d), static PNG_NORETURN)
+{
+   ++(d->error_count);
+
+   if (d->png_ptr != NULL)
+      clean_display(d);
+
+   /* During initialization and if this is a single command line argument set
+    * exit now - there is only one test, otherwise longjmp to do the next test.
+    */
+   if (d->test == init || d->test == cmd)
+      exit(1);
+
+   longjmp(d->error_return, 1);
+}
+
+static int
+display_rc(const display *d, int strict)
+{
+   return d->error_count + (strict ? d->warning_count : 0);
+}
+
+/* libpng error and warning callbacks */
+PNG_FUNCTION(void, (PNGCBAPI error), (png_structp png_ptr, const char *message),
+   static PNG_NORETURN)
+{
+   display *d = (display*)png_get_error_ptr(png_ptr);
+
+   fprintf(stderr, "%s(%s): libpng error: %s\n", d->file, d->test, message);
+   display_exit(d);
+}
+
+static void PNGCBAPI
+warning(png_structp png_ptr, const char *message)
+{
+   display *d = (display*)png_get_error_ptr(png_ptr);
+
+   fprintf(stderr, "%s(%s): libpng warning: %s\n", d->file, d->test, message);
+   ++(d->warning_count);
+}
+
+static png_uint_32
+get_valid(display *d, png_infop info_ptr)
+{
+   png_uint_32 flags = png_get_valid(d->png_ptr, info_ptr, (png_uint_32)~0);
+
+   /* Map the text chunks back into the flags */
+   {
+      png_textp text;
+      png_uint_32 ntext = png_get_text(d->png_ptr, info_ptr, &text, NULL);
+
+      while (ntext > 0) switch (text[--ntext].compression)
+      {
+         case -1:
+            flags |= PNG_INFO_tEXt;
+            break;
+         case 0:
+            flags |= PNG_INFO_zTXt;
+            break;
+         case 1:
+         case 2:
+            flags |= PNG_INFO_iTXt;
+            break;
+         default:
+            fprintf(stderr, "%s(%s): unknown text compression %d\n", d->file,
+               d->test, text[ntext].compression);
+            display_exit(d);
+      }
+   }
+
+   return flags;
+}
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+static int PNGCBAPI
+read_callback(png_structp pp, png_unknown_chunkp pc)
+{
+   /* This function mimics the behavior of png_set_keep_unknown_chunks by
+    * returning '0' to keep the chunk and '1' to discard it.
+    */
+   display *d = voidcast(display*, png_get_user_chunk_ptr(pp));
+   int chunk = findb(pc->name);
+   int keep, discard;
+
+   if (chunk < 0) /* not one in our list, so not a known chunk */
+      keep = d->keep;
+
+   else
+   {
+      keep = chunk_info[chunk].keep;
+      if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+      {
+         /* See the comments in png.h - use the default for unknown chunks,
+          * do not keep known chunks.
+          */
+         if (chunk_info[chunk].unknown)
+            keep = d->keep;
+
+         else
+            keep = PNG_HANDLE_CHUNK_NEVER;
+      }
+   }
+
+   switch (keep)
+   {
+      default:
+         fprintf(stderr, "%s(%s): %d: unrecognized chunk option\n", d->file,
+            d->test, chunk_info[chunk].keep);
+         display_exit(d);
+
+      case PNG_HANDLE_CHUNK_AS_DEFAULT:
+      case PNG_HANDLE_CHUNK_NEVER:
+         discard = 1; /*handled; discard*/
+         break;
+
+      case PNG_HANDLE_CHUNK_IF_SAFE:
+      case PNG_HANDLE_CHUNK_ALWAYS:
+         discard = 0; /*not handled; keep*/
+         break;
+   }
+
+   /* Also store information about this chunk in the display, the relevant flag
+    * is set if the chunk is to be kept ('not handled'.)
+    */
+   if (chunk >= 0)
+   {
+      if (!discard) /* stupidity to stop a GCC warning */
+      {
+         png_uint_32 flag = chunk_info[chunk].flag;
+
+         if (pc->location & PNG_AFTER_IDAT)
+            d->after_IDAT |= flag;
+
+         else
+            d->before_IDAT |= flag;
+      }
+   }
+
+   /* However if there is no support to store unknown chunks don't ask libpng to
+    * do it; there will be an png_error.
+    */
+#  ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+      return discard;
+#  else
+      return 1; /*handled; discard*/
+#  endif
+}
+#endif /* READ_USER_CHUNKS_SUPPORTED */
+
+#ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+static png_uint_32
+get_unknown(display *d, png_infop info_ptr, int after_IDAT)
+{
+   /* Create corresponding 'unknown' flags */
+   png_uint_32 flags = 0;
+
+   UNUSED(after_IDAT)
+
+   {
+      png_unknown_chunkp unknown;
+      int num_unknown = png_get_unknown_chunks(d->png_ptr, info_ptr, &unknown);
+
+      while (--num_unknown >= 0)
+      {
+         int chunk = findb(unknown[num_unknown].name);
+
+         /* Chunks not known to pngunknown must be validated here; since they
+          * must also be unknown to libpng the 'display->keep' behavior should
+          * have been used.
+          */
+         if (chunk < 0) switch (d->keep)
+         {
+            default: /* impossible */
+            case PNG_HANDLE_CHUNK_AS_DEFAULT:
+            case PNG_HANDLE_CHUNK_NEVER:
+               fprintf(stderr, "%s(%s): %s: %s: unknown chunk saved\n",
+                  d->file, d->test, d->keep ? "discard" : "default",
+                  unknown[num_unknown].name);
+               ++(d->error_count);
+               break;
+
+            case PNG_HANDLE_CHUNK_IF_SAFE:
+               if (!ancillaryb(unknown[num_unknown].name))
+               {
+                  fprintf(stderr,
+                     "%s(%s): if-safe: %s: unknown critical chunk saved\n",
+                     d->file, d->test, unknown[num_unknown].name);
+                  ++(d->error_count);
+                  break;
+               }
+               /* FALLTHROUGH */ /* (safe) */
+            case PNG_HANDLE_CHUNK_ALWAYS:
+               break;
+         }
+
+         else
+            flags |= chunk_info[chunk].flag;
+      }
+   }
+
+   return flags;
+}
+#else /* SAVE_UNKNOWN_CHUNKS */
+static png_uint_32
+get_unknown(display *d, png_infop info_ptr, int after_IDAT)
+   /* Otherwise this will return the cached values set by any user callback */
+{
+   UNUSED(info_ptr);
+
+   if (after_IDAT)
+      return d->after_IDAT;
+
+   else
+      return d->before_IDAT;
+}
+
+#  ifndef PNG_READ_USER_CHUNKS_SUPPORTED
+      /* The #defines above should mean this is never reached, it's just here as
+       * a check to ensure the logic is correct.
+       */
+#     error No store support and no user chunk support, this will not work
+#  endif /* READ_USER_CHUNKS */
+#endif /* SAVE_UNKNOWN_CHUNKS */
+
+static int
+check(FILE *fp, int argc, const char **argv, png_uint_32p flags/*out*/,
+   display *d, int set_callback)
+{
+   int i, npasses, ipass;
+   png_uint_32 height;
+
+   d->keep = PNG_HANDLE_CHUNK_AS_DEFAULT;
+   d->before_IDAT = 0;
+   d->after_IDAT = 0;
+
+   /* Some of these errors are permanently fatal and cause an exit here, others
+    * are per-test and cause an error return.
+    */
+   d->png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, d, error,
+      warning);
+   if (d->png_ptr == NULL)
+   {
+      fprintf(stderr, "%s(%s): could not allocate png struct\n", d->file,
+         d->test);
+      /* Terminate here, this error is not test specific. */
+      exit(1);
+   }
+
+   d->info_ptr = png_create_info_struct(d->png_ptr);
+   d->end_ptr = png_create_info_struct(d->png_ptr);
+   if (d->info_ptr == NULL || d->end_ptr == NULL)
+   {
+      fprintf(stderr, "%s(%s): could not allocate png info\n", d->file,
+         d->test);
+      clean_display(d);
+      exit(1);
+   }
+
+   png_init_io(d->png_ptr, fp);
+
+#  ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+      /* This is only done if requested by the caller; it interferes with the
+       * standard store/save mechanism.
+       */
+      if (set_callback)
+         png_set_read_user_chunk_fn(d->png_ptr, d, read_callback);
+#  else
+      UNUSED(set_callback)
+#  endif
+
+   /* Handle each argument in turn; multiple settings are possible for the same
+    * chunk and multiple calls will occur (the last one should override all
+    * preceding ones).
+    */
+   for (i=0; i<argc; ++i)
+   {
+      const char *equals = strchr(argv[i], '=');
+
+      if (equals != NULL)
+      {
+         int chunk, option;
+
+         if (strcmp(equals+1, "default") == 0)
+            option = PNG_HANDLE_CHUNK_AS_DEFAULT;
+         else if (strcmp(equals+1, "discard") == 0)
+            option = PNG_HANDLE_CHUNK_NEVER;
+         else if (strcmp(equals+1, "if-safe") == 0)
+            option = PNG_HANDLE_CHUNK_IF_SAFE;
+         else if (strcmp(equals+1, "save") == 0)
+            option = PNG_HANDLE_CHUNK_ALWAYS;
+         else
+         {
+            fprintf(stderr, "%s(%s): %s: unrecognized chunk option\n", d->file,
+               d->test, argv[i]);
+            display_exit(d);
+         }
+
+         switch (equals - argv[i])
+         {
+            case 4: /* chunk name */
+               chunk = find(argv[i]);
+
+               if (chunk >= 0)
+               {
+                  /* These #if tests have the effect of skipping the arguments
+                   * if SAVE support is unavailable - we can't do a useful test
+                   * in this case, so we just check the arguments!  This could
+                   * be improved in the future by using the read callback.
+                   */
+#                 if PNG_LIBPNG_VER >= 10700 &&\
+                     !defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+                     if (option < PNG_HANDLE_CHUNK_IF_SAFE)
+#                 endif /* 1.7+ SAVE_UNKNOWN_CHUNKS */
+                  {
+                     png_byte name[5];
+
+                     memcpy(name, chunk_info[chunk].name, 5);
+                     png_set_keep_unknown_chunks(d->png_ptr, option, name, 1);
+                     chunk_info[chunk].keep = option;
+                  }
+                  continue;
+               }
+
+               break;
+
+            case 7: /* default */
+               if (memcmp(argv[i], "default", 7) == 0)
+               {
+#                 if PNG_LIBPNG_VER >= 10700 &&\
+                     !defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+                     if (option < PNG_HANDLE_CHUNK_IF_SAFE)
+#                 endif /* 1.7+ SAVE_UNKNOWN_CHUNKS */
+                     png_set_keep_unknown_chunks(d->png_ptr, option, NULL, 0);
+
+                  d->keep = option;
+                  continue;
+               }
+
+               break;
+
+            case 3: /* all */
+               if (memcmp(argv[i], "all", 3) == 0)
+               {
+#                 if PNG_LIBPNG_VER >= 10700 &&\
+                     !defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
+                     if (option < PNG_HANDLE_CHUNK_IF_SAFE)
+#                 endif /* 1.7+ SAVE_UNKNOWN_CHUNKS */
+                     png_set_keep_unknown_chunks(d->png_ptr, option, NULL, -1);
+
+                  d->keep = option;
+
+                  for (chunk = 0; chunk < NINFO; ++chunk)
+                     if (chunk_info[chunk].all)
+                        chunk_info[chunk].keep = option;
+                  continue;
+               }
+
+               break;
+
+            default: /* some misplaced = */
+
+               break;
+         }
+      }
+
+      fprintf(stderr, "%s(%s): %s: unrecognized chunk argument\n", d->file,
+         d->test, argv[i]);
+      display_exit(d);
+   }
+
+   png_read_info(d->png_ptr, d->info_ptr);
+
+   switch (png_get_interlace_type(d->png_ptr, d->info_ptr))
+   {
+      case PNG_INTERLACE_NONE:
+         npasses = 1;
+         break;
+
+      case PNG_INTERLACE_ADAM7:
+         npasses = PNG_INTERLACE_ADAM7_PASSES;
+         break;
+
+      default:
+         /* Hard error because it is not test specific */
+         fprintf(stderr, "%s(%s): invalid interlace type\n", d->file, d->test);
+         clean_display(d);
+         exit(1);
+   }
+
+   /* Skip the image data, if IDAT is not being handled then don't do this
+    * because it will cause a CRC error.
+    */
+   if (chunk_info[0/*IDAT*/].keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+   {
+      png_start_read_image(d->png_ptr);
+      height = png_get_image_height(d->png_ptr, d->info_ptr);
+
+      if (npasses > 1)
+      {
+         png_uint_32 width = png_get_image_width(d->png_ptr, d->info_ptr);
+
+         for (ipass=0; ipass<npasses; ++ipass)
+         {
+            png_uint_32 wPass = PNG_PASS_COLS(width, ipass);
+
+            if (wPass > 0)
+            {
+               png_uint_32 y;
+
+               for (y=0; y<height; ++y)
+                  if (PNG_ROW_IN_INTERLACE_PASS(y, ipass))
+                     png_read_row(d->png_ptr, NULL, NULL);
+            }
+         }
+      } /* interlaced */
+
+      else /* not interlaced */
+      {
+         png_uint_32 y;
+
+         for (y=0; y<height; ++y)
+            png_read_row(d->png_ptr, NULL, NULL);
+      }
+   }
+
+   png_read_end(d->png_ptr, d->end_ptr);
+
+   flags[0] = get_valid(d, d->info_ptr);
+   flags[1] = get_unknown(d, d->info_ptr, 0/*before IDAT*/);
+
+   /* Only png_read_png sets PNG_INFO_IDAT! */
+   flags[chunk_info[0/*IDAT*/].keep != PNG_HANDLE_CHUNK_AS_DEFAULT] |=
+      PNG_INFO_IDAT;
+
+   flags[2] = get_valid(d, d->end_ptr);
+   flags[3] = get_unknown(d, d->end_ptr, 1/*after IDAT*/);
+
+   clean_display(d);
+
+   return d->keep;
+}
+
+static void
+check_error(display *d, png_uint_32 flags, const char *message)
+{
+   while (flags)
+   {
+      png_uint_32 flag = flags & -(png_int_32)flags;
+      int i = find_by_flag(flag);
+
+      fprintf(stderr, "%s(%s): chunk %s: %s\n", d->file, d->test,
+         chunk_info[i].name, message);
+      ++(d->error_count);
+
+      flags &= ~flag;
+   }
+}
+
+static void
+check_handling(display *d, int def, png_uint_32 chunks, png_uint_32 known,
+   png_uint_32 unknown, const char *position, int set_callback)
+{
+   while (chunks)
+   {
+      png_uint_32 flag = chunks & -(png_int_32)chunks;
+      int i = find_by_flag(flag);
+      int keep = chunk_info[i].keep;
+      const char *type;
+      const char *errorx = NULL;
+
+      if (chunk_info[i].unknown)
+      {
+         if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+         {
+            type = "UNKNOWN (default)";
+            keep = def;
+         }
+
+         else
+            type = "UNKNOWN (specified)";
+
+         if (flag & known)
+            errorx = "chunk processed";
+
+         else switch (keep)
+         {
+            case PNG_HANDLE_CHUNK_AS_DEFAULT:
+               if (flag & unknown)
+                  errorx = "DEFAULT: unknown chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_NEVER:
+               if (flag & unknown)
+                  errorx = "DISCARD: unknown chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_IF_SAFE:
+               if (ancillary(chunk_info[i].name))
+               {
+                  if (!(flag & unknown))
+                     errorx = "IF-SAFE: unknown ancillary chunk lost";
+               }
+
+               else if (flag & unknown)
+                  errorx = "IF-SAFE: unknown critical chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_ALWAYS:
+               if (!(flag & unknown))
+                  errorx = "SAVE: unknown chunk lost";
+               break;
+
+            default:
+               errorx = "internal error: bad keep";
+               break;
+         }
+      } /* unknown chunk */
+
+      else /* known chunk */
+      {
+         type = "KNOWN";
+
+         if (flag & known)
+         {
+            /* chunk was processed, it won't have been saved because that is
+             * caught below when checking for inconsistent processing.
+             */
+            if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
+               errorx = "!DEFAULT: known chunk processed";
+         }
+
+         else /* not processed */ switch (keep)
+         {
+            case PNG_HANDLE_CHUNK_AS_DEFAULT:
+               errorx = "DEFAULT: known chunk not processed";
+               break;
+
+            case PNG_HANDLE_CHUNK_NEVER:
+               if (flag & unknown)
+                  errorx = "DISCARD: known chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_IF_SAFE:
+               if (ancillary(chunk_info[i].name))
+               {
+                  if (!(flag & unknown))
+                     errorx = "IF-SAFE: known ancillary chunk lost";
+               }
+
+               else if (flag & unknown)
+                  errorx = "IF-SAFE: known critical chunk saved";
+               break;
+
+            case PNG_HANDLE_CHUNK_ALWAYS:
+               if (!(flag & unknown))
+                  errorx = "SAVE: known chunk lost";
+               break;
+
+            default:
+               errorx = "internal error: bad keep (2)";
+               break;
+         }
+      }
+
+      if (errorx != NULL)
+      {
+         ++(d->error_count);
+         fprintf(stderr, "%s(%s%s): %s %s %s: %s\n", d->file, d->test,
+            set_callback ? ",callback" : "",
+            type, chunk_info[i].name, position, errorx);
+      }
+
+      chunks &= ~flag;
+   }
+}
+
+static void
+perform_one_test(FILE *fp, int argc, const char **argv,
+   png_uint_32 *default_flags, display *d, int set_callback)
+{
+   int def;
+   png_uint_32 flags[2][4];
+
+   rewind(fp);
+   clear_keep();
+   memcpy(flags[0], default_flags, sizeof flags[0]);
+
+   def = check(fp, argc, argv, flags[1], d, set_callback);
+
+   /* If IDAT is being handled as unknown the image read is skipped and all the
+    * IDATs after the first end up in the end info struct, so in this case add
+    * IDAT to the list of unknowns.  (Do this after 'check' above sets the
+    * chunk_info 'keep' fields.)
+    *
+    * Note that the flag setting has to be in the 'known' field to avoid
+    * triggering the consistency check below and the flag must only be set if
+    * there are multiple IDATs, so if the check above did find an unknown IDAT
+    * after IDAT.
+    */
+   if (chunk_info[0/*IDAT*/].keep != PNG_HANDLE_CHUNK_AS_DEFAULT &&
+       (flags[1][3] & PNG_INFO_IDAT) != 0)
+      flags[0][2] |= PNG_INFO_IDAT;
+
+   /* Chunks should either be known or unknown, never both and this should apply
+    * whether the chunk is before or after the IDAT (actually, the app can
+    * probably change this by swapping the handling after the image, but this
+    * test does not do that.)
+    */
+   check_error(d, (flags[0][0]|flags[0][2]) & (flags[0][1]|flags[0][3]),
+      "chunk handled inconsistently in count tests");
+   check_error(d, (flags[1][0]|flags[1][2]) & (flags[1][1]|flags[1][3]),
+      "chunk handled inconsistently in option tests");
+
+   /* Now find out what happened to each chunk before and after the IDAT and
+    * determine if the behavior was correct.  First some basic sanity checks,
+    * any known chunk should be known in the original count, any unknown chunk
+    * should be either known or unknown in the original.
+    */
+   {
+      png_uint_32 test;
+
+      test = flags[1][0] & ~flags[0][0];
+      check_error(d, test, "new known chunk before IDAT");
+      test = flags[1][1] & ~(flags[0][0] | flags[0][1]);
+      check_error(d, test, "new unknown chunk before IDAT");
+      test = flags[1][2] & ~flags[0][2];
+      check_error(d, test, "new known chunk after IDAT");
+      test = flags[1][3] & ~(flags[0][2] | flags[0][3]);
+      check_error(d, test, "new unknown chunk after IDAT");
+   }
+
+   /* Now each chunk in the original list should have been handled according to
+    * the options set for that chunk, regardless of whether libpng knows about
+    * it or not.
+    */
+   check_handling(d, def, flags[0][0] | flags[0][1], flags[1][0], flags[1][1],
+      "before IDAT", set_callback);
+   check_handling(d, def, flags[0][2] | flags[0][3], flags[1][2], flags[1][3],
+      "after IDAT", set_callback);
+}
+
+static void
+perform_one_test_safe(FILE *fp, int argc, const char **argv,
+   png_uint_32 *default_flags, display *d, const char *test)
+{
+   if (setjmp(d->error_return) == 0)
+   {
+      d->test = test; /* allow use of d->error_return */
+#     ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+         perform_one_test(fp, argc, argv, default_flags, d, 0);
+#     endif
+#     ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+         perform_one_test(fp, argc, argv, default_flags, d, 1);
+#     endif
+      d->test = init; /* prevent use of d->error_return */
+   }
+}
+
+static const char *standard_tests[] =
+{
+   "discard", "default=discard", NULL,
+   "save", "default=save", NULL,
+   "if-safe", "default=if-safe", NULL,
+   "vpAg", "vpAg=if-safe", NULL,
+   "sTER", "sTER=if-safe", NULL,
+   "IDAT", "default=discard", "IDAT=save", NULL,
+   "sAPI", "bKGD=save", "cHRM=save", "gAMA=save", "all=discard", "iCCP=save",
+      "sBIT=save", "sRGB=save", "eXIf=save", NULL,
+   NULL /*end*/
+};
+
+static PNG_NORETURN void
+usage(const char *program, const char *reason)
+{
+   fprintf(stderr, "pngunknown: %s: usage:\n %s [--strict] "
+      "--default|{(CHNK|default|all)=(default|discard|if-safe|save)} "
+      "testfile.png\n", reason, program);
+   exit(99);
+}
+
+int
+main(int argc, const char **argv)
+{
+   FILE *fp;
+   png_uint_32 default_flags[4]; /*valid,unknown{before,after}*/
+   int strict = 0, default_tests = 0;
+   const char *count_argv = "default=save";
+   const char *touch_file = NULL;
+   display d;
+
+   init_display(&d, argv[0]);
+
+   while (++argv, --argc > 0)
+   {
+      if (strcmp(*argv, "--strict") == 0)
+         strict = 1;
+
+      else if (strcmp(*argv, "--default") == 0)
+         default_tests = 1;
+
+      else if (strcmp(*argv, "--touch") == 0)
+      {
+         if (argc > 1)
+            touch_file = *++argv, --argc;
+
+         else
+            usage(d.program, "--touch: missing file name");
+      }
+
+      else
+         break;
+   }
+
+   /* A file name is required, but there should be no other arguments if
+    * --default was specified.
+    */
+   if (argc <= 0)
+      usage(d.program, "missing test file");
+
+   /* GCC BUG: if (default_tests && argc != 1) triggers some weird GCC argc
+    * optimization which causes warnings with -Wstrict-overflow!
+    */
+   else if (default_tests)
+      if (argc != 1)
+         usage(d.program, "extra arguments");
+
+   /* The name of the test file is the last argument; remove it. */
+   d.file = argv[--argc];
+
+   fp = fopen(d.file, "rb");
+   if (fp == NULL)
+   {
+      perror(d.file);
+      exit(99);
+   }
+
+   /* First find all the chunks, known and unknown, in the test file, a failure
+    * here aborts the whole test.
+    *
+    * If 'save' is supported then the normal saving method should happen,
+    * otherwise if 'read' is supported then the read callback will do the
+    * same thing.  If both are supported the 'read' callback won't be
+    * instantiated by default.  If 'save' is *not* supported then a user
+    * callback is required even though we can call png_get_unknown_chunks.
+    */
+   if (check(fp, 1, &count_argv, default_flags, &d,
+#     ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+         0
+#     else
+         1
+#     endif
+      ) != PNG_HANDLE_CHUNK_ALWAYS)
+   {
+      fprintf(stderr, "%s: %s: internal error\n", d.program, d.file);
+      exit(99);
+   }
+
+   /* Now find what the various supplied options cause to change: */
+   if (!default_tests)
+   {
+      d.test = cmd; /* acts as a flag to say exit, do not longjmp */
+#     ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+         perform_one_test(fp, argc, argv, default_flags, &d, 0);
+#     endif
+#     ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+         perform_one_test(fp, argc, argv, default_flags, &d, 1);
+#     endif
+      d.test = init;
+   }
+
+   else
+   {
+      const char **test = standard_tests;
+
+      /* Set the exit_test pointer here so we can continue after a libpng error.
+       * NOTE: this leaks memory because the png_struct data from the failing
+       * test is never freed.
+       */
+      while (*test)
+      {
+         const char *this_test = *test++;
+         const char **next = test;
+         int count = display_rc(&d, strict), new_count;
+         const char *result;
+         int arg_count = 0;
+
+         while (*next != NULL)
+         {
+            ++next;
+            ++arg_count;
+         }
+
+         perform_one_test_safe(fp, arg_count, test, default_flags, &d,
+            this_test);
+
+         new_count = display_rc(&d, strict);
+
+         if (new_count == count)
+            result = "PASS";
+
+         else
+            result = "FAIL";
+
+         printf("%s: %s %s\n", result, d.program, this_test);
+
+         test = next+1;
+      }
+   }
+
+   fclose(fp);
+
+   if (display_rc(&d, strict) == 0)
+   {
+      /* Success, touch the success file if appropriate */
+      if (touch_file != NULL)
+      {
+         FILE *fsuccess = fopen(touch_file, "wt");
+
+         if (fsuccess != NULL)
+         {
+            int err = 0;
+            fprintf(fsuccess, "PNG unknown tests succeeded\n");
+            fflush(fsuccess);
+            err = ferror(fsuccess);
+
+            if (fclose(fsuccess) || err)
+            {
+               fprintf(stderr, "%s: write failed\n", touch_file);
+               exit(99);
+            }
+         }
+
+         else
+         {
+            fprintf(stderr, "%s: open failed\n", touch_file);
+            exit(99);
+         }
+      }
+
+      return 0;
+   }
+
+   return 1;
+}
+
+#else /* !(READ_USER_CHUNKS || SAVE_UNKNOWN_CHUNKS) */
+int
+main(void)
+{
+   fprintf(stderr,
+      " test ignored: no support to find out about unknown chunks\n");
+   /* So the test is skipped: */
+   return SKIP;
+}
+#endif /* READ_USER_CHUNKS || SAVE_UNKNOWN_CHUNKS */
+
+#else /* !(SET_UNKNOWN_CHUNKS && READ) */
+int
+main(void)
+{
+   fprintf(stderr,
+      " test ignored: no support to modify unknown chunk handling\n");
+   /* So the test is skipped: */
+   return SKIP;
+}
+#endif /* SET_UNKNOWN_CHUNKS && READ*/
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngvalid.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngvalid.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/pngvalid.c	(revision 107811)
@@ -0,0 +1,12297 @@
+
+/* pngvalid.c - validate libpng by constructing then reading png files.
+ *
+ * Copyright (c) 2021 Cosmin Truta
+ * Copyright (c) 2014-2017 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * NOTES:
+ *   This is a C program that is intended to be linked against libpng.  It
+ *   generates bitmaps internally, stores them as PNG files (using the
+ *   sequential write code) then reads them back (using the sequential
+ *   read code) and validates that the result has the correct data.
+ *
+ *   The program can be modified and extended to test the correctness of
+ *   transformations performed by libpng.
+ */
+
+#define _POSIX_SOURCE 1
+#define _ISOC99_SOURCE 1 /* For floating point */
+#define _GNU_SOURCE 1 /* For the floating point exception extension */
+#define _BSD_SOURCE 1 /* For the floating point exception extension */
+#define _DEFAULT_SOURCE 1 /* For the floating point exception extension */
+
+#include <signal.h>
+#include <stdio.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+#ifdef HAVE_FEENABLEEXCEPT /* from config.h, if included */
+#  include <fenv.h>
+#endif
+
+#ifndef FE_DIVBYZERO
+#  define FE_DIVBYZERO 0
+#endif
+#ifndef FE_INVALID
+#  define FE_INVALID 0
+#endif
+#ifndef FE_OVERFLOW
+#  define FE_OVERFLOW 0
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#ifdef PNG_ZLIB_HEADER
+#  include PNG_ZLIB_HEADER
+#else
+#  include <zlib.h>   /* For crc32 */
+#endif
+
+/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
+ * a skipped test, in earlier versions we need to succeed on a skipped test, so:
+ */
+#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+/* pngvalid requires write support and one of the fixed or floating point APIs.
+ * progressive read is also required currently as the progressive read pointer
+ * is used to record the 'display' structure.
+ */
+#if defined PNG_WRITE_SUPPORTED &&\
+   (defined PNG_PROGRESSIVE_READ_SUPPORTED) &&\
+   (defined PNG_FIXED_POINT_SUPPORTED || defined PNG_FLOATING_POINT_SUPPORTED)
+
+#if PNG_LIBPNG_VER < 10500
+/* This deliberately lacks the const. */
+typedef png_byte *png_const_bytep;
+
+/* This is copied from 1.5.1 png.h: */
+#define PNG_INTERLACE_ADAM7_PASSES 7
+#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
+#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
+#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
+#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
+   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
+#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
+   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
+#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
+   (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
+#define PNG_COL_FROM_PASS_COL(xIn, pass) \
+   (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
+#define PNG_PASS_MASK(pass,off) ( \
+   ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
+   ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
+#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
+   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
+#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
+   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
+
+/* These are needed too for the default build: */
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+
+/* This comes from pnglibconf.h after 1.5: */
+#define PNG_FP_1 100000
+#define PNG_GAMMA_THRESHOLD_FIXED\
+   ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
+#endif
+
+#if PNG_LIBPNG_VER < 10600
+   /* 1.6.0 constifies many APIs, the following exists to allow pngvalid to be
+    * compiled against earlier versions.
+    */
+#  define png_const_structp png_structp
+#endif
+
+#ifndef RELEASE_BUILD
+   /* RELEASE_BUILD is true for releases and release candidates: */
+#  define RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
+#endif
+#if RELEASE_BUILD
+#   define debugonly(something)
+#else /* !RELEASE_BUILD */
+#   define debugonly(something) something
+#endif /* !RELEASE_BUILD */
+
+#include <float.h>  /* For floating point constants */
+#include <stdlib.h> /* For malloc */
+#include <string.h> /* For memcpy, memset */
+#include <math.h>   /* For floor */
+
+/* Convenience macros. */
+#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
+#define CHUNK_IHDR CHUNK(73,72,68,82)
+#define CHUNK_PLTE CHUNK(80,76,84,69)
+#define CHUNK_IDAT CHUNK(73,68,65,84)
+#define CHUNK_IEND CHUNK(73,69,78,68)
+#define CHUNK_cHRM CHUNK(99,72,82,77)
+#define CHUNK_gAMA CHUNK(103,65,77,65)
+#define CHUNK_sBIT CHUNK(115,66,73,84)
+#define CHUNK_sRGB CHUNK(115,82,71,66)
+
+/* Unused formal parameter errors are removed using the following macro which is
+ * expected to have no bad effects on performance.
+ */
+#ifndef UNUSED
+#  if defined(__GNUC__) || defined(_MSC_VER)
+#     define UNUSED(param) (void)param;
+#  else
+#     define UNUSED(param)
+#  endif
+#endif
+
+/***************************** EXCEPTION HANDLING *****************************/
+#ifdef PNG_FREESTANDING_TESTS
+#  include <cexcept.h>
+#else
+#  include "../visupng/cexcept.h"
+#endif
+
+#ifdef __cplusplus
+#  define this not_the_cpp_this
+#  define new not_the_cpp_new
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+struct png_store;
+define_exception_type(struct png_store*);
+
+/* The following are macros to reduce typing everywhere where the well known
+ * name 'the_exception_context' must be defined.
+ */
+#define anon_context(ps) struct exception_context *the_exception_context = \
+   &(ps)->exception_context
+#define context(ps,fault) anon_context(ps); png_store *fault
+
+/* This macro returns the number of elements in an array as an (unsigned int),
+ * it is necessary to avoid the inability of certain versions of GCC to use
+ * the value of a compile-time constant when performing range checks.  It must
+ * be passed an array name.
+ */
+#define ARRAY_SIZE(a) ((unsigned int)((sizeof (a))/(sizeof (a)[0])))
+
+/* GCC BUG 66447 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66447) requires
+ * some broken GCC versions to be fixed up to avoid invalid whining about auto
+ * variables that are *not* changed within the scope of a setjmp being changed.
+ *
+ * Feel free to extend the list of broken versions.
+ */
+#define is_gnu(major,minor)\
+   (defined __GNUC__) && __GNUC__ == (major) && __GNUC_MINOR__ == (minor)
+#define is_gnu_patch(major,minor,patch)\
+   is_gnu(major,minor) && __GNUC_PATCHLEVEL__ == 0
+/* For the moment just do it always; all versions of GCC seem to be broken: */
+#ifdef __GNUC__
+   const void * volatile make_volatile_for_gnu;
+#  define gnu_volatile(x) make_volatile_for_gnu = &x;
+#else /* !GNUC broken versions */
+#  define gnu_volatile(x)
+#endif /* !GNUC broken versions */
+
+/******************************* UTILITIES ************************************/
+/* Error handling is particularly problematic in production code - error
+ * handlers often themselves have bugs which lead to programs that detect
+ * minor errors crashing.  The following functions deal with one very
+ * common class of errors in error handlers - attempting to format error or
+ * warning messages into buffers that are too small.
+ */
+static size_t safecat(char *buffer, size_t bufsize, size_t pos,
+   const char *cat)
+{
+   while (pos < bufsize && cat != NULL && *cat != 0)
+      buffer[pos++] = *cat++;
+
+   if (pos >= bufsize)
+      pos = bufsize-1;
+
+   buffer[pos] = 0;
+   return pos;
+}
+
+static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
+{
+   char number[64];
+   sprintf(number, "%d", n);
+   return safecat(buffer, bufsize, pos, number);
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
+    int precision)
+{
+   char number[64];
+   sprintf(number, "%.*f", precision, d);
+   return safecat(buffer, bufsize, pos, number);
+}
+#endif
+
+static const char invalid[] = "invalid";
+static const char sep[] = ": ";
+
+static const char *colour_types[8] =
+{
+   "grayscale", invalid, "truecolour", "indexed-colour",
+   "grayscale with alpha", invalid, "truecolour with alpha", invalid
+};
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Convert a double precision value to fixed point. */
+static png_fixed_point
+fix(double d)
+{
+   d = floor(d * PNG_FP_1 + .5);
+   return (png_fixed_point)d;
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* Generate random bytes.  This uses a boring repeatable algorithm and it
+ * is implemented here so that it gives the same set of numbers on every
+ * architecture.  It's a linear congruential generator (Knuth or Sedgewick
+ * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
+ * Hill, "The Art of Electronics" (Pseudo-Random Bit Sequences and Noise
+ * Generation.)
+ */
+static void
+make_random_bytes(png_uint_32* seed, void* pv, size_t size)
+{
+   png_uint_32 u0 = seed[0], u1 = seed[1];
+   png_bytep bytes = voidcast(png_bytep, pv);
+
+   /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
+    * bit-20.  The top 1 bit is in u1, the bottom 32 are in u0.
+    */
+   size_t i;
+   for (i=0; i<size; ++i)
+   {
+      /* First generate 8 new bits then shift them in at the end. */
+      png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
+      u1 <<= 8;
+      u1 |= u0 >> 24;
+      u0 <<= 8;
+      u0 |= u;
+      *bytes++ = (png_byte)u;
+   }
+
+   seed[0] = u0;
+   seed[1] = u1;
+}
+
+static void
+make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
+{
+   make_random_bytes(seed, bytes, 4);
+}
+
+#if defined PNG_READ_SUPPORTED || defined PNG_WRITE_tRNS_SUPPORTED ||\
+    defined PNG_WRITE_FILTER_SUPPORTED
+static void
+randomize(void *pv, size_t size)
+{
+   static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
+   make_random_bytes(random_seed, pv, size);
+}
+
+#define R8(this) randomize(&(this), sizeof (this))
+
+#ifdef PNG_READ_SUPPORTED
+static png_byte
+random_byte(void)
+{
+   unsigned char b1[1];
+   randomize(b1, sizeof b1);
+   return b1[0];
+}
+#endif /* READ */
+
+static png_uint_16
+random_u16(void)
+{
+   unsigned char b2[2];
+   randomize(b2, sizeof b2);
+   return png_get_uint_16(b2);
+}
+
+#if defined PNG_READ_RGB_TO_GRAY_SUPPORTED ||\
+    defined PNG_READ_FILLER_SUPPORTED
+static png_uint_32
+random_u32(void)
+{
+   unsigned char b4[4];
+   randomize(b4, sizeof b4);
+   return png_get_uint_32(b4);
+}
+#endif /* READ_FILLER || READ_RGB_TO_GRAY */
+
+#endif /* READ || WRITE_tRNS || WRITE_FILTER */
+
+#if defined PNG_READ_TRANSFORMS_SUPPORTED ||\
+    defined PNG_WRITE_FILTER_SUPPORTED
+static unsigned int
+random_mod(unsigned int max)
+{
+   return random_u16() % max; /* 0 .. max-1 */
+}
+#endif /* READ_TRANSFORMS || WRITE_FILTER */
+
+#if (defined PNG_READ_RGB_TO_GRAY_SUPPORTED) ||\
+    (defined PNG_READ_FILLER_SUPPORTED)
+static int
+random_choice(void)
+{
+   return random_byte() & 1;
+}
+#endif /* READ_RGB_TO_GRAY || READ_FILLER */
+
+/* A numeric ID based on PNG file characteristics.  The 'do_interlace' field
+ * simply records whether pngvalid did the interlace itself or whether it
+ * was done by libpng.  Width and height must be less than 256.  'palette' is an
+ * index of the palette to use for formats with a palette otherwise a boolean
+ * indicating if a tRNS chunk was generated.
+ */
+#define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
+   ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
+    (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
+
+#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
+#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
+#define PALETTE_FROM_ID(id) (((id) >> 8) & 0x1f)
+#define INTERLACE_FROM_ID(id) ((png_byte)(((id) >> 13) & 0x3))
+#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
+#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
+#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
+
+/* Utility to construct a standard name for a standard image. */
+static size_t
+standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
+    int bit_depth, unsigned int npalette, int interlace_type,
+    png_uint_32 w, png_uint_32 h, int do_interlace)
+{
+   pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
+   if (colour_type == 3) /* must have a palette */
+   {
+      pos = safecat(buffer, bufsize, pos, "[");
+      pos = safecatn(buffer, bufsize, pos, npalette);
+      pos = safecat(buffer, bufsize, pos, "]");
+   }
+
+   else if (npalette != 0)
+      pos = safecat(buffer, bufsize, pos, "+tRNS");
+
+   pos = safecat(buffer, bufsize, pos, " ");
+   pos = safecatn(buffer, bufsize, pos, bit_depth);
+   pos = safecat(buffer, bufsize, pos, " bit");
+
+   if (interlace_type != PNG_INTERLACE_NONE)
+   {
+      pos = safecat(buffer, bufsize, pos, " interlaced");
+      if (do_interlace)
+         pos = safecat(buffer, bufsize, pos, "(pngvalid)");
+      else
+         pos = safecat(buffer, bufsize, pos, "(libpng)");
+   }
+
+   if (w > 0 || h > 0)
+   {
+      pos = safecat(buffer, bufsize, pos, " ");
+      pos = safecatn(buffer, bufsize, pos, w);
+      pos = safecat(buffer, bufsize, pos, "x");
+      pos = safecatn(buffer, bufsize, pos, h);
+   }
+
+   return pos;
+}
+
+static size_t
+standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
+{
+   return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
+      DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
+      WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
+}
+
+/* Convenience API and defines to list valid formats.  Note that 16 bit read and
+ * write support is required to do 16 bit read tests (we must be able to make a
+ * 16 bit image to test!)
+ */
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+#  define WRITE_BDHI 4
+#  ifdef PNG_READ_16BIT_SUPPORTED
+#     define READ_BDHI 4
+#     define DO_16BIT
+#  endif
+#else
+#  define WRITE_BDHI 3
+#endif
+#ifndef DO_16BIT
+#  define READ_BDHI 3
+#endif
+
+/* The following defines the number of different palettes to generate for
+ * each log bit depth of a colour type 3 standard image.
+ */
+#define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1U : 16U)
+
+static int
+next_format(png_bytep colour_type, png_bytep bit_depth,
+   unsigned int* palette_number, int low_depth_gray, int tRNS)
+{
+   if (*bit_depth == 0)
+   {
+      *colour_type = 0;
+      if (low_depth_gray)
+         *bit_depth = 1;
+      else
+         *bit_depth = 8;
+      *palette_number = 0;
+      return 1;
+   }
+
+   if  (*colour_type < 4/*no alpha channel*/)
+   {
+      /* Add multiple palettes for colour type 3, one image with tRNS
+       * and one without for other non-alpha formats:
+       */
+      unsigned int pn = ++*palette_number;
+      png_byte ct = *colour_type;
+
+      if (((ct == 0/*GRAY*/ || ct/*RGB*/ == 2) && tRNS && pn < 2) ||
+          (ct == 3/*PALETTE*/ && pn < PALETTE_COUNT(*bit_depth)))
+         return 1;
+
+      /* No: next bit depth */
+      *palette_number = 0;
+   }
+
+   *bit_depth = (png_byte)(*bit_depth << 1);
+
+   /* Palette images are restricted to 8 bit depth */
+   if (*bit_depth <= 8
+#ifdef DO_16BIT
+         || (*colour_type != 3 && *bit_depth <= 16)
+#endif
+      )
+      return 1;
+
+   /* Move to the next color type, or return 0 at the end. */
+   switch (*colour_type)
+   {
+      case 0:
+         *colour_type = 2;
+         *bit_depth = 8;
+         return 1;
+
+      case 2:
+         *colour_type = 3;
+         *bit_depth = 1;
+         return 1;
+
+      case 3:
+         *colour_type = 4;
+         *bit_depth = 8;
+         return 1;
+
+      case 4:
+         *colour_type = 6;
+         *bit_depth = 8;
+         return 1;
+
+      default:
+         return 0;
+   }
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static unsigned int
+sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
+    png_uint_32 x, unsigned int sample_index, int swap16, int littleendian)
+{
+   png_uint_32 bit_index, result;
+
+   /* Find a sample index for the desired sample: */
+   x *= bit_depth;
+   bit_index = x;
+
+   if ((colour_type & 1) == 0) /* !palette */
+   {
+      if (colour_type & 2)
+         bit_index *= 3;
+
+      if (colour_type & 4)
+         bit_index += x; /* Alpha channel */
+
+      /* Multiple channels; select one: */
+      if (colour_type & (2+4))
+         bit_index += sample_index * bit_depth;
+   }
+
+   /* Return the sample from the row as an integer. */
+   row += bit_index >> 3;
+   result = *row;
+
+   if (bit_depth == 8)
+      return result;
+
+   else if (bit_depth > 8)
+   {
+      if (swap16)
+         return (*++row << 8) + result;
+      else
+         return (result << 8) + *++row;
+   }
+
+   /* Less than 8 bits per sample.  By default PNG has the big end of
+    * the egg on the left of the screen, but if littleendian is set
+    * then the big end is on the right.
+    */
+   bit_index &= 7;
+
+   if (!littleendian)
+      bit_index = 8-bit_index-bit_depth;
+
+   return (result >> bit_index) & ((1U<<bit_depth)-1);
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+/* Copy a single pixel, of a given size, from one buffer to another -
+ * while this is basically bit addressed there is an implicit assumption
+ * that pixels 8 or more bits in size are byte aligned and that pixels
+ * do not otherwise cross byte boundaries.  (This is, so far as I know,
+ * universally true in bitmap computer graphics.  [JCB 20101212])
+ *
+ * NOTE: The to and from buffers may be the same.
+ */
+static void
+pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
+   png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize,
+   int littleendian)
+{
+   /* Assume we can multiply by 'size' without overflow because we are
+    * just working in a single buffer.
+    */
+   toIndex *= pixelSize;
+   fromIndex *= pixelSize;
+   if (pixelSize < 8) /* Sub-byte */
+   {
+      /* Mask to select the location of the copied pixel: */
+      unsigned int destMask = ((1U<<pixelSize)-1) <<
+         (littleendian ? toIndex&7 : 8-pixelSize-(toIndex&7));
+      /* The following read the entire pixels and clears the extra: */
+      unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
+      unsigned int sourceByte = fromBuffer[fromIndex >> 3];
+
+      /* Don't rely on << or >> supporting '0' here, just in case: */
+      fromIndex &= 7;
+      if (littleendian)
+      {
+         if (fromIndex > 0) sourceByte >>= fromIndex;
+         if ((toIndex & 7) > 0) sourceByte <<= toIndex & 7;
+      }
+
+      else
+      {
+         if (fromIndex > 0) sourceByte <<= fromIndex;
+         if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
+      }
+
+      toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
+   }
+   else /* One or more bytes */
+      memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* Copy a complete row of pixels, taking into account potential partial
+ * bytes at the end.
+ */
+static void
+row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth,
+      int littleendian)
+{
+   memcpy(toBuffer, fromBuffer, bitWidth >> 3);
+
+   if ((bitWidth & 7) != 0)
+   {
+      unsigned int mask;
+
+      toBuffer += bitWidth >> 3;
+      fromBuffer += bitWidth >> 3;
+      if (littleendian)
+         mask = 0xff << (bitWidth & 7);
+      else
+         mask = 0xff >> (bitWidth & 7);
+      *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
+   }
+}
+
+/* Compare pixels - they are assumed to start at the first byte in the
+ * given buffers.
+ */
+static int
+pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
+{
+#if PNG_LIBPNG_VER < 10506
+   if (memcmp(pa, pb, bit_width>>3) == 0)
+   {
+      png_uint_32 p;
+
+      if ((bit_width & 7) == 0) return 0;
+
+      /* Ok, any differences? */
+      p = pa[bit_width >> 3];
+      p ^= pb[bit_width >> 3];
+
+      if (p == 0) return 0;
+
+      /* There are, but they may not be significant, remove the bits
+       * after the end (the low order bits in PNG.)
+       */
+      bit_width &= 7;
+      p >>= 8-bit_width;
+
+      if (p == 0) return 0;
+   }
+#else
+   /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
+    * bits too:
+    */
+   if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
+      return 0;
+#endif
+
+   /* Return the index of the changed byte. */
+   {
+      png_uint_32 where = 0;
+
+      while (pa[where] == pb[where]) ++where;
+      return 1+where;
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/*************************** BASIC PNG FILE WRITING ***************************/
+/* A png_store takes data from the sequential writer or provides data
+ * to the sequential reader.  It can also store the result of a PNG
+ * write for later retrieval.
+ */
+#define STORE_BUFFER_SIZE 500 /* arbitrary */
+typedef struct png_store_buffer
+{
+   struct png_store_buffer*  prev;    /* NOTE: stored in reverse order */
+   png_byte                  buffer[STORE_BUFFER_SIZE];
+} png_store_buffer;
+
+#define FILE_NAME_SIZE 64
+
+typedef struct store_palette_entry /* record of a single palette entry */
+{
+   png_byte red;
+   png_byte green;
+   png_byte blue;
+   png_byte alpha;
+} store_palette_entry, store_palette[256];
+
+typedef struct png_store_file
+{
+   struct png_store_file*  next;      /* as many as you like... */
+   char                    name[FILE_NAME_SIZE];
+   unsigned int            IDAT_bits; /* Number of bits in IDAT size */
+   png_uint_32             IDAT_size; /* Total size of IDAT data */
+   png_uint_32             id;        /* must be correct (see FILEID) */
+   size_t                  datacount; /* In this (the last) buffer */
+   png_store_buffer        data;      /* Last buffer in file */
+   int                     npalette;  /* Number of entries in palette */
+   store_palette_entry*    palette;   /* May be NULL */
+} png_store_file;
+
+/* The following is a pool of memory allocated by a single libpng read or write
+ * operation.
+ */
+typedef struct store_pool
+{
+   struct png_store    *store;   /* Back pointer */
+   struct store_memory *list;    /* List of allocated memory */
+   png_byte             mark[4]; /* Before and after data */
+
+   /* Statistics for this run. */
+   png_alloc_size_t     max;     /* Maximum single allocation */
+   png_alloc_size_t     current; /* Current allocation */
+   png_alloc_size_t     limit;   /* Highest current allocation */
+   png_alloc_size_t     total;   /* Total allocation */
+
+   /* Overall statistics (retained across successive runs). */
+   png_alloc_size_t     max_max;
+   png_alloc_size_t     max_limit;
+   png_alloc_size_t     max_total;
+} store_pool;
+
+typedef struct png_store
+{
+   /* For cexcept.h exception handling - simply store one of these;
+    * the context is a self pointer but it may point to a different
+    * png_store (in fact it never does in this program.)
+    */
+   struct exception_context
+                      exception_context;
+
+   unsigned int       verbose :1;
+   unsigned int       treat_warnings_as_errors :1;
+   unsigned int       expect_error :1;
+   unsigned int       expect_warning :1;
+   unsigned int       saw_warning :1;
+   unsigned int       speed :1;
+   unsigned int       progressive :1; /* use progressive read */
+   unsigned int       validated :1;   /* used as a temporary flag */
+   int                nerrors;
+   int                nwarnings;
+   int                noptions;       /* number of options below: */
+   struct {
+      unsigned char   option;         /* option number, 0..30 */
+      unsigned char   setting;        /* setting (unset,invalid,on,off) */
+   }                  options[16];
+   char               test[128];      /* Name of test */
+   char               error[256];
+
+   /* Share fields */
+   png_uint_32        chunklen; /* Length of chunk+overhead (chunkpos >= 8) */
+   png_uint_32        chunktype;/* Type of chunk (valid if chunkpos >= 4) */
+   png_uint_32        chunkpos; /* Position in chunk */
+   png_uint_32        IDAT_size;/* Accumulated IDAT size in .new */
+   unsigned int       IDAT_bits;/* Cache of the file store value */
+
+   /* Read fields */
+   png_structp        pread;    /* Used to read a saved file */
+   png_infop          piread;
+   png_store_file*    current;  /* Set when reading */
+   png_store_buffer*  next;     /* Set when reading */
+   size_t             readpos;  /* Position in *next */
+   png_byte*          image;    /* Buffer for reading interlaced images */
+   size_t             cb_image; /* Size of this buffer */
+   size_t             cb_row;   /* Row size of the image(s) */
+   uLong              IDAT_crc;
+   png_uint_32        IDAT_len; /* Used when re-chunking IDAT chunks */
+   png_uint_32        IDAT_pos; /* Used when re-chunking IDAT chunks */
+   png_uint_32        image_h;  /* Number of rows in a single image */
+   store_pool         read_memory_pool;
+
+   /* Write fields */
+   png_store_file*    saved;
+   png_structp        pwrite;   /* Used when writing a new file */
+   png_infop          piwrite;
+   size_t             writepos; /* Position in .new */
+   char               wname[FILE_NAME_SIZE];
+   png_store_buffer   new;      /* The end of the new PNG file being written. */
+   store_pool         write_memory_pool;
+   store_palette_entry* palette;
+   int                  npalette;
+} png_store;
+
+/* Initialization and cleanup */
+static void
+store_pool_mark(png_bytep mark)
+{
+   static png_uint_32 store_seed[2] = { 0x12345678, 1};
+
+   make_four_random_bytes(store_seed, mark);
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Use this for random 32 bit values; this function makes sure the result is
+ * non-zero.
+ */
+static png_uint_32
+random_32(void)
+{
+
+   for (;;)
+   {
+      png_byte mark[4];
+      png_uint_32 result;
+
+      store_pool_mark(mark);
+      result = png_get_uint_32(mark);
+
+      if (result != 0)
+         return result;
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+static void
+store_pool_init(png_store *ps, store_pool *pool)
+{
+   memset(pool, 0, sizeof *pool);
+
+   pool->store = ps;
+   pool->list = NULL;
+   pool->max = pool->current = pool->limit = pool->total = 0;
+   pool->max_max = pool->max_limit = pool->max_total = 0;
+   store_pool_mark(pool->mark);
+}
+
+static void
+store_init(png_store* ps)
+{
+   memset(ps, 0, sizeof *ps);
+   init_exception_context(&ps->exception_context);
+   store_pool_init(ps, &ps->read_memory_pool);
+   store_pool_init(ps, &ps->write_memory_pool);
+   ps->verbose = 0;
+   ps->treat_warnings_as_errors = 0;
+   ps->expect_error = 0;
+   ps->expect_warning = 0;
+   ps->saw_warning = 0;
+   ps->speed = 0;
+   ps->progressive = 0;
+   ps->validated = 0;
+   ps->nerrors = ps->nwarnings = 0;
+   ps->pread = NULL;
+   ps->piread = NULL;
+   ps->saved = ps->current = NULL;
+   ps->next = NULL;
+   ps->readpos = 0;
+   ps->image = NULL;
+   ps->cb_image = 0;
+   ps->cb_row = 0;
+   ps->image_h = 0;
+   ps->pwrite = NULL;
+   ps->piwrite = NULL;
+   ps->writepos = 0;
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+   ps->IDAT_bits = 0;
+   ps->new.prev = NULL;
+   ps->palette = NULL;
+   ps->npalette = 0;
+   ps->noptions = 0;
+}
+
+static void
+store_freebuffer(png_store_buffer* psb)
+{
+   if (psb->prev)
+   {
+      store_freebuffer(psb->prev);
+      free(psb->prev);
+      psb->prev = NULL;
+   }
+}
+
+static void
+store_freenew(png_store *ps)
+{
+   store_freebuffer(&ps->new);
+   ps->writepos = 0;
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+   ps->IDAT_bits = 0;
+   if (ps->palette != NULL)
+   {
+      free(ps->palette);
+      ps->palette = NULL;
+      ps->npalette = 0;
+   }
+}
+
+static void
+store_storenew(png_store *ps)
+{
+   png_store_buffer *pb;
+
+   pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
+
+   if (pb == NULL)
+      png_error(ps->pwrite, "store new: OOM");
+
+   *pb = ps->new;
+   ps->new.prev = pb;
+   ps->writepos = 0;
+}
+
+static void
+store_freefile(png_store_file **ppf)
+{
+   if (*ppf != NULL)
+   {
+      store_freefile(&(*ppf)->next);
+
+      store_freebuffer(&(*ppf)->data);
+      (*ppf)->datacount = 0;
+      if ((*ppf)->palette != NULL)
+      {
+         free((*ppf)->palette);
+         (*ppf)->palette = NULL;
+         (*ppf)->npalette = 0;
+      }
+      free(*ppf);
+      *ppf = NULL;
+   }
+}
+
+static unsigned int
+bits_of(png_uint_32 num)
+{
+   /* Return the number of bits in 'num' */
+   unsigned int b = 0;
+
+   if (num & 0xffff0000U)  b += 16U, num >>= 16;
+   if (num & 0xff00U)      b += 8U, num >>= 8;
+   if (num & 0xf0U)        b += 4U, num >>= 4;
+   if (num & 0xcU)         b += 2U, num >>= 2;
+   if (num & 0x2U)         ++b, num >>= 1;
+   if (num)                ++b;
+
+   return b; /* 0..32 */
+}
+
+/* Main interface to file storage, after writing a new PNG file (see the API
+ * below) call store_storefile to store the result with the given name and id.
+ */
+static void
+store_storefile(png_store *ps, png_uint_32 id)
+{
+   png_store_file *pf;
+
+   if (ps->chunkpos != 0U || ps->chunktype != 0U || ps->chunklen != 0U ||
+       ps->IDAT_size == 0)
+      png_error(ps->pwrite, "storefile: incomplete write");
+
+   pf = voidcast(png_store_file*, malloc(sizeof *pf));
+   if (pf == NULL)
+      png_error(ps->pwrite, "storefile: OOM");
+   safecat(pf->name, sizeof pf->name, 0, ps->wname);
+   pf->id = id;
+   pf->data = ps->new;
+   pf->datacount = ps->writepos;
+   pf->IDAT_size = ps->IDAT_size;
+   pf->IDAT_bits = bits_of(ps->IDAT_size);
+   /* Because the IDAT always has zlib header stuff this must be true: */
+   if (pf->IDAT_bits == 0U)
+      png_error(ps->pwrite, "storefile: 0 sized IDAT");
+   ps->new.prev = NULL;
+   ps->writepos = 0;
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+   pf->palette = ps->palette;
+   pf->npalette = ps->npalette;
+   ps->palette = 0;
+   ps->npalette = 0;
+
+   /* And save it. */
+   pf->next = ps->saved;
+   ps->saved = pf;
+}
+
+/* Generate an error message (in the given buffer) */
+static size_t
+store_message(png_store *ps, png_const_structp pp, char *buffer, size_t bufsize,
+   size_t pos, const char *msg)
+{
+   if (pp != NULL && pp == ps->pread)
+   {
+      /* Reading a file */
+      pos = safecat(buffer, bufsize, pos, "read: ");
+
+      if (ps->current != NULL)
+      {
+         pos = safecat(buffer, bufsize, pos, ps->current->name);
+         pos = safecat(buffer, bufsize, pos, sep);
+      }
+   }
+
+   else if (pp != NULL && pp == ps->pwrite)
+   {
+      /* Writing a file */
+      pos = safecat(buffer, bufsize, pos, "write: ");
+      pos = safecat(buffer, bufsize, pos, ps->wname);
+      pos = safecat(buffer, bufsize, pos, sep);
+   }
+
+   else
+   {
+      /* Neither reading nor writing (or a memory error in struct delete) */
+      pos = safecat(buffer, bufsize, pos, "pngvalid: ");
+   }
+
+   if (ps->test[0] != 0)
+   {
+      pos = safecat(buffer, bufsize, pos, ps->test);
+      pos = safecat(buffer, bufsize, pos, sep);
+   }
+   pos = safecat(buffer, bufsize, pos, msg);
+   return pos;
+}
+
+/* Verbose output to the error stream: */
+static void
+store_verbose(png_store *ps, png_const_structp pp, png_const_charp prefix,
+   png_const_charp message)
+{
+   char buffer[512];
+
+   if (prefix)
+      fputs(prefix, stderr);
+
+   (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
+   fputs(buffer, stderr);
+   fputc('\n', stderr);
+}
+
+/* Log an error or warning - the relevant count is always incremented. */
+static void
+store_log(png_store* ps, png_const_structp pp, png_const_charp message,
+   int is_error)
+{
+   /* The warning is copied to the error buffer if there are no errors and it is
+    * the first warning.  The error is copied to the error buffer if it is the
+    * first error (overwriting any prior warnings).
+    */
+   if (is_error ? (ps->nerrors)++ == 0 :
+       (ps->nwarnings)++ == 0 && ps->nerrors == 0)
+      store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
+
+   if (ps->verbose)
+      store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* Internal error function, called with a png_store but no libpng stuff. */
+static void
+internal_error(png_store *ps, png_const_charp message)
+{
+   store_log(ps, NULL, message, 1 /* error */);
+
+   /* And finally throw an exception. */
+   {
+      struct exception_context *the_exception_context = &ps->exception_context;
+      Throw ps;
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* Functions to use as PNG callbacks. */
+static void PNGCBAPI
+store_error(png_structp ppIn, png_const_charp message) /* PNG_NORETURN */
+{
+   png_const_structp pp = ppIn;
+   png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
+
+   if (!ps->expect_error)
+      store_log(ps, pp, message, 1 /* error */);
+
+   /* And finally throw an exception. */
+   {
+      struct exception_context *the_exception_context = &ps->exception_context;
+      Throw ps;
+   }
+}
+
+static void PNGCBAPI
+store_warning(png_structp ppIn, png_const_charp message)
+{
+   png_const_structp pp = ppIn;
+   png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
+
+   if (!ps->expect_warning)
+      store_log(ps, pp, message, 0 /* warning */);
+   else
+      ps->saw_warning = 1;
+}
+
+/* These somewhat odd functions are used when reading an image to ensure that
+ * the buffer is big enough, the png_structp is for errors.
+ */
+/* Return a single row from the correct image. */
+static png_bytep
+store_image_row(const png_store* ps, png_const_structp pp, int nImage,
+   png_uint_32 y)
+{
+   size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
+
+   if (ps->image == NULL)
+      png_error(pp, "no allocated image");
+
+   if (coffset + ps->cb_row + 3 > ps->cb_image)
+      png_error(pp, "image too small");
+
+   return ps->image + coffset;
+}
+
+static void
+store_image_free(png_store *ps, png_const_structp pp)
+{
+   if (ps->image != NULL)
+   {
+      png_bytep image = ps->image;
+
+      if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
+      {
+         if (pp != NULL)
+            png_error(pp, "png_store image overwrite (1)");
+         else
+            store_log(ps, NULL, "png_store image overwrite (2)", 1);
+      }
+
+      ps->image = NULL;
+      ps->cb_image = 0;
+      --image;
+      free(image);
+   }
+}
+
+static void
+store_ensure_image(png_store *ps, png_const_structp pp, int nImages,
+   size_t cbRow, png_uint_32 cRows)
+{
+   size_t cb = nImages * cRows * (cbRow + 5);
+
+   if (ps->cb_image < cb)
+   {
+      png_bytep image;
+
+      store_image_free(ps, pp);
+
+      /* The buffer is deliberately mis-aligned. */
+      image = voidcast(png_bytep, malloc(cb+2));
+      if (image == NULL)
+      {
+         /* Called from the startup - ignore the error for the moment. */
+         if (pp == NULL)
+            return;
+
+         png_error(pp, "OOM allocating image buffer");
+      }
+
+      /* These magic tags are used to detect overwrites above. */
+      ++image;
+      image[-1] = 0xed;
+      image[cb] = 0xfe;
+
+      ps->image = image;
+      ps->cb_image = cb;
+   }
+
+   /* We have an adequate sized image; lay out the rows.  There are 2 bytes at
+    * the start and three at the end of each (this ensures that the row
+    * alignment starts out odd - 2+1 and changes for larger images on each row.)
+    */
+   ps->cb_row = cbRow;
+   ps->image_h = cRows;
+
+   /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
+    * This deliberately doesn't match the bits in the size test image which are
+    * outside the image; these are set to 0xff (all 1).  To make the row
+    * comparison work in the 'size' test case the size rows are pre-initialized
+    * to the same value prior to calling 'standard_row'.
+    */
+   memset(ps->image, 178, cb);
+
+   /* Then put in the marks. */
+   while (--nImages >= 0)
+   {
+      png_uint_32 y;
+
+      for (y=0; y<cRows; ++y)
+      {
+         png_bytep row = store_image_row(ps, pp, nImages, y);
+
+         /* The markers: */
+         row[-2] = 190;
+         row[-1] = 239;
+         row[cbRow] = 222;
+         row[cbRow+1] = 173;
+         row[cbRow+2] = 17;
+      }
+   }
+}
+
+#ifdef PNG_READ_SUPPORTED
+static void
+store_image_check(const png_store* ps, png_const_structp pp, int iImage)
+{
+   png_const_bytep image = ps->image;
+
+   if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
+      png_error(pp, "image overwrite");
+   else
+   {
+      size_t cbRow = ps->cb_row;
+      png_uint_32 rows = ps->image_h;
+
+      image += iImage * (cbRow+5) * ps->image_h;
+
+      image += 2; /* skip image first row markers */
+
+      for (; rows > 0; --rows)
+      {
+         if (image[-2] != 190 || image[-1] != 239)
+            png_error(pp, "row start overwritten");
+
+         if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
+            image[cbRow+2] != 17)
+            png_error(pp, "row end overwritten");
+
+         image += cbRow+5;
+      }
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+static int
+valid_chunktype(png_uint_32 chunktype)
+{
+   /* Each byte in the chunk type must be in one of the ranges 65..90, 97..122
+    * (both inclusive), so:
+    */
+   unsigned int i;
+
+   for (i=0; i<4; ++i)
+   {
+      unsigned int c = chunktype & 0xffU;
+
+      if (!((c >= 65U && c <= 90U) || (c >= 97U && c <= 122U)))
+         return 0;
+
+      chunktype >>= 8;
+   }
+
+   return 1; /* It's valid */
+}
+
+static void PNGCBAPI
+store_write(png_structp ppIn, png_bytep pb, size_t st)
+{
+   png_const_structp pp = ppIn;
+   png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
+   size_t writepos = ps->writepos;
+   png_uint_32 chunkpos = ps->chunkpos;
+   png_uint_32 chunktype = ps->chunktype;
+   png_uint_32 chunklen = ps->chunklen;
+
+   if (ps->pwrite != pp)
+      png_error(pp, "store state damaged");
+
+   /* Technically this is legal, but in practice libpng never writes more than
+    * the maximum chunk size at once so if it happens something weird has
+    * changed inside libpng (probably).
+    */
+   if (st > 0x7fffffffU)
+      png_error(pp, "unexpected write size");
+
+   /* Now process the bytes to be written.  Do this in units of the space in the
+    * output (write) buffer or, at the start 4 bytes for the chunk type and
+    * length limited in any case by the amount of data.
+    */
+   while (st > 0)
+   {
+      if (writepos >= STORE_BUFFER_SIZE)
+         store_storenew(ps), writepos = 0;
+
+      if (chunkpos < 4)
+      {
+         png_byte b = *pb++;
+         --st;
+         chunklen = (chunklen << 8) + b;
+         ps->new.buffer[writepos++] = b;
+         ++chunkpos;
+      }
+
+      else if (chunkpos < 8)
+      {
+         png_byte b = *pb++;
+         --st;
+         chunktype = (chunktype << 8) + b;
+         ps->new.buffer[writepos++] = b;
+
+         if (++chunkpos == 8)
+         {
+            chunklen &= 0xffffffffU;
+            if (chunklen > 0x7fffffffU)
+               png_error(pp, "chunk length too great");
+
+            chunktype &= 0xffffffffU;
+            if (chunktype == CHUNK_IDAT)
+            {
+               if (chunklen > ~ps->IDAT_size)
+                  png_error(pp, "pngvalid internal image too large");
+
+               ps->IDAT_size += chunklen;
+            }
+
+            else if (!valid_chunktype(chunktype))
+               png_error(pp, "invalid chunk type");
+
+            chunklen += 12; /* for header and CRC */
+         }
+      }
+
+      else /* chunkpos >= 8 */
+      {
+         size_t cb = st;
+
+         if (cb > STORE_BUFFER_SIZE - writepos)
+            cb = STORE_BUFFER_SIZE - writepos;
+
+         if (cb  > chunklen - chunkpos/* bytes left in chunk*/)
+            cb = (size_t)/*SAFE*/(chunklen - chunkpos);
+
+         memcpy(ps->new.buffer + writepos, pb, cb);
+         chunkpos += (png_uint_32)/*SAFE*/cb;
+         pb += cb;
+         writepos += cb;
+         st -= cb;
+
+         if (chunkpos >= chunklen) /* must be equal */
+            chunkpos = chunktype = chunklen = 0;
+      }
+   } /* while (st > 0) */
+
+   ps->writepos = writepos;
+   ps->chunkpos = chunkpos;
+   ps->chunktype = chunktype;
+   ps->chunklen = chunklen;
+}
+
+static void PNGCBAPI
+store_flush(png_structp ppIn)
+{
+   UNUSED(ppIn) /*DOES NOTHING*/
+}
+
+#ifdef PNG_READ_SUPPORTED
+static size_t
+store_read_buffer_size(png_store *ps)
+{
+   /* Return the bytes available for read in the current buffer. */
+   if (ps->next != &ps->current->data)
+      return STORE_BUFFER_SIZE;
+
+   return ps->current->datacount;
+}
+
+/* Return total bytes available for read. */
+static size_t
+store_read_buffer_avail(png_store *ps)
+{
+   if (ps->current != NULL && ps->next != NULL)
+   {
+      png_store_buffer *next = &ps->current->data;
+      size_t cbAvail = ps->current->datacount;
+
+      while (next != ps->next && next != NULL)
+      {
+         next = next->prev;
+         cbAvail += STORE_BUFFER_SIZE;
+      }
+
+      if (next != ps->next)
+         png_error(ps->pread, "buffer read error");
+
+      if (cbAvail > ps->readpos)
+         return cbAvail - ps->readpos;
+   }
+
+   return 0;
+}
+
+static int
+store_read_buffer_next(png_store *ps)
+{
+   png_store_buffer *pbOld = ps->next;
+   png_store_buffer *pbNew = &ps->current->data;
+   if (pbOld != pbNew)
+   {
+      while (pbNew != NULL && pbNew->prev != pbOld)
+         pbNew = pbNew->prev;
+
+      if (pbNew != NULL)
+      {
+         ps->next = pbNew;
+         ps->readpos = 0;
+         return 1;
+      }
+
+      png_error(ps->pread, "buffer lost");
+   }
+
+   return 0; /* EOF or error */
+}
+
+/* Need separate implementation and callback to allow use of the same code
+ * during progressive read, where the io_ptr is set internally by libpng.
+ */
+static void
+store_read_imp(png_store *ps, png_bytep pb, size_t st)
+{
+   if (ps->current == NULL || ps->next == NULL)
+      png_error(ps->pread, "store state damaged");
+
+   while (st > 0)
+   {
+      size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
+
+      if (cbAvail > 0)
+      {
+         if (cbAvail > st) cbAvail = st;
+         memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
+         st -= cbAvail;
+         pb += cbAvail;
+         ps->readpos += cbAvail;
+      }
+
+      else if (!store_read_buffer_next(ps))
+         png_error(ps->pread, "read beyond end of file");
+   }
+}
+
+static size_t
+store_read_chunk(png_store *ps, png_bytep pb, size_t max, size_t min)
+{
+   png_uint_32 chunklen = ps->chunklen;
+   png_uint_32 chunktype = ps->chunktype;
+   png_uint_32 chunkpos = ps->chunkpos;
+   size_t st = max;
+
+   if (st > 0) do
+   {
+      if (chunkpos >= chunklen) /* end of last chunk */
+      {
+         png_byte buffer[8];
+
+         /* Read the header of the next chunk: */
+         store_read_imp(ps, buffer, 8U);
+         chunklen = png_get_uint_32(buffer) + 12U;
+         chunktype = png_get_uint_32(buffer+4U);
+         chunkpos = 0U; /* Position read so far */
+      }
+
+      if (chunktype == CHUNK_IDAT)
+      {
+         png_uint_32 IDAT_pos = ps->IDAT_pos;
+         png_uint_32 IDAT_len = ps->IDAT_len;
+         png_uint_32 IDAT_size = ps->IDAT_size;
+
+         /* The IDAT headers are constructed here; skip the input header. */
+         if (chunkpos < 8U)
+            chunkpos = 8U;
+
+         if (IDAT_pos == IDAT_len)
+         {
+            png_byte random = random_byte();
+
+            /* Make a new IDAT chunk, if IDAT_len is 0 this is the first IDAT,
+             * if IDAT_size is 0 this is the end.  At present this is set up
+             * using a random number so that there is a 25% chance before
+             * the start of the first IDAT chunk being 0 length.
+             */
+            if (IDAT_len == 0U) /* First IDAT */
+            {
+               switch (random & 3U)
+               {
+                  case 0U: IDAT_len = 12U; break; /* 0 bytes */
+                  case 1U: IDAT_len = 13U; break; /* 1 byte */
+                  default: IDAT_len = random_u32();
+                           IDAT_len %= IDAT_size;
+                           IDAT_len += 13U; /* 1..IDAT_size bytes */
+                           break;
+               }
+            }
+
+            else if (IDAT_size == 0U) /* all IDAT data read */
+            {
+               /* The last (IDAT) chunk should be positioned at the CRC now: */
+               if (chunkpos != chunklen-4U)
+                  png_error(ps->pread, "internal: IDAT size mismatch");
+
+               /* The only option here is to add a zero length IDAT, this
+                * happens 25% of the time.  Because of the check above
+                * chunklen-4U-chunkpos must be zero, we just need to skip the
+                * CRC now.
+                */
+               if ((random & 3U) == 0U)
+                  IDAT_len = 12U; /* Output another 0 length IDAT */
+
+               else
+               {
+                  /* End of IDATs, skip the CRC to make the code above load the
+                   * next chunk header next time round.
+                   */
+                  png_byte buffer[4];
+
+                  store_read_imp(ps, buffer, 4U);
+                  chunkpos += 4U;
+                  ps->IDAT_pos = IDAT_pos;
+                  ps->IDAT_len = IDAT_len;
+                  ps->IDAT_size = 0U;
+                  continue; /* Read the next chunk */
+               }
+            }
+
+            else
+            {
+               /* Middle of IDATs, use 'random' to determine the number of bits
+                * to use in the IDAT length.
+                */
+               IDAT_len = random_u32();
+               IDAT_len &= (1U << (1U + random % ps->IDAT_bits)) - 1U;
+               if (IDAT_len > IDAT_size)
+                  IDAT_len = IDAT_size;
+               IDAT_len += 12U; /* zero bytes may occur */
+            }
+
+            IDAT_pos = 0U;
+            ps->IDAT_crc = 0x35af061e; /* Ie: crc32(0UL, "IDAT", 4) */
+         } /* IDAT_pos == IDAT_len */
+
+         if (IDAT_pos < 8U) /* Return the header */ do
+         {
+            png_uint_32 b;
+            unsigned int shift;
+
+            if (IDAT_pos < 4U)
+               b = IDAT_len - 12U;
+
+            else
+               b = CHUNK_IDAT;
+
+            shift = 3U & IDAT_pos;
+            ++IDAT_pos;
+
+            if (shift < 3U)
+               b >>= 8U*(3U-shift);
+
+            *pb++ = 0xffU & b;
+         }
+         while (--st > 0 && IDAT_pos < 8);
+
+         else if (IDAT_pos < IDAT_len - 4U) /* I.e not the CRC */
+         {
+            if (chunkpos < chunklen-4U)
+            {
+               uInt avail = (uInt)-1;
+
+               if (avail > (IDAT_len-4U) - IDAT_pos)
+                  avail = (uInt)/*SAFE*/((IDAT_len-4U) - IDAT_pos);
+
+               if (avail > st)
+                  avail = (uInt)/*SAFE*/st;
+
+               if (avail > (chunklen-4U) - chunkpos)
+                  avail = (uInt)/*SAFE*/((chunklen-4U) - chunkpos);
+
+               store_read_imp(ps, pb, avail);
+               ps->IDAT_crc = crc32(ps->IDAT_crc, pb, avail);
+               pb += (size_t)/*SAFE*/avail;
+               st -= (size_t)/*SAFE*/avail;
+               chunkpos += (png_uint_32)/*SAFE*/avail;
+               IDAT_size -= (png_uint_32)/*SAFE*/avail;
+               IDAT_pos += (png_uint_32)/*SAFE*/avail;
+            }
+
+            else /* skip the input CRC */
+            {
+               png_byte buffer[4];
+
+               store_read_imp(ps, buffer, 4U);
+               chunkpos += 4U;
+            }
+         }
+
+         else /* IDAT crc */ do
+         {
+            uLong b = ps->IDAT_crc;
+            unsigned int shift = (IDAT_len - IDAT_pos); /* 4..1 */
+            ++IDAT_pos;
+
+            if (shift > 1U)
+               b >>= 8U*(shift-1U);
+
+            *pb++ = 0xffU & b;
+         }
+         while (--st > 0 && IDAT_pos < IDAT_len);
+
+         ps->IDAT_pos = IDAT_pos;
+         ps->IDAT_len = IDAT_len;
+         ps->IDAT_size = IDAT_size;
+      }
+
+      else /* !IDAT */
+      {
+         /* If there is still some pending IDAT data after the IDAT chunks have
+          * been processed there is a problem:
+          */
+         if (ps->IDAT_len > 0 && ps->IDAT_size > 0)
+            png_error(ps->pread, "internal: missing IDAT data");
+
+         if (chunktype == CHUNK_IEND && ps->IDAT_len == 0U)
+            png_error(ps->pread, "internal: missing IDAT");
+
+         if (chunkpos < 8U) /* Return the header */ do
+         {
+            png_uint_32 b;
+            unsigned int shift;
+
+            if (chunkpos < 4U)
+               b = chunklen - 12U;
+
+            else
+               b = chunktype;
+
+            shift = 3U & chunkpos;
+            ++chunkpos;
+
+            if (shift < 3U)
+               b >>= 8U*(3U-shift);
+
+            *pb++ = 0xffU & b;
+         }
+         while (--st > 0 && chunkpos < 8);
+
+         else /* Return chunk bytes, including the CRC */
+         {
+            size_t avail = st;
+
+            if (avail > chunklen - chunkpos)
+               avail = (size_t)/*SAFE*/(chunklen - chunkpos);
+
+            store_read_imp(ps, pb, avail);
+            pb += avail;
+            st -= avail;
+            chunkpos += (png_uint_32)/*SAFE*/avail;
+
+            /* Check for end of chunk and end-of-file; don't try to read a new
+             * chunk header at this point unless instructed to do so by 'min'.
+             */
+            if (chunkpos >= chunklen && max-st >= min &&
+                     store_read_buffer_avail(ps) == 0)
+               break;
+         }
+      } /* !IDAT */
+   }
+   while (st > 0);
+
+   ps->chunklen = chunklen;
+   ps->chunktype = chunktype;
+   ps->chunkpos = chunkpos;
+
+   return st; /* space left */
+}
+
+static void PNGCBAPI
+store_read(png_structp ppIn, png_bytep pb, size_t st)
+{
+   png_const_structp pp = ppIn;
+   png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
+
+   if (ps == NULL || ps->pread != pp)
+      png_error(pp, "bad store read call");
+
+   store_read_chunk(ps, pb, st, st);
+}
+
+static void
+store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
+{
+   if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
+      png_error(pp, "store state damaged (progressive)");
+
+   /* This is another Horowitz and Hill random noise generator.  In this case
+    * the aim is to stress the progressive reader with truly horrible variable
+    * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
+    * is generated.  We could probably just count from 1 to 32767 and get as
+    * good a result.
+    */
+   while (store_read_buffer_avail(ps) > 0)
+   {
+      static png_uint_32 noise = 2;
+      size_t cb;
+      png_byte buffer[512];
+
+      /* Generate 15 more bits of stuff: */
+      noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
+      cb = noise & 0x1ff;
+      cb -= store_read_chunk(ps, buffer, cb, 1);
+      png_process_data(pp, pi, buffer, cb);
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* The caller must fill this in: */
+static store_palette_entry *
+store_write_palette(png_store *ps, int npalette)
+{
+   if (ps->pwrite == NULL)
+      store_log(ps, NULL, "attempt to write palette without write stream", 1);
+
+   if (ps->palette != NULL)
+      png_error(ps->pwrite, "multiple store_write_palette calls");
+
+   /* This function can only return NULL if called with '0'! */
+   if (npalette > 0)
+   {
+      ps->palette = voidcast(store_palette_entry*, malloc(npalette *
+         sizeof *ps->palette));
+
+      if (ps->palette == NULL)
+         png_error(ps->pwrite, "store new palette: OOM");
+
+      ps->npalette = npalette;
+   }
+
+   return ps->palette;
+}
+
+#ifdef PNG_READ_SUPPORTED
+static store_palette_entry *
+store_current_palette(png_store *ps, int *npalette)
+{
+   /* This is an internal error (the call has been made outside a read
+    * operation.)
+    */
+   if (ps->current == NULL)
+   {
+      store_log(ps, ps->pread, "no current stream for palette", 1);
+      return NULL;
+   }
+
+   /* The result may be null if there is no palette. */
+   *npalette = ps->current->npalette;
+   return ps->current->palette;
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/***************************** MEMORY MANAGEMENT*** ***************************/
+#ifdef PNG_USER_MEM_SUPPORTED
+/* A store_memory is simply the header for an allocated block of memory.  The
+ * pointer returned to libpng is just after the end of the header block, the
+ * allocated memory is followed by a second copy of the 'mark'.
+ */
+typedef struct store_memory
+{
+   store_pool          *pool;    /* Originating pool */
+   struct store_memory *next;    /* Singly linked list */
+   png_alloc_size_t     size;    /* Size of memory allocated */
+   png_byte             mark[4]; /* ID marker */
+} store_memory;
+
+/* Handle a fatal error in memory allocation.  This calls png_error if the
+ * libpng struct is non-NULL, else it outputs a message and returns.  This means
+ * that a memory problem while libpng is running will abort (png_error) the
+ * handling of particular file while one in cleanup (after the destroy of the
+ * struct has returned) will simply keep going and free (or attempt to free)
+ * all the memory.
+ */
+static void
+store_pool_error(png_store *ps, png_const_structp pp, const char *msg)
+{
+   if (pp != NULL)
+      png_error(pp, msg);
+
+   /* Else we have to do it ourselves.  png_error eventually calls store_log,
+    * above.  store_log accepts a NULL png_structp - it just changes what gets
+    * output by store_message.
+    */
+   store_log(ps, pp, msg, 1 /* error */);
+}
+
+static void
+store_memory_free(png_const_structp pp, store_pool *pool, store_memory *memory)
+{
+   /* Note that pp may be NULL (see store_pool_delete below), the caller has
+    * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
+    * pointer (for sure), but the contents may have been trashed.
+    */
+   if (memory->pool != pool)
+      store_pool_error(pool->store, pp, "memory corrupted (pool)");
+
+   else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
+      store_pool_error(pool->store, pp, "memory corrupted (start)");
+
+   /* It should be safe to read the size field now. */
+   else
+   {
+      png_alloc_size_t cb = memory->size;
+
+      if (cb > pool->max)
+         store_pool_error(pool->store, pp, "memory corrupted (size)");
+
+      else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
+         != 0)
+         store_pool_error(pool->store, pp, "memory corrupted (end)");
+
+      /* Finally give the library a chance to find problems too: */
+      else
+         {
+         pool->current -= cb;
+         free(memory);
+         }
+   }
+}
+
+static void
+store_pool_delete(png_store *ps, store_pool *pool)
+{
+   if (pool->list != NULL)
+   {
+      fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
+         pool == &ps->read_memory_pool ? "read" : "write",
+         pool == &ps->read_memory_pool ? (ps->current != NULL ?
+            ps->current->name : "unknown file") : ps->wname);
+      ++ps->nerrors;
+
+      do
+      {
+         store_memory *next = pool->list;
+         pool->list = next->next;
+         next->next = NULL;
+
+         fprintf(stderr, "\t%lu bytes @ %p\n",
+             (unsigned long)next->size, (const void*)(next+1));
+         /* The NULL means this will always return, even if the memory is
+          * corrupted.
+          */
+         store_memory_free(NULL, pool, next);
+      }
+      while (pool->list != NULL);
+   }
+
+   /* And reset the other fields too for the next time. */
+   if (pool->max > pool->max_max) pool->max_max = pool->max;
+   pool->max = 0;
+   if (pool->current != 0) /* unexpected internal error */
+      fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
+         ps->test, pool == &ps->read_memory_pool ? "read" : "write",
+         pool == &ps->read_memory_pool ? (ps->current != NULL ?
+            ps->current->name : "unknown file") : ps->wname);
+   pool->current = 0;
+
+   if (pool->limit > pool->max_limit)
+      pool->max_limit = pool->limit;
+
+   pool->limit = 0;
+
+   if (pool->total > pool->max_total)
+      pool->max_total = pool->total;
+
+   pool->total = 0;
+
+   /* Get a new mark too. */
+   store_pool_mark(pool->mark);
+}
+
+/* The memory callbacks: */
+static png_voidp PNGCBAPI
+store_malloc(png_structp ppIn, png_alloc_size_t cb)
+{
+   png_const_structp pp = ppIn;
+   store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
+   store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
+      (sizeof pool->mark)));
+
+   if (new != NULL)
+   {
+      if (cb > pool->max)
+         pool->max = cb;
+
+      pool->current += cb;
+
+      if (pool->current > pool->limit)
+         pool->limit = pool->current;
+
+      pool->total += cb;
+
+      new->size = cb;
+      memcpy(new->mark, pool->mark, sizeof new->mark);
+      memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
+      new->pool = pool;
+      new->next = pool->list;
+      pool->list = new;
+      ++new;
+   }
+
+   else
+   {
+      /* NOTE: the PNG user malloc function cannot use the png_ptr it is passed
+       * other than to retrieve the allocation pointer!  libpng calls the
+       * store_malloc callback in two basic cases:
+       *
+       * 1) From png_malloc; png_malloc will do a png_error itself if NULL is
+       *    returned.
+       * 2) From png_struct or png_info structure creation; png_malloc is
+       *    to return so cleanup can be performed.
+       *
+       * To handle this store_malloc can log a message, but can't do anything
+       * else.
+       */
+      store_log(pool->store, pp, "out of memory", 1 /* is_error */);
+   }
+
+   return new;
+}
+
+static void PNGCBAPI
+store_free(png_structp ppIn, png_voidp memory)
+{
+   png_const_structp pp = ppIn;
+   store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
+   store_memory *this = voidcast(store_memory*, memory), **test;
+
+   /* Because libpng calls store_free with a dummy png_struct when deleting
+    * png_struct or png_info via png_destroy_struct_2 it is necessary to check
+    * the passed in png_structp to ensure it is valid, and not pass it to
+    * png_error if it is not.
+    */
+   if (pp != pool->store->pread && pp != pool->store->pwrite)
+      pp = NULL;
+
+   /* First check that this 'memory' really is valid memory - it must be in the
+    * pool list.  If it is, use the shared memory_free function to free it.
+    */
+   --this;
+   for (test = &pool->list; *test != this; test = &(*test)->next)
+   {
+      if (*test == NULL)
+      {
+         store_pool_error(pool->store, pp, "bad pointer to free");
+         return;
+      }
+   }
+
+   /* Unlink this entry, *test == this. */
+   *test = this->next;
+   this->next = NULL;
+   store_memory_free(pp, pool, this);
+}
+#endif /* PNG_USER_MEM_SUPPORTED */
+
+/* Setup functions. */
+/* Cleanup when aborting a write or after storing the new file. */
+static void
+store_write_reset(png_store *ps)
+{
+   if (ps->pwrite != NULL)
+   {
+      anon_context(ps);
+
+      Try
+         png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
+
+      Catch_anonymous
+      {
+         /* memory corruption: continue. */
+      }
+
+      ps->pwrite = NULL;
+      ps->piwrite = NULL;
+   }
+
+   /* And make sure that all the memory has been freed - this will output
+    * spurious errors in the case of memory corruption above, but this is safe.
+    */
+#  ifdef PNG_USER_MEM_SUPPORTED
+      store_pool_delete(ps, &ps->write_memory_pool);
+#  endif
+
+   store_freenew(ps);
+}
+
+/* The following is the main write function, it returns a png_struct and,
+ * optionally, a png_info suitable for writiing a new PNG file.  Use
+ * store_storefile above to record this file after it has been written.  The
+ * returned libpng structures as destroyed by store_write_reset above.
+ */
+static png_structp
+set_store_for_write(png_store *ps, png_infopp ppi, const char *name)
+{
+   anon_context(ps);
+
+   Try
+   {
+      if (ps->pwrite != NULL)
+         png_error(ps->pwrite, "write store already in use");
+
+      store_write_reset(ps);
+      safecat(ps->wname, sizeof ps->wname, 0, name);
+
+      /* Don't do the slow memory checks if doing a speed test, also if user
+       * memory is not supported we can't do it anyway.
+       */
+#     ifdef PNG_USER_MEM_SUPPORTED
+         if (!ps->speed)
+            ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
+               ps, store_error, store_warning, &ps->write_memory_pool,
+               store_malloc, store_free);
+
+         else
+#     endif
+         ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+            ps, store_error, store_warning);
+
+      png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
+
+#     ifdef PNG_SET_OPTION_SUPPORTED
+         {
+            int opt;
+            for (opt=0; opt<ps->noptions; ++opt)
+               if (png_set_option(ps->pwrite, ps->options[opt].option,
+                  ps->options[opt].setting) == PNG_OPTION_INVALID)
+                  png_error(ps->pwrite, "png option invalid");
+         }
+#     endif
+
+      if (ppi != NULL)
+         *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
+   }
+
+   Catch_anonymous
+      return NULL;
+
+   return ps->pwrite;
+}
+
+/* Cleanup when finished reading (either due to error or in the success case).
+ * This routine exists even when there is no read support to make the code
+ * tidier (avoid a mass of ifdefs) and so easier to maintain.
+ */
+static void
+store_read_reset(png_store *ps)
+{
+#  ifdef PNG_READ_SUPPORTED
+      if (ps->pread != NULL)
+      {
+         anon_context(ps);
+
+         Try
+            png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
+
+         Catch_anonymous
+         {
+            /* error already output: continue */
+         }
+
+         ps->pread = NULL;
+         ps->piread = NULL;
+      }
+#  endif
+
+#  ifdef PNG_USER_MEM_SUPPORTED
+      /* Always do this to be safe. */
+      store_pool_delete(ps, &ps->read_memory_pool);
+#  endif
+
+   ps->current = NULL;
+   ps->next = NULL;
+   ps->readpos = 0;
+   ps->validated = 0;
+
+   ps->chunkpos = 8;
+   ps->chunktype = 0;
+   ps->chunklen = 16;
+   ps->IDAT_size = 0;
+}
+
+#ifdef PNG_READ_SUPPORTED
+static void
+store_read_set(png_store *ps, png_uint_32 id)
+{
+   png_store_file *pf = ps->saved;
+
+   while (pf != NULL)
+   {
+      if (pf->id == id)
+      {
+         ps->current = pf;
+         ps->next = NULL;
+         ps->IDAT_size = pf->IDAT_size;
+         ps->IDAT_bits = pf->IDAT_bits; /* just a cache */
+         ps->IDAT_len = 0;
+         ps->IDAT_pos = 0;
+         ps->IDAT_crc = 0UL;
+         store_read_buffer_next(ps);
+         return;
+      }
+
+      pf = pf->next;
+   }
+
+   {
+      size_t pos;
+      char msg[FILE_NAME_SIZE+64];
+
+      pos = standard_name_from_id(msg, sizeof msg, 0, id);
+      pos = safecat(msg, sizeof msg, pos, ": file not found");
+      png_error(ps->pread, msg);
+   }
+}
+
+/* The main interface for reading a saved file - pass the id number of the file
+ * to retrieve.  Ids must be unique or the earlier file will be hidden.  The API
+ * returns a png_struct and, optionally, a png_info.  Both of these will be
+ * destroyed by store_read_reset above.
+ */
+static png_structp
+set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
+   const char *name)
+{
+   /* Set the name for png_error */
+   safecat(ps->test, sizeof ps->test, 0, name);
+
+   if (ps->pread != NULL)
+      png_error(ps->pread, "read store already in use");
+
+   store_read_reset(ps);
+
+   /* Both the create APIs can return NULL if used in their default mode
+    * (because there is no other way of handling an error because the jmp_buf
+    * by default is stored in png_struct and that has not been allocated!)
+    * However, given that store_error works correctly in these circumstances
+    * we don't ever expect NULL in this program.
+    */
+#  ifdef PNG_USER_MEM_SUPPORTED
+      if (!ps->speed)
+         ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
+             store_error, store_warning, &ps->read_memory_pool, store_malloc,
+             store_free);
+
+      else
+#  endif
+   ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps, store_error,
+      store_warning);
+
+   if (ps->pread == NULL)
+   {
+      struct exception_context *the_exception_context = &ps->exception_context;
+
+      store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
+         1 /*error*/);
+
+      Throw ps;
+   }
+
+#  ifdef PNG_SET_OPTION_SUPPORTED
+      {
+         int opt;
+         for (opt=0; opt<ps->noptions; ++opt)
+            if (png_set_option(ps->pread, ps->options[opt].option,
+               ps->options[opt].setting) == PNG_OPTION_INVALID)
+                  png_error(ps->pread, "png option invalid");
+      }
+#  endif
+
+   store_read_set(ps, id);
+
+   if (ppi != NULL)
+      *ppi = ps->piread = png_create_info_struct(ps->pread);
+
+   return ps->pread;
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* The overall cleanup of a store simply calls the above then removes all the
+ * saved files.  This does not delete the store itself.
+ */
+static void
+store_delete(png_store *ps)
+{
+   store_write_reset(ps);
+   store_read_reset(ps);
+   store_freefile(&ps->saved);
+   store_image_free(ps, NULL);
+}
+
+/*********************** PNG FILE MODIFICATION ON READ ************************/
+/* Files may be modified on read.  The following structure contains a complete
+ * png_store together with extra members to handle modification and a special
+ * read callback for libpng.  To use this the 'modifications' field must be set
+ * to a list of png_modification structures that actually perform the
+ * modification, otherwise a png_modifier is functionally equivalent to a
+ * png_store.  There is a special read function, set_modifier_for_read, which
+ * replaces set_store_for_read.
+ */
+typedef enum modifier_state
+{
+   modifier_start,                        /* Initial value */
+   modifier_signature,                    /* Have a signature */
+   modifier_IHDR                          /* Have an IHDR */
+} modifier_state;
+
+typedef struct CIE_color
+{
+   /* A single CIE tristimulus value, representing the unique response of a
+    * standard observer to a variety of light spectra.  The observer recognizes
+    * all spectra that produce this response as the same color, therefore this
+    * is effectively a description of a color.
+    */
+   double X, Y, Z;
+} CIE_color;
+
+typedef struct color_encoding
+{
+   /* A description of an (R,G,B) encoding of color (as defined above); this
+    * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
+    * (0,0,1) plus an encoding value that is used to encode the linear
+    * components R, G and B to give the actual values R^gamma, G^gamma and
+    * B^gamma that are stored.
+    */
+   double    gamma;            /* Encoding (file) gamma of space */
+   CIE_color red, green, blue; /* End points */
+} color_encoding;
+
+#ifdef PNG_READ_SUPPORTED
+#if defined PNG_READ_TRANSFORMS_SUPPORTED && defined PNG_READ_cHRM_SUPPORTED
+static double
+chromaticity_x(CIE_color c)
+{
+   return c.X / (c.X + c.Y + c.Z);
+}
+
+static double
+chromaticity_y(CIE_color c)
+{
+   return c.Y / (c.X + c.Y + c.Z);
+}
+
+static CIE_color
+white_point(const color_encoding *encoding)
+{
+   CIE_color white;
+
+   white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
+   white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
+   white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
+
+   return white;
+}
+#endif /* READ_TRANSFORMS && READ_cHRM */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+static void
+normalize_color_encoding(color_encoding *encoding)
+{
+   const double whiteY = encoding->red.Y + encoding->green.Y +
+      encoding->blue.Y;
+
+   if (whiteY != 1)
+   {
+      encoding->red.X /= whiteY;
+      encoding->red.Y /= whiteY;
+      encoding->red.Z /= whiteY;
+      encoding->green.X /= whiteY;
+      encoding->green.Y /= whiteY;
+      encoding->green.Z /= whiteY;
+      encoding->blue.X /= whiteY;
+      encoding->blue.Y /= whiteY;
+      encoding->blue.Z /= whiteY;
+   }
+}
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static size_t
+safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
+   const color_encoding *e, double encoding_gamma)
+{
+   if (e != 0)
+   {
+      if (encoding_gamma != 0)
+         pos = safecat(buffer, bufsize, pos, "(");
+      pos = safecat(buffer, bufsize, pos, "R(");
+      pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
+      pos = safecat(buffer, bufsize, pos, "),G(");
+      pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
+      pos = safecat(buffer, bufsize, pos, "),B(");
+      pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
+      pos = safecat(buffer, bufsize, pos, ")");
+      if (encoding_gamma != 0)
+         pos = safecat(buffer, bufsize, pos, ")");
+   }
+
+   if (encoding_gamma != 0)
+   {
+      pos = safecat(buffer, bufsize, pos, "^");
+      pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
+   }
+
+   return pos;
+}
+#endif /* READ_TRANSFORMS */
+#endif /* PNG_READ_SUPPORTED */
+
+typedef struct png_modifier
+{
+   png_store               this;             /* I am a png_store */
+   struct png_modification *modifications;   /* Changes to make */
+
+   modifier_state           state;           /* My state */
+
+   /* Information from IHDR: */
+   png_byte                 bit_depth;       /* From IHDR */
+   png_byte                 colour_type;     /* From IHDR */
+
+   /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
+    * other chunks to be inserted.
+    */
+   png_uint_32              pending_len;
+   png_uint_32              pending_chunk;
+
+   /* Test values */
+   double                   *gammas;
+   unsigned int              ngammas;
+   unsigned int              ngamma_tests;     /* Number of gamma tests to run*/
+   double                    current_gamma;    /* 0 if not set */
+   const color_encoding *encodings;
+   unsigned int              nencodings;
+   const color_encoding *current_encoding; /* If an encoding has been set */
+   unsigned int              encoding_counter; /* For iteration */
+   int                       encoding_ignored; /* Something overwrote it */
+
+   /* Control variables used to iterate through possible encodings, the
+    * following must be set to 0 and tested by the function that uses the
+    * png_modifier because the modifier only sets it to 1 (true.)
+    */
+   unsigned int              repeat :1;   /* Repeat this transform test. */
+   unsigned int              test_uses_encoding :1;
+
+   /* Lowest sbit to test (pre-1.7 libpng fails for sbit < 8) */
+   png_byte                 sbitlow;
+
+   /* Error control - these are the limits on errors accepted by the gamma tests
+    * below.
+    */
+   double                   maxout8;  /* Maximum output value error */
+   double                   maxabs8;  /* Absolute sample error 0..1 */
+   double                   maxcalc8; /* Absolute sample error 0..1 */
+   double                   maxpc8;   /* Percentage sample error 0..100% */
+   double                   maxout16; /* Maximum output value error */
+   double                   maxabs16; /* Absolute sample error 0..1 */
+   double                   maxcalc16;/* Absolute sample error 0..1 */
+   double                   maxcalcG; /* Absolute sample error 0..1 */
+   double                   maxpc16;  /* Percentage sample error 0..100% */
+
+   /* This is set by transforms that need to allow a higher limit, it is an
+    * internal check on pngvalid to ensure that the calculated error limits are
+    * not ridiculous; without this it is too easy to make a mistake in pngvalid
+    * that allows any value through.
+    *
+    * NOTE: this is not checked in release builds.
+    */
+   double                   limit;    /* limit on error values, normally 4E-3 */
+
+   /* Log limits - values above this are logged, but not necessarily
+    * warned.
+    */
+   double                   log8;     /* Absolute error in 8 bits to log */
+   double                   log16;    /* Absolute error in 16 bits to log */
+
+   /* Logged 8 and 16 bit errors ('output' values): */
+   double                   error_gray_2;
+   double                   error_gray_4;
+   double                   error_gray_8;
+   double                   error_gray_16;
+   double                   error_color_8;
+   double                   error_color_16;
+   double                   error_indexed;
+
+   /* Flags: */
+   /* Whether to call png_read_update_info, not png_read_start_image, and how
+    * many times to call it.
+    */
+   int                      use_update_info;
+
+   /* Whether or not to interlace. */
+   int                      interlace_type :9; /* int, but must store '1' */
+
+   /* Run the standard tests? */
+   unsigned int             test_standard :1;
+
+   /* Run the odd-sized image and interlace read/write tests? */
+   unsigned int             test_size :1;
+
+   /* Run tests on reading with a combination of transforms, */
+   unsigned int             test_transform :1;
+   unsigned int             test_tRNS :1; /* Includes tRNS images */
+
+   /* When to use the use_input_precision option, this controls the gamma
+    * validation code checks.  If set any value that is within the transformed
+    * range input-.5 to input+.5 will be accepted, otherwise the value must be
+    * within the normal limits.  It should not be necessary to set this; the
+    * result should always be exact within the permitted error limits.
+    */
+   unsigned int             use_input_precision :1;
+   unsigned int             use_input_precision_sbit :1;
+   unsigned int             use_input_precision_16to8 :1;
+
+   /* If set assume that the calculation bit depth is set by the input
+    * precision, not the output precision.
+    */
+   unsigned int             calculations_use_input_precision :1;
+
+   /* If set assume that the calculations are done in 16 bits even if the sample
+    * depth is 8 bits.
+    */
+   unsigned int             assume_16_bit_calculations :1;
+
+   /* Which gamma tests to run: */
+   unsigned int             test_gamma_threshold :1;
+   unsigned int             test_gamma_transform :1; /* main tests */
+   unsigned int             test_gamma_sbit :1;
+   unsigned int             test_gamma_scale16 :1;
+   unsigned int             test_gamma_background :1;
+   unsigned int             test_gamma_alpha_mode :1;
+   unsigned int             test_gamma_expand16 :1;
+   unsigned int             test_exhaustive :1;
+
+   /* Whether or not to run the low-bit-depth grayscale tests.  This fails on
+    * gamma images in some cases because of gross inaccuracies in the grayscale
+    * gamma handling for low bit depth.
+    */
+   unsigned int             test_lbg :1;
+   unsigned int             test_lbg_gamma_threshold :1;
+   unsigned int             test_lbg_gamma_transform :1;
+   unsigned int             test_lbg_gamma_sbit :1;
+   unsigned int             test_lbg_gamma_composition :1;
+
+   unsigned int             log :1;   /* Log max error */
+
+   /* Buffer information, the buffer size limits the size of the chunks that can
+    * be modified - they must fit (including header and CRC) into the buffer!
+    */
+   size_t                   flush;           /* Count of bytes to flush */
+   size_t                   buffer_count;    /* Bytes in buffer */
+   size_t                   buffer_position; /* Position in buffer */
+   png_byte                 buffer[1024];
+} png_modifier;
+
+/* This returns true if the test should be stopped now because it has already
+ * failed and it is running silently.
+  */
+static int fail(png_modifier *pm)
+{
+   return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
+       (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
+}
+
+static void
+modifier_init(png_modifier *pm)
+{
+   memset(pm, 0, sizeof *pm);
+   store_init(&pm->this);
+   pm->modifications = NULL;
+   pm->state = modifier_start;
+   pm->sbitlow = 1U;
+   pm->ngammas = 0;
+   pm->ngamma_tests = 0;
+   pm->gammas = 0;
+   pm->current_gamma = 0;
+   pm->encodings = 0;
+   pm->nencodings = 0;
+   pm->current_encoding = 0;
+   pm->encoding_counter = 0;
+   pm->encoding_ignored = 0;
+   pm->repeat = 0;
+   pm->test_uses_encoding = 0;
+   pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
+   pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
+   pm->maxcalcG = 0;
+   pm->limit = 4E-3;
+   pm->log8 = pm->log16 = 0; /* Means 'off' */
+   pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
+   pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
+   pm->error_indexed = 0;
+   pm->use_update_info = 0;
+   pm->interlace_type = PNG_INTERLACE_NONE;
+   pm->test_standard = 0;
+   pm->test_size = 0;
+   pm->test_transform = 0;
+#  ifdef PNG_WRITE_tRNS_SUPPORTED
+      pm->test_tRNS = 1;
+#  else
+      pm->test_tRNS = 0;
+#  endif
+   pm->use_input_precision = 0;
+   pm->use_input_precision_sbit = 0;
+   pm->use_input_precision_16to8 = 0;
+   pm->calculations_use_input_precision = 0;
+   pm->assume_16_bit_calculations = 0;
+   pm->test_gamma_threshold = 0;
+   pm->test_gamma_transform = 0;
+   pm->test_gamma_sbit = 0;
+   pm->test_gamma_scale16 = 0;
+   pm->test_gamma_background = 0;
+   pm->test_gamma_alpha_mode = 0;
+   pm->test_gamma_expand16 = 0;
+   pm->test_lbg = 1;
+   pm->test_lbg_gamma_threshold = 1;
+   pm->test_lbg_gamma_transform = 1;
+   pm->test_lbg_gamma_sbit = 1;
+   pm->test_lbg_gamma_composition = 1;
+   pm->test_exhaustive = 0;
+   pm->log = 0;
+
+   /* Rely on the memset for all the other fields - there are no pointers */
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+
+/* This controls use of checks that explicitly know how libpng digitizes the
+ * samples in calculations; setting this circumvents simple error limit checking
+ * in the rgb_to_gray check, replacing it with an exact copy of the libpng 1.5
+ * algorithm.
+ */
+#define DIGITIZE PNG_LIBPNG_VER < 10700
+
+/* If pm->calculations_use_input_precision is set then operations will happen
+ * with the precision of the input, not the precision of the output depth.
+ *
+ * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
+ * bit precision.  This only affects those of the following limits that pertain
+ * to a calculation - not a digitization operation - unless the following API is
+ * called directly.
+ */
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+#if DIGITIZE
+static double digitize(double value, int depth, int do_round)
+{
+   /* 'value' is in the range 0 to 1, the result is the same value rounded to a
+    * multiple of the digitization factor - 8 or 16 bits depending on both the
+    * sample depth and the 'assume' setting.  Digitization is normally by
+    * rounding and 'do_round' should be 1, if it is 0 the digitized value will
+    * be truncated.
+    */
+   unsigned int digitization_factor = (1U << depth) - 1;
+
+   /* Limiting the range is done as a convenience to the caller - it's easier to
+    * do it once here than every time at the call site.
+    */
+   if (value <= 0)
+      value = 0;
+
+   else if (value >= 1)
+      value = 1;
+
+   value *= digitization_factor;
+   if (do_round) value += .5;
+   return floor(value)/digitization_factor;
+}
+#endif
+#endif /* RGB_TO_GRAY */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+static double abserr(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* Absolute error permitted in linear values - affected by the bit depth of
+    * the calculations.
+    */
+   if (pm->assume_16_bit_calculations ||
+      (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+      return pm->maxabs16;
+   else
+      return pm->maxabs8;
+}
+
+static double calcerr(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* Error in the linear composition arithmetic - only relevant when
+    * composition actually happens (0 < alpha < 1).
+    */
+   if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+      return pm->maxcalc16;
+   else if (pm->assume_16_bit_calculations)
+      return pm->maxcalcG;
+   else
+      return pm->maxcalc8;
+}
+
+static double pcerr(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* Percentage error permitted in the linear values.  Note that the specified
+    * value is a percentage but this routine returns a simple number.
+    */
+   if (pm->assume_16_bit_calculations ||
+      (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+      return pm->maxpc16 * .01;
+   else
+      return pm->maxpc8 * .01;
+}
+
+/* Output error - the error in the encoded value.  This is determined by the
+ * digitization of the output so can be +/-0.5 in the actual output value.  In
+ * the expand_16 case with the current code in libpng the expand happens after
+ * all the calculations are done in 8 bit arithmetic, so even though the output
+ * depth is 16 the output error is determined by the 8 bit calculation.
+ *
+ * This limit is not determined by the bit depth of internal calculations.
+ *
+ * The specified parameter does *not* include the base .5 digitization error but
+ * it is added here.
+ */
+static double outerr(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* There is a serious error in the 2 and 4 bit grayscale transform because
+    * the gamma table value (8 bits) is simply shifted, not rounded, so the
+    * error in 4 bit grayscale gamma is up to the value below.  This is a hack
+    * to allow pngvalid to succeed:
+    *
+    * TODO: fix this in libpng
+    */
+   if (out_depth == 2)
+      return .73182-.5;
+
+   if (out_depth == 4)
+      return .90644-.5;
+
+   if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+      return pm->maxout16;
+
+   /* This is the case where the value was calculated at 8-bit precision then
+    * scaled to 16 bits.
+    */
+   else if (out_depth == 16)
+      return pm->maxout8 * 257;
+
+   else
+      return pm->maxout8;
+}
+
+/* This does the same thing as the above however it returns the value to log,
+ * rather than raising a warning.  This is useful for debugging to track down
+ * exactly what set of parameters cause high error values.
+ */
+static double outlog(const png_modifier *pm, int in_depth, int out_depth)
+{
+   /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
+    * and so must be adjusted for low bit depth grayscale:
+    */
+   if (out_depth <= 8)
+   {
+      if (pm->log8 == 0) /* switched off */
+         return 256;
+
+      if (out_depth < 8)
+         return pm->log8 / 255 * ((1<<out_depth)-1);
+
+      return pm->log8;
+   }
+
+   if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
+   {
+      if (pm->log16 == 0)
+         return 65536;
+
+      return pm->log16;
+   }
+
+   /* This is the case where the value was calculated at 8-bit precision then
+    * scaled to 16 bits.
+    */
+   if (pm->log8 == 0)
+      return 65536;
+
+   return pm->log8 * 257;
+}
+
+/* This complements the above by providing the appropriate quantization for the
+ * final value.  Normally this would just be quantization to an integral value,
+ * but in the 8 bit calculation case it's actually quantization to a multiple of
+ * 257!
+ */
+static int output_quantization_factor(const png_modifier *pm, int in_depth,
+   int out_depth)
+{
+   if (out_depth == 16 && in_depth != 16 &&
+      pm->calculations_use_input_precision)
+      return 257;
+   else
+      return 1;
+}
+#endif /* PNG_READ_GAMMA_SUPPORTED */
+
+/* One modification structure must be provided for each chunk to be modified (in
+ * fact more than one can be provided if multiple separate changes are desired
+ * for a single chunk.)  Modifications include adding a new chunk when a
+ * suitable chunk does not exist.
+ *
+ * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
+ * or 'added' as appropriate if the modify_fn returns 1 (true).  If the
+ * modify_fn is NULL the chunk is simply removed.
+ */
+typedef struct png_modification
+{
+   struct png_modification *next;
+   png_uint_32              chunk;
+
+   /* If the following is NULL all matching chunks will be removed: */
+   int                    (*modify_fn)(struct png_modifier *pm,
+                               struct png_modification *me, int add);
+
+   /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
+    * found and modified (and there is a modify_fn) the modify_fn will be called
+    * to add the chunk before the relevant chunk.
+    */
+   png_uint_32              add;
+   unsigned int             modified :1;     /* Chunk was modified */
+   unsigned int             added    :1;     /* Chunk was added */
+   unsigned int             removed  :1;     /* Chunk was removed */
+} png_modification;
+
+static void
+modification_reset(png_modification *pmm)
+{
+   if (pmm != NULL)
+   {
+      pmm->modified = 0;
+      pmm->added = 0;
+      pmm->removed = 0;
+      modification_reset(pmm->next);
+   }
+}
+
+static void
+modification_init(png_modification *pmm)
+{
+   memset(pmm, 0, sizeof *pmm);
+   pmm->next = NULL;
+   pmm->chunk = 0;
+   pmm->modify_fn = NULL;
+   pmm->add = 0;
+   modification_reset(pmm);
+}
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+static void
+modifier_current_encoding(const png_modifier *pm, color_encoding *ce)
+{
+   if (pm->current_encoding != 0)
+      *ce = *pm->current_encoding;
+
+   else
+      memset(ce, 0, sizeof *ce);
+
+   ce->gamma = pm->current_gamma;
+}
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static size_t
+safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
+   const png_modifier *pm)
+{
+   pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
+      pm->current_gamma);
+
+   if (pm->encoding_ignored)
+      pos = safecat(buffer, bufsize, pos, "[overridden]");
+
+   return pos;
+}
+#endif
+
+/* Iterate through the usefully testable color encodings.  An encoding is one
+ * of:
+ *
+ * 1) Nothing (no color space, no gamma).
+ * 2) Just a gamma value from the gamma array (including 1.0)
+ * 3) A color space from the encodings array with the corresponding gamma.
+ * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
+ *
+ * The iterator selects these in turn, the randomizer selects one at random,
+ * which is used depends on the setting of the 'test_exhaustive' flag.  Notice
+ * that this function changes the colour space encoding so it must only be
+ * called on completion of the previous test.  This is what 'modifier_reset'
+ * does, below.
+ *
+ * After the function has been called the 'repeat' flag will still be set; the
+ * caller of modifier_reset must reset it at the start of each run of the test!
+ */
+static unsigned int
+modifier_total_encodings(const png_modifier *pm)
+{
+   return 1 +                 /* (1) nothing */
+      pm->ngammas +           /* (2) gamma values to test */
+      pm->nencodings +        /* (3) total number of encodings */
+      /* The following test only works after the first time through the
+       * png_modifier code because 'bit_depth' is set when the IHDR is read.
+       * modifier_reset, below, preserves the setting until after it has called
+       * the iterate function (also below.)
+       *
+       * For this reason do not rely on this function outside a call to
+       * modifier_reset.
+       */
+      ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
+         pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
+}
+
+static void
+modifier_encoding_iterate(png_modifier *pm)
+{
+   if (!pm->repeat && /* Else something needs the current encoding again. */
+      pm->test_uses_encoding) /* Some transform is encoding dependent */
+   {
+      if (pm->test_exhaustive)
+      {
+         if (++pm->encoding_counter >= modifier_total_encodings(pm))
+            pm->encoding_counter = 0; /* This will stop the repeat */
+      }
+
+      else
+      {
+         /* Not exhaustive - choose an encoding at random; generate a number in
+          * the range 1..(max-1), so the result is always non-zero:
+          */
+         if (pm->encoding_counter == 0)
+            pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
+         else
+            pm->encoding_counter = 0;
+      }
+
+      if (pm->encoding_counter > 0)
+         pm->repeat = 1;
+   }
+
+   else if (!pm->repeat)
+      pm->encoding_counter = 0;
+}
+
+static void
+modifier_reset(png_modifier *pm)
+{
+   store_read_reset(&pm->this);
+   pm->limit = 4E-3;
+   pm->pending_len = pm->pending_chunk = 0;
+   pm->flush = pm->buffer_count = pm->buffer_position = 0;
+   pm->modifications = NULL;
+   pm->state = modifier_start;
+   modifier_encoding_iterate(pm);
+   /* The following must be set in the next run.  In particular
+    * test_uses_encodings must be set in the _ini function of each transform
+    * that looks at the encodings.  (Not the 'add' function!)
+    */
+   pm->test_uses_encoding = 0;
+   pm->current_gamma = 0;
+   pm->current_encoding = 0;
+   pm->encoding_ignored = 0;
+   /* These only become value after IHDR is read: */
+   pm->bit_depth = pm->colour_type = 0;
+}
+
+/* The following must be called before anything else to get the encoding set up
+ * on the modifier.  In particular it must be called before the transform init
+ * functions are called.
+ */
+static void
+modifier_set_encoding(png_modifier *pm)
+{
+   /* Set the encoding to the one specified by the current encoding counter,
+    * first clear out all the settings - this corresponds to an encoding_counter
+    * of 0.
+    */
+   pm->current_gamma = 0;
+   pm->current_encoding = 0;
+   pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
+
+   /* Now, if required, set the gamma and encoding fields. */
+   if (pm->encoding_counter > 0)
+   {
+      /* The gammas[] array is an array of screen gammas, not encoding gammas,
+       * so we need the inverse:
+       */
+      if (pm->encoding_counter <= pm->ngammas)
+         pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
+
+      else
+      {
+         unsigned int i = pm->encoding_counter - pm->ngammas;
+
+         if (i >= pm->nencodings)
+         {
+            i %= pm->nencodings;
+            pm->current_gamma = 1; /* Linear, only in the 16 bit case */
+         }
+
+         else
+            pm->current_gamma = pm->encodings[i].gamma;
+
+         pm->current_encoding = pm->encodings + i;
+      }
+   }
+}
+
+/* Enquiry functions to find out what is set.  Notice that there is an implicit
+ * assumption below that the first encoding in the list is the one for sRGB.
+ */
+static int
+modifier_color_encoding_is_sRGB(const png_modifier *pm)
+{
+   return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
+      pm->current_encoding->gamma == pm->current_gamma;
+}
+
+static int
+modifier_color_encoding_is_set(const png_modifier *pm)
+{
+   return pm->current_gamma != 0;
+}
+
+/* The guts of modification are performed during a read. */
+static void
+modifier_crc(png_bytep buffer)
+{
+   /* Recalculate the chunk CRC - a complete chunk must be in
+    * the buffer, at the start.
+    */
+   uInt datalen = png_get_uint_32(buffer);
+   uLong crc = crc32(0, buffer+4, datalen+4);
+   /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
+    */
+   png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
+}
+
+static void
+modifier_setbuffer(png_modifier *pm)
+{
+   modifier_crc(pm->buffer);
+   pm->buffer_count = png_get_uint_32(pm->buffer)+12;
+   pm->buffer_position = 0;
+}
+
+/* Separate the callback into the actual implementation (which is passed the
+ * png_modifier explicitly) and the callback, which gets the modifier from the
+ * png_struct.
+ */
+static void
+modifier_read_imp(png_modifier *pm, png_bytep pb, size_t st)
+{
+   while (st > 0)
+   {
+      size_t cb;
+      png_uint_32 len, chunk;
+      png_modification *mod;
+
+      if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
+      {
+         static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
+         case modifier_start:
+            store_read_chunk(&pm->this, pm->buffer, 8, 8); /* signature. */
+            pm->buffer_count = 8;
+            pm->buffer_position = 0;
+
+            if (memcmp(pm->buffer, sign, 8) != 0)
+               png_error(pm->this.pread, "invalid PNG file signature");
+            pm->state = modifier_signature;
+            break;
+
+         case modifier_signature:
+            store_read_chunk(&pm->this, pm->buffer, 13+12, 13+12); /* IHDR */
+            pm->buffer_count = 13+12;
+            pm->buffer_position = 0;
+
+            if (png_get_uint_32(pm->buffer) != 13 ||
+                png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
+               png_error(pm->this.pread, "invalid IHDR");
+
+            /* Check the list of modifiers for modifications to the IHDR. */
+            mod = pm->modifications;
+            while (mod != NULL)
+            {
+               if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
+                   (*mod->modify_fn)(pm, mod, 0))
+                  {
+                  mod->modified = 1;
+                  modifier_setbuffer(pm);
+                  }
+
+               /* Ignore removal or add if IHDR! */
+               mod = mod->next;
+            }
+
+            /* Cache information from the IHDR (the modified one.) */
+            pm->bit_depth = pm->buffer[8+8];
+            pm->colour_type = pm->buffer[8+8+1];
+
+            pm->state = modifier_IHDR;
+            pm->flush = 0;
+            break;
+
+         case modifier_IHDR:
+         default:
+            /* Read a new chunk and process it until we see PLTE, IDAT or
+             * IEND.  'flush' indicates that there is still some data to
+             * output from the preceding chunk.
+             */
+            if ((cb = pm->flush) > 0)
+            {
+               if (cb > st) cb = st;
+               pm->flush -= cb;
+               store_read_chunk(&pm->this, pb, cb, cb);
+               pb += cb;
+               st -= cb;
+               if (st == 0) return;
+            }
+
+            /* No more bytes to flush, read a header, or handle a pending
+             * chunk.
+             */
+            if (pm->pending_chunk != 0)
+            {
+               png_save_uint_32(pm->buffer, pm->pending_len);
+               png_save_uint_32(pm->buffer+4, pm->pending_chunk);
+               pm->pending_len = 0;
+               pm->pending_chunk = 0;
+            }
+            else
+               store_read_chunk(&pm->this, pm->buffer, 8, 8);
+
+            pm->buffer_count = 8;
+            pm->buffer_position = 0;
+
+            /* Check for something to modify or a terminator chunk. */
+            len = png_get_uint_32(pm->buffer);
+            chunk = png_get_uint_32(pm->buffer+4);
+
+            /* Terminators first, they may have to be delayed for added
+             * chunks
+             */
+            if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
+                chunk == CHUNK_IEND)
+            {
+               mod = pm->modifications;
+
+               while (mod != NULL)
+               {
+                  if ((mod->add == chunk ||
+                      (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
+                      mod->modify_fn != NULL && !mod->modified && !mod->added)
+                  {
+                     /* Regardless of what the modify function does do not run
+                      * this again.
+                      */
+                     mod->added = 1;
+
+                     if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
+                     {
+                        /* Reset the CRC on a new chunk */
+                        if (pm->buffer_count > 0)
+                           modifier_setbuffer(pm);
+
+                        else
+                           {
+                           pm->buffer_position = 0;
+                           mod->removed = 1;
+                           }
+
+                        /* The buffer has been filled with something (we assume)
+                         * so output this.  Pend the current chunk.
+                         */
+                        pm->pending_len = len;
+                        pm->pending_chunk = chunk;
+                        break; /* out of while */
+                     }
+                  }
+
+                  mod = mod->next;
+               }
+
+               /* Don't do any further processing if the buffer was modified -
+                * otherwise the code will end up modifying a chunk that was
+                * just added.
+                */
+               if (mod != NULL)
+                  break; /* out of switch */
+            }
+
+            /* If we get to here then this chunk may need to be modified.  To
+             * do this it must be less than 1024 bytes in total size, otherwise
+             * it just gets flushed.
+             */
+            if (len+12 <= sizeof pm->buffer)
+            {
+               size_t s = len+12-pm->buffer_count;
+               store_read_chunk(&pm->this, pm->buffer+pm->buffer_count, s, s);
+               pm->buffer_count = len+12;
+
+               /* Check for a modification, else leave it be. */
+               mod = pm->modifications;
+               while (mod != NULL)
+               {
+                  if (mod->chunk == chunk)
+                  {
+                     if (mod->modify_fn == NULL)
+                     {
+                        /* Remove this chunk */
+                        pm->buffer_count = pm->buffer_position = 0;
+                        mod->removed = 1;
+                        break; /* Terminate the while loop */
+                     }
+
+                     else if ((*mod->modify_fn)(pm, mod, 0))
+                     {
+                        mod->modified = 1;
+                        /* The chunk may have been removed: */
+                        if (pm->buffer_count == 0)
+                        {
+                           pm->buffer_position = 0;
+                           break;
+                        }
+                        modifier_setbuffer(pm);
+                     }
+                  }
+
+                  mod = mod->next;
+               }
+            }
+
+            else
+               pm->flush = len+12 - pm->buffer_count; /* data + crc */
+
+            /* Take the data from the buffer (if there is any). */
+            break;
+      }
+
+      /* Here to read from the modifier buffer (not directly from
+       * the store, as in the flush case above.)
+       */
+      cb = pm->buffer_count - pm->buffer_position;
+
+      if (cb > st)
+         cb = st;
+
+      memcpy(pb, pm->buffer + pm->buffer_position, cb);
+      st -= cb;
+      pb += cb;
+      pm->buffer_position += cb;
+   }
+}
+
+/* The callback: */
+static void PNGCBAPI
+modifier_read(png_structp ppIn, png_bytep pb, size_t st)
+{
+   png_const_structp pp = ppIn;
+   png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
+
+   if (pm == NULL || pm->this.pread != pp)
+      png_error(pp, "bad modifier_read call");
+
+   modifier_read_imp(pm, pb, st);
+}
+
+/* Like store_progressive_read but the data is getting changed as we go so we
+ * need a local buffer.
+ */
+static void
+modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
+{
+   if (pm->this.pread != pp || pm->this.current == NULL ||
+       pm->this.next == NULL)
+      png_error(pp, "store state damaged (progressive)");
+
+   /* This is another Horowitz and Hill random noise generator.  In this case
+    * the aim is to stress the progressive reader with truly horrible variable
+    * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
+    * is generated.  We could probably just count from 1 to 32767 and get as
+    * good a result.
+    */
+   for (;;)
+   {
+      static png_uint_32 noise = 1;
+      size_t cb, cbAvail;
+      png_byte buffer[512];
+
+      /* Generate 15 more bits of stuff: */
+      noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
+      cb = noise & 0x1ff;
+
+      /* Check that this number of bytes are available (in the current buffer.)
+       * (This doesn't quite work - the modifier might delete a chunk; unlikely
+       * but possible, it doesn't happen at present because the modifier only
+       * adds chunks to standard images.)
+       */
+      cbAvail = store_read_buffer_avail(&pm->this);
+      if (pm->buffer_count > pm->buffer_position)
+         cbAvail += pm->buffer_count - pm->buffer_position;
+
+      if (cb > cbAvail)
+      {
+         /* Check for EOF: */
+         if (cbAvail == 0)
+            break;
+
+         cb = cbAvail;
+      }
+
+      modifier_read_imp(pm, buffer, cb);
+      png_process_data(pp, pi, buffer, cb);
+   }
+
+   /* Check the invariants at the end (if this fails it's a problem in this
+    * file!)
+    */
+   if (pm->buffer_count > pm->buffer_position ||
+       pm->this.next != &pm->this.current->data ||
+       pm->this.readpos < pm->this.current->datacount)
+      png_error(pp, "progressive read implementation error");
+}
+
+/* Set up a modifier. */
+static png_structp
+set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
+    const char *name)
+{
+   /* Do this first so that the modifier fields are cleared even if an error
+    * happens allocating the png_struct.  No allocation is done here so no
+    * cleanup is required.
+    */
+   pm->state = modifier_start;
+   pm->bit_depth = 0;
+   pm->colour_type = 255;
+
+   pm->pending_len = 0;
+   pm->pending_chunk = 0;
+   pm->flush = 0;
+   pm->buffer_count = 0;
+   pm->buffer_position = 0;
+
+   return set_store_for_read(&pm->this, ppi, id, name);
+}
+
+
+/******************************** MODIFICATIONS *******************************/
+/* Standard modifications to add chunks.  These do not require the _SUPPORTED
+ * macros because the chunks can be there regardless of whether this specific
+ * libpng supports them.
+ */
+typedef struct gama_modification
+{
+   png_modification this;
+   png_fixed_point  gamma;
+} gama_modification;
+
+static int
+gama_modify(png_modifier *pm, png_modification *me, int add)
+{
+   UNUSED(add)
+   /* This simply dumps the given gamma value into the buffer. */
+   png_save_uint_32(pm->buffer, 4);
+   png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
+   png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
+   return 1;
+}
+
+static void
+gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
+{
+   double g;
+
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_gAMA;
+   me->this.modify_fn = gama_modify;
+   me->this.add = CHUNK_PLTE;
+   g = fix(gammad);
+   me->gamma = (png_fixed_point)g;
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+
+typedef struct chrm_modification
+{
+   png_modification          this;
+   const color_encoding *encoding;
+   png_fixed_point           wx, wy, rx, ry, gx, gy, bx, by;
+} chrm_modification;
+
+static int
+chrm_modify(png_modifier *pm, png_modification *me, int add)
+{
+   UNUSED(add)
+   /* As with gAMA this just adds the required cHRM chunk to the buffer. */
+   png_save_uint_32(pm->buffer   , 32);
+   png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
+   png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
+   png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
+   png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
+   png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
+   png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
+   png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
+   png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
+   png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
+   return 1;
+}
+
+static void
+chrm_modification_init(chrm_modification *me, png_modifier *pm,
+   const color_encoding *encoding)
+{
+   CIE_color white = white_point(encoding);
+
+   /* Original end points: */
+   me->encoding = encoding;
+
+   /* Chromaticities (in fixed point): */
+   me->wx = fix(chromaticity_x(white));
+   me->wy = fix(chromaticity_y(white));
+
+   me->rx = fix(chromaticity_x(encoding->red));
+   me->ry = fix(chromaticity_y(encoding->red));
+   me->gx = fix(chromaticity_x(encoding->green));
+   me->gy = fix(chromaticity_y(encoding->green));
+   me->bx = fix(chromaticity_x(encoding->blue));
+   me->by = fix(chromaticity_y(encoding->blue));
+
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_cHRM;
+   me->this.modify_fn = chrm_modify;
+   me->this.add = CHUNK_PLTE;
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+
+typedef struct srgb_modification
+{
+   png_modification this;
+   png_byte         intent;
+} srgb_modification;
+
+static int
+srgb_modify(png_modifier *pm, png_modification *me, int add)
+{
+   UNUSED(add)
+   /* As above, ignore add and just make a new chunk */
+   png_save_uint_32(pm->buffer, 1);
+   png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
+   pm->buffer[8] = ((srgb_modification*)me)->intent;
+   return 1;
+}
+
+static void
+srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
+{
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_sBIT;
+
+   if (intent <= 3) /* if valid, else *delete* sRGB chunks */
+   {
+      me->this.modify_fn = srgb_modify;
+      me->this.add = CHUNK_PLTE;
+      me->intent = intent;
+   }
+
+   else
+   {
+      me->this.modify_fn = 0;
+      me->this.add = 0;
+      me->intent = 0;
+   }
+
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+typedef struct sbit_modification
+{
+   png_modification this;
+   png_byte         sbit;
+} sbit_modification;
+
+static int
+sbit_modify(png_modifier *pm, png_modification *me, int add)
+{
+   png_byte sbit = ((sbit_modification*)me)->sbit;
+   if (pm->bit_depth > sbit)
+   {
+      int cb = 0;
+      switch (pm->colour_type)
+      {
+         case 0:
+            cb = 1;
+            break;
+
+         case 2:
+         case 3:
+            cb = 3;
+            break;
+
+         case 4:
+            cb = 2;
+            break;
+
+         case 6:
+            cb = 4;
+            break;
+
+         default:
+            png_error(pm->this.pread,
+               "unexpected colour type in sBIT modification");
+      }
+
+      png_save_uint_32(pm->buffer, cb);
+      png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
+
+      while (cb > 0)
+         (pm->buffer+8)[--cb] = sbit;
+
+      return 1;
+   }
+   else if (!add)
+   {
+      /* Remove the sBIT chunk */
+      pm->buffer_count = pm->buffer_position = 0;
+      return 1;
+   }
+   else
+      return 0; /* do nothing */
+}
+
+static void
+sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
+{
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_sBIT;
+   me->this.modify_fn = sbit_modify;
+   me->this.add = CHUNK_PLTE;
+   me->sbit = sbit;
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+#endif /* PNG_READ_GAMMA_SUPPORTED */
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+/***************************** STANDARD PNG FILES *****************************/
+/* Standard files - write and save standard files. */
+/* There are two basic forms of standard images.  Those which attempt to have
+ * all the possible pixel values (not possible for 16bpp images, but a range of
+ * values are produced) and those which have a range of image sizes.  The former
+ * are used for testing transforms, in particular gamma correction and bit
+ * reduction and increase.  The latter are reserved for testing the behavior of
+ * libpng with respect to 'odd' image sizes - particularly small images where
+ * rows become 1 byte and interlace passes disappear.
+ *
+ * The first, most useful, set are the 'transform' images, the second set of
+ * small images are the 'size' images.
+ *
+ * The transform files are constructed with rows which fit into a 1024 byte row
+ * buffer.  This makes allocation easier below.  Further regardless of the file
+ * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
+ *
+ * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
+ * and with an ID derived from the colour type, bit depth and interlace type
+ * as above (FILEID).  The width (128) and height (variable) are not stored in
+ * the FILEID - instead the fields are set to 0, indicating a transform file.
+ *
+ * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
+ * a maximum width of 16 pixels (for the 64bpp case.)  They also have a maximum
+ * height of 16 rows.  The width and height are stored in the FILEID and, being
+ * non-zero, indicate a size file.
+ *
+ * Because the PNG filter code is typically the largest CPU consumer within
+ * libpng itself there is a tendency to attempt to optimize it.  This results in
+ * special case code which needs to be validated.  To cause this to happen the
+ * 'size' images are made to use each possible filter, in so far as this is
+ * possible for smaller images.
+ *
+ * For palette image (colour type 3) multiple transform images are stored with
+ * the same bit depth to allow testing of more colour combinations -
+ * particularly important for testing the gamma code because libpng uses a
+ * different code path for palette images.  For size images a single palette is
+ * used.
+ */
+
+/* Make a 'standard' palette.  Because there are only 256 entries in a palette
+ * (maximum) this actually makes a random palette in the hope that enough tests
+ * will catch enough errors.  (Note that the same palette isn't produced every
+ * time for the same test - it depends on what previous tests have been run -
+ * but a given set of arguments to pngvalid will always produce the same palette
+ * at the same test!  This is why pseudo-random number generators are useful for
+ * testing.)
+ *
+ * The store must be open for write when this is called, otherwise an internal
+ * error will occur.  This routine contains its own magic number seed, so the
+ * palettes generated don't change if there are intervening errors (changing the
+ * calls to the store_mark seed.)
+ */
+static store_palette_entry *
+make_standard_palette(png_store* ps, int npalette, int do_tRNS)
+{
+   static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
+
+   int i = 0;
+   png_byte values[256][4];
+
+   /* Always put in black and white plus the six primary and secondary colors.
+    */
+   for (; i<8; ++i)
+   {
+      values[i][1] = (png_byte)((i&1) ? 255U : 0U);
+      values[i][2] = (png_byte)((i&2) ? 255U : 0U);
+      values[i][3] = (png_byte)((i&4) ? 255U : 0U);
+   }
+
+   /* Then add 62 grays (one quarter of the remaining 256 slots). */
+   {
+      int j = 0;
+      png_byte random_bytes[4];
+      png_byte need[256];
+
+      need[0] = 0; /*got black*/
+      memset(need+1, 1, (sizeof need)-2); /*need these*/
+      need[255] = 0; /*but not white*/
+
+      while (i<70)
+      {
+         png_byte b;
+
+         if (j==0)
+         {
+            make_four_random_bytes(palette_seed, random_bytes);
+            j = 4;
+         }
+
+         b = random_bytes[--j];
+         if (need[b])
+         {
+            values[i][1] = b;
+            values[i][2] = b;
+            values[i++][3] = b;
+         }
+      }
+   }
+
+   /* Finally add 192 colors at random - don't worry about matches to things we
+    * already have, chance is less than 1/65536.  Don't worry about grays,
+    * chance is the same, so we get a duplicate or extra gray less than 1 time
+    * in 170.
+    */
+   for (; i<256; ++i)
+      make_four_random_bytes(palette_seed, values[i]);
+
+   /* Fill in the alpha values in the first byte.  Just use all possible values
+    * (0..255) in an apparently random order:
+    */
+   {
+      store_palette_entry *palette;
+      png_byte selector[4];
+
+      make_four_random_bytes(palette_seed, selector);
+
+      if (do_tRNS)
+         for (i=0; i<256; ++i)
+            values[i][0] = (png_byte)(i ^ selector[0]);
+
+      else
+         for (i=0; i<256; ++i)
+            values[i][0] = 255; /* no transparency/tRNS chunk */
+
+      /* 'values' contains 256 ARGB values, but we only need 'npalette'.
+       * 'npalette' will always be a power of 2: 2, 4, 16 or 256.  In the low
+       * bit depth cases select colors at random, else it is difficult to have
+       * a set of low bit depth palette test with any chance of a reasonable
+       * range of colors.  Do this by randomly permuting values into the low
+       * 'npalette' entries using an XOR mask generated here.  This also
+       * permutes the npalette == 256 case in a potentially useful way (there is
+       * no relationship between palette index and the color value therein!)
+       */
+      palette = store_write_palette(ps, npalette);
+
+      for (i=0; i<npalette; ++i)
+      {
+         palette[i].alpha = values[i ^ selector[1]][0];
+         palette[i].red   = values[i ^ selector[1]][1];
+         palette[i].green = values[i ^ selector[1]][2];
+         palette[i].blue  = values[i ^ selector[1]][3];
+      }
+
+      return palette;
+   }
+}
+
+/* Initialize a standard palette on a write stream.  The 'do_tRNS' argument
+ * indicates whether or not to also set the tRNS chunk.
+ */
+/* TODO: the png_structp here can probably be 'const' in the future */
+static void
+init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
+   int do_tRNS)
+{
+   store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
+
+   {
+      int i;
+      png_color palette[256];
+
+      /* Set all entries to detect overread errors. */
+      for (i=0; i<npalette; ++i)
+      {
+         palette[i].red = ppal[i].red;
+         palette[i].green = ppal[i].green;
+         palette[i].blue = ppal[i].blue;
+      }
+
+      /* Just in case fill in the rest with detectable values: */
+      for (; i<256; ++i)
+         palette[i].red = palette[i].green = palette[i].blue = 42;
+
+      png_set_PLTE(pp, pi, palette, npalette);
+   }
+
+   if (do_tRNS)
+   {
+      int i, j;
+      png_byte tRNS[256];
+
+      /* Set all the entries, but skip trailing opaque entries */
+      for (i=j=0; i<npalette; ++i)
+         if ((tRNS[i] = ppal[i].alpha) < 255)
+            j = i+1;
+
+      /* Fill in the remainder with a detectable value: */
+      for (; i<256; ++i)
+         tRNS[i] = 24;
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+      if (j > 0)
+         png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
+#endif
+   }
+}
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+static void
+set_random_tRNS(png_structp pp, png_infop pi, png_byte colour_type,
+   int bit_depth)
+{
+   /* To make this useful the tRNS color needs to match at least one pixel.
+    * Random values are fine for gray, including the 16-bit case where we know
+    * that the test image contains all the gray values.  For RGB we need more
+    * method as only 65536 different RGB values are generated.
+    */
+   png_color_16 tRNS;
+   png_uint_16 mask = (png_uint_16)((1U << bit_depth)-1);
+
+   R8(tRNS); /* makes unset fields random */
+
+   if (colour_type & 2/*RGB*/)
+   {
+      if (bit_depth == 8)
+      {
+         tRNS.red = random_u16();
+         tRNS.green = random_u16();
+         tRNS.blue = tRNS.red ^ tRNS.green;
+         tRNS.red &= mask;
+         tRNS.green &= mask;
+         tRNS.blue &= mask;
+      }
+
+      else /* bit_depth == 16 */
+      {
+         tRNS.red = random_u16();
+         tRNS.green = (png_uint_16)(tRNS.red * 257);
+         tRNS.blue = (png_uint_16)(tRNS.green * 17);
+      }
+   }
+
+   else
+   {
+      tRNS.gray = random_u16();
+      tRNS.gray &= mask;
+   }
+
+   png_set_tRNS(pp, pi, NULL, 0, &tRNS);
+}
+#endif
+
+/* The number of passes is related to the interlace type. There was no libpng
+ * API to determine this prior to 1.5, so we need an inquiry function:
+ */
+static int
+npasses_from_interlace_type(png_const_structp pp, int interlace_type)
+{
+   switch (interlace_type)
+   {
+   default:
+      png_error(pp, "invalid interlace type");
+
+   case PNG_INTERLACE_NONE:
+      return 1;
+
+   case PNG_INTERLACE_ADAM7:
+      return PNG_INTERLACE_ADAM7_PASSES;
+   }
+}
+
+static unsigned int
+bit_size(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+   switch (colour_type)
+   {
+      default: png_error(pp, "invalid color type");
+
+      case 0:  return bit_depth;
+
+      case 2:  return 3*bit_depth;
+
+      case 3:  return bit_depth;
+
+      case 4:  return 2*bit_depth;
+
+      case 6:  return 4*bit_depth;
+   }
+}
+
+#define TRANSFORM_WIDTH  128U
+#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
+#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
+#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
+#define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
+
+static size_t
+transform_rowsize(png_const_structp pp, png_byte colour_type,
+   png_byte bit_depth)
+{
+   return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
+}
+
+/* transform_width(pp, colour_type, bit_depth) current returns the same number
+ * every time, so just use a macro:
+ */
+#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
+
+static png_uint_32
+transform_height(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+   switch (bit_size(pp, colour_type, bit_depth))
+   {
+      case 1:
+      case 2:
+      case 4:
+         return 1;   /* Total of 128 pixels */
+
+      case 8:
+         return 2;   /* Total of 256 pixels/bytes */
+
+      case 16:
+         return 512; /* Total of 65536 pixels */
+
+      case 24:
+      case 32:
+         return 512; /* 65536 pixels */
+
+      case 48:
+      case 64:
+         return 2048;/* 4 x 65536 pixels. */
+#        define TRANSFORM_HEIGHTMAX 2048
+
+      default:
+         return 0;   /* Error, will be caught later */
+   }
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* The following can only be defined here, now we have the definitions
+ * of the transform image sizes.
+ */
+static png_uint_32
+standard_width(png_const_structp pp, png_uint_32 id)
+{
+   png_uint_32 width = WIDTH_FROM_ID(id);
+   UNUSED(pp)
+
+   if (width == 0)
+      width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+
+   return width;
+}
+
+static png_uint_32
+standard_height(png_const_structp pp, png_uint_32 id)
+{
+   png_uint_32 height = HEIGHT_FROM_ID(id);
+
+   if (height == 0)
+      height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+
+   return height;
+}
+
+static png_uint_32
+standard_rowsize(png_const_structp pp, png_uint_32 id)
+{
+   png_uint_32 width = standard_width(pp, id);
+
+   /* This won't overflow: */
+   width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+   return (width + 7) / 8;
+}
+#endif /* PNG_READ_SUPPORTED */
+
+static void
+transform_row(png_const_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
+   png_byte colour_type, png_byte bit_depth, png_uint_32 y)
+{
+   png_uint_32 v = y << 7;
+   png_uint_32 i = 0;
+
+   switch (bit_size(pp, colour_type, bit_depth))
+   {
+      case 1:
+         while (i<128/8) buffer[i] = (png_byte)(v & 0xff), v += 17, ++i;
+         return;
+
+      case 2:
+         while (i<128/4) buffer[i] = (png_byte)(v & 0xff), v += 33, ++i;
+         return;
+
+      case 4:
+         while (i<128/2) buffer[i] = (png_byte)(v & 0xff), v += 65, ++i;
+         return;
+
+      case 8:
+         /* 256 bytes total, 128 bytes in each row set as follows: */
+         while (i<128) buffer[i] = (png_byte)(v & 0xff), ++v, ++i;
+         return;
+
+      case 16:
+         /* Generate all 65536 pixel values in order, which includes the 8 bit
+          * GA case as well as the 16 bit G case.
+          */
+         while (i<128)
+         {
+            buffer[2*i] = (png_byte)((v>>8) & 0xff);
+            buffer[2*i+1] = (png_byte)(v & 0xff);
+            ++v;
+            ++i;
+         }
+
+         return;
+
+      case 24:
+         /* 65535 pixels, but rotate the values. */
+         while (i<128)
+         {
+            /* Three bytes per pixel, r, g, b, make b by r^g */
+            buffer[3*i+0] = (png_byte)((v >> 8) & 0xff);
+            buffer[3*i+1] = (png_byte)(v & 0xff);
+            buffer[3*i+2] = (png_byte)(((v >> 8) ^ v) & 0xff);
+            ++v;
+            ++i;
+         }
+
+         return;
+
+      case 32:
+         /* 65535 pixels, r, g, b, a; just replicate */
+         while (i<128)
+         {
+            buffer[4*i+0] = (png_byte)((v >> 8) & 0xff);
+            buffer[4*i+1] = (png_byte)(v & 0xff);
+            buffer[4*i+2] = (png_byte)((v >> 8) & 0xff);
+            buffer[4*i+3] = (png_byte)(v & 0xff);
+            ++v;
+            ++i;
+         }
+
+         return;
+
+      case 48:
+         /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
+          * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
+          */
+         while (i<128)
+         {
+            png_uint_32 t = v++;
+            buffer[6*i+0] = (png_byte)((t >> 8) & 0xff);
+            buffer[6*i+1] = (png_byte)(t & 0xff);
+            t *= 257;
+            buffer[6*i+2] = (png_byte)((t >> 8) & 0xff);
+            buffer[6*i+3] = (png_byte)(t & 0xff);
+            t *= 17;
+            buffer[6*i+4] = (png_byte)((t >> 8) & 0xff);
+            buffer[6*i+5] = (png_byte)(t & 0xff);
+            ++i;
+         }
+
+         return;
+
+      case 64:
+         /* As above in the 32 bit case. */
+         while (i<128)
+         {
+            png_uint_32 t = v++;
+            buffer[8*i+0] = (png_byte)((t >> 8) & 0xff);
+            buffer[8*i+1] = (png_byte)(t & 0xff);
+            buffer[8*i+4] = (png_byte)((t >> 8) & 0xff);
+            buffer[8*i+5] = (png_byte)(t & 0xff);
+            t *= 257;
+            buffer[8*i+2] = (png_byte)((t >> 8) & 0xff);
+            buffer[8*i+3] = (png_byte)(t & 0xff);
+            buffer[8*i+6] = (png_byte)((t >> 8) & 0xff);
+            buffer[8*i+7] = (png_byte)(t & 0xff);
+            ++i;
+         }
+         return;
+
+      default:
+         break;
+   }
+
+   png_error(pp, "internal error");
+}
+
+/* This is just to do the right cast - could be changed to a function to check
+ * 'bd' but there isn't much point.
+ */
+#define DEPTH(bd) ((png_byte)(1U << (bd)))
+
+/* This is just a helper for compiling on minimal systems with no write
+ * interlacing support.  If there is no write interlacing we can't generate test
+ * cases with interlace:
+ */
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+#  define INTERLACE_LAST PNG_INTERLACE_LAST
+#  define check_interlace_type(type) ((void)(type))
+#  define set_write_interlace_handling(pp,type) png_set_interlace_handling(pp)
+#  define do_own_interlace 0
+#elif PNG_LIBPNG_VER < 10700
+#  define set_write_interlace_handling(pp,type) (1)
+static void
+check_interlace_type(int const interlace_type)
+{
+   /* Prior to 1.7.0 libpng does not support the write of an interlaced image
+    * unless PNG_WRITE_INTERLACING_SUPPORTED, even with do_interlace so the
+    * code here does the pixel interlace itself, so:
+    */
+   if (interlace_type != PNG_INTERLACE_NONE)
+   {
+      /* This is an internal error - --interlace tests should be skipped, not
+       * attempted.
+       */
+      fprintf(stderr, "pngvalid: no interlace support\n");
+      exit(99);
+   }
+}
+#  define INTERLACE_LAST (PNG_INTERLACE_NONE+1)
+#  define do_own_interlace 0
+#else /* libpng 1.7+ */
+#  define set_write_interlace_handling(pp,type)\
+      npasses_from_interlace_type(pp,type)
+#  define check_interlace_type(type) ((void)(type))
+#  define INTERLACE_LAST PNG_INTERLACE_LAST
+#  define do_own_interlace 1
+#endif /* WRITE_INTERLACING tests */
+
+#if PNG_LIBPNG_VER >= 10700 || defined PNG_WRITE_INTERLACING_SUPPORTED
+#   define CAN_WRITE_INTERLACE 1
+#else
+#   define CAN_WRITE_INTERLACE 0
+#endif
+
+/* Do the same thing for read interlacing; this controls whether read tests do
+ * their own de-interlace or use libpng.
+ */
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+#  define do_read_interlace 0
+#else /* no libpng read interlace support */
+#  define do_read_interlace 1
+#endif
+/* The following two routines use the PNG interlace support macros from
+ * png.h to interlace or deinterlace rows.
+ */
+static void
+interlace_row(png_bytep buffer, png_const_bytep imageRow,
+   unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
+{
+   png_uint_32 xin, xout, xstep;
+
+   /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
+    * code is presented this way to make it easier to understand.  In practice
+    * consult the code in the libpng source to see other ways of doing this.
+    *
+    * It is OK for buffer and imageRow to be identical, because 'xin' moves
+    * faster than 'xout' and we copy up.
+    */
+   xin = PNG_PASS_START_COL(pass);
+   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
+
+   for (xout=0; xin<w; xin+=xstep)
+   {
+      pixel_copy(buffer, xout, imageRow, xin, pixel_size, littleendian);
+      ++xout;
+   }
+}
+
+#ifdef PNG_READ_SUPPORTED
+static void
+deinterlace_row(png_bytep buffer, png_const_bytep row,
+   unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
+{
+   /* The inverse of the above, 'row' is part of row 'y' of the output image,
+    * in 'buffer'.  The image is 'w' wide and this is pass 'pass', distribute
+    * the pixels of row into buffer and return the number written (to allow
+    * this to be checked).
+    */
+   png_uint_32 xin, xout, xstep;
+
+   xout = PNG_PASS_START_COL(pass);
+   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
+
+   for (xin=0; xout<w; xout+=xstep)
+   {
+      pixel_copy(buffer, xout, row, xin, pixel_size, littleendian);
+      ++xin;
+   }
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* Make a standardized image given an image colour type, bit depth and
+ * interlace type.  The standard images have a very restricted range of
+ * rows and heights and are used for testing transforms rather than image
+ * layout details.  See make_size_images below for a way to make images
+ * that test odd sizes along with the libpng interlace handling.
+ */
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+static void
+choose_random_filter(png_structp pp, int start)
+{
+   /* Choose filters randomly except that on the very first row ensure that
+    * there is at least one previous row filter.
+    */
+   int filters = PNG_ALL_FILTERS & random_mod(256U);
+
+   /* There may be no filters; skip the setting. */
+   if (filters != 0)
+   {
+      if (start && filters < PNG_FILTER_UP)
+         filters |= PNG_FILTER_UP;
+
+      png_set_filter(pp, 0/*method*/, filters);
+   }
+}
+#else /* !WRITE_FILTER */
+#  define choose_random_filter(pp, start) ((void)0)
+#endif /* !WRITE_FILTER */
+
+static void
+make_transform_image(png_store* const ps, png_byte const colour_type,
+    png_byte const bit_depth, unsigned int palette_number,
+    int interlace_type, png_const_charp name)
+{
+   context(ps, fault);
+
+   check_interlace_type(interlace_type);
+
+   Try
+   {
+      png_infop pi;
+      png_structp pp = set_store_for_write(ps, &pi, name);
+      png_uint_32 h, w;
+
+      /* In the event of a problem return control to the Catch statement below
+       * to do the clean up - it is not possible to 'return' directly from a Try
+       * block.
+       */
+      if (pp == NULL)
+         Throw ps;
+
+      w = transform_width(pp, colour_type, bit_depth);
+      h = transform_height(pp, colour_type, bit_depth);
+
+      png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
+         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+#ifdef PNG_TEXT_SUPPORTED
+#  if defined(PNG_READ_zTXt_SUPPORTED) && defined(PNG_WRITE_zTXt_SUPPORTED)
+#     define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_zTXt
+#  else
+#     define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_NONE
+#  endif
+      {
+         static char key[] = "image name"; /* must be writeable */
+         size_t pos;
+         png_text text;
+         char copy[FILE_NAME_SIZE];
+
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = TEXT_COMPRESSION;
+         text.key = key;
+         /* Yuck: the text must be writable! */
+         pos = safecat(copy, sizeof copy, 0, ps->wname);
+         text.text = copy;
+         text.text_length = pos;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+
+      if (colour_type == 3) /* palette */
+         init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
+
+#     ifdef PNG_WRITE_tRNS_SUPPORTED
+         else if (palette_number)
+            set_random_tRNS(pp, pi, colour_type, bit_depth);
+#     endif
+
+      png_write_info(pp, pi);
+
+      if (png_get_rowbytes(pp, pi) !=
+          transform_rowsize(pp, colour_type, bit_depth))
+         png_error(pp, "transform row size incorrect");
+
+      else
+      {
+         /* Somewhat confusingly this must be called *after* png_write_info
+          * because if it is called before, the information in *pp has not been
+          * updated to reflect the interlaced image.
+          */
+         int npasses = set_write_interlace_handling(pp, interlace_type);
+         int pass;
+
+         if (npasses != npasses_from_interlace_type(pp, interlace_type))
+            png_error(pp, "write: png_set_interlace_handling failed");
+
+         for (pass=0; pass<npasses; ++pass)
+         {
+            png_uint_32 y;
+
+            /* do_own_interlace is a pre-defined boolean (a #define) which is
+             * set if we have to work out the interlaced rows here.
+             */
+            for (y=0; y<h; ++y)
+            {
+               png_byte buffer[TRANSFORM_ROWMAX];
+
+               transform_row(pp, buffer, colour_type, bit_depth, y);
+
+#              if do_own_interlace
+                  /* If do_own_interlace *and* the image is interlaced we need a
+                   * reduced interlace row; this may be reduced to empty.
+                   */
+                  if (interlace_type == PNG_INTERLACE_ADAM7)
+                  {
+                     /* The row must not be written if it doesn't exist, notice
+                      * that there are two conditions here, either the row isn't
+                      * ever in the pass or the row would be but isn't wide
+                      * enough to contribute any pixels.  In fact the wPass test
+                      * can be used to skip the whole y loop in this case.
+                      */
+                     if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
+                         PNG_PASS_COLS(w, pass) > 0)
+                        interlace_row(buffer, buffer,
+                              bit_size(pp, colour_type, bit_depth), w, pass,
+                              0/*data always bigendian*/);
+                     else
+                        continue;
+                  }
+#              endif /* do_own_interlace */
+
+               choose_random_filter(pp, pass == 0 && y == 0);
+               png_write_row(pp, buffer);
+            }
+         }
+      }
+
+#ifdef PNG_TEXT_SUPPORTED
+      {
+         static char key[] = "end marker";
+         static char comment[] = "end";
+         png_text text;
+
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = TEXT_COMPRESSION;
+         text.key = key;
+         text.text = comment;
+         text.text_length = (sizeof comment)-1;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+
+      png_write_end(pp, pi);
+
+      /* And store this under the appropriate id, then clean up. */
+      store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
+         interlace_type, 0, 0, 0));
+
+      store_write_reset(ps);
+   }
+
+   Catch(fault)
+   {
+      /* Use the png_store returned by the exception. This may help the compiler
+       * because 'ps' is not used in this branch of the setjmp.  Note that fault
+       * and ps will always be the same value.
+       */
+      store_write_reset(fault);
+   }
+}
+
+static void
+make_transform_images(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   /* This is in case of errors. */
+   safecat(pm->this.test, sizeof pm->this.test, 0, "make standard images");
+
+   /* Use next_format to enumerate all the combinations we test, including
+    * generating multiple low bit depth palette images. Non-A images (palette
+    * and direct) are created with and without tRNS chunks.
+    */
+   while (next_format(&colour_type, &bit_depth, &palette_number, 1, 1))
+   {
+      int interlace_type;
+
+      for (interlace_type = PNG_INTERLACE_NONE;
+           interlace_type < INTERLACE_LAST; ++interlace_type)
+      {
+         char name[FILE_NAME_SIZE];
+
+         standard_name(name, sizeof name, 0, colour_type, bit_depth,
+            palette_number, interlace_type, 0, 0, do_own_interlace);
+         make_transform_image(&pm->this, colour_type, bit_depth, palette_number,
+            interlace_type, name);
+      }
+   }
+}
+
+/* Build a single row for the 'size' test images; this fills in only the
+ * first bit_width bits of the sample row.
+ */
+static void
+size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
+{
+   /* height is in the range 1 to 16, so: */
+   y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
+   /* the following ensures bits are set in small images: */
+   y ^= 0xA5;
+
+   while (bit_width >= 8)
+      *buffer++ = (png_byte)y++, bit_width -= 8;
+
+   /* There may be up to 7 remaining bits, these go in the most significant
+    * bits of the byte.
+    */
+   if (bit_width > 0)
+   {
+      png_uint_32 mask = (1U<<(8-bit_width))-1;
+      *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
+   }
+}
+
+static void
+make_size_image(png_store* const ps, png_byte const colour_type,
+    png_byte const bit_depth, int const interlace_type,
+    png_uint_32 const w, png_uint_32 const h,
+    int const do_interlace)
+{
+   context(ps, fault);
+
+   check_interlace_type(interlace_type);
+
+   Try
+   {
+      png_infop pi;
+      png_structp pp;
+      unsigned int pixel_size;
+
+      /* Make a name and get an appropriate id for the store: */
+      char name[FILE_NAME_SIZE];
+      png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
+         interlace_type, w, h, do_interlace);
+
+      standard_name_from_id(name, sizeof name, 0, id);
+      pp = set_store_for_write(ps, &pi, name);
+
+      /* In the event of a problem return control to the Catch statement below
+       * to do the clean up - it is not possible to 'return' directly from a Try
+       * block.
+       */
+      if (pp == NULL)
+         Throw ps;
+
+      png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
+         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+#ifdef PNG_TEXT_SUPPORTED
+      {
+         static char key[] = "image name"; /* must be writeable */
+         size_t pos;
+         png_text text;
+         char copy[FILE_NAME_SIZE];
+
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = TEXT_COMPRESSION;
+         text.key = key;
+         /* Yuck: the text must be writable! */
+         pos = safecat(copy, sizeof copy, 0, ps->wname);
+         text.text = copy;
+         text.text_length = pos;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+
+      if (colour_type == 3) /* palette */
+         init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
+
+      png_write_info(pp, pi);
+
+      /* Calculate the bit size, divide by 8 to get the byte size - this won't
+       * overflow because we know the w values are all small enough even for
+       * a system where 'unsigned int' is only 16 bits.
+       */
+      pixel_size = bit_size(pp, colour_type, bit_depth);
+      if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
+         png_error(pp, "size row size incorrect");
+
+      else
+      {
+         int npasses = npasses_from_interlace_type(pp, interlace_type);
+         png_uint_32 y;
+         int pass;
+         png_byte image[16][SIZE_ROWMAX];
+
+         /* To help consistent error detection make the parts of this buffer
+          * that aren't set below all '1':
+          */
+         memset(image, 0xff, sizeof image);
+
+         if (!do_interlace &&
+             npasses != set_write_interlace_handling(pp, interlace_type))
+            png_error(pp, "write: png_set_interlace_handling failed");
+
+         /* Prepare the whole image first to avoid making it 7 times: */
+         for (y=0; y<h; ++y)
+            size_row(image[y], w * pixel_size, y);
+
+         for (pass=0; pass<npasses; ++pass)
+         {
+            /* The following two are for checking the macros: */
+            png_uint_32 wPass = PNG_PASS_COLS(w, pass);
+
+            /* If do_interlace is set we don't call png_write_row for every
+             * row because some of them are empty.  In fact, for a 1x1 image,
+             * most of them are empty!
+             */
+            for (y=0; y<h; ++y)
+            {
+               png_const_bytep row = image[y];
+               png_byte tempRow[SIZE_ROWMAX];
+
+               /* If do_interlace *and* the image is interlaced we
+                * need a reduced interlace row; this may be reduced
+                * to empty.
+                */
+               if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
+               {
+                  /* The row must not be written if it doesn't exist, notice
+                   * that there are two conditions here, either the row isn't
+                   * ever in the pass or the row would be but isn't wide
+                   * enough to contribute any pixels.  In fact the wPass test
+                   * can be used to skip the whole y loop in this case.
+                   */
+                  if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
+                  {
+                     /* Set to all 1's for error detection (libpng tends to
+                      * set unset things to 0).
+                      */
+                     memset(tempRow, 0xff, sizeof tempRow);
+                     interlace_row(tempRow, row, pixel_size, w, pass,
+                           0/*data always bigendian*/);
+                     row = tempRow;
+                  }
+                  else
+                     continue;
+               }
+
+#           ifdef PNG_WRITE_FILTER_SUPPORTED
+               /* Only get to here if the row has some pixels in it, set the
+                * filters to 'all' for the very first row and thereafter to a
+                * single filter.  It isn't well documented, but png_set_filter
+                * does accept a filter number (per the spec) as well as a bit
+                * mask.
+                *
+                * The code now uses filters at random, except that on the first
+                * row of an image it ensures that a previous row filter is in
+                * the set so that libpng allocates the row buffer.
+                */
+               {
+                  int filters = 8 << random_mod(PNG_FILTER_VALUE_LAST);
+
+                  if (pass == 0 && y == 0 &&
+                      (filters < PNG_FILTER_UP || w == 1U))
+                     filters |= PNG_FILTER_UP;
+
+                  png_set_filter(pp, 0/*method*/, filters);
+               }
+#           endif
+
+               png_write_row(pp, row);
+            }
+         }
+      }
+
+#ifdef PNG_TEXT_SUPPORTED
+      {
+         static char key[] = "end marker";
+         static char comment[] = "end";
+         png_text text;
+
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = TEXT_COMPRESSION;
+         text.key = key;
+         text.text = comment;
+         text.text_length = (sizeof comment)-1;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+
+      png_write_end(pp, pi);
+
+      /* And store this under the appropriate id, then clean up. */
+      store_storefile(ps, id);
+
+      store_write_reset(ps);
+   }
+
+   Catch(fault)
+   {
+      /* Use the png_store returned by the exception. This may help the compiler
+       * because 'ps' is not used in this branch of the setjmp.  Note that fault
+       * and ps will always be the same value.
+       */
+      store_write_reset(fault);
+   }
+}
+
+static void
+make_size(png_store* const ps, png_byte const colour_type, int bdlo,
+    int const bdhi)
+{
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      png_uint_32 width;
+
+      for (width = 1; width <= 16; ++width)
+      {
+         png_uint_32 height;
+
+         for (height = 1; height <= 16; ++height)
+         {
+            /* The four combinations of DIY interlace and interlace or not -
+             * no interlace + DIY should be identical to no interlace with
+             * libpng doing it.
+             */
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
+               width, height, 0);
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
+               width, height, 1);
+#        ifdef PNG_WRITE_INTERLACING_SUPPORTED
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
+               width, height, 0);
+#        endif
+#        if CAN_WRITE_INTERLACE
+            /* 1.7.0 removes the hack that prevented app write of an interlaced
+             * image if WRITE_INTERLACE was not supported
+             */
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
+               width, height, 1);
+#        endif
+         }
+      }
+   }
+}
+
+static void
+make_size_images(png_store *ps)
+{
+   /* This is in case of errors. */
+   safecat(ps->test, sizeof ps->test, 0, "make size images");
+
+   /* Arguments are colour_type, low bit depth, high bit depth
+    */
+   make_size(ps, 0, 0, WRITE_BDHI);
+   make_size(ps, 2, 3, WRITE_BDHI);
+   make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
+   make_size(ps, 4, 3, WRITE_BDHI);
+   make_size(ps, 6, 3, WRITE_BDHI);
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* Return a row based on image id and 'y' for checking: */
+static void
+standard_row(png_const_structp pp, png_byte std[STANDARD_ROWMAX],
+   png_uint_32 id, png_uint_32 y)
+{
+   if (WIDTH_FROM_ID(id) == 0)
+      transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
+   else
+      size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
+         DEPTH_FROM_ID(id)), y);
+}
+#endif /* PNG_READ_SUPPORTED */
+
+/* Tests - individual test cases */
+/* Like 'make_standard' but errors are deliberately introduced into the calls
+ * to ensure that they get detected - it should not be possible to write an
+ * invalid image with libpng!
+ */
+/* TODO: the 'set' functions can probably all be made to take a
+ * png_const_structp rather than a modifiable one.
+ */
+#ifdef PNG_WARNINGS_SUPPORTED
+static void
+sBIT0_error_fn(png_structp pp, png_infop pi)
+{
+   /* 0 is invalid... */
+   png_color_8 bad;
+   bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
+   png_set_sBIT(pp, pi, &bad);
+}
+
+static void
+sBIT_error_fn(png_structp pp, png_infop pi)
+{
+   png_byte bit_depth;
+   png_color_8 bad;
+
+   if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
+      bit_depth = 8;
+
+   else
+      bit_depth = png_get_bit_depth(pp, pi);
+
+   /* Now we know the bit depth we can easily generate an invalid sBIT entry */
+   bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
+      (png_byte)(bit_depth+1);
+   png_set_sBIT(pp, pi, &bad);
+}
+
+static const struct
+{
+   void          (*fn)(png_structp, png_infop);
+   const char *msg;
+   unsigned int    warning :1; /* the error is a warning... */
+} error_test[] =
+    {
+       /* no warnings makes these errors undetectable prior to 1.7.0 */
+       { sBIT0_error_fn, "sBIT(0): failed to detect error",
+         PNG_LIBPNG_VER < 10700 },
+
+       { sBIT_error_fn, "sBIT(too big): failed to detect error",
+         PNG_LIBPNG_VER < 10700 },
+    };
+
+static void
+make_error(png_store* const ps, png_byte const colour_type,
+    png_byte bit_depth, int interlace_type, int test, png_const_charp name)
+{
+   context(ps, fault);
+
+   check_interlace_type(interlace_type);
+
+   Try
+   {
+      png_infop pi;
+      png_structp pp = set_store_for_write(ps, &pi, name);
+      png_uint_32 w, h;
+      gnu_volatile(pp)
+
+      if (pp == NULL)
+         Throw ps;
+
+      w = transform_width(pp, colour_type, bit_depth);
+      gnu_volatile(w)
+      h = transform_height(pp, colour_type, bit_depth);
+      gnu_volatile(h)
+      png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
+            PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+      if (colour_type == 3) /* palette */
+         init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
+
+      /* Time for a few errors; these are in various optional chunks, the
+       * standard tests test the standard chunks pretty well.
+       */
+#     define exception__prev exception_prev_1
+#     define exception__env exception_env_1
+      Try
+      {
+         gnu_volatile(exception__prev)
+
+         /* Expect this to throw: */
+         ps->expect_error = !error_test[test].warning;
+         ps->expect_warning = error_test[test].warning;
+         ps->saw_warning = 0;
+         error_test[test].fn(pp, pi);
+
+         /* Normally the error is only detected here: */
+         png_write_info(pp, pi);
+
+         /* And handle the case where it was only a warning: */
+         if (ps->expect_warning && ps->saw_warning)
+            Throw ps;
+
+         /* If we get here there is a problem, we have success - no error or
+          * no warning - when we shouldn't have success.  Log an error.
+          */
+         store_log(ps, pp, error_test[test].msg, 1 /*error*/);
+      }
+
+      Catch (fault)
+      { /* expected exit */
+      }
+#undef exception__prev
+#undef exception__env
+
+      /* And clear these flags */
+      ps->expect_warning = 0;
+
+      if (ps->expect_error)
+         ps->expect_error = 0;
+
+      else
+      {
+         /* Now write the whole image, just to make sure that the detected, or
+          * undetected, error has not created problems inside libpng.  This
+          * doesn't work if there was a png_error in png_write_info because that
+          * can abort before PLTE was written.
+          */
+         if (png_get_rowbytes(pp, pi) !=
+             transform_rowsize(pp, colour_type, bit_depth))
+            png_error(pp, "row size incorrect");
+
+         else
+         {
+            int npasses = set_write_interlace_handling(pp, interlace_type);
+            int pass;
+
+            if (npasses != npasses_from_interlace_type(pp, interlace_type))
+               png_error(pp, "write: png_set_interlace_handling failed");
+
+            for (pass=0; pass<npasses; ++pass)
+            {
+               png_uint_32 y;
+
+               for (y=0; y<h; ++y)
+               {
+                  png_byte buffer[TRANSFORM_ROWMAX];
+
+                  transform_row(pp, buffer, colour_type, bit_depth, y);
+
+#                 if do_own_interlace
+                     /* If do_own_interlace *and* the image is interlaced we
+                      * need a reduced interlace row; this may be reduced to
+                      * empty.
+                      */
+                     if (interlace_type == PNG_INTERLACE_ADAM7)
+                     {
+                        /* The row must not be written if it doesn't exist,
+                         * notice that there are two conditions here, either the
+                         * row isn't ever in the pass or the row would be but
+                         * isn't wide enough to contribute any pixels.  In fact
+                         * the wPass test can be used to skip the whole y loop
+                         * in this case.
+                         */
+                        if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
+                            PNG_PASS_COLS(w, pass) > 0)
+                           interlace_row(buffer, buffer,
+                                 bit_size(pp, colour_type, bit_depth), w, pass,
+                                 0/*data always bigendian*/);
+                        else
+                           continue;
+                     }
+#                 endif /* do_own_interlace */
+
+                  png_write_row(pp, buffer);
+               }
+            }
+         } /* image writing */
+
+         png_write_end(pp, pi);
+      }
+
+      /* The following deletes the file that was just written. */
+      store_write_reset(ps);
+   }
+
+   Catch(fault)
+   {
+      store_write_reset(fault);
+   }
+}
+
+static int
+make_errors(png_modifier* const pm, png_byte const colour_type,
+    int bdlo, int const bdhi)
+{
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      int interlace_type;
+
+      for (interlace_type = PNG_INTERLACE_NONE;
+           interlace_type < INTERLACE_LAST; ++interlace_type)
+      {
+         unsigned int test;
+         char name[FILE_NAME_SIZE];
+
+         standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
+            interlace_type, 0, 0, do_own_interlace);
+
+         for (test=0; test<ARRAY_SIZE(error_test); ++test)
+         {
+            make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
+               test, name);
+
+            if (fail(pm))
+               return 0;
+         }
+      }
+   }
+
+   return 1; /* keep going */
+}
+#endif /* PNG_WARNINGS_SUPPORTED */
+
+static void
+perform_error_test(png_modifier *pm)
+{
+#ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
+   /* Need to do this here because we just write in this test. */
+   safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
+
+   if (!make_errors(pm, 0, 0, WRITE_BDHI))
+      return;
+
+   if (!make_errors(pm, 2, 3, WRITE_BDHI))
+      return;
+
+   if (!make_errors(pm, 3, 0, 3))
+      return;
+
+   if (!make_errors(pm, 4, 3, WRITE_BDHI))
+      return;
+
+   if (!make_errors(pm, 6, 3, WRITE_BDHI))
+      return;
+#else
+   UNUSED(pm)
+#endif
+}
+
+/* This is just to validate the internal PNG formatting code - if this fails
+ * then the warning messages the library outputs will probably be garbage.
+ */
+static void
+perform_formatting_test(png_store *ps)
+{
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+   /* The handle into the formatting code is the RFC1123 support; this test does
+    * nothing if that is compiled out.
+    */
+   context(ps, fault);
+
+   Try
+   {
+      png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
+      png_const_charp result;
+#     if PNG_LIBPNG_VER >= 10600
+         char timestring[29];
+#     endif
+      png_structp pp;
+      png_time pt;
+
+      pp = set_store_for_write(ps, NULL, "libpng formatting test");
+
+      if (pp == NULL)
+         Throw ps;
+
+
+      /* Arbitrary settings: */
+      pt.year = 2079;
+      pt.month = 8;
+      pt.day = 29;
+      pt.hour = 13;
+      pt.minute = 53;
+      pt.second = 60; /* a leap second */
+
+#     if PNG_LIBPNG_VER < 10600
+         result = png_convert_to_rfc1123(pp, &pt);
+#     else
+         if (png_convert_to_rfc1123_buffer(timestring, &pt))
+            result = timestring;
+
+         else
+            result = NULL;
+#     endif
+
+      if (result == NULL)
+         png_error(pp, "png_convert_to_rfc1123 failed");
+
+      if (strcmp(result, correct) != 0)
+      {
+         size_t pos = 0;
+         char msg[128];
+
+         pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
+         pos = safecat(msg, sizeof msg, pos, correct);
+         pos = safecat(msg, sizeof msg, pos, ") returned: '");
+         pos = safecat(msg, sizeof msg, pos, result);
+         pos = safecat(msg, sizeof msg, pos, "'");
+
+         png_error(pp, msg);
+      }
+
+      store_write_reset(ps);
+   }
+
+   Catch(fault)
+   {
+      store_write_reset(fault);
+   }
+#else
+   UNUSED(ps)
+#endif
+}
+
+#ifdef PNG_READ_SUPPORTED
+/* Because we want to use the same code in both the progressive reader and the
+ * sequential reader it is necessary to deal with the fact that the progressive
+ * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
+ * must contain all the test parameters and all the local variables directly
+ * accessible to the sequential reader implementation.
+ *
+ * The technique adopted is to reinvent part of what Dijkstra termed a
+ * 'display'; an array of pointers to the stack frames of enclosing functions so
+ * that a nested function definition can access the local (C auto) variables of
+ * the functions that contain its definition.  In fact C provides the first
+ * pointer (the local variables - the stack frame pointer) and the last (the
+ * global variables - the BCPL global vector typically implemented as global
+ * addresses), this code requires one more pointer to make the display - the
+ * local variables (and function call parameters) of the function that actually
+ * invokes either the progressive or sequential reader.
+ *
+ * Perhaps confusingly this technique is confounded with classes - the
+ * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
+ * A gamma_display is a standard_display, taking advantage of the ANSI-C
+ * requirement that the pointer to the first member of a structure must be the
+ * same as the pointer to the structure.  This allows us to reuse standard_
+ * functions in the gamma test code; something that could not be done with
+ * nested functions!
+ */
+typedef struct standard_display
+{
+   png_store*  ps;             /* Test parameters (passed to the function) */
+   png_byte    colour_type;
+   png_byte    bit_depth;
+   png_byte    red_sBIT;       /* Input data sBIT values. */
+   png_byte    green_sBIT;
+   png_byte    blue_sBIT;
+   png_byte    alpha_sBIT;
+   png_byte    interlace_type;
+   png_byte    filler;         /* Output has a filler */
+   png_uint_32 id;             /* Calculated file ID */
+   png_uint_32 w;              /* Width of image */
+   png_uint_32 h;              /* Height of image */
+   int         npasses;        /* Number of interlaced passes */
+   png_uint_32 pixel_size;     /* Width of one pixel in bits */
+   png_uint_32 bit_width;      /* Width of output row in bits */
+   size_t      cbRow;          /* Bytes in a row of the output image */
+   int         do_interlace;   /* Do interlacing internally */
+   int         littleendian;   /* App (row) data is little endian */
+   int         is_transparent; /* Transparency information was present. */
+   int         has_tRNS;       /* color type GRAY or RGB with a tRNS chunk. */
+   int         speed;          /* Doing a speed test */
+   int         use_update_info;/* Call update_info, not start_image */
+   struct
+   {
+      png_uint_16 red;
+      png_uint_16 green;
+      png_uint_16 blue;
+   }           transparent;    /* The transparent color, if set. */
+   int         npalette;       /* Number of entries in the palette. */
+   store_palette
+               palette;
+} standard_display;
+
+static void
+standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
+   int do_interlace, int use_update_info)
+{
+   memset(dp, 0, sizeof *dp);
+
+   dp->ps = ps;
+   dp->colour_type = COL_FROM_ID(id);
+   dp->bit_depth = DEPTH_FROM_ID(id);
+   if (dp->bit_depth < 1 || dp->bit_depth > 16)
+      internal_error(ps, "internal: bad bit depth");
+   if (dp->colour_type == 3)
+      dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
+   else
+      dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
+         dp->bit_depth;
+   dp->interlace_type = INTERLACE_FROM_ID(id);
+   check_interlace_type(dp->interlace_type);
+   dp->id = id;
+   /* All the rest are filled in after the read_info: */
+   dp->w = 0;
+   dp->h = 0;
+   dp->npasses = 0;
+   dp->pixel_size = 0;
+   dp->bit_width = 0;
+   dp->cbRow = 0;
+   dp->do_interlace = do_interlace;
+   dp->littleendian = 0;
+   dp->is_transparent = 0;
+   dp->speed = ps->speed;
+   dp->use_update_info = use_update_info;
+   dp->npalette = 0;
+   /* Preset the transparent color to black: */
+   memset(&dp->transparent, 0, sizeof dp->transparent);
+   /* Preset the palette to full intensity/opaque throughout: */
+   memset(dp->palette, 0xff, sizeof dp->palette);
+}
+
+/* Initialize the palette fields - this must be done later because the palette
+ * comes from the particular png_store_file that is selected.
+ */
+static void
+standard_palette_init(standard_display *dp)
+{
+   store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
+
+   /* The remaining entries remain white/opaque. */
+   if (dp->npalette > 0)
+   {
+      int i = dp->npalette;
+      memcpy(dp->palette, palette, i * sizeof *palette);
+
+      /* Check for a non-opaque palette entry: */
+      while (--i >= 0)
+         if (palette[i].alpha < 255)
+            break;
+
+#     ifdef __GNUC__
+         /* GCC can't handle the more obviously optimizable version. */
+         if (i >= 0)
+            dp->is_transparent = 1;
+         else
+            dp->is_transparent = 0;
+#     else
+         dp->is_transparent = (i >= 0);
+#     endif
+   }
+}
+
+/* Utility to read the palette from the PNG file and convert it into
+ * store_palette format.  This returns 1 if there is any transparency in the
+ * palette (it does not check for a transparent colour in the non-palette case.)
+ */
+static int
+read_palette(store_palette palette, int *npalette, png_const_structp pp,
+   png_infop pi)
+{
+   png_colorp pal;
+   png_bytep trans_alpha;
+   int num;
+
+   pal = 0;
+   *npalette = -1;
+
+   if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
+   {
+      int i = *npalette;
+
+      if (i <= 0 || i > 256)
+         png_error(pp, "validate: invalid PLTE count");
+
+      while (--i >= 0)
+      {
+         palette[i].red = pal[i].red;
+         palette[i].green = pal[i].green;
+         palette[i].blue = pal[i].blue;
+      }
+
+      /* Mark the remainder of the entries with a flag value (other than
+       * white/opaque which is the flag value stored above.)
+       */
+      memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
+   }
+
+   else /* !png_get_PLTE */
+   {
+      if (*npalette != (-1))
+         png_error(pp, "validate: invalid PLTE result");
+      /* But there is no palette, so record this: */
+      *npalette = 0;
+      memset(palette, 113, sizeof (store_palette));
+   }
+
+   trans_alpha = 0;
+   num = 2; /* force error below */
+   if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
+      (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
+      /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
+       * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
+       * so in the above call we get a success, we get a pointer (who knows what
+       * to) and we get num_trans == 0:
+       */
+      !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
+   {
+      int i;
+
+      /* Any of these are crash-worthy - given the implementation of
+       * png_get_tRNS up to 1.5 an app won't crash if it just checks the
+       * result above and fails to check that the variables it passed have
+       * actually been filled in!  Note that if the app were to pass the
+       * last, png_color_16p, variable too it couldn't rely on this.
+       */
+      if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
+         png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
+
+      for (i=0; i<num; ++i)
+         palette[i].alpha = trans_alpha[i];
+
+      for (num=*npalette; i<num; ++i)
+         palette[i].alpha = 255;
+
+      for (; i<256; ++i)
+         palette[i].alpha = 33; /* flag value */
+
+      return 1; /* transparency */
+   }
+
+   else
+   {
+      /* No palette transparency - just set the alpha channel to opaque. */
+      int i;
+
+      for (i=0, num=*npalette; i<num; ++i)
+         palette[i].alpha = 255;
+
+      for (; i<256; ++i)
+         palette[i].alpha = 55; /* flag value */
+
+      return 0; /* no transparency */
+   }
+}
+
+/* Utility to validate the palette if it should not have changed (the
+ * non-transform case).
+ */
+static void
+standard_palette_validate(standard_display *dp, png_const_structp pp,
+   png_infop pi)
+{
+   int npalette;
+   store_palette palette;
+
+   if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
+      png_error(pp, "validate: palette transparency changed");
+
+   if (npalette != dp->npalette)
+   {
+      size_t pos = 0;
+      char msg[64];
+
+      pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
+      pos = safecatn(msg, sizeof msg, pos, dp->npalette);
+      pos = safecat(msg, sizeof msg, pos, " -> ");
+      pos = safecatn(msg, sizeof msg, pos, npalette);
+      png_error(pp, msg);
+   }
+
+   {
+      int i = npalette; /* npalette is aliased */
+
+      while (--i >= 0)
+         if (palette[i].red != dp->palette[i].red ||
+            palette[i].green != dp->palette[i].green ||
+            palette[i].blue != dp->palette[i].blue ||
+            palette[i].alpha != dp->palette[i].alpha)
+            png_error(pp, "validate: PLTE or tRNS chunk changed");
+   }
+}
+
+/* By passing a 'standard_display' the progressive callbacks can be used
+ * directly by the sequential code, the functions suffixed "_imp" are the
+ * implementations, the functions without the suffix are the callbacks.
+ *
+ * The code for the info callback is split into two because this callback calls
+ * png_read_update_info or png_start_read_image and what gets called depends on
+ * whether the info needs updating (we want to test both calls in pngvalid.)
+ */
+static void
+standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
+{
+   if (png_get_bit_depth(pp, pi) != dp->bit_depth)
+      png_error(pp, "validate: bit depth changed");
+
+   if (png_get_color_type(pp, pi) != dp->colour_type)
+      png_error(pp, "validate: color type changed");
+
+   if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
+      png_error(pp, "validate: filter type changed");
+
+   if (png_get_interlace_type(pp, pi) != dp->interlace_type)
+      png_error(pp, "validate: interlacing changed");
+
+   if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
+      png_error(pp, "validate: compression type changed");
+
+   dp->w = png_get_image_width(pp, pi);
+
+   if (dp->w != standard_width(pp, dp->id))
+      png_error(pp, "validate: image width changed");
+
+   dp->h = png_get_image_height(pp, pi);
+
+   if (dp->h != standard_height(pp, dp->id))
+      png_error(pp, "validate: image height changed");
+
+   /* Record (but don't check at present) the input sBIT according to the colour
+    * type information.
+    */
+   {
+      png_color_8p sBIT = 0;
+
+      if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
+      {
+         int sBIT_invalid = 0;
+
+         if (sBIT == 0)
+            png_error(pp, "validate: unexpected png_get_sBIT result");
+
+         if (dp->colour_type & PNG_COLOR_MASK_COLOR)
+         {
+            if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->red_sBIT = sBIT->red;
+
+            if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->green_sBIT = sBIT->green;
+
+            if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->blue_sBIT = sBIT->blue;
+         }
+
+         else /* !COLOR */
+         {
+            if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
+         }
+
+         /* All 8 bits in tRNS for a palette image are significant - see the
+          * spec.
+          */
+         if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
+         {
+            if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->alpha_sBIT = sBIT->alpha;
+         }
+
+         if (sBIT_invalid)
+            png_error(pp, "validate: sBIT value out of range");
+      }
+   }
+
+   /* Important: this is validating the value *before* any transforms have been
+    * put in place.  It doesn't matter for the standard tests, where there are
+    * no transforms, but it does for other tests where rowbytes may change after
+    * png_read_update_info.
+    */
+   if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
+      png_error(pp, "validate: row size changed");
+
+   /* Validate the colour type 3 palette (this can be present on other color
+    * types.)
+    */
+   standard_palette_validate(dp, pp, pi);
+
+   /* In any case always check for a transparent color (notice that the
+    * colour type 3 case must not give a successful return on the get_tRNS call
+    * with these arguments!)
+    */
+   {
+      png_color_16p trans_color = 0;
+
+      if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
+      {
+         if (trans_color == 0)
+            png_error(pp, "validate: unexpected png_get_tRNS (color) result");
+
+         switch (dp->colour_type)
+         {
+         case 0:
+            dp->transparent.red = dp->transparent.green = dp->transparent.blue =
+               trans_color->gray;
+            dp->has_tRNS = 1;
+            break;
+
+         case 2:
+            dp->transparent.red = trans_color->red;
+            dp->transparent.green = trans_color->green;
+            dp->transparent.blue = trans_color->blue;
+            dp->has_tRNS = 1;
+            break;
+
+         case 3:
+            /* Not expected because it should result in the array case
+             * above.
+             */
+            png_error(pp, "validate: unexpected png_get_tRNS result");
+            break;
+
+         default:
+            png_error(pp, "validate: invalid tRNS chunk with alpha image");
+         }
+      }
+   }
+
+   /* Read the number of passes - expected to match the value used when
+    * creating the image (interlaced or not).  This has the side effect of
+    * turning on interlace handling (if do_interlace is not set.)
+    */
+   dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
+   if (!dp->do_interlace)
+   {
+#     ifdef PNG_READ_INTERLACING_SUPPORTED
+         if (dp->npasses != png_set_interlace_handling(pp))
+            png_error(pp, "validate: file changed interlace type");
+#     else /* !READ_INTERLACING */
+         /* This should never happen: the relevant tests (!do_interlace) should
+          * not be run.
+          */
+         if (dp->npasses > 1)
+            png_error(pp, "validate: no libpng interlace support");
+#     endif /* !READ_INTERLACING */
+   }
+
+   /* Caller calls png_read_update_info or png_start_read_image now, then calls
+    * part2.
+    */
+}
+
+/* This must be called *after* the png_read_update_info call to get the correct
+ * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
+ * image.
+ */
+static void
+standard_info_part2(standard_display *dp, png_const_structp pp,
+    png_const_infop pi, int nImages)
+{
+   /* Record cbRow now that it can be found. */
+   {
+      png_byte ct = png_get_color_type(pp, pi);
+      png_byte bd = png_get_bit_depth(pp, pi);
+
+      if (bd >= 8 && (ct == PNG_COLOR_TYPE_RGB || ct == PNG_COLOR_TYPE_GRAY) &&
+          dp->filler)
+          ct |= 4; /* handle filler as faked alpha channel */
+
+      dp->pixel_size = bit_size(pp, ct, bd);
+   }
+   dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
+   dp->cbRow = png_get_rowbytes(pp, pi);
+
+   /* Validate the rowbytes here again. */
+   if (dp->cbRow != (dp->bit_width+7)/8)
+      png_error(pp, "bad png_get_rowbytes calculation");
+
+   /* Then ensure there is enough space for the output image(s). */
+   store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
+}
+
+static void
+standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
+    int nImages)
+{
+   /* Note that the validation routine has the side effect of turning on
+    * interlace handling in the subsequent code.
+    */
+   standard_info_part1(dp, pp, pi);
+
+   /* And the info callback has to call this (or png_read_update_info - see
+    * below in the png_modifier code for that variant.
+    */
+   if (dp->use_update_info)
+   {
+      /* For debugging the effect of multiple calls: */
+      int i = dp->use_update_info;
+      while (i-- > 0)
+         png_read_update_info(pp, pi);
+   }
+
+   else
+      png_start_read_image(pp);
+
+   /* Validate the height, width and rowbytes plus ensure that sufficient buffer
+    * exists for decoding the image.
+    */
+   standard_info_part2(dp, pp, pi, nImages);
+}
+
+static void PNGCBAPI
+standard_info(png_structp pp, png_infop pi)
+{
+   standard_display *dp = voidcast(standard_display*,
+      png_get_progressive_ptr(pp));
+
+   /* Call with nImages==1 because the progressive reader can only produce one
+    * image.
+    */
+   standard_info_imp(dp, pp, pi, 1 /*only one image*/);
+}
+
+static void PNGCBAPI
+progressive_row(png_structp ppIn, png_bytep new_row, png_uint_32 y, int pass)
+{
+   png_const_structp pp = ppIn;
+   const standard_display *dp = voidcast(standard_display*,
+      png_get_progressive_ptr(pp));
+
+   /* When handling interlacing some rows will be absent in each pass, the
+    * callback still gets called, but with a NULL pointer.  This is checked
+    * in the 'else' clause below.  We need our own 'cbRow', but we can't call
+    * png_get_rowbytes because we got no info structure.
+    */
+   if (new_row != NULL)
+   {
+      png_bytep row;
+
+      /* In the case where the reader doesn't do the interlace it gives
+       * us the y in the sub-image:
+       */
+      if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
+      {
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+         /* Use this opportunity to validate the png 'current' APIs: */
+         if (y != png_get_current_row_number(pp))
+            png_error(pp, "png_get_current_row_number is broken");
+
+         if (pass != png_get_current_pass_number(pp))
+            png_error(pp, "png_get_current_pass_number is broken");
+#endif /* USER_TRANSFORM_INFO */
+
+         y = PNG_ROW_FROM_PASS_ROW(y, pass);
+      }
+
+      /* Validate this just in case. */
+      if (y >= dp->h)
+         png_error(pp, "invalid y to progressive row callback");
+
+      row = store_image_row(dp->ps, pp, 0, y);
+
+      /* Combine the new row into the old: */
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+      if (dp->do_interlace)
+#endif /* READ_INTERLACING */
+      {
+         if (dp->interlace_type == PNG_INTERLACE_ADAM7)
+            deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass,
+                  dp->littleendian);
+         else
+            row_copy(row, new_row, dp->pixel_size * dp->w, dp->littleendian);
+      }
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+      else
+         png_progressive_combine_row(pp, row, new_row);
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+   }
+
+   else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
+       PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
+       PNG_PASS_COLS(dp->w, pass) > 0)
+      png_error(pp, "missing row in progressive de-interlacing");
+}
+
+static void
+sequential_row(standard_display *dp, png_structp pp, png_infop pi,
+    int iImage, int iDisplay)
+{
+   int npasses = dp->npasses;
+   int do_interlace = dp->do_interlace &&
+      dp->interlace_type == PNG_INTERLACE_ADAM7;
+   png_uint_32 height = standard_height(pp, dp->id);
+   png_uint_32 width = standard_width(pp, dp->id);
+   const png_store* ps = dp->ps;
+   int pass;
+
+   for (pass=0; pass<npasses; ++pass)
+   {
+      png_uint_32 y;
+      png_uint_32 wPass = PNG_PASS_COLS(width, pass);
+
+      for (y=0; y<height; ++y)
+      {
+         if (do_interlace)
+         {
+            /* wPass may be zero or this row may not be in this pass.
+             * png_read_row must not be called in either case.
+             */
+            if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
+            {
+               /* Read the row into a pair of temporary buffers, then do the
+                * merge here into the output rows.
+                */
+               png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
+
+               /* The following aids (to some extent) error detection - we can
+                * see where png_read_row wrote.  Use opposite values in row and
+                * display to make this easier.  Don't use 0xff (which is used in
+                * the image write code to fill unused bits) or 0 (which is a
+                * likely value to overwrite unused bits with).
+                */
+               memset(row, 0xc5, sizeof row);
+               memset(display, 0x5c, sizeof display);
+
+               png_read_row(pp, row, display);
+
+               if (iImage >= 0)
+                  deinterlace_row(store_image_row(ps, pp, iImage, y), row,
+                     dp->pixel_size, dp->w, pass, dp->littleendian);
+
+               if (iDisplay >= 0)
+                  deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
+                     dp->pixel_size, dp->w, pass, dp->littleendian);
+            }
+         }
+         else
+            png_read_row(pp,
+               iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
+               iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
+      }
+   }
+
+   /* And finish the read operation (only really necessary if the caller wants
+    * to find additional data in png_info from chunks after the last IDAT.)
+    */
+   png_read_end(pp, pi);
+}
+
+#ifdef PNG_TEXT_SUPPORTED
+static void
+standard_check_text(png_const_structp pp, png_const_textp tp,
+   png_const_charp keyword, png_const_charp text)
+{
+   char msg[1024];
+   size_t pos = safecat(msg, sizeof msg, 0, "text: ");
+   size_t ok;
+
+   pos = safecat(msg, sizeof msg, pos, keyword);
+   pos = safecat(msg, sizeof msg, pos, ": ");
+   ok = pos;
+
+   if (tp->compression != TEXT_COMPRESSION)
+   {
+      char buf[64];
+
+      sprintf(buf, "compression [%d->%d], ", TEXT_COMPRESSION,
+         tp->compression);
+      pos = safecat(msg, sizeof msg, pos, buf);
+   }
+
+   if (tp->key == NULL || strcmp(tp->key, keyword) != 0)
+   {
+      pos = safecat(msg, sizeof msg, pos, "keyword \"");
+      if (tp->key != NULL)
+      {
+         pos = safecat(msg, sizeof msg, pos, tp->key);
+         pos = safecat(msg, sizeof msg, pos, "\", ");
+      }
+
+      else
+         pos = safecat(msg, sizeof msg, pos, "null, ");
+   }
+
+   if (tp->text == NULL)
+      pos = safecat(msg, sizeof msg, pos, "text lost, ");
+
+   else
+   {
+      if (tp->text_length != strlen(text))
+      {
+         char buf[64];
+         sprintf(buf, "text length changed[%lu->%lu], ",
+            (unsigned long)strlen(text), (unsigned long)tp->text_length);
+         pos = safecat(msg, sizeof msg, pos, buf);
+      }
+
+      if (strcmp(tp->text, text) != 0)
+      {
+         pos = safecat(msg, sizeof msg, pos, "text becomes \"");
+         pos = safecat(msg, sizeof msg, pos, tp->text);
+         pos = safecat(msg, sizeof msg, pos, "\" (was \"");
+         pos = safecat(msg, sizeof msg, pos, text);
+         pos = safecat(msg, sizeof msg, pos, "\"), ");
+      }
+   }
+
+   if (tp->itxt_length != 0)
+      pos = safecat(msg, sizeof msg, pos, "iTXt length set, ");
+
+   if (tp->lang != NULL)
+   {
+      pos = safecat(msg, sizeof msg, pos, "iTXt language \"");
+      pos = safecat(msg, sizeof msg, pos, tp->lang);
+      pos = safecat(msg, sizeof msg, pos, "\", ");
+   }
+
+   if (tp->lang_key != NULL)
+   {
+      pos = safecat(msg, sizeof msg, pos, "iTXt keyword \"");
+      pos = safecat(msg, sizeof msg, pos, tp->lang_key);
+      pos = safecat(msg, sizeof msg, pos, "\", ");
+   }
+
+   if (pos > ok)
+   {
+      msg[pos-2] = '\0'; /* Remove the ", " at the end */
+      png_error(pp, msg);
+   }
+}
+
+static void
+standard_text_validate(standard_display *dp, png_const_structp pp,
+   png_infop pi, int check_end)
+{
+   png_textp tp = NULL;
+   png_uint_32 num_text = png_get_text(pp, pi, &tp, NULL);
+
+   if (num_text == 2 && tp != NULL)
+   {
+      standard_check_text(pp, tp, "image name", dp->ps->current->name);
+
+      /* This exists because prior to 1.5.18 the progressive reader left the
+       * png_struct z_stream unreset at the end of the image, so subsequent
+       * attempts to use it simply returns Z_STREAM_END.
+       */
+      if (check_end)
+         standard_check_text(pp, tp+1, "end marker", "end");
+   }
+
+   else
+   {
+      char msg[64];
+
+      sprintf(msg, "expected two text items, got %lu",
+         (unsigned long)num_text);
+      png_error(pp, msg);
+   }
+}
+#else
+#  define standard_text_validate(dp,pp,pi,check_end) ((void)0)
+#endif
+
+static void
+standard_row_validate(standard_display *dp, png_const_structp pp,
+   int iImage, int iDisplay, png_uint_32 y)
+{
+   int where;
+   png_byte std[STANDARD_ROWMAX];
+
+   /* The row must be pre-initialized to the magic number here for the size
+    * tests to pass:
+    */
+   memset(std, 178, sizeof std);
+   standard_row(pp, std, dp->id, y);
+
+   /* At the end both the 'row' and 'display' arrays should end up identical.
+    * In earlier passes 'row' will be partially filled in, with only the pixels
+    * that have been read so far, but 'display' will have those pixels
+    * replicated to fill the unread pixels while reading an interlaced image.
+    */
+   if (iImage >= 0 &&
+      (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
+            dp->bit_width)) != 0)
+   {
+      char msg[64];
+      sprintf(msg, "PNG image row[%lu][%d] changed from %.2x to %.2x",
+         (unsigned long)y, where-1, std[where-1],
+         store_image_row(dp->ps, pp, iImage, y)[where-1]);
+      png_error(pp, msg);
+   }
+
+   if (iDisplay >= 0 &&
+      (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
+         dp->bit_width)) != 0)
+   {
+      char msg[64];
+      sprintf(msg, "display row[%lu][%d] changed from %.2x to %.2x",
+         (unsigned long)y, where-1, std[where-1],
+         store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
+      png_error(pp, msg);
+   }
+}
+
+static void
+standard_image_validate(standard_display *dp, png_const_structp pp, int iImage,
+    int iDisplay)
+{
+   png_uint_32 y;
+
+   if (iImage >= 0)
+      store_image_check(dp->ps, pp, iImage);
+
+   if (iDisplay >= 0)
+      store_image_check(dp->ps, pp, iDisplay);
+
+   for (y=0; y<dp->h; ++y)
+      standard_row_validate(dp, pp, iImage, iDisplay, y);
+
+   /* This avoids false positives if the validation code is never called! */
+   dp->ps->validated = 1;
+}
+
+static void PNGCBAPI
+standard_end(png_structp ppIn, png_infop pi)
+{
+   png_const_structp pp = ppIn;
+   standard_display *dp = voidcast(standard_display*,
+      png_get_progressive_ptr(pp));
+
+   UNUSED(pi)
+
+   /* Validate the image - progressive reading only produces one variant for
+    * interlaced images.
+    */
+   standard_text_validate(dp, pp, pi,
+      PNG_LIBPNG_VER >= 10518/*check_end: see comments above*/);
+   standard_image_validate(dp, pp, 0, -1);
+}
+
+/* A single test run checking the standard image to ensure it is not damaged. */
+static void
+standard_test(png_store* const psIn, png_uint_32 const id,
+   int do_interlace, int use_update_info)
+{
+   standard_display d;
+   context(psIn, fault);
+
+   /* Set up the display (stack frame) variables from the arguments to the
+    * function and initialize the locals that are filled in later.
+    */
+   standard_display_init(&d, psIn, id, do_interlace, use_update_info);
+
+   /* Everything is protected by a Try/Catch.  The functions called also
+    * typically have local Try/Catch blocks.
+    */
+   Try
+   {
+      png_structp pp;
+      png_infop pi;
+
+      /* Get a png_struct for reading the image. This will throw an error if it
+       * fails, so we don't need to check the result.
+       */
+      pp = set_store_for_read(d.ps, &pi, d.id,
+         d.do_interlace ?  (d.ps->progressive ?
+            "pngvalid progressive deinterlacer" :
+            "pngvalid sequential deinterlacer") : (d.ps->progressive ?
+               "progressive reader" : "sequential reader"));
+
+      /* Initialize the palette correctly from the png_store_file. */
+      standard_palette_init(&d);
+
+      /* Introduce the correct read function. */
+      if (d.ps->progressive)
+      {
+         png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
+            standard_end);
+
+         /* Now feed data into the reader until we reach the end: */
+         store_progressive_read(d.ps, pp, pi);
+      }
+      else
+      {
+         /* Note that this takes the store, not the display. */
+         png_set_read_fn(pp, d.ps, store_read);
+
+         /* Check the header values: */
+         png_read_info(pp, pi);
+
+         /* The code tests both versions of the images that the sequential
+          * reader can produce.
+          */
+         standard_info_imp(&d, pp, pi, 2 /*images*/);
+
+         /* Need the total bytes in the image below; we can't get to this point
+          * unless the PNG file values have been checked against the expected
+          * values.
+          */
+         {
+            sequential_row(&d, pp, pi, 0, 1);
+
+            /* After the last pass loop over the rows again to check that the
+             * image is correct.
+             */
+            if (!d.speed)
+            {
+               standard_text_validate(&d, pp, pi, 1/*check_end*/);
+               standard_image_validate(&d, pp, 0, 1);
+            }
+            else
+               d.ps->validated = 1;
+         }
+      }
+
+      /* Check for validation. */
+      if (!d.ps->validated)
+         png_error(pp, "image read failed silently");
+
+      /* Successful completion. */
+   }
+
+   Catch(fault)
+      d.ps = fault; /* make sure this hasn't been clobbered. */
+
+   /* In either case clean up the store. */
+   store_read_reset(d.ps);
+}
+
+static int
+test_standard(png_modifier* const pm, png_byte const colour_type,
+    int bdlo, int const bdhi)
+{
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      int interlace_type;
+
+      for (interlace_type = PNG_INTERLACE_NONE;
+           interlace_type < INTERLACE_LAST; ++interlace_type)
+      {
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
+            0/*palette*/, interlace_type, 0, 0, 0), do_read_interlace,
+            pm->use_update_info);
+
+         if (fail(pm))
+            return 0;
+      }
+   }
+
+   return 1; /* keep going */
+}
+
+static void
+perform_standard_test(png_modifier *pm)
+{
+   /* Test each colour type over the valid range of bit depths (expressed as
+    * log2(bit_depth) in turn, stop as soon as any error is detected.
+    */
+   if (!test_standard(pm, 0, 0, READ_BDHI))
+      return;
+
+   if (!test_standard(pm, 2, 3, READ_BDHI))
+      return;
+
+   if (!test_standard(pm, 3, 0, 3))
+      return;
+
+   if (!test_standard(pm, 4, 3, READ_BDHI))
+      return;
+
+   if (!test_standard(pm, 6, 3, READ_BDHI))
+      return;
+}
+
+
+/********************************** SIZE TESTS ********************************/
+static int
+test_size(png_modifier* const pm, png_byte const colour_type,
+    int bdlo, int const bdhi)
+{
+   /* Run the tests on each combination.
+    *
+    * NOTE: on my 32 bit x86 each of the following blocks takes
+    * a total of 3.5 seconds if done across every combo of bit depth
+    * width and height.  This is a waste of time in practice, hence the
+    * hinc and winc stuff:
+    */
+   static const png_byte hinc[] = {1, 3, 11, 1, 5};
+   static const png_byte winc[] = {1, 9, 5, 7, 1};
+   int save_bdlo = bdlo;
+
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      png_uint_32 h, w;
+
+      for (h=1; h<=16; h+=hinc[bdlo])
+      {
+         for (w=1; w<=16; w+=winc[bdlo])
+         {
+            /* First test all the 'size' images against the sequential
+            * reader using libpng to deinterlace (where required.)  This
+            * validates the write side of libpng.  There are four possibilities
+            * to validate.
+            */
+            standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
+               0/*palette*/, PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
+               pm->use_update_info);
+
+            if (fail(pm))
+               return 0;
+
+            standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
+               0/*palette*/, PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
+               pm->use_update_info);
+
+            if (fail(pm))
+               return 0;
+
+            /* Now validate the interlaced read side - do_interlace true,
+            * in the progressive case this does actually make a difference
+            * to the code used in the non-interlaced case too.
+            */
+            standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
+               0/*palette*/, PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
+               pm->use_update_info);
+
+            if (fail(pm))
+               return 0;
+
+#        if CAN_WRITE_INTERLACE
+            /* Validate the pngvalid code itself: */
+            standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
+               0/*palette*/, PNG_INTERLACE_ADAM7, w, h, 1), 1/*do_interlace*/,
+               pm->use_update_info);
+
+            if (fail(pm))
+               return 0;
+#        endif
+         }
+      }
+   }
+
+   /* Now do the tests of libpng interlace handling, after we have made sure
+    * that the pngvalid version works:
+    */
+   for (bdlo = save_bdlo; bdlo <= bdhi; ++bdlo)
+   {
+      png_uint_32 h, w;
+
+      for (h=1; h<=16; h+=hinc[bdlo])
+      {
+         for (w=1; w<=16; w+=winc[bdlo])
+         {
+#        ifdef PNG_READ_INTERLACING_SUPPORTED
+            /* Test with pngvalid generated interlaced images first; we have
+            * already verify these are ok (unless pngvalid has self-consistent
+            * read/write errors, which is unlikely), so this detects errors in
+            * the read side first:
+            */
+#        if CAN_WRITE_INTERLACE
+            standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
+               0/*palette*/, PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
+               pm->use_update_info);
+
+            if (fail(pm))
+               return 0;
+#        endif
+#        endif /* READ_INTERLACING */
+
+#        ifdef PNG_WRITE_INTERLACING_SUPPORTED
+            /* Test the libpng write side against the pngvalid read side: */
+            standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
+               0/*palette*/, PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
+               pm->use_update_info);
+
+            if (fail(pm))
+               return 0;
+#        endif
+
+#        ifdef PNG_READ_INTERLACING_SUPPORTED
+#        ifdef PNG_WRITE_INTERLACING_SUPPORTED
+            /* Test both together: */
+            standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
+               0/*palette*/, PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
+               pm->use_update_info);
+
+            if (fail(pm))
+               return 0;
+#        endif
+#        endif /* READ_INTERLACING */
+         }
+      }
+   }
+
+   return 1; /* keep going */
+}
+
+static void
+perform_size_test(png_modifier *pm)
+{
+   /* Test each colour type over the valid range of bit depths (expressed as
+    * log2(bit_depth) in turn, stop as soon as any error is detected.
+    */
+   if (!test_size(pm, 0, 0, READ_BDHI))
+      return;
+
+   if (!test_size(pm, 2, 3, READ_BDHI))
+      return;
+
+   /* For the moment don't do the palette test - it's a waste of time when
+    * compared to the grayscale test.
+    */
+#if 0
+   if (!test_size(pm, 3, 0, 3))
+      return;
+#endif
+
+   if (!test_size(pm, 4, 3, READ_BDHI))
+      return;
+
+   if (!test_size(pm, 6, 3, READ_BDHI))
+      return;
+}
+
+
+/******************************* TRANSFORM TESTS ******************************/
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* A set of tests to validate libpng image transforms.  The possibilities here
+ * are legion because the transforms can be combined in a combinatorial
+ * fashion.  To deal with this some measure of restraint is required, otherwise
+ * the tests would take forever.
+ */
+typedef struct image_pixel
+{
+   /* A local (pngvalid) representation of a PNG pixel, in all its
+    * various forms.
+    */
+   unsigned int red, green, blue, alpha; /* For non-palette images. */
+   unsigned int palette_index;           /* For a palette image. */
+   png_byte     colour_type;             /* As in the spec. */
+   png_byte     bit_depth;               /* Defines bit size in row */
+   png_byte     sample_depth;            /* Scale of samples */
+   unsigned int have_tRNS :1;            /* tRNS chunk may need processing */
+   unsigned int swap_rgb :1;             /* RGB swapped to BGR */
+   unsigned int alpha_first :1;          /* Alpha at start, not end */
+   unsigned int alpha_inverted :1;       /* Alpha channel inverted */
+   unsigned int mono_inverted :1;        /* Gray channel inverted */
+   unsigned int swap16 :1;               /* Byte swap 16-bit components */
+   unsigned int littleendian :1;         /* High bits on right */
+   unsigned int sig_bits :1;             /* Pixel shifted (sig bits only) */
+
+   /* For checking the code calculates double precision floating point values
+    * along with an error value, accumulated from the transforms.  Because an
+    * sBIT setting allows larger error bounds (indeed, by the spec, apparently
+    * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
+    * channel is stored.  This sBIT value is folded in to the stored error value
+    * at the end of the application of the transforms to the pixel.
+    *
+    * If sig_bits is set above the red, green, blue and alpha values have been
+    * scaled so they only contain the significant bits of the component values.
+    */
+   double   redf, greenf, bluef, alphaf;
+   double   rede, greene, bluee, alphae;
+   png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
+} image_pixel;
+
+/* Shared utility function, see below. */
+static void
+image_pixel_setf(image_pixel *this, unsigned int rMax, unsigned int gMax,
+        unsigned int bMax, unsigned int aMax)
+{
+   this->redf = this->red / (double)rMax;
+   this->greenf = this->green / (double)gMax;
+   this->bluef = this->blue / (double)bMax;
+   this->alphaf = this->alpha / (double)aMax;
+
+   if (this->red < rMax)
+      this->rede = this->redf * DBL_EPSILON;
+   else
+      this->rede = 0;
+   if (this->green < gMax)
+      this->greene = this->greenf * DBL_EPSILON;
+   else
+      this->greene = 0;
+   if (this->blue < bMax)
+      this->bluee = this->bluef * DBL_EPSILON;
+   else
+      this->bluee = 0;
+   if (this->alpha < aMax)
+      this->alphae = this->alphaf * DBL_EPSILON;
+   else
+      this->alphae = 0;
+}
+
+/* Initialize the structure for the next pixel - call this before doing any
+ * transforms and call it for each pixel since all the fields may need to be
+ * reset.
+ */
+static void
+image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
+    png_byte bit_depth, png_uint_32 x, store_palette palette,
+    const image_pixel *format /*from pngvalid transform of input*/)
+{
+   png_byte sample_depth =
+      (png_byte)(colour_type == PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
+   unsigned int max = (1U<<sample_depth)-1;
+   int swap16 = (format != 0 && format->swap16);
+   int littleendian = (format != 0 && format->littleendian);
+   int sig_bits = (format != 0 && format->sig_bits);
+
+   /* Initially just set everything to the same number and the alpha to opaque.
+    * Note that this currently assumes a simple palette where entry x has colour
+    * rgb(x,x,x)!
+    */
+   this->palette_index = this->red = this->green = this->blue =
+      sample(row, colour_type, bit_depth, x, 0, swap16, littleendian);
+   this->alpha = max;
+   this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
+      sample_depth;
+
+   /* Then override as appropriate: */
+   if (colour_type == 3) /* palette */
+   {
+      /* This permits the caller to default to the sample value. */
+      if (palette != 0)
+      {
+         unsigned int i = this->palette_index;
+
+         this->red = palette[i].red;
+         this->green = palette[i].green;
+         this->blue = palette[i].blue;
+         this->alpha = palette[i].alpha;
+      }
+   }
+
+   else /* not palette */
+   {
+      unsigned int i = 0;
+
+      if ((colour_type & 4) != 0 && format != 0 && format->alpha_first)
+      {
+         this->alpha = this->red;
+         /* This handles the gray case for 'AG' pixels */
+         this->palette_index = this->red = this->green = this->blue =
+            sample(row, colour_type, bit_depth, x, 1, swap16, littleendian);
+         i = 1;
+      }
+
+      if (colour_type & 2)
+      {
+         /* Green is second for both BGR and RGB: */
+         this->green = sample(row, colour_type, bit_depth, x, ++i, swap16,
+                 littleendian);
+
+         if (format != 0 && format->swap_rgb) /* BGR */
+             this->red = sample(row, colour_type, bit_depth, x, ++i, swap16,
+                     littleendian);
+         else
+             this->blue = sample(row, colour_type, bit_depth, x, ++i, swap16,
+                     littleendian);
+      }
+
+      else /* grayscale */ if (format != 0 && format->mono_inverted)
+         this->red = this->green = this->blue = this->red ^ max;
+
+      if ((colour_type & 4) != 0) /* alpha */
+      {
+         if (format == 0 || !format->alpha_first)
+             this->alpha = sample(row, colour_type, bit_depth, x, ++i, swap16,
+                     littleendian);
+
+         if (format != 0 && format->alpha_inverted)
+            this->alpha ^= max;
+      }
+   }
+
+   /* Calculate the scaled values, these are simply the values divided by
+    * 'max' and the error is initialized to the double precision epsilon value
+    * from the header file.
+    */
+   image_pixel_setf(this,
+      sig_bits ? (1U << format->red_sBIT)-1 : max,
+      sig_bits ? (1U << format->green_sBIT)-1 : max,
+      sig_bits ? (1U << format->blue_sBIT)-1 : max,
+      sig_bits ? (1U << format->alpha_sBIT)-1 : max);
+
+   /* Store the input information for use in the transforms - these will
+    * modify the information.
+    */
+   this->colour_type = colour_type;
+   this->bit_depth = bit_depth;
+   this->sample_depth = sample_depth;
+   this->have_tRNS = 0;
+   this->swap_rgb = 0;
+   this->alpha_first = 0;
+   this->alpha_inverted = 0;
+   this->mono_inverted = 0;
+   this->swap16 = 0;
+   this->littleendian = 0;
+   this->sig_bits = 0;
+}
+
+#if defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_GRAY_TO_RGB_SUPPORTED\
+   || defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_EXPAND_16_SUPPORTED\
+   || defined PNG_READ_BACKGROUND_SUPPORTED
+/* Convert a palette image to an rgb image.  This necessarily converts the tRNS
+ * chunk at the same time, because the tRNS will be in palette form.  The way
+ * palette validation works means that the original palette is never updated,
+ * instead the image_pixel value from the row contains the RGB of the
+ * corresponding palette entry and *this* is updated.  Consequently this routine
+ * only needs to change the colour type information.
+ */
+static void
+image_pixel_convert_PLTE(image_pixel *this)
+{
+   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (this->have_tRNS)
+      {
+         this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+         this->have_tRNS = 0;
+      }
+      else
+         this->colour_type = PNG_COLOR_TYPE_RGB;
+
+      /* The bit depth of the row changes at this point too (notice that this is
+       * the row format, not the sample depth, which is separate.)
+       */
+      this->bit_depth = 8;
+   }
+}
+
+/* Add an alpha channel; this will import the tRNS information because tRNS is
+ * not valid in an alpha image.  The bit depth will invariably be set to at
+ * least 8 prior to 1.7.0.  Palette images will be converted to alpha (using
+ * the above API).  With png_set_background the alpha channel is never expanded
+ * but this routine is used by pngvalid to simplify code; 'for_background'
+ * records this.
+ */
+static void
+image_pixel_add_alpha(image_pixel *this, const standard_display *display,
+   int for_background)
+{
+   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(this);
+
+   if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
+   {
+      if (this->colour_type == PNG_COLOR_TYPE_GRAY)
+      {
+#        if PNG_LIBPNG_VER < 10700
+            if (!for_background && this->bit_depth < 8)
+               this->bit_depth = this->sample_depth = 8;
+#        endif
+
+         if (this->have_tRNS)
+         {
+            /* After 1.7 the expansion of bit depth only happens if there is a
+             * tRNS chunk to expand at this point.
+             */
+#           if PNG_LIBPNG_VER >= 10700
+               if (!for_background && this->bit_depth < 8)
+                  this->bit_depth = this->sample_depth = 8;
+#           endif
+
+            this->have_tRNS = 0;
+
+            /* Check the input, original, channel value here against the
+             * original tRNS gray chunk valie.
+             */
+            if (this->red == display->transparent.red)
+               this->alphaf = 0;
+            else
+               this->alphaf = 1;
+         }
+         else
+            this->alphaf = 1;
+
+         this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+      }
+
+      else if (this->colour_type == PNG_COLOR_TYPE_RGB)
+      {
+         if (this->have_tRNS)
+         {
+            this->have_tRNS = 0;
+
+            /* Again, check the exact input values, not the current transformed
+             * value!
+             */
+            if (this->red == display->transparent.red &&
+               this->green == display->transparent.green &&
+               this->blue == display->transparent.blue)
+               this->alphaf = 0;
+            else
+               this->alphaf = 1;
+         }
+         else
+            this->alphaf = 1;
+
+         this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+      }
+
+      /* The error in the alpha is zero and the sBIT value comes from the
+       * original sBIT data (actually it will always be the original bit depth).
+       */
+      this->alphae = 0;
+      this->alpha_sBIT = display->alpha_sBIT;
+   }
+}
+#endif /* transforms that need image_pixel_add_alpha */
+
+struct transform_display;
+typedef struct image_transform
+{
+   /* The name of this transform: a string. */
+   const char *name;
+
+   /* Each transform can be disabled from the command line: */
+   int enable;
+
+   /* The global list of transforms; read only. */
+   struct image_transform *const list;
+
+   /* The global count of the number of times this transform has been set on an
+    * image.
+    */
+   unsigned int global_use;
+
+   /* The local count of the number of times this transform has been set. */
+   unsigned int local_use;
+
+   /* The next transform in the list, each transform must call its own next
+    * transform after it has processed the pixel successfully.
+    */
+   const struct image_transform *next;
+
+   /* A single transform for the image, expressed as a series of function
+    * callbacks and some space for values.
+    *
+    * First a callback to add any required modifications to the png_modifier;
+    * this gets called just before the modifier is set up for read.
+    */
+   void (*ini)(const struct image_transform *this,
+      struct transform_display *that);
+
+   /* And a callback to set the transform on the current png_read_struct:
+    */
+   void (*set)(const struct image_transform *this,
+      struct transform_display *that, png_structp pp, png_infop pi);
+
+   /* Then a transform that takes an input pixel in one PNG format or another
+    * and modifies it by a pngvalid implementation of the transform (thus
+    * duplicating the libpng intent without, we hope, duplicating the bugs
+    * in the libpng implementation!)  The png_structp is solely to allow error
+    * reporting via png_error and png_warning.
+    */
+   void (*mod)(const struct image_transform *this, image_pixel *that,
+      png_const_structp pp, const struct transform_display *display);
+
+   /* Add this transform to the list and return true if the transform is
+    * meaningful for this colour type and bit depth - if false then the
+    * transform should have no effect on the image so there's not a lot of
+    * point running it.
+    */
+   int (*add)(struct image_transform *this,
+      const struct image_transform **that, png_byte colour_type,
+      png_byte bit_depth);
+} image_transform;
+
+typedef struct transform_display
+{
+   standard_display this;
+
+   /* Parameters */
+   png_modifier*              pm;
+   const image_transform* transform_list;
+   unsigned int max_gamma_8;
+
+   /* Local variables */
+   png_byte output_colour_type;
+   png_byte output_bit_depth;
+   png_byte unpacked;
+
+   /* Modifications (not necessarily used.) */
+   gama_modification gama_mod;
+   chrm_modification chrm_mod;
+   srgb_modification srgb_mod;
+} transform_display;
+
+/* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
+static void
+transform_set_encoding(transform_display *this)
+{
+   /* Set up the png_modifier '_current' fields then use these to determine how
+    * to add appropriate chunks.
+    */
+   png_modifier *pm = this->pm;
+
+   modifier_set_encoding(pm);
+
+   if (modifier_color_encoding_is_set(pm))
+   {
+      if (modifier_color_encoding_is_sRGB(pm))
+         srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
+
+      else
+      {
+         /* Set gAMA and cHRM separately. */
+         gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
+
+         if (pm->current_encoding != 0)
+            chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
+      }
+   }
+}
+
+/* Three functions to end the list: */
+static void
+image_transform_ini_end(const image_transform *this,
+   transform_display *that)
+{
+   UNUSED(this)
+   UNUSED(that)
+}
+
+static void
+image_transform_set_end(const image_transform *this,
+   transform_display *that, png_structp pp, png_infop pi)
+{
+   UNUSED(this)
+   UNUSED(that)
+   UNUSED(pp)
+   UNUSED(pi)
+}
+
+/* At the end of the list recalculate the output image pixel value from the
+ * double precision values set up by the preceding 'mod' calls:
+ */
+static unsigned int
+sample_scale(double sample_value, unsigned int scale)
+{
+   sample_value = floor(sample_value * scale + .5);
+
+   /* Return NaN as 0: */
+   if (!(sample_value > 0))
+      sample_value = 0;
+   else if (sample_value > scale)
+      sample_value = scale;
+
+   return (unsigned int)sample_value;
+}
+
+static void
+image_transform_mod_end(const image_transform *this, image_pixel *that,
+    png_const_structp pp, const transform_display *display)
+{
+   unsigned int scale = (1U<<that->sample_depth)-1;
+   int sig_bits = that->sig_bits;
+
+   UNUSED(this)
+   UNUSED(pp)
+   UNUSED(display)
+
+   /* At the end recalculate the digitized red green and blue values according
+    * to the current sample_depth of the pixel.
+    *
+    * The sample value is simply scaled to the maximum, checking for over
+    * and underflow (which can both happen for some image transforms,
+    * including simple size scaling, though libpng doesn't do that at present.
+    */
+   that->red = sample_scale(that->redf, scale);
+
+   /* This is a bit bogus; really the above calculation should use the red_sBIT
+    * value, not sample_depth, but because libpng does png_set_shift by just
+    * shifting the bits we get errors if we don't do it the same way.
+    */
+   if (sig_bits && that->red_sBIT < that->sample_depth)
+      that->red >>= that->sample_depth - that->red_sBIT;
+
+   /* The error value is increased, at the end, according to the lowest sBIT
+    * value seen.  Common sense tells us that the intermediate integer
+    * representations are no more accurate than +/- 0.5 in the integral values,
+    * the sBIT allows the implementation to be worse than this.  In addition the
+    * PNG specification actually permits any error within the range (-1..+1),
+    * but that is ignored here.  Instead the final digitized value is compared,
+    * below to the digitized value of the error limits - this has the net effect
+    * of allowing (almost) +/-1 in the output value.  It's difficult to see how
+    * any algorithm that digitizes intermediate results can be more accurate.
+    */
+   that->rede += 1./(2*((1U<<that->red_sBIT)-1));
+
+   if (that->colour_type & PNG_COLOR_MASK_COLOR)
+   {
+      that->green = sample_scale(that->greenf, scale);
+      if (sig_bits && that->green_sBIT < that->sample_depth)
+         that->green >>= that->sample_depth - that->green_sBIT;
+
+      that->blue = sample_scale(that->bluef, scale);
+      if (sig_bits && that->blue_sBIT < that->sample_depth)
+         that->blue >>= that->sample_depth - that->blue_sBIT;
+
+      that->greene += 1./(2*((1U<<that->green_sBIT)-1));
+      that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
+   }
+   else
+   {
+      that->blue = that->green = that->red;
+      that->bluef = that->greenf = that->redf;
+      that->bluee = that->greene = that->rede;
+   }
+
+   if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
+      that->colour_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      that->alpha = sample_scale(that->alphaf, scale);
+      that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
+   }
+   else
+   {
+      that->alpha = scale; /* opaque */
+      that->alphaf = 1;    /* Override this. */
+      that->alphae = 0;    /* It's exact ;-) */
+   }
+
+   if (sig_bits && that->alpha_sBIT < that->sample_depth)
+      that->alpha >>= that->sample_depth - that->alpha_sBIT;
+}
+
+/* Static 'end' structure: */
+static image_transform image_transform_end =
+{
+   "(end)", /* name */
+   1, /* enable */
+   0, /* list */
+   0, /* global_use */
+   0, /* local_use */
+   0, /* next */
+   image_transform_ini_end,
+   image_transform_set_end,
+   image_transform_mod_end,
+   0 /* never called, I want it to crash if it is! */
+};
+
+/* Reader callbacks and implementations, where they differ from the standard
+ * ones.
+ */
+static void
+transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
+    const image_transform *transform_list)
+{
+   memset(dp, 0, sizeof *dp);
+
+   /* Standard fields */
+   standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
+      pm->use_update_info);
+
+   /* Parameter fields */
+   dp->pm = pm;
+   dp->transform_list = transform_list;
+   dp->max_gamma_8 = 16;
+
+   /* Local variable fields */
+   dp->output_colour_type = 255; /* invalid */
+   dp->output_bit_depth = 255;  /* invalid */
+   dp->unpacked = 0; /* not unpacked */
+}
+
+static void
+transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
+{
+   /* Reuse the standard stuff as appropriate. */
+   standard_info_part1(&dp->this, pp, pi);
+
+   /* Now set the list of transforms. */
+   dp->transform_list->set(dp->transform_list, dp, pp, pi);
+
+   /* Update the info structure for these transforms: */
+   {
+      int i = dp->this.use_update_info;
+      /* Always do one call, even if use_update_info is 0. */
+      do
+         png_read_update_info(pp, pi);
+      while (--i > 0);
+   }
+
+   /* And get the output information into the standard_display */
+   standard_info_part2(&dp->this, pp, pi, 1/*images*/);
+
+   /* Plus the extra stuff we need for the transform tests: */
+   dp->output_colour_type = png_get_color_type(pp, pi);
+   dp->output_bit_depth = png_get_bit_depth(pp, pi);
+
+   /* If png_set_filler is in action then fake the output color type to include
+    * an alpha channel where appropriate.
+    */
+   if (dp->output_bit_depth >= 8 &&
+       (dp->output_colour_type == PNG_COLOR_TYPE_RGB ||
+        dp->output_colour_type == PNG_COLOR_TYPE_GRAY) && dp->this.filler)
+       dp->output_colour_type |= 4;
+
+   /* Validate the combination of colour type and bit depth that we are getting
+    * out of libpng; the semantics of something not in the PNG spec are, at
+    * best, unclear.
+    */
+   switch (dp->output_colour_type)
+   {
+   case PNG_COLOR_TYPE_PALETTE:
+      if (dp->output_bit_depth > 8) goto error;
+      /* FALLTHROUGH */
+   case PNG_COLOR_TYPE_GRAY:
+      if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
+         dp->output_bit_depth == 4)
+         break;
+      /* FALLTHROUGH */
+   default:
+      if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
+         break;
+      /* FALLTHROUGH */
+   error:
+      {
+         char message[128];
+         size_t pos;
+
+         pos = safecat(message, sizeof message, 0,
+            "invalid final bit depth: colour type(");
+         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
+         pos = safecat(message, sizeof message, pos, ") with bit depth: ");
+         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+
+         png_error(pp, message);
+      }
+   }
+
+   /* Use a test pixel to check that the output agrees with what we expect -
+    * this avoids running the whole test if the output is unexpected.  This also
+    * checks for internal errors.
+    */
+   {
+      image_pixel test_pixel;
+
+      memset(&test_pixel, 0, sizeof test_pixel);
+      test_pixel.colour_type = dp->this.colour_type; /* input */
+      test_pixel.bit_depth = dp->this.bit_depth;
+      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
+         test_pixel.sample_depth = 8;
+      else
+         test_pixel.sample_depth = test_pixel.bit_depth;
+      /* Don't need sBIT here, but it must be set to non-zero to avoid
+       * arithmetic overflows.
+       */
+      test_pixel.have_tRNS = dp->this.is_transparent != 0;
+      test_pixel.red_sBIT = test_pixel.green_sBIT = test_pixel.blue_sBIT =
+         test_pixel.alpha_sBIT = test_pixel.sample_depth;
+
+      dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
+
+      if (test_pixel.colour_type != dp->output_colour_type)
+      {
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0, "colour type ");
+
+         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
+
+         png_error(pp, message);
+      }
+
+      if (test_pixel.bit_depth != dp->output_bit_depth)
+      {
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0, "bit depth ");
+
+         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
+
+         png_error(pp, message);
+      }
+
+      /* If both bit depth and colour type are correct check the sample depth.
+       */
+      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE &&
+          test_pixel.sample_depth != 8) /* oops - internal error! */
+         png_error(pp, "pngvalid: internal: palette sample depth not 8");
+      else if (dp->unpacked && test_pixel.bit_depth != 8)
+         png_error(pp, "pngvalid: internal: bad unpacked pixel depth");
+      else if (!dp->unpacked && test_pixel.colour_type != PNG_COLOR_TYPE_PALETTE
+              && test_pixel.bit_depth != test_pixel.sample_depth)
+      {
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0,
+            "internal: sample depth ");
+
+         /* Because unless something has set 'unpacked' or the image is palette
+          * mapped we expect the transform to keep sample depth and bit depth
+          * the same.
+          */
+         pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
+
+         png_error(pp, message);
+      }
+      else if (test_pixel.bit_depth != dp->output_bit_depth)
+      {
+         /* This could be a libpng error too; libpng has not produced what we
+          * expect for the output bit depth.
+          */
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0,
+            "internal: bit depth ");
+
+         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
+
+         png_error(pp, message);
+      }
+   }
+}
+
+static void PNGCBAPI
+transform_info(png_structp pp, png_infop pi)
+{
+   transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
+      pp, pi);
+}
+
+static void
+transform_range_check(png_const_structp pp, unsigned int r, unsigned int g,
+   unsigned int b, unsigned int a, unsigned int in_digitized, double in,
+   unsigned int out, png_byte sample_depth, double err, double limit,
+   const char *name, double digitization_error)
+{
+   /* Compare the scaled, digitized, values of our local calculation (in+-err)
+    * with the digitized values libpng produced;  'sample_depth' is the actual
+    * digitization depth of the libpng output colors (the bit depth except for
+    * palette images where it is always 8.)  The check on 'err' is to detect
+    * internal errors in pngvalid itself.
+    */
+   unsigned int max = (1U<<sample_depth)-1;
+   double in_min = ceil((in-err)*max - digitization_error);
+   double in_max = floor((in+err)*max + digitization_error);
+   if (debugonly(err > limit ||) !(out >= in_min && out <= in_max))
+   {
+      char message[256];
+      size_t pos;
+
+      pos = safecat(message, sizeof message, 0, name);
+      pos = safecat(message, sizeof message, pos, " output value error: rgba(");
+      pos = safecatn(message, sizeof message, pos, r);
+      pos = safecat(message, sizeof message, pos, ",");
+      pos = safecatn(message, sizeof message, pos, g);
+      pos = safecat(message, sizeof message, pos, ",");
+      pos = safecatn(message, sizeof message, pos, b);
+      pos = safecat(message, sizeof message, pos, ",");
+      pos = safecatn(message, sizeof message, pos, a);
+      pos = safecat(message, sizeof message, pos, "): ");
+      pos = safecatn(message, sizeof message, pos, out);
+      pos = safecat(message, sizeof message, pos, " expected: ");
+      pos = safecatn(message, sizeof message, pos, in_digitized);
+      pos = safecat(message, sizeof message, pos, " (");
+      pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
+      pos = safecat(message, sizeof message, pos, "..");
+      pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
+      pos = safecat(message, sizeof message, pos, ")");
+
+      png_error(pp, message);
+   }
+
+   UNUSED(limit)
+}
+
+static void
+transform_image_validate(transform_display *dp, png_const_structp pp,
+   png_infop pi)
+{
+   /* Constants for the loop below: */
+   const png_store* const ps = dp->this.ps;
+   png_byte in_ct = dp->this.colour_type;
+   png_byte in_bd = dp->this.bit_depth;
+   png_uint_32 w = dp->this.w;
+   png_uint_32 h = dp->this.h;
+   png_byte out_ct = dp->output_colour_type;
+   png_byte out_bd = dp->output_bit_depth;
+   png_byte sample_depth =
+      (png_byte)(out_ct == PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
+   png_byte red_sBIT = dp->this.red_sBIT;
+   png_byte green_sBIT = dp->this.green_sBIT;
+   png_byte blue_sBIT = dp->this.blue_sBIT;
+   png_byte alpha_sBIT = dp->this.alpha_sBIT;
+   int have_tRNS = dp->this.is_transparent;
+   double digitization_error;
+
+   store_palette out_palette;
+   png_uint_32 y;
+
+   UNUSED(pi)
+
+   /* Check for row overwrite errors */
+   store_image_check(dp->this.ps, pp, 0);
+
+   /* Read the palette corresponding to the output if the output colour type
+    * indicates a palette, otherwise set out_palette to garbage.
+    */
+   if (out_ct == PNG_COLOR_TYPE_PALETTE)
+   {
+      /* Validate that the palette count itself has not changed - this is not
+       * expected.
+       */
+      int npalette = (-1);
+
+      (void)read_palette(out_palette, &npalette, pp, pi);
+      if (npalette != dp->this.npalette)
+         png_error(pp, "unexpected change in palette size");
+
+      digitization_error = .5;
+   }
+   else
+   {
+      png_byte in_sample_depth;
+
+      memset(out_palette, 0x5e, sizeof out_palette);
+
+      /* use-input-precision means assume that if the input has 8 bit (or less)
+       * samples and the output has 16 bit samples the calculations will be done
+       * with 8 bit precision, not 16.
+       */
+      if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
+         in_sample_depth = 8;
+      else
+         in_sample_depth = in_bd;
+
+      if (sample_depth != 16 || in_sample_depth > 8 ||
+         !dp->pm->calculations_use_input_precision)
+         digitization_error = .5;
+
+      /* Else calculations are at 8 bit precision, and the output actually
+       * consists of scaled 8-bit values, so scale .5 in 8 bits to the 16 bits:
+       */
+      else
+         digitization_error = .5 * 257;
+   }
+
+   for (y=0; y<h; ++y)
+   {
+      png_const_bytep const pRow = store_image_row(ps, pp, 0, y);
+      png_uint_32 x;
+
+      /* The original, standard, row pre-transforms. */
+      png_byte std[STANDARD_ROWMAX];
+
+      transform_row(pp, std, in_ct, in_bd, y);
+
+      /* Go through each original pixel transforming it and comparing with what
+       * libpng did to the same pixel.
+       */
+      for (x=0; x<w; ++x)
+      {
+         image_pixel in_pixel, out_pixel;
+         unsigned int r, g, b, a;
+
+         /* Find out what we think the pixel should be: */
+         image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette,
+                 NULL);
+
+         in_pixel.red_sBIT = red_sBIT;
+         in_pixel.green_sBIT = green_sBIT;
+         in_pixel.blue_sBIT = blue_sBIT;
+         in_pixel.alpha_sBIT = alpha_sBIT;
+         in_pixel.have_tRNS = have_tRNS != 0;
+
+         /* For error detection, below. */
+         r = in_pixel.red;
+         g = in_pixel.green;
+         b = in_pixel.blue;
+         a = in_pixel.alpha;
+
+         /* This applies the transforms to the input data, including output
+          * format operations which must be used when reading the output
+          * pixel that libpng produces.
+          */
+         dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
+
+         /* Read the output pixel and compare it to what we got, we don't
+          * use the error field here, so no need to update sBIT.  in_pixel
+          * says whether we expect libpng to change the output format.
+          */
+         image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette,
+                 &in_pixel);
+
+         /* We don't expect changes to the index here even if the bit depth is
+          * changed.
+          */
+         if (in_ct == PNG_COLOR_TYPE_PALETTE &&
+            out_ct == PNG_COLOR_TYPE_PALETTE)
+         {
+            if (in_pixel.palette_index != out_pixel.palette_index)
+               png_error(pp, "unexpected transformed palette index");
+         }
+
+         /* Check the colours for palette images too - in fact the palette could
+          * be separately verified itself in most cases.
+          */
+         if (in_pixel.red != out_pixel.red)
+            transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
+               out_pixel.red, sample_depth, in_pixel.rede,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
+               digitization_error);
+
+         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
+            in_pixel.green != out_pixel.green)
+            transform_range_check(pp, r, g, b, a, in_pixel.green,
+               in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
+               digitization_error);
+
+         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
+            in_pixel.blue != out_pixel.blue)
+            transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
+               out_pixel.blue, sample_depth, in_pixel.bluee,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
+               digitization_error);
+
+         if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
+            in_pixel.alpha != out_pixel.alpha)
+            transform_range_check(pp, r, g, b, a, in_pixel.alpha,
+               in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
+               digitization_error);
+      } /* pixel (x) loop */
+   } /* row (y) loop */
+
+   /* Record that something was actually checked to avoid a false positive. */
+   dp->this.ps->validated = 1;
+}
+
+static void PNGCBAPI
+transform_end(png_structp ppIn, png_infop pi)
+{
+   png_const_structp pp = ppIn;
+   transform_display *dp = voidcast(transform_display*,
+      png_get_progressive_ptr(pp));
+
+   if (!dp->this.speed)
+      transform_image_validate(dp, pp, pi);
+   else
+      dp->this.ps->validated = 1;
+}
+
+/* A single test run. */
+static void
+transform_test(png_modifier *pmIn, png_uint_32 idIn,
+    const image_transform* transform_listIn, const char * const name)
+{
+   transform_display d;
+   context(&pmIn->this, fault);
+
+   transform_display_init(&d, pmIn, idIn, transform_listIn);
+
+   Try
+   {
+      size_t pos = 0;
+      png_structp pp;
+      png_infop pi;
+      char full_name[256];
+
+      /* Make sure the encoding fields are correct and enter the required
+       * modifications.
+       */
+      transform_set_encoding(&d);
+
+      /* Add any modifications required by the transform list. */
+      d.transform_list->ini(d.transform_list, &d);
+
+      /* Add the color space information, if any, to the name. */
+      pos = safecat(full_name, sizeof full_name, pos, name);
+      pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
+
+      /* Get a png_struct for reading the image. */
+      pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
+      standard_palette_init(&d.this);
+
+#     if 0
+         /* Logging (debugging only) */
+         {
+            char buffer[256];
+
+            (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
+               "running test");
+
+            fprintf(stderr, "%s\n", buffer);
+         }
+#     endif
+
+      /* Introduce the correct read function. */
+      if (d.pm->this.progressive)
+      {
+         /* Share the row function with the standard implementation. */
+         png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
+            transform_end);
+
+         /* Now feed data into the reader until we reach the end: */
+         modifier_progressive_read(d.pm, pp, pi);
+      }
+      else
+      {
+         /* modifier_read expects a png_modifier* */
+         png_set_read_fn(pp, d.pm, modifier_read);
+
+         /* Check the header values: */
+         png_read_info(pp, pi);
+
+         /* Process the 'info' requirements. Only one image is generated */
+         transform_info_imp(&d, pp, pi);
+
+         sequential_row(&d.this, pp, pi, -1, 0);
+
+         if (!d.this.speed)
+            transform_image_validate(&d, pp, pi);
+         else
+            d.this.ps->validated = 1;
+      }
+
+      modifier_reset(d.pm);
+   }
+
+   Catch(fault)
+   {
+      modifier_reset(voidcast(png_modifier*,(void*)fault));
+   }
+}
+
+/* The transforms: */
+#define ITSTRUCT(name) image_transform_##name
+#define ITDATA(name) image_transform_data_##name
+#define image_transform_ini image_transform_default_ini
+#define IT(name)\
+static image_transform ITSTRUCT(name) =\
+{\
+   #name,\
+   1, /*enable*/\
+   &PT, /*list*/\
+   0, /*global_use*/\
+   0, /*local_use*/\
+   0, /*next*/\
+   image_transform_ini,\
+   image_transform_png_set_##name##_set,\
+   image_transform_png_set_##name##_mod,\
+   image_transform_png_set_##name##_add\
+}
+#define PT ITSTRUCT(end) /* stores the previous transform */
+
+/* To save code: */
+extern void image_transform_default_ini(const image_transform *this,
+   transform_display *that); /* silence GCC warnings */
+
+void /* private, but almost always needed */
+image_transform_default_ini(const image_transform *this,
+    transform_display *that)
+{
+   this->next->ini(this->next, that);
+}
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+static int
+image_transform_default_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return 1;
+}
+#endif
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_palette_to_rgb */
+static void
+image_transform_png_set_palette_to_rgb_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_palette_to_rgb(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_palette_to_rgb_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_palette_to_rgb_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return colour_type == PNG_COLOR_TYPE_PALETTE;
+}
+
+IT(palette_to_rgb);
+#undef PT
+#define PT ITSTRUCT(palette_to_rgb)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_tRNS_to_alpha */
+static void
+image_transform_png_set_tRNS_to_alpha_set(const image_transform *this,
+   transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_tRNS_to_alpha(pp);
+
+   /* If there was a tRNS chunk that would get expanded and add an alpha
+    * channel is_transparent must be updated:
+    */
+   if (that->this.has_tRNS)
+      that->this.is_transparent = 1;
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_tRNS_to_alpha_mod(const image_transform *this,
+   image_pixel *that, png_const_structp pp,
+   const transform_display *display)
+{
+#if PNG_LIBPNG_VER < 10700
+   /* LIBPNG BUG: this always forces palette images to RGB. */
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+#endif
+
+   /* This effectively does an 'expand' only if there is some transparency to
+    * convert to an alpha channel.
+    */
+   if (that->have_tRNS)
+#     if PNG_LIBPNG_VER >= 10700
+         if (that->colour_type != PNG_COLOR_TYPE_PALETTE &&
+             (that->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
+#     endif
+      image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
+
+#if PNG_LIBPNG_VER < 10700
+   /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
+   else
+   {
+      if (that->bit_depth < 8)
+         that->bit_depth =8;
+      if (that->sample_depth < 8)
+         that->sample_depth = 8;
+   }
+#endif
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* We don't know yet whether there will be a tRNS chunk, but we know that
+    * this transformation should do nothing if there already is an alpha
+    * channel.  In addition, after the bug fix in 1.7.0, there is no longer
+    * any action on a palette image.
+    */
+   return
+#  if PNG_LIBPNG_VER >= 10700
+      colour_type != PNG_COLOR_TYPE_PALETTE &&
+#  endif
+   (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
+}
+
+IT(tRNS_to_alpha);
+#undef PT
+#define PT ITSTRUCT(tRNS_to_alpha)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* png_set_gray_to_rgb */
+static void
+image_transform_png_set_gray_to_rgb_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_gray_to_rgb(pp);
+   /* NOTE: this doesn't result in tRNS expansion. */
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_gray_to_rgb_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* NOTE: we can actually pend the tRNS processing at this point because we
+    * can correctly recognize the original pixel value even though we have
+    * mapped the one gray channel to the three RGB ones, but in fact libpng
+    * doesn't do this, so we don't either.
+    */
+   if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
+
+   /* Simply expand the bit depth and alter the colour type as required. */
+   if (that->colour_type == PNG_COLOR_TYPE_GRAY)
+   {
+      /* RGB images have a bit depth at least equal to '8' */
+      if (that->bit_depth < 8)
+         that->sample_depth = that->bit_depth = 8;
+
+      /* And just changing the colour type works here because the green and blue
+       * channels are being maintained in lock-step with the red/gray:
+       */
+      that->colour_type = PNG_COLOR_TYPE_RGB;
+   }
+
+   else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_gray_to_rgb_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
+}
+
+IT(gray_to_rgb);
+#undef PT
+#define PT ITSTRUCT(gray_to_rgb)
+#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_expand */
+static void
+image_transform_png_set_expand_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_expand(pp);
+
+   if (that->this.has_tRNS)
+      that->this.is_transparent = 1;
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* The general expand case depends on what the colour type is: */
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+   else if (that->bit_depth < 8) /* grayscale */
+      that->sample_depth = that->bit_depth = 8;
+
+   if (that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_expand_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
+    * depth is at least 8 already.
+    */
+   return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
+}
+
+IT(expand);
+#undef PT
+#define PT ITSTRUCT(expand)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_expand_gray_1_2_4_to_8
+ * Pre 1.7.0 LIBPNG BUG: this just does an 'expand'
+ */
+static void
+image_transform_png_set_expand_gray_1_2_4_to_8_set(
+    const image_transform *this, transform_display *that, png_structp pp,
+    png_infop pi)
+{
+   png_set_expand_gray_1_2_4_to_8(pp);
+   /* NOTE: don't expect this to expand tRNS */
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_gray_1_2_4_to_8_mod(
+    const image_transform *this, image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+#if PNG_LIBPNG_VER < 10700
+   image_transform_png_set_expand_mod(this, that, pp, display);
+#else
+   /* Only expand grayscale of bit depth less than 8: */
+   if (that->colour_type == PNG_COLOR_TYPE_GRAY &&
+       that->bit_depth < 8)
+      that->sample_depth = that->bit_depth = 8;
+
+   this->next->mod(this->next, that, pp, display);
+#endif /* 1.7 or later */
+}
+
+static int
+image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+#if PNG_LIBPNG_VER < 10700
+   return image_transform_png_set_expand_add(this, that, colour_type,
+      bit_depth);
+#else
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* This should do nothing unless the color type is gray and the bit depth is
+    * less than 8:
+    */
+   return colour_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8;
+#endif /* 1.7 or later */
+}
+
+IT(expand_gray_1_2_4_to_8);
+#undef PT
+#define PT ITSTRUCT(expand_gray_1_2_4_to_8)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* png_set_expand_16 */
+static void
+image_transform_png_set_expand_16_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_expand_16(pp);
+
+   /* NOTE: prior to 1.7 libpng does SET_EXPAND as well, so tRNS is expanded. */
+#  if PNG_LIBPNG_VER < 10700
+      if (that->this.has_tRNS)
+         that->this.is_transparent = 1;
+#  endif
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_16_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* Expect expand_16 to expand everything to 16 bits as a result of also
+    * causing 'expand' to happen.
+    */
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+
+   if (that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
+
+   if (that->bit_depth < 16)
+      that->sample_depth = that->bit_depth = 16;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_expand_16_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   /* expand_16 does something unless the bit depth is already 16. */
+   return bit_depth < 16;
+}
+
+IT(expand_16);
+#undef PT
+#define PT ITSTRUCT(expand_16)
+#endif /* PNG_READ_EXPAND_16_SUPPORTED */
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED  /* API added in 1.5.4 */
+/* png_set_scale_16 */
+static void
+image_transform_png_set_scale_16_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_scale_16(pp);
+#  if PNG_LIBPNG_VER < 10700
+      /* libpng will limit the gamma table size: */
+      that->max_gamma_8 = PNG_MAX_GAMMA_8;
+#  endif
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_scale_16_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth == 16)
+   {
+      that->sample_depth = that->bit_depth = 8;
+      if (that->red_sBIT > 8) that->red_sBIT = 8;
+      if (that->green_sBIT > 8) that->green_sBIT = 8;
+      if (that->blue_sBIT > 8) that->blue_sBIT = 8;
+      if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_scale_16_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   return bit_depth > 8;
+}
+
+IT(scale_16);
+#undef PT
+#define PT ITSTRUCT(scale_16)
+#endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
+
+#ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
+/* png_set_strip_16 */
+static void
+image_transform_png_set_strip_16_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_strip_16(pp);
+#  if PNG_LIBPNG_VER < 10700
+      /* libpng will limit the gamma table size: */
+      that->max_gamma_8 = PNG_MAX_GAMMA_8;
+#  endif
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_strip_16_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth == 16)
+   {
+      that->sample_depth = that->bit_depth = 8;
+      if (that->red_sBIT > 8) that->red_sBIT = 8;
+      if (that->green_sBIT > 8) that->green_sBIT = 8;
+      if (that->blue_sBIT > 8) that->blue_sBIT = 8;
+      if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
+
+      /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
+       * configuration option is set.  From 1.5.4 the flag is never set and the
+       * 'scale' API (above) must be used.
+       */
+#     ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
+#        if PNG_LIBPNG_VER >= 10504
+#           error PNG_READ_ACCURATE_SCALE should not be set
+#        endif
+
+         /* The strip 16 algorithm drops the low 8 bits rather than calculating
+          * 1/257, so we need to adjust the permitted errors appropriately:
+          * Notice that this is only relevant prior to the addition of the
+          * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
+          */
+         {
+            const double d = (255-128.5)/65535;
+            that->rede += d;
+            that->greene += d;
+            that->bluee += d;
+            that->alphae += d;
+         }
+#     endif
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_strip_16_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   return bit_depth > 8;
+}
+
+IT(strip_16);
+#undef PT
+#define PT ITSTRUCT(strip_16)
+#endif /* PNG_READ_16_TO_8_SUPPORTED */
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+/* png_set_strip_alpha */
+static void
+image_transform_png_set_strip_alpha_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_strip_alpha(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_strip_alpha_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_GRAY;
+   else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_RGB;
+
+   that->have_tRNS = 0;
+   that->alphaf = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_strip_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
+}
+
+IT(strip_alpha);
+#undef PT
+#define PT ITSTRUCT(strip_alpha)
+#endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
+ * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
+ *    png_fixed_point green)
+ * png_get_rgb_to_gray_status
+ *
+ * The 'default' test here uses values known to be used inside libpng prior to
+ * 1.7.0:
+ *
+ *   red:    6968
+ *   green: 23434
+ *   blue:   2366
+ *
+ * These values are being retained for compatibility, along with the somewhat
+ * broken truncation calculation in the fast-and-inaccurate code path.  Older
+ * versions of libpng will fail the accuracy tests below because they use the
+ * truncation algorithm everywhere.
+ */
+#define data ITDATA(rgb_to_gray)
+static struct
+{
+   double gamma;      /* File gamma to use in processing */
+
+   /* The following are the parameters for png_set_rgb_to_gray: */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+      double red_to_set;
+      double green_to_set;
+#  else
+      png_fixed_point red_to_set;
+      png_fixed_point green_to_set;
+#  endif
+
+   /* The actual coefficients: */
+   double red_coefficient;
+   double green_coefficient;
+   double blue_coefficient;
+
+   /* Set if the coeefficients have been overridden. */
+   int coefficients_overridden;
+} data;
+
+#undef image_transform_ini
+#define image_transform_ini image_transform_png_set_rgb_to_gray_ini
+static void
+image_transform_png_set_rgb_to_gray_ini(const image_transform *this,
+    transform_display *that)
+{
+   png_modifier *pm = that->pm;
+   const color_encoding *e = pm->current_encoding;
+
+   UNUSED(this)
+
+   /* Since we check the encoding this flag must be set: */
+   pm->test_uses_encoding = 1;
+
+   /* If 'e' is not NULL chromaticity information is present and either a cHRM
+    * or an sRGB chunk will be inserted.
+    */
+   if (e != 0)
+   {
+      /* Coefficients come from the encoding, but may need to be normalized to a
+       * white point Y of 1.0
+       */
+      const double whiteY = e->red.Y + e->green.Y + e->blue.Y;
+
+      data.red_coefficient = e->red.Y;
+      data.green_coefficient = e->green.Y;
+      data.blue_coefficient = e->blue.Y;
+
+      if (whiteY != 1)
+      {
+         data.red_coefficient /= whiteY;
+         data.green_coefficient /= whiteY;
+         data.blue_coefficient /= whiteY;
+      }
+   }
+
+   else
+   {
+      /* The default (built in) coefficients, as above: */
+#     if PNG_LIBPNG_VER < 10700
+         data.red_coefficient = 6968 / 32768.;
+         data.green_coefficient = 23434 / 32768.;
+         data.blue_coefficient = 2366 / 32768.;
+#     else
+         data.red_coefficient = .2126;
+         data.green_coefficient = .7152;
+         data.blue_coefficient = .0722;
+#     endif
+   }
+
+   data.gamma = pm->current_gamma;
+
+   /* If not set then the calculations assume linear encoding (implicitly): */
+   if (data.gamma == 0)
+      data.gamma = 1;
+
+   /* The arguments to png_set_rgb_to_gray can override the coefficients implied
+    * by the color space encoding.  If doing exhaustive checks do the override
+    * in each case, otherwise do it randomly.
+    */
+   if (pm->test_exhaustive)
+   {
+      /* First time in coefficients_overridden is 0, the following sets it to 1,
+       * so repeat if it is set.  If a test fails this may mean we subsequently
+       * skip a non-override test, ignore that.
+       */
+      data.coefficients_overridden = !data.coefficients_overridden;
+      pm->repeat = data.coefficients_overridden != 0;
+   }
+
+   else
+      data.coefficients_overridden = random_choice();
+
+   if (data.coefficients_overridden)
+   {
+      /* These values override the color encoding defaults, simply use random
+       * numbers.
+       */
+      png_uint_32 ru;
+      double total;
+
+      ru = random_u32();
+      data.green_coefficient = total = (ru & 0xffff) / 65535.;
+      ru >>= 16;
+      data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
+      total += data.red_coefficient;
+      data.blue_coefficient = 1 - total;
+
+#     ifdef PNG_FLOATING_POINT_SUPPORTED
+         data.red_to_set = data.red_coefficient;
+         data.green_to_set = data.green_coefficient;
+#     else
+         data.red_to_set = fix(data.red_coefficient);
+         data.green_to_set = fix(data.green_coefficient);
+#     endif
+
+      /* The following just changes the error messages: */
+      pm->encoding_ignored = 1;
+   }
+
+   else
+   {
+      data.red_to_set = -1;
+      data.green_to_set = -1;
+   }
+
+   /* Adjust the error limit in the png_modifier because of the larger errors
+    * produced in the digitization during the gamma handling.
+    */
+   if (data.gamma != 1) /* Use gamma tables */
+   {
+      if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
+      {
+         /* The computations have the form:
+          *
+          *    r * rc + g * gc + b * bc
+          *
+          *  Each component of which is +/-1/65535 from the gamma_to_1 table
+          *  lookup, resulting in a base error of +/-6.  The gamma_from_1
+          *  conversion adds another +/-2 in the 16-bit case and
+          *  +/-(1<<(15-PNG_MAX_GAMMA_8)) in the 8-bit case.
+          */
+#        if PNG_LIBPNG_VER < 10700
+            if (that->this.bit_depth < 16)
+               that->max_gamma_8 = PNG_MAX_GAMMA_8;
+#        endif
+         that->pm->limit += pow(
+            (that->this.bit_depth == 16 || that->max_gamma_8 > 14 ?
+               8. :
+               6. + (1<<(15-that->max_gamma_8))
+            )/65535, data.gamma);
+      }
+
+      else
+      {
+         /* Rounding to 8 bits in the linear space causes massive errors which
+          * will trigger the error check in transform_range_check.  Fix that
+          * here by taking the gamma encoding into account.
+          *
+          * When DIGITIZE is set because a pre-1.7 version of libpng is being
+          * tested allow a bigger slack.
+          *
+          * NOTE: this number only affects the internal limit check in pngvalid,
+          * it has no effect on the limits applied to the libpng values.
+          */
+#if DIGITIZE
+          that->pm->limit += pow( 2.0/255, data.gamma);
+#else
+          that->pm->limit += pow( 1.0/255, data.gamma);
+#endif
+      }
+   }
+
+   else
+   {
+      /* With no gamma correction a large error comes from the truncation of the
+       * calculation in the 8 bit case, allow for that here.
+       */
+      if (that->this.bit_depth != 16 && !pm->assume_16_bit_calculations)
+         that->pm->limit += 4E-3;
+   }
+}
+
+static void
+image_transform_png_set_rgb_to_gray_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   int error_action = 1; /* no error, no defines in png.h */
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+      png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
+#  else
+      png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
+         data.green_to_set);
+#  endif
+
+#  ifdef PNG_READ_cHRM_SUPPORTED
+      if (that->pm->current_encoding != 0)
+      {
+         /* We have an encoding so a cHRM chunk may have been set; if so then
+          * check that the libpng APIs give the correct (X,Y,Z) values within
+          * some margin of error for the round trip through the chromaticity
+          * form.
+          */
+#        ifdef PNG_FLOATING_POINT_SUPPORTED
+#           define API_function png_get_cHRM_XYZ
+#           define API_form "FP"
+#           define API_type double
+#           define API_cvt(x) (x)
+#        else
+#           define API_function png_get_cHRM_XYZ_fixed
+#           define API_form "fixed"
+#           define API_type png_fixed_point
+#           define API_cvt(x) ((double)(x)/PNG_FP_1)
+#        endif
+
+         API_type rX, gX, bX;
+         API_type rY, gY, bY;
+         API_type rZ, gZ, bZ;
+
+         if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
+               & PNG_INFO_cHRM) != 0)
+         {
+            double maxe;
+            const char *el;
+            color_encoding e, o;
+
+            /* Expect libpng to return a normalized result, but the original
+             * color space encoding may not be normalized.
+             */
+            modifier_current_encoding(that->pm, &o);
+            normalize_color_encoding(&o);
+
+            /* Sanity check the pngvalid code - the coefficients should match
+             * the normalized Y values of the encoding unless they were
+             * overridden.
+             */
+            if (data.red_to_set == -1 && data.green_to_set == -1 &&
+               (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
+               fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
+               fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
+               png_error(pp, "internal pngvalid cHRM coefficient error");
+
+            /* Generate a colour space encoding. */
+            e.gamma = o.gamma; /* not used */
+            e.red.X = API_cvt(rX);
+            e.red.Y = API_cvt(rY);
+            e.red.Z = API_cvt(rZ);
+            e.green.X = API_cvt(gX);
+            e.green.Y = API_cvt(gY);
+            e.green.Z = API_cvt(gZ);
+            e.blue.X = API_cvt(bX);
+            e.blue.Y = API_cvt(bY);
+            e.blue.Z = API_cvt(bZ);
+
+            /* This should match the original one from the png_modifier, within
+             * the range permitted by the libpng fixed point representation.
+             */
+            maxe = 0;
+            el = "-"; /* Set to element name with error */
+
+#           define CHECK(col,x)\
+            {\
+               double err = fabs(o.col.x - e.col.x);\
+               if (err > maxe)\
+               {\
+                  maxe = err;\
+                  el = #col "(" #x ")";\
+               }\
+            }
+
+            CHECK(red,X)
+            CHECK(red,Y)
+            CHECK(red,Z)
+            CHECK(green,X)
+            CHECK(green,Y)
+            CHECK(green,Z)
+            CHECK(blue,X)
+            CHECK(blue,Y)
+            CHECK(blue,Z)
+
+            /* Here in both fixed and floating cases to check the values read
+             * from the cHRm chunk.  PNG uses fixed point in the cHRM chunk, so
+             * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
+             */
+            if (maxe >= 1E-5)
+            {
+               size_t pos = 0;
+               char buffer[256];
+
+               pos = safecat(buffer, sizeof buffer, pos, API_form);
+               pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
+               pos = safecat(buffer, sizeof buffer, pos, el);
+               pos = safecat(buffer, sizeof buffer, pos, " error: ");
+               pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
+               pos = safecat(buffer, sizeof buffer, pos, " ");
+               /* Print the color space without the gamma value: */
+               pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
+               pos = safecat(buffer, sizeof buffer, pos, " -> ");
+               pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
+
+               png_error(pp, buffer);
+            }
+         }
+      }
+#  endif /* READ_cHRM */
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_rgb_to_gray_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      double gray, err;
+
+#     if PNG_LIBPNG_VER < 10700
+         if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+            image_pixel_convert_PLTE(that);
+#     endif
+
+      /* Image now has RGB channels... */
+#  if DIGITIZE
+      {
+         png_modifier *pm = display->pm;
+         unsigned int sample_depth = that->sample_depth;
+         unsigned int calc_depth = (pm->assume_16_bit_calculations ? 16 :
+            sample_depth);
+         unsigned int gamma_depth =
+            (sample_depth == 16 ?
+               display->max_gamma_8 :
+               (pm->assume_16_bit_calculations ?
+                  display->max_gamma_8 :
+                  sample_depth));
+         int isgray;
+         double r, g, b;
+         double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
+
+         /* Do this using interval arithmetic, otherwise it is too difficult to
+          * handle the errors correctly.
+          *
+          * To handle the gamma correction work out the upper and lower bounds
+          * of the digitized value.  Assume rounding here - normally the values
+          * will be identical after this operation if there is only one
+          * transform, feel free to delete the png_error checks on this below in
+          * the future (this is just me trying to ensure it works!)
+          *
+          * Interval arithmetic is exact, but to implement it it must be
+          * possible to control the floating point implementation rounding mode.
+          * This cannot be done in ANSI-C, so instead I reduce the 'lo' values
+          * by DBL_EPSILON and increase the 'hi' values by the same.
+          */
+#        define DD(v,d,r) (digitize(v*(1-DBL_EPSILON), d, r) * (1-DBL_EPSILON))
+#        define DU(v,d,r) (digitize(v*(1+DBL_EPSILON), d, r) * (1+DBL_EPSILON))
+
+         r = rlo = rhi = that->redf;
+         rlo -= that->rede;
+         rlo = DD(rlo, calc_depth, 1/*round*/);
+         rhi += that->rede;
+         rhi = DU(rhi, calc_depth, 1/*round*/);
+
+         g = glo = ghi = that->greenf;
+         glo -= that->greene;
+         glo = DD(glo, calc_depth, 1/*round*/);
+         ghi += that->greene;
+         ghi = DU(ghi, calc_depth, 1/*round*/);
+
+         b = blo = bhi = that->bluef;
+         blo -= that->bluee;
+         blo = DD(blo, calc_depth, 1/*round*/);
+         bhi += that->bluee;
+         bhi = DU(bhi, calc_depth, 1/*round*/);
+
+         isgray = r==g && g==b;
+
+         if (data.gamma != 1)
+         {
+            const double power = 1/data.gamma;
+            const double abse = .5/(sample_depth == 16 ? 65535 : 255);
+
+            /* If a gamma calculation is done it is done using lookup tables of
+             * precision gamma_depth, so the already digitized value above may
+             * need to be further digitized here.
+             */
+            if (gamma_depth != calc_depth)
+            {
+               rlo = DD(rlo, gamma_depth, 0/*truncate*/);
+               rhi = DU(rhi, gamma_depth, 0/*truncate*/);
+               glo = DD(glo, gamma_depth, 0/*truncate*/);
+               ghi = DU(ghi, gamma_depth, 0/*truncate*/);
+               blo = DD(blo, gamma_depth, 0/*truncate*/);
+               bhi = DU(bhi, gamma_depth, 0/*truncate*/);
+            }
+
+            /* 'abse' is the error in the gamma table calculation itself. */
+            r = pow(r, power);
+            rlo = DD(pow(rlo, power)-abse, calc_depth, 1);
+            rhi = DU(pow(rhi, power)+abse, calc_depth, 1);
+
+            g = pow(g, power);
+            glo = DD(pow(glo, power)-abse, calc_depth, 1);
+            ghi = DU(pow(ghi, power)+abse, calc_depth, 1);
+
+            b = pow(b, power);
+            blo = DD(pow(blo, power)-abse, calc_depth, 1);
+            bhi = DU(pow(bhi, power)+abse, calc_depth, 1);
+         }
+
+         /* Now calculate the actual gray values.  Although the error in the
+          * coefficients depends on whether they were specified on the command
+          * line (in which case truncation to 15 bits happened) or not (rounding
+          * was used) the maximum error in an individual coefficient is always
+          * 2/32768, because even in the rounding case the requirement that
+          * coefficients add up to 32768 can cause a larger rounding error.
+          *
+          * The only time when rounding doesn't occur in 1.5.5 and later is when
+          * the non-gamma code path is used for less than 16 bit data.
+          */
+         gray = r * data.red_coefficient + g * data.green_coefficient +
+            b * data.blue_coefficient;
+
+         {
+            int do_round = data.gamma != 1 || calc_depth == 16;
+            const double ce = 2. / 32768;
+
+            graylo = DD(rlo * (data.red_coefficient-ce) +
+               glo * (data.green_coefficient-ce) +
+               blo * (data.blue_coefficient-ce), calc_depth, do_round);
+            if (graylo > gray) /* always accept the right answer */
+               graylo = gray;
+
+            grayhi = DU(rhi * (data.red_coefficient+ce) +
+               ghi * (data.green_coefficient+ce) +
+               bhi * (data.blue_coefficient+ce), calc_depth, do_round);
+            if (grayhi < gray)
+               grayhi = gray;
+         }
+
+         /* And invert the gamma. */
+         if (data.gamma != 1)
+         {
+            const double power = data.gamma;
+
+            /* And this happens yet again, shifting the values once more. */
+            if (gamma_depth != sample_depth)
+            {
+               rlo = DD(rlo, gamma_depth, 0/*truncate*/);
+               rhi = DU(rhi, gamma_depth, 0/*truncate*/);
+               glo = DD(glo, gamma_depth, 0/*truncate*/);
+               ghi = DU(ghi, gamma_depth, 0/*truncate*/);
+               blo = DD(blo, gamma_depth, 0/*truncate*/);
+               bhi = DU(bhi, gamma_depth, 0/*truncate*/);
+            }
+
+            gray = pow(gray, power);
+            graylo = DD(pow(graylo, power), sample_depth, 1);
+            grayhi = DU(pow(grayhi, power), sample_depth, 1);
+         }
+
+#        undef DD
+#        undef DU
+
+         /* Now the error can be calculated.
+          *
+          * If r==g==b because there is no overall gamma correction libpng
+          * currently preserves the original value.
+          */
+         if (isgray)
+            err = (that->rede + that->greene + that->bluee)/3;
+
+         else
+         {
+            err = fabs(grayhi-gray);
+
+            if (fabs(gray - graylo) > err)
+               err = fabs(graylo-gray);
+
+#if !RELEASE_BUILD
+            /* Check that this worked: */
+            if (err > pm->limit)
+            {
+               size_t pos = 0;
+               char buffer[128];
+
+               pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
+               pos = safecatd(buffer, sizeof buffer, pos, err, 6);
+               pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
+               pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
+               png_warning(pp, buffer);
+               pm->limit = err;
+            }
+#endif /* !RELEASE_BUILD */
+         }
+      }
+#  else  /* !DIGITIZE */
+      {
+         double r = that->redf;
+         double re = that->rede;
+         double g = that->greenf;
+         double ge = that->greene;
+         double b = that->bluef;
+         double be = that->bluee;
+
+#        if PNG_LIBPNG_VER < 10700
+            /* The true gray case involves no math in earlier versions (not
+             * true, there was some if gamma correction was happening too.)
+             */
+            if (r == g && r == b)
+            {
+               gray = r;
+               err = re;
+               if (err < ge) err = ge;
+               if (err < be) err = be;
+            }
+
+            else
+#        endif /* before 1.7 */
+         if (data.gamma == 1)
+         {
+            /* There is no need to do the conversions to and from linear space,
+             * so the calculation should be a lot more accurate.  There is a
+             * built in error in the coefficients because they only have 15 bits
+             * and are adjusted to make sure they add up to 32768.  This
+             * involves a integer calculation with truncation of the form:
+             *
+             *     ((int)(coefficient * 100000) * 32768)/100000
+             *
+             * This is done to the red and green coefficients (the ones
+             * provided to the API) then blue is calculated from them so the
+             * result adds up to 32768.  In the worst case this can result in
+             * a -1 error in red and green and a +2 error in blue.  Consequently
+             * the worst case in the calculation below is 2/32768 error.
+             *
+             * TODO: consider fixing this in libpng by rounding the calculation
+             * limiting the error to 1/32768.
+             *
+             * Handling this by adding 2/32768 here avoids needing to increase
+             * the global error limits to take this into account.)
+             */
+            gray = r * data.red_coefficient + g * data.green_coefficient +
+               b * data.blue_coefficient;
+            err = re * data.red_coefficient + ge * data.green_coefficient +
+               be * data.blue_coefficient + 2./32768 + gray * 5 * DBL_EPSILON;
+         }
+
+         else
+         {
+            /* The calculation happens in linear space, and this produces much
+             * wider errors in the encoded space.  These are handled here by
+             * factoring the errors in to the calculation.  There are two table
+             * lookups in the calculation and each introduces a quantization
+             * error defined by the table size.
+             */
+            png_modifier *pm = display->pm;
+            double in_qe = (that->sample_depth > 8 ? .5/65535 : .5/255);
+            double out_qe = (that->sample_depth > 8 ? .5/65535 :
+               (pm->assume_16_bit_calculations ? .5/(1<<display->max_gamma_8) :
+               .5/255));
+            double rhi, ghi, bhi, grayhi;
+            double g1 = 1/data.gamma;
+
+            rhi = r + re + in_qe; if (rhi > 1) rhi = 1;
+            r -= re + in_qe; if (r < 0) r = 0;
+            ghi = g + ge + in_qe; if (ghi > 1) ghi = 1;
+            g -= ge + in_qe; if (g < 0) g = 0;
+            bhi = b + be + in_qe; if (bhi > 1) bhi = 1;
+            b -= be + in_qe; if (b < 0) b = 0;
+
+            r = pow(r, g1)*(1-DBL_EPSILON); rhi = pow(rhi, g1)*(1+DBL_EPSILON);
+            g = pow(g, g1)*(1-DBL_EPSILON); ghi = pow(ghi, g1)*(1+DBL_EPSILON);
+            b = pow(b, g1)*(1-DBL_EPSILON); bhi = pow(bhi, g1)*(1+DBL_EPSILON);
+
+            /* Work out the lower and upper bounds for the gray value in the
+             * encoded space, then work out an average and error.  Remove the
+             * previously added input quantization error at this point.
+             */
+            gray = r * data.red_coefficient + g * data.green_coefficient +
+               b * data.blue_coefficient - 2./32768 - out_qe;
+            if (gray <= 0)
+               gray = 0;
+            else
+            {
+               gray *= (1 - 6 * DBL_EPSILON);
+               gray = pow(gray, data.gamma) * (1-DBL_EPSILON);
+            }
+
+            grayhi = rhi * data.red_coefficient + ghi * data.green_coefficient +
+               bhi * data.blue_coefficient + 2./32768 + out_qe;
+            grayhi *= (1 + 6 * DBL_EPSILON);
+            if (grayhi >= 1)
+               grayhi = 1;
+            else
+               grayhi = pow(grayhi, data.gamma) * (1+DBL_EPSILON);
+
+            err = (grayhi - gray) / 2;
+            gray = (grayhi + gray) / 2;
+
+            if (err <= in_qe)
+               err = gray * DBL_EPSILON;
+
+            else
+               err -= in_qe;
+
+#if !RELEASE_BUILD
+            /* Validate that the error is within limits (this has caused
+             * problems before, it's much easier to detect them here.)
+             */
+            if (err > pm->limit)
+            {
+               size_t pos = 0;
+               char buffer[128];
+
+               pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
+               pos = safecatd(buffer, sizeof buffer, pos, err, 6);
+               pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
+               pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
+               png_warning(pp, buffer);
+               pm->limit = err;
+            }
+#endif /* !RELEASE_BUILD */
+         }
+      }
+#  endif /* !DIGITIZE */
+
+      that->bluef = that->greenf = that->redf = gray;
+      that->bluee = that->greene = that->rede = err;
+
+      /* The sBIT is the minimum of the three colour channel sBITs. */
+      if (that->red_sBIT > that->green_sBIT)
+         that->red_sBIT = that->green_sBIT;
+      if (that->red_sBIT > that->blue_sBIT)
+         that->red_sBIT = that->blue_sBIT;
+      that->blue_sBIT = that->green_sBIT = that->red_sBIT;
+
+      /* And remove the colour bit in the type: */
+      if (that->colour_type == PNG_COLOR_TYPE_RGB)
+         that->colour_type = PNG_COLOR_TYPE_GRAY;
+      else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_rgb_to_gray_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
+}
+
+#undef data
+IT(rgb_to_gray);
+#undef PT
+#define PT ITSTRUCT(rgb_to_gray)
+#undef image_transform_ini
+#define image_transform_ini image_transform_default_ini
+#endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* png_set_background(png_structp, png_const_color_16p background_color,
+ *    int background_gamma_code, int need_expand, double background_gamma)
+ * png_set_background_fixed(png_structp, png_const_color_16p background_color,
+ *    int background_gamma_code, int need_expand,
+ *    png_fixed_point background_gamma)
+ *
+ * This ignores the gamma (at present.)
+*/
+#define data ITDATA(background)
+static image_pixel data;
+
+static void
+image_transform_png_set_background_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_byte colour_type, bit_depth;
+   png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
+   int expand;
+   png_color_16 back;
+
+   /* We need a background colour, because we don't know exactly what transforms
+    * have been set we have to supply the colour in the original file format and
+    * so we need to know what that is!  The background colour is stored in the
+    * transform_display.
+    */
+   R8(random_bytes);
+
+   /* Read the random value, for colour type 3 the background colour is actually
+    * expressed as a 24bit rgb, not an index.
+    */
+   colour_type = that->this.colour_type;
+   if (colour_type == 3)
+   {
+      colour_type = PNG_COLOR_TYPE_RGB;
+      bit_depth = 8;
+      expand = 0; /* passing in an RGB not a pixel index */
+   }
+
+   else
+   {
+      if (that->this.has_tRNS)
+         that->this.is_transparent = 1;
+
+      bit_depth = that->this.bit_depth;
+      expand = 1;
+   }
+
+   image_pixel_init(&data, random_bytes, colour_type,
+      bit_depth, 0/*x*/, 0/*unused: palette*/, NULL/*format*/);
+
+   /* Extract the background colour from this image_pixel, but make sure the
+    * unused fields of 'back' are garbage.
+    */
+   R8(back);
+
+   if (colour_type & PNG_COLOR_MASK_COLOR)
+   {
+      back.red = (png_uint_16)data.red;
+      back.green = (png_uint_16)data.green;
+      back.blue = (png_uint_16)data.blue;
+   }
+
+   else
+      back.gray = (png_uint_16)data.red;
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
+#else
+   png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
+#endif
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_background_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* Check for tRNS first: */
+   if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
+      image_pixel_add_alpha(that, &display->this, 1/*for background*/);
+
+   /* This is only necessary if the alpha value is less than 1. */
+   if (that->alphaf < 1)
+   {
+      /* Now we do the background calculation without any gamma correction. */
+      if (that->alphaf <= 0)
+      {
+         that->redf = data.redf;
+         that->greenf = data.greenf;
+         that->bluef = data.bluef;
+
+         that->rede = data.rede;
+         that->greene = data.greene;
+         that->bluee = data.bluee;
+
+         that->red_sBIT= data.red_sBIT;
+         that->green_sBIT= data.green_sBIT;
+         that->blue_sBIT= data.blue_sBIT;
+      }
+
+      else /* 0 < alpha < 1 */
+      {
+         double alf = 1 - that->alphaf;
+
+         that->redf = that->redf * that->alphaf + data.redf * alf;
+         that->rede = that->rede * that->alphaf + data.rede * alf +
+            DBL_EPSILON;
+         that->greenf = that->greenf * that->alphaf + data.greenf * alf;
+         that->greene = that->greene * that->alphaf + data.greene * alf +
+            DBL_EPSILON;
+         that->bluef = that->bluef * that->alphaf + data.bluef * alf;
+         that->bluee = that->bluee * that->alphaf + data.bluee * alf +
+            DBL_EPSILON;
+      }
+
+      /* Remove the alpha type and set the alpha (not in that order.) */
+      that->alphaf = 1;
+      that->alphae = 0;
+   }
+
+   if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_RGB;
+   else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_GRAY;
+   /* PNG_COLOR_TYPE_PALETTE is not changed */
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+#define image_transform_png_set_background_add image_transform_default_add
+
+#undef data
+IT(background);
+#undef PT
+#define PT ITSTRUCT(background)
+#endif /* PNG_READ_BACKGROUND_SUPPORTED */
+
+/* png_set_quantize(png_structp, png_colorp palette, int num_palette,
+ *    int maximum_colors, png_const_uint_16p histogram, int full_quantize)
+ *
+ * Very difficult to validate this!
+ */
+/*NOTE: TBD NYI */
+
+/* The data layout transforms are handled by swapping our own channel data,
+ * necessarily these need to happen at the end of the transform list because the
+ * semantic of the channels changes after these are executed.  Some of these,
+ * like set_shift and set_packing, can't be done at present because they change
+ * the layout of the data at the sub-sample level so sample() won't get the
+ * right answer.
+ */
+/* png_set_invert_alpha */
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+/* Invert the alpha channel
+ *
+ *  png_set_invert_alpha(png_structrp png_ptr)
+ */
+static void
+image_transform_png_set_invert_alpha_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_invert_alpha(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_invert_alpha_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type & 4)
+      that->alpha_inverted = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_invert_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* Only has an effect on pixels with alpha: */
+   return (colour_type & 4) != 0;
+}
+
+IT(invert_alpha);
+#undef PT
+#define PT ITSTRUCT(invert_alpha)
+
+#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
+
+/* png_set_bgr */
+#ifdef PNG_READ_BGR_SUPPORTED
+/* Swap R,G,B channels to order B,G,R.
+ *
+ *  png_set_bgr(png_structrp png_ptr)
+ *
+ * This only has an effect on RGB and RGBA pixels.
+ */
+static void
+image_transform_png_set_bgr_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_bgr(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_bgr_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_RGB ||
+       that->colour_type == PNG_COLOR_TYPE_RGBA)
+       that->swap_rgb = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_bgr_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return colour_type == PNG_COLOR_TYPE_RGB ||
+       colour_type == PNG_COLOR_TYPE_RGBA;
+}
+
+IT(bgr);
+#undef PT
+#define PT ITSTRUCT(bgr)
+
+#endif /* PNG_READ_BGR_SUPPORTED */
+
+/* png_set_swap_alpha */
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+/* Put the alpha channel first.
+ *
+ *  png_set_swap_alpha(png_structrp png_ptr)
+ *
+ * This only has an effect on GA and RGBA pixels.
+ */
+static void
+image_transform_png_set_swap_alpha_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_swap_alpha(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_swap_alpha_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_GA ||
+       that->colour_type == PNG_COLOR_TYPE_RGBA)
+      that->alpha_first = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_swap_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return colour_type == PNG_COLOR_TYPE_GA ||
+       colour_type == PNG_COLOR_TYPE_RGBA;
+}
+
+IT(swap_alpha);
+#undef PT
+#define PT ITSTRUCT(swap_alpha)
+
+#endif /* PNG_READ_SWAP_ALPHA_SUPPORTED */
+
+/* png_set_swap */
+#ifdef PNG_READ_SWAP_SUPPORTED
+/* Byte swap 16-bit components.
+ *
+ *  png_set_swap(png_structrp png_ptr)
+ */
+static void
+image_transform_png_set_swap_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_swap(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_swap_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth == 16)
+      that->swap16 = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_swap_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   return bit_depth == 16;
+}
+
+IT(swap);
+#undef PT
+#define PT ITSTRUCT(swap)
+
+#endif /* PNG_READ_SWAP_SUPPORTED */
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+/* Add a filler byte to 8-bit Gray or 24-bit RGB images.
+ *
+ *  png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags));
+ *
+ * Flags:
+ *
+ *  PNG_FILLER_BEFORE
+ *  PNG_FILLER_AFTER
+ */
+#define data ITDATA(filler)
+static struct
+{
+   png_uint_32 filler;
+   int         flags;
+} data;
+
+static void
+image_transform_png_set_filler_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   /* Need a random choice for 'before' and 'after' as well as for the
+    * filler.  The 'filler' value has all 32 bits set, but only bit_depth
+    * will be used.  At this point we don't know bit_depth.
+    */
+   data.filler = random_u32();
+   data.flags = random_choice();
+
+   png_set_filler(pp, data.filler, data.flags);
+
+   /* The standard display handling stuff also needs to know that
+    * there is a filler, so set that here.
+    */
+   that->this.filler = 1;
+
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_filler_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth >= 8 &&
+       (that->colour_type == PNG_COLOR_TYPE_RGB ||
+        that->colour_type == PNG_COLOR_TYPE_GRAY))
+   {
+      unsigned int max = (1U << that->bit_depth)-1;
+      that->alpha = data.filler & max;
+      that->alphaf = ((double)that->alpha) / max;
+      that->alphae = 0;
+
+      /* The filler has been stored in the alpha channel, we must record
+       * that this has been done for the checking later on, the color
+       * type is faked to have an alpha channel, but libpng won't report
+       * this; the app has to know the extra channel is there and this
+       * was recording in standard_display::filler above.
+       */
+      that->colour_type |= 4; /* alpha added */
+      that->alpha_first = data.flags == PNG_FILLER_BEFORE;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_filler_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   this->next = *that;
+   *that = this;
+
+   return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
+           colour_type == PNG_COLOR_TYPE_GRAY);
+}
+
+#undef data
+IT(filler);
+#undef PT
+#define PT ITSTRUCT(filler)
+
+/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
+/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
+#define data ITDATA(add_alpha)
+static struct
+{
+   png_uint_32 filler;
+   int         flags;
+} data;
+
+static void
+image_transform_png_set_add_alpha_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   /* Need a random choice for 'before' and 'after' as well as for the
+    * filler.  The 'filler' value has all 32 bits set, but only bit_depth
+    * will be used.  At this point we don't know bit_depth.
+    */
+   data.filler = random_u32();
+   data.flags = random_choice();
+
+   png_set_add_alpha(pp, data.filler, data.flags);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_add_alpha_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth >= 8 &&
+       (that->colour_type == PNG_COLOR_TYPE_RGB ||
+        that->colour_type == PNG_COLOR_TYPE_GRAY))
+   {
+      unsigned int max = (1U << that->bit_depth)-1;
+      that->alpha = data.filler & max;
+      that->alphaf = ((double)that->alpha) / max;
+      that->alphae = 0;
+
+      that->colour_type |= 4; /* alpha added */
+      that->alpha_first = data.flags == PNG_FILLER_BEFORE;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_add_alpha_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   this->next = *that;
+   *that = this;
+
+   return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
+           colour_type == PNG_COLOR_TYPE_GRAY);
+}
+
+#undef data
+IT(add_alpha);
+#undef PT
+#define PT ITSTRUCT(add_alpha)
+
+#endif /* PNG_READ_FILLER_SUPPORTED */
+
+/* png_set_packing */
+#ifdef PNG_READ_PACK_SUPPORTED
+/* Use 1 byte per pixel in 1, 2, or 4-bit depth files.
+ *
+ *  png_set_packing(png_structrp png_ptr)
+ *
+ * This should only affect grayscale and palette images with less than 8 bits
+ * per pixel.
+ */
+static void
+image_transform_png_set_packing_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_packing(pp);
+   that->unpacked = 1;
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_packing_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* The general expand case depends on what the colour type is,
+    * low bit-depth pixel values are unpacked into bytes without
+    * scaling, so sample_depth is not changed.
+    */
+   if (that->bit_depth < 8) /* grayscale or palette */
+      that->bit_depth = 8;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_packing_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   /* Nothing should happen unless the bit depth is less than 8: */
+   return bit_depth < 8;
+}
+
+IT(packing);
+#undef PT
+#define PT ITSTRUCT(packing)
+
+#endif /* PNG_READ_PACK_SUPPORTED */
+
+/* png_set_packswap */
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+/* Swap pixels packed into bytes; reverses the order on screen so that
+ * the high order bits correspond to the rightmost pixels.
+ *
+ *  png_set_packswap(png_structrp png_ptr)
+ */
+static void
+image_transform_png_set_packswap_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_packswap(pp);
+   that->this.littleendian = 1;
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_packswap_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->bit_depth < 8)
+      that->littleendian = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_packswap_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+
+   this->next = *that;
+   *that = this;
+
+   return bit_depth < 8;
+}
+
+IT(packswap);
+#undef PT
+#define PT ITSTRUCT(packswap)
+
+#endif /* PNG_READ_PACKSWAP_SUPPORTED */
+
+
+/* png_set_invert_mono */
+#ifdef PNG_READ_INVERT_MONO_SUPPORTED
+/* Invert the gray channel
+ *
+ *  png_set_invert_mono(png_structrp png_ptr)
+ */
+static void
+image_transform_png_set_invert_mono_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_invert_mono(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_invert_mono_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   if (that->colour_type & 4)
+      that->mono_inverted = 1;
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_invert_mono_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   /* Only has an effect on pixels with no colour: */
+   return (colour_type & 2) == 0;
+}
+
+IT(invert_mono);
+#undef PT
+#define PT ITSTRUCT(invert_mono)
+
+#endif /* PNG_READ_INVERT_MONO_SUPPORTED */
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+/* png_set_shift(png_structp, png_const_color_8p true_bits)
+ *
+ * The output pixels will be shifted by the given true_bits
+ * values.
+ */
+#define data ITDATA(shift)
+static png_color_8 data;
+
+static void
+image_transform_png_set_shift_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   /* Get a random set of shifts.  The shifts need to do something
+    * to test the transform, so they are limited to the bit depth
+    * of the input image.  Notice that in the following the 'gray'
+    * field is randomized independently.  This acts as a check that
+    * libpng does use the correct field.
+    */
+   unsigned int depth = that->this.bit_depth;
+
+   data.red = (png_byte)/*SAFE*/(random_mod(depth)+1);
+   data.green = (png_byte)/*SAFE*/(random_mod(depth)+1);
+   data.blue = (png_byte)/*SAFE*/(random_mod(depth)+1);
+   data.gray = (png_byte)/*SAFE*/(random_mod(depth)+1);
+   data.alpha = (png_byte)/*SAFE*/(random_mod(depth)+1);
+
+   png_set_shift(pp, &data);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_shift_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   /* Copy the correct values into the sBIT fields, libpng does not do
+    * anything to palette data:
+    */
+   if (that->colour_type != PNG_COLOR_TYPE_PALETTE)
+   {
+       that->sig_bits = 1;
+
+       /* The sBIT fields are reset to the values previously sent to
+        * png_set_shift according to the colour type.
+        * does.
+        */
+       if (that->colour_type & 2) /* RGB channels */
+       {
+          that->red_sBIT = data.red;
+          that->green_sBIT = data.green;
+          that->blue_sBIT = data.blue;
+       }
+
+       else /* One grey channel */
+          that->red_sBIT = that->green_sBIT = that->blue_sBIT = data.gray;
+
+       that->alpha_sBIT = data.alpha;
+   }
+
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_shift_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+
+   this->next = *that;
+   *that = this;
+
+   return colour_type != PNG_COLOR_TYPE_PALETTE;
+}
+
+IT(shift);
+#undef PT
+#define PT ITSTRUCT(shift)
+
+#endif /* PNG_READ_SHIFT_SUPPORTED */
+
+#ifdef THIS_IS_THE_PROFORMA
+static void
+image_transform_png_set_@_set(const image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_@(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_@_mod(const image_transform *this,
+    image_pixel *that, png_const_structp pp,
+    const transform_display *display)
+{
+   this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_@_add(image_transform *this,
+    const image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   this->next = *that;
+   *that = this;
+
+   return 1;
+}
+
+IT(@);
+#endif
+
+
+/* This may just be 'end' if all the transforms are disabled! */
+static image_transform *const image_transform_first = &PT;
+
+static void
+transform_enable(const char *name)
+{
+   /* Everything starts out enabled, so if we see an 'enable' disabled
+    * everything else the first time round.
+    */
+   static int all_disabled = 0;
+   int found_it = 0;
+   image_transform *list = image_transform_first;
+
+   while (list != &image_transform_end)
+   {
+      if (strcmp(list->name, name) == 0)
+      {
+         list->enable = 1;
+         found_it = 1;
+      }
+      else if (!all_disabled)
+         list->enable = 0;
+
+      list = list->list;
+   }
+
+   all_disabled = 1;
+
+   if (!found_it)
+   {
+      fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
+         name);
+      exit(99);
+   }
+}
+
+static void
+transform_disable(const char *name)
+{
+   image_transform *list = image_transform_first;
+
+   while (list != &image_transform_end)
+   {
+      if (strcmp(list->name, name) == 0)
+      {
+         list->enable = 0;
+         return;
+      }
+
+      list = list->list;
+   }
+
+   fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
+      name);
+   exit(99);
+}
+
+static void
+image_transform_reset_count(void)
+{
+   image_transform *next = image_transform_first;
+   int count = 0;
+
+   while (next != &image_transform_end)
+   {
+      next->local_use = 0;
+      next->next = 0;
+      next = next->list;
+      ++count;
+   }
+
+   /* This can only happen if we every have more than 32 transforms (excluding
+    * the end) in the list.
+    */
+   if (count > 32) abort();
+}
+
+static int
+image_transform_test_counter(png_uint_32 counter, unsigned int max)
+{
+   /* Test the list to see if there is any point continuing, given a current
+    * counter and a 'max' value.
+    */
+   image_transform *next = image_transform_first;
+
+   while (next != &image_transform_end)
+   {
+      /* For max 0 or 1 continue until the counter overflows: */
+      counter >>= 1;
+
+      /* Continue if any entry hasn't reacked the max. */
+      if (max > 1 && next->local_use < max)
+         return 1;
+      next = next->list;
+   }
+
+   return max <= 1 && counter == 0;
+}
+
+static png_uint_32
+image_transform_add(const image_transform **this, unsigned int max,
+   png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
+   png_byte colour_type, png_byte bit_depth)
+{
+   for (;;) /* until we manage to add something */
+   {
+      png_uint_32 mask;
+      image_transform *list;
+
+      /* Find the next counter value, if the counter is zero this is the start
+       * of the list.  This routine always returns the current counter (not the
+       * next) so it returns 0 at the end and expects 0 at the beginning.
+       */
+      if (counter == 0) /* first time */
+      {
+         image_transform_reset_count();
+         if (max <= 1)
+            counter = 1;
+         else
+            counter = random_32();
+      }
+      else /* advance the counter */
+      {
+         switch (max)
+         {
+            case 0:  ++counter; break;
+            case 1:  counter <<= 1; break;
+            default: counter = random_32(); break;
+         }
+      }
+
+      /* Now add all these items, if possible */
+      *this = &image_transform_end;
+      list = image_transform_first;
+      mask = 1;
+
+      /* Go through the whole list adding anything that the counter selects: */
+      while (list != &image_transform_end)
+      {
+         if ((counter & mask) != 0 && list->enable &&
+             (max == 0 || list->local_use < max))
+         {
+            /* Candidate to add: */
+            if (list->add(list, this, colour_type, bit_depth) || max == 0)
+            {
+               /* Added, so add to the name too. */
+               *pos = safecat(name, sizeof_name, *pos, " +");
+               *pos = safecat(name, sizeof_name, *pos, list->name);
+            }
+
+            else
+            {
+               /* Not useful and max>0, so remove it from *this: */
+               *this = list->next;
+               list->next = 0;
+
+               /* And, since we know it isn't useful, stop it being added again
+                * in this run:
+                */
+               list->local_use = max;
+            }
+         }
+
+         mask <<= 1;
+         list = list->list;
+      }
+
+      /* Now if anything was added we have something to do. */
+      if (*this != &image_transform_end)
+         return counter;
+
+      /* Nothing added, but was there anything in there to add? */
+      if (!image_transform_test_counter(counter, max))
+         return 0;
+   }
+}
+
+static void
+perform_transform_test(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   while (next_format(&colour_type, &bit_depth, &palette_number, pm->test_lbg,
+            pm->test_tRNS))
+   {
+      png_uint_32 counter = 0;
+      size_t base_pos;
+      char name[64];
+
+      base_pos = safecat(name, sizeof name, 0, "transform:");
+
+      for (;;)
+      {
+         size_t pos = base_pos;
+         const image_transform *list = 0;
+
+         /* 'max' is currently hardwired to '1'; this should be settable on the
+          * command line.
+          */
+         counter = image_transform_add(&list, 1/*max*/, counter,
+            name, sizeof name, &pos, colour_type, bit_depth);
+
+         if (counter == 0)
+            break;
+
+         /* The command line can change this to checking interlaced images. */
+         do
+         {
+            pm->repeat = 0;
+            transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
+               pm->interlace_type, 0, 0, 0), list, name);
+
+            if (fail(pm))
+               return;
+         }
+         while (pm->repeat);
+      }
+   }
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+/********************************* GAMMA TESTS ********************************/
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Reader callbacks and implementations, where they differ from the standard
+ * ones.
+ */
+typedef struct gamma_display
+{
+   standard_display this;
+
+   /* Parameters */
+   png_modifier*    pm;
+   double           file_gamma;
+   double           screen_gamma;
+   double           background_gamma;
+   png_byte         sbit;
+   int              threshold_test;
+   int              use_input_precision;
+   int              scale16;
+   int              expand16;
+   int              do_background;
+   png_color_16     background_color;
+
+   /* Local variables */
+   double       maxerrout;
+   double       maxerrpc;
+   double       maxerrabs;
+} gamma_display;
+
+#define ALPHA_MODE_OFFSET 4
+
+static void
+gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
+    double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
+    int use_input_precision, int scale16, int expand16,
+    int do_background, const png_color_16 *pointer_to_the_background_color,
+    double background_gamma)
+{
+   /* Standard fields */
+   standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
+      pm->use_update_info);
+
+   /* Parameter fields */
+   dp->pm = pm;
+   dp->file_gamma = file_gamma;
+   dp->screen_gamma = screen_gamma;
+   dp->background_gamma = background_gamma;
+   dp->sbit = sbit;
+   dp->threshold_test = threshold_test;
+   dp->use_input_precision = use_input_precision;
+   dp->scale16 = scale16;
+   dp->expand16 = expand16;
+   dp->do_background = do_background;
+   if (do_background && pointer_to_the_background_color != 0)
+      dp->background_color = *pointer_to_the_background_color;
+   else
+      memset(&dp->background_color, 0, sizeof dp->background_color);
+
+   /* Local variable fields */
+   dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
+}
+
+static void
+gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
+{
+   /* Reuse the standard stuff as appropriate. */
+   standard_info_part1(&dp->this, pp, pi);
+
+   /* If requested strip 16 to 8 bits - this is handled automagically below
+    * because the output bit depth is read from the library.  Note that there
+    * are interactions with sBIT but, internally, libpng makes sbit at most
+    * PNG_MAX_GAMMA_8 prior to 1.7 when doing the following.
+    */
+   if (dp->scale16)
+#     ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+         png_set_scale_16(pp);
+#     else
+         /* The following works both in 1.5.4 and earlier versions: */
+#        ifdef PNG_READ_16_TO_8_SUPPORTED
+            png_set_strip_16(pp);
+#        else
+            png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
+#        endif
+#     endif
+
+   if (dp->expand16)
+#     ifdef PNG_READ_EXPAND_16_SUPPORTED
+         png_set_expand_16(pp);
+#     else
+         png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
+#     endif
+
+   if (dp->do_background >= ALPHA_MODE_OFFSET)
+   {
+#     ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      {
+         /* This tests the alpha mode handling, if supported. */
+         int mode = dp->do_background - ALPHA_MODE_OFFSET;
+
+         /* The gamma value is the output gamma, and is in the standard,
+          * non-inverted, representation.  It provides a default for the PNG file
+          * gamma, but since the file has a gAMA chunk this does not matter.
+          */
+         const double sg = dp->screen_gamma;
+#        ifndef PNG_FLOATING_POINT_SUPPORTED
+            png_fixed_point g = fix(sg);
+#        endif
+
+#        ifdef PNG_FLOATING_POINT_SUPPORTED
+            png_set_alpha_mode(pp, mode, sg);
+#        else
+            png_set_alpha_mode_fixed(pp, mode, g);
+#        endif
+
+         /* However, for the standard Porter-Duff algorithm the output defaults
+          * to be linear, so if the test requires non-linear output it must be
+          * corrected here.
+          */
+         if (mode == PNG_ALPHA_STANDARD && sg != 1)
+         {
+#           ifdef PNG_FLOATING_POINT_SUPPORTED
+               png_set_gamma(pp, sg, dp->file_gamma);
+#           else
+               png_fixed_point f = fix(dp->file_gamma);
+               png_set_gamma_fixed(pp, g, f);
+#           endif
+         }
+      }
+#     else
+         png_error(pp, "alpha mode handling not supported");
+#     endif
+   }
+
+   else
+   {
+      /* Set up gamma processing. */
+#     ifdef PNG_FLOATING_POINT_SUPPORTED
+         png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
+#     else
+      {
+         png_fixed_point s = fix(dp->screen_gamma);
+         png_fixed_point f = fix(dp->file_gamma);
+         png_set_gamma_fixed(pp, s, f);
+      }
+#     endif
+
+      if (dp->do_background)
+      {
+#     ifdef PNG_READ_BACKGROUND_SUPPORTED
+         /* NOTE: this assumes the caller provided the correct background gamma!
+          */
+         const double bg = dp->background_gamma;
+#        ifndef PNG_FLOATING_POINT_SUPPORTED
+            png_fixed_point g = fix(bg);
+#        endif
+
+#        ifdef PNG_FLOATING_POINT_SUPPORTED
+            png_set_background(pp, &dp->background_color, dp->do_background,
+               0/*need_expand*/, bg);
+#        else
+            png_set_background_fixed(pp, &dp->background_color,
+               dp->do_background, 0/*need_expand*/, g);
+#        endif
+#     else
+         png_error(pp, "png_set_background not supported");
+#     endif
+      }
+   }
+
+   {
+      int i = dp->this.use_update_info;
+      /* Always do one call, even if use_update_info is 0. */
+      do
+         png_read_update_info(pp, pi);
+      while (--i > 0);
+   }
+
+   /* Now we may get a different cbRow: */
+   standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
+}
+
+static void PNGCBAPI
+gamma_info(png_structp pp, png_infop pi)
+{
+   gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
+      pi);
+}
+
+/* Validate a single component value - the routine gets the input and output
+ * sample values as unscaled PNG component values along with a cache of all the
+ * information required to validate the values.
+ */
+typedef struct validate_info
+{
+   png_const_structp  pp;
+   gamma_display *dp;
+   png_byte sbit;
+   int use_input_precision;
+   int do_background;
+   int scale16;
+   unsigned int sbit_max;
+   unsigned int isbit_shift;
+   unsigned int outmax;
+
+   double gamma_correction; /* Overall correction required. */
+   double file_inverse;     /* Inverse of file gamma. */
+   double screen_gamma;
+   double screen_inverse;   /* Inverse of screen gamma. */
+
+   double background_red;   /* Linear background value, red or gray. */
+   double background_green;
+   double background_blue;
+
+   double maxabs;
+   double maxpc;
+   double maxcalc;
+   double maxout;
+   double maxout_total;     /* Total including quantization error */
+   double outlog;
+   int    outquant;
+}
+validate_info;
+
+static void
+init_validate_info(validate_info *vi, gamma_display *dp, png_const_structp pp,
+    int in_depth, int out_depth)
+{
+   unsigned int outmax = (1U<<out_depth)-1;
+
+   vi->pp = pp;
+   vi->dp = dp;
+
+   if (dp->sbit > 0 && dp->sbit < in_depth)
+   {
+      vi->sbit = dp->sbit;
+      vi->isbit_shift = in_depth - dp->sbit;
+   }
+
+   else
+   {
+      vi->sbit = (png_byte)in_depth;
+      vi->isbit_shift = 0;
+   }
+
+   vi->sbit_max = (1U << vi->sbit)-1;
+
+   /* This mimics the libpng threshold test, '0' is used to prevent gamma
+    * correction in the validation test.
+    */
+   vi->screen_gamma = dp->screen_gamma;
+   if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
+      vi->screen_gamma = vi->screen_inverse = 0;
+   else
+      vi->screen_inverse = 1/vi->screen_gamma;
+
+   vi->use_input_precision = dp->use_input_precision;
+   vi->outmax = outmax;
+   vi->maxabs = abserr(dp->pm, in_depth, out_depth);
+   vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
+   vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
+   vi->maxout = outerr(dp->pm, in_depth, out_depth);
+   vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
+   vi->maxout_total = vi->maxout + vi->outquant * .5;
+   vi->outlog = outlog(dp->pm, in_depth, out_depth);
+
+   if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
+      (dp->this.colour_type == 3 && dp->this.is_transparent) ||
+      ((dp->this.colour_type == 0 || dp->this.colour_type == 2) &&
+       dp->this.has_tRNS))
+   {
+      vi->do_background = dp->do_background;
+
+      if (vi->do_background != 0)
+      {
+         const double bg_inverse = 1/dp->background_gamma;
+         double r, g, b;
+
+         /* Caller must at least put the gray value into the red channel */
+         r = dp->background_color.red; r /= outmax;
+         g = dp->background_color.green; g /= outmax;
+         b = dp->background_color.blue; b /= outmax;
+
+#     if 0
+         /* libpng doesn't do this optimization, if we do pngvalid will fail.
+          */
+         if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
+#     endif
+         {
+            r = pow(r, bg_inverse);
+            g = pow(g, bg_inverse);
+            b = pow(b, bg_inverse);
+         }
+
+         vi->background_red = r;
+         vi->background_green = g;
+         vi->background_blue = b;
+      }
+   }
+   else /* Do not expect any background processing */
+      vi->do_background = 0;
+
+   if (vi->do_background == 0)
+      vi->background_red = vi->background_green = vi->background_blue = 0;
+
+   vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
+   if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
+      vi->gamma_correction = 0;
+
+   vi->file_inverse = 1/dp->file_gamma;
+   if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
+      vi->file_inverse = 0;
+
+   vi->scale16 = dp->scale16;
+}
+
+/* This function handles composition of a single non-alpha component.  The
+ * argument is the input sample value, in the range 0..1, and the alpha value.
+ * The result is the composed, linear, input sample.  If alpha is less than zero
+ * this is the alpha component and the function should not be called!
+ */
+static double
+gamma_component_compose(int do_background, double input_sample, double alpha,
+   double background, int *compose)
+{
+   switch (do_background)
+   {
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+      case PNG_BACKGROUND_GAMMA_SCREEN:
+      case PNG_BACKGROUND_GAMMA_FILE:
+      case PNG_BACKGROUND_GAMMA_UNIQUE:
+         /* Standard PNG background processing. */
+         if (alpha < 1)
+         {
+            if (alpha > 0)
+            {
+               input_sample = input_sample * alpha + background * (1-alpha);
+               if (compose != NULL)
+                  *compose = 1;
+            }
+
+            else
+               input_sample = background;
+         }
+         break;
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+         /* The components are premultiplied in either case and the output is
+          * gamma encoded (to get standard Porter-Duff we expect the output
+          * gamma to be set to 1.0!)
+          */
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+         /* The optimization is that the partial-alpha entries are linear
+          * while the opaque pixels are gamma encoded, but this only affects the
+          * output encoding.
+          */
+         if (alpha < 1)
+         {
+            if (alpha > 0)
+            {
+               input_sample *= alpha;
+               if (compose != NULL)
+                  *compose = 1;
+            }
+
+            else
+               input_sample = 0;
+         }
+         break;
+#endif
+
+      default:
+         /* Standard cases where no compositing is done (so the component
+          * value is already correct.)
+          */
+         UNUSED(alpha)
+         UNUSED(background)
+         UNUSED(compose)
+         break;
+   }
+
+   return input_sample;
+}
+
+/* This API returns the encoded *input* component, in the range 0..1 */
+static double
+gamma_component_validate(const char *name, const validate_info *vi,
+    unsigned int id, unsigned int od,
+    const double alpha /* <0 for the alpha channel itself */,
+    const double background /* component background value */)
+{
+   unsigned int isbit = id >> vi->isbit_shift;
+   unsigned int sbit_max = vi->sbit_max;
+   unsigned int outmax = vi->outmax;
+   int do_background = vi->do_background;
+
+   double i;
+
+   /* First check on the 'perfect' result obtained from the digitized input
+    * value, id, and compare this against the actual digitized result, 'od'.
+    * 'i' is the input result in the range 0..1:
+    */
+   i = isbit; i /= sbit_max;
+
+   /* Check for the fast route: if we don't do any background composition or if
+    * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
+    * just use the gamma_correction field to correct to the final output gamma.
+    */
+   if (alpha == 1 /* opaque pixel component */ || !do_background
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
+#endif
+      || (alpha < 0 /* alpha channel */
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
+#endif
+      ))
+   {
+      /* Then get the gamma corrected version of 'i' and compare to 'od', any
+       * error less than .5 is insignificant - just quantization of the output
+       * value to the nearest digital value (nevertheless the error is still
+       * recorded - it's interesting ;-)
+       */
+      double encoded_sample = i;
+      double encoded_error;
+
+      /* alpha less than 0 indicates the alpha channel, which is always linear
+       */
+      if (alpha >= 0 && vi->gamma_correction > 0)
+         encoded_sample = pow(encoded_sample, vi->gamma_correction);
+      encoded_sample *= outmax;
+
+      encoded_error = fabs(od-encoded_sample);
+
+      if (encoded_error > vi->dp->maxerrout)
+         vi->dp->maxerrout = encoded_error;
+
+      if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
+         return i;
+   }
+
+   /* The slow route - attempt to do linear calculations. */
+   /* There may be an error, or background processing is required, so calculate
+    * the actual sample values - unencoded light intensity values.  Note that in
+    * practice these are not completely unencoded because they include a
+    * 'viewing correction' to decrease or (normally) increase the perceptual
+    * contrast of the image.  There's nothing we can do about this - we don't
+    * know what it is - so assume the unencoded value is perceptually linear.
+    */
+   {
+      double input_sample = i; /* In range 0..1 */
+      double output, error, encoded_sample, encoded_error;
+      double es_lo, es_hi;
+      int compose = 0;           /* Set to one if composition done */
+      int output_is_encoded;     /* Set if encoded to screen gamma */
+      int log_max_error = 1;     /* Check maximum error values */
+      png_const_charp pass = 0;  /* Reason test passes (or 0 for fail) */
+
+      /* Convert to linear light (with the above caveat.)  The alpha channel is
+       * already linear.
+       */
+      if (alpha >= 0)
+      {
+         int tcompose;
+
+         if (vi->file_inverse > 0)
+            input_sample = pow(input_sample, vi->file_inverse);
+
+         /* Handle the compose processing: */
+         tcompose = 0;
+         input_sample = gamma_component_compose(do_background, input_sample,
+            alpha, background, &tcompose);
+
+         if (tcompose)
+            compose = 1;
+      }
+
+      /* And similarly for the output value, but we need to check the background
+       * handling to linearize it correctly.
+       */
+      output = od;
+      output /= outmax;
+
+      output_is_encoded = vi->screen_gamma > 0;
+
+      if (alpha < 0) /* The alpha channel */
+      {
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+         if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
+#endif
+         {
+            /* In all other cases the output alpha channel is linear already,
+             * don't log errors here, they are much larger in linear data.
+             */
+            output_is_encoded = 0;
+            log_max_error = 0;
+         }
+      }
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      else /* A component */
+      {
+         if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
+            alpha < 1) /* the optimized case - linear output */
+         {
+            if (alpha > 0) log_max_error = 0;
+            output_is_encoded = 0;
+         }
+      }
+#endif
+
+      if (output_is_encoded)
+         output = pow(output, vi->screen_gamma);
+
+      /* Calculate (or recalculate) the encoded_sample value and repeat the
+       * check above (unnecessary if we took the fast route, but harmless.)
+       */
+      encoded_sample = input_sample;
+      if (output_is_encoded)
+         encoded_sample = pow(encoded_sample, vi->screen_inverse);
+      encoded_sample *= outmax;
+
+      encoded_error = fabs(od-encoded_sample);
+
+      /* Don't log errors in the alpha channel, or the 'optimized' case,
+       * neither are significant to the overall perception.
+       */
+      if (log_max_error && encoded_error > vi->dp->maxerrout)
+         vi->dp->maxerrout = encoded_error;
+
+      if (encoded_error < vi->maxout_total)
+      {
+         if (encoded_error < vi->outlog)
+            return i;
+
+         /* Test passed but error is bigger than the log limit, record why the
+          * test passed:
+          */
+         pass = "less than maxout:\n";
+      }
+
+      /* i: the original input value in the range 0..1
+       *
+       * pngvalid calculations:
+       *  input_sample: linear result; i linearized and composed, range 0..1
+       *  encoded_sample: encoded result; input_sample scaled to output bit depth
+       *
+       * libpng calculations:
+       *  output: linear result; od scaled to 0..1 and linearized
+       *  od: encoded result from libpng
+       */
+
+      /* Now we have the numbers for real errors, both absolute values as as a
+       * percentage of the correct value (output):
+       */
+      error = fabs(input_sample-output);
+
+      if (log_max_error && error > vi->dp->maxerrabs)
+         vi->dp->maxerrabs = error;
+
+      /* The following is an attempt to ignore the tendency of quantization to
+       * dominate the percentage errors for lower result values:
+       */
+      if (log_max_error && input_sample > .5)
+      {
+         double percentage_error = error/input_sample;
+         if (percentage_error > vi->dp->maxerrpc)
+            vi->dp->maxerrpc = percentage_error;
+      }
+
+      /* Now calculate the digitization limits for 'encoded_sample' using the
+       * 'max' values.  Note that maxout is in the encoded space but maxpc and
+       * maxabs are in linear light space.
+       *
+       * First find the maximum error in linear light space, range 0..1:
+       */
+      {
+         double tmp = input_sample * vi->maxpc;
+         if (tmp < vi->maxabs) tmp = vi->maxabs;
+         /* If 'compose' is true the composition was done in linear space using
+          * integer arithmetic.  This introduces an extra error of +/- 0.5 (at
+          * least) in the integer space used.  'maxcalc' records this, taking
+          * into account the possibility that even for 16 bit output 8 bit space
+          * may have been used.
+          */
+         if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
+
+         /* The 'maxout' value refers to the encoded result, to compare with
+          * this encode input_sample adjusted by the maximum error (tmp) above.
+          */
+         es_lo = encoded_sample - vi->maxout;
+
+         if (es_lo > 0 && input_sample-tmp > 0)
+         {
+            double low_value = input_sample-tmp;
+            if (output_is_encoded)
+               low_value = pow(low_value, vi->screen_inverse);
+            low_value *= outmax;
+            if (low_value < es_lo) es_lo = low_value;
+
+            /* Quantize this appropriately: */
+            es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
+         }
+
+         else
+            es_lo = 0;
+
+         es_hi = encoded_sample + vi->maxout;
+
+         if (es_hi < outmax && input_sample+tmp < 1)
+         {
+            double high_value = input_sample+tmp;
+            if (output_is_encoded)
+               high_value = pow(high_value, vi->screen_inverse);
+            high_value *= outmax;
+            if (high_value > es_hi) es_hi = high_value;
+
+            es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
+         }
+
+         else
+            es_hi = outmax;
+      }
+
+      /* The primary test is that the final encoded value returned by the
+       * library should be between the two limits (inclusive) that were
+       * calculated above.
+       */
+      if (od >= es_lo && od <= es_hi)
+      {
+         /* The value passes, but we may need to log the information anyway. */
+         if (encoded_error < vi->outlog)
+            return i;
+
+         if (pass == 0)
+            pass = "within digitization limits:\n";
+      }
+
+      {
+         /* There has been an error in processing, or we need to log this
+          * value.
+          */
+         double is_lo, is_hi;
+
+         /* pass is set at this point if either of the tests above would have
+          * passed.  Don't do these additional tests here - just log the
+          * original [es_lo..es_hi] values.
+          */
+         if (pass == 0 && vi->use_input_precision && vi->dp->sbit)
+         {
+            /* Ok, something is wrong - this actually happens in current libpng
+             * 16-to-8 processing.  Assume that the input value (id, adjusted
+             * for sbit) can be anywhere between value-.5 and value+.5 - quite a
+             * large range if sbit is low.
+             *
+             * NOTE: at present because the libpng gamma table stuff has been
+             * changed to use a rounding algorithm to correct errors in 8-bit
+             * calculations the precise sbit calculation (a shift) has been
+             * lost.  This can result in up to a +/-1 error in the presence of
+             * an sbit less than the bit depth.
+             */
+#           if PNG_LIBPNG_VER < 10700
+#              define SBIT_ERROR .5
+#           else
+#              define SBIT_ERROR 1.
+#           endif
+            double tmp = (isbit - SBIT_ERROR)/sbit_max;
+
+            if (tmp <= 0)
+               tmp = 0;
+
+            else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
+               tmp = pow(tmp, vi->file_inverse);
+
+            tmp = gamma_component_compose(do_background, tmp, alpha, background,
+               NULL);
+
+            if (output_is_encoded && tmp > 0 && tmp < 1)
+               tmp = pow(tmp, vi->screen_inverse);
+
+            is_lo = ceil(outmax * tmp - vi->maxout_total);
+
+            if (is_lo < 0)
+               is_lo = 0;
+
+            tmp = (isbit + SBIT_ERROR)/sbit_max;
+
+            if (tmp >= 1)
+               tmp = 1;
+
+            else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
+               tmp = pow(tmp, vi->file_inverse);
+
+            tmp = gamma_component_compose(do_background, tmp, alpha, background,
+               NULL);
+
+            if (output_is_encoded && tmp > 0 && tmp < 1)
+               tmp = pow(tmp, vi->screen_inverse);
+
+            is_hi = floor(outmax * tmp + vi->maxout_total);
+
+            if (is_hi > outmax)
+               is_hi = outmax;
+
+            if (!(od < is_lo || od > is_hi))
+            {
+               if (encoded_error < vi->outlog)
+                  return i;
+
+               pass = "within input precision limits:\n";
+            }
+
+            /* One last chance.  If this is an alpha channel and the 16to8
+             * option has been used and 'inaccurate' scaling is used then the
+             * bit reduction is obtained by simply using the top 8 bits of the
+             * value.
+             *
+             * This is only done for older libpng versions when the 'inaccurate'
+             * (chop) method of scaling was used.
+             */
+#           ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+#              if PNG_LIBPNG_VER < 10504
+                  /* This may be required for other components in the future,
+                   * but at present the presence of gamma correction effectively
+                   * prevents the errors in the component scaling (I don't quite
+                   * understand why, but since it's better this way I care not
+                   * to ask, JB 20110419.)
+                   */
+                  if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
+                     vi->sbit + vi->isbit_shift == 16)
+                  {
+                     tmp = ((id >> 8) - .5)/255;
+
+                     if (tmp > 0)
+                     {
+                        is_lo = ceil(outmax * tmp - vi->maxout_total);
+                        if (is_lo < 0) is_lo = 0;
+                     }
+
+                     else
+                        is_lo = 0;
+
+                     tmp = ((id >> 8) + .5)/255;
+
+                     if (tmp < 1)
+                     {
+                        is_hi = floor(outmax * tmp + vi->maxout_total);
+                        if (is_hi > outmax) is_hi = outmax;
+                     }
+
+                     else
+                        is_hi = outmax;
+
+                     if (!(od < is_lo || od > is_hi))
+                     {
+                        if (encoded_error < vi->outlog)
+                           return i;
+
+                        pass = "within 8 bit limits:\n";
+                     }
+                  }
+#              endif
+#           endif
+         }
+         else /* !use_input_precision */
+            is_lo = es_lo, is_hi = es_hi;
+
+         /* Attempt to output a meaningful error/warning message: the message
+          * output depends on the background/composite operation being performed
+          * because this changes what parameters were actually used above.
+          */
+         {
+            size_t pos = 0;
+            /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
+             * places.  Just use outmax to work out which.
+             */
+            int precision = (outmax >= 1000 ? 6 : 3);
+            int use_input=1, use_background=0, do_compose=0;
+            char msg[256];
+
+            if (pass != 0)
+               pos = safecat(msg, sizeof msg, pos, "\n\t");
+
+            /* Set up the various flags, the output_is_encoded flag above
+             * is also used below.  do_compose is just a double check.
+             */
+            switch (do_background)
+            {
+#           ifdef PNG_READ_BACKGROUND_SUPPORTED
+               case PNG_BACKGROUND_GAMMA_SCREEN:
+               case PNG_BACKGROUND_GAMMA_FILE:
+               case PNG_BACKGROUND_GAMMA_UNIQUE:
+                  use_background = (alpha >= 0 && alpha < 1);
+#           endif
+#           ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+               /* FALLTHROUGH */
+               case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+               case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+               case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+#           endif /* ALPHA_MODE_SUPPORTED */
+#           if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
+               (defined PNG_READ_ALPHA_MODE_SUPPORTED)
+               do_compose = (alpha > 0 && alpha < 1);
+               use_input = (alpha != 0);
+               break;
+#           endif
+
+            default:
+               break;
+            }
+
+            /* Check the 'compose' flag */
+            if (compose != do_compose)
+               png_error(vi->pp, "internal error (compose)");
+
+            /* 'name' is the component name */
+            pos = safecat(msg, sizeof msg, pos, name);
+            pos = safecat(msg, sizeof msg, pos, "(");
+            pos = safecatn(msg, sizeof msg, pos, id);
+            if (use_input || pass != 0/*logging*/)
+            {
+               if (isbit != id)
+               {
+                  /* sBIT has reduced the precision of the input: */
+                  pos = safecat(msg, sizeof msg, pos, ", sbit(");
+                  pos = safecatn(msg, sizeof msg, pos, vi->sbit);
+                  pos = safecat(msg, sizeof msg, pos, "): ");
+                  pos = safecatn(msg, sizeof msg, pos, isbit);
+               }
+               pos = safecat(msg, sizeof msg, pos, "/");
+               /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
+               pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
+            }
+            pos = safecat(msg, sizeof msg, pos, ")");
+
+            /* A component may have been multiplied (in linear space) by the
+             * alpha value, 'compose' says whether this is relevant.
+             */
+            if (compose || pass != 0)
+            {
+               /* If any form of composition is being done report our
+                * calculated linear value here (the code above doesn't record
+                * the input value before composition is performed, so what
+                * gets reported is the value after composition.)
+                */
+               if (use_input || pass != 0)
+               {
+                  if (vi->file_inverse > 0)
+                  {
+                     pos = safecat(msg, sizeof msg, pos, "^");
+                     pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
+                  }
+
+                  else
+                     pos = safecat(msg, sizeof msg, pos, "[linear]");
+
+                  pos = safecat(msg, sizeof msg, pos, "*(alpha)");
+                  pos = safecatd(msg, sizeof msg, pos, alpha, precision);
+               }
+
+               /* Now record the *linear* background value if it was used
+                * (this function is not passed the original, non-linear,
+                * value but it is contained in the test name.)
+                */
+               if (use_background)
+               {
+                  pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
+                  pos = safecat(msg, sizeof msg, pos, "(background)");
+                  pos = safecatd(msg, sizeof msg, pos, background, precision);
+                  pos = safecat(msg, sizeof msg, pos, "*");
+                  pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
+               }
+            }
+
+            /* Report the calculated value (input_sample) and the linearized
+             * libpng value (output) unless this is just a component gamma
+             * correction.
+             */
+            if (compose || alpha < 0 || pass != 0)
+            {
+               pos = safecat(msg, sizeof msg, pos,
+                  pass != 0 ? " =\n\t" : " = ");
+               pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
+               pos = safecat(msg, sizeof msg, pos, " (libpng: ");
+               pos = safecatd(msg, sizeof msg, pos, output, precision);
+               pos = safecat(msg, sizeof msg, pos, ")");
+
+               /* Finally report the output gamma encoding, if any. */
+               if (output_is_encoded)
+               {
+                  pos = safecat(msg, sizeof msg, pos, " ^");
+                  pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
+                  pos = safecat(msg, sizeof msg, pos, "(to screen) =");
+               }
+
+               else
+                  pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
+            }
+
+            if ((!compose && alpha >= 0) || pass != 0)
+            {
+               if (pass != 0) /* logging */
+                  pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
+
+               /* This is the non-composition case, the internal linear
+                * values are irrelevant (though the log below will reveal
+                * them.)  Output a much shorter warning/error message and report
+                * the overall gamma correction.
+                */
+               if (vi->gamma_correction > 0)
+               {
+                  pos = safecat(msg, sizeof msg, pos, " ^");
+                  pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
+                  pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
+               }
+
+               else
+                  pos = safecat(msg, sizeof msg, pos,
+                     " [no gamma correction] =");
+
+               if (pass != 0)
+                  pos = safecat(msg, sizeof msg, pos, "]");
+            }
+
+            /* This is our calculated encoded_sample which should (but does
+             * not) match od:
+             */
+            pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
+            pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
+            pos = safecat(msg, sizeof msg, pos, " < ");
+            pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
+            pos = safecat(msg, sizeof msg, pos, " (libpng: ");
+            pos = safecatn(msg, sizeof msg, pos, od);
+            pos = safecat(msg, sizeof msg, pos, ")");
+            pos = safecat(msg, sizeof msg, pos, "/");
+            pos = safecatn(msg, sizeof msg, pos, outmax);
+            pos = safecat(msg, sizeof msg, pos, " < ");
+            pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
+
+            if (pass == 0) /* The error condition */
+            {
+#              ifdef PNG_WARNINGS_SUPPORTED
+                  png_warning(vi->pp, msg);
+#              else
+                  store_warning(vi->pp, msg);
+#              endif
+            }
+
+            else /* logging this value */
+               store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
+         }
+      }
+   }
+
+   return i;
+}
+
+static void
+gamma_image_validate(gamma_display *dp, png_const_structp pp,
+   png_infop pi)
+{
+   /* Get some constants derived from the input and output file formats: */
+   const png_store* const ps = dp->this.ps;
+   png_byte in_ct = dp->this.colour_type;
+   png_byte in_bd = dp->this.bit_depth;
+   png_uint_32 w = dp->this.w;
+   png_uint_32 h = dp->this.h;
+   const size_t cbRow = dp->this.cbRow;
+   png_byte out_ct = png_get_color_type(pp, pi);
+   png_byte out_bd = png_get_bit_depth(pp, pi);
+
+   /* There are three sources of error, firstly the quantization in the
+    * file encoding, determined by sbit and/or the file depth, secondly
+    * the output (screen) gamma and thirdly the output file encoding.
+    *
+    * Since this API receives the screen and file gamma in double
+    * precision it is possible to calculate an exact answer given an input
+    * pixel value.  Therefore we assume that the *input* value is exact -
+    * sample/maxsample - calculate the corresponding gamma corrected
+    * output to the limits of double precision arithmetic and compare with
+    * what libpng returns.
+    *
+    * Since the library must quantize the output to 8 or 16 bits there is
+    * a fundamental limit on the accuracy of the output of +/-.5 - this
+    * quantization limit is included in addition to the other limits
+    * specified by the parameters to the API.  (Effectively, add .5
+    * everywhere.)
+    *
+    * The behavior of the 'sbit' parameter is defined by section 12.5
+    * (sample depth scaling) of the PNG spec.  That section forces the
+    * decoder to assume that the PNG values have been scaled if sBIT is
+    * present:
+    *
+    *     png-sample = floor( input-sample * (max-out/max-in) + .5);
+    *
+    * This means that only a subset of the possible PNG values should
+    * appear in the input. However, the spec allows the encoder to use a
+    * variety of approximations to the above and doesn't require any
+    * restriction of the values produced.
+    *
+    * Nevertheless the spec requires that the upper 'sBIT' bits of the
+    * value stored in a PNG file be the original sample bits.
+    * Consequently the code below simply scales the top sbit bits by
+    * (1<<sbit)-1 to obtain an original sample value.
+    *
+    * Because there is limited precision in the input it is arguable that
+    * an acceptable result is any valid result from input-.5 to input+.5.
+    * The basic tests below do not do this, however if 'use_input_precision'
+    * is set a subsequent test is performed above.
+    */
+   unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
+   int processing;
+   png_uint_32 y;
+   const store_palette_entry *in_palette = dp->this.palette;
+   int in_is_transparent = dp->this.is_transparent;
+   int process_tRNS;
+   int out_npalette = -1;
+   int out_is_transparent = 0; /* Just refers to the palette case */
+   store_palette out_palette;
+   validate_info vi;
+
+   /* Check for row overwrite errors */
+   store_image_check(dp->this.ps, pp, 0);
+
+   /* Supply the input and output sample depths here - 8 for an indexed image,
+    * otherwise the bit depth.
+    */
+   init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
+
+   processing = (vi.gamma_correction > 0 && !dp->threshold_test)
+      || in_bd != out_bd || in_ct != out_ct || vi.do_background;
+   process_tRNS = dp->this.has_tRNS && vi.do_background;
+
+   /* TODO: FIX THIS: MAJOR BUG!  If the transformations all happen inside
+    * the palette there is no way of finding out, because libpng fails to
+    * update the palette on png_read_update_info.  Indeed, libpng doesn't
+    * even do the required work until much later, when it doesn't have any
+    * info pointer.  Oops.  For the moment 'processing' is turned off if
+    * out_ct is palette.
+    */
+   if (in_ct == 3 && out_ct == 3)
+      processing = 0;
+
+   if (processing && out_ct == 3)
+      out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
+
+   for (y=0; y<h; ++y)
+   {
+      png_const_bytep pRow = store_image_row(ps, pp, 0, y);
+      png_byte std[STANDARD_ROWMAX];
+
+      transform_row(pp, std, in_ct, in_bd, y);
+
+      if (processing)
+      {
+         unsigned int x;
+
+         for (x=0; x<w; ++x)
+         {
+            double alpha = 1; /* serves as a flag value */
+
+            /* Record the palette index for index images. */
+            unsigned int in_index =
+               in_ct == 3 ? sample(std, 3, in_bd, x, 0, 0, 0) : 256;
+            unsigned int out_index =
+               out_ct == 3 ? sample(std, 3, out_bd, x, 0, 0, 0) : 256;
+
+            /* Handle input alpha - png_set_background will cause the output
+             * alpha to disappear so there is nothing to check.
+             */
+            if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 ||
+                (in_ct == 3 && in_is_transparent))
+            {
+               unsigned int input_alpha = in_ct == 3 ?
+                  dp->this.palette[in_index].alpha :
+                  sample(std, in_ct, in_bd, x, samples_per_pixel, 0, 0);
+
+               unsigned int output_alpha = 65536 /* as a flag value */;
+
+               if (out_ct == 3)
+               {
+                  if (out_is_transparent)
+                     output_alpha = out_palette[out_index].alpha;
+               }
+
+               else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
+                  output_alpha = sample(pRow, out_ct, out_bd, x,
+                     samples_per_pixel, 0, 0);
+
+               if (output_alpha != 65536)
+                  alpha = gamma_component_validate("alpha", &vi, input_alpha,
+                     output_alpha, -1/*alpha*/, 0/*background*/);
+
+               else /* no alpha in output */
+               {
+                  /* This is a copy of the calculation of 'i' above in order to
+                   * have the alpha value to use in the background calculation.
+                   */
+                  alpha = input_alpha >> vi.isbit_shift;
+                  alpha /= vi.sbit_max;
+               }
+            }
+
+            else if (process_tRNS)
+            {
+               /* alpha needs to be set appropriately for this pixel, it is
+                * currently 1 and needs to be 0 for an input pixel which matches
+                * the values in tRNS.
+                */
+               switch (in_ct)
+               {
+                  case 0: /* gray */
+                     if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
+                           dp->this.transparent.red)
+                        alpha = 0;
+                     break;
+
+                  case 2: /* RGB */
+                     if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
+                           dp->this.transparent.red &&
+                         sample(std, in_ct, in_bd, x, 1, 0, 0) ==
+                           dp->this.transparent.green &&
+                         sample(std, in_ct, in_bd, x, 2, 0, 0) ==
+                           dp->this.transparent.blue)
+                        alpha = 0;
+                     break;
+
+                  default:
+                     break;
+               }
+            }
+
+            /* Handle grayscale or RGB components. */
+            if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
+               (void)gamma_component_validate("gray", &vi,
+                  sample(std, in_ct, in_bd, x, 0, 0, 0),
+                  sample(pRow, out_ct, out_bd, x, 0, 0, 0),
+                  alpha/*component*/, vi.background_red);
+            else /* RGB or palette */
+            {
+               (void)gamma_component_validate("red", &vi,
+                  in_ct == 3 ? in_palette[in_index].red :
+                     sample(std, in_ct, in_bd, x, 0, 0, 0),
+                  out_ct == 3 ? out_palette[out_index].red :
+                     sample(pRow, out_ct, out_bd, x, 0, 0, 0),
+                  alpha/*component*/, vi.background_red);
+
+               (void)gamma_component_validate("green", &vi,
+                  in_ct == 3 ? in_palette[in_index].green :
+                     sample(std, in_ct, in_bd, x, 1, 0, 0),
+                  out_ct == 3 ? out_palette[out_index].green :
+                     sample(pRow, out_ct, out_bd, x, 1, 0, 0),
+                  alpha/*component*/, vi.background_green);
+
+               (void)gamma_component_validate("blue", &vi,
+                  in_ct == 3 ? in_palette[in_index].blue :
+                     sample(std, in_ct, in_bd, x, 2, 0, 0),
+                  out_ct == 3 ? out_palette[out_index].blue :
+                     sample(pRow, out_ct, out_bd, x, 2, 0, 0),
+                  alpha/*component*/, vi.background_blue);
+            }
+         }
+      }
+
+      else if (memcmp(std, pRow, cbRow) != 0)
+      {
+         char msg[64];
+
+         /* No transform is expected on the threshold tests. */
+         sprintf(msg, "gamma: below threshold row %lu changed",
+            (unsigned long)y);
+
+         png_error(pp, msg);
+      }
+   } /* row (y) loop */
+
+   dp->this.ps->validated = 1;
+}
+
+static void PNGCBAPI
+gamma_end(png_structp ppIn, png_infop pi)
+{
+   png_const_structp pp = ppIn;
+   gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
+
+   if (!dp->this.speed)
+      gamma_image_validate(dp, pp, pi);
+   else
+      dp->this.ps->validated = 1;
+}
+
+/* A single test run checking a gamma transformation.
+ *
+ * maxabs: maximum absolute error as a fraction
+ * maxout: maximum output error in the output units
+ * maxpc:  maximum percentage error (as a percentage)
+ */
+static void
+gamma_test(png_modifier *pmIn, png_byte colour_typeIn,
+    png_byte bit_depthIn, int palette_numberIn,
+    int interlace_typeIn,
+    const double file_gammaIn, const double screen_gammaIn,
+    png_byte sbitIn, int threshold_testIn,
+    const char *name,
+    int use_input_precisionIn, int scale16In,
+    int expand16In, int do_backgroundIn,
+    const png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
+{
+   gamma_display d;
+   context(&pmIn->this, fault);
+
+   gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
+      palette_numberIn, interlace_typeIn, 0, 0, 0),
+      file_gammaIn, screen_gammaIn, sbitIn,
+      threshold_testIn, use_input_precisionIn, scale16In,
+      expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
+
+   Try
+   {
+      png_structp pp;
+      png_infop pi;
+      gama_modification gama_mod;
+      srgb_modification srgb_mod;
+      sbit_modification sbit_mod;
+
+      /* For the moment don't use the png_modifier support here. */
+      d.pm->encoding_counter = 0;
+      modifier_set_encoding(d.pm); /* Just resets everything */
+      d.pm->current_gamma = d.file_gamma;
+
+      /* Make an appropriate modifier to set the PNG file gamma to the
+       * given gamma value and the sBIT chunk to the given precision.
+       */
+      d.pm->modifications = NULL;
+      gama_modification_init(&gama_mod, d.pm, d.file_gamma);
+      srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
+      if (d.sbit > 0)
+         sbit_modification_init(&sbit_mod, d.pm, d.sbit);
+
+      modification_reset(d.pm->modifications);
+
+      /* Get a png_struct for reading the image. */
+      pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
+      standard_palette_init(&d.this);
+
+      /* Introduce the correct read function. */
+      if (d.pm->this.progressive)
+      {
+         /* Share the row function with the standard implementation. */
+         png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
+            gamma_end);
+
+         /* Now feed data into the reader until we reach the end: */
+         modifier_progressive_read(d.pm, pp, pi);
+      }
+      else
+      {
+         /* modifier_read expects a png_modifier* */
+         png_set_read_fn(pp, d.pm, modifier_read);
+
+         /* Check the header values: */
+         png_read_info(pp, pi);
+
+         /* Process the 'info' requirements. Only one image is generated */
+         gamma_info_imp(&d, pp, pi);
+
+         sequential_row(&d.this, pp, pi, -1, 0);
+
+         if (!d.this.speed)
+            gamma_image_validate(&d, pp, pi);
+         else
+            d.this.ps->validated = 1;
+      }
+
+      modifier_reset(d.pm);
+
+      if (d.pm->log && !d.threshold_test && !d.this.speed)
+         fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
+            d.this.bit_depth, colour_types[d.this.colour_type], name,
+            d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
+
+      /* Log the summary values too. */
+      if (d.this.colour_type == 0 || d.this.colour_type == 4)
+      {
+         switch (d.this.bit_depth)
+         {
+         case 1:
+            break;
+
+         case 2:
+            if (d.maxerrout > d.pm->error_gray_2)
+               d.pm->error_gray_2 = d.maxerrout;
+
+            break;
+
+         case 4:
+            if (d.maxerrout > d.pm->error_gray_4)
+               d.pm->error_gray_4 = d.maxerrout;
+
+            break;
+
+         case 8:
+            if (d.maxerrout > d.pm->error_gray_8)
+               d.pm->error_gray_8 = d.maxerrout;
+
+            break;
+
+         case 16:
+            if (d.maxerrout > d.pm->error_gray_16)
+               d.pm->error_gray_16 = d.maxerrout;
+
+            break;
+
+         default:
+            png_error(pp, "bad bit depth (internal: 1)");
+         }
+      }
+
+      else if (d.this.colour_type == 2 || d.this.colour_type == 6)
+      {
+         switch (d.this.bit_depth)
+         {
+         case 8:
+
+            if (d.maxerrout > d.pm->error_color_8)
+               d.pm->error_color_8 = d.maxerrout;
+
+            break;
+
+         case 16:
+
+            if (d.maxerrout > d.pm->error_color_16)
+               d.pm->error_color_16 = d.maxerrout;
+
+            break;
+
+         default:
+            png_error(pp, "bad bit depth (internal: 2)");
+         }
+      }
+
+      else if (d.this.colour_type == 3)
+      {
+         if (d.maxerrout > d.pm->error_indexed)
+            d.pm->error_indexed = d.maxerrout;
+      }
+   }
+
+   Catch(fault)
+      modifier_reset(voidcast(png_modifier*,(void*)fault));
+}
+
+static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
+    png_byte bit_depth, int interlace_type, double file_gamma,
+    double screen_gamma)
+{
+   size_t pos = 0;
+   char name[64];
+   pos = safecat(name, sizeof name, pos, "threshold ");
+   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+   pos = safecat(name, sizeof name, pos, "/");
+   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+
+   (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
+      file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
+      0 /*no input precision*/,
+      0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
+      0 /*no background gamma*/);
+}
+
+static void
+perform_gamma_threshold_tests(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   /* Don't test more than one instance of each palette - it's pointless, in
+    * fact this test is somewhat excessive since libpng doesn't make this
+    * decision based on colour type or bit depth!
+    *
+    * CHANGED: now test two palettes and, as a side effect, images with and
+    * without tRNS.
+    */
+   while (next_format(&colour_type, &bit_depth, &palette_number,
+                      pm->test_lbg_gamma_threshold, pm->test_tRNS))
+      if (palette_number < 2)
+   {
+      double test_gamma = 1.0;
+      while (test_gamma >= .4)
+      {
+         /* There's little point testing the interlacing vs non-interlacing,
+          * but this can be set from the command line.
+          */
+         gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
+            test_gamma, 1/test_gamma);
+         test_gamma *= .95;
+      }
+
+      /* And a special test for sRGB */
+      gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
+          .45455, 2.2);
+
+      if (fail(pm))
+         return;
+   }
+}
+
+static void gamma_transform_test(png_modifier *pm,
+   png_byte colour_type, png_byte bit_depth,
+   int palette_number,
+   int interlace_type, const double file_gamma,
+   const double screen_gamma, png_byte sbit,
+   int use_input_precision, int scale16)
+{
+   size_t pos = 0;
+   char name[64];
+
+   if (sbit != bit_depth && sbit != 0)
+   {
+      pos = safecat(name, sizeof name, pos, "sbit(");
+      pos = safecatn(name, sizeof name, pos, sbit);
+      pos = safecat(name, sizeof name, pos, ") ");
+   }
+
+   else
+      pos = safecat(name, sizeof name, pos, "gamma ");
+
+   if (scale16)
+      pos = safecat(name, sizeof name, pos, "16to8 ");
+
+   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+   pos = safecat(name, sizeof name, pos, "->");
+   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+
+   gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
+      file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
+      scale16, pm->test_gamma_expand16, 0 , 0, 0);
+}
+
+static void perform_gamma_transform_tests(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   while (next_format(&colour_type, &bit_depth, &palette_number,
+                      pm->test_lbg_gamma_transform, pm->test_tRNS))
+   {
+      unsigned int i, j;
+
+      for (i=0; i<pm->ngamma_tests; ++i)
+      {
+         for (j=0; j<pm->ngamma_tests; ++j)
+         {
+            if (i != j)
+            {
+               gamma_transform_test(pm, colour_type, bit_depth, palette_number,
+                  pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
+                  0/*sBIT*/, pm->use_input_precision, 0/*do not scale16*/);
+
+               if (fail(pm))
+                  return;
+            }
+         }
+      }
+   }
+}
+
+static void perform_gamma_sbit_tests(png_modifier *pm)
+{
+   png_byte sbit;
+
+   /* The only interesting cases are colour and grayscale, alpha is ignored here
+    * for overall speed.  Only bit depths where sbit is less than the bit depth
+    * are tested.
+    */
+   for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
+   {
+      png_byte colour_type = 0, bit_depth = 0;
+      unsigned int npalette = 0;
+
+      while (next_format(&colour_type, &bit_depth, &npalette,
+                         pm->test_lbg_gamma_sbit, pm->test_tRNS))
+         if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
+            ((colour_type == 3 && sbit < 8) ||
+            (colour_type != 3 && sbit < bit_depth)))
+      {
+         unsigned int i;
+
+         for (i=0; i<pm->ngamma_tests; ++i)
+         {
+            unsigned int j;
+
+            for (j=0; j<pm->ngamma_tests; ++j)
+            {
+               if (i != j)
+               {
+                  gamma_transform_test(pm, colour_type, bit_depth, npalette,
+                     pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
+                     sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
+
+                  if (fail(pm))
+                     return;
+               }
+            }
+         }
+      }
+   }
+}
+
+/* Note that this requires a 16 bit source image but produces 8 bit output, so
+ * we only need the 16bit write support, but the 16 bit images are only
+ * generated if DO_16BIT is defined.
+ */
+#ifdef DO_16BIT
+static void perform_gamma_scale16_tests(png_modifier *pm)
+{
+#  ifndef PNG_MAX_GAMMA_8
+#     define PNG_MAX_GAMMA_8 11
+#  endif
+#  if defined PNG_MAX_GAMMA_8 || PNG_LIBPNG_VER < 10700
+#     define SBIT_16_TO_8 PNG_MAX_GAMMA_8
+#  else
+#     define SBIT_16_TO_8 16
+#  endif
+   /* Include the alpha cases here. Note that sbit matches the internal value
+    * used by the library - otherwise we will get spurious errors from the
+    * internal sbit style approximation.
+    *
+    * The threshold test is here because otherwise the 16 to 8 conversion will
+    * proceed *without* gamma correction, and the tests above will fail (but not
+    * by much) - this could be fixed, it only appears with the -g option.
+    */
+   unsigned int i, j;
+   for (i=0; i<pm->ngamma_tests; ++i)
+   {
+      for (j=0; j<pm->ngamma_tests; ++j)
+      {
+         if (i != j &&
+             fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
+         {
+            gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+
+            if (fail(pm))
+               return;
+
+            gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+
+            if (fail(pm))
+               return;
+
+            gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+
+            if (fail(pm))
+               return;
+
+            gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+
+            if (fail(pm))
+               return;
+         }
+      }
+   }
+}
+#endif /* 16 to 8 bit conversion */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+static void gamma_composition_test(png_modifier *pm,
+   png_byte colour_type, png_byte bit_depth,
+   int palette_number,
+   int interlace_type, const double file_gamma,
+   const double screen_gamma,
+   int use_input_precision, int do_background,
+   int expand_16)
+{
+   size_t pos = 0;
+   png_const_charp base;
+   double bg;
+   char name[128];
+   png_color_16 background;
+
+   /* Make up a name and get an appropriate background gamma value. */
+   switch (do_background)
+   {
+      default:
+         base = "";
+         bg = 4; /* should not be used */
+         break;
+      case PNG_BACKGROUND_GAMMA_SCREEN:
+         base = " bckg(Screen):";
+         bg = 1/screen_gamma;
+         break;
+      case PNG_BACKGROUND_GAMMA_FILE:
+         base = " bckg(File):";
+         bg = file_gamma;
+         break;
+      case PNG_BACKGROUND_GAMMA_UNIQUE:
+         base = " bckg(Unique):";
+         /* This tests the handling of a unique value, the math is such that the
+          * value tends to be <1, but is neither screen nor file (even if they
+          * match!)
+          */
+         bg = (file_gamma + screen_gamma) / 3;
+         break;
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
+         base = " alpha(PNG)";
+         bg = 4; /* should not be used */
+         break;
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+         base = " alpha(Porter-Duff)";
+         bg = 4; /* should not be used */
+         break;
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+         base = " alpha(Optimized)";
+         bg = 4; /* should not be used */
+         break;
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+         base = " alpha(Broken)";
+         bg = 4; /* should not be used */
+         break;
+#endif
+   }
+
+   /* Use random background values - the background is always presented in the
+    * output space (8 or 16 bit components).
+    */
+   if (expand_16 || bit_depth == 16)
+   {
+      png_uint_32 r = random_32();
+
+      background.red = (png_uint_16)r;
+      background.green = (png_uint_16)(r >> 16);
+      r = random_32();
+      background.blue = (png_uint_16)r;
+      background.gray = (png_uint_16)(r >> 16);
+
+      /* In earlier libpng versions, those where DIGITIZE is set, any background
+       * gamma correction in the expand16 case was done using 8-bit gamma
+       * correction tables, resulting in larger errors.  To cope with those
+       * cases use a 16-bit background value which will handle this gamma
+       * correction.
+       */
+#     if DIGITIZE
+         if (expand_16 && (do_background == PNG_BACKGROUND_GAMMA_UNIQUE ||
+                           do_background == PNG_BACKGROUND_GAMMA_FILE) &&
+            fabs(bg*screen_gamma-1) > PNG_GAMMA_THRESHOLD)
+         {
+            /* The background values will be looked up in an 8-bit table to do
+             * the gamma correction, so only select values which are an exact
+             * match for the 8-bit table entries:
+             */
+            background.red = (png_uint_16)((background.red >> 8) * 257);
+            background.green = (png_uint_16)((background.green >> 8) * 257);
+            background.blue = (png_uint_16)((background.blue >> 8) * 257);
+            background.gray = (png_uint_16)((background.gray >> 8) * 257);
+         }
+#     endif
+   }
+
+   else /* 8 bit colors */
+   {
+      png_uint_32 r = random_32();
+
+      background.red = (png_byte)r;
+      background.green = (png_byte)(r >> 8);
+      background.blue = (png_byte)(r >> 16);
+      background.gray = (png_byte)(r >> 24);
+   }
+
+   background.index = 193; /* rgb(193,193,193) to detect errors */
+
+   if (!(colour_type & PNG_COLOR_MASK_COLOR))
+   {
+      /* Because, currently, png_set_background is always called with
+       * 'need_expand' false in this case and because the gamma test itself
+       * doesn't cause an expand to 8-bit for lower bit depths the colour must
+       * be reduced to the correct range.
+       */
+      if (bit_depth < 8)
+         background.gray &= (png_uint_16)((1U << bit_depth)-1);
+
+      /* Grayscale input, we do not convert to RGB (TBD), so we must set the
+       * background to gray - else libpng seems to fail.
+       */
+      background.red = background.green = background.blue = background.gray;
+   }
+
+   pos = safecat(name, sizeof name, pos, "gamma ");
+   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+   pos = safecat(name, sizeof name, pos, "->");
+   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+
+   pos = safecat(name, sizeof name, pos, base);
+   if (do_background < ALPHA_MODE_OFFSET)
+   {
+      /* Include the background color and gamma in the name: */
+      pos = safecat(name, sizeof name, pos, "(");
+      /* This assumes no expand gray->rgb - the current code won't handle that!
+       */
+      if (colour_type & PNG_COLOR_MASK_COLOR)
+      {
+         pos = safecatn(name, sizeof name, pos, background.red);
+         pos = safecat(name, sizeof name, pos, ",");
+         pos = safecatn(name, sizeof name, pos, background.green);
+         pos = safecat(name, sizeof name, pos, ",");
+         pos = safecatn(name, sizeof name, pos, background.blue);
+      }
+      else
+         pos = safecatn(name, sizeof name, pos, background.gray);
+      pos = safecat(name, sizeof name, pos, ")^");
+      pos = safecatd(name, sizeof name, pos, bg, 3);
+   }
+
+   gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
+      file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
+      0/*strip 16*/, expand_16, do_background, &background, bg);
+}
+
+
+static void
+perform_gamma_composition_tests(png_modifier *pm, int do_background,
+   int expand_16)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   unsigned int palette_number = 0;
+
+   /* Skip the non-alpha cases - there is no setting of a transparency colour at
+    * present.
+    *
+    * TODO: incorrect; the palette case sets tRNS and, now RGB and gray do,
+    * however the palette case fails miserably so is commented out below.
+    */
+   while (next_format(&colour_type, &bit_depth, &palette_number,
+                      pm->test_lbg_gamma_composition, pm->test_tRNS))
+      if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0
+#if 0 /* TODO: FIXME */
+          /*TODO: FIXME: this should work */
+          || colour_type == 3
+#endif
+          || (colour_type != 3 && palette_number != 0))
+   {
+      unsigned int i, j;
+
+      /* Don't skip the i==j case here - it's relevant. */
+      for (i=0; i<pm->ngamma_tests; ++i)
+      {
+         for (j=0; j<pm->ngamma_tests; ++j)
+         {
+            gamma_composition_test(pm, colour_type, bit_depth, palette_number,
+               pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
+               pm->use_input_precision, do_background, expand_16);
+
+            if (fail(pm))
+               return;
+         }
+      }
+   }
+}
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
+
+static void
+init_gamma_errors(png_modifier *pm)
+{
+   /* Use -1 to catch tests that were not actually run */
+   pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = -1.;
+   pm->error_color_8 = -1.;
+   pm->error_indexed = -1.;
+   pm->error_gray_16 = pm->error_color_16 = -1.;
+}
+
+static void
+print_one(const char *leader, double err)
+{
+   if (err != -1.)
+      printf(" %s %.5f\n", leader, err);
+}
+
+static void
+summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth,
+   int indexed)
+{
+   fflush(stderr);
+
+   if (who)
+      printf("\nGamma correction with %s:\n", who);
+
+   else
+      printf("\nBasic gamma correction:\n");
+
+   if (low_bit_depth)
+   {
+      print_one(" 2 bit gray: ", pm->error_gray_2);
+      print_one(" 4 bit gray: ", pm->error_gray_4);
+      print_one(" 8 bit gray: ", pm->error_gray_8);
+      print_one(" 8 bit color:", pm->error_color_8);
+      if (indexed)
+         print_one(" indexed:    ", pm->error_indexed);
+   }
+
+   print_one("16 bit gray: ", pm->error_gray_16);
+   print_one("16 bit color:", pm->error_color_16);
+
+   fflush(stdout);
+}
+
+static void
+perform_gamma_test(png_modifier *pm, int summary)
+{
+   /*TODO: remove this*/
+   /* Save certain values for the temporary overrides below. */
+   unsigned int calculations_use_input_precision =
+      pm->calculations_use_input_precision;
+#  ifdef PNG_READ_BACKGROUND_SUPPORTED
+      double maxout8 = pm->maxout8;
+#  endif
+
+   /* First some arbitrary no-transform tests: */
+   if (!pm->this.speed && pm->test_gamma_threshold)
+   {
+      perform_gamma_threshold_tests(pm);
+
+      if (fail(pm))
+         return;
+   }
+
+   /* Now some real transforms. */
+   if (pm->test_gamma_transform)
+   {
+      if (summary)
+      {
+         fflush(stderr);
+         printf("Gamma correction error summary\n\n");
+         printf("The printed value is the maximum error in the pixel values\n");
+         printf("calculated by the libpng gamma correction code.  The error\n");
+         printf("is calculated as the difference between the output pixel\n");
+         printf("value (always an integer) and the ideal value from the\n");
+         printf("libpng specification (typically not an integer).\n\n");
+
+         printf("Expect this value to be less than .5 for 8 bit formats,\n");
+         printf("less than 1 for formats with fewer than 8 bits and a small\n");
+         printf("number (typically less than 5) for the 16 bit formats.\n");
+         printf("For performance reasons the value for 16 bit formats\n");
+         printf("increases when the image file includes an sBIT chunk.\n");
+         fflush(stdout);
+      }
+
+      init_gamma_errors(pm);
+      /*TODO: remove this.  Necessary because the current libpng
+       * implementation works in 8 bits:
+       */
+      if (pm->test_gamma_expand16)
+         pm->calculations_use_input_precision = 1;
+      perform_gamma_transform_tests(pm);
+      if (!calculations_use_input_precision)
+         pm->calculations_use_input_precision = 0;
+
+      if (summary)
+         summarize_gamma_errors(pm, NULL/*who*/, 1/*low bit depth*/, 1/*indexed*/);
+
+      if (fail(pm))
+         return;
+   }
+
+   /* The sbit tests produce much larger errors: */
+   if (pm->test_gamma_sbit)
+   {
+      init_gamma_errors(pm);
+      perform_gamma_sbit_tests(pm);
+
+      if (summary)
+         summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U, 1/*indexed*/);
+
+      if (fail(pm))
+         return;
+   }
+
+#ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
+   if (pm->test_gamma_scale16)
+   {
+      /* The 16 to 8 bit strip operations: */
+      init_gamma_errors(pm);
+      perform_gamma_scale16_tests(pm);
+
+      if (summary)
+      {
+         fflush(stderr);
+         printf("\nGamma correction with 16 to 8 bit reduction:\n");
+         printf(" 16 bit gray:  %.5f\n", pm->error_gray_16);
+         printf(" 16 bit color: %.5f\n", pm->error_color_16);
+         fflush(stdout);
+      }
+
+      if (fail(pm))
+         return;
+   }
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+   if (pm->test_gamma_background)
+   {
+      init_gamma_errors(pm);
+
+      /*TODO: remove this.  Necessary because the current libpng
+       * implementation works in 8 bits:
+       */
+      if (pm->test_gamma_expand16)
+      {
+         pm->calculations_use_input_precision = 1;
+         pm->maxout8 = .499; /* because the 16 bit background is smashed */
+      }
+      perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
+         pm->test_gamma_expand16);
+      if (!calculations_use_input_precision)
+         pm->calculations_use_input_precision = 0;
+      pm->maxout8 = maxout8;
+
+      if (summary)
+         summarize_gamma_errors(pm, "background", 1, 0/*indexed*/);
+
+      if (fail(pm))
+         return;
+   }
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+   if (pm->test_gamma_alpha_mode)
+   {
+      int do_background;
+
+      init_gamma_errors(pm);
+
+      /*TODO: remove this.  Necessary because the current libpng
+       * implementation works in 8 bits:
+       */
+      if (pm->test_gamma_expand16)
+         pm->calculations_use_input_precision = 1;
+      for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
+         do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
+         ++do_background)
+         perform_gamma_composition_tests(pm, do_background,
+            pm->test_gamma_expand16);
+      if (!calculations_use_input_precision)
+         pm->calculations_use_input_precision = 0;
+
+      if (summary)
+         summarize_gamma_errors(pm, "alpha mode", 1, 0/*indexed*/);
+
+      if (fail(pm))
+         return;
+   }
+#endif
+}
+#endif /* PNG_READ_GAMMA_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED */
+
+/* INTERLACE MACRO VALIDATION */
+/* This is copied verbatim from the specification, it is simply the pass
+ * number in which each pixel in each 8x8 tile appears.  The array must
+ * be indexed adam7[y][x] and notice that the pass numbers are based at
+ * 1, not 0 - the base libpng uses.
+ */
+static const
+png_byte adam7[8][8] =
+{
+   { 1,6,4,6,2,6,4,6 },
+   { 7,7,7,7,7,7,7,7 },
+   { 5,6,5,6,5,6,5,6 },
+   { 7,7,7,7,7,7,7,7 },
+   { 3,6,4,6,3,6,4,6 },
+   { 7,7,7,7,7,7,7,7 },
+   { 5,6,5,6,5,6,5,6 },
+   { 7,7,7,7,7,7,7,7 }
+};
+
+/* This routine validates all the interlace support macros in png.h for
+ * a variety of valid PNG widths and heights.  It uses a number of similarly
+ * named internal routines that feed off the above array.
+ */
+static png_uint_32
+png_pass_start_row(int pass)
+{
+   int x, y;
+   ++pass;
+   for (y=0; y<8; ++y)
+      for (x=0; x<8; ++x)
+         if (adam7[y][x] == pass)
+            return y;
+   return 0xf;
+}
+
+static png_uint_32
+png_pass_start_col(int pass)
+{
+   int x, y;
+   ++pass;
+   for (x=0; x<8; ++x)
+      for (y=0; y<8; ++y)
+         if (adam7[y][x] == pass)
+            return x;
+   return 0xf;
+}
+
+static int
+png_pass_row_shift(int pass)
+{
+   int x, y, base=(-1), inc=8;
+   ++pass;
+   for (y=0; y<8; ++y)
+   {
+      for (x=0; x<8; ++x)
+      {
+         if (adam7[y][x] == pass)
+         {
+            if (base == (-1))
+               base = y;
+            else if (base == y)
+               {}
+            else if (inc == y-base)
+               base=y;
+            else if (inc == 8)
+               inc = y-base, base=y;
+            else if (inc != y-base)
+               return 0xff; /* error - more than one 'inc' value! */
+         }
+      }
+   }
+
+   if (base == (-1)) return 0xfe; /* error - no row in pass! */
+
+   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
+   switch (inc)
+   {
+case 2: return 1;
+case 4: return 2;
+case 8: return 3;
+default: break;
+   }
+
+   /* error - unrecognized 'inc' */
+   return (inc << 8) + 0xfd;
+}
+
+static int
+png_pass_col_shift(int pass)
+{
+   int x, y, base=(-1), inc=8;
+   ++pass;
+   for (x=0; x<8; ++x)
+   {
+      for (y=0; y<8; ++y)
+      {
+         if (adam7[y][x] == pass)
+         {
+            if (base == (-1))
+               base = x;
+            else if (base == x)
+               {}
+            else if (inc == x-base)
+               base=x;
+            else if (inc == 8)
+               inc = x-base, base=x;
+            else if (inc != x-base)
+               return 0xff; /* error - more than one 'inc' value! */
+         }
+      }
+   }
+
+   if (base == (-1)) return 0xfe; /* error - no row in pass! */
+
+   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
+   switch (inc)
+   {
+case 1: return 0; /* pass 7 has all the columns */
+case 2: return 1;
+case 4: return 2;
+case 8: return 3;
+default: break;
+   }
+
+   /* error - unrecognized 'inc' */
+   return (inc << 8) + 0xfd;
+}
+
+static png_uint_32
+png_row_from_pass_row(png_uint_32 yIn, int pass)
+{
+   /* By examination of the array: */
+   switch (pass)
+   {
+case 0: return yIn * 8;
+case 1: return yIn * 8;
+case 2: return yIn * 8 + 4;
+case 3: return yIn * 4;
+case 4: return yIn * 4 + 2;
+case 5: return yIn * 2;
+case 6: return yIn * 2 + 1;
+default: break;
+   }
+
+   return 0xff; /* bad pass number */
+}
+
+static png_uint_32
+png_col_from_pass_col(png_uint_32 xIn, int pass)
+{
+   /* By examination of the array: */
+   switch (pass)
+   {
+case 0: return xIn * 8;
+case 1: return xIn * 8 + 4;
+case 2: return xIn * 4;
+case 3: return xIn * 4 + 2;
+case 4: return xIn * 2;
+case 5: return xIn * 2 + 1;
+case 6: return xIn;
+default: break;
+   }
+
+   return 0xff; /* bad pass number */
+}
+
+static int
+png_row_in_interlace_pass(png_uint_32 y, int pass)
+{
+   /* Is row 'y' in pass 'pass'? */
+   int x;
+   y &= 7;
+   ++pass;
+   for (x=0; x<8; ++x)
+      if (adam7[y][x] == pass)
+         return 1;
+
+   return 0;
+}
+
+static int
+png_col_in_interlace_pass(png_uint_32 x, int pass)
+{
+   /* Is column 'x' in pass 'pass'? */
+   int y;
+   x &= 7;
+   ++pass;
+   for (y=0; y<8; ++y)
+      if (adam7[y][x] == pass)
+         return 1;
+
+   return 0;
+}
+
+static png_uint_32
+png_pass_rows(png_uint_32 height, int pass)
+{
+   png_uint_32 tiles = height>>3;
+   png_uint_32 rows = 0;
+   unsigned int x, y;
+
+   height &= 7;
+   ++pass;
+   for (y=0; y<8; ++y)
+   {
+      for (x=0; x<8; ++x)
+      {
+         if (adam7[y][x] == pass)
+         {
+            rows += tiles;
+            if (y < height) ++rows;
+            break; /* i.e. break the 'x', column, loop. */
+         }
+      }
+   }
+
+   return rows;
+}
+
+static png_uint_32
+png_pass_cols(png_uint_32 width, int pass)
+{
+   png_uint_32 tiles = width>>3;
+   png_uint_32 cols = 0;
+   unsigned int x, y;
+
+   width &= 7;
+   ++pass;
+   for (x=0; x<8; ++x)
+   {
+      for (y=0; y<8; ++y)
+      {
+         if (adam7[y][x] == pass)
+         {
+            cols += tiles;
+            if (x < width) ++cols;
+            break; /* i.e. break the 'y', row, loop. */
+         }
+      }
+   }
+
+   return cols;
+}
+
+static void
+perform_interlace_macro_validation(void)
+{
+   /* The macros to validate, first those that depend only on pass:
+    *
+    * PNG_PASS_START_ROW(pass)
+    * PNG_PASS_START_COL(pass)
+    * PNG_PASS_ROW_SHIFT(pass)
+    * PNG_PASS_COL_SHIFT(pass)
+    */
+   int pass;
+
+   for (pass=0; pass<7; ++pass)
+   {
+      png_uint_32 m, f, v;
+
+      m = PNG_PASS_START_ROW(pass);
+      f = png_pass_start_row(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
+         exit(99);
+      }
+
+      m = PNG_PASS_START_COL(pass);
+      f = png_pass_start_col(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
+         exit(99);
+      }
+
+      m = PNG_PASS_ROW_SHIFT(pass);
+      f = png_pass_row_shift(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
+         exit(99);
+      }
+
+      m = PNG_PASS_COL_SHIFT(pass);
+      f = png_pass_col_shift(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
+         exit(99);
+      }
+
+      /* Macros that depend on the image or sub-image height too:
+       *
+       * PNG_PASS_ROWS(height, pass)
+       * PNG_PASS_COLS(width, pass)
+       * PNG_ROW_FROM_PASS_ROW(yIn, pass)
+       * PNG_COL_FROM_PASS_COL(xIn, pass)
+       * PNG_ROW_IN_INTERLACE_PASS(y, pass)
+       * PNG_COL_IN_INTERLACE_PASS(x, pass)
+       */
+      for (v=0;;)
+      {
+         /* The first two tests overflow if the pass row or column is outside
+          * the possible range for a 32-bit result.  In fact the values should
+          * never be outside the range for a 31-bit result, but checking for 32
+          * bits here ensures that if an app uses a bogus pass row or column
+          * (just so long as it fits in a 32 bit integer) it won't get a
+          * possibly dangerous overflow.
+          */
+         /* First the base 0 stuff: */
+         if (v < png_pass_rows(0xFFFFFFFFU, pass))
+         {
+            m = PNG_ROW_FROM_PASS_ROW(v, pass);
+            f = png_row_from_pass_row(v, pass);
+            if (m != f)
+            {
+               fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
+                  v, pass, m, f);
+               exit(99);
+            }
+         }
+
+         if (v < png_pass_cols(0xFFFFFFFFU, pass))
+         {
+            m = PNG_COL_FROM_PASS_COL(v, pass);
+            f = png_col_from_pass_col(v, pass);
+            if (m != f)
+            {
+               fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
+                  v, pass, m, f);
+               exit(99);
+            }
+         }
+
+         m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
+         f = png_row_in_interlace_pass(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
+         }
+
+         m = PNG_COL_IN_INTERLACE_PASS(v, pass);
+         f = png_col_in_interlace_pass(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
+         }
+
+         /* Then the base 1 stuff: */
+         ++v;
+         m = PNG_PASS_ROWS(v, pass);
+         f = png_pass_rows(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
+         }
+
+         m = PNG_PASS_COLS(v, pass);
+         f = png_pass_cols(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(99);
+         }
+
+         /* Move to the next v - the stepping algorithm starts skipping
+          * values above 1024.
+          */
+         if (v > 1024)
+         {
+            if (v == PNG_UINT_31_MAX)
+               break;
+
+            v = (v << 1) ^ v;
+            if (v >= PNG_UINT_31_MAX)
+               v = PNG_UINT_31_MAX-1;
+         }
+      }
+   }
+}
+
+/* Test color encodings. These values are back-calculated from the published
+ * chromaticities.  The values are accurate to about 14 decimal places; 15 are
+ * given.  These values are much more accurate than the ones given in the spec,
+ * which typically don't exceed 4 decimal places.  This allows testing of the
+ * libpng code to its theoretical accuracy of 4 decimal places.  (If pngvalid
+ * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
+ * more.)
+ *
+ * The png_modifier code assumes that encodings[0] is sRGB and treats it
+ * specially: do not change the first entry in this list!
+ */
+static const color_encoding test_encodings[] =
+{
+/* sRGB: must be first in this list! */
+/*gamma:*/ { 1/2.2,
+/*red:  */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
+/*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
+/*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
+/* Kodak ProPhoto (wide gamut) */
+/*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
+/*red:  */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
+/*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
+/*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
+/* Adobe RGB (1998) */
+/*gamma:*/ { 1/(2+51./256),
+/*red:  */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
+/*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
+/*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
+/* Adobe Wide Gamut RGB */
+/*gamma:*/ { 1/(2+51./256),
+/*red:  */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
+/*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
+/*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
+/* Fake encoding which selects just the green channel */
+/*gamma:*/ { 1.45/2.2, /* the 'Mac' gamma */
+/*red:  */ { 0.716500716779386, 0.000000000000000, 0.000000000000000 },
+/*green:*/ { 0.101020574397477, 1.000000000000000, 0.051211818965388 },
+/*blue: */ { 0.146774385252705, 0.000000000000000, 0.773892783545073} },
+};
+
+/* signal handler
+ *
+ * This attempts to trap signals and escape without crashing.  It needs a
+ * context pointer so that it can throw an exception (call longjmp) to recover
+ * from the condition; this is handled by making the png_modifier used by 'main'
+ * into a global variable.
+ */
+static png_modifier pm;
+
+static void signal_handler(int signum)
+{
+
+   size_t pos = 0;
+   char msg[64];
+
+   pos = safecat(msg, sizeof msg, pos, "caught signal: ");
+
+   switch (signum)
+   {
+      case SIGABRT:
+         pos = safecat(msg, sizeof msg, pos, "abort");
+         break;
+
+      case SIGFPE:
+         pos = safecat(msg, sizeof msg, pos, "floating point exception");
+         break;
+
+      case SIGILL:
+         pos = safecat(msg, sizeof msg, pos, "illegal instruction");
+         break;
+
+      case SIGINT:
+         pos = safecat(msg, sizeof msg, pos, "interrupt");
+         break;
+
+      case SIGSEGV:
+         pos = safecat(msg, sizeof msg, pos, "invalid memory access");
+         break;
+
+      case SIGTERM:
+         pos = safecat(msg, sizeof msg, pos, "termination request");
+         break;
+
+      default:
+         pos = safecat(msg, sizeof msg, pos, "unknown ");
+         pos = safecatn(msg, sizeof msg, pos, signum);
+         break;
+   }
+
+   store_log(&pm.this, NULL/*png_structp*/, msg, 1/*error*/);
+
+   /* And finally throw an exception so we can keep going, unless this is
+    * SIGTERM in which case stop now.
+    */
+   if (signum != SIGTERM)
+   {
+      struct exception_context *the_exception_context =
+         &pm.this.exception_context;
+
+      Throw &pm.this;
+   }
+
+   else
+      exit(1);
+}
+
+/* main program */
+int main(int argc, char **argv)
+{
+   int summary = 1;  /* Print the error summary at the end */
+   int memstats = 0; /* Print memory statistics at the end */
+
+   /* Create the given output file on success: */
+   const char *touch = NULL;
+
+   /* This is an array of standard gamma values (believe it or not I've seen
+    * every one of these mentioned somewhere.)
+    *
+    * In the following list the most useful values are first!
+    */
+   static double
+      gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
+
+   /* This records the command and arguments: */
+   size_t cp = 0;
+   char command[1024];
+
+   anon_context(&pm.this);
+
+   gnu_volatile(summary)
+   gnu_volatile(memstats)
+   gnu_volatile(touch)
+
+   /* Add appropriate signal handlers, just the ANSI specified ones: */
+   signal(SIGABRT, signal_handler);
+   signal(SIGFPE, signal_handler);
+   signal(SIGILL, signal_handler);
+   signal(SIGINT, signal_handler);
+   signal(SIGSEGV, signal_handler);
+   signal(SIGTERM, signal_handler);
+
+#ifdef HAVE_FEENABLEEXCEPT
+   /* Only required to enable FP exceptions on platforms where they start off
+    * disabled; this is not necessary but if it is not done pngvalid will likely
+    * end up ignoring FP conditions that other platforms fault.
+    */
+   feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
+#endif
+
+   modifier_init(&pm);
+
+   /* Preallocate the image buffer, because we know how big it needs to be,
+    * note that, for testing purposes, it is deliberately mis-aligned by tag
+    * bytes either side.  All rows have an additional five bytes of padding for
+    * overwrite checking.
+    */
+   store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
+
+   /* Don't give argv[0], it's normally some horrible libtool string: */
+   cp = safecat(command, sizeof command, cp, "pngvalid");
+
+   /* Default to error on warning: */
+   pm.this.treat_warnings_as_errors = 1;
+
+   /* Default assume_16_bit_calculations appropriately; this tells the checking
+    * code that 16-bit arithmetic is used for 8-bit samples when it would make a
+    * difference.
+    */
+   pm.assume_16_bit_calculations = PNG_LIBPNG_VER >= 10700;
+
+   /* Currently 16 bit expansion happens at the end of the pipeline, so the
+    * calculations are done in the input bit depth not the output.
+    *
+    * TODO: fix this
+    */
+   pm.calculations_use_input_precision = 1U;
+
+   /* Store the test gammas */
+   pm.gammas = gammas;
+   pm.ngammas = ARRAY_SIZE(gammas);
+   pm.ngamma_tests = 0; /* default to off */
+
+   /* Low bit depth gray images don't do well in the gamma tests, until
+    * this is fixed turn them off for some gamma cases:
+    */
+#  ifdef PNG_WRITE_tRNS_SUPPORTED
+      pm.test_tRNS = 1;
+#  endif
+   pm.test_lbg = PNG_LIBPNG_VER >= 10600;
+   pm.test_lbg_gamma_threshold = 1;
+   pm.test_lbg_gamma_transform = PNG_LIBPNG_VER >= 10600;
+   pm.test_lbg_gamma_sbit = 1;
+   pm.test_lbg_gamma_composition = PNG_LIBPNG_VER >= 10700;
+
+   /* And the test encodings */
+   pm.encodings = test_encodings;
+   pm.nencodings = ARRAY_SIZE(test_encodings);
+
+#  if PNG_LIBPNG_VER < 10700
+      pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
+#  else
+      pm.sbitlow = 1U;
+#  endif
+
+   /* The following allows results to pass if they correspond to anything in the
+    * transformed range [input-.5,input+.5]; this is is required because of the
+    * way libpng treats the 16_TO_8 flag when building the gamma tables in
+    * releases up to 1.6.0.
+    *
+    * TODO: review this
+    */
+   pm.use_input_precision_16to8 = 1U;
+   pm.use_input_precision_sbit = 1U; /* because libpng now rounds sBIT */
+
+   /* Some default values (set the behavior for 'make check' here).
+    * These values simply control the maximum error permitted in the gamma
+    * transformations.  The practical limits for human perception are described
+    * below (the setting for maxpc16), however for 8 bit encodings it isn't
+    * possible to meet the accepted capabilities of human vision - i.e. 8 bit
+    * images can never be good enough, regardless of encoding.
+    */
+   pm.maxout8 = .1;     /* Arithmetic error in *encoded* value */
+   pm.maxabs8 = .00005; /* 1/20000 */
+   pm.maxcalc8 = 1./255;  /* +/-1 in 8 bits for compose errors */
+   pm.maxpc8 = .499;    /* I.e., .499% fractional error */
+   pm.maxout16 = .499;  /* Error in *encoded* value */
+   pm.maxabs16 = .00005;/* 1/20000 */
+   pm.maxcalc16 =1./65535;/* +/-1 in 16 bits for compose errors */
+#  if PNG_LIBPNG_VER < 10700
+      pm.maxcalcG = 1./((1<<PNG_MAX_GAMMA_8)-1);
+#  else
+      pm.maxcalcG = 1./((1<<16)-1);
+#  endif
+
+   /* NOTE: this is a reasonable perceptual limit. We assume that humans can
+    * perceive light level differences of 1% over a 100:1 range, so we need to
+    * maintain 1 in 10000 accuracy (in linear light space), which is what the
+    * following guarantees.  It also allows significantly higher errors at
+    * higher 16 bit values, which is important for performance.  The actual
+    * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
+    * this is only allowed for values >38149 by the following:
+    */
+   pm.maxpc16 = .005;   /* I.e., 1/200% - 1/20000 */
+
+   /* Now parse the command line options. */
+   while (--argc >= 1)
+   {
+      int catmore = 0; /* Set if the argument has an argument. */
+
+      /* Record each argument for posterity: */
+      cp = safecat(command, sizeof command, cp, " ");
+      cp = safecat(command, sizeof command, cp, *++argv);
+
+      if (strcmp(*argv, "-v") == 0)
+         pm.this.verbose = 1;
+
+      else if (strcmp(*argv, "-l") == 0)
+         pm.log = 1;
+
+      else if (strcmp(*argv, "-q") == 0)
+         summary = pm.this.verbose = pm.log = 0;
+
+      else if (strcmp(*argv, "-w") == 0 ||
+               strcmp(*argv, "--strict") == 0)
+         pm.this.treat_warnings_as_errors = 1; /* NOTE: this is the default! */
+
+      else if (strcmp(*argv, "--nostrict") == 0)
+         pm.this.treat_warnings_as_errors = 0;
+
+      else if (strcmp(*argv, "--speed") == 0)
+         pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
+            summary = 0;
+
+      else if (strcmp(*argv, "--memory") == 0)
+         memstats = 1;
+
+      else if (strcmp(*argv, "--size") == 0)
+         pm.test_size = 1;
+
+      else if (strcmp(*argv, "--nosize") == 0)
+         pm.test_size = 0;
+
+      else if (strcmp(*argv, "--standard") == 0)
+         pm.test_standard = 1;
+
+      else if (strcmp(*argv, "--nostandard") == 0)
+         pm.test_standard = 0;
+
+      else if (strcmp(*argv, "--transform") == 0)
+         pm.test_transform = 1;
+
+      else if (strcmp(*argv, "--notransform") == 0)
+         pm.test_transform = 0;
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+      else if (strncmp(*argv, "--transform-disable=",
+         sizeof "--transform-disable") == 0)
+      {
+         pm.test_transform = 1;
+         transform_disable(*argv + sizeof "--transform-disable");
+      }
+
+      else if (strncmp(*argv, "--transform-enable=",
+         sizeof "--transform-enable") == 0)
+      {
+         pm.test_transform = 1;
+         transform_enable(*argv + sizeof "--transform-enable");
+      }
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+      else if (strcmp(*argv, "--gamma") == 0)
+      {
+         /* Just do two gamma tests here (2.2 and linear) for speed: */
+         pm.ngamma_tests = 2U;
+         pm.test_gamma_threshold = 1;
+         pm.test_gamma_transform = 1;
+         pm.test_gamma_sbit = 1;
+         pm.test_gamma_scale16 = 1;
+         pm.test_gamma_background = 1; /* composition */
+         pm.test_gamma_alpha_mode = 1;
+      }
+
+      else if (strcmp(*argv, "--nogamma") == 0)
+         pm.ngamma_tests = 0;
+
+      else if (strcmp(*argv, "--gamma-threshold") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
+
+      else if (strcmp(*argv, "--nogamma-threshold") == 0)
+         pm.test_gamma_threshold = 0;
+
+      else if (strcmp(*argv, "--gamma-transform") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
+
+      else if (strcmp(*argv, "--nogamma-transform") == 0)
+         pm.test_gamma_transform = 0;
+
+      else if (strcmp(*argv, "--gamma-sbit") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
+
+      else if (strcmp(*argv, "--nogamma-sbit") == 0)
+         pm.test_gamma_sbit = 0;
+
+      else if (strcmp(*argv, "--gamma-16-to-8") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
+
+      else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
+         pm.test_gamma_scale16 = 0;
+
+      else if (strcmp(*argv, "--gamma-background") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
+
+      else if (strcmp(*argv, "--nogamma-background") == 0)
+         pm.test_gamma_background = 0;
+
+      else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
+
+      else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
+         pm.test_gamma_alpha_mode = 0;
+
+      else if (strcmp(*argv, "--expand16") == 0)
+      {
+#        ifdef PNG_READ_EXPAND_16_SUPPORTED
+            pm.test_gamma_expand16 = 1;
+#        else
+            fprintf(stderr, "pngvalid: --expand16: no read support\n");
+            return SKIP;
+#        endif
+      }
+
+      else if (strcmp(*argv, "--noexpand16") == 0)
+         pm.test_gamma_expand16 = 0;
+
+      else if (strcmp(*argv, "--low-depth-gray") == 0)
+         pm.test_lbg = pm.test_lbg_gamma_threshold =
+            pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
+            pm.test_lbg_gamma_composition = 1;
+
+      else if (strcmp(*argv, "--nolow-depth-gray") == 0)
+         pm.test_lbg = pm.test_lbg_gamma_threshold =
+            pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
+            pm.test_lbg_gamma_composition = 0;
+
+      else if (strcmp(*argv, "--tRNS") == 0)
+      {
+#        ifdef PNG_WRITE_tRNS_SUPPORTED
+            pm.test_tRNS = 1;
+#        else
+            fprintf(stderr, "pngvalid: --tRNS: no write support\n");
+            return SKIP;
+#        endif
+      }
+
+      else if (strcmp(*argv, "--notRNS") == 0)
+         pm.test_tRNS = 0;
+
+      else if (strcmp(*argv, "--more-gammas") == 0)
+         pm.ngamma_tests = 3U;
+
+      else if (strcmp(*argv, "--all-gammas") == 0)
+         pm.ngamma_tests = pm.ngammas;
+
+      else if (strcmp(*argv, "--progressive-read") == 0)
+         pm.this.progressive = 1;
+
+      else if (strcmp(*argv, "--use-update-info") == 0)
+         ++pm.use_update_info; /* Can call multiple times */
+
+      else if (strcmp(*argv, "--interlace") == 0)
+      {
+#        if CAN_WRITE_INTERLACE
+            pm.interlace_type = PNG_INTERLACE_ADAM7;
+#        else /* !CAN_WRITE_INTERLACE */
+            fprintf(stderr, "pngvalid: no write interlace support\n");
+            return SKIP;
+#        endif /* !CAN_WRITE_INTERLACE */
+      }
+
+      else if (strcmp(*argv, "--use-input-precision") == 0)
+         pm.use_input_precision = 1U;
+
+      else if (strcmp(*argv, "--use-calculation-precision") == 0)
+         pm.use_input_precision = 0;
+
+      else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
+         pm.calculations_use_input_precision = 1U;
+
+      else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
+         pm.assume_16_bit_calculations = 1U;
+
+      else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
+         pm.calculations_use_input_precision =
+            pm.assume_16_bit_calculations = 0;
+
+      else if (strcmp(*argv, "--exhaustive") == 0)
+         pm.test_exhaustive = 1;
+
+      else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
+         --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
+
+      else if (argc > 1 && strcmp(*argv, "--touch") == 0)
+         --argc, touch = *++argv, catmore = 1;
+
+      else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
+      {
+         --argc;
+
+         if (strcmp(5+*argv, "abs8") == 0)
+            pm.maxabs8 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "abs16") == 0)
+            pm.maxabs16 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "calc8") == 0)
+            pm.maxcalc8 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "calc16") == 0)
+            pm.maxcalc16 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "out8") == 0)
+            pm.maxout8 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "out16") == 0)
+            pm.maxout16 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "pc8") == 0)
+            pm.maxpc8 = atof(*++argv);
+
+         else if (strcmp(5+*argv, "pc16") == 0)
+            pm.maxpc16 = atof(*++argv);
+
+         else
+         {
+            fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
+            exit(99);
+         }
+
+         catmore = 1;
+      }
+
+      else if (strcmp(*argv, "--log8") == 0)
+         --argc, pm.log8 = atof(*++argv), catmore = 1;
+
+      else if (strcmp(*argv, "--log16") == 0)
+         --argc, pm.log16 = atof(*++argv), catmore = 1;
+
+#ifdef PNG_SET_OPTION_SUPPORTED
+      else if (strncmp(*argv, "--option=", 9) == 0)
+      {
+         /* Syntax of the argument is <option>:{on|off} */
+         const char *arg = 9+*argv;
+         unsigned char option=0, setting=0;
+
+#ifdef PNG_ARM_NEON
+         if (strncmp(arg, "arm-neon:", 9) == 0)
+            option = PNG_ARM_NEON, arg += 9;
+
+         else
+#endif
+#ifdef PNG_EXTENSIONS
+         if (strncmp(arg, "extensions:", 11) == 0)
+            option = PNG_EXTENSIONS, arg += 11;
+
+         else
+#endif
+#ifdef PNG_MAXIMUM_INFLATE_WINDOW
+         if (strncmp(arg, "max-inflate-window:", 19) == 0)
+            option = PNG_MAXIMUM_INFLATE_WINDOW, arg += 19;
+
+         else
+#endif
+         {
+            fprintf(stderr, "pngvalid: %s: %s: unknown option\n", *argv, arg);
+            exit(99);
+         }
+
+         if (strcmp(arg, "off") == 0)
+            setting = PNG_OPTION_OFF;
+
+         else if (strcmp(arg, "on") == 0)
+            setting = PNG_OPTION_ON;
+
+         else
+         {
+            fprintf(stderr,
+               "pngvalid: %s: %s: unknown setting (use 'on' or 'off')\n",
+               *argv, arg);
+            exit(99);
+         }
+
+         pm.this.options[pm.this.noptions].option = option;
+         pm.this.options[pm.this.noptions++].setting = setting;
+      }
+#endif /* PNG_SET_OPTION_SUPPORTED */
+
+      else
+      {
+         fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
+         exit(99);
+      }
+
+      if (catmore) /* consumed an extra *argv */
+      {
+         cp = safecat(command, sizeof command, cp, " ");
+         cp = safecat(command, sizeof command, cp, *argv);
+      }
+   }
+
+   /* If pngvalid is run with no arguments default to a reasonable set of the
+    * tests.
+    */
+   if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
+      pm.ngamma_tests == 0)
+   {
+      /* Make this do all the tests done in the test shell scripts with the same
+       * parameters, where possible.  The limitation is that all the progressive
+       * read and interlace stuff has to be done in separate runs, so only the
+       * basic 'standard' and 'size' tests are done.
+       */
+      pm.test_standard = 1;
+      pm.test_size = 1;
+      pm.test_transform = 1;
+      pm.ngamma_tests = 2U;
+   }
+
+   if (pm.ngamma_tests > 0 &&
+      pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
+      pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
+      pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
+   {
+      pm.test_gamma_threshold = 1;
+      pm.test_gamma_transform = 1;
+      pm.test_gamma_sbit = 1;
+      pm.test_gamma_scale16 = 1;
+      pm.test_gamma_background = 1;
+      pm.test_gamma_alpha_mode = 1;
+   }
+
+   else if (pm.ngamma_tests == 0)
+   {
+      /* Nothing to test so turn everything off: */
+      pm.test_gamma_threshold = 0;
+      pm.test_gamma_transform = 0;
+      pm.test_gamma_sbit = 0;
+      pm.test_gamma_scale16 = 0;
+      pm.test_gamma_background = 0;
+      pm.test_gamma_alpha_mode = 0;
+   }
+
+   Try
+   {
+      /* Make useful base images */
+      make_transform_images(&pm);
+
+      /* Perform the standard and gamma tests. */
+      if (pm.test_standard)
+      {
+         perform_interlace_macro_validation();
+         perform_formatting_test(&pm.this);
+#        ifdef PNG_READ_SUPPORTED
+            perform_standard_test(&pm);
+#        endif
+         perform_error_test(&pm);
+      }
+
+      /* Various oddly sized images: */
+      if (pm.test_size)
+      {
+         make_size_images(&pm.this);
+#        ifdef PNG_READ_SUPPORTED
+            perform_size_test(&pm);
+#        endif
+      }
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+      /* Combinatorial transforms: */
+      if (pm.test_transform)
+         perform_transform_test(&pm);
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+      if (pm.ngamma_tests > 0)
+         perform_gamma_test(&pm, summary);
+#endif
+   }
+
+   Catch_anonymous
+   {
+      fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
+      if (!pm.this.verbose)
+      {
+         if (pm.this.error[0] != 0)
+            fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
+
+         fprintf(stderr, "pngvalid: run with -v to see what happened\n");
+      }
+      exit(1);
+   }
+
+   if (summary)
+   {
+      printf("%s: %s (%s point arithmetic)\n",
+         (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
+            pm.this.nwarnings)) ? "FAIL" : "PASS",
+         command,
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
+         "floating"
+#else
+         "fixed"
+#endif
+         );
+   }
+
+   if (memstats)
+   {
+      printf("Allocated memory statistics (in bytes):\n"
+         "\tread  %lu maximum single, %lu peak, %lu total\n"
+         "\twrite %lu maximum single, %lu peak, %lu total\n",
+         (unsigned long)pm.this.read_memory_pool.max_max,
+         (unsigned long)pm.this.read_memory_pool.max_limit,
+         (unsigned long)pm.this.read_memory_pool.max_total,
+         (unsigned long)pm.this.write_memory_pool.max_max,
+         (unsigned long)pm.this.write_memory_pool.max_limit,
+         (unsigned long)pm.this.write_memory_pool.max_total);
+   }
+
+   /* Do this here to provoke memory corruption errors in memory not directly
+    * allocated by libpng - not a complete test, but better than nothing.
+    */
+   store_delete(&pm.this);
+
+   /* Error exit if there are any errors, and maybe if there are any
+    * warnings.
+    */
+   if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
+       pm.this.nwarnings))
+   {
+      if (!pm.this.verbose)
+         fprintf(stderr, "pngvalid: %s\n", pm.this.error);
+
+      fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
+          pm.this.nwarnings);
+
+      exit(1);
+   }
+
+   /* Success case. */
+   if (touch != NULL)
+   {
+      FILE *fsuccess = fopen(touch, "wt");
+
+      if (fsuccess != NULL)
+      {
+         int error = 0;
+         fprintf(fsuccess, "PNG validation succeeded\n");
+         fflush(fsuccess);
+         error = ferror(fsuccess);
+
+         if (fclose(fsuccess) || error)
+         {
+            fprintf(stderr, "%s: write failed\n", touch);
+            exit(1);
+         }
+      }
+
+      else
+      {
+         fprintf(stderr, "%s: open failed\n", touch);
+         exit(1);
+      }
+   }
+
+   /* This is required because some very minimal configurations do not use it:
+    */
+   UNUSED(fail)
+   return 0;
+}
+#else /* write or low level APIs not supported */
+int main(void)
+{
+   fprintf(stderr,
+      "pngvalid: no low level write support in libpng, all tests skipped\n");
+   /* So the test is skipped: */
+   return SKIP;
+}
+#endif
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/readpng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/readpng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/readpng.c	(revision 107811)
@@ -0,0 +1,114 @@
+
+/* readpng.c
+ *
+ * Copyright (c) 2013 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Load an arbitrary number of PNG files (from the command line, or, if there
+ * are no arguments on the command line, from stdin) then run a time test by
+ * reading each file by row.  The test does nothing with the read result and
+ * does no transforms.  The only output is a time as a floating point number of
+ * seconds with 9 decimal digits.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+static int
+read_png(FILE *fp)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
+   png_infop info_ptr = NULL;
+   png_bytep row = NULL, display = NULL;
+
+   if (png_ptr == NULL)
+      return 0;
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      if (row != NULL) free(row);
+      if (display != NULL) free(display);
+      return 0;
+   }
+
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, NULL, 0);
+
+   png_read_info(png_ptr, info_ptr);
+
+   {
+      size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+      /* Failure to initialize these is harmless */
+      row = malloc(rowbytes);
+      display = malloc(rowbytes);
+
+      if (row == NULL || display == NULL)
+         png_error(png_ptr, "OOM allocating row buffers");
+
+      {
+         png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
+#        ifdef PNG_READ_INTERLACING_SUPPORTED
+            int passes = png_set_interlace_handling(png_ptr);
+#        else /* !READ_INTERLACING */
+            int passes = png_get_interlace_type(png_ptr, info_ptr) ==
+               PNG_INTERLACE_ADAM7 ? PNG_INTERLACE_ADAM7_PASSES : 1;
+#        endif /* !READ_INTERLACING */
+         int pass;
+
+         png_start_read_image(png_ptr);
+
+         for (pass = 0; pass < passes; ++pass)
+         {
+            png_uint_32 y = height;
+
+#           ifndef PNG_READ_INTERLACING_SUPPORTED
+               if (passes == PNG_INTERLACE_ADAM7_PASSES)
+                  y = PNG_PASS_ROWS(y, pass);
+#           endif /* READ_INTERLACING */
+
+            /* NOTE: this trashes the row each time; interlace handling won't
+             * work, but this avoids memory thrashing for speed testing.
+             */
+            while (y-- > 0)
+               png_read_row(png_ptr, row, display);
+         }
+      }
+   }
+
+   /* Make sure to read to the end of the file: */
+   png_read_end(png_ptr, info_ptr);
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   free(row);
+   free(display);
+   return 1;
+}
+
+int
+main(void)
+{
+   /* Exit code 0 on success. */
+   return !read_png(stdin);
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/tarith.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/tarith.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/tarith.c	(revision 107811)
@@ -0,0 +1,1011 @@
+
+/* tarith.c
+ *
+ * Copyright (c) 2021 Cosmin Truta
+ * Copyright (c) 2011-2013 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Test internal arithmetic functions of libpng.
+ *
+ * This code must be linked against a math library (-lm), but does not require
+ * libpng or zlib to work.  Because it includes the complete source of 'png.c'
+ * it tests the code with whatever compiler options are used to build it.
+ * Changing these options can substantially change the errors in the
+ * calculations that the compiler chooses!
+ */
+#define _POSIX_SOURCE 1
+#define _ISOC99_SOURCE 1
+
+/* Obtain a copy of the code to be tested (plus other things), disabling
+ * stuff that is not required.
+ */
+#include <math.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <assert.h>
+
+#include "../../pngpriv.h"
+
+#define png_error png_warning
+
+void png_warning(png_const_structrp png_ptr, png_const_charp msg)
+{
+   fprintf(stderr, "validation: %s\n", msg);
+}
+
+#define png_fixed_error png_fixed_warning
+
+void png_fixed_warning(png_const_structrp png_ptr, png_const_charp msg)
+{
+   fprintf(stderr, "overflow in: %s\n", msg);
+}
+
+#define png_set_error_fn(pp, ep, efp, wfp) ((void)0)
+#define png_malloc(pp, s) malloc(s)
+#define png_malloc_warn(pp, s) malloc(s)
+#define png_malloc_base(pp, s) malloc(s)
+#define png_calloc(pp, s) calloc(1, (s))
+#define png_free(pp, s) free(s)
+
+#define png_safecat(b, sb, pos, str) (pos)
+#define png_format_number(start, end, format, number) (start)
+
+#define crc32(crc, pp, s) (crc)
+#define inflateReset(zs) Z_OK
+
+#define png_create_struct(type) (0)
+#define png_destroy_struct(pp) ((void)0)
+#define png_create_struct_2(type, m, mm) (0)
+#define png_destroy_struct_2(pp, f, mm) ((void)0)
+
+#undef PNG_SIMPLIFIED_READ_SUPPORTED
+#undef PNG_SIMPLIFIED_WRITE_SUPPORTED
+#undef PNG_USER_MEM_SUPPORTED
+
+#include "../../png.c"
+
+/* Validate ASCII to fp routines. */
+static int verbose = 0;
+
+int validation_ascii_to_fp(int count, int argc, char **argv)
+{
+   int    showall = 0;
+   double max_error=2;      /* As a percentage error-in-last-digit/.5 */
+   double max_error_abs=17; /* Used when precision is DBL_DIG */
+   double max = 0;
+   double max_abs = 0;
+   double test = 0; /* Important to test this. */
+   int    precision = 5;
+   int    nonfinite = 0;
+   int    finite = 0;
+   int    ok = 0;
+   int    failcount = 0;
+   int    minorarith = 0;
+
+   while (--argc > 0)
+   {
+      if (strcmp(*++argv, "-a") == 0)
+         showall = 1;
+      else if (strcmp(*argv, "-e") == 0 && argc > 0)
+      {
+         --argc;
+         max_error = atof(*++argv);
+      }
+      else if (strcmp(*argv, "-E") == 0 && argc > 0)
+      {
+         --argc;
+         max_error_abs = atof(*++argv);
+      }
+      else
+      {
+         fprintf(stderr, "unknown argument %s\n", *argv);
+         return 1;
+      }
+   }
+
+   do
+   {
+      size_t index;
+      int state, failed = 0;
+      char buffer[64];
+
+      if (isfinite(test))
+         ++finite;
+      else
+         ++nonfinite;
+
+      if (verbose)
+         fprintf(stderr, "%.*g %d\n", DBL_DIG, test, precision);
+
+      /* Check for overflow in the buffer by setting a marker. */
+      memset(buffer, 71, sizeof buffer);
+
+      png_ascii_from_fp(0, buffer, precision+10, test, precision);
+
+      /* Allow for a three digit exponent, this stuff will fail if
+       * the exponent is bigger than this!
+       */
+      if (buffer[precision+7] != 71)
+      {
+         fprintf(stderr, "%g[%d] -> '%s'[%lu] buffer overflow\n",
+            test, precision, buffer, (unsigned long)strlen(buffer));
+         failed = 1;
+      }
+
+      /* Following are used for the number parser below and must be
+       * initialized to zero.
+       */
+      state = 0;
+      index = 0;
+      if (!isfinite(test))
+      {
+         /* Expect 'inf' */
+         if (test >= 0 && strcmp(buffer, "inf") ||
+             test <  0 && strcmp(buffer, "-inf"))
+         {
+            fprintf(stderr, "%g[%d] -> '%s' but expected 'inf'\n",
+               test, precision, buffer);
+            failed = 1;
+         }
+      }
+      else if (!png_check_fp_number(buffer, precision+10, &state, &index) ||
+          buffer[index] != 0)
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but has bad format ('%c')\n",
+            test, precision, buffer, buffer[index]);
+         failed = 1;
+      }
+      else if (PNG_FP_IS_NEGATIVE(state) && !(test < 0))
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but negative value not so reported\n",
+            test, precision, buffer);
+         failed = 1;
+         assert(!PNG_FP_IS_ZERO(state));
+         assert(!PNG_FP_IS_POSITIVE(state));
+      }
+      else if (PNG_FP_IS_ZERO(state) && !(test == 0))
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but zero value not so reported\n",
+            test, precision, buffer);
+         failed = 1;
+         assert(!PNG_FP_IS_NEGATIVE(state));
+         assert(!PNG_FP_IS_POSITIVE(state));
+      }
+      else if (PNG_FP_IS_POSITIVE(state) && !(test > 0))
+      {
+         fprintf(stderr, "%g[%d] -> '%s' but positive value not so reported\n",
+            test, precision, buffer);
+         failed = 1;
+         assert(!PNG_FP_IS_NEGATIVE(state));
+         assert(!PNG_FP_IS_ZERO(state));
+      }
+      else
+      {
+         /* Check the result against the original. */
+         double out = atof(buffer);
+         double change = fabs((out - test)/test);
+         double allow = .5 / pow(10,
+            (precision >= DBL_DIG) ? DBL_DIG-1 : precision-1);
+
+         /* NOTE: if you hit this error case are you compiling with gcc
+          * and -O0?  Try -O2 - the errors can accumulate if the FP
+          * code above is not optimized and may drift outside the .5 in
+          * DBL_DIG allowed.  In any case a small number of errors may
+          * occur (very small ones - 1 or 2%) because of rounding in the
+          * calculations, either in the conversion API or in atof.
+          */
+         if (change >= allow && (isfinite(out) ||
+             fabs(test/DBL_MAX) <= 1-allow))
+         {
+            double percent = (precision >= DBL_DIG) ? max_error_abs : max_error;
+            double allowp = (change-allow)*100/allow;
+
+            if (precision >= DBL_DIG)
+            {
+               if (max_abs < allowp) max_abs = allowp;
+            }
+
+            else
+            {
+               if (max < allowp) max = allowp;
+            }
+
+            if (showall || allowp >= percent)
+            {
+               fprintf(stderr,
+                  "%.*g[%d] -> '%s' -> %.*g number changed (%g > %g (%d%%))\n",
+                  DBL_DIG, test, precision, buffer, DBL_DIG, out, change, allow,
+                  (int)round(allowp));
+               failed = 1;
+            }
+            else
+               ++minorarith;
+         }
+      }
+
+      if (failed)
+         ++failcount;
+      else
+         ++ok;
+
+skip:
+      /* Generate a new number and precision. */
+      precision = rand();
+      if (precision & 1) test = -test;
+      precision >>= 1;
+
+      /* Generate random numbers. */
+      if (test == 0 || !isfinite(test))
+         test = precision+1;
+      else
+      {
+         /* Derive the exponent from the previous rand() value. */
+         int exponent = precision % (DBL_MAX_EXP - DBL_MIN_EXP) + DBL_MIN_EXP;
+         int tmp;
+         test = frexp(test * rand(), &tmp);
+         test = ldexp(test, exponent);
+         precision >>= 8; /* arbitrary */
+      }
+
+      /* This limits the precision to 32 digits, enough for standard
+       * IEEE implementations which have at most 15 digits.
+       */
+      precision = (precision & 0x1f) + 1;
+   }
+   while (--count);
+
+   printf("Tested %d finite values, %d non-finite, %d OK (%d failed) "
+      "%d minor arithmetic errors\n",
+      finite, nonfinite, ok, failcount, minorarith);
+   printf(" Error with >=%d digit precision %.2f%%\n", DBL_DIG, max_abs);
+   printf(" Error with < %d digit precision %.2f%%\n", DBL_DIG, max);
+
+   return 0;
+}
+
+/* Observe that valid FP numbers have the forms listed in the PNG extensions
+ * specification:
+ *
+ * [+,-]{integer,integer.fraction,.fraction}[{e,E}[+,-]integer]
+ *
+ * Test each of these in turn, including invalid cases.
+ */
+typedef enum checkfp_state
+{
+   start, fraction, exponent, states
+} checkfp_state;
+
+/* The characters (other than digits) that characterize the states: */
+static const char none[] = "";
+static const char hexdigits[16] = "0123456789ABCDEF";
+
+static const struct
+{
+   const char *start; /* Characters valid at the start */
+   const char *end;   /* Valid characters that end the state */
+   const char *tests; /* Characters to test after 2 digits seen */
+}
+state_characters[states] =
+{
+   /* start:    */ { "+-.", ".eE", "+-.e*0369" },
+   /* fraction: */ { none, "eE",  "+-.E#0147" },
+   /* exponent: */ { "+-", none,  "+-.eE^0258" }
+};
+
+typedef struct
+{
+   char number[1024];  /* Buffer for number being tested */
+   int  limit;         /* Command line limit */
+   int  verbose;       /* Shadows global variable */
+   int  ctimes;        /* Number of numbers tested */
+   int  cmillions;     /* Count of millions of numbers */
+   int  cinvalid;      /* Invalid strings checked */
+   int  cnoaccept;     /* Characters not accepted */
+}
+checkfp_command;
+
+typedef struct
+{
+   int           cnumber;          /* Index into number string */
+   checkfp_state check_state;      /* Current number state */
+   int           at_start;         /* At start (first character) of state */
+   int           cdigits_in_state; /* Digits seen in that state */
+   int           limit;            /* Limit on same for checking all chars */
+   int           state;            /* Current parser state */
+   int           is_negative;      /* Number is negative */
+   int           is_zero;          /* Number is (still) zero */
+   int           number_was_valid; /* Previous character validity */
+}
+checkfp_control;
+
+static int check_all_characters(checkfp_command *co, checkfp_control c);
+
+static int check_some_characters(checkfp_command *co, checkfp_control c,
+   const char *tests);
+
+static int check_one_character(checkfp_command *co, checkfp_control c, int ch)
+{
+   /* Test this character (ch) to ensure the parser does the correct thing.
+    */
+   size_t index = 0;
+   const char test = (char)ch;
+   int number_is_valid = png_check_fp_number(&test, 1, &c.state, &index);
+   int character_accepted = (index == 1);
+
+   if (c.check_state != exponent && isdigit(ch) && ch != '0')
+      c.is_zero = 0;
+
+   if (c.check_state == start && c.at_start && ch == '-')
+      c.is_negative = 1;
+
+   if (isprint(ch))
+      co->number[c.cnumber++] = (char)ch;
+   else
+   {
+      co->number[c.cnumber++] = '<';
+      co->number[c.cnumber++] = hexdigits[(ch >> 4) & 0xf];
+      co->number[c.cnumber++] = hexdigits[ch & 0xf];
+      co->number[c.cnumber++] = '>';
+   }
+   co->number[c.cnumber] = 0;
+
+   if (co->verbose > 1)
+      fprintf(stderr, "%s\n", co->number);
+
+   if (++(co->ctimes) == 1000000)
+   {
+      if (co->verbose == 1)
+         fputc('.', stderr);
+      co->ctimes = 0;
+      ++(co->cmillions);
+   }
+
+   if (!number_is_valid)
+      ++(co->cinvalid);
+
+   if (!character_accepted)
+      ++(co->cnoaccept);
+
+   /* This should never fail (it's a serious bug if it does): */
+   if (index != 0 && index != 1)
+   {
+      fprintf(stderr, "%s: read beyond end of string (%lu)\n",
+         co->number, (unsigned long)index);
+      return 0;
+   }
+
+   /* Validate the new state, note that the PNG_FP_IS_ macros all return
+    * false unless the number is valid.
+    */
+   if (PNG_FP_IS_NEGATIVE(c.state) !=
+      (number_is_valid && !c.is_zero && c.is_negative))
+   {
+      fprintf(stderr, "%s: negative when it is not\n", co->number);
+      return 0;
+   }
+
+   if (PNG_FP_IS_ZERO(c.state) != (number_is_valid && c.is_zero))
+   {
+      fprintf(stderr, "%s: zero when it is not\n", co->number);
+      return 0;
+   }
+
+   if (PNG_FP_IS_POSITIVE(c.state) !=
+      (number_is_valid && !c.is_zero && !c.is_negative))
+   {
+      fprintf(stderr, "%s: positive when it is not\n", co->number);
+      return 0;
+   }
+
+   /* Testing a digit */
+   if (isdigit(ch))
+   {
+      if (!character_accepted)
+      {
+         fprintf(stderr, "%s: digit '%c' not accepted\n", co->number, ch);
+         return 0;
+      }
+
+      if (!number_is_valid)
+      {
+         fprintf(stderr, "%s: saw a digit (%c) but number not valid\n",
+            co->number, ch);
+         return 0;
+      }
+
+      ++c.cdigits_in_state;
+      c.at_start = 0;
+      c.number_was_valid = 1;
+
+      /* Continue testing characters in this state.  Either test all of
+       * them or, if we have already seen one digit in this state, just test a
+       * limited set.
+       */
+      if (c.cdigits_in_state < 1)
+         return check_all_characters(co, c);
+
+      else
+         return check_some_characters(co, c,
+            state_characters[c.check_state].tests);
+   }
+
+   /* A non-digit; is it allowed here? */
+   else if (((ch == '+' || ch == '-') && c.check_state != fraction &&
+               c.at_start) ||
+            (ch == '.' && c.check_state == start) ||
+            ((ch == 'e' || ch == 'E') && c.number_was_valid &&
+               c.check_state != exponent))
+   {
+      if (!character_accepted)
+      {
+         fprintf(stderr, "%s: character '%c' not accepted\n", co->number, ch);
+         return 0;
+      }
+
+      /* The number remains valid after start of fraction but nowhere else. */
+      if (number_is_valid && (c.check_state != start || ch != '.'))
+      {
+         fprintf(stderr, "%s: saw a non-digit (%c) but number valid\n",
+            co->number, ch);
+         return 0;
+      }
+
+      c.number_was_valid = number_is_valid;
+
+      /* Check for a state change.  When changing to 'fraction' if the number
+       * is valid at this point set the at_start to false to allow an exponent
+       * 'e' to come next.
+       */
+      if (c.check_state == start && ch == '.')
+      {
+         c.check_state = fraction;
+         c.at_start = !number_is_valid;
+         c.cdigits_in_state = 0;
+         c.limit = co->limit;
+         return check_all_characters(co, c);
+      }
+
+      else if (c.check_state < exponent && (ch == 'e' || ch == 'E'))
+      {
+         c.check_state = exponent;
+         c.at_start = 1;
+         c.cdigits_in_state = 0;
+         c.limit = co->limit;
+         return check_all_characters(co, c);
+      }
+
+      /* Else it was a sign, and the state doesn't change. */
+      else
+      {
+         if (ch != '-' && ch != '+')
+         {
+            fprintf(stderr, "checkfp: internal error (1)\n");
+            return 0;
+         }
+
+         c.at_start = 0;
+         return check_all_characters(co, c);
+      }
+   }
+
+   /* Testing an invalid character */
+   else
+   {
+      if (character_accepted)
+      {
+         fprintf(stderr, "%s: character '%c' [0x%.2x] accepted\n", co->number,
+            ch, ch);
+         return 0;
+      }
+
+      if (number_is_valid != c.number_was_valid)
+      {
+         fprintf(stderr,
+            "%s: character '%c' [0x%.2x] changed number validity\n",
+            co->number, ch, ch);
+         return 0;
+      }
+
+      /* Do nothing - the parser has stuck; return success and keep going with
+       * the next character.
+       */
+   }
+
+   /* Successful return (the caller will try the next character.) */
+   return 1;
+}
+
+static int check_all_characters(checkfp_command *co, checkfp_control c)
+{
+   int ch;
+
+   if (c.cnumber+4 < sizeof co->number)
+   {
+      for (ch=0; ch<256; ++ch)
+      {
+         if (!check_one_character(co, c, ch))
+            return 0;
+      }
+   }
+
+   return 1;
+}
+
+static int check_some_characters(checkfp_command *co, checkfp_control c,
+   const char *tests)
+{
+   int i;
+
+   --(c.limit);
+
+   if (c.cnumber+4 < sizeof co->number && c.limit >= 0)
+   {
+      if (c.limit > 0)
+      {
+         for (i=0; tests[i]; ++i)
+         {
+            if (!check_one_character(co, c, tests[i]))
+                  return 0;
+         }
+      }
+
+      /* At the end check all the characters. */
+      else
+         return check_all_characters(co, c);
+   }
+
+   return 1;
+}
+
+int validation_checkfp(int count, int argc, char **argv)
+{
+   int result;
+   checkfp_command command;
+   checkfp_control control;
+
+   command.number[0] = 0;
+   command.limit = 3;
+   command.verbose = verbose;
+   command.ctimes = 0;
+   command.cmillions = 0;
+   command.cinvalid = 0;
+   command.cnoaccept = 0;
+
+   while (--argc > 0)
+   {
+      ++argv;
+      if (argc > 1 && strcmp(*argv, "-l") == 0)
+      {
+         --argc;
+         command.limit = atoi(*++argv);
+      }
+
+      else
+      {
+         fprintf(stderr, "unknown argument %s\n", *argv);
+         return 1;
+      }
+   }
+
+   control.cnumber = 0;
+   control.check_state = start;
+   control.at_start = 1;
+   control.cdigits_in_state = 0;
+   control.limit = command.limit;
+   control.state = 0;
+   control.is_negative = 0;
+   control.is_zero = 1;
+   control.number_was_valid = 0;
+
+   result = check_all_characters(&command, control);
+
+   printf("checkfp: %s: checked %d,%.3d,%.3d,%.3d strings (%d invalid)\n",
+      result ? "pass" : "FAIL", command.cmillions / 1000,
+      command.cmillions % 1000, command.ctimes / 1000, command.ctimes % 1000,
+      command.cinvalid);
+
+   return result;
+}
+
+int validation_muldiv(int count, int argc, char **argv)
+{
+   int tested = 0;
+   int overflow = 0;
+   int error = 0;
+   int error64 = 0;
+   int passed = 0;
+   int randbits = 0;
+   png_uint_32 randbuffer;
+   png_fixed_point a;
+   png_int_32 times, div;
+
+   while (--argc > 0)
+   {
+      fprintf(stderr, "unknown argument %s\n", *++argv);
+      return 1;
+   }
+
+   /* Find out about the random number generator. */
+   randbuffer = RAND_MAX;
+   while (randbuffer != 0) ++randbits, randbuffer >>= 1;
+   printf("Using random number generator that makes %d bits\n", randbits);
+   for (div=0; div<32; div += randbits)
+      randbuffer = (randbuffer << randbits) ^ rand();
+
+   a = 0;
+   times = div = 0;
+   do
+   {
+      png_fixed_point result;
+      /* NOTE: your mileage may vary, a type is required below that can
+       * hold 64 bits or more, if floating point is used a 64-bit or
+       * better mantissa is required.
+       */
+      long long int fp, fpround;
+      unsigned long hi, lo;
+      int ok;
+
+      /* Check the values, png_64bit_product can only handle positive
+       * numbers, so correct for that here.
+       */
+      {
+         long u1, u2;
+         int n = 0;
+         if (a < 0) u1 = -a, n = 1; else u1 = a;
+         if (times < 0) u2 = -times, n = !n; else u2 = times;
+         png_64bit_product(u1, u2, &hi, &lo);
+         if (n)
+         {
+            /* -x = ~x+1 */
+            lo = ((~lo) + 1) & 0xffffffff;
+            hi = ~hi;
+            if (lo == 0) ++hi;
+         }
+      }
+
+      fp = a;
+      fp *= times;
+      if ((fp & 0xffffffff) != lo || ((fp >> 32) & 0xffffffff) != hi)
+      {
+         fprintf(stderr, "png_64bit_product %d * %d -> %lx|%.8lx not %llx\n",
+            a, times, hi, lo, fp);
+         ++error64;
+      }
+
+      if (div != 0)
+      {
+         /* Round - this is C round to zero. */
+         if ((fp < 0) != (div < 0))
+           fp -= div/2;
+         else
+           fp += div/2;
+
+         fp /= div;
+         fpround = fp;
+         /* Assume 2's complement here: */
+         ok = fpround <= PNG_UINT_31_MAX &&
+              fpround >= -1-(long long int)PNG_UINT_31_MAX;
+         if (!ok) ++overflow;
+      }
+      else
+        ok = 0, ++overflow, fpround = fp/*misleading*/;
+
+      if (verbose)
+         fprintf(stderr, "TEST %d * %d / %d -> %lld (%s)\n",
+            a, times, div, fp, ok ? "ok" : "overflow");
+
+      ++tested;
+      if (png_muldiv(&result, a, times, div) != ok)
+      {
+         ++error;
+         if (ok)
+             fprintf(stderr, "%d * %d / %d -> overflow (expected %lld)\n",
+                a, times, div, fp);
+         else
+             fprintf(stderr, "%d * %d / %d -> %d (expected overflow %lld)\n",
+                a, times, div, result, fp);
+      }
+      else if (ok && result != fpround)
+      {
+         ++error;
+         fprintf(stderr, "%d * %d / %d -> %d not %lld\n",
+            a, times, div, result, fp);
+      }
+      else
+         ++passed;
+
+      /* Generate three new values, this uses rand() and rand() only returns
+       * up to RAND_MAX.
+       */
+      /* CRUDE */
+      a += times;
+      times += div;
+      div = randbuffer;
+      randbuffer = (randbuffer << randbits) ^ rand();
+   }
+   while (--count > 0);
+
+   printf("%d tests including %d overflows, %d passed, %d failed "
+      "(%d 64-bit errors)\n", tested, overflow, passed, error, error64);
+   return 0;
+}
+
+/* When FP is on this just becomes a speed test - compile without FP to get real
+ * validation.
+ */
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+#define LN2 .000010576586617430806112933839 /* log(2)/65536 */
+#define L2INV 94548.46219969910586572651    /* 65536/log(2) */
+
+/* For speed testing, need the internal functions too: */
+static png_uint_32 png_log8bit(unsigned x)
+{
+   if (x > 0)
+      return (png_uint_32)floor(.5-log(x/255.)*L2INV);
+
+   return 0xffffffff;
+}
+
+static png_uint_32 png_log16bit(png_uint_32 x)
+{
+   if (x > 0)
+      return (png_uint_32)floor(.5-log(x/65535.)*L2INV);
+
+   return 0xffffffff;
+}
+
+static png_uint_32 png_exp(png_uint_32 x)
+{
+   return (png_uint_32)floor(.5 + exp(x * -LN2) * 0xffffffffU);
+}
+
+static png_byte png_exp8bit(png_uint_32 log)
+{
+   return (png_byte)floor(.5 + exp(log * -LN2) * 255);
+}
+
+static png_uint_16 png_exp16bit(png_uint_32 log)
+{
+   return (png_uint_16)floor(.5 + exp(log * -LN2) * 65535);
+}
+#endif /* FLOATING_ARITHMETIC */
+
+int validation_gamma(int argc, char **argv)
+{
+   double gamma[9] = { 2.2, 1.8, 1.52, 1.45, 1., 1/1.45, 1/1.52, 1/1.8, 1/2.2 };
+   double maxerr;
+   int i, silent=0, onlygamma=0;
+
+   /* Silence the output with -s, just test the gamma functions with -g: */
+   while (--argc > 0)
+      if (strcmp(*++argv, "-s") == 0)
+         silent = 1;
+      else if (strcmp(*argv, "-g") == 0)
+         onlygamma = 1;
+      else
+      {
+         fprintf(stderr, "unknown argument %s\n", *argv);
+         return 1;
+      }
+
+   if (!onlygamma)
+   {
+      /* First validate the log functions: */
+      maxerr = 0;
+      for (i=0; i<256; ++i)
+      {
+         double correct = -log(i/255.)/log(2.)*65536;
+         double error = png_log8bit(i) - correct;
+
+         if (i != 0 && fabs(error) > maxerr)
+            maxerr = fabs(error);
+
+         if (i == 0 && png_log8bit(i) != 0xffffffff ||
+             i != 0 && png_log8bit(i) != floor(correct+.5))
+         {
+            fprintf(stderr, "8-bit log error: %d: got %u, expected %f\n",
+               i, png_log8bit(i), correct);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 8-bit log error = %f\n", maxerr);
+
+      maxerr = 0;
+      for (i=0; i<65536; ++i)
+      {
+         double correct = -log(i/65535.)/log(2.)*65536;
+         double error = png_log16bit(i) - correct;
+
+         if (i != 0 && fabs(error) > maxerr)
+            maxerr = fabs(error);
+
+         if (i == 0 && png_log16bit(i) != 0xffffffff ||
+             i != 0 && png_log16bit(i) != floor(correct+.5))
+         {
+            if (error > .68) /* By experiment error is less than .68 */
+            {
+               fprintf(stderr,
+                  "16-bit log error: %d: got %u, expected %f error: %f\n",
+                  i, png_log16bit(i), correct, error);
+            }
+         }
+      }
+
+      if (!silent)
+         printf("maximum 16-bit log error = %f\n", maxerr);
+
+      /* Now exponentiations. */
+      maxerr = 0;
+      for (i=0; i<=0xfffff; ++i)
+      {
+         double correct = exp(-i/65536. * log(2.)) * (65536. * 65536);
+         double error = png_exp(i) - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > 1883) /* By experiment. */
+         {
+            fprintf(stderr,
+               "32-bit exp error: %d: got %u, expected %f error: %f\n",
+               i, png_exp(i), correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 32-bit exp error = %f\n", maxerr);
+
+      maxerr = 0;
+      for (i=0; i<=0xfffff; ++i)
+      {
+         double correct = exp(-i/65536. * log(2.)) * 255;
+         double error = png_exp8bit(i) - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > .50002) /* By experiment */
+         {
+            fprintf(stderr,
+               "8-bit exp error: %d: got %u, expected %f error: %f\n",
+               i, png_exp8bit(i), correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 8-bit exp error = %f\n", maxerr);
+
+      maxerr = 0;
+      for (i=0; i<=0xfffff; ++i)
+      {
+         double correct = exp(-i/65536. * log(2.)) * 65535;
+         double error = png_exp16bit(i) - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > .524) /* By experiment */
+         {
+            fprintf(stderr,
+               "16-bit exp error: %d: got %u, expected %f error: %f\n",
+               i, png_exp16bit(i), correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("maximum 16-bit exp error = %f\n", maxerr);
+   } /* !onlygamma */
+
+   /* Test the overall gamma correction. */
+   for (i=0; i<9; ++i)
+   {
+      unsigned j;
+      double g = gamma[i];
+      png_fixed_point gfp = floor(g * PNG_FP_1 + .5);
+
+      if (!silent)
+         printf("Test gamma %f\n", g);
+
+      maxerr = 0;
+      for (j=0; j<256; ++j)
+      {
+         double correct = pow(j/255., g) * 255;
+         png_byte out = png_gamma_8bit_correct(j, gfp);
+         double error = out - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (out != floor(correct+.5))
+         {
+            fprintf(stderr, "8bit %d ^ %f: got %d expected %f error %f\n",
+               j, g, out, correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("gamma %f: maximum 8-bit error %f\n", g, maxerr);
+
+      maxerr = 0;
+      for (j=0; j<65536; ++j)
+      {
+         double correct = pow(j/65535., g) * 65535;
+         png_uint_16 out = png_gamma_16bit_correct(j, gfp);
+         double error = out - correct;
+
+         if (fabs(error) > maxerr)
+            maxerr = fabs(error);
+         if (fabs(error) > 1.62)
+         {
+            fprintf(stderr, "16bit %d ^ %f: got %d expected %f error %f\n",
+               j, g, out, correct, error);
+         }
+      }
+
+      if (!silent)
+         printf("gamma %f: maximum 16-bit error %f\n", g, maxerr);
+   }
+
+   return 0;
+}
+
+/**************************** VALIDATION TESTS ********************************/
+/* Various validation routines are included herein, they require some
+ * definition for png_warning and png_error, settings of VALIDATION:
+ *
+ * 1: validates the ASCII to floating point conversions
+ * 2: validates png_muldiv
+ * 3: accuracy test of fixed point gamma tables
+ */
+
+/* The following COUNT (10^8) takes about 1 hour on a 1GHz Pentium IV
+ * processor.
+ */
+#define COUNT 1000000000
+
+int main(int argc, char **argv)
+{
+   int count = COUNT;
+
+   while (argc > 1)
+   {
+      if (argc > 2 && strcmp(argv[1], "-c") == 0)
+      {
+         count = atoi(argv[2]);
+         argc -= 2;
+         argv += 2;
+      }
+
+      else if (strcmp(argv[1], "-v") == 0)
+      {
+         ++verbose;
+         --argc;
+         ++argv;
+      }
+
+      else
+         break;
+   }
+
+   if (count > 0 && argc > 1)
+   {
+      if (strcmp(argv[1], "ascii") == 0)
+         return validation_ascii_to_fp(count, argc-1, argv+1);
+      else if (strcmp(argv[1], "checkfp") == 0)
+         return validation_checkfp(count, argc-1, argv+1);
+      else if (strcmp(argv[1], "muldiv") == 0)
+         return validation_muldiv(count, argc-1, argv+1);
+      else if (strcmp(argv[1], "gamma") == 0)
+         return validation_gamma(argc-1, argv+1);
+   }
+
+   /* Bad argument: */
+   fprintf(stderr,
+      "usage: tarith [-v] [-c count] {ascii,muldiv,gamma} [args]\n");
+   fprintf(stderr, " arguments: ascii [-a (all results)] [-e error%%]\n");
+   fprintf(stderr, "            checkfp [-l max-number-chars]\n");
+   fprintf(stderr, "            muldiv\n");
+   fprintf(stderr, "            gamma -s (silent) -g (only gamma; no log)\n");
+   return 1;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/libtests/timepng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/libtests/timepng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/libtests/timepng.c	(revision 107811)
@@ -0,0 +1,607 @@
+
+/* timepng.c
+ *
+ * Copyright (c) 2013,2016 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Load an arbitrary number of PNG files (from the command line, or, if there
+ * are no arguments on the command line, from stdin) then run a time test by
+ * reading each file by row or by image (possibly with transforms in the latter
+ * case).  The only output is a time as a floating point number of seconds with
+ * 9 decimal digits.
+ */
+#define _POSIX_C_SOURCE 199309L /* for clock_gettime */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+
+#include <time.h>
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+/* The following is to support direct compilation of this file as C++ */
+#ifdef __cplusplus
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+/* 'CLOCK_PROCESS_CPUTIME_ID' is one of the clock timers for clock_gettime.  It
+ * need not be supported even when clock_gettime is available.  It returns the
+ * 'CPU' time the process has consumed.  'CPU' time is assumed to include time
+ * when the CPU is actually blocked by a pending cache fill but not time
+ * waiting for page faults.  The attempt is to get a measure of the actual time
+ * the implementation takes to read a PNG ignoring the potentially very large IO
+ * overhead.
+ */
+#if defined (CLOCK_PROCESS_CPUTIME_ID) && defined(PNG_STDIO_SUPPORTED) &&\
+    defined(PNG_EASY_ACCESS_SUPPORTED) &&\
+    (PNG_LIBPNG_VER >= 10700 ? defined(PNG_READ_PNG_SUPPORTED) :\
+     defined (PNG_SEQUENTIAL_READ_SUPPORTED) &&\
+     defined(PNG_INFO_IMAGE_SUPPORTED))
+
+typedef struct
+{
+   FILE *input;
+   FILE *output;
+}  io_data;
+
+static PNG_CALLBACK(void, read_and_copy,
+      (png_structp png_ptr, png_bytep buffer, size_t cb))
+{
+   io_data *io = (io_data*)png_get_io_ptr(png_ptr);
+
+   if (fread(buffer, cb, 1, io->input) != 1)
+      png_error(png_ptr, strerror(errno));
+
+   if (fwrite(buffer, cb, 1, io->output) != 1)
+   {
+      perror("temporary file");
+      fprintf(stderr, "temporary file PNG write failed\n");
+      exit(1);
+   }
+}
+
+static void read_by_row(png_structp png_ptr, png_infop info_ptr,
+      FILE *write_ptr, FILE *read_ptr)
+{
+   /* These don't get freed on error, this is fine; the program immediately
+    * exits.
+    */
+   png_bytep row = NULL, display = NULL;
+   io_data io_copy;
+
+   if (write_ptr != NULL)
+   {
+      /* Set up for a copy to the temporary file: */
+      io_copy.input = read_ptr;
+      io_copy.output = write_ptr;
+      png_set_read_fn(png_ptr, &io_copy, read_and_copy);
+   }
+
+   png_read_info(png_ptr, info_ptr);
+
+   {
+      size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+      row = voidcast(png_bytep,malloc(rowbytes));
+      display = voidcast(png_bytep,malloc(rowbytes));
+
+      if (row == NULL || display == NULL)
+         png_error(png_ptr, "OOM allocating row buffers");
+
+      {
+         png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
+         int passes = png_set_interlace_handling(png_ptr);
+         int pass;
+
+         png_start_read_image(png_ptr);
+
+         for (pass = 0; pass < passes; ++pass)
+         {
+            png_uint_32 y = height;
+
+            /* NOTE: this trashes the row each time; interlace handling won't
+             * work, but this avoids memory thrashing for speed testing and is
+             * somewhat representative of an application that works row-by-row.
+             */
+            while (y-- > 0)
+               png_read_row(png_ptr, row, display);
+         }
+      }
+   }
+
+   /* Make sure to read to the end of the file: */
+   png_read_end(png_ptr, info_ptr);
+
+   /* Free this up: */
+   free(row);
+   free(display);
+}
+
+static PNG_CALLBACK(void, no_warnings, (png_structp png_ptr,
+         png_const_charp warning))
+{
+   (void)png_ptr;
+   (void)warning;
+}
+
+static int read_png(FILE *fp, png_int_32 transforms, FILE *write_file)
+{
+   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,
+         no_warnings);
+   png_infop info_ptr = NULL;
+
+   if (png_ptr == NULL)
+      return 0;
+
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      return 0;
+   }
+
+#  ifdef PNG_BENIGN_ERRORS_SUPPORTED
+      png_set_benign_errors(png_ptr, 1/*allowed*/);
+#  endif
+   png_init_io(png_ptr, fp);
+
+   info_ptr = png_create_info_struct(png_ptr);
+
+   if (info_ptr == NULL)
+      png_error(png_ptr, "OOM allocating info structure");
+
+   if (transforms < 0)
+      read_by_row(png_ptr, info_ptr, write_file, fp);
+
+   else
+      png_read_png(png_ptr, info_ptr, transforms, NULL/*params*/);
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   return 1;
+}
+
+static int mytime(struct timespec *t)
+{
+   /* Do the timing using clock_gettime and the per-process timer. */
+   if (!clock_gettime(CLOCK_PROCESS_CPUTIME_ID, t))
+      return 1;
+
+   perror("CLOCK_PROCESS_CPUTIME_ID");
+   fprintf(stderr, "timepng: could not get the time\n");
+   return 0;
+}
+
+static int perform_one_test(FILE *fp, int nfiles, png_int_32 transforms)
+{
+   int i;
+   struct timespec before, after;
+
+   /* Clear out all errors: */
+   rewind(fp);
+
+   if (mytime(&before))
+   {
+      for (i=0; i<nfiles; ++i)
+      {
+         if (read_png(fp, transforms, NULL/*write*/))
+         {
+            if (ferror(fp))
+            {
+               perror("temporary file");
+               fprintf(stderr, "file %d: error reading PNG data\n", i);
+               return 0;
+            }
+         }
+
+         else
+         {
+            perror("temporary file");
+            fprintf(stderr, "file %d: error from libpng\n", i);
+            return 0;
+         }
+      }
+   }
+
+   else
+      return 0;
+
+   if (mytime(&after))
+   {
+      /* Work out the time difference and print it - this is the only output,
+       * so flush it immediately.
+       */
+      unsigned long s = after.tv_sec - before.tv_sec;
+      long ns = after.tv_nsec - before.tv_nsec;
+
+      if (ns < 0)
+      {
+         --s;
+         ns += 1000000000;
+
+         if (ns < 0)
+         {
+            fprintf(stderr, "timepng: bad clock from kernel\n");
+            return 0;
+         }
+      }
+
+      printf("%lu.%.9ld\n", s, ns);
+      fflush(stdout);
+      if (ferror(stdout))
+      {
+         fprintf(stderr, "timepng: error writing output\n");
+         return 0;
+      }
+
+      /* Successful return */
+      return 1;
+   }
+
+   else
+      return 0;
+}
+
+static int add_one_file(FILE *fp, char *name)
+{
+   FILE *ip = fopen(name, "rb");
+
+   if (ip != NULL)
+   {
+      /* Read the file using libpng; this detects errors and also deals with
+       * files which contain data beyond the end of the file.
+       */
+      int ok = 0;
+      fpos_t pos;
+
+      if (fgetpos(fp, &pos))
+      {
+         /* Fatal error reading the start: */
+         perror("temporary file");
+         fprintf(stderr, "temporary file fgetpos error\n");
+         exit(1);
+      }
+
+      if (read_png(ip, -1/*by row*/, fp/*output*/))
+      {
+         if (ferror(ip))
+         {
+            perror(name);
+            fprintf(stderr, "%s: read error\n", name);
+         }
+
+         else
+            ok = 1; /* read ok */
+      }
+
+      else
+         fprintf(stderr, "%s: file not added\n", name);
+
+      (void)fclose(ip);
+
+      /* An error in the output is fatal; exit immediately: */
+      if (ferror(fp))
+      {
+         perror("temporary file");
+         fprintf(stderr, "temporary file write error\n");
+         exit(1);
+      }
+
+      if (ok)
+         return 1;
+
+      /* Did not read the file successfully, simply rewind the temporary
+       * file.  This must happen after the ferror check above to avoid clearing
+       * the error.
+       */
+      if (fsetpos(fp, &pos))
+      {
+         perror("temporary file");
+         fprintf(stderr, "temporary file fsetpos error\n");
+         exit(1);
+      }
+   }
+
+   else
+   {
+      /* file open error: */
+      perror(name);
+      fprintf(stderr, "%s: open failed\n", name);
+   }
+
+   return 0; /* file not added */
+}
+
+static void
+usage(FILE *fp)
+{
+   if (fp != NULL) fclose(fp);
+
+   fprintf(stderr,
+"Usage:\n"
+" timepng --assemble <assembly> {files}\n"
+"  Read the files into <assembly>, output the count.  Options are ignored.\n"
+" timepng --dissemble <assembly> <count> [options]\n"
+"  Time <count> files from <assembly>, additional files may not be given.\n"
+" Otherwise:\n"
+"  Read the files into a temporary file and time the decode\n"
+"Transforms:\n"
+"  --by-image: read by image with png_read_png\n"
+"  --<transform>: implies by-image, use PNG_TRANSFORM_<transform>\n"
+"  Otherwise: read by row using png_read_row (to a single row buffer)\n"
+   /* ISO C90 string length max 509 */);fprintf(stderr,
+"{files}:\n"
+"  PNG files to copy into the assembly and time.  Invalid files are skipped\n"
+"  with appropriate error messages.  If no files are given the list of files\n"
+"  is read from stdin with each file name terminated by a newline\n"
+"Output:\n"
+"  For --assemble the output is the name of the assembly file followed by the\n"
+"  count of the files it contains; the arguments for --dissemble.  Otherwise\n"
+"  the output is the total decode time in seconds.\n");
+
+   exit(99);
+}
+
+int main(int argc, char **argv)
+{
+   int ok = 0;
+   int err = 0;
+   int nfiles = 0;
+   int transforms = -1; /* by row */
+   const char *assembly = NULL;
+   FILE *fp;
+
+   if (argc > 2 && strcmp(argv[1], "--assemble") == 0)
+   {
+      /* Just build the test file, argv[2] is the file name. */
+      assembly = argv[2];
+      fp = fopen(assembly, "wb");
+      if (fp == NULL)
+      {
+         perror(assembly);
+         fprintf(stderr, "timepng --assemble %s: could not open for write\n",
+               assembly);
+         usage(NULL);
+      }
+
+      argv += 2;
+      argc -= 2;
+   }
+
+   else if (argc > 3 && strcmp(argv[1], "--dissemble") == 0)
+   {
+      fp = fopen(argv[2], "rb");
+
+      if (fp == NULL)
+      {
+         perror(argv[2]);
+         fprintf(stderr, "timepng --dissemble %s: could not open for read\n",
+               argv[2]);
+         usage(NULL);
+      }
+
+      nfiles = atoi(argv[3]);
+      if (nfiles <= 0)
+      {
+         fprintf(stderr,
+               "timepng --dissemble <file> <count>: %s is not a count\n",
+               argv[3]);
+         exit(99);
+      }
+#ifdef __COVERITY__
+      else
+      {
+         nfiles &= PNG_UINT_31_MAX;
+      }
+#endif
+
+      argv += 3;
+      argc -= 3;
+   }
+
+   else /* Else use a temporary file */
+   {
+#ifndef __COVERITY__
+      fp = tmpfile();
+#else
+      /* Experimental. Coverity says tmpfile() is insecure because it
+       * generates predictable names.
+       *
+       * It is possible to satisfy Coverity by using mkstemp(); however,
+       * any platform supporting mkstemp() undoubtedly has a secure tmpfile()
+       * implementation as well, and doesn't need the fix.  Note that
+       * the fix won't work on platforms that don't support mkstemp().
+       *
+       * https://www.securecoding.cert.org/confluence/display/c/
+       * FIO21-C.+Do+not+create+temporary+files+in+shared+directories
+       * says that most historic implementations of tmpfile() provide
+       * only a limited number of possible temporary file names
+       * (usually 26) before file names are recycled. That article also
+       * provides a secure solution that unfortunately depends upon mkstemp().
+       */
+      char tmpfile[] = "timepng-XXXXXX";
+      int filedes;
+      umask(0177);
+      filedes = mkstemp(tmpfile);
+      if (filedes < 0)
+        fp = NULL;
+      else
+      {
+        fp = fdopen(filedes,"w+");
+        /* Hide the filename immediately and ensure that the file does
+         * not exist after the program ends
+         */
+        (void) unlink(tmpfile);
+      }
+#endif
+
+      if (fp == NULL)
+      {
+         perror("tmpfile");
+         fprintf(stderr, "timepng: could not open the temporary file\n");
+         exit(1); /* not a user error */
+      }
+   }
+
+   /* Handle the transforms: */
+   while (argc > 1 && argv[1][0] == '-' && argv[1][1] == '-')
+   {
+      const char *opt = *++argv + 2;
+
+      --argc;
+
+      /* Transforms turn on the by-image processing and maybe set some
+       * transforms:
+       */
+      if (transforms == -1)
+         transforms = PNG_TRANSFORM_IDENTITY;
+
+      if (strcmp(opt, "by-image") == 0)
+      {
+         /* handled above */
+      }
+
+#        define OPT(name) else if (strcmp(opt, #name) == 0)\
+         transforms |= PNG_TRANSFORM_ ## name
+
+      OPT(STRIP_16);
+      OPT(STRIP_ALPHA);
+      OPT(PACKING);
+      OPT(PACKSWAP);
+      OPT(EXPAND);
+      OPT(INVERT_MONO);
+      OPT(SHIFT);
+      OPT(BGR);
+      OPT(SWAP_ALPHA);
+      OPT(SWAP_ENDIAN);
+      OPT(INVERT_ALPHA);
+      OPT(STRIP_FILLER);
+      OPT(STRIP_FILLER_BEFORE);
+      OPT(STRIP_FILLER_AFTER);
+      OPT(GRAY_TO_RGB);
+      OPT(EXPAND_16);
+      OPT(SCALE_16);
+
+      else
+      {
+         fprintf(stderr, "timepng %s: unrecognized transform\n", opt);
+         usage(fp);
+      }
+   }
+
+   /* Handle the files: */
+   if (argc > 1 && nfiles > 0)
+      usage(fp); /* Additional files not valid with --dissemble */
+
+   else if (argc > 1)
+   {
+      int i;
+
+      for (i=1; i<argc; ++i)
+      {
+         if (nfiles == INT_MAX)
+         {
+            fprintf(stderr, "%s: skipped, too many files\n", argv[i]);
+            break;
+         }
+
+         else if (add_one_file(fp, argv[i]))
+            ++nfiles;
+      }
+   }
+
+   else if (nfiles == 0) /* Read from stdin without --dissemble */
+   {
+      char filename[FILENAME_MAX+1];
+
+      while (fgets(filename, FILENAME_MAX+1, stdin))
+      {
+         size_t len = strlen(filename);
+
+         if (filename[len-1] == '\n')
+         {
+            filename[len-1] = 0;
+            if (nfiles == INT_MAX)
+            {
+               fprintf(stderr, "%s: skipped, too many files\n", filename);
+               break;
+            }
+
+            else if (add_one_file(fp, filename))
+               ++nfiles;
+         }
+
+         else
+         {
+            fprintf(stderr, "timepng: file name too long: ...%s\n",
+               filename+len-32);
+            err = 1;
+            break;
+         }
+      }
+
+      if (ferror(stdin))
+      {
+         fprintf(stderr, "timepng: stdin: read error\n");
+         err = 1;
+      }
+   }
+
+   /* Perform the test, or produce the --assemble output: */
+   if (!err)
+   {
+      if (nfiles > 0)
+      {
+         if (assembly != NULL)
+         {
+            if (fflush(fp) && !ferror(fp) && fclose(fp))
+            {
+               perror(assembly);
+               fprintf(stderr, "%s: close failed\n", assembly);
+            }
+
+            else
+            {
+               printf("%s %d\n", assembly, nfiles);
+               fflush(stdout);
+               ok = !ferror(stdout);
+            }
+         }
+
+         else
+         {
+            ok = perform_one_test(fp, nfiles, transforms);
+            (void)fclose(fp);
+         }
+      }
+
+      else
+         usage(fp);
+   }
+
+   else
+      (void)fclose(fp);
+
+   /* Exit code 0 on success. */
+   return ok == 0;
+}
+#else /* !sufficient support */
+int main(void) { return 77; }
+#endif /* !sufficient support */
Index: /trunk/src/libs/libpng-1.6.45/contrib/mips-msa/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/mips-msa/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/mips-msa/README	(revision 107811)
@@ -0,0 +1,83 @@
+OPERATING SYSTEM SPECIFIC MIPS MSA DETECTION
+--------------------------------------------
+
+Detection of the ability to execute MIPS MSA on an MIPS processor requires
+operating system support.  (The information is not available in user mode.)
+
+HOW TO USE THIS
+---------------
+
+This directory contains C code fragments that can be included in mips/mips_init.c
+by setting the macro PNG_MIPS_MSA_FILE to the file name in "" or <> at build
+time.  This setting is not recorded in pnglibconf.h and can be changed simply by
+rebuilding mips/msa_init.o with the required macro definition.
+
+For any of this code to be used the MIPS MSA code must be enabled and run time
+checks must be supported.  I.e.:
+
+#if PNG_MIPS_MSA_OPT > 0
+#ifdef PNG_MIPS_MSA_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-mips-msa=check
+
+Apart from the basic Linux implementation in contrib/mips-msa/linux.c this code
+is unsupported.  That means that it is not even compiled on a regular basis and
+may be broken in any given minor release.
+
+FILE FORMAT
+-----------
+
+Each file documents its testing status as of the last time it was tested (which
+may have been a long time ago):
+
+STATUS: one of:
+   SUPPORTED: This indicates that the file is included in the regularly
+         performed test builds and bugs are fixed when discovered.
+   COMPILED: This indicates that the code did compile at least once.  See the
+         more detailed description for the extent to which the result was
+         successful.
+   TESTED: This means the code was fully compiled into the libpng test programs
+         and these were run at least once.
+
+BUG REPORTS: an email address to which to send reports of problems
+
+The file is a fragment of C code. It should not define any 'extern' symbols;
+everything should be static.  It must define the function:
+
+static int png_have_msa(png_structp png_ptr);
+
+That function must return 1 if MIPS MSA instructions are supported, 0 if not.
+It must not execute png_error unless it detects a bug.  A png_error will prevent
+the reading of the PNG and in the future, writing too.
+
+BUG REPORTS
+-----------
+
+If you mail a bug report for any file that is not SUPPORTED there may only be
+limited response.  Consider fixing it and sending a patch to fix the problem -
+this is more likely to result in action.
+
+CONTRIBUTIONS
+-------------
+
+You may send contributions of new implementations to
+png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+possible.  Obviously OS dependencies are to be expected.  If you submit code you
+must have the authors permission and it must have a license that is acceptable
+to the current maintainer; in particular that license must permit modification
+and redistribution.
+
+Please try to make the contribution a single file and give the file a clear and
+unambiguous name that identifies the target OS.  If multiple files really are
+required put them all in a sub-directory.
+
+You must also be prepared to handle bug reports from users of the code, either
+by joining the png-mng-implement mailing list or by providing an email for the
+"BUG REPORTS" entry or both.  Please make sure that the header of the file
+contains the STATUS and BUG REPORTS fields as above.
+
+Please list the OS requirements as precisely as possible.  Ideally you should
+also list the environment in which the code has been tested and certainly list
+any environments where you suspect it might not work.
Index: /trunk/src/libs/libpng-1.6.45/contrib/mips-msa/linux.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/mips-msa/linux.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/mips-msa/linux.c	(revision 107811)
@@ -0,0 +1,55 @@
+
+/* contrib/mips-msa/linux.c
+ *
+ * Copyright (c) 2020-2023 Cosmin Truta
+ * Copyright (c) 2016 Glenn Randers-Pehrson
+ * Written by Mandar Sahastrabuddhe, 2016.
+ * Updated by Sui Jingfeng, 2021.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * On Linux, png_have_msa is implemented by reading the pseudo-file
+ * "/proc/self/auxv".
+ *
+ * See contrib/mips-msa/README before reporting bugs.
+ *
+ * STATUS: SUPPORTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ */
+
+#include <elf.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static int
+png_have_msa(png_structp png_ptr)
+{
+   Elf64_auxv_t aux;
+   int fd;
+   int has_msa = 0;
+
+   fd = open("/proc/self/auxv", O_RDONLY);
+   if (fd >= 0)
+   {
+      while (read(fd, &aux, sizeof(Elf64_auxv_t)) == sizeof(Elf64_auxv_t))
+      {
+         if (aux.a_type == AT_HWCAP)
+         {
+            uint64_t hwcap = aux.a_un.a_val;
+
+            has_msa = (hwcap >> 1) & 1;
+            break;
+         }
+      }
+      close(fd);
+   }
+#ifdef PNG_WARNINGS_SUPPORTED
+   else
+      png_warning(png_ptr, "/proc/self/auxv open failed");
+#endif
+
+   return has_msa;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/Dockerfile
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/Dockerfile	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/Dockerfile	(revision 107811)
@@ -0,0 +1,25 @@
+# Copyright 2016 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+################################################################################
+
+FROM gcr.io/oss-fuzz-base/base-builder
+MAINTAINER glennrp@gmail.com
+RUN apt-get update && \
+    apt-get install -y make autoconf automake libtool
+
+RUN git clone --depth 1 https://github.com/madler/zlib.git
+RUN git clone --depth 1 https://github.com/glennrp/libpng.git
+RUN cp libpng/contrib/oss-fuzz/build.sh $SRC
+WORKDIR libpng
Index: /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/README.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/README.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/README.txt	(revision 107811)
@@ -0,0 +1,36 @@
+Copyright (c) 2017 Glenn Randers-Pehrson
+
+This code is released under the libpng license.
+For conditions of distribution and use, see the disclaimer
+and license in png.h
+
+Files in this directory are used by the oss-fuzz project
+(https://github.com/google/oss-fuzz/tree/master/projects/libpng).
+for "fuzzing" libpng.
+
+They were licensed by Google Inc, using the BSD-like Chromium license,
+which may be found at https://cs.chromium.org/chromium/src/LICENSE, or, if
+noted in the source, under the Apache-2.0 license, which may
+be found at http://www.apache.org/licenses/LICENSE-2.0 .
+If they have been modified, the derivatives are copyright Glenn Randers-Pehrson
+and are released under the same licenses as the originals.  Several of
+the original files (libpng_read_fuzzer.options, png.dict, project.yaml)
+had no licensing information; we assumed that these were under the Chromium
+license. Any new files are released under the libpng license (see png.h).
+
+The files are
+                            Original
+ Filename                   or derived   Copyright          License
+ =========================  ==========   ================   ==========
+ Dockerfile*                derived      2017, Glenn R-P    Apache 2.0
+ build.sh                   derived      2017, Glenn R-P    Apache 2.0
+ libpng_read_fuzzer.cc      derived      2017, Glenn R-P    Chromium
+ libpng_read_fuzzer.options original     2015, Chrome Devs  Chromium
+ png.dict                   original     2015, Chrome Devs  Chromium
+ README.txt (this file)     original     2017, Glenn R-P    libpng
+
+ * Dockerfile is a copy of the file used by oss-fuzz. build.sh,
+   png.dict and libpng_read_fuzzer.* are the actual files used by oss-fuzz,
+   which retrieves them from the libpng repository at Github.
+
+To do: exercise the progressive reader and the png encoder.
Index: /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/build.sh
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/build.sh	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/build.sh	(revision 107811)
@@ -0,0 +1,50 @@
+#!/bin/bash -eu
+
+# Copyright 2017-2018 Glenn Randers-Pehrson
+# Copyright 2016 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Revisions by Glenn Randers-Pehrson, 2017:
+# 1. Build only the library, not the tools (changed "make -j$(nproc) all" to
+#     "make -j$(nproc) libpng16.la").
+# 2. Disabled WARNING and WRITE options in pnglibconf.dfa.
+# 3. Build zlib alongside libpng
+################################################################################
+
+# Disable logging via library build configuration control.
+cat scripts/pnglibconf.dfa | \
+  sed -e "s/option STDIO/option STDIO disabled/" \
+      -e "s/option WARNING /option WARNING disabled/" \
+      -e "s/option WRITE enables WRITE_INT_FUNCTIONS/option WRITE disabled/" \
+> scripts/pnglibconf.dfa.temp
+mv scripts/pnglibconf.dfa.temp scripts/pnglibconf.dfa
+
+# build the libpng library.
+autoreconf -f -i
+./configure --with-libpng-prefix=OSS_FUZZ_
+make -j$(nproc) clean
+make -j$(nproc) libpng16.la
+
+# build libpng_read_fuzzer.
+$CXX $CXXFLAGS -std=c++11 -I. \
+     $SRC/libpng/contrib/oss-fuzz/libpng_read_fuzzer.cc \
+     -o $OUT/libpng_read_fuzzer \
+     -lFuzzingEngine .libs/libpng16.a -lz
+
+# add seed corpus.
+find $SRC/libpng -name "*.png" | grep -v crashers | \
+     xargs zip $OUT/libpng_read_fuzzer_seed_corpus.zip
+
+cp $SRC/libpng/contrib/oss-fuzz/*.dict \
+     $SRC/libpng/contrib/oss-fuzz/*.options $OUT/
Index: /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/libpng_read_fuzzer.cc
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/libpng_read_fuzzer.cc	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/libpng_read_fuzzer.cc	(revision 107811)
@@ -0,0 +1,208 @@
+
+// libpng_read_fuzzer.cc
+// Copyright 2017-2018 Glenn Randers-Pehrson
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that may
+// be found in the LICENSE file https://cs.chromium.org/chromium/src/LICENSE
+
+// The modifications in 2017 by Glenn Randers-Pehrson include
+// 1. addition of a PNG_CLEANUP macro,
+// 2. setting the option to ignore ADLER32 checksums,
+// 3. adding "#include <string.h>" which is needed on some platforms
+//    to provide memcpy().
+// 4. adding read_end_info() and creating an end_info structure.
+// 5. adding calls to png_set_*() transforms commonly used by browsers.
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <vector>
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#define PNG_CLEANUP \
+  if(png_handler.png_ptr) \
+  { \
+    if (png_handler.row_ptr) \
+      png_free(png_handler.png_ptr, png_handler.row_ptr); \
+    if (png_handler.end_info_ptr) \
+      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
+        &png_handler.end_info_ptr); \
+    else if (png_handler.info_ptr) \
+      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
+        nullptr); \
+    else \
+      png_destroy_read_struct(&png_handler.png_ptr, nullptr, nullptr); \
+    png_handler.png_ptr = nullptr; \
+    png_handler.row_ptr = nullptr; \
+    png_handler.info_ptr = nullptr; \
+    png_handler.end_info_ptr = nullptr; \
+  }
+
+struct BufState {
+  const uint8_t* data;
+  size_t bytes_left;
+};
+
+struct PngObjectHandler {
+  png_infop info_ptr = nullptr;
+  png_structp png_ptr = nullptr;
+  png_infop end_info_ptr = nullptr;
+  png_voidp row_ptr = nullptr;
+  BufState* buf_state = nullptr;
+
+  ~PngObjectHandler() {
+    if (row_ptr)
+      png_free(png_ptr, row_ptr);
+    if (end_info_ptr)
+      png_destroy_read_struct(&png_ptr, &info_ptr, &end_info_ptr);
+    else if (info_ptr)
+      png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
+    else
+      png_destroy_read_struct(&png_ptr, nullptr, nullptr);
+    delete buf_state;
+  }
+};
+
+void user_read_data(png_structp png_ptr, png_bytep data, size_t length) {
+  BufState* buf_state = static_cast<BufState*>(png_get_io_ptr(png_ptr));
+  if (length > buf_state->bytes_left) {
+    png_error(png_ptr, "read error");
+  }
+  memcpy(data, buf_state->data, length);
+  buf_state->bytes_left -= length;
+  buf_state->data += length;
+}
+
+void* limited_malloc(png_structp, png_alloc_size_t size) {
+  // libpng may allocate large amounts of memory that the fuzzer reports as
+  // an error. In order to silence these errors, make libpng fail when trying
+  // to allocate a large amount. This allocator used to be in the Chromium
+  // version of this fuzzer.
+  // This number is chosen to match the default png_user_chunk_malloc_max.
+  if (size > 8000000)
+    return nullptr;
+
+  return malloc(size);
+}
+
+void default_free(png_structp, png_voidp ptr) {
+  return free(ptr);
+}
+
+static const int kPngHeaderSize = 8;
+
+// Entry point for LibFuzzer.
+// Roughly follows the libpng book example:
+// http://www.libpng.org/pub/png/book/chapter13.html
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size < kPngHeaderSize) {
+    return 0;
+  }
+
+  std::vector<unsigned char> v(data, data + size);
+  if (png_sig_cmp(v.data(), 0, kPngHeaderSize)) {
+    // not a PNG.
+    return 0;
+  }
+
+  PngObjectHandler png_handler;
+  png_handler.png_ptr = nullptr;
+  png_handler.row_ptr = nullptr;
+  png_handler.info_ptr = nullptr;
+  png_handler.end_info_ptr = nullptr;
+
+  png_handler.png_ptr = png_create_read_struct
+    (PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
+  if (!png_handler.png_ptr) {
+    return 0;
+  }
+
+  png_handler.info_ptr = png_create_info_struct(png_handler.png_ptr);
+  if (!png_handler.info_ptr) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  png_handler.end_info_ptr = png_create_info_struct(png_handler.png_ptr);
+  if (!png_handler.end_info_ptr) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // Use a custom allocator that fails for large allocations to avoid OOM.
+  png_set_mem_fn(png_handler.png_ptr, nullptr, limited_malloc, default_free);
+
+  png_set_crc_action(png_handler.png_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
+#ifdef PNG_IGNORE_ADLER32
+  png_set_option(png_handler.png_ptr, PNG_IGNORE_ADLER32, PNG_OPTION_ON);
+#endif
+
+  // Setting up reading from buffer.
+  png_handler.buf_state = new BufState();
+  png_handler.buf_state->data = data + kPngHeaderSize;
+  png_handler.buf_state->bytes_left = size - kPngHeaderSize;
+  png_set_read_fn(png_handler.png_ptr, png_handler.buf_state, user_read_data);
+  png_set_sig_bytes(png_handler.png_ptr, kPngHeaderSize);
+
+  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // Reading.
+  png_read_info(png_handler.png_ptr, png_handler.info_ptr);
+
+  // reset error handler to put png_deleter into scope.
+  if (setjmp(png_jmpbuf(png_handler.png_ptr))) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  png_uint_32 width, height;
+  int bit_depth, color_type, interlace_type, compression_type;
+  int filter_type;
+
+  if (!png_get_IHDR(png_handler.png_ptr, png_handler.info_ptr, &width,
+                    &height, &bit_depth, &color_type, &interlace_type,
+                    &compression_type, &filter_type)) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // This is going to be too slow.
+  if (width && height > 100000000 / width) {
+    PNG_CLEANUP
+    return 0;
+  }
+
+  // Set several transforms that browsers typically use:
+  png_set_gray_to_rgb(png_handler.png_ptr);
+  png_set_expand(png_handler.png_ptr);
+  png_set_packing(png_handler.png_ptr);
+  png_set_scale_16(png_handler.png_ptr);
+  png_set_tRNS_to_alpha(png_handler.png_ptr);
+
+  int passes = png_set_interlace_handling(png_handler.png_ptr);
+
+  png_read_update_info(png_handler.png_ptr, png_handler.info_ptr);
+
+  png_handler.row_ptr = png_malloc(
+      png_handler.png_ptr, png_get_rowbytes(png_handler.png_ptr,
+                                            png_handler.info_ptr));
+
+  for (int pass = 0; pass < passes; ++pass) {
+    for (png_uint_32 y = 0; y < height; ++y) {
+      png_read_row(png_handler.png_ptr,
+                   static_cast<png_bytep>(png_handler.row_ptr), nullptr);
+    }
+  }
+
+  png_read_end(png_handler.png_ptr, png_handler.end_info_ptr);
+
+  PNG_CLEANUP
+  return 0;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/libpng_read_fuzzer.options
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/libpng_read_fuzzer.options	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/libpng_read_fuzzer.options	(revision 107811)
@@ -0,0 +1,2 @@
+[libfuzzer]
+dict = png.dict
Index: /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/png.dict
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/png.dict	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/oss-fuzz/png.dict	(revision 107811)
@@ -0,0 +1,39 @@
+#
+# AFL dictionary for PNG images
+# -----------------------------
+#
+# Just the basic, standard-originating sections; does not include vendor
+# extensions.
+#
+# Created by Michal Zalewski <lcamtuf@google.com>
+#
+
+header_png="\x89PNG\x0d\x0a\x1a\x0a"
+
+section_IDAT="IDAT"
+section_IEND="IEND"
+section_IHDR="IHDR"
+section_PLTE="PLTE"
+section_bKGD="bKGD"
+section_cHRM="cHRM"
+section_eXIf="eXIf"
+section_fRAc="fRAc"
+section_gAMA="gAMA"
+section_gIFg="gIFg"
+section_gIFt="gIFt"
+section_gIFx="gIFx"
+section_hIST="hIST"
+section_iCCP="iCCP"
+section_iTXt="iTXt"
+section_oFFs="oFFs"
+section_pCAL="pCAL"
+section_pHYs="pHYs"
+section_sBIT="sBIT"
+section_sCAL="sCAL"
+section_sPLT="sPLT"
+section_sRGB="sRGB"
+section_sTER="sTER"
+section_tEXt="tEXt"
+section_tIME="tIME"
+section_tRNS="tRNS"
+section_zTXt="zTXt"
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/README	(revision 107811)
@@ -0,0 +1,5 @@
+
+This demonstrates the use of PNG_USER_CONFIG, pngusr.h and pngusr.dfa
+to build minimal decoder, encoder, and progressive reader applications.
+
+See the individual README and pngusr.dfa files for more explanation.
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/README	(revision 107811)
@@ -0,0 +1,10 @@
+This demonstrates the use of PNG_USER_CONFIG, pngusr.h and pngusr.dfa
+
+The makefile builds a minimal read-only decoder with embedded libpng
+and zlib.
+
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
+
+If you prefer to use the shared libraries, go to contrib/pngminus
+and build the png2pnm application there.
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/makefile
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/makefile	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/makefile	(revision 107811)
@@ -0,0 +1,151 @@
+# Makefile for PngMinus (pngm2pnm)
+# Linux / Unix
+
+#CC=cc
+CC=gcc
+LD=$(CC)
+
+# If awk fails try
+# make AWK=nawk
+
+# If cpp fails try
+# make CPP=/lib/cpp
+
+RM=rm -f
+COPY=cp
+
+CPPFLAGS=-I. -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall
+
+C=.c
+O=.o
+L=.a
+E=
+
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/pngminus
+
+# Zlib (minimal inflate requirements - crc32 is used by libpng)
+# zutil can be eliminated if you provide your own zcalloc and zcfree
+ZSRCS  = adler32$(C) crc32$(C) \
+	 inffast$(C) inflate$(C) inftrees$(C) \
+	 zutil$(C)
+
+# Standard headers
+ZH     = zlib.h crc32.h inffast.h inffixed.h \
+	 inflate.h inftrees.h zutil.h
+
+# Machine generated headers
+ZCONF  = zconf.h
+
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+
+ZOBJS  = adler32$(O) crc32$(O) \
+	 inffast$(O) inflate$(O) inftrees$(O) \
+	 zutil$(O)
+
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+	pngread$(C) pngrio$(C) pngrtran$(C) pngrutil$(C) \
+	pngset$(C) pngtrans$(C)
+
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+
+# Machine generated headers
+PNGCONF=pnglibconf.h
+
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+	pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) \
+	pngset$(O) pngtrans$(O)
+
+PROGSRCS= pngm2pnm$(C)
+PROGHDRS=
+PROGDOCS=
+PROGOBJS= pngm2pnm$(O)
+
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+
+# implicit make rules -------------------------------------------------------
+
+# note: dependencies do not work on implicit rule lines
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+# dependencies
+
+all: pngm2pnm$(E)
+
+pngm2pnm$(E): $(OBJS)
+	$(LD) -o pngm2pnm$(E) $(OBJS)
+
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
+	$(PNGSRC)/scripts/pnglibconf.dfa \
+	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+	$(RM) pnglibconf.h pnglibconf.dfn
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
+	    DFA_XTRA="pngusr.dfa" $@
+
+clean:
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) clean
+	$(RM) pngm2pnm$(O)
+	$(RM) pngm2pnm$(E)
+	$(RM) $(OBJS)
+
+# distclean also removes the copied source and headers
+distclean: clean
+	$(RM) -r scripts # historical reasons
+	$(RM) $(PNGSRCS) $(PNGH)
+	$(RM) $(ZSRCS) $(ZH) $(ZCONF)
+	$(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+	$(RM) $@
+	$(COPY) $(PNGSRC)/$@ $@
+
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+	$(RM) $@
+	$(COPY) $(ZLIBSRC)/$@ $@
+
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+	$(RM) $@
+	@for f in zconf.h.in zconf.in.h zconf.h; do\
+	    test -r $(ZLIBSRC)/$$f &&\
+	    echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+	    $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+	done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+
+pngm2pnm.c: $(PROGSRC)/png2pnm.c
+	$(RM) $@
+	$(COPY) $(PROGSRC)/png2pnm.c $@
+
+# End of makefile for pngm2pnm
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/pngusr.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/pngusr.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/pngusr.dfa	(revision 107811)
@@ -0,0 +1,40 @@
+# pngminim/decoder/pngusr.dfa
+#
+# Copyright (c) 2010-2013 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# First all the build options off:
+
+everything = off
+
+# All that is required is some read code. This example switches
+# on the sequential read code (see ../preader for a progressive
+# read example).
+
+option SEQUENTIAL_READ on
+
+# You must choose fixed or floating point arithmetic:
+# option FLOATING_POINT on
+
+option FIXED_POINT on
+
+# You must chose the internal fixed point implementation or to
+# use the system floating point.  The latter is considerably
+# smaller (by about 1kbyte on an x86 system):
+# option FLOATING_ARITHMETIC on
+
+option FLOATING_ARITHMETIC off
+
+# Your program will probably need other options.  The example
+# program here, pngm2pnm, requires the following.  Take a look
+# at pnglibconf.h to find out the full set of what has to be
+# enabled to make the following work.
+
+option SETJMP on
+option STDIO on
+option READ_EXPAND on
+option READ_STRIP_16_TO_8 on
+option USER_LIMITS on
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/pngusr.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/pngusr.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/decoder/pngusr.h	(revision 107811)
@@ -0,0 +1,23 @@
+/* minrdpngconf.h: headers to make a minimal png-read-only library
+ *
+ * Copyright (c) 2007, 2010-2013 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
+ */
+
+#ifndef MINRDPNGCONF_H
+#define MINRDPNGCONF_H
+
+/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
+
+/* List options to turn off features of the build that do not
+ * affect the API (so are not recorded in pnglibconf.h)
+ */
+
+#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
+
+#endif /* MINRDPNGCONF_H */
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/README	(revision 107811)
@@ -0,0 +1,10 @@
+This demonstrates the use of PNG_USER_CONFIG and pngusr.h
+
+The makefile builds a minimal write-only encoder with embedded libpng
+and zlib.
+
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
+
+If you prefer to use the shared libraries, go to contrib/pngminus
+and build the pnm2png application there.
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/makefile
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/makefile	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/makefile	(revision 107811)
@@ -0,0 +1,150 @@
+# Makefile for PngMinus (pnm2pngm)
+# Linux / Unix
+
+#CC=cc
+CC=gcc
+LD=$(CC)
+
+# If awk fails try
+# make AWK=nawk
+
+# If cpp fails try
+# make CPP=/lib/cpp
+
+RM=rm -f
+COPY=cp
+
+CPPFLAGS=-I. -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall
+
+C=.c
+O=.o
+L=.a
+E=
+
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/pngminus
+
+# Zlib
+ZSRCS  = adler32$(C) compress$(C) crc32$(C) deflate$(C) \
+	 trees$(C) zutil$(C)
+
+# Standard headers
+#ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
+ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
+
+# Machine generated headers
+ZCONF  = zconf.h
+
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+
+# compress is not required; it is needed to link the zlib
+# code because deflate defines an unused API function deflateBound
+# which itself calls compressBound from compress.
+ZOBJS  = adler32$(O) compress$(O) crc32$(O) deflate$(O) \
+	 trees$(O) zutil$(O)
+
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+	pngset$(C) pngtrans$(C) pngwio$(C) pngwrite$(C) \
+	pngwtran$(C) pngwutil$(C)
+
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+
+# Machine generated headers
+PNGCONF=pnglibconf.h
+
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+	pngset$(O) pngtrans$(O) pngwio$(O) pngwrite$(O) \
+	pngwtran$(O) pngwutil$(O)
+
+PROGSRCS= pnm2pngm$(C)
+PROGHDRS=
+PROGDOCS=
+PROGOBJS= pnm2pngm$(O)
+
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+# dependencies
+
+all: pnm2pngm$(E)
+
+pnm2pngm$(E): $(OBJS)
+	$(LD) -o pnm2pngm$(E) $(OBJS)
+
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
+	$(PNGSRC)/scripts/pnglibconf.dfa \
+	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+	$(RM) pnglibconf.h pnglibconf.dfn
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
+	    DFA_XTRA="pngusr.dfa" $@
+
+clean:
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) clean
+	$(RM) pnm2pngm$(O)
+	$(RM) pnm2pngm$(E)
+	$(RM) $(OBJS)
+
+# distclean also removes the copied source and headers
+distclean: clean
+	$(RM) -r scripts # historical reasons
+	$(RM) $(PNGSRCS) $(PNGH)
+	$(RM) $(ZSRCS) $(ZH) $(ZCONF)
+	$(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+	$(RM) $@
+	$(COPY) $(PNGSRC)/$@ $@
+
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+	$(RM) $@
+	$(COPY) $(ZLIBSRC)/$@ $@
+
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+	$(RM) $@
+	@for f in zconf.h.in zconf.in.h zconf.h; do\
+	    test -r $(ZLIBSRC)/$$f &&\
+	    echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+	    $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+	done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+
+pnm2pngm.c: $(PROGSRC)/pnm2png.c
+	$(RM) $@
+	$(COPY) $(PROGSRC)/pnm2png.c $@
+
+# End of makefile for pnm2pngm
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/pngusr.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/pngusr.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/pngusr.dfa	(revision 107811)
@@ -0,0 +1,39 @@
+# pngminim/encoder/pngusr.dfa
+#
+# Copyright (c) 2010-2013 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# First all the build options off:
+
+everything = off
+
+# Switch on the write code - this makes a minimalist encoder
+
+option WRITE on
+
+# These 2 options are required if you need to read PBM (P1 or P4) files.
+option WRITE_INVERT on
+option WRITE_PACK on
+
+# You must choose fixed or floating point arithmetic:
+# option FLOATING_POINT on
+
+option FIXED_POINT on
+
+# You must chose the internal fixed point implementation or to
+# use the system floating point.  The latter is considerably
+# smaller (by about 1kbyte on an x86 system):
+# option FLOATING_ARITHMETIC on
+
+option FLOATING_ARITHMETIC off
+
+# Your program will probably need other options.  The example
+# program here, pnm2pngm, requires the following.  Take a look
+# at pnglibconf.h to find out the full set of what has to be
+# enabled to make the following work.
+
+option SETJMP on
+option STDIO on
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/pngusr.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/pngusr.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/encoder/pngusr.h	(revision 107811)
@@ -0,0 +1,23 @@
+/* minwrpngconf.h: headers to make a minimal png-write-only library
+ *
+ * Copyright (c) 2007, 2010-2013 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
+ */
+
+#ifndef MINWRPNGCONF_H
+#define MINWRPNGCONF_H
+
+/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
+
+/* List options to turn off features of the build that do not
+ * affect the API (so are not recorded in pnglibconf.h)
+ */
+
+#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
+
+#endif /* MINWRPNGCONF_H */
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/README	(revision 107811)
@@ -0,0 +1,15 @@
+This demonstrates the use of PNG_USER_CONFIG and pngusr.h
+
+The makefile builds a minimal read-only progressive decoder with
+embedded libpng, zlib and your system's X library.
+
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
+
+Edit makefile if required, to find your X library and include files,
+then
+
+    make ZLIBSRC=directory
+
+If you prefer to use the shared libraries, go to contrib/gregbook
+and build the rpng2-x application there.
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/makefile
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/makefile	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/makefile	(revision 107811)
@@ -0,0 +1,166 @@
+# Makefile for PngMinus (rpng2)
+# Linux / Unix
+
+#CC=cc
+CC=gcc
+LD=$(CC)
+
+# If awk fails try
+# make AWK=nawk
+
+# If cpp fails try
+# make CPP=/lib/cpp
+
+RM=rm -f
+COPY=cp
+
+#XINC = -I/usr/include			# old-style, stock X distributions
+#XLIB = -L/usr/lib/X11 -lX11		#  (including SGI IRIX)
+
+#XINC = -I/usr/openwin/include		# Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+
+XINC = -I/usr/X11R6/include		# new X distributions (X.org, etc.)
+XLIB = -L/usr/X11R6/lib -lX11
+#XLIB = -L/usr/X11R6/lib64 -lX11	# e.g., Red Hat on AMD64
+
+#XINC = -I/usr/local/include   		# FreeBSD
+#XLIB = -L/usr/local/lib -lX11
+
+#LIBS = $(XLIB)
+LIBS = $(XLIB) -lm                      #platforms that need libm
+
+CPPFLAGS=-I. $(XINC) -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall
+
+C=.c
+O=.o
+L=.a
+E=
+
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/gregbook
+
+# Zlib (minimal inflate requirements - crc32 is used by libpng)
+# zutil can be eliminated if you provide your own zcalloc and zcfree
+ZSRCS  = adler32$(C) crc32$(C) \
+	 inffast$(C) inflate$(C) inftrees$(C) \
+	 zutil$(C)
+
+# Standard headers
+ZH     = zlib.h crc32.h inffast.h inffixed.h \
+	 inflate.h inftrees.h zutil.h
+
+# Machine generated headers
+ZCONF  = zconf.h
+
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+
+ZOBJS  = adler32$(O) crc32$(O) \
+	 inffast$(O) inflate$(O) inftrees$(O) \
+	 zutil$(O)
+
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+	pngpread$(C) pngread$(C) pngrio$(C) pngrtran$(C) pngrutil$(C) \
+	pngset$(C) pngtrans$(C)
+
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+
+# Machine generated headers
+PNGCONF=pnglibconf.h
+
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+	pngpread$(O) pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) \
+	pngset$(O) pngtrans$(O)
+
+PROGSRCS= rpng2-x$(C) readpng2$(C)
+PROGHDRS= readpng2.h
+PROGDOCS= COPYING LICENSE
+PROGOBJS= rpng2-x$(O) readpng2$(O)
+
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+# dependencies
+
+all: $(PROGDOCS) rpng2-x$(E)
+
+rpng2-x$(E): $(OBJS)
+	$(LD) -o rpng2-x$(E) $(OBJS) $(LIBS)
+
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
+	$(PNGSRC)/scripts/pnglibconf.dfa \
+	$(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+	$(RM) pnglibconf.h pnglibconf.dfn
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
+	    DFA_XTRA="pngusr.dfa" $@
+
+clean:
+	$(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+	    srcdir=$(PNGSRC) clean
+	$(RM) rpng2-x$(O)
+	$(RM) rpng2-x$(E)
+	$(RM) $(OBJS)
+
+# distclean also removes the copied source and headers
+distclean: clean
+	$(RM) -r scripts # historical reasons
+	$(RM) $(PNGSRCS) $(PNGH)
+	$(RM) $(ZSRCS) $(ZH) $(ZCONF)
+	$(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+	$(RM) $@
+	$(COPY) $(PNGSRC)/$@ $@
+
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+	$(RM) $@
+	$(COPY) $(ZLIBSRC)/$@ $@
+
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+	$(RM) $@
+	@for f in zconf.h.in zconf.in.h zconf.h; do\
+	    test -r $(ZLIBSRC)/$$f &&\
+	    echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+	    $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+	done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+
+$(PROGSRCS) $(PROGHDRS) $(PROGDOCS): $(PROGSRC)/$@
+	$(RM) $@
+	$(COPY) $(PROGSRC)/$@ $@
+
+# End of makefile for rpng2-x
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/pngusr.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/pngusr.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/pngusr.dfa	(revision 107811)
@@ -0,0 +1,40 @@
+# pngminim/preader/pngusr.dfa
+#
+# Copyright (c) 2010-2013 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# First all the build options off:
+
+everything = off
+
+# Just switch on the progressive read code
+
+option PROGRESSIVE_READ on
+
+# You may choose fixed or floating point APIs:
+# option FLOATING_POINT on
+
+option FIXED_POINT on
+
+# You must chose the internal fixed point implementation or to
+# use the system floating point.  The latter is considerably
+# smaller (by about 1kbyte on an x86 system):
+
+option FLOATING_ARITHMETIC on
+# option FLOATING_ARITHMETIC off
+
+# Your program will probably need other options.  The example
+# program here, rpng2-x, requires the following.  Take a look
+# at pnglibconf.h to find out the full set of what has to be
+# enabled to make the following work.
+
+option SETJMP on
+option STDIO on
+option READ_bKGD on
+option READ_GAMMA on
+option READ_EXPAND on
+option READ_STRIP_16_TO_8 on
+option READ_GRAY_TO_RGB on
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/pngusr.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/pngusr.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminim/preader/pngusr.h	(revision 107811)
@@ -0,0 +1,23 @@
+/* minrdpngconf.h: headers to make a minimal png-read-only library
+ *
+ * Copyright (c) 2009, 2010-2013 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
+ */
+
+#ifndef MINPRDPNGCONF_H
+#define MINPRDPNGCONF_H
+
+/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
+
+/* List options to turn off features of the build that do not
+ * affect the API (so are not recorded in pnglibconf.h)
+ */
+
+#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
+
+#endif /* MINPRDPNGCONF_H */
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminus/CHANGES.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminus/CHANGES.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminus/CHANGES.txt	(revision 107811)
@@ -0,0 +1,14 @@
+
+pnm2png / png2pnm --- conversion from PBM/PGM/PPM-file to PNG-file
+copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+
+version 1.0 - 1999.10.15 - First version.
+        1.1 - 2015.07.29 - Fix memory leaks (Glenn Randers-Pehrson)
+        1.2 - 2017.04.22 - Add buffer-size check
+        1.3 - 2017.08.24 - Fix potential overflow in buffer-size check
+                           (Glenn Randers-Pehrson)
+        1.4 - 2017.08.28 - Add PNGMINUS_UNUSED (Christian Hesse)
+        1.5 - 2018.08.05 - Fix buffer overflow in tokenizer (Cosmin Truta)
+        1.6 - 2018.08.05 - Improve portability and fix style (Cosmin Truta)
+        1.7 - 2019.01.22 - Change license to MIT (Willem van Schaik)
+        1.8 - 2024.01.09 - Fix, improve, modernize (Cosmin Truta)
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminus/CMakeLists.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminus/CMakeLists.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminus/CMakeLists.txt	(revision 107811)
@@ -0,0 +1,41 @@
+# Copyright (c) 2018-2024 Cosmin Truta
+#
+# This software is released under the MIT license. For conditions of
+# distribution and use, see the LICENSE file part of this package.
+
+cmake_minimum_required(VERSION 3.5)
+
+project(PNGMINUS C)
+
+option(PNGMINUS_USE_SYSTEM_PNG
+       "Use the libpng build found in the system" OFF)
+
+add_executable(png2pnm png2pnm.c)
+add_executable(pnm2png pnm2png.c)
+
+if(PNGMINUS_USE_SYSTEM_PNG)
+    # Use the system libpng.
+    find_package(PNG REQUIRED)
+    target_link_libraries(png2pnm PRIVATE PNG::PNG)
+    target_link_libraries(pnm2png PRIVATE PNG::PNG)
+else()
+    # Build and use the internal libpng.
+    # Configure libpng for static linking, to produce single-file executables.
+    set(PNG_STATIC ON
+        CACHE STRING "Build the internal libpng as a static library" FORCE)
+    set(PNG_SHARED OFF
+        CACHE STRING "Build the internal libpng as a shared library" FORCE)
+    set(PNG_FRAMEWORK OFF
+        CACHE STRING "Build the internal libpng as a framework bundle" FORCE)
+    add_subdirectory(../.. libpng)
+    target_include_directories(png2pnm PRIVATE
+        "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../..>"
+        "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/libpng>"
+    )
+    target_include_directories(pnm2png PRIVATE
+        "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../..>"
+        "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/libpng>"
+    )
+    target_link_libraries(png2pnm PRIVATE png_static)
+    target_link_libraries(pnm2png PRIVATE png_static)
+endif()
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminus/LICENSE.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminus/LICENSE.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminus/LICENSE.txt	(revision 107811)
@@ -0,0 +1,22 @@
+
+pnm2png / png2pnm --- conversion from PBM/PGM/PPM-file to PNG-file
+
+copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+The software is provided "as is", without warranty of any kind, express or
+implied, including but not limited to the warranties of merchantability,
+fitness for a particular purpose and noninfringement. In no event shall the
+authors or copyright holders be liable for any claim, damages or other
+liability, whether in an action of contract, tort or otherwise, arising from,
+out of or in connection with the software or the use or other dealings in the
+software.
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminus/Makefile
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminus/Makefile	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminus/Makefile	(revision 107811)
@@ -0,0 +1,62 @@
+# Makefile for PngMinus (png2pnm and pnm2png)
+# Linux / Unix
+
+#CC = cc
+CC = gcc
+LD = $(CC)
+
+RM = rm -f
+
+PNGINC = -I../..
+PNGLIB_SHARED = -L../.. -lpng
+PNGLIB_STATIC = ../../libpng.a
+
+# Uncomment the following if you have a custom zlib build at ../../../zlib
+#ZINC = -I../../../zlib
+#ZLIB_SHARED = -L../../../zlib -lz
+#ZLIB_STATIC = ../../../zlib/libz.a
+
+# Use the system zlib otherwise
+ZLIB_SHARED = -lz
+ZLIB_STATIC = -lz
+
+CPPFLAGS = $(PNGINC) $(ZINC)
+CFLAGS =
+LDFLAGS =
+LIBS_SHARED = $(PNGLIB_SHARED) $(ZLIB_SHARED)
+LIBS_STATIC = $(PNGLIB_STATIC) $(ZLIB_STATIC)
+
+EXEEXT =
+#EXEEXT = .exe
+
+# dependencies
+
+all: png2pnm$(EXEEXT) pnm2png$(EXEEXT) png2pnm-static$(EXEEXT) pnm2png-static$(EXEEXT)
+
+png2pnm.o: png2pnm.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) png2pnm.c
+
+pnm2png.o: pnm2png.c
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) pnm2png.c
+
+png2pnm$(EXEEXT): png2pnm.o
+	$(LD) $(LDFLAGS) -o png2pnm$(EXEEXT) png2pnm.o $(LIBS_SHARED) -lm
+
+pnm2png$(EXEEXT): pnm2png.o
+	$(LD) $(LDFLAGS) -o pnm2png$(EXEEXT) pnm2png.o $(LIBS_SHARED) -lm
+
+png2pnm-static$(EXEEXT): png2pnm.o
+	$(LD) $(LDFLAGS) -o png2pnm-static$(EXEEXT) png2pnm.o $(LIBS_STATIC) -lm
+
+pnm2png-static$(EXEEXT): pnm2png.o
+	$(LD) $(LDFLAGS) -o pnm2png-static$(EXEEXT) pnm2png.o $(LIBS_STATIC) -lm
+
+clean:
+	$(RM) png2pnm.o
+	$(RM) pnm2png.o
+	$(RM) png2pnm$(EXEEXT)
+	$(RM) pnm2png$(EXEEXT)
+	$(RM) png2pnm-static$(EXEEXT)
+	$(RM) pnm2png-static$(EXEEXT)
+
+# End of makefile for png2pnm / pnm2png
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminus/README.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminus/README.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminus/README.txt	(revision 107811)
@@ -0,0 +1,120 @@
+PngMinus
+--------
+(copyright Willem van Schaik, 1999-2019)
+
+
+
+Some history
+------------
+Soon after the creation of PNG in 1995, the need was felt for a set of
+pnmtopng / pngtopnm utilities. Independently Alexander Lehmann and I
+(Willem van Schaik) started such a project. Luckily we discovered this
+and merged the two, which later became part of NetPBM, available from
+SourceForge.
+
+These two utilities have many, many options and make use of most of the
+features of PNG, like gamma, alpha, sbit, text-chunks, etc. This makes
+the utilities quite complex and by now not anymore very maintainable.
+When we wrote these programs, libpng was still in an early stage.
+Therefore, lots of the functionality that we put in our software can now
+be done using transform-functions in libpng.
+
+Finally, to compile these programs, you need to have installed and
+compiled three libraries: libpng, zlib and netpbm. Especially the latter
+makes the whole setup a bit bulky. But that's unavoidable given the many
+features of pnmtopng.
+
+
+What now (1999)
+---------------
+At this moment libpng is in a very stable state and can do much of the
+work done in pnmtopng. Also, pnmtopng needs to be upgraded to the new
+interface of libpng. Hence, it is time for a rewrite from the ground up
+of pnmtopng and pngtopnm. This will happen in the near future (stay
+tuned). The new package will get a different name to distinguish it from
+the old one: PngPlus.
+
+To experiment a bit with the new interface of libpng, I started off with
+a small prototype that contains only the basic functionality. It doesn't
+have any of the options to read or write special chunks and it will do
+no gamma correction. But this makes it also a simple program that is
+quite easy to understand and can serve well as a template for other
+software developments. By now there are of course a couple of programs,
+like Greg Roelofs' rpng/wpng, that can be used just as good.
+
+
+Can and can not
+---------------
+As this is the small brother of the future PngPlus, I called this fellow
+PngMinus. Because I started this development in good-old Turbo-C, I
+avoided the use the netpbm library, which requires DOS extenders. Again,
+another reason to call it PngMinus (minus netpbm :-). So, part of the
+program are some elementary routines to read / write pgm- and ppm-files.
+It does not handle B&W pbm-files, but instead you could do pgm with bit-
+depth 1.
+
+The downside of this approach is that you can not use them on images
+that require blocks of memory bigger than 64k (the DOS version). For
+larger images you will get an out-of-memory error.
+
+As said before, PngMinus doesn't correct for gamma. When reading
+png-files you can do this just as well by piping the output of png2pnm
+to pnmgamma, one of the standard PbmPlus tools. This same scenario will
+most probably also be followed in the full-blown future PngPlus, with
+the addition of course of the possibility to create gamma-chunks when
+writing png-files.
+
+On the other hand it supports alpha-channels. When reading a png-image
+you can write the alpha-channel into a pgm-file. And when creating an
+RGB+A png-image, you just combine a ppm-file with a corresponding
+pgm-file containing the alpha-channel. When reading, transparency chunks
+are converted into an alpha-channel and from there on treated the same
+way.
+
+Finally you can opt for writing ascii or binary pgm- and ppm-files. When
+the bit-depth is 16, the format will always be ascii.
+
+
+Using it
+--------
+To distinguish them from pnmtopng and PngPlus, the utilities are named
+png2pnm and pnm2png (2 instead of to). The input- and output-files can
+be given as parameters or through redirection. Therefore the programs
+can be part of a pipe.
+
+To list the options type "png2pnm -h" or "pnm2png -h".
+
+
+Just like Scandinavian furniture
+--------------------------------
+You have to put it together yourself. I developed the software on MS-DOS
+with Turbo-C 3.0 and RedHat Linux 4.2 with gcc. In both cases I used
+libpng-1.0.4 and zlib-1.1.3. By now (2019) it is twenty years later and
+more current versions are OK.
+
+The makefile assumes that the libpng libraries can be found in ../.. and
+libz in ../../../zlib. But you can change this to for example ../libpng
+and ../zlib. The makefile creates two versions of each program, one with
+static library support and the other using shared libraries.
+
+If you create a ../pngsuite directory and then store the basn####.png
+files from PngSuite (http://www.schaik.com/pngsuite/) in there, you can
+test the proper functioning of PngMinus by running pngminus.sh.
+
+
+Warranty
+-------
+Please, remember that this was just a small experiment to learn a few
+things. It will have many unforeseen features <vbg> ... who said bugs? Use
+it when you are in need for something simple or when you want a starting
+point for developing your own stuff.
+
+
+The end
+-------
+Willem van Schaik
+mailto:willem at schaik dot com
+http://www.schaik.com/png/
+
+Oct 1999, Jan 2019
+
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminus/makevms.com
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminus/makevms.com	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminus/makevms.com	(revision 107811)
@@ -0,0 +1,92 @@
+$!------------------------------------------------------------------------------
+$! make Contrib programs of libpng under OpenVMS
+$!
+$!
+$! Look for the compiler used
+$!
+$ zlibsrc = "[---.zlib]"
+$ ccopt="/include=(''zlibsrc',[--])"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$ open/write lopt lib.opt
+$ write lopt "[--]libpng.olb/lib"
+$ write lopt "''zlibsrc'libz.olb/lib"
+$ close lopt
+$ open/write xopt x11.opt
+$ write xopt "sys$library:decw$xlibshr.exe/share"
+$ close xopt
+$ write sys$output "Compiling PNG contrib programs ..."
+$   write sys$output "Building pnm2png..."
+$   CALL MAKE pnm2png.OBJ "cc ''CCOPT' pnm2png" -
+	pnm2png.c
+$   call make pnm2png.exe -
+	"LINK pnm2png,lib.opt/opt" -
+	pnm2png.obj
+$   write sys$output "Building png2pnm..."
+$   CALL MAKE png2pnm.OBJ "cc ''CCOPT' png2pnm" -
+	png2pnm.c
+$   call make png2pnm.exe -
+	"LINK png2pnm,lib.opt/opt" -
+	png2pnm.obj
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminus/png2pnm.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminus/png2pnm.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminus/png2pnm.c	(revision 107811)
@@ -0,0 +1,387 @@
+/*
+ *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
+ *  copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+ *
+ *  This software is released under the MIT license. For conditions of
+ *  distribution and use, see the LICENSE file part of this package.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+
+#ifndef BOOL
+#define BOOL unsigned char
+#endif
+#ifndef TRUE
+#define TRUE ((BOOL) 1)
+#endif
+#ifndef FALSE
+#define FALSE ((BOOL) 0)
+#endif
+
+#include "png.h"
+
+/* function prototypes */
+
+int main (int argc, char *argv[]);
+void usage ();
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
+              BOOL raw, BOOL alpha);
+BOOL do_png2pnm (png_struct *png_ptr, png_info *info_ptr,
+                 FILE *pnm_file, FILE *alpha_file,
+                 BOOL raw, BOOL alpha);
+
+/*
+ *  main
+ */
+
+int main (int argc, char *argv[])
+{
+  FILE *fp_rd = stdin;
+  FILE *fp_wr = stdout;
+  FILE *fp_al = NULL;
+  const char *fname_wr = NULL;
+  const char *fname_al = NULL;
+  BOOL raw = TRUE;
+  BOOL alpha = FALSE;
+  int argi;
+  int ret;
+
+  for (argi = 1; argi < argc; argi++)
+  {
+    if (argv[argi][0] == '-')
+    {
+      switch (argv[argi][1])
+      {
+        case 'n':
+          raw = FALSE;
+          break;
+        case 'r':
+          raw = TRUE;
+          break;
+        case 'a':
+          alpha = TRUE;
+          argi++;
+          if ((fp_al = fopen (argv[argi], "wb")) == NULL)
+          {
+            fname_al = argv[argi];
+            fprintf (stderr, "PNM2PNG\n");
+            fprintf (stderr, "Error:  cannot create alpha-channel file %s\n",
+                     argv[argi]);
+            exit (1);
+          }
+          break;
+        case 'h':
+        case '?':
+          usage ();
+          exit (0);
+          break;
+        default:
+          fprintf (stderr, "PNG2PNM\n");
+          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
+          usage ();
+          exit (1);
+          break;
+      } /* end switch */
+    }
+    else if (fp_rd == stdin)
+    {
+      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
+      {
+        fprintf (stderr, "PNG2PNM\n");
+        fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else if (fp_wr == stdout)
+    {
+      fname_wr = argv[argi];
+      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
+      {
+        fprintf (stderr, "PNG2PNM\n");
+        fprintf (stderr, "Error:  cannot create file %s\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else
+    {
+      fprintf (stderr, "PNG2PNM\n");
+      fprintf (stderr, "Error:  too many parameters\n");
+      usage ();
+      exit (1);
+    }
+  } /* end for */
+
+#if defined(O_BINARY) && (O_BINARY != 0)
+  /* set stdin/stdout if required to binary */
+  if (fp_rd == stdin)
+    setmode (fileno (stdin), O_BINARY);
+  if ((raw) && (fp_wr == stdout))
+    setmode (fileno (stdout), O_BINARY);
+#endif
+
+  /* call the conversion program itself */
+  ret = png2pnm (fp_rd, fp_wr, fp_al, raw, alpha);
+
+  /* close input file */
+  fclose (fp_rd);
+  /* close output file */
+  fclose (fp_wr);
+  /* close alpha file */
+  if (alpha)
+    fclose (fp_al);
+
+  if (!ret)
+  {
+    fprintf (stderr, "PNG2PNM\n");
+    fprintf (stderr, "Error:  unsuccessful conversion of PNG-image\n");
+    if (fname_wr)
+      remove (fname_wr); /* no broken output file shall remain behind */
+    if (fname_al)
+      remove (fname_al); /* ditto */
+    exit (1);
+  }
+
+  return 0;
+}
+
+/*
+ *  usage
+ */
+
+void usage ()
+{
+  fprintf (stderr, "PNG2PNM\n");
+  fprintf (stderr, "   by Willem van Schaik, 1999\n");
+  fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
+  fprintf (stderr, "   or:  ... | png2pnm [options]\n");
+  fprintf (stderr, "Options:\n");
+  fprintf (stderr,
+      "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
+  fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
+  fprintf (stderr,
+      "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
+  fprintf (stderr, "   -h | -?  print this help-information\n");
+}
+
+/*
+ *  png2pnm
+ */
+
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
+              BOOL raw, BOOL alpha)
+{
+  png_struct    *png_ptr;
+  png_info      *info_ptr;
+  BOOL          ret;
+
+  /* initialize the libpng context for reading from png_file */
+
+  png_ptr = png_create_read_struct (png_get_libpng_ver(NULL),
+                                    NULL, NULL, NULL);
+  if (!png_ptr)
+    return FALSE; /* out of memory */
+
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_read_struct (&png_ptr, NULL, NULL);
+    return FALSE; /* out of memory */
+  }
+
+  if (setjmp (png_jmpbuf (png_ptr)))
+  {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    return FALSE; /* generic libpng error */
+  }
+
+  png_init_io (png_ptr, png_file);
+
+  /* do the actual conversion */
+  ret = do_png2pnm (png_ptr, info_ptr, pnm_file, alpha_file, raw, alpha);
+
+  /* clean up the libpng structures and their internally-managed data */
+  png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+
+  return ret;
+}
+
+/*
+ *  do_png2pnm - does the conversion in a fully-initialized libpng context
+ */
+
+BOOL do_png2pnm (png_struct *png_ptr, png_info *info_ptr,
+                 FILE *pnm_file, FILE *alpha_file,
+                 BOOL raw, BOOL alpha)
+{
+  png_byte      **row_pointers;
+  png_byte      *pix_ptr;
+  png_uint_32   width;
+  png_uint_32   height;
+  int           bit_depth;
+  int           channels;
+  int           color_type;
+  int           alpha_present;
+  png_uint_32   row, col, i;
+  long          dep_16;
+
+  /* set up the image transformations that are necessary for the PNM format */
+
+  /* set up (if applicable) the expansion of paletted images to full-color rgb,
+   * and the expansion of transparency maps to full alpha-channel */
+  png_set_expand (png_ptr);
+
+  /* set up (if applicable) the expansion of grayscale images to bit-depth 8 */
+  png_set_expand_gray_1_2_4_to_8 (png_ptr);
+
+#ifdef NJET
+  /* downgrade 16-bit images to 8-bit */
+  if (bit_depth == 16)
+    png_set_strip_16 (png_ptr);
+  /* transform grayscale images into full-color */
+  if (color_type == PNG_COLOR_TYPE_GRAY ||
+      color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    png_set_gray_to_rgb (png_ptr);
+  /* if the PNG image has a gAMA chunk then gamma-correct the output image */
+  {
+    double file_gamma;
+    if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))
+      png_set_gamma (png_ptr, (double) 2.2, file_gamma);
+  }
+#endif
+
+  /* read the image file, with all of the above image transforms applied */
+  png_read_png (png_ptr, info_ptr, 0, NULL);
+
+  /* get the image size, bit-depth and color-type */
+  png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+                NULL, NULL, NULL);
+
+  /* calculate the number of channels and store alpha-presence */
+  if (color_type == PNG_COLOR_TYPE_GRAY)
+    channels = 1;
+  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    channels = 2;
+  else if (color_type == PNG_COLOR_TYPE_RGB)
+    channels = 3;
+  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+    channels = 4;
+  else
+    channels = 0; /* should never happen */
+  alpha_present = (channels - 1) % 2;
+
+  /* check if alpha is expected to be present in file */
+  if (alpha && !alpha_present)
+  {
+    fprintf (stderr, "PNG2PNM\n");
+    fprintf (stderr, "Warning:  no alpha channel in PNG file\n");
+    return FALSE;
+  }
+
+  /* get address of internally-allocated image data */
+  row_pointers = png_get_rows (png_ptr, info_ptr);
+
+  /* write header of PNM file */
+
+  if ((color_type == PNG_COLOR_TYPE_GRAY) ||
+      (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+  {
+    fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2");
+    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
+    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+  else if ((color_type == PNG_COLOR_TYPE_RGB) ||
+           (color_type == PNG_COLOR_TYPE_RGB_ALPHA))
+  {
+    fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3");
+    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
+    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+
+  /* write header of PGM file with alpha channel */
+
+  if ((alpha) &&
+      ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||
+       (color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+  {
+    fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2");
+    fprintf (alpha_file, "%d %d\n", (int) width, (int) height);
+    fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+
+  /* write data to PNM file */
+
+  for (row = 0; row < height; row++)
+  {
+    pix_ptr = row_pointers[row];
+    for (col = 0; col < width; col++)
+    {
+      for (i = 0; i < (png_uint_32) (channels - alpha_present); i++)
+      {
+        if (raw)
+        {
+          fputc ((int) *pix_ptr++, pnm_file);
+          if (bit_depth == 16)
+            fputc ((int) *pix_ptr++, pnm_file);
+        }
+        else
+        {
+          if (bit_depth == 16)
+          {
+            dep_16 = ((long) *pix_ptr++) << 8;
+            dep_16 += ((long) *pix_ptr++);
+            fprintf (pnm_file, "%ld ", dep_16);
+          }
+          else
+          {
+            fprintf (pnm_file, "%ld ", (long) *pix_ptr++);
+          }
+        }
+      }
+      if (alpha_present)
+      {
+        if (!alpha)
+        {
+          /* skip the alpha-channel */
+          pix_ptr++;
+          if (bit_depth == 16)
+            pix_ptr++;
+        }
+        else
+        {
+          /* output the alpha-channel as pgm file */
+          if (raw)
+          {
+            fputc ((int) *pix_ptr++, alpha_file);
+            if (bit_depth == 16)
+              fputc ((int) *pix_ptr++, alpha_file);
+          }
+          else
+          {
+            if (bit_depth == 16)
+            {
+              dep_16 = ((long) *pix_ptr++) << 8;
+              dep_16 += ((long) *pix_ptr++);
+              fprintf (alpha_file, "%ld ", dep_16);
+            }
+            else
+            {
+              fprintf (alpha_file, "%ld ", (long) *pix_ptr++);
+            }
+          }
+        }
+      } /* end if alpha_present */
+
+      if (!raw)
+        if (col % 4 == 3)
+          fprintf (pnm_file, "\n");
+    } /* end for col */
+
+    if (!raw)
+      if (col % 4 != 0)
+        fprintf (pnm_file, "\n");
+  } /* end for row */
+
+  return TRUE;
+} /* end of source */
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngminus/pnm2png.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngminus/pnm2png.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngminus/pnm2png.c	(revision 107811)
@@ -0,0 +1,663 @@
+/*
+ *  pnm2png.c --- conversion from PBM/PGM/PPM-file to PNG-file
+ *  copyright (C) 1999-2019 by Willem van Schaik <willem at schaik dot com>
+ *
+ *  This software is released under the MIT license. For conditions of
+ *  distribution and use, see the LICENSE file part of this package.
+ */
+
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+
+#ifndef BOOL
+#define BOOL unsigned char
+#endif
+#ifndef TRUE
+#define TRUE ((BOOL) 1)
+#endif
+#ifndef FALSE
+#define FALSE ((BOOL) 0)
+#endif
+
+#include "png.h"
+
+/* function prototypes */
+
+int main (int argc, char *argv[]);
+void usage ();
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file,
+              BOOL interlace, BOOL alpha);
+BOOL do_pnm2png (png_struct *png_ptr, png_info *info_ptr,
+                 FILE *pnm_file, FILE *alpha_file,
+                 BOOL interlace, BOOL alpha);
+int fscan_pnm_magic (FILE *pnm_file, char *magic_buf, size_t magic_buf_size);
+int fscan_pnm_token (FILE *pnm_file, char *token_buf, size_t token_buf_size);
+int fscan_pnm_uint_32 (FILE *pnm_file, png_uint_32 *num_ptr);
+png_uint_32 get_pnm_data (FILE *pnm_file, int depth);
+png_uint_32 get_pnm_value (FILE *pnm_file, int depth);
+
+/*
+ *  main
+ */
+
+int main (int argc, char *argv[])
+{
+  FILE *fp_rd = stdin;
+  FILE *fp_al = NULL;
+  FILE *fp_wr = stdout;
+  const char *fname_wr = NULL;
+  BOOL interlace = FALSE;
+  BOOL alpha = FALSE;
+  int argi;
+  int ret;
+
+  for (argi = 1; argi < argc; argi++)
+  {
+    if (argv[argi][0] == '-')
+    {
+      switch (argv[argi][1])
+      {
+        case 'i':
+          interlace = TRUE;
+          break;
+        case 'a':
+          alpha = TRUE;
+          argi++;
+          if ((fp_al = fopen (argv[argi], "rb")) == NULL)
+          {
+            fprintf (stderr, "PNM2PNG\n");
+            fprintf (stderr, "Error:  alpha-channel file %s does not exist\n",
+                     argv[argi]);
+            exit (1);
+          }
+          break;
+        case 'h':
+        case '?':
+          usage ();
+          exit (0);
+          break;
+        default:
+          fprintf (stderr, "PNM2PNG\n");
+          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
+          usage ();
+          exit (1);
+          break;
+      } /* end switch */
+    }
+    else if (fp_rd == stdin)
+    {
+      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
+      {
+        fprintf (stderr, "PNM2PNG\n");
+        fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else if (fp_wr == stdout)
+    {
+      fname_wr = argv[argi];
+      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
+      {
+        fprintf (stderr, "PNM2PNG\n");
+        fprintf (stderr, "Error:  cannot create PNG-file %s\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else
+    {
+      fprintf (stderr, "PNM2PNG\n");
+      fprintf (stderr, "Error:  too many parameters\n");
+      usage ();
+      exit (1);
+    }
+  } /* end for */
+
+#if defined(O_BINARY) && (O_BINARY != 0)
+  /* set stdin/stdout to binary,
+   * we're reading the PNM always! in binary format
+   */
+  if (fp_rd == stdin)
+    setmode (fileno (stdin), O_BINARY);
+  if (fp_wr == stdout)
+    setmode (fileno (stdout), O_BINARY);
+#endif
+
+  /* call the conversion program itself */
+  ret = pnm2png (fp_rd, fp_wr, fp_al, interlace, alpha);
+
+  /* close input file */
+  fclose (fp_rd);
+  /* close output file */
+  fclose (fp_wr);
+  /* close alpha file */
+  if (alpha)
+    fclose (fp_al);
+
+  if (!ret)
+  {
+    fprintf (stderr, "PNM2PNG\n");
+    fprintf (stderr, "Error:  unsuccessful converting to PNG-image\n");
+    if (fname_wr)
+      remove (fname_wr); /* no broken output file shall remain behind */
+    exit (1);
+  }
+
+  return 0;
+}
+
+/*
+ *  usage
+ */
+
+void usage ()
+{
+  fprintf (stderr, "PNM2PNG\n");
+  fprintf (stderr, "   by Willem van Schaik, 1999\n");
+  fprintf (stderr, "Usage:  pnm2png [options] <file>.<pnm> [<file>.png]\n");
+  fprintf (stderr, "   or:  ... | pnm2png [options]\n");
+  fprintf (stderr, "Options:\n");
+  fprintf (stderr, "   -i[nterlace]   write png-file with interlacing on\n");
+  fprintf (stderr,
+      "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
+  fprintf (stderr, "   -h | -?  print this help-information\n");
+}
+
+/*
+ *  pnm2png
+ */
+
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file,
+              BOOL interlace, BOOL alpha)
+{
+  png_struct    *png_ptr;
+  png_info      *info_ptr;
+  BOOL          ret;
+
+  /* initialize the libpng context for writing to png_file */
+
+  png_ptr = png_create_write_struct (png_get_libpng_ver(NULL),
+                                     NULL, NULL, NULL);
+  if (!png_ptr)
+    return FALSE; /* out of memory */
+
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_write_struct (&png_ptr, NULL);
+    return FALSE; /* out of memory */
+  }
+
+  if (setjmp (png_jmpbuf (png_ptr)))
+  {
+    png_destroy_write_struct (&png_ptr, &info_ptr);
+    return FALSE; /* generic libpng error */
+  }
+
+  png_init_io (png_ptr, png_file);
+
+  /* do the actual conversion */
+  ret = do_pnm2png (png_ptr, info_ptr, pnm_file, alpha_file, interlace, alpha);
+
+  /* clean up the libpng structures and their internally-managed data */
+  png_destroy_write_struct (&png_ptr, &info_ptr);
+
+  return ret;
+}
+
+/*
+ *  do_pnm2png - does the conversion in a fully-initialized libpng context
+ */
+
+BOOL do_pnm2png (png_struct *png_ptr, png_info *info_ptr,
+                 FILE *pnm_file, FILE *alpha_file,
+                 BOOL interlace, BOOL alpha)
+{
+  png_byte      **row_pointers;
+  png_byte      *pix_ptr;
+  int           bit_depth;
+  int           color_type;
+  int           channels;
+  char          magic_token[4];
+  BOOL          raw;
+  png_uint_32   width, height, maxval;
+  png_uint_32   row_bytes;
+  png_uint_32   row, col;
+  png_uint_32   val16, i;
+  png_uint_32   alpha_width = 0, alpha_height = 0;
+  int           alpha_depth = 0, alpha_present = 0;
+  BOOL          alpha_raw = FALSE;
+  BOOL          packed_bitmap = FALSE;
+
+  /* read header of PNM file */
+
+  if (fscan_pnm_magic (pnm_file, magic_token, sizeof (magic_token)) != 1)
+    return FALSE; /* not a PNM file */
+
+  if ((magic_token[1] == '1') || (magic_token[1] == '4'))
+  {
+    if ((fscan_pnm_uint_32 (pnm_file, &width) != 1) ||
+        (fscan_pnm_uint_32 (pnm_file, &height) != 1))
+      return FALSE; /* bad PBM file header */
+  } else if ((magic_token[1] == '2') || (magic_token[1] == '5') ||
+             (magic_token[1] == '3') || (magic_token[1] == '6'))
+  {
+    if ((fscan_pnm_uint_32 (pnm_file, &width) != 1) ||
+        (fscan_pnm_uint_32 (pnm_file, &height) != 1) ||
+        (fscan_pnm_uint_32 (pnm_file, &maxval) != 1))
+      return FALSE; /* bad PGM/PPM file header */
+  }
+
+  if ((magic_token[1] == '1') || (magic_token[1] == '4'))
+  {
+    raw = (magic_token[1] == '4');
+    bit_depth = 1;
+    color_type = PNG_COLOR_TYPE_GRAY;
+    packed_bitmap = TRUE;
+  }
+  else if ((magic_token[1] == '2') || (magic_token[1] == '5'))
+  {
+    raw = (magic_token[1] == '5');
+    color_type = PNG_COLOR_TYPE_GRAY;
+    if (maxval == 0)
+      return FALSE;
+    else if (maxval == 1)
+      bit_depth = 1;
+    else if (maxval <= 3)
+      bit_depth = 2;
+    else if (maxval <= 15)
+      bit_depth = 4;
+    else if (maxval <= 255)
+      bit_depth = 8;
+    else if (maxval <= 65535U)
+      bit_depth = 16;
+    else /* maxval > 65535U */
+      return FALSE;
+  }
+  else if ((magic_token[1] == '3') || (magic_token[1] == '6'))
+  {
+    raw = (magic_token[1] == '6');
+    color_type = PNG_COLOR_TYPE_RGB;
+    if (maxval == 0)
+      return FALSE;
+    else if (maxval == 1)
+      bit_depth = 1;
+    else if (maxval <= 3)
+      bit_depth = 2;
+    else if (maxval <= 15)
+      bit_depth = 4;
+    else if (maxval <= 255)
+      bit_depth = 8;
+    else if (maxval <= 65535U)
+      bit_depth = 16;
+    else /* maxval > 65535U */
+      return FALSE;
+  }
+  else if (magic_token[1] == '7')
+  {
+    fprintf (stderr, "PNM2PNG can't read PAM (P7) files\n");
+    return FALSE;
+  }
+  else
+  {
+    return FALSE;
+  }
+
+  /* read header of PGM file with alpha channel */
+
+  if (alpha)
+  {
+    if ((fscan_pnm_magic (alpha_file, magic_token, sizeof (magic_token)) != 1)
+        || ((magic_token[1] != '2') && (magic_token[1] != '5')))
+      return FALSE; /* not a PGM file */
+
+    if ((fscan_pnm_uint_32 (alpha_file, &alpha_width) != 1) ||
+        (fscan_pnm_uint_32 (alpha_file, &alpha_height) != 1) ||
+        (fscan_pnm_uint_32 (alpha_file, &maxval) != 1))
+      return FALSE; /* bad PGM file header */
+
+    if ((alpha_width != width) || (alpha_height != height))
+      return FALSE; /* mismatched PGM dimensions */
+
+    alpha_raw = (magic_token[1] == '5');
+    color_type |= PNG_COLOR_MASK_ALPHA;
+    if (maxval == 0)
+      return FALSE;
+    else if (maxval == 1)
+      alpha_depth = 1;
+    else if (maxval <= 3)
+      alpha_depth = 2;
+    else if (maxval <= 15)
+      alpha_depth = 4;
+    else if (maxval <= 255)
+      alpha_depth = 8;
+    else if (maxval <= 65535U)
+      alpha_depth = 16;
+    else /* maxval > 65535U */
+      return FALSE;
+    if (alpha_depth != bit_depth)
+      return FALSE;
+  } /* end if alpha */
+
+  /* calculate the number of channels and store alpha-presence */
+  if (color_type == PNG_COLOR_TYPE_GRAY)
+    channels = 1;
+  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    channels = 2;
+  else if (color_type == PNG_COLOR_TYPE_RGB)
+    channels = 3;
+  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+    channels = 4;
+  else
+    return FALSE; /* NOTREACHED */
+
+  alpha_present = (channels - 1) % 2;
+
+  if (packed_bitmap)
+  {
+    /* row data is as many bytes as can fit width x channels x bit_depth */
+    row_bytes = (width * channels * bit_depth + 7) / 8;
+  }
+  else
+  {
+    /* row_bytes is the width x number of channels x (bit-depth / 8) */
+    row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);
+  }
+
+  if ((row_bytes == 0) ||
+      ((size_t) height > (size_t) (-1) / (size_t) row_bytes))
+  {
+    /* too big */
+    return FALSE;
+  }
+
+  /* allocate the rows using the same memory layout as libpng, and transfer
+   * their ownership to libpng, with the responsibility to clean everything up;
+   * please note the use of png_calloc instead of png_malloc */
+  row_pointers = (png_byte **)
+                 png_calloc (png_ptr, height * sizeof (png_byte *));
+  png_set_rows (png_ptr, info_ptr, row_pointers);
+  png_data_freer (png_ptr, info_ptr, PNG_DESTROY_WILL_FREE_DATA, PNG_FREE_ALL);
+  for (row = 0; row < height; row++)
+  {
+    /* the individual rows should only be allocated after all the previous
+     * steps completed successfully, because libpng must handle correctly
+     * any image allocation left incomplete after an out-of-memory error */
+    row_pointers[row] = (png_byte *) png_malloc (png_ptr, row_bytes);
+  }
+
+  /* read the data from PNM file */
+
+  for (row = 0; row < height; row++)
+  {
+    pix_ptr = row_pointers[row];
+    if (packed_bitmap)
+    {
+      for (i = 0; i < row_bytes; i++)
+      {
+        /* png supports this format natively so no conversion is needed */
+        *pix_ptr++ = get_pnm_data (pnm_file, 8);
+      }
+    }
+    else
+    {
+      for (col = 0; col < width; col++)
+      {
+        for (i = 0; i < (png_uint_32) (channels - alpha_present); i++)
+        {
+          if (raw)
+          {
+            *pix_ptr++ = get_pnm_data (pnm_file, bit_depth);
+            if (bit_depth == 16)
+              *pix_ptr++ = get_pnm_data (pnm_file, bit_depth);
+          }
+          else
+          {
+            if (bit_depth <= 8)
+            {
+              *pix_ptr++ = get_pnm_value (pnm_file, bit_depth);
+            }
+            else
+            {
+              val16 = get_pnm_value (pnm_file, bit_depth);
+              *pix_ptr = (png_byte) ((val16 >> 8) & 0xFF);
+              pix_ptr++;
+              *pix_ptr = (png_byte) (val16 & 0xFF);
+              pix_ptr++;
+            }
+          }
+        }
+
+        if (alpha) /* read alpha-channel from pgm file */
+        {
+          if (alpha_raw)
+          {
+            *pix_ptr++ = get_pnm_data (alpha_file, alpha_depth);
+            if (alpha_depth == 16)
+              *pix_ptr++ = get_pnm_data (alpha_file, alpha_depth);
+          }
+          else
+          {
+            if (alpha_depth <= 8)
+            {
+              *pix_ptr++ = get_pnm_value (alpha_file, bit_depth);
+            }
+            else
+            {
+              val16 = get_pnm_value (alpha_file, bit_depth);
+              *pix_ptr++ = (png_byte) ((val16 >> 8) & 0xFF);
+              *pix_ptr++ = (png_byte) (val16 & 0xFF);
+            }
+          }
+        } /* end if alpha */
+      } /* end if packed_bitmap */
+    } /* end for col */
+  } /* end for row */
+
+  /* we're going to write more or less the same PNG as the input file */
+  png_set_IHDR (png_ptr, info_ptr, width, height, bit_depth, color_type,
+                (!interlace) ? PNG_INTERLACE_NONE : PNG_INTERLACE_ADAM7,
+                PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+  if (packed_bitmap == TRUE)
+  {
+    png_set_packing (png_ptr);
+    png_set_invert_mono (png_ptr);
+  }
+
+  /* write the file header information */
+  png_write_info (png_ptr, info_ptr);
+
+  /* write out the entire image data in one call */
+  png_write_image (png_ptr, row_pointers);
+
+  /* write the additional chunks to the PNG file (not really needed) */
+  png_write_end (png_ptr, info_ptr);
+
+  return TRUE;
+} /* end of pnm2png */
+
+/*
+ * fscan_pnm_magic - like fscan_pnm_token below, but expects the magic string
+ *                   to start immediately, without any comment or whitespace,
+ *                   and to match the regex /^P[1-9]$/
+ */
+
+int fscan_pnm_magic (FILE *pnm_file, char *magic_buf, size_t magic_buf_size)
+{
+  int ret;
+
+  ret = fgetc (pnm_file);
+  if (ret == EOF) return 0;
+  ungetc (ret, pnm_file);
+  if (ret != 'P') return 0;
+
+  /* the string buffer must be at least four bytes long, i.e., the capacity
+   * required for strings of at least three characters long, i.e., the minimum
+   * required for ensuring that our magic string is exactly two characters long
+   */
+  if (magic_buf_size < 4) return -1;
+
+  ret = fscan_pnm_token (pnm_file, magic_buf, magic_buf_size);
+  if (ret < 1) return ret;
+
+  if ((magic_buf[1] < '1') || (magic_buf[1] > '9')) return 0;
+  if (magic_buf[2] != '\0') return 0;
+
+  return 1;
+}
+
+/*
+ * fscan_pnm_token - extracts the first string token after whitespace,
+ *                   and (like fscanf) returns the number of successful
+ *                   extractions, which can be either 0 or 1
+ */
+
+int fscan_pnm_token (FILE *pnm_file, char *token_buf, size_t token_buf_size)
+{
+  size_t i = 0;
+  int ret;
+
+  /* remove white-space and comment lines */
+  do
+  {
+    ret = fgetc (pnm_file);
+    if (ret == '#')
+    {
+      /* the rest of this line is a comment */
+      do
+      {
+        ret = fgetc (pnm_file);
+      }
+      while ((ret != '\n') && (ret != '\r') && (ret != EOF));
+    }
+    if (ret == EOF) break;
+    token_buf[i] = (char) ret;
+  }
+  while ((ret == '\n') || (ret == '\r') || (ret == ' '));
+
+  /* read string */
+  do
+  {
+    ret = fgetc (pnm_file);
+    if (ret == EOF) break;
+    if (ret == '0')
+    {
+      /* avoid storing more than one leading '0' in the token buffer,
+       * to ensure that all valid (in-range) numeric inputs can fit in. */
+      if ((i == 0) && (token_buf[i] == '0')) continue;
+    }
+    if (++i == token_buf_size - 1) break;
+    token_buf[i] = (char) ret;
+  }
+  while ((ret != '\n') && (ret != '\r') && (ret != ' '));
+
+  token_buf[i] = '\0';
+  return (i > 0) ? 1 : 0;
+}
+
+/*
+ * fscan_pnm_uint_32 - like fscan_token above, but expects the extracted token
+ *                     to be numeric, and converts it to an unsigned 32-bit int
+ */
+
+int fscan_pnm_uint_32 (FILE *pnm_file, png_uint_32 *num_ptr)
+{
+  char token[16];
+  unsigned long token_value;
+  int ret;
+
+  ret = fscan_pnm_token (pnm_file, token, sizeof (token));
+  if (ret < 1) return ret;
+
+  if ((token[0] < '0') && (token[0] > '9'))
+    return 0; /* the token starts with junk, or a +/- sign, which is invalid */
+
+  ret = sscanf (token, "%lu%*c", &token_value);
+  if (ret != 1)
+    return 0; /* the token ends with junk */
+
+  *num_ptr = (png_uint_32) token_value;
+
+#if ULONG_MAX > 0xFFFFFFFFUL
+  /* saturate the converted number, following the fscanf convention */
+  if (token_value > 0xFFFFFFFFUL)
+    *num_ptr = 0xFFFFFFFFUL;
+#endif
+
+  return 1;
+}
+
+/*
+ *  get_pnm_data - takes first byte and converts into next pixel value,
+ *                 taking as many bits as defined by bit-depth and
+ *                 using the bit-depth to fill up a byte (0x0A -> 0xAA)
+ */
+
+png_uint_32 get_pnm_data (FILE *pnm_file, int depth)
+{
+  static int bits_left = 0;
+  static int old_value = 0;
+  static int mask = 0;
+  png_uint_32 ret_value;
+  int i;
+
+  if (mask == 0)
+    for (i = 0; i < depth; i++)
+      mask = (mask >> 1) | 0x80;
+
+  if (bits_left <= 0)
+  {
+    /* FIXME:
+     * signal the premature end of file, instead of pretending to read zeroes
+     */
+    old_value = fgetc (pnm_file);
+    if (old_value == EOF) return 0;
+    bits_left = 8;
+  }
+
+  ret_value = old_value & mask;
+  for (i = 1; i < (8 / depth); i++)
+    ret_value = ret_value || (ret_value >> depth);
+
+  old_value = (old_value << depth) & 0xFF;
+  bits_left -= depth;
+
+  return ret_value;
+}
+
+/*
+ *  get_pnm_value - takes first (numeric) string and converts into number,
+ *                  using the bit-depth to fill up a byte (0x0A -> 0xAA)
+ */
+
+png_uint_32 get_pnm_value (FILE *pnm_file, int depth)
+{
+  static png_uint_32 mask = 0;
+  png_uint_32 ret_value;
+  int i;
+
+  if (mask == 0)
+    for (i = 0; i < depth; i++)
+      mask = (mask << 1) | 0x01;
+
+  if (fscan_pnm_uint_32 (pnm_file, &ret_value) != 1)
+  {
+    /* FIXME:
+     * signal the invalid numeric tokens or the premature end of file,
+     * instead of pretending to read zeroes
+     */
+    return 0;
+  }
+
+  ret_value &= mask;
+
+  if (depth < 8)
+    for (i = 0; i < (8 / depth); i++)
+      ret_value = (ret_value << depth) || ret_value;
+
+  return ret_value;
+}
+
+/* end of source */
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngsuite/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngsuite/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngsuite/README	(revision 107811)
@@ -0,0 +1,107 @@
+
+pngsuite
+--------
+Copyright (c) Willem van Schaik, 1999, 2011, 2012
+Two images (ftbbn0g01.png and ftbbn0g02.png) are by Glenn Randers-Pehrson, 2012
+
+Permission to use, copy, modify, and distribute these images for any
+purpose and without fee is hereby granted.
+
+The 15 "bas*.png" images are part of the much larger PngSuite test-set of
+images, available for developers of PNG supporting software. The
+complete set, available at http:/www.schaik.com/pngsuite/, contains
+a variety of images to test interlacing, gamma settings, ancillary
+chunks, etc.
+
+The "ft*.png" images are "free/libre" replacements for the transparent
+corresponding t*.png images in the PngSuite.
+
+The "i*.png" images are the same images, but interlaced.
+
+The images in this directory represent the basic PNG color-types:
+grayscale (1-16 bit deep), full color (8 or 16 bit), paletted
+(1-8 bit) and grayscale or color images with alpha channel. You
+can use them to test the proper functioning of PNG software.
+
+    filename       depth type
+    ------------ ------ --------------
+    basn0g01.png   1-bit grayscale
+    basn0g02.png   2-bit grayscale
+    basn0g04.png   4-bit grayscale
+    basn0g08.png   8-bit grayscale
+    basn0g16.png  16-bit grayscale
+    basn2c08.png   8-bit truecolor
+    basn2c16.png  16-bit truecolor
+    basn3p01.png   1-bit paletted
+    basn3p02.png   2-bit paletted
+    basn3p04.png   4-bit paletted
+    basn3p08.png   8-bit paletted
+    basn4a08.png   8-bit gray with alpha
+    basn4a16.png  16-bit gray with alpha
+    basn6a08.png   8-bit RGBA
+    basn6a16.png  16-bit RGBA
+
+    ftbbn0g01.png  1-bit grayscale, black bKGD
+    ftbbn0g02.png  2-bit grayscale, black bKGD
+    ftbbn0g04.png  4-bit grayscale, black bKGD
+    ftbbn2c16.png 16-bit truecolor, black bKGD
+    ftbbn3p08.png  8-bit paletted, black bKGD
+    ftbgn2c16.png 16-bit truecolor, gray bKGD
+    ftbgn3p08.png  8-bit paletted, gray bKGD
+    ftbrn2c08.png  8-bit truecolor, red bKGD
+    ftbwn0g16.png 16-bit gray, white bKGD
+    ftbwn3p08.png  8-bit paletted, white bKGD
+    ftbyn3p08.png  8-bit paletted, yellow bKGD
+    ftp0n0g08.png  8-bit grayscale, opaque
+    ftp0n2c08.png  8-bit truecolor, opaque
+    ftp0n3p08.png  8-bit paletted, opaque
+    ftp1n3p08.png  8-bit paletted, no bKGD
+
+Here is the correct result of typing "pngtest -m bas*.png" in
+this directory:
+
+Testing basn0g01.png: PASS (524 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g02.png: PASS (448 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g04.png: PASS (520 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g08.png: PASS (3 zero samples)
+ Filter 1 was used 9 times
+ Filter 4 was used 23 times
+Testing basn0g16.png: PASS (1 zero samples)
+ Filter 1 was used 1 times
+ Filter 2 was used 31 times
+Testing basn2c08.png: PASS (6 zero samples)
+ Filter 1 was used 5 times
+ Filter 4 was used 27 times
+Testing basn2c16.png: PASS (592 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn3p01.png: PASS (512 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p02.png: PASS (448 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p04.png: PASS (544 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p08.png: PASS (4 zero samples)
+ Filter 0 was used 32 times
+Testing basn4a08.png: PASS (32 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn4a16.png: PASS (64 zero samples)
+ Filter 0 was used 1 times
+ Filter 1 was used 2 times
+ Filter 2 was used 1 times
+ Filter 4 was used 28 times
+Testing basn6a08.png: PASS (160 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn6a16.png: PASS (1072 zero samples)
+ Filter 1 was used 4 times
+ Filter 4 was used 28 times
+libpng passes test
+
+Willem van Schaik
+<willem at schaik.com>
+October 1999
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngsuite/bad_interlace_conversions.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngsuite/bad_interlace_conversions.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngsuite/bad_interlace_conversions.txt	(revision 107811)
@@ -0,0 +1,9 @@
+basn0g01.png
+basn0g02.png
+basn0g04.png
+basn3p01.png
+basn3p02.png
+basn3p04.png
+ftbbn0g01.png
+ftbbn0g02.png
+ftbbn0g04.png
Index: /trunk/src/libs/libpng-1.6.45/contrib/pngsuite/interlaced/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/pngsuite/interlaced/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/pngsuite/interlaced/README	(revision 107811)
@@ -0,0 +1,2 @@
+
+These images fail the "pngimage-quick" and "pngimage-full" tests.
Index: /trunk/src/libs/libpng-1.6.45/contrib/powerpc-vsx/README
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/powerpc-vsx/README	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/powerpc-vsx/README	(revision 107811)
@@ -0,0 +1,81 @@
+OPERATING SYSTEM SPECIFIC POWERPC DETECTION
+--------------------------------------------
+
+Detection of the ability to execute POWERPC on processor requires
+operating system support.  (The information is not available in user mode.)
+
+Currently only this feature is supported only for linux platform.
+
+HOW TO USE THIS
+---------------
+
+This directory contains C code fragments that can be included in powerpc/powerpc_init.c
+by setting the macro PNG_POWERPC_VSX_FILE to the file name in "" or <> at build
+time.  This setting is not recorded in pnglibconf.h and can be changed simply by
+rebuilding arm/arm_init.o with the required macro definition.
+
+For any of this code to be used the POWERPC code must be enabled and run time
+checks must be supported.  I.e.:
+
+#if PNG_POWERPC_VSX_OPT > 0
+#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
+
+This is done in a 'configure' build by passing configure the argument:
+
+   --enable-powerpc-vsx=check
+
+FILE FORMAT
+-----------
+
+Each file documents its testing status as of the last time it was tested (which
+may have been a long time ago):
+
+STATUS: one of:
+   SUPPORTED: This indicates that the file is included in the regularly
+         performed test builds and bugs are fixed when discovered.
+   COMPILED: This indicates that the code did compile at least once.  See the
+         more detailed description for the extent to which the result was
+         successful.
+   TESTED: This means the code was fully compiled into the libpng test programs
+         and these were run at least once.
+
+BUG REPORTS: an email address to which to send reports of problems
+
+The file is a fragment of C code. It should not define any 'extern' symbols;
+everything should be static.  It must define the function:
+
+static int png_have_vsx(png_structp png_ptr);
+
+That function must return 1 if POWERPC_VSX instructions are supported, 0 if not.
+It must not execute png_error unless it detects a bug.  A png_error will prevent
+the reading of the PNG and in the future, writing too.
+
+BUG REPORTS
+-----------
+
+If you mail a bug report for any file that is not SUPPORTED there may only be
+limited response.  Consider fixing it and sending a patch to fix the problem -
+this is more likely to result in action.
+
+CONTRIBUTIONS
+-------------
+
+You may send contributions of new implementations to
+png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
+possible.  Obviously OS dependencies are to be expected.  If you submit code you
+must have the authors permission and it must have a license that is acceptable
+to the current maintainer; in particular that license must permit modification
+and redistribution.
+
+Please try to make the contribution a single file and give the file a clear and
+unambiguous name that identifies the target OS.  If multiple files really are
+required put them all in a sub-directory.
+
+You must also be prepared to handle bug reports from users of the code, either
+by joining the png-mng-implement mailing list or by providing an email for the
+"BUG REPORTS" entry or both.  Please make sure that the header of the file
+contains the STATUS and BUG REPORTS fields as above.
+
+Please list the OS requirements as precisely as possible.  Ideally you should
+also list the environment in which the code has been tested and certainly list
+any environments where you suspect it might not work.
Index: /trunk/src/libs/libpng-1.6.45/contrib/powerpc-vsx/linux.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/powerpc-vsx/linux.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/powerpc-vsx/linux.c	(revision 107811)
@@ -0,0 +1,56 @@
+/* contrib/powerpc-vsx/linux.c
+ *
+ * Copyright (c) 2017 Glenn Randers-Pehrson
+ * Written by Vadim Barkov, 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * STATUS: TESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_vsx implemented for Linux by reading the widely available
+ * pseudo-file /proc/cpuinfo.
+ *
+ * This code is strict ANSI-C and is probably moderately portable; it does
+ * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "png.h"
+
+#ifndef MAXLINE
+#  define MAXLINE 1024
+#endif
+
+static int
+png_have_vsx(png_structp png_ptr)
+{
+   FILE *f;
+
+   const char *string = "altivec supported";
+   char input[MAXLINE];
+   char *token = NULL;
+
+   PNG_UNUSED(png_ptr)
+
+   f = fopen("/proc/cpuinfo", "r");
+   if (f != NULL)
+   {
+      memset(input,0,MAXLINE);
+      while(fgets(input,MAXLINE,f) != NULL)
+      {
+         token = strstr(input,string);
+         if(token != NULL)
+            return 1;
+      }
+   }
+#ifdef PNG_WARNINGS_SUPPORTED
+   else
+      png_warning(png_ptr, "/proc/cpuinfo open failed");
+#endif
+   return 0;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/powerpc-vsx/linux_aux.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/powerpc-vsx/linux_aux.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/powerpc-vsx/linux_aux.c	(revision 107811)
@@ -0,0 +1,33 @@
+/* contrib/powerpc-vsx/linux_aux.c
+ *
+ * Copyright (c) 2017 Glenn Randers-Pehrson
+ * Written by Vadim Barkov, 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * STATUS: TESTED
+ * BUG REPORTS: png-mng-implement@sourceforge.net
+ *
+ * png_have_vsx implemented for Linux by using the auxiliary vector mechanism.
+ *
+ * This code is strict ANSI-C and is probably moderately portable; it does
+ * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
+ */
+
+#include "sys/auxv.h"
+#include "png.h"
+
+static int
+png_have_vsx(png_structp png_ptr)
+{
+   unsigned long auxv = getauxval(AT_HWCAP);
+
+   PNG_UNUSED(png_ptr)
+
+   if(auxv & (PPC_FEATURE_HAS_ALTIVEC|PPC_FEATURE_HAS_VSX))
+      return 1;
+   else
+      return 0;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/testpngs/makepngs.sh
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/testpngs/makepngs.sh	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/testpngs/makepngs.sh	(revision 107811)
@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+
+# Make a set of test PNG files, MAKEPNG is the name of the makepng executable
+# built from contrib/libtests/makepng.c
+
+# Copyright (c) 2015 John Cunningham Bowler
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# The arguments say whether to build all the files or whether just to build the
+# ones that extend the code-coverage of libpng from the existing test files in
+# contrib/pngsuite.
+test -n "$MAKEPNG" || MAKEPNG=./makepng
+opts=
+
+mp(){
+   ${MAKEPNG} $opts $1 "$3" "$4" "$3-$4$2.png"
+}
+
+mpg(){
+   if test "$1" = "none"
+   then
+      mp "" "" "$2" "$3"
+   else
+      mp "--$1" "-$1" "$2" "$3"
+   fi
+}
+
+mptrans(){
+   if test "$1" = "none"
+   then
+      mp "--tRNS" "-tRNS" "$2" "$3"
+   else
+      mp "--tRNS --$1" "-$1-tRNS" "$2" "$3"
+   fi
+}
+
+case "$1" in
+   --small)
+      opts="--small";;&
+
+   --all|--small)
+      for g in none sRGB linear 1.8
+      do
+         for c in gray palette
+         do
+            for b in 1 2 4
+            do
+               mpg "$g" "$c" "$b"
+               mptrans "$g" "$c" "$b"
+            done
+         done
+
+         mpg "$g" palette 8
+         mptrans "$g" palette 8
+
+         for b in 8 16
+         do
+            for c in gray gray-alpha rgb rgb-alpha
+            do
+               mpg "$g" "$c" "$b"
+            done
+            for c in gray rgb
+            do
+               mptrans "$g" "$c" "$b"
+            done
+         done
+      done;;
+
+   --coverage)
+      # Comments below indicate cases known to be required and not duplicated
+      # in other (required) cases; the aim is to get a minimal set that gives
+      # the maximum code coverage.
+      mpg none gray-alpha 8 # required: code coverage, sRGB opaque component
+      mpg none palette 8 # required: basic palette read
+      mpg 1.8 gray 2 # required: tests gamma threshold code
+      mpg 1.8 palette 2 # required: code coverage
+      mpg 1.8 palette 4 # required: code coverage
+      mpg 1.8 palette 8 # error limits only
+      mpg linear palette 8 # error limits only
+      mpg linear rgb-alpha 16 # error limits only
+      mpg sRGB palette 1 # required: code coverage
+      mpg sRGB rgb-alpha 16 # required: code coverage: pngread.c:2422 untested
+      :;;
+
+   *)
+      echo "$0 $1: unknown argument, usage:" >&2
+      echo "  $0 [--all|--coverage|--small]" >&2
+      exit 1
+esac
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/README.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/README.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/README.txt	(revision 107811)
@@ -0,0 +1,27 @@
+This directory (contrib/tools) contains tools used by the authors of libpng.
+
+Code and data placed in this directory is not required to build libpng,
+however the code in this directory has been used to generate data or code in
+the body of the libpng source.  The source code identifies where this has
+been done.  Code in this directory may not compile on all operating systems
+that libpng supports.
+
+NO COPYRIGHT RIGHTS ARE CLAIMED TO ANY OF THE FILES IN THIS DIRECTORY.
+
+To the extent possible under law, the authors have waived all copyright and
+related or neighboring rights to this work.  This work is published from:
+United States.
+
+The files may be used freely in any way.
+
+The source code and comments in this directory are the original work of the
+people named below.  No other person or organization has made contributions to
+the work in this directory.
+
+ORIGINAL AUTHORS
+    The following people have contributed to the code in this directory.  None
+    of the people below claim any rights with regard to the contents of this
+    directory.
+
+    John Bowler <jbowler at acm.org>
+    Glenn Randers-Pehrson <glennrp at users.sourceforge.net>
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/checksum-icc.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/checksum-icc.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/checksum-icc.c	(revision 107811)
@@ -0,0 +1,100 @@
+/* checksum-icc.c
+ *
+ * Copyright (c) 2013 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Generate crc32 and adler32 checksums of the given input files, used to
+ * generate check-codes for use when matching ICC profiles within libpng.
+ */
+
+#include <stdio.h>
+#include <zlib.h>
+
+static int
+read_one_file(FILE *ip, const char *name)
+{
+   uLong length = 0;
+   uLong a32 = adler32(0, NULL, 0);
+   uLong c32 = crc32(0, NULL, 0);
+   Byte header[132];
+
+   for (;;)
+   {
+      int ch = getc(ip);
+      Byte b;
+
+      if (ch == EOF) break;
+
+      b = (Byte)ch;
+
+      if (length < sizeof header)
+         header[length] = b;
+
+      ++length;
+      a32 = adler32(a32, &b, 1);
+      c32 = crc32(c32, &b, 1);
+   }
+
+   if (ferror(ip))
+      return 0;
+
+   /* Success */
+   printf("PNG_ICC_CHECKSUM(0x%8.8lx, 0x%8.8lx,\n   PNG_MD5("
+      "0x%2.2x%2.2x%2.2x%2.2x, 0x%2.2x%2.2x%2.2x%2.2x, 0x%2.2x%2.2x%2.2x%2.2x,"
+      " 0x%2.2x%2.2x%2.2x%2.2x), %d,\n"
+      "   \"%4.4d/%2.2d/%2.2d %2.2d:%2.2d:%2.2d\", %lu, \"%s\")\n",
+      (unsigned long)a32, (unsigned long)c32,
+      header[84], header[85], header[86], header[87],
+      header[88], header[89], header[90], header[91],
+      header[92], header[93], header[94], header[95],
+      header[96], header[97], header[98], header[99],
+#     define u16(x) (header[x] * 256 + header[x+1])
+#     define u32(x) (u16(x) * 65536 + u16(x+2))
+      u32(64), u16(24), u16(26), u16(28), u16(30), u16(32), u16(34),
+      (unsigned long)length, name);
+
+   return 1;
+}
+
+int main(int argc, char **argv)
+{
+   int err = 0;
+
+   printf("/* adler32, crc32, MD5[16], intent, date, length, file-name */\n");
+
+   if (argc > 1)
+   {
+      int i;
+
+      for (i=1; i<argc; ++i)
+      {
+         FILE *ip = fopen(argv[i], "rb");
+
+         if (ip == NULL || !read_one_file(ip, argv[i]))
+         {
+            err = 1;
+            perror(argv[i]);
+            fprintf(stderr, "%s: read error\n", argv[i]);
+            printf("/* ERROR: %s */\n", argv[i]);
+         }
+
+         (void)fclose(ip);
+      }
+   }
+
+   else
+   {
+      if (!read_one_file(stdin, "-"))
+      {
+         err = 1;
+         perror("stdin");
+         fprintf(stderr, "stdin: read error\n");
+         printf("/* ERROR: stdin */\n");
+      }
+   }
+
+   return err;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/cvtcolor.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/cvtcolor.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/cvtcolor.c	(revision 107811)
@@ -0,0 +1,186 @@
+/* convert.c
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2013.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Convert 8-bit sRGB or 16-bit linear values to another format.
+ */
+
+#define _ISOC99_SOURCE 1
+
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+
+#include <fenv.h>
+
+#include "sRGB.h"
+
+static void
+usage(const char *prog)
+{
+   fprintf(stderr,
+      "%s: usage: %s [-linear|-sRGB] [-gray|-color] component{1,4}\n",
+      prog, prog);
+   exit(1);
+}
+
+unsigned long
+component(const char *prog, const char *arg, int issRGB)
+{
+   char *ep;
+   unsigned long c = strtoul(arg, &ep, 0);
+
+   if (ep <= arg || *ep || c > 65535 || (issRGB && c > 255))
+   {
+      fprintf(stderr, "%s: %s: invalid component value (%lu)\n", prog, arg, c);
+      usage(prog);
+   }
+
+   return c;
+}
+
+int
+main(int argc, const char **argv)
+{
+   const char *prog = *argv++;
+   int to_linear = 0, to_gray = 0, to_color = 0;
+   int channels = 0;
+   double c[4];
+
+   /* FE_TONEAREST is the IEEE754 round to nearest, preferring even, mode; i.e.
+    * everything rounds to the nearest value except that '.5' rounds to the
+    * nearest even value.
+    */
+   fesetround(FE_TONEAREST);
+
+   c[3] = c[2] = c[1] = c[0] = 0;
+
+   while (--argc > 0 && **argv == '-')
+   {
+      const char *arg = 1+*argv++;
+
+      if (strcmp(arg, "sRGB") == 0)
+         to_linear = 0;
+
+      else if (strcmp(arg, "linear") == 0)
+         to_linear = 1;
+
+      else if (strcmp(arg, "gray") == 0)
+         to_gray = 1, to_color = 0;
+
+      else if (strcmp(arg, "color") == 0)
+         to_gray = 0, to_color = 1;
+
+      else
+         usage(prog);
+   }
+
+   switch (argc)
+   {
+      default:
+         usage(prog);
+         break;
+
+      case 4:
+         c[3] = component(prog, argv[3], to_linear);
+         ++channels;
+      case 3:
+         c[2] = component(prog, argv[2], to_linear);
+         ++channels;
+      case 2:
+         c[1] = component(prog, argv[1], to_linear);
+         ++channels;
+      case 1:
+         c[0] = component(prog, argv[0], to_linear);
+         ++channels;
+         break;
+      }
+
+   if (to_linear)
+   {
+      int i;
+      int components = channels;
+
+      if ((components & 1) == 0)
+         --components;
+
+      for (i=0; i<components; ++i) c[i] = linear_from_sRGB(c[i] / 255);
+      if (components < channels)
+         c[components] = c[components] / 255;
+   }
+
+   else
+   {
+      int i;
+      for (i=0; i<4; ++i) c[i] /= 65535;
+
+      if ((channels & 1) == 0)
+      {
+         double alpha = c[channels-1];
+
+         if (alpha > 0)
+            for (i=0; i<channels-1; ++i) c[i] /= alpha;
+         else
+            for (i=0; i<channels-1; ++i) c[i] = 1;
+      }
+   }
+
+   if (to_gray)
+   {
+      if (channels < 3)
+      {
+         fprintf(stderr, "%s: too few channels (%d) for -gray\n",
+            prog, channels);
+         usage(prog);
+      }
+
+      c[0] = YfromRGB(c[0], c[1], c[2]);
+      channels -= 2;
+   }
+
+   if (to_color)
+   {
+      if (channels > 2)
+      {
+         fprintf(stderr, "%s: too many channels (%d) for -color\n",
+            prog, channels);
+         usage(prog);
+      }
+
+      c[3] = c[1]; /* alpha, if present */
+      c[2] = c[1] = c[0];
+   }
+
+   if (to_linear)
+   {
+      int i;
+      if ((channels & 1) == 0)
+      {
+         double alpha = c[channels-1];
+         for (i=0; i<channels-1; ++i) c[i] *= alpha;
+      }
+
+      for (i=0; i<channels; ++i) c[i] = nearbyint(c[i] * 65535);
+   }
+
+   else /* to sRGB */
+   {
+      int i = (channels+1)&~1;
+      while (--i >= 0)
+         c[i] = sRGB_from_linear(c[i]);
+
+      for (i=0; i<channels; ++i) c[i] = nearbyint(c[i] * 255);
+   }
+
+   {
+      int i;
+      for (i=0; i<channels; ++i) printf(" %g", c[i]);
+   }
+   printf("\n");
+
+   return 0;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/genpng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/genpng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/genpng.c	(revision 107811)
@@ -0,0 +1,882 @@
+/* genpng
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2015.
+ * Revised by Glenn Randers-Pehrson, 2017, to add buffer-size check.
+ * To the extent possible under law, the authors have waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Generate a PNG with an alpha channel, correctly.
+ *
+ * This is a test case generator; the resultant PNG files are only of interest
+ * to those of us who care about whether the edges of circles are green, red,
+ * or yellow.
+ *
+ * The program generates an RGB+Alpha PNG of a given size containing the given
+ * shapes on a transparent background:
+ *
+ *  genpng width height { shape }
+ *    shape ::= color width shape x1 y1 x2 y2
+ *
+ * 'color' is:
+ *
+ *  black white red green yellow blue brown purple pink orange gray cyan
+ *
+ * The point is to have colors that are linguistically meaningful plus that old
+ * bugbear of the department store dress murders, Cyan, the only color we argue
+ * about.
+ *
+ * 'shape' is:
+ *
+ *  circle: an ellipse
+ *  square: a rectangle
+ *  line: a straight line
+ *
+ * Each shape is followed by four numbers, these are two points in the output
+ * coordinate space (as real numbers) which describe the circle, square, or
+ * line.  The shape is filled if it is preceded by 'filled' (not valid for
+ * 'line') or is drawn with a line, in which case the width of the line must
+ * precede the shape.
+ *
+ * The whole set of information can be repeated as many times as desired:
+ *
+ *    shape ::= color width shape x1 y1 x2 y2
+ *
+ *    color ::= black|white|red|green|yellow|blue
+ *    color ::= brown|purple|pink|orange|gray|cyan
+ *    width ::= filled
+ *    width ::= <number>
+ *    shape ::= circle|square|line
+ *    x1    ::= <number>
+ *    x2    ::= <number>
+ *    y1    ::= <number>
+ *    y2    ::= <number>
+ *
+ * The output PNG is generated by down-sampling a 4x supersampled image using
+ * a bi-cubic filter.  The bi-cubic has a 2 (output) pixel width, so an 8x8
+ * array of super-sampled points contribute to each output pixel.  The value of
+ * a super-sampled point is found using an unfiltered, aliased, infinite
+ * precision image: Each shape from the last to the first is checked to see if
+ * the point is in the drawn area and, if it is, the color of the point is the
+ * color of the shape and the alpha is 1, if not the previous shape is checked.
+ *
+ * This is an aliased algorithm because no filtering is done; a point is either
+ * inside or outside each shape and 'close' points do not contribute to the
+ * sample.  The down-sampling is relied on to correct the error of not using
+ * a filter.
+ *
+ * The line end-caps are 'flat'; they go through the points.  The square line
+ * joins are mitres; the outside of the lines are continued to the point of
+ * intersection.
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <math.h>
+
+/* Normally use <png.h> here to get the installed libpng, but this is done to
+ * ensure the code picks up the local libpng implementation:
+ */
+#include "../../png.h"
+
+#if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
+
+static const struct color
+{
+   const char *name;
+   double      red;
+   double      green;
+   double      blue;
+} colors[] =
+/* color ::= black|white|red|green|yellow|blue
+ * color ::= brown|purple|pink|orange|gray|cyan
+ */
+{
+   { "black",   0,    0,  0 },
+   { "white",   1,    1,  1 },
+   { "red",     1,    0,  0 },
+   { "green",   0,    1,  0 },
+   { "yellow",  1,    1,  0 },
+   { "blue",    0,    0,  1 },
+   { "brown",  .5, .125,  0 },
+   { "purple",  1,    0,  1 },
+   { "pink",    1,   .5, .5 },
+   { "orange",  1,   .5,  0 },
+   { "gray",    0,   .5, .5 },
+   { "cyan",    0,    1,  1 }
+};
+#define color_count ((sizeof colors)/(sizeof colors[0]))
+
+static const struct color *
+color_of(const char *arg)
+{
+   int icolor = color_count;
+
+   while (--icolor >= 0)
+   {
+      if (strcmp(colors[icolor].name, arg) == 0)
+         return colors+icolor;
+   }
+
+   fprintf(stderr, "genpng: invalid color %s\n", arg);
+   exit(1);
+}
+
+static double
+width_of(const char *arg)
+{
+   if (strcmp(arg, "filled") == 0)
+      return 0;
+
+   else
+   {
+      char *ep = NULL;
+      double w = strtod(arg, &ep);
+
+      if (ep != NULL && *ep == 0 && w > 0)
+         return w;
+   }
+
+   fprintf(stderr, "genpng: invalid line width %s\n", arg);
+   exit(1);
+}
+
+static double
+coordinate_of(const char *arg)
+{
+   char *ep = NULL;
+   double w = strtod(arg, &ep);
+
+   if (ep != NULL && *ep == 0)
+      return w;
+
+   fprintf(stderr, "genpng: invalid coordinate value %s\n", arg);
+   exit(1);
+}
+
+struct arg; /* forward declaration */
+
+typedef int (*shape_fn_ptr)(const struct arg *arg, double x, double y);
+   /* A function to determine if (x,y) is inside the shape.
+    *
+    * There are two implementations:
+    *
+    *    inside_fn: returns true if the point is inside
+    *    check_fn:  returns;
+    *       -1: the point is outside the shape by more than the filter width (2)
+    *        0: the point may be inside the shape
+    *       +1: the point is inside the shape by more than the filter width
+    */
+#define OUTSIDE (-1)
+#define INSIDE  (1)
+
+struct arg
+{
+   const struct color *color;
+   shape_fn_ptr        inside_fn;
+   shape_fn_ptr        check_fn;
+   double              width; /* line width, 0 for 'filled' */
+   double              x1, y1, x2, y2;
+};
+
+/* IMPLEMENTATION NOTE:
+ *
+ * We want the contribution of each shape to the sample corresponding to each
+ * pixel.  This could be obtained by super sampling the image to infinite
+ * dimensions, finding each point within the shape and assigning that a value
+ * '1' while leaving every point outside the shape with value '0' then
+ * downsampling to the image size with sinc; computationally very expensive.
+ *
+ * Approximations are as follows:
+ *
+ * 1) If the pixel coordinate is within the shape assume the sample has the
+ *    shape color and is opaque, else assume there is no contribution from
+ *    the shape.
+ *
+ *    This is the equivalent of aliased rendering or resampling an image with
+ *    a block filter.  The maximum error in the calculated alpha (which will
+ *    always be 0 or 1) is 0.5.
+ *
+ * 2) If the shape is within a square of size 1x1 centered on the pixel assume
+ *    that the shape obscures an amount of the pixel equal to its area within
+ *    that square.
+ *
+ *    This is the equivalent of 'pixel coverage' alpha calculation or resampling
+ *    an image with a bi-linear filter.  The maximum error is over 0.2, but the
+ *    results are often acceptable.
+ *
+ *    This can be approximated by applying (1) to a super-sampled image then
+ *    downsampling with a bi-linear filter.  The error in the super-sampled
+ *    image is 0.5 per sample, but the resampling reduces this.
+ *
+ * 3) Use a better filter with a super-sampled image; in the limit this is the
+ *    sinc() approach.
+ *
+ * 4) Do the geometric calculation; a bivariate definite integral across the
+ *    shape, unfortunately this means evaluating Si(x), the integral of sinc(x),
+ *    which is still a lot of math.
+ *
+ * This code uses approach (3) with a bi-cubic filter and 8x super-sampling
+ * and method (1) for the super-samples.  This means that the sample is either
+ * 0 or 1, depending on whether the sub-pixel is within or outside the shape.
+ * The bi-cubic weights are also fixed and the 16 required weights are
+ * pre-computed here (note that the 'scale' setting will need to be changed if
+ * 'super' is increased).
+ *
+ * The code also calculates a sum to the edge of the filter. This is not
+ * currently used by could be used to optimize the calculation.
+ */
+#if 0 /* bc code */
+scale=10
+super=8
+define bicubic(x) {
+   if (x <= 1) return (1.5*x - 2.5)*x*x + 1;
+   if (x <  2) return (((2.5 - 0.5*x)*x - 4)*x + 2);
+   return 0;
+}
+define sum(x) {
+   auto s;
+   s = 0;
+   while (x < 2*super) {
+      s = s + bicubic(x/super);
+      x = x + 1;
+   }
+   return s;
+}
+define results(x) {
+   auto b, s;
+   b = bicubic(x/super);
+   s = sum(x);
+
+   print "   /*", x, "*/ { ", b, ", ", s, " }";
+   return 1;
+}
+x=0
+while (x<2*super) {
+   x = x + results(x)
+   if (x < 2*super) print ","
+   print "\n"
+}
+quit
+#endif
+
+#define BICUBIC1(x) /*     |x| <= 1 */ ((1.5*(x)* - 2.5)*(x)*(x) + 1)
+#define BICUBIC2(x) /* 1 < |x| <  2 */ (((2.5 - 0.5*(x))*(x) - 4)*(x) + 2)
+#define FILTER_WEIGHT 9 /* Twice the first sum below */
+#define FILTER_WIDTH  2 /* Actually half the width; -2..+2 */
+#define FILTER_STEPS  8 /* steps per filter unit */
+static const double
+bicubic[16][2] =
+{
+   /* These numbers are exact; the weight for the filter is 1/9, but this
+    * would make the numbers inexact, so it is not included here.
+    */
+   /*          bicubic      sum        */
+   /* 0*/ { 1.0000000000, 4.5000000000 },
+   /* 1*/ {  .9638671875, 3.5000000000 },
+   /* 2*/ {  .8671875000, 2.5361328125 },
+   /* 3*/ {  .7275390625, 1.6689453125 },
+   /* 4*/ {  .5625000000,  .9414062500 },
+   /* 5*/ {  .3896484375,  .3789062500 },
+   /* 6*/ {  .2265625000, -.0107421875 },
+   /* 7*/ {  .0908203125, -.2373046875 },
+   /* 8*/ {            0, -.3281250000 },
+   /* 9*/ { -.0478515625, -.3281250000 },
+   /*10*/ { -.0703125000, -.2802734375 },
+   /*11*/ { -.0732421875, -.2099609375 },
+   /*12*/ { -.0625000000, -.1367187500 },
+   /*13*/ { -.0439453125, -.0742187500 },
+   /*14*/ { -.0234375000, -.0302734375 },
+   /*15*/ { -.0068359375, -.0068359375 }
+};
+
+static double
+alpha_calc(const struct arg *arg, double x, double y)
+{
+   /* For [x-2..x+2],[y-2,y+2] calculate the weighted bicubic given a function
+    * which tells us whether a point is inside or outside the shape.  First
+    * check if we need to do this at all:
+    */
+   switch (arg->check_fn(arg, x, y))
+   {
+      case OUTSIDE:
+         return 0; /* all samples outside the shape */
+
+      case INSIDE:
+         return 1; /* all samples inside the shape */
+
+      default:
+      {
+         int dy;
+         double alpha = 0;
+
+#        define FILTER_D (FILTER_WIDTH*FILTER_STEPS-1)
+         for (dy=-FILTER_D; dy<=FILTER_D; ++dy)
+         {
+            double wy = bicubic[abs(dy)][0];
+
+            if (wy != 0)
+            {
+               double alphay = 0;
+               int dx;
+
+               for (dx=-FILTER_D; dx<=FILTER_D; ++dx)
+               {
+                  double wx = bicubic[abs(dx)][0];
+
+                  if (wx != 0 && arg->inside_fn(arg, x+dx/16, y+dy/16))
+                     alphay += wx;
+               }
+
+               alpha += wy * alphay;
+            }
+         }
+
+         /* This needs to be weighted for each dimension: */
+         return alpha / (FILTER_WEIGHT*FILTER_WEIGHT);
+      }
+   }
+}
+
+/* These are the shape functions. */
+/* "square",
+ * { inside_square_filled, check_square_filled },
+ * { inside_square, check_square }
+ */
+static int
+square_check(double x, double y, double x1, double y1, double x2, double y2)
+   /* Is x,y inside the square (x1,y1)..(x2,y2)? */
+{
+   /* Do a modified Cohen-Sutherland on one point, bit patterns that indicate
+    * 'outside' are:
+    *
+    *   x<x1 | x<y1 | x<x2 | x<y2
+    *    0      x      0      x     To the right
+    *    1      x      1      x     To the left
+    *    x      0      x      0     Below
+    *    x      1      x      1     Above
+    *
+    * So 'inside' is (x<x1) != (x<x2) && (y<y1) != (y<y2);
+    */
+   return ((x<x1) ^ (x<x2)) & ((y<y1) ^ (y<y2));
+}
+
+static int
+inside_square_filled(const struct arg *arg, double x, double y)
+{
+   return square_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2);
+}
+
+static int
+square_check_line(const struct arg *arg, double x, double y, double w)
+   /* Check for a point being inside the boundaries implied by the given arg
+    * and assuming a width 2*w each side of the boundaries.  This returns the
+    * 'check' INSIDE/OUTSIDE/0 result but note the semantics:
+    *
+    *          +--------------+
+    *          |              |   OUTSIDE
+    *          |   INSIDE     |
+    *          |              |
+    *          +--------------+
+    *
+    * And '0' means within the line boundaries.
+    */
+{
+   double cx = (arg->x1+arg->x2)/2;
+   double wx = fabs(arg->x1-arg->x2)/2;
+   double cy = (arg->y1+arg->y2)/2;
+   double wy = fabs(arg->y1-arg->y2)/2;
+
+   if (square_check(x, y, cx-wx-w, cy-wy-w, cx+wx+w, cy+wy+w))
+   {
+      /* Inside, but maybe too far; check for the redundant case where
+       * the lines overlap:
+       */
+      wx -= w;
+      wy -= w;
+      if (wx > 0 && wy > 0 && square_check(x, y, cx-wx, cy-wy, cx+wx, cy+wy))
+         return INSIDE; /* between (inside) the boundary lines. */
+
+      return 0; /* inside the lines themselves. */
+   }
+
+   return OUTSIDE; /* outside the boundary lines. */
+}
+
+static int
+check_square_filled(const struct arg *arg, double x, double y)
+{
+   /* The filter extends +/-FILTER_WIDTH each side of each output point, so
+    * the check has to expand and contract the square by that amount; '0'
+    * means close enough to the edge of the square that the bicubic filter has
+    * to be run, OUTSIDE means alpha==0, INSIDE means alpha==1.
+    */
+   return square_check_line(arg, x, y, FILTER_WIDTH);
+}
+
+static int
+inside_square(const struct arg *arg, double x, double y)
+{
+   /* Return true if within the drawn lines, else false, no need to distinguish
+    * INSIDE vs OUTSIDE here:
+    */
+   return square_check_line(arg, x, y, arg->width/2) == 0;
+}
+
+static int
+check_square(const struct arg *arg, double x, double y)
+{
+   /* So for this function a result of 'INSIDE' means inside the actual lines.
+    */
+   double w = arg->width/2;
+
+   if (square_check_line(arg, x, y, w+FILTER_WIDTH) == 0)
+   {
+      /* Somewhere close to the boundary lines. If far enough inside one of
+       * them then we can return INSIDE:
+       */
+      w -= FILTER_WIDTH;
+
+      if (w > 0 && square_check_line(arg, x, y, w) == 0)
+         return INSIDE;
+
+      /* Point is somewhere in the filter region: */
+      return 0;
+   }
+
+   else /* Inside or outside the square by more than w+FILTER_WIDTH. */
+      return OUTSIDE;
+}
+
+/* "circle",
+ * { inside_circle_filled, check_circle_filled },
+ * { inside_circle, check_circle }
+ *
+ * The functions here are analogous to the square ones; however, they check
+ * the corresponding ellipse as opposed to the rectangle.
+ */
+static int
+circle_check(double x, double y, double x1, double y1, double x2, double y2)
+{
+   if (square_check(x, y, x1, y1, x2, y2))
+   {
+      /* Inside the square, so maybe inside the circle too: */
+      const double cx = (x1 + x2)/2;
+      const double cy = (y1 + y2)/2;
+      const double dx = x1 - x2;
+      const double dy = y1 - y2;
+
+      x = (x - cx)/dx;
+      y = (y - cy)/dy;
+
+      /* It is outside if the distance from the center is more than half the
+       * diameter:
+       */
+      return x*x+y*y < .25;
+   }
+
+   return 0; /* outside */
+}
+
+static int
+inside_circle_filled(const struct arg *arg, double x, double y)
+{
+   return circle_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2);
+}
+
+static int
+circle_check_line(const struct arg *arg, double x, double y, double w)
+   /* Check for a point being inside the boundaries implied by the given arg
+    * and assuming a width 2*w each side of the boundaries.  This function has
+    * the same semantic as square_check_line but tests the circle.
+    */
+{
+   double cx = (arg->x1+arg->x2)/2;
+   double wx = fabs(arg->x1-arg->x2)/2;
+   double cy = (arg->y1+arg->y2)/2;
+   double wy = fabs(arg->y1-arg->y2)/2;
+
+   if (circle_check(x, y, cx-wx-w, cy-wy-w, cx+wx+w, cy+wy+w))
+   {
+      /* Inside, but maybe too far; check for the redundant case where
+       * the lines overlap:
+       */
+      wx -= w;
+      wy -= w;
+      if (wx > 0 && wy > 0 && circle_check(x, y, cx-wx, cy-wy, cx+wx, cy+wy))
+         return INSIDE; /* between (inside) the boundary lines. */
+
+      return 0; /* inside the lines themselves. */
+   }
+
+   return OUTSIDE; /* outside the boundary lines. */
+}
+
+static int
+check_circle_filled(const struct arg *arg, double x, double y)
+{
+   return circle_check_line(arg, x, y, FILTER_WIDTH);
+}
+
+static int
+inside_circle(const struct arg *arg, double x, double y)
+{
+   return circle_check_line(arg, x, y, arg->width/2) == 0;
+}
+
+static int
+check_circle(const struct arg *arg, double x, double y)
+{
+   /* Exactly as the 'square' code.  */
+   double w = arg->width/2;
+
+   if (circle_check_line(arg, x, y, w+FILTER_WIDTH) == 0)
+   {
+      w -= FILTER_WIDTH;
+
+      if (w > 0 && circle_check_line(arg, x, y, w) == 0)
+         return INSIDE;
+
+      /* Point is somewhere in the filter region: */
+      return 0;
+   }
+
+   else /* Inside or outside the square by more than w+FILTER_WIDTH. */
+      return OUTSIDE;
+}
+
+/* "line",
+ * { NULL, NULL },  There is no 'filled' line.
+ * { inside_line, check_line }
+ */
+static int
+line_check(double x, double y, double x1, double y1, double x2, double y2,
+   double w, double expand)
+{
+   /* Shift all the points to (arg->x1, arg->y1) */
+   double lx = x2 - x1;
+   double ly = y2 - y1;
+   double len2 = lx*lx + ly*ly;
+   double cross, dot;
+
+   x -= x1;
+   y -= y1;
+
+   /* The dot product is the distance down the line, the cross product is
+    * the distance away from the line:
+    *
+    *    distance = |cross| / sqrt(len2)
+    */
+   cross = x * ly - y * lx;
+
+   /* If 'distance' is more than w the point is definitely outside the line:
+    *
+    *     distance >= w
+    *     |cross|  >= w * sqrt(len2)
+    *     cross^2  >= w^2 * len2:
+    */
+   if (cross*cross >= (w+expand)*(w+expand)*len2)
+      return 0; /* outside */
+
+   /* Now find the distance *along* the line; this comes from the dot product
+    * lx.x+ly.y. The actual distance (in pixels) is:
+    *
+    *   distance = dot / sqrt(len2)
+    */
+   dot = lx * x + ly * y;
+
+   /* The test for 'outside' is:
+    *
+    *    distance < 0 || distance > sqrt(len2)
+    *                 -> dot / sqrt(len2) > sqrt(len2)
+    *                 -> dot > len2
+    *
+    * But 'expand' is used for the filter width and needs to be handled too:
+    */
+   return dot > -expand && dot < len2+expand;
+}
+
+static int
+inside_line(const struct arg *arg, double x, double y)
+{
+   return line_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2, arg->width/2, 0);
+}
+
+static int
+check_line(const struct arg *arg, double x, double y)
+{
+   /* The end caps of the line must be checked too; it's not enough just to
+    * widen the line by FILTER_WIDTH; 'expand' exists for this purpose:
+    */
+   if (line_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2, arg->width/2,
+       FILTER_WIDTH))
+   {
+      /* Inside the line+filter; far enough inside that the filter isn't
+       * required?
+       */
+      if (arg->width > 2*FILTER_WIDTH &&
+          line_check(x, y, arg->x1, arg->y1, arg->x2, arg->y2, arg->width/2,
+             -FILTER_WIDTH))
+         return INSIDE;
+
+      return 0;
+   }
+
+   return OUTSIDE;
+}
+
+static const struct
+{
+   const char    *name;
+   shape_fn_ptr   function[2/*fill,line*/][2];
+#  define         FN_INSIDE 0
+#  define         FN_CHECK 1
+} shape_defs[] =
+{
+   {  "square",
+      {  { inside_square_filled, check_square_filled },
+         { inside_square, check_square } }
+   },
+   {  "circle",
+      {  { inside_circle_filled, check_circle_filled },
+         { inside_circle, check_circle } }
+   },
+   {  "line",
+      {  { NULL, NULL },
+         { inside_line, check_line } }
+   }
+};
+
+#define shape_count ((sizeof shape_defs)/(sizeof shape_defs[0]))
+
+static shape_fn_ptr
+shape_of(const char *arg, double width, int f)
+{
+   unsigned int i;
+
+   for (i=0; i<shape_count; ++i) if (strcmp(shape_defs[i].name, arg) == 0)
+   {
+      shape_fn_ptr fn = shape_defs[i].function[width != 0][f];
+
+      if (fn != NULL)
+         return fn;
+
+      fprintf(stderr, "genpng: %s %s not supported\n",
+         width == 0 ? "filled" : "unfilled", arg);
+      exit(1);
+   }
+
+   fprintf(stderr, "genpng: %s: not a valid shape name\n", arg);
+   exit(1);
+}
+
+static void
+parse_arg(struct arg *arg, const char **argv/*7 arguments*/)
+{
+   /* shape ::= color width shape x1 y1 x2 y2 */
+   arg->color = color_of(argv[0]);
+   arg->width = width_of(argv[1]);
+   arg->inside_fn = shape_of(argv[2], arg->width, FN_INSIDE);
+   arg->check_fn = shape_of(argv[2], arg->width, FN_CHECK);
+   arg->x1 = coordinate_of(argv[3]);
+   arg->y1 = coordinate_of(argv[4]);
+   arg->x2 = coordinate_of(argv[5]);
+   arg->y2 = coordinate_of(argv[6]);
+}
+
+static png_uint_32
+read_wh(const char *name, const char *str)
+   /* read a PNG width or height */
+{
+   char *ep = NULL;
+   unsigned long ul = strtoul(str, &ep, 10);
+
+   if (ep != NULL && *ep == 0 && ul > 0 && ul <= 0x7fffffff)
+      return (png_uint_32)/*SAFE*/ul;
+
+   fprintf(stderr, "genpng: %s: invalid number %s\n", name, str);
+   exit(1);
+}
+
+static void
+pixel(png_uint_16p p, struct arg *args, int nargs, double x, double y)
+{
+   /* Fill in the pixel by checking each shape (args[nargs]) for effects on
+    * the corresponding sample:
+    */
+   double r=0, g=0, b=0, a=0;
+
+   while (--nargs >= 0 && a != 1)
+   {
+      /* NOTE: alpha_calc can return a value outside the range 0..1 with the
+       * bicubic filter.
+       */
+      const double alpha = alpha_calc(args+nargs, x, y) * (1-a);
+
+      r += alpha * args[nargs].color->red;
+      g += alpha * args[nargs].color->green;
+      b += alpha * args[nargs].color->blue;
+      a += alpha;
+   }
+
+   /* 'a' may be negative or greater than 1; if it is, negative clamp the
+    * pixel to 0 if >1 clamp r/g/b:
+    */
+   if (a > 0)
+   {
+      if (a > 1)
+      {
+         if (r > 1) r = 1;
+         if (g > 1) g = 1;
+         if (b > 1) b = 1;
+         a = 1;
+      }
+
+      /* And fill in the pixel: */
+      p[0] = (png_uint_16)/*SAFE*/round(r * 65535);
+      p[1] = (png_uint_16)/*SAFE*/round(g * 65535);
+      p[2] = (png_uint_16)/*SAFE*/round(b * 65535);
+      p[3] = (png_uint_16)/*SAFE*/round(a * 65535);
+   }
+
+   else
+      p[3] = p[2] = p[1] = p[0] = 0;
+}
+
+int
+main(int argc, const char **argv)
+{
+   int convert_to_8bit = 0;
+
+   /* There is one option: --8bit: */
+   if (argc > 1 && strcmp(argv[1], "--8bit") == 0)
+      --argc, ++argv, convert_to_8bit = 1;
+
+   if (argc >= 3)
+   {
+      png_uint_16p buffer;
+      int nshapes;
+      png_image image;
+#     define max_shapes 256
+      struct arg arg_list[max_shapes];
+
+      /* The libpng Simplified API write code requires a fully initialized
+       * structure.
+       */
+      memset(&image, 0, sizeof image);
+      image.version = PNG_IMAGE_VERSION;
+      image.opaque = NULL;
+      image.width = read_wh("width", argv[1]);
+      image.height = read_wh("height", argv[2]);
+      image.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
+      image.flags = 0;
+      image.colormap_entries = 0;
+
+      /* Check the remainder of the arguments */
+      for (nshapes=0; 3+7*(nshapes+1) <= argc && nshapes < max_shapes;
+           ++nshapes)
+         parse_arg(arg_list+nshapes, argv+3+7*nshapes);
+
+      if (3+7*nshapes != argc)
+      {
+         fprintf(stderr, "genpng: %s: too many arguments\n", argv[3+7*nshapes]);
+         return 1;
+      }
+
+#if 1
+     /* TO do: determine whether this guard against overflow is necessary.
+      * This comment in png.h indicates that it should be safe: "libpng will
+      * refuse to process an image where such an overflow would occur", but
+      * I don't see where the image gets rejected when the buffer is too
+      * large before the malloc is attempted.
+      */
+      if (image.height > ((size_t)(-1))/(8*image.width)) {
+         fprintf(stderr, "genpng: image buffer would be too big");
+         return 1;
+      }
+#endif
+
+      /* Create the buffer: */
+      buffer = malloc(PNG_IMAGE_SIZE(image));
+
+      if (buffer != NULL)
+      {
+         png_uint_32 y;
+
+         /* Write each row... */
+         for (y=0; y<image.height; ++y)
+         {
+            png_uint_32 x;
+
+            /* Each pixel in each row: */
+            for (x=0; x<image.width; ++x)
+               pixel(buffer + 4*(x + y*image.width), arg_list, nshapes, x, y);
+         }
+
+         /* Write the result (to stdout) */
+         if (png_image_write_to_stdio(&image, stdout, convert_to_8bit,
+             buffer, 0/*row_stride*/, NULL/*colormap*/))
+         {
+            free(buffer);
+            return 0; /* success */
+         }
+
+         else
+            fprintf(stderr, "genpng: write stdout: %s\n", image.message);
+
+         free(buffer);
+      }
+
+      else
+         fprintf(stderr, "genpng: out of memory: %lu bytes\n",
+               (unsigned long)PNG_IMAGE_SIZE(image));
+   }
+
+   else
+   {
+      /* Wrong number of arguments */
+      fprintf(stderr, "genpng: usage: genpng [--8bit] width height {shape}\n"
+         " Generate a transparent PNG in RGBA (truecolor+alpha) format\n"
+         " containing the given shape or shapes.  Shapes are defined:\n"
+         "\n"
+         "  shape ::= color width shape x1 y1 x2 y2\n"
+         "  color ::= black|white|red|green|yellow|blue\n"
+         "  color ::= brown|purple|pink|orange|gray|cyan\n"
+         "  width ::= filled|<number>\n"
+         "  shape ::= circle|square|line\n"
+         "  x1,x2 ::= <number>\n"
+         "  y1,y2 ::= <number>\n"
+         "\n"
+         " Numbers are floating point numbers describing points relative to\n"
+         " the top left of the output PNG as pixel coordinates.  The 'width'\n"
+         " parameter is either the width of the line (in output pixels) used\n"
+         " to draw the shape or 'filled' to indicate that the shape should\n"
+         " be filled with the color.\n"
+         "\n"
+         " Colors are interpreted loosely to give access to the eight full\n"
+         " intensity RGB values:\n"
+         "\n"
+         "  black, red, green, blue, yellow, cyan, purple, white,\n"
+         "\n"
+         " Cyan is full intensity blue+green; RGB(0,1,1), plus the following\n"
+         " lower intensity values:\n"
+         "\n"
+         "  brown:  red+orange:  RGB(0.5, 0.125, 0) (dark red+orange)\n"
+         "  pink:   red+white:   RGB(1.0, 0.5,   0.5)\n"
+         "  orange: red+yellow:  RGB(1.0, 0.5,   0)\n"
+         "  gray:   black+white: RGB(0.5, 0.5,   0.5)\n"
+         "\n"
+         " The RGB values are selected to make detection of aliasing errors\n"
+         " easy. The names are selected to make the description of errors\n"
+         " easy.\n"
+         "\n"
+         " The PNG is written to stdout, if --8bit is given a 32bpp RGBA sRGB\n"
+         " file is produced, otherwise a 64bpp RGBA linear encoded file is\n"
+         " written.\n");
+   }
+
+   return 1;
+}
+#endif /* SIMPLIFIED_WRITE && STDIO */
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/intgamma.sh
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/intgamma.sh	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/intgamma.sh	(revision 107811)
@@ -0,0 +1,108 @@
+#!/bin/sh
+
+# intgamma.sh
+#
+# COPYRIGHT: Written by John Cunningham Bowler, 2013.
+# To the extent possible under law, the author has waived all copyright and
+# related or neighboring rights to this work.  The author published this work
+# from the United States.
+#
+# Shell script to generate png.c 8-bit and 16-bit log tables (see the code in
+# png.c for details).
+#
+# This script uses the "bc" arbitrary precision calculator to calculate 32-bit
+# fixed point values of logarithms appropriate to finding the log of an 8-bit
+# (0..255) value and a similar table for the exponent calculation.
+#
+# "bc" must be on the path when the script is executed, and the math library
+# (-lm) must be available.
+
+# Function to print out a list of numbers as integers; the function truncates
+# the integers which must be one-per-line.
+print(){
+   awk 'BEGIN{
+      str = ""
+   }
+   {
+      sub("\\.[0-9]*$", "")
+      if ($0 == "")
+         $0 = "0"
+
+      if (str == "")
+         t = "   " $0 "U"
+      else
+         t = str ", " $0 "U"
+
+      if (length(t) >= 80) {
+         print str ","
+         str = "   " $0 "U"
+      } else
+         str = t
+   }
+   END{
+      print str
+   }'
+}
+#
+# The logarithm table.
+cat <<END
+/* 8-bit log table: png_8bit_l2[128]
+ * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
+ * 255, so it's the base 2 logarithm of a normalized 8-bit floating point
+ * mantissa.  The numbers are 32-bit fractions.
+ */
+static const png_uint_32
+png_8bit_l2[128] =
+{
+END
+#
+bc -lqws <<END | print
+f=65536*65536/l(2)
+for (i=128;i<256;++i) { .5 - l(i/255)*f; }
+END
+echo '};'
+echo
+#
+# The exponent table.
+cat <<END
+/* The 'exp()' case must invert the above, taking a 20-bit fixed point
+ * logarithmic value and returning a 16 or 8-bit number as appropriate.  In
+ * each case only the low 16 bits are relevant - the fraction - since the
+ * integer bits (the top 4) simply determine a shift.
+ *
+ * The worst case is the 16-bit distinction between 65535 and 65534; this
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
+ * distinguish log2(65535/65534.5) - 10^-5 or 17 bits.  There is little chance
+ * of getting this accuracy in practice.
+ *
+ * To deal with this the following exp() function works out the exponent of the
+ * frational part of the logarithm by using an accurate 32-bit value from the
+ * top four fractional bits then multiplying in the remaining bits.
+ */
+static const png_uint_32
+png_32bit_exp[16] =
+{
+END
+#
+bc -lqws <<END | print
+f=l(2)/16
+for (i=0;i<16;++i) {
+   x = .5 + e(-i*f)*2^32;
+   if (x >= 2^32) x = 2^32-1;
+   x;
+}
+END
+echo '};'
+echo
+#
+# And the table of adjustment values.
+cat <<END
+/* Adjustment table; provided to explain the numbers in the code below. */
+#if 0
+END
+bc -lqws <<END | awk '{ printf "%5d %s\n", 12-NR, $0 }'
+for (i=11;i>=0;--i){
+   (1 - e(-(2^i)/65536*l(2))) * 2^(32-i)
+}
+END
+echo '#endif'
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/makesRGB.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/makesRGB.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/makesRGB.c	(revision 107811)
@@ -0,0 +1,429 @@
+/* makesRGB.c -- build sRGB-to-linear and linear-to-sRGB conversion tables
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2013.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Make a table to convert 8-bit sRGB encoding values into the closest 16-bit
+ * linear value.
+ *
+ * Make two tables to take a linear value scaled to 255*65535 and return an
+ * approximation to the 8-bit sRGB encoded value.  Calculate the error in these
+ * tables and display it.
+ */
+
+#define _C99_SOURCE 1
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+
+/* pngpriv.h includes the definition of 'PNG_sRGB_FROM_LINEAR' which is required
+ * to verify the actual code.
+ */
+#include "../../pngpriv.h"
+
+#include "sRGB.h"
+
+/* The tables are declared 'const' in pngpriv.h, so this redefines the tables to
+ * be used.
+ */
+#define png_sRGB_table sRGB_table
+#define png_sRGB_base sRGB_base
+#define png_sRGB_delta sRGB_delta
+
+static png_uint_16 png_sRGB_table[256];
+static png_uint_16 png_sRGB_base[512];
+static png_byte png_sRGB_delta[512];
+
+static const unsigned int max_input = 255*65535;
+
+double
+fsRGB(double l)
+{
+   return sRGB_from_linear(l/max_input);
+}
+
+double
+sRGB(unsigned int i)
+{
+   return fsRGB(i);
+}
+
+double
+finvsRGB(unsigned int i)
+{
+   return 65535 * linear_from_sRGB(i/255.);
+}
+
+png_uint_16
+invsRGB(unsigned int i)
+{
+   unsigned int x = nearbyint(finvsRGB(i));
+
+   if (x > 65535)
+   {
+      fprintf(stderr, "invsRGB(%u) overflows to %u\n", i, x);
+      exit(1);
+   }
+
+   return (png_uint_16)x;
+}
+
+int
+main(int argc, char **argv)
+{
+   unsigned int i, i16, ibase;
+   double min_error = 0;
+   double max_error = 0;
+   double min_error16 = 0;
+   double max_error16 = 0;
+   double adjust;
+   double adjust_lo = 0.4, adjust_hi = 0.6, adjust_mid = 0.5;
+   unsigned int ec_lo = 0, ec_hi = 0, ec_mid = 0;
+   unsigned int error_count = 0;
+   unsigned int error_count16 = 0;
+   int test_only = 0;
+
+   if (argc > 1)
+      test_only = strcmp("--test", argv[1]) == 0;
+
+   /* Initialize the encoding table first. */
+   for (i=0; i<256; ++i)
+   {
+      png_sRGB_table[i] = invsRGB(i);
+   }
+
+   /* Now work out the decoding tables (this is where the error comes in because
+    * there are 512 set points and 512 straight lines between them.)
+    */
+   for (;;)
+   {
+      if (ec_lo == 0)
+         adjust = adjust_lo;
+
+      else if (ec_hi == 0)
+         adjust = adjust_hi;
+
+      else if (ec_mid == 0)
+         adjust = adjust_mid;
+
+      else if (ec_mid < ec_hi)
+         adjust = (adjust_mid + adjust_hi)/2;
+
+      else if (ec_mid < ec_lo)
+         adjust = (adjust_mid + adjust_lo)/2;
+
+      else
+      {
+         fprintf(stderr, "not reached: %u .. %u .. %u\n", ec_lo, ec_mid, ec_hi);
+         exit(1);
+      }
+
+      /* Calculate the table using the current 'adjust' */
+      for (i=0; i<=511; ++i)
+      {
+         double lo = 255 * sRGB(i << 15);
+         double hi = 255 * sRGB((i+1) << 15);
+         unsigned int calc;
+
+         calc = nearbyint((lo+adjust) * 256);
+         if (calc > 65535)
+         {
+            fprintf(stderr, "table[%d][0]: overflow %08x (%d)\n", i, calc,
+               calc);
+            exit(1);
+         }
+         png_sRGB_base[i] = calc;
+
+         calc = nearbyint((hi-lo) * 32);
+         if (calc > 255)
+         {
+            fprintf(stderr, "table[%d][1]: overflow %08x (%d)\n", i, calc,
+               calc);
+            exit(1);
+         }
+         png_sRGB_delta[i] = calc;
+      }
+
+      /* Check the 16-bit linear values alone: */
+      error_count16 = 0;
+      for (i16=0; i16 <= 65535; ++i16)
+      {
+         unsigned int i = 255*i16;
+         unsigned int iexact = nearbyint(255*sRGB(i));
+         unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+         if (icalc != iexact)
+            ++error_count16;
+      }
+
+      /* Now try changing the adjustment. */
+      if (ec_lo == 0)
+         ec_lo = error_count16;
+
+      else if (ec_hi == 0)
+         ec_hi = error_count16;
+
+      else if (ec_mid == 0)
+      {
+         ec_mid = error_count16;
+         printf("/* initial error counts: %u .. %u .. %u */\n", ec_lo, ec_mid,
+            ec_hi);
+      }
+
+      else if (error_count16 < ec_mid)
+      {
+         printf("/* adjust (mid ): %f: %u -> %u */\n", adjust, ec_mid,
+            error_count16);
+         ec_mid = error_count16;
+         adjust_mid = adjust;
+      }
+
+      else if (adjust < adjust_mid && error_count16 < ec_lo)
+      {
+         printf("/* adjust (low ): %f: %u -> %u */\n", adjust, ec_lo,
+            error_count16);
+         ec_lo = error_count16;
+         adjust_lo = adjust;
+      }
+
+      else if (adjust > adjust_mid && error_count16 < ec_hi)
+      {
+         printf("/* adjust (high): %f: %u -> %u */\n", adjust, ec_hi,
+            error_count16);
+         ec_hi = error_count16;
+         adjust_hi = adjust;
+      }
+
+      else
+      {
+         adjust = adjust_mid;
+         printf("/* adjust: %f: %u */\n", adjust, ec_mid);
+         break;
+      }
+   }
+
+   /* For each entry in the table try to adjust it to minimize the error count
+    * in that entry.  Each entry corresponds to 128 input values.
+    */
+   for (ibase=0; ibase<65536; ibase+=128)
+   {
+      png_uint_16 base = png_sRGB_base[ibase >> 7], trybase = base, ob=base;
+      png_byte delta = png_sRGB_delta[ibase >> 7], trydelta = delta, od=delta;
+      unsigned int ecbase = 0, eco;
+
+      for (;;)
+      {
+         png_sRGB_base[ibase >> 7] = trybase;
+         png_sRGB_delta[ibase >> 7] = trydelta;
+
+         /* Check the 16-bit linear values alone: */
+         error_count16 = 0;
+         for (i16=ibase; i16 < ibase+128; ++i16)
+         {
+            unsigned int i = 255*i16;
+            unsigned int iexact = nearbyint(255*sRGB(i));
+            unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+            if (icalc != iexact)
+               ++error_count16;
+         }
+
+         if (error_count16 == 0)
+            break;
+
+         if (ecbase == 0)
+         {
+            eco = ecbase = error_count16;
+            ++trybase; /* First test */
+         }
+
+         else if (error_count16 < ecbase)
+         {
+            if (trybase > base)
+            {
+               base = trybase;
+               ++trybase;
+            }
+            else if (trybase < base)
+            {
+               base = trybase;
+               --trybase;
+            }
+            else if (trydelta > delta)
+            {
+               delta = trydelta;
+               ++trydelta;
+            }
+            else if (trydelta < delta)
+            {
+               delta = trydelta;
+               --trydelta;
+            }
+            else
+            {
+               fprintf(stderr, "makesRGB: impossible\n");
+               exit(1);
+            }
+            ecbase = error_count16;
+         }
+
+         else
+         {
+            if (trybase > base)
+               trybase = base-1;
+            else if (trybase < base)
+            {
+               trybase = base;
+               ++trydelta;
+            }
+            else if (trydelta > delta)
+               trydelta = delta-1;
+            else if (trydelta < delta)
+               break; /* end of tests */
+         }
+      }
+
+      png_sRGB_base[ibase >> 7] = base;
+      png_sRGB_delta[ibase >> 7] = delta;
+      if (base != ob || delta != od)
+      {
+         printf("/* table[%u]={%u,%u} -> {%u,%u} %u -> %u errors */\n",
+            ibase>>7, ob, od, base, delta, eco, ecbase);
+      }
+      else if (0)
+         printf("/* table[%u]={%u,%u} %u errors */\n", ibase>>7, ob, od,
+            ecbase);
+   }
+
+   /* Only do the full (slow) test at the end: */
+   min_error = -.4999;
+   max_error = .4999;
+   error_count = 0;
+
+   for (i=0; i <= max_input; ++i)
+   {
+      unsigned int iexact = nearbyint(255*sRGB(i));
+      unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+      if (icalc != iexact)
+      {
+         double err = 255*sRGB(i) - icalc;
+
+         if (err > (max_error+.001) || err < (min_error-.001))
+         {
+            printf(
+               "/* 0x%08x: exact: %3d, got: %3d [tables: %08x, %08x] (%f) */\n",
+               i, iexact, icalc, png_sRGB_base[i>>15],
+               png_sRGB_delta[i>>15], err);
+         }
+
+         ++error_count;
+         if (err > max_error)
+            max_error = err;
+         else if (err < min_error)
+            min_error = err;
+      }
+   }
+
+   /* Re-check the 16-bit cases too, including the warning if there is an error
+    * bigger than 1.
+    */
+   error_count16 = 0;
+   max_error16 = 0;
+   min_error16 = 0;
+   for (i16=0; i16 <= 65535; ++i16)
+   {
+      unsigned int i = 255*i16;
+      unsigned int iexact = nearbyint(255*sRGB(i));
+      unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+      if (icalc != iexact)
+      {
+         double err = 255*sRGB(i) - icalc;
+
+         ++error_count16;
+         if (err > max_error16)
+            max_error16 = err;
+         else if (err < min_error16)
+            min_error16 = err;
+
+         if (abs(icalc - iexact) > 1)
+            printf(
+               "/* 0x%04x: exact: %3d, got: %3d [tables: %08x, %08x] (%f) */\n",
+               i16, iexact, icalc, png_sRGB_base[i>>15],
+               png_sRGB_delta[i>>15], err);
+      }
+   }
+
+   /* Check the round trip for each 8-bit sRGB value. */
+   for (i16=0; i16 <= 255; ++i16)
+   {
+      unsigned int i = 255 * png_sRGB_table[i16];
+      unsigned int iexact = nearbyint(255*sRGB(i));
+      unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
+
+      if (i16 != iexact)
+      {
+         fprintf(stderr, "8-bit rounding error: %d -> %d\n", i16, iexact);
+         exit(1);
+      }
+
+      if (icalc != i16)
+      {
+         double finv = finvsRGB(i16);
+
+         printf("/* 8-bit roundtrip error: %d -> %f -> %d(%f) */\n",
+            i16, finv, icalc, fsRGB(255*finv));
+      }
+   }
+
+
+   printf("/* error: %g - %g, %u (%g%%) of readings inexact */\n",
+      min_error, max_error, error_count, (100.*error_count)/max_input);
+   printf("/* 16-bit error: %g - %g, %u (%g%%) of readings inexact */\n",
+      min_error16, max_error16, error_count16, (100.*error_count16)/65535);
+
+   if (!test_only)
+   {
+      printf("const png_uint_16 png_sRGB_table[256] =\n{\n   ");
+      for (i=0; i<255; )
+      {
+         do
+         {
+            printf("%d,", png_sRGB_table[i++]);
+         }
+         while ((i & 0x7) != 0 && i<255);
+         if (i<255) printf("\n   ");
+      }
+      printf("%d\n};\n\n", png_sRGB_table[i]);
+
+
+      printf("const png_uint_16 png_sRGB_base[512] =\n{\n   ");
+      for (i=0; i<511; )
+      {
+         do
+         {
+            printf("%d,", png_sRGB_base[i++]);
+         }
+         while ((i & 0x7) != 0 && i<511);
+         if (i<511) printf("\n   ");
+      }
+      printf("%d\n};\n\n", png_sRGB_base[i]);
+
+      printf("const png_byte png_sRGB_delta[512] =\n{\n   ");
+      for (i=0; i<511; )
+      {
+         do
+         {
+            printf("%d,", png_sRGB_delta[i++]);
+         }
+         while ((i & 0xf) != 0 && i<511);
+         if (i<511) printf("\n   ");
+      }
+      printf("%d\n};\n\n", png_sRGB_delta[i]);
+   }
+
+   return 0;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/png-fix-itxt.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/png-fix-itxt.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/png-fix-itxt.c	(revision 107811)
@@ -0,0 +1,162 @@
+/* png-fix-itxt
+ *
+ * Copyright 2015 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Usage:
+ *
+ *     png-fix-itxt < bad.png > good.png
+ *
+ * Fixes a PNG file written with libpng-1.6.0 or 1.6.1 that has one or more
+ * uncompressed iTXt chunks.  Assumes that the actual length is greater
+ * than or equal to the value in the length byte, and that the CRC is
+ * correct for the actual length.  This program hunts for the CRC and
+ * adjusts the length byte accordingly.  It is not an error to process a
+ * PNG file that has no iTXt chunks or one that has valid iTXt chunks;
+ * such files will simply be copied.
+ *
+ * Requires zlib (for crc32 and Z_NULL); build with
+ *
+ *     gcc -O -o png-fix-itxt png-fix-itxt.c -lz
+ *
+ * If you need to handle iTXt chunks larger than 500000 kbytes you must
+ * rebuild png-fix-itxt with a larger values of MAX_LENGTH (or a smaller value
+ * if you know you will never encounter such huge iTXt chunks).
+ */
+
+#include <stdio.h>
+#include <zlib.h>
+
+#define MAX_LENGTH 500000
+
+/* Read one character (inchar), also return octet (c), break if EOF */
+#define GETBREAK inchar=getchar(); \
+                 c=(inchar & 0xffU);\
+                 if (inchar != c) break
+int
+main(void)
+{
+   unsigned int i;
+   unsigned char buf[MAX_LENGTH];
+   unsigned long crc;
+   unsigned char c;
+   int inchar;
+
+/* Skip 8-byte signature */
+   for (i=8; i; i--)
+   {
+      GETBREAK;
+      putchar(c);
+   }
+
+if (inchar == c) /* !EOF */
+for (;;)
+ {
+   /* Read the length */
+   unsigned long length; /* must be 32 bits! */
+   GETBREAK; buf[0] = c; length  = c; length <<= 8;
+   GETBREAK; buf[1] = c; length += c; length <<= 8;
+   GETBREAK; buf[2] = c; length += c; length <<= 8;
+   GETBREAK; buf[3] = c; length += c;
+
+   /* Read the chunkname */
+   GETBREAK; buf[4] = c;
+   GETBREAK; buf[5] = c;
+   GETBREAK; buf[6] = c;
+   GETBREAK; buf[7] = c;
+
+
+   /* The iTXt chunk type expressed as integers is (105, 84, 88, 116) */
+   if (buf[4] == 105 && buf[5] == 84 && buf[6] == 88 && buf[7] == 116)
+   {
+      if (length >= MAX_LENGTH-12)
+         break;  /* To do: handle this more gracefully */
+
+      /* Initialize the CRC */
+      crc = crc32(0, Z_NULL, 0);
+
+      /* Copy the data bytes */
+      for (i=8; i < length + 12; i++)
+      {
+         GETBREAK; buf[i] = c;
+      }
+
+      if (inchar != c) /* EOF */
+         break;
+
+      /* Calculate the CRC */
+      crc = crc32(crc, buf+4, (uInt)length+4);
+
+      for (;;)
+      {
+        /* Check the CRC */
+        if (((crc >> 24) & 0xffU) == buf[length+8] &&
+            ((crc >> 16) & 0xffU) == buf[length+9] &&
+            ((crc >>  8) & 0xffU) == buf[length+10] &&
+            ((crc      ) & 0xffU) == buf[length+11])
+           break;
+
+        length++;
+
+        if (length >= MAX_LENGTH-12)
+           break;
+
+        GETBREAK;
+        buf[length+11] = c;
+
+        /* Update the CRC */
+        crc = crc32(crc, buf+7+length, 1);
+      }
+
+      if (inchar != c) /* EOF */
+         break;
+
+      /* Update length bytes */
+      buf[0] = (unsigned char)((length >> 24) & 0xffU);
+      buf[1] = (unsigned char)((length >> 16) & 0xffU);
+      buf[2] = (unsigned char)((length >>  8) & 0xffU);
+      buf[3] = (unsigned char)((length      ) & 0xffU);
+
+      /* Write the fixed iTXt chunk (length, name, data, crc) */
+      for (i=0; i<length+12; i++)
+         putchar(buf[i]);
+   }
+
+   else
+   {
+      if (inchar != c) /* EOF */
+         break;
+
+      /* Copy bytes that were already read (length and chunk name) */
+      for (i=0; i<8; i++)
+         putchar(buf[i]);
+
+      /* Copy data bytes and CRC */
+      for (i=8; i< length+12; i++)
+      {
+         GETBREAK;
+         putchar(c);
+      }
+
+      if (inchar != c) /* EOF */
+      {
+         break;
+      }
+
+   /* The IEND chunk type expressed as integers is (73, 69, 78, 68) */
+      if (buf[4] == 73 && buf[5] == 69 && buf[6] == 78 && buf[7] == 68)
+         break;
+   }
+
+   if (inchar != c) /* EOF */
+      break;
+
+   if (buf[4] == 73 && buf[5] == 69 && buf[6] == 78 && buf[7] == 68)
+     break;
+ }
+
+ return 0;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/pngcp.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/pngcp.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/pngcp.c	(revision 107811)
@@ -0,0 +1,2486 @@
+/* pngcp.c
+ *
+ * Copyright (c) 2016,2022,2024 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This is an example of copying a PNG without changes using the png_read_png
+ * and png_write_png interfaces.  A considerable number of options are provided
+ * to manipulate the compression of the PNG data and other compressed chunks.
+ *
+ * For a more extensive example that uses the transforms see
+ * contrib/libtests/pngimage.c in the libpng distribution.
+ *
+ * This code is not intended for installation in a release system; the command
+ * line options are not documented and most of the behavior is intended for
+ * testing libpng performance, both speed and compression.
+ */
+
+#include "pnglibconf.h" /* To find how libpng was configured. */
+
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+   /* WARNING:
+    *
+    * This test is here to allow POSIX.1b extensions to be used if enabled in
+    * the compile; specifically the code requires_POSIX_C_SOURCE support of
+    * 199309L or later to enable clock_gettime use.
+    *
+    * IF this causes problems THEN compile with a strict ANSI C compiler and let
+    * this code turn on the POSIX features that it minimally requires.
+    *
+    * IF this does not work there is probably a bug in your ANSI C compiler or
+    * your POSIX implementation.
+    */
+#  define _POSIX_C_SOURCE 199309L
+#else /* No timing support required */
+#  define _POSIX_SOURCE 1
+#endif
+
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+#endif
+
+#include <stdio.h>
+
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+   /* READ_PNG and WRITE_PNG were not defined, so: */
+#  ifdef PNG_INFO_IMAGE_SUPPORTED
+#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#        define PNG_READ_PNG_SUPPORTED
+#     endif /* SEQUENTIAL_READ */
+#     ifdef PNG_WRITE_SUPPORTED
+#        define PNG_WRITE_PNG_SUPPORTED
+#     endif /* WRITE */
+#  endif /* INFO_IMAGE */
+#endif /* pre 1.7.0 */
+
+#if (defined(PNG_READ_PNG_SUPPORTED)) && (defined(PNG_WRITE_PNG_SUPPORTED))
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+#include <assert.h>
+
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include <zlib.h>
+
+#ifndef PNG_SETJMP_SUPPORTED
+#  include <setjmp.h> /* because png.h did *not* include this */
+#endif
+
+#ifdef __cplusplus
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+/* 'CLOCK_PROCESS_CPUTIME_ID' is one of the clock timers for clock_gettime.  It
+ * need not be supported even when clock_gettime is available.  It returns the
+ * 'CPU' time the process has consumed.  'CPU' time is assumed to include time
+ * when the CPU is actually blocked by a pending cache fill but not time
+ * waiting for page faults.  The attempt is to get a measure of the actual time
+ * the implementation takes to read a PNG ignoring the potentially very large IO
+ * overhead.
+ */
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+#  include <time.h>   /* clock_gettime and associated definitions */
+#  ifndef CLOCK_PROCESS_CPUTIME_ID
+      /* Prevent inclusion of the spurious code: */
+#     undef PNG_PNGCP_TIMING_SUPPORTED
+#  endif
+#endif /* PNGCP_TIMING */
+
+/* So if the timing feature has been activated: */
+
+/* This structure is used to control the test of a single file. */
+typedef enum
+{
+   VERBOSE,        /* switches on all messages */
+   INFORMATION,
+   WARNINGS,       /* switches on warnings */
+   LIBPNG_WARNING,
+   APP_WARNING,
+   ERRORS,         /* just errors */
+   APP_FAIL,       /* continuable error - no need to longjmp */
+   LIBPNG_ERROR,   /* this and higher cause a longjmp */
+   LIBPNG_BUG,     /* erroneous behavior in libpng */
+   APP_ERROR,      /* such as out-of-memory in a callback */
+   QUIET,          /* no normal messages */
+   USER_ERROR,     /* such as file-not-found */
+   INTERNAL_ERROR
+} error_level;
+#define LEVEL_MASK      0xf   /* where the level is in 'options' */
+
+#define STRICT          0x010 /* Fail on warnings as well as errors */
+#define LOG             0x020 /* Log pass/fail to stdout */
+#define CONTINUE        0x040 /* Continue on APP_FAIL errors */
+#define SIZES           0x080 /* Report input and output sizes */
+#define SEARCH          0x100 /* Search IDAT compression options */
+#define NOWRITE         0x200 /* Do not write an output file */
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#  define IGNORE_INDEX  0x400 /* Ignore out of range palette indices (BAD!) */
+#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+#     define FIX_INDEX  0x800 /* 'Fix' out of range palette indices (OK) */
+#  endif /* GET_PALETTE_MAX */
+#endif /* CHECK_FOR_INVALID_INDEX */
+#define OPTION     0x80000000 /* Used for handling options */
+#define LIST       0x80000001 /* Used for handling options */
+
+/* Result masks apply to the result bits in the 'results' field below; these
+ * bits are simple 1U<<error_level.  A pass requires either nothing worse than
+ * warnings (--relaxes) or nothing worse than information (--strict)
+ */
+#define RESULT_STRICT(r)   (((r) & ~((1U<<WARNINGS)-1)) == 0)
+#define RESULT_RELAXED(r)  (((r) & ~((1U<<ERRORS)-1)) == 0)
+
+/* OPTION DEFINITIONS */
+static const char range_lo[] = "low";
+static const char range_hi[] = "high";
+static const char all[] = "all";
+#define RANGE(lo,hi) { range_lo, lo }, { range_hi, hi }
+typedef struct value_list
+{
+   const char *name;  /* the command line name of the value */
+   int         value; /* the actual value to use */
+}  value_list;
+
+static const value_list
+#ifdef PNG_SW_COMPRESS_png_level
+vl_compression[] =
+{
+   /* Overall compression control.  The order controls the search order for
+    * 'all'.  Since the search is for the smallest the order used is low memory
+    * then high speed.
+    */
+   { "low-memory",      PNG_COMPRESSION_LOW_MEMORY },
+   { "high-speed",      PNG_COMPRESSION_HIGH_SPEED },
+   { "high-read-speed", PNG_COMPRESSION_HIGH_READ_SPEED },
+   { "low",             PNG_COMPRESSION_LOW },
+   { "medium",          PNG_COMPRESSION_MEDIUM },
+   { "old",             PNG_COMPRESSION_COMPAT },
+   { "high",            PNG_COMPRESSION_HIGH },
+   { all, 0 }
+},
+#endif /* SW_COMPRESS_png_level */
+
+#if defined(PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED) ||\
+    defined(PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED)
+vl_strategy[] =
+{
+   /* This controls the order of search. */
+   { "huffman", Z_HUFFMAN_ONLY },
+   { "RLE", Z_RLE },
+   { "fixed", Z_FIXED }, /* the remainder do window searches */
+   { "filtered", Z_FILTERED },
+   { "default", Z_DEFAULT_STRATEGY },
+   { all, 0 }
+},
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+vl_windowBits_text[] =
+{
+   { "default", MAX_WBITS/*from zlib*/ },
+   { "minimum", 8 },
+   RANGE(8, MAX_WBITS/*from zlib*/),
+   { all, 0 }
+},
+#endif /* text compression */
+vl_level[] =
+{
+   { "default", Z_DEFAULT_COMPRESSION /* this is -1 */ },
+   { "none", Z_NO_COMPRESSION },
+   { "speed", Z_BEST_SPEED },
+   { "best", Z_BEST_COMPRESSION },
+   { "0", Z_NO_COMPRESSION },
+   RANGE(1, 9), /* this deliberately excludes '0' */
+   { all, 0 }
+},
+vl_memLevel[] =
+{
+   { "max", MAX_MEM_LEVEL }, /* zlib maximum */
+   { "1", 1 }, /* zlib minimum */
+   { "default", 8 }, /* zlib default */
+   { "2", 2 },
+   { "3", 3 },
+   { "4", 4 },
+   { "5", 5 }, /* for explicit testing */
+   RANGE(6, MAX_MEM_LEVEL/*zlib*/), /* exclude 5 and below: zlib bugs */
+   { all, 0 }
+},
+#endif /* WRITE_CUSTOMIZE_*COMPRESSION */
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+vl_filter[] =
+{
+   { all,      PNG_ALL_FILTERS   },
+   { "off",    PNG_NO_FILTERS    },
+   { "none",   PNG_FILTER_NONE   },
+   { "sub",    PNG_FILTER_SUB    },
+   { "up",     PNG_FILTER_UP     },
+   { "avg",    PNG_FILTER_AVG    },
+   { "paeth",  PNG_FILTER_PAETH  }
+},
+#endif /* WRITE_FILTER */
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+#  define PNGCP_TIME_READ  1
+#  define PNGCP_TIME_WRITE 2
+vl_time[] =
+{
+   { "both",  PNGCP_TIME_READ+PNGCP_TIME_WRITE },
+   { "off",   0 },
+   { "read",  PNGCP_TIME_READ },
+   { "write", PNGCP_TIME_WRITE }
+},
+#endif /* PNGCP_TIMING */
+vl_IDAT_size[] = /* for png_set_IDAT_size */
+{
+   { "default", 0x7FFFFFFF },
+   { "minimal", 1 },
+   RANGE(1, 0x7FFFFFFF)
+},
+#ifndef PNG_SW_IDAT_size
+   /* Pre 1.7 API: */
+#  define png_set_IDAT_size(p,v) png_set_compression_buffer_size(p, v)
+#endif /* !SW_IDAT_size */
+#define SL 8 /* stack limit in display, below */
+vl_log_depth[] = { { "on", 1 }, { "off", 0 }, RANGE(0, SL) },
+vl_on_off[] = { { "on", 1 }, { "off", 0 } };
+
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+static value_list
+vl_windowBits_IDAT[] =
+{
+   { "default", MAX_WBITS },
+   { "small", 9 },
+   RANGE(8, MAX_WBITS), /* modified by set_windowBits_hi */
+   { all, 0 }
+};
+#endif /* IDAT compression */
+
+typedef struct option
+{
+   const char       *name;         /* name of the option */
+   png_uint_32       opt;          /* an option, or OPTION or LIST */
+   png_byte          search;       /* Search on --search */
+   png_byte          value_count;  /* length of the list of values: */
+   const value_list *values;       /* values for OPTION or LIST */
+}  option;
+
+static const option options[] =
+{
+   /* struct display options, these are set when the command line is read */
+#  define S(n,v) { #n, v, 0, 2, vl_on_off },
+   S(verbose,  VERBOSE)
+   S(warnings, WARNINGS)
+   S(errors,   ERRORS)
+   S(quiet,    QUIET)
+   S(strict,   STRICT)
+   S(log,      LOG)
+   S(continue, CONTINUE)
+   S(sizes,    SIZES)
+   S(search,   SEARCH)
+   S(nowrite,  NOWRITE)
+#  ifdef IGNORE_INDEX
+      S(ignore-palette-index, IGNORE_INDEX)
+#  endif /* IGNORE_INDEX */
+#  ifdef FIX_INDEX
+      S(fix-palette-index, FIX_INDEX)
+#  endif /* FIX_INDEX */
+#  undef S
+
+   /* OPTION settings, these and LIST settings are read on demand */
+#  define VLNAME(name) vl_ ## name
+#  define VLSIZE(name) voidcast(png_byte,\
+                           (sizeof VLNAME(name))/(sizeof VLNAME(name)[0]))
+#  define VL(oname, name, type, search)\
+   { oname, type, search, VLSIZE(name), VLNAME(name) },
+#  define VLO(oname, name, search) VL(oname, name, OPTION, search)
+
+#  ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+#     define VLCIDAT(name) VLO(#name, name, 1/*search*/)
+#     ifdef PNG_SW_COMPRESS_level
+#        define VLCiCCP(name) VLO("ICC-profile-" #name, name, 0/*search*/)
+#     else
+#        define VLCiCCP(name)
+#     endif
+#  else
+#     define VLCIDAT(name)
+#     define VLCiCCP(name)
+#  endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+#  ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#     define VLCzTXt(name) VLO("text-" #name, name, 0/*search*/)
+#  else
+#     define VLCzTXt(name)
+#  endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+
+#  define VLC(name) VLCIDAT(name) VLCiCCP(name) VLCzTXt(name)
+
+#  ifdef PNG_SW_COMPRESS_png_level
+      /* The libpng compression level isn't searched because it just sets the
+       * other things that are searched!
+       */
+      VLO("compression", compression, 0)
+      VLO("text-compression", compression, 0)
+      VLO("ICC-profile-compression", compression, 0)
+#  endif /* SW_COMPRESS_png_level */
+   VLC(strategy)
+   VLO("windowBits", windowBits_IDAT, 1)
+#  ifdef PNG_SW_COMPRESS_windowBits
+      VLO("ICC-profile-windowBits", windowBits_text/*sic*/, 0)
+#  endif
+   VLO("text-windowBits", windowBits_text, 0)
+   VLC(level)
+   VLC(memLevel)
+   VLO("IDAT-size", IDAT_size, 0)
+   VLO("log-depth", log_depth, 0)
+
+#  undef VLO
+
+   /* LIST settings */
+#  define VLL(name, search) VL(#name, name, LIST, search)
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   VLL(filter, 0)
+#endif /* WRITE_FILTER */
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+   VLL(time, 0)
+#endif /* PNGCP_TIMING */
+#  undef VLL
+#  undef VL
+};
+
+#ifdef __cplusplus
+   static const size_t option_count((sizeof options)/(sizeof options[0]));
+#else /* !__cplusplus */
+#  define option_count ((sizeof options)/(sizeof options[0]))
+#endif /* !__cplusplus */
+
+static const char *
+cts(int ct)
+{
+   switch (ct)
+   {
+      case PNG_COLOR_TYPE_PALETTE:     return "P";
+      case PNG_COLOR_TYPE_GRAY:        return "G";
+      case PNG_COLOR_TYPE_GRAY_ALPHA:  return "GA";
+      case PNG_COLOR_TYPE_RGB:         return "RGB";
+      case PNG_COLOR_TYPE_RGB_ALPHA:   return "RGBA";
+      default:                         return "INVALID";
+   }
+}
+
+struct display
+{
+   jmp_buf          error_return;      /* Where to go to on error */
+   unsigned int     errset;            /* error_return is set */
+   int              errlevel;          /* error level from longjmp */
+
+   const char      *operation;         /* What is happening */
+   const char      *filename;          /* The name of the original file */
+   const char      *output_file;       /* The name of the output file */
+
+   /* Used on both read and write: */
+   FILE            *fp;
+
+   /* Used on a read, both the original read and when validating a written
+    * image.
+    */
+   png_alloc_size_t read_size;
+   png_structp      read_pp;
+   png_infop        ip;
+#  if PNG_LIBPNG_VER < 10700 && defined PNG_TEXT_SUPPORTED
+      png_textp     text_ptr; /* stash of text chunks */
+      int           num_text;
+      int           text_stashed;
+#  endif /* pre 1.7 */
+
+#  ifdef PNG_PNGCP_TIMING_SUPPORTED
+      struct timespec   read_time;
+      struct timespec   read_time_total;
+      struct timespec   write_time;
+      struct timespec   write_time_total;
+#  endif /* PNGCP_TIMING */
+
+   /* Used to write a new image (the original info_ptr is used) */
+#  define MAX_SIZE ((png_alloc_size_t)(-1))
+   png_alloc_size_t write_size;
+   png_alloc_size_t best_size;
+   png_structp      write_pp;
+
+   /* Base file information */
+   png_alloc_size_t size;
+   png_uint_32      w;
+   png_uint_32      h;
+   int              bpp;
+   png_byte         ct;
+   int              no_warnings;       /* Do not output libpng warnings */
+   int              min_windowBits;    /* The windowBits range is 8..8 */
+
+   /* Options handling */
+   png_uint_32      results;             /* A mask of errors seen */
+   png_uint_32      options;             /* See display_log below */
+   png_byte         entry[option_count]; /* The selected entry+1 of an option
+                                          * that appears on the command line, or
+                                          * 0 if it was not given. */
+   int              value[option_count]; /* Corresponding value */
+
+   /* Compression exhaustive testing */
+   /* Temporary variables used only while testing a single collection of
+    * settings:
+    */
+   unsigned int     csp;               /* next stack entry to use */
+   unsigned int     nsp;               /* highest active entry+1 found so far */
+
+   /* Values used while iterating through all the combinations of settings for a
+    * single file:
+    */
+   unsigned int     tsp;               /* nsp from the last run; this is the
+                                        * index+1 of the highest active entry on
+                                        * this run; this entry will be advanced.
+                                        */
+   int              opt_string_start;  /* Position in buffer for the first
+                                        * searched option; non-zero if earlier
+                                        * options were set on the command line.
+                                        */
+   struct stack
+   {
+      png_alloc_size_t best_size;      /* Best so far for this option */
+      png_alloc_size_t lo_size;
+      png_alloc_size_t hi_size;
+      int              lo, hi;         /* For binary chop of a range */
+      int              best_val;       /* Best value found so far */
+      int              opt_string_end; /* End of the option string in 'curr' */
+      png_byte         opt;            /* The option being tested */
+      png_byte         entry;          /* The next value entry to be tested */
+      png_byte         end;            /* This is the last entry */
+   }                stack[SL];         /* Stack of entries being tested */
+   char             curr[32*SL];       /* current options being tested */
+   char             best[32*SL];       /* best options */
+
+   char             namebuf[FILENAME_MAX]; /* output file name */
+};
+
+static void
+display_init(struct display *dp)
+   /* Call this only once right at the start to initialize the control
+    * structure, the (struct buffer) lists are maintained across calls - the
+    * memory is not freed.
+    */
+{
+   memset(dp, 0, sizeof *dp);
+   dp->operation = "internal error";
+   dp->filename = "command line";
+   dp->output_file = "no output file";
+   dp->options = WARNINGS; /* default to !verbose, !quiet */
+   dp->fp = NULL;
+   dp->read_pp = NULL;
+   dp->ip = NULL;
+   dp->write_pp = NULL;
+   dp->min_windowBits = -1; /* this is an OPTIND, so -1 won't match anything */
+#  if PNG_LIBPNG_VER < 10700 && defined PNG_TEXT_SUPPORTED
+      dp->text_ptr = NULL;
+      dp->num_text = 0;
+      dp->text_stashed = 0;
+#  endif /* pre 1.7 */
+}
+
+static void
+display_clean_read(struct display *dp, int freeinfo)
+{
+   if (dp->read_pp != NULL)
+      png_destroy_read_struct(&dp->read_pp, freeinfo ? &dp->ip : NULL, NULL);
+
+   if (dp->fp != NULL)
+   {
+      FILE *fp = dp->fp;
+      dp->fp = NULL;
+      (void)fclose(fp);
+   }
+}
+
+static void
+display_clean_write(struct display *dp, int freeinfo)
+{
+   if (dp->fp != NULL)
+   {
+      FILE *fp = dp->fp;
+      dp->fp = NULL;
+      (void)fclose(fp);
+   }
+
+   if (dp->write_pp != NULL)
+      png_destroy_write_struct(&dp->write_pp, freeinfo ? &dp->ip : NULL);
+}
+
+static void
+display_clean(struct display *dp)
+{
+   display_clean_read(dp, 1/*freeinfo*/);
+   display_clean_write(dp, 1/*freeinfo*/);
+   dp->output_file = NULL;
+
+#  if PNG_LIBPNG_VER < 10700 && defined PNG_TEXT_SUPPORTED
+      /* This is actually created and used by the write code, but only
+       * once; it has to be retained for subsequent writes of the same file.
+       */
+      if (dp->text_stashed)
+      {
+         dp->text_stashed = 0;
+         dp->num_text = 0;
+         free(dp->text_ptr);
+         dp->text_ptr = NULL;
+      }
+#  endif /* pre 1.7 */
+
+   /* leave the filename for error detection */
+   dp->results = 0; /* reset for next time */
+}
+
+static void
+display_destroy(struct display *dp)
+{
+   /* Release any memory held in the display. */
+   display_clean(dp);
+}
+
+static struct display *
+get_dp(png_structp pp)
+   /* The display pointer is always stored in the png_struct error pointer */
+{
+   struct display *dp = (struct display*)png_get_error_ptr(pp);
+
+   if (dp == NULL)
+   {
+      fprintf(stderr, "pngcp: internal error (no display)\n");
+      exit(99); /* prevents a crash */
+   }
+
+   return dp;
+}
+
+/* error handling */
+#ifdef __GNUC__
+#  define VGATTR __attribute__((__format__ (__printf__,3,4)))
+   /* Required to quiet GNUC warnings when the compiler sees a stdarg function
+    * that calls one of the stdio v APIs.
+    */
+#else
+#  define VGATTR
+#endif
+static void VGATTR
+display_log(struct display *dp, error_level level, const char *fmt, ...)
+   /* 'level' is as above, fmt is a stdio style format string.  This routine
+    * does not return if level is above LIBPNG_WARNING
+    */
+{
+   dp->results |= 1U << level;
+
+   if (level > (error_level)(dp->options & LEVEL_MASK))
+   {
+      const char *lp;
+      va_list ap;
+
+      switch (level)
+      {
+         case INFORMATION:    lp = "information"; break;
+         case LIBPNG_WARNING: lp = "warning(libpng)"; break;
+         case APP_WARNING:    lp = "warning(pngcp)"; break;
+         case APP_FAIL:       lp = "error(continuable)"; break;
+         case LIBPNG_ERROR:   lp = "error(libpng)"; break;
+         case LIBPNG_BUG:     lp = "bug(libpng)"; break;
+         case APP_ERROR:      lp = "error(pngcp)"; break;
+         case USER_ERROR:     lp = "error(user)"; break;
+
+         case INTERNAL_ERROR: /* anything unexpected is an internal error: */
+         case VERBOSE: case WARNINGS: case ERRORS: case QUIET:
+         default:             lp = "bug(pngcp)"; break;
+      }
+
+      fprintf(stderr, "%s: %s: %s",
+         dp->filename != NULL ? dp->filename : "<stdin>", lp, dp->operation);
+
+      fprintf(stderr, ": ");
+
+      va_start(ap, fmt);
+      vfprintf(stderr, fmt, ap);
+      va_end(ap);
+
+      fputc('\n', stderr);
+   }
+   /* else do not output any message */
+
+   /* Errors cause this routine to exit to the fail code */
+   if (level > APP_FAIL || (level > ERRORS && !(dp->options & CONTINUE)))
+   {
+      if (dp->errset)
+      {
+         dp->errlevel = level;
+         longjmp(dp->error_return, level);
+      }
+
+      else
+         exit(99);
+   }
+}
+
+#if PNG_LIBPNG_VER < 10700 && defined PNG_TEXT_SUPPORTED
+static void
+text_stash(struct display *dp)
+{
+   /* libpng 1.6 and earlier fixed a bug whereby text chunks were written
+    * multiple times by png_write_png; the issue was that png_write_png passed
+    * the same png_info to both png_write_info and png_write_end.  Rather than
+    * fixing it by recording the information in the png_struct, or by recording
+    * where to write the chunks, the fix made was to change the 'compression'
+    * field of the chunk to invalid values, rendering the png_info somewhat
+    * useless.
+    *
+    * The only fix for this given that we use the png_info more than once is to
+    * make a copy of the text chunks and png_set_text it each time.  This adds a
+    * text chunks, so they get replicated, but only the new set gets written
+    * each time.  This uses memory like crazy but there is no way to delete the
+    * useless chunks from the png_info.
+    *
+    * To make this slightly more efficient only the top level structure is
+    * copied; since the old strings are actually preserved (in 1.6 and earlier)
+    * this happens to work.
+    */
+   png_textp chunks = NULL;
+
+   dp->num_text = png_get_text(dp->write_pp, dp->ip, &chunks, NULL);
+
+   if (dp->num_text > 0)
+   {
+      dp->text_ptr = voidcast(png_textp, malloc(dp->num_text * sizeof *chunks));
+
+      if (dp->text_ptr == NULL)
+         display_log(dp, APP_ERROR, "text chunks: stash malloc failed");
+
+      else
+         memcpy(dp->text_ptr, chunks, dp->num_text * sizeof *chunks);
+   }
+
+   dp->text_stashed = 1; /* regardless of whether there are chunks or not */
+}
+
+#define text_stash(dp) if (!dp->text_stashed) text_stash(dp)
+
+static void
+text_restore(struct display *dp)
+{
+   /* libpng makes a copy, so this is fine: */
+   if (dp->text_ptr != NULL)
+      png_set_text(dp->write_pp, dp->ip, dp->text_ptr, dp->num_text);
+}
+
+#define text_restore(dp) if (dp->text_stashed) text_restore(dp)
+
+#else
+#define text_stash(dp) ((void)0)
+#define text_restore(dp) ((void)0)
+#endif /* pre 1.7 */
+
+/* OPTIONS:
+ *
+ * The command handles options of the forms:
+ *
+ *    --option
+ *       Turn an option on (Option)
+ *    --no-option
+ *       Turn an option off (Option)
+ *    --option=value
+ *       Set an option to a value (Value)
+ *    --option=val1,val2,val3
+ *       Set an option to a bitmask constructed from the values (List)
+ */
+static png_byte
+option_index(struct display *dp, const char *opt, size_t len)
+   /* Return the index (in options[]) of the given option, outputs an error if
+    * it does not exist.  Takes the name of the option and a length (number of
+    * characters in the name).
+    */
+{
+   png_byte j;
+
+   for (j=0; j<option_count; ++j)
+      if (strncmp(options[j].name, opt, len) == 0 && options[j].name[len] == 0)
+         return j;
+
+   /* If the setjmp buffer is set the code is asking for an option index; this
+    * is bad.  Otherwise this is the command line option parsing.
+    */
+   display_log(dp, dp->errset ? INTERNAL_ERROR : USER_ERROR,
+         "%.*s: unknown option", (int)/*SAFE*/len, opt);
+   abort(); /* NOT REACHED */
+}
+
+/* This works for an option name (no quotes): */
+#define OPTIND(dp, name) option_index(dp, #name, (sizeof #name)-1)
+
+static int
+get_option(struct display *dp, const char *opt, int *value)
+{
+   png_byte i = option_index(dp, opt, strlen(opt));
+
+   if (dp->entry[i]) /* option was set on command line */
+   {
+      *value = dp->value[i];
+      return 1;
+   }
+
+   else
+      return 0;
+}
+
+static int
+set_opt_string_(struct display *dp, unsigned int sp, png_byte opt,
+      const char *entry_name)
+   /* Add the appropriate option string to dp->curr. */
+{
+   int offset, add;
+
+   if (sp > 0)
+      offset = dp->stack[sp-1].opt_string_end;
+
+   else
+      offset = dp->opt_string_start;
+
+   if (entry_name == range_lo)
+      add = sprintf(dp->curr+offset, " --%s=%d", options[opt].name,
+            dp->value[opt]);
+
+   else
+      add = sprintf(dp->curr+offset, " --%s=%s", options[opt].name, entry_name);
+
+   if (add < 0)
+      display_log(dp, INTERNAL_ERROR, "sprintf failed");
+
+   assert(offset+add < (int)/*SAFE*/sizeof dp->curr);
+   return offset+add;
+}
+
+static void
+set_opt_string(struct display *dp, unsigned int sp)
+   /* Add the appropriate option string to dp->curr. */
+{
+   dp->stack[sp].opt_string_end = set_opt_string_(dp, sp, dp->stack[sp].opt,
+      options[dp->stack[sp].opt].values[dp->stack[sp].entry].name);
+}
+
+static void
+record_opt(struct display *dp, png_byte opt, const char *entry_name)
+   /* Record this option in dp->curr; called for an option not being searched,
+    * the caller passes in the name of the value, or range_lo to use the
+    * numerical value.
+    */
+{
+   unsigned int sp = dp->csp; /* stack entry of next searched option */
+
+   if (sp >= dp->tsp)
+   {
+      /* At top of stack; add the opt string for this entry to the previous
+       * searched entry or the start of the dp->curr buffer if there is nothing
+       * on the stack yet (sp == 0).
+       */
+      int offset = set_opt_string_(dp, sp, opt, entry_name);
+
+      if (sp > 0)
+         dp->stack[sp-1].opt_string_end = offset;
+
+      else
+         dp->opt_string_start = offset;
+   }
+
+   /* else do nothing: option already recorded */
+}
+
+static int
+opt_list_end(struct display *dp, png_byte opt, png_byte entry)
+{
+   if (options[opt].values[entry].name == range_lo)
+      return entry+1U >= options[opt].value_count /* missing range_hi */ ||
+         options[opt].values[entry+1U].name != range_hi /* likewise */ ||
+         options[opt].values[entry+1U].value <= dp->value[opt] /* range end */;
+
+   else
+      return entry+1U >= options[opt].value_count /* missing 'all' */ ||
+         options[opt].values[entry+1U].name == all /* last entry */;
+}
+
+static void
+push_opt(struct display *dp, unsigned int sp, png_byte opt, int search)
+   /* Push a new option onto the stack, initializing the new stack entry
+    * appropriately; this does all the work of next_opt (setting end/nsp) for
+    * the first entry in the list.
+    */
+{
+   png_byte entry;
+   const char *entry_name;
+
+   assert(sp == dp->tsp && sp < SL);
+
+   /* The starting entry is entry 0 unless there is a range in which case it is
+    * the entry corresponding to range_lo:
+    */
+   entry = options[opt].value_count;
+   assert(entry > 0U);
+
+   do
+   {
+      entry_name = options[opt].values[--entry].name;
+      if (entry_name == range_lo)
+         break;
+   }
+   while (entry > 0U);
+
+   dp->tsp = sp+1U;
+   dp->stack[sp].best_size =
+      dp->stack[sp].lo_size =
+      dp->stack[sp].hi_size = MAX_SIZE;
+
+   if (search && entry_name == range_lo) /* search this range */
+   {
+      dp->stack[sp].lo = options[opt].values[entry].value;
+      /* check for a mal-formed RANGE above: */
+      assert(entry+1 < options[opt].value_count &&
+             options[opt].values[entry+1].name == range_hi);
+      dp->stack[sp].hi = options[opt].values[entry+1].value;
+   }
+
+   else
+   {
+      /* next_opt will just iterate over the range. */
+      dp->stack[sp].lo = INT_MAX;
+      dp->stack[sp].hi = INT_MIN; /* Prevent range chop */
+   }
+
+   dp->stack[sp].opt = opt;
+   dp->stack[sp].entry = entry;
+   dp->stack[sp].best_val = dp->value[opt] = options[opt].values[entry].value;
+
+   set_opt_string(dp, sp);
+
+   /* This works for the search case too; if the range has only one entry 'end'
+    * will be marked here.
+    */
+   if (opt_list_end(dp, opt, entry))
+   {
+      dp->stack[sp].end = 1;
+      /* Skip the warning if pngcp did this itself.  See the code in
+       * set_windowBits_hi.
+       */
+      if (opt != dp->min_windowBits)
+         display_log(dp, APP_WARNING, "%s: only testing one value",
+               options[opt].name);
+   }
+
+   else
+   {
+      dp->stack[sp].end = 0;
+      dp->nsp = dp->tsp;
+   }
+
+   /* Do a lazy cache of the text chunks for libpng 1.6 and earlier; this is
+    * because they can only be written once(!) so if we are going to re-use the
+    * png_info we need a copy.
+    */
+   text_stash(dp);
+}
+
+static void
+next_opt(struct display *dp, unsigned int sp)
+   /* Return the next value for this option.  When called 'sp' is expected to be
+    * the topmost stack entry - only the topmost entry changes each time round -
+    * and there must be a valid entry to return.  next_opt will set dp->nsp to
+    * sp+1 if more entries are available, otherwise it will not change it and
+    * set dp->stack[s].end to true.
+    */
+{
+   int search = 0;
+   png_byte entry, opt;
+   const char *entry_name;
+
+   /* dp->stack[sp] must be the top stack entry and it must be active: */
+   assert(sp+1U == dp->tsp && !dp->stack[sp].end);
+
+   opt = dp->stack[sp].opt;
+   entry = dp->stack[sp].entry;
+   assert(entry+1U < options[opt].value_count);
+   entry_name = options[opt].values[entry].name;
+   assert(entry_name != NULL);
+
+   /* For ranges increment the value but don't change the entry, for all other
+    * cases move to the next entry and load its value:
+    */
+   if (entry_name == range_lo) /* a range */
+   {
+      /* A range can be iterated over or searched.  The default iteration option
+       * is indicated by hi < lo on the stack, otherwise the range being search
+       * is [lo..hi] (inclusive).
+       */
+      if (dp->stack[sp].lo > dp->stack[sp].hi)
+         dp->value[opt]++;
+
+      else
+      {
+         /* This is the best size found for this option value: */
+         png_alloc_size_t best_size = dp->stack[sp].best_size;
+         int lo = dp->stack[sp].lo;
+         int hi = dp->stack[sp].hi;
+         int val = dp->value[opt];
+
+         search = 1; /* end is determined here */
+         assert(best_size < MAX_SIZE);
+
+         if (val == lo)
+         {
+            /* Finding the best for the low end of the range: */
+            dp->stack[sp].lo_size = best_size;
+            assert(hi > val);
+
+            if (hi == val+1) /* only 2 entries */
+               dp->stack[sp].end = 1;
+
+            val = hi;
+         }
+
+         else if (val == hi)
+         {
+            dp->stack[sp].hi_size = best_size;
+            assert(val > lo+1); /* else 'end' set above */
+
+            if (val == lo+2) /* only three entries to test */
+               dp->stack[sp].end = 1;
+
+            val = (lo + val)/2;
+         }
+
+         else
+         {
+            png_alloc_size_t lo_size = dp->stack[sp].lo_size;
+            png_alloc_size_t hi_size = dp->stack[sp].hi_size;
+
+            /* lo and hi should have been tested. */
+            assert(lo_size < MAX_SIZE && hi_size < MAX_SIZE);
+
+            /* These cases arise with the 'probe' handling below when there is a
+             * dip or peak in the size curve.
+             */
+            if (val < lo) /* probing a new lo */
+            {
+               /* Swap lo and val: */
+               dp->stack[sp].lo = val;
+               dp->stack[sp].lo_size = best_size;
+               val = lo;
+               best_size = lo_size;
+               lo = dp->stack[sp].lo;
+               lo_size = dp->stack[sp].lo_size;
+            }
+
+            else if (val > hi) /* probing a new hi */
+            {
+               /* Swap hi and val: */
+               dp->stack[sp].hi = val;
+               dp->stack[sp].hi_size = best_size;
+               val = hi;
+               best_size = hi_size;
+               hi = dp->stack[sp].hi;
+               hi_size = dp->stack[sp].hi_size;
+            }
+
+            /* The following should be true or something got messed up above. */
+            assert(lo < val && val < hi);
+
+            /* If there are only four entries (lo, val, hi plus one more) just
+             * test the remaining entry.
+             */
+            if (hi == lo+3)
+            {
+               /* Because of the 'probe' code val can either be lo+1 or hi-1; we
+                * need to test the other.
+                */
+               val = lo + ((val == lo+1) ? 2 : 1);
+               assert(lo < val && val < hi);
+               dp->stack[sp].end = 1;
+            }
+
+            else
+            {
+               /* There are at least 2 entries still untested between lo and hi,
+                * i.e. hi >= lo+4.  'val' is the midpoint +/- 0.5
+                *
+                * Separate out the four easy cases when lo..val..hi are
+                * monotonically decreased or (more weird) increasing:
+                */
+               assert(hi > lo+3);
+
+               if (lo_size <= best_size && best_size <= hi_size)
+               {
+                  /* Select the low range; testing this first favours the low
+                   * range over the high range when everything comes out equal.
+                   * Because of the probing 'val' may be lo+1.  In that case end
+                   * the search and set 'val' to lo+2.
+                   */
+                  if (val == lo+1)
+                  {
+                     ++val;
+                     dp->stack[sp].end = 1;
+                  }
+
+                  else
+                  {
+                     dp->stack[sp].hi = hi = val;
+                     dp->stack[sp].hi_size = best_size;
+                     val = (lo + val) / 2;
+                  }
+               }
+
+               else if (lo_size >= best_size && best_size >= hi_size)
+               {
+                  /* Monotonically decreasing size; this is the expected case.
+                   * Select the high end of the range.  As above, val may be
+                   * hi-1.
+                   */
+                  if (val == hi-1)
+                  {
+                     --val;
+                     dp->stack[sp].end = 1;
+                  }
+
+                  else
+                  {
+                     dp->stack[sp].lo = lo = val;
+                     dp->stack[sp].lo_size = best_size;
+                     val = (val + hi) / 2;
+                  }
+               }
+
+               /* If both those tests failed 'best_size' is either greater than
+                * or less than both lo_size and hi_size.  There is a peak or dip
+                * in the curve of sizes from lo to hi and val is on the peak or
+                * dip.
+                *
+                * Because the ranges being searched as so small (level is 1..9,
+                * windowBits 8..15, memLevel 1..9) there will only be at most
+                * three untested values between lo..val and val..hi, so solve
+                * the problem by probing down from hi or up from lo, whichever
+                * is the higher.
+                *
+                * This is the place where 'val' is set to outside the range
+                * lo..hi, described as 'probing', though maybe 'narrowing' would
+                * be more accurate.
+                */
+               else if (lo_size <= hi_size) /* down from hi */
+               {
+                  dp->stack[sp].hi = val;
+                  dp->stack[sp].hi_size = best_size;
+                  val = --hi;
+               }
+
+               else /* up from low */
+               {
+                  dp->stack[sp].lo = val;
+                  dp->stack[sp].lo_size = best_size;
+                  val = ++lo;
+               }
+
+               /* lo and hi are still the true range limits, check for the end
+                * condition.
+                */
+               assert(hi > lo+1);
+               if (hi <= lo+2)
+                  dp->stack[sp].end = 1;
+            }
+         }
+
+         assert(val != dp->stack[sp].best_val); /* should be a new value */
+         dp->value[opt] = val;
+         dp->stack[sp].best_size = MAX_SIZE;
+      }
+   }
+
+   else
+   {
+      /* Increment 'entry' */
+      dp->value[opt] = options[opt].values[++entry].value;
+      dp->stack[sp].entry = entry;
+   }
+
+   set_opt_string(dp, sp);
+
+   if (!search && opt_list_end(dp, opt, entry)) /* end of list */
+      dp->stack[sp].end = 1;
+
+   else if (!dp->stack[sp].end) /* still active after all these tests */
+      dp->nsp = dp->tsp;
+}
+
+static int
+compare_option(const struct display *dp, unsigned int sp)
+{
+   int opt = dp->stack[sp].opt;
+
+   /* If the best so far is numerically less than the current value the
+    * current set of options is invariably worse.
+    */
+   if (dp->stack[sp].best_val < dp->value[opt])
+      return -1;
+
+   /* Lists of options are searched out of numerical order (currently only
+    * strategy), so only return +1 here when a range is being searched.
+    */
+   else if (dp->stack[sp].best_val > dp->value[opt])
+   {
+      if (dp->stack[sp].lo <= dp->stack[sp].hi /*searching*/)
+         return 1;
+
+      else
+         return -1;
+   }
+
+   else
+      return 0; /* match; current value is the best one */
+}
+
+static int
+advance_opt(struct display *dp, png_byte opt, int search)
+{
+   unsigned int sp = dp->csp++; /* my stack entry */
+
+   assert(sp >= dp->nsp); /* nsp starts off zero */
+
+   /* If the entry was active in the previous run dp->stack[sp] is already
+    * set up and dp->tsp will be greater than sp, otherwise a new entry
+    * needs to be created.
+    *
+    * dp->nsp is handled this way:
+    *
+    * 1) When an option is pushed onto the stack dp->nsp and dp->tsp are
+    *    both set (by push_opt) to the next stack entry *unless* there is
+    *    only one entry in the new list, in which case dp->stack[sp].end
+    *    is set.
+    *
+    * 2) For the top stack entry next_opt is called.  The entry must be
+    *    active (dp->stack[sp].end is not set) and either 'nsp' or 'end'
+    *    will be updated as appropriate.
+    *
+    * 3) For lower stack entries nsp is set unless the stack entry is
+    *    already at the end.  This means that when all the higher entries
+    *    are popped this entry will be too.
+    */
+   if (sp >= dp->tsp)
+   {
+      push_opt(dp, sp, opt, search); /* This sets tsp to sp+1 */
+      return 1; /* initialized */
+   }
+
+   else
+   {
+      int ret = 0; /* unchanged */
+
+      /* An option that is already on the stack; update best_size and best_val
+       * if appropriate.  On the first run there are no previous values and
+       * dp->write_size will be MAX_SIZE, however on the first run dp->tsp
+       * starts off as 0.
+       */
+      assert(dp->write_size > 0U && dp->write_size < MAX_SIZE);
+
+      if (dp->stack[sp].best_size > dp->write_size ||
+          (dp->stack[sp].best_size == dp->write_size &&
+           compare_option(dp, sp) > 0))
+      {
+         dp->stack[sp].best_size = dp->write_size;
+         dp->stack[sp].best_val = dp->value[opt];
+      }
+
+      if (sp+1U >= dp->tsp)
+      {
+         next_opt(dp, sp);
+         ret = 1; /* advanced */
+      }
+
+      else if (!dp->stack[sp].end) /* Active, not at top of stack */
+         dp->nsp = sp+1U;
+
+      return ret; /* advanced || unchanged */
+   }
+}
+
+static int
+getallopts_(struct display *dp, png_byte opt, int *value, int record)
+   /* Like getop but iterate over all the values if the option was set to "all".
+    */
+{
+   if (dp->entry[opt]) /* option was set on command line */
+   {
+      /* Simple, single value, entries don't have a stack frame and have a fixed
+       * value (it doesn't change once set on the command line).  Otherwise the
+       * value (entry) selected from the command line is 'all':
+       */
+      const char *entry_name = options[opt].values[dp->entry[opt]-1].name;
+
+      if (entry_name == all)
+         (void)advance_opt(dp, opt, 0/*do not search; iterate*/);
+
+      else if (record)
+         record_opt(dp, opt, entry_name);
+
+      *value = dp->value[opt];
+      return 1; /* set */
+   }
+
+   else
+      return 0; /* not set */
+}
+
+static int
+getallopts(struct display *dp, const char *opt_str, int *value)
+{
+   return getallopts_(dp, option_index(dp, opt_str, strlen(opt_str)), value, 0);
+}
+
+static int
+getsearchopts(struct display *dp, const char *opt_str, int *value)
+   /* As above except that if the option was not set try a search */
+{
+   png_byte istrat;
+   png_byte opt = option_index(dp, opt_str, strlen(opt_str));
+   int record = options[opt].search;
+   const char *entry_name;
+
+   /* If it was set on the command line honour the setting, including 'all'
+    * which will override the built in search:
+    */
+   if (getallopts_(dp, opt, value, record))
+      return 1;
+
+   else if (!record) /* not a search option */
+      return 0; /* unset and not searched */
+
+   /* Otherwise decide what to do here. */
+   istrat = OPTIND(dp, strategy);
+   entry_name = range_lo; /* record the value, not the name */
+
+   if (opt == istrat) /* search all strategies */
+      (void)advance_opt(dp, opt, 0/*iterate*/), record=0;
+
+   else if (opt == OPTIND(dp, level))
+   {
+      /* Both RLE and HUFFMAN don't benefit from level increases */
+      if (dp->value[istrat] == Z_RLE || dp->value[istrat] == Z_HUFFMAN_ONLY)
+         dp->value[opt] = 1;
+
+      else /* fixed, filtered or default */
+         (void)advance_opt(dp, opt, 1/*search*/), record=0;
+   }
+
+   else if (opt == OPTIND(dp, windowBits))
+   {
+      /* Changing windowBits for strategies that do not search the window is
+       * pointless.  Huffman-only does not search, RLE only searches backwards
+       * one byte, so given that the maximum string length is 258, a windowBits
+       * of 9 is always sufficient.
+       */
+      if (dp->value[istrat] == Z_HUFFMAN_ONLY)
+         dp->value[opt] = 8;
+
+      else if (dp->value[istrat] == Z_RLE)
+         dp->value[opt] = 9;
+
+      else /* fixed, filtered or default */
+         (void)advance_opt(dp, opt, 1/*search*/), record=0;
+   }
+
+   else if (opt == OPTIND(dp, memLevel))
+   {
+#     if 0
+         (void)advance_opt(dp, opt, 0/*all*/), record=0;
+#     else
+         dp->value[opt] = MAX_MEM_LEVEL;
+#     endif
+   }
+
+   else /* something else */
+      assert(0=="reached");
+
+   if (record)
+      record_opt(dp, opt, entry_name);
+
+   /* One of the above searched options: */
+   *value = dp->value[opt];
+   return 1;
+}
+
+static int
+find_val(struct display *dp, png_byte opt, const char *str, size_t len)
+   /* Like option_index but sets (index+i) of the entry in options[opt] that
+    * matches str[0..len-1] into dp->entry[opt] as well as returning the actual
+    * value.
+    */
+{
+   int rlo = INT_MAX, rhi = INT_MIN;
+   png_byte j, irange = 0;
+
+   for (j=1U; j<=options[opt].value_count; ++j)
+   {
+      if (strncmp(options[opt].values[j-1U].name, str, len) == 0 &&
+          options[opt].values[j-1U].name[len] == 0)
+      {
+         dp->entry[opt] = j;
+         return options[opt].values[j-1U].value;
+      }
+      else if (options[opt].values[j-1U].name == range_lo)
+         rlo = options[opt].values[j-1U].value, irange = j;
+      else if (options[opt].values[j-1U].name == range_hi)
+         rhi = options[opt].values[j-1U].value;
+   }
+
+   /* No match on the name, but there may be a range. */
+   if (irange > 0)
+   {
+      char *ep = NULL;
+      long l = strtol(str, &ep, 0);
+
+      if (ep == str+len && l >= rlo && l <= rhi)
+      {
+         dp->entry[opt] = irange; /* range_lo */
+         return (int)/*SAFE*/l;
+      }
+   }
+
+   display_log(dp, dp->errset ? INTERNAL_ERROR : USER_ERROR,
+         "%s: unknown value setting '%.*s'", options[opt].name,
+         (int)/*SAFE*/len, str);
+   abort(); /* NOT REACHED */
+}
+
+static int
+opt_check(struct display *dp, const char *arg)
+{
+   assert(dp->errset == 0);
+
+   if (arg != NULL && arg[0] == '-' && arg[1] == '-')
+   {
+      int i = 0, negate = (strncmp(arg+2, "no-", 3) == 0), val;
+      png_byte j;
+
+      if (negate)
+         arg += 5; /* --no- */
+
+      else
+         arg += 2; /* -- */
+
+      /* Find the length (expect arg\0 or arg=) */
+      while (arg[i] != 0 && arg[i] != '=') ++i;
+
+      /* So arg[0..i-1] is the argument name, this does not return if this isn't
+       * a valid option name.
+       */
+      j = option_index(dp, arg, i);
+
+      /* It matcheth an option; check the remainder. */
+      if (arg[i] == 0) /* no specified value, use the default */
+      {
+         val = options[j].values[negate].value;
+         dp->entry[j] = (png_byte)/*SAFE*/(negate + 1U);
+      }
+
+      else
+      {
+         const char *list = arg + (i+1);
+
+         /* Expect a single value here unless this is a list, in which case
+          * multiple values are combined.
+          */
+         if (options[j].opt != LIST)
+         {
+            /* find_val sets 'dp->entry[j]' to a non-zero value: */
+            val = find_val(dp, j, list, strlen(list));
+
+            if (negate)
+            {
+               if (options[j].opt < OPTION)
+                  val = !val;
+
+               else
+               {
+                  display_log(dp, USER_ERROR,
+                        "%.*s: option=arg cannot be negated", i, arg);
+                  abort(); /* NOT REACHED */
+               }
+            }
+         }
+
+         else /* multiple options separated by ',' characters */
+         {
+            /* --no-option negates list values from the default, which should
+             * therefore be 'all'.  Notice that if the option list is empty in
+             * this case nothing will be removed and therefore --no-option= is
+             * the same as --option.
+             */
+            if (negate)
+               val = options[j].values[0].value;
+
+            else
+               val = 0;
+
+            while (*list != 0) /* allows option= which sets 0 */
+            {
+               /* A value is terminated by the end of the list or a ','
+                * character.
+                */
+               int v, iv;
+
+               iv = 0; /* an index into 'list' */
+               while (list[++iv] != 0 && list[iv] != ',') {}
+
+               v = find_val(dp, j, list, iv);
+
+               if (negate)
+                  val &= ~v;
+
+               else
+                  val |= v;
+
+               list += iv;
+               if (*list != 0)
+                  ++list; /* skip the ',' */
+            }
+         }
+      }
+
+      /* 'val' is the new value, store it for use later and debugging: */
+      dp->value[j] = val;
+
+      if (options[j].opt < LEVEL_MASK)
+      {
+         /* The handling for error levels is to set the level. */
+         if (val) /* Set this level */
+            dp->options = (dp->options & ~LEVEL_MASK) | options[j].opt;
+
+         else
+            display_log(dp, USER_ERROR,
+      "%.*s: messages cannot be turned off individually; set a message level",
+                  i, arg);
+      }
+
+      else if (options[j].opt < OPTION)
+      {
+         if (val)
+            dp->options |= options[j].opt;
+
+         else
+            dp->options &= ~options[j].opt;
+      }
+
+      return 1; /* this is an option */
+   }
+
+   else
+      return 0; /* not an option */
+}
+
+#ifdef PNG_PNGCP_TIMING_SUPPORTED
+static void
+set_timer(struct display *dp, struct timespec *timer)
+{
+   /* Do the timing using clock_gettime and the per-process timer. */
+   if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, timer))
+   {
+      display_log(dp, APP_ERROR,
+            "CLOCK_PROCESS_CPUTIME_ID: %s: timing disabled\n", strerror(errno));
+      dp->value[OPTIND(dp,time)] = 0; /* i.e. off */
+   }
+}
+
+static void
+start_timer(struct display *dp, int what)
+{
+   if ((dp->value[OPTIND(dp,time)] & what) != 0)
+      set_timer(dp, what == PNGCP_TIME_READ ? &dp->read_time : &dp->write_time);
+}
+
+static void
+end_timer(struct display *dp, int what)
+{
+   if ((dp->value[OPTIND(dp,time)] & what) != 0)
+   {
+      struct timespec t, tmp;
+
+      set_timer(dp, &t);
+
+      if (what == PNGCP_TIME_READ)
+         tmp = dp->read_time;
+
+      else
+         tmp = dp->write_time;
+
+      t.tv_sec -= tmp.tv_sec;
+      t.tv_nsec -= tmp.tv_nsec;
+
+      if (t.tv_nsec < 0)
+      {
+         --(t.tv_sec);
+         t.tv_nsec += 1000000000L;
+      }
+
+      if (what == PNGCP_TIME_READ)
+         dp->read_time = t, tmp = dp->read_time_total;
+
+      else
+         dp->write_time = t, tmp = dp->write_time_total;
+
+      tmp.tv_sec += t.tv_sec;
+      tmp.tv_nsec += t.tv_nsec;
+
+      if (tmp.tv_nsec >= 1000000000L)
+      {
+         ++(tmp.tv_sec);
+         tmp.tv_nsec -= 1000000000L;
+      }
+
+      if (what == PNGCP_TIME_READ)
+         dp->read_time_total = tmp;
+
+      else
+         dp->write_time_total = tmp;
+   }
+}
+
+static void
+print_time(const char *what, struct timespec t)
+{
+   printf("%s %.2lu.%.9ld", what, (unsigned long)t.tv_sec, t.tv_nsec);
+}
+#else /* !PNGCP_TIMING */
+#define start_timer(dp, what) ((void)0)
+#define end_timer(dp, what) ((void)0)
+#endif /* !PNGCP_TIMING */
+
+/* The following is used in main to verify that the final argument is a
+ * directory:
+ */
+static int
+checkdir(const char *pathname)
+{
+   struct stat buf;
+   return stat(pathname, &buf) == 0 && S_ISDIR(buf.st_mode);
+}
+
+/* Work out whether a path is valid (if not a display_log occurs), a directory
+ * (1 is returned) or a file *or* non-existent (0 is returned).
+ *
+ * Used for a write path.
+ */
+static int
+isdir(struct display *dp, const char *pathname)
+{
+   if (pathname == NULL)
+      return 0; /* stdout */
+
+   else if (pathname[0] == 0)
+      return 1; /* empty string */
+
+   else
+   {
+      struct stat buf;
+      int ret = stat(pathname, &buf);
+
+      if (ret == 0) /* the entry exists */
+      {
+         if (S_ISDIR(buf.st_mode))
+            return 1;
+
+         /* Else expect an object that exists and can be written: */
+         if (access(pathname, W_OK) != 0)
+            display_log(dp, USER_ERROR, "%s: cannot be written (%s)", pathname,
+                  strerror(errno));
+
+         return 0; /* file (exists, can be written) */
+      }
+
+      else /* an error */
+      {
+         /* Non-existence is fine, other errors are not: */
+         if (errno != ENOENT)
+            display_log(dp, USER_ERROR, "%s: invalid output name (%s)",
+                  pathname, strerror(errno));
+
+         return 0; /* file (does not exist) */
+      }
+   }
+}
+
+static void
+makename(struct display *dp, const char *dir, const char *infile)
+{
+   /* Make a name for an output file (and check it). */
+   dp->namebuf[0] = 0;
+
+   if (dir == NULL || infile == NULL)
+      display_log(dp, INTERNAL_ERROR, "NULL name to makename");
+
+   else
+   {
+      size_t dsize = strlen(dir);
+
+      if (dsize <= (sizeof dp->namebuf)-2) /* Allow for name + '/' + '\0' */
+      {
+         size_t isize = strlen(infile);
+         size_t istart = isize-1;
+
+         /* This should fail before here: */
+         if (infile[istart] == '/')
+            display_log(dp, INTERNAL_ERROR, "infile with trailing /");
+
+         memcpy(dp->namebuf, dir, dsize);
+         if (dsize > 0 && dp->namebuf[dsize-1] != '/')
+            dp->namebuf[dsize++] = '/';
+
+         /* Find the rightmost non-/ character: */
+         while (istart > 0 && infile[istart-1] != '/')
+            --istart;
+
+         isize -= istart;
+         infile += istart;
+
+         if (dsize+isize < (sizeof dp->namebuf)) /* dsize + infile + '\0' */
+         {
+            memcpy(dp->namebuf+dsize, infile, isize+1);
+
+            if (isdir(dp, dp->namebuf))
+               display_log(dp, USER_ERROR, "%s: output file is a directory",
+                     dp->namebuf);
+         }
+
+         else
+         {
+            dp->namebuf[dsize] = 0; /* allowed for: -2 at start */
+            display_log(dp, USER_ERROR, "%s%s: output file name too long",
+                  dp->namebuf, infile);
+         }
+      }
+
+      else
+         display_log(dp, USER_ERROR, "%s: output directory name too long", dir);
+   }
+}
+
+/* error handler callbacks for libpng */
+static void PNGCBAPI
+display_warning(png_structp pp, png_const_charp warning)
+{
+   struct display *dp = get_dp(pp);
+
+   /* This is used to prevent repeated warnings while searching */
+   if (!dp->no_warnings)
+      display_log(get_dp(pp), LIBPNG_WARNING, "%s", warning);
+}
+
+static void PNGCBAPI
+display_error(png_structp pp, png_const_charp error)
+{
+   struct display *dp = get_dp(pp);
+
+   display_log(dp, LIBPNG_ERROR, "%s", error);
+}
+
+static void
+display_start_read(struct display *dp, const char *filename)
+{
+   if (filename != NULL)
+   {
+      dp->filename = filename;
+      dp->fp = fopen(filename, "rb");
+   }
+
+   else
+   {
+      dp->filename = "<stdin>";
+      dp->fp = stdin;
+   }
+
+   dp->w = dp->h = 0U;
+   dp->bpp = 0U;
+   dp->size = 0U;
+   dp->read_size = 0U;
+
+   if (dp->fp == NULL)
+      display_log(dp, USER_ERROR, "file open failed (%s)", strerror(errno));
+}
+
+static void PNGCBAPI
+read_function(png_structp pp, png_bytep data, size_t size)
+{
+   struct display *dp = get_dp(pp);
+
+   if (size == 0U || fread(data, size, 1U, dp->fp) == 1U)
+      dp->read_size += size;
+
+   else
+   {
+      if (feof(dp->fp))
+         display_log(dp, LIBPNG_ERROR, "PNG file truncated");
+      else
+         display_log(dp, LIBPNG_ERROR, "PNG file read failed (%s)",
+               strerror(errno));
+   }
+}
+
+static void
+read_png(struct display *dp, const char *filename)
+{
+   /* This is an assumption of the code; it may happen if a previous write fails
+    * and there is a bug in the cleanup handling below (look for setjmp).
+    * Passing freeinfo==1 to display_clean_read below avoids a second error
+    * on dp->ip != NULL below.
+    */
+   if (dp->read_pp != NULL)
+   {
+      display_log(dp, APP_FAIL, "unexpected png_read_struct");
+      display_clean_read(dp, 1/*freeinfo*/); /* recovery */
+   }
+
+   display_start_read(dp, filename);
+
+   dp->read_pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, dp,
+      display_error, display_warning);
+   if (dp->read_pp == NULL)
+      display_log(dp, LIBPNG_ERROR, "failed to create read struct");
+
+#  ifdef PNG_BENIGN_ERRORS_SUPPORTED
+      png_set_benign_errors(dp->read_pp, 1/*allowed*/);
+#  endif /* BENIGN_ERRORS */
+
+#  ifdef FIX_INDEX
+      if ((dp->options & FIX_INDEX) != 0)
+         png_set_check_for_invalid_index(dp->read_pp, 1/*on, no warning*/);
+#     ifdef IGNORE_INDEX
+         else
+#     endif /* IGNORE_INDEX */
+#  endif /* FIX_INDEX */
+#  ifdef IGNORE_INDEX
+      if ((dp->options & IGNORE_INDEX) != 0) /* DANGEROUS */
+         png_set_check_for_invalid_index(dp->read_pp, -1/*off completely*/);
+#  endif /* IGNORE_INDEX */
+
+   if (dp->ip != NULL)
+   {
+      /* UNEXPECTED: some problem in the display_clean function calls! */
+      display_log(dp, APP_FAIL, "read_png: freeing old info struct");
+      png_destroy_info_struct(dp->read_pp, &dp->ip);
+   }
+
+   /* The png_read_png API requires us to make the info struct, but it does the
+    * call to png_read_info.
+    */
+   dp->ip = png_create_info_struct(dp->read_pp);
+   if (dp->ip == NULL)
+      png_error(dp->read_pp, "failed to create info struct");
+
+   /* Set the IO handling */
+   png_set_read_fn(dp->read_pp, dp, read_function);
+
+#  ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      png_set_keep_unknown_chunks(dp->read_pp, PNG_HANDLE_CHUNK_ALWAYS, NULL,
+            0);
+#  endif /* HANDLE_AS_UNKNOWN */
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      /* Remove the user limits, if any */
+      png_set_user_limits(dp->read_pp, 0x7fffffff, 0x7fffffff);
+#  endif /* SET_USER_LIMITS */
+
+   /* Now read the PNG. */
+   start_timer(dp, PNGCP_TIME_READ);
+   png_read_png(dp->read_pp, dp->ip, 0U/*transforms*/, NULL/*params*/);
+   end_timer(dp, PNGCP_TIME_READ);
+   dp->w = png_get_image_width(dp->read_pp, dp->ip);
+   dp->h = png_get_image_height(dp->read_pp, dp->ip);
+   dp->ct = png_get_color_type(dp->read_pp, dp->ip);
+   dp->bpp = png_get_bit_depth(dp->read_pp, dp->ip) *
+             png_get_channels(dp->read_pp, dp->ip);
+   {
+      /* png_get_rowbytes should never return 0 because the value is set by the
+       * first call to png_set_IHDR, which should have happened by now, but just
+       * in case:
+       */
+      png_alloc_size_t rb = png_get_rowbytes(dp->read_pp, dp->ip);
+
+      if (rb == 0)
+         png_error(dp->read_pp, "invalid row byte count from libpng");
+
+      /* The size calc can overflow. */
+      if ((MAX_SIZE-dp->h)/rb < dp->h)
+         png_error(dp->read_pp, "image too large");
+
+      dp->size = rb * dp->h + dp->h/*filter byte*/;
+   }
+
+#ifdef FIX_INDEX
+   if (dp->ct == PNG_COLOR_TYPE_PALETTE && (dp->options & FIX_INDEX) != 0)
+   {
+      int max = png_get_palette_max(dp->read_pp, dp->ip);
+      png_colorp palette = NULL;
+      int num = -1;
+
+      if (png_get_PLTE(dp->read_pp, dp->ip, &palette, &num) != PNG_INFO_PLTE
+          || max < 0 || num <= 0 || palette == NULL)
+         display_log(dp, LIBPNG_ERROR, "invalid png_get_PLTE result");
+
+      if (max >= num)
+      {
+         /* 'Fix' the palette. */
+         int i;
+         png_color newpal[256];
+
+         for (i=0; i<num; ++i)
+            newpal[i] = palette[i];
+
+         /* Fill in any remainder with a warning color: */
+         for (; i<=max; ++i)
+         {
+            newpal[i].red = 0xbe;
+            newpal[i].green = 0xad;
+            newpal[i].blue = 0xed;
+         }
+
+         png_set_PLTE(dp->read_pp, dp->ip, newpal, i);
+      }
+   }
+#endif /* FIX_INDEX */
+
+   /* NOTE: dp->ip is where all the information about the PNG that was just read
+    * is stored.  It can be used to write and write again a single PNG file,
+    * however be aware that prior to libpng 1.7 text chunks could only be
+    * written once; this is a bug which would require a significant code rewrite
+    * to fix, it has been there in several versions of libpng (it was introduced
+    * to fix another bug involving duplicate writes of the text chunks.)
+    */
+   display_clean_read(dp, 0/*freeiinfo*/);
+   dp->operation = "none";
+}
+
+static void
+display_start_write(struct display *dp, const char *filename)
+{
+   assert(dp->fp == NULL);
+
+   if ((dp->options & NOWRITE) != 0)
+      dp->output_file = "<no write>";
+
+   else
+   {
+      if (filename != NULL)
+      {
+         dp->output_file = filename;
+         dp->fp = fopen(filename, "wb");
+      }
+
+      else
+      {
+         dp->output_file = "<stdout>";
+         dp->fp = stdout;
+      }
+
+      if (dp->fp == NULL)
+         display_log(dp, USER_ERROR, "%s: file open failed (%s)",
+               dp->output_file, strerror(errno));
+   }
+}
+
+static void PNGCBAPI
+write_function(png_structp pp, png_bytep data, size_t size)
+{
+   struct display *dp = get_dp(pp);
+
+   /* The write fail is classed as a USER_ERROR, so --quiet does not turn it
+    * off, this seems more likely to be correct.
+    */
+   if (dp->fp == NULL || fwrite(data, size, 1U, dp->fp) == 1U)
+   {
+      dp->write_size += size;
+      if (dp->write_size < size || dp->write_size == MAX_SIZE)
+         png_error(pp, "IDAT size overflow");
+   }
+
+   else
+      display_log(dp, USER_ERROR, "%s: PNG file write failed (%s)",
+            dp->output_file, strerror(errno));
+}
+
+/* Compression option, 'method' is never set: there is no choice.
+ *
+ * IMPORTANT: the order of the entries in this macro determines the preference
+ * order when two different combos of two of these options produce an IDAT of
+ * the same size.  The logic here is to put the things that affect the decoding
+ * of the PNG image ahead of those that are relevant only to the encoding.
+ */
+#define SET_COMPRESSION\
+   SET(strategy, strategy);\
+   SET(windowBits, window_bits);\
+   SET(level, level);\
+   SET(memLevel, mem_level);
+
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+static void
+search_compression(struct display *dp)
+{
+   /* Like set_compression below but use a more restricted search than 'all' */
+   int val;
+
+#  define SET(name, func) if (getsearchopts(dp, #name, &val))\
+      png_set_compression_ ## func(dp->write_pp, val);
+   SET_COMPRESSION
+#  undef SET
+}
+
+static void
+set_compression(struct display *dp)
+{
+   int val;
+
+#  define SET(name, func) if (getallopts(dp, #name, &val))\
+      png_set_compression_ ## func(dp->write_pp, val);
+   SET_COMPRESSION
+#  undef SET
+}
+
+#ifdef PNG_SW_COMPRESS_level /* 1.7.0+ */
+static void
+set_ICC_profile_compression(struct display *dp)
+{
+   int val;
+
+#  define SET(name, func) if (getallopts(dp, "ICC-profile-" #name, &val))\
+      png_set_ICC_profile_compression_ ## func(dp->write_pp, val);
+   SET_COMPRESSION
+#  undef SET
+}
+#else
+#  define set_ICC_profile_compression(dp) ((void)0)
+#endif
+#else
+#  define search_compression(dp) ((void)0)
+#  define set_compression(dp) ((void)0)
+#  define set_ICC_profile_compression(dp) ((void)0)
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+static void
+set_text_compression(struct display *dp)
+{
+   int val;
+
+#  define SET(name, func) if (getallopts(dp, "text-" #name, &val))\
+      png_set_text_compression_ ## func(dp->write_pp, val);
+   SET_COMPRESSION
+#  undef SET
+}
+#else
+#  define set_text_compression(dp) ((void)0)
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+
+static void
+write_png(struct display *dp, const char *destname)
+{
+   /* If this test fails png_write_png would fail *silently* below; this
+    * is not helpful, so catch the problem now and give up:
+    */
+   if (dp->ip == NULL)
+      display_log(dp, INTERNAL_ERROR, "missing png_info");
+
+   /* This is an assumption of the code; it may happen if a previous
+    * write fails and there is a bug in the cleanup handling below.
+    */
+   if (dp->write_pp != NULL)
+   {
+      display_log(dp, APP_FAIL, "unexpected png_write_struct");
+      display_clean_write(dp, 0/*!freeinfo*/);
+   }
+
+   display_start_write(dp, destname);
+
+   dp->write_pp = png_create_write_struct(PNG_LIBPNG_VER_STRING, dp,
+      display_error, display_warning);
+
+   if (dp->write_pp == NULL)
+      display_log(dp, LIBPNG_ERROR, "failed to create write png_struct");
+
+#  ifdef PNG_BENIGN_ERRORS_SUPPORTED
+      png_set_benign_errors(dp->write_pp, 1/*allowed*/);
+#  endif /* BENIGN_ERRORS */
+
+   png_set_write_fn(dp->write_pp, dp, write_function, NULL/*flush*/);
+
+#ifdef IGNORE_INDEX
+   if ((dp->options & IGNORE_INDEX) != 0) /* DANGEROUS */
+      png_set_check_for_invalid_index(dp->write_pp, -1/*off completely*/);
+#endif /* IGNORE_INDEX */
+
+   /* Restore the text chunks when using libpng 1.6 or less; this is a macro
+    * which expands to nothing in 1.7+  In earlier versions it tests
+    * dp->text_stashed, which is only set (below) *after* the first write.
+    */
+   text_restore(dp);
+
+#  ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      png_set_keep_unknown_chunks(dp->write_pp, PNG_HANDLE_CHUNK_ALWAYS, NULL,
+            0);
+#  endif /* HANDLE_AS_UNKNOWN */
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      /* Remove the user limits, if any */
+      png_set_user_limits(dp->write_pp, 0x7fffffff, 0x7fffffff);
+#  endif
+
+   /* OPTION HANDLING */
+   /* compression outputs, IDAT and zTXt/iTXt: */
+   dp->tsp = dp->nsp;
+   dp->nsp = dp->csp = 0;
+#  ifdef PNG_SW_COMPRESS_png_level
+      {
+         int val;
+
+         /* This sets everything, but then the following options just override
+          * the specific settings for ICC profiles and text.
+          */
+         if (getallopts(dp, "compression", &val))
+            png_set_compression(dp->write_pp, val);
+
+         if (getallopts(dp, "ICC-profile-compression", &val))
+            png_set_ICC_profile_compression(dp->write_pp, val);
+
+         if (getallopts(dp, "text-compression", &val))
+            png_set_text_compression(dp->write_pp, val);
+      }
+#  endif /* png_level support */
+   if (dp->options & SEARCH)
+      search_compression(dp);
+   else
+      set_compression(dp);
+   set_ICC_profile_compression(dp);
+   set_text_compression(dp);
+
+   {
+      int val;
+
+      /* The permitted range is 1..0x7FFFFFFF, so the cast is safe */
+      if (get_option(dp, "IDAT-size", &val))
+         png_set_IDAT_size(dp->write_pp, val);
+   }
+
+   /* filter handling */
+#  ifdef PNG_WRITE_FILTER_SUPPORTED
+      {
+         int val;
+
+         if (get_option(dp, "filter", &val))
+            png_set_filter(dp->write_pp, PNG_FILTER_TYPE_BASE, val);
+      }
+#  endif /* WRITE_FILTER */
+
+   /* This just uses the 'read' info_struct directly, it contains the image. */
+   dp->write_size = 0U;
+   start_timer(dp, PNGCP_TIME_WRITE);
+   png_write_png(dp->write_pp, dp->ip, 0U/*transforms*/, NULL/*params*/);
+   end_timer(dp, PNGCP_TIME_WRITE);
+
+   /* Make sure the file was written ok: */
+   if (dp->fp != NULL)
+   {
+      FILE *fp = dp->fp;
+      dp->fp = NULL;
+      if (fclose(fp))
+         display_log(dp, APP_ERROR, "%s: write failed (%s)",
+               destname == NULL ? "stdout" : destname, strerror(errno));
+   }
+
+   dp->operation = "none";
+}
+
+static void
+set_windowBits_hi(struct display *dp)
+{
+   /* windowBits is in the range 8..15 but zlib maps '8' to '9' so it is only
+    * worth using if the data size is 256 byte or less.
+    */
+   int wb = MAX_WBITS; /* for large images */
+   int i = VLSIZE(windowBits_IDAT);
+
+   while (wb > 8 && dp->size <= 1U<<(wb-1)) --wb;
+
+   while (--i >= 0) if (VLNAME(windowBits_IDAT)[i].name == range_hi) break;
+
+   assert(i > 1); /* vl_windowBits_IDAT always has a RANGE() */
+   VLNAME(windowBits_IDAT)[i].value = wb;
+
+   assert(VLNAME(windowBits_IDAT)[--i].name == range_lo);
+   VLNAME(windowBits_IDAT)[i].value = wb > 8 ? 9 : 8;
+
+   /* If wb == 8 then any search has been restricted to just one windowBits
+    * entry.  Record that here to avoid producing a spurious app-level warning
+    * above.
+    */
+   if (wb == 8)
+      dp->min_windowBits = OPTIND(dp, windowBits);
+}
+
+static int
+better_options(const struct display *dp)
+{
+   /* Are these options better than the best found so far?  Normally the
+    * options are tested in preference order, best first, however when doing a
+    * search operation on a range the range values are tested out of order.  In
+    * that case preferable options will get tested later.
+    *
+    * This function looks through the stack from the bottom up looking for an
+    * option that does not match the current best value.  When it finds one it
+    * checks to see if it is more or less desirable and returns true or false
+    * as appropriate.
+    *
+    * Notice that this means that the order options are pushed onto the stack
+    * conveys a priority; lower/earlier options are more important than later
+    * ones.
+    */
+   unsigned int sp;
+
+   for (sp=0; sp<dp->csp; ++sp)
+   {
+      int c = compare_option(dp, sp);
+
+      if (c < 0)
+         return 0; /* worse */
+
+      else if (c > 0)
+         return 1; /* better */
+   }
+
+   assert(0 && "unreached");
+}
+
+static void
+print_search_results(struct display *dp)
+{
+   assert(dp->filename != NULL);
+   printf("%s [%ld x %ld %d bpp %s, %lu bytes] %lu -> %lu with '%s'\n",
+      dp->filename, (unsigned long)dp->w, (unsigned long)dp->h, dp->bpp,
+      cts(dp->ct), (unsigned long)dp->size, (unsigned long)dp->read_size,
+      (unsigned long)dp->best_size, dp->best);
+   fflush(stdout);
+}
+
+static void
+log_search(struct display *dp, unsigned int log_depth)
+{
+   /* Log, and reset, the search so far: */
+   if (dp->nsp/*next entry to change*/ <= log_depth)
+   {
+      print_search_results(dp);
+      /* Start again with this entry: */
+      dp->best_size = MAX_SIZE;
+   }
+}
+
+static void
+cp_one_file(struct display *dp, const char *filename, const char *destname)
+{
+   unsigned int log_depth;
+
+   dp->filename = filename;
+   dp->operation = "read";
+   dp->no_warnings = 0;
+
+   /* Read it then write it: */
+   if (filename != NULL && access(filename, R_OK) != 0)
+      display_log(dp, USER_ERROR, "%s: invalid file name (%s)",
+            filename, strerror(errno));
+
+   read_png(dp, filename);
+
+   /* But 'destname' may be a directory. */
+   dp->operation = "write";
+
+   /* Limit the upper end of the windowBits range for this file */
+   set_windowBits_hi(dp);
+
+   /* For logging, depth to log: */
+   {
+      int val;
+
+      if (get_option(dp, "log-depth", &val) && val >= 0)
+         log_depth = (unsigned int)/*SAFE*/val;
+
+      else
+         log_depth = 0U;
+   }
+
+   if (destname != NULL) /* else stdout */
+   {
+      if (isdir(dp, destname))
+      {
+         makename(dp, destname, filename);
+         destname = dp->namebuf;
+      }
+
+      else if (access(destname, W_OK) != 0 && errno != ENOENT)
+         display_log(dp, USER_ERROR, "%s: invalid output name (%s)", destname,
+               strerror(errno));
+   }
+
+   dp->nsp = 0;
+   dp->curr[0] = 0; /* acts as a flag for the caller */
+   dp->opt_string_start = 0;
+   dp->best[0] = 0; /* safety */
+   dp->best_size = MAX_SIZE;
+   write_png(dp, destname);
+
+   /* Initialize the 'best' fields: */
+   strcpy(dp->best, dp->curr);
+   dp->best_size = dp->write_size;
+
+   if (dp->nsp > 0) /* iterating over lists */
+   {
+      char *tmpname, tmpbuf[(sizeof dp->namebuf) + 4];
+      assert(dp->curr[0] == ' ' && dp->tsp > 0);
+
+      /* Cancel warnings on subsequent writes */
+      log_search(dp, log_depth);
+      dp->no_warnings = 1;
+
+      /* Make a temporary name for the subsequent tests: */
+      if (destname != NULL)
+      {
+         strcpy(tmpbuf, destname);
+         strcat(tmpbuf, ".tmp"); /* space for .tmp allocated above */
+         tmpname = tmpbuf;
+      }
+
+      else
+         tmpname = NULL; /* stdout */
+
+      /* Loop to find the best option. */
+      do
+      {
+         /* Clean before each write_png; this just removes *dp->write_pp which
+          * cannot be reused.
+          */
+         display_clean_write(dp, 0/*!freeinfo*/);
+         write_png(dp, tmpname);
+
+         /* And compare the sizes (the write function makes sure write_size
+          * doesn't overflow.)
+          */
+         assert(dp->csp > 0);
+
+         if (dp->write_size < dp->best_size ||
+             (dp->write_size == dp->best_size && better_options(dp)))
+         {
+            if (destname != NULL && rename(tmpname, destname) != 0)
+               display_log(dp, APP_ERROR, "rename %s %s failed (%s)", tmpname,
+                     destname, strerror(errno));
+
+            strcpy(dp->best, dp->curr);
+            dp->best_size = dp->write_size;
+         }
+
+         else if (tmpname != NULL && unlink(tmpname) != 0)
+            display_log(dp, APP_WARNING, "unlink %s failed (%s)", tmpname,
+                  strerror(errno));
+
+         log_search(dp, log_depth);
+      }
+      while (dp->nsp > 0);
+
+      /* Do this for the 'sizes' option so that it reports the correct size. */
+      dp->write_size = dp->best_size;
+   }
+
+   display_clean_write(dp, 1/*freeinfo*/);
+}
+
+static int
+cppng(struct display *dp, const char *file, const char *dest)
+{
+   if (setjmp(dp->error_return) == 0)
+   {
+      dp->errset = 1;
+      cp_one_file(dp, file, dest);
+      dp->errset = 0;
+      return 0;
+   }
+
+   else
+   {
+      dp->errset = 0;
+
+      if (dp->errlevel < ERRORS) /* shouldn't longjmp on warnings */
+         display_log(dp, INTERNAL_ERROR, "unexpected return code %d",
+               dp->errlevel);
+
+      return dp->errlevel;
+   }
+}
+
+int
+main(int argc, char **argv)
+{
+   /* For each file on the command line test it with a range of transforms */
+   int option_end;
+   struct display d;
+
+   display_init(&d);
+
+   d.operation = "options";
+   for (option_end = 1;
+        option_end < argc && opt_check(&d, argv[option_end]);
+        ++option_end)
+   {
+   }
+
+   /* Do a quick check on the directory target case; when there are more than
+    * two arguments the last one must be a directory.
+    */
+   if (!(d.options & NOWRITE) && option_end+2 < argc && !checkdir(argv[argc-1]))
+   {
+      fprintf(stderr,
+            "pngcp: %s: directory required with more than two arguments\n",
+            argv[argc-1]);
+      return 99;
+   }
+
+   {
+      int errors = 0;
+      int i = option_end;
+
+      /* Do this at least once; if there are no arguments stdin/stdout are used.
+       */
+      d.operation = "files";
+      do
+      {
+         const char *infile = NULL;
+         const char *outfile = NULL;
+         int ret;
+
+         if (i < argc)
+         {
+            infile = argv[i++];
+            if (!(d.options & NOWRITE) && i < argc)
+               outfile = argv[argc-1];
+         }
+
+         ret = cppng(&d, infile, outfile);
+
+         if (ret)
+         {
+            if (ret > QUIET) /* abort on user or internal error */
+               return 99;
+
+            /* An error: the output is meaningless */
+         }
+
+         else if (d.best[0] != 0)
+         {
+            /* This result may already have been output, in which case best_size
+             * has been reset.
+             */
+            if (d.best_size < MAX_SIZE)
+               print_search_results(&d);
+         }
+
+         else if (d.options & SIZES)
+         {
+            printf("%s [%ld x %ld %d bpp %s, %lu bytes] %lu -> %lu [0x%lx]\n",
+                  infile, (unsigned long)d.w, (unsigned long)d.h, d.bpp,
+                  cts(d.ct), (unsigned long)d.size, (unsigned long)d.read_size,
+                  (unsigned long)d.write_size, (unsigned long)d.results);
+            fflush(stdout);
+         }
+
+         /* Here on any return, including failures, except user/internal issues
+          */
+         {
+            int pass = (d.options & STRICT) ?
+               RESULT_STRICT(d.results) : RESULT_RELAXED(d.results);
+
+            if (!pass)
+               ++errors;
+
+            if (d.options & LOG)
+            {
+               int j;
+
+               printf("%s: pngcp", pass ? "PASS" : "FAIL");
+
+               for (j=1; j<option_end; ++j)
+                  printf(" %s", argv[j]);
+
+               if (infile != NULL)
+                  printf(" %s", infile);
+
+#              ifdef PNG_PNGCP_TIMING_SUPPORTED
+                  /* When logging output the files for each file, if enabled. */
+                  if ((d.value[OPTIND(&d,time)] & PNGCP_TIME_READ) != 0)
+                     print_time(" read", d.read_time);
+
+                  if ((d.value[OPTIND(&d,time)] & PNGCP_TIME_WRITE) != 0)
+                     print_time(" write", d.write_time);
+#              endif /* PNGCP_TIMING */
+
+               printf("\n");
+               fflush(stdout);
+            }
+         }
+
+         display_clean(&d);
+      }
+      while (i+!(d.options & NOWRITE) < argc);
+         /* I.e. for write cases after the first time through the loop require
+          * there to be at least two arguments left and for the last one to be a
+          * directory (this was checked above).
+          */
+
+      /* Release allocated memory */
+      display_destroy(&d);
+
+#     ifdef PNG_PNGCP_TIMING_SUPPORTED
+         {
+            int output = 0;
+
+            if ((d.value[OPTIND(&d,time)] & PNGCP_TIME_READ) != 0)
+               print_time("read", d.read_time_total), output = 1;
+
+            if ((d.value[OPTIND(&d,time)] & PNGCP_TIME_WRITE) != 0)
+            {
+               if (output) putchar(' ');
+               print_time("write", d.write_time_total);
+               output = 1;
+            }
+
+            if (output) putchar('\n');
+         }
+#     endif /* PNGCP_TIMING */
+
+      return errors != 0;
+   }
+}
+#else /* !READ_PNG || !WRITE_PNG */
+int
+main(void)
+{
+   fprintf(stderr, "pngcp: no support for png_read/write_image\n");
+   return 77;
+}
+#endif /* !READ_PNG || !WRITE_PNG */
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/pngfix.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/pngfix.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/pngfix.c	(revision 107811)
@@ -0,0 +1,4047 @@
+/* pngfix.c
+ *
+ * Copyright (c) 2014-2017,2024 John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Tool to check and fix the zlib inflate 'too far back' problem.
+ * See the usage message for more information.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.h>
+#include <errno.h>
+#include <assert.h>
+
+#define implies(x,y) assert(!(x) || (y))
+
+#define PROGRAM_NAME "pngfix"
+
+/* Define the following to use this program against your installed libpng,
+ * rather than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#if PNG_LIBPNG_VER < 10603 /* 1.6.3 */
+#  error "pngfix will not work with libpng prior to 1.6.3"
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+#include <setjmp.h>
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_EASY_ACCESS_SUPPORTED) &&\
+   (defined(PNG_READ_DEINTERLACE_SUPPORTED) ||\
+    defined(PNG_READ_INTERLACING_SUPPORTED))
+
+/* zlib.h defines the structure z_stream, an instance of which is included
+ * in this structure and is required for decompressing the LZ compressed
+ * data in PNG files.
+ */
+#ifndef ZLIB_CONST
+   /* We must ensure that zlib uses 'const' in declarations. */
+#  define ZLIB_CONST
+#endif
+#include <zlib.h>
+#ifdef const
+   /* zlib.h sometimes #defines const to nothing, undo this. */
+#  undef const
+#endif
+
+/* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
+ * with older builds.
+ */
+#if ZLIB_VERNUM < 0x1260
+#  define PNGZ_MSG_CAST(s) constcast(char*,s)
+#  define PNGZ_INPUT_CAST(b) constcast(png_bytep,b)
+#else
+#  define PNGZ_MSG_CAST(s) (s)
+#  define PNGZ_INPUT_CAST(b) (b)
+#endif
+
+#ifndef PNG_MAXIMUM_INFLATE_WINDOW
+#  error "pngfix not supported in this libpng version"
+#endif
+
+#if ZLIB_VERNUM >= 0x1240
+
+/* Copied from pngpriv.h */
+#ifdef __cplusplus
+#  define voidcast(type, value) static_cast<type>(value)
+#  define constcast(type, value) const_cast<type>(value)
+#  define aligncast(type, value) \
+   static_cast<type>(static_cast<void*>(value))
+#  define aligncastconst(type, value) \
+   static_cast<type>(static_cast<const void*>(value))
+#else
+#  define voidcast(type, value) (value)
+#  define constcast(type, value) ((type)(value))
+#  define aligncast(type, value) ((void*)(value))
+#  define aligncastconst(type, value) ((const void*)(value))
+#endif /* __cplusplus */
+
+#if PNG_LIBPNG_VER < 10700
+/* Chunk tags (copied from pngpriv.h) */
+#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
+#define PNG_U32(b1,b2,b3,b4) \
+   (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
+
+/* Constants for known chunk types. */
+#define png_IDAT PNG_U32( 73,  68,  65,  84)
+#define png_IEND PNG_U32( 73,  69,  78,  68)
+#define png_IHDR PNG_U32( 73,  72,  68,  82)
+#define png_PLTE PNG_U32( 80,  76,  84,  69)
+#define png_bKGD PNG_U32( 98,  75,  71,  68)
+#define png_cHRM PNG_U32( 99,  72,  82,  77)
+#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
+#define png_gAMA PNG_U32(103,  65,  77,  65)
+#define png_gIFg PNG_U32(103,  73,  70, 103)
+#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
+#define png_gIFx PNG_U32(103,  73,  70, 120)
+#define png_hIST PNG_U32(104,  73,  83,  84)
+#define png_iCCP PNG_U32(105,  67,  67,  80)
+#define png_iTXt PNG_U32(105,  84,  88, 116)
+#define png_oFFs PNG_U32(111,  70,  70, 115)
+#define png_pCAL PNG_U32(112,  67,  65,  76)
+#define png_pHYs PNG_U32(112,  72,  89, 115)
+#define png_sBIT PNG_U32(115,  66,  73,  84)
+#define png_sCAL PNG_U32(115,  67,  65,  76)
+#define png_sPLT PNG_U32(115,  80,  76,  84)
+#define png_sRGB PNG_U32(115,  82,  71,  66)
+#define png_sTER PNG_U32(115,  84,  69,  82)
+#define png_tEXt PNG_U32(116,  69,  88, 116)
+#define png_tIME PNG_U32(116,  73,  77,  69)
+#define png_tRNS PNG_U32(116,  82,  78,  83)
+#define png_zTXt PNG_U32(122,  84,  88, 116)
+#endif
+
+/* The 8-byte signature as a pair of 32-bit quantities */
+#define sig1 PNG_U32(137,  80,  78,  71)
+#define sig2 PNG_U32( 13,  10,  26,  10)
+
+/* Is the chunk critical? */
+#define CRITICAL(chunk) (((chunk) & PNG_U32(32,0,0,0)) == 0)
+
+/* Is it safe to copy? */
+#define SAFE_TO_COPY(chunk) (((chunk) & PNG_U32(0,0,0,32)) != 0)
+
+/********************************* UTILITIES **********************************/
+/* UNREACHED is a value to cause an assert to fail. Because of the way the
+ * assert macro is written the string "UNREACHED" is produced in the error
+ * message.
+ */
+#define UNREACHED 0
+
+/* 80-bit number handling - a PNG image can be up to (2^31-1)x(2^31-1) 8-byte
+ * (16-bit RGBA) pixels in size; that's less than 2^65 bytes or 2^68 bits, so
+ * arithmetic of 80-bit numbers is sufficient.  This representation uses an
+ * arbitrary length array of png_uint_16 digits (0..65535).  The representation
+ * is little endian.
+ *
+ * The arithmetic functions take zero to two uarb values together with the
+ * number of digits in those values and write the result to the given uarb
+ * (always the first argument) returning the number of digits in the result.
+ * If the result is negative the return value is also negative (this would
+ * normally be an error).
+ */
+typedef png_uint_16  udigit; /* A 'unum' is an array of these */
+typedef png_uint_16p uarb;
+typedef png_const_uint_16p uarbc;
+
+#define UDIGITS(unum) ((sizeof unum)/(sizeof (udigit))
+   /* IMPORTANT: only apply this to an array, applied to a pointer the result
+    * will typically be '2', which is not useful.
+    */
+
+static int
+uarb_set(uarb result, png_alloc_size_t val)
+   /* Set (initialize) 'result' to 'val'.  The size required for 'result' must
+    * be determined by the caller from a knowledge of the maximum for 'val'.
+    */
+{
+   int ndigits = 0;
+
+   while (val > 0)
+   {
+      result[ndigits++] = (png_uint_16)(val & 0xffff);
+      val >>= 16;
+   }
+
+   return ndigits;
+}
+
+static int
+uarb_copy(uarb to, uarb from, int idigits)
+   /* Copy a uarb, may reduce the digit count */
+{
+   int d, odigits;
+
+   for (d=odigits=0; d<idigits; ++d)
+      if ((to[d] = from[d]) != 0)
+         odigits = d+1;
+
+   return odigits;
+}
+
+static int
+uarb_inc(uarb num, int in_digits, png_int_32 add)
+   /* This is a signed 32-bit add, except that to avoid overflow the value added
+    * or subtracted must be no more than 2^31-65536.  A negative result
+    * indicates a negative number (which is an error below).  The size of
+    * 'num' should be max(in_digits+1,2) for arbitrary 'add' but can be just
+    * in_digits+1 if add is known to be in the range -65535..65535.
+    */
+{
+   int out_digits = 0;
+
+   while (out_digits < in_digits)
+   {
+      add += num[out_digits];
+      num[out_digits++] = (png_uint_16)(add & 0xffff);
+      add >>= 16;
+   }
+
+   while (add != 0 && add != (-1))
+   {
+      num[out_digits++] = (png_uint_16)(add & 0xffff);
+      add >>= 16;
+   }
+
+   if (add == 0)
+   {
+      while (out_digits > 0 && num[out_digits-1] == 0)
+         --out_digits;
+      return out_digits; /* may be 0 */
+   }
+
+   else /* negative result */
+   {
+      while (out_digits > 1 && num[out_digits-1] == 0xffff)
+         --out_digits;
+
+      return -out_digits;
+   }
+}
+
+static int
+uarb_add32(uarb num, int in_digits, png_uint_32 add)
+   /* As above but this works with any 32-bit value and only does 'add' */
+{
+   if (in_digits > 0)
+   {
+      in_digits = uarb_inc(num, in_digits, add & 0xffff);
+      return uarb_inc(num+1, in_digits-1, add >> 16)+1;
+   }
+
+   return uarb_set(num, add);
+}
+
+static int
+uarb_mult_digit(uarb acc, int a_digits, uarb num, int n_digits,
+   png_uint_16 val)
+   /* Primitive one-digit multiply - 'val' must be 0..65535. Note that this
+    * primitive is a multiply and accumulate - the result of *num * val is added
+    * to *acc.
+    *
+    * This is a one-digit multiply, so the product may be up to one digit longer
+    * than 'num', however the add to 'acc' means that the caller must ensure
+    * that 'acc' is at least one digit longer than this *and* at least one digit
+    * longer than the current length of 'acc'.  (Or the caller must otherwise
+    * ensure 'adigits' is adequate from knowledge of the values.)
+    */
+{
+   /* The digits in *acc, *num and val are in the range 0..65535, so the
+    * result below is at most (65535*65535)+2*65635 = 65535*(65535+2), which is
+    * exactly 0xffffffff.
+    */
+   if (val > 0 && n_digits > 0) /* Else the product is 0 */
+   {
+      png_uint_32 carry = 0;
+      int out_digits = 0;
+
+      while (out_digits < n_digits || carry > 0)
+      {
+         if (out_digits < a_digits)
+            carry += acc[out_digits];
+
+         if (out_digits < n_digits)
+            carry += (png_uint_32)num[out_digits] * val;
+
+         acc[out_digits++] = (png_uint_16)(carry & 0xffff);
+         carry >>= 16;
+      }
+
+      /* So carry is 0 and all the input digits have been consumed. This means
+       * that it is possible to skip any remaining digits in acc.
+       */
+      if (out_digits > a_digits)
+         return out_digits;
+   }
+
+   return a_digits;
+}
+
+static int
+uarb_mult32(uarb acc, int a_digits, uarb num, int n_digits, png_uint_32 val)
+   /* calculate acc += num * val, 'val' may be any 32-bit value, 'acc' and 'num'
+    * may be any value, returns the number of digits in 'acc'.
+    */
+{
+   if (n_digits > 0 && val > 0)
+   {
+      a_digits = uarb_mult_digit(acc, a_digits, num, n_digits,
+         (png_uint_16)(val & 0xffff));
+
+      val >>= 16;
+      if (val > 0)
+         a_digits = uarb_mult_digit(acc+1, a_digits-1, num, n_digits,
+            (png_uint_16)val) + 1;
+
+      /* Because n_digits and val are >0 the following must be true: */
+      assert(a_digits > 0);
+   }
+
+   return a_digits;
+}
+
+static int
+uarb_shift(uarb inout, int ndigits, unsigned int right_shift)
+   /* Shift inout right by right_shift bits, right_shift must be in the range
+    * 1..15
+    */
+{
+   int i = ndigits;
+   png_uint_16 carry = 0;
+
+   assert(right_shift >= 1 && right_shift <= 15);
+
+   while (--i >= 0)
+   {
+      png_uint_16 temp = (png_uint_16)(carry | (inout[i] >> right_shift));
+
+      /* Bottom bits to top bits of carry */
+      carry = (png_uint_16)((inout[i] << (16-right_shift)) & 0xffff);
+
+      inout[i] = temp;
+
+      /* The shift may reduce ndigits */
+      if (i+1 == ndigits && temp == 0)
+         ndigits = i;
+   }
+
+   return ndigits;
+}
+
+static int
+uarb_cmp(uarb a, int adigits, uarb b, int bdigits)
+   /* Return -1/0/+1 according as a<b/a==b/a>b */
+{
+   if (adigits < bdigits)
+      return -1;
+
+   if (adigits > bdigits)
+      return 1;
+
+   while (adigits-- > 0)
+      if (a[adigits] < b[adigits])
+         return -1;
+
+      else if (a[adigits] > b[adigits])
+         return 1;
+
+   return 0;
+}
+
+#if 0 /*UNUSED*/
+static int
+uarb_eq32(uarb num, int digits, png_uint_32 val)
+   /* Return true if the uarb is equal to 'val' */
+{
+   switch (digits)
+   {
+      case 0:  return val == 0;
+      case 1:  return val == num[0];
+      case 2:  return (val & 0xffff) == num[0] && (val >> 16) == num[1];
+      default: return 0;
+   }
+}
+#endif
+
+static void
+uarb_printx(uarb num, int digits, FILE *out)
+   /* Print 'num' as a hexadecimal number (easier than decimal!) */
+{
+   while (digits > 0)
+      if (num[--digits] > 0)
+      {
+         fprintf(out, "0x%x", num[digits]);
+
+         while (digits > 0)
+            fprintf(out, "%.4x", num[--digits]);
+      }
+
+      else if (digits == 0) /* the number is 0 */
+         fputs("0x0", out);
+}
+
+static void
+uarb_print(uarb num, int digits, FILE *out)
+   /* Prints 'num' as a decimal if it will fit in an unsigned long, else as a
+    * hexadecimal number.  Notice that the results vary for images over 4GByte
+    * in a system dependent way, and the hexadecimal form doesn't work very well
+    * in awk script input.
+    *
+    *
+    * TODO: write uarb_div10
+    */
+{
+   if (digits * sizeof (udigit) > sizeof (unsigned long))
+      uarb_printx(num, digits, out);
+
+   else
+   {
+      unsigned long n = 0;
+
+      while (digits > 0)
+         n = (n << 16) + num[--digits];
+
+      fprintf(out, "%lu", n);
+   }
+}
+
+/* Generate random bytes.  This uses a boring repeatable algorithm and it
+ * is implemented here so that it gives the same set of numbers on every
+ * architecture.  It's a linear congruential generator (Knuth or Sedgewick
+ * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
+ * Hill, "The Art of Electronics" (Pseudo-Random Bit Sequences and Noise
+ * Generation.)
+ *
+ * (Copied from contrib/libtests/pngvalid.c)
+ */
+static void
+make_random_bytes(png_uint_32* seed, void* pv, size_t size)
+{
+   png_uint_32 u0 = seed[0], u1 = seed[1];
+   png_bytep bytes = voidcast(png_bytep, pv);
+
+   /* There are thirty-three bits; the next bit in the sequence is bit-33 XOR
+    * bit-20.  The top 1 bit is in u1, the bottom 32 are in u0.
+    */
+   size_t i;
+   for (i=0; i<size; ++i)
+   {
+      /* First generate 8 new bits then shift them in at the end. */
+      png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
+      u1 <<= 8;
+      u1 |= u0 >> 24;
+      u0 <<= 8;
+      u0 |= u;
+      *bytes++ = (png_byte)u;
+   }
+
+   seed[0] = u0;
+   seed[1] = u1;
+}
+
+/* Clear an object to a random value. */
+static void
+clear(void *pv, size_t size)
+{
+   static png_uint_32 clear_seed[2] = { 0x12345678, 0x9abcdef0 };
+   make_random_bytes(clear_seed, pv, size);
+}
+
+#define CLEAR(object) clear(&(object), sizeof (object))
+
+/* Copied from unreleased 1.7 code.
+ *
+ * CRC checking uses a local pre-built implementation of the Ethernet CRC32.
+ * This is to avoid a function call to the zlib DLL and to optimize the
+ * byte-by-byte case.
+ */
+static png_uint_32 crc_table[256] =
+{
+   0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
+   0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
+   0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
+   0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+   0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,
+   0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+   0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,
+   0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+   0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
+   0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,
+   0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
+   0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+   0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,
+   0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,
+   0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
+   0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+   0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,
+   0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+   0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,
+   0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+   0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
+   0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,
+   0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,
+   0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+   0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
+   0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,
+   0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
+   0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+   0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,
+   0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+   0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,
+   0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+   0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
+   0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,
+   0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,
+   0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+   0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,
+   0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,
+   0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
+   0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+   0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,
+   0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+   0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,
+   0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+   0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
+   0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
+   0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,
+   0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+   0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,
+   0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,
+   0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
+   0x2d02ef8d
+};
+
+/* The CRC calculated here *IS* conditioned, the corresponding value used by
+ * zlib and the result value is obtained by XORing with CRC_INIT, which is also
+ * the first value that must be passed in (for the first byte) to crc_one_byte.
+ */
+#define CRC_INIT 0xffffffff
+
+static png_uint_32
+crc_one_byte(png_uint_32 crc, int b)
+{
+   return crc_table[(crc ^ b) & 0xff] ^ (crc >> 8);
+}
+
+static png_uint_32
+crc_init_4(png_uint_32 value)
+{
+   /* This is an alternative to the algorithm used in zlib, which requires four
+    * separate tables to parallelize the four byte operations, it only works for
+    * a CRC of the first four bytes of the stream, but this is what happens in
+    * the parser below where length+chunk-name is read and chunk-name used to
+    * initialize the CRC.  Notice that the calculation here avoids repeated
+    * conditioning (xor with 0xffffffff) by storing the conditioned value.
+    */
+   png_uint_32 crc = crc_table[(~value >> 24)] ^ 0xffffff;
+
+   crc = crc_table[(crc ^ (value >> 16)) & 0xff] ^ (crc >> 8);
+   crc = crc_table[(crc ^ (value >> 8)) & 0xff] ^ (crc >> 8);
+   return crc_table[(crc ^ value) & 0xff] ^ (crc >> 8);
+}
+
+static int
+chunk_type_valid(png_uint_32 c)
+   /* Bit whacking approach to chunk name validation that is intended to avoid
+    * branches.  The cost is that it uses a lot of 32-bit constants, which might
+    * be bad on some architectures.
+    */
+{
+   png_uint_32 t;
+
+   /* Remove bit 5 from all but the reserved byte; this means every
+    * 8-bit unit must be in the range 65-90 to be valid.  So bit 5
+    * must be zero, bit 6 must be set and bit 7 zero.
+    */
+   c &= ~PNG_U32(32,32,0,32);
+   t = (c & ~0x1f1f1f1f) ^ 0x40404040;
+
+   /* Subtract 65 for each 8-bit quantity, this must not overflow
+    * and each byte must then be in the range 0-25.
+    */
+   c -= PNG_U32(65,65,65,65);
+   t |=c ;
+
+   /* Subtract 26, handling the overflow which should set the top
+    * three bits of each byte.
+    */
+   c -= PNG_U32(25,25,25,26);
+   t |= ~c;
+
+   return (t & 0xe0e0e0e0) == 0;
+}
+
+/**************************** CONTROL INFORMATION *****************************/
+
+/* Information about a sequence of IDAT chunks, the chunks have been re-synced
+ * using sync_stream below and the new lengths are recorded here.  Because the
+ * number of chunks is unlimited this is handled using a linked list of these
+ * structures.
+ */
+struct IDAT_list
+{
+   struct IDAT_list *next;     /* Linked list */
+   unsigned int      length;   /* Actual length of the array below */
+   unsigned int      count;    /* Number of entries that are valid */
+#     define IDAT_INIT_LENGTH 16
+   png_uint_32       lengths[IDAT_INIT_LENGTH];
+};
+
+static void
+IDAT_list_init(struct IDAT_list *list)
+{
+   CLEAR(*list);
+
+   list->next = NULL;
+   list->length = IDAT_INIT_LENGTH;
+}
+
+static size_t
+IDAT_list_size(struct IDAT_list *list, unsigned int length)
+   /* Return the size in bytes of an IDAT_list of the given length. */
+{
+   if (list != NULL)
+      length = list->length;
+
+   return sizeof *list - sizeof list->lengths +
+      length * sizeof list->lengths[0];
+}
+
+static void
+IDAT_list_end(struct IDAT_list *IDAT_list)
+{
+   struct IDAT_list *list = IDAT_list->next;
+
+   CLEAR(*IDAT_list);
+
+   while (list != NULL)
+   {
+      struct IDAT_list *next = list->next;
+
+      clear(list, IDAT_list_size(list, 0));
+      free(list);
+      list = next;
+   }
+}
+
+static struct IDAT_list *
+IDAT_list_extend(struct IDAT_list *tail)
+{
+   /* Use the previous cached value if available. */
+   struct IDAT_list *next = tail->next;
+
+   if (next == NULL)
+   {
+      /* Insert a new, malloc'ed, block of IDAT information buffers, this
+       * one twice as large as the previous one:
+       */
+      unsigned int length = 2 * tail->length;
+
+      if (length < tail->length) /* arithmetic overflow */
+         length = tail->length;
+
+      next = voidcast(IDAT_list*, malloc(IDAT_list_size(NULL, length)));
+      CLEAR(*next);
+
+      /* The caller must handle this: */
+      if (next == NULL)
+         return NULL;
+
+      next->next = NULL;
+      next->length = length;
+      tail->next = next;
+   }
+
+   return next;
+}
+
+/* GLOBAL CONTROL STRUCTURE */
+struct global
+{
+   /* PUBLIC GLOBAL VARIABLES: OWNER INITIALIZE */
+   unsigned int   errors        :1; /* print file errors to stderr */
+   unsigned int   warnings      :1; /* print libpng warnings to stderr */
+   unsigned int   optimize_zlib :1; /* Run optimization search */
+   unsigned int   quiet         :2; /* don't output summaries */
+   unsigned int   verbose       :3; /* various internal tracking */
+   unsigned int   skip          :3; /* Non-critical chunks to skip */
+#     define SKIP_NONE      0
+#     define SKIP_BAD_CRC   1    /* Chunks with a bad CRC */
+#     define SKIP_UNSAFE    2    /* Chunks not safe to copy */
+#     define SKIP_UNUSED    3    /* Chunks not used by libpng */
+#     define SKIP_TRANSFORM 4    /* Chunks only used in transforms */
+#     define SKIP_COLOR     5    /* Everything but tRNS, sBIT, gAMA and sRGB */
+#     define SKIP_ALL       6    /* Everything but tRNS and sBIT */
+
+   png_uint_32    idat_max;         /* 0 to perform no re-chunking */
+
+   int            status_code;      /* Accumulated status code */
+#     define TOO_FAR_BACK   0x01 /* found a too-far-back error */
+#     define CRC_ERROR      0x02 /* fixed an invalid CRC */
+#     define STREAM_ERROR   0x04 /* damaged PNG stream (may be fixable) */
+#     define TRUNCATED      0x08 /* truncated but still readable */
+#     define FILE_ERROR     0x10 /* could not read the file */
+#     define WRITE_ERROR    0x20 /* write error (this terminates the read) */
+#     define INTERNAL_ERROR 0x40 /* internal limits/errors encountered */
+
+   /* PUBLIC GLOBAL VARIABLES: USED INTERNALLY BY IDAT READ CODE */
+   struct IDAT_list idat_cache;  /* Cache of file IDAT information buffers */
+      /* The structure is shared across all uses of this global control
+       * structure to avoid reallocation between IDAT streams.
+       */
+};
+
+static int
+global_end(struct global *global)
+{
+
+   int rc;
+
+   IDAT_list_end(&global->idat_cache);
+   rc = global->status_code;
+   CLEAR(*global);
+   return rc;
+}
+
+static void
+global_init(struct global *global)
+   /* Call this once (and only once) to initialize the control */
+{
+   CLEAR(*global);
+
+   /* Globals */
+   global->errors        = 0;
+   global->warnings      = 0;
+   global->quiet         = 0;
+   global->verbose       = 0;
+   global->idat_max      = 0;         /* no re-chunking of IDAT */
+   global->optimize_zlib = 0;
+   global->skip          = SKIP_NONE;
+   global->status_code   = 0;
+
+   IDAT_list_init(&global->idat_cache);
+}
+
+static int
+skip_chunk_type(const struct global *global, png_uint_32 type)
+   /* Return true if this chunk is to be skipped according to the --strip
+    * option.  This code needs to recognize all known ancillary chunks in order
+    * to handle the --strip=unsafe option.
+    */
+{
+   /* Never strip critical chunks: */
+   if (CRITICAL(type))
+      return 0;
+
+   switch (type)
+   {
+      /* Chunks that are treated as, effectively, critical because they affect
+       * correct interpretation of the pixel values:
+       */
+      case png_tRNS: case png_sBIT:
+         return 0;
+
+      /* Chunks that specify gamma encoding which should therefore only be
+       * removed if the user insists:
+       */
+      case png_gAMA: case png_sRGB:
+         if (global->skip >= SKIP_ALL)
+            return 1;
+         return 0;
+
+      /* Chunks that affect color interpretation - not used by libpng and rarely
+       * used by applications, but technically still required for correct
+       * interpretation of the image data:
+       */
+      case png_cHRM: case png_iCCP:
+         if (global->skip >= SKIP_COLOR)
+            return 1;
+         return 0;
+
+      /* Other chunks that are used by libpng in image transformations (as
+       * opposed to known chunks that have get/set APIs but are not otherwise
+       * used.)
+       */
+      case png_bKGD:
+         if (global->skip >= SKIP_TRANSFORM)
+            return 1;
+         return 0;
+
+      /* All other chunks that libpng knows about and affect neither image
+       * interpretation nor libpng transforms - chunks that are effectively
+       * unused by libpng even though libpng might recognize and store them.
+       */
+      case png_fRAc: case png_gIFg: case png_gIFt: case png_gIFx: case png_hIST:
+      case png_iTXt: case png_oFFs: case png_pCAL: case png_pHYs: case png_sCAL:
+      case png_sPLT: case png_sTER: case png_tEXt: case png_tIME: case png_zTXt:
+         if (global->skip >= SKIP_UNUSED)
+            return 1;
+         return 0;
+
+      /* Chunks that libpng does not know about (notice that this depends on the
+       * list above including all known chunks!)  The decision here depends on
+       * whether the safe-to-copy bit is set in the chunk type.
+       */
+      default:
+         if (SAFE_TO_COPY(type))
+         {
+            if (global->skip >= SKIP_UNUSED) /* as above */
+               return 1;
+         }
+
+         else if (global->skip >= SKIP_UNSAFE)
+            return 1;
+
+         return 0;
+   }
+}
+
+/* PER-FILE CONTROL STRUCTURE */
+struct chunk;
+struct IDAT;
+struct file
+{
+   /* ANCESTORS */
+   struct global *global;
+
+   /* PUBLIC PER-FILE VARIABLES: CALLER INITIALIZE */
+   const char *   file_name;
+   const char *   out_name;      /* Name of output file (if required) */
+
+   /* PUBLIC PER-FILE VARIABLES: SET BY PNG READ CODE */
+   /* File specific result codes */
+   int            status_code;   /* Set to a bit mask of the following: */
+   int            read_errno;    /* Records a read error errno */
+   int            write_errno;   /* Records a write error errno */
+
+   /* IHDR information */
+   png_uint_32    width;
+   png_uint_32    height;
+   png_byte       bit_depth;
+   png_byte       color_type;
+   png_byte       compression_method;
+   png_byte       filter_method;
+   png_byte       interlace_method;
+
+   udigit         image_bytes[5];
+   int            image_digits;
+
+   /* PROTECTED PER-FILE VARIABLES: USED BY THE READ CODE */
+   FILE *         file;          /* Original PNG file */
+   FILE *         out;           /* If a new one is being written */
+   jmp_buf        jmpbuf;        /* Set while reading a PNG */
+
+   /* PROTECTED CHUNK SPECIFIC VARIABLES: USED BY CHUNK CODE */
+   /* The following variables are used during reading to record the length, type
+    * and data position of the *next* chunk or, right at the start, the
+    * signature (in length,type).
+    *
+    * When a chunk control structure is instantiated these values are copied
+    * into the structure and can then be overwritten with the data for the next
+    * chunk.
+    */
+   fpos_t         data_pos;      /* Position of first byte of chunk data */
+   png_uint_32    length;        /* First word (length or signature start) */
+   png_uint_32    type;          /* Second word (type or signature end) */
+   png_uint_32    crc;           /* Running chunk CRC (used by read_chunk) */
+
+   /* These counts are maintained by the read and write routines below and are
+    * reset by the chunk handling code.  They record the total number of bytes
+    * read or written for the chunk, including the header (length,type) bytes.
+    */
+   png_uint_32    read_count;    /* Count of bytes read (in the chunk) */
+   png_uint_32    write_count;   /* Count of bytes written (in the chunk) */
+   int            state;         /* As defined here: */
+#     define STATE_SIGNATURE  0  /* The signature is being written */
+#     define STATE_CHUNKS     1  /* Non-IDAT chunks are being written */
+#     define STATE_IDAT       2  /* An IDAT stream is being written */
+
+   /* Two pointers used to enable clean-up in the event of fatal errors and to
+    * hold state about the parser process (only one of each at present.)
+    */
+   struct chunk * chunk;
+   struct IDAT *  idat;
+
+   /* Interface to allocate a new chunk or IDAT control structure.  The result
+    * is returned by setting one or other of the above variables.  Note that the
+    * relevant initializer is called by the allocator function.  The alloc_ptr
+    * is used only by the implementation of the allocate function.
+    */
+   void *         alloc_ptr;
+   void         (*alloc)(struct file*,int idat);
+                                  /* idat: allocate IDAT not chunk */
+};
+
+/* Valid longjmp (stop) codes are: */
+#define LIBPNG_WARNING_CODE   1 /* generic png_error */
+#define LIBPNG_ERROR_CODE     2 /* generic png_error */
+#define ZLIB_ERROR_CODE       3 /* generic zlib error */
+#define INVALID_ERROR_CODE    4 /* detected an invalid PNG */
+#define READ_ERROR_CODE       5 /* read failed */
+#define WRITE_ERROR_CODE      6 /* error in write */
+#define UNEXPECTED_ERROR_CODE 7 /* unexpected (internal?) error */
+
+static void
+emit_string(const char *str, FILE *out)
+   /* Print a string with spaces replaced by '_' and non-printing characters by
+    * an octal escape.
+    */
+{
+   for (; *str; ++str)
+      if (isgraph(UCHAR_MAX & *str))
+         putc(*str, out);
+
+      else if (isspace(UCHAR_MAX & *str))
+         putc('_', out);
+
+      else
+         fprintf(out, "\\%.3o", *str);
+}
+
+static const char *
+strcode(int code)
+{
+   switch (code)
+   {
+      case LIBPNG_WARNING_CODE:   return "warning";
+      case LIBPNG_ERROR_CODE:     return "libpng";
+      case ZLIB_ERROR_CODE:       return "zlib";
+      case INVALID_ERROR_CODE:    return "invalid";
+      case READ_ERROR_CODE:       return "read";
+      case WRITE_ERROR_CODE:      return "write";
+      case UNEXPECTED_ERROR_CODE: return "unexpected";
+      default:                    return "INVALID";
+   }
+}
+
+static void
+emit_error(struct file *file, int code, const char *what)
+   /* Generic error message routine, takes a 'stop' code but can be used
+    * elsewhere.  Always outputs a message.
+    */
+{
+   const char *reason;
+   int err = 0;
+
+   switch (code)
+   {
+      case LIBPNG_WARNING_CODE:   reason = "libpng warning:"; break;
+      case LIBPNG_ERROR_CODE:     reason = "libpng error:"; break;
+      case ZLIB_ERROR_CODE:       reason = "zlib error:"; break;
+      case INVALID_ERROR_CODE:    reason = "invalid"; break;
+      case READ_ERROR_CODE:       reason = "read failure:";
+                                  err = file->read_errno;
+                                  break;
+      case WRITE_ERROR_CODE:      reason = "write error";
+                                  err = file->write_errno;
+                                  break;
+      case UNEXPECTED_ERROR_CODE: reason = "unexpected error:";
+                                  err = file->read_errno;
+                                  if (err == 0)
+                                     err = file->write_errno;
+                                  break;
+      default:                    reason = "INVALID (internal error):"; break;
+   }
+
+   if (err != 0)
+      fprintf(stderr, "%s: %s %s [%s]\n", file->file_name, reason, what,
+         strerror(err));
+
+   else
+      fprintf(stderr, "%s: %s %s\n", file->file_name, reason, what);
+}
+
+static void chunk_end(struct chunk **);
+static void IDAT_end(struct IDAT **);
+
+static int
+file_end(struct file *file)
+{
+   int rc;
+
+   /* If either of the chunk pointers are set end them here, the IDAT structure
+    * must be deallocated first as it may deallocate the chunk structure.
+    */
+   if (file->idat != NULL)
+      IDAT_end(&file->idat);
+
+   if (file->chunk != NULL)
+      chunk_end(&file->chunk);
+
+   rc = file->status_code;
+
+   if (file->file != NULL)
+      (void)fclose(file->file);
+
+   if (file->out != NULL)
+   {
+      /* On some systems 'fclose' deletes the FILE struct (making it
+       * inaccessbile).  There is no guarantee that fclose returns an error
+       * code from fflush or, indeed, from the FILE error indicator.  There is
+       * also no explicit (or clear) guarantee in the standard that anything
+       * other than a read or write operation sets the error indicator; fflush
+       * is not a read or write operation, so both conditions must be checked
+       * to ensure the close succeeded and in ANSI-C conformant code they must
+       * be checked before the fclose call.
+       */
+      const int err = fflush(file->out) || ferror(file->out);
+
+      if (fclose(file->out) || err)
+      {
+         perror(file->out_name);
+         emit_error(file, READ_ERROR_CODE, "output write error");
+         rc |= WRITE_ERROR;
+      }
+   }
+
+   /* Accumulate the result codes */
+   file->global->status_code |= rc;
+
+   CLEAR(*file);
+
+   return rc; /* status code: non-zero on read or write error */
+}
+
+static int
+file_init(struct file *file, struct global *global, const char *file_name,
+   const char *out_name, void *alloc_ptr, void (*alloc)(struct file*,int))
+   /* Initialize a file control structure.  This will open the given files as
+    * well.  The status code returned is 0 on success, non zero (using the flags
+    * above) on a file open error.
+    */
+{
+   CLEAR(*file);
+   file->global = global;
+
+   file->file_name = file_name;
+   file->out_name = out_name;
+   file->status_code = 0;
+   file->read_errno = 0;
+   file->write_errno = 0;
+
+   file->file = NULL;
+   file->out = NULL;
+   /* jmpbuf is garbage: must be set by read_png */
+
+   file->read_count = 0;
+   file->state = STATE_SIGNATURE;
+
+   file->chunk = NULL;
+   file->idat = NULL;
+
+   file->alloc_ptr = alloc_ptr;
+   file->alloc = alloc;
+
+   /* Open the files: */
+   assert(file_name != NULL);
+   file->file = fopen(file_name, "rb");
+
+   if (file->file == NULL)
+   {
+      file->read_errno = errno;
+      file->status_code |= FILE_ERROR;
+      /* Always output: please give a readable file! */
+      perror(file_name);
+      return FILE_ERROR;
+   }
+
+   if (out_name != NULL)
+   {
+      file->out = fopen(out_name, "wb");
+
+      if (file->out == NULL)
+      {
+         file->write_errno = errno;
+         file->status_code |= WRITE_ERROR;
+         perror(out_name);
+         return WRITE_ERROR;
+      }
+   }
+
+   return 0;
+}
+
+static void
+log_error(struct file *file, int code, const char *what)
+   /* Like emit_error but checks the global 'errors' flag */
+{
+   if (file->global->errors)
+      emit_error(file, code, what);
+}
+
+static char
+type_char(png_uint_32 v)
+{
+   /* In fact because chunk::chunk_type is validated prior to any call to this
+    * function it will always return a-zA-Z, but the extra codes are just there
+    * to help in finding internal (programming) errors.  Note that the code only
+    * ever considers the low 7 bits of the value (so it is not necessary for the
+    * type_name function to mask of the byte.)
+    */
+   if (v & 32)
+      return "!abcdefghijklmnopqrstuvwxyz56789"[(v-96)&31];
+
+   else
+      return "@ABCDEFGHIJKLMNOPQRSTUVWXYZ01234"[(v-64)&31];
+}
+
+static void
+type_name(png_uint_32 type, FILE *out)
+{
+   putc(type_char(type >> 24), out);
+   putc(type_char(type >> 16), out);
+   putc(type_char(type >>  8), out);
+   putc(type_char(type      ), out);
+}
+
+static void
+type_sep(FILE *out)
+{
+   putc(':', out);
+   putc(' ', out);
+}
+
+static png_uint_32 current_type(struct file *file, int code);
+
+PNG_NORETURN static void
+stop(struct file *file, int code, const char *what)
+   /* Return control when a PNG file cannot be read. This outputs an 'ERR'
+    * summary line too.
+    */
+{
+   log_error(file, code, what);
+
+   /* The chunk being read is typically identified by file->chunk or, if this is
+    * NULL, by file->type.  This may be wrong if libpng reads ahead, but this
+    * only happens with IDAT where libpng reads the header then jumps around
+    * finding errors in the previous chunks.  We know that is happening because
+    * we are at the start of the IDAT (i.e. no IDAT data has yet been written.)
+    *
+    * SUMMARY FORMAT (stop):
+    *
+    * IDAT ERR status code read-errno write-errno message file
+    *
+    * 'uncompressed' will be 0 if there was a problem in the IHDR.  The errno
+    * values are emit_string(strerror(errno)).
+    */
+   if (file->global->quiet < 2) /* need two quiets to stop this. */
+   {
+      png_uint_32 type;
+
+      if (file->chunk != NULL)
+         type = current_type(file, code); /* Gropes in struct chunk and IDAT */
+
+      else
+         type = file->type;
+
+      if (type)
+         type_name(type, stdout);
+
+      else /* magic: an IDAT header, produces bogons for too many IDATs */
+         fputs("HEAD", stdout); /* not a registered chunk! */
+
+      printf(" ERR %.2x %s ", file->status_code, strcode(code));
+      /* This only works one strerror at a time, because of the way strerror is
+       * implemented.
+       */
+      emit_string(strerror(file->read_errno), stdout);
+      putc(' ', stdout);
+      emit_string(strerror(file->write_errno), stdout);
+      putc(' ', stdout);
+      emit_string(what, stdout);
+      putc(' ', stdout);
+      fputs(file->file_name, stdout);
+      putc('\n', stdout);
+   }
+
+   file->status_code |= FILE_ERROR;
+   longjmp(file->jmpbuf, code);
+}
+
+PNG_NORETURN static void
+stop_invalid(struct file *file, const char *what)
+{
+   stop(file, INVALID_ERROR_CODE, what);
+}
+
+static void
+type_message(struct file *file, png_uint_32 type, const char *what)
+   /* Error message for a chunk; the chunk name comes from 'type' */
+{
+   if (file->global->errors)
+   {
+      fputs(file->file_name, stderr);
+      type_sep(stderr);
+      type_name(type, stderr);
+      type_sep(stderr);
+      fputs(what, stderr);
+      putc('\n', stderr);
+   }
+}
+
+/* Input file positioning - we jump around in the input file while reading
+ * stuff, these wrappers deal with the error handling.
+ */
+static void
+file_getpos(struct file *file, fpos_t *pos)
+{
+   if (fgetpos(file->file, pos))
+   {
+      /* This is unexpected, so perror it */
+      perror(file->file_name);
+      stop(file, READ_ERROR_CODE, "fgetpos");
+   }
+}
+
+static void
+file_setpos(struct file *file, const fpos_t *pos)
+{
+   if (fsetpos(file->file, pos))
+   {
+      perror(file->file_name);
+      stop(file, READ_ERROR_CODE, "fsetpos");
+   }
+}
+
+static void
+getpos(struct file *file)
+   /* Get the current position and store it in 'data_pos'.  The corresponding
+    * setpos() function is chunk specific because it uses the copy of the
+    * position for the specific chunk.
+    */
+{
+   file_getpos(file, &file->data_pos);
+}
+
+
+/* Read utility - read a single byte, returns a value in the range 0..255 or EOF
+ * on a read error.  In the latter case status_code and read_errno are updated
+ * appropriately.
+ */
+static int
+read_byte(struct file *file)
+{
+   int ch = getc(file->file);
+
+   if (ch >= 0 && ch <= 255)
+   {
+      ++(file->read_count);
+      return ch;
+   }
+
+   else if (ch != EOF)
+   {
+      file->status_code |= INTERNAL_ERROR;
+      file->read_errno = ERANGE; /* out of range character */
+
+      /* This is very unexpected; an error message is always output: */
+      emit_error(file, UNEXPECTED_ERROR_CODE, "file read");
+   }
+
+#  ifdef EINTR
+      else if (errno == EINTR) /* Interrupted, try again */
+      {
+         errno = 0;
+         return read_byte(file);
+      }
+#  endif
+
+   else
+   {
+      /* An error, it doesn't really matter what the error is but it gets
+       * recorded anyway.
+       */
+      if (ferror(file->file))
+         file->read_errno = errno;
+
+      else if (feof(file->file))
+         file->read_errno = 0; /* I.e. a regular EOF, no error */
+
+      else /* unexpected */
+         file->read_errno = EDOM;
+   }
+
+   /* 'TRUNCATED' is used for all cases of failure to read a byte, because of
+    * the way libpng works a byte read is never attempted unless the byte is
+    * expected to be there, so EOF should not occur.
+    */
+   file->status_code |= TRUNCATED;
+   return EOF;
+}
+
+static png_byte
+reread_byte(struct file *file)
+   /* Read a byte when an error is not expected to happen because the byte has
+    * been read before without error.
+    */
+{
+   int ch = getc(file->file);
+
+   if (errno != 0)
+      file->read_errno = errno;
+
+   if (ch < 0 || ch > 255)
+      stop(file, UNEXPECTED_ERROR_CODE, "reread");
+
+   return (png_byte)ch;
+}
+
+static png_uint_32
+reread_4(struct file *file)
+   /* The same but for a four byte quantity */
+{
+   png_uint_32 result = 0;
+   int i = 0;
+
+   while (++i <= 4)
+      result = (result << 8) + reread_byte(file);
+
+   return result;
+}
+
+static void
+skip_12(struct file *file)
+   /* Skip exactly 12 bytes in the input stream - used to skip a CRC and chunk
+    * header that has been read before.
+    */
+{
+   /* Since the chunks were read before this shouldn't fail: */
+   if (fseek(file->file, 12, SEEK_CUR) != 0)
+   {
+      if (errno != 0)
+         file->read_errno = errno;
+
+      stop(file, UNEXPECTED_ERROR_CODE, "reskip");
+   }
+}
+
+static void
+write_byte(struct file *file, int b)
+   /* Write one byte to the output - this causes a fatal error if the write
+    * fails and the read of this PNG file immediately terminates.  Just
+    * increments the write count if there is no output file.
+    */
+{
+   if (file->out != NULL)
+   {
+      if (putc(b, file->out) != b)
+      {
+         file->write_errno = errno;
+         file->status_code |= WRITE_ERROR;
+         stop(file, WRITE_ERROR_CODE, "write byte");
+      }
+   }
+
+   ++(file->write_count);
+}
+
+/* Derivatives of the read/write functions. */
+static unsigned int
+read_4(struct file *file, png_uint_32 *pu)
+   /* Read four bytes, returns the number of bytes read successfully and, if all
+    * four bytes are read, assigns the result to *pu.
+    */
+{
+   unsigned int i = 0;
+   png_uint_32 val = 0;
+
+   do
+   {
+      int ch = read_byte(file);
+
+      if (ch == EOF)
+         return i;
+
+      val = (val << 8) + ch;
+   } while (++i < 4);
+
+   *pu = val;
+   return i;
+}
+
+/* CRC handling - read but calculate the CRC while doing so. */
+static int
+crc_read_many(struct file *file, png_uint_32 length)
+   /* Reads 'length' bytes and updates the CRC, returns true on success, false
+    * if the input is truncated.
+    */
+{
+   if (length > 0)
+   {
+      png_uint_32 crc = file->crc;
+
+      do
+      {
+         int ch = read_byte(file);
+
+         if (ch == EOF)
+            return 0; /* Truncated */
+
+         crc = crc_one_byte(crc, ch);
+      }
+      while (--length > 0);
+
+      file->crc = crc;
+   }
+
+   return 1; /* OK */
+}
+
+static int
+calc_image_size(struct file *file)
+   /* Fill in the image_bytes field given the IHDR information, calls stop on
+    * error.
+    */
+{
+   png_uint_16 pd = file->bit_depth;
+
+   switch (file->color_type)
+   {
+      default:
+         stop_invalid(file, "IHDR: colour type");
+
+      invalid_bit_depth:
+         stop_invalid(file, "IHDR: bit depth");
+
+      case 0: /* g */
+         if (pd != 1 && pd != 2 && pd != 4 && pd != 8 && pd != 16)
+            goto invalid_bit_depth;
+         break;
+
+      case 3:
+         if (pd != 1 && pd != 2 && pd != 4 && pd != 8)
+            goto invalid_bit_depth;
+         break;
+
+      case 2: /* rgb */
+         if (pd != 8 && pd != 16)
+            goto invalid_bit_depth;
+
+         pd = (png_uint_16)(pd * 3);
+         break;
+
+      case 4: /* ga */
+         if (pd != 8 && pd != 16)
+            goto invalid_bit_depth;
+
+         pd = (png_uint_16)(pd * 2);
+         break;
+
+      case 6: /* rgba */
+         if (pd != 8 && pd != 16)
+            goto invalid_bit_depth;
+
+         pd = (png_uint_16)(pd * 4);
+         break;
+   }
+
+   if (file->width < 1 || file->width > 0x7fffffff)
+      stop_invalid(file, "IHDR: width");
+
+   else if (file->height < 1 || file->height > 0x7fffffff)
+      stop_invalid(file, "IHDR: height");
+
+   else if (file->compression_method != 0)
+      stop_invalid(file, "IHDR: compression method");
+
+   else if (file->filter_method != 0)
+      stop_invalid(file, "IHDR: filter method");
+
+   else switch (file->interlace_method)
+   {
+      case PNG_INTERLACE_ADAM7:
+         /* Interlacing makes the image larger because of the replication of
+          * both the filter byte and the padding to a byte boundary.
+          */
+         {
+            int pass;
+            int image_digits = 0;
+            udigit row_width[2], row_bytes[3];
+
+            for (pass=0; pass<=6; ++pass)
+            {
+               png_uint_32 pw = PNG_PASS_COLS(file->width, pass);
+
+               if (pw > 0)
+               {
+                  int  digits;
+
+                  /* calculate 1+((pw*pd+7)>>3) in row_bytes */
+                  digits = uarb_mult_digit(row_bytes, uarb_set(row_bytes, 7),
+                     row_width, uarb_set(row_width, pw), pd);
+                  digits = uarb_shift(row_bytes, digits, 3);
+                  digits = uarb_inc(row_bytes, digits, 1);
+
+                  /* Add row_bytes * pass-height to the file image_bytes field
+                   */
+                  image_digits = uarb_mult32(file->image_bytes, image_digits,
+                     row_bytes, digits,
+                     PNG_PASS_ROWS(file->height, pass));
+               }
+            }
+
+            file->image_digits = image_digits;
+         }
+         break;
+
+      case PNG_INTERLACE_NONE:
+         {
+            int  digits;
+            udigit row_width[2], row_bytes[3];
+
+            /* As above, but use image_width in place of the pass width: */
+            digits = uarb_mult_digit(row_bytes, uarb_set(row_bytes, 7),
+               row_width, uarb_set(row_width, file->width), pd);
+            digits = uarb_shift(row_bytes, digits, 3);
+            digits = uarb_inc(row_bytes, digits, 1);
+
+            /* Set row_bytes * image-height to the file image_bytes field */
+            file->image_digits = uarb_mult32(file->image_bytes, 0,
+               row_bytes, digits, file->height);
+         }
+         break;
+
+      default:
+         stop_invalid(file, "IHDR: interlace method");
+   }
+
+   assert(file->image_digits >= 1 && file->image_digits <= 5);
+   return 1;
+}
+
+/* PER-CHUNK CONTROL STRUCTURE
+ * This structure is instantiated for each chunk, except for the IDAT chunks
+ * where one chunk control structure is used for the whole of a single stream of
+ * IDAT chunks (see the IDAT control structure below).
+ */
+struct chunk
+{
+   /* ANCESTORS */
+   struct file *         file;
+   struct global *       global;
+
+   /* PUBLIC IDAT INFORMATION: SET BY THE ZLIB CODE */
+   udigit         uncompressed_bytes[5];
+   int            uncompressed_digits;
+   udigit         compressed_bytes[5];
+   int            compressed_digits;
+
+   /* PUBLIC PER-CHUNK INFORMATION: USED BY CHUNK READ CODE */
+   /* This information is filled in by chunk_init from the data in the file
+    * control structure, but chunk_length may be changed later.
+    */
+   fpos_t         chunk_data_pos;    /* Position of first byte of chunk data */
+   png_uint_32    chunk_length;      /* From header (or modified below) */
+   png_uint_32    chunk_type;        /* From header */
+
+   /* PUBLIC PER-CHUNK INFORMATION: FOR THE CHUNK WRITE CODE */
+   png_uint_32    write_crc;         /* Output CRC (may differ from read_crc) */
+   png_uint_32    rewrite_offset;    /* Count of bytes before rewrite. */
+   int            rewrite_length;    /* Number of bytes left to change */
+   png_byte       rewrite_buffer[2]; /* Buffer of new byte values */
+};
+
+static void
+chunk_message(struct chunk *chunk, const char *message)
+{
+   type_message(chunk->file, chunk->chunk_type, message);
+}
+
+static void
+chunk_end(struct chunk **chunk_var)
+{
+   struct chunk *chunk = *chunk_var;
+
+   *chunk_var = NULL;
+   CLEAR(*chunk);
+}
+
+static void
+chunk_init(struct chunk * const chunk, struct file * const file)
+   /* When a chunk is initialized the file length/type/pos are copied into the
+    * corresponding chunk fields and the new chunk is registered in the file
+    * structure.  There can only be one chunk at a time.
+    *
+    * NOTE: this routine must onely be called from the file alloc routine!
+    */
+{
+   assert(file->chunk == NULL);
+
+   CLEAR(*chunk);
+
+   chunk->file = file;
+   chunk->global = file->global;
+
+   chunk->chunk_data_pos = file->data_pos;
+   chunk->chunk_length = file->length;
+   chunk->chunk_type = file->type;
+
+   /* Compressed/uncompressed size information (from the zlib control structure
+    * that is used to check the compressed data in a chunk.)
+    */
+   chunk->uncompressed_digits = 0;
+   chunk->compressed_digits = 0;
+
+   file->chunk = chunk;
+}
+
+static png_uint_32
+current_type(struct file *file, int code)
+   /* Guess the actual chunk type that causes a stop() */
+{
+   /* This may return png_IDAT for errors detected (late) in the header; that
+    * includes any inter-chunk consistency check that libpng performs.  Assume
+    * that if the chunk_type is png_IDAT and the file write count is 8 this is
+    * what is happening.
+    */
+   if (file->chunk != NULL)
+   {
+      png_uint_32 type = file->chunk->chunk_type;
+
+      /* This is probably wrong for the excess IDATs case, because then libpng
+       * whines about too many of them (apparently in some cases erroneously)
+       * when the header is read.
+       */
+      if (code <= LIBPNG_ERROR_CODE && type == png_IDAT &&
+         file->write_count == 8)
+         type = 0; /* magic */
+
+      return type;
+   }
+
+   else
+      return file->type;
+}
+
+static void
+setpos(struct chunk *chunk)
+   /* Reset the position to 'chunk_data_pos' - the start of the data for this
+    * chunk.  As a side effect the read_count in the file is reset to 8, just
+    * after the length/type header.
+    */
+{
+   chunk->file->read_count = 8;
+   file_setpos(chunk->file, &chunk->chunk_data_pos);
+}
+
+/* Specific chunk handling - called for each chunk header, all special chunk
+ * processing is initiated in these functions.
+ */
+/* The next functions handle special processing for those chunks with LZ data,
+ * the data is identified and checked for validity.  If there are problems which
+ * cannot be corrected the routines return false, otherwise true (although
+ * modification to the zlib header may be required.)
+ *
+ * The compressed data is in zlib format (RFC1950) and consequently has a
+ * minimum length of 7 bytes.
+ */
+static int zlib_check(struct file *file, png_uint_32 offset);
+
+static int
+process_zTXt_iCCP(struct file *file)
+   /* zTXt and iCCP have exactly the same form - keyword, null, compression
+    * method then compressed data.
+    */
+{
+   struct chunk *chunk = file->chunk;
+   png_uint_32 length;
+   png_uint_32 index = 0;
+
+   assert(chunk != NULL && file->idat == NULL);
+   length = chunk->chunk_length;
+   setpos(chunk);
+
+   while (length >= 9)
+   {
+      --length;
+      ++index;
+      if (reread_byte(file) == 0) /* keyword null terminator */
+      {
+         --length;
+         ++index;
+         (void)reread_byte(file); /* compression method */
+         return zlib_check(file, index);
+      }
+   }
+
+   chunk_message(chunk, "too short");
+   return 0; /* skip */
+}
+
+static int
+process_iTXt(struct file *file)
+{
+   /* Like zTXt but more fields. */
+   struct chunk *chunk = file->chunk;
+   png_uint_32 length;
+   png_uint_32 index = 0;
+
+   assert(chunk != NULL && file->idat == NULL);
+   length = chunk->chunk_length;
+   setpos(chunk);
+
+   while (length >= 5)
+   {
+      --length;
+      ++index;
+      if (reread_byte(file) == 0) /* keyword null terminator */
+      {
+         --length;
+         ++index;
+         if (reread_byte(file) == 0) /* uncompressed text */
+            return 1; /* nothing to check */
+
+         --length;
+         ++index;
+         (void)reread_byte(file); /* compression method */
+
+         /* Skip the language tag (null terminated). */
+         while (length >= 9)
+         {
+            --length;
+            ++index;
+            if (reread_byte(file) == 0) /* terminator */
+            {
+               /* Skip the translated keyword */
+               while (length >= 8)
+               {
+                  --length;
+                  ++index;
+                  if (reread_byte(file) == 0) /* terminator */
+                     return zlib_check(file, index);
+               }
+            }
+         }
+
+         /* Ran out of bytes in the compressed case. */
+         break;
+      }
+   }
+
+   log_error(file, INVALID_ERROR_CODE, "iTXt chunk length");
+
+   return 0; /* skip */
+}
+
+/* IDAT READ/WRITE CONTROL STRUCTURE */
+struct IDAT
+{
+   /* ANCESTORS */
+   struct file *         file;
+   struct global *       global;
+
+   /* PROTECTED IDAT INFORMATION: SET BY THE IDAT READ CODE */
+   struct IDAT_list *idat_list_head; /* START of the list of IDAT information */
+   struct IDAT_list *idat_list_tail; /* *END* of the list of IDAT information */
+
+   /* PROTECTED IDAT INFORMATION: USED BY THE IDAT WRITE CODE */
+   struct IDAT_list *idat_cur;       /* Current list entry */
+   unsigned int      idat_count;     /* And the *current* index into the list */
+   png_uint_32       idat_index;     /* Index of *next* input byte to write */
+   png_uint_32       idat_length;    /* Cache of current chunk length */
+};
+
+/* NOTE: there is currently no IDAT_reset, so a stream cannot contain more than
+ * one IDAT sequence (i.e. MNG is not supported).
+ */
+
+static void
+IDAT_end(struct IDAT **idat_var)
+{
+   struct IDAT *idat = *idat_var;
+   struct file *file = idat->file;
+
+   *idat_var = NULL;
+
+   CLEAR(*idat);
+
+   assert(file->chunk != NULL);
+   chunk_end(&file->chunk);
+
+   /* Regardless of why the IDAT was killed set the state back to CHUNKS (it may
+    * already be CHUNKS because the state isn't changed until process_IDAT
+    * returns; a stop will cause IDAT_end to be entered in state CHUNKS!)
+    */
+   file->state = STATE_CHUNKS;
+}
+
+static void
+IDAT_init(struct IDAT * const idat, struct file * const file)
+   /* When the chunk is png_IDAT instantiate an IDAT control structure in place
+    * of a chunk control structure.  The IDAT will instantiate a chunk control
+    * structure using the file alloc routine.
+    *
+    * NOTE: this routine must only be called from the file alloc routine!
+    */
+{
+   assert(file->chunk == NULL);
+   assert(file->idat == NULL);
+
+   CLEAR(*idat);
+
+   idat->file = file;
+   idat->global = file->global;
+
+   /* Initialize the tail to the pre-allocated buffer and set the count to 0
+    * (empty.)
+    */
+   idat->global->idat_cache.count = 0;
+   idat->idat_list_head = idat->idat_list_tail = &idat->global->idat_cache;
+
+   /* Now the chunk.  The allocator calls the initializer of the new chunk and
+    * stores the result in file->chunk:
+    */
+   file->alloc(file, 0/*chunk*/);
+   assert(file->chunk != NULL);
+
+   /* And store this for cleanup (and to check for double alloc or failure to
+    * free.)
+    */
+   file->idat = idat;
+}
+
+static png_uint_32
+rechunk_length(struct IDAT *idat, int start)
+   /* Return the length for the next IDAT chunk, taking into account
+    * rechunking.
+    */
+{
+   png_uint_32 len = idat->global->idat_max;
+
+   if (len == 0) /* use original chunk lengths */
+   {
+      const struct IDAT_list *cur;
+      unsigned int count;
+
+      if (start)
+         return idat->idat_length; /* use the cache */
+
+      /* Otherwise rechunk_length is called at the end of a chunk for the length
+       * of the next one.
+       */
+      cur = idat->idat_cur;
+      count = idat->idat_count;
+
+      assert(idat->idat_index == idat->idat_length &&
+         idat->idat_length == cur->lengths[count]);
+
+      /* Return length of the *next* chunk */
+      if (++count < cur->count)
+         return cur->lengths[count];
+
+      /* End of this list */
+      assert(cur != idat->idat_list_tail);
+      cur = cur->next;
+      assert(cur != NULL && cur->count > 0);
+      return cur->lengths[0];
+   }
+
+   else /* rechunking */
+   {
+      /* The chunk size is the lesser of file->idat_max and the number
+       * of remaining bytes.
+       */
+      png_uint_32 have = idat->idat_length - idat->idat_index;
+
+      if (len > have)
+      {
+         struct IDAT_list *cur = idat->idat_cur;
+         unsigned int j = idat->idat_count+1; /* the next IDAT in the list */
+
+         do
+         {
+            /* Add up the remaining bytes.  This can't overflow because the
+             * individual lengths are always <= 0x7fffffff, so when we add two
+             * of them overflow is not possible.
+             */
+            assert(cur != NULL);
+
+            for (;;)
+            {
+               /* NOTE: IDAT_list::count here, not IDAT_list::length */
+               for (; j < cur->count; ++j)
+               {
+                  have += cur->lengths[j];
+                  if (len <= have)
+                     return len;
+               }
+
+               /* If this was the end return the count of the available bytes */
+               if (cur == idat->idat_list_tail)
+                  return have;
+
+               cur = cur->next;
+               j = 0;
+            }
+         }
+         while (len > have);
+      }
+
+      return len;
+   }
+}
+
+static int
+process_IDAT(struct file *file)
+   /* Process the IDAT stream, this is the more complex than the preceding
+    * cases because the compressed data is spread across multiple IDAT chunks
+    * (typically).  Rechunking of the data is not handled here; all this
+    * function does is establish whether the zlib header needs to be modified.
+    *
+    * Initially the function returns false, indicating that the chunk should not
+    * be written.  It does this until the last IDAT chunk is passed in, then it
+    * checks the zlib data and returns true.
+    *
+    * It does not return false on a fatal error; it calls stop instead.
+    *
+    * The caller must have an instantiated (IDAT) control structure and it must
+    * have extent over the whole read of the IDAT stream.  For a PNG this means
+    * the whole PNG read, for MNG it could have lesser extent.
+    */
+{
+   struct IDAT_list *list;
+
+   assert(file->idat != NULL && file->chunk != NULL);
+
+   /* We need to first check the entire sequence of IDAT chunks to ensure the
+    * stream is in sync.  Do this by building a list of all the chunks and
+    * recording the length of each because the length may have been fixed up by
+    * sync_stream below.
+    *
+    * At the end of the list of chunks, where the type of the next chunk is not
+    * png_IDAT, process the whole stream using the list data to check validity
+    * then return control to the start and rewrite everything.
+    */
+   list = file->idat->idat_list_tail;
+
+   if (list->count == list->length)
+   {
+      list = IDAT_list_extend(list);
+
+      if (list == NULL)
+         stop(file, READ_ERROR_CODE, "out of memory");
+
+      /* Move to the next block */
+      list->count = 0;
+      file->idat->idat_list_tail = list;
+   }
+
+   /* And fill in the next IDAT information buffer. */
+   list->lengths[(list->count)++] = file->chunk->chunk_length;
+
+   /* The type of the next chunk was recorded in the file control structure by
+    * the caller, if this is png_IDAT return 'skip' to the caller.
+    */
+   if (file->type == png_IDAT)
+      return 0; /* skip this for the moment */
+
+   /* This is the final IDAT chunk, so run the tests to check for the too far
+    * back error and possibly optimize the window bits.  This means going back
+    * to the start of the first chunk data, which is stored in the original
+    * chunk allocation.
+    */
+   setpos(file->chunk);
+
+   if (zlib_check(file, 0))
+   {
+      struct IDAT *idat;
+      int cmp;
+
+      /* The IDAT stream was successfully uncompressed; see whether it
+       * contained the correct number of bytes of image data.
+       */
+      cmp = uarb_cmp(file->image_bytes, file->image_digits,
+         file->chunk->uncompressed_bytes, file->chunk->uncompressed_digits);
+
+      if (cmp < 0)
+         type_message(file, png_IDAT, "extra uncompressed data");
+
+      else if (cmp > 0)
+         stop(file, LIBPNG_ERROR_CODE, "IDAT: uncompressed data too small");
+
+      /* Return the stream to the start of the first IDAT chunk; the length
+       * is set in the write case below but the input chunk variables must be
+       * set (once) here:
+       */
+      setpos(file->chunk);
+
+      idat = file->idat;
+      idat->idat_cur = idat->idat_list_head;
+      idat->idat_length = idat->idat_cur->lengths[0];
+      idat->idat_count = 0; /* Count of chunks read in current list */
+      idat->idat_index = 0; /* Index into chunk data */
+
+      /* Update the chunk length to the correct value for the IDAT chunk: */
+      file->chunk->chunk_length = rechunk_length(idat, 1/*start*/);
+
+      /* Change the state to writing IDAT chunks */
+      file->state = STATE_IDAT;
+
+      return 1;
+   }
+
+   else /* Failure to decompress the IDAT stream; give up. */
+      stop(file, ZLIB_ERROR_CODE, "could not uncompress IDAT");
+}
+
+/* ZLIB CONTROL STRUCTURE */
+struct zlib
+{
+   /* ANCESTORS */
+   struct IDAT *  idat;          /* NOTE: May be NULL */
+   struct chunk * chunk;
+   struct file *  file;
+   struct global *global;
+
+   /* GLOBAL ZLIB INFORMATION: SET BY THE CALLER */
+   png_uint_32    rewrite_offset;
+
+   /* GLOBAL ZLIB INFORMATION: SET BY THE ZLIB READ CODE */
+   udigit         compressed_bytes[5];
+   int            compressed_digits;
+   udigit         uncompressed_bytes[5];
+   int            uncompressed_digits;
+   int            file_bits;             /* window bits from the file */
+   int            ok_bits;               /* Set <16 on a successful read */
+   int            cksum;                 /* Set on a checksum error */
+
+   /* PROTECTED ZLIB INFORMATION: USED BY THE ZLIB ROUTINES */
+   z_stream       z;
+   png_uint_32    extra_bytes;   /* Count of extra compressed bytes */
+   int            state;
+   int            rc;            /* Last return code */
+   int            window_bits;   /* 0 if no change */
+   png_byte       header[2];
+};
+
+static const char *
+zlib_flevel(struct zlib *zlib)
+{
+   switch (zlib->header[1] >> 6)
+   {
+      case 0:  return "supfast";
+      case 1:  return "stdfast";
+      case 2:  return "default";
+      case 3:  return "maximum";
+      default: assert(UNREACHED);
+   }
+
+   return "COMPILER BUG";
+}
+
+static const char *
+zlib_rc(struct zlib *zlib)
+   /* Return a string for the zlib return code */
+{
+   switch (zlib->rc)
+   {
+      case Z_OK:              return "Z_OK";
+      case Z_STREAM_END:      return "Z_STREAM_END";
+      case Z_NEED_DICT:       return "Z_NEED_DICT";
+      case Z_ERRNO:           return "Z_ERRNO";
+      case Z_STREAM_ERROR:    return "Z_STREAM_ERROR";
+      case Z_DATA_ERROR:      return "Z_DATA_ERROR";
+      case Z_MEM_ERROR:       return "Z_MEM_ERROR";
+      case Z_BUF_ERROR:       return "Z_BUF_ERROR";
+      case Z_VERSION_ERROR:   return "Z_VERSION_ERROR";
+      default:                return "Z_*INVALID_RC*";
+   }
+}
+
+static void
+zlib_message(struct zlib *zlib, int unexpected)
+   /* Output a message given a zlib rc */
+{
+   if (zlib->global->errors)
+   {
+      const char *reason = zlib->z.msg;
+
+      if (reason == NULL)
+         reason = "[no message]";
+
+      fputs(zlib->file->file_name, stderr);
+      type_sep(stderr);
+      type_name(zlib->chunk->chunk_type, stderr);
+      fprintf(stderr, ": %szlib error: %d (%s) (%s)\n",
+         unexpected ? "unexpected " : "", zlib->rc, zlib_rc(zlib), reason);
+   }
+}
+
+static void
+zlib_end(struct zlib *zlib)
+{
+   /* Output the summary line now; this ensures a summary line always gets
+    * output regardless of the manner of exit.
+    */
+   if (!zlib->global->quiet)
+   {
+      if (zlib->ok_bits < 16) /* stream was read ok */
+      {
+         const char *reason;
+
+         if (zlib->cksum)
+            reason = "CHK"; /* checksum error */
+
+         else if (zlib->ok_bits > zlib->file_bits)
+            reason = "TFB"; /* fixing a too-far-back error */
+
+         else if (zlib->ok_bits == zlib->file_bits)
+            reason = "OK ";
+
+         else
+            reason = "OPT"; /* optimizing window bits */
+
+         /* SUMMARY FORMAT (for a successful zlib inflate):
+          *
+          * IDAT reason flevel file-bits ok-bits compressed uncompressed file
+          */
+         type_name(zlib->chunk->chunk_type, stdout);
+         printf(" %s %s %d %d ", reason, zlib_flevel(zlib), zlib->file_bits,
+            zlib->ok_bits);
+         uarb_print(zlib->compressed_bytes, zlib->compressed_digits, stdout);
+         putc(' ', stdout);
+         uarb_print(zlib->uncompressed_bytes, zlib->uncompressed_digits,
+            stdout);
+         putc(' ', stdout);
+         fputs(zlib->file->file_name, stdout);
+         putc('\n', stdout);
+      }
+
+      else
+      {
+         /* This is a zlib read error; the chunk will be skipped.  For an IDAT
+          * stream this will also cause a fatal read error (via stop()).
+          *
+          * SUMMARY FORMAT:
+          *
+          * IDAT SKP flevel file-bits z-rc compressed message file
+          *
+          * z-rc is the zlib failure code; message is the error message with
+          * spaces replaced by '-'.  The compressed byte count indicates where
+          * in the zlib stream the error occurred.
+          */
+         type_name(zlib->chunk->chunk_type, stdout);
+         printf(" SKP %s %d %s ", zlib_flevel(zlib), zlib->file_bits,
+            zlib_rc(zlib));
+         uarb_print(zlib->compressed_bytes, zlib->compressed_digits, stdout);
+         putc(' ', stdout);
+         emit_string(zlib->z.msg ? zlib->z.msg : "[no_message]", stdout);
+         putc(' ', stdout);
+         fputs(zlib->file->file_name, stdout);
+         putc('\n', stdout);
+      }
+   }
+
+   if (zlib->state >= 0)
+   {
+      zlib->rc = inflateEnd(&zlib->z);
+
+      if (zlib->rc != Z_OK)
+         zlib_message(zlib, 1/*unexpected*/);
+   }
+
+   CLEAR(*zlib);
+}
+
+static int
+zlib_reset(struct zlib *zlib, int window_bits)
+   /* Reinitializes a zlib with a different window_bits */
+{
+   assert(zlib->state >= 0); /* initialized by zlib_init */
+
+   zlib->z.next_in = Z_NULL;
+   zlib->z.avail_in = 0;
+   zlib->z.next_out = Z_NULL;
+   zlib->z.avail_out = 0;
+
+   zlib->window_bits = window_bits;
+   zlib->compressed_digits = 0;
+   zlib->uncompressed_digits = 0;
+
+   zlib->state = 0; /* initialized, once */
+   zlib->rc = inflateReset2(&zlib->z, 0);
+   if (zlib->rc != Z_OK)
+   {
+      zlib_message(zlib, 1/*unexpected*/);
+      return 0;
+   }
+
+   return 1;
+}
+
+static int
+zlib_init(struct zlib *zlib, struct IDAT *idat, struct chunk *chunk,
+   int window_bits, png_uint_32 offset)
+   /* Initialize a zlib_control; the result is true/false */
+{
+   CLEAR(*zlib);
+
+   zlib->idat = idat;
+   zlib->chunk = chunk;
+   zlib->file = chunk->file;
+   zlib->global = chunk->global;
+   zlib->rewrite_offset = offset; /* never changed for this zlib */
+
+   /* *_out does not need to be set: */
+   zlib->z.next_in = Z_NULL;
+   zlib->z.avail_in = 0;
+   zlib->z.zalloc = Z_NULL;
+   zlib->z.zfree = Z_NULL;
+   zlib->z.opaque = Z_NULL;
+
+   zlib->state = -1;
+   zlib->window_bits = window_bits;
+
+   zlib->compressed_digits = 0;
+   zlib->uncompressed_digits = 0;
+
+   /* These values are sticky across reset (in addition to the stuff in the
+    * first block, which is actually constant.)
+    */
+   zlib->file_bits = 24;
+   zlib->ok_bits = 16; /* unset */
+   zlib->cksum = 0; /* set when a checksum error is detected */
+
+   /* '0' means use the header; inflateInit2 should always succeed because it
+    * does nothing apart from allocating the internal zstate.
+    */
+   zlib->rc = inflateInit2(&zlib->z, 0);
+   if (zlib->rc != Z_OK)
+   {
+      zlib_message(zlib, 1/*unexpected*/);
+      return 0;
+   }
+
+   else
+   {
+      zlib->state = 0; /* initialized */
+      return 1;
+   }
+}
+
+static int
+max_window_bits(uarbc size, int ndigits)
+   /* Return the zlib stream window bits required for data of the given size. */
+{
+   png_uint_16 cb;
+
+   if (ndigits > 1)
+      return 15;
+
+   cb = size[0];
+
+   if (cb > 16384) return 15;
+   if (cb >  8192) return 14;
+   if (cb >  4096) return 13;
+   if (cb >  2048) return 12;
+   if (cb >  1024) return 11;
+   if (cb >   512) return 10;
+   if (cb >   256) return  9;
+   return 8;
+}
+
+static int
+zlib_advance(struct zlib *zlib, png_uint_32 nbytes)
+   /* Read nbytes compressed bytes; the stream will be initialized if required.
+    * Bytes are always being reread and errors are fatal.  The return code is as
+    * follows:
+    *
+    *    -1: saw the "too far back" error
+    *     0: ok, keep going
+    *     1: saw Z_STREAM_END (zlib->extra_bytes indicates too much data)
+    *     2: a zlib error that cannot be corrected (error message already
+    *        output if required.)
+    */
+#  define ZLIB_TOO_FAR_BACK (-1)
+#  define ZLIB_OK           0
+#  define ZLIB_STREAM_END   1
+#  define ZLIB_FATAL        2
+{
+   int state = zlib->state;
+   int endrc = ZLIB_OK;
+   png_uint_32 in_bytes = 0;
+   struct file *file = zlib->file;
+
+   assert(state >= 0);
+
+   while (in_bytes < nbytes && endrc == ZLIB_OK)
+   {
+      png_uint_32 out_bytes;
+      int flush;
+      png_byte bIn = reread_byte(file);
+      png_byte bOut;
+
+      switch (state)
+      {
+         case 0: /* first header byte */
+            {
+               int file_bits = 8+(bIn >> 4);
+               int new_bits = zlib->window_bits;
+
+               zlib->file_bits = file_bits;
+
+               /* Check against the existing value - it may not need to be
+                * changed.  Note that a bogus file_bits is allowed through once,
+                * to see if it works, but the window_bits value is set to 15,
+                * the maximum.
+                */
+               if (new_bits == 0) /* no change */
+                  zlib->window_bits = ((file_bits > 15) ? 15 : file_bits);
+
+               else if (new_bits != file_bits) /* rewrite required */
+                  bIn = (png_byte)((bIn & 0xf) + ((new_bits-8) << 4));
+            }
+
+            zlib->header[0] = bIn;
+            zlib->state = state = 1;
+            break;
+
+         case 1: /* second header byte */
+            {
+               int b2 = bIn & 0xe0; /* top 3 bits */
+
+               /* The checksum calculation, on the first 11 bits: */
+               b2 += 0x1f - ((zlib->header[0] << 8) + b2) % 0x1f;
+
+               /* Update the checksum byte if required: */
+               if (bIn != b2)
+               {
+                  /* If the first byte wasn't changed this indicates an error in
+                   * the checksum calculation; signal this by setting 'cksum'.
+                   */
+                  if (zlib->file_bits == zlib->window_bits)
+                     zlib->cksum = 1;
+
+                  bIn = (png_byte)b2;
+               }
+            }
+
+            zlib->header[1] = bIn;
+            zlib->state = state = 2;
+            break;
+
+         default: /* After the header bytes */
+            break;
+      }
+
+      /* For some streams, perhaps only those compressed with 'superfast
+       * compression' (which results in a lot of copying) Z_BUF_ERROR can happen
+       * immediately after all output has been flushed on the next input byte.
+       * This is handled below when Z_BUF_ERROR is detected by adding an output
+       * byte.
+       */
+      zlib->z.next_in = &bIn;
+      zlib->z.avail_in = 1;
+      zlib->z.next_out = &bOut;
+      zlib->z.avail_out = 0;     /* Initially */
+
+      /* Initially use Z_NO_FLUSH in an attempt to persuade zlib to look at this
+       * byte without confusing what is going on with output.
+       */
+      flush = Z_NO_FLUSH;
+      out_bytes = 0;
+
+      /* NOTE: expression 3 is only evaluated on 'continue', because of the
+       * 'break' at the end of this loop below.
+       */
+      for (;endrc == ZLIB_OK;
+         flush = Z_SYNC_FLUSH,
+         zlib->z.next_out = &bOut,
+         zlib->z.avail_out = 1,
+         ++out_bytes)
+      {
+         zlib->rc = inflate(&zlib->z, flush);
+         out_bytes -= zlib->z.avail_out;
+
+         switch (zlib->rc)
+         {
+            case Z_BUF_ERROR:
+               if (zlib->z.avail_out == 0)
+                  continue; /* Try another output byte. */
+
+               if (zlib->z.avail_in == 0)
+                  break; /* Try another input byte */
+
+               /* Both avail_out and avail_in are 1 yet zlib returned a code
+                * indicating no progress was possible.  This is unexpected.
+                */
+               zlib_message(zlib, 1/*unexpected*/);
+               endrc = ZLIB_FATAL; /* stop processing */
+               break;
+
+            case Z_OK:
+               /* Zlib is supposed to have made progress: */
+               assert(zlib->z.avail_out == 0 || zlib->z.avail_in == 0);
+               continue;
+
+            case Z_STREAM_END:
+               /* This is the successful end. */
+               zlib->state = 3; /* end of stream */
+               endrc = ZLIB_STREAM_END;
+               break;
+
+            case Z_NEED_DICT:
+               zlib_message(zlib, 0/*stream error*/);
+               endrc = ZLIB_FATAL;
+               break;
+
+            case Z_DATA_ERROR:
+               /* The too far back error can be corrected, others cannot: */
+               if (zlib->z.msg != NULL &&
+                  strcmp(zlib->z.msg, "invalid distance too far back") == 0)
+               {
+                  endrc = ZLIB_TOO_FAR_BACK;
+                  break;
+               }
+               /* FALLTHROUGH */
+
+            default:
+               zlib_message(zlib, 0/*stream error*/);
+               endrc = ZLIB_FATAL;
+               break;
+         } /* switch (inflate rc) */
+
+         /* Control gets here when further output is not possible; endrc may
+          * still be ZLIB_OK if more input is required.
+          */
+         break;
+      } /* for (output bytes) */
+
+      /* Keep a running count of output byte produced: */
+      zlib->uncompressed_digits = uarb_add32(zlib->uncompressed_bytes,
+         zlib->uncompressed_digits, out_bytes);
+
+      /* Keep going, the loop will terminate when endrc is no longer set to
+       * ZLIB_OK or all the input bytes have been consumed; meanwhile keep
+       * adding input bytes.
+       */
+      assert(zlib->z.avail_in == 0 || endrc != ZLIB_OK);
+
+      in_bytes += 1 - zlib->z.avail_in;
+   } /* while (input bytes) */
+
+   assert(in_bytes == nbytes || endrc != ZLIB_OK);
+
+   /* Update the running total of input bytes consumed */
+   zlib->compressed_digits = uarb_add32(zlib->compressed_bytes,
+      zlib->compressed_digits, in_bytes - zlib->z.avail_in);
+
+   /* At the end of the stream update the chunk with the accumulated
+    * information if it is an improvement:
+    */
+   if (endrc == ZLIB_STREAM_END && zlib->window_bits < zlib->ok_bits)
+   {
+      struct chunk *chunk = zlib->chunk;
+
+      chunk->uncompressed_digits = uarb_copy(chunk->uncompressed_bytes,
+         zlib->uncompressed_bytes, zlib->uncompressed_digits);
+      chunk->compressed_digits = uarb_copy(chunk->compressed_bytes,
+         zlib->compressed_bytes, zlib->compressed_digits);
+      chunk->rewrite_buffer[0] = zlib->header[0];
+      chunk->rewrite_buffer[1] = zlib->header[1];
+
+      if (zlib->window_bits != zlib->file_bits || zlib->cksum)
+      {
+         /* A rewrite is required */
+         chunk->rewrite_offset = zlib->rewrite_offset;
+         chunk->rewrite_length = 2;
+      }
+
+      else
+      {
+         chunk->rewrite_offset = 0;
+         chunk->rewrite_length = 0;
+      }
+
+      if (in_bytes < nbytes)
+         chunk_message(chunk, "extra compressed data");
+
+      zlib->extra_bytes = nbytes - in_bytes;
+      zlib->ok_bits = zlib->window_bits;
+   }
+
+   return endrc;
+}
+
+static int
+zlib_run(struct zlib *zlib)
+   /* Like zlib_advance but also handles a stream of IDAT chunks. */
+{
+   /* The 'extra_bytes' field is set by zlib_advance if there is extra
+    * compressed data in the chunk it handles (if it sees Z_STREAM_END before
+    * all the input data has been used.)  This function uses the value to update
+    * the correct chunk length, so the problem should only ever be detected once
+    * for each chunk.  zlib_advance outputs the error message, though see the
+    * IDAT specific check below.
+    */
+   zlib->extra_bytes = 0;
+
+   if (zlib->idat != NULL)
+   {
+      struct IDAT_list *list = zlib->idat->idat_list_head;
+      struct IDAT_list *last = zlib->idat->idat_list_tail;
+      int        skip = 0;
+
+      /* 'rewrite_offset' is the offset of the LZ data within the chunk, for
+       * IDAT it should be 0:
+       */
+      assert(zlib->rewrite_offset == 0);
+
+      /* Process each IDAT_list in turn; the caller has left the stream
+       * positioned at the start of the first IDAT chunk data.
+       */
+      for (;;)
+      {
+         unsigned int count = list->count;
+         unsigned int i;
+
+         for (i = 0; i<count; ++i)
+         {
+            int rc;
+
+            if (skip > 0) /* Skip CRC and next IDAT header */
+               skip_12(zlib->file);
+
+            skip = 12; /* for the next time */
+
+            rc = zlib_advance(zlib, list->lengths[i]);
+
+            switch (rc)
+            {
+               case ZLIB_OK: /* keep going */
+                  break;
+
+               case ZLIB_STREAM_END: /* stop */
+                  /* There may be extra chunks; if there are and one of them is
+                   * not zero length output the 'extra data' message.  Only do
+                   * this check if errors are being output.
+                   */
+                  if (zlib->global->errors && zlib->extra_bytes == 0)
+                  {
+                     struct IDAT_list *check = list;
+                     int j = i+1, jcount = count;
+
+                     for (;;)
+                     {
+                        for (; j<jcount; ++j)
+                           if (check->lengths[j] > 0)
+                           {
+                              chunk_message(zlib->chunk,
+                                 "extra compressed data");
+                              goto end_check;
+                           }
+
+                        if (check == last)
+                           break;
+
+                        check = check->next;
+                        jcount = check->count;
+                        j = 0;
+                     }
+                  }
+
+               end_check:
+                  /* Terminate the list at the current position, reducing the
+                   * length of the last IDAT too if required.
+                   */
+                  list->lengths[i] -= zlib->extra_bytes;
+                  list->count = i+1;
+                  zlib->idat->idat_list_tail = list;
+                  /* FALLTHROUGH */
+
+               default:
+                  return rc;
+            }
+         }
+
+         /* At the end of the compressed data and Z_STREAM_END was not seen. */
+         if (list == last)
+            return ZLIB_OK;
+
+         list = list->next;
+      }
+   }
+
+   else
+   {
+      struct chunk *chunk = zlib->chunk;
+      int rc;
+
+      assert(zlib->rewrite_offset < chunk->chunk_length);
+
+      rc = zlib_advance(zlib, chunk->chunk_length - zlib->rewrite_offset);
+
+      /* The extra bytes in the chunk are handled now by adjusting the chunk
+       * length to exclude them; the zlib data is always stored at the end of
+       * the PNG chunk (although clearly this is not necessary.)  zlib_advance
+       * has already output a warning message.
+       */
+      chunk->chunk_length -= zlib->extra_bytes;
+      return rc;
+   }
+}
+
+static int /* global function; not a member function */
+zlib_check(struct file *file, png_uint_32 offset)
+   /* Check the stream of zlib compressed data in either idat (if given) or (if
+    * not) chunk.  In fact it is zlib_run that handles the difference in reading
+    * a single chunk and a list of IDAT chunks.
+    *
+    * In either case the input file must be positioned at the first byte of zlib
+    * compressed data (the first header byte).
+    *
+    * The return value is true on success, including the case where the zlib
+    * header may need to be rewritten, and false on an unrecoverable error.
+    *
+    * In the case of IDAT chunks 'offset' should be 0.
+    */
+{
+   fpos_t start_pos;
+   struct zlib zlib;
+
+   /* Record the start of the LZ data to allow a re-read. */
+   file_getpos(file, &start_pos);
+
+   /* First test the existing (file) window bits: */
+   if (zlib_init(&zlib, file->idat, file->chunk, 0/*window bits*/, offset))
+   {
+      int min_bits, max_bits, rc;
+
+      /* The first run using the existing window bits. */
+      rc = zlib_run(&zlib);
+
+      switch (rc)
+      {
+         case ZLIB_TOO_FAR_BACK:
+            /* too far back error */
+            file->status_code |= TOO_FAR_BACK;
+            min_bits = zlib.window_bits + 1;
+            max_bits = 15;
+            break;
+
+         case ZLIB_STREAM_END:
+            if (!zlib.global->optimize_zlib &&
+               zlib.window_bits == zlib.file_bits && !zlib.cksum)
+            {
+               /* The trivial case where the stream is ok and optimization was
+                * not requested.
+                */
+               zlib_end(&zlib);
+               return 1;
+            }
+
+            max_bits = max_window_bits(zlib.uncompressed_bytes,
+               zlib.uncompressed_digits);
+            if (zlib.ok_bits < max_bits)
+               max_bits = zlib.ok_bits;
+            min_bits = 8;
+
+            /* cksum is set if there is an error in the zlib header checksum
+             * calculation in the original file (and this may be the only reason
+             * a rewrite is required).  We can't rely on the file window bits in
+             * this case, so do the optimization anyway.
+             */
+            if (zlib.cksum)
+               chunk_message(zlib.chunk, "zlib checksum");
+            break;
+
+
+         case ZLIB_OK:
+            /* Truncated stream; unrecoverable, gets converted to ZLIB_FATAL */
+            zlib.z.msg = PNGZ_MSG_CAST("[truncated]");
+            zlib_message(&zlib, 0/*expected*/);
+            /* FALLTHROUGH */
+
+         default:
+            /* Unrecoverable error; skip the chunk; a zlib_message has already
+             * been output.
+             */
+            zlib_end(&zlib);
+            return 0;
+      }
+
+      /* Optimize window bits or fix a too-far-back error.  min_bits and
+       * max_bits have been set appropriately, ok_bits records the bit value
+       * known to work.
+       */
+      while (min_bits < max_bits || max_bits < zlib.ok_bits/*if 16*/)
+      {
+         int test_bits = (min_bits + max_bits) >> 1;
+
+         if (zlib_reset(&zlib, test_bits))
+         {
+            file_setpos(file, &start_pos);
+            rc = zlib_run(&zlib);
+
+            switch (rc)
+            {
+               case ZLIB_TOO_FAR_BACK:
+                  min_bits = test_bits+1;
+                  if (min_bits > max_bits)
+                  {
+                     /* This happens when the stream really is damaged and it
+                      * contains a distance code that addresses bytes before
+                      * the start of the uncompressed data.
+                      */
+                     assert(test_bits == 15);
+
+                     /* Output the error that wasn't output before: */
+                     if (zlib.z.msg == NULL)
+                        zlib.z.msg = PNGZ_MSG_CAST(
+                           "invalid distance too far back");
+                     zlib_message(&zlib, 0/*stream error*/);
+                     zlib_end(&zlib);
+                     return 0;
+                  }
+                  break;
+
+               case ZLIB_STREAM_END: /* success */
+                  max_bits = test_bits;
+                  break;
+
+               default:
+                  /* A fatal error; this happens if a too-far-back error was
+                   * hiding a more serious error, zlib_advance has already
+                   * output a zlib_message.
+                   */
+                  zlib_end(&zlib);
+                  return 0;
+            }
+         }
+
+         else /* inflateReset2 failed */
+         {
+            zlib_end(&zlib);
+            return 0;
+         }
+      }
+
+      /* The loop guarantees this */
+      assert(zlib.ok_bits == max_bits);
+      zlib_end(&zlib);
+      return 1;
+   }
+
+   else /* zlib initialization failed - skip the chunk */
+   {
+      zlib_end(&zlib);
+      return 0;
+   }
+}
+
+/***************************** LIBPNG CALLBACKS *******************************/
+/* The strategy here is to run a regular libpng PNG file read but examine the
+ * input data (from the file) before passing it to libpng so as to be aware of
+ * the state we expect libpng to be in.  Warning and error callbacks are also
+ * intercepted so that they can be quieted and interpreted.  Interpretation
+ * depends on a somewhat risky string match for known error messages; let us
+ * hope that this can be fixed in the next version of libpng.
+ *
+ * The control structure is pointed to by the libpng error pointer.  It contains
+ * that set of structures which must persist across multiple read callbacks,
+ * which is pretty much everything except the 'zlib' control structure.
+ *
+ * The file structure is instantiated in the caller of the per-file routine, but
+ * the per-file routine contains the chunk and IDAT control structures.
+ */
+/* The three routines read_chunk, process_chunk and sync_stream can only be
+ * called via a call to read_chunk and only exit at a return from process_chunk.
+ * These routines could have been written as one confusing large routine,
+ * instead this code relies on the compiler to do tail call elimination.  The
+ * possible calls are as follows:
+ *
+ * read_chunk
+ *    -> sync_stream
+ *       -> process_chunk
+ *    -> process_chunk
+ *       -> read_chunk
+ *       returns
+ */
+static void read_chunk(struct file *file);
+static void
+process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length,
+   png_uint_32 next_type)
+   /* Called when the chunk data has been read, next_length and next_type
+    * will be set for the next chunk (or 0 if this is IEND).
+    *
+    * When this routine returns, chunk_length and chunk_type will be set for the
+    * next chunk to write because if a chunk is skipped this return calls back
+    * to read_chunk.
+    */
+{
+   png_uint_32 type = file->type;
+
+   if (file->global->verbose > 1)
+   {
+      fputs("  ", stderr);
+      type_name(file->type, stderr);
+      fprintf(stderr, " %lu 0x%.8x 0x%.8x\n", (unsigned long)file->length,
+         file->crc ^ 0xffffffff, file_crc);
+   }
+
+   /* The basic structure seems correct but the CRC may not match, in this
+    * case assume that it is simply a bad CRC, either wrongly calculated or
+    * because of damaged stream data.
+    */
+   if ((file->crc ^ 0xffffffff) != file_crc)
+   {
+      /* The behavior is set by the 'skip' setting; if it is anything other
+       * than SKIP_BAD_CRC ignore the bad CRC and return the chunk, with a
+       * corrected CRC and possibly processed, to libpng.  Otherwise skip the
+       * chunk, which will result in a fatal error if the chunk is critical.
+       */
+      file->status_code |= CRC_ERROR;
+
+      /* Ignore the bad CRC  */
+      if (file->global->skip != SKIP_BAD_CRC)
+         type_message(file, type, "bad CRC");
+
+      /* This will cause an IEND with a bad CRC to stop */
+      else if (CRITICAL(type))
+         stop(file, READ_ERROR_CODE, "bad CRC in critical chunk");
+
+      else
+      {
+         type_message(file, type, "skipped: bad CRC");
+
+         /* NOTE: this cannot be reached for IEND because it is critical. */
+         goto skip_chunk;
+      }
+   }
+
+   /* Check for other 'skip' cases and handle these; these only apply to
+    * ancillary chunks (and not tRNS, which should probably have been a critical
+    * chunk.)
+    */
+   if (skip_chunk_type(file->global, type))
+      goto skip_chunk;
+
+   /* The chunk may still be skipped if problems are detected in the LZ data,
+    * however the LZ data check requires a chunk.  Handle this by instantiating
+    * a chunk unless an IDAT is already instantiated (IDAT control structures
+    * instantiate their own chunk.)
+    */
+   if (type != png_IDAT)
+      file->alloc(file, 0/*chunk*/);
+
+   else if (file->idat == NULL)
+      file->alloc(file, 1/*IDAT*/);
+
+   else
+   {
+      /* The chunk length must be updated for process_IDAT */
+      assert(file->chunk != NULL);
+      assert(file->chunk->chunk_type == png_IDAT);
+      file->chunk->chunk_length = file->length;
+   }
+
+   /* Record the 'next' information too, now that the original values for
+    * this chunk have been copied.  Notice that the IDAT chunks only make a
+    * copy of the position of the first chunk, this is fine - process_IDAT does
+    * not need the position of this chunk.
+    */
+   file->length = next_length;
+   file->type = next_type;
+   getpos(file);
+
+   /* Do per-type processing, note that if this code does not return from the
+    * function the chunk will be skipped.  The rewrite is cancelled here so that
+    * it can be set in the per-chunk processing.
+    */
+   file->chunk->rewrite_length = 0;
+   file->chunk->rewrite_offset = 0;
+   switch (type)
+   {
+      default:
+         return;
+
+      case png_IHDR:
+         /* Read this now and update the control structure with the information
+          * it contains.  The header is validated completely to ensure this is a
+          * PNG.
+          */
+         {
+            struct chunk *chunk = file->chunk;
+
+            if (chunk->chunk_length != 13)
+               stop_invalid(file, "IHDR length");
+
+            /* Read all the IHDR information and validate it. */
+            setpos(chunk);
+            file->width = reread_4(file);
+            file->height = reread_4(file);
+            file->bit_depth = reread_byte(file);
+            file->color_type = reread_byte(file);
+            file->compression_method = reread_byte(file);
+            file->filter_method = reread_byte(file);
+            file->interlace_method = reread_byte(file);
+
+            /* This validates all the fields, and calls stop_invalid if
+             * there is a problem.
+             */
+            calc_image_size(file);
+         }
+         return;
+
+         /* Ancillary chunks that require further processing: */
+      case png_zTXt: case png_iCCP:
+         if (process_zTXt_iCCP(file))
+            return;
+         chunk_end(&file->chunk);
+         file_setpos(file, &file->data_pos);
+         break;
+
+      case png_iTXt:
+         if (process_iTXt(file))
+            return;
+         chunk_end(&file->chunk);
+         file_setpos(file, &file->data_pos);
+         break;
+
+      case png_IDAT:
+         if (process_IDAT(file))
+            return;
+         /* First pass: */
+         assert(next_type == png_IDAT);
+         break;
+   }
+
+   /* Control reaches this point if the chunk must be skipped.  For chunks other
+    * than IDAT this means that the zlib compressed data is fatally damaged and
+    * the chunk will not be passed to libpng.  For IDAT it means that the end of
+    * the IDAT stream has not yet been reached and we must handle the next
+    * (IDAT) chunk.  If the LZ data in an IDAT stream cannot be read 'stop' must
+    * be used to halt parsing of the PNG.
+    */
+   read_chunk(file);
+   return;
+
+   /* This is the generic code to skip the current chunk; simply jump to the
+    * next one.
+    */
+skip_chunk:
+   file->length = next_length;
+   file->type = next_type;
+   getpos(file);
+   read_chunk(file);
+}
+
+static png_uint_32
+get32(png_bytep buffer, int offset)
+   /* Read a 32-bit value from an 8-byte circular buffer (used only below).
+    */
+{
+   return
+      (buffer[ offset    & 7] << 24) +
+      (buffer[(offset+1) & 7] << 16) +
+      (buffer[(offset+2) & 7] <<  8) +
+      (buffer[(offset+3) & 7]      );
+}
+
+static void
+sync_stream(struct file *file)
+   /* The stream seems to be messed up, attempt to resync from the current chunk
+    * header.  Executes stop on a fatal error, otherwise calls process_chunk.
+    */
+{
+   png_uint_32 file_crc;
+
+   file->status_code |= STREAM_ERROR;
+
+   if (file->global->verbose)
+   {
+      fputs(" SYNC ", stderr);
+      type_name(file->type, stderr);
+      putc('\n', stderr);
+   }
+
+   /* Return to the start of the chunk data */
+   file_setpos(file, &file->data_pos);
+   file->read_count = 8;
+
+   if (read_4(file, &file_crc) == 4) /* else completely truncated */
+   {
+      /* Ignore the recorded chunk length, proceed through the data looking for
+       * a leading sequence of bytes that match the CRC in the following four
+       * bytes.  Each time a match is found check the next 8 bytes for a valid
+       * length, chunk-type pair.
+       */
+      png_uint_32 length;
+      png_uint_32 type = file->type;
+      png_uint_32 crc = crc_init_4(type);
+      png_byte buffer[8];
+      unsigned int nread = 0, nused = 0;
+
+      for (length=0; length <= 0x7fffffff; ++length)
+      {
+         int ch;
+
+         if ((crc ^ 0xffffffff) == file_crc)
+         {
+            /* A match on the CRC; for IEND this is sufficient, but for anything
+             * else expect a following chunk header.
+             */
+            if (type == png_IEND)
+            {
+               file->length = length;
+               process_chunk(file, file_crc, 0, 0);
+               return;
+            }
+
+            else
+            {
+               /* Need 8 bytes */
+               while (nread < 8+nused)
+               {
+                  ch = read_byte(file);
+                  if (ch == EOF)
+                     goto truncated;
+                  buffer[(nread++) & 7] = (png_byte)ch;
+               }
+
+               /* Prevent overflow */
+               nread -= nused & ~7;
+               nused -= nused & ~7; /* or, nused &= 7 ;-) */
+
+               /* Examine the 8 bytes for a valid chunk header. */
+               {
+                  png_uint_32 next_length = get32(buffer, nused);
+
+                  if (next_length < 0x7fffffff)
+                  {
+                     png_uint_32 next_type = get32(buffer, nused+4);
+
+                     if (chunk_type_valid(next_type))
+                     {
+                        file->read_count -= 8;
+                        process_chunk(file, file_crc, next_length, next_type);
+                        return;
+                     }
+                  }
+
+                  /* Not valid, keep going. */
+               }
+            }
+         }
+
+         /* This catches up with the circular buffer which gets filled above
+          * while checking a chunk header.  This code is slightly tricky - if
+          * the chunk_type is IEND the buffer will never be used, if it is not
+          * the code will always read ahead exactly 8 bytes and pass this on to
+          * process_chunk.  So the invariant that IEND leaves the file position
+          * after the IEND CRC and other chunk leave it after the *next* chunk
+          * header is not broken.
+          */
+         if (nread <= nused)
+         {
+            ch = read_byte(file);
+
+            if (ch == EOF)
+               goto truncated;
+         }
+
+         else
+            ch = buffer[(++nused) & 7];
+
+         crc = crc_one_byte(crc, file_crc >> 24);
+         file_crc = (file_crc << 8) + ch;
+      }
+
+      /* Control gets to here if when 0x7fffffff bytes (plus 8) have been read,
+       * ok, treat this as a damaged stream too:
+       */
+   }
+
+truncated:
+   stop(file, READ_ERROR_CODE, "damaged PNG stream");
+}
+
+static void
+read_chunk(struct file *file)
+   /* On entry file::data_pos must be set to the position of the first byte
+    * of the chunk data *and* the input file must be at this position.  This
+    * routine (via process_chunk) instantiates a chunk or IDAT control structure
+    * based on file::length and file::type and also resets these fields and
+    * file::data_pos for the chunk after this one.  For an IDAT chunk the whole
+    * stream of IDATs will be read, until something other than an IDAT is
+    * encountered, and the file fields will be set for the chunk after the end
+    * of the stream of IDATs.
+    *
+    * For IEND the file::type field will be set to 0, and nothing beyond the end
+    * of the IEND chunk will have been read.
+    */
+{
+   png_uint_32 length = file->length;
+   png_uint_32 type = file->type;
+
+   /* After IEND file::type is set to 0, if libpng attempts to read
+    * more data at this point this is a bug in libpng.
+    */
+   if (type == 0)
+      stop(file, UNEXPECTED_ERROR_CODE, "read beyond IEND");
+
+   if (file->global->verbose > 2)
+   {
+      fputs("   ", stderr);
+      type_name(type, stderr);
+      fprintf(stderr, " %lu\n", (unsigned long)length);
+   }
+
+   /* Start the read_crc calculation with the chunk type, then read to the end
+    * of the chunk data (without processing it in any way) to check that it is
+    * all there and calculate the CRC.
+    */
+   file->crc = crc_init_4(type);
+   if (crc_read_many(file, length)) /* else it was truncated */
+   {
+      png_uint_32 file_crc; /* CRC read from file */
+      unsigned int nread = read_4(file, &file_crc);
+
+      if (nread == 4)
+      {
+         if (type != png_IEND) /* do not read beyond IEND */
+         {
+            png_uint_32 next_length;
+
+            nread += read_4(file, &next_length);
+            if (nread == 8 && next_length <= 0x7fffffff)
+            {
+               png_uint_32 next_type;
+
+               nread += read_4(file, &next_type);
+
+               if (nread == 12 && chunk_type_valid(next_type))
+               {
+                  /* Adjust the read count back to the correct value for this
+                   * chunk.
+                   */
+                  file->read_count -= 8;
+                  process_chunk(file, file_crc, next_length, next_type);
+                  return;
+               }
+            }
+         }
+
+         else /* IEND */
+         {
+            process_chunk(file, file_crc, 0, 0);
+            return;
+         }
+      }
+   }
+
+   /* Control gets to here if the stream seems invalid or damaged in some
+    * way.  Either there was a problem reading all the expected data (this
+    * chunk's data, its CRC and the length and type of the next chunk) or the
+    * next chunk length/type are invalid.  Notice that the cases that end up
+    * here all correspond to cases that would otherwise terminate the read of
+    * the PNG file.
+    */
+   sync_stream(file);
+}
+
+/* This returns a file* from a png_struct in an implementation specific way. */
+static struct file *get_control(png_const_structrp png_ptr);
+
+static void PNGCBAPI
+error_handler(png_structp png_ptr, png_const_charp message)
+{
+   stop(get_control(png_ptr),  LIBPNG_ERROR_CODE, message);
+}
+
+static void PNGCBAPI
+warning_handler(png_structp png_ptr, png_const_charp message)
+{
+   struct file *file = get_control(png_ptr);
+
+   if (file->global->warnings)
+      emit_error(file, LIBPNG_WARNING_CODE, message);
+}
+
+/* Read callback - this is where the work gets done to check the stream before
+ * passing it to libpng
+ */
+static void PNGCBAPI
+read_callback(png_structp png_ptr, png_bytep buffer, size_t count)
+   /* Return 'count' bytes to libpng in 'buffer' */
+{
+   struct file *file = get_control(png_ptr);
+   png_uint_32 type, length; /* For the chunk be *WRITTEN* */
+   struct chunk *chunk;
+
+   /* libpng should always ask for at least one byte */
+   if (count == 0)
+      stop(file, UNEXPECTED_ERROR_CODE, "read callback for 0 bytes");
+
+   /* The callback always reads ahead by 8 bytes - the signature or chunk header
+    * - these bytes are stored in chunk_length and chunk_type.  This block is
+    * executed once for the signature and once for the first chunk right at the
+    * start.
+    */
+   if (file->read_count < 8)
+   {
+      assert(file->read_count == 0);
+      assert((file->status_code & TRUNCATED) == 0);
+
+      (void)read_4(file, &file->length);
+
+      if (file->read_count == 4)
+         (void)read_4(file, &file->type);
+
+      if (file->read_count < 8)
+      {
+         assert((file->status_code & TRUNCATED) != 0);
+         stop(file, READ_ERROR_CODE, "not a PNG (too short)");
+      }
+
+      if (file->state == STATE_SIGNATURE)
+      {
+         if (file->length != sig1 || file->type != sig2)
+            stop(file, LIBPNG_ERROR_CODE, "not a PNG (signature)");
+
+         /* Else write it (this is the initialization of write_count, prior to
+          * this it contains CLEAR garbage.)
+          */
+         file->write_count = 0;
+      }
+
+      else
+      {
+         assert(file->state == STATE_CHUNKS);
+
+         /* The first chunk must be a well formed IHDR (this could be relaxed to
+          * use the checks in process_chunk, but that seems unnecessary.)
+          */
+         if (file->length != 13 || file->type != png_IHDR)
+            stop(file, LIBPNG_ERROR_CODE, "not a PNG (IHDR)");
+
+         /* The position of the data must be stored too */
+         getpos(file);
+      }
+   }
+
+   /* Retrieve previous state (because the read callbacks are made pretty much
+    * byte-by-byte in the sequential reader prior to 1.7).
+    */
+   chunk = file->chunk;
+
+   if (chunk != NULL)
+   {
+      length = chunk->chunk_length;
+      type = chunk->chunk_type;
+   }
+
+   else
+   {
+      /* This is the signature case; for IDAT and other chunks these values will
+       * be overwritten when read_chunk is called below.
+       */
+      length = file->length;
+      type = file->type;
+   }
+
+   do
+   {
+      png_uint_32 b;
+
+      /* Complete the read of a chunk; as a side effect this also instantiates
+       * a chunk control structure and sets the file length/type/data_pos fields
+       * for the *NEXT* chunk header.
+       *
+       * NOTE: at an IDAT any following IDAT chunks will also be read and the
+       * next_ fields will refer to the chunk after the last IDAT.
+       *
+       * NOTE: read_chunk only returns when it has read a chunk that must now be
+       * written.
+       */
+      if (file->state != STATE_SIGNATURE && chunk == NULL)
+      {
+         assert(file->read_count == 8);
+         assert(file->idat == NULL);
+         read_chunk(file);
+         chunk = file->chunk;
+         assert(chunk != NULL);
+
+         /* Do the initialization that was not done before. */
+         length = chunk->chunk_length;
+         type = chunk->chunk_type;
+
+         /* And start writing the new chunk. */
+         file->write_count = 0;
+      }
+
+      /* The chunk_ fields describe a chunk that must be written, or hold the
+       * signature.  Write the header first.  In the signature case this
+       * rewrites the signature.
+       */
+      switch (file->write_count)
+      {
+         case 0: b = length >> 24; break;
+         case 1: b = length >> 16; break;
+         case 2: b = length >>  8; break;
+         case 3: b = length      ; break;
+
+         case 4: b = type >> 24; break;
+         case 5: b = type >> 16; break;
+         case 6: b = type >>  8; break;
+         case 7: b = type      ; break;
+
+         case 8:
+            /* The header has been written.  If this is really the signature
+             * that's all that is required and we can go to normal chunk
+             * processing.
+             */
+            if (file->state == STATE_SIGNATURE)
+            {
+               /* The signature has been written, the tail call to read_callback
+                * below (it's just a goto to the start with a decent compiler)
+                * will read the IHDR header ahead and validate it.
+                */
+               assert(length == sig1 && type == sig2);
+               file->read_count = 0; /* Forces a header read */
+               file->state = STATE_CHUNKS; /* IHDR: checked above */
+               read_callback(png_ptr, buffer, count);
+               return;
+            }
+
+            else
+            {
+               assert(chunk != NULL);
+
+               /* Set up for write, notice that repositioning the input stream
+                * is only necessary if something is to be read from it.  Also
+                * notice that for the IDAT stream this must only happen once -
+                * on the first IDAT - to get back to the start of the list and
+                * this is done inside process_IDAT:
+                */
+               chunk->write_crc = crc_init_4(type);
+               if (file->state != STATE_IDAT && length > 0)
+                  setpos(chunk);
+            }
+            /* FALLTHROUGH */
+
+         default:
+            assert(chunk != NULL);
+
+            /* NOTE: the arithmetic below overflows and gives a large positive
+             * png_uint_32 value until the whole chunk data has been written.
+             */
+            switch (file->write_count - length)
+            {
+               /* Write the chunk data, normally this just comes from
+                * the file.  The only exception is for that part of a
+                * chunk which is zlib data and which must be rewritten,
+                * and IDAT chunks which can be completely
+                * reconstructed.
+                */
+               default:
+                  if (file->state == STATE_IDAT)
+                  {
+                     struct IDAT *idat = file->idat;
+
+                     assert(idat != NULL);
+
+                     /* Read an IDAT byte from the input stream of IDAT chunks.
+                      * Because the IDAT stream can be re-chunked this stream is
+                      * held in the struct IDAT members.  The chunk members, in
+                      * particular chunk_length (and therefore the length local)
+                      * refer to the output chunk.
+                      */
+                     while (idat->idat_index >= idat->idat_length)
+                     {
+                        /* Advance one chunk */
+                        struct IDAT_list *cur = idat->idat_cur;
+
+                        assert(idat->idat_index == idat->idat_length);
+                        assert(cur != NULL && cur->count > 0);
+
+                        /* NOTE: IDAT_list::count here, not IDAT_list::length */
+                        if (++(idat->idat_count) >= cur->count)
+                        {
+                           assert(idat->idat_count == cur->count);
+
+                           /* Move on to the next IDAT_list: */
+                           cur = cur->next;
+
+                           /* This is an internal error - read beyond the end of
+                            * the pre-calculated stream.
+                            */
+                           if (cur == NULL || cur->count == 0)
+                              stop(file, UNEXPECTED_ERROR_CODE,
+                                 "read beyond end of IDAT");
+
+                           idat->idat_count = 0;
+                           idat->idat_cur = cur;
+                        }
+
+                        idat->idat_index = 0;
+                        /* Zero length IDAT chunks are permitted, so the length
+                         * here may be 0.
+                         */
+                        idat->idat_length = cur->lengths[idat->idat_count];
+
+                        /* And skip 12 bytes to the next chunk data */
+                        skip_12(file);
+                     }
+
+                     /* The index is always that of the next byte, the rest of
+                      * the information is always the current IDAT chunk and the
+                      * current list.
+                      */
+                     ++(idat->idat_index);
+                  }
+
+                  /* Read the byte from the stream. */
+                  b = reread_byte(file);
+
+                  /* If the byte must be rewritten handle that here */
+                  if (chunk->rewrite_length > 0)
+                  {
+                     if (chunk->rewrite_offset > 0)
+                        --(chunk->rewrite_offset);
+
+                     else
+                     {
+                        b = chunk->rewrite_buffer[0];
+                        memmove(chunk->rewrite_buffer, chunk->rewrite_buffer+1,
+                           (sizeof chunk->rewrite_buffer)-
+                              (sizeof chunk->rewrite_buffer[0]));
+
+                        --(chunk->rewrite_length);
+                     }
+                  }
+
+                  chunk->write_crc = crc_one_byte(chunk->write_crc, b);
+                  break;
+
+               /* The CRC is written at:
+                *
+                *    chunk_write == chunk_length+8..chunk_length+11
+                *
+                * so 8 to 11.  The CRC is not (yet) conditioned.
+                */
+               case  8: b = chunk->write_crc >> 24; goto write_crc;
+               case  9: b = chunk->write_crc >> 16; goto write_crc;
+               case 10: b = chunk->write_crc >>  8; goto write_crc;
+               case 11:
+                  /* This must happen before the chunk_end below: */
+                  b = chunk->write_crc;
+
+                  if (file->global->verbose > 2)
+                  {
+                     fputs("   ", stderr);
+                     type_name(type, stderr);
+                     fprintf(stderr, " %lu 0x%.8x\n", (unsigned long)length,
+                        chunk->write_crc ^ 0xffffffff);
+                  }
+
+                  /* The IDAT stream is written without a call to read_chunk
+                   * until the end is reached.  rechunk_length() calculates the
+                   * length of the output chunks.  Control gets to this point at
+                   * the end of an *output* chunk - the length calculated by
+                   * rechunk_length.  If this corresponds to the end of the
+                   * input stream stop writing IDAT chunks, otherwise continue.
+                   */
+                  if (file->state == STATE_IDAT &&
+                     (file->idat->idat_index < file->idat->idat_length ||
+                      1+file->idat->idat_count < file->idat->idat_cur->count ||
+                      file->idat->idat_cur != file->idat->idat_list_tail))
+                  {
+                     /* Write another IDAT chunk.  Call rechunk_length to
+                      * calculate the length required.
+                      */
+                     length = chunk->chunk_length =
+                         rechunk_length(file->idat, 0/*end*/);
+                     assert(type == png_IDAT);
+                     file->write_count = 0; /* for the new chunk */
+                     --(file->write_count); /* fake out the increment below */
+                  }
+
+                  else
+                  {
+                     /* Entered at the end of a non-IDAT chunk and at the end of
+                      * the IDAT stream.  The rewrite should have been cleared.
+                      */
+                     if (chunk->rewrite_length > 0 || chunk->rewrite_offset > 0)
+                        stop(file, UNEXPECTED_ERROR_CODE, "pending rewrite");
+
+                     /* This is the last byte so reset chunk_read for the next
+                      * chunk and move the input file to the position after the
+                      * *next* chunk header if required.
+                      */
+                     file->read_count = 8;
+                     file_setpos(file, &file->data_pos);
+
+                     if (file->idat == NULL)
+                        chunk_end(&file->chunk);
+
+                     else
+                        IDAT_end(&file->idat);
+                  }
+
+               write_crc:
+                  b ^= 0xff; /* conditioning */
+                  break;
+            }
+            break;
+      }
+
+      /* Write one byte */
+      b &= 0xff;
+      *buffer++ = (png_byte)b;
+      --count;
+      write_byte(file, (png_byte)b); /* increments chunk_write */
+   }
+   while (count > 0);
+}
+
+/* Bundle the file and an uninitialized chunk and IDAT control structure
+ * together to allow implementation of the chunk/IDAT allocate routine.
+ */
+struct control
+{
+   struct file  file;
+   struct chunk chunk;
+   struct IDAT  idat;
+};
+
+static int
+control_end(struct control *control)
+{
+   return file_end(&control->file);
+}
+
+static struct file *
+get_control(png_const_structrp png_ptr)
+{
+   /* This just returns the (file*).  The chunk and idat control structures
+    * don't always exist.
+    */
+   struct control *control = voidcast(struct control*,
+      png_get_error_ptr(png_ptr));
+   return &control->file;
+}
+
+static void
+allocate(struct file *file, int allocate_idat)
+{
+   struct control *control = voidcast(struct control*, file->alloc_ptr);
+
+   if (allocate_idat)
+   {
+      assert(file->idat == NULL);
+      IDAT_init(&control->idat, file);
+   }
+
+   else /* chunk */
+   {
+      assert(file->chunk == NULL);
+      chunk_init(&control->chunk, file);
+   }
+}
+
+static int
+control_init(struct control *control, struct global *global,
+   const char *file_name, const char *out_name)
+   /* This wraps file_init(&control::file) and simply returns the result from
+    * file_init.
+    */
+{
+   return file_init(&control->file, global, file_name, out_name, control,
+      allocate);
+}
+
+static int
+read_png(struct control *control)
+   /* Read a PNG, return 0 on success else an error (status) code; a bit mask as
+    * defined for file::status_code as above.
+    */
+{
+   png_structp png_ptr;
+   png_infop info_ptr = NULL;
+   volatile int rc;
+
+   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, control,
+      error_handler, warning_handler);
+
+   if (png_ptr == NULL)
+   {
+      /* This is not really expected. */
+      log_error(&control->file, LIBPNG_ERROR_CODE, "OOM allocating png_struct");
+      control->file.status_code |= INTERNAL_ERROR;
+      return LIBPNG_ERROR_CODE;
+   }
+
+   rc = setjmp(control->file.jmpbuf);
+   if (rc == 0)
+   {
+#     ifdef PNG_SET_USER_LIMITS_SUPPORTED
+         /* Remove any limits on the size of PNG files that can be read,
+          * without this we may reject files based on built-in safety
+          * limits.
+          */
+         png_set_user_limits(png_ptr, 0x7fffffff, 0x7fffffff);
+         png_set_chunk_cache_max(png_ptr, 0);
+         png_set_chunk_malloc_max(png_ptr, 0);
+#     endif
+
+      png_set_read_fn(png_ptr, control, read_callback);
+
+      info_ptr = png_create_info_struct(png_ptr);
+      if (info_ptr == NULL)
+         png_error(png_ptr, "OOM allocating info structure");
+
+      if (control->file.global->verbose)
+         fprintf(stderr, " INFO\n");
+
+      png_read_info(png_ptr, info_ptr);
+
+      {
+        png_uint_32 height = png_get_image_height(png_ptr, info_ptr);
+        int passes = png_set_interlace_handling(png_ptr);
+        int pass;
+
+        png_start_read_image(png_ptr);
+
+        for (pass = 0; pass < passes; ++pass)
+        {
+           png_uint_32 y = height;
+
+           /* NOTE: this skips asking libpng to return either version of
+            * the image row, but libpng still reads the rows.
+            */
+           while (y-- > 0)
+              png_read_row(png_ptr, NULL, NULL);
+        }
+      }
+
+      if (control->file.global->verbose)
+         fprintf(stderr, " END\n");
+
+      /* Make sure to read to the end of the file: */
+      png_read_end(png_ptr, info_ptr);
+   }
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+   return rc;
+}
+
+static int
+one_file(struct global *global, const char *file_name, const char *out_name)
+{
+   int rc;
+   struct control control;
+
+   if (global->verbose)
+      fprintf(stderr, "FILE %s -> %s\n", file_name,
+         out_name ? out_name : "<none>");
+
+   /* Although control_init can return a failure code the structure is always
+    * initialized, so control_end can be used to accumulate any status codes.
+    */
+   rc = control_init(&control, global, file_name, out_name);
+
+   if (rc == 0)
+      rc = read_png(&control);
+
+   rc |= control_end(&control);
+
+   return rc;
+}
+
+static void
+usage(const char *prog)
+{
+   /* ANSI C-90 limits strings to 509 characters, so use a string array: */
+   size_t i;
+   static const char *usage_string[] = {
+"  Tests, optimizes and optionally fixes the zlib header in PNG files.",
+"  Optionally, when fixing, strips ancillary chunks from the file.",
+0,
+"OPTIONS",
+"  OPERATION",
+"      By default files are just checked for readability with a summary of the",
+"      of zlib issues founds for each compressed chunk and the IDAT stream in",
+"      the file.",
+"    --optimize (-o):",
+"      Find the smallest deflate window size for the compressed data.",
+"    --strip=[none|crc|unsafe|unused|transform|color|all]:",
+"        none (default):   Retain all chunks.",
+"        crc:    Remove chunks with a bad CRC.",
+"        unsafe: Remove chunks that may be unsafe to retain if the image data",
+"                is modified.  This is set automatically if --max is given but",
+"                may be cancelled by a later --strip=none.",
+"        unused: Remove chunks not used by libpng when decoding an image.",
+"                This retains any chunks that might be used by libpng image",
+"                transformations.",
+"        transform: unused+bKGD.",
+"        color:  transform+iCCP and cHRM.",
+"        all:    color+gAMA and sRGB.",
+"      Only ancillary chunks are ever removed.  In addition the tRNS and sBIT",
+"      chunks are never removed as they affect exact interpretation of the",
+"      image pixel values.  The following known chunks are treated specially",
+"      by the above options:",
+"        gAMA, sRGB [all]: These specify the gamma encoding used for the pixel",
+"            values.",
+"        cHRM, iCCP [color]: These specify how colors are encoded.  iCCP also",
+"            specifies the exact encoding of a pixel value; however, in",
+"            practice most programs will ignore it.",
+"        bKGD [transform]: This is used by libpng transforms."
+"    --max=<number>:",
+"      Use IDAT chunks sized <number>.  If no number is given the IDAT",
+"      chunks will be the maximum size permitted; 2^31-1 bytes.  If the option",
+"      is omitted the original chunk sizes will not be changed.  When the",
+"      option is given --strip=unsafe is set automatically. This may be",
+"      cancelled if you know that all unknown unsafe-to-copy chunks really are",
+"      safe to copy across an IDAT size change.  This is true of all chunks",
+"      that have ever been formally proposed as PNG extensions.",
+"  MESSAGES",
+"      By default the program only outputs summaries for each file.",
+"    --quiet (-q):",
+"      Do not output the summaries except for files that cannot be read. With",
+"      two --quiets these are not output either.",
+"    --errors (-e):",
+"      Output errors from libpng and the program (except too-far-back).",
+"    --warnings (-w):",
+"      Output warnings from libpng.",
+"  OUTPUT",
+"      By default nothing is written.",
+"    --out=<file>:",
+"      Write the optimized/corrected version of the next PNG to <file>.  This",
+"      overrides the following two options",
+"    --suffix=<suffix>:",
+"      Set --out=<name><suffix> for all following files unless overridden on",
+"      a per-file basis by explicit --out.",
+"    --prefix=<prefix>:",
+"      Set --out=<prefix><name> for all the following files unless overridden",
+"      on a per-file basis by explicit --out.",
+"      These two options can be used together to produce a suffix and prefix.",
+"  INTERNAL OPTIONS",
+#if 0 /*NYI*/
+#ifdef PNG_MAXIMUM_INFLATE_WINDOW
+"    --test:",
+"      Test the PNG_MAXIMUM_INFLATE_WINDOW option.  Setting this disables",
+"      output as this would produce a broken file.",
+#endif
+#endif
+0,
+"EXIT CODES",
+"  *** SUBJECT TO CHANGE ***",
+"  The program exit code is value in the range 0..127 holding a bit mask of",
+"  the following codes.  Notice that the results for each file are combined",
+"  together - check one file at a time to get a meaningful error code!",
+"    0x01: The zlib too-far-back error existed in at least one chunk.",
+"    0x02: At least one chunk had a CRC error.",
+"    0x04: A chunk length was incorrect.",
+"    0x08: The file was truncated.",
+"  Errors less than 16 are potentially recoverable, for a single file if the",
+"  exit code is less than 16 the file could be read (with corrections if a",
+"  non-zero code is returned).",
+"    0x10: The file could not be read, even with corrections.",
+"    0x20: The output file could not be written.",
+"    0x40: An unexpected, potentially internal, error occurred.",
+"  If the command line arguments are incorrect the program exits with exit",
+"  255.  Some older operating systems only support 7-bit exit codes, on those",
+"  systems it is suggested that this program is first tested by supplying",
+"  invalid arguments.",
+0,
+"DESCRIPTION",
+"  " PROGRAM_NAME ":",
+"  checks each PNG file on the command line for errors.  By default errors are",
+"  not output and the program just returns an exit code and prints a summary.",
+"  With the --quiet (-q) option the summaries are suppressed too and the",
+"  program only outputs unexpected errors (internal errors and file open",
+"  errors).",
+"  Various known problems in PNG files are fixed while the file is being read",
+"  The exit code says what problems were fixed.  In particular the zlib error:",
+0,
+"        \"invalid distance too far back\"",
+0,
+"  caused by an incorrect optimization of a zlib stream is fixed in any",
+"  compressed chunk in which it is encountered.  An integrity problem of the",
+"  PNG stream caused by a bug in libpng which wrote an incorrect chunk length",
+"  is also fixed.  Chunk CRC errors are automatically fixed up.",
+0,
+"  Setting one of the \"OUTPUT\" options causes the possibly modified file to",
+"  be written to a new file.",
+0,
+"  Notice that some PNG files with the zlib optimization problem can still be",
+"  read by libpng under some circumstances.  This program will still detect",
+"  and, if requested, correct the error.",
+0,
+"  The program will reliably process all files on the command line unless",
+"  either an invalid argument causes the usage message (this message) to be",
+"  produced or the program crashes.",
+0,
+"  The summary lines describe issues encountered with the zlib compressed",
+"  stream of a chunk.  They have the following format, which is SUBJECT TO",
+"  CHANGE in the future:",
+0,
+"     chunk reason comp-level p1 p2 p3 p4 file",
+0,
+"  p1 through p4 vary according to the 'reason'.  There are always 8 space",
+"  separated fields.  Reasons specific formats are:",
+0,
+"     chunk ERR status code read-errno write-errno message file",
+"     chunk SKP comp-level file-bits zlib-rc compressed message file",
+"     chunk ??? comp-level file-bits ok-bits compressed uncompress file",
+0,
+"  The various fields are",
+0,
+"$1 chunk:      The chunk type of a chunk in the file or 'HEAD' if a problem",
+"               is reported by libpng at the start of the IDAT stream.",
+"$2 reason:     One of:",
+"          CHK: A zlib header checksum was detected and fixed.",
+"          TFB: The zlib too far back error was detected and fixed.",
+"          OK : No errors were detected in the zlib stream and optimization",
+"               was not requested, or was not possible.",
+"          OPT: The zlib stream window bits value could be improved (and was).",
+"          SKP: The chunk was skipped because of a zlib issue (zlib-rc) with",
+"               explanation 'message'",
+"          ERR: The read of the file was aborted.  The parameters explain why.",
+"$3 status:     For 'ERR' the accumulated status code from 'EXIT CODES' above.",
+"               This is printed as a 2 digit hexadecimal value",
+"   comp-level: The recorded compression level (FLEVEL) of a zlib stream",
+"               expressed as a string {supfast,stdfast,default,maximum}",
+"$4 code:       The file exit code; where stop was called, as a fairly terse",
+"               string {warning,libpng,zlib,invalid,read,write,unexpected}.",
+"   file-bits:  The zlib window bits recorded in the file.",
+"$5 read-errno: A system errno value from a read translated by strerror(3).",
+"   zlib-rc:    A zlib return code as a string (see zlib.h).",
+"   ok-bits:    The smallest zlib window bits value that works.",
+"$6 write-errno:A system errno value from a write translated by strerror(3).",
+"   compressed: The count of compressed bytes in the zlib stream, when the",
+"               reason is 'SKP'; this is a count of the bytes read from the",
+"               stream when the fatal error was encountered.",
+"$7 message:    An error message (spaces replaced by _, as in all parameters),",
+"   uncompress: The count of bytes from uncompressing the zlib stream; this",
+"               may not be the same as the number of bytes in the image.",
+"$8 file:       The name of the file (this may contain spaces).",
+};
+
+   fprintf(stderr, "Usage: %s {[options] png-file}\n", prog);
+
+   for (i=0; i < (sizeof usage_string)/(sizeof usage_string[0]); ++i)
+   {
+      if (usage_string[i] != 0)
+         fputs(usage_string[i], stderr);
+
+      fputc('\n', stderr);
+   }
+
+   exit(255);
+}
+
+int
+main(int argc, const char **argv)
+{
+   char temp_name[FILENAME_MAX+1];
+   const char *  prog = *argv;
+   const char *  outfile = NULL;
+   const char *  suffix = NULL;
+   const char *  prefix = NULL;
+   int           done = 0; /* if at least one file is processed */
+   struct global global;
+
+   global_init(&global);
+
+   while (--argc > 0)
+   {
+      ++argv;
+
+      if (strcmp(*argv, "--debug") == 0)
+      {
+         /* To help debugging problems: */
+         global.errors = global.warnings = 1;
+         global.quiet = 0;
+         global.verbose = 7;
+      }
+
+      else if (strncmp(*argv, "--max=", 6) == 0)
+      {
+         global.idat_max = (png_uint_32)atol(6+*argv);
+
+         if (global.skip < SKIP_UNSAFE)
+            global.skip = SKIP_UNSAFE;
+      }
+
+      else if (strcmp(*argv, "--max") == 0)
+      {
+         global.idat_max = 0x7fffffff;
+
+         if (global.skip < SKIP_UNSAFE)
+            global.skip = SKIP_UNSAFE;
+      }
+
+      else if (strcmp(*argv, "--optimize") == 0 || strcmp(*argv, "-o") == 0)
+         global.optimize_zlib = 1;
+
+      else if (strncmp(*argv, "--out=", 6) == 0)
+         outfile = 6+*argv;
+
+      else if (strncmp(*argv, "--suffix=", 9) == 0)
+         suffix = 9+*argv;
+
+      else if (strncmp(*argv, "--prefix=", 9) == 0)
+         prefix = 9+*argv;
+
+      else if (strcmp(*argv, "--strip=none") == 0)
+         global.skip = SKIP_NONE;
+
+      else if (strcmp(*argv, "--strip=crc") == 0)
+         global.skip = SKIP_BAD_CRC;
+
+      else if (strcmp(*argv, "--strip=unsafe") == 0)
+         global.skip = SKIP_UNSAFE;
+
+      else if (strcmp(*argv, "--strip=unused") == 0)
+         global.skip = SKIP_UNUSED;
+
+      else if (strcmp(*argv, "--strip=transform") == 0)
+         global.skip = SKIP_TRANSFORM;
+
+      else if (strcmp(*argv, "--strip=color") == 0)
+         global.skip = SKIP_COLOR;
+
+      else if (strcmp(*argv, "--strip=all") == 0)
+         global.skip = SKIP_ALL;
+
+      else if (strcmp(*argv, "--errors") == 0 || strcmp(*argv, "-e") == 0)
+         global.errors = 1;
+
+      else if (strcmp(*argv, "--warnings") == 0 || strcmp(*argv, "-w") == 0)
+         global.warnings = 1;
+
+      else if (strcmp(*argv, "--quiet") == 0 || strcmp(*argv, "-q") == 0)
+      {
+         if (global.quiet)
+            global.quiet = 2;
+
+         else
+            global.quiet = 1;
+      }
+
+      else if (strcmp(*argv, "--verbose") == 0 || strcmp(*argv, "-v") == 0)
+         ++global.verbose;
+
+#if 0
+      /* NYI */
+#     ifdef PNG_MAXIMUM_INFLATE_WINDOW
+         else if (strcmp(*argv, "--test") == 0)
+            ++set_option;
+#     endif
+#endif
+
+      else if ((*argv)[0] == '-')
+         usage(prog);
+
+      else
+      {
+         size_t outlen = strlen(*argv);
+
+         if (outlen > FILENAME_MAX)
+         {
+            fprintf(stderr, "%s: output file name too long: %s%s%s\n",
+               prog, prefix, *argv, suffix ? suffix : "");
+            global.status_code |= WRITE_ERROR;
+            continue;
+         }
+
+         if (outfile == NULL) /* else this takes precedence */
+         {
+            /* Consider the prefix/suffix options */
+            if (prefix != NULL)
+            {
+               size_t prefixlen = strlen(prefix);
+
+               if (prefixlen+outlen > FILENAME_MAX)
+               {
+                  fprintf(stderr, "%s: output file name too long: %s%s%s\n",
+                     prog, prefix, *argv, suffix ? suffix : "");
+                  global.status_code |= WRITE_ERROR;
+                  continue;
+               }
+
+               memcpy(temp_name, prefix, prefixlen);
+               memcpy(temp_name+prefixlen, *argv, outlen);
+               outlen += prefixlen;
+               outfile = temp_name;
+            }
+
+            else if (suffix != NULL)
+               memcpy(temp_name, *argv, outlen);
+
+            temp_name[outlen] = 0;
+
+            if (suffix != NULL)
+            {
+               size_t suffixlen = strlen(suffix);
+
+               if (outlen+suffixlen > FILENAME_MAX)
+               {
+                  fprintf(stderr, "%s: output file name too long: %s%s\n",
+                     prog, *argv, suffix);
+                  global.status_code |= WRITE_ERROR;
+                  continue;
+               }
+
+               memcpy(temp_name+outlen, suffix, suffixlen);
+               outlen += suffixlen;
+               temp_name[outlen] = 0;
+               outfile = temp_name;
+            }
+         }
+
+         (void)one_file(&global, *argv, outfile);
+         ++done;
+         outfile = NULL;
+      }
+   }
+
+   if (!done)
+      usage(prog);
+
+   return global_end(&global);
+}
+
+#else /* ZLIB_VERNUM < 0x1240 */
+int
+main(void)
+{
+   fprintf(stderr,
+      "pngfix needs libpng with a zlib >=1.2.4 (not 0x%x)\n",
+      ZLIB_VERNUM);
+   return 77;
+}
+#endif /* ZLIB_VERNUM */
+
+#else /* No read support */
+
+int
+main(void)
+{
+   fprintf(stderr, "pngfix does not work without read deinterlace support\n");
+   return 77;
+}
+#endif /* PNG_READ_SUPPORTED && PNG_EASY_ACCESS_SUPPORTED */
+#else /* No setjmp support */
+int
+main(void)
+{
+   fprintf(stderr, "pngfix does not work without setjmp support\n");
+   return 77;
+}
+#endif /* PNG_SETJMP_SUPPORTED */
+/* vi: set textwidth=80 shiftwidth=3 softtabstop=-1 expandtab: */
Index: /trunk/src/libs/libpng-1.6.45/contrib/tools/sRGB.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/tools/sRGB.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/tools/sRGB.h	(revision 107811)
@@ -0,0 +1,46 @@
+/* sRGB.h
+ *
+ * COPYRIGHT: Written by John Cunningham Bowler, 2013.
+ * To the extent possible under law, the author has waived all copyright and
+ * related or neighboring rights to this work.  This work is published from:
+ * United States.
+ *
+ * Utility file; not actually a header, this contains definitions of sRGB
+ * calculation functions for inclusion in those test programs that need them.
+ *
+ * All routines take and return a floating point value in the range
+ * 0 to 1.0, doing a calculation according to the sRGB specification
+ * (in fact the source of the numbers is the wikipedia article at
+ * https://en.wikipedia.org/wiki/SRGB).
+ */
+
+static double
+sRGB_from_linear(double l)
+{
+   if (l <= 0.0031308)
+      l *= 12.92;
+
+   else
+      l = 1.055 * pow(l, 1/2.4) - 0.055;
+
+   return l;
+}
+
+static double
+linear_from_sRGB(double s)
+{
+   if (s <= 0.04045)
+      return s / 12.92;
+
+   else
+      return pow((s+0.055)/1.055, 2.4);
+}
+
+static double
+YfromRGB(double r, double g, double b)
+{
+   /* Use the sRGB (rounded) coefficients for Rlinear, Glinear, Blinear to get
+    * the CIE Y value (also linear).
+    */
+   return 0.2126 * r + 0.7152 * g + 0.0722 * b;
+}
Index: /trunk/src/libs/libpng-1.6.45/contrib/visupng/PngFile.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/visupng/PngFile.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/visupng/PngFile.c	(revision 107811)
@@ -0,0 +1,454 @@
+/*-------------------------------------
+ *  PNGFILE.C -- Image File Functions
+ *-------------------------------------
+ *
+ * Copyright 2000,2017 Willem van Schaik.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include <windows.h>
+#include <commdlg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <zlib.h>
+
+#include "png.h"
+#include "pngfile.h"
+#include "cexcept.h"
+
+define_exception_type(const char *);
+extern struct exception_context the_exception_context[1];
+struct exception_context the_exception_context[1];
+png_const_charp msg;
+
+static OPENFILENAME ofn;
+
+static png_structp png_ptr = NULL;
+static png_infop info_ptr = NULL;
+
+
+/* cexcept interface */
+
+static void
+png_cexcept_error(png_structp png_ptr, png_const_charp msg)
+{
+   if(png_ptr)
+     ;
+#ifdef PNG_CONSOLE_IO_SUPPORTED
+   fprintf(stderr, "libpng error: %s\n", msg);
+#endif
+   {
+      Throw msg;
+   }
+}
+
+/* Windows open-file functions */
+
+void PngFileInitialize (HWND hwnd)
+{
+    static TCHAR szFilter[] = TEXT ("PNG Files (*.PNG)\0*.png\0")
+        TEXT ("All Files (*.*)\0*.*\0\0");
+
+    ofn.lStructSize       = sizeof (OPENFILENAME);
+    ofn.hwndOwner         = hwnd;
+    ofn.hInstance         = NULL;
+    ofn.lpstrFilter       = szFilter;
+    ofn.lpstrCustomFilter = NULL;
+    ofn.nMaxCustFilter    = 0;
+    ofn.nFilterIndex      = 0;
+    ofn.lpstrFile         = NULL;          /* Set in Open and Close functions */
+    ofn.nMaxFile          = MAX_PATH;
+    ofn.lpstrFileTitle    = NULL;          /* Set in Open and Close functions */
+    ofn.nMaxFileTitle     = MAX_PATH;
+    ofn.lpstrInitialDir   = NULL;
+    ofn.lpstrTitle        = NULL;
+    ofn.Flags             = 0;             /* Set in Open and Close functions */
+    ofn.nFileOffset       = 0;
+    ofn.nFileExtension    = 0;
+    ofn.lpstrDefExt       = TEXT ("png");
+    ofn.lCustData         = 0;
+    ofn.lpfnHook          = NULL;
+    ofn.lpTemplateName    = NULL;
+}
+
+BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName)
+{
+    ofn.hwndOwner         = hwnd;
+    ofn.lpstrFile         = pstrFileName;
+    ofn.lpstrFileTitle    = pstrTitleName;
+    ofn.Flags             = OFN_HIDEREADONLY;
+
+    return GetOpenFileName (&ofn);
+}
+
+BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName)
+{
+    ofn.hwndOwner         = hwnd;
+    ofn.lpstrFile         = pstrFileName;
+    ofn.lpstrFileTitle    = pstrTitleName;
+    ofn.Flags             = OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT;
+
+    return GetSaveFileName (&ofn);
+}
+
+/* PNG image handler functions */
+
+BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
+                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor)
+{
+    static FILE        *pfFile;
+    png_byte            pbSig[8];
+    int                 iBitDepth;
+    int                 iColorType;
+    double              dGamma;
+    png_color_16       *pBackground;
+    png_uint_32         ulChannels;
+    png_uint_32         ulRowBytes;
+    png_byte           *pbImageData = *ppbImageData;
+    static png_byte   **ppbRowPointers = NULL;
+    int                 i;
+
+    /* open the PNG input file */
+
+    if (!pstrFileName)
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    if (!(pfFile = fopen(pstrFileName, "rb")))
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    /* first check the eight byte PNG signature */
+
+    fread(pbSig, 1, 8, pfFile);
+    if (png_sig_cmp(pbSig, 0, 8))
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    /* create the two png(-info) structures */
+
+    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
+      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
+    if (!png_ptr)
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr)
+    {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+
+    Try
+    {
+
+        /* initialize the png structure */
+
+#ifdef PNG_STDIO_SUPPORTED
+        png_init_io(png_ptr, pfFile);
+#else
+        png_set_read_fn(png_ptr, (png_voidp)pfFile, png_read_data);
+#endif
+
+        png_set_sig_bytes(png_ptr, 8);
+
+        /* read all PNG info up to image data */
+
+        png_read_info(png_ptr, info_ptr);
+
+        /* get width, height, bit-depth and color-type */
+
+        png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
+            &iColorType, NULL, NULL, NULL);
+
+        /* expand images of all color-type and bit-depth to 3x8-bit RGB */
+        /* let the library process alpha, transparency, background, etc. */
+
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+    if (iBitDepth == 16)
+#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+        png_set_scale_16(png_ptr);
+#  else
+        png_set_strip_16(png_ptr);
+#  endif
+#endif
+        if (iColorType == PNG_COLOR_TYPE_PALETTE)
+            png_set_expand(png_ptr);
+        if (iBitDepth < 8)
+            png_set_expand(png_ptr);
+        if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+            png_set_expand(png_ptr);
+        if (iColorType == PNG_COLOR_TYPE_GRAY ||
+            iColorType == PNG_COLOR_TYPE_GRAY_ALPHA)
+            png_set_gray_to_rgb(png_ptr);
+
+        /* set the background color to draw transparent and alpha images over */
+        if (png_get_bKGD(png_ptr, info_ptr, &pBackground))
+        {
+            png_set_background(png_ptr, pBackground, PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+            pBkgColor->red   = (byte) pBackground->red;
+            pBkgColor->green = (byte) pBackground->green;
+            pBkgColor->blue  = (byte) pBackground->blue;
+        }
+        else
+        {
+            pBkgColor = NULL;
+        }
+
+        /* if required set gamma conversion */
+        if (png_get_gAMA(png_ptr, info_ptr, &dGamma))
+            png_set_gamma(png_ptr, (double) 2.2, dGamma);
+
+        /* after the transformations are registered, update info_ptr data */
+
+        png_read_update_info(png_ptr, info_ptr);
+
+        /* get again width, height and the new bit-depth and color-type */
+
+        png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
+            &iColorType, NULL, NULL, NULL);
+
+
+        /* row_bytes is the width x number of channels */
+
+        ulRowBytes = png_get_rowbytes(png_ptr, info_ptr);
+        ulChannels = png_get_channels(png_ptr, info_ptr);
+
+        *piChannels = ulChannels;
+
+        /* now we can allocate memory to store the image */
+
+        if (pbImageData)
+        {
+            free (pbImageData);
+            pbImageData = NULL;
+        }
+        if ((*piHeight) > ((size_t)(-1))/ulRowBytes) {
+        {
+            png_error(png_ptr, "Visual PNG: image is too big");
+        }
+        if ((pbImageData = (png_byte *) malloc(ulRowBytes * (*piHeight)
+                            * sizeof(png_byte))) == NULL)
+        {
+            png_error(png_ptr, "Visual PNG: out of memory");
+        }
+        *ppbImageData = pbImageData;
+
+        /* and allocate memory for an array of row-pointers */
+
+        if ((ppbRowPointers = (png_bytepp) malloc((*piHeight)
+                            * sizeof(png_bytep))) == NULL)
+        {
+            png_error(png_ptr, "Visual PNG: out of memory");
+        }
+
+        /* set the individual row-pointers to point at the correct offsets */
+
+        for (i = 0; i < (*piHeight); i++)
+            ppbRowPointers[i] = pbImageData + i * ulRowBytes;
+
+        /* now we can go ahead and just read the whole image */
+
+        png_read_image(png_ptr, ppbRowPointers);
+
+        /* read the additional chunks in the PNG file (not really needed) */
+
+        png_read_end(png_ptr, NULL);
+
+        /* and we're done */
+
+        free (ppbRowPointers);
+        ppbRowPointers = NULL;
+
+        /* yepp, done */
+    }
+
+    Catch (msg)
+    {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+        *ppbImageData = pbImageData = NULL;
+
+        if(ppbRowPointers)
+            free (ppbRowPointers);
+
+        fclose(pfFile);
+
+        return FALSE;
+    }
+
+    fclose (pfFile);
+
+    return TRUE;
+}
+
+
+BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
+                   int iWidth, int iHeight, png_color bkgColor)
+{
+    const int           ciBitDepth = 8;
+    const int           ciChannels = 3;
+
+    static FILE        *pfFile;
+    png_uint_32         ulRowBytes;
+    static png_byte   **ppbRowPointers = NULL;
+    int                 i;
+
+    /* open the PNG output file */
+
+    if (!pstrFileName)
+        return FALSE;
+
+    if (!(pfFile = fopen(pstrFileName, "wb")))
+        return FALSE;
+
+    /* prepare the standard PNG structures */
+
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
+      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
+    if (!png_ptr)
+    {
+        fclose(pfFile);
+        return FALSE;
+    }
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        fclose(pfFile);
+        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+        return FALSE;
+    }
+
+    Try
+    {
+        /* initialize the png structure */
+
+#ifdef PNG_STDIO_SUPPORTED
+        png_init_io(png_ptr, pfFile);
+#else
+        png_set_write_fn(png_ptr, (png_voidp)pfFile, png_write_data, png_flush);
+#endif
+
+        /* we're going to write a very simple 3x8-bit RGB image */
+
+        png_set_IHDR(png_ptr, info_ptr, iWidth, iHeight, ciBitDepth,
+            PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
+            PNG_FILTER_TYPE_BASE);
+
+        /* write the file header information */
+
+        png_write_info(png_ptr, info_ptr);
+
+        /* swap the BGR pixels in the DiData structure to RGB */
+
+        png_set_bgr(png_ptr);
+
+        /* row_bytes is the width x number of channels */
+
+        ulRowBytes = iWidth * ciChannels;
+
+        /* we can allocate memory for an array of row-pointers */
+
+        if ((ppbRowPointers = (png_bytepp) malloc(iHeight * sizeof(png_bytep))) == NULL)
+            Throw "Visualpng: Out of memory";
+
+        /* set the individual row-pointers to point at the correct offsets */
+
+        for (i = 0; i < iHeight; i++)
+            ppbRowPointers[i] = pDiData + i * (((ulRowBytes + 3) >> 2) << 2);
+
+        /* write out the entire image data in one call */
+
+        png_write_image (png_ptr, ppbRowPointers);
+
+        /* write the additional chunks to the PNG file (not really needed) */
+
+        png_write_end(png_ptr, info_ptr);
+
+        /* and we're done */
+
+        free (ppbRowPointers);
+        ppbRowPointers = NULL;
+
+        /* clean up after the write, and free any memory allocated */
+
+        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+
+        /* yepp, done */
+    }
+
+    Catch (msg)
+    {
+        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+
+        if(ppbRowPointers)
+            free (ppbRowPointers);
+
+        fclose(pfFile);
+
+        return FALSE;
+    }
+
+    fclose (pfFile);
+
+    return TRUE;
+}
+
+#ifndef PNG_STDIO_SUPPORTED
+
+static void
+png_read_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check;
+
+   /* fread() returns 0 on error, so it is OK to store this in a size_t
+    * instead of an int, which is what fread() actually returns.
+    */
+   check = fread(data, 1, length, (FILE *)png_ptr->io_ptr);
+
+   if (check != length)
+   {
+      png_error(png_ptr, "Read Error");
+   }
+}
+
+static void
+png_write_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   png_uint_32 check;
+
+   check = fwrite(data, 1, length, (FILE *)(png_ptr->io_ptr));
+   if (check != length)
+   {
+      png_error(png_ptr, "Write Error");
+   }
+}
+
+static void
+png_flush(png_structp png_ptr)
+{
+   FILE *io_ptr;
+   io_ptr = (FILE *)CVT_PTR((png_ptr->io_ptr));
+   if (io_ptr != NULL)
+      fflush(io_ptr);
+}
+
+#endif
+
+/*-----------------
+ *  end of source
+ *-----------------
+ */
Index: /trunk/src/libs/libpng-1.6.45/contrib/visupng/PngFile.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/visupng/PngFile.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/visupng/PngFile.h	(revision 107811)
@@ -0,0 +1,30 @@
+/*------------------------------------------*/
+/*  PNGFILE.H -- Header File for pngfile.c*/
+/*------------------------------------------*/
+
+/* Copyright 2000, Willem van Schaik.*/
+
+/* This code is released under the libpng license.*/
+/* For conditions of distribution and use, see the disclaimer*/
+/* and license in png.h*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <windows.h>
+
+void PngFileInitialize (HWND hwnd) ;
+BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;
+BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;
+
+BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
+                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor);
+BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
+                   int iWidth, int iHeight, png_color BkgColor);
+
+#ifndef PNG_STDIO_SUPPORTED
+static void png_read_data(png_structp png_ptr, png_bytep data, size_t length);
+static void png_write_data(png_structp png_ptr, png_bytep data, size_t length);
+static void png_flush(png_structp png_ptr);
+#endif
+
Index: /trunk/src/libs/libpng-1.6.45/contrib/visupng/README.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/visupng/README.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/visupng/README.txt	(revision 107811)
@@ -0,0 +1,61 @@
+Microsoft Developer Studio Build File, Format Version 6.00 for VisualPng
+------------------------------------------------------------------------
+
+Copyright 2000, Willem van Schaik.
+
+This code is released under the libpng license.
+For conditions of distribution and use, see the disclaimer
+and license in png.h
+
+As a PNG .dll demo VisualPng is finished. More features would only hinder
+the program's objective. However, further extensions (like support for other
+graphics formats) are in development. To get these, or for pre-compiled
+binaries, go to "http://www.schaik.com/png/visualpng.html".
+
+------------------------------------------------------------------------
+
+Assumes that
+
+   libpng DLLs and LIBs are in ..\..\projects\msvc\win32\libpng
+   zlib DLLs and LIBs are in   ..\..\projects\msvc\win32\zlib
+   libpng header files are in  ..\..\..\libpng
+   zlib header files are in    ..\..\..\zlib
+   the pngsuite images are in  ..\pngsuite
+
+To build:
+
+1) On the main menu Select "Build|Set Active configuration".
+   Choose the configuration that corresponds to the library you want to test.
+   This library must have been built using the libpng MS project located in
+   the "..\..\mscv" subdirectory.
+
+2) Select "Build|Clean"
+
+3) Select "Build|Rebuild All"
+
+4) After compiling and linking VisualPng will be started to view an image
+   from the PngSuite directory.  Press Ctrl-N (and Ctrl-V) for other images.
+
+
+To install:
+
+When distributing VisualPng (or a further development) the following options
+are available:
+
+1) Build the program with the configuration "Win32 LIB" and you only need to
+   include the executable from the ./lib directory in your distribution.
+
+2) Build the program with the configuration "Win32 DLL" and you need to put
+   in your distribution the executable from the ./dll directory and the dll's
+   libpng1.dll, zlib.dll and msvcrt.dll.  These need to be in the user's PATH.
+
+
+Willem van Schaik
+Calgary, June 6th 2000
+
+P.S. VisualPng was written based on preliminary work of:
+
+    - Simon-Pierre Cadieux
+    - Glenn Randers-Pehrson
+    - Greg Roelofs
+
Index: /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.c	(revision 107811)
@@ -0,0 +1,978 @@
+/*------------------------------------
+ *  VisualPng.C -- Shows a PNG image
+ *------------------------------------
+ *
+ * Copyright 2000,2017 Willem van Schaik.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* switches */
+
+/* defines */
+
+#define PROGNAME  "VisualPng"
+#define LONGNAME  "Win32 Viewer for PNG-files"
+#define VERSION   "1.0 of 2000 June 07"
+
+/* constants */
+
+#define MARGIN 8
+
+/* standard includes */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <windows.h>
+#include <zlib.h>
+
+/* application includes */
+
+#include "png.h"
+#include "pngfile.h"
+#include "resource.h"
+
+/* macros */
+
+/* function prototypes */
+
+LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
+BOOL    CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ;
+
+BOOL CenterAbout (HWND hwndChild, HWND hwndParent);
+
+BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
+        int *pFileIndex);
+
+BOOL SearchPngList (TCHAR *pFileList, int FileCount, int *pFileIndex,
+        PTSTR pstrPrevName, PTSTR pstrNextName);
+
+BOOL LoadImageFile(HWND hwnd, PTSTR pstrPathName,
+        png_byte **ppbImage, int *pxImgSize, int *pyImgSize, int *piChannels,
+        png_color *pBkgColor);
+
+BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
+        BYTE **ppDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched);
+
+BOOL InitBitmap (
+        BYTE *pDiData, int cxWinSize, int cyWinSize);
+
+BOOL FillBitmap (
+        BYTE *pDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched);
+
+/* a few global variables */
+
+static char *szProgName = PROGNAME;
+static char *szAppName = LONGNAME;
+static char *szIconName = PROGNAME;
+static char szCmdFileName [MAX_PATH];
+
+/* MAIN routine */
+
+int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
+                    PSTR szCmdLine, int iCmdShow)
+{
+    HACCEL   hAccel;
+    HWND     hwnd;
+    MSG      msg;
+    WNDCLASS wndclass;
+    int ixBorders, iyBorders;
+
+    wndclass.style         = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc   = WndProc;
+    wndclass.cbClsExtra    = 0;
+    wndclass.cbWndExtra    = 0;
+    wndclass.hInstance     = hInstance;
+    wndclass.hIcon         = LoadIcon (hInstance, szIconName) ;
+    wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW);
+    wndclass.hbrBackground = NULL; /* (HBRUSH) GetStockObject (GRAY_BRUSH); */
+    wndclass.lpszMenuName  = szProgName;
+    wndclass.lpszClassName = szProgName;
+
+    if (!RegisterClass (&wndclass))
+    {
+        MessageBox (NULL, TEXT ("Error: this program requires Windows NT!"),
+            szProgName, MB_ICONERROR);
+        return 0;
+    }
+
+    /* if filename given on command line, store it */
+    if ((szCmdLine != NULL) && (*szCmdLine != '\0'))
+        if (szCmdLine[0] == '"')
+            strncpy (szCmdFileName, szCmdLine + 1, strlen(szCmdLine) - 2);
+        else
+            strcpy (szCmdFileName, szCmdLine);
+    else
+        strcpy (szCmdFileName, "");
+
+    /* calculate size of window-borders */
+    ixBorders = 2 * (GetSystemMetrics (SM_CXBORDER) +
+                     GetSystemMetrics (SM_CXDLGFRAME));
+    iyBorders = 2 * (GetSystemMetrics (SM_CYBORDER) +
+                     GetSystemMetrics (SM_CYDLGFRAME)) +
+                     GetSystemMetrics (SM_CYCAPTION) +
+                     GetSystemMetrics (SM_CYMENUSIZE) +
+                     1; /* WvS: don't ask me why?  */
+
+    hwnd = CreateWindow (szProgName, szAppName,
+        WS_OVERLAPPEDWINDOW,
+        CW_USEDEFAULT, CW_USEDEFAULT,
+        512 + 2 * MARGIN + ixBorders, 384 + 2 * MARGIN + iyBorders,
+/*      CW_USEDEFAULT, CW_USEDEFAULT, */
+        NULL, NULL, hInstance, NULL);
+
+    ShowWindow (hwnd, iCmdShow);
+    UpdateWindow (hwnd);
+
+    hAccel = LoadAccelerators (hInstance, szProgName);
+
+    while (GetMessage (&msg, NULL, 0, 0))
+    {
+        if (!TranslateAccelerator (hwnd, hAccel, &msg))
+        {
+            TranslateMessage (&msg);
+            DispatchMessage (&msg);
+        }
+    }
+    return msg.wParam;
+}
+
+LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,
+        LPARAM lParam)
+{
+    static HINSTANCE          hInstance ;
+    static HDC                hdc;
+    static PAINTSTRUCT        ps;
+    static HMENU              hMenu;
+
+    static BITMAPFILEHEADER  *pbmfh;
+    static BITMAPINFOHEADER  *pbmih;
+    static BYTE              *pbImage;
+    static int                cxWinSize, cyWinSize;
+    static int                cxImgSize, cyImgSize;
+    static int                cImgChannels;
+    static png_color          bkgColor = {127, 127, 127};
+
+    static BOOL               bStretched = TRUE;
+
+    static BYTE              *pDib = NULL;
+    static BYTE              *pDiData = NULL;
+
+    static TCHAR              szImgPathName [MAX_PATH];
+    static TCHAR              szTitleName [MAX_PATH];
+
+    static TCHAR             *pPngFileList = NULL;
+    static int                iPngFileCount;
+    static int                iPngFileIndex;
+
+    BOOL                      bOk;
+
+    switch (message)
+    {
+    case WM_CREATE:
+        hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;
+        PngFileInitialize (hwnd);
+
+        strcpy (szImgPathName, "");
+
+        /* in case we process file given on command-line */
+
+        if (szCmdFileName[0] != '\0')
+        {
+            strcpy (szImgPathName, szCmdFileName);
+
+            /* read the other png-files in the directory for later */
+            /* next/previous commands */
+
+            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
+                          &iPngFileIndex);
+
+            /* load the image from file */
+
+            if (!LoadImageFile (hwnd, szImgPathName,
+                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
+                return 0;
+
+            /* invalidate the client area for later update */
+
+            InvalidateRect (hwnd, NULL, TRUE);
+
+            /* display the PNG into the DIBitmap */
+
+            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+        }
+
+        return 0;
+
+    case WM_SIZE:
+        cxWinSize = LOWORD (lParam);
+        cyWinSize = HIWORD (lParam);
+
+        /* invalidate the client area for later update */
+
+        InvalidateRect (hwnd, NULL, TRUE);
+
+        /* display the PNG into the DIBitmap */
+
+        DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+            pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+
+        return 0;
+
+    case WM_INITMENUPOPUP:
+        hMenu = GetMenu (hwnd);
+
+        if (pbImage)
+            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_ENABLED);
+        else
+            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_GRAYED);
+
+        return 0;
+
+    case WM_COMMAND:
+        hMenu = GetMenu (hwnd);
+
+        switch (LOWORD (wParam))
+        {
+        case IDM_FILE_OPEN:
+
+            /* show the File Open dialog box */
+
+            if (!PngFileOpenDlg (hwnd, szImgPathName, szTitleName))
+                return 0;
+
+            /* read the other png-files in the directory for later */
+            /* next/previous commands */
+
+            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
+                          &iPngFileIndex);
+
+            /* load the image from file */
+
+            if (!LoadImageFile (hwnd, szImgPathName,
+                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
+                return 0;
+
+            /* invalidate the client area for later update */
+
+            InvalidateRect (hwnd, NULL, TRUE);
+
+            /* display the PNG into the DIBitmap */
+
+            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+
+            return 0;
+
+        case IDM_FILE_SAVE:
+
+            /* show the File Save dialog box */
+
+            if (!PngFileSaveDlg (hwnd, szImgPathName, szTitleName))
+                return 0;
+
+            /* save the PNG to a disk file */
+
+            SetCursor (LoadCursor (NULL, IDC_WAIT));
+            ShowCursor (TRUE);
+
+            bOk = PngSaveImage (szImgPathName, pDiData, cxWinSize, cyWinSize,
+                  bkgColor);
+
+            ShowCursor (FALSE);
+            SetCursor (LoadCursor (NULL, IDC_ARROW));
+
+            if (!bOk)
+                MessageBox (hwnd, TEXT ("Error in saving the PNG image"),
+                szProgName, MB_ICONEXCLAMATION | MB_OK);
+            return 0;
+
+        case IDM_FILE_NEXT:
+
+            /* read next entry in the directory */
+
+            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
+                NULL, szImgPathName))
+            {
+                if (strcmp (szImgPathName, "") == 0)
+                    return 0;
+
+                /* load the image from file */
+
+                if (!LoadImageFile (hwnd, szImgPathName, &pbImage,
+                        &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
+                    return 0;
+
+                /* invalidate the client area for later update */
+
+                InvalidateRect (hwnd, NULL, TRUE);
+
+                /* display the PNG into the DIBitmap */
+
+                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+            }
+
+            return 0;
+
+        case IDM_FILE_PREVIOUS:
+
+            /* read previous entry in the directory */
+
+            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
+                szImgPathName, NULL))
+            {
+
+                if (strcmp (szImgPathName, "") == 0)
+                    return 0;
+
+                /* load the image from file */
+
+                if (!LoadImageFile (hwnd, szImgPathName, &pbImage, &cxImgSize,
+                    &cyImgSize, &cImgChannels, &bkgColor))
+                    return 0;
+
+                /* invalidate the client area for later update */
+
+                InvalidateRect (hwnd, NULL, TRUE);
+
+                /* display the PNG into the DIBitmap */
+
+                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+            }
+
+            return 0;
+
+        case IDM_FILE_EXIT:
+
+            /* more cleanup needed... */
+
+            /* free image buffer */
+
+            if (pDib != NULL)
+            {
+                free (pDib);
+                pDib = NULL;
+            }
+
+            /* free file-list */
+
+            if (pPngFileList != NULL)
+            {
+                free (pPngFileList);
+                pPngFileList = NULL;
+            }
+
+            /* let's go ... */
+
+            exit (0);
+
+            return 0;
+
+        case IDM_OPTIONS_STRETCH:
+            bStretched = !bStretched;
+            if (bStretched)
+                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_CHECKED);
+            else
+                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_UNCHECKED);
+
+            /* invalidate the client area for later update */
+
+            InvalidateRect (hwnd, NULL, TRUE);
+
+            /* display the PNG into the DIBitmap */
+
+            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+
+            return 0;
+
+        case IDM_HELP_ABOUT:
+            DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc) ;
+            return 0;
+
+        } /* end switch */
+
+        break;
+
+    case WM_PAINT:
+        hdc = BeginPaint (hwnd, &ps);
+
+        if (pDib)
+            SetDIBitsToDevice (hdc, 0, 0, cxWinSize, cyWinSize, 0, 0,
+                0, cyWinSize, pDiData, (BITMAPINFO *) pDib, DIB_RGB_COLORS);
+
+        EndPaint (hwnd, &ps);
+        return 0;
+
+    case WM_DESTROY:
+        if (pbmfh)
+        {
+            free (pbmfh);
+            pbmfh = NULL;
+        }
+
+        PostQuitMessage (0);
+        return 0;
+    }
+
+    return DefWindowProc (hwnd, message, wParam, lParam);
+}
+
+BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message,
+                            WPARAM wParam, LPARAM lParam)
+{
+     switch (message)
+     {
+     case WM_INITDIALOG :
+          ShowWindow (hDlg, SW_HIDE);
+          CenterAbout (hDlg, GetWindow (hDlg, GW_OWNER));
+          ShowWindow (hDlg, SW_SHOW);
+          return TRUE ;
+
+     case WM_COMMAND :
+          switch (LOWORD (wParam))
+          {
+          case IDOK :
+          case IDCANCEL :
+               EndDialog (hDlg, 0) ;
+               return TRUE ;
+          }
+          break ;
+     }
+     return FALSE ;
+}
+
+/*---------------
+ *  CenterAbout
+ *---------------
+ */
+BOOL CenterAbout (HWND hwndChild, HWND hwndParent)
+{
+   RECT    rChild, rParent, rWorkArea;
+   int     wChild, hChild, wParent, hParent;
+   int     xNew, yNew;
+   BOOL  bResult;
+
+   /* Get the Height and Width of the child window */
+   GetWindowRect (hwndChild, &rChild);
+   wChild = rChild.right - rChild.left;
+   hChild = rChild.bottom - rChild.top;
+
+   /* Get the Height and Width of the parent window */
+   GetWindowRect (hwndParent, &rParent);
+   wParent = rParent.right - rParent.left;
+   hParent = rParent.bottom - rParent.top;
+
+   /* Get the limits of the 'workarea' */
+   bResult = SystemParametersInfo(
+      SPI_GETWORKAREA,  /* system parameter to query or set */
+      sizeof(RECT),
+      &rWorkArea,
+      0);
+   if (!bResult) {
+      rWorkArea.left = rWorkArea.top = 0;
+      rWorkArea.right = GetSystemMetrics(SM_CXSCREEN);
+      rWorkArea.bottom = GetSystemMetrics(SM_CYSCREEN);
+   }
+
+   /* Calculate new X position, then adjust for workarea */
+   xNew = rParent.left + ((wParent - wChild) /2);
+   if (xNew < rWorkArea.left) {
+      xNew = rWorkArea.left;
+   } else if ((xNew+wChild) > rWorkArea.right) {
+      xNew = rWorkArea.right - wChild;
+   }
+
+   /* Calculate new Y position, then adjust for workarea */
+   yNew = rParent.top  + ((hParent - hChild) /2);
+   if (yNew < rWorkArea.top) {
+      yNew = rWorkArea.top;
+   } else if ((yNew+hChild) > rWorkArea.bottom) {
+      yNew = rWorkArea.bottom - hChild;
+   }
+
+   /* Set it, and return */
+   return SetWindowPos (hwndChild, NULL, xNew, yNew, 0, 0, SWP_NOSIZE |
+          SWP_NOZORDER);
+}
+
+/*----------------
+ *  BuildPngList
+ *----------------
+ */
+BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
+     int *pFileIndex)
+{
+    static TCHAR              szImgPathName [MAX_PATH];
+    static TCHAR              szImgFileName [MAX_PATH];
+    static TCHAR              szImgFindName [MAX_PATH];
+
+    WIN32_FIND_DATA           finddata;
+    HANDLE                    hFind;
+
+    static TCHAR              szTmp [MAX_PATH];
+    BOOL                      bOk;
+    int                       i, ii;
+    int                       j, jj;
+
+    /* free previous file-list */
+
+    if (*ppFileList != NULL)
+    {
+        free (*ppFileList);
+        *ppFileList = NULL;
+    }
+
+    /* extract foldername, filename and search-name */
+
+    strcpy (szImgPathName, pstrPathName);
+    strcpy (szImgFileName, strrchr (pstrPathName, '\\') + 1);
+
+    strcpy (szImgFindName, szImgPathName);
+    *(strrchr (szImgFindName, '\\') + 1) = '\0';
+    strcat (szImgFindName, "*.png");
+
+    /* first cycle: count number of files in directory for memory allocation */
+
+    *pFileCount = 0;
+
+    hFind = FindFirstFile(szImgFindName, &finddata);
+    bOk = (hFind != (HANDLE) -1);
+
+    while (bOk)
+    {
+        *pFileCount += 1;
+        bOk = FindNextFile(hFind, &finddata);
+    }
+    FindClose(hFind);
+
+    /* allocation memory for file-list */
+
+    *ppFileList = (TCHAR *) malloc (*pFileCount * MAX_PATH);
+
+    /* second cycle: read directory and store filenames in file-list */
+
+    hFind = FindFirstFile(szImgFindName, &finddata);
+    bOk = (hFind != (HANDLE) -1);
+
+    i = 0;
+    ii = 0;
+    while (bOk)
+    {
+        strcpy (*ppFileList + ii, szImgPathName);
+        strcpy (strrchr(*ppFileList + ii, '\\') + 1, finddata.cFileName);
+
+        if (strcmp(pstrPathName, *ppFileList + ii) == 0)
+            *pFileIndex = i;
+
+        ii += MAX_PATH;
+        i++;
+
+        bOk = FindNextFile(hFind, &finddata);
+    }
+    FindClose(hFind);
+
+    /* finally we must sort the file-list */
+
+    for (i = 0; i < *pFileCount - 1; i++)
+    {
+        ii = i * MAX_PATH;
+        for (j = i+1; j < *pFileCount; j++)
+        {
+            jj = j * MAX_PATH;
+            if (strcmp (*ppFileList + ii, *ppFileList + jj) > 0)
+            {
+                strcpy (szTmp, *ppFileList + jj);
+                strcpy (*ppFileList + jj, *ppFileList + ii);
+                strcpy (*ppFileList + ii, szTmp);
+
+                /* check if this was the current image that we moved */
+
+                if (*pFileIndex == i)
+                    *pFileIndex = j;
+                else
+                    if (*pFileIndex == j)
+                        *pFileIndex = i;
+            }
+        }
+    }
+
+    return TRUE;
+}
+
+/*----------------
+ *  SearchPngList
+ *----------------
+ */
+
+BOOL SearchPngList (
+        TCHAR *pFileList, int FileCount, int *pFileIndex,
+        PTSTR pstrPrevName, PTSTR pstrNextName)
+{
+    if (FileCount > 0)
+    {
+        /* get previous entry */
+
+        if (pstrPrevName != NULL)
+        {
+            if (*pFileIndex > 0)
+                *pFileIndex -= 1;
+            else
+                *pFileIndex = FileCount - 1;
+
+            strcpy (pstrPrevName, pFileList + (*pFileIndex * MAX_PATH));
+        }
+
+        /* get next entry */
+
+        if (pstrNextName != NULL)
+        {
+            if (*pFileIndex < FileCount - 1)
+                *pFileIndex += 1;
+            else
+                *pFileIndex = 0;
+
+            strcpy (pstrNextName, pFileList + (*pFileIndex * MAX_PATH));
+        }
+
+        return TRUE;
+    }
+    else
+    {
+        return FALSE;
+    }
+}
+
+/*-----------------
+ *  LoadImageFile
+ *-----------------
+ */
+
+BOOL LoadImageFile (HWND hwnd, PTSTR pstrPathName,
+                png_byte **ppbImage, int *pxImgSize, int *pyImgSize,
+                int *piChannels, png_color *pBkgColor)
+{
+    static TCHAR szTmp [MAX_PATH];
+
+    /* if there's an existing PNG, free the memory */
+
+    if (*ppbImage)
+    {
+        free (*ppbImage);
+        *ppbImage = NULL;
+    }
+
+    /* Load the entire PNG into memory */
+
+    SetCursor (LoadCursor (NULL, IDC_WAIT));
+    ShowCursor (TRUE);
+
+    PngLoadImage (pstrPathName, ppbImage, pxImgSize, pyImgSize, piChannels,
+                  pBkgColor);
+
+    ShowCursor (FALSE);
+    SetCursor (LoadCursor (NULL, IDC_ARROW));
+
+    if (*ppbImage != NULL)
+    {
+        sprintf (szTmp, "VisualPng - %s", strrchr(pstrPathName, '\\') + 1);
+        SetWindowText (hwnd, szTmp);
+    }
+    else
+    {
+        MessageBox (hwnd, TEXT ("Error in loading the PNG image"),
+            szProgName, MB_ICONEXCLAMATION | MB_OK);
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+/*----------------
+ *  DisplayImage
+ *----------------
+ */
+BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
+        BYTE **ppDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched)
+{
+    BYTE                       *pDib = *ppDib;
+    BYTE                       *pDiData = *ppDiData;
+    /* BITMAPFILEHEADER        *pbmfh; */
+    BITMAPINFOHEADER           *pbmih;
+    WORD                        wDIRowBytes;
+    png_color                   bkgBlack = {0, 0, 0};
+    png_color                   bkgGray  = {127, 127, 127};
+    png_color                   bkgWhite = {255, 255, 255};
+
+    /* allocate memory for the Device Independent bitmap */
+
+    wDIRowBytes = (WORD) ((3 * cxWinSize + 3L) >> 2) << 2;
+
+    if (pDib)
+    {
+        free (pDib);
+        pDib = NULL;
+    }
+
+    if (cyWinSize > ((size_t)(-1))/wDIRowBytes) {
+    {
+        MessageBox (hwnd, TEXT ("Visual PNG: image is too big");
+    }
+    if (!(pDib = (BYTE *) malloc (sizeof(BITMAPINFOHEADER) +
+        wDIRowBytes * cyWinSize)))
+    {
+        MessageBox (hwnd, TEXT ("Error in displaying the PNG image"),
+            szProgName, MB_ICONEXCLAMATION | MB_OK);
+        *ppDib = pDib = NULL;
+        return FALSE;
+    }
+    *ppDib = pDib;
+    memset (pDib, 0, sizeof(BITMAPINFOHEADER));
+
+    /* initialize the dib-structure */
+
+    pbmih = (BITMAPINFOHEADER *) pDib;
+    pbmih->biSize = sizeof(BITMAPINFOHEADER);
+    pbmih->biWidth = cxWinSize;
+    pbmih->biHeight = -((long) cyWinSize);
+    pbmih->biPlanes = 1;
+    pbmih->biBitCount = 24;
+    pbmih->biCompression = 0;
+    pDiData = pDib + sizeof(BITMAPINFOHEADER);
+    *ppDiData = pDiData;
+
+    /* first fill bitmap with gray and image border */
+
+    InitBitmap (pDiData, cxWinSize, cyWinSize);
+
+    /* then fill bitmap with image */
+
+    if (pbImage)
+    {
+        FillBitmap (
+            pDiData, cxWinSize, cyWinSize,
+            pbImage, cxImgSize, cyImgSize, cImgChannels,
+            bStretched);
+    }
+
+    return TRUE;
+}
+
+/*--------------
+ *  InitBitmap
+ *--------------
+ */
+BOOL InitBitmap (BYTE *pDiData, int cxWinSize, int cyWinSize)
+{
+    BYTE *dst;
+    int x, y, col;
+
+    /* initialize the background with gray */
+
+    dst = pDiData;
+    for (y = 0; y < cyWinSize; y++)
+    {
+        col = 0;
+        for (x = 0; x < cxWinSize; x++)
+        {
+            /* fill with GRAY */
+            *dst++ = 127;
+            *dst++ = 127;
+            *dst++ = 127;
+            col += 3;
+        }
+        /* rows start on 4 byte boundaries */
+        while ((col % 4) != 0)
+        {
+            dst++;
+            col++;
+        }
+    }
+
+    return TRUE;
+}
+
+/*--------------
+ *  FillBitmap
+ *--------------
+ */
+BOOL FillBitmap (
+        BYTE *pDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched)
+{
+    BYTE *pStretchedImage;
+    BYTE *pImg;
+    BYTE *src, *dst;
+    BYTE r, g, b, a;
+    const int cDIChannels = 3;
+    WORD wImgRowBytes;
+    WORD wDIRowBytes;
+    int cxNewSize, cyNewSize;
+    int cxImgPos, cyImgPos;
+    int xImg, yImg;
+    int xWin, yWin;
+    int xOld, yOld;
+    int xNew, yNew;
+
+    if (bStretched)
+    {
+        cxNewSize = cxWinSize - 2 * MARGIN;
+        cyNewSize = cyWinSize - 2 * MARGIN;
+
+        /* stretch the image to it's window determined size */
+
+        /* the following two are mathematically the same, but the first
+         * has side-effects because of rounding
+         */
+/*      if ((cyNewSize / cxNewSize) > (cyImgSize / cxImgSize)) */
+        if ((cyNewSize * cxImgSize) > (cyImgSize * cxNewSize))
+        {
+            cyNewSize = cxNewSize * cyImgSize / cxImgSize;
+            cxImgPos = MARGIN;
+            cyImgPos = (cyWinSize - cyNewSize) / 2;
+        }
+        else
+        {
+            cxNewSize = cyNewSize * cxImgSize / cyImgSize;
+            cyImgPos = MARGIN;
+            cxImgPos = (cxWinSize - cxNewSize) / 2;
+        }
+
+        if (cyNewSize > ((size_t)(-1))/(cImgChannels * cxNewSize)) {
+        {
+            MessageBox (hwnd, TEXT ("Visual PNG: stretched image is too big");
+        }
+        pStretchedImage = malloc (cImgChannels * cxNewSize * cyNewSize);
+        pImg = pStretchedImage;
+
+        for (yNew = 0; yNew < cyNewSize; yNew++)
+        {
+            yOld = yNew * cyImgSize / cyNewSize;
+            for (xNew = 0; xNew < cxNewSize; xNew++)
+            {
+                xOld = xNew * cxImgSize / cxNewSize;
+
+                r = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 0);
+                g = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 1);
+                b = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 2);
+                *pImg++ = r;
+                *pImg++ = g;
+                *pImg++ = b;
+                if (cImgChannels == 4)
+                {
+                    a = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld)
+                        + 3);
+                    *pImg++ = a;
+                }
+            }
+        }
+
+        /* calculate row-bytes */
+
+        wImgRowBytes = cImgChannels * cxNewSize;
+        wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
+
+        /* copy image to screen */
+
+        for (yImg = 0, yWin = cyImgPos; yImg < cyNewSize; yImg++, yWin++)
+        {
+            if (yWin >= cyWinSize - cyImgPos)
+                break;
+            src = pStretchedImage + yImg * wImgRowBytes;
+            dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
+
+            for (xImg = 0, xWin = cxImgPos; xImg < cxNewSize; xImg++, xWin++)
+            {
+                if (xWin >= cxWinSize - cxImgPos)
+                    break;
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dst++ = b; /* note the reverse order  */
+                *dst++ = g;
+                *dst++ = r;
+                if (cImgChannels == 4)
+                {
+                    a = *src++;
+                }
+            }
+        }
+
+        /* free memory */
+
+        if (pStretchedImage != NULL)
+        {
+            free (pStretchedImage);
+            pStretchedImage = NULL;
+        }
+
+    }
+
+    /* process the image not-stretched */
+
+    else
+    {
+        /* calculate the central position */
+
+        cxImgPos = (cxWinSize - cxImgSize) / 2;
+        cyImgPos = (cyWinSize - cyImgSize) / 2;
+
+        /* check for image larger than window */
+
+        if (cxImgPos < MARGIN)
+            cxImgPos = MARGIN;
+        if (cyImgPos < MARGIN)
+            cyImgPos = MARGIN;
+
+        /* calculate both row-bytes */
+
+        wImgRowBytes = cImgChannels * cxImgSize;
+        wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
+
+        /* copy image to screen */
+
+        for (yImg = 0, yWin = cyImgPos; yImg < cyImgSize; yImg++, yWin++)
+        {
+            if (yWin >= cyWinSize - MARGIN)
+                break;
+            src = pbImage + yImg * wImgRowBytes;
+            dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
+
+            for (xImg = 0, xWin = cxImgPos; xImg < cxImgSize; xImg++, xWin++)
+            {
+                if (xWin >= cxWinSize - MARGIN)
+                    break;
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dst++ = b; /* note the reverse order  */
+                *dst++ = g;
+                *dst++ = r;
+                if (cImgChannels == 4)
+                {
+                    a = *src++;
+                }
+            }
+        }
+    }
+
+    return TRUE;
+}
+
+/*-----------------
+ *  end of source
+ *-----------------
+ */
Index: /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.dsp
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.dsp	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.dsp	(revision 107811)
@@ -0,0 +1,147 @@
+# Microsoft Developer Studio Project File - Name="VisualPng" - Package Owner=<4>
+# Microsoft Developer Studio Generated Build File, Format Version 6.00
+# ** DO NOT EDIT **
+
+# TARGTYPE "Win32 (x86) Application" 0x0101
+
+CFG=VisualPng - Win32 Debug
+!MESSAGE This is not a valid makefile. To build this project using NMAKE,
+!MESSAGE use the Export Makefile command and run
+!MESSAGE 
+!MESSAGE NMAKE /f "VisualPng.mak".
+!MESSAGE 
+!MESSAGE You can specify a configuration when running NMAKE
+!MESSAGE by defining the macro CFG on the command line. For example:
+!MESSAGE 
+!MESSAGE NMAKE /f "VisualPng.mak" CFG="VisualPng - Win32 Debug"
+!MESSAGE 
+!MESSAGE Possible choices for configuration are:
+!MESSAGE 
+!MESSAGE "VisualPng - Win32 Release" (based on "Win32 (x86) Application")
+!MESSAGE "VisualPng - Win32 Debug" (based on "Win32 (x86) Application")
+!MESSAGE 
+
+# Begin Project
+# PROP AllowPerConfigDependencies 0
+# PROP Scc_ProjName ""
+# PROP Scc_LocalPath ""
+CPP=cl.exe
+MTL=midl.exe
+RSC=rc.exe
+
+!IF  "$(CFG)" == "VisualPng - Win32 Release"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 0
+# PROP BASE Output_Dir "Release"
+# PROP BASE Intermediate_Dir "Release"
+# PROP BASE Ignore_Export_Lib 0
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 0
+# PROP Output_Dir "Release"
+# PROP Intermediate_Dir "Release"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /W3 /O2 /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "NDEBUG" /D "PNG_NO_STDIO" /FD /c
+# SUBTRACT BASE CPP /YX
+# ADD CPP /nologo /MD /W3 /O2 /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "NDEBUG" /D "PNG_NO_STDIO" /FD /c
+# SUBTRACT CPP /YX
+# ADD BASE MTL /nologo /D "NDEBUG" /mktyplib203 /win32
+# ADD MTL /nologo /D "NDEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x409 /d "NDEBUG"
+# ADD RSC /l 0x409 /d "NDEBUG"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /machine:I386
+# ADD LINK32 ..\..\projects\visualc6\Win32_LIB_Release\libpng.lib ..\..\..\zlib\projects\visualc6\Win32_LIB_Release\zlib.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /machine:I386
+# Begin Special Build Tool
+OutDir=.\Release
+SOURCE="$(InputPath)"
+PostBuild_Cmds=$(outdir)\VisualPng.exe ..\..\contrib\pngsuite\basn6a16.png
+# End Special Build Tool
+
+!ELSEIF  "$(CFG)" == "VisualPng - Win32 Debug"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 1
+# PROP BASE Output_Dir "Debug"
+# PROP BASE Intermediate_Dir "Debug"
+# PROP BASE Ignore_Export_Lib 0
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 1
+# PROP Output_Dir "Debug"
+# PROP Intermediate_Dir "Debug"
+# PROP Ignore_Export_Lib 0
+# PROP Target_Dir ""
+# ADD BASE CPP /nologo /W3 /Gm /ZI /Od /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "_DEBUG" /D "PNG_NO_STDIO" /FD /GZ /c
+# SUBTRACT BASE CPP /YX
+# ADD CPP /nologo /MDd /W3 /Gm /ZI /Od /I "..\.." /I "..\..\..\zlib" /D "WIN32" /D "_DEBUG" /D "PNG_NO_STDIO" /FD /GZ /c
+# SUBTRACT CPP /YX
+# ADD BASE MTL /nologo /D "_DEBUG" /mktyplib203 /win32
+# ADD MTL /nologo /D "_DEBUG" /mktyplib203 /win32
+# ADD BASE RSC /l 0x409 /d "_DEBUG"
+# ADD RSC /l 0x409 /d "_DEBUG"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LINK32=link.exe
+# ADD BASE LINK32 kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /debug /machine:I386 /pdbtype:sept
+# ADD LINK32 ..\..\projects\visualc6\Win32_LIB_Release\libpng.lib ..\..\..\zlib\projects\visualc6\Win32_LIB_Release\zlib.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /subsystem:windows /debug /machine:I386 /nodefaultlib:"msvcrt.lib" /pdbtype:sept
+# Begin Special Build Tool
+OutDir=.\Debug
+SOURCE="$(InputPath)"
+PostBuild_Cmds=$(outdir)\VisualPng.exe ..\..\contrib\pngsuite\basn6a16.png
+# End Special Build Tool
+
+!ENDIF 
+
+# Begin Target
+
+# Name "VisualPng - Win32 Release"
+# Name "VisualPng - Win32 Debug"
+# Begin Group "Source Files"
+
+# PROP Default_Filter "cpp;c;cxx;rc;def;r;odl;idl;hpj;bat"
+# Begin Source File
+
+SOURCE=.\PngFile.c
+# End Source File
+# Begin Source File
+
+SOURCE=.\VisualPng.c
+# End Source File
+# End Group
+# Begin Group "Header Files"
+
+# PROP Default_Filter "h;hpp;hxx;hm;inl"
+# Begin Source File
+
+SOURCE=.\cexcept.h
+# End Source File
+# Begin Source File
+
+SOURCE=.\PngFile.h
+# End Source File
+# Begin Source File
+
+SOURCE=.\resource.h
+# End Source File
+# End Group
+# Begin Group "Resource Files"
+
+# PROP Default_Filter "ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe"
+# Begin Source File
+
+SOURCE=.\VisualPng.ico
+# End Source File
+# Begin Source File
+
+SOURCE=.\VisualPng.rc
+# End Source File
+# End Group
+# End Target
+# End Project
Index: /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.dsw
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.dsw	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.dsw	(revision 107811)
@@ -0,0 +1,29 @@
+Microsoft Developer Studio Workspace File, Format Version 6.00
+# WARNING: DO NOT EDIT OR DELETE THIS WORKSPACE FILE!
+
+###############################################################################
+
+Project: "VisualPng"=.\VisualPng.dsp - Package Owner=<4>
+
+Package=<5>
+{{{
+}}}
+
+Package=<4>
+{{{
+}}}
+
+###############################################################################
+
+Global:
+
+Package=<5>
+{{{
+}}}
+
+Package=<3>
+{{{
+}}}
+
+###############################################################################
+
Index: /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.rc
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.rc	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/visupng/VisualPng.rc	(revision 107811)
@@ -0,0 +1,152 @@
+//Microsoft Developer Studio generated resource script.
+//
+#include "resource.h"
+
+#define APSTUDIO_READONLY_SYMBOLS
+/////////////////////////////////////////////////////////////////////////////
+//
+// Generated from the TEXTINCLUDE 2 resource.
+//
+#include "afxres.h"
+
+/////////////////////////////////////////////////////////////////////////////
+#undef APSTUDIO_READONLY_SYMBOLS
+
+/////////////////////////////////////////////////////////////////////////////
+// English (U.S.) resources
+
+#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)
+#ifdef _WIN32
+LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
+#pragma code_page(1252)
+#endif //_WIN32
+
+#ifdef APSTUDIO_INVOKED
+/////////////////////////////////////////////////////////////////////////////
+//
+// TEXTINCLUDE
+//
+
+1 TEXTINCLUDE DISCARDABLE 
+BEGIN
+    "resource.h\0"
+END
+
+2 TEXTINCLUDE DISCARDABLE 
+BEGIN
+    "#include ""afxres.h""\r\n"
+    "\0"
+END
+
+3 TEXTINCLUDE DISCARDABLE 
+BEGIN
+    "\r\n"
+    "\0"
+END
+
+#endif    // APSTUDIO_INVOKED
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Menu
+//
+
+VISUALPNG MENU DISCARDABLE 
+BEGIN
+    POPUP "&File"
+    BEGIN
+        MENUITEM "&Open Image...\tCtrl+O",      IDM_FILE_OPEN
+        MENUITEM "Save &As...",                 IDM_FILE_SAVE
+        MENUITEM SEPARATOR
+        MENUITEM "&Next Image\tCtrl+N",         IDM_FILE_NEXT
+        MENUITEM "Pre&vious Image\tCtrl+V",     IDM_FILE_PREVIOUS
+        MENUITEM SEPARATOR
+        MENUITEM "E&xit\tAlt+X",                IDM_FILE_EXIT
+    END
+    POPUP "&Options"
+    BEGIN
+        MENUITEM "&Stretch",                    IDM_OPTIONS_STRETCH, CHECKED
+    END
+    POPUP "&Help"
+    BEGIN
+        MENUITEM "&About",                      IDM_HELP_ABOUT
+    END
+END
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Accelerator
+//
+
+VISUALPNG ACCELERATORS DISCARDABLE 
+BEGIN
+    "N",            IDM_FILE_NEXT,          VIRTKEY, CONTROL, NOINVERT
+    "O",            IDM_FILE_OPEN,          VIRTKEY, CONTROL, NOINVERT
+    "P",            IDM_FILE_PREVIOUS,      VIRTKEY, CONTROL, NOINVERT
+    "V",            IDM_FILE_PREVIOUS,      VIRTKEY, CONTROL, NOINVERT
+    "X",            IDM_FILE_EXIT,          VIRTKEY, ALT, NOINVERT
+END
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Icon
+//
+
+// Icon with lowest ID value placed first to ensure application icon
+// remains consistent on all systems.
+VISUALPNG               ICON    DISCARDABLE     "VisualPng.ico"
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Dialog
+//
+
+ABOUTBOX DIALOG DISCARDABLE  0, 0, 186, 94
+STYLE DS_MODALFRAME | WS_POPUP
+FONT 8, "MS Sans Serif"
+BEGIN
+    DEFPUSHBUTTON   "OK",IDOK,68,67,50,14
+    CTEXT           "VisualPng 1.0  -  June 2000",IDC_STATIC,49,14,88,8
+    LTEXT           "a PNG image viewer",IDC_STATIC,60,30,66,8
+    LTEXT           "(c) Willem van Schaik, 2000",IDC_STATIC,48,52,90,8
+    LTEXT           "to demonstrate the use of libpng in Visual C",
+                    IDC_STATIC,25,38,136,8
+END
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// DESIGNINFO
+//
+
+#ifdef APSTUDIO_INVOKED
+GUIDELINES DESIGNINFO DISCARDABLE 
+BEGIN
+    "ABOUTBOX", DIALOG
+    BEGIN
+        LEFTMARGIN, 7
+        RIGHTMARGIN, 179
+        TOPMARGIN, 7
+        BOTTOMMARGIN, 87
+    END
+END
+#endif    // APSTUDIO_INVOKED
+
+#endif    // English (U.S.) resources
+/////////////////////////////////////////////////////////////////////////////
+
+
+
+#ifndef APSTUDIO_INVOKED
+/////////////////////////////////////////////////////////////////////////////
+//
+// Generated from the TEXTINCLUDE 3 resource.
+//
+
+
+/////////////////////////////////////////////////////////////////////////////
+#endif    // not APSTUDIO_INVOKED
+
Index: /trunk/src/libs/libpng-1.6.45/contrib/visupng/cexcept.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/visupng/cexcept.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/visupng/cexcept.h	(revision 107811)
@@ -0,0 +1,248 @@
+/*===
+cexcept.h 2.0.1 (2008-Jul-19-Sat)
+http://www.nicemice.net/cexcept/
+Adam M. Costello
+http://www.nicemice.net/amc/
+
+An interface for exception-handling in ANSI C (C89 and subsequent ISO
+standards), developed jointly with Cosmin Truta.
+
+    Copyright (c) 2000-2008 Adam M. Costello and Cosmin Truta.
+    This software may be modified only if its author and version
+    information is updated accurately, and may be redistributed
+    only if accompanied by this unaltered notice.  Subject to those
+    restrictions, permission is granted to anyone to do anything
+    with this software.  The copyright holders make no guarantees
+    regarding this software, and are not responsible for any damage
+    resulting from its use.
+
+The cexcept interface is not compatible with and cannot interact
+with system exceptions (like division by zero or memory segmentation
+violation), compiler-generated exceptions (like C++ exceptions), or
+other exception-handling interfaces.
+
+When using this interface across multiple .c files, do not include
+this header file directly.  Instead, create a wrapper header file that
+includes this header file and then invokes the define_exception_type
+macro (see below).  The .c files should then include that header file.
+
+The interface consists of one type, one well-known name, and six macros.
+
+
+define_exception_type(type_name);
+
+    This macro is used like an external declaration.  It specifies
+    the type of object that gets copied from the exception thrower to
+    the exception catcher.  The type_name can be any type that can be
+    assigned to, that is, a non-constant arithmetic type, struct, union,
+    or pointer.  Examples:
+
+        define_exception_type(int);
+
+        enum exception { out_of_memory, bad_arguments, disk_full };
+        define_exception_type(enum exception);
+
+        struct exception { int code; const char *msg; };
+        define_exception_type(struct exception);
+
+    Because throwing an exception causes the object to be copied (not
+    just once, but twice), programmers may wish to consider size when
+    choosing the exception type.
+
+
+struct exception_context;
+
+    This type may be used after the define_exception_type() macro has
+    been invoked.  A struct exception_context must be known to both
+    the thrower and the catcher.  It is expected that there be one
+    context for each thread that uses exceptions.  It would certainly
+    be dangerous for multiple threads to access the same context.
+    One thread can use multiple contexts, but that is likely to be
+    confusing and not typically useful.  The application can allocate
+    this structure in any way it pleases--automatic, static, or dynamic.
+    The application programmer should pretend not to know the structure
+    members, which are subject to change.
+
+
+struct exception_context *the_exception_context;
+
+    The Try/Catch and Throw statements (described below) implicitly
+    refer to a context, using the name the_exception_context.  It is
+    the application's responsibility to make sure that this name yields
+    the address of a mutable (non-constant) struct exception_context
+    wherever those statements are used.  Subject to that constraint, the
+    application may declare a variable of this name anywhere it likes
+    (inside a function, in a parameter list, or externally), and may
+    use whatever storage class specifiers (static, extern, etc) or type
+    qualifiers (const, volatile, etc) it likes.  Examples:
+
+        static struct exception_context
+          * const the_exception_context = &foo;
+
+        { struct exception_context *the_exception_context = bar; ... }
+
+        int blah(struct exception_context *the_exception_context, ...);
+
+        extern struct exception_context the_exception_context[1];
+
+    The last example illustrates a trick that avoids creating a pointer
+    object separate from the structure object.
+
+    The name could even be a macro, for example:
+
+        struct exception_context ec_array[numthreads];
+        #define the_exception_context (ec_array + thread_id)
+
+    Be aware that the_exception_context is used several times by the
+    Try/Catch/Throw macros, so it shouldn't be expensive or have side
+    effects.  The expansion must be a drop-in replacement for an
+    identifier, so it's safest to put parentheses around it.
+
+
+void init_exception_context(struct exception_context *ec);
+
+    For context structures allocated statically (by an external
+    definition or using the "static" keyword), the implicit
+    initialization to all zeros is sufficient, but contexts allocated
+    by other means must be initialized using this macro before they
+    are used by a Try/Catch statement.  It does no harm to initialize
+    a context more than once (by using this macro on a statically
+    allocated context, or using this macro twice on the same context),
+    but a context must not be re-initialized after it has been used by a
+    Try/Catch statement.
+
+
+Try statement
+Catch (expression) statement
+
+    The Try/Catch/Throw macros are capitalized in order to avoid
+    confusion with the C++ keywords, which have subtly different
+    semantics.
+
+    A Try/Catch statement has a syntax similar to an if/else statement,
+    except that the parenthesized expression goes after the second
+    keyword rather than the first.  As with if/else, there are two
+    clauses, each of which may be a simple statement ending with a
+    semicolon or a brace-enclosed compound statement.  But whereas
+    the else clause is optional, the Catch clause is required.  The
+    expression must be a modifiable lvalue (something capable of being
+    assigned to) of the same type (disregarding type qualifiers) that
+    was passed to define_exception_type().
+
+    If a Throw that uses the same exception context as the Try/Catch is
+    executed within the Try clause (typically within a function called
+    by the Try clause), and the exception is not caught by a nested
+    Try/Catch statement, then a copy of the exception will be assigned
+    to the expression, and control will jump to the Catch clause.  If no
+    such Throw is executed, then the assignment is not performed, and
+    the Catch clause is not executed.
+
+    The expression is not evaluated unless and until the exception is
+    caught, which is significant if it has side effects, for example:
+
+        Try foo();
+        Catch (p[++i].e) { ... }
+
+    IMPORTANT: Jumping into or out of a Try clause (for example via
+    return, break, continue, goto, longjmp) is forbidden--the compiler
+    will not complain, but bad things will happen at run-time.  Jumping
+    into or out of a Catch clause is okay, and so is jumping around
+    inside a Try clause.  In many cases where one is tempted to return
+    from a Try clause, it will suffice to use Throw, and then return
+    from the Catch clause.  Another option is to set a flag variable and
+    use goto to jump to the end of the Try clause, then check the flag
+    after the Try/Catch statement.
+
+    IMPORTANT: The values of any non-volatile automatic variables
+    changed within the Try clause are undefined after an exception is
+    caught.  Therefore, variables modified inside the Try block whose
+    values are needed later outside the Try block must either use static
+    storage or be declared with the "volatile" type qualifier.
+
+
+Throw expression;
+
+    A Throw statement is very much like a return statement, except that
+    the expression is required.  Whereas return jumps back to the place
+    where the current function was called, Throw jumps back to the Catch
+    clause of the innermost enclosing Try clause.  The expression must
+    be compatible with the type passed to define_exception_type().  The
+    exception must be caught, otherwise the program may crash.
+
+    Slight limitation:  If the expression is a comma-expression, it must
+    be enclosed in parentheses.
+
+
+Try statement
+Catch_anonymous statement
+
+    When the value of the exception is not needed, a Try/Catch statement
+    can use Catch_anonymous instead of Catch (expression).
+
+
+Everything below this point is for the benefit of the compiler.  The
+application programmer should pretend not to know any of it, because it
+is subject to change.
+
+===*/
+
+
+#ifndef CEXCEPT_H
+#define CEXCEPT_H
+
+
+#include <setjmp.h>
+
+#define define_exception_type(etype) \
+struct exception_context { \
+  jmp_buf *penv; \
+  int caught; \
+  volatile struct { etype etmp; } v; \
+}
+
+/* etmp must be volatile because the application might use automatic */
+/* storage for the_exception_context, and etmp is modified between   */
+/* the calls to setjmp() and longjmp().  A wrapper struct is used to */
+/* avoid warnings about a duplicate volatile qualifier in case etype */
+/* already includes it.                                              */
+
+#define init_exception_context(ec) ((void)((ec)->penv = 0))
+
+#define Try \
+  { \
+    jmp_buf *exception__prev, exception__env; \
+    exception__prev = the_exception_context->penv; \
+    the_exception_context->penv = &exception__env; \
+    if (setjmp(exception__env) == 0) { \
+      do
+
+#define exception__catch(action) \
+      while (the_exception_context->caught = 0, \
+             the_exception_context->caught); \
+    } \
+    else { \
+      the_exception_context->caught = 1; \
+    } \
+    the_exception_context->penv = exception__prev; \
+  } \
+  if (!the_exception_context->caught || action) { } \
+  else
+
+#define Catch(e) exception__catch(((e) = the_exception_context->v.etmp, 0))
+#define Catch_anonymous exception__catch(0)
+
+/* Try ends with do, and Catch begins with while(0) and ends with     */
+/* else, to ensure that Try/Catch syntax is similar to if/else        */
+/* syntax.                                                            */
+/*                                                                    */
+/* The 0 in while(0) is expressed as x=0,x in order to appease        */
+/* compilers that warn about constant expressions inside while().     */
+/* Most compilers should still recognize that the condition is always */
+/* false and avoid generating code for it.                            */
+
+#define Throw \
+  for (;; longjmp(*the_exception_context->penv, 1)) \
+    the_exception_context->v.etmp =
+
+
+#endif /* CEXCEPT_H */
Index: /trunk/src/libs/libpng-1.6.45/contrib/visupng/resource.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/contrib/visupng/resource.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/contrib/visupng/resource.h	(revision 107811)
@@ -0,0 +1,23 @@
+//{{NO_DEPENDENCIES}}
+// Microsoft Developer Studio generated include file.
+// Used by VisualPng.rc
+//
+#define IDM_FILE_OPEN                   40001
+#define IDM_FILE_SAVE                   40002
+#define IDM_FILE_NEXT                   40003
+#define IDM_FILE_PREVIOUS               40004
+#define IDM_FILE_EXIT                   40005
+#define IDM_OPTIONS_BACKGROUND          40006
+#define IDM_OPTIONS_STRETCH             40007
+#define IDM_HELP_ABOUT                  40008
+
+// Next default values for new objects
+//
+#ifdef APSTUDIO_INVOKED
+#ifndef APSTUDIO_READONLY_SYMBOLS
+#define _APS_NEXT_RESOURCE_VALUE        113
+#define _APS_NEXT_COMMAND_VALUE         40009
+#define _APS_NEXT_CONTROL_VALUE         1001
+#define _APS_NEXT_SYMED_VALUE           101
+#endif
+#endif
Index: /trunk/src/libs/libpng-1.6.45/depcomp
===================================================================
--- /trunk/src/libs/libpng-1.6.45/depcomp	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/depcomp	(revision 107811)
@@ -0,0 +1,791 @@
+#! /bin/sh
+# depcomp - compile a program generating dependencies as side-effects
+
+scriptversion=2018-03-07.03; # UTC
+
+# Copyright (C) 1999-2021 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# Originally written by Alexandre Oliva <oliva@dcc.unicamp.br>.
+
+case $1 in
+  '')
+    echo "$0: No command.  Try '$0 --help' for more information." 1>&2
+    exit 1;
+    ;;
+  -h | --h*)
+    cat <<\EOF
+Usage: depcomp [--help] [--version] PROGRAM [ARGS]
+
+Run PROGRAMS ARGS to compile a file, generating dependencies
+as side-effects.
+
+Environment variables:
+  depmode     Dependency tracking mode.
+  source      Source file read by 'PROGRAMS ARGS'.
+  object      Object file output by 'PROGRAMS ARGS'.
+  DEPDIR      directory where to store dependencies.
+  depfile     Dependency file to output.
+  tmpdepfile  Temporary file to use when outputting dependencies.
+  libtool     Whether libtool is used (yes/no).
+
+Report bugs to <bug-automake@gnu.org>.
+EOF
+    exit $?
+    ;;
+  -v | --v*)
+    echo "depcomp $scriptversion"
+    exit $?
+    ;;
+esac
+
+# Get the directory component of the given path, and save it in the
+# global variables '$dir'.  Note that this directory component will
+# be either empty or ending with a '/' character.  This is deliberate.
+set_dir_from ()
+{
+  case $1 in
+    */*) dir=`echo "$1" | sed -e 's|/[^/]*$|/|'`;;
+      *) dir=;;
+  esac
+}
+
+# Get the suffix-stripped basename of the given path, and save it the
+# global variable '$base'.
+set_base_from ()
+{
+  base=`echo "$1" | sed -e 's|^.*/||' -e 's/\.[^.]*$//'`
+}
+
+# If no dependency file was actually created by the compiler invocation,
+# we still have to create a dummy depfile, to avoid errors with the
+# Makefile "include basename.Plo" scheme.
+make_dummy_depfile ()
+{
+  echo "#dummy" > "$depfile"
+}
+
+# Factor out some common post-processing of the generated depfile.
+# Requires the auxiliary global variable '$tmpdepfile' to be set.
+aix_post_process_depfile ()
+{
+  # If the compiler actually managed to produce a dependency file,
+  # post-process it.
+  if test -f "$tmpdepfile"; then
+    # Each line is of the form 'foo.o: dependency.h'.
+    # Do two passes, one to just change these to
+    #   $object: dependency.h
+    # and one to simply output
+    #   dependency.h:
+    # which is needed to avoid the deleted-header problem.
+    { sed -e "s,^.*\.[$lower]*:,$object:," < "$tmpdepfile"
+      sed -e "s,^.*\.[$lower]*:[$tab ]*,," -e 's,$,:,' < "$tmpdepfile"
+    } > "$depfile"
+    rm -f "$tmpdepfile"
+  else
+    make_dummy_depfile
+  fi
+}
+
+# A tabulation character.
+tab='	'
+# A newline character.
+nl='
+'
+# Character ranges might be problematic outside the C locale.
+# These definitions help.
+upper=ABCDEFGHIJKLMNOPQRSTUVWXYZ
+lower=abcdefghijklmnopqrstuvwxyz
+digits=0123456789
+alpha=${upper}${lower}
+
+if test -z "$depmode" || test -z "$source" || test -z "$object"; then
+  echo "depcomp: Variables source, object and depmode must be set" 1>&2
+  exit 1
+fi
+
+# Dependencies for sub/bar.o or sub/bar.obj go into sub/.deps/bar.Po.
+depfile=${depfile-`echo "$object" |
+  sed 's|[^\\/]*$|'${DEPDIR-.deps}'/&|;s|\.\([^.]*\)$|.P\1|;s|Pobj$|Po|'`}
+tmpdepfile=${tmpdepfile-`echo "$depfile" | sed 's/\.\([^.]*\)$/.T\1/'`}
+
+rm -f "$tmpdepfile"
+
+# Avoid interferences from the environment.
+gccflag= dashmflag=
+
+# Some modes work just like other modes, but use different flags.  We
+# parameterize here, but still list the modes in the big case below,
+# to make depend.m4 easier to write.  Note that we *cannot* use a case
+# here, because this file can only contain one case statement.
+if test "$depmode" = hp; then
+  # HP compiler uses -M and no extra arg.
+  gccflag=-M
+  depmode=gcc
+fi
+
+if test "$depmode" = dashXmstdout; then
+  # This is just like dashmstdout with a different argument.
+  dashmflag=-xM
+  depmode=dashmstdout
+fi
+
+cygpath_u="cygpath -u -f -"
+if test "$depmode" = msvcmsys; then
+  # This is just like msvisualcpp but w/o cygpath translation.
+  # Just convert the backslash-escaped backslashes to single forward
+  # slashes to satisfy depend.m4
+  cygpath_u='sed s,\\\\,/,g'
+  depmode=msvisualcpp
+fi
+
+if test "$depmode" = msvc7msys; then
+  # This is just like msvc7 but w/o cygpath translation.
+  # Just convert the backslash-escaped backslashes to single forward
+  # slashes to satisfy depend.m4
+  cygpath_u='sed s,\\\\,/,g'
+  depmode=msvc7
+fi
+
+if test "$depmode" = xlc; then
+  # IBM C/C++ Compilers xlc/xlC can output gcc-like dependency information.
+  gccflag=-qmakedep=gcc,-MF
+  depmode=gcc
+fi
+
+case "$depmode" in
+gcc3)
+## gcc 3 implements dependency tracking that does exactly what
+## we want.  Yay!  Note: for some reason libtool 1.4 doesn't like
+## it if -MD -MP comes after the -MF stuff.  Hmm.
+## Unfortunately, FreeBSD c89 acceptance of flags depends upon
+## the command line argument order; so add the flags where they
+## appear in depend2.am.  Note that the slowdown incurred here
+## affects only configure: in makefiles, %FASTDEP% shortcuts this.
+  for arg
+  do
+    case $arg in
+    -c) set fnord "$@" -MT "$object" -MD -MP -MF "$tmpdepfile" "$arg" ;;
+    *)  set fnord "$@" "$arg" ;;
+    esac
+    shift # fnord
+    shift # $arg
+  done
+  "$@"
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  mv "$tmpdepfile" "$depfile"
+  ;;
+
+gcc)
+## Note that this doesn't just cater to obsosete pre-3.x GCC compilers.
+## but also to in-use compilers like IMB xlc/xlC and the HP C compiler.
+## (see the conditional assignment to $gccflag above).
+## There are various ways to get dependency output from gcc.  Here's
+## why we pick this rather obscure method:
+## - Don't want to use -MD because we'd like the dependencies to end
+##   up in a subdir.  Having to rename by hand is ugly.
+##   (We might end up doing this anyway to support other compilers.)
+## - The DEPENDENCIES_OUTPUT environment variable makes gcc act like
+##   -MM, not -M (despite what the docs say).  Also, it might not be
+##   supported by the other compilers which use the 'gcc' depmode.
+## - Using -M directly means running the compiler twice (even worse
+##   than renaming).
+  if test -z "$gccflag"; then
+    gccflag=-MD,
+  fi
+  "$@" -Wp,"$gccflag$tmpdepfile"
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+  echo "$object : \\" > "$depfile"
+  # The second -e expression handles DOS-style file names with drive
+  # letters.
+  sed -e 's/^[^:]*: / /' \
+      -e 's/^['$alpha']:\/[^:]*: / /' < "$tmpdepfile" >> "$depfile"
+## This next piece of magic avoids the "deleted header file" problem.
+## The problem is that when a header file which appears in a .P file
+## is deleted, the dependency causes make to die (because there is
+## typically no way to rebuild the header).  We avoid this by adding
+## dummy dependencies for each header file.  Too bad gcc doesn't do
+## this for us directly.
+## Some versions of gcc put a space before the ':'.  On the theory
+## that the space means something, we add a space to the output as
+## well.  hp depmode also adds that space, but also prefixes the VPATH
+## to the object.  Take care to not repeat it in the output.
+## Some versions of the HPUX 10.20 sed can't process this invocation
+## correctly.  Breaking it into two sed invocations is a workaround.
+  tr ' ' "$nl" < "$tmpdepfile" \
+    | sed -e 's/^\\$//' -e '/^$/d' -e "s|.*$object$||" -e '/:$/d' \
+    | sed -e 's/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+hp)
+  # This case exists only to let depend.m4 do its work.  It works by
+  # looking at the text of this script.  This case will never be run,
+  # since it is checked for above.
+  exit 1
+  ;;
+
+sgi)
+  if test "$libtool" = yes; then
+    "$@" "-Wp,-MDupdate,$tmpdepfile"
+  else
+    "$@" -MDupdate "$tmpdepfile"
+  fi
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+
+  if test -f "$tmpdepfile"; then  # yes, the sourcefile depend on other files
+    echo "$object : \\" > "$depfile"
+    # Clip off the initial element (the dependent).  Don't try to be
+    # clever and replace this with sed code, as IRIX sed won't handle
+    # lines with more than a fixed number of characters (4096 in
+    # IRIX 6.2 sed, 8192 in IRIX 6.5).  We also remove comment lines;
+    # the IRIX cc adds comments like '#:fec' to the end of the
+    # dependency line.
+    tr ' ' "$nl" < "$tmpdepfile" \
+      | sed -e 's/^.*\.o://' -e 's/#.*$//' -e '/^$/ d' \
+      | tr "$nl" ' ' >> "$depfile"
+    echo >> "$depfile"
+    # The second pass generates a dummy entry for each header file.
+    tr ' ' "$nl" < "$tmpdepfile" \
+      | sed -e 's/^.*\.o://' -e 's/#.*$//' -e '/^$/ d' -e 's/$/:/' \
+      >> "$depfile"
+  else
+    make_dummy_depfile
+  fi
+  rm -f "$tmpdepfile"
+  ;;
+
+xlc)
+  # This case exists only to let depend.m4 do its work.  It works by
+  # looking at the text of this script.  This case will never be run,
+  # since it is checked for above.
+  exit 1
+  ;;
+
+aix)
+  # The C for AIX Compiler uses -M and outputs the dependencies
+  # in a .u file.  In older versions, this file always lives in the
+  # current directory.  Also, the AIX compiler puts '$object:' at the
+  # start of each line; $object doesn't have directory information.
+  # Version 6 uses the directory in both cases.
+  set_dir_from "$object"
+  set_base_from "$object"
+  if test "$libtool" = yes; then
+    tmpdepfile1=$dir$base.u
+    tmpdepfile2=$base.u
+    tmpdepfile3=$dir.libs/$base.u
+    "$@" -Wc,-M
+  else
+    tmpdepfile1=$dir$base.u
+    tmpdepfile2=$dir$base.u
+    tmpdepfile3=$dir$base.u
+    "$@" -M
+  fi
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
+    exit $stat
+  fi
+
+  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
+  do
+    test -f "$tmpdepfile" && break
+  done
+  aix_post_process_depfile
+  ;;
+
+tcc)
+  # tcc (Tiny C Compiler) understand '-MD -MF file' since version 0.9.26
+  # FIXME: That version still under development at the moment of writing.
+  #        Make that this statement remains true also for stable, released
+  #        versions.
+  # It will wrap lines (doesn't matter whether long or short) with a
+  # trailing '\', as in:
+  #
+  #   foo.o : \
+  #    foo.c \
+  #    foo.h \
+  #
+  # It will put a trailing '\' even on the last line, and will use leading
+  # spaces rather than leading tabs (at least since its commit 0394caf7
+  # "Emit spaces for -MD").
+  "$@" -MD -MF "$tmpdepfile"
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+  # Each non-empty line is of the form 'foo.o : \' or ' dep.h \'.
+  # We have to change lines of the first kind to '$object: \'.
+  sed -e "s|.*:|$object :|" < "$tmpdepfile" > "$depfile"
+  # And for each line of the second kind, we have to emit a 'dep.h:'
+  # dummy dependency, to avoid the deleted-header problem.
+  sed -n -e 's|^  *\(.*\) *\\$|\1:|p' < "$tmpdepfile" >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+## The order of this option in the case statement is important, since the
+## shell code in configure will try each of these formats in the order
+## listed in this file.  A plain '-MD' option would be understood by many
+## compilers, so we must ensure this comes after the gcc and icc options.
+pgcc)
+  # Portland's C compiler understands '-MD'.
+  # Will always output deps to 'file.d' where file is the root name of the
+  # source file under compilation, even if file resides in a subdirectory.
+  # The object file name does not affect the name of the '.d' file.
+  # pgcc 10.2 will output
+  #    foo.o: sub/foo.c sub/foo.h
+  # and will wrap long lines using '\' :
+  #    foo.o: sub/foo.c ... \
+  #     sub/foo.h ... \
+  #     ...
+  set_dir_from "$object"
+  # Use the source, not the object, to determine the base name, since
+  # that's sadly what pgcc will do too.
+  set_base_from "$source"
+  tmpdepfile=$base.d
+
+  # For projects that build the same source file twice into different object
+  # files, the pgcc approach of using the *source* file root name can cause
+  # problems in parallel builds.  Use a locking strategy to avoid stomping on
+  # the same $tmpdepfile.
+  lockdir=$base.d-lock
+  trap "
+    echo '$0: caught signal, cleaning up...' >&2
+    rmdir '$lockdir'
+    exit 1
+  " 1 2 13 15
+  numtries=100
+  i=$numtries
+  while test $i -gt 0; do
+    # mkdir is a portable test-and-set.
+    if mkdir "$lockdir" 2>/dev/null; then
+      # This process acquired the lock.
+      "$@" -MD
+      stat=$?
+      # Release the lock.
+      rmdir "$lockdir"
+      break
+    else
+      # If the lock is being held by a different process, wait
+      # until the winning process is done or we timeout.
+      while test -d "$lockdir" && test $i -gt 0; do
+        sleep 1
+        i=`expr $i - 1`
+      done
+    fi
+    i=`expr $i - 1`
+  done
+  trap - 1 2 13 15
+  if test $i -le 0; then
+    echo "$0: failed to acquire lock after $numtries attempts" >&2
+    echo "$0: check lockdir '$lockdir'" >&2
+    exit 1
+  fi
+
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+  # Each line is of the form `foo.o: dependent.h',
+  # or `foo.o: dep1.h dep2.h \', or ` dep3.h dep4.h \'.
+  # Do two passes, one to just change these to
+  # `$object: dependent.h' and one to simply `dependent.h:'.
+  sed "s,^[^:]*:,$object :," < "$tmpdepfile" > "$depfile"
+  # Some versions of the HPUX 10.20 sed can't process this invocation
+  # correctly.  Breaking it into two sed invocations is a workaround.
+  sed 's,^[^:]*: \(.*\)$,\1,;s/^\\$//;/^$/d;/:$/d' < "$tmpdepfile" \
+    | sed -e 's/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+hp2)
+  # The "hp" stanza above does not work with aCC (C++) and HP's ia64
+  # compilers, which have integrated preprocessors.  The correct option
+  # to use with these is +Maked; it writes dependencies to a file named
+  # 'foo.d', which lands next to the object file, wherever that
+  # happens to be.
+  # Much of this is similar to the tru64 case; see comments there.
+  set_dir_from  "$object"
+  set_base_from "$object"
+  if test "$libtool" = yes; then
+    tmpdepfile1=$dir$base.d
+    tmpdepfile2=$dir.libs/$base.d
+    "$@" -Wc,+Maked
+  else
+    tmpdepfile1=$dir$base.d
+    tmpdepfile2=$dir$base.d
+    "$@" +Maked
+  fi
+  stat=$?
+  if test $stat -ne 0; then
+     rm -f "$tmpdepfile1" "$tmpdepfile2"
+     exit $stat
+  fi
+
+  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2"
+  do
+    test -f "$tmpdepfile" && break
+  done
+  if test -f "$tmpdepfile"; then
+    sed -e "s,^.*\.[$lower]*:,$object:," "$tmpdepfile" > "$depfile"
+    # Add 'dependent.h:' lines.
+    sed -ne '2,${
+               s/^ *//
+               s/ \\*$//
+               s/$/:/
+               p
+             }' "$tmpdepfile" >> "$depfile"
+  else
+    make_dummy_depfile
+  fi
+  rm -f "$tmpdepfile" "$tmpdepfile2"
+  ;;
+
+tru64)
+  # The Tru64 compiler uses -MD to generate dependencies as a side
+  # effect.  'cc -MD -o foo.o ...' puts the dependencies into 'foo.o.d'.
+  # At least on Alpha/Redhat 6.1, Compaq CCC V6.2-504 seems to put
+  # dependencies in 'foo.d' instead, so we check for that too.
+  # Subdirectories are respected.
+  set_dir_from  "$object"
+  set_base_from "$object"
+
+  if test "$libtool" = yes; then
+    # Libtool generates 2 separate objects for the 2 libraries.  These
+    # two compilations output dependencies in $dir.libs/$base.o.d and
+    # in $dir$base.o.d.  We have to check for both files, because
+    # one of the two compilations can be disabled.  We should prefer
+    # $dir$base.o.d over $dir.libs/$base.o.d because the latter is
+    # automatically cleaned when .libs/ is deleted, while ignoring
+    # the former would cause a distcleancheck panic.
+    tmpdepfile1=$dir$base.o.d          # libtool 1.5
+    tmpdepfile2=$dir.libs/$base.o.d    # Likewise.
+    tmpdepfile3=$dir.libs/$base.d      # Compaq CCC V6.2-504
+    "$@" -Wc,-MD
+  else
+    tmpdepfile1=$dir$base.d
+    tmpdepfile2=$dir$base.d
+    tmpdepfile3=$dir$base.d
+    "$@" -MD
+  fi
+
+  stat=$?
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
+    exit $stat
+  fi
+
+  for tmpdepfile in "$tmpdepfile1" "$tmpdepfile2" "$tmpdepfile3"
+  do
+    test -f "$tmpdepfile" && break
+  done
+  # Same post-processing that is required for AIX mode.
+  aix_post_process_depfile
+  ;;
+
+msvc7)
+  if test "$libtool" = yes; then
+    showIncludes=-Wc,-showIncludes
+  else
+    showIncludes=-showIncludes
+  fi
+  "$@" $showIncludes > "$tmpdepfile"
+  stat=$?
+  grep -v '^Note: including file: ' "$tmpdepfile"
+  if test $stat -ne 0; then
+    rm -f "$tmpdepfile"
+    exit $stat
+  fi
+  rm -f "$depfile"
+  echo "$object : \\" > "$depfile"
+  # The first sed program below extracts the file names and escapes
+  # backslashes for cygpath.  The second sed program outputs the file
+  # name when reading, but also accumulates all include files in the
+  # hold buffer in order to output them again at the end.  This only
+  # works with sed implementations that can handle large buffers.
+  sed < "$tmpdepfile" -n '
+/^Note: including file:  *\(.*\)/ {
+  s//\1/
+  s/\\/\\\\/g
+  p
+}' | $cygpath_u | sort -u | sed -n '
+s/ /\\ /g
+s/\(.*\)/'"$tab"'\1 \\/p
+s/.\(.*\) \\/\1:/
+H
+$ {
+  s/.*/'"$tab"'/
+  G
+  p
+}' >> "$depfile"
+  echo >> "$depfile" # make sure the fragment doesn't end with a backslash
+  rm -f "$tmpdepfile"
+  ;;
+
+msvc7msys)
+  # This case exists only to let depend.m4 do its work.  It works by
+  # looking at the text of this script.  This case will never be run,
+  # since it is checked for above.
+  exit 1
+  ;;
+
+#nosideeffect)
+  # This comment above is used by automake to tell side-effect
+  # dependency tracking mechanisms from slower ones.
+
+dashmstdout)
+  # Important note: in order to support this mode, a compiler *must*
+  # always write the preprocessed file to stdout, regardless of -o.
+  "$@" || exit $?
+
+  # Remove the call to Libtool.
+  if test "$libtool" = yes; then
+    while test "X$1" != 'X--mode=compile'; do
+      shift
+    done
+    shift
+  fi
+
+  # Remove '-o $object'.
+  IFS=" "
+  for arg
+  do
+    case $arg in
+    -o)
+      shift
+      ;;
+    $object)
+      shift
+      ;;
+    *)
+      set fnord "$@" "$arg"
+      shift # fnord
+      shift # $arg
+      ;;
+    esac
+  done
+
+  test -z "$dashmflag" && dashmflag=-M
+  # Require at least two characters before searching for ':'
+  # in the target name.  This is to cope with DOS-style filenames:
+  # a dependency such as 'c:/foo/bar' could be seen as target 'c' otherwise.
+  "$@" $dashmflag |
+    sed "s|^[$tab ]*[^:$tab ][^:][^:]*:[$tab ]*|$object: |" > "$tmpdepfile"
+  rm -f "$depfile"
+  cat < "$tmpdepfile" > "$depfile"
+  # Some versions of the HPUX 10.20 sed can't process this sed invocation
+  # correctly.  Breaking it into two sed invocations is a workaround.
+  tr ' ' "$nl" < "$tmpdepfile" \
+    | sed -e 's/^\\$//' -e '/^$/d' -e '/:$/d' \
+    | sed -e 's/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+dashXmstdout)
+  # This case only exists to satisfy depend.m4.  It is never actually
+  # run, as this mode is specially recognized in the preamble.
+  exit 1
+  ;;
+
+makedepend)
+  "$@" || exit $?
+  # Remove any Libtool call
+  if test "$libtool" = yes; then
+    while test "X$1" != 'X--mode=compile'; do
+      shift
+    done
+    shift
+  fi
+  # X makedepend
+  shift
+  cleared=no eat=no
+  for arg
+  do
+    case $cleared in
+    no)
+      set ""; shift
+      cleared=yes ;;
+    esac
+    if test $eat = yes; then
+      eat=no
+      continue
+    fi
+    case "$arg" in
+    -D*|-I*)
+      set fnord "$@" "$arg"; shift ;;
+    # Strip any option that makedepend may not understand.  Remove
+    # the object too, otherwise makedepend will parse it as a source file.
+    -arch)
+      eat=yes ;;
+    -*|$object)
+      ;;
+    *)
+      set fnord "$@" "$arg"; shift ;;
+    esac
+  done
+  obj_suffix=`echo "$object" | sed 's/^.*\././'`
+  touch "$tmpdepfile"
+  ${MAKEDEPEND-makedepend} -o"$obj_suffix" -f"$tmpdepfile" "$@"
+  rm -f "$depfile"
+  # makedepend may prepend the VPATH from the source file name to the object.
+  # No need to regex-escape $object, excess matching of '.' is harmless.
+  sed "s|^.*\($object *:\)|\1|" "$tmpdepfile" > "$depfile"
+  # Some versions of the HPUX 10.20 sed can't process the last invocation
+  # correctly.  Breaking it into two sed invocations is a workaround.
+  sed '1,2d' "$tmpdepfile" \
+    | tr ' ' "$nl" \
+    | sed -e 's/^\\$//' -e '/^$/d' -e '/:$/d' \
+    | sed -e 's/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile" "$tmpdepfile".bak
+  ;;
+
+cpp)
+  # Important note: in order to support this mode, a compiler *must*
+  # always write the preprocessed file to stdout.
+  "$@" || exit $?
+
+  # Remove the call to Libtool.
+  if test "$libtool" = yes; then
+    while test "X$1" != 'X--mode=compile'; do
+      shift
+    done
+    shift
+  fi
+
+  # Remove '-o $object'.
+  IFS=" "
+  for arg
+  do
+    case $arg in
+    -o)
+      shift
+      ;;
+    $object)
+      shift
+      ;;
+    *)
+      set fnord "$@" "$arg"
+      shift # fnord
+      shift # $arg
+      ;;
+    esac
+  done
+
+  "$@" -E \
+    | sed -n -e '/^# [0-9][0-9]* "\([^"]*\)".*/ s:: \1 \\:p' \
+             -e '/^#line [0-9][0-9]* "\([^"]*\)".*/ s:: \1 \\:p' \
+    | sed '$ s: \\$::' > "$tmpdepfile"
+  rm -f "$depfile"
+  echo "$object : \\" > "$depfile"
+  cat < "$tmpdepfile" >> "$depfile"
+  sed < "$tmpdepfile" '/^$/d;s/^ //;s/ \\$//;s/$/ :/' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+msvisualcpp)
+  # Important note: in order to support this mode, a compiler *must*
+  # always write the preprocessed file to stdout.
+  "$@" || exit $?
+
+  # Remove the call to Libtool.
+  if test "$libtool" = yes; then
+    while test "X$1" != 'X--mode=compile'; do
+      shift
+    done
+    shift
+  fi
+
+  IFS=" "
+  for arg
+  do
+    case "$arg" in
+    -o)
+      shift
+      ;;
+    $object)
+      shift
+      ;;
+    "-Gm"|"/Gm"|"-Gi"|"/Gi"|"-ZI"|"/ZI")
+        set fnord "$@"
+        shift
+        shift
+        ;;
+    *)
+        set fnord "$@" "$arg"
+        shift
+        shift
+        ;;
+    esac
+  done
+  "$@" -E 2>/dev/null |
+  sed -n '/^#line [0-9][0-9]* "\([^"]*\)"/ s::\1:p' | $cygpath_u | sort -u > "$tmpdepfile"
+  rm -f "$depfile"
+  echo "$object : \\" > "$depfile"
+  sed < "$tmpdepfile" -n -e 's% %\\ %g' -e '/^\(.*\)$/ s::'"$tab"'\1 \\:p' >> "$depfile"
+  echo "$tab" >> "$depfile"
+  sed < "$tmpdepfile" -n -e 's% %\\ %g' -e '/^\(.*\)$/ s::\1\::p' >> "$depfile"
+  rm -f "$tmpdepfile"
+  ;;
+
+msvcmsys)
+  # This case exists only to let depend.m4 do its work.  It works by
+  # looking at the text of this script.  This case will never be run,
+  # since it is checked for above.
+  exit 1
+  ;;
+
+none)
+  exec "$@"
+  ;;
+
+*)
+  echo "Unknown depmode $depmode" 1>&2
+  exit 1
+  ;;
+esac
+
+exit 0
+
+# Local Variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
Index: /trunk/src/libs/libpng-1.6.45/example.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/example.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/example.c	(revision 107811)
@@ -0,0 +1,1041 @@
+
+#if 0 /* in case someone actually tries to compile this */
+
+/* example.c - an example of using libpng
+ *
+ * Maintained 2018-2024 Cosmin Truta
+ * Maintained 1998-2016 Glenn Randers-Pehrson
+ * Maintained 1996-1997 Andreas Dilger
+ * Written 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * To the extent possible under law, the authors have waived
+ * all copyright and related or neighboring rights to this file.
+ * This work is published from: United States, Canada.
+ */
+
+/* This is an example of how to use libpng to read and write PNG files.
+ * The file libpng-manual.txt is much more verbose then this.  If you have
+ * not read it, do so first.  This was designed to be a starting point of an
+ * implementation.  This is not officially part of libpng, is hereby placed
+ * in the public domain, and therefore does not require a copyright notice.
+ *
+ * This file does not currently compile, because it is missing certain
+ * parts, like allocating memory to hold an image.  You will have to
+ * supply these parts to get it to compile.  For an example of a minimal
+ * working PNG reader/writer, see pngtest.c, included in this distribution;
+ * see also the programs in the contrib directory.
+ */
+
+/* The simple, but restricted approach to reading a PNG file or data stream
+ * requires just two function calls, as in the following complete program.
+ * Writing a file needs just one function call, so long as the data has an
+ * appropriate layout.
+ *
+ * The following code reads PNG image data from a file and writes it, in a
+ * potentially new format, to a new file.  While this code will compile, there
+ * is minimal (insufficient) error checking.  For a more realistic version,
+ * see contrib/examples/pngtopng.c
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <png.h>
+#include <zlib.h>
+
+int main(int argc, const char **argv)
+{
+   if (argc == 3)
+   {
+      png_image image; /* The control structure used by libpng */
+
+      /* Initialize the 'png_image' structure. */
+      memset(&image, 0, (sizeof image));
+      image.version = PNG_IMAGE_VERSION;
+
+      /* The first argument is the file to read: */
+      if (png_image_begin_read_from_file(&image, argv[1]) != 0)
+      {
+         png_bytep buffer;
+
+         /* Set the format in which to read the PNG file; this code chooses a
+          * simple sRGB format with a non-associated alpha channel, adequate to
+          * store most images.
+          */
+         image.format = PNG_FORMAT_RGBA;
+
+         /* Now allocate enough memory to hold the image in this format; the
+          * PNG_IMAGE_SIZE macro uses the information about the image (width,
+          * height and format) stored in 'image'.
+          */
+         buffer = malloc(PNG_IMAGE_SIZE(image));
+
+         /* If enough memory was available, read the image in the desired
+          * format, then write the result out to the new file.  'background' is
+          * not necessary when reading the image, because the alpha channel is
+          * preserved; if it were to be removed, for example if we requested
+          * PNG_FORMAT_RGB, then either a solid background color would have to
+          * be supplied, or the output buffer would have to be initialized to
+          * the actual background of the image.
+          *
+          * The fourth argument to png_image_finish_read is the 'row_stride' -
+          * this is the number of components allocated for the image in each
+          * row.  It has to be at least as big as the value returned by
+          * PNG_IMAGE_ROW_STRIDE, but if you just allocate space for the
+          * default, minimum size, using PNG_IMAGE_SIZE as above, you can pass
+          * zero.
+          *
+          * The final argument is a pointer to a buffer for the colormap;
+          * colormaps have exactly the same format as a row of image pixels
+          * (so you choose what format to make the colormap by setting
+          * image.format).  A colormap is only returned if
+          * PNG_FORMAT_FLAG_COLORMAP is also set in image.format, so in this
+          * case NULL is passed as the final argument.  If you do want to force
+          * all images into an index/color-mapped format, then you can use:
+          *
+          *    PNG_IMAGE_COLORMAP_SIZE(image)
+          *
+          * to find the maximum size of the colormap in bytes.
+          */
+         if (buffer != NULL &&
+            png_image_finish_read(&image, NULL/*background*/, buffer,
+                0/*row_stride*/, NULL/*colormap*/) != 0)
+         {
+            /* Now write the image out to the second argument.  In the write
+             * call 'convert_to_8bit' allows 16-bit data to be squashed down to
+             * 8 bits; this isn't necessary here because the original read was
+             * to the 8-bit format.
+             */
+            if (png_image_write_to_file(&image, argv[2], 0/*convert_to_8bit*/,
+                buffer, 0/*row_stride*/, NULL/*colormap*/) != 0)
+            {
+               /* The image has been written successfully. */
+               exit(0);
+            }
+         }
+         else
+         {
+            /* Calling png_image_free is optional unless the simplified API was
+             * not run to completion.  In this case, if there wasn't enough
+             * memory for 'buffer', we didn't complete the read, so we must
+             * free the image:
+             */
+            if (buffer == NULL)
+               png_image_free(&image);
+            else
+               free(buffer);
+         }
+      }
+
+      /* Something went wrong reading or writing the image.  libpng stores a
+       * textual message in the 'png_image' structure:
+       */
+      fprintf(stderr, "pngtopng: error: %s\n", image.message);
+      exit(1);
+   }
+
+   fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n");
+   exit(2);
+}
+
+/* That's it ;-)  Of course you probably want to do more with PNG files than
+ * just converting them all to 32-bit RGBA PNG files; you can do that between
+ * the call to png_image_finish_read and png_image_write_to_file.  You can also
+ * ask for the image data to be presented in a number of different formats.
+ * You do this by simply changing the 'format' parameter set before allocating
+ * the buffer.
+ *
+ * The format parameter consists of five flags that define various aspects of
+ * the image.  You can simply add these together to get the format, or you can
+ * use one of the predefined macros from png.h (as above):
+ *
+ * PNG_FORMAT_FLAG_COLOR: if set, the image will have three color components
+ *    per pixel (red, green and blue); if not set, the image will just have one
+ *    luminance (grayscale) component.
+ *
+ * PNG_FORMAT_FLAG_ALPHA: if set, each pixel in the image will have an
+ *    additional alpha value; a linear value that describes the degree the
+ *    image pixel covers (overwrites) the contents of the existing pixel on the
+ *    display.
+ *
+ * PNG_FORMAT_FLAG_LINEAR: if set, the components of each pixel will be
+ *    returned as a series of 16-bit linear values; if not set, the components
+ *    will be returned as a series of 8-bit values encoded according to the
+ *    sRGB standard.  The 8-bit format is the normal format for images intended
+ *    for direct display, because almost all display devices do the inverse of
+ *    the sRGB transformation to the data they receive.  The 16-bit format is
+ *    more common for scientific data and image data that must be further
+ *    processed; because it is linear, simple math can be done on the component
+ *    values.  Regardless of the setting of this flag, the alpha channel is
+ *    always linear, although it will be 8 bits or 16 bits wide as specified by
+ *    the flag.
+ *
+ * PNG_FORMAT_FLAG_BGR: if set, the components of a color pixel will be
+ *    returned in the order blue, then green, then red.  If not set, the pixel
+ *    components are in the order red, then green, then blue.
+ *
+ * PNG_FORMAT_FLAG_AFIRST: if set, the alpha channel (if present) precedes the
+ *    color or grayscale components.  If not set, the alpha channel follows the
+ *    components.
+ *
+ * You do not have to read directly from a file.  You can read from memory or,
+ * on systems that support it, from a <stdio.h> FILE*.  This is controlled by
+ * the particular png_image_read_from_ function you call at the start.
+ * Likewise, on write, you can write to a FILE* if your system supports it.
+ * Check the macro PNG_STDIO_SUPPORTED to see if stdio support has been
+ * included in your libpng build.
+ *
+ * If you read 16-bit (PNG_FORMAT_FLAG_LINEAR) data, you may need to write it
+ * in the 8-bit format for display.  You do this by setting the convert_to_8bit
+ * flag to 'true'.
+ *
+ * Don't repeatedly convert between the 8-bit and 16-bit forms.  There is
+ * significant data loss when 16-bit data is converted to the 8-bit encoding,
+ * and the current libpng implementation of conversion to 16-bit is also
+ * significantly lossy.  The latter will be fixed in the future, but the former
+ * is unavoidable - the 8-bit format just doesn't have enough resolution.
+ */
+
+/* If your program needs more information from the PNG data it reads, or if you
+ * need to do more complex transformations, or minimize transformations, on the
+ * data you read, then you must use one of the several lower level libpng
+ * interfaces.
+ *
+ * All these interfaces require that you do your own error handling - your
+ * program must be able to arrange for control to return to your own code, any
+ * time libpng encounters a problem.  There are several ways to do this, but
+ * the standard way is to use the <setjmp.h> interface to establish a return
+ * point within your own code.  You must do this if you do not use the
+ * simplified interface (above).
+ *
+ * The first step is to include the header files you need, including the libpng
+ * header file.  Include any standard headers and feature test macros your
+ * program requires before including png.h:
+ */
+#include <png.h>
+
+ /* The png_jmpbuf() macro, used in error handling, became available in
+  * libpng version 1.0.6.  If you want to be able to run your code with older
+  * versions of libpng, you must define the macro yourself (but only if it
+  * is not already defined by libpng!)
+  */
+
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr) ((png_ptr)->png_jmpbuf)
+#endif
+
+/* Check to see if a file is a PNG file using png_sig_cmp().  png_sig_cmp()
+ * returns zero if the image is a PNG, and nonzero otherwise.
+ *
+ * The function check_if_png() shown here, but not used, returns nonzero (true)
+ * if the file can be opened and is a PNG, and 0 (false) otherwise.
+ *
+ * If this call is successful, and you are going to keep the file open,
+ * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
+ * you have created the png_ptr, so that libpng knows your application
+ * has read that many bytes from the start of the file.  Make sure you
+ * don't call png_set_sig_bytes() with more than 8 bytes read or give it
+ * an incorrect number of bytes read, or you will either have read too
+ * many bytes (your fault), or you are telling libpng to read the wrong
+ * number of magic bytes (also your fault).
+ *
+ * Many applications already read the first 2 or 4 bytes from the start
+ * of the image to determine the file type, so it would be easiest just
+ * to pass the bytes to png_sig_cmp(), or even skip that if you know
+ * you have a PNG file, and call png_set_sig_bytes().
+ */
+#define PNG_BYTES_TO_CHECK 4
+int check_if_png(char *file_name, FILE **fp)
+{
+   char buf[PNG_BYTES_TO_CHECK];
+
+   /* Open the prospective PNG file. */
+   if ((*fp = fopen(file_name, "rb")) == NULL)
+      return 0;
+
+   /* Read in some of the signature bytes. */
+   if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK)
+      return 0;
+
+   /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
+    * Return true if they match.
+    */
+   return png_sig_cmp(buf, 0, PNG_BYTES_TO_CHECK) == 0;
+}
+
+/* Read a PNG file.  You may want to return an error code if the read
+ * fails (depending upon the failure).  There are two "prototypes" given
+ * here - one where we are given the filename, and we need to open the
+ * file, and the other where we are given an open file (possibly with
+ * some or all of the magic bytes read - see comments above).
+ */
+#ifdef open_file /* prototype 1 */
+void read_png(char *file_name) /* We need to open the file */
+{
+   png_structp png_ptr;
+   png_infop info_ptr;
+   int sig_read = 0;
+   png_uint_32 width, height;
+   int bit_depth, color_type, interlace_type;
+   FILE *fp;
+
+   if ((fp = fopen(file_name, "rb")) == NULL)
+      return ERROR;
+
+#else no_open_file /* prototype 2 */
+void read_png(FILE *fp, int sig_read) /* File is already open */
+{
+   png_structp png_ptr;
+   png_infop info_ptr;
+   png_uint_32 width, height;
+   int bit_depth, color_type, interlace_type;
+#endif no_open_file /* Only use one prototype! */
+
+   /* Create and initialize the png_struct with the desired error handler
+    * functions.  If you want to use the default stderr and longjump method,
+    * you can supply NULL for the last three parameters.  We also supply the
+    * the compiler header file version, so that we know if the application
+    * was compiled with a compatible version of the library.  REQUIRED.
+    */
+   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+       png_voidp user_error_ptr, user_error_fn, user_warning_fn);
+
+   if (png_ptr == NULL)
+   {
+      fclose(fp);
+      return ERROR;
+   }
+
+   /* Allocate/initialize the memory for image information.  REQUIRED. */
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+   {
+      fclose(fp);
+      png_destroy_read_struct(&png_ptr, NULL, NULL);
+      return ERROR;
+   }
+
+   /* Set error handling if you are using the setjmp/longjmp method (this is
+    * the normal method of doing things with libpng).  REQUIRED unless you
+    * set up your own error handlers in the png_create_read_struct() earlier.
+    */
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      /* Free all of the memory associated with the png_ptr and info_ptr. */
+      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+      fclose(fp);
+      /* If we get here, we had a problem reading the file. */
+      return ERROR;
+   }
+
+   /* One of the following I/O initialization methods is REQUIRED. */
+#ifdef streams /* PNG file I/O method 1 */
+   /* Set up the input control if you are using standard C streams. */
+   png_init_io(png_ptr, fp);
+
+#else no_streams /* PNG file I/O method 2 */
+   /* If you are using replacement read functions, instead of calling
+    * png_init_io(), you would call:
+    */
+   png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
+   /* where user_io_ptr is a structure you want available to the callbacks. */
+#endif no_streams /* Use only one I/O method! */
+
+   /* If we have already read some of the signature */
+   png_set_sig_bytes(png_ptr, sig_read);
+
+#ifdef hilevel
+   /* If you have enough memory to read in the entire image at once,
+    * and you need to specify only transforms that can be controlled
+    * with one of the PNG_TRANSFORM_* bits (this presently excludes
+    * quantizing, filling, setting background, and doing gamma
+    * adjustment), then you can read the entire image (including
+    * pixels) into the info structure with this call:
+    */
+   png_read_png(png_ptr, info_ptr, png_transforms, NULL);
+
+#else
+   /* OK, you're doing it the hard way, with the lower-level functions. */
+
+   /* The call to png_read_info() gives us all of the information from the
+    * PNG file before the first IDAT (image data chunk).  REQUIRED.
+    */
+   png_read_info(png_ptr, info_ptr);
+
+   png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+       &interlace_type, NULL, NULL);
+
+   /* Set up the data transformations you want.  Note that these are all
+    * optional.  Only call them if you want/need them.  Many of the
+    * transformations only work on specific types of images, and many
+    * are mutually exclusive.
+    */
+
+   /* Tell libpng to strip 16 bits/color files down to 8 bits/color.
+    * Use accurate scaling if it's available, otherwise just chop off the
+    * low byte.
+    */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+   png_set_scale_16(png_ptr);
+#else
+   png_set_strip_16(png_ptr);
+#endif
+
+   /* Strip alpha bytes from the input data without combining with the
+    * background (not recommended).
+    */
+   png_set_strip_alpha(png_ptr);
+
+   /* Extract multiple pixels with bit depths of 1, 2 or 4 from a single
+    * byte into separate bytes (useful for paletted and grayscale images).
+    */
+   png_set_packing(png_ptr);
+
+   /* Change the order of packed pixels to least significant bit first
+    * (not useful if you are using png_set_packing).
+    */
+   png_set_packswap(png_ptr);
+
+   /* Expand paletted colors into true RGB triplets. */
+   if (color_type == PNG_COLOR_TYPE_PALETTE)
+      png_set_palette_to_rgb(png_ptr);
+
+   /* Expand grayscale images to the full 8 bits from 1, 2 or 4 bits/pixel. */
+   if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+      png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+   /* Expand paletted or RGB images with transparency to full alpha channels
+    * so the data will be available as RGBA quartets.
+    */
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) != 0)
+      png_set_tRNS_to_alpha(png_ptr);
+
+   /* Set the background color to draw transparent and alpha images over.
+    * It is possible to set the red, green and blue components directly
+    * for paletted images, instead of supplying a palette index.  Note that,
+    * even if the PNG file supplies a background, you are not required to
+    * use it - you should use the (solid) application background if it has one.
+    */
+   png_color_16 my_background, *image_background;
+
+   if (png_get_bKGD(png_ptr, info_ptr, &image_background) != 0)
+      png_set_background(png_ptr, image_background,
+          PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+   else
+      png_set_background(png_ptr, &my_background,
+          PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
+
+   /* Some suggestions as to how to get a screen gamma value.
+    *
+    * Note that screen gamma is the display_exponent, which includes
+    * the CRT_exponent and any correction for viewing conditions.
+    */
+   if (/* We have a user-defined screen gamma value */)
+      screen_gamma = user-defined screen_gamma;
+   /* This is one way that applications share the same screen gamma value. */
+   else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL)
+      screen_gamma = atof(gamma_str);
+   /* If we don't have another value */
+   else
+   {
+      screen_gamma = PNG_DEFAULT_sRGB; /* A good guess for a PC monitor
+                                          in a dimly lit room */
+      screen_gamma = PNG_GAMMA_MAC_18 or 1.0; /* Good guesses for Mac
+                                                 systems */
+   }
+
+   /* Tell libpng to handle the gamma conversion for you.  The final call
+    * is a good guess for PC generated images, but it should be configurable
+    * by the user at run time.  Gamma correction support in your application
+    * is strongly recommended.
+    */
+
+   int intent;
+
+   if (png_get_sRGB(png_ptr, info_ptr, &intent) != 0)
+      png_set_gamma(png_ptr, screen_gamma, PNG_DEFAULT_sRGB);
+   else
+   {
+      double image_gamma;
+      if (png_get_gAMA(png_ptr, info_ptr, &image_gamma) != 0)
+         png_set_gamma(png_ptr, screen_gamma, image_gamma);
+      else
+         png_set_gamma(png_ptr, screen_gamma, 0.45455);
+   }
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   /* Quantize RGB files down to 8-bit palette, or reduce palettes
+    * to the number of colors available on your screen.
+    */
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      int num_palette;
+      png_colorp palette;
+
+      /* This reduces the image to the application-supplied palette. */
+      if (/* We have our own palette */)
+      {
+         /* An array of colors to which the image should be quantized. */
+         png_color std_color_cube[MAX_SCREEN_COLORS];
+         png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
+             MAX_SCREEN_COLORS, NULL, 0);
+      }
+      /* This reduces the image to the palette supplied in the file. */
+      else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) != 0)
+      {
+         png_uint_16p histogram = NULL;
+         png_get_hIST(png_ptr, info_ptr, &histogram);
+         png_set_quantize(png_ptr, palette, num_palette,
+             max_screen_colors, histogram, 0);
+      }
+   }
+#endif /* READ_QUANTIZE */
+
+   /* Invert monochrome files to have 0 as white and 1 as black. */
+   png_set_invert_mono(png_ptr);
+
+   /* If you want to shift the pixel values from the range [0,255] or
+    * [0,65535] to the original [0,7] or [0,31], or whatever range the
+    * colors were originally in:
+    */
+   if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT) != 0)
+   {
+      png_color_8p sig_bit_p;
+      png_get_sBIT(png_ptr, info_ptr, &sig_bit_p);
+      png_set_shift(png_ptr, sig_bit_p);
+   }
+
+   /* Flip the RGB pixels to BGR (or RGBA to BGRA). */
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+      png_set_bgr(png_ptr);
+
+   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR). */
+   png_set_swap_alpha(png_ptr);
+
+   /* Swap bytes of 16-bit files to least significant byte first. */
+   png_set_swap(png_ptr);
+
+   /* Add filler (or alpha) byte (before/after each RGB triplet). */
+   png_set_filler(png_ptr, 0xffff, PNG_FILLER_AFTER);
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* Turn on interlace handling.  REQUIRED if you are not using
+    * png_read_image().  To see how to handle interlacing passes,
+    * see the png_read_row() method below:
+    */
+   number_passes = png_set_interlace_handling(png_ptr);
+#else /* !READ_INTERLACING */
+   number_passes = 1;
+#endif /* READ_INTERLACING */
+
+   /* Optional call to gamma correct and add the background to the palette
+    * and update info structure.  REQUIRED if you are expecting libpng to
+    * update the palette for you (i.e. you selected such a transform above).
+    */
+   png_read_update_info(png_ptr, info_ptr);
+
+   /* Allocate the memory to hold the image using the fields of info_ptr. */
+   png_bytep row_pointers[height];
+   for (row = 0; row < height; row++)
+      row_pointers[row] = NULL; /* Clear the pointer array */
+   for (row = 0; row < height; row++)
+      row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
+          info_ptr));
+
+   /* Now it's time to read the image.  One of these methods is REQUIRED. */
+#ifdef entire /* Read the entire image in one go */
+   png_read_image(png_ptr, row_pointers);
+
+#else no_entire /* Read the image one or more scanlines at a time */
+   /* The other way to read images - deal with interlacing: */
+   for (pass = 0; pass < number_passes; pass++)
+   {
+#ifdef single /* Read the image a single row at a time */
+      for (y = 0; y < height; y++)
+         png_read_rows(png_ptr, &row_pointers[y], NULL, 1);
+
+#else no_single /* Read the image several rows at a time */
+      for (y = 0; y < height; y += number_of_rows)
+      {
+#ifdef sparkle /* Read the image using the "sparkle" effect. */
+         png_read_rows(png_ptr, &row_pointers[y], NULL,
+             number_of_rows);
+#else no_sparkle /* Read the image using the "rectangle" effect */
+         png_read_rows(png_ptr, NULL, &row_pointers[y],
+             number_of_rows);
+#endif no_sparkle /* Use only one of these two methods */
+      }
+
+      /* If you want to display the image after every pass, do so here. */
+#endif no_single /* Use only one of these two methods */
+   }
+#endif no_entire /* Use only one of these two methods */
+
+   /* Read rest of file, and get additional chunks in info_ptr.  REQUIRED. */
+   png_read_end(png_ptr, info_ptr);
+#endif hilevel
+
+   /* At this point you have read the entire image. */
+
+   /* Clean up after the read, and free any memory allocated.  REQUIRED. */
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+   /* Close the file. */
+   fclose(fp);
+
+   /* That's it! */
+   return OK;
+}
+
+/* Progressively read a file */
+
+int
+initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
+{
+   /* Create and initialize the png_struct with the desired error handler
+    * functions.  If you want to use the default stderr and longjump method,
+    * you can supply NULL for the last three parameters.  We also check that
+    * the library version is compatible, in case we are using dynamically
+    * linked libraries.
+    */
+   *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+        png_voidp user_error_ptr, user_error_fn, user_warning_fn);
+   if (*png_ptr == NULL)
+   {
+      *info_ptr = NULL;
+      return ERROR;
+   }
+   *info_ptr = png_create_info_struct(png_ptr);
+   if (*info_ptr == NULL)
+   {
+      png_destroy_read_struct(png_ptr, info_ptr, NULL);
+      return ERROR;
+   }
+   if (setjmp(png_jmpbuf((*png_ptr))))
+   {
+      png_destroy_read_struct(png_ptr, info_ptr, NULL);
+      return ERROR;
+   }
+
+   /* You will need to provide all three function callbacks,
+    * even if you aren't using all of them.
+    * If you aren't using all functions, you can specify NULL
+    * parameters.  Even when all three functions are NULL,
+    * you need to call png_set_progressive_read_fn().
+    * These functions shouldn't be dependent on global or
+    * static variables if you are decoding several images
+    * simultaneously.  You should store stream specific data
+    * in a separate struct, given as the second parameter,
+    * and retrieve the pointer from inside the callbacks using
+    * the function png_get_progressive_ptr(png_ptr).
+    */
+   png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
+       info_callback, row_callback, end_callback);
+   return OK;
+}
+
+int
+process_data(png_structp *png_ptr, png_infop *info_ptr,
+    png_bytep buffer, png_uint_32 length)
+{
+   if (setjmp(png_jmpbuf((*png_ptr))))
+   {
+      /* Free the png_ptr and info_ptr memory on error. */
+      png_destroy_read_struct(png_ptr, info_ptr, NULL);
+      return ERROR;
+   }
+
+   /* Give chunks of data as they arrive from the data stream
+    * (in order, of course).
+    * On segmented machines, don't give it any more than 64K.
+    * The library seems to run fine with sizes of 4K, although
+    * you can give it much less if necessary. (I assume you can
+    * give it chunks of 1 byte, but I haven't tried with less
+    * than 256 bytes yet.)  When this function returns, you may
+    * want to display any rows that were generated in the row
+    * callback, if you aren't already displaying them there.
+    */
+   png_process_data(*png_ptr, *info_ptr, buffer, length);
+   return OK;
+}
+
+info_callback(png_structp png_ptr, png_infop info)
+{
+   /* Do any setup here, including setting any of the transformations
+    * mentioned in the Reading PNG files section.  For now, you _must_
+    * call either png_start_read_image() or png_read_update_info()
+    * after all the transformations are set (even if you don't set
+    * any).  You may start getting rows before png_process_data()
+    * returns, so this is your last chance to prepare for that.
+    */
+}
+
+row_callback(png_structp png_ptr, png_bytep new_row,
+    png_uint_32 row_num, int pass)
+{
+   /* This function is called for every row in the image.  If the
+    * image is interlaced, and you turned on the interlace handler,
+    * this function will be called for every row in every pass.
+    *
+    * In this function you will receive a pointer to new row data from
+    * libpng called new_row that is to replace a corresponding row (of
+    * the same data format) in a buffer allocated by your application.
+    *
+    * The new row data pointer "new_row" may be NULL, indicating there is
+    * no new data to be replaced (in cases of interlace loading).
+    *
+    * If new_row is not NULL, then you need to call
+    * png_progressive_combine_row(), to replace the corresponding row as
+    * shown below:
+    */
+
+   /* Get pointer to corresponding row in our PNG read buffer. */
+   png_bytep old_row = ((png_bytep *)our_data)[row_num];
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* If both rows are allocated, then copy the new row
+    * data to the corresponding row data.
+    */
+   if (old_row != NULL && new_row != NULL)
+      png_progressive_combine_row(png_ptr, old_row, new_row);
+
+   /* The rows and passes are called in order, so you don't really
+    * need the row_num and pass, but I'm supplying them because it
+    * may make your life easier.
+    *
+    * For the non-NULL rows of interlaced images, you must call
+    * png_progressive_combine_row() passing in the new row and the
+    * old row, as demonstrated above.  You can call this function for
+    * NULL rows (it will just return) and for non-interlaced images
+    * (it just does the memcpy for you) if it will make the code
+    * easier.  Thus, you can just do this for all cases:
+    */
+   png_progressive_combine_row(png_ptr, old_row, new_row);
+
+   /* where old_row is what was displayed for previous rows.  Note
+    * that the first pass (pass == 0 really) will completely cover
+    * the old row, so the rows do not have to be initialized.  After
+    * the first pass (and only for interlaced images), you will have
+    * to pass the current row as new_row, and the function will combine
+    * the old row and the new row.
+    */
+#endif /* READ_INTERLACING */
+}
+
+end_callback(png_structp png_ptr, png_infop info)
+{
+   /* This function is called when the whole image has been read,
+    * including any chunks after the image (up to and including
+    * the IEND).  You will usually have the same info chunk as you
+    * had in the header, although some data may have been added
+    * to the comments and time fields.
+    *
+    * Most people won't do much here, perhaps setting a flag that
+    * marks the image as finished.
+    */
+}
+
+/* Write a png file */
+void write_png(char *file_name /* , ... other image information ... */)
+{
+   FILE *fp;
+   png_structp png_ptr;
+   png_infop info_ptr;
+   png_colorp palette;
+
+   /* Open the file */
+   fp = fopen(file_name, "wb");
+   if (fp == NULL)
+      return ERROR;
+
+   /* Create and initialize the png_struct with the desired error handler
+    * functions.  If you want to use the default stderr and longjump method,
+    * you can supply NULL for the last three parameters.  We also check that
+    * the library version is compatible with the one used at compile time,
+    * in case we are using dynamically linked libraries.  REQUIRED.
+    */
+   png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+       png_voidp user_error_ptr, user_error_fn, user_warning_fn);
+   if (png_ptr == NULL)
+   {
+      fclose(fp);
+      return ERROR;
+   }
+
+   /* Allocate/initialize the image information data.  REQUIRED. */
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+   {
+      fclose(fp);
+      png_destroy_write_struct(&png_ptr,  NULL);
+      return ERROR;
+   }
+
+   /* Set up error handling.  REQUIRED if you aren't supplying your own
+    * error handling functions in the png_create_write_struct() call.
+    */
+   if (setjmp(png_jmpbuf(png_ptr)))
+   {
+      /* If we get here, we had a problem writing the file. */
+      fclose(fp);
+      png_destroy_write_struct(&png_ptr, &info_ptr);
+      return ERROR;
+   }
+
+   /* One of the following I/O initialization functions is REQUIRED. */
+
+#ifdef streams /* I/O initialization method 1 */
+   /* Set up the output control if you are using standard C streams. */
+   png_init_io(png_ptr, fp);
+
+#else no_streams /* I/O initialization method 2 */
+   /* If you are using replacement write functions, instead of calling
+    * png_init_io(), you would call:
+    */
+   png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
+       user_IO_flush_function);
+   /* where user_io_ptr is a structure you want available to the callbacks. */
+#endif no_streams /* Only use one initialization method */
+
+#ifdef hilevel
+   /* This is the easy way.  Use it if you already have all the
+    * image info living in the structure.  You could "|" many
+    * PNG_TRANSFORM flags into the png_transforms integer here.
+    */
+   png_write_png(png_ptr, info_ptr, png_transforms, NULL);
+
+#else
+   /* This is the hard way. */
+
+   /* Set the image information here.  Width and height are up to 2^31,
+    * bit_depth is one of 1, 2, 4, 8 or 16, but valid values also depend on
+    * the color_type selected.  color_type is one of PNG_COLOR_TYPE_GRAY,
+    * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB,
+    * or PNG_COLOR_TYPE_RGB_ALPHA.  interlace is either PNG_INTERLACE_NONE or
+    * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST
+    * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE.
+    * REQUIRED.
+    */
+   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
+       PNG_COLOR_TYPE_???, PNG_INTERLACE_????,
+       PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+   /* Set the palette if there is one.  REQUIRED for indexed-color images. */
+   palette = (png_colorp)png_malloc(png_ptr,
+       PNG_MAX_PALETTE_LENGTH * (sizeof (png_color)));
+   /* ... Set palette colors ... */
+   png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH);
+   /* You must not free palette here, because png_set_PLTE only makes a link
+    * to the palette that you allocated.  Wait until you are about to destroy
+    * the png structure.
+    */
+
+   /* Optional significant bit (sBIT) chunk. */
+   png_color_8 sig_bit;
+
+   /* If we are dealing with a grayscale image then */
+   sig_bit.gray = true_bit_depth;
+
+   /* Otherwise, if we are dealing with a color image then */
+   sig_bit.red = true_red_bit_depth;
+   sig_bit.green = true_green_bit_depth;
+   sig_bit.blue = true_blue_bit_depth;
+
+   /* If the image has an alpha channel then */
+   sig_bit.alpha = true_alpha_bit_depth;
+
+   png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+   /* Optional gamma chunk is strongly suggested if you have any guess
+    * as to the correct gamma of the image.
+    */
+   png_set_gAMA(png_ptr, info_ptr, gamma);
+
+   /* Optionally write comments into the image. */
+   {
+      png_text text_ptr[3];
+
+      char key0[] = "Title";
+      char text0[] = "Mona Lisa";
+      text_ptr[0].key = key0;
+      text_ptr[0].text = text0;
+      text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
+      text_ptr[0].itxt_length = 0;
+      text_ptr[0].lang = NULL;
+      text_ptr[0].lang_key = NULL;
+
+      char key1[] = "Author";
+      char text1[] = "Leonardo DaVinci";
+      text_ptr[1].key = key1;
+      text_ptr[1].text = text1;
+      text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
+      text_ptr[1].itxt_length = 0;
+      text_ptr[1].lang = NULL;
+      text_ptr[1].lang_key = NULL;
+
+      char key2[] = "Description";
+      char text2[] = "<long text>";
+      text_ptr[2].key = key2;
+      text_ptr[2].text = text2;
+      text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
+      text_ptr[2].itxt_length = 0;
+      text_ptr[2].lang = NULL;
+      text_ptr[2].lang_key = NULL;
+
+      png_set_text(write_ptr, write_info_ptr, text_ptr, 3);
+   }
+
+   /* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs. */
+
+   /* Note that if sRGB is present, the gAMA and cHRM chunks must be ignored
+    * on read and, if your application chooses to write them, they must
+    * be written in accordance with the sRGB profile.
+    */
+
+   /* Write the file header information.  REQUIRED. */
+   png_write_info(png_ptr, info_ptr);
+
+   /* If you want, you can write the info in two steps, in case you need to
+    * write your private chunk ahead of PLTE:
+    *
+    *   png_write_info_before_PLTE(write_ptr, write_info_ptr);
+    *   write_my_chunk();
+    *   png_write_info(png_ptr, info_ptr);
+    *
+    * However, given the level of known- and unknown-chunk support in 1.2.0
+    * and up, this should no longer be necessary.
+    */
+
+   /* Once we write out the header, the compression type on the text
+    * chunk gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
+    * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
+    * at the end.
+    */
+
+   /* Set up the transformations you want.  Note that these are
+    * all optional.  Only call them if you want them.
+    */
+
+   /* Invert monochrome pixels. */
+   png_set_invert_mono(png_ptr);
+
+   /* Shift the pixels up to a legal bit depth and fill in
+    * as appropriate to correctly scale the image.
+    */
+   png_set_shift(png_ptr, &sig_bit);
+
+   /* Pack pixels into bytes. */
+   png_set_packing(png_ptr);
+
+   /* Swap location of alpha bytes from ARGB to RGBA. */
+   png_set_swap_alpha(png_ptr);
+
+   /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
+    * RGB (4 channels -> 3 channels).  The second parameter is not used.
+    */
+   png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+   /* Flip BGR pixels to RGB. */
+   png_set_bgr(png_ptr);
+
+   /* Swap bytes of 16-bit files to most significant byte first. */
+   png_set_swap(png_ptr);
+
+   /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats. */
+   png_set_packswap(png_ptr);
+
+   /* Turn on interlace handling if you are not using png_write_image(). */
+   if (interlacing != 0)
+      number_passes = png_set_interlace_handling(png_ptr);
+   else
+      number_passes = 1;
+
+   /* The easiest way to write the image (you may have a different memory
+    * layout, however, so choose what fits your needs best).  You need to
+    * use the first method if you aren't handling interlacing yourself.
+    */
+   png_uint_32 k, height, width;
+
+   /* In this example, "image" is a one-dimensional array of bytes. */
+
+   /* Guard against integer overflow. */
+   if (height > PNG_SIZE_MAX / (width * bytes_per_pixel))
+      png_error(png_ptr, "Image data buffer would be too large");
+
+   png_byte image[height * width * bytes_per_pixel];
+   png_bytep row_pointers[height];
+
+   if (height > PNG_UINT_32_MAX / (sizeof (png_bytep)))
+      png_error(png_ptr, "Image is too tall to process in memory");
+
+   /* Set up pointers into your "image" byte array. */
+   for (k = 0; k < height; k++)
+      row_pointers[k] = image + k * width * bytes_per_pixel;
+
+   /* One of the following output methods is REQUIRED. */
+
+#ifdef entire /* Write out the entire image data in one call */
+   png_write_image(png_ptr, row_pointers);
+
+   /* The other way to write the image - deal with interlacing. */
+
+#else no_entire /* Write out the image data by one or more scanlines */
+
+   /* The number of passes is either 1 for non-interlaced images,
+    * or 7 for interlaced images.
+    */
+   for (pass = 0; pass < number_passes; pass++)
+   {
+      /* Write a few rows at a time. */
+      png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows);
+
+      /* If you are only writing one row at a time, this works. */
+      for (y = 0; y < height; y++)
+         png_write_rows(png_ptr, &row_pointers[y], 1);
+   }
+#endif no_entire /* Use only one output method */
+
+   /* You can write optional chunks like tEXt, zTXt, and tIME at the end
+    * as well.  Shouldn't be necessary in 1.2.0 and up, as all the public
+    * chunks are supported, and you can use png_set_unknown_chunks() to
+    * register unknown chunks into the info structure to be written out.
+    */
+
+   /* It is REQUIRED to call this to finish writing the rest of the file. */
+   png_write_end(png_ptr, info_ptr);
+#endif hilevel
+
+   /* If you png_malloced a palette, free it here.
+    * (Don't free info_ptr->palette, as shown in versions 1.0.5m and earlier of
+    * this example; if libpng mallocs info_ptr->palette, libpng will free it).
+    * If you allocated it with malloc() instead of png_malloc(), use free()
+    * instead of png_free().
+    */
+   png_free(png_ptr, palette);
+   palette = NULL;
+
+   /* Similarly, if you png_malloced any data that you passed in with
+    * png_set_something(), such as a hist or trans array, free it here,
+    * when you can be sure that libpng is through with it.
+    */
+   png_free(png_ptr, trans);
+   trans = NULL;
+
+   /* Whenever you use png_free(), it is a good idea to set the pointer to
+    * NULL in case your application inadvertently tries to png_free() it
+    * again.  When png_free() sees a NULL it returns without action, avoiding
+    * the double-free problem.
+    */
+
+   /* Clean up after the write, and free any allocated memory. */
+   png_destroy_write_struct(&png_ptr, &info_ptr);
+
+   /* Close the file. */
+   fclose(fp);
+
+   /* That's it! */
+   return OK;
+}
+
+#endif /* if 0 */
Index: /trunk/src/libs/libpng-1.6.45/install-sh
===================================================================
--- /trunk/src/libs/libpng-1.6.45/install-sh	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/install-sh	(revision 107811)
@@ -0,0 +1,541 @@
+#!/bin/sh
+# install - install a program, script, or datafile
+
+scriptversion=2023-11-23.18; # UTC
+
+# This originates from X11R5 (mit/util/scripts/install.sh), which was
+# later released in X11R6 (xc/config/util/install.sh) with the
+# following copyright and license.
+#
+# Copyright (C) 1994 X Consortium
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to
+# deal in the Software without restriction, including without limitation the
+# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+# sell copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+# X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+# AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNEC-
+# TION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+# Except as contained in this notice, the name of the X Consortium shall not
+# be used in advertising or otherwise to promote the sale, use or other deal-
+# ings in this Software without prior written authorization from the X Consor-
+# tium.
+#
+#
+# FSF changes to this file are in the public domain.
+#
+# Calling this script install-sh is preferred over install.sh, to prevent
+# 'make' implicit rules from creating a file called install from it
+# when there is no Makefile.
+#
+# This script is compatible with the BSD install script, but was written
+# from scratch.
+
+tab='	'
+nl='
+'
+IFS=" $tab$nl"
+
+# Set DOITPROG to "echo" to test this script.
+
+doit=${DOITPROG-}
+doit_exec=${doit:-exec}
+
+# Put in absolute file names if you don't have them in your path;
+# or use environment vars.
+
+chgrpprog=${CHGRPPROG-chgrp}
+chmodprog=${CHMODPROG-chmod}
+chownprog=${CHOWNPROG-chown}
+cmpprog=${CMPPROG-cmp}
+cpprog=${CPPROG-cp}
+mkdirprog=${MKDIRPROG-mkdir}
+mvprog=${MVPROG-mv}
+rmprog=${RMPROG-rm}
+stripprog=${STRIPPROG-strip}
+
+posix_mkdir=
+
+# Desired mode of installed file.
+mode=0755
+
+# Create dirs (including intermediate dirs) using mode 755.
+# This is like GNU 'install' as of coreutils 8.32 (2020).
+mkdir_umask=22
+
+backupsuffix=
+chgrpcmd=
+chmodcmd=$chmodprog
+chowncmd=
+mvcmd=$mvprog
+rmcmd="$rmprog -f"
+stripcmd=
+
+src=
+dst=
+dir_arg=
+dst_arg=
+
+copy_on_change=false
+is_target_a_directory=possibly
+
+usage="\
+Usage: $0 [OPTION]... [-T] SRCFILE DSTFILE
+   or: $0 [OPTION]... SRCFILES... DIRECTORY
+   or: $0 [OPTION]... -t DIRECTORY SRCFILES...
+   or: $0 [OPTION]... -d DIRECTORIES...
+
+In the 1st form, copy SRCFILE to DSTFILE.
+In the 2nd and 3rd, copy all SRCFILES to DIRECTORY.
+In the 4th, create DIRECTORIES.
+
+Options:
+     --help     display this help and exit.
+     --version  display version info and exit.
+
+  -c            (ignored)
+  -C            install only if different (preserve data modification time)
+  -d            create directories instead of installing files.
+  -g GROUP      $chgrpprog installed files to GROUP.
+  -m MODE       $chmodprog installed files to MODE.
+  -o USER       $chownprog installed files to USER.
+  -p            pass -p to $cpprog.
+  -s            $stripprog installed files.
+  -S SUFFIX     attempt to back up existing files, with suffix SUFFIX.
+  -t DIRECTORY  install into DIRECTORY.
+  -T            report an error if DSTFILE is a directory.
+
+Environment variables override the default commands:
+  CHGRPPROG CHMODPROG CHOWNPROG CMPPROG CPPROG MKDIRPROG MVPROG
+  RMPROG STRIPPROG
+
+By default, rm is invoked with -f; when overridden with RMPROG,
+it's up to you to specify -f if you want it.
+
+If -S is not specified, no backups are attempted.
+
+Report bugs to <bug-automake@gnu.org>.
+GNU Automake home page: <https://www.gnu.org/software/automake/>.
+General help using GNU software: <https://www.gnu.org/gethelp/>."
+
+while test $# -ne 0; do
+  case $1 in
+    -c) ;;
+
+    -C) copy_on_change=true;;
+
+    -d) dir_arg=true;;
+
+    -g) chgrpcmd="$chgrpprog $2"
+        shift;;
+
+    --help) echo "$usage"; exit $?;;
+
+    -m) mode=$2
+        case $mode in
+          *' '* | *"$tab"* | *"$nl"* | *'*'* | *'?'* | *'['*)
+            echo "$0: invalid mode: $mode" >&2
+            exit 1;;
+        esac
+        shift;;
+
+    -o) chowncmd="$chownprog $2"
+        shift;;
+
+    -p) cpprog="$cpprog -p";;
+
+    -s) stripcmd=$stripprog;;
+
+    -S) backupsuffix="$2"
+        shift;;
+
+    -t)
+        is_target_a_directory=always
+        dst_arg=$2
+        # Protect names problematic for 'test' and other utilities.
+        case $dst_arg in
+          -* | [=\(\)!]) dst_arg=./$dst_arg;;
+        esac
+        shift;;
+
+    -T) is_target_a_directory=never;;
+
+    --version) echo "$0 $scriptversion"; exit $?;;
+
+    --) shift
+        break;;
+
+    -*) echo "$0: invalid option: $1" >&2
+        exit 1;;
+
+    *)  break;;
+  esac
+  shift
+done
+
+# We allow the use of options -d and -T together, by making -d
+# take the precedence; this is for compatibility with GNU install.
+
+if test -n "$dir_arg"; then
+  if test -n "$dst_arg"; then
+    echo "$0: target directory not allowed when installing a directory." >&2
+    exit 1
+  fi
+fi
+
+if test $# -ne 0 && test -z "$dir_arg$dst_arg"; then
+  # When -d is used, all remaining arguments are directories to create.
+  # When -t is used, the destination is already specified.
+  # Otherwise, the last argument is the destination.  Remove it from $@.
+  for arg
+  do
+    if test -n "$dst_arg"; then
+      # $@ is not empty: it contains at least $arg.
+      set fnord "$@" "$dst_arg"
+      shift # fnord
+    fi
+    shift # arg
+    dst_arg=$arg
+    # Protect names problematic for 'test' and other utilities.
+    case $dst_arg in
+      -* | [=\(\)!]) dst_arg=./$dst_arg;;
+    esac
+  done
+fi
+
+if test $# -eq 0; then
+  if test -z "$dir_arg"; then
+    echo "$0: no input file specified." >&2
+    exit 1
+  fi
+  # It's OK to call 'install-sh -d' without argument.
+  # This can happen when creating conditional directories.
+  exit 0
+fi
+
+if test -z "$dir_arg"; then
+  if test $# -gt 1 || test "$is_target_a_directory" = always; then
+    if test ! -d "$dst_arg"; then
+      echo "$0: $dst_arg: Is not a directory." >&2
+      exit 1
+    fi
+  fi
+fi
+
+if test -z "$dir_arg"; then
+  do_exit='(exit $ret); exit $ret'
+  trap "ret=129; $do_exit" 1
+  trap "ret=130; $do_exit" 2
+  trap "ret=141; $do_exit" 13
+  trap "ret=143; $do_exit" 15
+
+  # Set umask so as not to create temps with too-generous modes.
+  # However, 'strip' requires both read and write access to temps.
+  case $mode in
+    # Optimize common cases.
+    *644) cp_umask=133;;
+    *755) cp_umask=22;;
+
+    *[0-7])
+      if test -z "$stripcmd"; then
+        u_plus_rw=
+      else
+        u_plus_rw='% 200'
+      fi
+      cp_umask=`expr '(' 777 - $mode % 1000 ')' $u_plus_rw`;;
+    *)
+      if test -z "$stripcmd"; then
+        u_plus_rw=
+      else
+        u_plus_rw=,u+rw
+      fi
+      cp_umask=$mode$u_plus_rw;;
+  esac
+fi
+
+for src
+do
+  # Protect names problematic for 'test' and other utilities.
+  case $src in
+    -* | [=\(\)!]) src=./$src;;
+  esac
+
+  if test -n "$dir_arg"; then
+    dst=$src
+    dstdir=$dst
+    test -d "$dstdir"
+    dstdir_status=$?
+    # Don't chown directories that already exist.
+    if test $dstdir_status = 0; then
+      chowncmd=""
+    fi
+  else
+
+    # Waiting for this to be detected by the "$cpprog $src $dsttmp" command
+    # might cause directories to be created, which would be especially bad
+    # if $src (and thus $dsttmp) contains '*'.
+    if test ! -f "$src" && test ! -d "$src"; then
+      echo "$0: $src does not exist." >&2
+      exit 1
+    fi
+
+    if test -z "$dst_arg"; then
+      echo "$0: no destination specified." >&2
+      exit 1
+    fi
+    dst=$dst_arg
+
+    # If destination is a directory, append the input filename.
+    if test -d "$dst"; then
+      if test "$is_target_a_directory" = never; then
+        echo "$0: $dst_arg: Is a directory" >&2
+        exit 1
+      fi
+      dstdir=$dst
+      dstbase=`basename "$src"`
+      case $dst in
+	*/) dst=$dst$dstbase;;
+	*)  dst=$dst/$dstbase;;
+      esac
+      dstdir_status=0
+    else
+      dstdir=`dirname "$dst"`
+      test -d "$dstdir"
+      dstdir_status=$?
+    fi
+  fi
+
+  case $dstdir in
+    */) dstdirslash=$dstdir;;
+    *)  dstdirslash=$dstdir/;;
+  esac
+
+  obsolete_mkdir_used=false
+
+  if test $dstdir_status != 0; then
+    case $posix_mkdir in
+      '')
+        # With -d, create the new directory with the user-specified mode.
+        # Otherwise, rely on $mkdir_umask.
+        if test -n "$dir_arg"; then
+          mkdir_mode=-m$mode
+        else
+          mkdir_mode=
+        fi
+
+        posix_mkdir=false
+	# The $RANDOM variable is not portable (e.g., dash).  Use it
+	# here however when possible just to lower collision chance.
+	tmpdir=${TMPDIR-/tmp}/ins$RANDOM-$$
+
+	trap '
+	  ret=$?
+	  rmdir "$tmpdir/a/b" "$tmpdir/a" "$tmpdir" 2>/dev/null
+	  exit $ret
+	' 0
+
+	# Because "mkdir -p" follows existing symlinks and we likely work
+	# directly in world-writeable /tmp, make sure that the '$tmpdir'
+	# directory is successfully created first before we actually test
+	# 'mkdir -p'.
+	if (umask $mkdir_umask &&
+	    $mkdirprog $mkdir_mode "$tmpdir" &&
+	    exec $mkdirprog $mkdir_mode -p -- "$tmpdir/a/b") >/dev/null 2>&1
+	then
+	  if test -z "$dir_arg" || {
+	       # Check for POSIX incompatibilities with -m.
+	       # HP-UX 11.23 and IRIX 6.5 mkdir -m -p sets group- or
+	       # other-writable bit of parent directory when it shouldn't.
+	       # FreeBSD 6.1 mkdir -m -p sets mode of existing directory.
+	       test_tmpdir="$tmpdir/a"
+	       ls_ld_tmpdir=`ls -ld "$test_tmpdir"`
+	       case $ls_ld_tmpdir in
+		 d????-?r-*) different_mode=700;;
+		 d????-?--*) different_mode=755;;
+		 *) false;;
+	       esac &&
+	       $mkdirprog -m$different_mode -p -- "$test_tmpdir" && {
+		 ls_ld_tmpdir_1=`ls -ld "$test_tmpdir"`
+		 test "$ls_ld_tmpdir" = "$ls_ld_tmpdir_1"
+	       }
+	     }
+	  then posix_mkdir=:
+	  fi
+	  rmdir "$tmpdir/a/b" "$tmpdir/a" "$tmpdir"
+	else
+	  # Remove any dirs left behind by ancient mkdir implementations.
+	  rmdir ./$mkdir_mode ./-p ./-- "$tmpdir" 2>/dev/null
+	fi
+	trap '' 0;;
+    esac
+
+    if
+      $posix_mkdir && (
+        umask $mkdir_umask &&
+        $doit_exec $mkdirprog $mkdir_mode -p -- "$dstdir"
+      )
+    then :
+    else
+
+      # mkdir does not conform to POSIX,
+      # or it failed possibly due to a race condition.  Create the
+      # directory the slow way, step by step, checking for races as we go.
+
+      case $dstdir in
+        /*) prefix='/';;
+        [-=\(\)!]*) prefix='./';;
+        *)  prefix='';;
+      esac
+
+      oIFS=$IFS
+      IFS=/
+      set -f
+      set fnord $dstdir
+      shift
+      set +f
+      IFS=$oIFS
+
+      prefixes=
+
+      for d
+      do
+        test X"$d" = X && continue
+
+        prefix=$prefix$d
+        if test -d "$prefix"; then
+          prefixes=
+        else
+          if $posix_mkdir; then
+            (umask $mkdir_umask &&
+             $doit_exec $mkdirprog $mkdir_mode -p -- "$dstdir") && break
+            # Don't fail if two instances are running concurrently.
+            test -d "$prefix" || exit 1
+          else
+            case $prefix in
+              *\'*) qprefix=`echo "$prefix" | sed "s/'/'\\\\\\\\''/g"`;;
+              *) qprefix=$prefix;;
+            esac
+            prefixes="$prefixes '$qprefix'"
+          fi
+        fi
+        prefix=$prefix/
+      done
+
+      if test -n "$prefixes"; then
+        # Don't fail if two instances are running concurrently.
+        (umask $mkdir_umask &&
+         eval "\$doit_exec \$mkdirprog $prefixes") ||
+          test -d "$dstdir" || exit 1
+        obsolete_mkdir_used=true
+      fi
+    fi
+  fi
+
+  if test -n "$dir_arg"; then
+    { test -z "$chowncmd" || $doit $chowncmd "$dst"; } &&
+    { test -z "$chgrpcmd" || $doit $chgrpcmd "$dst"; } &&
+    { test "$obsolete_mkdir_used$chowncmd$chgrpcmd" = false ||
+      test -z "$chmodcmd" || $doit $chmodcmd $mode "$dst"; } || exit 1
+  else
+
+    # Make a couple of temp file names in the proper directory.
+    dsttmp=${dstdirslash}_inst.$$_
+    rmtmp=${dstdirslash}_rm.$$_
+
+    # Trap to clean up those temp files at exit.
+    trap 'ret=$?; rm -f "$dsttmp" "$rmtmp" && exit $ret' 0
+
+    # Copy the file name to the temp name.
+    (umask $cp_umask &&
+     { test -z "$stripcmd" || {
+	 # Create $dsttmp read-write so that cp doesn't create it read-only,
+	 # which would cause strip to fail.
+	 if test -z "$doit"; then
+	   : >"$dsttmp" # No need to fork-exec 'touch'.
+	 else
+	   $doit touch "$dsttmp"
+	 fi
+       }
+     } &&
+     $doit_exec $cpprog "$src" "$dsttmp") &&
+
+    # and set any options; do chmod last to preserve setuid bits.
+    #
+    # If any of these fail, we abort the whole thing.  If we want to
+    # ignore errors from any of these, just make sure not to ignore
+    # errors from the above "$doit $cpprog $src $dsttmp" command.
+    #
+    { test -z "$chowncmd" || $doit $chowncmd "$dsttmp"; } &&
+    { test -z "$chgrpcmd" || $doit $chgrpcmd "$dsttmp"; } &&
+    { test -z "$stripcmd" || $doit $stripcmd "$dsttmp"; } &&
+    { test -z "$chmodcmd" || $doit $chmodcmd $mode "$dsttmp"; } &&
+
+    # If -C, don't bother to copy if it wouldn't change the file.
+    if $copy_on_change &&
+       old=`LC_ALL=C ls -dlL "$dst"     2>/dev/null` &&
+       new=`LC_ALL=C ls -dlL "$dsttmp"  2>/dev/null` &&
+       set -f &&
+       set X $old && old=:$2:$4:$5:$6 &&
+       set X $new && new=:$2:$4:$5:$6 &&
+       set +f &&
+       test "$old" = "$new" &&
+       $cmpprog "$dst" "$dsttmp" >/dev/null 2>&1
+    then
+      rm -f "$dsttmp"
+    else
+      # If $backupsuffix is set, and the file being installed
+      # already exists, attempt a backup.  Don't worry if it fails,
+      # e.g., if mv doesn't support -f.
+      if test -n "$backupsuffix" && test -f "$dst"; then
+        $doit $mvcmd -f "$dst" "$dst$backupsuffix" 2>/dev/null
+      fi
+
+      # Rename the file to the real destination.
+      $doit $mvcmd -f "$dsttmp" "$dst" 2>/dev/null ||
+
+      # The rename failed, perhaps because mv can't rename something else
+      # to itself, or perhaps because mv is so ancient that it does not
+      # support -f.
+      {
+        # Now remove or move aside any old file at destination location.
+        # We try this two ways since rm can't unlink itself on some
+        # systems and the destination file might be busy for other
+        # reasons.  In this case, the final cleanup might fail but the new
+        # file should still install successfully.
+        {
+          test ! -f "$dst" ||
+          $doit $rmcmd "$dst" 2>/dev/null ||
+          { $doit $mvcmd -f "$dst" "$rmtmp" 2>/dev/null &&
+            { $doit $rmcmd "$rmtmp" 2>/dev/null; :; }
+          } ||
+          { echo "$0: cannot unlink or rename $dst" >&2
+            (exit 1); exit 1
+          }
+        } &&
+
+        # Now rename the file to the real destination.
+        $doit $mvcmd "$dsttmp" "$dst"
+      }
+    fi || exit 1
+
+    trap '' 0
+  fi
+done
+
+# Local variables:
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
Index: /trunk/src/libs/libpng-1.6.45/intel/filter_sse2_intrinsics.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/intel/filter_sse2_intrinsics.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/intel/filter_sse2_intrinsics.c	(revision 107811)
@@ -0,0 +1,391 @@
+
+/* filter_sse2_intrinsics.c - SSE2 optimized filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2016-2017 Glenn Randers-Pehrson
+ * Written by Mike Klein and Matt Sarett
+ * Derived from arm/filter_neon_intrinsics.c
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_INTEL_SSE_IMPLEMENTATION > 0
+
+#include <immintrin.h>
+
+/* Functions in this file look at most 3 pixels (a,b,c) to predict the 4th (d).
+ * They're positioned like this:
+ *    prev:  c b
+ *    row:   a d
+ * The Sub filter predicts d=a, Avg d=(a+b)/2, and Paeth predicts d to be
+ * whichever of a, b, or c is closest to p=a+b-c.
+ */
+
+static __m128i load4(const void* p) {
+   int tmp;
+   memcpy(&tmp, p, sizeof(tmp));
+   return _mm_cvtsi32_si128(tmp);
+}
+
+static void store4(void* p, __m128i v) {
+   int tmp = _mm_cvtsi128_si32(v);
+   memcpy(p, &tmp, sizeof(int));
+}
+
+static __m128i load3(const void* p) {
+   png_uint_32 tmp = 0;
+   memcpy(&tmp, p, 3);
+   return _mm_cvtsi32_si128(tmp);
+}
+
+static void store3(void* p, __m128i v) {
+   int tmp = _mm_cvtsi128_si32(v);
+   memcpy(p, &tmp, 3);
+}
+
+void png_read_filter_row_sub3_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* The Sub filter predicts each pixel as the previous pixel, a.
+    * There is no pixel to the left of the first pixel.  It's encoded directly.
+    * That works with our main loop if we just say that left pixel was zero.
+    */
+   size_t rb;
+
+   __m128i a, d = _mm_setzero_si128();
+
+   png_debug(1, "in png_read_filter_row_sub3_sse2");
+
+   rb = row_info->rowbytes;
+   while (rb >= 4) {
+      a = d; d = load4(row);
+      d = _mm_add_epi8(d, a);
+      store3(row, d);
+
+      row += 3;
+      rb  -= 3;
+   }
+   if (rb > 0) {
+      a = d; d = load3(row);
+      d = _mm_add_epi8(d, a);
+      store3(row, d);
+
+      row += 3;
+      rb  -= 3;
+   }
+   PNG_UNUSED(prev)
+}
+
+void png_read_filter_row_sub4_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* The Sub filter predicts each pixel as the previous pixel, a.
+    * There is no pixel to the left of the first pixel.  It's encoded directly.
+    * That works with our main loop if we just say that left pixel was zero.
+    */
+   size_t rb;
+
+   __m128i a, d = _mm_setzero_si128();
+
+   png_debug(1, "in png_read_filter_row_sub4_sse2");
+
+   rb = row_info->rowbytes+4;
+   while (rb > 4) {
+      a = d; d = load4(row);
+      d = _mm_add_epi8(d, a);
+      store4(row, d);
+
+      row += 4;
+      rb  -= 4;
+   }
+   PNG_UNUSED(prev)
+}
+
+void png_read_filter_row_avg3_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* The Avg filter predicts each pixel as the (truncated) average of a and b.
+    * There's no pixel to the left of the first pixel.  Luckily, it's
+    * predicted to be half of the pixel above it.  So again, this works
+    * perfectly with our loop if we make sure a starts at zero.
+    */
+
+   size_t rb;
+
+   const __m128i zero = _mm_setzero_si128();
+
+   __m128i    b;
+   __m128i a, d = zero;
+
+   png_debug(1, "in png_read_filter_row_avg3_sse2");
+   rb = row_info->rowbytes;
+   while (rb >= 4) {
+      __m128i avg;
+             b = load4(prev);
+      a = d; d = load4(row );
+
+      /* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
+      avg = _mm_avg_epu8(a,b);
+      /* ...but we can fix it up by subtracting off 1 if it rounded up. */
+      avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
+                                            _mm_set1_epi8(1)));
+      d = _mm_add_epi8(d, avg);
+      store3(row, d);
+
+      prev += 3;
+      row  += 3;
+      rb   -= 3;
+   }
+   if (rb > 0) {
+      __m128i avg;
+             b = load3(prev);
+      a = d; d = load3(row );
+
+      /* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
+      avg = _mm_avg_epu8(a,b);
+      /* ...but we can fix it up by subtracting off 1 if it rounded up. */
+      avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
+                                            _mm_set1_epi8(1)));
+
+      d = _mm_add_epi8(d, avg);
+      store3(row, d);
+
+      prev += 3;
+      row  += 3;
+      rb   -= 3;
+   }
+}
+
+void png_read_filter_row_avg4_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* The Avg filter predicts each pixel as the (truncated) average of a and b.
+    * There's no pixel to the left of the first pixel.  Luckily, it's
+    * predicted to be half of the pixel above it.  So again, this works
+    * perfectly with our loop if we make sure a starts at zero.
+    */
+   size_t rb;
+   const __m128i zero = _mm_setzero_si128();
+   __m128i    b;
+   __m128i a, d = zero;
+
+   png_debug(1, "in png_read_filter_row_avg4_sse2");
+
+   rb = row_info->rowbytes+4;
+   while (rb > 4) {
+      __m128i avg;
+             b = load4(prev);
+      a = d; d = load4(row );
+
+      /* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
+      avg = _mm_avg_epu8(a,b);
+      /* ...but we can fix it up by subtracting off 1 if it rounded up. */
+      avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
+                                            _mm_set1_epi8(1)));
+
+      d = _mm_add_epi8(d, avg);
+      store4(row, d);
+
+      prev += 4;
+      row  += 4;
+      rb   -= 4;
+   }
+}
+
+/* Returns |x| for 16-bit lanes. */
+static __m128i abs_i16(__m128i x) {
+#if PNG_INTEL_SSE_IMPLEMENTATION >= 2
+   return _mm_abs_epi16(x);
+#else
+   /* Read this all as, return x<0 ? -x : x.
+   * To negate two's complement, you flip all the bits then add 1.
+    */
+   __m128i is_negative = _mm_cmplt_epi16(x, _mm_setzero_si128());
+
+   /* Flip negative lanes. */
+   x = _mm_xor_si128(x, is_negative);
+
+   /* +1 to negative lanes, else +0. */
+   x = _mm_sub_epi16(x, is_negative);
+   return x;
+#endif
+}
+
+/* Bytewise c ? t : e. */
+static __m128i if_then_else(__m128i c, __m128i t, __m128i e) {
+#if PNG_INTEL_SSE_IMPLEMENTATION >= 3
+   return _mm_blendv_epi8(e,t,c);
+#else
+   return _mm_or_si128(_mm_and_si128(c, t), _mm_andnot_si128(c, e));
+#endif
+}
+
+void png_read_filter_row_paeth3_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* Paeth tries to predict pixel d using the pixel to the left of it, a,
+    * and two pixels from the previous row, b and c:
+    *   prev: c b
+    *   row:  a d
+    * The Paeth function predicts d to be whichever of a, b, or c is nearest to
+    * p=a+b-c.
+    *
+    * The first pixel has no left context, and so uses an Up filter, p = b.
+    * This works naturally with our main loop's p = a+b-c if we force a and c
+    * to zero.
+    * Here we zero b and d, which become c and a respectively at the start of
+    * the loop.
+    */
+   size_t rb;
+   const __m128i zero = _mm_setzero_si128();
+   __m128i c, b = zero,
+           a, d = zero;
+
+   png_debug(1, "in png_read_filter_row_paeth3_sse2");
+
+   rb = row_info->rowbytes;
+   while (rb >= 4) {
+      /* It's easiest to do this math (particularly, deal with pc) with 16-bit
+       * intermediates.
+       */
+      __m128i pa,pb,pc,smallest,nearest;
+      c = b; b = _mm_unpacklo_epi8(load4(prev), zero);
+      a = d; d = _mm_unpacklo_epi8(load4(row ), zero);
+
+      /* (p-a) == (a+b-c - a) == (b-c) */
+
+      pa = _mm_sub_epi16(b,c);
+
+      /* (p-b) == (a+b-c - b) == (a-c) */
+      pb = _mm_sub_epi16(a,c);
+
+      /* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
+      pc = _mm_add_epi16(pa,pb);
+
+      pa = abs_i16(pa);  /* |p-a| */
+      pb = abs_i16(pb);  /* |p-b| */
+      pc = abs_i16(pc);  /* |p-c| */
+
+      smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
+
+      /* Paeth breaks ties favoring a over b over c. */
+      nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
+                 if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
+                                                             c));
+
+      /* Note `_epi8`: we need addition to wrap modulo 255. */
+      d = _mm_add_epi8(d, nearest);
+      store3(row, _mm_packus_epi16(d,d));
+
+      prev += 3;
+      row  += 3;
+      rb   -= 3;
+   }
+   if (rb > 0) {
+      /* It's easiest to do this math (particularly, deal with pc) with 16-bit
+       * intermediates.
+       */
+      __m128i pa,pb,pc,smallest,nearest;
+      c = b; b = _mm_unpacklo_epi8(load3(prev), zero);
+      a = d; d = _mm_unpacklo_epi8(load3(row ), zero);
+
+      /* (p-a) == (a+b-c - a) == (b-c) */
+      pa = _mm_sub_epi16(b,c);
+
+      /* (p-b) == (a+b-c - b) == (a-c) */
+      pb = _mm_sub_epi16(a,c);
+
+      /* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
+      pc = _mm_add_epi16(pa,pb);
+
+      pa = abs_i16(pa);  /* |p-a| */
+      pb = abs_i16(pb);  /* |p-b| */
+      pc = abs_i16(pc);  /* |p-c| */
+
+      smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
+
+      /* Paeth breaks ties favoring a over b over c. */
+      nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
+                         if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
+                                                                     c));
+
+      /* Note `_epi8`: we need addition to wrap modulo 255. */
+      d = _mm_add_epi8(d, nearest);
+      store3(row, _mm_packus_epi16(d,d));
+
+      prev += 3;
+      row  += 3;
+      rb   -= 3;
+   }
+}
+
+void png_read_filter_row_paeth4_sse2(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev)
+{
+   /* Paeth tries to predict pixel d using the pixel to the left of it, a,
+    * and two pixels from the previous row, b and c:
+    *   prev: c b
+    *   row:  a d
+    * The Paeth function predicts d to be whichever of a, b, or c is nearest to
+    * p=a+b-c.
+    *
+    * The first pixel has no left context, and so uses an Up filter, p = b.
+    * This works naturally with our main loop's p = a+b-c if we force a and c
+    * to zero.
+    * Here we zero b and d, which become c and a respectively at the start of
+    * the loop.
+    */
+   size_t rb;
+   const __m128i zero = _mm_setzero_si128();
+   __m128i pa,pb,pc,smallest,nearest;
+   __m128i c, b = zero,
+           a, d = zero;
+
+   png_debug(1, "in png_read_filter_row_paeth4_sse2");
+
+   rb = row_info->rowbytes+4;
+   while (rb > 4) {
+      /* It's easiest to do this math (particularly, deal with pc) with 16-bit
+       * intermediates.
+       */
+      c = b; b = _mm_unpacklo_epi8(load4(prev), zero);
+      a = d; d = _mm_unpacklo_epi8(load4(row ), zero);
+
+      /* (p-a) == (a+b-c - a) == (b-c) */
+      pa = _mm_sub_epi16(b,c);
+
+      /* (p-b) == (a+b-c - b) == (a-c) */
+      pb = _mm_sub_epi16(a,c);
+
+      /* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
+      pc = _mm_add_epi16(pa,pb);
+
+      pa = abs_i16(pa);  /* |p-a| */
+      pb = abs_i16(pb);  /* |p-b| */
+      pc = abs_i16(pc);  /* |p-c| */
+
+      smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
+
+      /* Paeth breaks ties favoring a over b over c. */
+      nearest  = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
+                         if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
+                                                                     c));
+
+      /* Note `_epi8`: we need addition to wrap modulo 255. */
+      d = _mm_add_epi8(d, nearest);
+      store4(row, _mm_packus_epi16(d,d));
+
+      prev += 4;
+      row  += 4;
+      rb   -= 4;
+   }
+}
+
+#endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/intel/intel_init.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/intel/intel_init.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/intel/intel_init.c	(revision 107811)
@@ -0,0 +1,52 @@
+
+/* intel_init.c - SSE2 optimized filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2016-2017 Glenn Randers-Pehrson
+ * Written by Mike Klein and Matt Sarett, Google, Inc.
+ * Derived from arm/arm_init.c
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+#if PNG_INTEL_SSE_IMPLEMENTATION > 0
+
+void
+png_init_filter_functions_sse2(png_structp pp, unsigned int bpp)
+{
+   /* The techniques used to implement each of these filters in SSE operate on
+    * one pixel at a time.
+    * So they generally speed up 3bpp images about 3x, 4bpp images about 4x.
+    * They can scale up to 6 and 8 bpp images and down to 2 bpp images,
+    * but they'd not likely have any benefit for 1bpp images.
+    * Most of these can be implemented using only MMX and 64-bit registers,
+    * but they end up a bit slower than using the equally-ubiquitous SSE2.
+   */
+   png_debug(1, "in png_init_filter_functions_sse2");
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth3_sse2;
+   }
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+          png_read_filter_row_paeth4_sse2;
+   }
+
+   /* No need optimize PNG_FILTER_VALUE_UP.  The compiler should
+    * autovectorize.
+    */
+}
+
+#endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */
+#endif /* PNG_READ_SUPPORTED */
Index: /trunk/src/libs/libpng-1.6.45/libpng-config.in
===================================================================
--- /trunk/src/libs/libpng-1.6.45/libpng-config.in	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/libpng-config.in	(revision 107811)
@@ -0,0 +1,127 @@
+#! /bin/sh
+
+# libpng-config
+# provides configuration info for libpng.
+
+# Copyright (C) 2002, 2004, 2006, 2007 Glenn Randers-Pehrson
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Modeled after libxml-config.
+
+version="@PNGLIB_VERSION@"
+prefix="@prefix@"
+exec_prefix="@exec_prefix@"
+libdir="@libdir@"
+includedir="@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
+libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
+all_libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ @LIBS@"
+I_opts="-I${includedir}"
+L_opts="-L${libdir}"
+R_opts=""
+cppflags=""
+ccopts=""
+ldopts=""
+
+usage()
+{
+    cat <<EOF
+Usage: $0 [OPTION] ...
+
+Known values for OPTION are:
+
+  --prefix        print libpng prefix
+  --libdir        print path to directory containing library
+  --libs          print library linking information
+  --ccopts        print compiler options
+  --cppflags      print pre-processor flags
+  --cflags        print preprocessor flags, I_opts, and compiler options
+  --I_opts        print "-I" include options
+  --L_opts        print linker "-L" flags for dynamic linking
+  --R_opts        print dynamic linker "-R" or "-rpath" flags
+  --ldopts        print linker options
+  --ldflags       print linker flags (ldopts, L_opts, R_opts, and libs)
+  --static        revise subsequent outputs for static linking
+  --help          print this help and exit
+  --version       print version information
+EOF
+
+    exit $1
+}
+
+if test $# -eq 0; then
+    usage 1
+fi
+
+while test $# -gt 0; do
+    case "$1" in
+
+    --prefix)
+        echo ${prefix}
+        ;;
+
+    --version)
+        echo ${version}
+        exit 0
+        ;;
+
+    --help)
+        usage 0
+        ;;
+
+    --ccopts)
+        echo ${ccopts}
+        ;;
+
+    --cppflags)
+        echo ${cppflags}
+        ;;
+
+    --cflags)
+        echo ${I_opts} ${cppflags} ${ccopts}
+        ;;
+
+    --libdir)
+        echo ${libdir}
+        ;;
+
+    --libs)
+        echo ${libs}
+        ;;
+
+    --I_opts)
+        echo ${I_opts}
+        ;;
+
+    --L_opts)
+        echo ${L_opts}
+        ;;
+
+    --R_opts)
+        echo ${R_opts}
+        ;;
+
+    --ldopts)
+        echo ${ldopts}
+        ;;
+
+    --ldflags)
+        echo ${ldopts} ${L_opts} ${R_opts} ${libs}
+        ;;
+
+    --static)
+        R_opts=""
+        libs=${all_libs}
+        ;;
+
+    *)
+        usage
+        exit 1
+        ;;
+    esac
+    shift
+done
+
+exit 0
Index: /trunk/src/libs/libpng-1.6.45/libpng-manual.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/libpng-manual.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/libpng-manual.txt	(revision 107811)
@@ -0,0 +1,5400 @@
+libpng-manual.txt - A description on how to use and modify libpng
+
+ Copyright (c) 2018-2024 Cosmin Truta
+ Copyright (c) 1998-2018 Glenn Randers-Pehrson
+
+ This document is released under the libpng license.
+ For conditions of distribution and use, see the disclaimer
+ and license in png.h
+
+ Based on:
+
+ libpng version 1.6.36, December 2018, through 1.6.43 - February 2024
+ Updated and distributed by Cosmin Truta
+ Copyright (c) 2018-2024 Cosmin Truta
+
+ libpng versions 0.97, January 1998, through 1.6.35 - July 2018
+ Updated and distributed by Glenn Randers-Pehrson
+ Copyright (c) 1998-2018 Glenn Randers-Pehrson
+
+ libpng 1.0 beta 6 - version 0.96 - May 28, 1997
+ Updated and distributed by Andreas Dilger
+ Copyright (c) 1996, 1997 Andreas Dilger
+
+ libpng 1.0 beta 2 - version 0.88 - January 26, 1996
+ For conditions of distribution and use, see copyright
+ notice in png.h. Copyright (c) 1995, 1996 Guy Eric
+ Schalnat, Group 42, Inc.
+
+ Updated/rewritten per request in the libpng FAQ
+ Copyright (c) 1995, 1996 Frank J. T. Wojcik
+ December 18, 1995 & January 20, 1996
+
+ TABLE OF CONTENTS
+
+    I. Introduction
+   II. Structures
+  III. Reading
+   IV. Writing
+    V. Simplified API
+   VI. Modifying/Customizing libpng
+  VII. MNG support
+ VIII. Changes to Libpng from version 0.88
+   IX. Changes to Libpng from version 1.0.x to 1.2.x
+    X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+   XI. Changes to Libpng from version 1.4.x to 1.5.x
+  XII. Changes to Libpng from version 1.5.x to 1.6.x
+ XIII. Detecting libpng
+  XIV. Source code repository
+   XV. Coding style
+
+I. Introduction
+
+This file describes how to use and modify the PNG reference library
+(known as libpng) for your own use.  In addition to this
+file, example.c is a good starting point for using the library, as
+it is heavily commented and should include everything most people
+will need.  We assume that libpng is already installed; see the
+INSTALL file for instructions on how to configure and install libpng.
+
+For examples of libpng usage, see the files "example.c", "pngtest.c",
+and the files in the "contrib" directory, all of which are included in
+the libpng distribution.
+
+Libpng was written as a companion to the PNG specification, as a way
+of reducing the amount of time and effort it takes to support the PNG
+file format in application programs.
+
+The PNG specification (second edition), November 2003, is available as
+a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
+<https://www.w3.org/TR/2003/REC-PNG-20031110/>.
+The W3C and ISO documents have identical technical content.
+
+The PNG-1.2 specification is available at
+<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
+It is technically equivalent
+to the PNG specification (second edition) but has some additional material.
+
+The PNG-1.0 specification is available as RFC 2083 at
+<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
+W3C Recommendation at <https://www.w3.org/TR/REC-png-961001>.
+
+Some additional chunks are described in the special-purpose public chunks
+documents at <http://www.libpng.org/pub/png/spec/register/>
+
+Other information
+about PNG, and the latest version of libpng, can be found at the PNG home
+page, <http://www.libpng.org/pub/png/>.
+
+Most users will not have to modify the library significantly; advanced
+users may want to modify it more.  All attempts were made to make it as
+complete as possible, while keeping the code easy to understand.
+Currently, this library only supports C.  Support for other languages
+is being considered.
+
+Libpng has been designed to handle multiple sessions at one time,
+to be easily modifiable, to be portable to the vast majority of
+machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
+to use.  The ultimate goal of libpng is to promote the acceptance of
+the PNG file format in whatever way possible.  While there is still
+work to be done (see the TODO file), libpng should cover the
+majority of the needs of its users.
+
+Libpng uses zlib for its compression and decompression of PNG files.
+Further information about zlib, and the latest version of zlib, can
+be found at the zlib home page, <https://zlib.net/>.
+The zlib compression utility is a general purpose utility that is
+useful for more than PNG files, and can be used without libpng.
+See the documentation delivered with zlib for more details.
+You can usually find the source files for the zlib utility wherever you
+find the libpng source files.
+
+Libpng is thread safe, provided the threads are using different
+instances of the structures.  Each thread should have its own
+png_struct and png_info instances, and thus its own image.
+Libpng does not protect itself against two threads using the
+same instance of a structure.
+
+II. Structures
+
+There are two main structures that are important to libpng, png_struct
+and png_info.  Both are internal structures that are no longer exposed
+in the libpng interface (as of libpng 1.5.0).
+
+The png_info structure is designed to provide information about the
+PNG file.  At one time, the fields of png_info were intended to be
+directly accessible to the user.  However, this tended to cause problems
+with applications using dynamically loaded libraries, and as a result
+a set of interface functions for png_info (the png_get_*() and png_set_*()
+functions) was developed, and direct access to the png_info fields was
+deprecated..
+
+The png_struct structure is the object used by the library to decode a
+single image.  As of 1.5.0 this structure is also not exposed.
+
+Almost all libpng APIs require a pointer to a png_struct as the first argument.
+Many (in particular the png_set and png_get APIs) also require a pointer
+to png_info as the second argument.  Some application visible macros
+defined in png.h designed for basic data access (reading and writing
+integers in the PNG format) don't take a png_info pointer, but it's almost
+always safe to assume that a (png_struct*) has to be passed to call an API
+function.
+
+You can have more than one png_info structure associated with an image,
+as illustrated in pngtest.c, one for information valid prior to the
+IDAT chunks and another (called "end_info" below) for things after them.
+
+The png.h header file is an invaluable reference for programming with libpng.
+And while I'm on the topic, make sure you include the libpng header file:
+
+#include <png.h>
+
+and also (as of libpng-1.5.0) the zlib header file, if you need it:
+
+#include <zlib.h>
+
+Types
+
+The png.h header file defines a number of integral types used by the
+APIs.  Most of these are fairly obvious; for example types corresponding
+to integers of particular sizes and types for passing color values.
+
+One exception is how non-integral numbers are handled.  For application
+convenience most APIs that take such numbers have C (double) arguments;
+however, internally PNG, and libpng, use 32 bit signed integers and encode
+the value by multiplying by 100,000.  As of libpng 1.5.0 a convenience
+macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
+which is simply (png_int_32).
+
+All APIs that take (double) arguments also have a matching API that
+takes the corresponding fixed point integer arguments.  The fixed point
+API has the same name as the floating point one with "_fixed" appended.
+The actual range of values permitted in the APIs is frequently less than
+the full range of (png_fixed_point) (-21474 to +21474).  When APIs require
+a non-negative argument the type is recorded as png_uint_32 above.  Consult
+the header file and the text below for more information.
+
+Special care must be take with sCAL chunk handling because the chunk itself
+uses non-integral values encoded as strings containing decimal floating point
+numbers.  See the comments in the header file.
+
+Configuration
+
+The main header file function declarations are frequently protected by C
+preprocessing directives of the form:
+
+    #ifdef PNG_feature_SUPPORTED
+    declare-function
+    #endif
+    ...
+    #ifdef PNG_feature_SUPPORTED
+    use-function
+    #endif
+
+The library can be built without support for these APIs, although a
+standard build will have all implemented APIs.  Application programs
+should check the feature macros before using an API for maximum
+portability.  From libpng 1.5.0 the feature macros set during the build
+of libpng are recorded in the header file "pnglibconf.h" and this file
+is always included by png.h.
+
+If you don't need to change the library configuration from the default, skip to
+the next section ("Reading").
+
+Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
+of the build project files in the 'projects' directory simply copy
+scripts/pnglibconf.h.prebuilt to pnglibconf.h.  This means that these build
+systems do not permit easy auto-configuration of the library - they only
+support the default configuration.
+
+The easiest way to make minor changes to the libpng configuration when
+auto-configuration is supported is to add definitions to the command line
+using (typically) CPPFLAGS.  For example:
+
+CPPFLAGS=-DPNG_NO_FLOATING_ARITHMETIC
+
+will change the internal libpng math implementation for gamma correction and
+other arithmetic calculations to fixed point, avoiding the need for fast
+floating point support.  The result can be seen in the generated pnglibconf.h -
+make sure it contains the changed feature macro setting.
+
+If you need to make more extensive configuration changes - more than one or two
+feature macro settings - you can either add -DPNG_USER_CONFIG to the build
+command line and put a list of feature macro settings in pngusr.h or you can set
+DFA_XTRA (a makefile variable) to a file containing the same information in the
+form of 'option' settings.
+
+A. Changing pnglibconf.h
+
+A variety of methods exist to build libpng.  Not all of these support
+reconfiguration of pnglibconf.h.  To reconfigure pnglibconf.h it must either be
+rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
+
+Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to
+pnglibconf.h and changing the lines defining the supported features, paying
+very close attention to the 'option' information in scripts/pnglibconf.dfa
+that describes those features and their requirements.  This is easy to get
+wrong.
+
+B. Configuration using DFA_XTRA
+
+Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
+variant such as 'nawk' or 'gawk', is available.  The configure build will
+automatically find an appropriate awk and build pnglibconf.h.
+The scripts/pnglibconf.mak file contains a set of make rules for doing the
+same thing if configure is not used, and many of the makefiles in the scripts
+directory use this approach.
+
+When rebuilding simply write a new file containing changed options and set
+DFA_XTRA to the name of this file.  This causes the build to append the new file
+to the end of scripts/pnglibconf.dfa.  The pngusr.dfa file should contain lines
+of the following forms:
+
+everything = off
+
+This turns all optional features off.  Include it at the start of pngusr.dfa to
+make it easier to build a minimal configuration.  You will need to turn at least
+some features on afterward to enable either reading or writing code, or both.
+
+option feature on
+option feature off
+
+Enable or disable a single feature.  This will automatically enable other
+features required by a feature that is turned on or disable other features that
+require a feature which is turned off.  Conflicting settings will cause an error
+message to be emitted by awk.
+
+setting feature default value
+
+Changes the default value of setting 'feature' to 'value'.  There are a small
+number of settings listed at the top of pnglibconf.h, they are documented in the
+source code.  Most of these values have performance implications for the library
+but most of them have no visible effect on the API.  Some can also be overridden
+from the API.
+
+This method of building a customized pnglibconf.h is illustrated in
+contrib/pngminim/*.  See the "$(PNGCONF):" target in the makefile and
+pngusr.dfa in these directories.
+
+C. Configuration using PNG_USER_CONFIG
+
+If -DPNG_USER_CONFIG is added to the CPPFLAGS when pnglibconf.h is built,
+the file pngusr.h will automatically be included before the options in
+scripts/pnglibconf.dfa are processed.  Your pngusr.h file should contain only
+macro definitions turning features on or off or setting settings.
+
+Apart from the global setting "everything = off" all the options listed above
+can be set using macros in pngusr.h:
+
+#define PNG_feature_SUPPORTED
+
+is equivalent to:
+
+option feature on
+
+#define PNG_NO_feature
+
+is equivalent to:
+
+option feature off
+
+#define PNG_feature value
+
+is equivalent to:
+
+setting feature default value
+
+Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
+pngusr file you supply override the contents of scripts/pnglibconf.dfa
+
+If confusing or incomprehensible behavior results it is possible to
+examine the intermediate file pnglibconf.dfn to find the full set of
+dependency information for each setting and option.  Simply locate the
+feature in the file and read the C comments that precede it.
+
+This method is also illustrated in the contrib/pngminim/* makefiles and
+pngusr.h.
+
+III. Reading
+
+We'll now walk you through the possible functions to call when reading
+in a PNG file sequentially, briefly explaining the syntax and purpose
+of each one.  See example.c and png.h for more detail.  While
+progressive reading is covered in the next section, you will still
+need some of the functions discussed in this section to read a PNG
+file.
+
+Setup
+
+You will want to do the I/O initialization(*) before you get into libpng,
+so if it doesn't work, you don't have much to undo.  Of course, you
+will also want to insure that you are, in fact, dealing with a PNG
+file.  Libpng provides a simple check to see if a file is a PNG file.
+To use it, pass in the first 1 to 8 bytes of the file to the function
+png_sig_cmp(), and it will return 0 (false) if the bytes match the
+corresponding bytes of the PNG signature, or nonzero (true) otherwise.
+Of course, the more bytes you pass in, the greater the accuracy of the
+prediction.
+
+If you are intending to keep the file pointer open for use in libpng,
+you must ensure you don't read more than 8 bytes from the beginning
+of the file, and you also have to make a call to png_set_sig_bytes()
+with the number of bytes you read from the beginning.  Libpng will
+then only check the bytes (if any) that your program didn't read.
+
+(*): If you are not using the standard I/O functions, you will need
+to replace them with custom functions.  See the discussion under
+Customizing libpng.
+
+    FILE *fp = fopen(file_name, "rb");
+    if (!fp)
+    {
+       return ERROR;
+    }
+
+    if (fread(header, 1, number, fp) != number)
+    {
+       return ERROR;
+    }
+
+    is_png = (png_sig_cmp(header, 0, number) == 0);
+    if (!is_png)
+    {
+       return NOT_PNG;
+    }
+
+Next, png_struct and png_info need to be allocated and initialized.  In
+order to ensure that the size of these structures is correct even with a
+dynamically linked libpng, there are functions to initialize and
+allocate the structures.  We also pass the library version, optional
+pointers to error handling functions, and a pointer to a data struct for
+use by the error functions, if necessary (the pointer and functions can
+be NULL if the default error handlers are to be used).  See the section
+on Changes to Libpng below regarding the old initialization functions.
+The structure allocation functions quietly return NULL if they fail to
+create the structure, so your application should check for that.
+
+    png_structp png_ptr = png_create_read_struct
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+       return ERROR;
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+    {
+       png_destroy_read_struct(&png_ptr, NULL, NULL);
+       return ERROR;
+    }
+
+If you want to use your own memory allocation routines,
+use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
+png_create_read_struct_2() instead of png_create_read_struct():
+
+    png_structp png_ptr = png_create_read_struct_2
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn, (png_voidp)
+        user_mem_ptr, user_malloc_fn, user_free_fn);
+
+The error handling routines passed to png_create_read_struct()
+and the memory alloc/free routines passed to png_create_struct_2()
+are only necessary if you are not using the libpng supplied error
+handling and memory alloc/free functions.
+
+When libpng encounters an error, it expects to longjmp back
+to your routine.  Therefore, you will need to call setjmp and pass
+your png_jmpbuf(png_ptr).  If you read the file from different
+routines, you will need to update the longjmp buffer every time you enter
+a new routine that will call a png_*() function.
+
+See your documentation of setjmp/longjmp for your compiler for more
+information on setjmp/longjmp.  See the discussion on libpng error
+handling in the Customizing Libpng section below for more information
+on the libpng error handling.  If an error occurs, and libpng longjmp's
+back to your setjmp, you will want to call png_destroy_read_struct() to
+free any memory.
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
+       fclose(fp);
+       return ERROR;
+    }
+
+Pass NULL instead of &end_info if you didn't create an end_info
+structure.
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Now you need to set up the input code.  The default for libpng is to
+use the C function fread().  If you use this, you will need to pass a
+valid FILE * in the function png_init_io().  Be sure that the file is
+opened in binary mode.  If you wish to handle reading data in another
+way, you need not call the png_init_io() function, but you must then
+implement the libpng I/O methods discussed in the Customizing Libpng
+section below.
+
+    png_init_io(png_ptr, fp);
+
+If you had previously opened the file and read any of the signature from
+the beginning in order to see if this was a PNG file, you need to let
+libpng know that there are some bytes missing from the start of the file.
+
+    png_set_sig_bytes(png_ptr, number);
+
+You can change the zlib compression buffer size to be used while
+reading compressed data with
+
+    png_set_compression_buffer_size(png_ptr, buffer_size);
+
+where the default size is 8192 bytes.  Note that the buffer size
+is changed immediately and the buffer is reallocated immediately,
+instead of setting a flag to be acted upon later.
+
+If you want CRC errors to be handled in a different manner than
+the default, use
+
+    png_set_crc_action(png_ptr, crit_action, ancil_action);
+
+The values for png_set_crc_action() say how libpng is to handle CRC errors in
+ancillary and critical chunks, and whether to use the data contained
+therein. Starting with libpng-1.6.26, this also governs how an ADLER32 error
+is handled while reading the IDAT chunk. Note that it is impossible to
+"discard" data in a critical chunk.
+
+Choices for (int) crit_action are
+   PNG_CRC_DEFAULT      0  error/quit
+   PNG_CRC_ERROR_QUIT   1  error/quit
+   PNG_CRC_WARN_USE     3  warn/use data
+   PNG_CRC_QUIET_USE    4  quiet/use data
+   PNG_CRC_NO_CHANGE    5  use the current value
+
+Choices for (int) ancil_action are
+   PNG_CRC_DEFAULT      0  error/quit
+   PNG_CRC_ERROR_QUIT   1  error/quit
+   PNG_CRC_WARN_DISCARD 2  warn/discard data
+   PNG_CRC_WARN_USE     3  warn/use data
+   PNG_CRC_QUIET_USE    4  quiet/use data
+   PNG_CRC_NO_CHANGE    5  use the current value
+
+When the setting for crit_action is PNG_CRC_QUIET_USE, the CRC and ADLER32
+checksums are not only ignored, but they are not evaluated.
+
+Setting up callback code
+
+You can set up a callback function to handle any unknown chunks in the
+input stream. You must supply the function
+
+    read_chunk_callback(png_structp png_ptr,
+         png_unknown_chunkp chunk)
+    {
+       /* The unknown chunk structure contains your
+          chunk data, along with similar data for any other
+          unknown chunks: */
+
+           png_byte name[5];
+           png_byte *data;
+           size_t size;
+
+       /* Note that libpng has already taken care of
+          the CRC handling */
+
+       /* put your code here.  Search for your chunk in the
+          unknown chunk structure, process it, and return one
+          of the following: */
+
+       return -n; /* chunk had an error */
+       return 0; /* did not recognize */
+       return n; /* success */
+    }
+
+(You can give your function another name that you like instead of
+"read_chunk_callback")
+
+To inform libpng about your function, use
+
+    png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
+        read_chunk_callback);
+
+This names not only the callback function, but also a user pointer that
+you can retrieve with
+
+    png_get_user_chunk_ptr(png_ptr);
+
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks which the callback does not handle will be saved when read.  You can
+cause them to be discarded by returning '1' ("handled") instead of '0'.  This
+behavior will change in libpng 1.7 and the default handling set by the
+png_set_keep_unknown_chunks() function, described below, will be used when the
+callback returns 0.  If you want the existing behavior you should set the global
+default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
+versions of libpng and with 1.7.  Libpng 1.6 issues a warning if you keep the
+default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.
+
+At this point, you can set up a callback function that will be
+called after each row has been read, which you can use to control
+a progress meter or the like.  It's demonstrated in pngtest.c.
+You must supply a function
+
+    void read_row_callback(png_structp png_ptr,
+       png_uint_32 row, int pass)
+    {
+       /* put your code here */
+    }
+
+(You can give it another name that you like instead of "read_row_callback")
+
+To inform libpng about your function, use
+
+    png_set_read_status_fn(png_ptr, read_row_callback);
+
+When this function is called the row has already been completely processed and
+the 'row' and 'pass' refer to the next row to be handled.  For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0.  For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes.  Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass-1'; if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+Unknown-chunk handling
+
+Now you get to set the way the library processes unknown chunks in the
+input PNG stream. Both known and unknown chunks will be read.  Normal
+behavior is that known chunks will be parsed into information in
+various info_ptr members while unknown chunks will be discarded. This
+behavior can be wasteful if your application will never use some known
+chunk types. To change this, you can call:
+
+    png_set_keep_unknown_chunks(png_ptr, keep,
+        chunk_list, num_chunks);
+
+    keep       - 0: default unknown chunk handling
+                 1: ignore; do not keep
+                 2: keep only if safe-to-copy
+                 3: keep even if unsafe-to-copy
+
+               You can use these definitions:
+                 PNG_HANDLE_CHUNK_AS_DEFAULT   0
+                 PNG_HANDLE_CHUNK_NEVER        1
+                 PNG_HANDLE_CHUNK_IF_SAFE      2
+                 PNG_HANDLE_CHUNK_ALWAYS       3
+
+    chunk_list - list of chunks affected (a byte string,
+                 five bytes per chunk, NULL or '\0' if
+                 num_chunks is positive; ignored if
+                 numchunks <= 0).
+
+    num_chunks - number of chunks affected; if 0, all
+                 unknown chunks are affected.  If positive,
+                 only the chunks in the list are affected,
+                 and if negative all unknown chunks and
+                 all known chunks except for the IHDR,
+                 PLTE, tRNS, IDAT, and IEND chunks are
+                 affected.
+
+Unknown chunks declared in this way will be saved as raw data onto a
+list of png_unknown_chunk structures.  If a chunk that is normally
+known to libpng is named in the list, it will be handled as unknown,
+according to the "keep" directive.  If a chunk is named in successive
+instances of png_set_keep_unknown_chunks(), the final instance will
+take precedence.  The IHDR and IEND chunks should not be named in
+chunk_list; if they are, libpng will process them normally anyway.
+If you know that your application will never make use of some particular
+chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below.
+
+Here is an example of the usage of png_set_keep_unknown_chunks(),
+where the private "vpAg" chunk will later be processed by a user chunk
+callback function:
+
+    png_byte vpAg[5]={118, 112,  65, 103, (png_byte) '\0'};
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      png_byte unused_chunks[]=
+      {
+        104,  73,  83,  84, (png_byte) '\0',   /* hIST */
+        105,  84,  88, 116, (png_byte) '\0',   /* iTXt */
+        112,  67,  65,  76, (png_byte) '\0',   /* pCAL */
+        115,  67,  65,  76, (png_byte) '\0',   /* sCAL */
+        115,  80,  76,  84, (png_byte) '\0',   /* sPLT */
+        116,  73,  77,  69, (png_byte) '\0',   /* tIME */
+      };
+    #endif
+
+    ...
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      /* ignore all unknown chunks
+       * (use global setting "2" for libpng16 and earlier):
+       */
+      png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);
+
+      /* except for vpAg: */
+      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
+
+      /* also ignore unused known chunks: */
+      png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
+         (int)(sizeof unused_chunks)/5);
+    #endif
+
+User limits
+
+The PNG specification allows the width and height of an image to be as
+large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
+For safety, libpng imposes a default limit of 1 million rows and columns.
+Larger images will be rejected immediately with a png_error() call. If
+you wish to change these limits, you can use
+
+   png_set_user_limits(png_ptr, width_max, height_max);
+
+to set your own limits (libpng may reject some very wide images
+anyway because of potential buffer overflow conditions).
+
+You should put this statement after you create the PNG structure and
+before calling png_read_info(), png_read_png(), or png_process_data().
+
+When writing a PNG datastream, put this statement before calling
+png_write_info() or png_write_png().
+
+If you need to retrieve the limits that are being applied, use
+
+   width_max = png_get_user_width_max(png_ptr);
+   height_max = png_get_user_height_max(png_ptr);
+
+The PNG specification sets no limit on the number of ancillary chunks
+allowed in a PNG datastream.  By default, libpng imposes a limit of
+a total of 1000 sPLT, tEXt, iTXt, zTXt, and unknown chunks to be stored.
+If you have set up both info_ptr and end_info_ptr, the limit applies
+separately to each.  You can change the limit on the total number of such
+chunks that will be stored, with
+
+   png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
+
+where 0x7fffffffL means unlimited.  You can retrieve this limit with
+
+   chunk_cache_max = png_get_chunk_cache_max(png_ptr);
+
+Libpng imposes a limit of 8 Megabytes (8,000,000 bytes) on the amount of
+memory that any chunk other than IDAT can occupy, originally or when
+decompressed (prior to libpng-1.6.32 the limit was only applied to compressed
+chunks after decompression). You can change this limit with
+
+   png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
+
+and you can retrieve the limit with
+
+   chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
+
+Any chunks that would cause either of these limits to be exceeded will
+be ignored.
+
+Information about your system
+
+If you intend to display the PNG or to incorporate it in other image data you
+need to tell libpng information about your display or drawing surface so that
+libpng can convert the values in the image to match the display.
+
+From libpng-1.5.4 this information can be set before reading the PNG file
+header.  In earlier versions png_set_gamma() existed but behaved incorrectly if
+called before the PNG file header had been read and png_set_alpha_mode() did not
+exist.
+
+If you need to support versions prior to libpng-1.5.4 test the version number
+as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures
+described in the appropriate manual page.
+
+You give libpng the encoding expected by your system expressed as a 'gamma'
+value.  You can also specify a default encoding for the PNG file in
+case the required information is missing from the file.  By default libpng
+assumes that the PNG data matches your system, to keep this default call:
+
+   png_set_gamma(png_ptr, screen_gamma, output_gamma);
+
+or you can use the fixed point equivalent:
+
+   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma,
+      PNG_FP_1*output_gamma);
+
+If you don't know the gamma for your system it is probably 2.2 - a good
+approximation to the IEC standard for display systems (sRGB).  If images are
+too contrasty or washed out you got the value wrong - check your system
+documentation!
+
+Many systems permit the system gamma to be changed via a lookup table in the
+display driver, a few systems, including older Macs, change the response by
+default.  As of 1.5.4 three special values are available to handle common
+situations:
+
+   PNG_DEFAULT_sRGB: Indicates that the system conforms to the
+                     IEC 61966-2-1 standard.  This matches almost
+                     all systems.
+   PNG_GAMMA_MAC_18: Indicates that the system is an older
+                     (pre Mac OS 10.6) Apple Macintosh system with
+                     the default settings.
+   PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates
+                     that the system expects data with no gamma
+                     encoding.
+
+You would use the linear (unencoded) value if you need to process the pixel
+values further because this avoids the need to decode and re-encode each
+component value whenever arithmetic is performed.  A lot of graphics software
+uses linear values for this reason, often with higher precision component values
+to preserve overall accuracy.
+
+
+The output_gamma value expresses how to decode the output values, not how
+they are encoded.  The values used correspond to the normal numbers used to
+describe the overall gamma of a computer display system; for example 2.2 for
+an sRGB conformant system.  The values are scaled by 100000 in the _fixed
+version of the API (so 220000 for sRGB.)
+
+The inverse of the value is always used to provide a default for the PNG file
+encoding if it has no gAMA chunk and if png_set_gamma() has not been called
+to override the PNG gamma information.
+
+When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
+opaque pixels however pixels with lower alpha values are not encoded,
+regardless of the output gamma setting.
+
+When the standard Porter Duff handling is requested with mode 1 the output
+encoding is set to be linear and the output_gamma value is only relevant
+as a default for input data that has no gamma information.  The linear output
+encoding will be overridden if png_set_gamma() is called - the results may be
+highly unexpected!
+
+The following numbers are derived from the sRGB standard and the research
+behind it.  sRGB is defined to be approximated by a PNG gAMA chunk value of
+0.45455 (1/2.2) for PNG.  The value implicitly includes any viewing
+correction required to take account of any differences in the color
+environment of the original scene and the intended display environment; the
+value expresses how to *decode* the image for display, not how the original
+data was *encoded*.
+
+sRGB provides a peg for the PNG standard by defining a viewing environment.
+sRGB itself, and earlier TV standards, actually use a more complex transform
+(a linear portion then a gamma 2.4 power law) than PNG can express.  (PNG is
+limited to simple power laws.)  By saying that an image for direct display on
+an sRGB conformant system should be stored with a gAMA chunk value of 45455
+(11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
+makes it possible to derive values for other display systems and
+environments.
+
+The Mac value is deduced from the sRGB based on an assumption that the actual
+extra viewing correction used in early Mac display systems was implemented as
+a power 1.45 lookup table.
+
+Any system where a programmable lookup table is used or where the behavior of
+the final display device characteristics can be changed requires system
+specific code to obtain the current characteristic.  However this can be
+difficult and most PNG gamma correction only requires an approximate value.
+
+By default, if png_set_alpha_mode() is not called, libpng assumes that all
+values are unencoded, linear, values and that the output device also has a
+linear characteristic.  This is only very rarely correct - it is invariably
+better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
+default if you don't know what the right answer is!
+
+The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
+10.6) which used a correction table to implement a somewhat lower gamma on an
+otherwise sRGB system.
+
+Both these values are reserved (not simple gamma values) in order to allow
+more precise correction internally in the future.
+
+NOTE: the values can be passed to either the fixed or floating
+point APIs, but the floating point API will also accept floating point
+values.
+
+The second thing you may need to tell libpng about is how your system handles
+alpha channel information.  Some, but not all, PNG files contain an alpha
+channel.  To display these files correctly you need to compose the data onto a
+suitable background, as described in the PNG specification.
+
+Libpng only supports composing onto a single color (using png_set_background;
+see below).  Otherwise you must do the composition yourself and, in this case,
+you may need to call png_set_alpha_mode:
+
+   #if PNG_LIBPNG_VER >= 10504
+      png_set_alpha_mode(png_ptr, mode, screen_gamma);
+   #else
+      png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma);
+   #endif
+
+The screen_gamma value is the same as the argument to png_set_gamma; however,
+how it affects the output depends on the mode.  png_set_alpha_mode() sets the
+file gamma default to 1/screen_gamma, so normally you don't need to call
+png_set_gamma.  If you need different defaults call png_set_gamma() before
+png_set_alpha_mode() - if you call it after it will override the settings made
+by png_set_alpha_mode().
+
+The mode is as follows:
+
+    PNG_ALPHA_PNG: The data is encoded according to the PNG
+specification.  Red, green and blue, or gray, components are
+gamma encoded color values and are not premultiplied by the
+alpha value.  The alpha value is a linear measure of the
+contribution of the pixel to the corresponding final output pixel.
+
+You should normally use this format if you intend to perform
+color correction on the color values; most, maybe all, color
+correction software has no handling for the alpha channel and,
+anyway, the math to handle pre-multiplied component values is
+unnecessarily complex.
+
+Before you do any arithmetic on the component values you need
+to remove the gamma encoding and multiply out the alpha
+channel.  See the PNG specification for more detail.  It is
+important to note that when an image with an alpha channel is
+scaled, linear encoded, pre-multiplied component values must
+be used!
+
+The remaining modes assume you don't need to do any further color correction or
+that if you do, your color correction software knows all about alpha (it
+probably doesn't!).  They 'associate' the alpha with the color information by
+storing color channel values that have been scaled by the alpha.  The
+advantage is that the color channels can be resampled (the image can be
+scaled) in this form.  The disadvantage is that normal practice is to store
+linear, not (gamma) encoded, values and this requires 16-bit channels for
+still images rather than the 8-bit channels that are just about sufficient if
+gamma encoding is used.  In addition all non-transparent pixel values,
+including completely opaque ones, must be gamma encoded to produce the final
+image.  These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+described below (the latter being the two common names for associated alpha
+color channels). Note that PNG files always contain non-associated color
+channels; png_set_alpha_mode() with one of the modes causes the decoder to
+convert the pixels to an associated form before returning them to your
+application.
+
+Since it is not necessary to perform arithmetic on opaque color values so
+long as they are not to be resampled and are in the final color space it is
+possible to optimize the handling of alpha by storing the opaque pixels in
+the PNG format (adjusted for the output color space) while storing partially
+opaque pixels in the standard, linear, format.  The accuracy required for
+standard alpha composition is relatively low, because the pixels are
+isolated, therefore typically the accuracy loss in storing 8-bit linear
+values is acceptable.  (This is not true if the alpha channel is used to
+simulate transparency over large areas - use 16 bits or the PNG mode in
+this case!)  This is the 'OPTIMIZED' mode.  For this mode a pixel is
+treated as opaque only if the alpha value is equal to the maximum value.
+
+    PNG_ALPHA_STANDARD:  The data libpng produces is encoded in the
+standard way assumed by most correctly written graphics software.
+The gamma encoding will be removed by libpng and the
+linear component values will be pre-multiplied by the
+alpha channel.
+
+With this format the final image must be re-encoded to
+match the display gamma before the image is displayed.
+If your system doesn't do that, yet still seems to
+perform arithmetic on the pixels without decoding them,
+it is broken - check out the modes below.
+
+With PNG_ALPHA_STANDARD libpng always produces linear
+component values, whatever screen_gamma you supply.  The
+screen_gamma value is, however, used as a default for
+the file gamma if the PNG file has no gamma information.
+
+If you call png_set_gamma() after png_set_alpha_mode() you
+will override the linear encoding.  Instead the
+pre-multiplied pixel values will be gamma encoded but
+the alpha channel will still be linear.  This may
+actually match the requirements of some broken software,
+but it is unlikely.
+
+While linear 8-bit data is often used it has
+insufficient precision for any image with a reasonable
+dynamic range.  To avoid problems, and if your software
+supports it, use png_set_expand_16() to force all
+components to 16 bits.
+
+    PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD
+except that completely opaque pixels are gamma encoded according to
+the screen_gamma value.  Pixels with alpha less than 1.0
+will still have linear components.
+
+Use this format if you have control over your
+compositing software and so don't do other arithmetic
+(such as scaling) on the data you get from libpng.  Your
+compositing software can simply copy opaque pixels to
+the output but still has linear values for the
+non-opaque pixels.
+
+In normal compositing, where the alpha channel encodes
+partial pixel coverage (as opposed to broad area
+translucency), the inaccuracies of the 8-bit
+representation of non-opaque pixels are irrelevant.
+
+You can also try this format if your software is broken;
+it might look better.
+
+    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD; however, all component
+values, including the alpha channel are gamma encoded.  This is
+broken because, in practice, no implementation that uses this choice
+correctly undoes the encoding before handling alpha composition.  Use this
+choice only if other serious errors in the software or hardware you use
+mandate it.  In most cases of broken software or hardware the bug in the
+final display manifests as a subtle halo around composited parts of the
+image.  You may not even perceive this as a halo; the composited part of
+the image may simply appear separate from the background, as though it had
+been cut out of paper and pasted on afterward.
+
+If you don't have to deal with bugs in software or hardware, or if you can fix
+them, there are three recommended ways of using png_set_alpha_mode():
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
+       screen_gamma);
+
+You can do color correction on the result (libpng does not currently
+support color correction internally).  When you handle the alpha channel
+you need to undo the gamma encoding and multiply out the alpha.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
+       screen_gamma);
+   png_set_expand_16(png_ptr);
+
+If you are using the high level interface, don't call png_set_expand_16();
+instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
+
+With this mode you can't do color correction, but you can do arithmetic,
+including composition and scaling, on the data without further processing.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
+       screen_gamma);
+
+You can avoid the expansion to 16-bit components with this mode, but you
+lose the ability to scale the image or perform other linear arithmetic.
+All you can do is compose the result onto a matching output.  Since this
+mode is libpng-specific you also need to write your own composition
+software.
+
+The following are examples of calls to png_set_alpha_mode to achieve the
+required overall gamma correction and, where necessary, alpha
+premultiplication.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+
+Choices for the alpha_mode are
+
+    PNG_ALPHA_PNG           0 /* according to the PNG standard */
+    PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
+    PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
+    PNG_ALPHA_PREMULTIPLIED 1 /* as above */
+    PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
+    PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
+
+PNG_ALPHA_PNG is the default libpng handling of the alpha channel. It is not
+pre-multiplied into the color components. In addition the call states
+that the output is for a sRGB system and causes all PNG files without gAMA
+chunks to be assumed to be encoded using sRGB.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+In this case the output is assumed to be something like an sRGB conformant
+display preceded by a power-law lookup table of power 1.45.  This is how
+early Mac systems behaved.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+
+This is the classic Jim Blinn approach and will work in academic
+environments where everything is done by the book.  It has the shortcoming
+of assuming that input PNG data with no gamma information is linear - this
+is unlikely to be correct unless the PNG files were generated locally.
+Most of the time the output precision will be so low as to show
+significant banding in dark areas of the image.
+
+    png_set_expand_16(pp);
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+
+This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
+are assumed to have the sRGB encoding if not marked with a gamma value and
+the output is always 16 bits per component.  This permits accurate scaling
+and processing of the data.  If you know that your input PNG files were
+generated locally you might need to replace PNG_DEFAULT_sRGB with the
+correct value for your system.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+
+If you just need to composite the PNG image onto an existing background
+and if you control the code that does this you can use the optimization
+setting.  In this case you just copy completely opaque pixels to the
+output.  For pixels that are not completely transparent (you just skip
+those) you do the composition math using png_composite or png_composite_16
+below then encode the resultant 8-bit or 16-bit values to match the output
+encoding.
+
+    Other cases
+
+If neither the PNG nor the standard linear encoding work for you because
+of the software or hardware you use then you have a big problem.  The PNG
+case will probably result in halos around the image.  The linear encoding
+will probably result in a washed out, too bright, image (it's actually too
+contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
+substantially reduce the halos.  Alternatively try:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+
+This option will also reduce the halos, but there will be slight dark
+halos round the opaque parts of the image where the background is light.
+In the OPTIMIZED mode the halos will be light halos where the background
+is dark.  Take your pick - the halos are unavoidable unless you can get
+your hardware/software fixed!  (The OPTIMIZED approach is slightly
+faster.)
+
+When the default gamma of PNG files doesn't match the output gamma.
+If you have PNG files with no gamma information png_set_alpha_mode allows
+you to provide a default gamma, but it also sets the output gamma to the
+matching value.  If you know your PNG files have a gamma that doesn't
+match the output you can take advantage of the fact that
+png_set_alpha_mode always sets the output gamma but only sets the PNG
+default if it is not already set:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+The first call sets both the default and the output gamma values, the
+second call overrides the output gamma without changing the default.  This
+is easier than achieving the same effect with png_set_gamma.  You must use
+PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+fire if more than one call to png_set_alpha_mode and png_set_background is
+made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+are ignored.
+
+If you don't need, or can't handle, the alpha channel you can call
+png_set_background() to remove it by compositing against a fixed color.  Don't
+call png_set_strip_alpha() to do this - it will leave spurious pixel values in
+transparent parts of this image.
+
+   png_set_background(png_ptr, &background_color,
+       PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
+
+The background_color is an RGB or grayscale value according to the data format
+libpng will produce for you.  Because you don't yet know the format of the PNG
+file, if you call png_set_background at this point you must arrange for the
+format produced by libpng to always have 8-bit or 16-bit components and then
+store the color as an 8-bit or 16-bit color as appropriate.  The color contains
+separate gray and RGB component values, so you can let libpng produce gray or
+RGB output according to the input format, but low bit depth grayscale images
+must always be converted to at least 8-bit format.  (Even though low bit depth
+grayscale images can't have an alpha channel they can have a transparent
+color!)
+
+You set the transforms you need later, either as flags to the high level
+interface or libpng API calls for the low level interface.  For reference the
+settings and API calls required are:
+
+8-bit values:
+   PNG_TRANSFORM_SCALE_16 | PNG_EXPAND
+   png_set_expand(png_ptr); png_set_scale_16(png_ptr);
+
+   If you must get exactly the same inaccurate results
+   produced by default in versions prior to libpng-1.5.4,
+   use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr)
+   instead.
+
+16-bit values:
+   PNG_TRANSFORM_EXPAND_16
+   png_set_expand_16(png_ptr);
+
+In either case palette image data will be expanded to RGB.  If you just want
+color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
+to the list.
+
+Calling png_set_background before the PNG file header is read will not work
+prior to libpng-1.5.4.  Because the failure may result in unexpected warnings or
+errors it is therefore much safer to call png_set_background after the head has
+been read.  Unfortunately this means that prior to libpng-1.5.4 it cannot be
+used with the high level interface.
+
+The high-level read interface
+
+At this point there are two ways to proceed; through the high-level
+read interface, or through a sequence of low-level read operations.
+You can use the high-level interface if (a) you are willing to read
+the entire image into memory, and (b) the input transformations
+you want to do are limited to the following set:
+
+    PNG_TRANSFORM_IDENTITY      No transformation
+    PNG_TRANSFORM_SCALE_16      Strip 16-bit samples to
+                                8-bit accurately
+    PNG_TRANSFORM_STRIP_16      Chop 16-bit samples to
+                                8-bit less accurately
+    PNG_TRANSFORM_STRIP_ALPHA   Discard the alpha channel
+    PNG_TRANSFORM_PACKING       Expand 1, 2 and 4-bit
+                                samples to bytes
+    PNG_TRANSFORM_PACKSWAP      Change order of packed
+                                pixels to LSB first
+    PNG_TRANSFORM_EXPAND        Perform set_expand()
+    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
+    PNG_TRANSFORM_SHIFT         Normalize pixels to the
+                                sBIT depth
+    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
+                                to BGRA
+    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
+                                to AG
+    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
+                                to transparency
+    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
+    PNG_TRANSFORM_GRAY_TO_RGB   Expand grayscale samples
+                                to RGB (or GA to RGBA)
+    PNG_TRANSFORM_EXPAND_16     Expand samples to 16 bits
+
+(This excludes setting a background color, doing gamma transformation,
+quantizing, and setting filler.)  If this is the case, simply do this:
+
+    png_read_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some
+set of transformation flags.  This call is equivalent to png_read_info(),
+followed the set of transformations indicated by the transform mask,
+then png_read_image(), and finally png_read_end().
+
+(The final parameter of this call is not yet used.  Someday it might point
+to transformation parameters required by some future input transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_read_png().
+
+After you have called png_read_png(), you can retrieve the image data
+with
+
+   row_pointers = png_get_rows(png_ptr, info_ptr);
+
+where row_pointers is an array of pointers to the pixel data for each row:
+
+   png_bytep row_pointers[height];
+
+If you know your image size and pixel size ahead of time, you can allocate
+row_pointers prior to calling png_read_png() with
+
+   if (height > PNG_UINT_32_MAX / (sizeof (png_bytep)))
+      png_error(png_ptr,
+          "Image is too tall to process in memory");
+
+   if (width > PNG_UINT_32_MAX / pixel_size)
+      png_error(png_ptr,
+          "Image is too wide to process in memory");
+
+   row_pointers = png_malloc(png_ptr,
+       height*(sizeof (png_bytep)));
+
+   for (int i = 0; i < height, i++)
+      row_pointers[i] = NULL;  /* security precaution */
+
+   for (int i = 0; i < height, i++)
+      row_pointers[i] = png_malloc(png_ptr,
+          width*pixel_size);
+
+   png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+Alternatively you could allocate your image in one big block and define
+row_pointers[i] to point into the proper places in your block, but first
+be sure that your platform is able to allocate such a large buffer:
+
+   /* Guard against integer overflow */
+   if (height > PNG_SIZE_MAX/(width*pixel_size))
+      png_error(png_ptr, "image_data buffer would be too large");
+
+   png_bytep buffer = png_malloc(png_ptr,
+      height*width*pixel_size);
+
+   for (int i = 0; i < height, i++)
+      row_pointers[i] = buffer + i*width*pixel_size;
+
+   png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+If you use png_set_rows(), the application is responsible for freeing
+row_pointers (and row_pointers[i], if they were separately allocated).
+
+If you don't allocate row_pointers ahead of time, png_read_png() will
+do it, and it'll be free'ed by libpng when you call png_destroy_*().
+
+The low-level read interface
+
+If you are going the low-level route, you are now ready to read all
+the file information up to the actual image data.  You do this with a
+call to png_read_info().
+
+    png_read_info(png_ptr, info_ptr);
+
+This will process all chunks up to but not including the image data.
+
+This also copies some of the data from the PNG file into the decode structure
+for use in later transformations.  Important information copied in is:
+
+1) The PNG file gamma from the gAMA chunk.  This overwrites the default value
+provided by an earlier call to png_set_gamma or png_set_alpha_mode.
+
+2) Prior to libpng-1.5.4 the background color from a bKGd chunk.  This
+damages the information provided by an earlier call to png_set_background
+resulting in unexpected behavior.  Libpng-1.5.4 no longer does this.
+
+3) The number of significant bits in each component value.  Libpng uses this to
+optimize gamma handling by reducing the internal lookup table sizes.
+
+4) The transparent color information from a tRNS chunk.  This can be modified by
+a later call to png_set_tRNS.
+
+Querying the info structure
+
+Functions are used to get the information from the info_ptr once it
+has been read.  Note that these fields may not be completely filled
+in until png_read_end() has read the chunk data following the image.
+
+    png_get_IHDR(png_ptr, info_ptr, &width, &height,
+       &bit_depth, &color_type, &interlace_type,
+       &compression_type, &filter_method);
+
+    width          - holds the width of the image
+                     in pixels (up to 2^31).
+
+    height         - holds the height of the image
+                     in pixels (up to 2^31).
+
+    bit_depth      - holds the bit depth of one of the
+                     image channels.  (valid values are
+                     1, 2, 4, 8, 16 and depend also on
+                     the color_type.  See also
+                     significant bits (sBIT) below).
+
+    color_type     - describes which color/alpha channels
+                         are present.
+                     PNG_COLOR_TYPE_GRAY
+                        (bit depths 1, 2, 4, 8, 16)
+                     PNG_COLOR_TYPE_GRAY_ALPHA
+                        (bit depths 8, 16)
+                     PNG_COLOR_TYPE_PALETTE
+                        (bit depths 1, 2, 4, 8)
+                     PNG_COLOR_TYPE_RGB
+                        (bit_depths 8, 16)
+                     PNG_COLOR_TYPE_RGB_ALPHA
+                        (bit_depths 8, 16)
+
+                     PNG_COLOR_MASK_PALETTE
+                     PNG_COLOR_MASK_COLOR
+                     PNG_COLOR_MASK_ALPHA
+
+    interlace_type - (PNG_INTERLACE_NONE or
+                     PNG_INTERLACE_ADAM7)
+
+    compression_type - (must be PNG_COMPRESSION_TYPE_BASE
+                     for PNG 1.0)
+
+    filter_method  - (must be PNG_FILTER_TYPE_BASE
+                     for PNG 1.0, and can also be
+                     PNG_INTRAPIXEL_DIFFERENCING if
+                     the PNG datastream is embedded in
+                     a MNG-1.0 datastream)
+
+    Any of width, height, color_type, bit_depth,
+    interlace_type, compression_type, or filter_method can
+    be NULL if you are not interested in their values.
+
+    Note that png_get_IHDR() returns 32-bit data into
+    the application's width and height variables.
+    This is an unsafe situation if these are not png_uint_32
+    variables.  In such situations, the
+    png_get_image_width() and png_get_image_height()
+    functions described below are safer.
+
+    width            = png_get_image_width(png_ptr,
+                         info_ptr);
+
+    height           = png_get_image_height(png_ptr,
+                         info_ptr);
+
+    bit_depth        = png_get_bit_depth(png_ptr,
+                         info_ptr);
+
+    color_type       = png_get_color_type(png_ptr,
+                         info_ptr);
+
+    interlace_type   = png_get_interlace_type(png_ptr,
+                         info_ptr);
+
+    compression_type = png_get_compression_type(png_ptr,
+                         info_ptr);
+
+    filter_method    = png_get_filter_type(png_ptr,
+                         info_ptr);
+
+    channels = png_get_channels(png_ptr, info_ptr);
+
+    channels       - number of channels of info for the
+                     color type (valid values are 1 (GRAY,
+                     PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
+                     4 (RGB_ALPHA or RGB + filler byte))
+
+    rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+    rowbytes       - number of bytes needed to hold a row
+                     This value, the bit_depth, color_type,
+                     and the number of channels can change
+                     if you use transforms such as
+                     png_set_expand(). See
+                     png_read_update_info(), below.
+
+    signature = png_get_signature(png_ptr, info_ptr);
+
+    signature      - holds the signature read from the
+                     file (if any).  The data is kept in
+                     the same offset it would be if the
+                     whole signature were read (i.e. if an
+                     application had already read in 4
+                     bytes of signature before starting
+                     libpng, the remaining 4 bytes would
+                     be in signature[4] through signature[7]
+                     (see png_set_sig_bytes())).
+
+These are also important, but their validity depends on whether the chunk
+has been read.  The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
+png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
+data has been read, or zero if it is missing.  The parameters to the
+png_get_<chunk> are set directly if they are simple data types, or a
+pointer into the info_ptr is returned for any complex types.
+
+The colorspace data from gAMA, cHRM, sRGB, iCCP, and sBIT chunks
+is simply returned to give the application information about how the
+image was encoded.  Libpng itself only does transformations using the file
+gamma when combining semitransparent pixels with the background color, and,
+since libpng-1.6.0, when converting between 8-bit sRGB and 16-bit linear pixels
+within the simplified API.  Libpng also uses the file gamma when converting
+RGB to gray, beginning with libpng-1.0.5, if the application calls
+png_set_rgb_to_gray()).
+
+    png_get_PLTE(png_ptr, info_ptr, &palette,
+                     &num_palette);
+
+    palette        - the palette for the file
+                     (array of png_color)
+
+    num_palette    - number of entries in the palette
+
+    png_get_gAMA(png_ptr, info_ptr, &file_gamma);
+    png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
+
+    file_gamma     - the gamma at which the file is
+                     written (PNG_INFO_gAMA)
+
+    int_file_gamma - 100,000 times the gamma at which the
+                     file is written
+
+    png_get_cHRM(png_ptr, info_ptr,  &white_x, &white_y, &red_x,
+                     &red_y, &green_x, &green_y, &blue_x, &blue_y)
+    png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z,
+                     &green_X, &green_Y, &green_Z, &blue_X, &blue_Y,
+                     &blue_Z)
+    png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x,
+                     &int_white_y, &int_red_x, &int_red_y,
+                     &int_green_x, &int_green_y, &int_blue_x,
+                     &int_blue_y)
+    png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y,
+                     &int_red_Z, &int_green_X, &int_green_Y,
+                     &int_green_Z, &int_blue_X, &int_blue_Y,
+                     &int_blue_Z)
+
+    {white,red,green,blue}_{x,y}
+                     A color space encoding specified using the
+                     chromaticities of the end points and the
+                     white point. (PNG_INFO_cHRM)
+
+    {red,green,blue}_{X,Y,Z}
+                     A color space encoding specified using the
+                     encoding end points - the CIE tristimulus
+                     specification of the intended color of the red,
+                     green and blue channels in the PNG RGB data.
+                     The white point is simply the sum of the three
+                     end points. (PNG_INFO_cHRM)
+
+    png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
+
+    srgb_intent -    the rendering intent (PNG_INFO_sRGB)
+                     The presence of the sRGB chunk
+                     means that the pixel data is in the
+                     sRGB color space.  This chunk also
+                     implies specific values of gAMA and
+                     cHRM.
+
+    png_get_iCCP(png_ptr, info_ptr, &name,
+       &compression_type, &profile, &proflen);
+
+    name             - The profile name.
+
+    compression_type - The compression type; always
+                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+                       You may give NULL to this argument to
+                       ignore it.
+
+    profile          - International Color Consortium color
+                       profile data. May contain NULs.
+
+    proflen          - length of profile data in bytes.
+
+    png_get_sBIT(png_ptr, info_ptr, &sig_bit);
+
+    sig_bit        - the number of significant bits for
+                     (PNG_INFO_sBIT) each of the gray,
+                     red, green, and blue channels,
+                     whichever are appropriate for the
+                     given color type (png_color_16)
+
+    png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
+                     &num_trans, &trans_color);
+
+    trans_alpha    - array of alpha (transparency)
+                     entries for palette (PNG_INFO_tRNS)
+
+    num_trans      - number of transparent entries
+                     (PNG_INFO_tRNS)
+
+    trans_color    - graylevel or color sample values of
+                     the single transparent color for
+                     non-paletted images (PNG_INFO_tRNS)
+
+    png_get_eXIf_1(png_ptr, info_ptr, &num_exif, &exif);
+
+    exif           - Exif profile (array of png_byte)
+                     (PNG_INFO_eXIf)
+
+    png_get_hIST(png_ptr, info_ptr, &hist);
+
+    hist           - histogram of palette (array of
+                     png_uint_16) (PNG_INFO_hIST)
+
+    png_get_tIME(png_ptr, info_ptr, &mod_time);
+
+    mod_time       - time image was last modified
+                     (PNG_INFO_tIME)
+
+    png_get_bKGD(png_ptr, info_ptr, &background);
+
+    background     - background color (of type
+                     png_color_16p) (PNG_INFO_bKGD)
+                     valid 16-bit red, green and blue
+                     values, regardless of color_type
+
+    num_comments   = png_get_text(png_ptr, info_ptr,
+                     &text_ptr, &num_text);
+
+    num_comments   - number of comments
+
+    text_ptr       - array of png_text holding image
+                     comments
+
+    text_ptr[i].compression - type of compression used
+                 on "text" PNG_TEXT_COMPRESSION_NONE
+                           PNG_TEXT_COMPRESSION_zTXt
+                           PNG_ITXT_COMPRESSION_NONE
+                           PNG_ITXT_COMPRESSION_zTXt
+
+    text_ptr[i].key   - keyword for comment.  Must contain
+                         1-79 characters.
+
+    text_ptr[i].text  - text comments for current
+                         keyword.  Can be empty.
+
+    text_ptr[i].text_length - length of text string,
+                 after decompression, 0 for iTXt
+
+    text_ptr[i].itxt_length - length of itxt string,
+                 after decompression, 0 for tEXt/zTXt
+
+    text_ptr[i].lang  - language of comment (empty
+                         string for unknown).
+
+    text_ptr[i].lang_key  - keyword in UTF-8
+                         (empty string for unknown).
+
+    Note that the itxt_length, lang, and lang_key
+    members of the text_ptr structure only exist when the
+    library is built with iTXt chunk support.  Prior to
+    libpng-1.4.0 the library was built by default without
+    iTXt support. Also note that when iTXt is supported,
+    they contain NULL pointers when the "compression"
+    field contains PNG_TEXT_COMPRESSION_NONE or
+    PNG_TEXT_COMPRESSION_zTXt.
+
+    num_text       - number of comments (same as
+                     num_comments; you can put NULL here
+                     to avoid the duplication)
+
+    Note while png_set_text() will accept text, language,
+    and translated keywords that can be NULL pointers, the
+    structure returned by png_get_text will always contain
+    regular zero-terminated C strings.  They might be
+    empty strings but they will never be NULL pointers.
+
+    num_spalettes = png_get_sPLT(png_ptr, info_ptr,
+       &palette_ptr);
+
+    num_spalettes  - number of sPLT chunks read.
+
+    palette_ptr    - array of palette structures holding
+                     contents of one or more sPLT chunks
+                     read.
+
+    png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
+       &unit_type);
+
+    offset_x       - positive offset from the left edge
+                     of the screen (can be negative)
+
+    offset_y       - positive offset from the top edge
+                     of the screen (can be negative)
+
+    unit_type      - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+    png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
+       &unit_type);
+
+    res_x          - pixels/unit physical resolution in
+                     x direction
+
+    res_y          - pixels/unit physical resolution in
+                     x direction
+
+    unit_type      - PNG_RESOLUTION_UNKNOWN,
+                     PNG_RESOLUTION_METER
+
+    png_get_sCAL(png_ptr, info_ptr, &unit, &width,
+       &height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+
+    height      - height of a pixel in physical scale units
+                 (width and height are doubles)
+
+    png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
+       &height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+                  (expressed as a string)
+
+    height      - height of a pixel in physical scale units
+                 (width and height are strings like "2.54")
+
+    num_unknown_chunks = png_get_unknown_chunks(png_ptr,
+       info_ptr, &unknowns)
+
+    unknowns          - array of png_unknown_chunk
+                        structures holding unknown chunks
+
+    unknowns[i].name  - name of unknown chunk
+
+    unknowns[i].data  - data of unknown chunk
+
+    unknowns[i].size  - size of unknown chunk's data
+
+    unknowns[i].location - position of chunk in file
+
+    The value of "i" corresponds to the order in which the
+    chunks were read from the PNG file or inserted with the
+    png_set_unknown_chunks() function.
+
+    The value of "location" is a bitwise "or" of
+
+         PNG_HAVE_IHDR  (0x01)
+         PNG_HAVE_PLTE  (0x02)
+         PNG_AFTER_IDAT (0x08)
+
+The data from the pHYs chunk can be retrieved in several convenient
+forms:
+
+    res_x = png_get_x_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_y = png_get_y_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_x_and_y = png_get_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_x = png_get_x_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    res_y = png_get_y_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    res_x_and_y = png_get_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
+       info_ptr)
+
+    Each of these returns 0 [signifying "unknown"] if
+       the data is not present or if res_x is 0;
+       res_x_and_y is 0 if res_x != res_y
+
+    Note that because of the way the resolutions are
+       stored internally, the inch conversions won't
+       come out to exactly even number.  For example,
+       72 dpi is stored as 0.28346 pixels/meter, and
+       when this is retrieved it is 71.9988 dpi, so
+       be sure to round the returned value appropriately
+       if you want to display a reasonable-looking result.
+
+The data from the oFFs chunk can be retrieved in several convenient
+forms:
+
+    x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
+
+    y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
+
+    x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
+
+    y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
+
+    Each of these returns 0 [signifying "unknown" if both
+       x and y are 0] if the data is not present or if the
+       chunk is present but the unit is the pixel.  The
+       remark about inexact inch conversions applies here
+       as well, because a value in inches can't always be
+       converted to microns and back without some loss
+       of precision.
+
+For more information, see the
+PNG specification for chunk contents.  Be careful with trusting
+rowbytes, as some of the transformations could increase the space
+needed to hold a row (expand, filler, gray_to_rgb, etc.).
+See png_read_update_info(), below.
+
+A quick word about text_ptr and num_text.  PNG stores comments in
+keyword/text pairs, one pair per chunk, with no limit on the number
+of text chunks, and a 2^31 byte limit on their size.  While there are
+suggested keywords, there is no requirement to restrict the use to these
+strings.  It is strongly suggested that keywords and text be sensible
+to humans (that's the point), so don't use abbreviations.  Non-printing
+symbols are not allowed.  See the PNG specification for more details.
+There is also no requirement to have text after the keyword.
+
+Keywords should be limited to 79 Latin-1 characters without leading or
+trailing spaces, but non-consecutive spaces are allowed within the
+keyword.  It is possible to have the same keyword any number of times.
+The text_ptr is an array of png_text structures, each holding a
+pointer to a language string, a pointer to a keyword and a pointer to
+a text string.  The text string, language code, and translated
+keyword may be empty or NULL pointers.  The keyword/text
+pairs are put into the array in the order that they are received.
+However, some or all of the text chunks may be after the image, so, to
+make sure you have read all the text chunks, don't mess with these
+until after you read the stuff after the image.  This will be
+mentioned again below in the discussion that goes with png_read_end().
+
+Input transformations
+
+After you've read the header information, you can set up the library
+to handle any special transformations of the image data.  The various
+ways to transform the data will be described in the order that they
+should occur.  This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths.
+
+Transformations you request are ignored if they don't have any meaning for a
+particular input data format.  However some transformations can have an effect
+as a result of a previous transformation.  If you specify a contradictory set of
+transformations, for example both adding and removing the alpha channel, you
+cannot predict the final result.
+
+The color used for the transparency values should be supplied in the same
+format/depth as the current image data.  It is stored in the same format/depth
+as the image data in a tRNS chunk, so this is what libpng expects for this data.
+
+The color used for the background value depends on the need_expand argument as
+described below.
+
+Data will be decoded into the supplied row buffers packed into bytes
+unless the library has been told to transform it into another format.
+For example, 4 bit/pixel paletted or grayscale data will be returned
+2 pixels/byte with the leftmost pixel in the high-order bits of the byte,
+unless png_set_packing() is called.  8-bit RGB data will be stored
+in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
+is called to insert filler bytes, either before or after each RGB triplet.
+
+16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
+byte of the color value first, unless png_set_scale_16() is called to
+transform it to regular RGB RGB triplets, or png_set_filler() or
+png_set_add alpha() is called to insert two filler bytes, either before
+or after each RRGGBB triplet.  Similarly, 8-bit or 16-bit grayscale data can
+be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(),
+or png_set_scale_16().
+
+The following code transforms grayscale images of less than 8 to 8 bits,
+changes paletted images to RGB, and adds a full alpha channel if there is
+transparency information in a tRNS chunk.  This is most useful on
+grayscale images with bit depths of 2 or 4 or if there is a multiple-image
+viewing application that wishes to treat all images in the same way.
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+       png_set_palette_to_rgb(png_ptr);
+
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+       png_set_tRNS_to_alpha(png_ptr);
+
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+       png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+The first two functions are actually aliases for png_set_expand(), added
+in libpng version 1.0.4, with the function names expanded to improve code
+readability.  In some future version they may actually do different
+things.
+
+As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
+added.  It expands the sample depth without changing tRNS to alpha.
+
+As of libpng version 1.5.2, png_set_expand_16() was added.  It behaves as
+png_set_expand(); however, the resultant channels have 16 bits rather than 8.
+Use this when the output color or gray channels are made linear to avoid fairly
+severe accuracy loss.
+
+    if (bit_depth < 16)
+       png_set_expand_16(png_ptr);
+
+PNG can have files with 16 bits per channel.  If you only can handle
+8 bits per channel, this will strip the pixels down to 8-bit.
+
+    if (bit_depth == 16)
+    {
+#if PNG_LIBPNG_VER >= 10504
+       png_set_scale_16(png_ptr);
+#else
+       png_set_strip_16(png_ptr);
+#endif
+    }
+
+(The more accurate "png_set_scale_16()" API became available in libpng version
+1.5.4).
+
+If you need to process the alpha channel on the image separately from the image
+data (for example if you convert it to a bitmap mask) it is possible to have
+libpng strip the channel leaving just RGB or gray data:
+
+    if (color_type & PNG_COLOR_MASK_ALPHA)
+       png_set_strip_alpha(png_ptr);
+
+If you strip the alpha channel you need to find some other way of dealing with
+the information.  If, instead, you want to convert the image to an opaque
+version with no alpha channel use png_set_background; see below.
+
+As of libpng version 1.5.2, almost all useful expansions are supported, the
+major omissions are conversion of grayscale to indexed images (which can be
+done trivially in the application) and conversion of indexed to grayscale (which
+can be done by a trivial manipulation of the palette.)
+
+In the following table, the 01 means grayscale with depth<8, 31 means
+indexed with depth<8, other numerals represent the color type, "T" means
+the tRNS chunk is present, A means an alpha channel is present, and O
+means tRNS or alpha is present but all pixels in the image are opaque.
+
+  FROM  01  31   0  0T  0O   2  2T  2O   3  3T  3O  4A  4O  6A  6O
+   TO
+   01    -  [G]  -   -   -   -   -   -   -   -   -   -   -   -   -
+   31   [Q]  Q  [Q] [Q] [Q]  Q   Q   Q   Q   Q   Q  [Q] [Q]  Q   Q
+    0    1   G   +   .   .   G   G   G   G   G   G   B   B  GB  GB
+   0T    lt  Gt  t   +   .   Gt  G   G   Gt  G   G   Bt  Bt GBt GBt
+   0O    lt  Gt  t   .   +   Gt  Gt  G   Gt  Gt  G   Bt  Bt GBt GBt
+    2    C   P   C   C   C   +   .   .   C   -   -  CB  CB   B   B
+   2T    Ct  -   Ct  C   C   t   +   t   -   -   -  CBt CBt  Bt  Bt
+   2O    Ct  -   Ct  C   C   t   t   +   -   -   -  CBt CBt  Bt  Bt
+    3   [Q]  p  [Q] [Q] [Q]  Q   Q   Q   +   .   .  [Q] [Q]  Q   Q
+   3T   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   +   t  [Qt][Qt] Qt  Qt
+   3O   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   t   +  [Qt][Qt] Qt  Qt
+   4A    lA  G   A   T   T   GA  GT  GT  GA  GT  GT  +   BA  G  GBA
+   4O    lA GBA  A   T   T   GA  GT  GT  GA  GT  GT  BA  +  GBA  G
+   6A    CA  PA  CA  C   C   A   T  tT   PA  P   P   C  CBA  +   BA
+   6O    CA PBA  CA  C   C   A  tT   T   PA  P   P  CBA  C   BA  +
+
+Within the matrix,
+     "+" identifies entries where 'from' and 'to' are the same.
+     "-" means the transformation is not supported.
+     "." means nothing is necessary (a tRNS chunk can just be ignored).
+     "t" means the transformation is obtained by png_set_tRNS.
+     "A" means the transformation is obtained by png_set_add_alpha().
+     "X" means the transformation is obtained by png_set_expand().
+     "1" means the transformation is obtained by
+         png_set_expand_gray_1_2_4_to_8() (and by png_set_expand()
+         if there is no transparency in the original or the final
+         format).
+     "C" means the transformation is obtained by png_set_gray_to_rgb().
+     "G" means the transformation is obtained by png_set_rgb_to_gray().
+     "P" means the transformation is obtained by
+         png_set_expand_palette_to_rgb().
+     "p" means the transformation is obtained by png_set_packing().
+     "Q" means the transformation is obtained by png_set_quantize().
+     "T" means the transformation is obtained by
+         png_set_tRNS_to_alpha().
+     "B" means the transformation is obtained by
+         png_set_background(), or png_strip_alpha().
+
+When an entry has multiple transforms listed all are required to cause the
+right overall transformation.  When two transforms are separated by a comma
+either will do the job.  When transforms are enclosed in [] the transform should
+do the job but this is currently unimplemented - a different format will result
+if the suggested transformations are used.
+
+In PNG files, the alpha channel in an image
+is the level of opacity.  If you need the alpha channel in an image to
+be the level of transparency instead of opacity, you can invert the
+alpha channel (or the tRNS chunk data) after it's read, so that 0 is
+fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
+images) is fully transparent, with
+
+    png_set_invert_alpha(png_ptr);
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit
+files.  This code expands to 1 pixel per byte without changing the
+values of the pixels:
+
+    if (bit_depth < 8)
+       png_set_packing(png_ptr);
+
+PNG files have possible bit depths of 1, 2, 4, 8, and 16.  All pixels
+stored in a PNG image have been "scaled" or "shifted" up to the next
+higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
+to 8 bits/sample in the range [0, 255]).  However, it is also possible
+to convert the PNG pixel data back to the original bit depth of the
+image.  This call reduces the pixels back down to the original bit depth:
+
+    png_color_8p sig_bit;
+
+    if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
+       png_set_shift(png_ptr, sig_bit);
+
+PNG files store 3-color pixels in red, green, blue order.  This code
+changes the storage of the pixels to blue, green, red:
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_bgr(png_ptr);
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
+into 4 or 8 bytes for windowing systems that need them in this format:
+
+    if (color_type == PNG_COLOR_TYPE_RGB)
+       png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
+
+where "filler" is the 8-bit or 16-bit number to fill with, and the location
+is either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
+you want the filler before the RGB or after. When filling an 8-bit pixel,
+the least significant 8 bits of the number are used, if a 16-bit number is
+supplied.  This transformation does not affect images that already have full
+alpha channels.  To add an opaque alpha channel, use filler=0xffff and
+PNG_FILLER_AFTER which will generate RGBA pixels.
+
+Note that png_set_filler() does not change the color type.  If you want
+to do that, you can add a true alpha channel with
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_GRAY)
+       png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
+
+where "filler" contains the alpha value to assign to each pixel.
+The png_set_add_alpha() function was added in libpng-1.2.7.
+
+If you are reading an image with an alpha channel, and you need the
+data as ARGB instead of the normal PNG format RGBA:
+
+    if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_swap_alpha(png_ptr);
+
+For some uses, you may want a grayscale image to be represented as
+RGB.  This code will do that conversion:
+
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+       png_set_gray_to_rgb(png_ptr);
+
+Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
+with alpha.
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_rgb_to_gray(png_ptr, error_action,
+          (double)red_weight, (double)green_weight);
+
+    error_action = 1: silently do the conversion
+
+    error_action = 2: issue a warning if the original
+                      image has any pixel where
+                      red != green or red != blue
+
+    error_action = 3: issue an error and abort the
+                      conversion if the original
+                      image has any pixel where
+                      red != green or red != blue
+
+    red_weight:       weight of red component
+
+    green_weight:     weight of green component
+                      If either weight is negative, default
+                      weights are used.
+
+In the corresponding fixed point API the red_weight and green_weight values are
+simply scaled by 100,000:
+
+    png_set_rgb_to_gray(png_ptr, error_action,
+       (png_fixed_point)red_weight,
+       (png_fixed_point)green_weight);
+
+If you have set error_action = 1 or 2, you can
+later check whether the image really was gray, after processing
+the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
+It will return a png_byte that is zero if the image was gray or
+1 if there were any non-gray pixels.  Background and sBIT data
+will be silently converted to grayscale, using the green channel
+data for sBIT, regardless of the error_action setting.
+
+The default values come from the PNG file cHRM chunk if present; otherwise, the
+defaults correspond to the ITU-R recommendation 709, and also the sRGB color
+space, as recommended in the Charles Poynton's Colour FAQ,
+Copyright (c) 2006-11-28 Charles Poynton, in section 9:
+
+<http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
+
+    Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
+
+Previous versions of this document, 1998 through 2002, recommended a slightly
+different formula:
+
+    Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+
+Libpng uses an integer approximation:
+
+    Y = (6968 * R + 23434 * G + 2366 * B)/32768
+
+The calculation is done in a linear colorspace, if the image gamma
+can be determined.
+
+The png_set_background() function has been described already; it tells libpng to
+composite images with alpha or simple transparency against the supplied
+background color.  For compatibility with versions of libpng earlier than
+libpng-1.5.4 it is recommended that you call the function after reading the file
+header, even if you don't want to use the color in a bKGD chunk, if one exists.
+
+If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
+you may use this color, or supply another color more suitable for
+the current display (e.g., the background color from a web page).  You
+need to tell libpng how the color is represented, both the format of the
+component values in the color (the number of bits) and the gamma encoding of the
+color.  The function takes two arguments, background_gamma_mode and need_expand
+to convey this information; however, only two combinations are likely to be
+useful:
+
+    png_color_16 my_background;
+    png_color_16p image_background;
+
+    if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+       png_set_background(png_ptr, image_background,
+           PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
+    else
+       png_set_background(png_ptr, &my_background,
+           PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
+
+The second call was described above - my_background is in the format of the
+final, display, output produced by libpng.  Because you now know the format of
+the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
+output and to retain palette images (the palette colors will be modified
+appropriately and the tRNS chunk removed.)  However, if you are doing this,
+take great care not to ask for transformations without checking first that
+they apply!
+
+In the first call the background color has the original bit depth and color type
+of the PNG file.  So, for palette images the color is supplied as a palette
+index and for low bit greyscale images the color is a reduced bit value in
+image_background->gray.
+
+If you didn't call png_set_gamma() before reading the file header, for example
+if you need your code to remain compatible with older versions of libpng prior
+to libpng-1.5.4, this is the place to call it.
+
+Do not call it if you called png_set_alpha_mode(); doing so will damage the
+settings put in place by png_set_alpha_mode().  (If png_set_alpha_mode() is
+supported then you can certainly do png_set_gamma() before reading the PNG
+header.)
+
+This API unconditionally sets the screen and file gamma values, so it will
+override the value in the PNG file unless it is called before the PNG file
+reading starts.  For this reason you must always call it with the PNG file
+value when you call it in this position:
+
+   if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
+      png_set_gamma(png_ptr, screen_gamma, file_gamma);
+
+   else
+      png_set_gamma(png_ptr, screen_gamma, 0.45455);
+
+If you need to reduce an RGB file to a paletted file, or if a paletted
+file has more entries than will fit on your screen, png_set_quantize()
+will do that.  Note that this is a simple match quantization that merely
+finds the closest color available.  This should work fairly well with
+optimized palettes, but fairly badly with linear color cubes.  If you
+pass a palette that is larger than maximum_colors, the file will
+reduce the number of colors in the palette so it will fit into
+maximum_colors.  If there is a histogram, libpng will use it to make
+more intelligent choices when reducing the palette.  If there is no
+histogram, it may not do as good a job.
+
+   if (color_type & PNG_COLOR_MASK_COLOR)
+   {
+      if (png_get_valid(png_ptr, info_ptr,
+          PNG_INFO_PLTE))
+      {
+         png_uint_16p histogram = NULL;
+
+         png_get_hIST(png_ptr, info_ptr,
+             &histogram);
+         png_set_quantize(png_ptr, palette, num_palette,
+            max_screen_colors, histogram, 1);
+      }
+
+      else
+      {
+         png_color std_color_cube[MAX_SCREEN_COLORS] =
+            { ... colors ... };
+
+         png_set_quantize(png_ptr, std_color_cube,
+            MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
+            NULL,0);
+      }
+   }
+
+PNG files describe monochrome as black being zero and white being one.
+The following code will reverse this (make black be one and white be
+zero):
+
+   if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
+      png_set_invert_mono(png_ptr);
+
+This function can also be used to invert grayscale and gray-alpha images:
+
+   if (color_type == PNG_COLOR_TYPE_GRAY ||
+       color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      png_set_invert_mono(png_ptr);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first).  This code changes the storage to the
+other way (little-endian, i.e. least significant bits first, the
+way PCs store them):
+
+    if (bit_depth == 16)
+       png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+    if (bit_depth < 8)
+       png_set_packswap(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs.  This is done by setting a callback
+with
+
+    png_set_read_user_transform_fn(png_ptr,
+        read_transform_fn);
+
+You must supply the function
+
+    void read_transform_fn(png_structp png_ptr, png_row_infop
+        row_info, png_bytep data)
+
+See pngtest.c for a working example.  Your function will be called
+after all of the other transformations have been processed.  Take care with
+interlaced images if you do the interlace yourself - the width of the row is the
+width in 'row_info', not the overall image width.
+
+If supported, libpng provides two information routines that you can use to find
+where you are in processing the image:
+
+   png_get_current_pass_number(png_structp png_ptr);
+   png_get_current_row_number(png_structp png_ptr);
+
+Don't try using these outside a transform callback - firstly they are only
+supported if user transforms are supported, secondly they may well return
+unexpected results unless the row is actually being processed at the moment they
+are called.
+
+With interlaced
+images the value returned is the row in the input sub-image image.  Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function, and you can inform libpng that your transform
+function will change the number of channels or bit depth with the
+function
+
+    png_set_user_transform_info(png_ptr, user_ptr,
+        user_depth, user_channels);
+
+The user's application, not libpng, is responsible for allocating and
+freeing any memory required for the user structure.
+
+You can retrieve the pointer via the function
+png_get_user_transform_ptr().  For example:
+
+    voidp read_user_transform_ptr =
+        png_get_user_transform_ptr(png_ptr);
+
+The last thing to handle is interlacing; this is covered in detail below,
+but you must call the function here if you want libpng to handle expansion
+of the interlaced image.
+
+    number_of_passes = png_set_interlace_handling(png_ptr);
+
+After setting the transformations, libpng can update your png_info
+structure to reflect any transformations you've requested with this
+call.
+
+    png_read_update_info(png_ptr, info_ptr);
+
+This is most useful to update the info structure's rowbytes
+field so you can use it to allocate your image memory.  This function
+will also update your palette with the correct screen_gamma and
+background if these have been given with the calls above.  You may
+only call png_read_update_info() once with a particular info_ptr.
+
+After you call png_read_update_info(), you can allocate any
+memory you need to hold the image.  The row data is simply
+raw byte data for all forms of images.  As the actual allocation
+varies among applications, no example will be given.  If you
+are allocating one large chunk, you will need to build an
+array of pointers to each row, as it will be needed for some
+of the functions below.
+
+Be sure that your platform can allocate the buffer that you'll need.
+libpng internally checks for oversize width, but you'll need to
+do your own check for number_of_rows*width*pixel_size if you are using
+a multiple-row buffer:
+
+   /* Guard against integer overflow */
+   if (number_of_rows > PNG_SIZE_MAX/(width*pixel_size))
+      png_error(png_ptr, "image_data buffer would be too large");
+
+Remember: Before you call png_read_update_info(), the png_get_*()
+functions return the values corresponding to the original PNG image.
+After you call png_read_update_info the values refer to the image
+that libpng will output.  Consequently you must call all the png_set_
+functions before you call png_read_update_info().  This is particularly
+important for png_set_interlace_handling() - if you are going to call
+png_read_update_info() you must call png_set_interlace_handling() before
+it unless you want to receive interlaced output.
+
+Reading image data
+
+After you've allocated memory, you can read the image data.
+The simplest way to do this is in one function call.  If you are
+allocating enough memory to hold the whole image, you can just
+call png_read_image() and libpng will read in all the image data
+and put it in the memory area supplied.  You will need to pass in
+an array of pointers to each row.
+
+This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() (unless you call
+png_read_update_info()) or call this function multiple times, or any
+of that other stuff necessary with png_read_rows().
+
+   png_read_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+   png_bytep row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to read in the whole image at once, you can
+use png_read_rows() instead.  If there is no interlacing (check
+interlace_type == PNG_INTERLACE_NONE), this is simple:
+
+    png_read_rows(png_ptr, row_pointers, NULL,
+        number_of_rows);
+
+where row_pointers is the same as in the png_read_image() call.
+
+If you are doing this just one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+    png_bytep row_pointer = row;
+    png_read_row(png_ptr, row_pointer, NULL);
+
+If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
+get somewhat harder.  The only current (PNG Specification version 1.2)
+interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
+a somewhat complicated 2D interlace scheme, known as Adam7, that
+breaks down an image into seven smaller images of varying size, based
+on an 8x8 grid.  This number is defined (from libpng 1.5) as
+PNG_INTERLACE_ADAM7_PASSES in png.h
+
+libpng can fill out those images or it can give them to you "as is".
+It is almost always better to have libpng handle the interlacing for you.
+If you want the images filled out, there are two ways to do that.  The one
+mentioned in the PNG specification is to expand each pixel to cover
+those pixels that have not been read yet (the "rectangle" method).
+This results in a blocky image for the first pass, which gradually
+smooths out as more pixels are read.  The other method is the "sparkle"
+method, where pixels are drawn only in their final locations, with the
+rest of the image remaining whatever colors they were initialized to
+before the start of the read.  The first method usually looks better,
+but tends to be slower, as there are more pixels to put in the rows.
+
+If, as is likely, you want libpng to expand the images, call this before
+calling png_start_read_image() or png_read_update_info():
+
+    if (interlace_type == PNG_INTERLACE_ADAM7)
+       number_of_passes
+           = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed.  Currently, this is seven,
+but may change if another interlace type is added.  This function can be
+called even if the file is not interlaced, where it will return one pass.
+You then need to read the whole image 'number_of_passes' times.  Each time
+will distribute the pixels from the current pass to the correct place in
+the output image, so you need to supply the same rows to png_read_rows in
+each pass.
+
+If you are not going to display the image after each pass, but are
+going to wait until the entire image is read in, use the sparkle
+effect.  This effect is faster and the end result of either method
+is exactly the same.  If you are planning on displaying the image
+after each pass, the "rectangle" effect is generally considered the
+better looking one.
+
+If you only want the "sparkle" effect, just call png_read_row() or
+png_read_rows() as
+normal, with the third parameter NULL.  Make sure you make pass over
+the image number_of_passes times, and you don't change the data in the
+rows between calls.  You can change the locations of the data, just
+not the data.  Each pass only writes the pixels appropriate for that
+pass, and assumes the data from previous passes is still valid.
+
+    png_read_rows(png_ptr, row_pointers, NULL,
+        number_of_rows);
+    or
+    png_read_row(png_ptr, row_pointers, NULL);
+
+If you only want the first effect (the rectangles), do the same as
+before except pass the row buffer in the third parameter, and leave
+the second parameter NULL.
+
+    png_read_rows(png_ptr, NULL, row_pointers,
+        number_of_rows);
+    or
+    png_read_row(png_ptr, NULL, row_pointers);
+
+If you don't want libpng to handle the interlacing details, just call
+png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
+Each of the images is a valid image by itself; however, you will almost
+certainly need to distribute the pixels from each sub-image to the
+correct place.  This is where everything gets very tricky.
+
+If you want to retrieve the separate images you must pass the correct
+number of rows to each successive call of png_read_rows().  The calculation
+gets pretty complicated for small images, where some sub-images may
+not even exist because either their width or height ends up zero.
+libpng provides two macros to help you in 1.5 and later versions:
+
+   png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
+   png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
+
+Respectively these tell you the width and height of the sub-image
+corresponding to the numbered pass.  'pass' is in in the range 0 to 6 -
+this can be confusing because the specification refers to the same passes
+as 1 to 7!  Be careful, you must check both the width and height before
+calling png_read_rows() and not call it for that pass if either is zero.
+
+You can, of course, read each sub-image row by row.  If you want to
+produce optimal code to make a pixel-by-pixel transformation of an
+interlaced image this is the best approach; read each row of each pass,
+transform it, and write it out to a new interlaced image.
+
+If you want to de-interlace the image yourself libpng provides further
+macros to help that tell you where to place the pixels in the output image.
+Because the interlacing scheme is rectangular - sub-image pixels are always
+arranged on a rectangular grid - all you need to know for each pass is the
+starting column and row in the output image of the first pixel plus the
+spacing between each pixel.  As of libpng 1.5 there are four macros to
+retrieve this information:
+
+   png_uint_32 x = PNG_PASS_START_COL(pass);
+   png_uint_32 y = PNG_PASS_START_ROW(pass);
+   png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
+   png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
+
+These allow you to write the obvious loop:
+
+   png_uint_32 input_y = 0;
+   png_uint_32 output_y = PNG_PASS_START_ROW(pass);
+
+   while (output_y < output_image_height)
+   {
+      png_uint_32 input_x = 0;
+      png_uint_32 output_x = PNG_PASS_START_COL(pass);
+
+      while (output_x < output_image_width)
+      {
+         image[output_y][output_x] =
+             subimage[pass][input_y][input_x++];
+
+         output_x += xStep;
+      }
+
+      ++input_y;
+      output_y += yStep;
+   }
+
+Notice that the steps between successive output rows and columns are
+returned as shifts.  This is possible because the pixels in the subimages
+are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
+image.  In practice you may need to directly calculate the output coordinate
+given an input coordinate.  libpng provides two further macros for this
+purpose:
+
+   png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
+   png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
+
+Finally a pair of macros are provided to tell you if a particular image
+row or column appears in a given pass:
+
+   int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
+   int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
+
+Bear in mind that you will probably also need to check the width and height
+of the pass in addition to the above to be sure the pass even exists!
+
+With any luck you are convinced by now that you don't want to do your own
+interlace handling.  In reality normally the only good reason for doing this
+is if you are processing PNG files on a pixel-by-pixel basis and don't want
+to load the whole file into memory when it is interlaced.
+
+libpng includes a test program, pngvalid, that illustrates reading and
+writing of interlaced images.  If you can't get interlacing to work in your
+code and don't want to leave it to libpng (the recommended approach), see
+how pngvalid.c does it.
+
+Finishing a sequential read
+
+After you are finished reading the image through the
+low-level interface, you can finish reading the file.
+
+If you want to use a different crc action for handling CRC errors in
+chunks after the image data, you can call png_set_crc_action()
+again at this point.
+
+If you are interested in comments or time, which may be stored either
+before or after the image data, you should pass the separate png_info
+struct if you want to keep the comments from before and after the image
+separate.
+
+    png_infop end_info = png_create_info_struct(png_ptr);
+
+    if (!end_info)
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+       return ERROR;
+    }
+
+    png_read_end(png_ptr, end_info);
+
+If you are not interested, you should still call png_read_end()
+but you can pass NULL, avoiding the need to create an end_info structure.
+If you do this, libpng will not process any chunks after IDAT other than
+skipping over them and perhaps (depending on whether you have called
+png_set_crc_action) checking their CRCs while looking for the IEND chunk.
+
+   png_read_end(png_ptr, NULL);
+
+If you don't call png_read_end(), then your file pointer will be
+left pointing to the first chunk after the last IDAT, which is probably
+not what you want if you expect to read something beyond the end of
+the PNG datastream.
+
+When you are done, you can free all memory allocated by libpng like this:
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
+
+or, if you didn't create an end_info structure,
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+    png_free_data(png_ptr, info_ptr, mask, seq)
+
+    mask - identifies data to be freed, a mask
+           containing the bitwise OR of one or
+           more of
+             PNG_FREE_PLTE, PNG_FREE_TRNS,
+             PNG_FREE_HIST, PNG_FREE_ICCP,
+             PNG_FREE_PCAL, PNG_FREE_ROWS,
+             PNG_FREE_SCAL, PNG_FREE_SPLT,
+             PNG_FREE_TEXT, PNG_FREE_UNKN,
+           or simply PNG_FREE_ALL
+
+    seq  - sequence number of item to be freed
+           (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng,  and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed.  If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+The default behavior is only to free data that was allocated internally
+by libpng.  This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+    png_data_freer(png_ptr, info_ptr, freer, mask)
+
+    freer  - one of
+               PNG_DESTROY_WILL_FREE_DATA
+               PNG_SET_WILL_FREE_DATA
+               PNG_USER_WILL_FREE_DATA
+
+    mask   - which data elements are affected
+             same choices as in png_free_data()
+
+This function only affects data that has already been allocated.
+You can call this function after reading the PNG data but before calling
+any png_set_*() functions, to control whether the user or the png_set_*()
+function is responsible for freeing any existing data that might be present,
+and again after the png_set_*() functions to control whether the user
+or png_destroy_*() is supposed to free the data.  When the user assumes
+responsibility for libpng-allocated data, the application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated your row_pointers in a single block, as suggested above in
+the description of the high level read interface, you must not transfer
+responsibility for freeing it to the png_set_rows or png_read_destroy function,
+because they would also try to free the individual row_pointers[i].
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key.  Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+
+The png_free_data() function will turn off the "valid" flag for anything
+it frees.  If you need to turn the flag off for a chunk that was freed by
+your application instead of by libpng, you can use
+
+    png_set_invalid(png_ptr, info_ptr, mask);
+
+    mask - identifies the chunks to be made invalid,
+           containing the bitwise OR of one or
+           more of
+             PNG_INFO_gAMA, PNG_INFO_sBIT,
+             PNG_INFO_cHRM, PNG_INFO_PLTE,
+             PNG_INFO_tRNS, PNG_INFO_bKGD,
+             PNG_INFO_eXIf,
+             PNG_INFO_hIST, PNG_INFO_pHYs,
+             PNG_INFO_oFFs, PNG_INFO_tIME,
+             PNG_INFO_pCAL, PNG_INFO_sRGB,
+             PNG_INFO_iCCP, PNG_INFO_sPLT,
+             PNG_INFO_sCAL, PNG_INFO_IDAT
+
+For a more compact example of reading a PNG image, see the file example.c.
+
+Reading PNG files progressively
+
+The progressive reader is slightly different from the non-progressive
+reader.  Instead of calling png_read_info(), png_read_rows(), and
+png_read_end(), you make one call to png_process_data(), which calls
+callbacks when it has the info, a row, or the end of the image.  You
+set up these callbacks with png_set_progressive_read_fn().  You don't
+have to worry about the input/output functions of libpng, as you are
+giving the library the data directly in png_process_data().  I will
+assume that you have read the section on reading PNG files above,
+so I will only highlight the differences (although I will show
+all of the code).
+
+png_structp png_ptr;
+png_infop info_ptr;
+
+ /*  An example code fragment of how you would
+     initialize the progressive reader in your
+     application. */
+ int
+ initialize_png_reader()
+ {
+    png_ptr = png_create_read_struct
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+         user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+        return ERROR;
+
+    info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+    {
+       png_destroy_read_struct(&png_ptr, NULL, NULL);
+       return ERROR;
+    }
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+       return ERROR;
+    }
+
+    /* This one's new.  You can provide functions
+       to be called when the header info is valid,
+       when each row is completed, and when the image
+       is finished.  If you aren't using all functions,
+       you can specify NULL parameters.  Even when all
+       three functions are NULL, you need to call
+       png_set_progressive_read_fn().  You can use
+       any struct as the user_ptr (cast to a void pointer
+       for the function call), and retrieve the pointer
+       from inside the callbacks using the function
+
+          png_get_progressive_ptr(png_ptr);
+
+       which will return a void pointer, which you have
+       to cast appropriately.
+     */
+    png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
+        info_callback, row_callback, end_callback);
+
+    return 0;
+ }
+
+ /* A code fragment that you call as you receive blocks
+   of data */
+ int
+ process_data(png_bytep buffer, png_uint_32 length)
+ {
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+       return ERROR;
+    }
+
+    /* This one's new also.  Simply give it a chunk
+       of data from the file stream (in order, of
+       course).  On machines with segmented memory
+       models machines, don't give it any more than
+       64K.  The library seems to run fine with sizes
+       of 4K. Although you can give it much less if
+       necessary (I assume you can give it chunks of
+       1 byte, I haven't tried less than 256 bytes
+       yet).  When this function returns, you may
+       want to display any rows that were generated
+       in the row callback if you don't already do
+       so there.
+     */
+    png_process_data(png_ptr, info_ptr, buffer, length);
+
+    /* At this point you can call png_process_data_skip if
+       you want to handle data the library will skip yourself;
+       it simply returns the number of bytes to skip (and stops
+       libpng skipping that number of bytes on the next
+       png_process_data call).
+    return 0;
+ }
+
+ /* This function is called (as set by
+    png_set_progressive_read_fn() above) when enough data
+    has been supplied so all of the header has been
+    read.
+ */
+ void
+ info_callback(png_structp png_ptr, png_infop info)
+ {
+    /* Do any setup here, including setting any of
+       the transformations mentioned in the Reading
+       PNG files section.  For now, you _must_ call
+       either png_start_read_image() or
+       png_read_update_info() after all the
+       transformations are set (even if you don't set
+       any).  You may start getting rows before
+       png_process_data() returns, so this is your
+       last chance to prepare for that.
+
+       This is where you turn on interlace handling,
+       assuming you don't want to do it yourself.
+
+       If you need to you can stop the processing of
+       your original input data at this point by calling
+       png_process_data_pause.  This returns the number
+       of unprocessed bytes from the last png_process_data
+       call - it is up to you to ensure that the next call
+       sees these bytes again.  If you don't want to bother
+       with this you can get libpng to cache the unread
+       bytes by setting the 'save' parameter (see png.h) but
+       then libpng will have to copy the data internally.
+     */
+ }
+
+ /* This function is called when each row of image
+    data is complete */
+ void
+ row_callback(png_structp png_ptr, png_bytep new_row,
+    png_uint_32 row_num, int pass)
+ {
+    /* If the image is interlaced, and you turned
+       on the interlace handler, this function will
+       be called for every row in every pass.  Some
+       of these rows will not be changed from the
+       previous pass.  When the row is not changed,
+       the new_row variable will be NULL.  The rows
+       and passes are called in order, so you don't
+       really need the row_num and pass, but I'm
+       supplying them because it may make your life
+       easier.
+
+       If you did not turn on interlace handling then
+       the callback is called for each row of each
+       sub-image when the image is interlaced.  In this
+       case 'row_num' is the row in the sub-image, not
+       the row in the output image as it is in all other
+       cases.
+
+       For the non-NULL rows of interlaced images when
+       you have switched on libpng interlace handling,
+       you must call png_progressive_combine_row()
+       passing in the row and the old row.  You can
+       call this function for NULL rows (it will just
+       return) and for non-interlaced images (it just
+       does the memcpy for you) if it will make the
+       code easier.  Thus, you can just do this for
+       all cases if you switch on interlace handling;
+     */
+
+        png_progressive_combine_row(png_ptr, old_row,
+          new_row);
+
+    /* where old_row is what was displayed
+       previously for the row.  Note that the first
+       pass (pass == 0, really) will completely cover
+       the old row, so the rows do not have to be
+       initialized.  After the first pass (and only
+       for interlaced images), you will have to pass
+       the current row, and the function will combine
+       the old row and the new row.
+
+       You can also call png_process_data_pause in this
+       callback - see above.
+    */
+ }
+
+ void
+ end_callback(png_structp png_ptr, png_infop info)
+ {
+    /* This function is called after the whole image
+       has been read, including any chunks after the
+       image (up to and including the IEND).  You
+       will usually have the same info chunk as you
+       had in the header, although some data may have
+       been added to the comments and time fields.
+
+       Most people won't do much here, perhaps setting
+       a flag that marks the image as finished.
+     */
+ }
+
+
+
+IV. Writing
+
+Much of this is very similar to reading.  However, everything of
+importance is repeated here, so you won't have to constantly look
+back up in the reading section to understand writing.
+
+Setup
+
+You will want to do the I/O initialization before you get into libpng,
+so if it doesn't work, you don't have anything to undo. If you are not
+using the standard I/O functions, you will need to replace them with
+custom writing functions.  See the discussion under Customizing libpng.
+
+    FILE *fp = fopen(file_name, "wb");
+
+    if (!fp)
+       return ERROR;
+
+Next, png_struct and png_info need to be allocated and initialized.
+As these can be both relatively large, you may not want to store these
+on the stack, unless you have stack space to spare.  Of course, you
+will want to check if they return NULL.  If you are also reading,
+you won't want to name your read structure and your write structure
+both "png_ptr"; you can call them anything you like, such as
+"read_ptr" and "write_ptr".  Look at pngtest.c, for example.
+
+    png_structp png_ptr = png_create_write_struct
+       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+       return ERROR;
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr)
+    {
+       png_destroy_write_struct(&png_ptr, NULL);
+       return ERROR;
+    }
+
+If you want to use your own memory allocation routines,
+define PNG_USER_MEM_SUPPORTED and use
+png_create_write_struct_2() instead of png_create_write_struct():
+
+    png_structp png_ptr = png_create_write_struct_2
+       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn, (png_voidp)
+        user_mem_ptr, user_malloc_fn, user_free_fn);
+
+After you have these structures, you will need to set up the
+error handling.  When libpng encounters an error, it expects to
+longjmp() back to your routine.  Therefore, you will need to call
+setjmp() and pass the png_jmpbuf(png_ptr).  If you
+write the file from different routines, you will need to update
+the png_jmpbuf(png_ptr) every time you enter a new routine that will
+call a png_*() function.  See your documentation of setjmp/longjmp
+for your compiler for more information on setjmp/longjmp.  See
+the discussion on libpng error handling in the Customizing Libpng
+section below for more information on the libpng error handling.
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_write_struct(&png_ptr, &info_ptr);
+       fclose(fp);
+       return ERROR;
+    }
+    ...
+    return;
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+   png_set_check_for_invalid_index(png_ptr, 0);
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are written as-is by the encoder, resulting in an
+invalid PNG datastream as output.  In this case the application is
+responsible for ensuring that the pixel indexes are in range when it writes
+a PLTE chunk with fewer entries than the bit depth would allow.
+
+Now you need to set up the output code.  The default for libpng is to
+use the C function fwrite().  If you use this, you will need to pass a
+valid FILE * in the function png_init_io().  Be sure that the file is
+opened in binary mode.  Again, if you wish to handle writing data in
+another way, see the discussion on libpng I/O handling in the Customizing
+Libpng section below.
+
+    png_init_io(png_ptr, fp);
+
+If you are embedding your PNG into a datastream such as MNG, and don't
+want libpng to write the 8-byte signature, or if you have already
+written the signature in your application, use
+
+    png_set_sig_bytes(png_ptr, 8);
+
+to inform libpng that it should not write a signature.
+
+Write callbacks
+
+At this point, you can set up a callback function that will be
+called after each row has been written, which you can use to control
+a progress meter or the like.  It's demonstrated in pngtest.c.
+You must supply a function
+
+    void write_row_callback(png_structp png_ptr, png_uint_32 row,
+       int pass)
+    {
+       /* put your code here */
+    }
+
+(You can give it another name that you like instead of "write_row_callback")
+
+To inform libpng about your function, use
+
+    png_set_write_status_fn(png_ptr, write_row_callback);
+
+When this function is called the row has already been completely processed and
+it has also been written out.  The 'row' and 'pass' refer to the next row to be
+handled.  For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0.  For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes.  Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass-1', if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+You now have the option of modifying how the compression library will
+run.  The following functions are mainly for testing, but may be useful
+in some cases, like if you need to write PNG files extremely fast and
+are willing to give up some compression, or if you want to get the
+maximum possible compression at the expense of slower writing.  If you
+have no special needs in this area, let the library do what it wants by
+not calling this function at all, as it has been tuned to deliver a good
+speed/compression ratio. The second parameter to png_set_filter() is
+the filter method, for which the only valid values are 0 (as of the
+July 1999 PNG specification, version 1.2) or 64 (if you are writing
+a PNG datastream that is to be embedded in a MNG datastream).  The third
+parameter is a flag that indicates which filter type(s) are to be tested
+for each scanline.  See the PNG specification for details on the specific
+filter types.
+
+
+    /* turn on or off filtering, and/or choose
+       specific filters.  You can use either a single
+       PNG_FILTER_VALUE_NAME or the bitwise OR of one
+       or more PNG_FILTER_NAME masks.
+     */
+    png_set_filter(png_ptr, 0,
+       PNG_FILTER_NONE  | PNG_FILTER_VALUE_NONE |
+       PNG_FILTER_SUB   | PNG_FILTER_VALUE_SUB  |
+       PNG_FILTER_UP    | PNG_FILTER_VALUE_UP   |
+       PNG_FILTER_AVG   | PNG_FILTER_VALUE_AVG  |
+       PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
+       PNG_ALL_FILTERS  | PNG_FAST_FILTERS);
+
+If an application wants to start and stop using particular filters during
+compression, it should start out with all of the filters (to ensure that
+the previous row of pixels will be stored in case it's needed later),
+and then add and remove them after the start of compression.
+
+If you are writing a PNG datastream that is to be embedded in a MNG
+datastream, the second parameter can be either 0 or 64.
+
+The png_set_compression_*() functions interface to the zlib compression
+library, and should mostly be ignored unless you really know what you are
+doing.  The only generally useful call is png_set_compression_level()
+which changes how much time zlib spends on trying to compress the image
+data.  See the Compression Library (zlib.h and algorithm.txt, distributed
+with zlib) for details on the compression levels.
+
+    #include zlib.h
+
+    /* Set the zlib compression level */
+    png_set_compression_level(png_ptr,
+        Z_BEST_COMPRESSION);
+
+    /* Set other zlib parameters for compressing IDAT */
+    png_set_compression_mem_level(png_ptr, 8);
+    png_set_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_compression_window_bits(png_ptr, 15);
+    png_set_compression_method(png_ptr, 8);
+    png_set_compression_buffer_size(png_ptr, 8192)
+
+    /* Set zlib parameters for text compression
+     * If you don't call these, the parameters
+     * fall back on those defined for IDAT chunks
+     */
+    png_set_text_compression_mem_level(png_ptr, 8);
+    png_set_text_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_text_compression_window_bits(png_ptr, 15);
+    png_set_text_compression_method(png_ptr, 8);
+
+Setting the contents of info for output
+
+You now need to fill in the png_info structure with all the data you
+wish to write before the actual image.  Note that the only thing you
+are allowed to write after the image is the text chunks and the time
+chunk (as of PNG Specification 1.2, anyway).  See png_write_end() and
+the latest PNG specification for more information on that.  If you
+wish to write them before the image, fill them in now, and flag that
+data as being valid.  If you want to wait until after the data, don't
+fill them until png_write_end().  For all the fields in png_info and
+their data types, see png.h.  For explanations of what the fields
+contain, see the PNG specification.
+
+Some of the more important parts of the png_info are:
+
+    png_set_IHDR(png_ptr, info_ptr, width, height,
+       bit_depth, color_type, interlace_type,
+       compression_type, filter_method)
+
+    width          - holds the width of the image
+                     in pixels (up to 2^31).
+
+    height         - holds the height of the image
+                     in pixels (up to 2^31).
+
+    bit_depth      - holds the bit depth of one of the
+                     image channels.
+                     (valid values are 1, 2, 4, 8, 16
+                     and depend also on the
+                     color_type.  See also significant
+                     bits (sBIT) below).
+
+    color_type     - describes which color/alpha
+                     channels are present.
+                     PNG_COLOR_TYPE_GRAY
+                        (bit depths 1, 2, 4, 8, 16)
+                     PNG_COLOR_TYPE_GRAY_ALPHA
+                        (bit depths 8, 16)
+                     PNG_COLOR_TYPE_PALETTE
+                        (bit depths 1, 2, 4, 8)
+                     PNG_COLOR_TYPE_RGB
+                        (bit_depths 8, 16)
+                     PNG_COLOR_TYPE_RGB_ALPHA
+                        (bit_depths 8, 16)
+
+                     PNG_COLOR_MASK_PALETTE
+                     PNG_COLOR_MASK_COLOR
+                     PNG_COLOR_MASK_ALPHA
+
+    interlace_type - PNG_INTERLACE_NONE or
+                     PNG_INTERLACE_ADAM7
+
+    compression_type - (must be
+                     PNG_COMPRESSION_TYPE_DEFAULT)
+
+    filter_method  - (must be PNG_FILTER_TYPE_DEFAULT
+                     or, if you are writing a PNG to
+                     be embedded in a MNG datastream,
+                     can also be
+                     PNG_INTRAPIXEL_DIFFERENCING)
+
+If you call png_set_IHDR(), the call must appear before any of the
+other png_set_*() functions, because they might require access to some of
+the IHDR settings.  The remaining png_set_*() functions can be called
+in any order.
+
+If you wish, you can reset the compression_type, interlace_type, or
+filter_method later by calling png_set_IHDR() again; if you do this, the
+width, height, bit_depth, and color_type must be the same in each call.
+
+    png_set_PLTE(png_ptr, info_ptr, palette,
+       num_palette);
+
+    palette        - the palette for the file
+                     (array of png_color)
+    num_palette    - number of entries in the palette
+
+
+    png_set_gAMA(png_ptr, info_ptr, file_gamma);
+    png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
+
+    file_gamma     - the gamma at which the image was
+                     created (PNG_INFO_gAMA)
+
+    int_file_gamma - 100,000 times the gamma at which
+                     the image was created
+
+    png_set_cHRM(png_ptr, info_ptr,  white_x, white_y, red_x, red_y,
+                     green_x, green_y, blue_x, blue_y)
+    png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X,
+                     green_Y, green_Z, blue_X, blue_Y, blue_Z)
+    png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y,
+                     int_red_x, int_red_y, int_green_x, int_green_y,
+                     int_blue_x, int_blue_y)
+    png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y,
+                     int_red_Z, int_green_X, int_green_Y, int_green_Z,
+                     int_blue_X, int_blue_Y, int_blue_Z)
+
+    {white,red,green,blue}_{x,y}
+                     A color space encoding specified using the chromaticities
+                     of the end points and the white point.
+
+    {red,green,blue}_{X,Y,Z}
+                     A color space encoding specified using the encoding end
+                     points - the CIE tristimulus specification of the intended
+                     color of the red, green and blue channels in the PNG RGB
+                     data.  The white point is simply the sum of the three end
+                     points.
+
+    png_set_sRGB(png_ptr, info_ptr, srgb_intent);
+
+    srgb_intent    - the rendering intent
+                     (PNG_INFO_sRGB) The presence of
+                     the sRGB chunk means that the pixel
+                     data is in the sRGB color space.
+                     This chunk also implies specific
+                     values of gAMA and cHRM.  Rendering
+                     intent is the CSS-1 property that
+                     has been defined by the International
+                     Color Consortium
+                     (http://www.color.org).
+                     It can be one of
+                     PNG_sRGB_INTENT_SATURATION,
+                     PNG_sRGB_INTENT_PERCEPTUAL,
+                     PNG_sRGB_INTENT_ABSOLUTE, or
+                     PNG_sRGB_INTENT_RELATIVE.
+
+
+    png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
+       srgb_intent);
+
+    srgb_intent    - the rendering intent
+                     (PNG_INFO_sRGB) The presence of the
+                     sRGB chunk means that the pixel
+                     data is in the sRGB color space.
+                     This function also causes gAMA and
+                     cHRM chunks with the specific values
+                     that are consistent with sRGB to be
+                     written.
+
+    png_set_iCCP(png_ptr, info_ptr, name, compression_type,
+                       profile, proflen);
+
+    name             - The profile name.
+
+    compression_type - The compression type; always
+                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+                       You may give NULL to this argument to
+                       ignore it.
+
+    profile          - International Color Consortium color
+                       profile data. May contain NULs.
+
+    proflen          - length of profile data in bytes.
+
+    png_set_sBIT(png_ptr, info_ptr, sig_bit);
+
+    sig_bit        - the number of significant bits for
+                     (PNG_INFO_sBIT) each of the gray, red,
+                     green, and blue channels, whichever are
+                     appropriate for the given color type
+                     (png_color_16)
+
+    png_set_tRNS(png_ptr, info_ptr, trans_alpha,
+       num_trans, trans_color);
+
+    trans_alpha    - array of alpha (transparency)
+                     entries for palette (PNG_INFO_tRNS)
+
+    num_trans      - number of transparent entries
+                     (PNG_INFO_tRNS)
+
+    trans_color    - graylevel or color sample values
+                     (in order red, green, blue) of the
+                     single transparent color for
+                     non-paletted images (PNG_INFO_tRNS)
+
+    png_set_eXIf_1(png_ptr, info_ptr, num_exif, exif);
+
+    exif           - Exif profile (array of png_byte)
+                     (PNG_INFO_eXIf)
+
+    png_set_hIST(png_ptr, info_ptr, hist);
+
+    hist           - histogram of palette (array of
+                     png_uint_16) (PNG_INFO_hIST)
+
+    png_set_tIME(png_ptr, info_ptr, mod_time);
+
+    mod_time       - time image was last modified
+                     (PNG_INFO_tIME)
+
+    png_set_bKGD(png_ptr, info_ptr, background);
+
+    background     - background color (of type
+                     png_color_16p) (PNG_INFO_bKGD)
+
+    png_set_text(png_ptr, info_ptr, text_ptr, num_text);
+
+    text_ptr       - array of png_text holding image
+                     comments
+
+    text_ptr[i].compression - type of compression used
+                 on "text" PNG_TEXT_COMPRESSION_NONE
+                           PNG_TEXT_COMPRESSION_zTXt
+                           PNG_ITXT_COMPRESSION_NONE
+                           PNG_ITXT_COMPRESSION_zTXt
+    text_ptr[i].key   - keyword for comment.  Must contain
+                 1-79 characters.
+    text_ptr[i].text  - text comments for current
+                         keyword.  Can be NULL or empty.
+    text_ptr[i].text_length - length of text string,
+                 after decompression, 0 for iTXt
+    text_ptr[i].itxt_length - length of itxt string,
+                 after decompression, 0 for tEXt/zTXt
+    text_ptr[i].lang  - language of comment (NULL or
+                         empty for unknown).
+    text_ptr[i].translated_keyword  - keyword in UTF-8 (NULL
+                         or empty for unknown).
+
+    Note that the itxt_length, lang, and lang_key
+    members of the text_ptr structure only exist when the
+    library is built with iTXt chunk support.  Prior to
+    libpng-1.4.0 the library was built by default without
+    iTXt support. Also note that when iTXt is supported,
+    they contain NULL pointers when the "compression"
+    field contains PNG_TEXT_COMPRESSION_NONE or
+    PNG_TEXT_COMPRESSION_zTXt.
+
+    num_text       - number of comments
+
+    png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
+       num_spalettes);
+
+    palette_ptr    - array of png_sPLT_struct structures
+                     to be added to the list of palettes
+                     in the info structure.
+    num_spalettes  - number of palette structures to be
+                     added.
+
+    png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
+        unit_type);
+
+    offset_x  - positive offset from the left
+                     edge of the screen
+
+    offset_y  - positive offset from the top
+                     edge of the screen
+
+    unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+    png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
+        unit_type);
+
+    res_x       - pixels/unit physical resolution
+                  in x direction
+
+    res_y       - pixels/unit physical resolution
+                  in y direction
+
+    unit_type   - PNG_RESOLUTION_UNKNOWN,
+                  PNG_RESOLUTION_METER
+
+    png_set_sCAL(png_ptr, info_ptr, unit, width, height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+
+    height      - height of a pixel in physical scale units
+                  (width and height are doubles)
+
+    png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+                  expressed as a string
+
+    height      - height of a pixel in physical scale units
+                 (width and height are strings like "2.54")
+
+    png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
+       num_unknowns)
+
+    unknowns          - array of png_unknown_chunk
+                        structures holding unknown chunks
+    unknowns[i].name  - name of unknown chunk
+    unknowns[i].data  - data of unknown chunk
+    unknowns[i].size  - size of unknown chunk's data
+    unknowns[i].location - position to write chunk in file
+                           0: do not write chunk
+                           PNG_HAVE_IHDR: before PLTE
+                           PNG_HAVE_PLTE: before IDAT
+                           PNG_AFTER_IDAT: after IDAT
+
+The "location" member is set automatically according to
+what part of the output file has already been written.
+You can change its value after calling png_set_unknown_chunks()
+as demonstrated in pngtest.c.  Within each of the "locations",
+the chunks are sequenced according to their position in the
+structure (that is, the value of "i", which is the order in which
+the chunk was either read from the input file or defined with
+png_set_unknown_chunks).
+
+A quick word about text and num_text.  text is an array of png_text
+structures.  num_text is the number of valid structures in the array.
+Each png_text structure holds a language code, a keyword, a text value,
+and a compression type.
+
+The compression types have the same valid numbers as the compression
+types of the image data.  Currently, the only valid number is zero.
+However, you can store text either compressed or uncompressed, unlike
+images, which always have to be compressed.  So if you don't want the
+text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
+Because tEXt and zTXt chunks don't have a language field, if you
+specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
+any language code or translated keyword will not be written out.
+
+Until text gets around a few hundred bytes, it is not worth compressing it.
+After the text has been written out to the file, the compression type
+is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
+so that it isn't written out again at the end (in case you are calling
+png_write_end() with the same struct).
+
+The keywords that are given in the PNG Specification are:
+
+    Title            Short (one line) title or
+                     caption for image
+
+    Author           Name of image's creator
+
+    Description      Description of image (possibly long)
+
+    Copyright        Copyright notice
+
+    Creation Time    Time of original image creation
+                     (usually RFC 1123 format, see below)
+
+    Software         Software used to create the image
+
+    Disclaimer       Legal disclaimer
+
+    Warning          Warning of nature of content
+
+    Source           Device used to create the image
+
+    Comment          Miscellaneous comment; conversion
+                     from other image format
+
+The keyword-text pairs work like this.  Keywords should be short
+simple descriptions of what the comment is about.  Some typical
+keywords are found in the PNG specification, as is some recommendations
+on keywords.  You can repeat keywords in a file.  You can even write
+some text before the image and some after.  For example, you may want
+to put a description of the image before the image, but leave the
+disclaimer until after, so viewers working over modem connections
+don't have to wait for the disclaimer to go over the modem before
+they start seeing the image.  Finally, keywords should be full
+words, not abbreviations.  Keywords and text are in the ISO 8859-1
+(Latin-1) character set (a superset of regular ASCII) and can not
+contain NUL characters, and should not contain control or other
+unprintable characters.  To make the comments widely readable, stick
+with basic ASCII, and avoid machine specific character set extensions
+like the IBM-PC character set.  The keyword must be present, but
+you can leave off the text string on non-compressed pairs.
+Compressed pairs must have a text string, as only the text string
+is compressed anyway, so the compression would be meaningless.
+
+PNG supports modification time via the png_time structure.  Two
+conversion routines are provided, png_convert_from_time_t() for
+time_t and png_convert_from_struct_tm() for struct tm.  The
+time_t routine uses gmtime().  You don't have to use either of
+these, but if you wish to fill in the png_time structure directly,
+you should provide the time in universal time (GMT) if possible
+instead of your local time.  Note that the year number is the full
+year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
+that months start with 1.
+
+If you want to store the time of the original image creation, you should
+use a plain tEXt chunk with the "Creation Time" keyword.  This is
+necessary because the "creation time" of a PNG image is somewhat vague,
+depending on whether you mean the PNG file, the time the image was
+created in a non-PNG format, a still photo from which the image was
+scanned, or possibly the subject matter itself.  In order to facilitate
+machine-readable dates, it is recommended that the "Creation Time"
+tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
+although this isn't a requirement.  Unlike the tIME chunk, the
+"Creation Time" tEXt chunk is not expected to be automatically changed
+by the software.  To facilitate the use of RFC 1123 dates, a function
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
+convert from PNG time to an RFC 1123 format string.  The caller must provide
+a writeable buffer of at least 29 bytes.
+
+Writing unknown chunks
+
+You can use the png_set_unknown_chunks function to queue up private chunks
+for writing.  You give it a chunk name, location, raw data, and a size.  You
+also must use png_set_keep_unknown_chunks() to ensure that libpng will
+handle them.  That's all there is to it.  The chunks will be written by the
+next following png_write_info_before_PLTE, png_write_info, or png_write_end
+function, depending upon the specified location.  Any chunks previously
+read into the info structure's unknown-chunk list will also be written out
+in a sequence that satisfies the PNG specification's ordering rules.
+
+Here is an example of writing two private chunks, prVt and miNE:
+
+    #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+    /* Set unknown chunk data */
+    png_unknown_chunk unk_chunk[2];
+    strcpy((char *) unk_chunk[0].name, "prVt";
+    unk_chunk[0].data = (unsigned char *) "PRIVATE DATA";
+    unk_chunk[0].size = strlen(unk_chunk[0].data)+1;
+    unk_chunk[0].location = PNG_HAVE_IHDR;
+    strcpy((char *) unk_chunk[1].name, "miNE";
+    unk_chunk[1].data = (unsigned char *) "MY CHUNK DATA";
+    unk_chunk[1].size = strlen(unk_chunk[0].data)+1;
+    unk_chunk[1].location = PNG_AFTER_IDAT;
+    png_set_unknown_chunks(write_ptr, write_info_ptr,
+        unk_chunk, 2);
+    /* Needed because miNE is not safe-to-copy */
+    png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
+       (png_bytep) "miNE", 1);
+    # if PNG_LIBPNG_VER < 10600
+      /* Deal with unknown chunk location bug in 1.5.x and earlier */
+      png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
+      png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
+    # endif
+    # if PNG_LIBPNG_VER < 10500
+      /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
+       * one before IDAT and another after IDAT, so don't use it; only use
+       * PNG_HAVE_IHDR location.  This call resets the location previously
+       * set by assignment and png_set_unknown_chunk_location() for chunk 1.
+       */
+      png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
+    # endif
+    #endif
+
+The high-level write interface
+
+At this point there are two ways to proceed; through the high-level
+write interface, or through a sequence of low-level write operations.
+You can use the high-level interface if your image data is present
+in the info structure.  All defined output
+transformations are permitted, enabled by the following masks.
+
+    PNG_TRANSFORM_IDENTITY      No transformation
+    PNG_TRANSFORM_PACKING       Pack 1, 2 and 4-bit samples
+    PNG_TRANSFORM_PACKSWAP      Change order of packed
+                                pixels to LSB first
+    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
+    PNG_TRANSFORM_SHIFT         Normalize pixels to the
+                                sBIT depth
+    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
+                                to BGRA
+    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
+                                to AG
+    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
+                                to transparency
+    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
+    PNG_TRANSFORM_STRIP_FILLER        Strip out filler
+                                      bytes (deprecated).
+    PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
+                                      filler bytes
+    PNG_TRANSFORM_STRIP_FILLER_AFTER  Strip out trailing
+                                      filler bytes
+
+If you have valid image data in the info structure (you can use
+png_set_rows() to put image data in the info structure), simply do this:
+
+    png_write_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some set of
+transformation flags.  This call is equivalent to png_write_info(),
+followed the set of transformations indicated by the transform mask,
+then png_write_image(), and finally png_write_end().
+
+(The final parameter of this call is not yet used.  Someday it might point
+to transformation parameters required by some future output transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_write_png().
+
+The low-level write interface
+
+If you are going the low-level route instead, you are now ready to
+write all the file information up to the actual image data.  You do
+this with a call to png_write_info().
+
+    png_write_info(png_ptr, info_ptr);
+
+Note that there is one transformation you may need to do before
+png_write_info().  In PNG files, the alpha channel in an image is the
+level of opacity.  If your data is supplied as a level of transparency,
+you can invert the alpha channel before you write it, so that 0 is
+fully transparent and 255 (in 8-bit or paletted images) or 65535
+(in 16-bit images) is fully opaque, with
+
+    png_set_invert_alpha(png_ptr);
+
+This must appear before png_write_info() instead of later with the
+other transformations because in the case of paletted images the tRNS
+chunk data has to be inverted before the tRNS chunk is written.  If
+your image is not a paletted image, the tRNS data (which in such cases
+represents a single color to be rendered as transparent) won't need to
+be changed, and you can safely do this transformation after your
+png_write_info() call.
+
+If you need to write a private chunk that you want to appear before
+the PLTE chunk when PLTE is present, you can write the PNG info in
+two steps, and insert code to write your own chunk between them:
+
+    png_write_info_before_PLTE(png_ptr, info_ptr);
+    png_set_unknown_chunks(png_ptr, info_ptr, ...);
+    png_write_info(png_ptr, info_ptr);
+
+After you've written the file information, you can set up the library
+to handle any special transformations of the image data.  The various
+ways to transform the data will be described in the order that they
+should occur.  This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths.  Even though each transformation
+checks to see if it has data that it can do something with, you should
+make sure to only enable a transformation if it will be valid for the
+data.  For example, don't swap red and blue on grayscale data.
+
+PNG files store RGB pixels packed into 3 or 6 bytes.  This code tells
+the library to strip input data that has 4 or 8 bytes per pixel down
+to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
+bytes per pixel).
+
+    png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
+PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
+is stored XRGB or RGBX.
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit files.
+If the data is supplied at 1 pixel per byte, use this code, which will
+correctly pack the pixels into a single byte:
+
+    png_set_packing(png_ptr);
+
+PNG files reduce possible bit depths to 1, 2, 4, 8, and 16.  If your
+data is of another bit depth, you can write an sBIT chunk into the
+file so that decoders can recover the original data if desired.
+
+    /* Set the true bit depth of the image data */
+    if (color_type & PNG_COLOR_MASK_COLOR)
+    {
+       sig_bit.red = true_bit_depth;
+       sig_bit.green = true_bit_depth;
+       sig_bit.blue = true_bit_depth;
+    }
+
+    else
+    {
+       sig_bit.gray = true_bit_depth;
+    }
+
+    if (color_type & PNG_COLOR_MASK_ALPHA)
+    {
+       sig_bit.alpha = true_bit_depth;
+    }
+
+    png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+If the data is stored in the row buffer in a bit depth other than
+one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
+this will scale the values to appear to be the correct bit depth as
+is required by PNG.
+
+    png_set_shift(png_ptr, &sig_bit);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first).  This code would be used if they are
+supplied the other way (little-endian, i.e. least significant bits
+first, the way PCs store them):
+
+    if (bit_depth > 8)
+       png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+    if (bit_depth < 8)
+       png_set_packswap(png_ptr);
+
+PNG files store 3 color pixels in red, green, blue order.  This code
+would be used if they are supplied as blue, green, red:
+
+    png_set_bgr(png_ptr);
+
+PNG files describe monochrome as black being zero and white being
+one. This code would be used if the pixels are supplied with this reversed
+(black being one and white being zero):
+
+    png_set_invert_mono(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs.  This is done by setting a callback
+with
+
+    png_set_write_user_transform_fn(png_ptr,
+       write_transform_fn);
+
+You must supply the function
+
+    void write_transform_fn(png_structp png_ptr, png_row_infop
+       row_info, png_bytep data)
+
+See pngtest.c for a working example.  Your function will be called
+before any of the other transformations are processed.  If supported
+libpng also supplies an information routine that may be called from
+your callback:
+
+   png_get_current_row_number(png_ptr);
+   png_get_current_pass_number(png_ptr);
+
+This returns the current row passed to the transform.  With interlaced
+images the value returned is the row in the input sub-image image.  Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function.
+
+    png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
+
+The user_channels and user_depth parameters of this function are ignored
+when writing; you can set them to zero as shown.
+
+You can retrieve the pointer via the function png_get_user_transform_ptr().
+For example:
+
+    voidp write_user_transform_ptr =
+       png_get_user_transform_ptr(png_ptr);
+
+It is possible to have libpng flush any pending output, either manually,
+or automatically after a certain number of lines have been written.  To
+flush the output stream a single time call:
+
+    png_write_flush(png_ptr);
+
+and to have libpng flush the output stream periodically after a certain
+number of scanlines have been written, call:
+
+    png_set_flush(png_ptr, nrows);
+
+Note that the distance between rows is from the last time png_write_flush()
+was called, or the first row of the image if it has never been called.
+So if you write 50 lines, and then png_set_flush 25, it will flush the
+output on the next scanline, and every 25 lines thereafter, unless
+png_write_flush() is called before 25 more lines have been written.
+If nrows is too small (less than about 10 lines for a 640 pixel wide
+RGB image) the image compression may decrease noticeably (although this
+may be acceptable for real-time applications).  Infrequent flushing will
+only degrade the compression performance by a few percent over images
+that do not use flushing.
+
+Writing the image data
+
+That's it for the transformations.  Now you can write the image data.
+The simplest way to do this is in one function call.  If you have the
+whole image in memory, you can just call png_write_image() and libpng
+will write the image.  You will need to pass in an array of pointers to
+each row.  This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() or call this function multiple
+times, or any of that other stuff necessary with png_write_rows().
+
+    png_write_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+    png_byte *row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to write the whole image at once, you can
+use png_write_rows() instead.  If the file is not interlaced,
+this is simple:
+
+    png_write_rows(png_ptr, row_pointers,
+       number_of_rows);
+
+row_pointers is the same as in the png_write_image() call.
+
+If you are just writing one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+    png_bytep row_pointer = row;
+
+    png_write_row(png_ptr, row_pointer);
+
+When the file is interlaced, things can get a good deal more complicated.
+The only currently (as of the PNG Specification version 1.2, dated July
+1999) defined interlacing scheme for PNG files is the "Adam7" interlace
+scheme, that breaks down an image into seven smaller images of varying
+size.  libpng will build these images for you, or you can do them
+yourself.  If you want to build them yourself, see the PNG specification
+for details of which pixels to write when.
+
+If you don't want libpng to handle the interlacing details, just
+use png_set_interlace_handling() and call png_write_rows() the
+correct number of times to write all the sub-images
+(png_set_interlace_handling() returns the number of sub-images.)
+
+If you want libpng to build the sub-images, call this before you start
+writing any rows:
+
+    number_of_passes = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed.  Currently, this is seven,
+but may change if another interlace type is added.
+
+Then write the complete image number_of_passes times.
+
+    png_write_rows(png_ptr, row_pointers, number_of_rows);
+
+Think carefully before you write an interlaced image.  Typically code that
+reads such images reads all the image data into memory, uncompressed, before
+doing any processing.  Only code that can display an image on the fly can
+take advantage of the interlacing and even then the image has to be exactly
+the correct size for the output device, because scaling an image requires
+adjacent pixels and these are not available until all the passes have been
+read.
+
+If you do write an interlaced image you will hardly ever need to handle
+the interlacing yourself.  Call png_set_interlace_handling() and use the
+approach described above.
+
+The only time it is conceivable that you will really need to write an
+interlaced image pass-by-pass is when you have read one pass by pass and
+made some pixel-by-pixel transformation to it, as described in the read
+code above.  In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
+to determine the size of each sub-image in turn and simply write the rows
+you obtained from the read code.
+
+Finishing a sequential write
+
+After you are finished writing the image, you should finish writing
+the file.  If you are interested in writing comments or time, you should
+pass an appropriately filled png_info pointer.  If you are not interested,
+you can pass NULL.
+
+    png_write_end(png_ptr, info_ptr);
+
+When you are done, you can free all memory used by libpng like this:
+
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+    png_free_data(png_ptr, info_ptr, mask, seq)
+
+    mask  - identifies data to be freed, a mask
+            containing the bitwise OR of one or
+            more of
+              PNG_FREE_PLTE, PNG_FREE_TRNS,
+              PNG_FREE_HIST, PNG_FREE_ICCP,
+              PNG_FREE_PCAL, PNG_FREE_ROWS,
+              PNG_FREE_SCAL, PNG_FREE_SPLT,
+              PNG_FREE_TEXT, PNG_FREE_UNKN,
+            or simply PNG_FREE_ALL
+
+    seq   - sequence number of item to be freed
+            (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user  and not by libpng,  and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed.  If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+If you allocated data such as a palette that you passed in to libpng
+with png_set_*, you must not free it until just before the call to
+png_destroy_write_struct().
+
+The default behavior is only to free data that was allocated internally
+by libpng.  This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+    png_data_freer(png_ptr, info_ptr, freer, mask)
+
+    freer  - one of
+               PNG_DESTROY_WILL_FREE_DATA
+               PNG_SET_WILL_FREE_DATA
+               PNG_USER_WILL_FREE_DATA
+
+    mask   - which data elements are affected
+             same choices as in png_free_data()
+
+For example, to transfer responsibility for some data from a read structure
+to a write structure, you could use
+
+    png_data_freer(read_ptr, read_info_ptr,
+       PNG_USER_WILL_FREE_DATA,
+       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+    png_data_freer(write_ptr, write_info_ptr,
+       PNG_DESTROY_WILL_FREE_DATA,
+       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+thereby briefly reassigning responsibility for freeing to the user but
+immediately afterwards reassigning it once more to the write_destroy
+function.  Having done this, it would then be safe to destroy the read
+structure and continue to use the PLTE, tRNS, and hIST data in the write
+structure.
+
+This function only affects data that has already been allocated.
+You can call this function before calling after the png_set_*() functions
+to control whether the user or png_destroy_*() is supposed to free the data.
+When the user assumes responsibility for libpng-allocated data, the
+application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key.  Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+For a more compact example of writing a PNG image, see the file example.c.
+
+V. Simplified API
+
+The simplified API, which became available in libpng-1.6.0, hides the details
+of both libpng and the PNG file format itself.
+It allows PNG files to be read into a very limited number of
+in-memory bitmap formats or to be written from the same formats.  If these
+formats do not accommodate your needs then you can, and should, use the more
+sophisticated APIs above - these support a wide variety of in-memory formats
+and a wide variety of sophisticated transformations to those formats as well
+as a wide variety of APIs to manipulate ancillary information.
+
+To read a PNG file using the simplified API:
+
+  1) Declare a 'png_image' structure (see below) on the stack, set the
+     version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
+     (this is REQUIRED, your program may crash if you don't do it.)
+
+  2) Call the appropriate png_image_begin_read... function.
+
+  3) Set the png_image 'format' member to the required sample format.
+
+  4) Allocate a buffer for the image and, if required, the color-map.
+
+  5) Call png_image_finish_read to read the image and, if required, the
+     color-map into your buffers.
+
+There are no restrictions on the format of the PNG input itself; all valid
+color types, bit depths, and interlace methods are acceptable, and the
+input image is transformed as necessary to the requested in-memory format
+during the png_image_finish_read() step.  The only caveat is that if you
+request a color-mapped image from a PNG that is full-color or makes
+complex use of an alpha channel the transformation is extremely lossy and the
+result may look terrible.
+
+To write a PNG file using the simplified API:
+
+  1) Declare a 'png_image' structure on the stack and memset()
+     it to all zero.
+
+  2) Initialize the members of the structure that describe the
+     image, setting the 'format' member to the format of the
+     image samples.
+
+  3) Call the appropriate png_image_write... function with a
+     pointer to the image and, if necessary, the color-map to write
+     the PNG data.
+
+png_image is a structure that describes the in-memory format of an image
+when it is being read or defines the in-memory format of an image that you
+need to write.  The "png_image" structure contains the following members:
+
+   png_controlp opaque  Initialize to NULL, free with png_image_free
+   png_uint_32  version Set to PNG_IMAGE_VERSION
+   png_uint_32  width   Image width in pixels (columns)
+   png_uint_32  height  Image height in pixels (rows)
+   png_uint_32  format  Image format as defined below
+   png_uint_32  flags   A bit mask containing informational flags
+   png_uint_32  colormap_entries; Number of entries in the color-map
+   png_uint_32  warning_or_error;
+   char         message[64];
+
+In the event of an error or warning the "warning_or_error"
+field will be set to a non-zero value and the 'message' field will contain
+a '\0' terminated string with the libpng error or warning message.  If both
+warnings and an error were encountered, only the error is recorded.  If there
+are multiple warnings, only the first one is recorded.
+
+The upper 30 bits of the "warning_or_error" value are reserved; the low two
+bits contain a two bit code such that a value more than 1 indicates a failure
+in the API just called:
+
+   0 - no warning or error
+   1 - warning
+   2 - error
+   3 - error preceded by warning
+
+The pixels (samples) of the image have one to four channels whose components
+have original values in the range 0 to 1.0:
+
+  1: A single gray or luminance channel (G).
+  2: A gray/luminance channel and an alpha channel (GA).
+  3: Three red, green, blue color channels (RGB).
+  4: Three color channels and an alpha channel (RGBA).
+
+The channels are encoded in one of two ways:
+
+  a) As a small integer, value 0..255, contained in a single byte.  For the
+alpha channel the original value is simply value/255.  For the color or
+luminance channels the value is encoded according to the sRGB specification
+and matches the 8-bit format expected by typical display devices.
+
+The color/gray channels are not scaled (pre-multiplied) by the alpha
+channel and are suitable for passing to color management software.
+
+  b) As a value in the range 0..65535, contained in a 2-byte integer, in
+the native byte order of the platform on which the application is running.
+All channels can be converted to the original value by dividing by 65535; all
+channels are linear.  Color channels use the RGB encoding (RGB end-points) of
+the sRGB specification.  This encoding is identified by the
+PNG_FORMAT_FLAG_LINEAR flag below.
+
+When the simplified API needs to convert between sRGB and linear colorspaces,
+the actual sRGB transfer curve defined in the sRGB specification (see the
+article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+approximation used elsewhere in libpng.
+
+When an alpha channel is present it is expected to denote pixel coverage
+of the color or luminance channels and is returned as an associated alpha
+channel: the color/gray channels are scaled (pre-multiplied) by the alpha
+value.
+
+The samples are either contained directly in the image data, between 1 and 8
+bytes per pixel according to the encoding, or are held in a color-map indexed
+by bytes in the image data.  In the case of a color-map the color-map entries
+are individual samples, encoded as above, and the image data has one byte per
+pixel to select the relevant sample from the color-map.
+
+PNG_FORMAT_*
+
+The #defines to be used in png_image::format.  Each #define identifies a
+particular layout of channel data and, if present, alpha values.  There are
+separate defines for each of the two component encodings.
+
+A format is built up using single bit flag values.  All combinations are
+valid.  Formats can be built up from the flag values or you can use one of
+the predefined values below.  When testing formats always use the FORMAT_FLAG
+macros to test for individual features - future versions of the library may
+add new flags.
+
+When reading or writing color-mapped images the format should be set to the
+format of the entries in the color-map then png_image_{read,write}_colormap
+called to read or write the color-map and set the format correctly for the
+image data.  Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
+
+NOTE: libpng can be built with particular features disabled. If you see
+compiler errors because the definition of one of the following flags has been
+compiled out it is because libpng does not have the required support.  It is
+possible, however, for the libpng configuration to enable the format on just
+read or just write; in that case you may see an error at run time.
+You can guard against this by checking for the definition of the
+appropriate "_SUPPORTED" macro, one of:
+
+   PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
+
+   PNG_FORMAT_FLAG_ALPHA    format with an alpha channel
+   PNG_FORMAT_FLAG_COLOR    color format: otherwise grayscale
+   PNG_FORMAT_FLAG_LINEAR   2-byte channels else 1-byte
+   PNG_FORMAT_FLAG_COLORMAP image data is color-mapped
+   PNG_FORMAT_FLAG_BGR      BGR colors, else order is RGB
+   PNG_FORMAT_FLAG_AFIRST   alpha channel comes first
+
+Supported formats are as follows.  Future versions of libpng may support more
+formats; for compatibility with older versions simply check if the format
+macro is defined using #ifdef.  These defines describe the in-memory layout
+of the components of the pixels of the image.
+
+First the single byte (sRGB) formats:
+
+   PNG_FORMAT_GRAY
+   PNG_FORMAT_GA
+   PNG_FORMAT_AG
+   PNG_FORMAT_RGB
+   PNG_FORMAT_BGR
+   PNG_FORMAT_RGBA
+   PNG_FORMAT_ARGB
+   PNG_FORMAT_BGRA
+   PNG_FORMAT_ABGR
+
+Then the linear 2-byte formats.  When naming these "Y" is used to
+indicate a luminance (gray) channel.  The component order within the pixel
+is always the same - there is no provision for swapping the order of the
+components in the linear format.  The components are 16-bit integers in
+the native byte order for your platform, and there is no provision for
+swapping the bytes to a different endian condition.
+
+   PNG_FORMAT_LINEAR_Y
+   PNG_FORMAT_LINEAR_Y_ALPHA
+   PNG_FORMAT_LINEAR_RGB
+   PNG_FORMAT_LINEAR_RGB_ALPHA
+
+With color-mapped formats the image data is one byte for each pixel. The byte
+is an index into the color-map which is formatted as above.  To obtain a
+color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
+to one of the above definitions, or you can use one of the definitions below.
+
+   PNG_FORMAT_RGB_COLORMAP
+   PNG_FORMAT_BGR_COLORMAP
+   PNG_FORMAT_RGBA_COLORMAP
+   PNG_FORMAT_ARGB_COLORMAP
+   PNG_FORMAT_BGRA_COLORMAP
+   PNG_FORMAT_ABGR_COLORMAP
+
+PNG_IMAGE macros
+
+These are convenience macros to derive information from a png_image
+structure.  The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
+actual image sample values - either the entries in the color-map or the
+pixels in the image.  The PNG_IMAGE_PIXEL_ macros return corresponding values
+for the pixels and will always return 1 for color-mapped formats.  The
+remaining macros return information about the rows in the image and the
+complete image.
+
+NOTE: All the macros that take a png_image::format parameter are compile time
+constants if the format parameter is, itself, a constant.  Therefore these
+macros can be used in array declarations and case labels where required.
+Similarly the macros are also pre-processor constants (sizeof is not used) so
+they can be used in #if tests.
+
+  PNG_IMAGE_SAMPLE_CHANNELS(fmt)
+    Returns the total number of channels in a given format: 1..4
+
+  PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)
+    Returns the size in bytes of a single component of a pixel or color-map
+    entry (as appropriate) in the image: 1 or 2.
+
+  PNG_IMAGE_SAMPLE_SIZE(fmt)
+    This is the size of the sample data for one sample.  If the image is
+    color-mapped it is the size of one color-map entry (and image pixels are
+    one byte in size), otherwise it is the size of one image pixel.
+
+  PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)
+    The maximum size of the color-map required by the format expressed in a
+    count of components.  This can be used to compile-time allocate a
+    color-map:
+
+    png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
+
+    png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
+
+    Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+    information from one of the png_image_begin_read_ APIs and dynamically
+    allocate the required memory.
+
+  PNG_IMAGE_COLORMAP_SIZE(fmt)
+   The size of the color-map required by the format; this is the size of the
+   color-map buffer passed to the png_image_{read,write}_colormap APIs. It is
+   a fixed number determined by the format so can easily be allocated on the
+   stack if necessary.
+
+Corresponding information about the pixels
+
+  PNG_IMAGE_PIXEL_CHANNELS(fmt)
+   The number of separate channels (components) in a pixel; 1 for a
+   color-mapped image.
+
+  PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
+   The size, in bytes, of each component in a pixel; 1 for a color-mapped
+   image.
+
+  PNG_IMAGE_PIXEL_SIZE(fmt)
+   The size, in bytes, of a complete pixel; 1 for a color-mapped image.
+
+Information about the whole row, or whole image
+
+  PNG_IMAGE_ROW_STRIDE(image)
+   Returns the total number of components in a single row of the image; this
+   is the minimum 'row stride', the minimum count of components between each
+   row.  For a color-mapped image this is the minimum number of bytes in a
+   row.
+
+   If you need the stride measured in bytes, row_stride_bytes is
+   PNG_IMAGE_ROW_STRIDE(image) * PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)
+   plus any padding bytes that your application might need, for example
+   to start the next row on a 4-byte boundary.
+
+  PNG_IMAGE_BUFFER_SIZE(image, row_stride)
+   Return the size, in bytes, of an image buffer given a png_image and a row
+   stride - the number of components to leave space for in each row.
+
+  PNG_IMAGE_SIZE(image)
+   Return the size, in bytes, of the image in memory given just a png_image;
+   the row stride is the minimum stride required for the image.
+
+  PNG_IMAGE_COLORMAP_SIZE(image)
+   Return the size, in bytes, of the color-map of this image.  If the image
+   format is not a color-map format this will return a size sufficient for
+   256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
+   you don't want to allocate a color-map in this case.
+
+PNG_IMAGE_FLAG_*
+
+Flags containing additional information about the image are held in
+the 'flags' field of png_image.
+
+  PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01
+    This indicates that the RGB values of the in-memory bitmap do not
+    correspond to the red, green and blue end-points defined by sRGB.
+
+  PNG_IMAGE_FLAG_FAST == 0x02
+   On write emphasise speed over compression; the resultant PNG file will be
+   larger but will be produced significantly faster, particular for large
+   images.  Do not use this option for images which will be distributed, only
+   used it when producing intermediate files that will be read back in
+   repeatedly.  For a typical 24-bit image the option will double the read
+   speed at the cost of increasing the image size by 25%, however for many
+   more compressible images the PNG file can be 10 times larger with only a
+   slight speed gain.
+
+  PNG_IMAGE_FLAG_16BIT_sRGB == 0x04
+    On read if the image is a 16-bit per component image and there is no gAMA
+    or sRGB chunk assume that the components are sRGB encoded.  Notice that
+    images output by the simplified API always have gamma information; setting
+    this flag only affects the interpretation of 16-bit images from an
+    external source.  It is recommended that the application expose this flag
+    to the user; the user can normally easily recognize the difference between
+    linear and sRGB encoding.  This flag has no effect on write - the data
+    passed to the write APIs must have the correct encoding (as defined
+    above.)
+
+    If the flag is not set (the default) input 16-bit per component data is
+    assumed to be linear.
+
+    NOTE: the flag can only be set after the png_image_begin_read_ call,
+    because that call initializes the 'flags' field.
+
+READ APIs
+
+   The png_image passed to the read APIs must have been initialized by setting
+   the png_controlp field 'opaque' to NULL (or, better, memset the whole thing.)
+
+   int png_image_begin_read_from_file( png_imagep image,
+     const char *file_name)
+
+     The named file is opened for read and the image header
+     is filled in from the PNG header in the file.
+
+   int png_image_begin_read_from_stdio (png_imagep image,
+     FILE* file)
+
+      The PNG header is read from the stdio FILE object.
+
+   int png_image_begin_read_from_memory(png_imagep image,
+      png_const_voidp memory, size_t size)
+
+      The PNG header is read from the given memory buffer.
+
+   int png_image_finish_read(png_imagep image,
+      png_colorp background, void *buffer,
+      png_int_32 row_stride, void *colormap));
+
+      Finish reading the image into the supplied buffer and
+      clean up the png_image structure.
+
+      row_stride is the step, in png_byte or png_uint_16 units
+      as appropriate, between adjacent rows.  A positive stride
+      indicates that the top-most row is first in the buffer -
+      the normal top-down arrangement.  A negative stride
+      indicates that the bottom-most row is first in the buffer.
+
+      background need only be supplied if an alpha channel must
+      be removed from a png_byte format and the removal is to be
+      done by compositing on a solid color; otherwise it may be
+      NULL and any composition will be done directly onto the
+      buffer.  The value is an sRGB color to use for the
+      background, for grayscale output the green channel is used.
+
+      For linear output removing the alpha channel is always done
+      by compositing on black.
+
+   void png_image_free(png_imagep image)
+
+      Free any data allocated by libpng in image->opaque,
+      setting the pointer to NULL.  May be called at any time
+      after the structure is initialized.
+
+When the simplified API needs to convert between sRGB and linear colorspaces,
+the actual sRGB transfer curve defined in the sRGB specification (see the
+article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+approximation used elsewhere in libpng.
+
+WRITE APIS
+
+For write you must initialize a png_image structure to describe the image to
+be written:
+
+   version: must be set to PNG_IMAGE_VERSION
+   opaque: must be initialized to NULL
+   width: image width in pixels
+   height: image height in rows
+   format: the format of the data you wish to write
+   flags: set to 0 unless one of the defined flags applies; set
+      PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images
+      where the RGB values do not correspond to the colors in sRGB.
+   colormap_entries: set to the number of entries in the color-map (0 to 256)
+
+   int png_image_write_to_file, (png_imagep image,
+      const char *file, int convert_to_8bit, const void *buffer,
+      png_int_32 row_stride, const void *colormap));
+
+      Write the image to the named file.
+
+   int png_image_write_to_memory (png_imagep image, void *memory,
+      png_alloc_size_t * PNG_RESTRICT memory_bytes,
+      int convert_to_8_bit, const void *buffer, ptrdiff_t row_stride,
+      const void *colormap));
+
+      Write the image to memory.
+
+   int png_image_write_to_stdio(png_imagep image, FILE *file,
+      int convert_to_8_bit, const void *buffer,
+      png_int_32 row_stride, const void *colormap)
+
+      Write the image to the given (FILE*).
+
+With all write APIs if image is in one of the linear formats with
+(png_uint_16) data then setting convert_to_8_bit will cause the output to be
+a (png_byte) PNG gamma encoded according to the sRGB specification, otherwise
+a 16-bit linear encoded PNG file is written.
+
+With all APIs row_stride is handled as in the read APIs - it is the spacing
+from one row to the next in component sized units (float) and if negative
+indicates a bottom-up row layout in the buffer.  If you pass zero, libpng will
+calculate the row_stride for you from the width and number of channels.
+
+Note that the write API does not support interlacing, sub-8-bit pixels,
+indexed (paletted) images, or most ancillary chunks.
+
+VI. Modifying/Customizing libpng
+
+There are two issues here.  The first is changing how libpng does
+standard things like memory allocation, input/output, and error handling.
+The second deals with more complicated things like adding new chunks,
+adding new transformations, and generally changing how libpng works.
+Both of those are compile-time issues; that is, they are generally
+determined at the time the code is written, and there is rarely a need
+to provide the user with a means of changing them.
+
+Memory allocation, input/output, and error handling
+
+All of the memory allocation, input/output, and error handling in libpng
+goes through callbacks that are user-settable.  The default routines are
+in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively.  To change
+these functions, call the appropriate png_set_*_fn() function.
+
+Memory allocation is done through the functions png_malloc(), png_calloc(),
+and png_free().  The png_malloc() and png_free() functions currently just
+call the standard C functions and png_calloc() calls png_malloc() and then
+clears the newly allocated memory to zero; note that png_calloc(png_ptr, size)
+is not the same as the calloc(number, size) function provided by stdlib.h.
+There is limited support for certain systems with segmented memory
+architectures and the types of pointers declared by png.h match this; you
+will have to use appropriate pointers in your application.  If you prefer
+to use a different method of allocating and freeing data, you can use
+png_create_read_struct_2() or png_create_write_struct_2() to register your
+own functions as described above.  These functions also provide a void
+pointer that can be retrieved via
+
+    mem_ptr = png_get_mem_ptr(png_ptr);
+
+Your replacement memory functions must have prototypes as follows:
+
+    png_voidp malloc_fn(png_structp png_ptr,
+       png_alloc_size_t size);
+
+    void free_fn(png_structp png_ptr, png_voidp ptr);
+
+Your malloc_fn() must return NULL in case of failure.  The png_malloc()
+function will normally call png_error() if it receives a NULL from the
+system memory allocator or from your replacement malloc_fn().
+
+Your free_fn() will never be called with a NULL ptr, since libpng's
+png_free() checks for NULL before calling free_fn().
+
+Input/Output in libpng is done through png_read() and png_write(),
+which currently just call fread() and fwrite().  The FILE * is stored in
+png_struct and is initialized via png_init_io().  If you wish to change
+the method of I/O, the library supplies callbacks that you can set
+through the function png_set_read_fn() and png_set_write_fn() at run
+time, instead of calling the png_init_io() function.  These functions
+also provide a void pointer that can be retrieved via the function
+png_get_io_ptr().  For example:
+
+    png_set_read_fn(png_structp read_ptr,
+        voidp read_io_ptr, png_rw_ptr read_data_fn)
+
+    png_set_write_fn(png_structp write_ptr,
+        voidp write_io_ptr, png_rw_ptr write_data_fn,
+        png_flush_ptr output_flush_fn);
+
+    voidp read_io_ptr = png_get_io_ptr(read_ptr);
+    voidp write_io_ptr = png_get_io_ptr(write_ptr);
+
+The replacement I/O functions must have prototypes as follows:
+
+    void user_read_data(png_structp png_ptr,
+        png_bytep data, size_t length);
+
+    void user_write_data(png_structp png_ptr,
+        png_bytep data, size_t length);
+
+    void user_flush_data(png_structp png_ptr);
+
+The user_read_data() function is responsible for detecting and
+handling end-of-data errors.
+
+Supplying NULL for the read, write, or flush functions sets them back
+to using the default C stream functions, which expect the io_ptr to
+point to a standard *FILE structure.  It is probably a mistake
+to use NULL for one of write_data_fn and output_flush_fn but not both
+of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
+It is an error to read from a write stream, and vice versa.
+
+Error handling in libpng is done through png_error() and png_warning().
+Errors handled through png_error() are fatal, meaning that png_error()
+should never return to its caller.  Currently, this is handled via
+setjmp() and longjmp() (unless you have compiled libpng with
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
+but you could change this to do things like exit() if you should wish,
+as long as your function does not return.
+
+On non-fatal errors, png_warning() is called
+to print a warning message, and then control returns to the calling code.
+By default png_error() and png_warning() print a message on stderr via
+fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
+(because you don't want the messages) or PNG_NO_STDIO defined (because
+fprintf() isn't available).  If you wish to change the behavior of the error
+functions, you will need to set up your own message callbacks.  These
+functions are normally supplied at the time that the png_struct is created.
+It is also possible to redirect errors and warnings to your own replacement
+functions after png_create_*_struct() has been called by calling:
+
+    png_set_error_fn(png_structp png_ptr,
+        png_voidp error_ptr, png_error_ptr error_fn,
+        png_error_ptr warning_fn);
+
+If NULL is supplied for either error_fn or warning_fn, then the libpng
+default function will be used, calling fprintf() and/or longjmp() if a
+problem is encountered.  The replacement error functions should have
+parameters as follows:
+
+    void user_error_fn(png_structp png_ptr,
+        png_const_charp error_msg);
+
+    void user_warning_fn(png_structp png_ptr,
+        png_const_charp warning_msg);
+
+Then, within your user_error_fn or user_warning_fn, you can retrieve
+the error_ptr if you need it, by calling
+
+    png_voidp error_ptr = png_get_error_ptr(png_ptr);
+
+The motivation behind using setjmp() and longjmp() is the C++ throw and
+catch exception handling methods.  This makes the code much easier to write,
+as there is no need to check every return code of every function call.
+However, there are some uncertainties about the status of local variables
+after a longjmp, so the user may want to be careful about doing anything
+after setjmp returns non-zero besides returning itself.  Consult your
+compiler documentation for more details.  For an alternative approach, you
+may wish to use the "cexcept" facility (see https://cexcept.sourceforge.io/),
+which is illustrated in pngvalid.c and in contrib/visupng.
+
+Beginning in libpng-1.4.0, the png_set_benign_errors() API became available.
+You can use this to handle certain errors (normally handled as errors)
+as warnings.
+
+    png_set_benign_errors (png_ptr, int allowed);
+
+    allowed: 0: treat png_benign_error() as an error.
+             1: treat png_benign_error() as a warning.
+
+As of libpng-1.6.0, the default condition is to treat benign errors as
+warnings while reading and as errors while writing.
+
+Custom chunks
+
+If you need to read or write custom chunks, you may need to get deeper
+into the libpng code.  The library now has mechanisms for storing
+and writing chunks of unknown type; you can even declare callbacks
+for custom chunks.  However, this may not be good enough if the
+library code itself needs to know about interactions between your
+chunk and existing `intrinsic' chunks.
+
+If you need to write a new intrinsic chunk, first read the PNG
+specification. Acquire a first level of understanding of how it works.
+Pay particular attention to the sections that describe chunk names,
+and look at how other chunks were designed, so you can do things
+similarly.  Second, check out the sections of libpng that read and
+write chunks.  Try to find a chunk that is similar to yours and use
+it as a template.  More details can be found in the comments inside
+the code.  It is best to handle private or unknown chunks in a generic method,
+via callback functions, instead of by modifying libpng functions. This
+is illustrated in pngtest.c, which uses a callback function to handle a
+private "vpAg" chunk and the new "sTER" chunk, which are both unknown to
+libpng.
+
+If you wish to write your own transformation for the data, look through
+the part of the code that does the transformations, and check out some of
+the simpler ones to get an idea of how they work.  Try to find a similar
+transformation to the one you want to add and copy off of it.  More details
+can be found in the comments inside the code itself.
+
+Configuring for gui/windowing platforms:
+
+You will need to write new error and warning functions that use the GUI
+interface, as described previously, and set them to be the error and
+warning functions at the time that png_create_*_struct() is called,
+in order to have them available during the structure initialization.
+They can be changed later via png_set_error_fn().  On some compilers,
+you may also have to change the memory allocators (png_malloc, etc.).
+
+Configuring zlib:
+
+There are special functions to configure the compression.  Perhaps the
+most useful one changes the compression level, which currently uses
+input compression values in the range 0 - 9.  The library normally
+uses the default compression level (Z_DEFAULT_COMPRESSION = 6).  Tests
+have shown that for a large majority of images, compression values in
+the range 3-6 compress nearly as well as higher levels, and do so much
+faster.  For online applications it may be desirable to have maximum speed
+(Z_BEST_SPEED = 1).  With versions of zlib after v0.99, you can also
+specify no compression (Z_NO_COMPRESSION = 0), but this would create
+files larger than just storing the raw bitmap.  You can specify the
+compression level by calling:
+
+    #include zlib.h
+    png_set_compression_level(png_ptr, level);
+
+Another useful one is to reduce the memory level used by the library.
+The memory level defaults to 8, but it can be lowered if you are
+short on memory (running DOS, for example, where you only have 640K).
+Note that the memory level does have an effect on compression; among
+other things, lower levels will result in sections of incompressible
+data being emitted in smaller stored blocks, with a correspondingly
+larger relative overhead of up to 15% in the worst case.
+
+    #include zlib.h
+    png_set_compression_mem_level(png_ptr, level);
+
+The other functions are for configuring zlib.  They are not recommended
+for normal use and may result in writing an invalid PNG file.  See
+zlib.h for more information on what these mean.
+
+    #include zlib.h
+    png_set_compression_strategy(png_ptr,
+        strategy);
+
+    png_set_compression_window_bits(png_ptr,
+        window_bits);
+
+    png_set_compression_method(png_ptr, method);
+
+This controls the size of the IDAT chunks (default 8192):
+
+    png_set_compression_buffer_size(png_ptr, size);
+
+As of libpng version 1.5.4, additional APIs became
+available to set these separately for non-IDAT
+compressed chunks such as zTXt, iTXt, and iCCP:
+
+    #include zlib.h
+    #if PNG_LIBPNG_VER >= 10504
+    png_set_text_compression_level(png_ptr, level);
+
+    png_set_text_compression_mem_level(png_ptr, level);
+
+    png_set_text_compression_strategy(png_ptr,
+        strategy);
+
+    png_set_text_compression_window_bits(png_ptr,
+        window_bits);
+
+    png_set_text_compression_method(png_ptr, method);
+    #endif
+
+Controlling row filtering
+
+If you want to control whether libpng uses filtering or not, which
+filters are used, and how it goes about picking row filters, you
+can call one of these functions.  The selection and configuration
+of row filters can have a significant impact on the size and
+encoding speed and a somewhat lesser impact on the decoding speed
+of an image.  Filtering is enabled by default for RGB and grayscale
+images (with and without alpha), but not for paletted images nor
+for any images with bit depths less than 8 bits/pixel.
+
+The 'method' parameter sets the main filtering method, which is
+currently only '0' in the PNG 1.2 specification.  The 'filters'
+parameter sets which filter(s), if any, should be used for each
+scanline.  Possible values are PNG_ALL_FILTERS, PNG_NO_FILTERS,
+or PNG_FAST_FILTERS to turn filtering on and off, or to turn on
+just the fast-decoding subset of filters, respectively.
+
+Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
+PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
+ORed together with '|' to specify one or more filters to use.
+These filters are described in more detail in the PNG specification.
+If you intend to change the filter type during the course of writing
+the image, you should start with flags set for all of the filters
+you intend to use so that libpng can initialize its internal
+structures appropriately for all of the filter types.  (Note that this
+means the first row must always be adaptively filtered, because libpng
+currently does not allocate the filter buffers until png_write_row()
+is called for the first time.)
+
+    filters = PNG_NO_FILTERS;
+    filters = PNG_ALL_FILTERS;
+    filters = PNG_FAST_FILTERS;
+
+    or
+
+    filters = PNG_FILTER_NONE | PNG_FILTER_SUB |
+              PNG_FILTER_UP | PNG_FILTER_AVG |
+              PNG_FILTER_PAETH;
+
+    png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
+       filters);
+
+              The second parameter can also be
+              PNG_INTRAPIXEL_DIFFERENCING if you are
+              writing a PNG to be embedded in a MNG
+              datastream.  This parameter must be the
+              same as the value of filter_method used
+              in png_set_IHDR().
+
+Requesting debug printout
+
+The macro definition PNG_DEBUG can be used to request debugging
+printout.  Set it to an integer value in the range 0 to 3.  Higher
+numbers result in increasing amounts of debugging information.  The
+information is printed to the "stderr" file, unless another file
+name is specified in the PNG_DEBUG_FILE macro definition.
+
+When PNG_DEBUG > 0, the following functions (macros) become available:
+
+   png_debug(level, message)
+   png_debug1(level, message, p1)
+   png_debug2(level, message, p1, p2)
+
+in which "level" is compared to PNG_DEBUG to decide whether to print
+the message, "message" is the formatted string to be printed,
+and p1 and p2 are parameters that are to be embedded in the string
+according to printf-style formatting directives.  For example,
+
+   png_debug1(2, "foo=%d", foo);
+
+is expanded to
+
+   if (PNG_DEBUG > 2)
+      fprintf(PNG_DEBUG_FILE, "foo=%d\n", foo);
+
+When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
+can still use PNG_DEBUG to control your own debugging:
+
+   #ifdef PNG_DEBUG
+       fprintf(stderr, ...);
+   #endif
+
+When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
+having level = 0 will be printed.  There aren't any such statements in
+this version of libpng, but if you insert some they will be printed.
+
+VII. MNG support
+
+The MNG specification (available at http://www.libpng.org/pub/mng) allows
+certain extensions to PNG for PNG images that are embedded in MNG datastreams.
+Libpng can support some of these extensions.  To enable them, use the
+png_permit_mng_features() function:
+
+   feature_set = png_permit_mng_features(png_ptr, mask)
+
+   mask is a png_uint_32 containing the bitwise OR of the
+        features you want to enable.  These include
+        PNG_FLAG_MNG_EMPTY_PLTE
+        PNG_FLAG_MNG_FILTER_64
+        PNG_ALL_MNG_FEATURES
+
+   feature_set is a png_uint_32 that is the bitwise AND of
+      your mask with the set of MNG features that is
+      supported by the version of libpng that you are using.
+
+It is an error to use this function when reading or writing a standalone
+PNG file with the PNG 8-byte signature.  The PNG datastream must be wrapped
+in a MNG datastream.  As a minimum, it must have the MNG 8-byte signature
+and the MHDR and MEND chunks.  Libpng does not provide support for these
+or any other MNG chunks; your application must provide its own support for
+them.  You may wish to consider using libmng (available at
+https://www.libmng.com/) instead.
+
+VIII. Changes to Libpng from version 0.88
+
+It should be noted that versions of libpng later than 0.96 are not
+distributed by the original libpng author, Guy Schalnat, nor by
+Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
+distributed versions 0.89 through 0.96, but rather by another member
+of the original PNG Group, Glenn Randers-Pehrson.  Guy and Andreas are
+still alive and well, but they have moved on to other things.
+
+The old libpng functions png_read_init(), png_write_init(),
+png_info_init(), png_read_destroy(), and png_write_destroy() have been
+moved to PNG_INTERNAL in version 0.95 to discourage their use.  These
+functions will be removed from libpng version 1.4.0.
+
+The preferred method of creating and initializing the libpng structures is
+via the png_create_read_struct(), png_create_write_struct(), and
+png_create_info_struct() because they isolate the size of the structures
+from the application, allow version error checking, and also allow the
+use of custom error handling routines during the initialization, which
+the old functions do not.  The functions png_read_destroy() and
+png_write_destroy() do not actually free the memory that libpng
+allocated for these structs, but just reset the data structures, so they
+can be used instead of png_destroy_read_struct() and
+png_destroy_write_struct() if you feel there is too much system overhead
+allocating and freeing the png_struct for each image read.
+
+Setting the error callbacks via png_set_message_fn() before
+png_read_init() as was suggested in libpng-0.88 is no longer supported
+because this caused applications that do not use custom error functions
+to fail if the png_ptr was not initialized to zero.  It is still possible
+to set the error callbacks AFTER png_read_init(), or to change them with
+png_set_error_fn(), which is essentially the same function, but with a new
+name to force compilation errors with applications that try to use the old
+method.
+
+Support for the sCAL, iCCP, iTXt, and sPLT chunks was added at libpng-1.0.6;
+however, iTXt support was not enabled by default.
+
+Starting with version 1.0.7, you can find out which version of the library
+you are using at run-time:
+
+   png_uint_32 libpng_vn = png_access_version_number();
+
+The number libpng_vn is constructed from the major version, minor
+version with leading zero, and release number with leading zero,
+(e.g., libpng_vn for version 1.0.7 is 10007).
+
+Note that this function does not take a png_ptr, so you can call it
+before you've created one.
+
+You can also check which version of png.h you used when compiling your
+application:
+
+   png_uint_32 application_vn = PNG_LIBPNG_VER;
+
+IX. Changes to Libpng from version 1.0.x to 1.2.x
+
+Support for user memory management was enabled by default.  To
+accomplish this, the functions png_create_read_struct_2(),
+png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
+png_malloc_default(), and png_free_default() were added.
+
+Support for the iTXt chunk has been enabled by default as of
+version 1.2.41.
+
+Support for certain MNG features was enabled.
+
+Support for numbered error messages was added.  However, we never got
+around to actually numbering the error messages.  The function
+png_set_strip_error_numbers() was added (Note: the prototype for this
+function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
+builds of libpng-1.2.15.  It was restored in libpng-1.2.36).
+
+The png_malloc_warn() function was added at libpng-1.2.3.  This issues
+a png_warning and returns NULL instead of aborting when it fails to
+acquire the requested memory allocation.
+
+Support for setting user limits on image width and height was enabled
+by default.  The functions png_set_user_limits(), png_get_user_width_max(),
+and png_get_user_height_max() were added at libpng-1.2.6.
+
+The png_set_add_alpha() function was added at libpng-1.2.7.
+
+The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
+Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
+tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
+deprecated.
+
+A number of macro definitions in support of runtime selection of
+assembler code features (especially Intel MMX code support) were
+added at libpng-1.2.0:
+
+    PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
+    PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+    PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
+    PNG_ASM_FLAG_MMX_READ_INTERLACE
+    PNG_ASM_FLAG_MMX_READ_FILTER_SUB
+    PNG_ASM_FLAG_MMX_READ_FILTER_UP
+    PNG_ASM_FLAG_MMX_READ_FILTER_AVG
+    PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
+    PNG_ASM_FLAGS_INITIALIZED
+    PNG_MMX_READ_FLAGS
+    PNG_MMX_FLAGS
+    PNG_MMX_WRITE_FLAGS
+    PNG_MMX_FLAGS
+
+We added the following functions in support of runtime
+selection of assembler code features:
+
+    png_get_mmx_flagmask()
+    png_set_mmx_thresholds()
+    png_get_asm_flags()
+    png_get_mmx_bitdepth_threshold()
+    png_get_mmx_rowbytes_threshold()
+    png_set_asm_flags()
+
+We replaced all of these functions with simple stubs in libpng-1.2.20,
+when the Intel assembler code was removed due to a licensing issue.
+
+These macros are deprecated:
+
+    PNG_READ_TRANSFORMS_NOT_SUPPORTED
+    PNG_PROGRESSIVE_READ_NOT_SUPPORTED
+    PNG_NO_SEQUENTIAL_READ_SUPPORTED
+    PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
+    PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
+    PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+They have been replaced, respectively, by:
+
+    PNG_NO_READ_TRANSFORMS
+    PNG_NO_PROGRESSIVE_READ
+    PNG_NO_SEQUENTIAL_READ
+    PNG_NO_WRITE_TRANSFORMS
+    PNG_NO_READ_ANCILLARY_CHUNKS
+    PNG_NO_WRITE_ANCILLARY_CHUNKS
+
+PNG_MAX_UINT was replaced with PNG_UINT_31_MAX.  It has been
+deprecated since libpng-1.0.16 and libpng-1.2.6.
+
+The function
+    png_check_sig(sig, num)
+was replaced with
+    png_sig_cmp(sig, 0, num) == 0
+It has been deprecated since libpng-0.90.
+
+The function
+    png_set_gray_1_2_4_to_8()
+which also expands tRNS to alpha was replaced with
+    png_set_expand_gray_1_2_4_to_8()
+which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
+
+X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+
+Private libpng prototypes and macro definitions were moved from
+png.h and pngconf.h into a new pngpriv.h header file.
+
+Functions png_set_benign_errors(), png_benign_error(), and
+png_chunk_benign_error() were added.
+
+Support for setting the maximum amount of memory that the application
+will allocate for reading chunks was added, as a security measure.
+The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
+were added to the library.
+
+We implemented support for I/O states by adding png_ptr member io_state
+and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+
+We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
+input transforms.
+
+Checking for and reporting of errors in the IHDR chunk is more thorough.
+
+Support for global arrays was removed, to improve thread safety.
+
+Some obsolete/deprecated macros and functions have been removed.
+
+Typecasted NULL definitions such as
+   #define png_voidp_NULL            (png_voidp)NULL
+were eliminated.  If you used these in your application, just use
+NULL instead.
+
+The png_struct and info_struct members "trans" and "trans_values" were
+changed to "trans_alpha" and "trans_color", respectively.
+
+The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
+were removed.
+
+The PNG_1_0_X and PNG_1_2_X macros were eliminated.
+
+The PNG_LEGACY_SUPPORTED macro was eliminated.
+
+Many WIN32_WCE #ifdefs were removed.
+
+The functions png_read_init(info_ptr), png_write_init(info_ptr),
+png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
+have been removed.  They have been deprecated since libpng-0.95.
+
+The png_permit_empty_plte() was removed. It has been deprecated
+since libpng-1.0.9.  Use png_permit_mng_features() instead.
+
+We removed the obsolete stub functions png_get_mmx_flagmask(),
+png_set_mmx_thresholds(), png_get_asm_flags(),
+png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
+png_set_asm_flags(), and png_mmx_supported()
+
+We removed the obsolete png_check_sig(), png_memcpy_check(), and
+png_memset_check() functions.  Instead use png_sig_cmp() == 0,
+memcpy(), and memset(), respectively.
+
+The function png_set_gray_1_2_4_to_8() was removed. It has been
+deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
+png_set_expand_gray_1_2_4_to_8() because the former function also
+expanded any tRNS chunk to an alpha channel.
+
+Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32
+were added and are used by default instead of the corresponding
+functions. Unfortunately,
+from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+
+We changed the prototype for png_malloc() from
+    png_malloc(png_structp png_ptr, png_uint_32 size)
+to
+    png_malloc(png_structp png_ptr, png_alloc_size_t size)
+
+This also applies to the prototype for the user replacement malloc_fn().
+
+The png_calloc() function was added and is used in place of
+of "png_malloc(); memset();" except in the case in png_read_png()
+where the array consists of pointers; in this case a "for" loop is used
+after the png_malloc() to set the pointers to NULL, to give robust.
+behavior in case the application runs out of memory part-way through
+the process.
+
+We changed the prototypes of png_get_compression_buffer_size() and
+png_set_compression_buffer_size() to work with size_t instead of
+png_uint_32.
+
+Support for numbered error messages was removed by default, since we
+never got around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was removed from the library by default.
+
+The png_zalloc() and png_zfree() functions are no longer exported.
+The png_zalloc() function no longer zeroes out the memory that it
+allocates.  Applications that called png_zalloc(png_ptr, number, size)
+can call png_calloc(png_ptr, number*size) instead, and can call
+png_free() instead of png_zfree().
+
+Support for dithering was disabled by default in libpng-1.4.0, because
+it has not been well tested and doesn't actually "dither".
+The code was not
+removed, however, and could be enabled by building libpng with
+PNG_READ_DITHER_SUPPORTED defined.  In libpng-1.4.2, this support
+was re-enabled, but the function was renamed png_set_quantize() to
+reflect more accurately what it actually does.  At the same time,
+the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
+PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED
+was renamed to PNG_READ_QUANTIZE_SUPPORTED.
+
+We removed the trailing '.' from the warning and error messages.
+
+XI. Changes to Libpng from version 1.4.x to 1.5.x
+
+From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+The incorrect macro was removed from libpng-1.4.5.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+   png_set_check_for_invalid_index(png_ptr, allowed);
+
+      allowed  - one of
+                 0: disable benign error (accept the
+                    invalid data without warning).
+                 1: enable benign error (treat the
+                    invalid data as an error or a
+                    warning).
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are decoded as opaque black by the decoder and written
+as-is by the encoder.
+
+Retrieving the maximum palette index found was added at libpng-1.5.15.
+This statement must appear after png_read_png() or png_read_image() while
+reading, and after png_write_png() or png_write_image() while writing.
+
+   int max_palette = png_get_palette_max(png_ptr, info_ptr);
+
+This will return the maximum palette index found in the image, or "-1" if
+the palette was not checked, or "0" if no palette was found.  Note that this
+does not account for any palette index used by ancillary chunks such as the
+bKGD chunk; you must check those separately to determine the maximum
+palette index actually used.
+
+There are no substantial API changes between the non-deprecated parts of
+the 1.4.5 API and the 1.5.0 API; however, the ability to directly access
+members of the main libpng control structures, png_struct and png_info,
+deprecated in earlier versions of libpng, has been completely removed from
+libpng 1.5, and new private "pngstruct.h", "pnginfo.h", and "pngdebug.h"
+header files were created.
+
+We no longer include zlib.h in png.h.  The include statement has been moved
+to pngstruct.h, where it is not accessible by applications. Applications that
+need access to information in zlib.h will need to add the '#include "zlib.h"'
+directive.  It does not matter whether this is placed prior to or after
+the '"#include png.h"' directive.
+
+The png_sprintf(), png_strcpy(), and png_strncpy() macros are no longer used
+and were removed.
+
+We moved the png_strlen(), png_memcpy(), png_memset(), and png_memcmp()
+macros into a private header file (pngpriv.h) that is not accessible to
+applications.
+
+In png_get_iCCP, the type of "profile" was changed from png_charpp
+to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep.
+
+There are changes of form in png.h, including new and changed macros to
+declare parts of the API.  Some API functions with arguments that are
+pointers to data not modified within the function have been corrected to
+declare these arguments with const.
+
+Much of the internal use of C macros to control the library build has also
+changed and some of this is visible in the exported header files, in
+particular the use of macros to control data and API elements visible
+during application compilation may require significant revision to
+application code.  (It is extremely rare for an application to do this.)
+
+Any program that compiled against libpng 1.4 and did not use deprecated
+features or access internal library structures should compile and work
+against libpng 1.5, except for the change in the prototype for
+png_get_iCCP() and png_set_iCCP() API functions mentioned above.
+
+libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of
+interlaced images.  The macros return the number of rows and columns in
+each pass and information that can be used to de-interlace and (if
+absolutely necessary) interlace an image.
+
+libpng 1.5.0 adds an API png_longjmp(png_ptr, value).  This API calls
+the application-provided png_longjmp_ptr on the internal, but application
+initialized, longjmp buffer.  It is provided as a convenience to avoid
+the need to use the png_jmpbuf macro, which had the unnecessary side
+effect of resetting the internal png_longjmp_ptr value.
+
+libpng 1.5.0 includes a complete fixed point API.  By default this is
+present along with the corresponding floating point API.  In general the
+fixed point API is faster and smaller than the floating point one because
+the PNG file format used fixed point, not floating point.  This applies
+even if the library uses floating point in internal calculations.  A new
+macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library
+uses floating point arithmetic (the default) or fixed point arithmetic
+internally for performance critical calculations such as gamma correction.
+In some cases, the gamma calculations may produce slightly different
+results.  This has changed the results in png_rgb_to_gray and in alpha
+composition (png_set_background for example). This applies even if the
+original image was already linear (gamma == 1.0) and, therefore, it is
+not necessary to linearize the image.  This is because libpng has *not*
+been changed to optimize that case correctly, yet.
+
+Fixed point support for the sCAL chunk comes with an important caveat;
+the sCAL specification uses a decimal encoding of floating point values
+and the accuracy of PNG fixed point values is insufficient for
+representation of these values. Consequently a "string" API
+(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
+arbitrary sCAL chunks in the absence of either the floating point API or
+internal floating point calculations.  Starting with libpng-1.5.0, both
+of these functions are present when PNG_sCAL_SUPPORTED is defined.  Prior
+to libpng-1.5.0, their presence also depended upon PNG_FIXED_POINT_SUPPORTED
+being defined and PNG_FLOATING_POINT_SUPPORTED not being defined.
+
+Applications no longer need to include the optional distribution header
+file pngusr.h or define the corresponding macros during application
+build in order to see the correct variant of the libpng API.  From 1.5.0
+application code can check for the corresponding _SUPPORTED macro:
+
+#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
+   /* code that uses the inch conversion APIs. */
+#endif
+
+This macro will only be defined if the inch conversion functions have been
+compiled into libpng.  The full set of macros, and whether or not support
+has been compiled in, are available in the header file pnglibconf.h.
+This header file is specific to the libpng build.  Notice that prior to
+1.5.0 the _SUPPORTED macros would always have the default definition unless
+reset by pngusr.h or by explicit settings on the compiler command line.
+These settings may produce compiler warnings or errors in 1.5.0 because
+of macro redefinition.
+
+Applications can now choose whether to use these macros or to call the
+corresponding function by defining PNG_USE_READ_MACROS or
+PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
+only supported from 1.5.0; defining PNG_NO_USE_READ_MACROS prior to 1.5.0
+will lead to a link failure.
+
+Prior to libpng-1.5.4, the zlib compressor used the same set of parameters
+when compressing the IDAT data and textual data such as zTXt and iCCP.
+In libpng-1.5.4 we reinitialized the zlib stream for each type of data.
+We added five png_set_text_*() functions for setting the parameters to
+use with textual data.
+
+Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+option was off by default, and slightly inaccurate scaling occurred.
+This option can no longer be turned off, and the choice of accurate
+or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
+API for accurate scaling or the old png_set_strip_16_to_8() API for simple
+chopping.  In libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+macro became PNG_READ_SCALE_16_TO_8_SUPPORTED, and the PNG_READ_16_TO_8
+macro became PNG_READ_STRIP_16_TO_8_SUPPORTED, to enable the two
+png_set_*_16_to_8() functions separately.
+
+Prior to libpng-1.5.4, the png_set_user_limits() function could only be
+used to reduce the width and height limits from the value of
+PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
+that it could be used to override them.  Now this function will reduce or
+increase the limits.
+
+Starting in libpng-1.5.22, default user limits were established. These
+can be overridden by application calls to png_set_user_limits(),
+png_set_user_chunk_cache_max(), and/or png_set_user_malloc_max().
+The limits are now
+                             max possible  default
+   png_user_width_max        0x7fffffff    1,000,000
+   png_user_height_max       0x7fffffff    1,000,000
+   png_user_chunk_cache_max  0 (unlimited) 1000
+   png_user_chunk_malloc_max 0 (unlimited) 8,000,000
+
+The png_set_option() function (and the "options" member of the png struct) was
+added to libpng-1.5.15, with option PNG_ARM_NEON.
+
+The library now supports a complete fixed point implementation and can
+thus be used on systems that have no floating point support or very
+limited or slow support.  Previously gamma correction, an essential part
+of complete PNG support, required reasonably fast floating point.
+
+As part of this the choice of internal implementation has been made
+independent of the choice of fixed versus floating point APIs and all the
+missing fixed point APIs have been implemented.
+
+The exact mechanism used to control attributes of API functions has
+changed, as described in the INSTALL file.
+
+A new test program, pngvalid, is provided in addition to pngtest.
+pngvalid validates the arithmetic accuracy of the gamma correction
+calculations and includes a number of validations of the file format.
+A subset of the full range of tests is run when "make check" is done
+(in the 'configure' build.)  pngvalid also allows total allocated memory
+usage to be evaluated and performs additional memory overwrite validation.
+
+Many changes to individual feature macros have been made. The following
+are the changes most likely to be noticed by library builders who
+configure libpng:
+
+1) All feature macros now have consistent naming:
+
+#define PNG_NO_feature turns the feature off
+#define PNG_feature_SUPPORTED turns the feature on
+
+pnglibconf.h contains one line for each feature macro which is either:
+
+#define PNG_feature_SUPPORTED
+
+if the feature is supported or:
+
+/*#undef PNG_feature_SUPPORTED*/
+
+if it is not.  Library code consistently checks for the 'SUPPORTED' macro.
+It does not, and libpng applications should not, check for the 'NO' macro
+which will not normally be defined even if the feature is not supported.
+The 'NO' macros are only used internally for setting or not setting the
+corresponding 'SUPPORTED' macros.
+
+Compatibility with the old names is provided as follows:
+
+PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED
+
+And the following definitions disable the corresponding feature:
+
+PNG_SETJMP_NOT_SUPPORTED disables SETJMP
+PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS
+PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV
+PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS
+PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS
+PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS
+
+Library builders should remove use of the above, inconsistent, names.
+
+2) Warning and error message formatting was previously conditional on
+the STDIO feature. The library has been changed to use the
+CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled
+the library no longer uses the printf(3) functions, even though the
+default read/write implementations use (FILE) style stdio.h functions.
+
+3) Three feature macros now control the fixed/floating point decisions:
+
+PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs
+
+PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in
+practice these are normally required internally anyway (because the PNG
+file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT
+merely stops the function from being exported.
+
+PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating
+point implementation or the fixed point one.  Typically the fixed point
+implementation is larger and slower than the floating point implementation
+on a system that supports floating point; however, it may be faster on a
+system which lacks floating point hardware and therefore uses a software
+emulation.
+
+4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the
+functions to read and write ints to be disabled independently of
+PNG_USE_READ_MACROS, which allows libpng to be built with the functions
+even though the default is to use the macros - this allows applications
+to choose at app buildtime whether or not to use macros (previously
+impossible because the functions weren't in the default build.)
+
+XII. Changes to Libpng from version 1.5.x to 1.6.x
+
+A "simplified API" has been added (see documentation in png.h and a simple
+example in contrib/examples/pngtopng.c).  The new publicly visible API
+includes the following:
+
+   macros:
+     PNG_FORMAT_*
+     PNG_IMAGE_*
+   structures:
+     png_control
+     png_image
+   read functions
+     png_image_begin_read_from_file()
+     png_image_begin_read_from_stdio()
+     png_image_begin_read_from_memory()
+     png_image_finish_read()
+     png_image_free()
+   write functions
+     png_image_write_to_file()
+     png_image_write_to_memory()
+     png_image_write_to_stdio()
+
+Starting with libpng-1.6.0, you can configure libpng to prefix all exported
+symbols, using the PNG_PREFIX macro.
+
+We no longer include string.h in png.h.  The include statement has been moved
+to pngpriv.h, where it is not accessible by applications.  Applications that
+need access to information in string.h must add an '#include <string.h>'
+directive.  It does not matter whether this is placed prior to or after
+the '#include "png.h"' directive.
+
+The following API are now DEPRECATED:
+   png_info_init_3()
+   png_convert_to_rfc1123() which has been replaced
+     with png_convert_to_rfc1123_buffer()
+   png_malloc_default()
+   png_free_default()
+   png_reset_zstream()
+
+The following have been removed:
+   png_get_io_chunk_name(), which has been replaced
+     with png_get_io_chunk_type().  The new
+     function returns a 32-bit integer instead of
+     a string.
+   The png_sizeof(), png_strlen(), png_memcpy(), png_memcmp(), and
+     png_memset() macros are no longer used in the libpng sources and
+     have been removed.  These had already been made invisible to applications
+     (i.e., defined in the private pngpriv.h header file) since libpng-1.5.0.
+
+The signatures of many exported functions were changed, such that
+   png_structp became png_structrp or png_const_structrp
+   png_infop became png_inforp or png_const_inforp
+where "rp" indicates a "restricted pointer".
+
+Dropped support for 16-bit platforms. The support for FAR/far types has
+been eliminated and the definition of png_alloc_size_t is now controlled
+by a flag so that 'small size_t' systems can select it if necessary.
+
+Error detection in some chunks has improved; in particular the iCCP chunk
+reader now does pretty complete validation of the basic format.  Some bad
+profiles that were previously accepted are now accepted with a warning or
+rejected, depending upon the png_set_benign_errors() setting, in particular
+the very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
+libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
+means of
+
+    #if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && \
+        defined(PNG_SET_OPTION_SUPPORTED)
+       png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE,
+           PNG_OPTION_ON);
+    #endif
+
+It's not a good idea to do this if you are using the "simplified API",
+which needs to be able to recognize sRGB profiles conveyed via the iCCP
+chunk.
+
+The PNG spec requirement that only grayscale profiles may appear in images
+with color type 0 or 4 and that even if the image only contains gray pixels,
+only RGB profiles may appear in images with color type 2, 3, or 6, is now
+enforced.  The sRGB chunk is allowed to appear in images with any color type
+and is interpreted by libpng to convey a one-tracer-curve gray profile or a
+three-tracer-curve RGB profile as appropriate.
+
+Libpng 1.5.x erroneously used /MD for Debug DLL builds; if you used the debug
+builds in your app and you changed your app to use /MD you will need to
+change it back to /MDd for libpng 1.6.x.
+
+Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
+an empty language field or an empty translated keyword.  Both of these
+are allowed by the PNG specification, so these warnings are no longer issued.
+
+The library now issues an error if the application attempts to set a
+transform after it calls png_read_update_info() or if it attempts to call
+both png_read_update_info() and png_start_read_image() or to call either
+of them more than once.
+
+The default condition for benign_errors is now to treat benign errors as
+warnings while reading and as errors while writing.
+
+The library now issues a warning if both background processing and RGB to
+gray are used when gamma correction happens. As with previous versions of
+the library the results are numerically very incorrect in this case.
+
+There are some minor arithmetic changes in some transforms such as
+png_set_background(), that might be detected by certain regression tests.
+
+Unknown chunk handling has been improved internally, without any API change.
+This adds more correct option control of the unknown handling, corrects
+a pre-existing bug where the per-chunk 'keep' setting is ignored, and makes
+it possible to skip IDAT chunks in the sequential reader.
+
+The machine-generated configure files are no longer included in branches
+libpng16 and later of the GIT repository.  They continue to be included
+in the tarball releases, however.
+
+Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT
+stream to set the size of the sliding window for reading instead of using the
+default 32-kbyte sliding window size.  It was discovered that there are
+hundreds of PNG files in the wild that have incorrect CMF bytes that caused
+zlib to issue the "invalid distance too far back" error and reject the file.
+Libpng-1.6.3 and later calculate their own safe CMF from the image dimensions,
+provide a way to revert to the libpng-1.5.x behavior (ignoring the CMF bytes
+and using a 32-kbyte sliding window), by using
+
+    png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW,
+        PNG_OPTION_ON);
+
+and provide a tool (contrib/tools/pngfix) for rewriting a PNG file while
+optimizing the CMF bytes in its IDAT chunk correctly.
+
+Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
+length, which resulted in PNG files that cannot be read beyond the bad iTXt
+chunk.  This error was fixed in libpng-1.6.3, and a tool (called
+contrib/tools/png-fix-itxt) has been added to the libpng distribution.
+
+Starting with libpng-1.6.17, the PNG_SAFE_LIMITS macro was eliminated
+and safe limits are used by default (users who need larger limits
+can still override them at compile time or run time, as described above).
+
+The new limits are
+                                default   spec limit
+   png_user_width_max         1,000,000  2,147,483,647
+   png_user_height_max        1,000,000  2,147,483,647
+   png_user_chunk_cache_max         128  unlimited
+   png_user_chunk_malloc_max  8,000,000  unlimited
+
+Starting with libpng-1.6.18, a PNG_RELEASE_BUILD macro was added, which allows
+library builders to control compilation for an installed system (a release build).
+It can be set for testing debug or beta builds to ensure that they will compile
+when the build type is switched to RC or STABLE. In essence this overrides the
+PNG_LIBPNG_BUILD_BASE_TYPE definition which is not directly user controllable.
+
+Starting with libpng-1.6.19, attempting to set an over-length PLTE chunk
+is an error. Previously this requirement of the PNG specification was not
+enforced, and the palette was always limited to 256 entries. An over-length
+PLTE chunk found in an input PNG is silently truncated.
+
+Starting with libpng-1.6.31, the eXIf chunk is supported. Libpng does not
+attempt to decode the Exif profile; it simply returns a byte array
+containing the profile to the calling application which must do its own
+decoding.
+
+XIII. Detecting libpng
+
+The png_get_io_ptr() function has been present since libpng-0.88, has never
+changed, and is unaffected by conditional compilation macros.  It is the
+best choice for use in configure scripts for detecting the presence of any
+libpng version since 0.88.  In an autoconf "configure.in" you could use
+
+    AC_CHECK_LIB(png, png_get_io_ptr, ...)
+
+XV. Source code repository
+
+Since about February 2009, version 1.2.34, libpng has been under "git" source
+control.  The git repository was built from old libpng-x.y.z.tar.gz files
+going back to version 0.70.  You can access the git repository (read only)
+at
+
+    https://github.com/pnggroup/libpng or
+    https://git.code.sf.net/p/libpng/code.git
+
+or you can browse it with a web browser at
+
+    https://github.com/pnggroup/libpng or
+    https://sourceforge.net/p/libpng/code/ci/libpng16/tree/
+
+Patches can be sent to png-mng-implement at lists.sourceforge.net or
+uploaded to the libpng bug tracker at
+
+    https://libpng.sourceforge.io/
+
+or as a "pull request" to
+
+    https://github.com/pnggroup/libpng/pulls
+
+We also accept patches built from the tar or zip distributions, and
+simple verbal descriptions of bug fixes, reported either to the
+SourceForge bug tracker, to the png-mng-implement at lists.sf.net
+mailing list, as github issues.
+
+XV. Coding style
+
+Our coding style is similar to the "Allman" style
+(See https://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
+braces on separate lines:
+
+    if (condition)
+    {
+       action;
+    }
+
+    else if (another condition)
+    {
+       another action;
+    }
+
+The braces can be omitted from simple one-line actions:
+
+    if (condition)
+       return 0;
+
+We use 3-space indentation, except for continued statements which
+are usually indented the same as the first line of the statement
+plus four more spaces.
+
+For macro definitions we use 2-space indentation, always leaving the "#"
+in the first column.
+
+    #ifndef PNG_NO_FEATURE
+    #  ifndef PNG_FEATURE_SUPPORTED
+    #    define PNG_FEATURE_SUPPORTED
+    #  endif
+    #endif
+
+Comments appear with the leading "/*" at the same indentation as
+the statement that follows the comment:
+
+    /* Single-line comment */
+    statement;
+
+    /* This is a multiple-line
+     * comment.
+     */
+    statement;
+
+Very short comments can be placed after the end of the statement
+to which they pertain:
+
+    statement;    /* comment */
+
+We don't use C++ style ("//") comments. We have, however,
+used them in the past in some now-abandoned MMX assembler
+code.
+
+Functions and their curly braces are not indented, and
+exported functions are marked with PNGAPI:
+
+ /* This is a public function that is visible to
+  * application programmers. It does thus-and-so.
+  */
+ void PNGAPI
+ png_exported_function(png_ptr, png_info, foo)
+ {
+    body;
+ }
+
+The return type and decorations are placed on a separate line
+ahead of the function name, as illustrated above.
+
+The prototypes for all exported functions appear in png.h,
+above the comment that says
+
+    /* Maintainer: Put new public prototypes here ... */
+
+We mark all non-exported functions with "/* PRIVATE */"":
+
+ void /* PRIVATE */
+ png_non_exported_function(png_ptr, png_info, foo)
+ {
+    body;
+ }
+
+The prototypes for non-exported functions (except for those in
+pngtest) appear in pngpriv.h above the comment that says
+
+  /* Maintainer: Put new private prototypes here ^ */
+
+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
+We put a space after the "sizeof" operator and we omit the
+optional parentheses around its argument when the argument
+is an expression, not a type name, and we always enclose the
+sizeof operator, with its argument, in parentheses:
+
+  (sizeof (png_uint_32))
+  (sizeof array)
+
+Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
+though it were a function.
+
+Control keywords if, for, while, and switch are always followed by a space
+to distinguish them from function calls, which have no trailing space.
+
+We put a space after each comma and after each semicolon
+in "for" statements, and we put spaces before and after each
+C binary operator and after "for" or "while", and before
+"?".  We don't put a space between a typecast and the expression
+being cast, nor do we put one between a function name and the
+left parenthesis that follows it:
+
+    for (i = 2; i > 0; --i)
+       y[i] = a(x) + (int)b;
+
+We prefer #ifdef and #ifndef to #if defined() and #if !defined()
+when there is only one macro being tested.  We always use parentheses
+with "defined".
+
+We express integer constants that are used as bit masks in hex format,
+with an even number of lower-case hex digits, and to make them unsigned
+(e.g., 0x00U, 0xffU, 0x0100U) and long if they are greater than 0x7fff
+(e.g., 0xffffUL).
+
+We prefer to use underscores rather than camelCase in names, except
+for a few type names that we inherit from zlib.h.
+
+We prefer "if (something != 0)" and "if (something == 0)" over
+"if (something)" and if "(!something)", respectively, and for pointers
+we prefer "if (some_pointer != NULL)" or "if (some_pointer == NULL)".
+
+We do not use the TAB character for indentation in the C sources.
+
+Lines do not exceed 80 characters.
+
+Other rules can be inferred by inspecting the libpng source.
Index: /trunk/src/libs/libpng-1.6.45/libpng.3
===================================================================
--- /trunk/src/libs/libpng-1.6.45/libpng.3	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/libpng.3	(revision 107811)
@@ -0,0 +1,6033 @@
+.TH LIBPNG 3 "February 23, 2024"
+.SH NAME
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.43
+
+.SH SYNOPSIS
+\fB#include <png.h>\fP
+
+\fBpng_uint_32 png_access_version_number (void);\fP
+
+\fBvoid png_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fBvoid png_build_grayscale_palette (int \fP\fIbit_depth\fP\fB, png_colorp \fIpalette\fP\fB);\fP
+
+\fBpng_voidp png_calloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fBvoid png_chunk_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fBvoid png_chunk_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fBvoid png_chunk_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
+
+\fBvoid png_convert_from_struct_tm (png_timep \fP\fIptime\fP\fB, struct tm FAR * \fIttime\fP\fB);\fP
+
+\fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP
+
+\fBpng_charp png_convert_to_rfc1123 (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fIptime\fP\fB);\fP
+
+\fBpng_infop png_create_info_struct (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_structp png_create_read_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
+
+\fBpng_structp png_create_read_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fBpng_structp png_create_write_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP
+
+\fBpng_structp png_create_write_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fBvoid png_data_freer (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIfreer\fP\fB, png_uint_32 \fImask\fP\fB);\fP
+
+\fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
+
+\fBvoid png_destroy_read_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fP\fIinfo_ptr_ptr\fP\fB, png_infopp \fIend_info_ptr_ptr\fP\fB);\fP
+
+\fBvoid png_destroy_write_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
+
+\fBvoid png_err (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
+
+\fBvoid png_free (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
+
+\fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_free_default (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
+
+\fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP
+
+\fBpng_byte png_get_bit_depth (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_bKGD (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fI*background\fP\fB);\fP
+
+\fBpng_byte png_get_channels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_cHRM (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*white_x\fP\fB, double \fP\fI*white_y\fP\fB, double \fP\fI*red_x\fP\fB, double \fP\fI*red_y\fP\fB, double \fP\fI*green_x\fP\fB, double \fP\fI*green_y\fP\fB, double \fP\fI*blue_x\fP\fB, double \fI*blue_y\fP\fB);\fP
+
+\fBpng_uint_32 png_get_cHRM_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*white_x\fP\fB, png_uint_32 \fP\fI*white_y\fP\fB, png_uint_32 \fP\fI*red_x\fP\fB, png_uint_32 \fP\fI*red_y\fP\fB, png_uint_32 \fP\fI*green_x\fP\fB, png_uint_32 \fP\fI*green_y\fP\fB, png_uint_32 \fP\fI*blue_x\fP\fB, png_uint_32 \fI*blue_y\fP\fB);\fP
+
+\fBpng_uint_32 png_get_cHRM_XYZ (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*red_X\fP\fB, double \fP\fI*red_Y\fP\fB, double \fP\fI*red_Z\fP\fB, double \fP\fI*green_X\fP\fB, double \fP\fI*green_Y\fP\fB, double \fP\fI*green_Z\fP\fB, double \fP\fI*blue_X\fP\fB, double \fP\fI*blue_Y\fP\fB, double \fI*blue_Z\fP\fB);\fP
+
+\fBpng_uint_32 png_get_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fI*int_red_X\fP\fB, png_fixed_point \fP\fI*int_red_Y\fP\fB, png_fixed_point \fP\fI*int_red_Z\fP\fB, png_fixed_point \fP\fI*int_green_X\fP\fB, png_fixed_point \fP\fI*int_green_Y\fP\fB, png_fixed_point \fP\fI*int_green_Z\fP\fB, png_fixed_point \fP\fI*int_blue_X\fP\fB, png_fixed_point \fP\fI*int_blue_Y\fP\fB, png_fixed_point \fI*int_blue_Z\fP\fB);\fP
+
+\fBpng_uint_32 png_get_chunk_cache_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_alloc_size_t png_get_chunk_malloc_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_color_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_compression_buffer_size (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_compression_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_copyright (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_current_row_number \fI(png_const_structp\fP\fB);\fP
+
+\fBpng_byte png_get_current_pass_number \fI(png_const_structp\fP\fB);\fP
+
+\fBpng_voidp png_get_error_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_filter_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_gAMA (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fI*file_gamma\fP\fB);\fP
+
+\fBpng_uint_32 png_get_gAMA_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fI*int_file_gamma\fP\fB);\fP
+
+\fBpng_byte png_get_header_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_header_version (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_eXIf (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fI*exif\fP\fB);\fP
+
+\fBpng_uint_32 png_get_eXIf_1 (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_unit_32 \fP\fI*num_exif\fP\fB, png_bytep \fI*exif\fP\fB);\fP
+
+\fBpng_uint_32 png_get_hIST (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fI*hist\fP\fB);\fP
+
+\fBpng_uint_32 png_get_iCCP (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_bytepp \fP\fIprofile\fP\fB, png_uint_32 \fI*proflen\fP\fB);\fP
+
+\fBpng_uint_32 png_get_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*width\fP\fB, png_uint_32 \fP\fI*height\fP\fB, int \fP\fI*bit_depth\fP\fB, int \fP\fI*color_type\fP\fB, int \fP\fI*interlace_type\fP\fB, int \fP\fI*compression_type\fP\fB, int \fI*filter_type\fP\fB);\fP
+
+\fBpng_uint_32 png_get_image_height (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_image_width (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_int_32 (png_bytep \fIbuf\fP\fB);\fP
+
+\fBpng_byte png_get_interlace_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_io_chunk_type (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_voidp png_get_io_ptr (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_io_state (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_byte png_get_libpng_ver (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBint png_get_palette_max(png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_voidp png_get_mem_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_oFFs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*offset_x\fP\fB, png_uint_32 \fP\fI*offset_y\fP\fB, int \fI*unit_type\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fI*purpose\fP\fB, png_int_32 \fP\fI*X0\fP\fB, png_int_32 \fP\fI*X1\fP\fB, int \fP\fI*type\fP\fB, int \fP\fI*nparams\fP\fB, png_charp \fP\fI*units\fP\fB, png_charpp \fI*params\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pHYs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
+
+\fBfloat png_get_pixel_aspect_ratio (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pHYs_dpi (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP
+
+\fBpng_fixed_point png_get_pixel_aspect_ratio_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_voidp png_get_progressive_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_PLTE (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fI*palette\fP\fB, int \fI*num_palette\fP\fB);\fP
+
+\fBpng_byte png_get_rgb_to_gray_status (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_rowbytes (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_bytepp png_get_rows (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_sBIT (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fI*sig_bit\fP\fB);\fP
+
+\fBvoid png_get_sCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, double* \fP\fIwidth\fP\fB, double* \fIheight\fP\fB);\fP
+
+\fBvoid png_get_sCAL_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_fixed_pointp \fP\fIwidth\fP\fB, png_fixed_pointp \fIheight\fP\fB);\fP
+
+\fBvoid png_get_sCAL_s (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_charpp \fP\fIwidth\fP\fB, png_charpp \fIheight\fP\fB);\fP
+
+\fBpng_bytep png_get_signature (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_sPLT (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fI*splt_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_sRGB (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int \fI*file_srgb_intent\fP\fB);\fP
+
+\fBpng_uint_32 png_get_text (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fI*text_ptr\fP\fB, int \fI*num_text\fP\fB);\fP
+
+\fBpng_uint_32 png_get_tIME (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fI*mod_time\fP\fB);\fP
+
+\fBpng_uint_32 png_get_tRNS (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fI*trans_alpha\fP\fB, int \fP\fI*num_trans\fP\fB, png_color_16p \fI*trans_color\fP\fB);\fP
+
+\fB/* This function is really an inline macro. \fI*/
+
+\fBpng_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP
+
+\fBpng_uint_32 png_get_uint_31 (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIbuf\fP\fB);\fP
+
+\fB/* This function is really an inline macro. \fI*/
+
+\fBpng_uint_32 png_get_uint_32 (png_bytep \fIbuf\fP\fB);\fP
+
+\fBpng_uint_32 png_get_unknown_chunks (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkpp \fIunknowns\fP\fB);\fP
+
+\fBpng_voidp png_get_user_chunk_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_user_height_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_voidp png_get_user_transform_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_user_width_max (png_const_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_valid (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIflag\fP\fB);\fP
+
+\fBfloat png_get_x_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_fixed_point png_get_x_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_x_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_x_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_x_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_x_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBfloat png_get_y_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_fixed_point png_get_y_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_y_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_int_32 png_get_y_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_y_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_get_y_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP
+
+\fBint png_image_begin_read_from_file (png_imagep \fP\fIimage\fP\fB, const char \fI*file_name\fP\fB);\fP
+
+\fBint png_image_begin_read_from_stdio (png_imagep \fP\fIimage\fP\fB, FILE* \fIfile\fP\fB);\fP
+
+\fBint, png_image_begin_read_from_memory (png_imagep \fP\fIimage\fP\fB, png_const_voidp \fP\fImemory\fP\fB, size_t \fIsize\fP\fB);\fP
+
+\fBint png_image_finish_read (png_imagep \fP\fIimage\fP\fB, png_colorp \fP\fIbackground\fP\fB, void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP
+
+\fBvoid png_image_free (png_imagep \fIimage\fP\fB);\fP
+
+\fBint png_image_write_to_file (png_imagep \fP\fIimage\fP\fB, const char \fP\fI*file\fP\fB, int \fP\fIconvert_to_8bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP
+
+\fBint png_image_write_to_memory (png_imagep \fP\fIimage\fP\fB, void \fP\fI*memory\fP\fB, png_alloc_size_t * PNG_RESTRICT \fP\fImemory_bytes\fP\fB, int \fP\fIconvert_to_8_bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, const void \fI*colormap\fP\fB);\fP
+
+\fBint png_image_write_to_stdio (png_imagep \fP\fIimage\fP\fB, FILE \fP\fI*file\fP\fB, int \fP\fIconvert_to_8_bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP
+
+\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, size_t \fIpng_info_struct_size\fP\fB);\fP
+
+\fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP
+
+\fBvoid png_longjmp (png_structp \fP\fIpng_ptr\fP\fB, int \fIval\fP\fB);\fP
+
+\fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fBpng_voidp png_malloc_default (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fBpng_voidp png_malloc_warn (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP
+
+\fBpng_uint_32 png_permit_mng_features (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fImng_features_permitted\fP\fB);\fP
+
+\fBvoid png_process_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, size_t \fIbuffer_size\fP\fB);\fP
+
+\fBsize_t png_process_data_pause (png_structp \fP\fIpng_ptr\fP\fB, int \fIsave\fP\fB);\fP
+
+\fBpng_uint_32 png_process_data_skip (png_structp \fP\fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_progressive_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIold_row\fP\fB, png_bytep \fInew_row\fP\fB);\fP
+
+\fBvoid png_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_read_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
+
+\fBvoid png_read_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_read_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
+
+\fBvoid png_read_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fIdisplay_row\fP\fB);\fP
+
+\fBvoid png_read_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_bytepp \fP\fIdisplay_row\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
+
+\fBvoid png_read_update_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBint png_reset_zstream (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP
+
+\fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP
+
+\fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP
+
+\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
+
+\fBvoid png_set_alpha_mode (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, double \fIoutput_gamma\fP\fB);\fP
+
+\fBvoid png_set_alpha_mode_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, png_fixed_point \fIoutput_gamma\fP\fB);\fP
+
+\fBvoid png_set_background (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, double \fIbackground_gamma\fP\fB);\fP
+
+\fBvoid png_set_background_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, png_uint_32 \fIbackground_gamma\fP\fB);\fP
+
+\fBvoid png_set_benign_errors (png_structp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP
+
+\fBvoid png_set_bgr (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fIbackground\fP\fB);\fP
+
+\fBvoid png_set_check_for_invalid_index (png_structrp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP
+
+\fBvoid png_set_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIwhite_x\fP\fB, double \fP\fIwhite_y\fP\fB, double \fP\fIred_x\fP\fB, double \fP\fIred_y\fP\fB, double \fP\fIgreen_x\fP\fB, double \fP\fIgreen_y\fP\fB, double \fP\fIblue_x\fP\fB, double \fIblue_y\fP\fB);\fP
+
+\fBvoid png_set_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwhite_x\fP\fB, png_uint_32 \fP\fIwhite_y\fP\fB, png_uint_32 \fP\fIred_x\fP\fB, png_uint_32 \fP\fIred_y\fP\fB, png_uint_32 \fP\fIgreen_x\fP\fB, png_uint_32 \fP\fIgreen_y\fP\fB, png_uint_32 \fP\fIblue_x\fP\fB, png_uint_32 \fIblue_y\fP\fB);\fP
+
+\fBvoid png_set_cHRM_XYZ (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIred_X\fP\fB, double \fP\fIred_Y\fP\fB, double \fP\fIred_Z\fP\fB, double \fP\fIgreen_X\fP\fB, double \fP\fIgreen_Y\fP\fB, double \fP\fIgreen_Z\fP\fB, double \fP\fIblue_X\fP\fB, double \fP\fIblue_Y\fP\fB, double \fIblue_Z\fP\fB);\fP
+
+\fBvoid png_set_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fIint_red_X\fP\fB, png_fixed_point \fP\fIint_red_Y\fP\fB, png_fixed_point \fP\fIint_red_Z\fP\fB, png_fixed_point \fP\fIint_green_X\fP\fB, png_fixed_point \fP\fIint_green_Y\fP\fB, png_fixed_point \fP\fIint_green_Z\fP\fB, png_fixed_point \fP\fIint_blue_X\fP\fB, png_fixed_point \fP\fIint_blue_Y\fP\fB, png_fixed_point \fIint_blue_Z\fP\fB);\fP
+
+\fBvoid png_set_chunk_cache_max (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIuser_chunk_cache_max\fP\fB);\fP
+
+\fBvoid png_set_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
+
+\fBvoid png_set_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
+
+\fBvoid png_set_compression_method (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod\fP\fB);\fP
+
+\fBvoid png_set_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
+
+\fBvoid png_set_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
+
+\fBvoid png_set_crc_action (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcrit_action\fP\fB, int \fIancil_action\fP\fB);\fP
+
+\fBvoid png_set_error_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarning_fn\fP\fB);\fP
+
+\fBvoid png_set_expand (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_expand_16 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_expand_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_filler (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
+
+\fBvoid png_set_filter (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImethod\fP\fB, int \fIfilters\fP\fB);\fP
+
+\fBvoid png_set_filter_heuristics (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_doublep \fP\fIfilter_weights\fP\fB, png_doublep \fIfilter_costs\fP\fB);\fP
+
+\fBvoid png_set_filter_heuristics_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_fixed_point_p \fP\fIfilter_weights\fP\fB, png_fixed_point_p \fIfilter_costs\fP\fB);\fP
+
+\fBvoid png_set_flush (png_structp \fP\fIpng_ptr\fP\fB, int \fInrows\fP\fB);\fP
+
+\fBvoid png_set_gamma (png_structp \fP\fIpng_ptr\fP\fB, double \fP\fIscreen_gamma\fP\fB, double \fIdefault_file_gamma\fP\fB);\fP
+
+\fBvoid png_set_gamma_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIscreen_gamma\fP\fB, png_uint_32 \fIdefault_file_gamma\fP\fB);\fP
+
+\fBvoid png_set_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fIfile_gamma\fP\fB);\fP
+
+\fBvoid png_set_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIfile_gamma\fP\fB);\fP
+
+\fBvoid png_set_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_gray_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_eXIf (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fIexif\fP\fB);\fP
+
+\fBvoid png_set_eXIf_1 (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fInum_exif\fP\fB, png_bytep \fIexif\fP\fB);\fP
+
+\fBvoid png_set_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fIhist\fP\fB);\fP
+
+\fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_const_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_const_bytep \fP\fIprofile\fP\fB, png_uint_32 \fIproflen\fP\fB);\fP
+
+\fBint png_set_interlace_handling (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_invalid (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fImask\fP\fB);\fP
+
+\fBvoid png_set_invert_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_invert_mono (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwidth\fP\fB, png_uint_32 \fP\fIheight\fP\fB, int \fP\fIbit_depth\fP\fB, int \fP\fIcolor_type\fP\fB, int \fP\fIinterlace_type\fP\fB, int \fP\fIcompression_type\fP\fB, int \fIfilter_type\fP\fB);\fP
+
+\fBvoid png_set_keep_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIkeep\fP\fB, png_bytep \fP\fIchunk_list\fP\fB, int \fInum_chunks\fP\fB);\fP
+
+\fBjmp_buf* png_set_longjmp_fn (png_structp \fP\fIpng_ptr\fP\fB, png_longjmp_ptr \fP\fIlongjmp_fn\fP\fB, size_t \fIjmp_buf_size\fP\fB);\fP
+
+\fBvoid png_set_chunk_malloc_max (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIuser_chunk_cache_max\fP\fB);\fP
+
+\fBvoid png_set_compression_buffer_size (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP
+
+\fBvoid png_set_mem_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP
+
+\fBvoid png_set_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIoffset_x\fP\fB, png_uint_32 \fP\fIoffset_y\fP\fB, int \fIunit_type\fP\fB);\fP
+
+\fBint png_set_option(png_structrp \fP\fIpng_ptr\fP\fB, int \fP\fIoption\fP\fB, int \fIonoff\fP\fB);\fP
+
+\fBvoid png_set_packing (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_packswap (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_palette_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIpurpose\fP\fB, png_int_32 \fP\fIX0\fP\fB, png_int_32 \fP\fIX1\fP\fB, int \fP\fItype\fP\fB, int \fP\fInparams\fP\fB, png_charp \fP\fIunits\fP\fB, png_charpp \fIparams\fP\fB);\fP
+
+\fBvoid png_set_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIres_x\fP\fB, png_uint_32 \fP\fIres_y\fP\fB, int \fIunit_type\fP\fB);\fP
+
+\fBvoid png_set_progressive_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIprogressive_ptr\fP\fB, png_progressive_info_ptr \fP\fIinfo_fn\fP\fB, png_progressive_row_ptr \fP\fIrow_fn\fP\fB, png_progressive_end_ptr \fIend_fn\fP\fB);\fP
+
+\fBvoid png_set_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fInum_palette\fP\fB);\fP
+
+\fBvoid png_set_quantize (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fP\fInum_palette\fP\fB, int \fP\fImaximum_colors\fP\fB, png_uint_16p \fP\fIhistogram\fP\fB, int \fIfull_quantize\fP\fB);\fP
+
+\fBvoid png_set_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fIread_data_fn\fP\fB);\fP
+
+\fBvoid png_set_read_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_read_status_ptr \fIread_row_fn\fP\fB);\fP
+
+\fBvoid png_set_read_user_chunk_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_chunk_ptr\fP\fB, png_user_chunk_ptr \fIread_user_chunk_fn\fP\fB);\fP
+
+\fBvoid png_set_read_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIread_user_transform_fn\fP\fB);\fP
+
+\fBvoid png_set_rgb_to_gray (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIerror_action\fP\fB, double \fP\fIred\fP\fB, double \fIgreen\fP\fB);\fP
+
+\fBvoid png_set_rgb_to_gray_fixed (png_structp \fP\fIpng_ptr\fP\fB, int error_action png_uint_32 \fP\fIred\fP\fB, png_uint_32 \fIgreen\fP\fB);\fP
+
+\fBvoid png_set_rows (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytepp \fIrow_pointers\fP\fB);\fP
+
+\fBvoid png_set_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fIsig_bit\fP\fB);\fP
+
+\fBvoid png_set_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, double \fP\fIwidth\fP\fB, double \fIheight\fP\fB);\fP
+
+\fBvoid png_set_sCAL_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_fixed_point \fP\fIwidth\fP\fB, png_fixed_point \fIheight\fP\fB);\fP
+
+\fBvoid png_set_sCAL_s (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_charp \fP\fIwidth\fP\fB, png_charp \fIheight\fP\fB);\fP
+
+\fBvoid png_set_scale_16 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_shift (png_structp \fP\fIpng_ptr\fP\fB, png_color_8p \fItrue_bits\fP\fB);\fP
+
+\fBvoid png_set_sig_bytes (png_structp \fP\fIpng_ptr\fP\fB, int \fInum_bytes\fP\fB);\fP
+
+\fBvoid png_set_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fP\fIsplt_ptr\fP\fB, int \fInum_spalettes\fP\fB);\fP
+
+\fBvoid png_set_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
+
+\fBvoid png_set_sRGB_gAMA_and_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP
+
+\fBvoid png_set_strip_16 (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_strip_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_strip_error_numbers (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIstrip_mode\fP\fB);\fP
+
+\fBvoid png_set_swap (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_swap_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_set_text (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fItext_ptr\fP\fB, int \fInum_text\fP\fB);\fP
+
+\fBvoid png_set_text_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP
+
+\fBvoid png_set_text_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP
+
+\fBvoid png_set_text_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP
+
+\fBvoid png_set_text_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP
+
+\fBvoid png_set_text_compression_method (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod\fP\fB);\fP
+
+\fBvoid png_set_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP
+
+\fBvoid png_set_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fItrans_alpha\fP\fB, int \fP\fInum_trans\fP\fB, png_color_16p \fItrans_color\fP\fB);\fP
+
+\fBvoid png_set_tRNS_to_alpha (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBpng_uint_32 png_set_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkp \fP\fIunknowns\fP\fB, int \fP\fInum\fP\fB, int \fIlocation\fP\fB);\fP
+
+\fBvoid png_set_unknown_chunk_location (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIchunk\fP\fB, int \fIlocation\fP\fB);\fP
+
+\fBvoid png_set_user_limits (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIuser_width_max\fP\fB, png_uint_32 \fIuser_height_max\fP\fB);\fP
+
+\fBvoid png_set_user_transform_info (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_transform_ptr\fP\fB, int \fP\fIuser_transform_depth\fP\fB, int \fIuser_transform_channels\fP\fB);\fP
+
+\fBvoid png_set_write_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fP\fIwrite_data_fn\fP\fB, png_flush_ptr \fIoutput_flush_fn\fP\fB);\fP
+
+\fBvoid png_set_write_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_write_status_ptr \fIwrite_row_fn\fP\fB);\fP
+
+\fBvoid png_set_write_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIwrite_user_transform_fn\fP\fB);\fP
+
+\fBint png_sig_cmp (png_bytep \fP\fIsig\fP\fB, size_t \fP\fIstart\fP\fB, size_t \fInum_to_check\fP\fB);\fP
+
+\fBvoid png_start_read_image (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
+
+\fBvoid png_write_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_bytep \fP\fIdata\fP\fB, size_t \fIlength\fP\fB);\fP
+
+\fBvoid png_write_chunk_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, size_t \fIlength\fP\fB);\fP
+
+\fBvoid png_write_chunk_end (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_write_chunk_start (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_uint_32 \fIlength\fP\fB);\fP
+
+\fBvoid png_write_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_write_flush (png_structp \fIpng_ptr\fP\fB);\fP
+
+\fBvoid png_write_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
+
+\fBvoid png_write_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_write_info_before_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
+
+\fBvoid png_write_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP
+
+\fBvoid png_write_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP
+
+\fBvoid png_write_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP
+
+\fBvoid png_write_sig (png_structp \fIpng_ptr\fP\fB);\fP
+
+.SH DESCRIPTION
+The
+.I libpng
+library supports encoding, decoding, and various manipulations of
+the Portable Network Graphics (PNG) format image files.  It uses the
+.IR zlib(3)
+compression library.
+Following is a copy of the libpng-manual.txt file that accompanies libpng.
+
+.SH LIBPNG.TXT
+libpng-manual.txt - A description on how to use and modify libpng
+
+ Copyright (c) 2018-2024 Cosmin Truta
+ Copyright (c) 1998-2018 Glenn Randers-Pehrson
+
+ This document is released under the libpng license.
+ For conditions of distribution and use, see the disclaimer
+ and license in png.h
+
+ Based on:
+
+ libpng version 1.6.36, December 2018, through 1.6.43 - February 2024
+ Updated and distributed by Cosmin Truta
+ Copyright (c) 2018-2024 Cosmin Truta
+
+ libpng versions 0.97, January 1998, through 1.6.35 - July 2018
+ Updated and distributed by Glenn Randers-Pehrson
+ Copyright (c) 1998-2018 Glenn Randers-Pehrson
+
+ libpng 1.0 beta 6 - version 0.96 - May 28, 1997
+ Updated and distributed by Andreas Dilger
+ Copyright (c) 1996, 1997 Andreas Dilger
+
+ libpng 1.0 beta 2 - version 0.88 - January 26, 1996
+ For conditions of distribution and use, see copyright
+ notice in png.h. Copyright (c) 1995, 1996 Guy Eric
+ Schalnat, Group 42, Inc.
+
+ Updated/rewritten per request in the libpng FAQ
+ Copyright (c) 1995, 1996 Frank J. T. Wojcik
+ December 18, 1995 & January 20, 1996
+
+ TABLE OF CONTENTS
+
+    I. Introduction
+   II. Structures
+  III. Reading
+   IV. Writing
+    V. Simplified API
+   VI. Modifying/Customizing libpng
+  VII. MNG support
+ VIII. Changes to Libpng from version 0.88
+   IX. Changes to Libpng from version 1.0.x to 1.2.x
+    X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+   XI. Changes to Libpng from version 1.4.x to 1.5.x
+  XII. Changes to Libpng from version 1.5.x to 1.6.x
+ XIII. Detecting libpng
+  XIV. Source code repository
+   XV. Coding style
+
+.SH I. Introduction
+
+This file describes how to use and modify the PNG reference library
+(known as libpng) for your own use.  In addition to this
+file, example.c is a good starting point for using the library, as
+it is heavily commented and should include everything most people
+will need.  We assume that libpng is already installed; see the
+INSTALL file for instructions on how to configure and install libpng.
+
+For examples of libpng usage, see the files "example.c", "pngtest.c",
+and the files in the "contrib" directory, all of which are included in
+the libpng distribution.
+
+Libpng was written as a companion to the PNG specification, as a way
+of reducing the amount of time and effort it takes to support the PNG
+file format in application programs.
+
+The PNG specification (second edition), November 2003, is available as
+a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
+<https://www.w3.org/TR/2003/REC-PNG-20031110/>.
+The W3C and ISO documents have identical technical content.
+
+The PNG-1.2 specification is available at
+<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
+It is technically equivalent
+to the PNG specification (second edition) but has some additional material.
+
+The PNG-1.0 specification is available as RFC 2083 at
+<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
+W3C Recommendation at <https://www.w3.org/TR/REC-png-961001>.
+
+Some additional chunks are described in the special-purpose public chunks
+documents at <http://www.libpng.org/pub/png/spec/register/>
+
+Other information
+about PNG, and the latest version of libpng, can be found at the PNG home
+page, <http://www.libpng.org/pub/png/>.
+
+Most users will not have to modify the library significantly; advanced
+users may want to modify it more.  All attempts were made to make it as
+complete as possible, while keeping the code easy to understand.
+Currently, this library only supports C.  Support for other languages
+is being considered.
+
+Libpng has been designed to handle multiple sessions at one time,
+to be easily modifiable, to be portable to the vast majority of
+machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
+to use.  The ultimate goal of libpng is to promote the acceptance of
+the PNG file format in whatever way possible.  While there is still
+work to be done (see the TODO file), libpng should cover the
+majority of the needs of its users.
+
+Libpng uses zlib for its compression and decompression of PNG files.
+Further information about zlib, and the latest version of zlib, can
+be found at the zlib home page, <https://zlib.net/>.
+The zlib compression utility is a general purpose utility that is
+useful for more than PNG files, and can be used without libpng.
+See the documentation delivered with zlib for more details.
+You can usually find the source files for the zlib utility wherever you
+find the libpng source files.
+
+Libpng is thread safe, provided the threads are using different
+instances of the structures.  Each thread should have its own
+png_struct and png_info instances, and thus its own image.
+Libpng does not protect itself against two threads using the
+same instance of a structure.
+
+.SH II. Structures
+
+There are two main structures that are important to libpng, png_struct
+and png_info.  Both are internal structures that are no longer exposed
+in the libpng interface (as of libpng 1.5.0).
+
+The png_info structure is designed to provide information about the
+PNG file.  At one time, the fields of png_info were intended to be
+directly accessible to the user.  However, this tended to cause problems
+with applications using dynamically loaded libraries, and as a result
+a set of interface functions for png_info (the png_get_*() and png_set_*()
+functions) was developed, and direct access to the png_info fields was
+deprecated..
+
+The png_struct structure is the object used by the library to decode a
+single image.  As of 1.5.0 this structure is also not exposed.
+
+Almost all libpng APIs require a pointer to a png_struct as the first argument.
+Many (in particular the png_set and png_get APIs) also require a pointer
+to png_info as the second argument.  Some application visible macros
+defined in png.h designed for basic data access (reading and writing
+integers in the PNG format) don't take a png_info pointer, but it's almost
+always safe to assume that a (png_struct*) has to be passed to call an API
+function.
+
+You can have more than one png_info structure associated with an image,
+as illustrated in pngtest.c, one for information valid prior to the
+IDAT chunks and another (called "end_info" below) for things after them.
+
+The png.h header file is an invaluable reference for programming with libpng.
+And while I'm on the topic, make sure you include the libpng header file:
+
+#include <png.h>
+
+and also (as of libpng-1.5.0) the zlib header file, if you need it:
+
+#include <zlib.h>
+
+.SS Types
+
+The png.h header file defines a number of integral types used by the
+APIs.  Most of these are fairly obvious; for example types corresponding
+to integers of particular sizes and types for passing color values.
+
+One exception is how non-integral numbers are handled.  For application
+convenience most APIs that take such numbers have C (double) arguments;
+however, internally PNG, and libpng, use 32 bit signed integers and encode
+the value by multiplying by 100,000.  As of libpng 1.5.0 a convenience
+macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
+which is simply (png_int_32).
+
+All APIs that take (double) arguments also have a matching API that
+takes the corresponding fixed point integer arguments.  The fixed point
+API has the same name as the floating point one with "_fixed" appended.
+The actual range of values permitted in the APIs is frequently less than
+the full range of (png_fixed_point) (\-21474 to +21474).  When APIs require
+a non-negative argument the type is recorded as png_uint_32 above.  Consult
+the header file and the text below for more information.
+
+Special care must be take with sCAL chunk handling because the chunk itself
+uses non-integral values encoded as strings containing decimal floating point
+numbers.  See the comments in the header file.
+
+.SS Configuration
+
+The main header file function declarations are frequently protected by C
+preprocessing directives of the form:
+
+    #ifdef PNG_feature_SUPPORTED
+    declare-function
+    #endif
+    ...
+    #ifdef PNG_feature_SUPPORTED
+    use-function
+    #endif
+
+The library can be built without support for these APIs, although a
+standard build will have all implemented APIs.  Application programs
+should check the feature macros before using an API for maximum
+portability.  From libpng 1.5.0 the feature macros set during the build
+of libpng are recorded in the header file "pnglibconf.h" and this file
+is always included by png.h.
+
+If you don't need to change the library configuration from the default, skip to
+the next section ("Reading").
+
+Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
+of the build project files in the 'projects' directory simply copy
+scripts/pnglibconf.h.prebuilt to pnglibconf.h.  This means that these build
+systems do not permit easy auto-configuration of the library - they only
+support the default configuration.
+
+The easiest way to make minor changes to the libpng configuration when
+auto-configuration is supported is to add definitions to the command line
+using (typically) CPPFLAGS.  For example:
+
+CPPFLAGS=\-DPNG_NO_FLOATING_ARITHMETIC
+
+will change the internal libpng math implementation for gamma correction and
+other arithmetic calculations to fixed point, avoiding the need for fast
+floating point support.  The result can be seen in the generated pnglibconf.h -
+make sure it contains the changed feature macro setting.
+
+If you need to make more extensive configuration changes - more than one or two
+feature macro settings - you can either add \-DPNG_USER_CONFIG to the build
+command line and put a list of feature macro settings in pngusr.h or you can set
+DFA_XTRA (a makefile variable) to a file containing the same information in the
+form of 'option' settings.
+
+A. Changing pnglibconf.h
+
+A variety of methods exist to build libpng.  Not all of these support
+reconfiguration of pnglibconf.h.  To reconfigure pnglibconf.h it must either be
+rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
+
+Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to
+pnglibconf.h and changing the lines defining the supported features, paying
+very close attention to the 'option' information in scripts/pnglibconf.dfa
+that describes those features and their requirements.  This is easy to get
+wrong.
+
+B. Configuration using DFA_XTRA
+
+Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
+variant such as 'nawk' or 'gawk', is available.  The configure build will
+automatically find an appropriate awk and build pnglibconf.h.
+The scripts/pnglibconf.mak file contains a set of make rules for doing the
+same thing if configure is not used, and many of the makefiles in the scripts
+directory use this approach.
+
+When rebuilding simply write a new file containing changed options and set
+DFA_XTRA to the name of this file.  This causes the build to append the new file
+to the end of scripts/pnglibconf.dfa.  The pngusr.dfa file should contain lines
+of the following forms:
+
+everything = off
+
+This turns all optional features off.  Include it at the start of pngusr.dfa to
+make it easier to build a minimal configuration.  You will need to turn at least
+some features on afterward to enable either reading or writing code, or both.
+
+option feature on
+option feature off
+
+Enable or disable a single feature.  This will automatically enable other
+features required by a feature that is turned on or disable other features that
+require a feature which is turned off.  Conflicting settings will cause an error
+message to be emitted by awk.
+
+setting feature default value
+
+Changes the default value of setting 'feature' to 'value'.  There are a small
+number of settings listed at the top of pnglibconf.h, they are documented in the
+source code.  Most of these values have performance implications for the library
+but most of them have no visible effect on the API.  Some can also be overridden
+from the API.
+
+This method of building a customized pnglibconf.h is illustrated in
+contrib/pngminim/*.  See the "$(PNGCONF):" target in the makefile and
+pngusr.dfa in these directories.
+
+C. Configuration using PNG_USER_CONFIG
+
+If \-DPNG_USER_CONFIG is added to the CPPFLAGS when pnglibconf.h is built,
+the file pngusr.h will automatically be included before the options in
+scripts/pnglibconf.dfa are processed.  Your pngusr.h file should contain only
+macro definitions turning features on or off or setting settings.
+
+Apart from the global setting "everything = off" all the options listed above
+can be set using macros in pngusr.h:
+
+#define PNG_feature_SUPPORTED
+
+is equivalent to:
+
+option feature on
+
+#define PNG_NO_feature
+
+is equivalent to:
+
+option feature off
+
+#define PNG_feature value
+
+is equivalent to:
+
+setting feature default value
+
+Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
+pngusr file you supply override the contents of scripts/pnglibconf.dfa
+
+If confusing or incomprehensible behavior results it is possible to
+examine the intermediate file pnglibconf.dfn to find the full set of
+dependency information for each setting and option.  Simply locate the
+feature in the file and read the C comments that precede it.
+
+This method is also illustrated in the contrib/pngminim/* makefiles and
+pngusr.h.
+
+.SH III. Reading
+
+We'll now walk you through the possible functions to call when reading
+in a PNG file sequentially, briefly explaining the syntax and purpose
+of each one.  See example.c and png.h for more detail.  While
+progressive reading is covered in the next section, you will still
+need some of the functions discussed in this section to read a PNG
+file.
+
+.SS Setup
+
+You will want to do the I/O initialization(*) before you get into libpng,
+so if it doesn't work, you don't have much to undo.  Of course, you
+will also want to insure that you are, in fact, dealing with a PNG
+file.  Libpng provides a simple check to see if a file is a PNG file.
+To use it, pass in the first 1 to 8 bytes of the file to the function
+png_sig_cmp(), and it will return 0 (false) if the bytes match the
+corresponding bytes of the PNG signature, or nonzero (true) otherwise.
+Of course, the more bytes you pass in, the greater the accuracy of the
+prediction.
+
+If you are intending to keep the file pointer open for use in libpng,
+you must ensure you don't read more than 8 bytes from the beginning
+of the file, and you also have to make a call to png_set_sig_bytes()
+with the number of bytes you read from the beginning.  Libpng will
+then only check the bytes (if any) that your program didn't read.
+
+(*): If you are not using the standard I/O functions, you will need
+to replace them with custom functions.  See the discussion under
+Customizing libpng.
+
+    FILE *fp = fopen(file_name, "rb");
+    if (!fp)
+    {
+       return ERROR;
+    }
+
+    if (fread(header, 1, number, fp) != number)
+    {
+       return ERROR;
+    }
+
+    is_png = (png_sig_cmp(header, 0, number) == 0);
+    if (!is_png)
+    {
+       return NOT_PNG;
+    }
+
+Next, png_struct and png_info need to be allocated and initialized.  In
+order to ensure that the size of these structures is correct even with a
+dynamically linked libpng, there are functions to initialize and
+allocate the structures.  We also pass the library version, optional
+pointers to error handling functions, and a pointer to a data struct for
+use by the error functions, if necessary (the pointer and functions can
+be NULL if the default error handlers are to be used).  See the section
+on Changes to Libpng below regarding the old initialization functions.
+The structure allocation functions quietly return NULL if they fail to
+create the structure, so your application should check for that.
+
+    png_structp png_ptr = png_create_read_struct
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+       return ERROR;
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+    {
+       png_destroy_read_struct(&png_ptr, NULL, NULL);
+       return ERROR;
+    }
+
+If you want to use your own memory allocation routines,
+use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
+png_create_read_struct_2() instead of png_create_read_struct():
+
+    png_structp png_ptr = png_create_read_struct_2
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn, (png_voidp)
+        user_mem_ptr, user_malloc_fn, user_free_fn);
+
+The error handling routines passed to png_create_read_struct()
+and the memory alloc/free routines passed to png_create_struct_2()
+are only necessary if you are not using the libpng supplied error
+handling and memory alloc/free functions.
+
+When libpng encounters an error, it expects to longjmp back
+to your routine.  Therefore, you will need to call setjmp and pass
+your png_jmpbuf(png_ptr).  If you read the file from different
+routines, you will need to update the longjmp buffer every time you enter
+a new routine that will call a png_*() function.
+
+See your documentation of setjmp/longjmp for your compiler for more
+information on setjmp/longjmp.  See the discussion on libpng error
+handling in the Customizing Libpng section below for more information
+on the libpng error handling.  If an error occurs, and libpng longjmp's
+back to your setjmp, you will want to call png_destroy_read_struct() to
+free any memory.
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
+       fclose(fp);
+       return ERROR;
+    }
+
+Pass NULL instead of &end_info if you didn't create an end_info
+structure.
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Now you need to set up the input code.  The default for libpng is to
+use the C function fread().  If you use this, you will need to pass a
+valid FILE * in the function png_init_io().  Be sure that the file is
+opened in binary mode.  If you wish to handle reading data in another
+way, you need not call the png_init_io() function, but you must then
+implement the libpng I/O methods discussed in the Customizing Libpng
+section below.
+
+    png_init_io(png_ptr, fp);
+
+If you had previously opened the file and read any of the signature from
+the beginning in order to see if this was a PNG file, you need to let
+libpng know that there are some bytes missing from the start of the file.
+
+    png_set_sig_bytes(png_ptr, number);
+
+You can change the zlib compression buffer size to be used while
+reading compressed data with
+
+    png_set_compression_buffer_size(png_ptr, buffer_size);
+
+where the default size is 8192 bytes.  Note that the buffer size
+is changed immediately and the buffer is reallocated immediately,
+instead of setting a flag to be acted upon later.
+
+If you want CRC errors to be handled in a different manner than
+the default, use
+
+    png_set_crc_action(png_ptr, crit_action, ancil_action);
+
+The values for png_set_crc_action() say how libpng is to handle CRC errors in
+ancillary and critical chunks, and whether to use the data contained
+therein. Starting with libpng-1.6.26, this also governs how an ADLER32 error
+is handled while reading the IDAT chunk. Note that it is impossible to
+"discard" data in a critical chunk.
+
+Choices for (int) crit_action are
+   PNG_CRC_DEFAULT      0  error/quit
+   PNG_CRC_ERROR_QUIT   1  error/quit
+   PNG_CRC_WARN_USE     3  warn/use data
+   PNG_CRC_QUIET_USE    4  quiet/use data
+   PNG_CRC_NO_CHANGE    5  use the current value
+
+Choices for (int) ancil_action are
+   PNG_CRC_DEFAULT      0  error/quit
+   PNG_CRC_ERROR_QUIT   1  error/quit
+   PNG_CRC_WARN_DISCARD 2  warn/discard data
+   PNG_CRC_WARN_USE     3  warn/use data
+   PNG_CRC_QUIET_USE    4  quiet/use data
+   PNG_CRC_NO_CHANGE    5  use the current value
+
+When the setting for crit_action is PNG_CRC_QUIET_USE, the CRC and ADLER32
+checksums are not only ignored, but they are not evaluated.
+
+.SS Setting up callback code
+
+You can set up a callback function to handle any unknown chunks in the
+input stream. You must supply the function
+
+    read_chunk_callback(png_structp png_ptr,
+         png_unknown_chunkp chunk)
+    {
+       /* The unknown chunk structure contains your
+          chunk data, along with similar data for any other
+          unknown chunks: */
+
+           png_byte name[5];
+           png_byte *data;
+           size_t size;
+
+       /* Note that libpng has already taken care of
+          the CRC handling */
+
+       /* put your code here.  Search for your chunk in the
+          unknown chunk structure, process it, and return one
+          of the following: */
+
+       return \-n; /* chunk had an error */
+       return 0; /* did not recognize */
+       return n; /* success */
+    }
+
+(You can give your function another name that you like instead of
+"read_chunk_callback")
+
+To inform libpng about your function, use
+
+    png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
+        read_chunk_callback);
+
+This names not only the callback function, but also a user pointer that
+you can retrieve with
+
+    png_get_user_chunk_ptr(png_ptr);
+
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks which the callback does not handle will be saved when read.  You can
+cause them to be discarded by returning '1' ("handled") instead of '0'.  This
+behavior will change in libpng 1.7 and the default handling set by the
+png_set_keep_unknown_chunks() function, described below, will be used when the
+callback returns 0.  If you want the existing behavior you should set the global
+default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
+versions of libpng and with 1.7.  Libpng 1.6 issues a warning if you keep the
+default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.
+
+At this point, you can set up a callback function that will be
+called after each row has been read, which you can use to control
+a progress meter or the like.  It's demonstrated in pngtest.c.
+You must supply a function
+
+    void read_row_callback(png_structp png_ptr,
+       png_uint_32 row, int pass)
+    {
+       /* put your code here */
+    }
+
+(You can give it another name that you like instead of "read_row_callback")
+
+To inform libpng about your function, use
+
+    png_set_read_status_fn(png_ptr, read_row_callback);
+
+When this function is called the row has already been completely processed and
+the 'row' and 'pass' refer to the next row to be handled.  For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0.  For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes.  Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass\-1'; if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+.SS Unknown-chunk handling
+
+Now you get to set the way the library processes unknown chunks in the
+input PNG stream. Both known and unknown chunks will be read.  Normal
+behavior is that known chunks will be parsed into information in
+various info_ptr members while unknown chunks will be discarded. This
+behavior can be wasteful if your application will never use some known
+chunk types. To change this, you can call:
+
+    png_set_keep_unknown_chunks(png_ptr, keep,
+        chunk_list, num_chunks);
+
+    keep       - 0: default unknown chunk handling
+                 1: ignore; do not keep
+                 2: keep only if safe-to-copy
+                 3: keep even if unsafe-to-copy
+
+               You can use these definitions:
+                 PNG_HANDLE_CHUNK_AS_DEFAULT   0
+                 PNG_HANDLE_CHUNK_NEVER        1
+                 PNG_HANDLE_CHUNK_IF_SAFE      2
+                 PNG_HANDLE_CHUNK_ALWAYS       3
+
+    chunk_list - list of chunks affected (a byte string,
+                 five bytes per chunk, NULL or '\0' if
+                 num_chunks is positive; ignored if
+                 numchunks <= 0).
+
+    num_chunks - number of chunks affected; if 0, all
+                 unknown chunks are affected.  If positive,
+                 only the chunks in the list are affected,
+                 and if negative all unknown chunks and
+                 all known chunks except for the IHDR,
+                 PLTE, tRNS, IDAT, and IEND chunks are
+                 affected.
+
+Unknown chunks declared in this way will be saved as raw data onto a
+list of png_unknown_chunk structures.  If a chunk that is normally
+known to libpng is named in the list, it will be handled as unknown,
+according to the "keep" directive.  If a chunk is named in successive
+instances of png_set_keep_unknown_chunks(), the final instance will
+take precedence.  The IHDR and IEND chunks should not be named in
+chunk_list; if they are, libpng will process them normally anyway.
+If you know that your application will never make use of some particular
+chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below.
+
+Here is an example of the usage of png_set_keep_unknown_chunks(),
+where the private "vpAg" chunk will later be processed by a user chunk
+callback function:
+
+    png_byte vpAg[5]={118, 112,  65, 103, (png_byte) '\0'};
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      png_byte unused_chunks[]=
+      {
+        104,  73,  83,  84, (png_byte) '\0',   /* hIST */
+        105,  84,  88, 116, (png_byte) '\0',   /* iTXt */
+        112,  67,  65,  76, (png_byte) '\0',   /* pCAL */
+        115,  67,  65,  76, (png_byte) '\0',   /* sCAL */
+        115,  80,  76,  84, (png_byte) '\0',   /* sPLT */
+        116,  73,  77,  69, (png_byte) '\0',   /* tIME */
+      };
+    #endif
+
+    ...
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      /* ignore all unknown chunks
+       * (use global setting "2" for libpng16 and earlier):
+       */
+      png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);
+
+      /* except for vpAg: */
+      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
+
+      /* also ignore unused known chunks: */
+      png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
+         (int)(sizeof unused_chunks)/5);
+    #endif
+
+.SS User limits
+
+The PNG specification allows the width and height of an image to be as
+large as 2^(31\-1 (0x7fffffff), or about 2.147 billion rows and columns.
+For safety, libpng imposes a default limit of 1 million rows and columns.
+Larger images will be rejected immediately with a png_error() call. If
+you wish to change these limits, you can use
+
+   png_set_user_limits(png_ptr, width_max, height_max);
+
+to set your own limits (libpng may reject some very wide images
+anyway because of potential buffer overflow conditions).
+
+You should put this statement after you create the PNG structure and
+before calling png_read_info(), png_read_png(), or png_process_data().
+
+When writing a PNG datastream, put this statement before calling
+png_write_info() or png_write_png().
+
+If you need to retrieve the limits that are being applied, use
+
+   width_max = png_get_user_width_max(png_ptr);
+   height_max = png_get_user_height_max(png_ptr);
+
+The PNG specification sets no limit on the number of ancillary chunks
+allowed in a PNG datastream.  By default, libpng imposes a limit of
+a total of 1000 sPLT, tEXt, iTXt, zTXt, and unknown chunks to be stored.
+If you have set up both info_ptr and end_info_ptr, the limit applies
+separately to each.  You can change the limit on the total number of such
+chunks that will be stored, with
+
+   png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
+
+where 0x7fffffffL means unlimited.  You can retrieve this limit with
+
+   chunk_cache_max = png_get_chunk_cache_max(png_ptr);
+
+Libpng imposes a limit of 8 Megabytes (8,000,000 bytes) on the amount of
+memory that any chunk other than IDAT can occupy, originally or when
+decompressed (prior to libpng-1.6.32 the limit was only applied to compressed
+chunks after decompression). You can change this limit with
+
+   png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
+
+and you can retrieve the limit with
+
+   chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
+
+Any chunks that would cause either of these limits to be exceeded will
+be ignored.
+
+.SS Information about your system
+
+If you intend to display the PNG or to incorporate it in other image data you
+need to tell libpng information about your display or drawing surface so that
+libpng can convert the values in the image to match the display.
+
+From libpng-1.5.4 this information can be set before reading the PNG file
+header.  In earlier versions png_set_gamma() existed but behaved incorrectly if
+called before the PNG file header had been read and png_set_alpha_mode() did not
+exist.
+
+If you need to support versions prior to libpng-1.5.4 test the version number
+as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures
+described in the appropriate manual page.
+
+You give libpng the encoding expected by your system expressed as a 'gamma'
+value.  You can also specify a default encoding for the PNG file in
+case the required information is missing from the file.  By default libpng
+assumes that the PNG data matches your system, to keep this default call:
+
+   png_set_gamma(png_ptr, screen_gamma, output_gamma);
+
+or you can use the fixed point equivalent:
+
+   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma,
+      PNG_FP_1*output_gamma);
+
+If you don't know the gamma for your system it is probably 2.2 - a good
+approximation to the IEC standard for display systems (sRGB).  If images are
+too contrasty or washed out you got the value wrong - check your system
+documentation!
+
+Many systems permit the system gamma to be changed via a lookup table in the
+display driver, a few systems, including older Macs, change the response by
+default.  As of 1.5.4 three special values are available to handle common
+situations:
+
+   PNG_DEFAULT_sRGB: Indicates that the system conforms to the
+                     IEC 61966-2-1 standard.  This matches almost
+                     all systems.
+   PNG_GAMMA_MAC_18: Indicates that the system is an older
+                     (pre Mac OS 10.6) Apple Macintosh system with
+                     the default settings.
+   PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates
+                     that the system expects data with no gamma
+                     encoding.
+
+You would use the linear (unencoded) value if you need to process the pixel
+values further because this avoids the need to decode and re-encode each
+component value whenever arithmetic is performed.  A lot of graphics software
+uses linear values for this reason, often with higher precision component values
+to preserve overall accuracy.
+
+
+The output_gamma value expresses how to decode the output values, not how
+they are encoded.  The values used correspond to the normal numbers used to
+describe the overall gamma of a computer display system; for example 2.2 for
+an sRGB conformant system.  The values are scaled by 100000 in the _fixed
+version of the API (so 220000 for sRGB.)
+
+The inverse of the value is always used to provide a default for the PNG file
+encoding if it has no gAMA chunk and if png_set_gamma() has not been called
+to override the PNG gamma information.
+
+When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
+opaque pixels however pixels with lower alpha values are not encoded,
+regardless of the output gamma setting.
+
+When the standard Porter Duff handling is requested with mode 1 the output
+encoding is set to be linear and the output_gamma value is only relevant
+as a default for input data that has no gamma information.  The linear output
+encoding will be overridden if png_set_gamma() is called - the results may be
+highly unexpected!
+
+The following numbers are derived from the sRGB standard and the research
+behind it.  sRGB is defined to be approximated by a PNG gAMA chunk value of
+0.45455 (1/2.2) for PNG.  The value implicitly includes any viewing
+correction required to take account of any differences in the color
+environment of the original scene and the intended display environment; the
+value expresses how to *decode* the image for display, not how the original
+data was *encoded*.
+
+sRGB provides a peg for the PNG standard by defining a viewing environment.
+sRGB itself, and earlier TV standards, actually use a more complex transform
+(a linear portion then a gamma 2.4 power law) than PNG can express.  (PNG is
+limited to simple power laws.)  By saying that an image for direct display on
+an sRGB conformant system should be stored with a gAMA chunk value of 45455
+(11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
+makes it possible to derive values for other display systems and
+environments.
+
+The Mac value is deduced from the sRGB based on an assumption that the actual
+extra viewing correction used in early Mac display systems was implemented as
+a power 1.45 lookup table.
+
+Any system where a programmable lookup table is used or where the behavior of
+the final display device characteristics can be changed requires system
+specific code to obtain the current characteristic.  However this can be
+difficult and most PNG gamma correction only requires an approximate value.
+
+By default, if png_set_alpha_mode() is not called, libpng assumes that all
+values are unencoded, linear, values and that the output device also has a
+linear characteristic.  This is only very rarely correct - it is invariably
+better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
+default if you don't know what the right answer is!
+
+The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
+10.6) which used a correction table to implement a somewhat lower gamma on an
+otherwise sRGB system.
+
+Both these values are reserved (not simple gamma values) in order to allow
+more precise correction internally in the future.
+
+NOTE: the values can be passed to either the fixed or floating
+point APIs, but the floating point API will also accept floating point
+values.
+
+The second thing you may need to tell libpng about is how your system handles
+alpha channel information.  Some, but not all, PNG files contain an alpha
+channel.  To display these files correctly you need to compose the data onto a
+suitable background, as described in the PNG specification.
+
+Libpng only supports composing onto a single color (using png_set_background;
+see below).  Otherwise you must do the composition yourself and, in this case,
+you may need to call png_set_alpha_mode:
+
+   #if PNG_LIBPNG_VER >= 10504
+      png_set_alpha_mode(png_ptr, mode, screen_gamma);
+   #else
+      png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma);
+   #endif
+
+The screen_gamma value is the same as the argument to png_set_gamma; however,
+how it affects the output depends on the mode.  png_set_alpha_mode() sets the
+file gamma default to 1/screen_gamma, so normally you don't need to call
+png_set_gamma.  If you need different defaults call png_set_gamma() before
+png_set_alpha_mode() - if you call it after it will override the settings made
+by png_set_alpha_mode().
+
+The mode is as follows:
+
+    PNG_ALPHA_PNG: The data is encoded according to the PNG
+specification.  Red, green and blue, or gray, components are
+gamma encoded color values and are not premultiplied by the
+alpha value.  The alpha value is a linear measure of the
+contribution of the pixel to the corresponding final output pixel.
+
+You should normally use this format if you intend to perform
+color correction on the color values; most, maybe all, color
+correction software has no handling for the alpha channel and,
+anyway, the math to handle pre-multiplied component values is
+unnecessarily complex.
+
+Before you do any arithmetic on the component values you need
+to remove the gamma encoding and multiply out the alpha
+channel.  See the PNG specification for more detail.  It is
+important to note that when an image with an alpha channel is
+scaled, linear encoded, pre-multiplied component values must
+be used!
+
+The remaining modes assume you don't need to do any further color correction or
+that if you do, your color correction software knows all about alpha (it
+probably doesn't!).  They 'associate' the alpha with the color information by
+storing color channel values that have been scaled by the alpha.  The
+advantage is that the color channels can be resampled (the image can be
+scaled) in this form.  The disadvantage is that normal practice is to store
+linear, not (gamma) encoded, values and this requires 16-bit channels for
+still images rather than the 8-bit channels that are just about sufficient if
+gamma encoding is used.  In addition all non-transparent pixel values,
+including completely opaque ones, must be gamma encoded to produce the final
+image.  These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+described below (the latter being the two common names for associated alpha
+color channels). Note that PNG files always contain non-associated color
+channels; png_set_alpha_mode() with one of the modes causes the decoder to
+convert the pixels to an associated form before returning them to your
+application.
+
+Since it is not necessary to perform arithmetic on opaque color values so
+long as they are not to be resampled and are in the final color space it is
+possible to optimize the handling of alpha by storing the opaque pixels in
+the PNG format (adjusted for the output color space) while storing partially
+opaque pixels in the standard, linear, format.  The accuracy required for
+standard alpha composition is relatively low, because the pixels are
+isolated, therefore typically the accuracy loss in storing 8-bit linear
+values is acceptable.  (This is not true if the alpha channel is used to
+simulate transparency over large areas - use 16 bits or the PNG mode in
+this case!)  This is the 'OPTIMIZED' mode.  For this mode a pixel is
+treated as opaque only if the alpha value is equal to the maximum value.
+
+    PNG_ALPHA_STANDARD:  The data libpng produces is encoded in the
+standard way assumed by most correctly written graphics software.
+The gamma encoding will be removed by libpng and the
+linear component values will be pre-multiplied by the
+alpha channel.
+
+With this format the final image must be re-encoded to
+match the display gamma before the image is displayed.
+If your system doesn't do that, yet still seems to
+perform arithmetic on the pixels without decoding them,
+it is broken - check out the modes below.
+
+With PNG_ALPHA_STANDARD libpng always produces linear
+component values, whatever screen_gamma you supply.  The
+screen_gamma value is, however, used as a default for
+the file gamma if the PNG file has no gamma information.
+
+If you call png_set_gamma() after png_set_alpha_mode() you
+will override the linear encoding.  Instead the
+pre-multiplied pixel values will be gamma encoded but
+the alpha channel will still be linear.  This may
+actually match the requirements of some broken software,
+but it is unlikely.
+
+While linear 8-bit data is often used it has
+insufficient precision for any image with a reasonable
+dynamic range.  To avoid problems, and if your software
+supports it, use png_set_expand_16() to force all
+components to 16 bits.
+
+    PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD
+except that completely opaque pixels are gamma encoded according to
+the screen_gamma value.  Pixels with alpha less than 1.0
+will still have linear components.
+
+Use this format if you have control over your
+compositing software and so don't do other arithmetic
+(such as scaling) on the data you get from libpng.  Your
+compositing software can simply copy opaque pixels to
+the output but still has linear values for the
+non-opaque pixels.
+
+In normal compositing, where the alpha channel encodes
+partial pixel coverage (as opposed to broad area
+translucency), the inaccuracies of the 8-bit
+representation of non-opaque pixels are irrelevant.
+
+You can also try this format if your software is broken;
+it might look better.
+
+    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD; however, all component
+values, including the alpha channel are gamma encoded.  This is
+broken because, in practice, no implementation that uses this choice
+correctly undoes the encoding before handling alpha composition.  Use this
+choice only if other serious errors in the software or hardware you use
+mandate it.  In most cases of broken software or hardware the bug in the
+final display manifests as a subtle halo around composited parts of the
+image.  You may not even perceive this as a halo; the composited part of
+the image may simply appear separate from the background, as though it had
+been cut out of paper and pasted on afterward.
+
+If you don't have to deal with bugs in software or hardware, or if you can fix
+them, there are three recommended ways of using png_set_alpha_mode():
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
+       screen_gamma);
+
+You can do color correction on the result (libpng does not currently
+support color correction internally).  When you handle the alpha channel
+you need to undo the gamma encoding and multiply out the alpha.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
+       screen_gamma);
+   png_set_expand_16(png_ptr);
+
+If you are using the high level interface, don't call png_set_expand_16();
+instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
+
+With this mode you can't do color correction, but you can do arithmetic,
+including composition and scaling, on the data without further processing.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
+       screen_gamma);
+
+You can avoid the expansion to 16-bit components with this mode, but you
+lose the ability to scale the image or perform other linear arithmetic.
+All you can do is compose the result onto a matching output.  Since this
+mode is libpng-specific you also need to write your own composition
+software.
+
+The following are examples of calls to png_set_alpha_mode to achieve the
+required overall gamma correction and, where necessary, alpha
+premultiplication.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+
+Choices for the alpha_mode are
+
+    PNG_ALPHA_PNG           0 /* according to the PNG standard */
+    PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
+    PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
+    PNG_ALPHA_PREMULTIPLIED 1 /* as above */
+    PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
+    PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
+
+PNG_ALPHA_PNG is the default libpng handling of the alpha channel. It is not
+pre-multiplied into the color components. In addition the call states
+that the output is for a sRGB system and causes all PNG files without gAMA
+chunks to be assumed to be encoded using sRGB.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+In this case the output is assumed to be something like an sRGB conformant
+display preceded by a power-law lookup table of power 1.45.  This is how
+early Mac systems behaved.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+
+This is the classic Jim Blinn approach and will work in academic
+environments where everything is done by the book.  It has the shortcoming
+of assuming that input PNG data with no gamma information is linear - this
+is unlikely to be correct unless the PNG files were generated locally.
+Most of the time the output precision will be so low as to show
+significant banding in dark areas of the image.
+
+    png_set_expand_16(pp);
+    png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+
+This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
+are assumed to have the sRGB encoding if not marked with a gamma value and
+the output is always 16 bits per component.  This permits accurate scaling
+and processing of the data.  If you know that your input PNG files were
+generated locally you might need to replace PNG_DEFAULT_sRGB with the
+correct value for your system.
+
+    png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+
+If you just need to composite the PNG image onto an existing background
+and if you control the code that does this you can use the optimization
+setting.  In this case you just copy completely opaque pixels to the
+output.  For pixels that are not completely transparent (you just skip
+those) you do the composition math using png_composite or png_composite_16
+below then encode the resultant 8-bit or 16-bit values to match the output
+encoding.
+
+    Other cases
+
+If neither the PNG nor the standard linear encoding work for you because
+of the software or hardware you use then you have a big problem.  The PNG
+case will probably result in halos around the image.  The linear encoding
+will probably result in a washed out, too bright, image (it's actually too
+contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
+substantially reduce the halos.  Alternatively try:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+
+This option will also reduce the halos, but there will be slight dark
+halos round the opaque parts of the image where the background is light.
+In the OPTIMIZED mode the halos will be light halos where the background
+is dark.  Take your pick - the halos are unavoidable unless you can get
+your hardware/software fixed!  (The OPTIMIZED approach is slightly
+faster.)
+
+When the default gamma of PNG files doesn't match the output gamma.
+If you have PNG files with no gamma information png_set_alpha_mode allows
+you to provide a default gamma, but it also sets the output gamma to the
+matching value.  If you know your PNG files have a gamma that doesn't
+match the output you can take advantage of the fact that
+png_set_alpha_mode always sets the output gamma but only sets the PNG
+default if it is not already set:
+
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+    png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+The first call sets both the default and the output gamma values, the
+second call overrides the output gamma without changing the default.  This
+is easier than achieving the same effect with png_set_gamma.  You must use
+PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+fire if more than one call to png_set_alpha_mode and png_set_background is
+made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+are ignored.
+
+If you don't need, or can't handle, the alpha channel you can call
+png_set_background() to remove it by compositing against a fixed color.  Don't
+call png_set_strip_alpha() to do this - it will leave spurious pixel values in
+transparent parts of this image.
+
+   png_set_background(png_ptr, &background_color,
+       PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
+
+The background_color is an RGB or grayscale value according to the data format
+libpng will produce for you.  Because you don't yet know the format of the PNG
+file, if you call png_set_background at this point you must arrange for the
+format produced by libpng to always have 8-bit or 16-bit components and then
+store the color as an 8-bit or 16-bit color as appropriate.  The color contains
+separate gray and RGB component values, so you can let libpng produce gray or
+RGB output according to the input format, but low bit depth grayscale images
+must always be converted to at least 8-bit format.  (Even though low bit depth
+grayscale images can't have an alpha channel they can have a transparent
+color!)
+
+You set the transforms you need later, either as flags to the high level
+interface or libpng API calls for the low level interface.  For reference the
+settings and API calls required are:
+
+8-bit values:
+   PNG_TRANSFORM_SCALE_16 | PNG_EXPAND
+   png_set_expand(png_ptr); png_set_scale_16(png_ptr);
+
+   If you must get exactly the same inaccurate results
+   produced by default in versions prior to libpng-1.5.4,
+   use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr)
+   instead.
+
+16-bit values:
+   PNG_TRANSFORM_EXPAND_16
+   png_set_expand_16(png_ptr);
+
+In either case palette image data will be expanded to RGB.  If you just want
+color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
+to the list.
+
+Calling png_set_background before the PNG file header is read will not work
+prior to libpng-1.5.4.  Because the failure may result in unexpected warnings or
+errors it is therefore much safer to call png_set_background after the head has
+been read.  Unfortunately this means that prior to libpng-1.5.4 it cannot be
+used with the high level interface.
+
+.SS The high-level read interface
+
+At this point there are two ways to proceed; through the high-level
+read interface, or through a sequence of low-level read operations.
+You can use the high-level interface if (a) you are willing to read
+the entire image into memory, and (b) the input transformations
+you want to do are limited to the following set:
+
+    PNG_TRANSFORM_IDENTITY      No transformation
+    PNG_TRANSFORM_SCALE_16      Strip 16-bit samples to
+                                8-bit accurately
+    PNG_TRANSFORM_STRIP_16      Chop 16-bit samples to
+                                8-bit less accurately
+    PNG_TRANSFORM_STRIP_ALPHA   Discard the alpha channel
+    PNG_TRANSFORM_PACKING       Expand 1, 2 and 4-bit
+                                samples to bytes
+    PNG_TRANSFORM_PACKSWAP      Change order of packed
+                                pixels to LSB first
+    PNG_TRANSFORM_EXPAND        Perform set_expand()
+    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
+    PNG_TRANSFORM_SHIFT         Normalize pixels to the
+                                sBIT depth
+    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
+                                to BGRA
+    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
+                                to AG
+    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
+                                to transparency
+    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
+    PNG_TRANSFORM_GRAY_TO_RGB   Expand grayscale samples
+                                to RGB (or GA to RGBA)
+    PNG_TRANSFORM_EXPAND_16     Expand samples to 16 bits
+
+(This excludes setting a background color, doing gamma transformation,
+quantizing, and setting filler.)  If this is the case, simply do this:
+
+    png_read_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some
+set of transformation flags.  This call is equivalent to png_read_info(),
+followed the set of transformations indicated by the transform mask,
+then png_read_image(), and finally png_read_end().
+
+(The final parameter of this call is not yet used.  Someday it might point
+to transformation parameters required by some future input transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_read_png().
+
+After you have called png_read_png(), you can retrieve the image data
+with
+
+   row_pointers = png_get_rows(png_ptr, info_ptr);
+
+where row_pointers is an array of pointers to the pixel data for each row:
+
+   png_bytep row_pointers[height];
+
+If you know your image size and pixel size ahead of time, you can allocate
+row_pointers prior to calling png_read_png() with
+
+   if (height > PNG_UINT_32_MAX / (sizeof (png_bytep)))
+      png_error(png_ptr,
+          "Image is too tall to process in memory");
+
+   if (width > PNG_UINT_32_MAX / pixel_size)
+      png_error(png_ptr,
+          "Image is too wide to process in memory");
+
+   row_pointers = png_malloc(png_ptr,
+       height*(sizeof (png_bytep)));
+
+   for (int i = 0; i < height, i++)
+      row_pointers[i] = NULL;  /* security precaution */
+
+   for (int i = 0; i < height, i++)
+      row_pointers[i] = png_malloc(png_ptr,
+          width*pixel_size);
+
+   png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+Alternatively you could allocate your image in one big block and define
+row_pointers[i] to point into the proper places in your block, but first
+be sure that your platform is able to allocate such a large buffer:
+
+   /* Guard against integer overflow */
+   if (height > PNG_SIZE_MAX/(width*pixel_size))
+      png_error(png_ptr, "image_data buffer would be too large");
+
+   png_bytep buffer = png_malloc(png_ptr,
+      height*width*pixel_size);
+
+   for (int i = 0; i < height, i++)
+      row_pointers[i] = buffer + i*width*pixel_size;
+
+   png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+If you use png_set_rows(), the application is responsible for freeing
+row_pointers (and row_pointers[i], if they were separately allocated).
+
+If you don't allocate row_pointers ahead of time, png_read_png() will
+do it, and it'll be free'ed by libpng when you call png_destroy_*().
+
+.SS The low-level read interface
+
+If you are going the low-level route, you are now ready to read all
+the file information up to the actual image data.  You do this with a
+call to png_read_info().
+
+    png_read_info(png_ptr, info_ptr);
+
+This will process all chunks up to but not including the image data.
+
+This also copies some of the data from the PNG file into the decode structure
+for use in later transformations.  Important information copied in is:
+
+1) The PNG file gamma from the gAMA chunk.  This overwrites the default value
+provided by an earlier call to png_set_gamma or png_set_alpha_mode.
+
+2) Prior to libpng-1.5.4 the background color from a bKGd chunk.  This
+damages the information provided by an earlier call to png_set_background
+resulting in unexpected behavior.  Libpng-1.5.4 no longer does this.
+
+3) The number of significant bits in each component value.  Libpng uses this to
+optimize gamma handling by reducing the internal lookup table sizes.
+
+4) The transparent color information from a tRNS chunk.  This can be modified by
+a later call to png_set_tRNS.
+
+.SS Querying the info structure
+
+Functions are used to get the information from the info_ptr once it
+has been read.  Note that these fields may not be completely filled
+in until png_read_end() has read the chunk data following the image.
+
+    png_get_IHDR(png_ptr, info_ptr, &width, &height,
+       &bit_depth, &color_type, &interlace_type,
+       &compression_type, &filter_method);
+
+    width          - holds the width of the image
+                     in pixels (up to 2^31).
+
+    height         - holds the height of the image
+                     in pixels (up to 2^31).
+
+    bit_depth      - holds the bit depth of one of the
+                     image channels.  (valid values are
+                     1, 2, 4, 8, 16 and depend also on
+                     the color_type.  See also
+                     significant bits (sBIT) below).
+
+    color_type     - describes which color/alpha channels
+                         are present.
+                     PNG_COLOR_TYPE_GRAY
+                        (bit depths 1, 2, 4, 8, 16)
+                     PNG_COLOR_TYPE_GRAY_ALPHA
+                        (bit depths 8, 16)
+                     PNG_COLOR_TYPE_PALETTE
+                        (bit depths 1, 2, 4, 8)
+                     PNG_COLOR_TYPE_RGB
+                        (bit_depths 8, 16)
+                     PNG_COLOR_TYPE_RGB_ALPHA
+                        (bit_depths 8, 16)
+
+                     PNG_COLOR_MASK_PALETTE
+                     PNG_COLOR_MASK_COLOR
+                     PNG_COLOR_MASK_ALPHA
+
+    interlace_type - (PNG_INTERLACE_NONE or
+                     PNG_INTERLACE_ADAM7)
+
+    compression_type - (must be PNG_COMPRESSION_TYPE_BASE
+                     for PNG 1.0)
+
+    filter_method  - (must be PNG_FILTER_TYPE_BASE
+                     for PNG 1.0, and can also be
+                     PNG_INTRAPIXEL_DIFFERENCING if
+                     the PNG datastream is embedded in
+                     a MNG-1.0 datastream)
+
+    Any of width, height, color_type, bit_depth,
+    interlace_type, compression_type, or filter_method can
+    be NULL if you are not interested in their values.
+
+    Note that png_get_IHDR() returns 32-bit data into
+    the application's width and height variables.
+    This is an unsafe situation if these are not png_uint_32
+    variables.  In such situations, the
+    png_get_image_width() and png_get_image_height()
+    functions described below are safer.
+
+    width            = png_get_image_width(png_ptr,
+                         info_ptr);
+
+    height           = png_get_image_height(png_ptr,
+                         info_ptr);
+
+    bit_depth        = png_get_bit_depth(png_ptr,
+                         info_ptr);
+
+    color_type       = png_get_color_type(png_ptr,
+                         info_ptr);
+
+    interlace_type   = png_get_interlace_type(png_ptr,
+                         info_ptr);
+
+    compression_type = png_get_compression_type(png_ptr,
+                         info_ptr);
+
+    filter_method    = png_get_filter_type(png_ptr,
+                         info_ptr);
+
+    channels = png_get_channels(png_ptr, info_ptr);
+
+    channels       - number of channels of info for the
+                     color type (valid values are 1 (GRAY,
+                     PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
+                     4 (RGB_ALPHA or RGB + filler byte))
+
+    rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+    rowbytes       - number of bytes needed to hold a row
+                     This value, the bit_depth, color_type,
+                     and the number of channels can change
+                     if you use transforms such as
+                     png_set_expand(). See
+                     png_read_update_info(), below.
+
+    signature = png_get_signature(png_ptr, info_ptr);
+
+    signature      - holds the signature read from the
+                     file (if any).  The data is kept in
+                     the same offset it would be if the
+                     whole signature were read (i.e. if an
+                     application had already read in 4
+                     bytes of signature before starting
+                     libpng, the remaining 4 bytes would
+                     be in signature[4] through signature[7]
+                     (see png_set_sig_bytes())).
+
+These are also important, but their validity depends on whether the chunk
+has been read.  The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
+png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
+data has been read, or zero if it is missing.  The parameters to the
+png_get_<chunk> are set directly if they are simple data types, or a
+pointer into the info_ptr is returned for any complex types.
+
+The colorspace data from gAMA, cHRM, sRGB, iCCP, and sBIT chunks
+is simply returned to give the application information about how the
+image was encoded.  Libpng itself only does transformations using the file
+gamma when combining semitransparent pixels with the background color, and,
+since libpng-1.6.0, when converting between 8-bit sRGB and 16-bit linear pixels
+within the simplified API.  Libpng also uses the file gamma when converting
+RGB to gray, beginning with libpng-1.0.5, if the application calls
+png_set_rgb_to_gray()).
+
+    png_get_PLTE(png_ptr, info_ptr, &palette,
+                     &num_palette);
+
+    palette        - the palette for the file
+                     (array of png_color)
+
+    num_palette    - number of entries in the palette
+
+    png_get_gAMA(png_ptr, info_ptr, &file_gamma);
+    png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
+
+    file_gamma     - the gamma at which the file is
+                     written (PNG_INFO_gAMA)
+
+    int_file_gamma - 100,000 times the gamma at which the
+                     file is written
+
+    png_get_cHRM(png_ptr, info_ptr,  &white_x, &white_y, &red_x,
+                     &red_y, &green_x, &green_y, &blue_x, &blue_y)
+    png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z,
+                     &green_X, &green_Y, &green_Z, &blue_X, &blue_Y,
+                     &blue_Z)
+    png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x,
+                     &int_white_y, &int_red_x, &int_red_y,
+                     &int_green_x, &int_green_y, &int_blue_x,
+                     &int_blue_y)
+    png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y,
+                     &int_red_Z, &int_green_X, &int_green_Y,
+                     &int_green_Z, &int_blue_X, &int_blue_Y,
+                     &int_blue_Z)
+
+    {white,red,green,blue}_{x,y}
+                     A color space encoding specified using the
+                     chromaticities of the end points and the
+                     white point. (PNG_INFO_cHRM)
+
+    {red,green,blue}_{X,Y,Z}
+                     A color space encoding specified using the
+                     encoding end points - the CIE tristimulus
+                     specification of the intended color of the red,
+                     green and blue channels in the PNG RGB data.
+                     The white point is simply the sum of the three
+                     end points. (PNG_INFO_cHRM)
+
+    png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
+
+    srgb_intent -    the rendering intent (PNG_INFO_sRGB)
+                     The presence of the sRGB chunk
+                     means that the pixel data is in the
+                     sRGB color space.  This chunk also
+                     implies specific values of gAMA and
+                     cHRM.
+
+    png_get_iCCP(png_ptr, info_ptr, &name,
+       &compression_type, &profile, &proflen);
+
+    name             - The profile name.
+
+    compression_type - The compression type; always
+                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+                       You may give NULL to this argument to
+                       ignore it.
+
+    profile          - International Color Consortium color
+                       profile data. May contain NULs.
+
+    proflen          - length of profile data in bytes.
+
+    png_get_sBIT(png_ptr, info_ptr, &sig_bit);
+
+    sig_bit        - the number of significant bits for
+                     (PNG_INFO_sBIT) each of the gray,
+                     red, green, and blue channels,
+                     whichever are appropriate for the
+                     given color type (png_color_16)
+
+    png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
+                     &num_trans, &trans_color);
+
+    trans_alpha    - array of alpha (transparency)
+                     entries for palette (PNG_INFO_tRNS)
+
+    num_trans      - number of transparent entries
+                     (PNG_INFO_tRNS)
+
+    trans_color    - graylevel or color sample values of
+                     the single transparent color for
+                     non-paletted images (PNG_INFO_tRNS)
+
+    png_get_eXIf_1(png_ptr, info_ptr, &num_exif, &exif);
+
+    exif           - Exif profile (array of png_byte)
+                     (PNG_INFO_eXIf)
+
+    png_get_hIST(png_ptr, info_ptr, &hist);
+
+    hist           - histogram of palette (array of
+                     png_uint_16) (PNG_INFO_hIST)
+
+    png_get_tIME(png_ptr, info_ptr, &mod_time);
+
+    mod_time       - time image was last modified
+                     (PNG_INFO_tIME)
+
+    png_get_bKGD(png_ptr, info_ptr, &background);
+
+    background     - background color (of type
+                     png_color_16p) (PNG_INFO_bKGD)
+                     valid 16-bit red, green and blue
+                     values, regardless of color_type
+
+    num_comments   = png_get_text(png_ptr, info_ptr,
+                     &text_ptr, &num_text);
+
+    num_comments   - number of comments
+
+    text_ptr       - array of png_text holding image
+                     comments
+
+    text_ptr[i].compression - type of compression used
+                 on "text" PNG_TEXT_COMPRESSION_NONE
+                           PNG_TEXT_COMPRESSION_zTXt
+                           PNG_ITXT_COMPRESSION_NONE
+                           PNG_ITXT_COMPRESSION_zTXt
+
+    text_ptr[i].key   - keyword for comment.  Must contain
+                         1-79 characters.
+
+    text_ptr[i].text  - text comments for current
+                         keyword.  Can be empty.
+
+    text_ptr[i].text_length - length of text string,
+                 after decompression, 0 for iTXt
+
+    text_ptr[i].itxt_length - length of itxt string,
+                 after decompression, 0 for tEXt/zTXt
+
+    text_ptr[i].lang  - language of comment (empty
+                         string for unknown).
+
+    text_ptr[i].lang_key  - keyword in UTF-8
+                         (empty string for unknown).
+
+    Note that the itxt_length, lang, and lang_key
+    members of the text_ptr structure only exist when the
+    library is built with iTXt chunk support.  Prior to
+    libpng-1.4.0 the library was built by default without
+    iTXt support. Also note that when iTXt is supported,
+    they contain NULL pointers when the "compression"
+    field contains PNG_TEXT_COMPRESSION_NONE or
+    PNG_TEXT_COMPRESSION_zTXt.
+
+    num_text       - number of comments (same as
+                     num_comments; you can put NULL here
+                     to avoid the duplication)
+
+    Note while png_set_text() will accept text, language,
+    and translated keywords that can be NULL pointers, the
+    structure returned by png_get_text will always contain
+    regular zero-terminated C strings.  They might be
+    empty strings but they will never be NULL pointers.
+
+    num_spalettes = png_get_sPLT(png_ptr, info_ptr,
+       &palette_ptr);
+
+    num_spalettes  - number of sPLT chunks read.
+
+    palette_ptr    - array of palette structures holding
+                     contents of one or more sPLT chunks
+                     read.
+
+    png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
+       &unit_type);
+
+    offset_x       - positive offset from the left edge
+                     of the screen (can be negative)
+
+    offset_y       - positive offset from the top edge
+                     of the screen (can be negative)
+
+    unit_type      - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+    png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
+       &unit_type);
+
+    res_x          - pixels/unit physical resolution in
+                     x direction
+
+    res_y          - pixels/unit physical resolution in
+                     x direction
+
+    unit_type      - PNG_RESOLUTION_UNKNOWN,
+                     PNG_RESOLUTION_METER
+
+    png_get_sCAL(png_ptr, info_ptr, &unit, &width,
+       &height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+
+    height      - height of a pixel in physical scale units
+                 (width and height are doubles)
+
+    png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
+       &height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+                  (expressed as a string)
+
+    height      - height of a pixel in physical scale units
+                 (width and height are strings like "2.54")
+
+    num_unknown_chunks = png_get_unknown_chunks(png_ptr,
+       info_ptr, &unknowns)
+
+    unknowns          - array of png_unknown_chunk
+                        structures holding unknown chunks
+
+    unknowns[i].name  - name of unknown chunk
+
+    unknowns[i].data  - data of unknown chunk
+
+    unknowns[i].size  - size of unknown chunk's data
+
+    unknowns[i].location - position of chunk in file
+
+    The value of "i" corresponds to the order in which the
+    chunks were read from the PNG file or inserted with the
+    png_set_unknown_chunks() function.
+
+    The value of "location" is a bitwise "or" of
+
+         PNG_HAVE_IHDR  (0x01)
+         PNG_HAVE_PLTE  (0x02)
+         PNG_AFTER_IDAT (0x08)
+
+The data from the pHYs chunk can be retrieved in several convenient
+forms:
+
+    res_x = png_get_x_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_y = png_get_y_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_x_and_y = png_get_pixels_per_meter(png_ptr,
+       info_ptr)
+
+    res_x = png_get_x_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    res_y = png_get_y_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    res_x_and_y = png_get_pixels_per_inch(png_ptr,
+       info_ptr)
+
+    aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
+       info_ptr)
+
+    Each of these returns 0 [signifying "unknown"] if
+       the data is not present or if res_x is 0;
+       res_x_and_y is 0 if res_x != res_y
+
+    Note that because of the way the resolutions are
+       stored internally, the inch conversions won't
+       come out to exactly even number.  For example,
+       72 dpi is stored as 0.28346 pixels/meter, and
+       when this is retrieved it is 71.9988 dpi, so
+       be sure to round the returned value appropriately
+       if you want to display a reasonable-looking result.
+
+The data from the oFFs chunk can be retrieved in several convenient
+forms:
+
+    x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
+
+    y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
+
+    x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
+
+    y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
+
+    Each of these returns 0 [signifying "unknown" if both
+       x and y are 0] if the data is not present or if the
+       chunk is present but the unit is the pixel.  The
+       remark about inexact inch conversions applies here
+       as well, because a value in inches can't always be
+       converted to microns and back without some loss
+       of precision.
+
+For more information, see the
+PNG specification for chunk contents.  Be careful with trusting
+rowbytes, as some of the transformations could increase the space
+needed to hold a row (expand, filler, gray_to_rgb, etc.).
+See png_read_update_info(), below.
+
+A quick word about text_ptr and num_text.  PNG stores comments in
+keyword/text pairs, one pair per chunk, with no limit on the number
+of text chunks, and a 2^31 byte limit on their size.  While there are
+suggested keywords, there is no requirement to restrict the use to these
+strings.  It is strongly suggested that keywords and text be sensible
+to humans (that's the point), so don't use abbreviations.  Non-printing
+symbols are not allowed.  See the PNG specification for more details.
+There is also no requirement to have text after the keyword.
+
+Keywords should be limited to 79 Latin-1 characters without leading or
+trailing spaces, but non-consecutive spaces are allowed within the
+keyword.  It is possible to have the same keyword any number of times.
+The text_ptr is an array of png_text structures, each holding a
+pointer to a language string, a pointer to a keyword and a pointer to
+a text string.  The text string, language code, and translated
+keyword may be empty or NULL pointers.  The keyword/text
+pairs are put into the array in the order that they are received.
+However, some or all of the text chunks may be after the image, so, to
+make sure you have read all the text chunks, don't mess with these
+until after you read the stuff after the image.  This will be
+mentioned again below in the discussion that goes with png_read_end().
+
+.SS Input transformations
+
+After you've read the header information, you can set up the library
+to handle any special transformations of the image data.  The various
+ways to transform the data will be described in the order that they
+should occur.  This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths.
+
+Transformations you request are ignored if they don't have any meaning for a
+particular input data format.  However some transformations can have an effect
+as a result of a previous transformation.  If you specify a contradictory set of
+transformations, for example both adding and removing the alpha channel, you
+cannot predict the final result.
+
+The color used for the transparency values should be supplied in the same
+format/depth as the current image data.  It is stored in the same format/depth
+as the image data in a tRNS chunk, so this is what libpng expects for this data.
+
+The color used for the background value depends on the need_expand argument as
+described below.
+
+Data will be decoded into the supplied row buffers packed into bytes
+unless the library has been told to transform it into another format.
+For example, 4 bit/pixel paletted or grayscale data will be returned
+2 pixels/byte with the leftmost pixel in the high-order bits of the byte,
+unless png_set_packing() is called.  8-bit RGB data will be stored
+in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
+is called to insert filler bytes, either before or after each RGB triplet.
+
+16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
+byte of the color value first, unless png_set_scale_16() is called to
+transform it to regular RGB RGB triplets, or png_set_filler() or
+png_set_add alpha() is called to insert two filler bytes, either before
+or after each RRGGBB triplet.  Similarly, 8-bit or 16-bit grayscale data can
+be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(),
+or png_set_scale_16().
+
+The following code transforms grayscale images of less than 8 to 8 bits,
+changes paletted images to RGB, and adds a full alpha channel if there is
+transparency information in a tRNS chunk.  This is most useful on
+grayscale images with bit depths of 2 or 4 or if there is a multiple-image
+viewing application that wishes to treat all images in the same way.
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+       png_set_palette_to_rgb(png_ptr);
+
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+       png_set_tRNS_to_alpha(png_ptr);
+
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+       png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+The first two functions are actually aliases for png_set_expand(), added
+in libpng version 1.0.4, with the function names expanded to improve code
+readability.  In some future version they may actually do different
+things.
+
+As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
+added.  It expands the sample depth without changing tRNS to alpha.
+
+As of libpng version 1.5.2, png_set_expand_16() was added.  It behaves as
+png_set_expand(); however, the resultant channels have 16 bits rather than 8.
+Use this when the output color or gray channels are made linear to avoid fairly
+severe accuracy loss.
+
+    if (bit_depth < 16)
+       png_set_expand_16(png_ptr);
+
+PNG can have files with 16 bits per channel.  If you only can handle
+8 bits per channel, this will strip the pixels down to 8-bit.
+
+    if (bit_depth == 16)
+    {
+#if PNG_LIBPNG_VER >= 10504
+       png_set_scale_16(png_ptr);
+#else
+       png_set_strip_16(png_ptr);
+#endif
+    }
+
+(The more accurate "png_set_scale_16()" API became available in libpng version
+1.5.4).
+
+If you need to process the alpha channel on the image separately from the image
+data (for example if you convert it to a bitmap mask) it is possible to have
+libpng strip the channel leaving just RGB or gray data:
+
+    if (color_type & PNG_COLOR_MASK_ALPHA)
+       png_set_strip_alpha(png_ptr);
+
+If you strip the alpha channel you need to find some other way of dealing with
+the information.  If, instead, you want to convert the image to an opaque
+version with no alpha channel use png_set_background; see below.
+
+As of libpng version 1.5.2, almost all useful expansions are supported, the
+major omissions are conversion of grayscale to indexed images (which can be
+done trivially in the application) and conversion of indexed to grayscale (which
+can be done by a trivial manipulation of the palette.)
+
+In the following table, the 01 means grayscale with depth<8, 31 means
+indexed with depth<8, other numerals represent the color type, "T" means
+the tRNS chunk is present, A means an alpha channel is present, and O
+means tRNS or alpha is present but all pixels in the image are opaque.
+
+  FROM  01  31   0  0T  0O   2  2T  2O   3  3T  3O  4A  4O  6A  6O
+   TO
+   01    -  [G]  -   -   -   -   -   -   -   -   -   -   -   -   -
+   31   [Q]  Q  [Q] [Q] [Q]  Q   Q   Q   Q   Q   Q  [Q] [Q]  Q   Q
+    0    1   G   +   .   .   G   G   G   G   G   G   B   B  GB  GB
+   0T    lt  Gt  t   +   .   Gt  G   G   Gt  G   G   Bt  Bt GBt GBt
+   0O    lt  Gt  t   .   +   Gt  Gt  G   Gt  Gt  G   Bt  Bt GBt GBt
+    2    C   P   C   C   C   +   .   .   C   -   -  CB  CB   B   B
+   2T    Ct  -   Ct  C   C   t   +   t   -   -   -  CBt CBt  Bt  Bt
+   2O    Ct  -   Ct  C   C   t   t   +   -   -   -  CBt CBt  Bt  Bt
+    3   [Q]  p  [Q] [Q] [Q]  Q   Q   Q   +   .   .  [Q] [Q]  Q   Q
+   3T   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   +   t  [Qt][Qt] Qt  Qt
+   3O   [Qt] p  [Qt][Q] [Q]  Qt  Qt  Qt  t   t   +  [Qt][Qt] Qt  Qt
+   4A    lA  G   A   T   T   GA  GT  GT  GA  GT  GT  +   BA  G  GBA
+   4O    lA GBA  A   T   T   GA  GT  GT  GA  GT  GT  BA  +  GBA  G
+   6A    CA  PA  CA  C   C   A   T  tT   PA  P   P   C  CBA  +   BA
+   6O    CA PBA  CA  C   C   A  tT   T   PA  P   P  CBA  C   BA  +
+
+Within the matrix,
+     "+" identifies entries where 'from' and 'to' are the same.
+     "-" means the transformation is not supported.
+     "." means nothing is necessary (a tRNS chunk can just be ignored).
+     "t" means the transformation is obtained by png_set_tRNS.
+     "A" means the transformation is obtained by png_set_add_alpha().
+     "X" means the transformation is obtained by png_set_expand().
+     "1" means the transformation is obtained by
+         png_set_expand_gray_1_2_4_to_8() (and by png_set_expand()
+         if there is no transparency in the original or the final
+         format).
+     "C" means the transformation is obtained by png_set_gray_to_rgb().
+     "G" means the transformation is obtained by png_set_rgb_to_gray().
+     "P" means the transformation is obtained by
+         png_set_expand_palette_to_rgb().
+     "p" means the transformation is obtained by png_set_packing().
+     "Q" means the transformation is obtained by png_set_quantize().
+     "T" means the transformation is obtained by
+         png_set_tRNS_to_alpha().
+     "B" means the transformation is obtained by
+         png_set_background(), or png_strip_alpha().
+
+When an entry has multiple transforms listed all are required to cause the
+right overall transformation.  When two transforms are separated by a comma
+either will do the job.  When transforms are enclosed in [] the transform should
+do the job but this is currently unimplemented - a different format will result
+if the suggested transformations are used.
+
+In PNG files, the alpha channel in an image
+is the level of opacity.  If you need the alpha channel in an image to
+be the level of transparency instead of opacity, you can invert the
+alpha channel (or the tRNS chunk data) after it's read, so that 0 is
+fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
+images) is fully transparent, with
+
+    png_set_invert_alpha(png_ptr);
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit
+files.  This code expands to 1 pixel per byte without changing the
+values of the pixels:
+
+    if (bit_depth < 8)
+       png_set_packing(png_ptr);
+
+PNG files have possible bit depths of 1, 2, 4, 8, and 16.  All pixels
+stored in a PNG image have been "scaled" or "shifted" up to the next
+higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
+to 8 bits/sample in the range [0, 255]).  However, it is also possible
+to convert the PNG pixel data back to the original bit depth of the
+image.  This call reduces the pixels back down to the original bit depth:
+
+    png_color_8p sig_bit;
+
+    if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
+       png_set_shift(png_ptr, sig_bit);
+
+PNG files store 3-color pixels in red, green, blue order.  This code
+changes the storage of the pixels to blue, green, red:
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_bgr(png_ptr);
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
+into 4 or 8 bytes for windowing systems that need them in this format:
+
+    if (color_type == PNG_COLOR_TYPE_RGB)
+       png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
+
+where "filler" is the 8-bit or 16-bit number to fill with, and the location
+is either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
+you want the filler before the RGB or after. When filling an 8-bit pixel,
+the least significant 8 bits of the number are used, if a 16-bit number is
+supplied.  This transformation does not affect images that already have full
+alpha channels.  To add an opaque alpha channel, use filler=0xffff and
+PNG_FILLER_AFTER which will generate RGBA pixels.
+
+Note that png_set_filler() does not change the color type.  If you want
+to do that, you can add a true alpha channel with
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_GRAY)
+       png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
+
+where "filler" contains the alpha value to assign to each pixel.
+The png_set_add_alpha() function was added in libpng-1.2.7.
+
+If you are reading an image with an alpha channel, and you need the
+data as ARGB instead of the normal PNG format RGBA:
+
+    if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_swap_alpha(png_ptr);
+
+For some uses, you may want a grayscale image to be represented as
+RGB.  This code will do that conversion:
+
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+       png_set_gray_to_rgb(png_ptr);
+
+Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
+with alpha.
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+       png_set_rgb_to_gray(png_ptr, error_action,
+          (double)red_weight, (double)green_weight);
+
+    error_action = 1: silently do the conversion
+
+    error_action = 2: issue a warning if the original
+                      image has any pixel where
+                      red != green or red != blue
+
+    error_action = 3: issue an error and abort the
+                      conversion if the original
+                      image has any pixel where
+                      red != green or red != blue
+
+    red_weight:       weight of red component
+
+    green_weight:     weight of green component
+                      If either weight is negative, default
+                      weights are used.
+
+In the corresponding fixed point API the red_weight and green_weight values are
+simply scaled by 100,000:
+
+    png_set_rgb_to_gray(png_ptr, error_action,
+       (png_fixed_point)red_weight,
+       (png_fixed_point)green_weight);
+
+If you have set error_action = 1 or 2, you can
+later check whether the image really was gray, after processing
+the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
+It will return a png_byte that is zero if the image was gray or
+1 if there were any non-gray pixels.  Background and sBIT data
+will be silently converted to grayscale, using the green channel
+data for sBIT, regardless of the error_action setting.
+
+The default values come from the PNG file cHRM chunk if present; otherwise, the
+defaults correspond to the ITU-R recommendation 709, and also the sRGB color
+space, as recommended in the Charles Poynton's Colour FAQ,
+Copyright (c) 2006-11-28 Charles Poynton, in section 9:
+
+<http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
+
+    Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
+
+Previous versions of this document, 1998 through 2002, recommended a slightly
+different formula:
+
+    Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+
+Libpng uses an integer approximation:
+
+    Y = (6968 * R + 23434 * G + 2366 * B)/32768
+
+The calculation is done in a linear colorspace, if the image gamma
+can be determined.
+
+The png_set_background() function has been described already; it tells libpng to
+composite images with alpha or simple transparency against the supplied
+background color.  For compatibility with versions of libpng earlier than
+libpng-1.5.4 it is recommended that you call the function after reading the file
+header, even if you don't want to use the color in a bKGD chunk, if one exists.
+
+If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
+you may use this color, or supply another color more suitable for
+the current display (e.g., the background color from a web page).  You
+need to tell libpng how the color is represented, both the format of the
+component values in the color (the number of bits) and the gamma encoding of the
+color.  The function takes two arguments, background_gamma_mode and need_expand
+to convey this information; however, only two combinations are likely to be
+useful:
+
+    png_color_16 my_background;
+    png_color_16p image_background;
+
+    if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+       png_set_background(png_ptr, image_background,
+           PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
+    else
+       png_set_background(png_ptr, &my_background,
+           PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
+
+The second call was described above - my_background is in the format of the
+final, display, output produced by libpng.  Because you now know the format of
+the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
+output and to retain palette images (the palette colors will be modified
+appropriately and the tRNS chunk removed.)  However, if you are doing this,
+take great care not to ask for transformations without checking first that
+they apply!
+
+In the first call the background color has the original bit depth and color type
+of the PNG file.  So, for palette images the color is supplied as a palette
+index and for low bit greyscale images the color is a reduced bit value in
+image_background->gray.
+
+If you didn't call png_set_gamma() before reading the file header, for example
+if you need your code to remain compatible with older versions of libpng prior
+to libpng-1.5.4, this is the place to call it.
+
+Do not call it if you called png_set_alpha_mode(); doing so will damage the
+settings put in place by png_set_alpha_mode().  (If png_set_alpha_mode() is
+supported then you can certainly do png_set_gamma() before reading the PNG
+header.)
+
+This API unconditionally sets the screen and file gamma values, so it will
+override the value in the PNG file unless it is called before the PNG file
+reading starts.  For this reason you must always call it with the PNG file
+value when you call it in this position:
+
+   if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
+      png_set_gamma(png_ptr, screen_gamma, file_gamma);
+
+   else
+      png_set_gamma(png_ptr, screen_gamma, 0.45455);
+
+If you need to reduce an RGB file to a paletted file, or if a paletted
+file has more entries than will fit on your screen, png_set_quantize()
+will do that.  Note that this is a simple match quantization that merely
+finds the closest color available.  This should work fairly well with
+optimized palettes, but fairly badly with linear color cubes.  If you
+pass a palette that is larger than maximum_colors, the file will
+reduce the number of colors in the palette so it will fit into
+maximum_colors.  If there is a histogram, libpng will use it to make
+more intelligent choices when reducing the palette.  If there is no
+histogram, it may not do as good a job.
+
+   if (color_type & PNG_COLOR_MASK_COLOR)
+   {
+      if (png_get_valid(png_ptr, info_ptr,
+          PNG_INFO_PLTE))
+      {
+         png_uint_16p histogram = NULL;
+
+         png_get_hIST(png_ptr, info_ptr,
+             &histogram);
+         png_set_quantize(png_ptr, palette, num_palette,
+            max_screen_colors, histogram, 1);
+      }
+
+      else
+      {
+         png_color std_color_cube[MAX_SCREEN_COLORS] =
+            { ... colors ... };
+
+         png_set_quantize(png_ptr, std_color_cube,
+            MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
+            NULL,0);
+      }
+   }
+
+PNG files describe monochrome as black being zero and white being one.
+The following code will reverse this (make black be one and white be
+zero):
+
+   if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
+      png_set_invert_mono(png_ptr);
+
+This function can also be used to invert grayscale and gray-alpha images:
+
+   if (color_type == PNG_COLOR_TYPE_GRAY ||
+       color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      png_set_invert_mono(png_ptr);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first).  This code changes the storage to the
+other way (little-endian, i.e. least significant bits first, the
+way PCs store them):
+
+    if (bit_depth == 16)
+       png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+    if (bit_depth < 8)
+       png_set_packswap(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs.  This is done by setting a callback
+with
+
+    png_set_read_user_transform_fn(png_ptr,
+        read_transform_fn);
+
+You must supply the function
+
+    void read_transform_fn(png_structp png_ptr, png_row_infop
+        row_info, png_bytep data)
+
+See pngtest.c for a working example.  Your function will be called
+after all of the other transformations have been processed.  Take care with
+interlaced images if you do the interlace yourself - the width of the row is the
+width in 'row_info', not the overall image width.
+
+If supported, libpng provides two information routines that you can use to find
+where you are in processing the image:
+
+   png_get_current_pass_number(png_structp png_ptr);
+   png_get_current_row_number(png_structp png_ptr);
+
+Don't try using these outside a transform callback - firstly they are only
+supported if user transforms are supported, secondly they may well return
+unexpected results unless the row is actually being processed at the moment they
+are called.
+
+With interlaced
+images the value returned is the row in the input sub-image image.  Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function, and you can inform libpng that your transform
+function will change the number of channels or bit depth with the
+function
+
+    png_set_user_transform_info(png_ptr, user_ptr,
+        user_depth, user_channels);
+
+The user's application, not libpng, is responsible for allocating and
+freeing any memory required for the user structure.
+
+You can retrieve the pointer via the function
+png_get_user_transform_ptr().  For example:
+
+    voidp read_user_transform_ptr =
+        png_get_user_transform_ptr(png_ptr);
+
+The last thing to handle is interlacing; this is covered in detail below,
+but you must call the function here if you want libpng to handle expansion
+of the interlaced image.
+
+    number_of_passes = png_set_interlace_handling(png_ptr);
+
+After setting the transformations, libpng can update your png_info
+structure to reflect any transformations you've requested with this
+call.
+
+    png_read_update_info(png_ptr, info_ptr);
+
+This is most useful to update the info structure's rowbytes
+field so you can use it to allocate your image memory.  This function
+will also update your palette with the correct screen_gamma and
+background if these have been given with the calls above.  You may
+only call png_read_update_info() once with a particular info_ptr.
+
+After you call png_read_update_info(), you can allocate any
+memory you need to hold the image.  The row data is simply
+raw byte data for all forms of images.  As the actual allocation
+varies among applications, no example will be given.  If you
+are allocating one large chunk, you will need to build an
+array of pointers to each row, as it will be needed for some
+of the functions below.
+
+Be sure that your platform can allocate the buffer that you'll need.
+libpng internally checks for oversize width, but you'll need to
+do your own check for number_of_rows*width*pixel_size if you are using
+a multiple-row buffer:
+
+   /* Guard against integer overflow */
+   if (number_of_rows > PNG_SIZE_MAX/(width*pixel_size))
+      png_error(png_ptr, "image_data buffer would be too large");
+
+Remember: Before you call png_read_update_info(), the png_get_*()
+functions return the values corresponding to the original PNG image.
+After you call png_read_update_info the values refer to the image
+that libpng will output.  Consequently you must call all the png_set_
+functions before you call png_read_update_info().  This is particularly
+important for png_set_interlace_handling() - if you are going to call
+png_read_update_info() you must call png_set_interlace_handling() before
+it unless you want to receive interlaced output.
+
+.SS Reading image data
+
+After you've allocated memory, you can read the image data.
+The simplest way to do this is in one function call.  If you are
+allocating enough memory to hold the whole image, you can just
+call png_read_image() and libpng will read in all the image data
+and put it in the memory area supplied.  You will need to pass in
+an array of pointers to each row.
+
+This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() (unless you call
+png_read_update_info()) or call this function multiple times, or any
+of that other stuff necessary with png_read_rows().
+
+   png_read_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+   png_bytep row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to read in the whole image at once, you can
+use png_read_rows() instead.  If there is no interlacing (check
+interlace_type == PNG_INTERLACE_NONE), this is simple:
+
+    png_read_rows(png_ptr, row_pointers, NULL,
+        number_of_rows);
+
+where row_pointers is the same as in the png_read_image() call.
+
+If you are doing this just one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+    png_bytep row_pointer = row;
+    png_read_row(png_ptr, row_pointer, NULL);
+
+If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
+get somewhat harder.  The only current (PNG Specification version 1.2)
+interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
+a somewhat complicated 2D interlace scheme, known as Adam7, that
+breaks down an image into seven smaller images of varying size, based
+on an 8x8 grid.  This number is defined (from libpng 1.5) as
+PNG_INTERLACE_ADAM7_PASSES in png.h
+
+libpng can fill out those images or it can give them to you "as is".
+It is almost always better to have libpng handle the interlacing for you.
+If you want the images filled out, there are two ways to do that.  The one
+mentioned in the PNG specification is to expand each pixel to cover
+those pixels that have not been read yet (the "rectangle" method).
+This results in a blocky image for the first pass, which gradually
+smooths out as more pixels are read.  The other method is the "sparkle"
+method, where pixels are drawn only in their final locations, with the
+rest of the image remaining whatever colors they were initialized to
+before the start of the read.  The first method usually looks better,
+but tends to be slower, as there are more pixels to put in the rows.
+
+If, as is likely, you want libpng to expand the images, call this before
+calling png_start_read_image() or png_read_update_info():
+
+    if (interlace_type == PNG_INTERLACE_ADAM7)
+       number_of_passes
+           = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed.  Currently, this is seven,
+but may change if another interlace type is added.  This function can be
+called even if the file is not interlaced, where it will return one pass.
+You then need to read the whole image 'number_of_passes' times.  Each time
+will distribute the pixels from the current pass to the correct place in
+the output image, so you need to supply the same rows to png_read_rows in
+each pass.
+
+If you are not going to display the image after each pass, but are
+going to wait until the entire image is read in, use the sparkle
+effect.  This effect is faster and the end result of either method
+is exactly the same.  If you are planning on displaying the image
+after each pass, the "rectangle" effect is generally considered the
+better looking one.
+
+If you only want the "sparkle" effect, just call png_read_row() or
+png_read_rows() as
+normal, with the third parameter NULL.  Make sure you make pass over
+the image number_of_passes times, and you don't change the data in the
+rows between calls.  You can change the locations of the data, just
+not the data.  Each pass only writes the pixels appropriate for that
+pass, and assumes the data from previous passes is still valid.
+
+    png_read_rows(png_ptr, row_pointers, NULL,
+        number_of_rows);
+    or
+    png_read_row(png_ptr, row_pointers, NULL);
+
+If you only want the first effect (the rectangles), do the same as
+before except pass the row buffer in the third parameter, and leave
+the second parameter NULL.
+
+    png_read_rows(png_ptr, NULL, row_pointers,
+        number_of_rows);
+    or
+    png_read_row(png_ptr, NULL, row_pointers);
+
+If you don't want libpng to handle the interlacing details, just call
+png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
+Each of the images is a valid image by itself; however, you will almost
+certainly need to distribute the pixels from each sub-image to the
+correct place.  This is where everything gets very tricky.
+
+If you want to retrieve the separate images you must pass the correct
+number of rows to each successive call of png_read_rows().  The calculation
+gets pretty complicated for small images, where some sub-images may
+not even exist because either their width or height ends up zero.
+libpng provides two macros to help you in 1.5 and later versions:
+
+   png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
+   png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
+
+Respectively these tell you the width and height of the sub-image
+corresponding to the numbered pass.  'pass' is in in the range 0 to 6 -
+this can be confusing because the specification refers to the same passes
+as 1 to 7!  Be careful, you must check both the width and height before
+calling png_read_rows() and not call it for that pass if either is zero.
+
+You can, of course, read each sub-image row by row.  If you want to
+produce optimal code to make a pixel-by-pixel transformation of an
+interlaced image this is the best approach; read each row of each pass,
+transform it, and write it out to a new interlaced image.
+
+If you want to de-interlace the image yourself libpng provides further
+macros to help that tell you where to place the pixels in the output image.
+Because the interlacing scheme is rectangular - sub-image pixels are always
+arranged on a rectangular grid - all you need to know for each pass is the
+starting column and row in the output image of the first pixel plus the
+spacing between each pixel.  As of libpng 1.5 there are four macros to
+retrieve this information:
+
+   png_uint_32 x = PNG_PASS_START_COL(pass);
+   png_uint_32 y = PNG_PASS_START_ROW(pass);
+   png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
+   png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
+
+These allow you to write the obvious loop:
+
+   png_uint_32 input_y = 0;
+   png_uint_32 output_y = PNG_PASS_START_ROW(pass);
+
+   while (output_y < output_image_height)
+   {
+      png_uint_32 input_x = 0;
+      png_uint_32 output_x = PNG_PASS_START_COL(pass);
+
+      while (output_x < output_image_width)
+      {
+         image[output_y][output_x] =
+             subimage[pass][input_y][input_x++];
+
+         output_x += xStep;
+      }
+
+      ++input_y;
+      output_y += yStep;
+   }
+
+Notice that the steps between successive output rows and columns are
+returned as shifts.  This is possible because the pixels in the subimages
+are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
+image.  In practice you may need to directly calculate the output coordinate
+given an input coordinate.  libpng provides two further macros for this
+purpose:
+
+   png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
+   png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
+
+Finally a pair of macros are provided to tell you if a particular image
+row or column appears in a given pass:
+
+   int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
+   int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
+
+Bear in mind that you will probably also need to check the width and height
+of the pass in addition to the above to be sure the pass even exists!
+
+With any luck you are convinced by now that you don't want to do your own
+interlace handling.  In reality normally the only good reason for doing this
+is if you are processing PNG files on a pixel-by-pixel basis and don't want
+to load the whole file into memory when it is interlaced.
+
+libpng includes a test program, pngvalid, that illustrates reading and
+writing of interlaced images.  If you can't get interlacing to work in your
+code and don't want to leave it to libpng (the recommended approach), see
+how pngvalid.c does it.
+
+.SS Finishing a sequential read
+
+After you are finished reading the image through the
+low-level interface, you can finish reading the file.
+
+If you want to use a different crc action for handling CRC errors in
+chunks after the image data, you can call png_set_crc_action()
+again at this point.
+
+If you are interested in comments or time, which may be stored either
+before or after the image data, you should pass the separate png_info
+struct if you want to keep the comments from before and after the image
+separate.
+
+    png_infop end_info = png_create_info_struct(png_ptr);
+
+    if (!end_info)
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+       return ERROR;
+    }
+
+    png_read_end(png_ptr, end_info);
+
+If you are not interested, you should still call png_read_end()
+but you can pass NULL, avoiding the need to create an end_info structure.
+If you do this, libpng will not process any chunks after IDAT other than
+skipping over them and perhaps (depending on whether you have called
+png_set_crc_action) checking their CRCs while looking for the IEND chunk.
+
+   png_read_end(png_ptr, NULL);
+
+If you don't call png_read_end(), then your file pointer will be
+left pointing to the first chunk after the last IDAT, which is probably
+not what you want if you expect to read something beyond the end of
+the PNG datastream.
+
+When you are done, you can free all memory allocated by libpng like this:
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
+
+or, if you didn't create an end_info structure,
+
+   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+    png_free_data(png_ptr, info_ptr, mask, seq)
+
+    mask - identifies data to be freed, a mask
+           containing the bitwise OR of one or
+           more of
+             PNG_FREE_PLTE, PNG_FREE_TRNS,
+             PNG_FREE_HIST, PNG_FREE_ICCP,
+             PNG_FREE_PCAL, PNG_FREE_ROWS,
+             PNG_FREE_SCAL, PNG_FREE_SPLT,
+             PNG_FREE_TEXT, PNG_FREE_UNKN,
+           or simply PNG_FREE_ALL
+
+    seq  - sequence number of item to be freed
+           (\-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng,  and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed.  If "seq" is not \-1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+The default behavior is only to free data that was allocated internally
+by libpng.  This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+    png_data_freer(png_ptr, info_ptr, freer, mask)
+
+    freer  - one of
+               PNG_DESTROY_WILL_FREE_DATA
+               PNG_SET_WILL_FREE_DATA
+               PNG_USER_WILL_FREE_DATA
+
+    mask   - which data elements are affected
+             same choices as in png_free_data()
+
+This function only affects data that has already been allocated.
+You can call this function after reading the PNG data but before calling
+any png_set_*() functions, to control whether the user or the png_set_*()
+function is responsible for freeing any existing data that might be present,
+and again after the png_set_*() functions to control whether the user
+or png_destroy_*() is supposed to free the data.  When the user assumes
+responsibility for libpng-allocated data, the application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated your row_pointers in a single block, as suggested above in
+the description of the high level read interface, you must not transfer
+responsibility for freeing it to the png_set_rows or png_read_destroy function,
+because they would also try to free the individual row_pointers[i].
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key.  Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+
+The png_free_data() function will turn off the "valid" flag for anything
+it frees.  If you need to turn the flag off for a chunk that was freed by
+your application instead of by libpng, you can use
+
+    png_set_invalid(png_ptr, info_ptr, mask);
+
+    mask - identifies the chunks to be made invalid,
+           containing the bitwise OR of one or
+           more of
+             PNG_INFO_gAMA, PNG_INFO_sBIT,
+             PNG_INFO_cHRM, PNG_INFO_PLTE,
+             PNG_INFO_tRNS, PNG_INFO_bKGD,
+             PNG_INFO_eXIf,
+             PNG_INFO_hIST, PNG_INFO_pHYs,
+             PNG_INFO_oFFs, PNG_INFO_tIME,
+             PNG_INFO_pCAL, PNG_INFO_sRGB,
+             PNG_INFO_iCCP, PNG_INFO_sPLT,
+             PNG_INFO_sCAL, PNG_INFO_IDAT
+
+For a more compact example of reading a PNG image, see the file example.c.
+
+.SS Reading PNG files progressively
+
+The progressive reader is slightly different from the non-progressive
+reader.  Instead of calling png_read_info(), png_read_rows(), and
+png_read_end(), you make one call to png_process_data(), which calls
+callbacks when it has the info, a row, or the end of the image.  You
+set up these callbacks with png_set_progressive_read_fn().  You don't
+have to worry about the input/output functions of libpng, as you are
+giving the library the data directly in png_process_data().  I will
+assume that you have read the section on reading PNG files above,
+so I will only highlight the differences (although I will show
+all of the code).
+
+png_structp png_ptr;
+png_infop info_ptr;
+
+ /*  An example code fragment of how you would
+     initialize the progressive reader in your
+     application. */
+ int
+ initialize_png_reader()
+ {
+    png_ptr = png_create_read_struct
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+         user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+        return ERROR;
+
+    info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+    {
+       png_destroy_read_struct(&png_ptr, NULL, NULL);
+       return ERROR;
+    }
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+       return ERROR;
+    }
+
+    /* This one's new.  You can provide functions
+       to be called when the header info is valid,
+       when each row is completed, and when the image
+       is finished.  If you aren't using all functions,
+       you can specify NULL parameters.  Even when all
+       three functions are NULL, you need to call
+       png_set_progressive_read_fn().  You can use
+       any struct as the user_ptr (cast to a void pointer
+       for the function call), and retrieve the pointer
+       from inside the callbacks using the function
+
+          png_get_progressive_ptr(png_ptr);
+
+       which will return a void pointer, which you have
+       to cast appropriately.
+     */
+    png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
+        info_callback, row_callback, end_callback);
+
+    return 0;
+ }
+
+ /* A code fragment that you call as you receive blocks
+   of data */
+ int
+ process_data(png_bytep buffer, png_uint_32 length)
+ {
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+       return ERROR;
+    }
+
+    /* This one's new also.  Simply give it a chunk
+       of data from the file stream (in order, of
+       course).  On machines with segmented memory
+       models machines, don't give it any more than
+       64K.  The library seems to run fine with sizes
+       of 4K. Although you can give it much less if
+       necessary (I assume you can give it chunks of
+       1 byte, I haven't tried less than 256 bytes
+       yet).  When this function returns, you may
+       want to display any rows that were generated
+       in the row callback if you don't already do
+       so there.
+     */
+    png_process_data(png_ptr, info_ptr, buffer, length);
+
+    /* At this point you can call png_process_data_skip if
+       you want to handle data the library will skip yourself;
+       it simply returns the number of bytes to skip (and stops
+       libpng skipping that number of bytes on the next
+       png_process_data call).
+    return 0;
+ }
+
+ /* This function is called (as set by
+    png_set_progressive_read_fn() above) when enough data
+    has been supplied so all of the header has been
+    read.
+ */
+ void
+ info_callback(png_structp png_ptr, png_infop info)
+ {
+    /* Do any setup here, including setting any of
+       the transformations mentioned in the Reading
+       PNG files section.  For now, you _must_ call
+       either png_start_read_image() or
+       png_read_update_info() after all the
+       transformations are set (even if you don't set
+       any).  You may start getting rows before
+       png_process_data() returns, so this is your
+       last chance to prepare for that.
+
+       This is where you turn on interlace handling,
+       assuming you don't want to do it yourself.
+
+       If you need to you can stop the processing of
+       your original input data at this point by calling
+       png_process_data_pause.  This returns the number
+       of unprocessed bytes from the last png_process_data
+       call - it is up to you to ensure that the next call
+       sees these bytes again.  If you don't want to bother
+       with this you can get libpng to cache the unread
+       bytes by setting the 'save' parameter (see png.h) but
+       then libpng will have to copy the data internally.
+     */
+ }
+
+ /* This function is called when each row of image
+    data is complete */
+ void
+ row_callback(png_structp png_ptr, png_bytep new_row,
+    png_uint_32 row_num, int pass)
+ {
+    /* If the image is interlaced, and you turned
+       on the interlace handler, this function will
+       be called for every row in every pass.  Some
+       of these rows will not be changed from the
+       previous pass.  When the row is not changed,
+       the new_row variable will be NULL.  The rows
+       and passes are called in order, so you don't
+       really need the row_num and pass, but I'm
+       supplying them because it may make your life
+       easier.
+
+       If you did not turn on interlace handling then
+       the callback is called for each row of each
+       sub-image when the image is interlaced.  In this
+       case 'row_num' is the row in the sub-image, not
+       the row in the output image as it is in all other
+       cases.
+
+       For the non-NULL rows of interlaced images when
+       you have switched on libpng interlace handling,
+       you must call png_progressive_combine_row()
+       passing in the row and the old row.  You can
+       call this function for NULL rows (it will just
+       return) and for non-interlaced images (it just
+       does the memcpy for you) if it will make the
+       code easier.  Thus, you can just do this for
+       all cases if you switch on interlace handling;
+     */
+
+        png_progressive_combine_row(png_ptr, old_row,
+          new_row);
+
+    /* where old_row is what was displayed
+       previously for the row.  Note that the first
+       pass (pass == 0, really) will completely cover
+       the old row, so the rows do not have to be
+       initialized.  After the first pass (and only
+       for interlaced images), you will have to pass
+       the current row, and the function will combine
+       the old row and the new row.
+
+       You can also call png_process_data_pause in this
+       callback - see above.
+    */
+ }
+
+ void
+ end_callback(png_structp png_ptr, png_infop info)
+ {
+    /* This function is called after the whole image
+       has been read, including any chunks after the
+       image (up to and including the IEND).  You
+       will usually have the same info chunk as you
+       had in the header, although some data may have
+       been added to the comments and time fields.
+
+       Most people won't do much here, perhaps setting
+       a flag that marks the image as finished.
+     */
+ }
+
+
+
+.SH IV. Writing
+
+Much of this is very similar to reading.  However, everything of
+importance is repeated here, so you won't have to constantly look
+back up in the reading section to understand writing.
+
+.SS Setup
+
+You will want to do the I/O initialization before you get into libpng,
+so if it doesn't work, you don't have anything to undo. If you are not
+using the standard I/O functions, you will need to replace them with
+custom writing functions.  See the discussion under Customizing libpng.
+
+    FILE *fp = fopen(file_name, "wb");
+
+    if (!fp)
+       return ERROR;
+
+Next, png_struct and png_info need to be allocated and initialized.
+As these can be both relatively large, you may not want to store these
+on the stack, unless you have stack space to spare.  Of course, you
+will want to check if they return NULL.  If you are also reading,
+you won't want to name your read structure and your write structure
+both "png_ptr"; you can call them anything you like, such as
+"read_ptr" and "write_ptr".  Look at pngtest.c, for example.
+
+    png_structp png_ptr = png_create_write_struct
+       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn);
+
+    if (!png_ptr)
+       return ERROR;
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr)
+    {
+       png_destroy_write_struct(&png_ptr, NULL);
+       return ERROR;
+    }
+
+If you want to use your own memory allocation routines,
+define PNG_USER_MEM_SUPPORTED and use
+png_create_write_struct_2() instead of png_create_write_struct():
+
+    png_structp png_ptr = png_create_write_struct_2
+       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        user_error_fn, user_warning_fn, (png_voidp)
+        user_mem_ptr, user_malloc_fn, user_free_fn);
+
+After you have these structures, you will need to set up the
+error handling.  When libpng encounters an error, it expects to
+longjmp() back to your routine.  Therefore, you will need to call
+setjmp() and pass the png_jmpbuf(png_ptr).  If you
+write the file from different routines, you will need to update
+the png_jmpbuf(png_ptr) every time you enter a new routine that will
+call a png_*() function.  See your documentation of setjmp/longjmp
+for your compiler for more information on setjmp/longjmp.  See
+the discussion on libpng error handling in the Customizing Libpng
+section below for more information on the libpng error handling.
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+    {
+       png_destroy_write_struct(&png_ptr, &info_ptr);
+       fclose(fp);
+       return ERROR;
+    }
+    ...
+    return;
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+   png_set_check_for_invalid_index(png_ptr, 0);
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are written as-is by the encoder, resulting in an
+invalid PNG datastream as output.  In this case the application is
+responsible for ensuring that the pixel indexes are in range when it writes
+a PLTE chunk with fewer entries than the bit depth would allow.
+
+Now you need to set up the output code.  The default for libpng is to
+use the C function fwrite().  If you use this, you will need to pass a
+valid FILE * in the function png_init_io().  Be sure that the file is
+opened in binary mode.  Again, if you wish to handle writing data in
+another way, see the discussion on libpng I/O handling in the Customizing
+Libpng section below.
+
+    png_init_io(png_ptr, fp);
+
+If you are embedding your PNG into a datastream such as MNG, and don't
+want libpng to write the 8-byte signature, or if you have already
+written the signature in your application, use
+
+    png_set_sig_bytes(png_ptr, 8);
+
+to inform libpng that it should not write a signature.
+
+.SS Write callbacks
+
+At this point, you can set up a callback function that will be
+called after each row has been written, which you can use to control
+a progress meter or the like.  It's demonstrated in pngtest.c.
+You must supply a function
+
+    void write_row_callback(png_structp png_ptr, png_uint_32 row,
+       int pass)
+    {
+       /* put your code here */
+    }
+
+(You can give it another name that you like instead of "write_row_callback")
+
+To inform libpng about your function, use
+
+    png_set_write_status_fn(png_ptr, write_row_callback);
+
+When this function is called the row has already been completely processed and
+it has also been written out.  The 'row' and 'pass' refer to the next row to be
+handled.  For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0.  For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes.  Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass\-1', if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+You now have the option of modifying how the compression library will
+run.  The following functions are mainly for testing, but may be useful
+in some cases, like if you need to write PNG files extremely fast and
+are willing to give up some compression, or if you want to get the
+maximum possible compression at the expense of slower writing.  If you
+have no special needs in this area, let the library do what it wants by
+not calling this function at all, as it has been tuned to deliver a good
+speed/compression ratio. The second parameter to png_set_filter() is
+the filter method, for which the only valid values are 0 (as of the
+July 1999 PNG specification, version 1.2) or 64 (if you are writing
+a PNG datastream that is to be embedded in a MNG datastream).  The third
+parameter is a flag that indicates which filter type(s) are to be tested
+for each scanline.  See the PNG specification for details on the specific
+filter types.
+
+
+    /* turn on or off filtering, and/or choose
+       specific filters.  You can use either a single
+       PNG_FILTER_VALUE_NAME or the bitwise OR of one
+       or more PNG_FILTER_NAME masks.
+     */
+    png_set_filter(png_ptr, 0,
+       PNG_FILTER_NONE  | PNG_FILTER_VALUE_NONE |
+       PNG_FILTER_SUB   | PNG_FILTER_VALUE_SUB  |
+       PNG_FILTER_UP    | PNG_FILTER_VALUE_UP   |
+       PNG_FILTER_AVG   | PNG_FILTER_VALUE_AVG  |
+       PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
+       PNG_ALL_FILTERS  | PNG_FAST_FILTERS);
+
+If an application wants to start and stop using particular filters during
+compression, it should start out with all of the filters (to ensure that
+the previous row of pixels will be stored in case it's needed later),
+and then add and remove them after the start of compression.
+
+If you are writing a PNG datastream that is to be embedded in a MNG
+datastream, the second parameter can be either 0 or 64.
+
+The png_set_compression_*() functions interface to the zlib compression
+library, and should mostly be ignored unless you really know what you are
+doing.  The only generally useful call is png_set_compression_level()
+which changes how much time zlib spends on trying to compress the image
+data.  See the Compression Library (zlib.h and algorithm.txt, distributed
+with zlib) for details on the compression levels.
+
+    #include zlib.h
+
+    /* Set the zlib compression level */
+    png_set_compression_level(png_ptr,
+        Z_BEST_COMPRESSION);
+
+    /* Set other zlib parameters for compressing IDAT */
+    png_set_compression_mem_level(png_ptr, 8);
+    png_set_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_compression_window_bits(png_ptr, 15);
+    png_set_compression_method(png_ptr, 8);
+    png_set_compression_buffer_size(png_ptr, 8192)
+
+    /* Set zlib parameters for text compression
+     * If you don't call these, the parameters
+     * fall back on those defined for IDAT chunks
+     */
+    png_set_text_compression_mem_level(png_ptr, 8);
+    png_set_text_compression_strategy(png_ptr,
+        Z_DEFAULT_STRATEGY);
+    png_set_text_compression_window_bits(png_ptr, 15);
+    png_set_text_compression_method(png_ptr, 8);
+
+.SS Setting the contents of info for output
+
+You now need to fill in the png_info structure with all the data you
+wish to write before the actual image.  Note that the only thing you
+are allowed to write after the image is the text chunks and the time
+chunk (as of PNG Specification 1.2, anyway).  See png_write_end() and
+the latest PNG specification for more information on that.  If you
+wish to write them before the image, fill them in now, and flag that
+data as being valid.  If you want to wait until after the data, don't
+fill them until png_write_end().  For all the fields in png_info and
+their data types, see png.h.  For explanations of what the fields
+contain, see the PNG specification.
+
+Some of the more important parts of the png_info are:
+
+    png_set_IHDR(png_ptr, info_ptr, width, height,
+       bit_depth, color_type, interlace_type,
+       compression_type, filter_method)
+
+    width          - holds the width of the image
+                     in pixels (up to 2^31).
+
+    height         - holds the height of the image
+                     in pixels (up to 2^31).
+
+    bit_depth      - holds the bit depth of one of the
+                     image channels.
+                     (valid values are 1, 2, 4, 8, 16
+                     and depend also on the
+                     color_type.  See also significant
+                     bits (sBIT) below).
+
+    color_type     - describes which color/alpha
+                     channels are present.
+                     PNG_COLOR_TYPE_GRAY
+                        (bit depths 1, 2, 4, 8, 16)
+                     PNG_COLOR_TYPE_GRAY_ALPHA
+                        (bit depths 8, 16)
+                     PNG_COLOR_TYPE_PALETTE
+                        (bit depths 1, 2, 4, 8)
+                     PNG_COLOR_TYPE_RGB
+                        (bit_depths 8, 16)
+                     PNG_COLOR_TYPE_RGB_ALPHA
+                        (bit_depths 8, 16)
+
+                     PNG_COLOR_MASK_PALETTE
+                     PNG_COLOR_MASK_COLOR
+                     PNG_COLOR_MASK_ALPHA
+
+    interlace_type - PNG_INTERLACE_NONE or
+                     PNG_INTERLACE_ADAM7
+
+    compression_type - (must be
+                     PNG_COMPRESSION_TYPE_DEFAULT)
+
+    filter_method  - (must be PNG_FILTER_TYPE_DEFAULT
+                     or, if you are writing a PNG to
+                     be embedded in a MNG datastream,
+                     can also be
+                     PNG_INTRAPIXEL_DIFFERENCING)
+
+If you call png_set_IHDR(), the call must appear before any of the
+other png_set_*() functions, because they might require access to some of
+the IHDR settings.  The remaining png_set_*() functions can be called
+in any order.
+
+If you wish, you can reset the compression_type, interlace_type, or
+filter_method later by calling png_set_IHDR() again; if you do this, the
+width, height, bit_depth, and color_type must be the same in each call.
+
+    png_set_PLTE(png_ptr, info_ptr, palette,
+       num_palette);
+
+    palette        - the palette for the file
+                     (array of png_color)
+    num_palette    - number of entries in the palette
+
+
+    png_set_gAMA(png_ptr, info_ptr, file_gamma);
+    png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
+
+    file_gamma     - the gamma at which the image was
+                     created (PNG_INFO_gAMA)
+
+    int_file_gamma - 100,000 times the gamma at which
+                     the image was created
+
+    png_set_cHRM(png_ptr, info_ptr,  white_x, white_y, red_x, red_y,
+                     green_x, green_y, blue_x, blue_y)
+    png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X,
+                     green_Y, green_Z, blue_X, blue_Y, blue_Z)
+    png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y,
+                     int_red_x, int_red_y, int_green_x, int_green_y,
+                     int_blue_x, int_blue_y)
+    png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y,
+                     int_red_Z, int_green_X, int_green_Y, int_green_Z,
+                     int_blue_X, int_blue_Y, int_blue_Z)
+
+    {white,red,green,blue}_{x,y}
+                     A color space encoding specified using the chromaticities
+                     of the end points and the white point.
+
+    {red,green,blue}_{X,Y,Z}
+                     A color space encoding specified using the encoding end
+                     points - the CIE tristimulus specification of the intended
+                     color of the red, green and blue channels in the PNG RGB
+                     data.  The white point is simply the sum of the three end
+                     points.
+
+    png_set_sRGB(png_ptr, info_ptr, srgb_intent);
+
+    srgb_intent    - the rendering intent
+                     (PNG_INFO_sRGB) The presence of
+                     the sRGB chunk means that the pixel
+                     data is in the sRGB color space.
+                     This chunk also implies specific
+                     values of gAMA and cHRM.  Rendering
+                     intent is the CSS-1 property that
+                     has been defined by the International
+                     Color Consortium
+                     (http://www.color.org).
+                     It can be one of
+                     PNG_sRGB_INTENT_SATURATION,
+                     PNG_sRGB_INTENT_PERCEPTUAL,
+                     PNG_sRGB_INTENT_ABSOLUTE, or
+                     PNG_sRGB_INTENT_RELATIVE.
+
+
+    png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
+       srgb_intent);
+
+    srgb_intent    - the rendering intent
+                     (PNG_INFO_sRGB) The presence of the
+                     sRGB chunk means that the pixel
+                     data is in the sRGB color space.
+                     This function also causes gAMA and
+                     cHRM chunks with the specific values
+                     that are consistent with sRGB to be
+                     written.
+
+    png_set_iCCP(png_ptr, info_ptr, name, compression_type,
+                       profile, proflen);
+
+    name             - The profile name.
+
+    compression_type - The compression type; always
+                       PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+                       You may give NULL to this argument to
+                       ignore it.
+
+    profile          - International Color Consortium color
+                       profile data. May contain NULs.
+
+    proflen          - length of profile data in bytes.
+
+    png_set_sBIT(png_ptr, info_ptr, sig_bit);
+
+    sig_bit        - the number of significant bits for
+                     (PNG_INFO_sBIT) each of the gray, red,
+                     green, and blue channels, whichever are
+                     appropriate for the given color type
+                     (png_color_16)
+
+    png_set_tRNS(png_ptr, info_ptr, trans_alpha,
+       num_trans, trans_color);
+
+    trans_alpha    - array of alpha (transparency)
+                     entries for palette (PNG_INFO_tRNS)
+
+    num_trans      - number of transparent entries
+                     (PNG_INFO_tRNS)
+
+    trans_color    - graylevel or color sample values
+                     (in order red, green, blue) of the
+                     single transparent color for
+                     non-paletted images (PNG_INFO_tRNS)
+
+    png_set_eXIf_1(png_ptr, info_ptr, num_exif, exif);
+
+    exif           - Exif profile (array of png_byte)
+                     (PNG_INFO_eXIf)
+
+    png_set_hIST(png_ptr, info_ptr, hist);
+
+    hist           - histogram of palette (array of
+                     png_uint_16) (PNG_INFO_hIST)
+
+    png_set_tIME(png_ptr, info_ptr, mod_time);
+
+    mod_time       - time image was last modified
+                     (PNG_INFO_tIME)
+
+    png_set_bKGD(png_ptr, info_ptr, background);
+
+    background     - background color (of type
+                     png_color_16p) (PNG_INFO_bKGD)
+
+    png_set_text(png_ptr, info_ptr, text_ptr, num_text);
+
+    text_ptr       - array of png_text holding image
+                     comments
+
+    text_ptr[i].compression - type of compression used
+                 on "text" PNG_TEXT_COMPRESSION_NONE
+                           PNG_TEXT_COMPRESSION_zTXt
+                           PNG_ITXT_COMPRESSION_NONE
+                           PNG_ITXT_COMPRESSION_zTXt
+    text_ptr[i].key   - keyword for comment.  Must contain
+                 1-79 characters.
+    text_ptr[i].text  - text comments for current
+                         keyword.  Can be NULL or empty.
+    text_ptr[i].text_length - length of text string,
+                 after decompression, 0 for iTXt
+    text_ptr[i].itxt_length - length of itxt string,
+                 after decompression, 0 for tEXt/zTXt
+    text_ptr[i].lang  - language of comment (NULL or
+                         empty for unknown).
+    text_ptr[i].translated_keyword  - keyword in UTF-8 (NULL
+                         or empty for unknown).
+
+    Note that the itxt_length, lang, and lang_key
+    members of the text_ptr structure only exist when the
+    library is built with iTXt chunk support.  Prior to
+    libpng-1.4.0 the library was built by default without
+    iTXt support. Also note that when iTXt is supported,
+    they contain NULL pointers when the "compression"
+    field contains PNG_TEXT_COMPRESSION_NONE or
+    PNG_TEXT_COMPRESSION_zTXt.
+
+    num_text       - number of comments
+
+    png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
+       num_spalettes);
+
+    palette_ptr    - array of png_sPLT_struct structures
+                     to be added to the list of palettes
+                     in the info structure.
+    num_spalettes  - number of palette structures to be
+                     added.
+
+    png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
+        unit_type);
+
+    offset_x  - positive offset from the left
+                     edge of the screen
+
+    offset_y  - positive offset from the top
+                     edge of the screen
+
+    unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+    png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
+        unit_type);
+
+    res_x       - pixels/unit physical resolution
+                  in x direction
+
+    res_y       - pixels/unit physical resolution
+                  in y direction
+
+    unit_type   - PNG_RESOLUTION_UNKNOWN,
+                  PNG_RESOLUTION_METER
+
+    png_set_sCAL(png_ptr, info_ptr, unit, width, height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+
+    height      - height of a pixel in physical scale units
+                  (width and height are doubles)
+
+    png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
+
+    unit        - physical scale units (an integer)
+
+    width       - width of a pixel in physical scale units
+                  expressed as a string
+
+    height      - height of a pixel in physical scale units
+                 (width and height are strings like "2.54")
+
+    png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
+       num_unknowns)
+
+    unknowns          - array of png_unknown_chunk
+                        structures holding unknown chunks
+    unknowns[i].name  - name of unknown chunk
+    unknowns[i].data  - data of unknown chunk
+    unknowns[i].size  - size of unknown chunk's data
+    unknowns[i].location - position to write chunk in file
+                           0: do not write chunk
+                           PNG_HAVE_IHDR: before PLTE
+                           PNG_HAVE_PLTE: before IDAT
+                           PNG_AFTER_IDAT: after IDAT
+
+The "location" member is set automatically according to
+what part of the output file has already been written.
+You can change its value after calling png_set_unknown_chunks()
+as demonstrated in pngtest.c.  Within each of the "locations",
+the chunks are sequenced according to their position in the
+structure (that is, the value of "i", which is the order in which
+the chunk was either read from the input file or defined with
+png_set_unknown_chunks).
+
+A quick word about text and num_text.  text is an array of png_text
+structures.  num_text is the number of valid structures in the array.
+Each png_text structure holds a language code, a keyword, a text value,
+and a compression type.
+
+The compression types have the same valid numbers as the compression
+types of the image data.  Currently, the only valid number is zero.
+However, you can store text either compressed or uncompressed, unlike
+images, which always have to be compressed.  So if you don't want the
+text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
+Because tEXt and zTXt chunks don't have a language field, if you
+specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
+any language code or translated keyword will not be written out.
+
+Until text gets around a few hundred bytes, it is not worth compressing it.
+After the text has been written out to the file, the compression type
+is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
+so that it isn't written out again at the end (in case you are calling
+png_write_end() with the same struct).
+
+The keywords that are given in the PNG Specification are:
+
+    Title            Short (one line) title or
+                     caption for image
+
+    Author           Name of image's creator
+
+    Description      Description of image (possibly long)
+
+    Copyright        Copyright notice
+
+    Creation Time    Time of original image creation
+                     (usually RFC 1123 format, see below)
+
+    Software         Software used to create the image
+
+    Disclaimer       Legal disclaimer
+
+    Warning          Warning of nature of content
+
+    Source           Device used to create the image
+
+    Comment          Miscellaneous comment; conversion
+                     from other image format
+
+The keyword-text pairs work like this.  Keywords should be short
+simple descriptions of what the comment is about.  Some typical
+keywords are found in the PNG specification, as is some recommendations
+on keywords.  You can repeat keywords in a file.  You can even write
+some text before the image and some after.  For example, you may want
+to put a description of the image before the image, but leave the
+disclaimer until after, so viewers working over modem connections
+don't have to wait for the disclaimer to go over the modem before
+they start seeing the image.  Finally, keywords should be full
+words, not abbreviations.  Keywords and text are in the ISO 8859-1
+(Latin-1) character set (a superset of regular ASCII) and can not
+contain NUL characters, and should not contain control or other
+unprintable characters.  To make the comments widely readable, stick
+with basic ASCII, and avoid machine specific character set extensions
+like the IBM-PC character set.  The keyword must be present, but
+you can leave off the text string on non-compressed pairs.
+Compressed pairs must have a text string, as only the text string
+is compressed anyway, so the compression would be meaningless.
+
+PNG supports modification time via the png_time structure.  Two
+conversion routines are provided, png_convert_from_time_t() for
+time_t and png_convert_from_struct_tm() for struct tm.  The
+time_t routine uses gmtime().  You don't have to use either of
+these, but if you wish to fill in the png_time structure directly,
+you should provide the time in universal time (GMT) if possible
+instead of your local time.  Note that the year number is the full
+year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
+that months start with 1.
+
+If you want to store the time of the original image creation, you should
+use a plain tEXt chunk with the "Creation Time" keyword.  This is
+necessary because the "creation time" of a PNG image is somewhat vague,
+depending on whether you mean the PNG file, the time the image was
+created in a non-PNG format, a still photo from which the image was
+scanned, or possibly the subject matter itself.  In order to facilitate
+machine-readable dates, it is recommended that the "Creation Time"
+tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
+although this isn't a requirement.  Unlike the tIME chunk, the
+"Creation Time" tEXt chunk is not expected to be automatically changed
+by the software.  To facilitate the use of RFC 1123 dates, a function
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
+convert from PNG time to an RFC 1123 format string.  The caller must provide
+a writeable buffer of at least 29 bytes.
+
+.SS Writing unknown chunks
+
+You can use the png_set_unknown_chunks function to queue up private chunks
+for writing.  You give it a chunk name, location, raw data, and a size.  You
+also must use png_set_keep_unknown_chunks() to ensure that libpng will
+handle them.  That's all there is to it.  The chunks will be written by the
+next following png_write_info_before_PLTE, png_write_info, or png_write_end
+function, depending upon the specified location.  Any chunks previously
+read into the info structure's unknown-chunk list will also be written out
+in a sequence that satisfies the PNG specification's ordering rules.
+
+Here is an example of writing two private chunks, prVt and miNE:
+
+    #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+    /* Set unknown chunk data */
+    png_unknown_chunk unk_chunk[2];
+    strcpy((char *) unk_chunk[0].name, "prVt";
+    unk_chunk[0].data = (unsigned char *) "PRIVATE DATA";
+    unk_chunk[0].size = strlen(unk_chunk[0].data)+1;
+    unk_chunk[0].location = PNG_HAVE_IHDR;
+    strcpy((char *) unk_chunk[1].name, "miNE";
+    unk_chunk[1].data = (unsigned char *) "MY CHUNK DATA";
+    unk_chunk[1].size = strlen(unk_chunk[0].data)+1;
+    unk_chunk[1].location = PNG_AFTER_IDAT;
+    png_set_unknown_chunks(write_ptr, write_info_ptr,
+        unk_chunk, 2);
+    /* Needed because miNE is not safe-to-copy */
+    png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
+       (png_bytep) "miNE", 1);
+    # if PNG_LIBPNG_VER < 10600
+      /* Deal with unknown chunk location bug in 1.5.x and earlier */
+      png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
+      png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
+    # endif
+    # if PNG_LIBPNG_VER < 10500
+      /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
+       * one before IDAT and another after IDAT, so don't use it; only use
+       * PNG_HAVE_IHDR location.  This call resets the location previously
+       * set by assignment and png_set_unknown_chunk_location() for chunk 1.
+       */
+      png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
+    # endif
+    #endif
+
+.SS The high-level write interface
+
+At this point there are two ways to proceed; through the high-level
+write interface, or through a sequence of low-level write operations.
+You can use the high-level interface if your image data is present
+in the info structure.  All defined output
+transformations are permitted, enabled by the following masks.
+
+    PNG_TRANSFORM_IDENTITY      No transformation
+    PNG_TRANSFORM_PACKING       Pack 1, 2 and 4-bit samples
+    PNG_TRANSFORM_PACKSWAP      Change order of packed
+                                pixels to LSB first
+    PNG_TRANSFORM_INVERT_MONO   Invert monochrome images
+    PNG_TRANSFORM_SHIFT         Normalize pixels to the
+                                sBIT depth
+    PNG_TRANSFORM_BGR           Flip RGB to BGR, RGBA
+                                to BGRA
+    PNG_TRANSFORM_SWAP_ALPHA    Flip RGBA to ARGB or GA
+                                to AG
+    PNG_TRANSFORM_INVERT_ALPHA  Change alpha from opacity
+                                to transparency
+    PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
+    PNG_TRANSFORM_STRIP_FILLER        Strip out filler
+                                      bytes (deprecated).
+    PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
+                                      filler bytes
+    PNG_TRANSFORM_STRIP_FILLER_AFTER  Strip out trailing
+                                      filler bytes
+
+If you have valid image data in the info structure (you can use
+png_set_rows() to put image data in the info structure), simply do this:
+
+    png_write_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some set of
+transformation flags.  This call is equivalent to png_write_info(),
+followed the set of transformations indicated by the transform mask,
+then png_write_image(), and finally png_write_end().
+
+(The final parameter of this call is not yet used.  Someday it might point
+to transformation parameters required by some future output transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_write_png().
+
+.SS The low-level write interface
+
+If you are going the low-level route instead, you are now ready to
+write all the file information up to the actual image data.  You do
+this with a call to png_write_info().
+
+    png_write_info(png_ptr, info_ptr);
+
+Note that there is one transformation you may need to do before
+png_write_info().  In PNG files, the alpha channel in an image is the
+level of opacity.  If your data is supplied as a level of transparency,
+you can invert the alpha channel before you write it, so that 0 is
+fully transparent and 255 (in 8-bit or paletted images) or 65535
+(in 16-bit images) is fully opaque, with
+
+    png_set_invert_alpha(png_ptr);
+
+This must appear before png_write_info() instead of later with the
+other transformations because in the case of paletted images the tRNS
+chunk data has to be inverted before the tRNS chunk is written.  If
+your image is not a paletted image, the tRNS data (which in such cases
+represents a single color to be rendered as transparent) won't need to
+be changed, and you can safely do this transformation after your
+png_write_info() call.
+
+If you need to write a private chunk that you want to appear before
+the PLTE chunk when PLTE is present, you can write the PNG info in
+two steps, and insert code to write your own chunk between them:
+
+    png_write_info_before_PLTE(png_ptr, info_ptr);
+    png_set_unknown_chunks(png_ptr, info_ptr, ...);
+    png_write_info(png_ptr, info_ptr);
+
+After you've written the file information, you can set up the library
+to handle any special transformations of the image data.  The various
+ways to transform the data will be described in the order that they
+should occur.  This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths.  Even though each transformation
+checks to see if it has data that it can do something with, you should
+make sure to only enable a transformation if it will be valid for the
+data.  For example, don't swap red and blue on grayscale data.
+
+PNG files store RGB pixels packed into 3 or 6 bytes.  This code tells
+the library to strip input data that has 4 or 8 bytes per pixel down
+to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
+bytes per pixel).
+
+    png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
+PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
+is stored XRGB or RGBX.
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit files.
+If the data is supplied at 1 pixel per byte, use this code, which will
+correctly pack the pixels into a single byte:
+
+    png_set_packing(png_ptr);
+
+PNG files reduce possible bit depths to 1, 2, 4, 8, and 16.  If your
+data is of another bit depth, you can write an sBIT chunk into the
+file so that decoders can recover the original data if desired.
+
+    /* Set the true bit depth of the image data */
+    if (color_type & PNG_COLOR_MASK_COLOR)
+    {
+       sig_bit.red = true_bit_depth;
+       sig_bit.green = true_bit_depth;
+       sig_bit.blue = true_bit_depth;
+    }
+
+    else
+    {
+       sig_bit.gray = true_bit_depth;
+    }
+
+    if (color_type & PNG_COLOR_MASK_ALPHA)
+    {
+       sig_bit.alpha = true_bit_depth;
+    }
+
+    png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+If the data is stored in the row buffer in a bit depth other than
+one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
+this will scale the values to appear to be the correct bit depth as
+is required by PNG.
+
+    png_set_shift(png_ptr, &sig_bit);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first).  This code would be used if they are
+supplied the other way (little-endian, i.e. least significant bits
+first, the way PCs store them):
+
+    if (bit_depth > 8)
+       png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+    if (bit_depth < 8)
+       png_set_packswap(png_ptr);
+
+PNG files store 3 color pixels in red, green, blue order.  This code
+would be used if they are supplied as blue, green, red:
+
+    png_set_bgr(png_ptr);
+
+PNG files describe monochrome as black being zero and white being
+one. This code would be used if the pixels are supplied with this reversed
+(black being one and white being zero):
+
+    png_set_invert_mono(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs.  This is done by setting a callback
+with
+
+    png_set_write_user_transform_fn(png_ptr,
+       write_transform_fn);
+
+You must supply the function
+
+    void write_transform_fn(png_structp png_ptr, png_row_infop
+       row_info, png_bytep data)
+
+See pngtest.c for a working example.  Your function will be called
+before any of the other transformations are processed.  If supported
+libpng also supplies an information routine that may be called from
+your callback:
+
+   png_get_current_row_number(png_ptr);
+   png_get_current_pass_number(png_ptr);
+
+This returns the current row passed to the transform.  With interlaced
+images the value returned is the row in the input sub-image image.  Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function.
+
+    png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
+
+The user_channels and user_depth parameters of this function are ignored
+when writing; you can set them to zero as shown.
+
+You can retrieve the pointer via the function png_get_user_transform_ptr().
+For example:
+
+    voidp write_user_transform_ptr =
+       png_get_user_transform_ptr(png_ptr);
+
+It is possible to have libpng flush any pending output, either manually,
+or automatically after a certain number of lines have been written.  To
+flush the output stream a single time call:
+
+    png_write_flush(png_ptr);
+
+and to have libpng flush the output stream periodically after a certain
+number of scanlines have been written, call:
+
+    png_set_flush(png_ptr, nrows);
+
+Note that the distance between rows is from the last time png_write_flush()
+was called, or the first row of the image if it has never been called.
+So if you write 50 lines, and then png_set_flush 25, it will flush the
+output on the next scanline, and every 25 lines thereafter, unless
+png_write_flush() is called before 25 more lines have been written.
+If nrows is too small (less than about 10 lines for a 640 pixel wide
+RGB image) the image compression may decrease noticeably (although this
+may be acceptable for real-time applications).  Infrequent flushing will
+only degrade the compression performance by a few percent over images
+that do not use flushing.
+
+.SS Writing the image data
+
+That's it for the transformations.  Now you can write the image data.
+The simplest way to do this is in one function call.  If you have the
+whole image in memory, you can just call png_write_image() and libpng
+will write the image.  You will need to pass in an array of pointers to
+each row.  This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() or call this function multiple
+times, or any of that other stuff necessary with png_write_rows().
+
+    png_write_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+    png_byte *row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to write the whole image at once, you can
+use png_write_rows() instead.  If the file is not interlaced,
+this is simple:
+
+    png_write_rows(png_ptr, row_pointers,
+       number_of_rows);
+
+row_pointers is the same as in the png_write_image() call.
+
+If you are just writing one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+    png_bytep row_pointer = row;
+
+    png_write_row(png_ptr, row_pointer);
+
+When the file is interlaced, things can get a good deal more complicated.
+The only currently (as of the PNG Specification version 1.2, dated July
+1999) defined interlacing scheme for PNG files is the "Adam7" interlace
+scheme, that breaks down an image into seven smaller images of varying
+size.  libpng will build these images for you, or you can do them
+yourself.  If you want to build them yourself, see the PNG specification
+for details of which pixels to write when.
+
+If you don't want libpng to handle the interlacing details, just
+use png_set_interlace_handling() and call png_write_rows() the
+correct number of times to write all the sub-images
+(png_set_interlace_handling() returns the number of sub-images.)
+
+If you want libpng to build the sub-images, call this before you start
+writing any rows:
+
+    number_of_passes = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed.  Currently, this is seven,
+but may change if another interlace type is added.
+
+Then write the complete image number_of_passes times.
+
+    png_write_rows(png_ptr, row_pointers, number_of_rows);
+
+Think carefully before you write an interlaced image.  Typically code that
+reads such images reads all the image data into memory, uncompressed, before
+doing any processing.  Only code that can display an image on the fly can
+take advantage of the interlacing and even then the image has to be exactly
+the correct size for the output device, because scaling an image requires
+adjacent pixels and these are not available until all the passes have been
+read.
+
+If you do write an interlaced image you will hardly ever need to handle
+the interlacing yourself.  Call png_set_interlace_handling() and use the
+approach described above.
+
+The only time it is conceivable that you will really need to write an
+interlaced image pass-by-pass is when you have read one pass by pass and
+made some pixel-by-pixel transformation to it, as described in the read
+code above.  In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
+to determine the size of each sub-image in turn and simply write the rows
+you obtained from the read code.
+
+.SS Finishing a sequential write
+
+After you are finished writing the image, you should finish writing
+the file.  If you are interested in writing comments or time, you should
+pass an appropriately filled png_info pointer.  If you are not interested,
+you can pass NULL.
+
+    png_write_end(png_ptr, info_ptr);
+
+When you are done, you can free all memory used by libpng like this:
+
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+    png_free_data(png_ptr, info_ptr, mask, seq)
+
+    mask  - identifies data to be freed, a mask
+            containing the bitwise OR of one or
+            more of
+              PNG_FREE_PLTE, PNG_FREE_TRNS,
+              PNG_FREE_HIST, PNG_FREE_ICCP,
+              PNG_FREE_PCAL, PNG_FREE_ROWS,
+              PNG_FREE_SCAL, PNG_FREE_SPLT,
+              PNG_FREE_TEXT, PNG_FREE_UNKN,
+            or simply PNG_FREE_ALL
+
+    seq   - sequence number of item to be freed
+            (\-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user  and not by libpng,  and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed.  If "seq" is not \-1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+If you allocated data such as a palette that you passed in to libpng
+with png_set_*, you must not free it until just before the call to
+png_destroy_write_struct().
+
+The default behavior is only to free data that was allocated internally
+by libpng.  This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+    png_data_freer(png_ptr, info_ptr, freer, mask)
+
+    freer  - one of
+               PNG_DESTROY_WILL_FREE_DATA
+               PNG_SET_WILL_FREE_DATA
+               PNG_USER_WILL_FREE_DATA
+
+    mask   - which data elements are affected
+             same choices as in png_free_data()
+
+For example, to transfer responsibility for some data from a read structure
+to a write structure, you could use
+
+    png_data_freer(read_ptr, read_info_ptr,
+       PNG_USER_WILL_FREE_DATA,
+       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+    png_data_freer(write_ptr, write_info_ptr,
+       PNG_DESTROY_WILL_FREE_DATA,
+       PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+thereby briefly reassigning responsibility for freeing to the user but
+immediately afterwards reassigning it once more to the write_destroy
+function.  Having done this, it would then be safe to destroy the read
+structure and continue to use the PLTE, tRNS, and hIST data in the write
+structure.
+
+This function only affects data that has already been allocated.
+You can call this function before calling after the png_set_*() functions
+to control whether the user or png_destroy_*() is supposed to free the data.
+When the user assumes responsibility for libpng-allocated data, the
+application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key.  Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+For a more compact example of writing a PNG image, see the file example.c.
+
+.SH V. Simplified API
+
+The simplified API, which became available in libpng-1.6.0, hides the details
+of both libpng and the PNG file format itself.
+It allows PNG files to be read into a very limited number of
+in-memory bitmap formats or to be written from the same formats.  If these
+formats do not accommodate your needs then you can, and should, use the more
+sophisticated APIs above - these support a wide variety of in-memory formats
+and a wide variety of sophisticated transformations to those formats as well
+as a wide variety of APIs to manipulate ancillary information.
+
+To read a PNG file using the simplified API:
+
+  1) Declare a 'png_image' structure (see below) on the stack, set the
+     version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
+     (this is REQUIRED, your program may crash if you don't do it.)
+
+  2) Call the appropriate png_image_begin_read... function.
+
+  3) Set the png_image 'format' member to the required sample format.
+
+  4) Allocate a buffer for the image and, if required, the color-map.
+
+  5) Call png_image_finish_read to read the image and, if required, the
+     color-map into your buffers.
+
+There are no restrictions on the format of the PNG input itself; all valid
+color types, bit depths, and interlace methods are acceptable, and the
+input image is transformed as necessary to the requested in-memory format
+during the png_image_finish_read() step.  The only caveat is that if you
+request a color-mapped image from a PNG that is full-color or makes
+complex use of an alpha channel the transformation is extremely lossy and the
+result may look terrible.
+
+To write a PNG file using the simplified API:
+
+  1) Declare a 'png_image' structure on the stack and memset()
+     it to all zero.
+
+  2) Initialize the members of the structure that describe the
+     image, setting the 'format' member to the format of the
+     image samples.
+
+  3) Call the appropriate png_image_write... function with a
+     pointer to the image and, if necessary, the color-map to write
+     the PNG data.
+
+png_image is a structure that describes the in-memory format of an image
+when it is being read or defines the in-memory format of an image that you
+need to write.  The "png_image" structure contains the following members:
+
+   png_controlp opaque  Initialize to NULL, free with png_image_free
+   png_uint_32  version Set to PNG_IMAGE_VERSION
+   png_uint_32  width   Image width in pixels (columns)
+   png_uint_32  height  Image height in pixels (rows)
+   png_uint_32  format  Image format as defined below
+   png_uint_32  flags   A bit mask containing informational flags
+   png_uint_32  colormap_entries; Number of entries in the color-map
+   png_uint_32  warning_or_error;
+   char         message[64];
+
+In the event of an error or warning the "warning_or_error"
+field will be set to a non-zero value and the 'message' field will contain
+a '\0' terminated string with the libpng error or warning message.  If both
+warnings and an error were encountered, only the error is recorded.  If there
+are multiple warnings, only the first one is recorded.
+
+The upper 30 bits of the "warning_or_error" value are reserved; the low two
+bits contain a two bit code such that a value more than 1 indicates a failure
+in the API just called:
+
+   0 - no warning or error
+   1 - warning
+   2 - error
+   3 - error preceded by warning
+
+The pixels (samples) of the image have one to four channels whose components
+have original values in the range 0 to 1.0:
+
+  1: A single gray or luminance channel (G).
+  2: A gray/luminance channel and an alpha channel (GA).
+  3: Three red, green, blue color channels (RGB).
+  4: Three color channels and an alpha channel (RGBA).
+
+The channels are encoded in one of two ways:
+
+  a) As a small integer, value 0..255, contained in a single byte.  For the
+alpha channel the original value is simply value/255.  For the color or
+luminance channels the value is encoded according to the sRGB specification
+and matches the 8-bit format expected by typical display devices.
+
+The color/gray channels are not scaled (pre-multiplied) by the alpha
+channel and are suitable for passing to color management software.
+
+  b) As a value in the range 0..65535, contained in a 2-byte integer, in
+the native byte order of the platform on which the application is running.
+All channels can be converted to the original value by dividing by 65535; all
+channels are linear.  Color channels use the RGB encoding (RGB end-points) of
+the sRGB specification.  This encoding is identified by the
+PNG_FORMAT_FLAG_LINEAR flag below.
+
+When the simplified API needs to convert between sRGB and linear colorspaces,
+the actual sRGB transfer curve defined in the sRGB specification (see the
+article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+approximation used elsewhere in libpng.
+
+When an alpha channel is present it is expected to denote pixel coverage
+of the color or luminance channels and is returned as an associated alpha
+channel: the color/gray channels are scaled (pre-multiplied) by the alpha
+value.
+
+The samples are either contained directly in the image data, between 1 and 8
+bytes per pixel according to the encoding, or are held in a color-map indexed
+by bytes in the image data.  In the case of a color-map the color-map entries
+are individual samples, encoded as above, and the image data has one byte per
+pixel to select the relevant sample from the color-map.
+
+PNG_FORMAT_*
+
+The #defines to be used in png_image::format.  Each #define identifies a
+particular layout of channel data and, if present, alpha values.  There are
+separate defines for each of the two component encodings.
+
+A format is built up using single bit flag values.  All combinations are
+valid.  Formats can be built up from the flag values or you can use one of
+the predefined values below.  When testing formats always use the FORMAT_FLAG
+macros to test for individual features - future versions of the library may
+add new flags.
+
+When reading or writing color-mapped images the format should be set to the
+format of the entries in the color-map then png_image_{read,write}_colormap
+called to read or write the color-map and set the format correctly for the
+image data.  Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
+
+NOTE: libpng can be built with particular features disabled. If you see
+compiler errors because the definition of one of the following flags has been
+compiled out it is because libpng does not have the required support.  It is
+possible, however, for the libpng configuration to enable the format on just
+read or just write; in that case you may see an error at run time.
+You can guard against this by checking for the definition of the
+appropriate "_SUPPORTED" macro, one of:
+
+   PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
+
+   PNG_FORMAT_FLAG_ALPHA    format with an alpha channel
+   PNG_FORMAT_FLAG_COLOR    color format: otherwise grayscale
+   PNG_FORMAT_FLAG_LINEAR   2-byte channels else 1-byte
+   PNG_FORMAT_FLAG_COLORMAP image data is color-mapped
+   PNG_FORMAT_FLAG_BGR      BGR colors, else order is RGB
+   PNG_FORMAT_FLAG_AFIRST   alpha channel comes first
+
+Supported formats are as follows.  Future versions of libpng may support more
+formats; for compatibility with older versions simply check if the format
+macro is defined using #ifdef.  These defines describe the in-memory layout
+of the components of the pixels of the image.
+
+First the single byte (sRGB) formats:
+
+   PNG_FORMAT_GRAY
+   PNG_FORMAT_GA
+   PNG_FORMAT_AG
+   PNG_FORMAT_RGB
+   PNG_FORMAT_BGR
+   PNG_FORMAT_RGBA
+   PNG_FORMAT_ARGB
+   PNG_FORMAT_BGRA
+   PNG_FORMAT_ABGR
+
+Then the linear 2-byte formats.  When naming these "Y" is used to
+indicate a luminance (gray) channel.  The component order within the pixel
+is always the same - there is no provision for swapping the order of the
+components in the linear format.  The components are 16-bit integers in
+the native byte order for your platform, and there is no provision for
+swapping the bytes to a different endian condition.
+
+   PNG_FORMAT_LINEAR_Y
+   PNG_FORMAT_LINEAR_Y_ALPHA
+   PNG_FORMAT_LINEAR_RGB
+   PNG_FORMAT_LINEAR_RGB_ALPHA
+
+With color-mapped formats the image data is one byte for each pixel. The byte
+is an index into the color-map which is formatted as above.  To obtain a
+color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
+to one of the above definitions, or you can use one of the definitions below.
+
+   PNG_FORMAT_RGB_COLORMAP
+   PNG_FORMAT_BGR_COLORMAP
+   PNG_FORMAT_RGBA_COLORMAP
+   PNG_FORMAT_ARGB_COLORMAP
+   PNG_FORMAT_BGRA_COLORMAP
+   PNG_FORMAT_ABGR_COLORMAP
+
+PNG_IMAGE macros
+
+These are convenience macros to derive information from a png_image
+structure.  The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
+actual image sample values - either the entries in the color-map or the
+pixels in the image.  The PNG_IMAGE_PIXEL_ macros return corresponding values
+for the pixels and will always return 1 for color-mapped formats.  The
+remaining macros return information about the rows in the image and the
+complete image.
+
+NOTE: All the macros that take a png_image::format parameter are compile time
+constants if the format parameter is, itself, a constant.  Therefore these
+macros can be used in array declarations and case labels where required.
+Similarly the macros are also pre-processor constants (sizeof is not used) so
+they can be used in #if tests.
+
+  PNG_IMAGE_SAMPLE_CHANNELS(fmt)
+    Returns the total number of channels in a given format: 1..4
+
+  PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)
+    Returns the size in bytes of a single component of a pixel or color-map
+    entry (as appropriate) in the image: 1 or 2.
+
+  PNG_IMAGE_SAMPLE_SIZE(fmt)
+    This is the size of the sample data for one sample.  If the image is
+    color-mapped it is the size of one color-map entry (and image pixels are
+    one byte in size), otherwise it is the size of one image pixel.
+
+  PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)
+    The maximum size of the color-map required by the format expressed in a
+    count of components.  This can be used to compile-time allocate a
+    color-map:
+
+    png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
+
+    png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
+
+    Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+    information from one of the png_image_begin_read_ APIs and dynamically
+    allocate the required memory.
+
+  PNG_IMAGE_COLORMAP_SIZE(fmt)
+   The size of the color-map required by the format; this is the size of the
+   color-map buffer passed to the png_image_{read,write}_colormap APIs. It is
+   a fixed number determined by the format so can easily be allocated on the
+   stack if necessary.
+
+Corresponding information about the pixels
+
+  PNG_IMAGE_PIXEL_CHANNELS(fmt)
+   The number of separate channels (components) in a pixel; 1 for a
+   color-mapped image.
+
+  PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
+   The size, in bytes, of each component in a pixel; 1 for a color-mapped
+   image.
+
+  PNG_IMAGE_PIXEL_SIZE(fmt)
+   The size, in bytes, of a complete pixel; 1 for a color-mapped image.
+
+Information about the whole row, or whole image
+
+  PNG_IMAGE_ROW_STRIDE(image)
+   Returns the total number of components in a single row of the image; this
+   is the minimum 'row stride', the minimum count of components between each
+   row.  For a color-mapped image this is the minimum number of bytes in a
+   row.
+
+   If you need the stride measured in bytes, row_stride_bytes is
+   PNG_IMAGE_ROW_STRIDE(image) * PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)
+   plus any padding bytes that your application might need, for example
+   to start the next row on a 4-byte boundary.
+
+  PNG_IMAGE_BUFFER_SIZE(image, row_stride)
+   Return the size, in bytes, of an image buffer given a png_image and a row
+   stride - the number of components to leave space for in each row.
+
+  PNG_IMAGE_SIZE(image)
+   Return the size, in bytes, of the image in memory given just a png_image;
+   the row stride is the minimum stride required for the image.
+
+  PNG_IMAGE_COLORMAP_SIZE(image)
+   Return the size, in bytes, of the color-map of this image.  If the image
+   format is not a color-map format this will return a size sufficient for
+   256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
+   you don't want to allocate a color-map in this case.
+
+PNG_IMAGE_FLAG_*
+
+Flags containing additional information about the image are held in
+the 'flags' field of png_image.
+
+  PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01
+    This indicates that the RGB values of the in-memory bitmap do not
+    correspond to the red, green and blue end-points defined by sRGB.
+
+  PNG_IMAGE_FLAG_FAST == 0x02
+   On write emphasise speed over compression; the resultant PNG file will be
+   larger but will be produced significantly faster, particular for large
+   images.  Do not use this option for images which will be distributed, only
+   used it when producing intermediate files that will be read back in
+   repeatedly.  For a typical 24-bit image the option will double the read
+   speed at the cost of increasing the image size by 25%, however for many
+   more compressible images the PNG file can be 10 times larger with only a
+   slight speed gain.
+
+  PNG_IMAGE_FLAG_16BIT_sRGB == 0x04
+    On read if the image is a 16-bit per component image and there is no gAMA
+    or sRGB chunk assume that the components are sRGB encoded.  Notice that
+    images output by the simplified API always have gamma information; setting
+    this flag only affects the interpretation of 16-bit images from an
+    external source.  It is recommended that the application expose this flag
+    to the user; the user can normally easily recognize the difference between
+    linear and sRGB encoding.  This flag has no effect on write - the data
+    passed to the write APIs must have the correct encoding (as defined
+    above.)
+
+    If the flag is not set (the default) input 16-bit per component data is
+    assumed to be linear.
+
+    NOTE: the flag can only be set after the png_image_begin_read_ call,
+    because that call initializes the 'flags' field.
+
+READ APIs
+
+   The png_image passed to the read APIs must have been initialized by setting
+   the png_controlp field 'opaque' to NULL (or, better, memset the whole thing.)
+
+   int png_image_begin_read_from_file( png_imagep image,
+     const char *file_name)
+
+     The named file is opened for read and the image header
+     is filled in from the PNG header in the file.
+
+   int png_image_begin_read_from_stdio (png_imagep image,
+     FILE* file)
+
+      The PNG header is read from the stdio FILE object.
+
+   int png_image_begin_read_from_memory(png_imagep image,
+      png_const_voidp memory, size_t size)
+
+      The PNG header is read from the given memory buffer.
+
+   int png_image_finish_read(png_imagep image,
+      png_colorp background, void *buffer,
+      png_int_32 row_stride, void *colormap));
+
+      Finish reading the image into the supplied buffer and
+      clean up the png_image structure.
+
+      row_stride is the step, in png_byte or png_uint_16 units
+      as appropriate, between adjacent rows.  A positive stride
+      indicates that the top-most row is first in the buffer -
+      the normal top-down arrangement.  A negative stride
+      indicates that the bottom-most row is first in the buffer.
+
+      background need only be supplied if an alpha channel must
+      be removed from a png_byte format and the removal is to be
+      done by compositing on a solid color; otherwise it may be
+      NULL and any composition will be done directly onto the
+      buffer.  The value is an sRGB color to use for the
+      background, for grayscale output the green channel is used.
+
+      For linear output removing the alpha channel is always done
+      by compositing on black.
+
+   void png_image_free(png_imagep image)
+
+      Free any data allocated by libpng in image->opaque,
+      setting the pointer to NULL.  May be called at any time
+      after the structure is initialized.
+
+When the simplified API needs to convert between sRGB and linear colorspaces,
+the actual sRGB transfer curve defined in the sRGB specification (see the
+article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+approximation used elsewhere in libpng.
+
+WRITE APIS
+
+For write you must initialize a png_image structure to describe the image to
+be written:
+
+   version: must be set to PNG_IMAGE_VERSION
+   opaque: must be initialized to NULL
+   width: image width in pixels
+   height: image height in rows
+   format: the format of the data you wish to write
+   flags: set to 0 unless one of the defined flags applies; set
+      PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images
+      where the RGB values do not correspond to the colors in sRGB.
+   colormap_entries: set to the number of entries in the color-map (0 to 256)
+
+   int png_image_write_to_file, (png_imagep image,
+      const char *file, int convert_to_8bit, const void *buffer,
+      png_int_32 row_stride, const void *colormap));
+
+      Write the image to the named file.
+
+   int png_image_write_to_memory (png_imagep image, void *memory,
+      png_alloc_size_t * PNG_RESTRICT memory_bytes,
+      int convert_to_8_bit, const void *buffer, ptrdiff_t row_stride,
+      const void *colormap));
+
+      Write the image to memory.
+
+   int png_image_write_to_stdio(png_imagep image, FILE *file,
+      int convert_to_8_bit, const void *buffer,
+      png_int_32 row_stride, const void *colormap)
+
+      Write the image to the given (FILE*).
+
+With all write APIs if image is in one of the linear formats with
+(png_uint_16) data then setting convert_to_8_bit will cause the output to be
+a (png_byte) PNG gamma encoded according to the sRGB specification, otherwise
+a 16-bit linear encoded PNG file is written.
+
+With all APIs row_stride is handled as in the read APIs - it is the spacing
+from one row to the next in component sized units (float) and if negative
+indicates a bottom-up row layout in the buffer.  If you pass zero, libpng will
+calculate the row_stride for you from the width and number of channels.
+
+Note that the write API does not support interlacing, sub-8-bit pixels,
+indexed (paletted) images, or most ancillary chunks.
+
+.SH VI. Modifying/Customizing libpng
+
+There are two issues here.  The first is changing how libpng does
+standard things like memory allocation, input/output, and error handling.
+The second deals with more complicated things like adding new chunks,
+adding new transformations, and generally changing how libpng works.
+Both of those are compile-time issues; that is, they are generally
+determined at the time the code is written, and there is rarely a need
+to provide the user with a means of changing them.
+
+Memory allocation, input/output, and error handling
+
+All of the memory allocation, input/output, and error handling in libpng
+goes through callbacks that are user-settable.  The default routines are
+in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively.  To change
+these functions, call the appropriate png_set_*_fn() function.
+
+Memory allocation is done through the functions png_malloc(), png_calloc(),
+and png_free().  The png_malloc() and png_free() functions currently just
+call the standard C functions and png_calloc() calls png_malloc() and then
+clears the newly allocated memory to zero; note that png_calloc(png_ptr, size)
+is not the same as the calloc(number, size) function provided by stdlib.h.
+There is limited support for certain systems with segmented memory
+architectures and the types of pointers declared by png.h match this; you
+will have to use appropriate pointers in your application.  If you prefer
+to use a different method of allocating and freeing data, you can use
+png_create_read_struct_2() or png_create_write_struct_2() to register your
+own functions as described above.  These functions also provide a void
+pointer that can be retrieved via
+
+    mem_ptr = png_get_mem_ptr(png_ptr);
+
+Your replacement memory functions must have prototypes as follows:
+
+    png_voidp malloc_fn(png_structp png_ptr,
+       png_alloc_size_t size);
+
+    void free_fn(png_structp png_ptr, png_voidp ptr);
+
+Your malloc_fn() must return NULL in case of failure.  The png_malloc()
+function will normally call png_error() if it receives a NULL from the
+system memory allocator or from your replacement malloc_fn().
+
+Your free_fn() will never be called with a NULL ptr, since libpng's
+png_free() checks for NULL before calling free_fn().
+
+Input/Output in libpng is done through png_read() and png_write(),
+which currently just call fread() and fwrite().  The FILE * is stored in
+png_struct and is initialized via png_init_io().  If you wish to change
+the method of I/O, the library supplies callbacks that you can set
+through the function png_set_read_fn() and png_set_write_fn() at run
+time, instead of calling the png_init_io() function.  These functions
+also provide a void pointer that can be retrieved via the function
+png_get_io_ptr().  For example:
+
+    png_set_read_fn(png_structp read_ptr,
+        voidp read_io_ptr, png_rw_ptr read_data_fn)
+
+    png_set_write_fn(png_structp write_ptr,
+        voidp write_io_ptr, png_rw_ptr write_data_fn,
+        png_flush_ptr output_flush_fn);
+
+    voidp read_io_ptr = png_get_io_ptr(read_ptr);
+    voidp write_io_ptr = png_get_io_ptr(write_ptr);
+
+The replacement I/O functions must have prototypes as follows:
+
+    void user_read_data(png_structp png_ptr,
+        png_bytep data, size_t length);
+
+    void user_write_data(png_structp png_ptr,
+        png_bytep data, size_t length);
+
+    void user_flush_data(png_structp png_ptr);
+
+The user_read_data() function is responsible for detecting and
+handling end-of-data errors.
+
+Supplying NULL for the read, write, or flush functions sets them back
+to using the default C stream functions, which expect the io_ptr to
+point to a standard *FILE structure.  It is probably a mistake
+to use NULL for one of write_data_fn and output_flush_fn but not both
+of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
+It is an error to read from a write stream, and vice versa.
+
+Error handling in libpng is done through png_error() and png_warning().
+Errors handled through png_error() are fatal, meaning that png_error()
+should never return to its caller.  Currently, this is handled via
+setjmp() and longjmp() (unless you have compiled libpng with
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
+but you could change this to do things like exit() if you should wish,
+as long as your function does not return.
+
+On non-fatal errors, png_warning() is called
+to print a warning message, and then control returns to the calling code.
+By default png_error() and png_warning() print a message on stderr via
+fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
+(because you don't want the messages) or PNG_NO_STDIO defined (because
+fprintf() isn't available).  If you wish to change the behavior of the error
+functions, you will need to set up your own message callbacks.  These
+functions are normally supplied at the time that the png_struct is created.
+It is also possible to redirect errors and warnings to your own replacement
+functions after png_create_*_struct() has been called by calling:
+
+    png_set_error_fn(png_structp png_ptr,
+        png_voidp error_ptr, png_error_ptr error_fn,
+        png_error_ptr warning_fn);
+
+If NULL is supplied for either error_fn or warning_fn, then the libpng
+default function will be used, calling fprintf() and/or longjmp() if a
+problem is encountered.  The replacement error functions should have
+parameters as follows:
+
+    void user_error_fn(png_structp png_ptr,
+        png_const_charp error_msg);
+
+    void user_warning_fn(png_structp png_ptr,
+        png_const_charp warning_msg);
+
+Then, within your user_error_fn or user_warning_fn, you can retrieve
+the error_ptr if you need it, by calling
+
+    png_voidp error_ptr = png_get_error_ptr(png_ptr);
+
+The motivation behind using setjmp() and longjmp() is the C++ throw and
+catch exception handling methods.  This makes the code much easier to write,
+as there is no need to check every return code of every function call.
+However, there are some uncertainties about the status of local variables
+after a longjmp, so the user may want to be careful about doing anything
+after setjmp returns non-zero besides returning itself.  Consult your
+compiler documentation for more details.  For an alternative approach, you
+may wish to use the "cexcept" facility (see https://cexcept.sourceforge.io/),
+which is illustrated in pngvalid.c and in contrib/visupng.
+
+Beginning in libpng-1.4.0, the png_set_benign_errors() API became available.
+You can use this to handle certain errors (normally handled as errors)
+as warnings.
+
+    png_set_benign_errors (png_ptr, int allowed);
+
+    allowed: 0: treat png_benign_error() as an error.
+             1: treat png_benign_error() as a warning.
+
+As of libpng-1.6.0, the default condition is to treat benign errors as
+warnings while reading and as errors while writing.
+
+.SS Custom chunks
+
+If you need to read or write custom chunks, you may need to get deeper
+into the libpng code.  The library now has mechanisms for storing
+and writing chunks of unknown type; you can even declare callbacks
+for custom chunks.  However, this may not be good enough if the
+library code itself needs to know about interactions between your
+chunk and existing `intrinsic' chunks.
+
+If you need to write a new intrinsic chunk, first read the PNG
+specification. Acquire a first level of understanding of how it works.
+Pay particular attention to the sections that describe chunk names,
+and look at how other chunks were designed, so you can do things
+similarly.  Second, check out the sections of libpng that read and
+write chunks.  Try to find a chunk that is similar to yours and use
+it as a template.  More details can be found in the comments inside
+the code.  It is best to handle private or unknown chunks in a generic method,
+via callback functions, instead of by modifying libpng functions. This
+is illustrated in pngtest.c, which uses a callback function to handle a
+private "vpAg" chunk and the new "sTER" chunk, which are both unknown to
+libpng.
+
+If you wish to write your own transformation for the data, look through
+the part of the code that does the transformations, and check out some of
+the simpler ones to get an idea of how they work.  Try to find a similar
+transformation to the one you want to add and copy off of it.  More details
+can be found in the comments inside the code itself.
+
+.SS Configuring for gui/windowing platforms:
+
+You will need to write new error and warning functions that use the GUI
+interface, as described previously, and set them to be the error and
+warning functions at the time that png_create_*_struct() is called,
+in order to have them available during the structure initialization.
+They can be changed later via png_set_error_fn().  On some compilers,
+you may also have to change the memory allocators (png_malloc, etc.).
+
+.SS Configuring zlib:
+
+There are special functions to configure the compression.  Perhaps the
+most useful one changes the compression level, which currently uses
+input compression values in the range 0 - 9.  The library normally
+uses the default compression level (Z_DEFAULT_COMPRESSION = 6).  Tests
+have shown that for a large majority of images, compression values in
+the range 3-6 compress nearly as well as higher levels, and do so much
+faster.  For online applications it may be desirable to have maximum speed
+(Z_BEST_SPEED = 1).  With versions of zlib after v0.99, you can also
+specify no compression (Z_NO_COMPRESSION = 0), but this would create
+files larger than just storing the raw bitmap.  You can specify the
+compression level by calling:
+
+    #include zlib.h
+    png_set_compression_level(png_ptr, level);
+
+Another useful one is to reduce the memory level used by the library.
+The memory level defaults to 8, but it can be lowered if you are
+short on memory (running DOS, for example, where you only have 640K).
+Note that the memory level does have an effect on compression; among
+other things, lower levels will result in sections of incompressible
+data being emitted in smaller stored blocks, with a correspondingly
+larger relative overhead of up to 15% in the worst case.
+
+    #include zlib.h
+    png_set_compression_mem_level(png_ptr, level);
+
+The other functions are for configuring zlib.  They are not recommended
+for normal use and may result in writing an invalid PNG file.  See
+zlib.h for more information on what these mean.
+
+    #include zlib.h
+    png_set_compression_strategy(png_ptr,
+        strategy);
+
+    png_set_compression_window_bits(png_ptr,
+        window_bits);
+
+    png_set_compression_method(png_ptr, method);
+
+This controls the size of the IDAT chunks (default 8192):
+
+    png_set_compression_buffer_size(png_ptr, size);
+
+As of libpng version 1.5.4, additional APIs became
+available to set these separately for non-IDAT
+compressed chunks such as zTXt, iTXt, and iCCP:
+
+    #include zlib.h
+    #if PNG_LIBPNG_VER >= 10504
+    png_set_text_compression_level(png_ptr, level);
+
+    png_set_text_compression_mem_level(png_ptr, level);
+
+    png_set_text_compression_strategy(png_ptr,
+        strategy);
+
+    png_set_text_compression_window_bits(png_ptr,
+        window_bits);
+
+    png_set_text_compression_method(png_ptr, method);
+    #endif
+
+.SS Controlling row filtering
+
+If you want to control whether libpng uses filtering or not, which
+filters are used, and how it goes about picking row filters, you
+can call one of these functions.  The selection and configuration
+of row filters can have a significant impact on the size and
+encoding speed and a somewhat lesser impact on the decoding speed
+of an image.  Filtering is enabled by default for RGB and grayscale
+images (with and without alpha), but not for paletted images nor
+for any images with bit depths less than 8 bits/pixel.
+
+The 'method' parameter sets the main filtering method, which is
+currently only '0' in the PNG 1.2 specification.  The 'filters'
+parameter sets which filter(s), if any, should be used for each
+scanline.  Possible values are PNG_ALL_FILTERS, PNG_NO_FILTERS,
+or PNG_FAST_FILTERS to turn filtering on and off, or to turn on
+just the fast-decoding subset of filters, respectively.
+
+Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
+PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
+ORed together with '|' to specify one or more filters to use.
+These filters are described in more detail in the PNG specification.
+If you intend to change the filter type during the course of writing
+the image, you should start with flags set for all of the filters
+you intend to use so that libpng can initialize its internal
+structures appropriately for all of the filter types.  (Note that this
+means the first row must always be adaptively filtered, because libpng
+currently does not allocate the filter buffers until png_write_row()
+is called for the first time.)
+
+    filters = PNG_NO_FILTERS;
+    filters = PNG_ALL_FILTERS;
+    filters = PNG_FAST_FILTERS;
+
+    or
+
+    filters = PNG_FILTER_NONE | PNG_FILTER_SUB |
+              PNG_FILTER_UP | PNG_FILTER_AVG |
+              PNG_FILTER_PAETH;
+
+    png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
+       filters);
+
+              The second parameter can also be
+              PNG_INTRAPIXEL_DIFFERENCING if you are
+              writing a PNG to be embedded in a MNG
+              datastream.  This parameter must be the
+              same as the value of filter_method used
+              in png_set_IHDR().
+
+.SS Requesting debug printout
+
+The macro definition PNG_DEBUG can be used to request debugging
+printout.  Set it to an integer value in the range 0 to 3.  Higher
+numbers result in increasing amounts of debugging information.  The
+information is printed to the "stderr" file, unless another file
+name is specified in the PNG_DEBUG_FILE macro definition.
+
+When PNG_DEBUG > 0, the following functions (macros) become available:
+
+   png_debug(level, message)
+   png_debug1(level, message, p1)
+   png_debug2(level, message, p1, p2)
+
+in which "level" is compared to PNG_DEBUG to decide whether to print
+the message, "message" is the formatted string to be printed,
+and p1 and p2 are parameters that are to be embedded in the string
+according to printf-style formatting directives.  For example,
+
+   png_debug1(2, "foo=%d", foo);
+
+is expanded to
+
+   if (PNG_DEBUG > 2)
+      fprintf(PNG_DEBUG_FILE, "foo=%d\en", foo);
+
+When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
+can still use PNG_DEBUG to control your own debugging:
+
+   #ifdef PNG_DEBUG
+       fprintf(stderr, ...);
+   #endif
+
+When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
+having level = 0 will be printed.  There aren't any such statements in
+this version of libpng, but if you insert some they will be printed.
+
+.SH VII. MNG support
+
+The MNG specification (available at http://www.libpng.org/pub/mng) allows
+certain extensions to PNG for PNG images that are embedded in MNG datastreams.
+Libpng can support some of these extensions.  To enable them, use the
+png_permit_mng_features() function:
+
+   feature_set = png_permit_mng_features(png_ptr, mask)
+
+   mask is a png_uint_32 containing the bitwise OR of the
+        features you want to enable.  These include
+        PNG_FLAG_MNG_EMPTY_PLTE
+        PNG_FLAG_MNG_FILTER_64
+        PNG_ALL_MNG_FEATURES
+
+   feature_set is a png_uint_32 that is the bitwise AND of
+      your mask with the set of MNG features that is
+      supported by the version of libpng that you are using.
+
+It is an error to use this function when reading or writing a standalone
+PNG file with the PNG 8-byte signature.  The PNG datastream must be wrapped
+in a MNG datastream.  As a minimum, it must have the MNG 8-byte signature
+and the MHDR and MEND chunks.  Libpng does not provide support for these
+or any other MNG chunks; your application must provide its own support for
+them.  You may wish to consider using libmng (available at
+https://www.libmng.com/) instead.
+
+.SH VIII. Changes to Libpng from version 0.88
+
+It should be noted that versions of libpng later than 0.96 are not
+distributed by the original libpng author, Guy Schalnat, nor by
+Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
+distributed versions 0.89 through 0.96, but rather by another member
+of the original PNG Group, Glenn Randers-Pehrson.  Guy and Andreas are
+still alive and well, but they have moved on to other things.
+
+The old libpng functions png_read_init(), png_write_init(),
+png_info_init(), png_read_destroy(), and png_write_destroy() have been
+moved to PNG_INTERNAL in version 0.95 to discourage their use.  These
+functions will be removed from libpng version 1.4.0.
+
+The preferred method of creating and initializing the libpng structures is
+via the png_create_read_struct(), png_create_write_struct(), and
+png_create_info_struct() because they isolate the size of the structures
+from the application, allow version error checking, and also allow the
+use of custom error handling routines during the initialization, which
+the old functions do not.  The functions png_read_destroy() and
+png_write_destroy() do not actually free the memory that libpng
+allocated for these structs, but just reset the data structures, so they
+can be used instead of png_destroy_read_struct() and
+png_destroy_write_struct() if you feel there is too much system overhead
+allocating and freeing the png_struct for each image read.
+
+Setting the error callbacks via png_set_message_fn() before
+png_read_init() as was suggested in libpng-0.88 is no longer supported
+because this caused applications that do not use custom error functions
+to fail if the png_ptr was not initialized to zero.  It is still possible
+to set the error callbacks AFTER png_read_init(), or to change them with
+png_set_error_fn(), which is essentially the same function, but with a new
+name to force compilation errors with applications that try to use the old
+method.
+
+Support for the sCAL, iCCP, iTXt, and sPLT chunks was added at libpng-1.0.6;
+however, iTXt support was not enabled by default.
+
+Starting with version 1.0.7, you can find out which version of the library
+you are using at run-time:
+
+   png_uint_32 libpng_vn = png_access_version_number();
+
+The number libpng_vn is constructed from the major version, minor
+version with leading zero, and release number with leading zero,
+(e.g., libpng_vn for version 1.0.7 is 10007).
+
+Note that this function does not take a png_ptr, so you can call it
+before you've created one.
+
+You can also check which version of png.h you used when compiling your
+application:
+
+   png_uint_32 application_vn = PNG_LIBPNG_VER;
+
+.SH IX. Changes to Libpng from version 1.0.x to 1.2.x
+
+Support for user memory management was enabled by default.  To
+accomplish this, the functions png_create_read_struct_2(),
+png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
+png_malloc_default(), and png_free_default() were added.
+
+Support for the iTXt chunk has been enabled by default as of
+version 1.2.41.
+
+Support for certain MNG features was enabled.
+
+Support for numbered error messages was added.  However, we never got
+around to actually numbering the error messages.  The function
+png_set_strip_error_numbers() was added (Note: the prototype for this
+function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
+builds of libpng-1.2.15.  It was restored in libpng-1.2.36).
+
+The png_malloc_warn() function was added at libpng-1.2.3.  This issues
+a png_warning and returns NULL instead of aborting when it fails to
+acquire the requested memory allocation.
+
+Support for setting user limits on image width and height was enabled
+by default.  The functions png_set_user_limits(), png_get_user_width_max(),
+and png_get_user_height_max() were added at libpng-1.2.6.
+
+The png_set_add_alpha() function was added at libpng-1.2.7.
+
+The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
+Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
+tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
+deprecated.
+
+A number of macro definitions in support of runtime selection of
+assembler code features (especially Intel MMX code support) were
+added at libpng-1.2.0:
+
+    PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
+    PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+    PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
+    PNG_ASM_FLAG_MMX_READ_INTERLACE
+    PNG_ASM_FLAG_MMX_READ_FILTER_SUB
+    PNG_ASM_FLAG_MMX_READ_FILTER_UP
+    PNG_ASM_FLAG_MMX_READ_FILTER_AVG
+    PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
+    PNG_ASM_FLAGS_INITIALIZED
+    PNG_MMX_READ_FLAGS
+    PNG_MMX_FLAGS
+    PNG_MMX_WRITE_FLAGS
+    PNG_MMX_FLAGS
+
+We added the following functions in support of runtime
+selection of assembler code features:
+
+    png_get_mmx_flagmask()
+    png_set_mmx_thresholds()
+    png_get_asm_flags()
+    png_get_mmx_bitdepth_threshold()
+    png_get_mmx_rowbytes_threshold()
+    png_set_asm_flags()
+
+We replaced all of these functions with simple stubs in libpng-1.2.20,
+when the Intel assembler code was removed due to a licensing issue.
+
+These macros are deprecated:
+
+    PNG_READ_TRANSFORMS_NOT_SUPPORTED
+    PNG_PROGRESSIVE_READ_NOT_SUPPORTED
+    PNG_NO_SEQUENTIAL_READ_SUPPORTED
+    PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
+    PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
+    PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+They have been replaced, respectively, by:
+
+    PNG_NO_READ_TRANSFORMS
+    PNG_NO_PROGRESSIVE_READ
+    PNG_NO_SEQUENTIAL_READ
+    PNG_NO_WRITE_TRANSFORMS
+    PNG_NO_READ_ANCILLARY_CHUNKS
+    PNG_NO_WRITE_ANCILLARY_CHUNKS
+
+PNG_MAX_UINT was replaced with PNG_UINT_31_MAX.  It has been
+deprecated since libpng-1.0.16 and libpng-1.2.6.
+
+The function
+    png_check_sig(sig, num)
+was replaced with
+    png_sig_cmp(sig, 0, num) == 0
+It has been deprecated since libpng-0.90.
+
+The function
+    png_set_gray_1_2_4_to_8()
+which also expands tRNS to alpha was replaced with
+    png_set_expand_gray_1_2_4_to_8()
+which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
+
+.SH X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+
+Private libpng prototypes and macro definitions were moved from
+png.h and pngconf.h into a new pngpriv.h header file.
+
+Functions png_set_benign_errors(), png_benign_error(), and
+png_chunk_benign_error() were added.
+
+Support for setting the maximum amount of memory that the application
+will allocate for reading chunks was added, as a security measure.
+The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
+were added to the library.
+
+We implemented support for I/O states by adding png_ptr member io_state
+and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+
+We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
+input transforms.
+
+Checking for and reporting of errors in the IHDR chunk is more thorough.
+
+Support for global arrays was removed, to improve thread safety.
+
+Some obsolete/deprecated macros and functions have been removed.
+
+Typecasted NULL definitions such as
+   #define png_voidp_NULL            (png_voidp)NULL
+were eliminated.  If you used these in your application, just use
+NULL instead.
+
+The png_struct and info_struct members "trans" and "trans_values" were
+changed to "trans_alpha" and "trans_color", respectively.
+
+The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
+were removed.
+
+The PNG_1_0_X and PNG_1_2_X macros were eliminated.
+
+The PNG_LEGACY_SUPPORTED macro was eliminated.
+
+Many WIN32_WCE #ifdefs were removed.
+
+The functions png_read_init(info_ptr), png_write_init(info_ptr),
+png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
+have been removed.  They have been deprecated since libpng-0.95.
+
+The png_permit_empty_plte() was removed. It has been deprecated
+since libpng-1.0.9.  Use png_permit_mng_features() instead.
+
+We removed the obsolete stub functions png_get_mmx_flagmask(),
+png_set_mmx_thresholds(), png_get_asm_flags(),
+png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
+png_set_asm_flags(), and png_mmx_supported()
+
+We removed the obsolete png_check_sig(), png_memcpy_check(), and
+png_memset_check() functions.  Instead use png_sig_cmp() == 0,
+memcpy(), and memset(), respectively.
+
+The function png_set_gray_1_2_4_to_8() was removed. It has been
+deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
+png_set_expand_gray_1_2_4_to_8() because the former function also
+expanded any tRNS chunk to an alpha channel.
+
+Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32
+were added and are used by default instead of the corresponding
+functions. Unfortunately,
+from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+
+We changed the prototype for png_malloc() from
+    png_malloc(png_structp png_ptr, png_uint_32 size)
+to
+    png_malloc(png_structp png_ptr, png_alloc_size_t size)
+
+This also applies to the prototype for the user replacement malloc_fn().
+
+The png_calloc() function was added and is used in place of
+of "png_malloc(); memset();" except in the case in png_read_png()
+where the array consists of pointers; in this case a "for" loop is used
+after the png_malloc() to set the pointers to NULL, to give robust.
+behavior in case the application runs out of memory part-way through
+the process.
+
+We changed the prototypes of png_get_compression_buffer_size() and
+png_set_compression_buffer_size() to work with size_t instead of
+png_uint_32.
+
+Support for numbered error messages was removed by default, since we
+never got around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was removed from the library by default.
+
+The png_zalloc() and png_zfree() functions are no longer exported.
+The png_zalloc() function no longer zeroes out the memory that it
+allocates.  Applications that called png_zalloc(png_ptr, number, size)
+can call png_calloc(png_ptr, number*size) instead, and can call
+png_free() instead of png_zfree().
+
+Support for dithering was disabled by default in libpng-1.4.0, because
+it has not been well tested and doesn't actually "dither".
+The code was not
+removed, however, and could be enabled by building libpng with
+PNG_READ_DITHER_SUPPORTED defined.  In libpng-1.4.2, this support
+was re-enabled, but the function was renamed png_set_quantize() to
+reflect more accurately what it actually does.  At the same time,
+the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
+PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED
+was renamed to PNG_READ_QUANTIZE_SUPPORTED.
+
+We removed the trailing '.' from the warning and error messages.
+
+.SH XI. Changes to Libpng from version 1.4.x to 1.5.x
+
+From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+The incorrect macro was removed from libpng-1.4.5.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10.  If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error.  This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+   png_set_check_for_invalid_index(png_ptr, allowed);
+
+      allowed  - one of
+                 0: disable benign error (accept the
+                    invalid data without warning).
+                 1: enable benign error (treat the
+                    invalid data as an error or a
+                    warning).
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are decoded as opaque black by the decoder and written
+as-is by the encoder.
+
+Retrieving the maximum palette index found was added at libpng-1.5.15.
+This statement must appear after png_read_png() or png_read_image() while
+reading, and after png_write_png() or png_write_image() while writing.
+
+   int max_palette = png_get_palette_max(png_ptr, info_ptr);
+
+This will return the maximum palette index found in the image, or "\-1" if
+the palette was not checked, or "0" if no palette was found.  Note that this
+does not account for any palette index used by ancillary chunks such as the
+bKGD chunk; you must check those separately to determine the maximum
+palette index actually used.
+
+There are no substantial API changes between the non-deprecated parts of
+the 1.4.5 API and the 1.5.0 API; however, the ability to directly access
+members of the main libpng control structures, png_struct and png_info,
+deprecated in earlier versions of libpng, has been completely removed from
+libpng 1.5, and new private "pngstruct.h", "pnginfo.h", and "pngdebug.h"
+header files were created.
+
+We no longer include zlib.h in png.h.  The include statement has been moved
+to pngstruct.h, where it is not accessible by applications. Applications that
+need access to information in zlib.h will need to add the '#include "zlib.h"'
+directive.  It does not matter whether this is placed prior to or after
+the '"#include png.h"' directive.
+
+The png_sprintf(), png_strcpy(), and png_strncpy() macros are no longer used
+and were removed.
+
+We moved the png_strlen(), png_memcpy(), png_memset(), and png_memcmp()
+macros into a private header file (pngpriv.h) that is not accessible to
+applications.
+
+In png_get_iCCP, the type of "profile" was changed from png_charpp
+to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep.
+
+There are changes of form in png.h, including new and changed macros to
+declare parts of the API.  Some API functions with arguments that are
+pointers to data not modified within the function have been corrected to
+declare these arguments with const.
+
+Much of the internal use of C macros to control the library build has also
+changed and some of this is visible in the exported header files, in
+particular the use of macros to control data and API elements visible
+during application compilation may require significant revision to
+application code.  (It is extremely rare for an application to do this.)
+
+Any program that compiled against libpng 1.4 and did not use deprecated
+features or access internal library structures should compile and work
+against libpng 1.5, except for the change in the prototype for
+png_get_iCCP() and png_set_iCCP() API functions mentioned above.
+
+libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of
+interlaced images.  The macros return the number of rows and columns in
+each pass and information that can be used to de-interlace and (if
+absolutely necessary) interlace an image.
+
+libpng 1.5.0 adds an API png_longjmp(png_ptr, value).  This API calls
+the application-provided png_longjmp_ptr on the internal, but application
+initialized, longjmp buffer.  It is provided as a convenience to avoid
+the need to use the png_jmpbuf macro, which had the unnecessary side
+effect of resetting the internal png_longjmp_ptr value.
+
+libpng 1.5.0 includes a complete fixed point API.  By default this is
+present along with the corresponding floating point API.  In general the
+fixed point API is faster and smaller than the floating point one because
+the PNG file format used fixed point, not floating point.  This applies
+even if the library uses floating point in internal calculations.  A new
+macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library
+uses floating point arithmetic (the default) or fixed point arithmetic
+internally for performance critical calculations such as gamma correction.
+In some cases, the gamma calculations may produce slightly different
+results.  This has changed the results in png_rgb_to_gray and in alpha
+composition (png_set_background for example). This applies even if the
+original image was already linear (gamma == 1.0) and, therefore, it is
+not necessary to linearize the image.  This is because libpng has *not*
+been changed to optimize that case correctly, yet.
+
+Fixed point support for the sCAL chunk comes with an important caveat;
+the sCAL specification uses a decimal encoding of floating point values
+and the accuracy of PNG fixed point values is insufficient for
+representation of these values. Consequently a "string" API
+(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
+arbitrary sCAL chunks in the absence of either the floating point API or
+internal floating point calculations.  Starting with libpng-1.5.0, both
+of these functions are present when PNG_sCAL_SUPPORTED is defined.  Prior
+to libpng-1.5.0, their presence also depended upon PNG_FIXED_POINT_SUPPORTED
+being defined and PNG_FLOATING_POINT_SUPPORTED not being defined.
+
+Applications no longer need to include the optional distribution header
+file pngusr.h or define the corresponding macros during application
+build in order to see the correct variant of the libpng API.  From 1.5.0
+application code can check for the corresponding _SUPPORTED macro:
+
+#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
+   /* code that uses the inch conversion APIs. */
+#endif
+
+This macro will only be defined if the inch conversion functions have been
+compiled into libpng.  The full set of macros, and whether or not support
+has been compiled in, are available in the header file pnglibconf.h.
+This header file is specific to the libpng build.  Notice that prior to
+1.5.0 the _SUPPORTED macros would always have the default definition unless
+reset by pngusr.h or by explicit settings on the compiler command line.
+These settings may produce compiler warnings or errors in 1.5.0 because
+of macro redefinition.
+
+Applications can now choose whether to use these macros or to call the
+corresponding function by defining PNG_USE_READ_MACROS or
+PNG_NO_USE_READ_MACROS before including png.h.  Notice that this is
+only supported from 1.5.0; defining PNG_NO_USE_READ_MACROS prior to 1.5.0
+will lead to a link failure.
+
+Prior to libpng-1.5.4, the zlib compressor used the same set of parameters
+when compressing the IDAT data and textual data such as zTXt and iCCP.
+In libpng-1.5.4 we reinitialized the zlib stream for each type of data.
+We added five png_set_text_*() functions for setting the parameters to
+use with textual data.
+
+Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+option was off by default, and slightly inaccurate scaling occurred.
+This option can no longer be turned off, and the choice of accurate
+or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
+API for accurate scaling or the old png_set_strip_16_to_8() API for simple
+chopping.  In libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+macro became PNG_READ_SCALE_16_TO_8_SUPPORTED, and the PNG_READ_16_TO_8
+macro became PNG_READ_STRIP_16_TO_8_SUPPORTED, to enable the two
+png_set_*_16_to_8() functions separately.
+
+Prior to libpng-1.5.4, the png_set_user_limits() function could only be
+used to reduce the width and height limits from the value of
+PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
+that it could be used to override them.  Now this function will reduce or
+increase the limits.
+
+Starting in libpng-1.5.22, default user limits were established. These
+can be overridden by application calls to png_set_user_limits(),
+png_set_user_chunk_cache_max(), and/or png_set_user_malloc_max().
+The limits are now
+                             max possible  default
+   png_user_width_max        0x7fffffff    1,000,000
+   png_user_height_max       0x7fffffff    1,000,000
+   png_user_chunk_cache_max  0 (unlimited) 1000
+   png_user_chunk_malloc_max 0 (unlimited) 8,000,000
+
+The png_set_option() function (and the "options" member of the png struct) was
+added to libpng-1.5.15, with option PNG_ARM_NEON.
+
+The library now supports a complete fixed point implementation and can
+thus be used on systems that have no floating point support or very
+limited or slow support.  Previously gamma correction, an essential part
+of complete PNG support, required reasonably fast floating point.
+
+As part of this the choice of internal implementation has been made
+independent of the choice of fixed versus floating point APIs and all the
+missing fixed point APIs have been implemented.
+
+The exact mechanism used to control attributes of API functions has
+changed, as described in the INSTALL file.
+
+A new test program, pngvalid, is provided in addition to pngtest.
+pngvalid validates the arithmetic accuracy of the gamma correction
+calculations and includes a number of validations of the file format.
+A subset of the full range of tests is run when "make check" is done
+(in the 'configure' build.)  pngvalid also allows total allocated memory
+usage to be evaluated and performs additional memory overwrite validation.
+
+Many changes to individual feature macros have been made. The following
+are the changes most likely to be noticed by library builders who
+configure libpng:
+
+1) All feature macros now have consistent naming:
+
+#define PNG_NO_feature turns the feature off
+#define PNG_feature_SUPPORTED turns the feature on
+
+pnglibconf.h contains one line for each feature macro which is either:
+
+#define PNG_feature_SUPPORTED
+
+if the feature is supported or:
+
+/*#undef PNG_feature_SUPPORTED*/
+
+if it is not.  Library code consistently checks for the 'SUPPORTED' macro.
+It does not, and libpng applications should not, check for the 'NO' macro
+which will not normally be defined even if the feature is not supported.
+The 'NO' macros are only used internally for setting or not setting the
+corresponding 'SUPPORTED' macros.
+
+Compatibility with the old names is provided as follows:
+
+PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED
+
+And the following definitions disable the corresponding feature:
+
+PNG_SETJMP_NOT_SUPPORTED disables SETJMP
+PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS
+PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV
+PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS
+PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS
+PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS
+
+Library builders should remove use of the above, inconsistent, names.
+
+2) Warning and error message formatting was previously conditional on
+the STDIO feature. The library has been changed to use the
+CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled
+the library no longer uses the printf(3) functions, even though the
+default read/write implementations use (FILE) style stdio.h functions.
+
+3) Three feature macros now control the fixed/floating point decisions:
+
+PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs
+
+PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in
+practice these are normally required internally anyway (because the PNG
+file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT
+merely stops the function from being exported.
+
+PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating
+point implementation or the fixed point one.  Typically the fixed point
+implementation is larger and slower than the floating point implementation
+on a system that supports floating point; however, it may be faster on a
+system which lacks floating point hardware and therefore uses a software
+emulation.
+
+4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the
+functions to read and write ints to be disabled independently of
+PNG_USE_READ_MACROS, which allows libpng to be built with the functions
+even though the default is to use the macros - this allows applications
+to choose at app buildtime whether or not to use macros (previously
+impossible because the functions weren't in the default build.)
+
+.SH XII. Changes to Libpng from version 1.5.x to 1.6.x
+
+A "simplified API" has been added (see documentation in png.h and a simple
+example in contrib/examples/pngtopng.c).  The new publicly visible API
+includes the following:
+
+   macros:
+     PNG_FORMAT_*
+     PNG_IMAGE_*
+   structures:
+     png_control
+     png_image
+   read functions
+     png_image_begin_read_from_file()
+     png_image_begin_read_from_stdio()
+     png_image_begin_read_from_memory()
+     png_image_finish_read()
+     png_image_free()
+   write functions
+     png_image_write_to_file()
+     png_image_write_to_memory()
+     png_image_write_to_stdio()
+
+Starting with libpng-1.6.0, you can configure libpng to prefix all exported
+symbols, using the PNG_PREFIX macro.
+
+We no longer include string.h in png.h.  The include statement has been moved
+to pngpriv.h, where it is not accessible by applications.  Applications that
+need access to information in string.h must add an '#include <string.h>'
+directive.  It does not matter whether this is placed prior to or after
+the '#include "png.h"' directive.
+
+The following API are now DEPRECATED:
+   png_info_init_3()
+   png_convert_to_rfc1123() which has been replaced
+     with png_convert_to_rfc1123_buffer()
+   png_malloc_default()
+   png_free_default()
+   png_reset_zstream()
+
+The following have been removed:
+   png_get_io_chunk_name(), which has been replaced
+     with png_get_io_chunk_type().  The new
+     function returns a 32-bit integer instead of
+     a string.
+   The png_sizeof(), png_strlen(), png_memcpy(), png_memcmp(), and
+     png_memset() macros are no longer used in the libpng sources and
+     have been removed.  These had already been made invisible to applications
+     (i.e., defined in the private pngpriv.h header file) since libpng-1.5.0.
+
+The signatures of many exported functions were changed, such that
+   png_structp became png_structrp or png_const_structrp
+   png_infop became png_inforp or png_const_inforp
+where "rp" indicates a "restricted pointer".
+
+Dropped support for 16-bit platforms. The support for FAR/far types has
+been eliminated and the definition of png_alloc_size_t is now controlled
+by a flag so that 'small size_t' systems can select it if necessary.
+
+Error detection in some chunks has improved; in particular the iCCP chunk
+reader now does pretty complete validation of the basic format.  Some bad
+profiles that were previously accepted are now accepted with a warning or
+rejected, depending upon the png_set_benign_errors() setting, in particular
+the very old broken Microsoft/HP 3144-byte sRGB profile.  Starting with
+libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
+means of
+
+    #if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && \
+        defined(PNG_SET_OPTION_SUPPORTED)
+       png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE,
+           PNG_OPTION_ON);
+    #endif
+
+It's not a good idea to do this if you are using the "simplified API",
+which needs to be able to recognize sRGB profiles conveyed via the iCCP
+chunk.
+
+The PNG spec requirement that only grayscale profiles may appear in images
+with color type 0 or 4 and that even if the image only contains gray pixels,
+only RGB profiles may appear in images with color type 2, 3, or 6, is now
+enforced.  The sRGB chunk is allowed to appear in images with any color type
+and is interpreted by libpng to convey a one-tracer-curve gray profile or a
+three-tracer-curve RGB profile as appropriate.
+
+Libpng 1.5.x erroneously used /MD for Debug DLL builds; if you used the debug
+builds in your app and you changed your app to use /MD you will need to
+change it back to /MDd for libpng 1.6.x.
+
+Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
+an empty language field or an empty translated keyword.  Both of these
+are allowed by the PNG specification, so these warnings are no longer issued.
+
+The library now issues an error if the application attempts to set a
+transform after it calls png_read_update_info() or if it attempts to call
+both png_read_update_info() and png_start_read_image() or to call either
+of them more than once.
+
+The default condition for benign_errors is now to treat benign errors as
+warnings while reading and as errors while writing.
+
+The library now issues a warning if both background processing and RGB to
+gray are used when gamma correction happens. As with previous versions of
+the library the results are numerically very incorrect in this case.
+
+There are some minor arithmetic changes in some transforms such as
+png_set_background(), that might be detected by certain regression tests.
+
+Unknown chunk handling has been improved internally, without any API change.
+This adds more correct option control of the unknown handling, corrects
+a pre-existing bug where the per-chunk 'keep' setting is ignored, and makes
+it possible to skip IDAT chunks in the sequential reader.
+
+The machine-generated configure files are no longer included in branches
+libpng16 and later of the GIT repository.  They continue to be included
+in the tarball releases, however.
+
+Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT
+stream to set the size of the sliding window for reading instead of using the
+default 32-kbyte sliding window size.  It was discovered that there are
+hundreds of PNG files in the wild that have incorrect CMF bytes that caused
+zlib to issue the "invalid distance too far back" error and reject the file.
+Libpng-1.6.3 and later calculate their own safe CMF from the image dimensions,
+provide a way to revert to the libpng-1.5.x behavior (ignoring the CMF bytes
+and using a 32-kbyte sliding window), by using
+
+    png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW,
+        PNG_OPTION_ON);
+
+and provide a tool (contrib/tools/pngfix) for rewriting a PNG file while
+optimizing the CMF bytes in its IDAT chunk correctly.
+
+Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
+length, which resulted in PNG files that cannot be read beyond the bad iTXt
+chunk.  This error was fixed in libpng-1.6.3, and a tool (called
+contrib/tools/png-fix-itxt) has been added to the libpng distribution.
+
+Starting with libpng-1.6.17, the PNG_SAFE_LIMITS macro was eliminated
+and safe limits are used by default (users who need larger limits
+can still override them at compile time or run time, as described above).
+
+The new limits are
+                                default   spec limit
+   png_user_width_max         1,000,000  2,147,483,647
+   png_user_height_max        1,000,000  2,147,483,647
+   png_user_chunk_cache_max         128  unlimited
+   png_user_chunk_malloc_max  8,000,000  unlimited
+
+Starting with libpng-1.6.18, a PNG_RELEASE_BUILD macro was added, which allows
+library builders to control compilation for an installed system (a release build).
+It can be set for testing debug or beta builds to ensure that they will compile
+when the build type is switched to RC or STABLE. In essence this overrides the
+PNG_LIBPNG_BUILD_BASE_TYPE definition which is not directly user controllable.
+
+Starting with libpng-1.6.19, attempting to set an over-length PLTE chunk
+is an error. Previously this requirement of the PNG specification was not
+enforced, and the palette was always limited to 256 entries. An over-length
+PLTE chunk found in an input PNG is silently truncated.
+
+Starting with libpng-1.6.31, the eXIf chunk is supported. Libpng does not
+attempt to decode the Exif profile; it simply returns a byte array
+containing the profile to the calling application which must do its own
+decoding.
+
+.SH XIII. Detecting libpng
+
+The png_get_io_ptr() function has been present since libpng-0.88, has never
+changed, and is unaffected by conditional compilation macros.  It is the
+best choice for use in configure scripts for detecting the presence of any
+libpng version since 0.88.  In an autoconf "configure.in" you could use
+
+    AC_CHECK_LIB(png, png_get_io_ptr, ...)
+
+.SH XV. Source code repository
+
+Since about February 2009, version 1.2.34, libpng has been under "git" source
+control.  The git repository was built from old libpng-x.y.z.tar.gz files
+going back to version 0.70.  You can access the git repository (read only)
+at
+
+    https://github.com/pnggroup/libpng or
+    https://git.code.sf.net/p/libpng/code.git
+
+or you can browse it with a web browser at
+
+    https://github.com/pnggroup/libpng or
+    https://sourceforge.net/p/libpng/code/ci/libpng16/tree/
+
+Patches can be sent to png-mng-implement at lists.sourceforge.net or
+uploaded to the libpng bug tracker at
+
+    https://libpng.sourceforge.io/
+
+or as a "pull request" to
+
+    https://github.com/pnggroup/libpng/pulls
+
+We also accept patches built from the tar or zip distributions, and
+simple verbal descriptions of bug fixes, reported either to the
+SourceForge bug tracker, to the png-mng-implement at lists.sf.net
+mailing list, as github issues.
+
+.SH XV. Coding style
+
+Our coding style is similar to the "Allman" style
+(See https://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
+braces on separate lines:
+
+    if (condition)
+    {
+       action;
+    }
+
+    else if (another condition)
+    {
+       another action;
+    }
+
+The braces can be omitted from simple one-line actions:
+
+    if (condition)
+       return 0;
+
+We use 3-space indentation, except for continued statements which
+are usually indented the same as the first line of the statement
+plus four more spaces.
+
+For macro definitions we use 2-space indentation, always leaving the "#"
+in the first column.
+
+    #ifndef PNG_NO_FEATURE
+    #  ifndef PNG_FEATURE_SUPPORTED
+    #    define PNG_FEATURE_SUPPORTED
+    #  endif
+    #endif
+
+Comments appear with the leading "/*" at the same indentation as
+the statement that follows the comment:
+
+    /* Single-line comment */
+    statement;
+
+    /* This is a multiple-line
+     * comment.
+     */
+    statement;
+
+Very short comments can be placed after the end of the statement
+to which they pertain:
+
+    statement;    /* comment */
+
+We don't use C++ style ("//") comments. We have, however,
+used them in the past in some now-abandoned MMX assembler
+code.
+
+Functions and their curly braces are not indented, and
+exported functions are marked with PNGAPI:
+
+ /* This is a public function that is visible to
+  * application programmers. It does thus-and-so.
+  */
+ void PNGAPI
+ png_exported_function(png_ptr, png_info, foo)
+ {
+    body;
+ }
+
+The return type and decorations are placed on a separate line
+ahead of the function name, as illustrated above.
+
+The prototypes for all exported functions appear in png.h,
+above the comment that says
+
+    /* Maintainer: Put new public prototypes here ... */
+
+We mark all non-exported functions with "/* PRIVATE */"":
+
+ void /* PRIVATE */
+ png_non_exported_function(png_ptr, png_info, foo)
+ {
+    body;
+ }
+
+The prototypes for non-exported functions (except for those in
+pngtest) appear in pngpriv.h above the comment that says
+
+  /* Maintainer: Put new private prototypes here ^ */
+
+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG".  We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
+We put a space after the "sizeof" operator and we omit the
+optional parentheses around its argument when the argument
+is an expression, not a type name, and we always enclose the
+sizeof operator, with its argument, in parentheses:
+
+  (sizeof (png_uint_32))
+  (sizeof array)
+
+Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
+though it were a function.
+
+Control keywords if, for, while, and switch are always followed by a space
+to distinguish them from function calls, which have no trailing space.
+
+We put a space after each comma and after each semicolon
+in "for" statements, and we put spaces before and after each
+C binary operator and after "for" or "while", and before
+"?".  We don't put a space between a typecast and the expression
+being cast, nor do we put one between a function name and the
+left parenthesis that follows it:
+
+    for (i = 2; i > 0; \-\-i)
+       y[i] = a(x) + (int)b;
+
+We prefer #ifdef and #ifndef to #if defined() and #if !defined()
+when there is only one macro being tested.  We always use parentheses
+with "defined".
+
+We express integer constants that are used as bit masks in hex format,
+with an even number of lower-case hex digits, and to make them unsigned
+(e.g., 0x00U, 0xffU, 0x0100U) and long if they are greater than 0x7fff
+(e.g., 0xffffUL).
+
+We prefer to use underscores rather than camelCase in names, except
+for a few type names that we inherit from zlib.h.
+
+We prefer "if (something != 0)" and "if (something == 0)" over
+"if (something)" and if "(!something)", respectively, and for pointers
+we prefer "if (some_pointer != NULL)" or "if (some_pointer == NULL)".
+
+We do not use the TAB character for indentation in the C sources.
+
+Lines do not exceed 80 characters.
+
+Other rules can be inferred by inspecting the libpng source.
+
+.SH NOTE
+
+Note about libpng version numbers:
+
+Due to various miscommunications, unforeseen code incompatibilities
+and occasional factors outside the authors' control, version numbering
+on the library has not always been consistent and straightforward.
+The following table summarizes matters since version 0.89c, which was
+the first widely used release:
+
+ source               png.h    png.h  shared-lib
+ version              string   int    version
+ -------              ------   -----  ----------
+ 0.89c "1.0 beta 3"     0.89      89  1.0.89
+ 0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
+ 0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
+ 0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
+ 0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
+ 0.97c                  0.97      97  2.0.97
+ 0.98                   0.98      98  2.0.98
+ 0.99                   0.99      98  2.0.99
+ 0.99a-m                0.99      99  2.0.99
+ 1.00                   1.00     100  2.1.0 [100 should be 10000]
+ 1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
+ 1.0.1       png.h string is   10001  2.1.0
+ 1.0.1a-e    identical to the  10002  from here on, the shared library
+ 1.0.2       source version)   10002  is 2.V where V is the source code
+ 1.0.2a-b                      10003  version, except as noted.
+ 1.0.3                         10003
+ 1.0.3a-d                      10004
+ 1.0.4                         10004
+ 1.0.4a-f                      10005
+ 1.0.5 (+ 2 patches)           10005
+ 1.0.5a-d                      10006
+ 1.0.5e-r                      10100 (not source compatible)
+ 1.0.5s-v                      10006 (not binary compatible)
+ 1.0.6 (+ 3 patches)           10006 (still binary incompatible)
+ 1.0.6d-f                      10007 (still binary incompatible)
+ 1.0.6g                        10007
+ 1.0.6h                        10007  10.6h (testing xy.z so-numbering)
+ 1.0.6i                        10007  10.6i
+ 1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
+ 1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
+ 1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
+ 1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
+ 1.0.7                    1    10007  (still compatible)
+ ...
+ 1.0.69                  10    10069  10.so.0.69[.0]
+ ...
+ 1.2.59                  13    10259  12.so.0.59[.0]
+ ...
+ 1.4.20                  14    10420  14.so.0.20[.0]
+ ...
+ 1.5.30                  15    10530  15.so.15.30[.0]
+ ...
+ 1.6.35                  16    10635  16.so.16.35[.0]
+
+Henceforth the source version will match the shared-library minor and
+patch numbers; the shared-library major version number will be used for
+changes in backward compatibility, as it is intended.
+The PNG_PNGLIB_VER macro, which is not used within libpng but is
+available for applications, is an unsigned integer of the form XYYZZ
+corresponding to the source version X.Y.Z (leading zeros in Y and Z).
+Beta versions were given the previous public release number plus a
+letter, until version 1.0.6j; from then on they were given the upcoming
+public release number plus "betaNN" or "rcNN".
+
+.SH "SEE ALSO"
+.BR "png"(5)
+.IP
+The PNG (Portable Network Graphics) format specification.
+.LP
+.B libpng
+.IP
+http://www.libpng.org/pub/png/libpng.html (canonical home page)
+.br
+https://github.com/pnggroup/libpng (canonical Git repository)
+.br
+https://libpng.sourceforge.io (downloadable archives)
+.LP
+.B zlib
+.IP
+https://zlib.net (canonical home page)
+.br
+https://github.com/madler/zlib (canonical Git repository)
+.br
+A copy of zlib may also be found at the same location as libpng.
+.LP
+In the case of any inconsistency between the PNG specification
+and this library, the specification takes precedence.
+
+.SH AUTHORS
+This man page:
+Initially created by Glenn Randers-Pehrson.
+Maintained by Cosmin Truta.
+
+The contributing authors would like to thank all those who helped
+with testing, bug fixes, and patience.  This wouldn't have been
+possible without all of you.
+
+Thanks to Frank J. T. Wojcik for helping with the documentation.
+
+Libpng:
+Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
+Maintained by Cosmin Truta.
+
+Supported by the PNG development group.
+.br
+png-mng-implement at lists.sourceforge.net. (Subscription is required;
+visit https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe.)
+
+.\" end of man page
Index: /trunk/src/libs/libpng-1.6.45/libpng.pc.in
===================================================================
--- /trunk/src/libs/libpng-1.6.45/libpng.pc.in	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/libpng.pc.in	(revision 107811)
@@ -0,0 +1,12 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+
+Name: libpng
+Description: Loads and saves PNG files
+Version: @PNGLIB_VERSION@
+Requires.private: zlib
+Libs: -L${libdir} -lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+Libs.private: @LIBS@
+Cflags: -I${includedir}
Index: /trunk/src/libs/libpng-1.6.45/libpngpf.3
===================================================================
--- /trunk/src/libs/libpng-1.6.45/libpngpf.3	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/libpngpf.3	(revision 107811)
@@ -0,0 +1,24 @@
+.TH LIBPNGPF 3 "February 23, 2024"
+.SH NAME
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.43
+(private functions)
+
+.SH SYNOPSIS
+\fB#include \fI"pngpriv.h"
+
+\fBAs of libpng version \fP\fI1.5.1\fP\fB, this section is no longer
+\fP\fImaintained\fP\fB, now that the private function prototypes are hidden in
+\fP\fIpngpriv.h\fP\fB and not accessible to applications. Look in
+\fP\fIpngpriv.h\fP\fB for the prototypes and a short description of each
+function.
+
+.SH DESCRIPTION
+The functions previously listed here are used privately by libpng and are not
+available for use by applications.  They are not "exported" to applications
+using shared libraries.
+
+.SH "SEE ALSO"
+.BR "png"(5), " libpng"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
+
+.SH AUTHORS
+Cosmin Truta, Glenn Randers-Pehrson
Index: /trunk/src/libs/libpng-1.6.45/ltmain.sh
===================================================================
--- /trunk/src/libs/libpng-1.6.45/ltmain.sh	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/ltmain.sh	(revision 107811)
@@ -0,0 +1,11436 @@
+#! /usr/bin/env sh
+## DO NOT EDIT - This file generated from ./build-aux/ltmain.in
+##               by inline-source v2019-02-19.15
+
+# libtool (GNU libtool) 2.4.7
+# Provide generalized library-building support services.
+# Written by Gordon Matzigkeit <gord@gnu.ai.mit.edu>, 1996
+
+# Copyright (C) 1996-2019, 2021-2022 Free Software Foundation, Inc.
+# This is free software; see the source for copying conditions.  There is NO
+# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+# GNU Libtool is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# As a special exception to the GNU General Public License,
+# if you distribute this file as part of a program or library that
+# is built using GNU Libtool, you may include this file under the
+# same distribution terms that you use for the rest of that program.
+#
+# GNU Libtool is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+PROGRAM=libtool
+PACKAGE=libtool
+VERSION=2.4.7
+package_revision=2.4.7
+
+
+## ------ ##
+## Usage. ##
+## ------ ##
+
+# Run './libtool --help' for help with using this script from the
+# command line.
+
+
+## ------------------------------- ##
+## User overridable command paths. ##
+## ------------------------------- ##
+
+# After configure completes, it has a better idea of some of the
+# shell tools we need than the defaults used by the functions shared
+# with bootstrap, so set those here where they can still be over-
+# ridden by the user, but otherwise take precedence.
+
+: ${AUTOCONF="autoconf"}
+: ${AUTOMAKE="automake"}
+
+
+## -------------------------- ##
+## Source external libraries. ##
+## -------------------------- ##
+
+# Much of our low-level functionality needs to be sourced from external
+# libraries, which are installed to $pkgauxdir.
+
+# Set a version string for this script.
+scriptversion=2019-02-19.15; # UTC
+
+# General shell script boiler plate, and helper functions.
+# Written by Gary V. Vaughan, 2004
+
+# This is free software.  There is NO warranty; not even for
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# Copyright (C) 2004-2019, 2021 Bootstrap Authors
+#
+# This file is dual licensed under the terms of the MIT license
+# <https://opensource.org/license/MIT>, and GPL version 2 or later
+# <http://www.gnu.org/licenses/gpl-2.0.html>.  You must apply one of
+# these licenses when using or redistributing this software or any of
+# the files within it.  See the URLs above, or the file `LICENSE`
+# included in the Bootstrap distribution for the full license texts.
+
+# Please report bugs or propose patches to:
+# <https://github.com/gnulib-modules/bootstrap/issues>
+
+
+## ------ ##
+## Usage. ##
+## ------ ##
+
+# Evaluate this file near the top of your script to gain access to
+# the functions and variables defined here:
+#
+#   . `echo "$0" | ${SED-sed} 's|[^/]*$||'`/build-aux/funclib.sh
+#
+# If you need to override any of the default environment variable
+# settings, do that before evaluating this file.
+
+
+## -------------------- ##
+## Shell normalisation. ##
+## -------------------- ##
+
+# Some shells need a little help to be as Bourne compatible as possible.
+# Before doing anything else, make sure all that help has been provided!
+
+DUALCASE=1; export DUALCASE # for MKS sh
+if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else
+  case `(set -o) 2>/dev/null` in *posix*) set -o posix ;; esac
+fi
+
+# NLS nuisances: We save the old values in case they are required later.
+_G_user_locale=
+_G_safe_locale=
+for _G_var in LANG LANGUAGE LC_ALL LC_CTYPE LC_COLLATE LC_MESSAGES
+do
+  eval "if test set = \"\${$_G_var+set}\"; then
+          save_$_G_var=\$$_G_var
+          $_G_var=C
+	  export $_G_var
+	  _G_user_locale=\"$_G_var=\\\$save_\$_G_var; \$_G_user_locale\"
+	  _G_safe_locale=\"$_G_var=C; \$_G_safe_locale\"
+	fi"
+done
+# These NLS vars are set unconditionally (bootstrap issue #24).  Unset those
+# in case the environment reset is needed later and the $save_* variant is not
+# defined (see the code above).
+LC_ALL=C
+LANGUAGE=C
+export LANGUAGE LC_ALL
+
+# Make sure IFS has a sensible default
+sp=' '
+nl='
+'
+IFS="$sp	$nl"
+
+# There are apparently some retarded systems that use ';' as a PATH separator!
+if test "${PATH_SEPARATOR+set}" != set; then
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
+    (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
+      PATH_SEPARATOR=';'
+  }
+fi
+
+
+# func_unset VAR
+# --------------
+# Portably unset VAR.
+# In some shells, an 'unset VAR' statement leaves a non-zero return
+# status if VAR is already unset, which might be problematic if the
+# statement is used at the end of a function (thus poisoning its return
+# value) or when 'set -e' is active (causing even a spurious abort of
+# the script in this case).
+func_unset ()
+{
+    { eval $1=; (eval unset $1) >/dev/null 2>&1 && eval unset $1 || : ; }
+}
+
+
+# Make sure CDPATH doesn't cause `cd` commands to output the target dir.
+func_unset CDPATH
+
+# Make sure ${,E,F}GREP behave sanely.
+func_unset GREP_OPTIONS
+
+
+## ------------------------- ##
+## Locate command utilities. ##
+## ------------------------- ##
+
+
+# func_executable_p FILE
+# ----------------------
+# Check that FILE is an executable regular file.
+func_executable_p ()
+{
+    test -f "$1" && test -x "$1"
+}
+
+
+# func_path_progs PROGS_LIST CHECK_FUNC [PATH]
+# --------------------------------------------
+# Search for either a program that responds to --version with output
+# containing "GNU", or else returned by CHECK_FUNC otherwise, by
+# trying all the directories in PATH with each of the elements of
+# PROGS_LIST.
+#
+# CHECK_FUNC should accept the path to a candidate program, and
+# set $func_check_prog_result if it truncates its output less than
+# $_G_path_prog_max characters.
+func_path_progs ()
+{
+    _G_progs_list=$1
+    _G_check_func=$2
+    _G_PATH=${3-"$PATH"}
+
+    _G_path_prog_max=0
+    _G_path_prog_found=false
+    _G_save_IFS=$IFS; IFS=${PATH_SEPARATOR-:}
+    for _G_dir in $_G_PATH; do
+      IFS=$_G_save_IFS
+      test -z "$_G_dir" && _G_dir=.
+      for _G_prog_name in $_G_progs_list; do
+        for _exeext in '' .EXE; do
+          _G_path_prog=$_G_dir/$_G_prog_name$_exeext
+          func_executable_p "$_G_path_prog" || continue
+          case `"$_G_path_prog" --version 2>&1` in
+            *GNU*) func_path_progs_result=$_G_path_prog _G_path_prog_found=: ;;
+            *)     $_G_check_func $_G_path_prog
+		   func_path_progs_result=$func_check_prog_result
+		   ;;
+          esac
+          $_G_path_prog_found && break 3
+        done
+      done
+    done
+    IFS=$_G_save_IFS
+    test -z "$func_path_progs_result" && {
+      echo "no acceptable sed could be found in \$PATH" >&2
+      exit 1
+    }
+}
+
+
+# We want to be able to use the functions in this file before configure
+# has figured out where the best binaries are kept, which means we have
+# to search for them ourselves - except when the results are already set
+# where we skip the searches.
+
+# Unless the user overrides by setting SED, search the path for either GNU
+# sed, or the sed that truncates its output the least.
+test -z "$SED" && {
+  _G_sed_script=s/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb/
+  for _G_i in 1 2 3 4 5 6 7; do
+    _G_sed_script=$_G_sed_script$nl$_G_sed_script
+  done
+  echo "$_G_sed_script" 2>/dev/null | sed 99q >conftest.sed
+  _G_sed_script=
+
+  func_check_prog_sed ()
+  {
+    _G_path_prog=$1
+
+    _G_count=0
+    printf 0123456789 >conftest.in
+    while :
+    do
+      cat conftest.in conftest.in >conftest.tmp
+      mv conftest.tmp conftest.in
+      cp conftest.in conftest.nl
+      echo '' >> conftest.nl
+      "$_G_path_prog" -f conftest.sed <conftest.nl >conftest.out 2>/dev/null || break
+      diff conftest.out conftest.nl >/dev/null 2>&1 || break
+      _G_count=`expr $_G_count + 1`
+      if test "$_G_count" -gt "$_G_path_prog_max"; then
+        # Best one so far, save it but keep looking for a better one
+        func_check_prog_result=$_G_path_prog
+        _G_path_prog_max=$_G_count
+      fi
+      # 10*(2^10) chars as input seems more than enough
+      test 10 -lt "$_G_count" && break
+    done
+    rm -f conftest.in conftest.tmp conftest.nl conftest.out
+  }
+
+  func_path_progs "sed gsed" func_check_prog_sed "$PATH:/usr/xpg4/bin"
+  rm -f conftest.sed
+  SED=$func_path_progs_result
+}
+
+
+# Unless the user overrides by setting GREP, search the path for either GNU
+# grep, or the grep that truncates its output the least.
+test -z "$GREP" && {
+  func_check_prog_grep ()
+  {
+    _G_path_prog=$1
+
+    _G_count=0
+    _G_path_prog_max=0
+    printf 0123456789 >conftest.in
+    while :
+    do
+      cat conftest.in conftest.in >conftest.tmp
+      mv conftest.tmp conftest.in
+      cp conftest.in conftest.nl
+      echo 'GREP' >> conftest.nl
+      "$_G_path_prog" -e 'GREP$' -e '-(cannot match)-' <conftest.nl >conftest.out 2>/dev/null || break
+      diff conftest.out conftest.nl >/dev/null 2>&1 || break
+      _G_count=`expr $_G_count + 1`
+      if test "$_G_count" -gt "$_G_path_prog_max"; then
+        # Best one so far, save it but keep looking for a better one
+        func_check_prog_result=$_G_path_prog
+        _G_path_prog_max=$_G_count
+      fi
+      # 10*(2^10) chars as input seems more than enough
+      test 10 -lt "$_G_count" && break
+    done
+    rm -f conftest.in conftest.tmp conftest.nl conftest.out
+  }
+
+  func_path_progs "grep ggrep" func_check_prog_grep "$PATH:/usr/xpg4/bin"
+  GREP=$func_path_progs_result
+}
+
+
+## ------------------------------- ##
+## User overridable command paths. ##
+## ------------------------------- ##
+
+# All uppercase variable names are used for environment variables.  These
+# variables can be overridden by the user before calling a script that
+# uses them if a suitable command of that name is not already available
+# in the command search PATH.
+
+: ${CP="cp -f"}
+: ${ECHO="printf %s\n"}
+: ${EGREP="$GREP -E"}
+: ${FGREP="$GREP -F"}
+: ${LN_S="ln -s"}
+: ${MAKE="make"}
+: ${MKDIR="mkdir"}
+: ${MV="mv -f"}
+: ${RM="rm -f"}
+: ${SHELL="${CONFIG_SHELL-/bin/sh}"}
+
+
+## -------------------- ##
+## Useful sed snippets. ##
+## -------------------- ##
+
+sed_dirname='s|/[^/]*$||'
+sed_basename='s|^.*/||'
+
+# Sed substitution that helps us do robust quoting.  It backslashifies
+# metacharacters that are still active within double-quoted strings.
+sed_quote_subst='s|\([`"$\\]\)|\\\1|g'
+
+# Same as above, but do not quote variable references.
+sed_double_quote_subst='s/\(["`\\]\)/\\\1/g'
+
+# Sed substitution that turns a string into a regex matching for the
+# string literally.
+sed_make_literal_regex='s|[].[^$\\*\/]|\\&|g'
+
+# Sed substitution that converts a w32 file name or path
+# that contains forward slashes, into one that contains
+# (escaped) backslashes.  A very naive implementation.
+sed_naive_backslashify='s|\\\\*|\\|g;s|/|\\|g;s|\\|\\\\|g'
+
+# Re-'\' parameter expansions in output of sed_double_quote_subst that
+# were '\'-ed in input to the same.  If an odd number of '\' preceded a
+# '$' in input to sed_double_quote_subst, that '$' was protected from
+# expansion.  Since each input '\' is now two '\'s, look for any number
+# of runs of four '\'s followed by two '\'s and then a '$'.  '\' that '$'.
+_G_bs='\\'
+_G_bs2='\\\\'
+_G_bs4='\\\\\\\\'
+_G_dollar='\$'
+sed_double_backslash="\
+  s/$_G_bs4/&\\
+/g
+  s/^$_G_bs2$_G_dollar/$_G_bs&/
+  s/\\([^$_G_bs]\\)$_G_bs2$_G_dollar/\\1$_G_bs2$_G_bs$_G_dollar/g
+  s/\n//g"
+
+# require_check_ifs_backslash
+# ---------------------------
+# Check if we can use backslash as IFS='\' separator, and set
+# $check_ifs_backshlash_broken to ':' or 'false'.
+require_check_ifs_backslash=func_require_check_ifs_backslash
+func_require_check_ifs_backslash ()
+{
+  _G_save_IFS=$IFS
+  IFS='\'
+  _G_check_ifs_backshlash='a\\b'
+  for _G_i in $_G_check_ifs_backshlash
+  do
+  case $_G_i in
+  a)
+    check_ifs_backshlash_broken=false
+    ;;
+  '')
+    break
+    ;;
+  *)
+    check_ifs_backshlash_broken=:
+    break
+    ;;
+  esac
+  done
+  IFS=$_G_save_IFS
+  require_check_ifs_backslash=:
+}
+
+
+## ----------------- ##
+## Global variables. ##
+## ----------------- ##
+
+# Except for the global variables explicitly listed below, the following
+# functions in the '^func_' namespace, and the '^require_' namespace
+# variables initialised in the 'Resource management' section, sourcing
+# this file will not pollute your global namespace with anything
+# else. There's no portable way to scope variables in Bourne shell
+# though, so actually running these functions will sometimes place
+# results into a variable named after the function, and often use
+# temporary variables in the '^_G_' namespace. If you are careful to
+# avoid using those namespaces casually in your sourcing script, things
+# should continue to work as you expect. And, of course, you can freely
+# overwrite any of the functions or variables defined here before
+# calling anything to customize them.
+
+EXIT_SUCCESS=0
+EXIT_FAILURE=1
+EXIT_MISMATCH=63  # $? = 63 is used to indicate version mismatch to missing.
+EXIT_SKIP=77	  # $? = 77 is used to indicate a skipped test to automake.
+
+# Allow overriding, eg assuming that you follow the convention of
+# putting '$debug_cmd' at the start of all your functions, you can get
+# bash to show function call trace with:
+#
+#    debug_cmd='eval echo "${FUNCNAME[0]} $*" >&2' bash your-script-name
+debug_cmd=${debug_cmd-":"}
+exit_cmd=:
+
+# By convention, finish your script with:
+#
+#    exit $exit_status
+#
+# so that you can set exit_status to non-zero if you want to indicate
+# something went wrong during execution without actually bailing out at
+# the point of failure.
+exit_status=$EXIT_SUCCESS
+
+# Work around backward compatibility issue on IRIX 6.5. On IRIX 6.4+, sh
+# is ksh but when the shell is invoked as "sh" and the current value of
+# the _XPG environment variable is not equal to 1 (one), the special
+# positional parameter $0, within a function call, is the name of the
+# function.
+progpath=$0
+
+# The name of this program.
+progname=`$ECHO "$progpath" |$SED "$sed_basename"`
+
+# Make sure we have an absolute progpath for reexecution:
+case $progpath in
+  [\\/]*|[A-Za-z]:\\*) ;;
+  *[\\/]*)
+     progdir=`$ECHO "$progpath" |$SED "$sed_dirname"`
+     progdir=`cd "$progdir" && pwd`
+     progpath=$progdir/$progname
+     ;;
+  *)
+     _G_IFS=$IFS
+     IFS=${PATH_SEPARATOR-:}
+     for progdir in $PATH; do
+       IFS=$_G_IFS
+       test -x "$progdir/$progname" && break
+     done
+     IFS=$_G_IFS
+     test -n "$progdir" || progdir=`pwd`
+     progpath=$progdir/$progname
+     ;;
+esac
+
+
+## ----------------- ##
+## Standard options. ##
+## ----------------- ##
+
+# The following options affect the operation of the functions defined
+# below, and should be set appropriately depending on run-time para-
+# meters passed on the command line.
+
+opt_dry_run=false
+opt_quiet=false
+opt_verbose=false
+
+# Categories 'all' and 'none' are always available.  Append any others
+# you will pass as the first argument to func_warning from your own
+# code.
+warning_categories=
+
+# By default, display warnings according to 'opt_warning_types'.  Set
+# 'warning_func'  to ':' to elide all warnings, or func_fatal_error to
+# treat the next displayed warning as a fatal error.
+warning_func=func_warn_and_continue
+
+# Set to 'all' to display all warnings, 'none' to suppress all
+# warnings, or a space delimited list of some subset of
+# 'warning_categories' to display only the listed warnings.
+opt_warning_types=all
+
+
+## -------------------- ##
+## Resource management. ##
+## -------------------- ##
+
+# This section contains definitions for functions that each ensure a
+# particular resource (a file, or a non-empty configuration variable for
+# example) is available, and if appropriate to extract default values
+# from pertinent package files. Call them using their associated
+# 'require_*' variable to ensure that they are executed, at most, once.
+#
+# It's entirely deliberate that calling these functions can set
+# variables that don't obey the namespace limitations obeyed by the rest
+# of this file, in order that that they be as useful as possible to
+# callers.
+
+
+# require_term_colors
+# -------------------
+# Allow display of bold text on terminals that support it.
+require_term_colors=func_require_term_colors
+func_require_term_colors ()
+{
+    $debug_cmd
+
+    test -t 1 && {
+      # COLORTERM and USE_ANSI_COLORS environment variables take
+      # precedence, because most terminfo databases neglect to describe
+      # whether color sequences are supported.
+      test -n "${COLORTERM+set}" && : ${USE_ANSI_COLORS="1"}
+
+      if test 1 = "$USE_ANSI_COLORS"; then
+        # Standard ANSI escape sequences
+        tc_reset='[0m'
+        tc_bold='[1m';   tc_standout='[7m'
+        tc_red='[31m';   tc_green='[32m'
+        tc_blue='[34m';  tc_cyan='[36m'
+      else
+        # Otherwise trust the terminfo database after all.
+        test -n "`tput sgr0 2>/dev/null`" && {
+          tc_reset=`tput sgr0`
+          test -n "`tput bold 2>/dev/null`" && tc_bold=`tput bold`
+          tc_standout=$tc_bold
+          test -n "`tput smso 2>/dev/null`" && tc_standout=`tput smso`
+          test -n "`tput setaf 1 2>/dev/null`" && tc_red=`tput setaf 1`
+          test -n "`tput setaf 2 2>/dev/null`" && tc_green=`tput setaf 2`
+          test -n "`tput setaf 4 2>/dev/null`" && tc_blue=`tput setaf 4`
+          test -n "`tput setaf 5 2>/dev/null`" && tc_cyan=`tput setaf 5`
+        }
+      fi
+    }
+
+    require_term_colors=:
+}
+
+
+## ----------------- ##
+## Function library. ##
+## ----------------- ##
+
+# This section contains a variety of useful functions to call in your
+# scripts. Take note of the portable wrappers for features provided by
+# some modern shells, which will fall back to slower equivalents on
+# less featureful shells.
+
+
+# func_append VAR VALUE
+# ---------------------
+# Append VALUE onto the existing contents of VAR.
+
+  # We should try to minimise forks, especially on Windows where they are
+  # unreasonably slow, so skip the feature probes when bash or zsh are
+  # being used:
+  if test set = "${BASH_VERSION+set}${ZSH_VERSION+set}"; then
+    : ${_G_HAVE_ARITH_OP="yes"}
+    : ${_G_HAVE_XSI_OPS="yes"}
+    # The += operator was introduced in bash 3.1
+    case $BASH_VERSION in
+      [12].* | 3.0 | 3.0*) ;;
+      *)
+        : ${_G_HAVE_PLUSEQ_OP="yes"}
+        ;;
+    esac
+  fi
+
+  # _G_HAVE_PLUSEQ_OP
+  # Can be empty, in which case the shell is probed, "yes" if += is
+  # useable or anything else if it does not work.
+  test -z "$_G_HAVE_PLUSEQ_OP" \
+    && (eval 'x=a; x+=" b"; test "a b" = "$x"') 2>/dev/null \
+    && _G_HAVE_PLUSEQ_OP=yes
+
+if test yes = "$_G_HAVE_PLUSEQ_OP"
+then
+  # This is an XSI compatible shell, allowing a faster implementation...
+  eval 'func_append ()
+  {
+    $debug_cmd
+
+    eval "$1+=\$2"
+  }'
+else
+  # ...otherwise fall back to using expr, which is often a shell builtin.
+  func_append ()
+  {
+    $debug_cmd
+
+    eval "$1=\$$1\$2"
+  }
+fi
+
+
+# func_append_quoted VAR VALUE
+# ----------------------------
+# Quote VALUE and append to the end of shell variable VAR, separated
+# by a space.
+if test yes = "$_G_HAVE_PLUSEQ_OP"; then
+  eval 'func_append_quoted ()
+  {
+    $debug_cmd
+
+    func_quote_arg pretty "$2"
+    eval "$1+=\\ \$func_quote_arg_result"
+  }'
+else
+  func_append_quoted ()
+  {
+    $debug_cmd
+
+    func_quote_arg pretty "$2"
+    eval "$1=\$$1\\ \$func_quote_arg_result"
+  }
+fi
+
+
+# func_append_uniq VAR VALUE
+# --------------------------
+# Append unique VALUE onto the existing contents of VAR, assuming
+# entries are delimited by the first character of VALUE.  For example:
+#
+#   func_append_uniq options " --another-option option-argument"
+#
+# will only append to $options if " --another-option option-argument "
+# is not already present somewhere in $options already (note spaces at
+# each end implied by leading space in second argument).
+func_append_uniq ()
+{
+    $debug_cmd
+
+    eval _G_current_value='`$ECHO $'$1'`'
+    _G_delim=`expr "$2" : '\(.\)'`
+
+    case $_G_delim$_G_current_value$_G_delim in
+      *"$2$_G_delim"*) ;;
+      *) func_append "$@" ;;
+    esac
+}
+
+
+# func_arith TERM...
+# ------------------
+# Set func_arith_result to the result of evaluating TERMs.
+  test -z "$_G_HAVE_ARITH_OP" \
+    && (eval 'test 2 = $(( 1 + 1 ))') 2>/dev/null \
+    && _G_HAVE_ARITH_OP=yes
+
+if test yes = "$_G_HAVE_ARITH_OP"; then
+  eval 'func_arith ()
+  {
+    $debug_cmd
+
+    func_arith_result=$(( $* ))
+  }'
+else
+  func_arith ()
+  {
+    $debug_cmd
+
+    func_arith_result=`expr "$@"`
+  }
+fi
+
+
+# func_basename FILE
+# ------------------
+# Set func_basename_result to FILE with everything up to and including
+# the last / stripped.
+if test yes = "$_G_HAVE_XSI_OPS"; then
+  # If this shell supports suffix pattern removal, then use it to avoid
+  # forking. Hide the definitions single quotes in case the shell chokes
+  # on unsupported syntax...
+  _b='func_basename_result=${1##*/}'
+  _d='case $1 in
+        */*) func_dirname_result=${1%/*}$2 ;;
+        *  ) func_dirname_result=$3        ;;
+      esac'
+
+else
+  # ...otherwise fall back to using sed.
+  _b='func_basename_result=`$ECHO "$1" |$SED "$sed_basename"`'
+  _d='func_dirname_result=`$ECHO "$1"  |$SED "$sed_dirname"`
+      if test "X$func_dirname_result" = "X$1"; then
+        func_dirname_result=$3
+      else
+        func_append func_dirname_result "$2"
+      fi'
+fi
+
+eval 'func_basename ()
+{
+    $debug_cmd
+
+    '"$_b"'
+}'
+
+
+# func_dirname FILE APPEND NONDIR_REPLACEMENT
+# -------------------------------------------
+# Compute the dirname of FILE.  If nonempty, add APPEND to the result,
+# otherwise set result to NONDIR_REPLACEMENT.
+eval 'func_dirname ()
+{
+    $debug_cmd
+
+    '"$_d"'
+}'
+
+
+# func_dirname_and_basename FILE APPEND NONDIR_REPLACEMENT
+# --------------------------------------------------------
+# Perform func_basename and func_dirname in a single function
+# call:
+#   dirname:  Compute the dirname of FILE.  If nonempty,
+#             add APPEND to the result, otherwise set result
+#             to NONDIR_REPLACEMENT.
+#             value returned in "$func_dirname_result"
+#   basename: Compute filename of FILE.
+#             value retuned in "$func_basename_result"
+# For efficiency, we do not delegate to the functions above but instead
+# duplicate the functionality here.
+eval 'func_dirname_and_basename ()
+{
+    $debug_cmd
+
+    '"$_b"'
+    '"$_d"'
+}'
+
+
+# func_echo ARG...
+# ----------------
+# Echo program name prefixed message.
+func_echo ()
+{
+    $debug_cmd
+
+    _G_message=$*
+
+    func_echo_IFS=$IFS
+    IFS=$nl
+    for _G_line in $_G_message; do
+      IFS=$func_echo_IFS
+      $ECHO "$progname: $_G_line"
+    done
+    IFS=$func_echo_IFS
+}
+
+
+# func_echo_all ARG...
+# --------------------
+# Invoke $ECHO with all args, space-separated.
+func_echo_all ()
+{
+    $ECHO "$*"
+}
+
+
+# func_echo_infix_1 INFIX ARG...
+# ------------------------------
+# Echo program name, followed by INFIX on the first line, with any
+# additional lines not showing INFIX.
+func_echo_infix_1 ()
+{
+    $debug_cmd
+
+    $require_term_colors
+
+    _G_infix=$1; shift
+    _G_indent=$_G_infix
+    _G_prefix="$progname: $_G_infix: "
+    _G_message=$*
+
+    # Strip color escape sequences before counting printable length
+    for _G_tc in "$tc_reset" "$tc_bold" "$tc_standout" "$tc_red" "$tc_green" "$tc_blue" "$tc_cyan"
+    do
+      test -n "$_G_tc" && {
+        _G_esc_tc=`$ECHO "$_G_tc" | $SED "$sed_make_literal_regex"`
+        _G_indent=`$ECHO "$_G_indent" | $SED "s|$_G_esc_tc||g"`
+      }
+    done
+    _G_indent="$progname: "`echo "$_G_indent" | $SED 's|.| |g'`"  " ## exclude from sc_prohibit_nested_quotes
+
+    func_echo_infix_1_IFS=$IFS
+    IFS=$nl
+    for _G_line in $_G_message; do
+      IFS=$func_echo_infix_1_IFS
+      $ECHO "$_G_prefix$tc_bold$_G_line$tc_reset" >&2
+      _G_prefix=$_G_indent
+    done
+    IFS=$func_echo_infix_1_IFS
+}
+
+
+# func_error ARG...
+# -----------------
+# Echo program name prefixed message to standard error.
+func_error ()
+{
+    $debug_cmd
+
+    $require_term_colors
+
+    func_echo_infix_1 "  $tc_standout${tc_red}error$tc_reset" "$*" >&2
+}
+
+
+# func_fatal_error ARG...
+# -----------------------
+# Echo program name prefixed message to standard error, and exit.
+func_fatal_error ()
+{
+    $debug_cmd
+
+    func_error "$*"
+    exit $EXIT_FAILURE
+}
+
+
+# func_grep EXPRESSION FILENAME
+# -----------------------------
+# Check whether EXPRESSION matches any line of FILENAME, without output.
+func_grep ()
+{
+    $debug_cmd
+
+    $GREP "$1" "$2" >/dev/null 2>&1
+}
+
+
+# func_len STRING
+# ---------------
+# Set func_len_result to the length of STRING. STRING may not
+# start with a hyphen.
+  test -z "$_G_HAVE_XSI_OPS" \
+    && (eval 'x=a/b/c;
+      test 5aa/bb/cc = "${#x}${x%%/*}${x%/*}${x#*/}${x##*/}"') 2>/dev/null \
+    && _G_HAVE_XSI_OPS=yes
+
+if test yes = "$_G_HAVE_XSI_OPS"; then
+  eval 'func_len ()
+  {
+    $debug_cmd
+
+    func_len_result=${#1}
+  }'
+else
+  func_len ()
+  {
+    $debug_cmd
+
+    func_len_result=`expr "$1" : ".*" 2>/dev/null || echo $max_cmd_len`
+  }
+fi
+
+
+# func_mkdir_p DIRECTORY-PATH
+# ---------------------------
+# Make sure the entire path to DIRECTORY-PATH is available.
+func_mkdir_p ()
+{
+    $debug_cmd
+
+    _G_directory_path=$1
+    _G_dir_list=
+
+    if test -n "$_G_directory_path" && test : != "$opt_dry_run"; then
+
+      # Protect directory names starting with '-'
+      case $_G_directory_path in
+        -*) _G_directory_path=./$_G_directory_path ;;
+      esac
+
+      # While some portion of DIR does not yet exist...
+      while test ! -d "$_G_directory_path"; do
+        # ...make a list in topmost first order.  Use a colon delimited
+	# list incase some portion of path contains whitespace.
+        _G_dir_list=$_G_directory_path:$_G_dir_list
+
+        # If the last portion added has no slash in it, the list is done
+        case $_G_directory_path in */*) ;; *) break ;; esac
+
+        # ...otherwise throw away the child directory and loop
+        _G_directory_path=`$ECHO "$_G_directory_path" | $SED -e "$sed_dirname"`
+      done
+      _G_dir_list=`$ECHO "$_G_dir_list" | $SED 's|:*$||'`
+
+      func_mkdir_p_IFS=$IFS; IFS=:
+      for _G_dir in $_G_dir_list; do
+	IFS=$func_mkdir_p_IFS
+        # mkdir can fail with a 'File exist' error if two processes
+        # try to create one of the directories concurrently.  Don't
+        # stop in that case!
+        $MKDIR "$_G_dir" 2>/dev/null || :
+      done
+      IFS=$func_mkdir_p_IFS
+
+      # Bail out if we (or some other process) failed to create a directory.
+      test -d "$_G_directory_path" || \
+        func_fatal_error "Failed to create '$1'"
+    fi
+}
+
+
+# func_mktempdir [BASENAME]
+# -------------------------
+# Make a temporary directory that won't clash with other running
+# libtool processes, and avoids race conditions if possible.  If
+# given, BASENAME is the basename for that directory.
+func_mktempdir ()
+{
+    $debug_cmd
+
+    _G_template=${TMPDIR-/tmp}/${1-$progname}
+
+    if test : = "$opt_dry_run"; then
+      # Return a directory name, but don't create it in dry-run mode
+      _G_tmpdir=$_G_template-$$
+    else
+
+      # If mktemp works, use that first and foremost
+      _G_tmpdir=`mktemp -d "$_G_template-XXXXXXXX" 2>/dev/null`
+
+      if test ! -d "$_G_tmpdir"; then
+        # Failing that, at least try and use $RANDOM to avoid a race
+        _G_tmpdir=$_G_template-${RANDOM-0}$$
+
+        func_mktempdir_umask=`umask`
+        umask 0077
+        $MKDIR "$_G_tmpdir"
+        umask $func_mktempdir_umask
+      fi
+
+      # If we're not in dry-run mode, bomb out on failure
+      test -d "$_G_tmpdir" || \
+        func_fatal_error "cannot create temporary directory '$_G_tmpdir'"
+    fi
+
+    $ECHO "$_G_tmpdir"
+}
+
+
+# func_normal_abspath PATH
+# ------------------------
+# Remove doubled-up and trailing slashes, "." path components,
+# and cancel out any ".." path components in PATH after making
+# it an absolute path.
+func_normal_abspath ()
+{
+    $debug_cmd
+
+    # These SED scripts presuppose an absolute path with a trailing slash.
+    _G_pathcar='s|^/\([^/]*\).*$|\1|'
+    _G_pathcdr='s|^/[^/]*||'
+    _G_removedotparts=':dotsl
+		s|/\./|/|g
+		t dotsl
+		s|/\.$|/|'
+    _G_collapseslashes='s|/\{1,\}|/|g'
+    _G_finalslash='s|/*$|/|'
+
+    # Start from root dir and reassemble the path.
+    func_normal_abspath_result=
+    func_normal_abspath_tpath=$1
+    func_normal_abspath_altnamespace=
+    case $func_normal_abspath_tpath in
+      "")
+        # Empty path, that just means $cwd.
+        func_stripname '' '/' "`pwd`"
+        func_normal_abspath_result=$func_stripname_result
+        return
+        ;;
+      # The next three entries are used to spot a run of precisely
+      # two leading slashes without using negated character classes;
+      # we take advantage of case's first-match behaviour.
+      ///*)
+        # Unusual form of absolute path, do nothing.
+        ;;
+      //*)
+        # Not necessarily an ordinary path; POSIX reserves leading '//'
+        # and for example Cygwin uses it to access remote file shares
+        # over CIFS/SMB, so we conserve a leading double slash if found.
+        func_normal_abspath_altnamespace=/
+        ;;
+      /*)
+        # Absolute path, do nothing.
+        ;;
+      *)
+        # Relative path, prepend $cwd.
+        func_normal_abspath_tpath=`pwd`/$func_normal_abspath_tpath
+        ;;
+    esac
+
+    # Cancel out all the simple stuff to save iterations.  We also want
+    # the path to end with a slash for ease of parsing, so make sure
+    # there is one (and only one) here.
+    func_normal_abspath_tpath=`$ECHO "$func_normal_abspath_tpath" | $SED \
+          -e "$_G_removedotparts" -e "$_G_collapseslashes" -e "$_G_finalslash"`
+    while :; do
+      # Processed it all yet?
+      if test / = "$func_normal_abspath_tpath"; then
+        # If we ascended to the root using ".." the result may be empty now.
+        if test -z "$func_normal_abspath_result"; then
+          func_normal_abspath_result=/
+        fi
+        break
+      fi
+      func_normal_abspath_tcomponent=`$ECHO "$func_normal_abspath_tpath" | $SED \
+          -e "$_G_pathcar"`
+      func_normal_abspath_tpath=`$ECHO "$func_normal_abspath_tpath" | $SED \
+          -e "$_G_pathcdr"`
+      # Figure out what to do with it
+      case $func_normal_abspath_tcomponent in
+        "")
+          # Trailing empty path component, ignore it.
+          ;;
+        ..)
+          # Parent dir; strip last assembled component from result.
+          func_dirname "$func_normal_abspath_result"
+          func_normal_abspath_result=$func_dirname_result
+          ;;
+        *)
+          # Actual path component, append it.
+          func_append func_normal_abspath_result "/$func_normal_abspath_tcomponent"
+          ;;
+      esac
+    done
+    # Restore leading double-slash if one was found on entry.
+    func_normal_abspath_result=$func_normal_abspath_altnamespace$func_normal_abspath_result
+}
+
+
+# func_notquiet ARG...
+# --------------------
+# Echo program name prefixed message only when not in quiet mode.
+func_notquiet ()
+{
+    $debug_cmd
+
+    $opt_quiet || func_echo ${1+"$@"}
+
+    # A bug in bash halts the script if the last line of a function
+    # fails when set -e is in force, so we need another command to
+    # work around that:
+    :
+}
+
+
+# func_relative_path SRCDIR DSTDIR
+# --------------------------------
+# Set func_relative_path_result to the relative path from SRCDIR to DSTDIR.
+func_relative_path ()
+{
+    $debug_cmd
+
+    func_relative_path_result=
+    func_normal_abspath "$1"
+    func_relative_path_tlibdir=$func_normal_abspath_result
+    func_normal_abspath "$2"
+    func_relative_path_tbindir=$func_normal_abspath_result
+
+    # Ascend the tree starting from libdir
+    while :; do
+      # check if we have found a prefix of bindir
+      case $func_relative_path_tbindir in
+        $func_relative_path_tlibdir)
+          # found an exact match
+          func_relative_path_tcancelled=
+          break
+          ;;
+        $func_relative_path_tlibdir*)
+          # found a matching prefix
+          func_stripname "$func_relative_path_tlibdir" '' "$func_relative_path_tbindir"
+          func_relative_path_tcancelled=$func_stripname_result
+          if test -z "$func_relative_path_result"; then
+            func_relative_path_result=.
+          fi
+          break
+          ;;
+        *)
+          func_dirname $func_relative_path_tlibdir
+          func_relative_path_tlibdir=$func_dirname_result
+          if test -z "$func_relative_path_tlibdir"; then
+            # Have to descend all the way to the root!
+            func_relative_path_result=../$func_relative_path_result
+            func_relative_path_tcancelled=$func_relative_path_tbindir
+            break
+          fi
+          func_relative_path_result=../$func_relative_path_result
+          ;;
+      esac
+    done
+
+    # Now calculate path; take care to avoid doubling-up slashes.
+    func_stripname '' '/' "$func_relative_path_result"
+    func_relative_path_result=$func_stripname_result
+    func_stripname '/' '/' "$func_relative_path_tcancelled"
+    if test -n "$func_stripname_result"; then
+      func_append func_relative_path_result "/$func_stripname_result"
+    fi
+
+    # Normalisation. If bindir is libdir, return '.' else relative path.
+    if test -n "$func_relative_path_result"; then
+      func_stripname './' '' "$func_relative_path_result"
+      func_relative_path_result=$func_stripname_result
+    fi
+
+    test -n "$func_relative_path_result" || func_relative_path_result=.
+
+    :
+}
+
+
+# func_quote_portable EVAL ARG
+# ----------------------------
+# Internal function to portably implement func_quote_arg.  Note that we still
+# keep attention to performance here so we as much as possible try to avoid
+# calling sed binary (so far O(N) complexity as long as func_append is O(1)).
+func_quote_portable ()
+{
+    $debug_cmd
+
+    $require_check_ifs_backslash
+
+    func_quote_portable_result=$2
+
+    # one-time-loop (easy break)
+    while true
+    do
+      if $1; then
+        func_quote_portable_result=`$ECHO "$2" | $SED \
+          -e "$sed_double_quote_subst" -e "$sed_double_backslash"`
+        break
+      fi
+
+      # Quote for eval.
+      case $func_quote_portable_result in
+        *[\\\`\"\$]*)
+          # Fallback to sed for $func_check_bs_ifs_broken=:, or when the string
+          # contains the shell wildcard characters.
+          case $check_ifs_backshlash_broken$func_quote_portable_result in
+            :*|*[\[\*\?]*)
+              func_quote_portable_result=`$ECHO "$func_quote_portable_result" \
+                  | $SED "$sed_quote_subst"`
+              break
+              ;;
+          esac
+
+          func_quote_portable_old_IFS=$IFS
+          for _G_char in '\' '`' '"' '$'
+          do
+            # STATE($1) PREV($2) SEPARATOR($3)
+            set start "" ""
+            func_quote_portable_result=dummy"$_G_char$func_quote_portable_result$_G_char"dummy
+            IFS=$_G_char
+            for _G_part in $func_quote_portable_result
+            do
+              case $1 in
+              quote)
+                func_append func_quote_portable_result "$3$2"
+                set quote "$_G_part" "\\$_G_char"
+                ;;
+              start)
+                set first "" ""
+                func_quote_portable_result=
+                ;;
+              first)
+                set quote "$_G_part" ""
+                ;;
+              esac
+            done
+          done
+          IFS=$func_quote_portable_old_IFS
+          ;;
+        *) ;;
+      esac
+      break
+    done
+
+    func_quote_portable_unquoted_result=$func_quote_portable_result
+    case $func_quote_portable_result in
+      # double-quote args containing shell metacharacters to delay
+      # word splitting, command substitution and variable expansion
+      # for a subsequent eval.
+      # many bourne shells cannot handle close brackets correctly
+      # in scan sets, so we specify it separately.
+      *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
+        func_quote_portable_result=\"$func_quote_portable_result\"
+        ;;
+    esac
+}
+
+
+# func_quotefast_eval ARG
+# -----------------------
+# Quote one ARG (internal).  This is equivalent to 'func_quote_arg eval ARG',
+# but optimized for speed.  Result is stored in $func_quotefast_eval.
+if test xyes = `(x=; printf -v x %q yes; echo x"$x") 2>/dev/null`; then
+  printf -v _GL_test_printf_tilde %q '~'
+  if test '\~' = "$_GL_test_printf_tilde"; then
+    func_quotefast_eval ()
+    {
+      printf -v func_quotefast_eval_result %q "$1"
+    }
+  else
+    # Broken older Bash implementations.  Make those faster too if possible.
+    func_quotefast_eval ()
+    {
+      case $1 in
+        '~'*)
+          func_quote_portable false "$1"
+          func_quotefast_eval_result=$func_quote_portable_result
+          ;;
+        *)
+          printf -v func_quotefast_eval_result %q "$1"
+          ;;
+      esac
+    }
+  fi
+else
+  func_quotefast_eval ()
+  {
+    func_quote_portable false "$1"
+    func_quotefast_eval_result=$func_quote_portable_result
+  }
+fi
+
+
+# func_quote_arg MODEs ARG
+# ------------------------
+# Quote one ARG to be evaled later.  MODEs argument may contain zero or more
+# specifiers listed below separated by ',' character.  This function returns two
+# values:
+#   i) func_quote_arg_result
+#      double-quoted (when needed), suitable for a subsequent eval
+#  ii) func_quote_arg_unquoted_result
+#      has all characters that are still active within double
+#      quotes backslashified.  Available only if 'unquoted' is specified.
+#
+# Available modes:
+# ----------------
+# 'eval' (default)
+#       - escape shell special characters
+# 'expand'
+#       - the same as 'eval';  but do not quote variable references
+# 'pretty'
+#       - request aesthetic output, i.e. '"a b"' instead of 'a\ b'.  This might
+#         be used later in func_quote to get output like: 'echo "a b"' instead
+#         of 'echo a\ b'.  This is slower than default on some shells.
+# 'unquoted'
+#       - produce also $func_quote_arg_unquoted_result which does not contain
+#         wrapping double-quotes.
+#
+# Examples for 'func_quote_arg pretty,unquoted string':
+#
+#   string      | *_result              | *_unquoted_result
+#   ------------+-----------------------+-------------------
+#   "           | \"                    | \"
+#   a b         | "a b"                 | a b
+#   "a b"       | "\"a b\""             | \"a b\"
+#   *           | "*"                   | *
+#   z="${x-$y}" | "z=\"\${x-\$y}\""     | z=\"\${x-\$y}\"
+#
+# Examples for 'func_quote_arg pretty,unquoted,expand string':
+#
+#   string        |   *_result          |  *_unquoted_result
+#   --------------+---------------------+--------------------
+#   z="${x-$y}"   | "z=\"${x-$y}\""     | z=\"${x-$y}\"
+func_quote_arg ()
+{
+    _G_quote_expand=false
+    case ,$1, in
+      *,expand,*)
+        _G_quote_expand=:
+        ;;
+    esac
+
+    case ,$1, in
+      *,pretty,*|*,expand,*|*,unquoted,*)
+        func_quote_portable $_G_quote_expand "$2"
+        func_quote_arg_result=$func_quote_portable_result
+        func_quote_arg_unquoted_result=$func_quote_portable_unquoted_result
+        ;;
+      *)
+        # Faster quote-for-eval for some shells.
+        func_quotefast_eval "$2"
+        func_quote_arg_result=$func_quotefast_eval_result
+        ;;
+    esac
+}
+
+
+# func_quote MODEs ARGs...
+# ------------------------
+# Quote all ARGs to be evaled later and join them into single command.  See
+# func_quote_arg's description for more info.
+func_quote ()
+{
+    $debug_cmd
+    _G_func_quote_mode=$1 ; shift
+    func_quote_result=
+    while test 0 -lt $#; do
+      func_quote_arg "$_G_func_quote_mode" "$1"
+      if test -n "$func_quote_result"; then
+        func_append func_quote_result " $func_quote_arg_result"
+      else
+        func_append func_quote_result "$func_quote_arg_result"
+      fi
+      shift
+    done
+}
+
+
+# func_stripname PREFIX SUFFIX NAME
+# ---------------------------------
+# strip PREFIX and SUFFIX from NAME, and store in func_stripname_result.
+# PREFIX and SUFFIX must not contain globbing or regex special
+# characters, hashes, percent signs, but SUFFIX may contain a leading
+# dot (in which case that matches only a dot).
+if test yes = "$_G_HAVE_XSI_OPS"; then
+  eval 'func_stripname ()
+  {
+    $debug_cmd
+
+    # pdksh 5.2.14 does not do ${X%$Y} correctly if both X and Y are
+    # positional parameters, so assign one to ordinary variable first.
+    func_stripname_result=$3
+    func_stripname_result=${func_stripname_result#"$1"}
+    func_stripname_result=${func_stripname_result%"$2"}
+  }'
+else
+  func_stripname ()
+  {
+    $debug_cmd
+
+    case $2 in
+      .*) func_stripname_result=`$ECHO "$3" | $SED -e "s%^$1%%" -e "s%\\\\$2\$%%"`;;
+      *)  func_stripname_result=`$ECHO "$3" | $SED -e "s%^$1%%" -e "s%$2\$%%"`;;
+    esac
+  }
+fi
+
+
+# func_show_eval CMD [FAIL_EXP]
+# -----------------------------
+# Unless opt_quiet is true, then output CMD.  Then, if opt_dryrun is
+# not true, evaluate CMD.  If the evaluation of CMD fails, and FAIL_EXP
+# is given, then evaluate it.
+func_show_eval ()
+{
+    $debug_cmd
+
+    _G_cmd=$1
+    _G_fail_exp=${2-':'}
+
+    func_quote_arg pretty,expand "$_G_cmd"
+    eval "func_notquiet $func_quote_arg_result"
+
+    $opt_dry_run || {
+      eval "$_G_cmd"
+      _G_status=$?
+      if test 0 -ne "$_G_status"; then
+	eval "(exit $_G_status); $_G_fail_exp"
+      fi
+    }
+}
+
+
+# func_show_eval_locale CMD [FAIL_EXP]
+# ------------------------------------
+# Unless opt_quiet is true, then output CMD.  Then, if opt_dryrun is
+# not true, evaluate CMD.  If the evaluation of CMD fails, and FAIL_EXP
+# is given, then evaluate it.  Use the saved locale for evaluation.
+func_show_eval_locale ()
+{
+    $debug_cmd
+
+    _G_cmd=$1
+    _G_fail_exp=${2-':'}
+
+    $opt_quiet || {
+      func_quote_arg expand,pretty "$_G_cmd"
+      eval "func_echo $func_quote_arg_result"
+    }
+
+    $opt_dry_run || {
+      eval "$_G_user_locale
+	    $_G_cmd"
+      _G_status=$?
+      eval "$_G_safe_locale"
+      if test 0 -ne "$_G_status"; then
+	eval "(exit $_G_status); $_G_fail_exp"
+      fi
+    }
+}
+
+
+# func_tr_sh
+# ----------
+# Turn $1 into a string suitable for a shell variable name.
+# Result is stored in $func_tr_sh_result.  All characters
+# not in the set a-zA-Z0-9_ are replaced with '_'. Further,
+# if $1 begins with a digit, a '_' is prepended as well.
+func_tr_sh ()
+{
+    $debug_cmd
+
+    case $1 in
+    [0-9]* | *[!a-zA-Z0-9_]*)
+      func_tr_sh_result=`$ECHO "$1" | $SED -e 's/^\([0-9]\)/_\1/' -e 's/[^a-zA-Z0-9_]/_/g'`
+      ;;
+    * )
+      func_tr_sh_result=$1
+      ;;
+    esac
+}
+
+
+# func_verbose ARG...
+# -------------------
+# Echo program name prefixed message in verbose mode only.
+func_verbose ()
+{
+    $debug_cmd
+
+    $opt_verbose && func_echo "$*"
+
+    :
+}
+
+
+# func_warn_and_continue ARG...
+# -----------------------------
+# Echo program name prefixed warning message to standard error.
+func_warn_and_continue ()
+{
+    $debug_cmd
+
+    $require_term_colors
+
+    func_echo_infix_1 "${tc_red}warning$tc_reset" "$*" >&2
+}
+
+
+# func_warning CATEGORY ARG...
+# ----------------------------
+# Echo program name prefixed warning message to standard error. Warning
+# messages can be filtered according to CATEGORY, where this function
+# elides messages where CATEGORY is not listed in the global variable
+# 'opt_warning_types'.
+func_warning ()
+{
+    $debug_cmd
+
+    # CATEGORY must be in the warning_categories list!
+    case " $warning_categories " in
+      *" $1 "*) ;;
+      *) func_internal_error "invalid warning category '$1'" ;;
+    esac
+
+    _G_category=$1
+    shift
+
+    case " $opt_warning_types " in
+      *" $_G_category "*) $warning_func ${1+"$@"} ;;
+    esac
+}
+
+
+# func_sort_ver VER1 VER2
+# -----------------------
+# 'sort -V' is not generally available.
+# Note this deviates from the version comparison in automake
+# in that it treats 1.5 < 1.5.0, and treats 1.4.4a < 1.4-p3a
+# but this should suffice as we won't be specifying old
+# version formats or redundant trailing .0 in bootstrap.conf.
+# If we did want full compatibility then we should probably
+# use m4_version_compare from autoconf.
+func_sort_ver ()
+{
+    $debug_cmd
+
+    printf '%s\n%s\n' "$1" "$2" \
+      | sort -t. -k 1,1n -k 2,2n -k 3,3n -k 4,4n -k 5,5n -k 6,6n -k 7,7n -k 8,8n -k 9,9n
+}
+
+# func_lt_ver PREV CURR
+# ---------------------
+# Return true if PREV and CURR are in the correct order according to
+# func_sort_ver, otherwise false.  Use it like this:
+#
+#  func_lt_ver "$prev_ver" "$proposed_ver" || func_fatal_error "..."
+func_lt_ver ()
+{
+    $debug_cmd
+
+    test "x$1" = x`func_sort_ver "$1" "$2" | $SED 1q`
+}
+
+
+# Local variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-pattern: "10/scriptversion=%:y-%02m-%02d.%02H; # UTC"
+# time-stamp-time-zone: "UTC"
+# End:
+#! /bin/sh
+
+# A portable, pluggable option parser for Bourne shell.
+# Written by Gary V. Vaughan, 2010
+
+# This is free software.  There is NO warranty; not even for
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# Copyright (C) 2010-2019, 2021 Bootstrap Authors
+#
+# This file is dual licensed under the terms of the MIT license
+# <https://opensource.org/license/MIT>, and GPL version 2 or later
+# <http://www.gnu.org/licenses/gpl-2.0.html>.  You must apply one of
+# these licenses when using or redistributing this software or any of
+# the files within it.  See the URLs above, or the file `LICENSE`
+# included in the Bootstrap distribution for the full license texts.
+
+# Please report bugs or propose patches to:
+# <https://github.com/gnulib-modules/bootstrap/issues>
+
+# Set a version string for this script.
+scriptversion=2019-02-19.15; # UTC
+
+
+## ------ ##
+## Usage. ##
+## ------ ##
+
+# This file is a library for parsing options in your shell scripts along
+# with assorted other useful supporting features that you can make use
+# of too.
+#
+# For the simplest scripts you might need only:
+#
+#   #!/bin/sh
+#   . relative/path/to/funclib.sh
+#   . relative/path/to/options-parser
+#   scriptversion=1.0
+#   func_options ${1+"$@"}
+#   eval set dummy "$func_options_result"; shift
+#   ...rest of your script...
+#
+# In order for the '--version' option to work, you will need to have a
+# suitably formatted comment like the one at the top of this file
+# starting with '# Written by ' and ending with '# Copyright'.
+#
+# For '-h' and '--help' to work, you will also need a one line
+# description of your script's purpose in a comment directly above the
+# '# Written by ' line, like the one at the top of this file.
+#
+# The default options also support '--debug', which will turn on shell
+# execution tracing (see the comment above debug_cmd below for another
+# use), and '--verbose' and the func_verbose function to allow your script
+# to display verbose messages only when your user has specified
+# '--verbose'.
+#
+# After sourcing this file, you can plug in processing for additional
+# options by amending the variables from the 'Configuration' section
+# below, and following the instructions in the 'Option parsing'
+# section further down.
+
+## -------------- ##
+## Configuration. ##
+## -------------- ##
+
+# You should override these variables in your script after sourcing this
+# file so that they reflect the customisations you have added to the
+# option parser.
+
+# The usage line for option parsing errors and the start of '-h' and
+# '--help' output messages. You can embed shell variables for delayed
+# expansion at the time the message is displayed, but you will need to
+# quote other shell meta-characters carefully to prevent them being
+# expanded when the contents are evaled.
+usage='$progpath [OPTION]...'
+
+# Short help message in response to '-h' and '--help'.  Add to this or
+# override it after sourcing this library to reflect the full set of
+# options your script accepts.
+usage_message="\
+       --debug        enable verbose shell tracing
+   -W, --warnings=CATEGORY
+                      report the warnings falling in CATEGORY [all]
+   -v, --verbose      verbosely report processing
+       --version      print version information and exit
+   -h, --help         print short or long help message and exit
+"
+
+# Additional text appended to 'usage_message' in response to '--help'.
+long_help_message="
+Warning categories include:
+       'all'          show all warnings
+       'none'         turn off all the warnings
+       'error'        warnings are treated as fatal errors"
+
+# Help message printed before fatal option parsing errors.
+fatal_help="Try '\$progname --help' for more information."
+
+
+
+## ------------------------- ##
+## Hook function management. ##
+## ------------------------- ##
+
+# This section contains functions for adding, removing, and running hooks
+# in the main code.  A hook is just a list of function names that can be
+# run in order later on.
+
+# func_hookable FUNC_NAME
+# -----------------------
+# Declare that FUNC_NAME will run hooks added with
+# 'func_add_hook FUNC_NAME ...'.
+func_hookable ()
+{
+    $debug_cmd
+
+    func_append hookable_fns " $1"
+}
+
+
+# func_add_hook FUNC_NAME HOOK_FUNC
+# ---------------------------------
+# Request that FUNC_NAME call HOOK_FUNC before it returns.  FUNC_NAME must
+# first have been declared "hookable" by a call to 'func_hookable'.
+func_add_hook ()
+{
+    $debug_cmd
+
+    case " $hookable_fns " in
+      *" $1 "*) ;;
+      *) func_fatal_error "'$1' does not accept hook functions." ;;
+    esac
+
+    eval func_append ${1}_hooks '" $2"'
+}
+
+
+# func_remove_hook FUNC_NAME HOOK_FUNC
+# ------------------------------------
+# Remove HOOK_FUNC from the list of hook functions to be called by
+# FUNC_NAME.
+func_remove_hook ()
+{
+    $debug_cmd
+
+    eval ${1}_hooks='`$ECHO "\$'$1'_hooks" |$SED "s| '$2'||"`'
+}
+
+
+# func_propagate_result FUNC_NAME_A FUNC_NAME_B
+# ---------------------------------------------
+# If the *_result variable of FUNC_NAME_A _is set_, assign its value to
+# *_result variable of FUNC_NAME_B.
+func_propagate_result ()
+{
+    $debug_cmd
+
+    func_propagate_result_result=:
+    if eval "test \"\${${1}_result+set}\" = set"
+    then
+      eval "${2}_result=\$${1}_result"
+    else
+      func_propagate_result_result=false
+    fi
+}
+
+
+# func_run_hooks FUNC_NAME [ARG]...
+# ---------------------------------
+# Run all hook functions registered to FUNC_NAME.
+# It's assumed that the list of hook functions contains nothing more
+# than a whitespace-delimited list of legal shell function names, and
+# no effort is wasted trying to catch shell meta-characters or preserve
+# whitespace.
+func_run_hooks ()
+{
+    $debug_cmd
+
+    case " $hookable_fns " in
+      *" $1 "*) ;;
+      *) func_fatal_error "'$1' does not support hook functions." ;;
+    esac
+
+    eval _G_hook_fns=\$$1_hooks; shift
+
+    for _G_hook in $_G_hook_fns; do
+      func_unset "${_G_hook}_result"
+      eval $_G_hook '${1+"$@"}'
+      func_propagate_result $_G_hook func_run_hooks
+      if $func_propagate_result_result; then
+        eval set dummy "$func_run_hooks_result"; shift
+      fi
+    done
+}
+
+
+
+## --------------- ##
+## Option parsing. ##
+## --------------- ##
+
+# In order to add your own option parsing hooks, you must accept the
+# full positional parameter list from your hook function.  You may remove
+# or edit any options that you action, and then pass back the remaining
+# unprocessed options in '<hooked_function_name>_result', escaped
+# suitably for 'eval'.
+#
+# The '<hooked_function_name>_result' variable is automatically unset
+# before your hook gets called; for best performance, only set the
+# *_result variable when necessary (i.e. don't call the 'func_quote'
+# function unnecessarily because it can be an expensive operation on some
+# machines).
+#
+# Like this:
+#
+#    my_options_prep ()
+#    {
+#        $debug_cmd
+#
+#        # Extend the existing usage message.
+#        usage_message=$usage_message'
+#      -s, --silent       don'\''t print informational messages
+#    '
+#        # No change in '$@' (ignored completely by this hook).  Leave
+#        # my_options_prep_result variable intact.
+#    }
+#    func_add_hook func_options_prep my_options_prep
+#
+#
+#    my_silent_option ()
+#    {
+#        $debug_cmd
+#
+#        args_changed=false
+#
+#        # Note that, for efficiency, we parse as many options as we can
+#        # recognise in a loop before passing the remainder back to the
+#        # caller on the first unrecognised argument we encounter.
+#        while test $# -gt 0; do
+#          opt=$1; shift
+#          case $opt in
+#            --silent|-s) opt_silent=:
+#                         args_changed=:
+#                         ;;
+#            # Separate non-argument short options:
+#            -s*)         func_split_short_opt "$_G_opt"
+#                         set dummy "$func_split_short_opt_name" \
+#                             "-$func_split_short_opt_arg" ${1+"$@"}
+#                         shift
+#                         args_changed=:
+#                         ;;
+#            *)           # Make sure the first unrecognised option "$_G_opt"
+#                         # is added back to "$@" in case we need it later,
+#                         # if $args_changed was set to 'true'.
+#                         set dummy "$_G_opt" ${1+"$@"}; shift; break ;;
+#          esac
+#        done
+#
+#        # Only call 'func_quote' here if we processed at least one argument.
+#        if $args_changed; then
+#          func_quote eval ${1+"$@"}
+#          my_silent_option_result=$func_quote_result
+#        fi
+#    }
+#    func_add_hook func_parse_options my_silent_option
+#
+#
+#    my_option_validation ()
+#    {
+#        $debug_cmd
+#
+#        $opt_silent && $opt_verbose && func_fatal_help "\
+#    '--silent' and '--verbose' options are mutually exclusive."
+#    }
+#    func_add_hook func_validate_options my_option_validation
+#
+# You'll also need to manually amend $usage_message to reflect the extra
+# options you parse.  It's preferable to append if you can, so that
+# multiple option parsing hooks can be added safely.
+
+
+# func_options_finish [ARG]...
+# ----------------------------
+# Finishing the option parse loop (call 'func_options' hooks ATM).
+func_options_finish ()
+{
+    $debug_cmd
+
+    func_run_hooks func_options ${1+"$@"}
+    func_propagate_result func_run_hooks func_options_finish
+}
+
+
+# func_options [ARG]...
+# ---------------------
+# All the functions called inside func_options are hookable. See the
+# individual implementations for details.
+func_hookable func_options
+func_options ()
+{
+    $debug_cmd
+
+    _G_options_quoted=false
+
+    for my_func in options_prep parse_options validate_options options_finish
+    do
+      func_unset func_${my_func}_result
+      func_unset func_run_hooks_result
+      eval func_$my_func '${1+"$@"}'
+      func_propagate_result func_$my_func func_options
+      if $func_propagate_result_result; then
+        eval set dummy "$func_options_result"; shift
+        _G_options_quoted=:
+      fi
+    done
+
+    $_G_options_quoted || {
+      # As we (func_options) are top-level options-parser function and
+      # nobody quoted "$@" for us yet, we need to do it explicitly for
+      # caller.
+      func_quote eval ${1+"$@"}
+      func_options_result=$func_quote_result
+    }
+}
+
+
+# func_options_prep [ARG]...
+# --------------------------
+# All initialisations required before starting the option parse loop.
+# Note that when calling hook functions, we pass through the list of
+# positional parameters.  If a hook function modifies that list, and
+# needs to propagate that back to rest of this script, then the complete
+# modified list must be put in 'func_run_hooks_result' before returning.
+func_hookable func_options_prep
+func_options_prep ()
+{
+    $debug_cmd
+
+    # Option defaults:
+    opt_verbose=false
+    opt_warning_types=
+
+    func_run_hooks func_options_prep ${1+"$@"}
+    func_propagate_result func_run_hooks func_options_prep
+}
+
+
+# func_parse_options [ARG]...
+# ---------------------------
+# The main option parsing loop.
+func_hookable func_parse_options
+func_parse_options ()
+{
+    $debug_cmd
+
+    _G_parse_options_requote=false
+    # this just eases exit handling
+    while test $# -gt 0; do
+      # Defer to hook functions for initial option parsing, so they
+      # get priority in the event of reusing an option name.
+      func_run_hooks func_parse_options ${1+"$@"}
+      func_propagate_result func_run_hooks func_parse_options
+      if $func_propagate_result_result; then
+        eval set dummy "$func_parse_options_result"; shift
+        # Even though we may have changed "$@", we passed the "$@" array
+        # down into the hook and it quoted it for us (because we are in
+        # this if-branch).  No need to quote it again.
+        _G_parse_options_requote=false
+      fi
+
+      # Break out of the loop if we already parsed every option.
+      test $# -gt 0 || break
+
+      # We expect that one of the options parsed in this function matches
+      # and thus we remove _G_opt from "$@" and need to re-quote.
+      _G_match_parse_options=:
+      _G_opt=$1
+      shift
+      case $_G_opt in
+        --debug|-x)   debug_cmd='set -x'
+                      func_echo "enabling shell trace mode" >&2
+                      $debug_cmd
+                      ;;
+
+        --no-warnings|--no-warning|--no-warn)
+                      set dummy --warnings none ${1+"$@"}
+                      shift
+		      ;;
+
+        --warnings|--warning|-W)
+                      if test $# = 0 && func_missing_arg $_G_opt; then
+                        _G_parse_options_requote=:
+                        break
+                      fi
+                      case " $warning_categories $1" in
+                        *" $1 "*)
+                          # trailing space prevents matching last $1 above
+                          func_append_uniq opt_warning_types " $1"
+                          ;;
+                        *all)
+                          opt_warning_types=$warning_categories
+                          ;;
+                        *none)
+                          opt_warning_types=none
+                          warning_func=:
+                          ;;
+                        *error)
+                          opt_warning_types=$warning_categories
+                          warning_func=func_fatal_error
+                          ;;
+                        *)
+                          func_fatal_error \
+                             "unsupported warning category: '$1'"
+                          ;;
+                      esac
+                      shift
+                      ;;
+
+        --verbose|-v) opt_verbose=: ;;
+        --version)    func_version ;;
+        -\?|-h)       func_usage ;;
+        --help)       func_help ;;
+
+	# Separate optargs to long options (plugins may need this):
+	--*=*)        func_split_equals "$_G_opt"
+	              set dummy "$func_split_equals_lhs" \
+                          "$func_split_equals_rhs" ${1+"$@"}
+                      shift
+                      ;;
+
+       # Separate optargs to short options:
+        -W*)
+                      func_split_short_opt "$_G_opt"
+                      set dummy "$func_split_short_opt_name" \
+                          "$func_split_short_opt_arg" ${1+"$@"}
+                      shift
+                      ;;
+
+        # Separate non-argument short options:
+        -\?*|-h*|-v*|-x*)
+                      func_split_short_opt "$_G_opt"
+                      set dummy "$func_split_short_opt_name" \
+                          "-$func_split_short_opt_arg" ${1+"$@"}
+                      shift
+                      ;;
+
+        --)           _G_parse_options_requote=: ; break ;;
+        -*)           func_fatal_help "unrecognised option: '$_G_opt'" ;;
+        *)            set dummy "$_G_opt" ${1+"$@"}; shift
+                      _G_match_parse_options=false
+                      break
+                      ;;
+      esac
+
+      if $_G_match_parse_options; then
+        _G_parse_options_requote=:
+      fi
+    done
+
+    if $_G_parse_options_requote; then
+      # save modified positional parameters for caller
+      func_quote eval ${1+"$@"}
+      func_parse_options_result=$func_quote_result
+    fi
+}
+
+
+# func_validate_options [ARG]...
+# ------------------------------
+# Perform any sanity checks on option settings and/or unconsumed
+# arguments.
+func_hookable func_validate_options
+func_validate_options ()
+{
+    $debug_cmd
+
+    # Display all warnings if -W was not given.
+    test -n "$opt_warning_types" || opt_warning_types=" $warning_categories"
+
+    func_run_hooks func_validate_options ${1+"$@"}
+    func_propagate_result func_run_hooks func_validate_options
+
+    # Bail if the options were screwed!
+    $exit_cmd $EXIT_FAILURE
+}
+
+
+
+## ----------------- ##
+## Helper functions. ##
+## ----------------- ##
+
+# This section contains the helper functions used by the rest of the
+# hookable option parser framework in ascii-betical order.
+
+
+# func_fatal_help ARG...
+# ----------------------
+# Echo program name prefixed message to standard error, followed by
+# a help hint, and exit.
+func_fatal_help ()
+{
+    $debug_cmd
+
+    eval \$ECHO \""Usage: $usage"\"
+    eval \$ECHO \""$fatal_help"\"
+    func_error ${1+"$@"}
+    exit $EXIT_FAILURE
+}
+
+
+# func_help
+# ---------
+# Echo long help message to standard output and exit.
+func_help ()
+{
+    $debug_cmd
+
+    func_usage_message
+    $ECHO "$long_help_message"
+    exit 0
+}
+
+
+# func_missing_arg ARGNAME
+# ------------------------
+# Echo program name prefixed message to standard error and set global
+# exit_cmd.
+func_missing_arg ()
+{
+    $debug_cmd
+
+    func_error "Missing argument for '$1'."
+    exit_cmd=exit
+}
+
+
+# func_split_equals STRING
+# ------------------------
+# Set func_split_equals_lhs and func_split_equals_rhs shell variables
+# after splitting STRING at the '=' sign.
+test -z "$_G_HAVE_XSI_OPS" \
+    && (eval 'x=a/b/c;
+      test 5aa/bb/cc = "${#x}${x%%/*}${x%/*}${x#*/}${x##*/}"') 2>/dev/null \
+    && _G_HAVE_XSI_OPS=yes
+
+if test yes = "$_G_HAVE_XSI_OPS"
+then
+  # This is an XSI compatible shell, allowing a faster implementation...
+  eval 'func_split_equals ()
+  {
+      $debug_cmd
+
+      func_split_equals_lhs=${1%%=*}
+      func_split_equals_rhs=${1#*=}
+      if test "x$func_split_equals_lhs" = "x$1"; then
+        func_split_equals_rhs=
+      fi
+  }'
+else
+  # ...otherwise fall back to using expr, which is often a shell builtin.
+  func_split_equals ()
+  {
+      $debug_cmd
+
+      func_split_equals_lhs=`expr "x$1" : 'x\([^=]*\)'`
+      func_split_equals_rhs=
+      test "x$func_split_equals_lhs=" = "x$1" \
+        || func_split_equals_rhs=`expr "x$1" : 'x[^=]*=\(.*\)$'`
+  }
+fi #func_split_equals
+
+
+# func_split_short_opt SHORTOPT
+# -----------------------------
+# Set func_split_short_opt_name and func_split_short_opt_arg shell
+# variables after splitting SHORTOPT after the 2nd character.
+if test yes = "$_G_HAVE_XSI_OPS"
+then
+  # This is an XSI compatible shell, allowing a faster implementation...
+  eval 'func_split_short_opt ()
+  {
+      $debug_cmd
+
+      func_split_short_opt_arg=${1#??}
+      func_split_short_opt_name=${1%"$func_split_short_opt_arg"}
+  }'
+else
+  # ...otherwise fall back to using expr, which is often a shell builtin.
+  func_split_short_opt ()
+  {
+      $debug_cmd
+
+      func_split_short_opt_name=`expr "x$1" : 'x\(-.\)'`
+      func_split_short_opt_arg=`expr "x$1" : 'x-.\(.*\)$'`
+  }
+fi #func_split_short_opt
+
+
+# func_usage
+# ----------
+# Echo short help message to standard output and exit.
+func_usage ()
+{
+    $debug_cmd
+
+    func_usage_message
+    $ECHO "Run '$progname --help |${PAGER-more}' for full usage"
+    exit 0
+}
+
+
+# func_usage_message
+# ------------------
+# Echo short help message to standard output.
+func_usage_message ()
+{
+    $debug_cmd
+
+    eval \$ECHO \""Usage: $usage"\"
+    echo
+    $SED -n 's|^# ||
+        /^Written by/{
+          x;p;x
+        }
+	h
+	/^Written by/q' < "$progpath"
+    echo
+    eval \$ECHO \""$usage_message"\"
+}
+
+
+# func_version
+# ------------
+# Echo version message to standard output and exit.
+# The version message is extracted from the calling file's header
+# comments, with leading '# ' stripped:
+#   1. First display the progname and version
+#   2. Followed by the header comment line matching  /^# Written by /
+#   3. Then a blank line followed by the first following line matching
+#      /^# Copyright /
+#   4. Immediately followed by any lines between the previous matches,
+#      except lines preceding the intervening completely blank line.
+# For example, see the header comments of this file.
+func_version ()
+{
+    $debug_cmd
+
+    printf '%s\n' "$progname $scriptversion"
+    $SED -n '
+        /^# Written by /!b
+        s|^# ||; p; n
+
+        :fwd2blnk
+        /./ {
+          n
+          b fwd2blnk
+        }
+        p; n
+
+        :holdwrnt
+        s|^# ||
+        s|^# *$||
+        /^Copyright /!{
+          /./H
+          n
+          b holdwrnt
+        }
+
+        s|\((C)\)[ 0-9,-]*[ ,-]\([1-9][0-9]* \)|\1 \2|
+        G
+        s|\(\n\)\n*|\1|g
+        p; q' < "$progpath"
+
+    exit $?
+}
+
+
+# Local variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-pattern: "30/scriptversion=%:y-%02m-%02d.%02H; # UTC"
+# time-stamp-time-zone: "UTC"
+# End:
+
+# Set a version string.
+scriptversion='(GNU libtool) 2.4.7'
+
+
+# func_echo ARG...
+# ----------------
+# Libtool also displays the current mode in messages, so override
+# funclib.sh func_echo with this custom definition.
+func_echo ()
+{
+    $debug_cmd
+
+    _G_message=$*
+
+    func_echo_IFS=$IFS
+    IFS=$nl
+    for _G_line in $_G_message; do
+      IFS=$func_echo_IFS
+      $ECHO "$progname${opt_mode+: $opt_mode}: $_G_line"
+    done
+    IFS=$func_echo_IFS
+}
+
+
+# func_warning ARG...
+# -------------------
+# Libtool warnings are not categorized, so override funclib.sh
+# func_warning with this simpler definition.
+func_warning ()
+{
+    $debug_cmd
+
+    $warning_func ${1+"$@"}
+}
+
+
+## ---------------- ##
+## Options parsing. ##
+## ---------------- ##
+
+# Hook in the functions to make sure our own options are parsed during
+# the option parsing loop.
+
+usage='$progpath [OPTION]... [MODE-ARG]...'
+
+# Short help message in response to '-h'.
+usage_message="Options:
+       --config             show all configuration variables
+       --debug              enable verbose shell tracing
+   -n, --dry-run            display commands without modifying any files
+       --features           display basic configuration information and exit
+       --mode=MODE          use operation mode MODE
+       --no-warnings        equivalent to '-Wnone'
+       --preserve-dup-deps  don't remove duplicate dependency libraries
+       --quiet, --silent    don't print informational messages
+       --tag=TAG            use configuration variables from tag TAG
+   -v, --verbose            print more informational messages than default
+       --version            print version information
+   -W, --warnings=CATEGORY  report the warnings falling in CATEGORY [all]
+   -h, --help, --help-all   print short, long, or detailed help message
+"
+
+# Additional text appended to 'usage_message' in response to '--help'.
+func_help ()
+{
+    $debug_cmd
+
+    func_usage_message
+    $ECHO "$long_help_message
+
+MODE must be one of the following:
+
+       clean           remove files from the build directory
+       compile         compile a source file into a libtool object
+       execute         automatically set library path, then run a program
+       finish          complete the installation of libtool libraries
+       install         install libraries or executables
+       link            create a library or an executable
+       uninstall       remove libraries from an installed directory
+
+MODE-ARGS vary depending on the MODE.  When passed as first option,
+'--mode=MODE' may be abbreviated as 'MODE' or a unique abbreviation of that.
+Try '$progname --help --mode=MODE' for a more detailed description of MODE.
+
+When reporting a bug, please describe a test case to reproduce it and
+include the following information:
+
+       host-triplet:   $host
+       shell:          $SHELL
+       compiler:       $LTCC
+       compiler flags: $LTCFLAGS
+       linker:         $LD (gnu? $with_gnu_ld)
+       version:        $progname (GNU libtool) 2.4.7
+       automake:       `($AUTOMAKE --version) 2>/dev/null |$SED 1q`
+       autoconf:       `($AUTOCONF --version) 2>/dev/null |$SED 1q`
+
+Report bugs to <bug-libtool@gnu.org>.
+GNU libtool home page: <http://www.gnu.org/software/libtool/>.
+General help using GNU software: <http://www.gnu.org/gethelp/>."
+    exit 0
+}
+
+
+# func_lo2o OBJECT-NAME
+# ---------------------
+# Transform OBJECT-NAME from a '.lo' suffix to the platform specific
+# object suffix.
+
+lo2o=s/\\.lo\$/.$objext/
+o2lo=s/\\.$objext\$/.lo/
+
+if test yes = "$_G_HAVE_XSI_OPS"; then
+  eval 'func_lo2o ()
+  {
+    case $1 in
+      *.lo) func_lo2o_result=${1%.lo}.$objext ;;
+      *   ) func_lo2o_result=$1               ;;
+    esac
+  }'
+
+  # func_xform LIBOBJ-OR-SOURCE
+  # ---------------------------
+  # Transform LIBOBJ-OR-SOURCE from a '.o' or '.c' (or otherwise)
+  # suffix to a '.lo' libtool-object suffix.
+  eval 'func_xform ()
+  {
+    func_xform_result=${1%.*}.lo
+  }'
+else
+  # ...otherwise fall back to using sed.
+  func_lo2o ()
+  {
+    func_lo2o_result=`$ECHO "$1" | $SED "$lo2o"`
+  }
+
+  func_xform ()
+  {
+    func_xform_result=`$ECHO "$1" | $SED 's|\.[^.]*$|.lo|'`
+  }
+fi
+
+
+# func_fatal_configuration ARG...
+# -------------------------------
+# Echo program name prefixed message to standard error, followed by
+# a configuration failure hint, and exit.
+func_fatal_configuration ()
+{
+    func_fatal_error ${1+"$@"} \
+      "See the $PACKAGE documentation for more information." \
+      "Fatal configuration error."
+}
+
+
+# func_config
+# -----------
+# Display the configuration for all the tags in this script.
+func_config ()
+{
+    re_begincf='^# ### BEGIN LIBTOOL'
+    re_endcf='^# ### END LIBTOOL'
+
+    # Default configuration.
+    $SED "1,/$re_begincf CONFIG/d;/$re_endcf CONFIG/,\$d" < "$progpath"
+
+    # Now print the configurations for the tags.
+    for tagname in $taglist; do
+      $SED -n "/$re_begincf TAG CONFIG: $tagname\$/,/$re_endcf TAG CONFIG: $tagname\$/p" < "$progpath"
+    done
+
+    exit $?
+}
+
+
+# func_features
+# -------------
+# Display the features supported by this script.
+func_features ()
+{
+    echo "host: $host"
+    if test yes = "$build_libtool_libs"; then
+      echo "enable shared libraries"
+    else
+      echo "disable shared libraries"
+    fi
+    if test yes = "$build_old_libs"; then
+      echo "enable static libraries"
+    else
+      echo "disable static libraries"
+    fi
+
+    exit $?
+}
+
+
+# func_enable_tag TAGNAME
+# -----------------------
+# Verify that TAGNAME is valid, and either flag an error and exit, or
+# enable the TAGNAME tag.  We also add TAGNAME to the global $taglist
+# variable here.
+func_enable_tag ()
+{
+    # Global variable:
+    tagname=$1
+
+    re_begincf="^# ### BEGIN LIBTOOL TAG CONFIG: $tagname\$"
+    re_endcf="^# ### END LIBTOOL TAG CONFIG: $tagname\$"
+    sed_extractcf=/$re_begincf/,/$re_endcf/p
+
+    # Validate tagname.
+    case $tagname in
+      *[!-_A-Za-z0-9,/]*)
+        func_fatal_error "invalid tag name: $tagname"
+        ;;
+    esac
+
+    # Don't test for the "default" C tag, as we know it's
+    # there but not specially marked.
+    case $tagname in
+        CC) ;;
+    *)
+        if $GREP "$re_begincf" "$progpath" >/dev/null 2>&1; then
+	  taglist="$taglist $tagname"
+
+	  # Evaluate the configuration.  Be careful to quote the path
+	  # and the sed script, to avoid splitting on whitespace, but
+	  # also don't use non-portable quotes within backquotes within
+	  # quotes we have to do it in 2 steps:
+	  extractedcf=`$SED -n -e "$sed_extractcf" < "$progpath"`
+	  eval "$extractedcf"
+        else
+	  func_error "ignoring unknown tag $tagname"
+        fi
+        ;;
+    esac
+}
+
+
+# func_check_version_match
+# ------------------------
+# Ensure that we are using m4 macros, and libtool script from the same
+# release of libtool.
+func_check_version_match ()
+{
+    if test "$package_revision" != "$macro_revision"; then
+      if test "$VERSION" != "$macro_version"; then
+        if test -z "$macro_version"; then
+          cat >&2 <<_LT_EOF
+$progname: Version mismatch error.  This is $PACKAGE $VERSION, but the
+$progname: definition of this LT_INIT comes from an older release.
+$progname: You should recreate aclocal.m4 with macros from $PACKAGE $VERSION
+$progname: and run autoconf again.
+_LT_EOF
+        else
+          cat >&2 <<_LT_EOF
+$progname: Version mismatch error.  This is $PACKAGE $VERSION, but the
+$progname: definition of this LT_INIT comes from $PACKAGE $macro_version.
+$progname: You should recreate aclocal.m4 with macros from $PACKAGE $VERSION
+$progname: and run autoconf again.
+_LT_EOF
+        fi
+      else
+        cat >&2 <<_LT_EOF
+$progname: Version mismatch error.  This is $PACKAGE $VERSION, revision $package_revision,
+$progname: but the definition of this LT_INIT comes from revision $macro_revision.
+$progname: You should recreate aclocal.m4 with macros from revision $package_revision
+$progname: of $PACKAGE $VERSION and run autoconf again.
+_LT_EOF
+      fi
+
+      exit $EXIT_MISMATCH
+    fi
+}
+
+
+# libtool_options_prep [ARG]...
+# -----------------------------
+# Preparation for options parsed by libtool.
+libtool_options_prep ()
+{
+    $debug_mode
+
+    # Option defaults:
+    opt_config=false
+    opt_dlopen=
+    opt_dry_run=false
+    opt_help=false
+    opt_mode=
+    opt_preserve_dup_deps=false
+    opt_quiet=false
+
+    nonopt=
+    preserve_args=
+
+    _G_rc_lt_options_prep=:
+
+    # Shorthand for --mode=foo, only valid as the first argument
+    case $1 in
+    clean|clea|cle|cl)
+      shift; set dummy --mode clean ${1+"$@"}; shift
+      ;;
+    compile|compil|compi|comp|com|co|c)
+      shift; set dummy --mode compile ${1+"$@"}; shift
+      ;;
+    execute|execut|execu|exec|exe|ex|e)
+      shift; set dummy --mode execute ${1+"$@"}; shift
+      ;;
+    finish|finis|fini|fin|fi|f)
+      shift; set dummy --mode finish ${1+"$@"}; shift
+      ;;
+    install|instal|insta|inst|ins|in|i)
+      shift; set dummy --mode install ${1+"$@"}; shift
+      ;;
+    link|lin|li|l)
+      shift; set dummy --mode link ${1+"$@"}; shift
+      ;;
+    uninstall|uninstal|uninsta|uninst|unins|unin|uni|un|u)
+      shift; set dummy --mode uninstall ${1+"$@"}; shift
+      ;;
+    *)
+      _G_rc_lt_options_prep=false
+      ;;
+    esac
+
+    if $_G_rc_lt_options_prep; then
+      # Pass back the list of options.
+      func_quote eval ${1+"$@"}
+      libtool_options_prep_result=$func_quote_result
+    fi
+}
+func_add_hook func_options_prep libtool_options_prep
+
+
+# libtool_parse_options [ARG]...
+# ---------------------------------
+# Provide handling for libtool specific options.
+libtool_parse_options ()
+{
+    $debug_cmd
+
+    _G_rc_lt_parse_options=false
+
+    # Perform our own loop to consume as many options as possible in
+    # each iteration.
+    while test $# -gt 0; do
+      _G_match_lt_parse_options=:
+      _G_opt=$1
+      shift
+      case $_G_opt in
+        --dry-run|--dryrun|-n)
+                        opt_dry_run=:
+                        ;;
+
+        --config)       func_config ;;
+
+        --dlopen|-dlopen)
+                        opt_dlopen="${opt_dlopen+$opt_dlopen
+}$1"
+                        shift
+                        ;;
+
+        --preserve-dup-deps)
+                        opt_preserve_dup_deps=: ;;
+
+        --features)     func_features ;;
+
+        --finish)       set dummy --mode finish ${1+"$@"}; shift ;;
+
+        --help)         opt_help=: ;;
+
+        --help-all)     opt_help=': help-all' ;;
+
+        --mode)         test $# = 0 && func_missing_arg $_G_opt && break
+                        opt_mode=$1
+                        case $1 in
+                          # Valid mode arguments:
+                          clean|compile|execute|finish|install|link|relink|uninstall) ;;
+
+                          # Catch anything else as an error
+                          *) func_error "invalid argument for $_G_opt"
+                             exit_cmd=exit
+                             break
+                             ;;
+                        esac
+                        shift
+                        ;;
+
+        --no-silent|--no-quiet)
+                        opt_quiet=false
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+        --no-warnings|--no-warning|--no-warn)
+                        opt_warning=false
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+        --no-verbose)
+                        opt_verbose=false
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+        --silent|--quiet)
+                        opt_quiet=:
+                        opt_verbose=false
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+        --tag)          test $# = 0 && func_missing_arg $_G_opt && break
+                        opt_tag=$1
+                        func_append preserve_args " $_G_opt $1"
+                        func_enable_tag "$1"
+                        shift
+                        ;;
+
+        --verbose|-v)   opt_quiet=false
+                        opt_verbose=:
+                        func_append preserve_args " $_G_opt"
+                        ;;
+
+        # An option not handled by this hook function:
+        *)              set dummy "$_G_opt" ${1+"$@"} ; shift
+                        _G_match_lt_parse_options=false
+                        break
+                        ;;
+      esac
+      $_G_match_lt_parse_options && _G_rc_lt_parse_options=:
+    done
+
+    if $_G_rc_lt_parse_options; then
+      # save modified positional parameters for caller
+      func_quote eval ${1+"$@"}
+      libtool_parse_options_result=$func_quote_result
+    fi
+}
+func_add_hook func_parse_options libtool_parse_options
+
+
+
+# libtool_validate_options [ARG]...
+# ---------------------------------
+# Perform any sanity checks on option settings and/or unconsumed
+# arguments.
+libtool_validate_options ()
+{
+    # save first non-option argument
+    if test 0 -lt $#; then
+      nonopt=$1
+      shift
+    fi
+
+    # preserve --debug
+    test : = "$debug_cmd" || func_append preserve_args " --debug"
+
+    case $host in
+      # Solaris2 added to fix http://debbugs.gnu.org/cgi/bugreport.cgi?bug=16452
+      # see also: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59788
+      *cygwin* | *mingw* | *pw32* | *cegcc* | *solaris2* | *os2*)
+        # don't eliminate duplications in $postdeps and $predeps
+        opt_duplicate_compiler_generated_deps=:
+        ;;
+      *)
+        opt_duplicate_compiler_generated_deps=$opt_preserve_dup_deps
+        ;;
+    esac
+
+    $opt_help || {
+      # Sanity checks first:
+      func_check_version_match
+
+      test yes != "$build_libtool_libs" \
+        && test yes != "$build_old_libs" \
+        && func_fatal_configuration "not configured to build any kind of library"
+
+      # Darwin sucks
+      eval std_shrext=\"$shrext_cmds\"
+
+      # Only execute mode is allowed to have -dlopen flags.
+      if test -n "$opt_dlopen" && test execute != "$opt_mode"; then
+        func_error "unrecognized option '-dlopen'"
+        $ECHO "$help" 1>&2
+        exit $EXIT_FAILURE
+      fi
+
+      # Change the help message to a mode-specific one.
+      generic_help=$help
+      help="Try '$progname --help --mode=$opt_mode' for more information."
+    }
+
+    # Pass back the unparsed argument list
+    func_quote eval ${1+"$@"}
+    libtool_validate_options_result=$func_quote_result
+}
+func_add_hook func_validate_options libtool_validate_options
+
+
+# Process options as early as possible so that --help and --version
+# can return quickly.
+func_options ${1+"$@"}
+eval set dummy "$func_options_result"; shift
+
+
+
+## ----------- ##
+##    Main.    ##
+## ----------- ##
+
+magic='%%%MAGIC variable%%%'
+magic_exe='%%%MAGIC EXE variable%%%'
+
+# Global variables.
+extracted_archives=
+extracted_serial=0
+
+# If this variable is set in any of the actions, the command in it
+# will be execed at the end.  This prevents here-documents from being
+# left over by shells.
+exec_cmd=
+
+
+# A function that is used when there is no print builtin or printf.
+func_fallback_echo ()
+{
+  eval 'cat <<_LTECHO_EOF
+$1
+_LTECHO_EOF'
+}
+
+# func_generated_by_libtool
+# True iff stdin has been generated by Libtool. This function is only
+# a basic sanity check; it will hardly flush out determined imposters.
+func_generated_by_libtool_p ()
+{
+  $GREP "^# Generated by .*$PACKAGE" > /dev/null 2>&1
+}
+
+# func_lalib_p file
+# True iff FILE is a libtool '.la' library or '.lo' object file.
+# This function is only a basic sanity check; it will hardly flush out
+# determined imposters.
+func_lalib_p ()
+{
+    test -f "$1" &&
+      $SED -e 4q "$1" 2>/dev/null | func_generated_by_libtool_p
+}
+
+# func_lalib_unsafe_p file
+# True iff FILE is a libtool '.la' library or '.lo' object file.
+# This function implements the same check as func_lalib_p without
+# resorting to external programs.  To this end, it redirects stdin and
+# closes it afterwards, without saving the original file descriptor.
+# As a safety measure, use it only where a negative result would be
+# fatal anyway.  Works if 'file' does not exist.
+func_lalib_unsafe_p ()
+{
+    lalib_p=no
+    if test -f "$1" && test -r "$1" && exec 5<&0 <"$1"; then
+	for lalib_p_l in 1 2 3 4
+	do
+	    read lalib_p_line
+	    case $lalib_p_line in
+		\#\ Generated\ by\ *$PACKAGE* ) lalib_p=yes; break;;
+	    esac
+	done
+	exec 0<&5 5<&-
+    fi
+    test yes = "$lalib_p"
+}
+
+# func_ltwrapper_script_p file
+# True iff FILE is a libtool wrapper script
+# This function is only a basic sanity check; it will hardly flush out
+# determined imposters.
+func_ltwrapper_script_p ()
+{
+    test -f "$1" &&
+      $lt_truncate_bin < "$1" 2>/dev/null | func_generated_by_libtool_p
+}
+
+# func_ltwrapper_executable_p file
+# True iff FILE is a libtool wrapper executable
+# This function is only a basic sanity check; it will hardly flush out
+# determined imposters.
+func_ltwrapper_executable_p ()
+{
+    func_ltwrapper_exec_suffix=
+    case $1 in
+    *.exe) ;;
+    *) func_ltwrapper_exec_suffix=.exe ;;
+    esac
+    $GREP "$magic_exe" "$1$func_ltwrapper_exec_suffix" >/dev/null 2>&1
+}
+
+# func_ltwrapper_scriptname file
+# Assumes file is an ltwrapper_executable
+# uses $file to determine the appropriate filename for a
+# temporary ltwrapper_script.
+func_ltwrapper_scriptname ()
+{
+    func_dirname_and_basename "$1" "" "."
+    func_stripname '' '.exe' "$func_basename_result"
+    func_ltwrapper_scriptname_result=$func_dirname_result/$objdir/${func_stripname_result}_ltshwrapper
+}
+
+# func_ltwrapper_p file
+# True iff FILE is a libtool wrapper script or wrapper executable
+# This function is only a basic sanity check; it will hardly flush out
+# determined imposters.
+func_ltwrapper_p ()
+{
+    func_ltwrapper_script_p "$1" || func_ltwrapper_executable_p "$1"
+}
+
+
+# func_execute_cmds commands fail_cmd
+# Execute tilde-delimited COMMANDS.
+# If FAIL_CMD is given, eval that upon failure.
+# FAIL_CMD may read-access the current command in variable CMD!
+func_execute_cmds ()
+{
+    $debug_cmd
+
+    save_ifs=$IFS; IFS='~'
+    for cmd in $1; do
+      IFS=$sp$nl
+      eval cmd=\"$cmd\"
+      IFS=$save_ifs
+      func_show_eval "$cmd" "${2-:}"
+    done
+    IFS=$save_ifs
+}
+
+
+# func_source file
+# Source FILE, adding directory component if necessary.
+# Note that it is not necessary on cygwin/mingw to append a dot to
+# FILE even if both FILE and FILE.exe exist: automatic-append-.exe
+# behavior happens only for exec(3), not for open(2)!  Also, sourcing
+# 'FILE.' does not work on cygwin managed mounts.
+func_source ()
+{
+    $debug_cmd
+
+    case $1 in
+    */* | *\\*)	. "$1" ;;
+    *)		. "./$1" ;;
+    esac
+}
+
+
+# func_resolve_sysroot PATH
+# Replace a leading = in PATH with a sysroot.  Store the result into
+# func_resolve_sysroot_result
+func_resolve_sysroot ()
+{
+  func_resolve_sysroot_result=$1
+  case $func_resolve_sysroot_result in
+  =*)
+    func_stripname '=' '' "$func_resolve_sysroot_result"
+    func_resolve_sysroot_result=$lt_sysroot$func_stripname_result
+    ;;
+  esac
+}
+
+# func_replace_sysroot PATH
+# If PATH begins with the sysroot, replace it with = and
+# store the result into func_replace_sysroot_result.
+func_replace_sysroot ()
+{
+  case $lt_sysroot:$1 in
+  ?*:"$lt_sysroot"*)
+    func_stripname "$lt_sysroot" '' "$1"
+    func_replace_sysroot_result='='$func_stripname_result
+    ;;
+  *)
+    # Including no sysroot.
+    func_replace_sysroot_result=$1
+    ;;
+  esac
+}
+
+# func_infer_tag arg
+# Infer tagged configuration to use if any are available and
+# if one wasn't chosen via the "--tag" command line option.
+# Only attempt this if the compiler in the base compile
+# command doesn't match the default compiler.
+# arg is usually of the form 'gcc ...'
+func_infer_tag ()
+{
+    $debug_cmd
+
+    if test -n "$available_tags" && test -z "$tagname"; then
+      CC_quoted=
+      for arg in $CC; do
+	func_append_quoted CC_quoted "$arg"
+      done
+      CC_expanded=`func_echo_all $CC`
+      CC_quoted_expanded=`func_echo_all $CC_quoted`
+      case $@ in
+      # Blanks in the command may have been stripped by the calling shell,
+      # but not from the CC environment variable when configure was run.
+      " $CC "* | "$CC "* | " $CC_expanded "* | "$CC_expanded "* | \
+      " $CC_quoted"* | "$CC_quoted "* | " $CC_quoted_expanded "* | "$CC_quoted_expanded "*) ;;
+      # Blanks at the start of $base_compile will cause this to fail
+      # if we don't check for them as well.
+      *)
+	for z in $available_tags; do
+	  if $GREP "^# ### BEGIN LIBTOOL TAG CONFIG: $z$" < "$progpath" > /dev/null; then
+	    # Evaluate the configuration.
+	    eval "`$SED -n -e '/^# ### BEGIN LIBTOOL TAG CONFIG: '$z'$/,/^# ### END LIBTOOL TAG CONFIG: '$z'$/p' < $progpath`"
+	    CC_quoted=
+	    for arg in $CC; do
+	      # Double-quote args containing other shell metacharacters.
+	      func_append_quoted CC_quoted "$arg"
+	    done
+	    CC_expanded=`func_echo_all $CC`
+	    CC_quoted_expanded=`func_echo_all $CC_quoted`
+	    case "$@ " in
+	    " $CC "* | "$CC "* | " $CC_expanded "* | "$CC_expanded "* | \
+	    " $CC_quoted"* | "$CC_quoted "* | " $CC_quoted_expanded "* | "$CC_quoted_expanded "*)
+	      # The compiler in the base compile command matches
+	      # the one in the tagged configuration.
+	      # Assume this is the tagged configuration we want.
+	      tagname=$z
+	      break
+	      ;;
+	    esac
+	  fi
+	done
+	# If $tagname still isn't set, then no tagged configuration
+	# was found and let the user know that the "--tag" command
+	# line option must be used.
+	if test -z "$tagname"; then
+	  func_echo "unable to infer tagged configuration"
+	  func_fatal_error "specify a tag with '--tag'"
+#	else
+#	  func_verbose "using $tagname tagged configuration"
+	fi
+	;;
+      esac
+    fi
+}
+
+
+
+# func_write_libtool_object output_name pic_name nonpic_name
+# Create a libtool object file (analogous to a ".la" file),
+# but don't create it if we're doing a dry run.
+func_write_libtool_object ()
+{
+    write_libobj=$1
+    if test yes = "$build_libtool_libs"; then
+      write_lobj=\'$2\'
+    else
+      write_lobj=none
+    fi
+
+    if test yes = "$build_old_libs"; then
+      write_oldobj=\'$3\'
+    else
+      write_oldobj=none
+    fi
+
+    $opt_dry_run || {
+      cat >${write_libobj}T <<EOF
+# $write_libobj - a libtool object file
+# Generated by $PROGRAM (GNU $PACKAGE) $VERSION
+#
+# Please DO NOT delete this file!
+# It is necessary for linking the library.
+
+# Name of the PIC object.
+pic_object=$write_lobj
+
+# Name of the non-PIC object
+non_pic_object=$write_oldobj
+
+EOF
+      $MV "${write_libobj}T" "$write_libobj"
+    }
+}
+
+
+##################################################
+# FILE NAME AND PATH CONVERSION HELPER FUNCTIONS #
+##################################################
+
+# func_convert_core_file_wine_to_w32 ARG
+# Helper function used by file name conversion functions when $build is *nix,
+# and $host is mingw, cygwin, or some other w32 environment. Relies on a
+# correctly configured wine environment available, with the winepath program
+# in $build's $PATH.
+#
+# ARG is the $build file name to be converted to w32 format.
+# Result is available in $func_convert_core_file_wine_to_w32_result, and will
+# be empty on error (or when ARG is empty)
+func_convert_core_file_wine_to_w32 ()
+{
+  $debug_cmd
+
+  func_convert_core_file_wine_to_w32_result=$1
+  if test -n "$1"; then
+    # Unfortunately, winepath does not exit with a non-zero error code, so we
+    # are forced to check the contents of stdout. On the other hand, if the
+    # command is not found, the shell will set an exit code of 127 and print
+    # *an error message* to stdout. So we must check for both error code of
+    # zero AND non-empty stdout, which explains the odd construction:
+    func_convert_core_file_wine_to_w32_tmp=`winepath -w "$1" 2>/dev/null`
+    if test "$?" -eq 0 && test -n "$func_convert_core_file_wine_to_w32_tmp"; then
+      func_convert_core_file_wine_to_w32_result=`$ECHO "$func_convert_core_file_wine_to_w32_tmp" |
+        $SED -e "$sed_naive_backslashify"`
+    else
+      func_convert_core_file_wine_to_w32_result=
+    fi
+  fi
+}
+# end: func_convert_core_file_wine_to_w32
+
+
+# func_convert_core_path_wine_to_w32 ARG
+# Helper function used by path conversion functions when $build is *nix, and
+# $host is mingw, cygwin, or some other w32 environment. Relies on a correctly
+# configured wine environment available, with the winepath program in $build's
+# $PATH. Assumes ARG has no leading or trailing path separator characters.
+#
+# ARG is path to be converted from $build format to win32.
+# Result is available in $func_convert_core_path_wine_to_w32_result.
+# Unconvertible file (directory) names in ARG are skipped; if no directory names
+# are convertible, then the result may be empty.
+func_convert_core_path_wine_to_w32 ()
+{
+  $debug_cmd
+
+  # unfortunately, winepath doesn't convert paths, only file names
+  func_convert_core_path_wine_to_w32_result=
+  if test -n "$1"; then
+    oldIFS=$IFS
+    IFS=:
+    for func_convert_core_path_wine_to_w32_f in $1; do
+      IFS=$oldIFS
+      func_convert_core_file_wine_to_w32 "$func_convert_core_path_wine_to_w32_f"
+      if test -n "$func_convert_core_file_wine_to_w32_result"; then
+        if test -z "$func_convert_core_path_wine_to_w32_result"; then
+          func_convert_core_path_wine_to_w32_result=$func_convert_core_file_wine_to_w32_result
+        else
+          func_append func_convert_core_path_wine_to_w32_result ";$func_convert_core_file_wine_to_w32_result"
+        fi
+      fi
+    done
+    IFS=$oldIFS
+  fi
+}
+# end: func_convert_core_path_wine_to_w32
+
+
+# func_cygpath ARGS...
+# Wrapper around calling the cygpath program via LT_CYGPATH. This is used when
+# when (1) $build is *nix and Cygwin is hosted via a wine environment; or (2)
+# $build is MSYS and $host is Cygwin, or (3) $build is Cygwin. In case (1) or
+# (2), returns the Cygwin file name or path in func_cygpath_result (input
+# file name or path is assumed to be in w32 format, as previously converted
+# from $build's *nix or MSYS format). In case (3), returns the w32 file name
+# or path in func_cygpath_result (input file name or path is assumed to be in
+# Cygwin format). Returns an empty string on error.
+#
+# ARGS are passed to cygpath, with the last one being the file name or path to
+# be converted.
+#
+# Specify the absolute *nix (or w32) name to cygpath in the LT_CYGPATH
+# environment variable; do not put it in $PATH.
+func_cygpath ()
+{
+  $debug_cmd
+
+  if test -n "$LT_CYGPATH" && test -f "$LT_CYGPATH"; then
+    func_cygpath_result=`$LT_CYGPATH "$@" 2>/dev/null`
+    if test "$?" -ne 0; then
+      # on failure, ensure result is empty
+      func_cygpath_result=
+    fi
+  else
+    func_cygpath_result=
+    func_error "LT_CYGPATH is empty or specifies non-existent file: '$LT_CYGPATH'"
+  fi
+}
+#end: func_cygpath
+
+
+# func_convert_core_msys_to_w32 ARG
+# Convert file name or path ARG from MSYS format to w32 format.  Return
+# result in func_convert_core_msys_to_w32_result.
+func_convert_core_msys_to_w32 ()
+{
+  $debug_cmd
+
+  # awkward: cmd appends spaces to result
+  func_convert_core_msys_to_w32_result=`( cmd //c echo "$1" ) 2>/dev/null |
+    $SED -e 's/[ ]*$//' -e "$sed_naive_backslashify"`
+}
+#end: func_convert_core_msys_to_w32
+
+
+# func_convert_file_check ARG1 ARG2
+# Verify that ARG1 (a file name in $build format) was converted to $host
+# format in ARG2. Otherwise, emit an error message, but continue (resetting
+# func_to_host_file_result to ARG1).
+func_convert_file_check ()
+{
+  $debug_cmd
+
+  if test -z "$2" && test -n "$1"; then
+    func_error "Could not determine host file name corresponding to"
+    func_error "  '$1'"
+    func_error "Continuing, but uninstalled executables may not work."
+    # Fallback:
+    func_to_host_file_result=$1
+  fi
+}
+# end func_convert_file_check
+
+
+# func_convert_path_check FROM_PATHSEP TO_PATHSEP FROM_PATH TO_PATH
+# Verify that FROM_PATH (a path in $build format) was converted to $host
+# format in TO_PATH. Otherwise, emit an error message, but continue, resetting
+# func_to_host_file_result to a simplistic fallback value (see below).
+func_convert_path_check ()
+{
+  $debug_cmd
+
+  if test -z "$4" && test -n "$3"; then
+    func_error "Could not determine the host path corresponding to"
+    func_error "  '$3'"
+    func_error "Continuing, but uninstalled executables may not work."
+    # Fallback.  This is a deliberately simplistic "conversion" and
+    # should not be "improved".  See libtool.info.
+    if test "x$1" != "x$2"; then
+      lt_replace_pathsep_chars="s|$1|$2|g"
+      func_to_host_path_result=`echo "$3" |
+        $SED -e "$lt_replace_pathsep_chars"`
+    else
+      func_to_host_path_result=$3
+    fi
+  fi
+}
+# end func_convert_path_check
+
+
+# func_convert_path_front_back_pathsep FRONTPAT BACKPAT REPL ORIG
+# Modifies func_to_host_path_result by prepending REPL if ORIG matches FRONTPAT
+# and appending REPL if ORIG matches BACKPAT.
+func_convert_path_front_back_pathsep ()
+{
+  $debug_cmd
+
+  case $4 in
+  $1 ) func_to_host_path_result=$3$func_to_host_path_result
+    ;;
+  esac
+  case $4 in
+  $2 ) func_append func_to_host_path_result "$3"
+    ;;
+  esac
+}
+# end func_convert_path_front_back_pathsep
+
+
+##################################################
+# $build to $host FILE NAME CONVERSION FUNCTIONS #
+##################################################
+# invoked via '$to_host_file_cmd ARG'
+#
+# In each case, ARG is the path to be converted from $build to $host format.
+# Result will be available in $func_to_host_file_result.
+
+
+# func_to_host_file ARG
+# Converts the file name ARG from $build format to $host format. Return result
+# in func_to_host_file_result.
+func_to_host_file ()
+{
+  $debug_cmd
+
+  $to_host_file_cmd "$1"
+}
+# end func_to_host_file
+
+
+# func_to_tool_file ARG LAZY
+# converts the file name ARG from $build format to toolchain format. Return
+# result in func_to_tool_file_result.  If the conversion in use is listed
+# in (the comma separated) LAZY, no conversion takes place.
+func_to_tool_file ()
+{
+  $debug_cmd
+
+  case ,$2, in
+    *,"$to_tool_file_cmd",*)
+      func_to_tool_file_result=$1
+      ;;
+    *)
+      $to_tool_file_cmd "$1"
+      func_to_tool_file_result=$func_to_host_file_result
+      ;;
+  esac
+}
+# end func_to_tool_file
+
+
+# func_convert_file_noop ARG
+# Copy ARG to func_to_host_file_result.
+func_convert_file_noop ()
+{
+  func_to_host_file_result=$1
+}
+# end func_convert_file_noop
+
+
+# func_convert_file_msys_to_w32 ARG
+# Convert file name ARG from (mingw) MSYS to (mingw) w32 format; automatic
+# conversion to w32 is not available inside the cwrapper.  Returns result in
+# func_to_host_file_result.
+func_convert_file_msys_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    func_convert_core_msys_to_w32 "$1"
+    func_to_host_file_result=$func_convert_core_msys_to_w32_result
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_msys_to_w32
+
+
+# func_convert_file_cygwin_to_w32 ARG
+# Convert file name ARG from Cygwin to w32 format.  Returns result in
+# func_to_host_file_result.
+func_convert_file_cygwin_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    # because $build is cygwin, we call "the" cygpath in $PATH; no need to use
+    # LT_CYGPATH in this case.
+    func_to_host_file_result=`cygpath -m "$1"`
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_cygwin_to_w32
+
+
+# func_convert_file_nix_to_w32 ARG
+# Convert file name ARG from *nix to w32 format.  Requires a wine environment
+# and a working winepath. Returns result in func_to_host_file_result.
+func_convert_file_nix_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    func_convert_core_file_wine_to_w32 "$1"
+    func_to_host_file_result=$func_convert_core_file_wine_to_w32_result
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_nix_to_w32
+
+
+# func_convert_file_msys_to_cygwin ARG
+# Convert file name ARG from MSYS to Cygwin format.  Requires LT_CYGPATH set.
+# Returns result in func_to_host_file_result.
+func_convert_file_msys_to_cygwin ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    func_convert_core_msys_to_w32 "$1"
+    func_cygpath -u "$func_convert_core_msys_to_w32_result"
+    func_to_host_file_result=$func_cygpath_result
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_msys_to_cygwin
+
+
+# func_convert_file_nix_to_cygwin ARG
+# Convert file name ARG from *nix to Cygwin format.  Requires Cygwin installed
+# in a wine environment, working winepath, and LT_CYGPATH set.  Returns result
+# in func_to_host_file_result.
+func_convert_file_nix_to_cygwin ()
+{
+  $debug_cmd
+
+  func_to_host_file_result=$1
+  if test -n "$1"; then
+    # convert from *nix to w32, then use cygpath to convert from w32 to cygwin.
+    func_convert_core_file_wine_to_w32 "$1"
+    func_cygpath -u "$func_convert_core_file_wine_to_w32_result"
+    func_to_host_file_result=$func_cygpath_result
+  fi
+  func_convert_file_check "$1" "$func_to_host_file_result"
+}
+# end func_convert_file_nix_to_cygwin
+
+
+#############################################
+# $build to $host PATH CONVERSION FUNCTIONS #
+#############################################
+# invoked via '$to_host_path_cmd ARG'
+#
+# In each case, ARG is the path to be converted from $build to $host format.
+# The result will be available in $func_to_host_path_result.
+#
+# Path separators are also converted from $build format to $host format.  If
+# ARG begins or ends with a path separator character, it is preserved (but
+# converted to $host format) on output.
+#
+# All path conversion functions are named using the following convention:
+#   file name conversion function    : func_convert_file_X_to_Y ()
+#   path conversion function         : func_convert_path_X_to_Y ()
+# where, for any given $build/$host combination the 'X_to_Y' value is the
+# same.  If conversion functions are added for new $build/$host combinations,
+# the two new functions must follow this pattern, or func_init_to_host_path_cmd
+# will break.
+
+
+# func_init_to_host_path_cmd
+# Ensures that function "pointer" variable $to_host_path_cmd is set to the
+# appropriate value, based on the value of $to_host_file_cmd.
+to_host_path_cmd=
+func_init_to_host_path_cmd ()
+{
+  $debug_cmd
+
+  if test -z "$to_host_path_cmd"; then
+    func_stripname 'func_convert_file_' '' "$to_host_file_cmd"
+    to_host_path_cmd=func_convert_path_$func_stripname_result
+  fi
+}
+
+
+# func_to_host_path ARG
+# Converts the path ARG from $build format to $host format. Return result
+# in func_to_host_path_result.
+func_to_host_path ()
+{
+  $debug_cmd
+
+  func_init_to_host_path_cmd
+  $to_host_path_cmd "$1"
+}
+# end func_to_host_path
+
+
+# func_convert_path_noop ARG
+# Copy ARG to func_to_host_path_result.
+func_convert_path_noop ()
+{
+  func_to_host_path_result=$1
+}
+# end func_convert_path_noop
+
+
+# func_convert_path_msys_to_w32 ARG
+# Convert path ARG from (mingw) MSYS to (mingw) w32 format; automatic
+# conversion to w32 is not available inside the cwrapper.  Returns result in
+# func_to_host_path_result.
+func_convert_path_msys_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # Remove leading and trailing path separator characters from ARG.  MSYS
+    # behavior is inconsistent here; cygpath turns them into '.;' and ';.';
+    # and winepath ignores them completely.
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_convert_core_msys_to_w32 "$func_to_host_path_tmp1"
+    func_to_host_path_result=$func_convert_core_msys_to_w32_result
+    func_convert_path_check : ";" \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" ";" "$1"
+  fi
+}
+# end func_convert_path_msys_to_w32
+
+
+# func_convert_path_cygwin_to_w32 ARG
+# Convert path ARG from Cygwin to w32 format.  Returns result in
+# func_to_host_file_result.
+func_convert_path_cygwin_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # See func_convert_path_msys_to_w32:
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_to_host_path_result=`cygpath -m -p "$func_to_host_path_tmp1"`
+    func_convert_path_check : ";" \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" ";" "$1"
+  fi
+}
+# end func_convert_path_cygwin_to_w32
+
+
+# func_convert_path_nix_to_w32 ARG
+# Convert path ARG from *nix to w32 format.  Requires a wine environment and
+# a working winepath.  Returns result in func_to_host_file_result.
+func_convert_path_nix_to_w32 ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # See func_convert_path_msys_to_w32:
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_convert_core_path_wine_to_w32 "$func_to_host_path_tmp1"
+    func_to_host_path_result=$func_convert_core_path_wine_to_w32_result
+    func_convert_path_check : ";" \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" ";" "$1"
+  fi
+}
+# end func_convert_path_nix_to_w32
+
+
+# func_convert_path_msys_to_cygwin ARG
+# Convert path ARG from MSYS to Cygwin format.  Requires LT_CYGPATH set.
+# Returns result in func_to_host_file_result.
+func_convert_path_msys_to_cygwin ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # See func_convert_path_msys_to_w32:
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_convert_core_msys_to_w32 "$func_to_host_path_tmp1"
+    func_cygpath -u -p "$func_convert_core_msys_to_w32_result"
+    func_to_host_path_result=$func_cygpath_result
+    func_convert_path_check : : \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" : "$1"
+  fi
+}
+# end func_convert_path_msys_to_cygwin
+
+
+# func_convert_path_nix_to_cygwin ARG
+# Convert path ARG from *nix to Cygwin format.  Requires Cygwin installed in a
+# a wine environment, working winepath, and LT_CYGPATH set.  Returns result in
+# func_to_host_file_result.
+func_convert_path_nix_to_cygwin ()
+{
+  $debug_cmd
+
+  func_to_host_path_result=$1
+  if test -n "$1"; then
+    # Remove leading and trailing path separator characters from
+    # ARG. msys behavior is inconsistent here, cygpath turns them
+    # into '.;' and ';.', and winepath ignores them completely.
+    func_stripname : : "$1"
+    func_to_host_path_tmp1=$func_stripname_result
+    func_convert_core_path_wine_to_w32 "$func_to_host_path_tmp1"
+    func_cygpath -u -p "$func_convert_core_path_wine_to_w32_result"
+    func_to_host_path_result=$func_cygpath_result
+    func_convert_path_check : : \
+      "$func_to_host_path_tmp1" "$func_to_host_path_result"
+    func_convert_path_front_back_pathsep ":*" "*:" : "$1"
+  fi
+}
+# end func_convert_path_nix_to_cygwin
+
+
+# func_dll_def_p FILE
+# True iff FILE is a Windows DLL '.def' file.
+# Keep in sync with _LT_DLL_DEF_P in libtool.m4
+func_dll_def_p ()
+{
+  $debug_cmd
+
+  func_dll_def_p_tmp=`$SED -n \
+    -e 's/^[	 ]*//' \
+    -e '/^\(;.*\)*$/d' \
+    -e 's/^\(EXPORTS\|LIBRARY\)\([	 ].*\)*$/DEF/p' \
+    -e q \
+    "$1"`
+  test DEF = "$func_dll_def_p_tmp"
+}
+
+
+# func_mode_compile arg...
+func_mode_compile ()
+{
+    $debug_cmd
+
+    # Get the compilation command and the source file.
+    base_compile=
+    srcfile=$nonopt  #  always keep a non-empty value in "srcfile"
+    suppress_opt=yes
+    suppress_output=
+    arg_mode=normal
+    libobj=
+    later=
+    pie_flag=
+
+    for arg
+    do
+      case $arg_mode in
+      arg  )
+	# do not "continue".  Instead, add this to base_compile
+	lastarg=$arg
+	arg_mode=normal
+	;;
+
+      target )
+	libobj=$arg
+	arg_mode=normal
+	continue
+	;;
+
+      normal )
+	# Accept any command-line options.
+	case $arg in
+	-o)
+	  test -n "$libobj" && \
+	    func_fatal_error "you cannot specify '-o' more than once"
+	  arg_mode=target
+	  continue
+	  ;;
+
+	-pie | -fpie | -fPIE)
+          func_append pie_flag " $arg"
+	  continue
+	  ;;
+
+	-shared | -static | -prefer-pic | -prefer-non-pic)
+	  func_append later " $arg"
+	  continue
+	  ;;
+
+	-no-suppress)
+	  suppress_opt=no
+	  continue
+	  ;;
+
+	-Xcompiler)
+	  arg_mode=arg  #  the next one goes into the "base_compile" arg list
+	  continue      #  The current "srcfile" will either be retained or
+	  ;;            #  replaced later.  I would guess that would be a bug.
+
+	-Wc,*)
+	  func_stripname '-Wc,' '' "$arg"
+	  args=$func_stripname_result
+	  lastarg=
+	  save_ifs=$IFS; IFS=,
+	  for arg in $args; do
+	    IFS=$save_ifs
+	    func_append_quoted lastarg "$arg"
+	  done
+	  IFS=$save_ifs
+	  func_stripname ' ' '' "$lastarg"
+	  lastarg=$func_stripname_result
+
+	  # Add the arguments to base_compile.
+	  func_append base_compile " $lastarg"
+	  continue
+	  ;;
+
+	*)
+	  # Accept the current argument as the source file.
+	  # The previous "srcfile" becomes the current argument.
+	  #
+	  lastarg=$srcfile
+	  srcfile=$arg
+	  ;;
+	esac  #  case $arg
+	;;
+      esac    #  case $arg_mode
+
+      # Aesthetically quote the previous argument.
+      func_append_quoted base_compile "$lastarg"
+    done # for arg
+
+    case $arg_mode in
+    arg)
+      func_fatal_error "you must specify an argument for -Xcompile"
+      ;;
+    target)
+      func_fatal_error "you must specify a target with '-o'"
+      ;;
+    *)
+      # Get the name of the library object.
+      test -z "$libobj" && {
+	func_basename "$srcfile"
+	libobj=$func_basename_result
+      }
+      ;;
+    esac
+
+    # Recognize several different file suffixes.
+    # If the user specifies -o file.o, it is replaced with file.lo
+    case $libobj in
+    *.[cCFSifmso] | \
+    *.ada | *.adb | *.ads | *.asm | \
+    *.c++ | *.cc | *.ii | *.class | *.cpp | *.cxx | \
+    *.[fF][09]? | *.for | *.java | *.go | *.obj | *.sx | *.cu | *.cup)
+      func_xform "$libobj"
+      libobj=$func_xform_result
+      ;;
+    esac
+
+    case $libobj in
+    *.lo) func_lo2o "$libobj"; obj=$func_lo2o_result ;;
+    *)
+      func_fatal_error "cannot determine name of library object from '$libobj'"
+      ;;
+    esac
+
+    func_infer_tag $base_compile
+
+    for arg in $later; do
+      case $arg in
+      -shared)
+	test yes = "$build_libtool_libs" \
+	  || func_fatal_configuration "cannot build a shared library"
+	build_old_libs=no
+	continue
+	;;
+
+      -static)
+	build_libtool_libs=no
+	build_old_libs=yes
+	continue
+	;;
+
+      -prefer-pic)
+	pic_mode=yes
+	continue
+	;;
+
+      -prefer-non-pic)
+	pic_mode=no
+	continue
+	;;
+      esac
+    done
+
+    func_quote_arg pretty "$libobj"
+    test "X$libobj" != "X$func_quote_arg_result" \
+      && $ECHO "X$libobj" | $GREP '[]~#^*{};<>?"'"'"'	 &()|`$[]' \
+      && func_warning "libobj name '$libobj' may not contain shell special characters."
+    func_dirname_and_basename "$obj" "/" ""
+    objname=$func_basename_result
+    xdir=$func_dirname_result
+    lobj=$xdir$objdir/$objname
+
+    test -z "$base_compile" && \
+      func_fatal_help "you must specify a compilation command"
+
+    # Delete any leftover library objects.
+    if test yes = "$build_old_libs"; then
+      removelist="$obj $lobj $libobj ${libobj}T"
+    else
+      removelist="$lobj $libobj ${libobj}T"
+    fi
+
+    # On Cygwin there's no "real" PIC flag so we must build both object types
+    case $host_os in
+    cygwin* | mingw* | pw32* | os2* | cegcc*)
+      pic_mode=default
+      ;;
+    esac
+    if test no = "$pic_mode" && test pass_all != "$deplibs_check_method"; then
+      # non-PIC code in shared libraries is not supported
+      pic_mode=default
+    fi
+
+    # Calculate the filename of the output object if compiler does
+    # not support -o with -c
+    if test no = "$compiler_c_o"; then
+      output_obj=`$ECHO "$srcfile" | $SED 's%^.*/%%; s%\.[^.]*$%%'`.$objext
+      lockfile=$output_obj.lock
+    else
+      output_obj=
+      need_locks=no
+      lockfile=
+    fi
+
+    # Lock this critical section if it is needed
+    # We use this script file to make the link, it avoids creating a new file
+    if test yes = "$need_locks"; then
+      until $opt_dry_run || ln "$progpath" "$lockfile" 2>/dev/null; do
+	func_echo "Waiting for $lockfile to be removed"
+	sleep 2
+      done
+    elif test warn = "$need_locks"; then
+      if test -f "$lockfile"; then
+	$ECHO "\
+*** ERROR, $lockfile exists and contains:
+`cat $lockfile 2>/dev/null`
+
+This indicates that another process is trying to use the same
+temporary object file, and libtool could not work around it because
+your compiler does not support '-c' and '-o' together.  If you
+repeat this compilation, it may succeed, by chance, but you had better
+avoid parallel builds (make -j) in this platform, or get a better
+compiler."
+
+	$opt_dry_run || $RM $removelist
+	exit $EXIT_FAILURE
+      fi
+      func_append removelist " $output_obj"
+      $ECHO "$srcfile" > "$lockfile"
+    fi
+
+    $opt_dry_run || $RM $removelist
+    func_append removelist " $lockfile"
+    trap '$opt_dry_run || $RM $removelist; exit $EXIT_FAILURE' 1 2 15
+
+    func_to_tool_file "$srcfile" func_convert_file_msys_to_w32
+    srcfile=$func_to_tool_file_result
+    func_quote_arg pretty "$srcfile"
+    qsrcfile=$func_quote_arg_result
+
+    # Only build a PIC object if we are building libtool libraries.
+    if test yes = "$build_libtool_libs"; then
+      # Without this assignment, base_compile gets emptied.
+      fbsd_hideous_sh_bug=$base_compile
+
+      if test no != "$pic_mode"; then
+	command="$base_compile $qsrcfile $pic_flag"
+      else
+	# Don't build PIC code
+	command="$base_compile $qsrcfile"
+      fi
+
+      func_mkdir_p "$xdir$objdir"
+
+      if test -z "$output_obj"; then
+	# Place PIC objects in $objdir
+	func_append command " -o $lobj"
+      fi
+
+      func_show_eval_locale "$command"	\
+          'test -n "$output_obj" && $RM $removelist; exit $EXIT_FAILURE'
+
+      if test warn = "$need_locks" &&
+	 test "X`cat $lockfile 2>/dev/null`" != "X$srcfile"; then
+	$ECHO "\
+*** ERROR, $lockfile contains:
+`cat $lockfile 2>/dev/null`
+
+but it should contain:
+$srcfile
+
+This indicates that another process is trying to use the same
+temporary object file, and libtool could not work around it because
+your compiler does not support '-c' and '-o' together.  If you
+repeat this compilation, it may succeed, by chance, but you had better
+avoid parallel builds (make -j) in this platform, or get a better
+compiler."
+
+	$opt_dry_run || $RM $removelist
+	exit $EXIT_FAILURE
+      fi
+
+      # Just move the object if needed, then go on to compile the next one
+      if test -n "$output_obj" && test "X$output_obj" != "X$lobj"; then
+	func_show_eval '$MV "$output_obj" "$lobj"' \
+	  'error=$?; $opt_dry_run || $RM $removelist; exit $error'
+      fi
+
+      # Allow error messages only from the first compilation.
+      if test yes = "$suppress_opt"; then
+	suppress_output=' >/dev/null 2>&1'
+      fi
+    fi
+
+    # Only build a position-dependent object if we build old libraries.
+    if test yes = "$build_old_libs"; then
+      if test yes != "$pic_mode"; then
+	# Don't build PIC code
+	command="$base_compile $qsrcfile$pie_flag"
+      else
+	command="$base_compile $qsrcfile $pic_flag"
+      fi
+      if test yes = "$compiler_c_o"; then
+	func_append command " -o $obj"
+      fi
+
+      # Suppress compiler output if we already did a PIC compilation.
+      func_append command "$suppress_output"
+      func_show_eval_locale "$command" \
+        '$opt_dry_run || $RM $removelist; exit $EXIT_FAILURE'
+
+      if test warn = "$need_locks" &&
+	 test "X`cat $lockfile 2>/dev/null`" != "X$srcfile"; then
+	$ECHO "\
+*** ERROR, $lockfile contains:
+`cat $lockfile 2>/dev/null`
+
+but it should contain:
+$srcfile
+
+This indicates that another process is trying to use the same
+temporary object file, and libtool could not work around it because
+your compiler does not support '-c' and '-o' together.  If you
+repeat this compilation, it may succeed, by chance, but you had better
+avoid parallel builds (make -j) in this platform, or get a better
+compiler."
+
+	$opt_dry_run || $RM $removelist
+	exit $EXIT_FAILURE
+      fi
+
+      # Just move the object if needed
+      if test -n "$output_obj" && test "X$output_obj" != "X$obj"; then
+	func_show_eval '$MV "$output_obj" "$obj"' \
+	  'error=$?; $opt_dry_run || $RM $removelist; exit $error'
+      fi
+    fi
+
+    $opt_dry_run || {
+      func_write_libtool_object "$libobj" "$objdir/$objname" "$objname"
+
+      # Unlock the critical section if it was locked
+      if test no != "$need_locks"; then
+	removelist=$lockfile
+        $RM "$lockfile"
+      fi
+    }
+
+    exit $EXIT_SUCCESS
+}
+
+$opt_help || {
+  test compile = "$opt_mode" && func_mode_compile ${1+"$@"}
+}
+
+func_mode_help ()
+{
+    # We need to display help for each of the modes.
+    case $opt_mode in
+      "")
+        # Generic help is extracted from the usage comments
+        # at the start of this file.
+        func_help
+        ;;
+
+      clean)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=clean RM [RM-OPTION]... FILE...
+
+Remove files from the build directory.
+
+RM is the name of the program to use to delete files associated with each FILE
+(typically '/bin/rm').  RM-OPTIONS are options (such as '-f') to be passed
+to RM.
+
+If FILE is a libtool library, object or program, all the files associated
+with it are deleted. Otherwise, only FILE itself is deleted using RM."
+        ;;
+
+      compile)
+      $ECHO \
+"Usage: $progname [OPTION]... --mode=compile COMPILE-COMMAND... SOURCEFILE
+
+Compile a source file into a libtool library object.
+
+This mode accepts the following additional options:
+
+  -o OUTPUT-FILE    set the output file name to OUTPUT-FILE
+  -no-suppress      do not suppress compiler output for multiple passes
+  -prefer-pic       try to build PIC objects only
+  -prefer-non-pic   try to build non-PIC objects only
+  -shared           do not build a '.o' file suitable for static linking
+  -static           only build a '.o' file suitable for static linking
+  -Wc,FLAG
+  -Xcompiler FLAG   pass FLAG directly to the compiler
+
+COMPILE-COMMAND is a command to be used in creating a 'standard' object file
+from the given SOURCEFILE.
+
+The output file name is determined by removing the directory component from
+SOURCEFILE, then substituting the C source code suffix '.c' with the
+library object suffix, '.lo'."
+        ;;
+
+      execute)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=execute COMMAND [ARGS]...
+
+Automatically set library path, then run a program.
+
+This mode accepts the following additional options:
+
+  -dlopen FILE      add the directory containing FILE to the library path
+
+This mode sets the library path environment variable according to '-dlopen'
+flags.
+
+If any of the ARGS are libtool executable wrappers, then they are translated
+into their corresponding uninstalled binary, and any of their required library
+directories are added to the library path.
+
+Then, COMMAND is executed, with ARGS as arguments."
+        ;;
+
+      finish)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=finish [LIBDIR]...
+
+Complete the installation of libtool libraries.
+
+Each LIBDIR is a directory that contains libtool libraries.
+
+The commands that this mode executes may require superuser privileges.  Use
+the '--dry-run' option if you just want to see what would be executed."
+        ;;
+
+      install)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=install INSTALL-COMMAND...
+
+Install executables or libraries.
+
+INSTALL-COMMAND is the installation command.  The first component should be
+either the 'install' or 'cp' program.
+
+The following components of INSTALL-COMMAND are treated specially:
+
+  -inst-prefix-dir PREFIX-DIR  Use PREFIX-DIR as a staging area for installation
+
+The rest of the components are interpreted as arguments to that command (only
+BSD-compatible install options are recognized)."
+        ;;
+
+      link)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=link LINK-COMMAND...
+
+Link object files or libraries together to form another library, or to
+create an executable program.
+
+LINK-COMMAND is a command using the C compiler that you would use to create
+a program from several object files.
+
+The following components of LINK-COMMAND are treated specially:
+
+  -all-static       do not do any dynamic linking at all
+  -avoid-version    do not add a version suffix if possible
+  -bindir BINDIR    specify path to binaries directory (for systems where
+                    libraries must be found in the PATH setting at runtime)
+  -dlopen FILE      '-dlpreopen' FILE if it cannot be dlopened at runtime
+  -dlpreopen FILE   link in FILE and add its symbols to lt_preloaded_symbols
+  -export-dynamic   allow symbols from OUTPUT-FILE to be resolved with dlsym(3)
+  -export-symbols SYMFILE
+                    try to export only the symbols listed in SYMFILE
+  -export-symbols-regex REGEX
+                    try to export only the symbols matching REGEX
+  -LLIBDIR          search LIBDIR for required installed libraries
+  -lNAME            OUTPUT-FILE requires the installed library libNAME
+  -module           build a library that can dlopened
+  -no-fast-install  disable the fast-install mode
+  -no-install       link a not-installable executable
+  -no-undefined     declare that a library does not refer to external symbols
+  -o OUTPUT-FILE    create OUTPUT-FILE from the specified objects
+  -objectlist FILE  use a list of object files found in FILE to specify objects
+  -os2dllname NAME  force a short DLL name on OS/2 (no effect on other OSes)
+  -precious-files-regex REGEX
+                    don't remove output files matching REGEX
+  -release RELEASE  specify package release information
+  -rpath LIBDIR     the created library will eventually be installed in LIBDIR
+  -R[ ]LIBDIR       add LIBDIR to the runtime path of programs and libraries
+  -shared           only do dynamic linking of libtool libraries
+  -shrext SUFFIX    override the standard shared library file extension
+  -static           do not do any dynamic linking of uninstalled libtool libraries
+  -static-libtool-libs
+                    do not do any dynamic linking of libtool libraries
+  -version-info CURRENT[:REVISION[:AGE]]
+                    specify library version info [each variable defaults to 0]
+  -weak LIBNAME     declare that the target provides the LIBNAME interface
+  -Wc,FLAG
+  -Xcompiler FLAG   pass linker-specific FLAG directly to the compiler
+  -Wa,FLAG
+  -Xassembler FLAG  pass linker-specific FLAG directly to the assembler
+  -Wl,FLAG
+  -Xlinker FLAG     pass linker-specific FLAG directly to the linker
+  -XCClinker FLAG   pass link-specific FLAG to the compiler driver (CC)
+
+All other options (arguments beginning with '-') are ignored.
+
+Every other argument is treated as a filename.  Files ending in '.la' are
+treated as uninstalled libtool libraries, other files are standard or library
+object files.
+
+If the OUTPUT-FILE ends in '.la', then a libtool library is created,
+only library objects ('.lo' files) may be specified, and '-rpath' is
+required, except when creating a convenience library.
+
+If OUTPUT-FILE ends in '.a' or '.lib', then a standard library is created
+using 'ar' and 'ranlib', or on Windows using 'lib'.
+
+If OUTPUT-FILE ends in '.lo' or '.$objext', then a reloadable object file
+is created, otherwise an executable program is created."
+        ;;
+
+      uninstall)
+        $ECHO \
+"Usage: $progname [OPTION]... --mode=uninstall RM [RM-OPTION]... FILE...
+
+Remove libraries from an installation directory.
+
+RM is the name of the program to use to delete files associated with each FILE
+(typically '/bin/rm').  RM-OPTIONS are options (such as '-f') to be passed
+to RM.
+
+If FILE is a libtool library, all the files associated with it are deleted.
+Otherwise, only FILE itself is deleted using RM."
+        ;;
+
+      *)
+        func_fatal_help "invalid operation mode '$opt_mode'"
+        ;;
+    esac
+
+    echo
+    $ECHO "Try '$progname --help' for more information about other modes."
+}
+
+# Now that we've collected a possible --mode arg, show help if necessary
+if $opt_help; then
+  if test : = "$opt_help"; then
+    func_mode_help
+  else
+    {
+      func_help noexit
+      for opt_mode in compile link execute install finish uninstall clean; do
+	func_mode_help
+      done
+    } | $SED -n '1p; 2,$s/^Usage:/  or: /p'
+    {
+      func_help noexit
+      for opt_mode in compile link execute install finish uninstall clean; do
+	echo
+	func_mode_help
+      done
+    } |
+    $SED '1d
+      /^When reporting/,/^Report/{
+	H
+	d
+      }
+      $x
+      /information about other modes/d
+      /more detailed .*MODE/d
+      s/^Usage:.*--mode=\([^ ]*\) .*/Description of \1 mode:/'
+  fi
+  exit $?
+fi
+
+
+# func_mode_execute arg...
+func_mode_execute ()
+{
+    $debug_cmd
+
+    # The first argument is the command name.
+    cmd=$nonopt
+    test -z "$cmd" && \
+      func_fatal_help "you must specify a COMMAND"
+
+    # Handle -dlopen flags immediately.
+    for file in $opt_dlopen; do
+      test -f "$file" \
+	|| func_fatal_help "'$file' is not a file"
+
+      dir=
+      case $file in
+      *.la)
+	func_resolve_sysroot "$file"
+	file=$func_resolve_sysroot_result
+
+	# Check to see that this really is a libtool archive.
+	func_lalib_unsafe_p "$file" \
+	  || func_fatal_help "'$lib' is not a valid libtool archive"
+
+	# Read the libtool library.
+	dlname=
+	library_names=
+	func_source "$file"
+
+	# Skip this library if it cannot be dlopened.
+	if test -z "$dlname"; then
+	  # Warn if it was a shared library.
+	  test -n "$library_names" && \
+	    func_warning "'$file' was not linked with '-export-dynamic'"
+	  continue
+	fi
+
+	func_dirname "$file" "" "."
+	dir=$func_dirname_result
+
+	if test -f "$dir/$objdir/$dlname"; then
+	  func_append dir "/$objdir"
+	else
+	  if test ! -f "$dir/$dlname"; then
+	    func_fatal_error "cannot find '$dlname' in '$dir' or '$dir/$objdir'"
+	  fi
+	fi
+	;;
+
+      *.lo)
+	# Just add the directory containing the .lo file.
+	func_dirname "$file" "" "."
+	dir=$func_dirname_result
+	;;
+
+      *)
+	func_warning "'-dlopen' is ignored for non-libtool libraries and objects"
+	continue
+	;;
+      esac
+
+      # Get the absolute pathname.
+      absdir=`cd "$dir" && pwd`
+      test -n "$absdir" && dir=$absdir
+
+      # Now add the directory to shlibpath_var.
+      if eval "test -z \"\$$shlibpath_var\""; then
+	eval "$shlibpath_var=\"\$dir\""
+      else
+	eval "$shlibpath_var=\"\$dir:\$$shlibpath_var\""
+      fi
+    done
+
+    # This variable tells wrapper scripts just to set shlibpath_var
+    # rather than running their programs.
+    libtool_execute_magic=$magic
+
+    # Check if any of the arguments is a wrapper script.
+    args=
+    for file
+    do
+      case $file in
+      -* | *.la | *.lo ) ;;
+      *)
+	# Do a test to see if this is really a libtool program.
+	if func_ltwrapper_script_p "$file"; then
+	  func_source "$file"
+	  # Transform arg to wrapped name.
+	  file=$progdir/$program
+	elif func_ltwrapper_executable_p "$file"; then
+	  func_ltwrapper_scriptname "$file"
+	  func_source "$func_ltwrapper_scriptname_result"
+	  # Transform arg to wrapped name.
+	  file=$progdir/$program
+	fi
+	;;
+      esac
+      # Quote arguments (to preserve shell metacharacters).
+      func_append_quoted args "$file"
+    done
+
+    if $opt_dry_run; then
+      # Display what would be done.
+      if test -n "$shlibpath_var"; then
+	eval "\$ECHO \"\$shlibpath_var=\$$shlibpath_var\""
+	echo "export $shlibpath_var"
+      fi
+      $ECHO "$cmd$args"
+      exit $EXIT_SUCCESS
+    else
+      if test -n "$shlibpath_var"; then
+	# Export the shlibpath_var.
+	eval "export $shlibpath_var"
+      fi
+
+      # Restore saved environment variables
+      for lt_var in LANG LANGUAGE LC_ALL LC_CTYPE LC_COLLATE LC_MESSAGES
+      do
+	eval "if test \"\${save_$lt_var+set}\" = set; then
+                $lt_var=\$save_$lt_var; export $lt_var
+	      else
+		$lt_unset $lt_var
+	      fi"
+      done
+
+      # Now prepare to actually exec the command.
+      exec_cmd=\$cmd$args
+    fi
+}
+
+test execute = "$opt_mode" && func_mode_execute ${1+"$@"}
+
+
+# func_mode_finish arg...
+func_mode_finish ()
+{
+    $debug_cmd
+
+    libs=
+    libdirs=
+    admincmds=
+
+    for opt in "$nonopt" ${1+"$@"}
+    do
+      if test -d "$opt"; then
+	func_append libdirs " $opt"
+
+      elif test -f "$opt"; then
+	if func_lalib_unsafe_p "$opt"; then
+	  func_append libs " $opt"
+	else
+	  func_warning "'$opt' is not a valid libtool archive"
+	fi
+
+      else
+	func_fatal_error "invalid argument '$opt'"
+      fi
+    done
+
+    if test -n "$libs"; then
+      if test -n "$lt_sysroot"; then
+        sysroot_regex=`$ECHO "$lt_sysroot" | $SED "$sed_make_literal_regex"`
+        sysroot_cmd="s/\([ ']\)$sysroot_regex/\1/g;"
+      else
+        sysroot_cmd=
+      fi
+
+      # Remove sysroot references
+      if $opt_dry_run; then
+        for lib in $libs; do
+          echo "removing references to $lt_sysroot and '=' prefixes from $lib"
+        done
+      else
+        tmpdir=`func_mktempdir`
+        for lib in $libs; do
+	  $SED -e "$sysroot_cmd s/\([ ']-[LR]\)=/\1/g; s/\([ ']\)=/\1/g" $lib \
+	    > $tmpdir/tmp-la
+	  mv -f $tmpdir/tmp-la $lib
+	done
+        ${RM}r "$tmpdir"
+      fi
+    fi
+
+    if test -n "$finish_cmds$finish_eval" && test -n "$libdirs"; then
+      for libdir in $libdirs; do
+	if test -n "$finish_cmds"; then
+	  # Do each command in the finish commands.
+	  func_execute_cmds "$finish_cmds" 'admincmds="$admincmds
+'"$cmd"'"'
+	fi
+	if test -n "$finish_eval"; then
+	  # Do the single finish_eval.
+	  eval cmds=\"$finish_eval\"
+	  $opt_dry_run || eval "$cmds" || func_append admincmds "
+       $cmds"
+	fi
+      done
+    fi
+
+    # Exit here if they wanted silent mode.
+    $opt_quiet && exit $EXIT_SUCCESS
+
+    if test -n "$finish_cmds$finish_eval" && test -n "$libdirs"; then
+      echo "----------------------------------------------------------------------"
+      echo "Libraries have been installed in:"
+      for libdir in $libdirs; do
+	$ECHO "   $libdir"
+      done
+      echo
+      echo "If you ever happen to want to link against installed libraries"
+      echo "in a given directory, LIBDIR, you must either use libtool, and"
+      echo "specify the full pathname of the library, or use the '-LLIBDIR'"
+      echo "flag during linking and do at least one of the following:"
+      if test -n "$shlibpath_var"; then
+	echo "   - add LIBDIR to the '$shlibpath_var' environment variable"
+	echo "     during execution"
+      fi
+      if test -n "$runpath_var"; then
+	echo "   - add LIBDIR to the '$runpath_var' environment variable"
+	echo "     during linking"
+      fi
+      if test -n "$hardcode_libdir_flag_spec"; then
+	libdir=LIBDIR
+	eval flag=\"$hardcode_libdir_flag_spec\"
+
+	$ECHO "   - use the '$flag' linker flag"
+      fi
+      if test -n "$admincmds"; then
+	$ECHO "   - have your system administrator run these commands:$admincmds"
+      fi
+      if test -f /etc/ld.so.conf; then
+	echo "   - have your system administrator add LIBDIR to '/etc/ld.so.conf'"
+      fi
+      echo
+
+      echo "See any operating system documentation about shared libraries for"
+      case $host in
+	solaris2.[6789]|solaris2.1[0-9])
+	  echo "more information, such as the ld(1), crle(1) and ld.so(8) manual"
+	  echo "pages."
+	  ;;
+	*)
+	  echo "more information, such as the ld(1) and ld.so(8) manual pages."
+	  ;;
+      esac
+      echo "----------------------------------------------------------------------"
+    fi
+    exit $EXIT_SUCCESS
+}
+
+test finish = "$opt_mode" && func_mode_finish ${1+"$@"}
+
+
+# func_mode_install arg...
+func_mode_install ()
+{
+    $debug_cmd
+
+    # There may be an optional sh(1) argument at the beginning of
+    # install_prog (especially on Windows NT).
+    if test "$SHELL" = "$nonopt" || test /bin/sh = "$nonopt" ||
+       # Allow the use of GNU shtool's install command.
+       case $nonopt in *shtool*) :;; *) false;; esac
+    then
+      # Aesthetically quote it.
+      func_quote_arg pretty "$nonopt"
+      install_prog="$func_quote_arg_result "
+      arg=$1
+      shift
+    else
+      install_prog=
+      arg=$nonopt
+    fi
+
+    # The real first argument should be the name of the installation program.
+    # Aesthetically quote it.
+    func_quote_arg pretty "$arg"
+    func_append install_prog "$func_quote_arg_result"
+    install_shared_prog=$install_prog
+    case " $install_prog " in
+      *[\\\ /]cp\ *) install_cp=: ;;
+      *) install_cp=false ;;
+    esac
+
+    # We need to accept at least all the BSD install flags.
+    dest=
+    files=
+    opts=
+    prev=
+    install_type=
+    isdir=false
+    stripme=
+    no_mode=:
+    for arg
+    do
+      arg2=
+      if test -n "$dest"; then
+	func_append files " $dest"
+	dest=$arg
+	continue
+      fi
+
+      case $arg in
+      -d) isdir=: ;;
+      -f)
+	if $install_cp; then :; else
+	  prev=$arg
+	fi
+	;;
+      -g | -m | -o)
+	prev=$arg
+	;;
+      -s)
+	stripme=" -s"
+	continue
+	;;
+      -*)
+	;;
+      *)
+	# If the previous option needed an argument, then skip it.
+	if test -n "$prev"; then
+	  if test X-m = "X$prev" && test -n "$install_override_mode"; then
+	    arg2=$install_override_mode
+	    no_mode=false
+	  fi
+	  prev=
+	else
+	  dest=$arg
+	  continue
+	fi
+	;;
+      esac
+
+      # Aesthetically quote the argument.
+      func_quote_arg pretty "$arg"
+      func_append install_prog " $func_quote_arg_result"
+      if test -n "$arg2"; then
+	func_quote_arg pretty "$arg2"
+      fi
+      func_append install_shared_prog " $func_quote_arg_result"
+    done
+
+    test -z "$install_prog" && \
+      func_fatal_help "you must specify an install program"
+
+    test -n "$prev" && \
+      func_fatal_help "the '$prev' option requires an argument"
+
+    if test -n "$install_override_mode" && $no_mode; then
+      if $install_cp; then :; else
+	func_quote_arg pretty "$install_override_mode"
+	func_append install_shared_prog " -m $func_quote_arg_result"
+      fi
+    fi
+
+    if test -z "$files"; then
+      if test -z "$dest"; then
+	func_fatal_help "no file or destination specified"
+      else
+	func_fatal_help "you must specify a destination"
+      fi
+    fi
+
+    # Strip any trailing slash from the destination.
+    func_stripname '' '/' "$dest"
+    dest=$func_stripname_result
+
+    # Check to see that the destination is a directory.
+    test -d "$dest" && isdir=:
+    if $isdir; then
+      destdir=$dest
+      destname=
+    else
+      func_dirname_and_basename "$dest" "" "."
+      destdir=$func_dirname_result
+      destname=$func_basename_result
+
+      # Not a directory, so check to see that there is only one file specified.
+      set dummy $files; shift
+      test "$#" -gt 1 && \
+	func_fatal_help "'$dest' is not a directory"
+    fi
+    case $destdir in
+    [\\/]* | [A-Za-z]:[\\/]*) ;;
+    *)
+      for file in $files; do
+	case $file in
+	*.lo) ;;
+	*)
+	  func_fatal_help "'$destdir' must be an absolute directory name"
+	  ;;
+	esac
+      done
+      ;;
+    esac
+
+    # This variable tells wrapper scripts just to set variables rather
+    # than running their programs.
+    libtool_install_magic=$magic
+
+    staticlibs=
+    future_libdirs=
+    current_libdirs=
+    for file in $files; do
+
+      # Do each installation.
+      case $file in
+      *.$libext)
+	# Do the static libraries later.
+	func_append staticlibs " $file"
+	;;
+
+      *.la)
+	func_resolve_sysroot "$file"
+	file=$func_resolve_sysroot_result
+
+	# Check to see that this really is a libtool archive.
+	func_lalib_unsafe_p "$file" \
+	  || func_fatal_help "'$file' is not a valid libtool archive"
+
+	library_names=
+	old_library=
+	relink_command=
+	func_source "$file"
+
+	# Add the libdir to current_libdirs if it is the destination.
+	if test "X$destdir" = "X$libdir"; then
+	  case "$current_libdirs " in
+	  *" $libdir "*) ;;
+	  *) func_append current_libdirs " $libdir" ;;
+	  esac
+	else
+	  # Note the libdir as a future libdir.
+	  case "$future_libdirs " in
+	  *" $libdir "*) ;;
+	  *) func_append future_libdirs " $libdir" ;;
+	  esac
+	fi
+
+	func_dirname "$file" "/" ""
+	dir=$func_dirname_result
+	func_append dir "$objdir"
+
+	if test -n "$relink_command"; then
+	  # Determine the prefix the user has applied to our future dir.
+	  inst_prefix_dir=`$ECHO "$destdir" | $SED -e "s%$libdir\$%%"`
+
+	  # Don't allow the user to place us outside of our expected
+	  # location b/c this prevents finding dependent libraries that
+	  # are installed to the same prefix.
+	  # At present, this check doesn't affect windows .dll's that
+	  # are installed into $libdir/../bin (currently, that works fine)
+	  # but it's something to keep an eye on.
+	  test "$inst_prefix_dir" = "$destdir" && \
+	    func_fatal_error "error: cannot install '$file' to a directory not ending in $libdir"
+
+	  if test -n "$inst_prefix_dir"; then
+	    # Stick the inst_prefix_dir data into the link command.
+	    relink_command=`$ECHO "$relink_command" | $SED "s%@inst_prefix_dir@%-inst-prefix-dir $inst_prefix_dir%"`
+	  else
+	    relink_command=`$ECHO "$relink_command" | $SED "s%@inst_prefix_dir@%%"`
+	  fi
+
+	  func_warning "relinking '$file'"
+	  func_show_eval "$relink_command" \
+	    'func_fatal_error "error: relink '\''$file'\'' with the above command before installing it"'
+	fi
+
+	# See the names of the shared library.
+	set dummy $library_names; shift
+	if test -n "$1"; then
+	  realname=$1
+	  shift
+
+	  srcname=$realname
+	  test -n "$relink_command" && srcname=${realname}T
+
+	  # Install the shared library and build the symlinks.
+	  func_show_eval "$install_shared_prog $dir/$srcname $destdir/$realname" \
+	      'exit $?'
+	  tstripme=$stripme
+	  case $host_os in
+	  cygwin* | mingw* | pw32* | cegcc*)
+	    case $realname in
+	    *.dll.a)
+	      tstripme=
+	      ;;
+	    esac
+	    ;;
+	  os2*)
+	    case $realname in
+	    *_dll.a)
+	      tstripme=
+	      ;;
+	    esac
+	    ;;
+	  esac
+	  if test -n "$tstripme" && test -n "$striplib"; then
+	    func_show_eval "$striplib $destdir/$realname" 'exit $?'
+	  fi
+
+	  if test "$#" -gt 0; then
+	    # Delete the old symlinks, and create new ones.
+	    # Try 'ln -sf' first, because the 'ln' binary might depend on
+	    # the symlink we replace!  Solaris /bin/ln does not understand -f,
+	    # so we also need to try rm && ln -s.
+	    for linkname
+	    do
+	      test "$linkname" != "$realname" \
+		&& func_show_eval "(cd $destdir && { $LN_S -f $realname $linkname || { $RM $linkname && $LN_S $realname $linkname; }; })"
+	    done
+	  fi
+
+	  # Do each command in the postinstall commands.
+	  lib=$destdir/$realname
+	  func_execute_cmds "$postinstall_cmds" 'exit $?'
+	fi
+
+	# Install the pseudo-library for information purposes.
+	func_basename "$file"
+	name=$func_basename_result
+	instname=$dir/${name}i
+	func_show_eval "$install_prog $instname $destdir/$name" 'exit $?'
+
+	# Maybe install the static library, too.
+	test -n "$old_library" && func_append staticlibs " $dir/$old_library"
+	;;
+
+      *.lo)
+	# Install (i.e. copy) a libtool object.
+
+	# Figure out destination file name, if it wasn't already specified.
+	if test -n "$destname"; then
+	  destfile=$destdir/$destname
+	else
+	  func_basename "$file"
+	  destfile=$func_basename_result
+	  destfile=$destdir/$destfile
+	fi
+
+	# Deduce the name of the destination old-style object file.
+	case $destfile in
+	*.lo)
+	  func_lo2o "$destfile"
+	  staticdest=$func_lo2o_result
+	  ;;
+	*.$objext)
+	  staticdest=$destfile
+	  destfile=
+	  ;;
+	*)
+	  func_fatal_help "cannot copy a libtool object to '$destfile'"
+	  ;;
+	esac
+
+	# Install the libtool object if requested.
+	test -n "$destfile" && \
+	  func_show_eval "$install_prog $file $destfile" 'exit $?'
+
+	# Install the old object if enabled.
+	if test yes = "$build_old_libs"; then
+	  # Deduce the name of the old-style object file.
+	  func_lo2o "$file"
+	  staticobj=$func_lo2o_result
+	  func_show_eval "$install_prog \$staticobj \$staticdest" 'exit $?'
+	fi
+	exit $EXIT_SUCCESS
+	;;
+
+      *)
+	# Figure out destination file name, if it wasn't already specified.
+	if test -n "$destname"; then
+	  destfile=$destdir/$destname
+	else
+	  func_basename "$file"
+	  destfile=$func_basename_result
+	  destfile=$destdir/$destfile
+	fi
+
+	# If the file is missing, and there is a .exe on the end, strip it
+	# because it is most likely a libtool script we actually want to
+	# install
+	stripped_ext=
+	case $file in
+	  *.exe)
+	    if test ! -f "$file"; then
+	      func_stripname '' '.exe' "$file"
+	      file=$func_stripname_result
+	      stripped_ext=.exe
+	    fi
+	    ;;
+	esac
+
+	# Do a test to see if this is really a libtool program.
+	case $host in
+	*cygwin* | *mingw*)
+	    if func_ltwrapper_executable_p "$file"; then
+	      func_ltwrapper_scriptname "$file"
+	      wrapper=$func_ltwrapper_scriptname_result
+	    else
+	      func_stripname '' '.exe' "$file"
+	      wrapper=$func_stripname_result
+	    fi
+	    ;;
+	*)
+	    wrapper=$file
+	    ;;
+	esac
+	if func_ltwrapper_script_p "$wrapper"; then
+	  notinst_deplibs=
+	  relink_command=
+
+	  func_source "$wrapper"
+
+	  # Check the variables that should have been set.
+	  test -z "$generated_by_libtool_version" && \
+	    func_fatal_error "invalid libtool wrapper script '$wrapper'"
+
+	  finalize=:
+	  for lib in $notinst_deplibs; do
+	    # Check to see that each library is installed.
+	    libdir=
+	    if test -f "$lib"; then
+	      func_source "$lib"
+	    fi
+	    libfile=$libdir/`$ECHO "$lib" | $SED 's%^.*/%%g'`
+	    if test -n "$libdir" && test ! -f "$libfile"; then
+	      func_warning "'$lib' has not been installed in '$libdir'"
+	      finalize=false
+	    fi
+	  done
+
+	  relink_command=
+	  func_source "$wrapper"
+
+	  outputname=
+	  if test no = "$fast_install" && test -n "$relink_command"; then
+	    $opt_dry_run || {
+	      if $finalize; then
+	        tmpdir=`func_mktempdir`
+		func_basename "$file$stripped_ext"
+		file=$func_basename_result
+	        outputname=$tmpdir/$file
+	        # Replace the output file specification.
+	        relink_command=`$ECHO "$relink_command" | $SED 's%@OUTPUT@%'"$outputname"'%g'`
+
+	        $opt_quiet || {
+	          func_quote_arg expand,pretty "$relink_command"
+		  eval "func_echo $func_quote_arg_result"
+	        }
+	        if eval "$relink_command"; then :
+	          else
+		  func_error "error: relink '$file' with the above command before installing it"
+		  $opt_dry_run || ${RM}r "$tmpdir"
+		  continue
+	        fi
+	        file=$outputname
+	      else
+	        func_warning "cannot relink '$file'"
+	      fi
+	    }
+	  else
+	    # Install the binary that we compiled earlier.
+	    file=`$ECHO "$file$stripped_ext" | $SED "s%\([^/]*\)$%$objdir/\1%"`
+	  fi
+	fi
+
+	# remove .exe since cygwin /usr/bin/install will append another
+	# one anyway
+	case $install_prog,$host in
+	*/usr/bin/install*,*cygwin*)
+	  case $file:$destfile in
+	  *.exe:*.exe)
+	    # this is ok
+	    ;;
+	  *.exe:*)
+	    destfile=$destfile.exe
+	    ;;
+	  *:*.exe)
+	    func_stripname '' '.exe' "$destfile"
+	    destfile=$func_stripname_result
+	    ;;
+	  esac
+	  ;;
+	esac
+	func_show_eval "$install_prog\$stripme \$file \$destfile" 'exit $?'
+	$opt_dry_run || if test -n "$outputname"; then
+	  ${RM}r "$tmpdir"
+	fi
+	;;
+      esac
+    done
+
+    for file in $staticlibs; do
+      func_basename "$file"
+      name=$func_basename_result
+
+      # Set up the ranlib parameters.
+      oldlib=$destdir/$name
+      func_to_tool_file "$oldlib" func_convert_file_msys_to_w32
+      tool_oldlib=$func_to_tool_file_result
+
+      func_show_eval "$install_prog \$file \$oldlib" 'exit $?'
+
+      if test -n "$stripme" && test -n "$old_striplib"; then
+	func_show_eval "$old_striplib $tool_oldlib" 'exit $?'
+      fi
+
+      # Do each command in the postinstall commands.
+      func_execute_cmds "$old_postinstall_cmds" 'exit $?'
+    done
+
+    test -n "$future_libdirs" && \
+      func_warning "remember to run '$progname --finish$future_libdirs'"
+
+    if test -n "$current_libdirs"; then
+      # Maybe just do a dry run.
+      $opt_dry_run && current_libdirs=" -n$current_libdirs"
+      exec_cmd='$SHELL "$progpath" $preserve_args --finish$current_libdirs'
+    else
+      exit $EXIT_SUCCESS
+    fi
+}
+
+test install = "$opt_mode" && func_mode_install ${1+"$@"}
+
+
+# func_generate_dlsyms outputname originator pic_p
+# Extract symbols from dlprefiles and create ${outputname}S.o with
+# a dlpreopen symbol table.
+func_generate_dlsyms ()
+{
+    $debug_cmd
+
+    my_outputname=$1
+    my_originator=$2
+    my_pic_p=${3-false}
+    my_prefix=`$ECHO "$my_originator" | $SED 's%[^a-zA-Z0-9]%_%g'`
+    my_dlsyms=
+
+    if test -n "$dlfiles$dlprefiles" || test no != "$dlself"; then
+      if test -n "$NM" && test -n "$global_symbol_pipe"; then
+	my_dlsyms=${my_outputname}S.c
+      else
+	func_error "not configured to extract global symbols from dlpreopened files"
+      fi
+    fi
+
+    if test -n "$my_dlsyms"; then
+      case $my_dlsyms in
+      "") ;;
+      *.c)
+	# Discover the nlist of each of the dlfiles.
+	nlist=$output_objdir/$my_outputname.nm
+
+	func_show_eval "$RM $nlist ${nlist}S ${nlist}T"
+
+	# Parse the name list into a source file.
+	func_verbose "creating $output_objdir/$my_dlsyms"
+
+	$opt_dry_run || $ECHO > "$output_objdir/$my_dlsyms" "\
+/* $my_dlsyms - symbol resolution table for '$my_outputname' dlsym emulation. */
+/* Generated by $PROGRAM (GNU $PACKAGE) $VERSION */
+
+#ifdef __cplusplus
+extern \"C\" {
+#endif
+
+#if defined __GNUC__ && (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 4)) || (__GNUC__ > 4))
+#pragma GCC diagnostic ignored \"-Wstrict-prototypes\"
+#endif
+
+/* Keep this code in sync between libtool.m4, ltmain, lt_system.h, and tests.  */
+#if defined _WIN32 || defined __CYGWIN__ || defined _WIN32_WCE
+/* DATA imports from DLLs on WIN32 can't be const, because runtime
+   relocations are performed -- see ld's documentation on pseudo-relocs.  */
+# define LT_DLSYM_CONST
+#elif defined __osf__
+/* This system does not cope well with relocations in const data.  */
+# define LT_DLSYM_CONST
+#else
+# define LT_DLSYM_CONST const
+#endif
+
+#define STREQ(s1, s2) (strcmp ((s1), (s2)) == 0)
+
+/* External symbol declarations for the compiler. */\
+"
+
+	if test yes = "$dlself"; then
+	  func_verbose "generating symbol list for '$output'"
+
+	  $opt_dry_run || echo ': @PROGRAM@ ' > "$nlist"
+
+	  # Add our own program objects to the symbol list.
+	  progfiles=`$ECHO "$objs$old_deplibs" | $SP2NL | $SED "$lo2o" | $NL2SP`
+	  for progfile in $progfiles; do
+	    func_to_tool_file "$progfile" func_convert_file_msys_to_w32
+	    func_verbose "extracting global C symbols from '$func_to_tool_file_result'"
+	    $opt_dry_run || eval "$NM $func_to_tool_file_result | $global_symbol_pipe >> '$nlist'"
+	  done
+
+	  if test -n "$exclude_expsyms"; then
+	    $opt_dry_run || {
+	      eval '$EGREP -v " ($exclude_expsyms)$" "$nlist" > "$nlist"T'
+	      eval '$MV "$nlist"T "$nlist"'
+	    }
+	  fi
+
+	  if test -n "$export_symbols_regex"; then
+	    $opt_dry_run || {
+	      eval '$EGREP -e "$export_symbols_regex" "$nlist" > "$nlist"T'
+	      eval '$MV "$nlist"T "$nlist"'
+	    }
+	  fi
+
+	  # Prepare the list of exported symbols
+	  if test -z "$export_symbols"; then
+	    export_symbols=$output_objdir/$outputname.exp
+	    $opt_dry_run || {
+	      $RM $export_symbols
+	      eval "$SED -n -e '/^: @PROGRAM@ $/d' -e 's/^.* \(.*\)$/\1/p' "'< "$nlist" > "$export_symbols"'
+	      case $host in
+	      *cygwin* | *mingw* | *cegcc* )
+                eval "echo EXPORTS "'> "$output_objdir/$outputname.def"'
+                eval 'cat "$export_symbols" >> "$output_objdir/$outputname.def"'
+	        ;;
+	      esac
+	    }
+	  else
+	    $opt_dry_run || {
+	      eval "$SED -e 's/\([].[*^$]\)/\\\\\1/g' -e 's/^/ /' -e 's/$/$/'"' < "$export_symbols" > "$output_objdir/$outputname.exp"'
+	      eval '$GREP -f "$output_objdir/$outputname.exp" < "$nlist" > "$nlist"T'
+	      eval '$MV "$nlist"T "$nlist"'
+	      case $host in
+	        *cygwin* | *mingw* | *cegcc* )
+	          eval "echo EXPORTS "'> "$output_objdir/$outputname.def"'
+	          eval 'cat "$nlist" >> "$output_objdir/$outputname.def"'
+	          ;;
+	      esac
+	    }
+	  fi
+	fi
+
+	for dlprefile in $dlprefiles; do
+	  func_verbose "extracting global C symbols from '$dlprefile'"
+	  func_basename "$dlprefile"
+	  name=$func_basename_result
+          case $host in
+	    *cygwin* | *mingw* | *cegcc* )
+	      # if an import library, we need to obtain dlname
+	      if func_win32_import_lib_p "$dlprefile"; then
+	        func_tr_sh "$dlprefile"
+	        eval "curr_lafile=\$libfile_$func_tr_sh_result"
+	        dlprefile_dlbasename=
+	        if test -n "$curr_lafile" && func_lalib_p "$curr_lafile"; then
+	          # Use subshell, to avoid clobbering current variable values
+	          dlprefile_dlname=`source "$curr_lafile" && echo "$dlname"`
+	          if test -n "$dlprefile_dlname"; then
+	            func_basename "$dlprefile_dlname"
+	            dlprefile_dlbasename=$func_basename_result
+	          else
+	            # no lafile. user explicitly requested -dlpreopen <import library>.
+	            $sharedlib_from_linklib_cmd "$dlprefile"
+	            dlprefile_dlbasename=$sharedlib_from_linklib_result
+	          fi
+	        fi
+	        $opt_dry_run || {
+	          if test -n "$dlprefile_dlbasename"; then
+	            eval '$ECHO ": $dlprefile_dlbasename" >> "$nlist"'
+	          else
+	            func_warning "Could not compute DLL name from $name"
+	            eval '$ECHO ": $name " >> "$nlist"'
+	          fi
+	          func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
+	          eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe |
+	            $SED -e '/I __imp/d' -e 's/I __nm_/D /;s/_nm__//' >> '$nlist'"
+	        }
+	      else # not an import lib
+	        $opt_dry_run || {
+	          eval '$ECHO ": $name " >> "$nlist"'
+	          func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
+	          eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe >> '$nlist'"
+	        }
+	      fi
+	    ;;
+	    *)
+	      $opt_dry_run || {
+	        eval '$ECHO ": $name " >> "$nlist"'
+	        func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
+	        eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe >> '$nlist'"
+	      }
+	    ;;
+          esac
+	done
+
+	$opt_dry_run || {
+	  # Make sure we have at least an empty file.
+	  test -f "$nlist" || : > "$nlist"
+
+	  if test -n "$exclude_expsyms"; then
+	    $EGREP -v " ($exclude_expsyms)$" "$nlist" > "$nlist"T
+	    $MV "$nlist"T "$nlist"
+	  fi
+
+	  # Try sorting and uniquifying the output.
+	  if $GREP -v "^: " < "$nlist" |
+	      if sort -k 3 </dev/null >/dev/null 2>&1; then
+		sort -k 3
+	      else
+		sort +2
+	      fi |
+	      uniq > "$nlist"S; then
+	    :
+	  else
+	    $GREP -v "^: " < "$nlist" > "$nlist"S
+	  fi
+
+	  if test -f "$nlist"S; then
+	    eval "$global_symbol_to_cdecl"' < "$nlist"S >> "$output_objdir/$my_dlsyms"'
+	  else
+	    echo '/* NONE */' >> "$output_objdir/$my_dlsyms"
+	  fi
+
+	  func_show_eval '$RM "${nlist}I"'
+	  if test -n "$global_symbol_to_import"; then
+	    eval "$global_symbol_to_import"' < "$nlist"S > "$nlist"I'
+	  fi
+
+	  echo >> "$output_objdir/$my_dlsyms" "\
+
+/* The mapping between symbol names and symbols.  */
+typedef struct {
+  const char *name;
+  void *address;
+} lt_dlsymlist;
+extern LT_DLSYM_CONST lt_dlsymlist
+lt_${my_prefix}_LTX_preloaded_symbols[];\
+"
+
+	  if test -s "$nlist"I; then
+	    echo >> "$output_objdir/$my_dlsyms" "\
+static void lt_syminit(void)
+{
+  LT_DLSYM_CONST lt_dlsymlist *symbol = lt_${my_prefix}_LTX_preloaded_symbols;
+  for (; symbol->name; ++symbol)
+    {"
+	    $SED 's/.*/      if (STREQ (symbol->name, \"&\")) symbol->address = (void *) \&&;/' < "$nlist"I >> "$output_objdir/$my_dlsyms"
+	    echo >> "$output_objdir/$my_dlsyms" "\
+    }
+}"
+	  fi
+	  echo >> "$output_objdir/$my_dlsyms" "\
+LT_DLSYM_CONST lt_dlsymlist
+lt_${my_prefix}_LTX_preloaded_symbols[] =
+{ {\"$my_originator\", (void *) 0},"
+
+	  if test -s "$nlist"I; then
+	    echo >> "$output_objdir/$my_dlsyms" "\
+  {\"@INIT@\", (void *) &lt_syminit},"
+	  fi
+
+	  case $need_lib_prefix in
+	  no)
+	    eval "$global_symbol_to_c_name_address" < "$nlist" >> "$output_objdir/$my_dlsyms"
+	    ;;
+	  *)
+	    eval "$global_symbol_to_c_name_address_lib_prefix" < "$nlist" >> "$output_objdir/$my_dlsyms"
+	    ;;
+	  esac
+	  echo >> "$output_objdir/$my_dlsyms" "\
+  {0, (void *) 0}
+};
+
+/* This works around a problem in FreeBSD linker */
+#ifdef FREEBSD_WORKAROUND
+static const void *lt_preloaded_setup() {
+  return lt_${my_prefix}_LTX_preloaded_symbols;
+}
+#endif
+
+#ifdef __cplusplus
+}
+#endif\
+"
+	} # !$opt_dry_run
+
+	pic_flag_for_symtable=
+	case "$compile_command " in
+	*" -static "*) ;;
+	*)
+	  case $host in
+	  # compiling the symbol table file with pic_flag works around
+	  # a FreeBSD bug that causes programs to crash when -lm is
+	  # linked before any other PIC object.  But we must not use
+	  # pic_flag when linking with -static.  The problem exists in
+	  # FreeBSD 2.2.6 and is fixed in FreeBSD 3.1.
+	  *-*-freebsd2.*|*-*-freebsd3.0*|*-*-freebsdelf3.0*)
+	    pic_flag_for_symtable=" $pic_flag -DFREEBSD_WORKAROUND" ;;
+	  *-*-hpux*)
+	    pic_flag_for_symtable=" $pic_flag"  ;;
+	  *)
+	    $my_pic_p && pic_flag_for_symtable=" $pic_flag"
+	    ;;
+	  esac
+	  ;;
+	esac
+	symtab_cflags=
+	for arg in $LTCFLAGS; do
+	  case $arg in
+	  -pie | -fpie | -fPIE) ;;
+	  *) func_append symtab_cflags " $arg" ;;
+	  esac
+	done
+
+	# Now compile the dynamic symbol file.
+	func_show_eval '(cd $output_objdir && $LTCC$symtab_cflags -c$no_builtin_flag$pic_flag_for_symtable "$my_dlsyms")' 'exit $?'
+
+	# Clean up the generated files.
+	func_show_eval '$RM "$output_objdir/$my_dlsyms" "$nlist" "${nlist}S" "${nlist}T" "${nlist}I"'
+
+	# Transform the symbol file into the correct name.
+	symfileobj=$output_objdir/${my_outputname}S.$objext
+	case $host in
+	*cygwin* | *mingw* | *cegcc* )
+	  if test -f "$output_objdir/$my_outputname.def"; then
+	    compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$output_objdir/$my_outputname.def $symfileobj%"`
+	    finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$output_objdir/$my_outputname.def $symfileobj%"`
+	  else
+	    compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$symfileobj%"`
+	    finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$symfileobj%"`
+	  fi
+	  ;;
+	*)
+	  compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$symfileobj%"`
+	  finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$symfileobj%"`
+	  ;;
+	esac
+	;;
+      *)
+	func_fatal_error "unknown suffix for '$my_dlsyms'"
+	;;
+      esac
+    else
+      # We keep going just in case the user didn't refer to
+      # lt_preloaded_symbols.  The linker will fail if global_symbol_pipe
+      # really was required.
+
+      # Nullify the symbol file.
+      compile_command=`$ECHO "$compile_command" | $SED "s% @SYMFILE@%%"`
+      finalize_command=`$ECHO "$finalize_command" | $SED "s% @SYMFILE@%%"`
+    fi
+}
+
+# func_cygming_gnu_implib_p ARG
+# This predicate returns with zero status (TRUE) if
+# ARG is a GNU/binutils-style import library. Returns
+# with nonzero status (FALSE) otherwise.
+func_cygming_gnu_implib_p ()
+{
+  $debug_cmd
+
+  func_to_tool_file "$1" func_convert_file_msys_to_w32
+  func_cygming_gnu_implib_tmp=`$NM "$func_to_tool_file_result" | eval "$global_symbol_pipe" | $EGREP ' (_head_[A-Za-z0-9_]+_[ad]l*|[A-Za-z0-9_]+_[ad]l*_iname)$'`
+  test -n "$func_cygming_gnu_implib_tmp"
+}
+
+# func_cygming_ms_implib_p ARG
+# This predicate returns with zero status (TRUE) if
+# ARG is an MS-style import library. Returns
+# with nonzero status (FALSE) otherwise.
+func_cygming_ms_implib_p ()
+{
+  $debug_cmd
+
+  func_to_tool_file "$1" func_convert_file_msys_to_w32
+  func_cygming_ms_implib_tmp=`$NM "$func_to_tool_file_result" | eval "$global_symbol_pipe" | $GREP '_NULL_IMPORT_DESCRIPTOR'`
+  test -n "$func_cygming_ms_implib_tmp"
+}
+
+# func_win32_libid arg
+# return the library type of file 'arg'
+#
+# Need a lot of goo to handle *both* DLLs and import libs
+# Has to be a shell function in order to 'eat' the argument
+# that is supplied when $file_magic_command is called.
+# Despite the name, also deal with 64 bit binaries.
+func_win32_libid ()
+{
+  $debug_cmd
+
+  win32_libid_type=unknown
+  win32_fileres=`file -L $1 2>/dev/null`
+  case $win32_fileres in
+  *ar\ archive\ import\ library*) # definitely import
+    win32_libid_type="x86 archive import"
+    ;;
+  *ar\ archive*) # could be an import, or static
+    # Keep the egrep pattern in sync with the one in _LT_CHECK_MAGIC_METHOD.
+    if eval $OBJDUMP -f $1 | $SED -e '10q' 2>/dev/null |
+       $EGREP 'file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)' >/dev/null; then
+      case $nm_interface in
+      "MS dumpbin")
+	if func_cygming_ms_implib_p "$1" ||
+	   func_cygming_gnu_implib_p "$1"
+	then
+	  win32_nmres=import
+	else
+	  win32_nmres=
+	fi
+	;;
+      *)
+	func_to_tool_file "$1" func_convert_file_msys_to_w32
+	win32_nmres=`eval $NM -f posix -A \"$func_to_tool_file_result\" |
+	  $SED -n -e '
+	    1,100{
+		/ I /{
+		    s|.*|import|
+		    p
+		    q
+		}
+	    }'`
+	;;
+      esac
+      case $win32_nmres in
+      import*)  win32_libid_type="x86 archive import";;
+      *)        win32_libid_type="x86 archive static";;
+      esac
+    fi
+    ;;
+  *DLL*)
+    win32_libid_type="x86 DLL"
+    ;;
+  *executable*) # but shell scripts are "executable" too...
+    case $win32_fileres in
+    *MS\ Windows\ PE\ Intel*)
+      win32_libid_type="x86 DLL"
+      ;;
+    esac
+    ;;
+  esac
+  $ECHO "$win32_libid_type"
+}
+
+# func_cygming_dll_for_implib ARG
+#
+# Platform-specific function to extract the
+# name of the DLL associated with the specified
+# import library ARG.
+# Invoked by eval'ing the libtool variable
+#    $sharedlib_from_linklib_cmd
+# Result is available in the variable
+#    $sharedlib_from_linklib_result
+func_cygming_dll_for_implib ()
+{
+  $debug_cmd
+
+  sharedlib_from_linklib_result=`$DLLTOOL --identify-strict --identify "$1"`
+}
+
+# func_cygming_dll_for_implib_fallback_core SECTION_NAME LIBNAMEs
+#
+# The is the core of a fallback implementation of a
+# platform-specific function to extract the name of the
+# DLL associated with the specified import library LIBNAME.
+#
+# SECTION_NAME is either .idata$6 or .idata$7, depending
+# on the platform and compiler that created the implib.
+#
+# Echos the name of the DLL associated with the
+# specified import library.
+func_cygming_dll_for_implib_fallback_core ()
+{
+  $debug_cmd
+
+  match_literal=`$ECHO "$1" | $SED "$sed_make_literal_regex"`
+  $OBJDUMP -s --section "$1" "$2" 2>/dev/null |
+    $SED '/^Contents of section '"$match_literal"':/{
+      # Place marker at beginning of archive member dllname section
+      s/.*/====MARK====/
+      p
+      d
+    }
+    # These lines can sometimes be longer than 43 characters, but
+    # are always uninteresting
+    /:[	 ]*file format pe[i]\{,1\}-/d
+    /^In archive [^:]*:/d
+    # Ensure marker is printed
+    /^====MARK====/p
+    # Remove all lines with less than 43 characters
+    /^.\{43\}/!d
+    # From remaining lines, remove first 43 characters
+    s/^.\{43\}//' |
+    $SED -n '
+      # Join marker and all lines until next marker into a single line
+      /^====MARK====/ b para
+      H
+      $ b para
+      b
+      :para
+      x
+      s/\n//g
+      # Remove the marker
+      s/^====MARK====//
+      # Remove trailing dots and whitespace
+      s/[\. \t]*$//
+      # Print
+      /./p' |
+    # we now have a list, one entry per line, of the stringified
+    # contents of the appropriate section of all members of the
+    # archive that possess that section. Heuristic: eliminate
+    # all those that have a first or second character that is
+    # a '.' (that is, objdump's representation of an unprintable
+    # character.) This should work for all archives with less than
+    # 0x302f exports -- but will fail for DLLs whose name actually
+    # begins with a literal '.' or a single character followed by
+    # a '.'.
+    #
+    # Of those that remain, print the first one.
+    $SED -e '/^\./d;/^.\./d;q'
+}
+
+# func_cygming_dll_for_implib_fallback ARG
+# Platform-specific function to extract the
+# name of the DLL associated with the specified
+# import library ARG.
+#
+# This fallback implementation is for use when $DLLTOOL
+# does not support the --identify-strict option.
+# Invoked by eval'ing the libtool variable
+#    $sharedlib_from_linklib_cmd
+# Result is available in the variable
+#    $sharedlib_from_linklib_result
+func_cygming_dll_for_implib_fallback ()
+{
+  $debug_cmd
+
+  if func_cygming_gnu_implib_p "$1"; then
+    # binutils import library
+    sharedlib_from_linklib_result=`func_cygming_dll_for_implib_fallback_core '.idata$7' "$1"`
+  elif func_cygming_ms_implib_p "$1"; then
+    # ms-generated import library
+    sharedlib_from_linklib_result=`func_cygming_dll_for_implib_fallback_core '.idata$6' "$1"`
+  else
+    # unknown
+    sharedlib_from_linklib_result=
+  fi
+}
+
+
+# func_extract_an_archive dir oldlib
+func_extract_an_archive ()
+{
+    $debug_cmd
+
+    f_ex_an_ar_dir=$1; shift
+    f_ex_an_ar_oldlib=$1
+    if test yes = "$lock_old_archive_extraction"; then
+      lockfile=$f_ex_an_ar_oldlib.lock
+      until $opt_dry_run || ln "$progpath" "$lockfile" 2>/dev/null; do
+	func_echo "Waiting for $lockfile to be removed"
+	sleep 2
+      done
+    fi
+    func_show_eval "(cd \$f_ex_an_ar_dir && $AR x \"\$f_ex_an_ar_oldlib\")" \
+		   'stat=$?; rm -f "$lockfile"; exit $stat'
+    if test yes = "$lock_old_archive_extraction"; then
+      $opt_dry_run || rm -f "$lockfile"
+    fi
+    if ($AR t "$f_ex_an_ar_oldlib" | sort | sort -uc >/dev/null 2>&1); then
+     :
+    else
+      func_fatal_error "object name conflicts in archive: $f_ex_an_ar_dir/$f_ex_an_ar_oldlib"
+    fi
+}
+
+
+# func_extract_archives gentop oldlib ...
+func_extract_archives ()
+{
+    $debug_cmd
+
+    my_gentop=$1; shift
+    my_oldlibs=${1+"$@"}
+    my_oldobjs=
+    my_xlib=
+    my_xabs=
+    my_xdir=
+
+    for my_xlib in $my_oldlibs; do
+      # Extract the objects.
+      case $my_xlib in
+	[\\/]* | [A-Za-z]:[\\/]*) my_xabs=$my_xlib ;;
+	*) my_xabs=`pwd`"/$my_xlib" ;;
+      esac
+      func_basename "$my_xlib"
+      my_xlib=$func_basename_result
+      my_xlib_u=$my_xlib
+      while :; do
+        case " $extracted_archives " in
+	*" $my_xlib_u "*)
+	  func_arith $extracted_serial + 1
+	  extracted_serial=$func_arith_result
+	  my_xlib_u=lt$extracted_serial-$my_xlib ;;
+	*) break ;;
+	esac
+      done
+      extracted_archives="$extracted_archives $my_xlib_u"
+      my_xdir=$my_gentop/$my_xlib_u
+
+      func_mkdir_p "$my_xdir"
+
+      case $host in
+      *-darwin*)
+	func_verbose "Extracting $my_xabs"
+	# Do not bother doing anything if just a dry run
+	$opt_dry_run || {
+	  darwin_orig_dir=`pwd`
+	  cd $my_xdir || exit $?
+	  darwin_archive=$my_xabs
+	  darwin_curdir=`pwd`
+	  func_basename "$darwin_archive"
+	  darwin_base_archive=$func_basename_result
+	  darwin_arches=`$LIPO -info "$darwin_archive" 2>/dev/null | $GREP Architectures 2>/dev/null || true`
+	  if test -n "$darwin_arches"; then
+	    darwin_arches=`$ECHO "$darwin_arches" | $SED -e 's/.*are://'`
+	    darwin_arch=
+	    func_verbose "$darwin_base_archive has multiple architectures $darwin_arches"
+	    for darwin_arch in  $darwin_arches; do
+	      func_mkdir_p "unfat-$$/$darwin_base_archive-$darwin_arch"
+	      $LIPO -thin $darwin_arch -output "unfat-$$/$darwin_base_archive-$darwin_arch/$darwin_base_archive" "$darwin_archive"
+	      cd "unfat-$$/$darwin_base_archive-$darwin_arch"
+	      func_extract_an_archive "`pwd`" "$darwin_base_archive"
+	      cd "$darwin_curdir"
+	      $RM "unfat-$$/$darwin_base_archive-$darwin_arch/$darwin_base_archive"
+	    done # $darwin_arches
+            ## Okay now we've a bunch of thin objects, gotta fatten them up :)
+	    darwin_filelist=`find unfat-$$ -type f -name \*.o -print -o -name \*.lo -print | $SED -e "$sed_basename" | sort -u`
+	    darwin_file=
+	    darwin_files=
+	    for darwin_file in $darwin_filelist; do
+	      darwin_files=`find unfat-$$ -name $darwin_file -print | sort | $NL2SP`
+	      $LIPO -create -output "$darwin_file" $darwin_files
+	    done # $darwin_filelist
+	    $RM -rf unfat-$$
+	    cd "$darwin_orig_dir"
+	  else
+	    cd $darwin_orig_dir
+	    func_extract_an_archive "$my_xdir" "$my_xabs"
+	  fi # $darwin_arches
+	} # !$opt_dry_run
+	;;
+      *)
+        func_extract_an_archive "$my_xdir" "$my_xabs"
+	;;
+      esac
+      my_oldobjs="$my_oldobjs "`find $my_xdir -name \*.$objext -print -o -name \*.lo -print | sort | $NL2SP`
+    done
+
+    func_extract_archives_result=$my_oldobjs
+}
+
+
+# func_emit_wrapper [arg=no]
+#
+# Emit a libtool wrapper script on stdout.
+# Don't directly open a file because we may want to
+# incorporate the script contents within a cygwin/mingw
+# wrapper executable.  Must ONLY be called from within
+# func_mode_link because it depends on a number of variables
+# set therein.
+#
+# ARG is the value that the WRAPPER_SCRIPT_BELONGS_IN_OBJDIR
+# variable will take.  If 'yes', then the emitted script
+# will assume that the directory where it is stored is
+# the $objdir directory.  This is a cygwin/mingw-specific
+# behavior.
+func_emit_wrapper ()
+{
+	func_emit_wrapper_arg1=${1-no}
+
+	$ECHO "\
+#! $SHELL
+
+# $output - temporary wrapper script for $objdir/$outputname
+# Generated by $PROGRAM (GNU $PACKAGE) $VERSION
+#
+# The $output program cannot be directly executed until all the libtool
+# libraries that it depends on are installed.
+#
+# This wrapper script should never be moved out of the build directory.
+# If it is, it will not operate correctly.
+
+# Sed substitution that helps us do robust quoting.  It backslashifies
+# metacharacters that are still active within double-quoted strings.
+sed_quote_subst='$sed_quote_subst'
+
+# Be Bourne compatible
+if test -n \"\${ZSH_VERSION+set}\" && (emulate sh) >/dev/null 2>&1; then
+  emulate sh
+  NULLCMD=:
+  # Zsh 3.x and 4.x performs word splitting on \${1+\"\$@\"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '\${1+\"\$@\"}'='\"\$@\"'
+  setopt NO_GLOB_SUBST
+else
+  case \`(set -o) 2>/dev/null\` in *posix*) set -o posix;; esac
+fi
+BIN_SH=xpg4; export BIN_SH # for Tru64
+DUALCASE=1; export DUALCASE # for MKS sh
+
+# The HP-UX ksh and POSIX shell print the target directory to stdout
+# if CDPATH is set.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+relink_command=\"$relink_command\"
+
+# This environment variable determines our operation mode.
+if test \"\$libtool_install_magic\" = \"$magic\"; then
+  # install mode needs the following variables:
+  generated_by_libtool_version='$macro_version'
+  notinst_deplibs='$notinst_deplibs'
+else
+  # When we are sourced in execute mode, \$file and \$ECHO are already set.
+  if test \"\$libtool_execute_magic\" != \"$magic\"; then
+    file=\"\$0\""
+
+    func_quote_arg pretty "$ECHO"
+    qECHO=$func_quote_arg_result
+    $ECHO "\
+
+# A function that is used when there is no print builtin or printf.
+func_fallback_echo ()
+{
+  eval 'cat <<_LTECHO_EOF
+\$1
+_LTECHO_EOF'
+}
+    ECHO=$qECHO
+  fi
+
+# Very basic option parsing. These options are (a) specific to
+# the libtool wrapper, (b) are identical between the wrapper
+# /script/ and the wrapper /executable/ that is used only on
+# windows platforms, and (c) all begin with the string "--lt-"
+# (application programs are unlikely to have options that match
+# this pattern).
+#
+# There are only two supported options: --lt-debug and
+# --lt-dump-script. There is, deliberately, no --lt-help.
+#
+# The first argument to this parsing function should be the
+# script's $0 value, followed by "$@".
+lt_option_debug=
+func_parse_lt_options ()
+{
+  lt_script_arg0=\$0
+  shift
+  for lt_opt
+  do
+    case \"\$lt_opt\" in
+    --lt-debug) lt_option_debug=1 ;;
+    --lt-dump-script)
+        lt_dump_D=\`\$ECHO \"X\$lt_script_arg0\" | $SED -e 's/^X//' -e 's%/[^/]*$%%'\`
+        test \"X\$lt_dump_D\" = \"X\$lt_script_arg0\" && lt_dump_D=.
+        lt_dump_F=\`\$ECHO \"X\$lt_script_arg0\" | $SED -e 's/^X//' -e 's%^.*/%%'\`
+        cat \"\$lt_dump_D/\$lt_dump_F\"
+        exit 0
+      ;;
+    --lt-*)
+        \$ECHO \"Unrecognized --lt- option: '\$lt_opt'\" 1>&2
+        exit 1
+      ;;
+    esac
+  done
+
+  # Print the debug banner immediately:
+  if test -n \"\$lt_option_debug\"; then
+    echo \"$outputname:$output:\$LINENO: libtool wrapper (GNU $PACKAGE) $VERSION\" 1>&2
+  fi
+}
+
+# Used when --lt-debug. Prints its arguments to stdout
+# (redirection is the responsibility of the caller)
+func_lt_dump_args ()
+{
+  lt_dump_args_N=1;
+  for lt_arg
+  do
+    \$ECHO \"$outputname:$output:\$LINENO: newargv[\$lt_dump_args_N]: \$lt_arg\"
+    lt_dump_args_N=\`expr \$lt_dump_args_N + 1\`
+  done
+}
+
+# Core function for launching the target application
+func_exec_program_core ()
+{
+"
+  case $host in
+  # Backslashes separate directories on plain windows
+  *-*-mingw | *-*-os2* | *-cegcc*)
+    $ECHO "\
+      if test -n \"\$lt_option_debug\"; then
+        \$ECHO \"$outputname:$output:\$LINENO: newargv[0]: \$progdir\\\\\$program\" 1>&2
+        func_lt_dump_args \${1+\"\$@\"} 1>&2
+      fi
+      exec \"\$progdir\\\\\$program\" \${1+\"\$@\"}
+"
+    ;;
+
+  *)
+    $ECHO "\
+      if test -n \"\$lt_option_debug\"; then
+        \$ECHO \"$outputname:$output:\$LINENO: newargv[0]: \$progdir/\$program\" 1>&2
+        func_lt_dump_args \${1+\"\$@\"} 1>&2
+      fi
+      exec \"\$progdir/\$program\" \${1+\"\$@\"}
+"
+    ;;
+  esac
+  $ECHO "\
+      \$ECHO \"\$0: cannot exec \$program \$*\" 1>&2
+      exit 1
+}
+
+# A function to encapsulate launching the target application
+# Strips options in the --lt-* namespace from \$@ and
+# launches target application with the remaining arguments.
+func_exec_program ()
+{
+  case \" \$* \" in
+  *\\ --lt-*)
+    for lt_wr_arg
+    do
+      case \$lt_wr_arg in
+      --lt-*) ;;
+      *) set x \"\$@\" \"\$lt_wr_arg\"; shift;;
+      esac
+      shift
+    done ;;
+  esac
+  func_exec_program_core \${1+\"\$@\"}
+}
+
+  # Parse options
+  func_parse_lt_options \"\$0\" \${1+\"\$@\"}
+
+  # Find the directory that this script lives in.
+  thisdir=\`\$ECHO \"\$file\" | $SED 's%/[^/]*$%%'\`
+  test \"x\$thisdir\" = \"x\$file\" && thisdir=.
+
+  # Follow symbolic links until we get to the real thisdir.
+  file=\`ls -ld \"\$file\" | $SED -n 's/.*-> //p'\`
+  while test -n \"\$file\"; do
+    destdir=\`\$ECHO \"\$file\" | $SED 's%/[^/]*\$%%'\`
+
+    # If there was a directory component, then change thisdir.
+    if test \"x\$destdir\" != \"x\$file\"; then
+      case \"\$destdir\" in
+      [\\\\/]* | [A-Za-z]:[\\\\/]*) thisdir=\"\$destdir\" ;;
+      *) thisdir=\"\$thisdir/\$destdir\" ;;
+      esac
+    fi
+
+    file=\`\$ECHO \"\$file\" | $SED 's%^.*/%%'\`
+    file=\`ls -ld \"\$thisdir/\$file\" | $SED -n 's/.*-> //p'\`
+  done
+
+  # Usually 'no', except on cygwin/mingw when embedded into
+  # the cwrapper.
+  WRAPPER_SCRIPT_BELONGS_IN_OBJDIR=$func_emit_wrapper_arg1
+  if test \"\$WRAPPER_SCRIPT_BELONGS_IN_OBJDIR\" = \"yes\"; then
+    # special case for '.'
+    if test \"\$thisdir\" = \".\"; then
+      thisdir=\`pwd\`
+    fi
+    # remove .libs from thisdir
+    case \"\$thisdir\" in
+    *[\\\\/]$objdir ) thisdir=\`\$ECHO \"\$thisdir\" | $SED 's%[\\\\/][^\\\\/]*$%%'\` ;;
+    $objdir )   thisdir=. ;;
+    esac
+  fi
+
+  # Try to get the absolute directory name.
+  absdir=\`cd \"\$thisdir\" && pwd\`
+  test -n \"\$absdir\" && thisdir=\"\$absdir\"
+"
+
+	if test yes = "$fast_install"; then
+	  $ECHO "\
+  program=lt-'$outputname'$exeext
+  progdir=\"\$thisdir/$objdir\"
+
+  if test ! -f \"\$progdir/\$program\" ||
+     { file=\`ls -1dt \"\$progdir/\$program\" \"\$progdir/../\$program\" 2>/dev/null | $SED 1q\`; \\
+       test \"X\$file\" != \"X\$progdir/\$program\"; }; then
+
+    file=\"\$\$-\$program\"
+
+    if test ! -d \"\$progdir\"; then
+      $MKDIR \"\$progdir\"
+    else
+      $RM \"\$progdir/\$file\"
+    fi"
+
+	  $ECHO "\
+
+    # relink executable if necessary
+    if test -n \"\$relink_command\"; then
+      if relink_command_output=\`eval \$relink_command 2>&1\`; then :
+      else
+	\$ECHO \"\$relink_command_output\" >&2
+	$RM \"\$progdir/\$file\"
+	exit 1
+      fi
+    fi
+
+    $MV \"\$progdir/\$file\" \"\$progdir/\$program\" 2>/dev/null ||
+    { $RM \"\$progdir/\$program\";
+      $MV \"\$progdir/\$file\" \"\$progdir/\$program\"; }
+    $RM \"\$progdir/\$file\"
+  fi"
+	else
+	  $ECHO "\
+  program='$outputname'
+  progdir=\"\$thisdir/$objdir\"
+"
+	fi
+
+	$ECHO "\
+
+  if test -f \"\$progdir/\$program\"; then"
+
+	# fixup the dll searchpath if we need to.
+	#
+	# Fix the DLL searchpath if we need to.  Do this before prepending
+	# to shlibpath, because on Windows, both are PATH and uninstalled
+	# libraries must come first.
+	if test -n "$dllsearchpath"; then
+	  $ECHO "\
+    # Add the dll search path components to the executable PATH
+    PATH=$dllsearchpath:\$PATH
+"
+	fi
+
+	# Export our shlibpath_var if we have one.
+	if test yes = "$shlibpath_overrides_runpath" && test -n "$shlibpath_var" && test -n "$temp_rpath"; then
+	  $ECHO "\
+    # Add our own library path to $shlibpath_var
+    $shlibpath_var=\"$temp_rpath\$$shlibpath_var\"
+
+    # Some systems cannot cope with colon-terminated $shlibpath_var
+    # The second colon is a workaround for a bug in BeOS R4 sed
+    $shlibpath_var=\`\$ECHO \"\$$shlibpath_var\" | $SED 's/::*\$//'\`
+
+    export $shlibpath_var
+"
+	fi
+
+	$ECHO "\
+    if test \"\$libtool_execute_magic\" != \"$magic\"; then
+      # Run the actual program with our arguments.
+      func_exec_program \${1+\"\$@\"}
+    fi
+  else
+    # The program doesn't exist.
+    \$ECHO \"\$0: error: '\$progdir/\$program' does not exist\" 1>&2
+    \$ECHO \"This script is just a wrapper for \$program.\" 1>&2
+    \$ECHO \"See the $PACKAGE documentation for more information.\" 1>&2
+    exit 1
+  fi
+fi\
+"
+}
+
+
+# func_emit_cwrapperexe_src
+# emit the source code for a wrapper executable on stdout
+# Must ONLY be called from within func_mode_link because
+# it depends on a number of variable set therein.
+func_emit_cwrapperexe_src ()
+{
+	cat <<EOF
+
+/* $cwrappersource - temporary wrapper executable for $objdir/$outputname
+   Generated by $PROGRAM (GNU $PACKAGE) $VERSION
+
+   The $output program cannot be directly executed until all the libtool
+   libraries that it depends on are installed.
+
+   This wrapper executable should never be moved out of the build directory.
+   If it is, it will not operate correctly.
+*/
+EOF
+	    cat <<"EOF"
+#ifdef _MSC_VER
+# define _CRT_SECURE_NO_DEPRECATE 1
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef _MSC_VER
+# include <direct.h>
+# include <process.h>
+# include <io.h>
+#else
+# include <unistd.h>
+# include <stdint.h>
+# ifdef __CYGWIN__
+#  include <io.h>
+# endif
+#endif
+#include <malloc.h>
+#include <stdarg.h>
+#include <assert.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+
+#define STREQ(s1, s2) (strcmp ((s1), (s2)) == 0)
+
+/* declarations of non-ANSI functions */
+#if defined __MINGW32__
+# ifdef __STRICT_ANSI__
+int _putenv (const char *);
+# endif
+#elif defined __CYGWIN__
+# ifdef __STRICT_ANSI__
+char *realpath (const char *, char *);
+int putenv (char *);
+int setenv (const char *, const char *, int);
+# endif
+/* #elif defined other_platform || defined ... */
+#endif
+
+/* portability defines, excluding path handling macros */
+#if defined _MSC_VER
+# define setmode _setmode
+# define stat    _stat
+# define chmod   _chmod
+# define getcwd  _getcwd
+# define putenv  _putenv
+# define S_IXUSR _S_IEXEC
+#elif defined __MINGW32__
+# define setmode _setmode
+# define stat    _stat
+# define chmod   _chmod
+# define getcwd  _getcwd
+# define putenv  _putenv
+#elif defined __CYGWIN__
+# define HAVE_SETENV
+# define FOPEN_WB "wb"
+/* #elif defined other platforms ... */
+#endif
+
+#if defined PATH_MAX
+# define LT_PATHMAX PATH_MAX
+#elif defined MAXPATHLEN
+# define LT_PATHMAX MAXPATHLEN
+#else
+# define LT_PATHMAX 1024
+#endif
+
+#ifndef S_IXOTH
+# define S_IXOTH 0
+#endif
+#ifndef S_IXGRP
+# define S_IXGRP 0
+#endif
+
+/* path handling portability macros */
+#ifndef DIR_SEPARATOR
+# define DIR_SEPARATOR '/'
+# define PATH_SEPARATOR ':'
+#endif
+
+#if defined _WIN32 || defined __MSDOS__ || defined __DJGPP__ || \
+  defined __OS2__
+# define HAVE_DOS_BASED_FILE_SYSTEM
+# define FOPEN_WB "wb"
+# ifndef DIR_SEPARATOR_2
+#  define DIR_SEPARATOR_2 '\\'
+# endif
+# ifndef PATH_SEPARATOR_2
+#  define PATH_SEPARATOR_2 ';'
+# endif
+#endif
+
+#ifndef DIR_SEPARATOR_2
+# define IS_DIR_SEPARATOR(ch) ((ch) == DIR_SEPARATOR)
+#else /* DIR_SEPARATOR_2 */
+# define IS_DIR_SEPARATOR(ch) \
+	(((ch) == DIR_SEPARATOR) || ((ch) == DIR_SEPARATOR_2))
+#endif /* DIR_SEPARATOR_2 */
+
+#ifndef PATH_SEPARATOR_2
+# define IS_PATH_SEPARATOR(ch) ((ch) == PATH_SEPARATOR)
+#else /* PATH_SEPARATOR_2 */
+# define IS_PATH_SEPARATOR(ch) ((ch) == PATH_SEPARATOR_2)
+#endif /* PATH_SEPARATOR_2 */
+
+#ifndef FOPEN_WB
+# define FOPEN_WB "w"
+#endif
+#ifndef _O_BINARY
+# define _O_BINARY 0
+#endif
+
+#define XMALLOC(type, num)      ((type *) xmalloc ((num) * sizeof(type)))
+#define XFREE(stale) do { \
+  if (stale) { free (stale); stale = 0; } \
+} while (0)
+
+#if defined LT_DEBUGWRAPPER
+static int lt_debug = 1;
+#else
+static int lt_debug = 0;
+#endif
+
+const char *program_name = "libtool-wrapper"; /* in case xstrdup fails */
+
+void *xmalloc (size_t num);
+char *xstrdup (const char *string);
+const char *base_name (const char *name);
+char *find_executable (const char *wrapper);
+char *chase_symlinks (const char *pathspec);
+int make_executable (const char *path);
+int check_executable (const char *path);
+char *strendzap (char *str, const char *pat);
+void lt_debugprintf (const char *file, int line, const char *fmt, ...);
+void lt_fatal (const char *file, int line, const char *message, ...);
+static const char *nonnull (const char *s);
+static const char *nonempty (const char *s);
+void lt_setenv (const char *name, const char *value);
+char *lt_extend_str (const char *orig_value, const char *add, int to_end);
+void lt_update_exe_path (const char *name, const char *value);
+void lt_update_lib_path (const char *name, const char *value);
+char **prepare_spawn (char **argv);
+void lt_dump_script (FILE *f);
+EOF
+
+	    cat <<EOF
+#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 5)
+# define externally_visible volatile
+#else
+# define externally_visible __attribute__((externally_visible)) volatile
+#endif
+externally_visible const char * MAGIC_EXE = "$magic_exe";
+const char * LIB_PATH_VARNAME = "$shlibpath_var";
+EOF
+
+	    if test yes = "$shlibpath_overrides_runpath" && test -n "$shlibpath_var" && test -n "$temp_rpath"; then
+              func_to_host_path "$temp_rpath"
+	      cat <<EOF
+const char * LIB_PATH_VALUE   = "$func_to_host_path_result";
+EOF
+	    else
+	      cat <<"EOF"
+const char * LIB_PATH_VALUE   = "";
+EOF
+	    fi
+
+	    if test -n "$dllsearchpath"; then
+              func_to_host_path "$dllsearchpath:"
+	      cat <<EOF
+const char * EXE_PATH_VARNAME = "PATH";
+const char * EXE_PATH_VALUE   = "$func_to_host_path_result";
+EOF
+	    else
+	      cat <<"EOF"
+const char * EXE_PATH_VARNAME = "";
+const char * EXE_PATH_VALUE   = "";
+EOF
+	    fi
+
+	    if test yes = "$fast_install"; then
+	      cat <<EOF
+const char * TARGET_PROGRAM_NAME = "lt-$outputname"; /* hopefully, no .exe */
+EOF
+	    else
+	      cat <<EOF
+const char * TARGET_PROGRAM_NAME = "$outputname"; /* hopefully, no .exe */
+EOF
+	    fi
+
+
+	    cat <<"EOF"
+
+#define LTWRAPPER_OPTION_PREFIX         "--lt-"
+
+static const char *ltwrapper_option_prefix = LTWRAPPER_OPTION_PREFIX;
+static const char *dumpscript_opt       = LTWRAPPER_OPTION_PREFIX "dump-script";
+static const char *debug_opt            = LTWRAPPER_OPTION_PREFIX "debug";
+
+int
+main (int argc, char *argv[])
+{
+  char **newargz;
+  int  newargc;
+  char *tmp_pathspec;
+  char *actual_cwrapper_path;
+  char *actual_cwrapper_name;
+  char *target_name;
+  char *lt_argv_zero;
+  int rval = 127;
+
+  int i;
+
+  program_name = (char *) xstrdup (base_name (argv[0]));
+  newargz = XMALLOC (char *, (size_t) argc + 1);
+
+  /* very simple arg parsing; don't want to rely on getopt
+   * also, copy all non cwrapper options to newargz, except
+   * argz[0], which is handled differently
+   */
+  newargc=0;
+  for (i = 1; i < argc; i++)
+    {
+      if (STREQ (argv[i], dumpscript_opt))
+	{
+EOF
+	    case $host in
+	      *mingw* | *cygwin* )
+		# make stdout use "unix" line endings
+		echo "          setmode(1,_O_BINARY);"
+		;;
+	      esac
+
+	    cat <<"EOF"
+	  lt_dump_script (stdout);
+	  return 0;
+	}
+      if (STREQ (argv[i], debug_opt))
+	{
+          lt_debug = 1;
+          continue;
+	}
+      if (STREQ (argv[i], ltwrapper_option_prefix))
+        {
+          /* however, if there is an option in the LTWRAPPER_OPTION_PREFIX
+             namespace, but it is not one of the ones we know about and
+             have already dealt with, above (inluding dump-script), then
+             report an error. Otherwise, targets might begin to believe
+             they are allowed to use options in the LTWRAPPER_OPTION_PREFIX
+             namespace. The first time any user complains about this, we'll
+             need to make LTWRAPPER_OPTION_PREFIX a configure-time option
+             or a configure.ac-settable value.
+           */
+          lt_fatal (__FILE__, __LINE__,
+		    "unrecognized %s option: '%s'",
+                    ltwrapper_option_prefix, argv[i]);
+        }
+      /* otherwise ... */
+      newargz[++newargc] = xstrdup (argv[i]);
+    }
+  newargz[++newargc] = NULL;
+
+EOF
+	    cat <<EOF
+  /* The GNU banner must be the first non-error debug message */
+  lt_debugprintf (__FILE__, __LINE__, "libtool wrapper (GNU $PACKAGE) $VERSION\n");
+EOF
+	    cat <<"EOF"
+  lt_debugprintf (__FILE__, __LINE__, "(main) argv[0]: %s\n", argv[0]);
+  lt_debugprintf (__FILE__, __LINE__, "(main) program_name: %s\n", program_name);
+
+  tmp_pathspec = find_executable (argv[0]);
+  if (tmp_pathspec == NULL)
+    lt_fatal (__FILE__, __LINE__, "couldn't find %s", argv[0]);
+  lt_debugprintf (__FILE__, __LINE__,
+                  "(main) found exe (before symlink chase) at: %s\n",
+		  tmp_pathspec);
+
+  actual_cwrapper_path = chase_symlinks (tmp_pathspec);
+  lt_debugprintf (__FILE__, __LINE__,
+                  "(main) found exe (after symlink chase) at: %s\n",
+		  actual_cwrapper_path);
+  XFREE (tmp_pathspec);
+
+  actual_cwrapper_name = xstrdup (base_name (actual_cwrapper_path));
+  strendzap (actual_cwrapper_path, actual_cwrapper_name);
+
+  /* wrapper name transforms */
+  strendzap (actual_cwrapper_name, ".exe");
+  tmp_pathspec = lt_extend_str (actual_cwrapper_name, ".exe", 1);
+  XFREE (actual_cwrapper_name);
+  actual_cwrapper_name = tmp_pathspec;
+  tmp_pathspec = 0;
+
+  /* target_name transforms -- use actual target program name; might have lt- prefix */
+  target_name = xstrdup (base_name (TARGET_PROGRAM_NAME));
+  strendzap (target_name, ".exe");
+  tmp_pathspec = lt_extend_str (target_name, ".exe", 1);
+  XFREE (target_name);
+  target_name = tmp_pathspec;
+  tmp_pathspec = 0;
+
+  lt_debugprintf (__FILE__, __LINE__,
+		  "(main) libtool target name: %s\n",
+		  target_name);
+EOF
+
+	    cat <<EOF
+  newargz[0] =
+    XMALLOC (char, (strlen (actual_cwrapper_path) +
+		    strlen ("$objdir") + 1 + strlen (actual_cwrapper_name) + 1));
+  strcpy (newargz[0], actual_cwrapper_path);
+  strcat (newargz[0], "$objdir");
+  strcat (newargz[0], "/");
+EOF
+
+	    cat <<"EOF"
+  /* stop here, and copy so we don't have to do this twice */
+  tmp_pathspec = xstrdup (newargz[0]);
+
+  /* do NOT want the lt- prefix here, so use actual_cwrapper_name */
+  strcat (newargz[0], actual_cwrapper_name);
+
+  /* DO want the lt- prefix here if it exists, so use target_name */
+  lt_argv_zero = lt_extend_str (tmp_pathspec, target_name, 1);
+  XFREE (tmp_pathspec);
+  tmp_pathspec = NULL;
+EOF
+
+	    case $host_os in
+	      mingw*)
+	    cat <<"EOF"
+  {
+    char* p;
+    while ((p = strchr (newargz[0], '\\')) != NULL)
+      {
+	*p = '/';
+      }
+    while ((p = strchr (lt_argv_zero, '\\')) != NULL)
+      {
+	*p = '/';
+      }
+  }
+EOF
+	    ;;
+	    esac
+
+	    cat <<"EOF"
+  XFREE (target_name);
+  XFREE (actual_cwrapper_path);
+  XFREE (actual_cwrapper_name);
+
+  lt_setenv ("BIN_SH", "xpg4"); /* for Tru64 */
+  lt_setenv ("DUALCASE", "1");  /* for MSK sh */
+  /* Update the DLL searchpath.  EXE_PATH_VALUE ($dllsearchpath) must
+     be prepended before (that is, appear after) LIB_PATH_VALUE ($temp_rpath)
+     because on Windows, both *_VARNAMEs are PATH but uninstalled
+     libraries must come first. */
+  lt_update_exe_path (EXE_PATH_VARNAME, EXE_PATH_VALUE);
+  lt_update_lib_path (LIB_PATH_VARNAME, LIB_PATH_VALUE);
+
+  lt_debugprintf (__FILE__, __LINE__, "(main) lt_argv_zero: %s\n",
+		  nonnull (lt_argv_zero));
+  for (i = 0; i < newargc; i++)
+    {
+      lt_debugprintf (__FILE__, __LINE__, "(main) newargz[%d]: %s\n",
+		      i, nonnull (newargz[i]));
+    }
+
+EOF
+
+	    case $host_os in
+	      mingw*)
+		cat <<"EOF"
+  /* execv doesn't actually work on mingw as expected on unix */
+  newargz = prepare_spawn (newargz);
+  rval = (int) _spawnv (_P_WAIT, lt_argv_zero, (const char * const *) newargz);
+  if (rval == -1)
+    {
+      /* failed to start process */
+      lt_debugprintf (__FILE__, __LINE__,
+		      "(main) failed to launch target \"%s\": %s\n",
+		      lt_argv_zero, nonnull (strerror (errno)));
+      return 127;
+    }
+  return rval;
+EOF
+		;;
+	      *)
+		cat <<"EOF"
+  execv (lt_argv_zero, newargz);
+  return rval; /* =127, but avoids unused variable warning */
+EOF
+		;;
+	    esac
+
+	    cat <<"EOF"
+}
+
+void *
+xmalloc (size_t num)
+{
+  void *p = (void *) malloc (num);
+  if (!p)
+    lt_fatal (__FILE__, __LINE__, "memory exhausted");
+
+  return p;
+}
+
+char *
+xstrdup (const char *string)
+{
+  return string ? strcpy ((char *) xmalloc (strlen (string) + 1),
+			  string) : NULL;
+}
+
+const char *
+base_name (const char *name)
+{
+  const char *base;
+
+#if defined HAVE_DOS_BASED_FILE_SYSTEM
+  /* Skip over the disk name in MSDOS pathnames. */
+  if (isalpha ((unsigned char) name[0]) && name[1] == ':')
+    name += 2;
+#endif
+
+  for (base = name; *name; name++)
+    if (IS_DIR_SEPARATOR (*name))
+      base = name + 1;
+  return base;
+}
+
+int
+check_executable (const char *path)
+{
+  struct stat st;
+
+  lt_debugprintf (__FILE__, __LINE__, "(check_executable): %s\n",
+                  nonempty (path));
+  if ((!path) || (!*path))
+    return 0;
+
+  if ((stat (path, &st) >= 0)
+      && (st.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)))
+    return 1;
+  else
+    return 0;
+}
+
+int
+make_executable (const char *path)
+{
+  int rval = 0;
+  struct stat st;
+
+  lt_debugprintf (__FILE__, __LINE__, "(make_executable): %s\n",
+                  nonempty (path));
+  if ((!path) || (!*path))
+    return 0;
+
+  if (stat (path, &st) >= 0)
+    {
+      rval = chmod (path, st.st_mode | S_IXOTH | S_IXGRP | S_IXUSR);
+    }
+  return rval;
+}
+
+/* Searches for the full path of the wrapper.  Returns
+   newly allocated full path name if found, NULL otherwise
+   Does not chase symlinks, even on platforms that support them.
+*/
+char *
+find_executable (const char *wrapper)
+{
+  int has_slash = 0;
+  const char *p;
+  const char *p_next;
+  /* static buffer for getcwd */
+  char tmp[LT_PATHMAX + 1];
+  size_t tmp_len;
+  char *concat_name;
+
+  lt_debugprintf (__FILE__, __LINE__, "(find_executable): %s\n",
+                  nonempty (wrapper));
+
+  if ((wrapper == NULL) || (*wrapper == '\0'))
+    return NULL;
+
+  /* Absolute path? */
+#if defined HAVE_DOS_BASED_FILE_SYSTEM
+  if (isalpha ((unsigned char) wrapper[0]) && wrapper[1] == ':')
+    {
+      concat_name = xstrdup (wrapper);
+      if (check_executable (concat_name))
+	return concat_name;
+      XFREE (concat_name);
+    }
+  else
+    {
+#endif
+      if (IS_DIR_SEPARATOR (wrapper[0]))
+	{
+	  concat_name = xstrdup (wrapper);
+	  if (check_executable (concat_name))
+	    return concat_name;
+	  XFREE (concat_name);
+	}
+#if defined HAVE_DOS_BASED_FILE_SYSTEM
+    }
+#endif
+
+  for (p = wrapper; *p; p++)
+    if (*p == '/')
+      {
+	has_slash = 1;
+	break;
+      }
+  if (!has_slash)
+    {
+      /* no slashes; search PATH */
+      const char *path = getenv ("PATH");
+      if (path != NULL)
+	{
+	  for (p = path; *p; p = p_next)
+	    {
+	      const char *q;
+	      size_t p_len;
+	      for (q = p; *q; q++)
+		if (IS_PATH_SEPARATOR (*q))
+		  break;
+	      p_len = (size_t) (q - p);
+	      p_next = (*q == '\0' ? q : q + 1);
+	      if (p_len == 0)
+		{
+		  /* empty path: current directory */
+		  if (getcwd (tmp, LT_PATHMAX) == NULL)
+		    lt_fatal (__FILE__, __LINE__, "getcwd failed: %s",
+                              nonnull (strerror (errno)));
+		  tmp_len = strlen (tmp);
+		  concat_name =
+		    XMALLOC (char, tmp_len + 1 + strlen (wrapper) + 1);
+		  memcpy (concat_name, tmp, tmp_len);
+		  concat_name[tmp_len] = '/';
+		  strcpy (concat_name + tmp_len + 1, wrapper);
+		}
+	      else
+		{
+		  concat_name =
+		    XMALLOC (char, p_len + 1 + strlen (wrapper) + 1);
+		  memcpy (concat_name, p, p_len);
+		  concat_name[p_len] = '/';
+		  strcpy (concat_name + p_len + 1, wrapper);
+		}
+	      if (check_executable (concat_name))
+		return concat_name;
+	      XFREE (concat_name);
+	    }
+	}
+      /* not found in PATH; assume curdir */
+    }
+  /* Relative path | not found in path: prepend cwd */
+  if (getcwd (tmp, LT_PATHMAX) == NULL)
+    lt_fatal (__FILE__, __LINE__, "getcwd failed: %s",
+              nonnull (strerror (errno)));
+  tmp_len = strlen (tmp);
+  concat_name = XMALLOC (char, tmp_len + 1 + strlen (wrapper) + 1);
+  memcpy (concat_name, tmp, tmp_len);
+  concat_name[tmp_len] = '/';
+  strcpy (concat_name + tmp_len + 1, wrapper);
+
+  if (check_executable (concat_name))
+    return concat_name;
+  XFREE (concat_name);
+  return NULL;
+}
+
+char *
+chase_symlinks (const char *pathspec)
+{
+#ifndef S_ISLNK
+  return xstrdup (pathspec);
+#else
+  char buf[LT_PATHMAX];
+  struct stat s;
+  char *tmp_pathspec = xstrdup (pathspec);
+  char *p;
+  int has_symlinks = 0;
+  while (strlen (tmp_pathspec) && !has_symlinks)
+    {
+      lt_debugprintf (__FILE__, __LINE__,
+		      "checking path component for symlinks: %s\n",
+		      tmp_pathspec);
+      if (lstat (tmp_pathspec, &s) == 0)
+	{
+	  if (S_ISLNK (s.st_mode) != 0)
+	    {
+	      has_symlinks = 1;
+	      break;
+	    }
+
+	  /* search backwards for last DIR_SEPARATOR */
+	  p = tmp_pathspec + strlen (tmp_pathspec) - 1;
+	  while ((p > tmp_pathspec) && (!IS_DIR_SEPARATOR (*p)))
+	    p--;
+	  if ((p == tmp_pathspec) && (!IS_DIR_SEPARATOR (*p)))
+	    {
+	      /* no more DIR_SEPARATORS left */
+	      break;
+	    }
+	  *p = '\0';
+	}
+      else
+	{
+	  lt_fatal (__FILE__, __LINE__,
+		    "error accessing file \"%s\": %s",
+		    tmp_pathspec, nonnull (strerror (errno)));
+	}
+    }
+  XFREE (tmp_pathspec);
+
+  if (!has_symlinks)
+    {
+      return xstrdup (pathspec);
+    }
+
+  tmp_pathspec = realpath (pathspec, buf);
+  if (tmp_pathspec == 0)
+    {
+      lt_fatal (__FILE__, __LINE__,
+		"could not follow symlinks for %s", pathspec);
+    }
+  return xstrdup (tmp_pathspec);
+#endif
+}
+
+char *
+strendzap (char *str, const char *pat)
+{
+  size_t len, patlen;
+
+  assert (str != NULL);
+  assert (pat != NULL);
+
+  len = strlen (str);
+  patlen = strlen (pat);
+
+  if (patlen <= len)
+    {
+      str += len - patlen;
+      if (STREQ (str, pat))
+	*str = '\0';
+    }
+  return str;
+}
+
+void
+lt_debugprintf (const char *file, int line, const char *fmt, ...)
+{
+  va_list args;
+  if (lt_debug)
+    {
+      (void) fprintf (stderr, "%s:%s:%d: ", program_name, file, line);
+      va_start (args, fmt);
+      (void) vfprintf (stderr, fmt, args);
+      va_end (args);
+    }
+}
+
+static void
+lt_error_core (int exit_status, const char *file,
+	       int line, const char *mode,
+	       const char *message, va_list ap)
+{
+  fprintf (stderr, "%s:%s:%d: %s: ", program_name, file, line, mode);
+  vfprintf (stderr, message, ap);
+  fprintf (stderr, ".\n");
+
+  if (exit_status >= 0)
+    exit (exit_status);
+}
+
+void
+lt_fatal (const char *file, int line, const char *message, ...)
+{
+  va_list ap;
+  va_start (ap, message);
+  lt_error_core (EXIT_FAILURE, file, line, "FATAL", message, ap);
+  va_end (ap);
+}
+
+static const char *
+nonnull (const char *s)
+{
+  return s ? s : "(null)";
+}
+
+static const char *
+nonempty (const char *s)
+{
+  return (s && !*s) ? "(empty)" : nonnull (s);
+}
+
+void
+lt_setenv (const char *name, const char *value)
+{
+  lt_debugprintf (__FILE__, __LINE__,
+		  "(lt_setenv) setting '%s' to '%s'\n",
+                  nonnull (name), nonnull (value));
+  {
+#ifdef HAVE_SETENV
+    /* always make a copy, for consistency with !HAVE_SETENV */
+    char *str = xstrdup (value);
+    setenv (name, str, 1);
+#else
+    size_t len = strlen (name) + 1 + strlen (value) + 1;
+    char *str = XMALLOC (char, len);
+    sprintf (str, "%s=%s", name, value);
+    if (putenv (str) != EXIT_SUCCESS)
+      {
+        XFREE (str);
+      }
+#endif
+  }
+}
+
+char *
+lt_extend_str (const char *orig_value, const char *add, int to_end)
+{
+  char *new_value;
+  if (orig_value && *orig_value)
+    {
+      size_t orig_value_len = strlen (orig_value);
+      size_t add_len = strlen (add);
+      new_value = XMALLOC (char, add_len + orig_value_len + 1);
+      if (to_end)
+        {
+          strcpy (new_value, orig_value);
+          strcpy (new_value + orig_value_len, add);
+        }
+      else
+        {
+          strcpy (new_value, add);
+          strcpy (new_value + add_len, orig_value);
+        }
+    }
+  else
+    {
+      new_value = xstrdup (add);
+    }
+  return new_value;
+}
+
+void
+lt_update_exe_path (const char *name, const char *value)
+{
+  lt_debugprintf (__FILE__, __LINE__,
+		  "(lt_update_exe_path) modifying '%s' by prepending '%s'\n",
+                  nonnull (name), nonnull (value));
+
+  if (name && *name && value && *value)
+    {
+      char *new_value = lt_extend_str (getenv (name), value, 0);
+      /* some systems can't cope with a ':'-terminated path #' */
+      size_t len = strlen (new_value);
+      while ((len > 0) && IS_PATH_SEPARATOR (new_value[len-1]))
+        {
+          new_value[--len] = '\0';
+        }
+      lt_setenv (name, new_value);
+      XFREE (new_value);
+    }
+}
+
+void
+lt_update_lib_path (const char *name, const char *value)
+{
+  lt_debugprintf (__FILE__, __LINE__,
+		  "(lt_update_lib_path) modifying '%s' by prepending '%s'\n",
+                  nonnull (name), nonnull (value));
+
+  if (name && *name && value && *value)
+    {
+      char *new_value = lt_extend_str (getenv (name), value, 0);
+      lt_setenv (name, new_value);
+      XFREE (new_value);
+    }
+}
+
+EOF
+	    case $host_os in
+	      mingw*)
+		cat <<"EOF"
+
+/* Prepares an argument vector before calling spawn().
+   Note that spawn() does not by itself call the command interpreter
+     (getenv ("COMSPEC") != NULL ? getenv ("COMSPEC") :
+      ({ OSVERSIONINFO v; v.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
+         GetVersionEx(&v);
+         v.dwPlatformId == VER_PLATFORM_WIN32_NT;
+      }) ? "cmd.exe" : "command.com").
+   Instead it simply concatenates the arguments, separated by ' ', and calls
+   CreateProcess().  We must quote the arguments since Win32 CreateProcess()
+   interprets characters like ' ', '\t', '\\', '"' (but not '<' and '>') in a
+   special way:
+   - Space and tab are interpreted as delimiters. They are not treated as
+     delimiters if they are surrounded by double quotes: "...".
+   - Unescaped double quotes are removed from the input. Their only effect is
+     that within double quotes, space and tab are treated like normal
+     characters.
+   - Backslashes not followed by double quotes are not special.
+   - But 2*n+1 backslashes followed by a double quote become
+     n backslashes followed by a double quote (n >= 0):
+       \" -> "
+       \\\" -> \"
+       \\\\\" -> \\"
+ */
+#define SHELL_SPECIAL_CHARS "\"\\ \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037"
+#define SHELL_SPACE_CHARS " \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037"
+char **
+prepare_spawn (char **argv)
+{
+  size_t argc;
+  char **new_argv;
+  size_t i;
+
+  /* Count number of arguments.  */
+  for (argc = 0; argv[argc] != NULL; argc++)
+    ;
+
+  /* Allocate new argument vector.  */
+  new_argv = XMALLOC (char *, argc + 1);
+
+  /* Put quoted arguments into the new argument vector.  */
+  for (i = 0; i < argc; i++)
+    {
+      const char *string = argv[i];
+
+      if (string[0] == '\0')
+	new_argv[i] = xstrdup ("\"\"");
+      else if (strpbrk (string, SHELL_SPECIAL_CHARS) != NULL)
+	{
+	  int quote_around = (strpbrk (string, SHELL_SPACE_CHARS) != NULL);
+	  size_t length;
+	  unsigned int backslashes;
+	  const char *s;
+	  char *quoted_string;
+	  char *p;
+
+	  length = 0;
+	  backslashes = 0;
+	  if (quote_around)
+	    length++;
+	  for (s = string; *s != '\0'; s++)
+	    {
+	      char c = *s;
+	      if (c == '"')
+		length += backslashes + 1;
+	      length++;
+	      if (c == '\\')
+		backslashes++;
+	      else
+		backslashes = 0;
+	    }
+	  if (quote_around)
+	    length += backslashes + 1;
+
+	  quoted_string = XMALLOC (char, length + 1);
+
+	  p = quoted_string;
+	  backslashes = 0;
+	  if (quote_around)
+	    *p++ = '"';
+	  for (s = string; *s != '\0'; s++)
+	    {
+	      char c = *s;
+	      if (c == '"')
+		{
+		  unsigned int j;
+		  for (j = backslashes + 1; j > 0; j--)
+		    *p++ = '\\';
+		}
+	      *p++ = c;
+	      if (c == '\\')
+		backslashes++;
+	      else
+		backslashes = 0;
+	    }
+	  if (quote_around)
+	    {
+	      unsigned int j;
+	      for (j = backslashes; j > 0; j--)
+		*p++ = '\\';
+	      *p++ = '"';
+	    }
+	  *p = '\0';
+
+	  new_argv[i] = quoted_string;
+	}
+      else
+	new_argv[i] = (char *) string;
+    }
+  new_argv[argc] = NULL;
+
+  return new_argv;
+}
+EOF
+		;;
+	    esac
+
+            cat <<"EOF"
+void lt_dump_script (FILE* f)
+{
+EOF
+	    func_emit_wrapper yes |
+	      $SED -n -e '
+s/^\(.\{79\}\)\(..*\)/\1\
+\2/
+h
+s/\([\\"]\)/\\\1/g
+s/$/\\n/
+s/\([^\n]*\).*/  fputs ("\1", f);/p
+g
+D'
+            cat <<"EOF"
+}
+EOF
+}
+# end: func_emit_cwrapperexe_src
+
+# func_win32_import_lib_p ARG
+# True if ARG is an import lib, as indicated by $file_magic_cmd
+func_win32_import_lib_p ()
+{
+    $debug_cmd
+
+    case `eval $file_magic_cmd \"\$1\" 2>/dev/null | $SED -e 10q` in
+    *import*) : ;;
+    *) false ;;
+    esac
+}
+
+# func_suncc_cstd_abi
+# !!ONLY CALL THIS FOR SUN CC AFTER $compile_command IS FULLY EXPANDED!!
+# Several compiler flags select an ABI that is incompatible with the
+# Cstd library. Avoid specifying it if any are in CXXFLAGS.
+func_suncc_cstd_abi ()
+{
+    $debug_cmd
+
+    case " $compile_command " in
+    *" -compat=g "*|*\ -std=c++[0-9][0-9]\ *|*" -library=stdcxx4 "*|*" -library=stlport4 "*)
+      suncc_use_cstd_abi=no
+      ;;
+    *)
+      suncc_use_cstd_abi=yes
+      ;;
+    esac
+}
+
+# func_mode_link arg...
+func_mode_link ()
+{
+    $debug_cmd
+
+    case $host in
+    *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
+      # It is impossible to link a dll without this setting, and
+      # we shouldn't force the makefile maintainer to figure out
+      # what system we are compiling for in order to pass an extra
+      # flag for every libtool invocation.
+      # allow_undefined=no
+
+      # FIXME: Unfortunately, there are problems with the above when trying
+      # to make a dll that has undefined symbols, in which case not
+      # even a static library is built.  For now, we need to specify
+      # -no-undefined on the libtool link line when we can be certain
+      # that all symbols are satisfied, otherwise we get a static library.
+      allow_undefined=yes
+      ;;
+    *)
+      allow_undefined=yes
+      ;;
+    esac
+    libtool_args=$nonopt
+    base_compile="$nonopt $@"
+    compile_command=$nonopt
+    finalize_command=$nonopt
+
+    compile_rpath=
+    finalize_rpath=
+    compile_shlibpath=
+    finalize_shlibpath=
+    convenience=
+    old_convenience=
+    deplibs=
+    old_deplibs=
+    compiler_flags=
+    linker_flags=
+    dllsearchpath=
+    lib_search_path=`pwd`
+    inst_prefix_dir=
+    new_inherited_linker_flags=
+
+    avoid_version=no
+    bindir=
+    dlfiles=
+    dlprefiles=
+    dlself=no
+    export_dynamic=no
+    export_symbols=
+    export_symbols_regex=
+    generated=
+    libobjs=
+    ltlibs=
+    module=no
+    no_install=no
+    objs=
+    os2dllname=
+    non_pic_objects=
+    precious_files_regex=
+    prefer_static_libs=no
+    preload=false
+    prev=
+    prevarg=
+    release=
+    rpath=
+    xrpath=
+    perm_rpath=
+    temp_rpath=
+    thread_safe=no
+    vinfo=
+    vinfo_number=no
+    weak_libs=
+    single_module=$wl-single_module
+    func_infer_tag $base_compile
+
+    # We need to know -static, to get the right output filenames.
+    for arg
+    do
+      case $arg in
+      -shared)
+	test yes != "$build_libtool_libs" \
+	  && func_fatal_configuration "cannot build a shared library"
+	build_old_libs=no
+	break
+	;;
+      -all-static | -static | -static-libtool-libs)
+	case $arg in
+	-all-static)
+	  if test yes = "$build_libtool_libs" && test -z "$link_static_flag"; then
+	    func_warning "complete static linking is impossible in this configuration"
+	  fi
+	  if test -n "$link_static_flag"; then
+	    dlopen_self=$dlopen_self_static
+	  fi
+	  prefer_static_libs=yes
+	  ;;
+	-static)
+	  if test -z "$pic_flag" && test -n "$link_static_flag"; then
+	    dlopen_self=$dlopen_self_static
+	  fi
+	  prefer_static_libs=built
+	  ;;
+	-static-libtool-libs)
+	  if test -z "$pic_flag" && test -n "$link_static_flag"; then
+	    dlopen_self=$dlopen_self_static
+	  fi
+	  prefer_static_libs=yes
+	  ;;
+	esac
+	build_libtool_libs=no
+	build_old_libs=yes
+	break
+	;;
+      esac
+    done
+
+    # See if our shared archives depend on static archives.
+    test -n "$old_archive_from_new_cmds" && build_old_libs=yes
+
+    # Go through the arguments, transforming them on the way.
+    while test "$#" -gt 0; do
+      arg=$1
+      shift
+      func_quote_arg pretty,unquoted "$arg"
+      qarg=$func_quote_arg_unquoted_result
+      func_append libtool_args " $func_quote_arg_result"
+
+      # If the previous option needs an argument, assign it.
+      if test -n "$prev"; then
+	case $prev in
+	output)
+	  func_append compile_command " @OUTPUT@"
+	  func_append finalize_command " @OUTPUT@"
+	  ;;
+	esac
+
+	case $prev in
+	bindir)
+	  bindir=$arg
+	  prev=
+	  continue
+	  ;;
+	dlfiles|dlprefiles)
+	  $preload || {
+	    # Add the symbol object into the linking commands.
+	    func_append compile_command " @SYMFILE@"
+	    func_append finalize_command " @SYMFILE@"
+	    preload=:
+	  }
+	  case $arg in
+	  *.la | *.lo) ;;  # We handle these cases below.
+	  force)
+	    if test no = "$dlself"; then
+	      dlself=needless
+	      export_dynamic=yes
+	    fi
+	    prev=
+	    continue
+	    ;;
+	  self)
+	    if test dlprefiles = "$prev"; then
+	      dlself=yes
+	    elif test dlfiles = "$prev" && test yes != "$dlopen_self"; then
+	      dlself=yes
+	    else
+	      dlself=needless
+	      export_dynamic=yes
+	    fi
+	    prev=
+	    continue
+	    ;;
+	  *)
+	    if test dlfiles = "$prev"; then
+	      func_append dlfiles " $arg"
+	    else
+	      func_append dlprefiles " $arg"
+	    fi
+	    prev=
+	    continue
+	    ;;
+	  esac
+	  ;;
+	expsyms)
+	  export_symbols=$arg
+	  test -f "$arg" \
+	    || func_fatal_error "symbol file '$arg' does not exist"
+	  prev=
+	  continue
+	  ;;
+	expsyms_regex)
+	  export_symbols_regex=$arg
+	  prev=
+	  continue
+	  ;;
+	framework)
+	  case $host in
+	    *-*-darwin*)
+	      case "$deplibs " in
+		*" $qarg.ltframework "*) ;;
+		*) func_append deplibs " $qarg.ltframework" # this is fixed later
+		   ;;
+	      esac
+	      ;;
+	  esac
+	  prev=
+	  continue
+	  ;;
+	inst_prefix)
+	  inst_prefix_dir=$arg
+	  prev=
+	  continue
+	  ;;
+	mllvm)
+	  # Clang does not use LLVM to link, so we can simply discard any
+	  # '-mllvm $arg' options when doing the link step.
+	  prev=
+	  continue
+	  ;;
+	objectlist)
+	  if test -f "$arg"; then
+	    save_arg=$arg
+	    moreargs=
+	    for fil in `cat "$save_arg"`
+	    do
+#	      func_append moreargs " $fil"
+	      arg=$fil
+	      # A libtool-controlled object.
+
+	      # Check to see that this really is a libtool object.
+	      if func_lalib_unsafe_p "$arg"; then
+		pic_object=
+		non_pic_object=
+
+		# Read the .lo file
+		func_source "$arg"
+
+		if test -z "$pic_object" ||
+		   test -z "$non_pic_object" ||
+		   test none = "$pic_object" &&
+		   test none = "$non_pic_object"; then
+		  func_fatal_error "cannot find name of object for '$arg'"
+		fi
+
+		# Extract subdirectory from the argument.
+		func_dirname "$arg" "/" ""
+		xdir=$func_dirname_result
+
+		if test none != "$pic_object"; then
+		  # Prepend the subdirectory the object is found in.
+		  pic_object=$xdir$pic_object
+
+		  if test dlfiles = "$prev"; then
+		    if test yes = "$build_libtool_libs" && test yes = "$dlopen_support"; then
+		      func_append dlfiles " $pic_object"
+		      prev=
+		      continue
+		    else
+		      # If libtool objects are unsupported, then we need to preload.
+		      prev=dlprefiles
+		    fi
+		  fi
+
+		  # CHECK ME:  I think I busted this.  -Ossama
+		  if test dlprefiles = "$prev"; then
+		    # Preload the old-style object.
+		    func_append dlprefiles " $pic_object"
+		    prev=
+		  fi
+
+		  # A PIC object.
+		  func_append libobjs " $pic_object"
+		  arg=$pic_object
+		fi
+
+		# Non-PIC object.
+		if test none != "$non_pic_object"; then
+		  # Prepend the subdirectory the object is found in.
+		  non_pic_object=$xdir$non_pic_object
+
+		  # A standard non-PIC object
+		  func_append non_pic_objects " $non_pic_object"
+		  if test -z "$pic_object" || test none = "$pic_object"; then
+		    arg=$non_pic_object
+		  fi
+		else
+		  # If the PIC object exists, use it instead.
+		  # $xdir was prepended to $pic_object above.
+		  non_pic_object=$pic_object
+		  func_append non_pic_objects " $non_pic_object"
+		fi
+	      else
+		# Only an error if not doing a dry-run.
+		if $opt_dry_run; then
+		  # Extract subdirectory from the argument.
+		  func_dirname "$arg" "/" ""
+		  xdir=$func_dirname_result
+
+		  func_lo2o "$arg"
+		  pic_object=$xdir$objdir/$func_lo2o_result
+		  non_pic_object=$xdir$func_lo2o_result
+		  func_append libobjs " $pic_object"
+		  func_append non_pic_objects " $non_pic_object"
+	        else
+		  func_fatal_error "'$arg' is not a valid libtool object"
+		fi
+	      fi
+	    done
+	  else
+	    func_fatal_error "link input file '$arg' does not exist"
+	  fi
+	  arg=$save_arg
+	  prev=
+	  continue
+	  ;;
+	os2dllname)
+	  os2dllname=$arg
+	  prev=
+	  continue
+	  ;;
+	precious_regex)
+	  precious_files_regex=$arg
+	  prev=
+	  continue
+	  ;;
+	release)
+	  release=-$arg
+	  prev=
+	  continue
+	  ;;
+	rpath | xrpath)
+	  # We need an absolute path.
+	  case $arg in
+	  [\\/]* | [A-Za-z]:[\\/]*) ;;
+	  *)
+	    func_fatal_error "only absolute run-paths are allowed"
+	    ;;
+	  esac
+	  if test rpath = "$prev"; then
+	    case "$rpath " in
+	    *" $arg "*) ;;
+	    *) func_append rpath " $arg" ;;
+	    esac
+	  else
+	    case "$xrpath " in
+	    *" $arg "*) ;;
+	    *) func_append xrpath " $arg" ;;
+	    esac
+	  fi
+	  prev=
+	  continue
+	  ;;
+	shrext)
+	  shrext_cmds=$arg
+	  prev=
+	  continue
+	  ;;
+	weak)
+	  func_append weak_libs " $arg"
+	  prev=
+	  continue
+	  ;;
+	xassembler)
+	  func_append compiler_flags " -Xassembler $qarg"
+	  prev=
+	  func_append compile_command " -Xassembler $qarg"
+	  func_append finalize_command " -Xassembler $qarg"
+	  continue
+	  ;;
+	xcclinker)
+	  func_append linker_flags " $qarg"
+	  func_append compiler_flags " $qarg"
+	  prev=
+	  func_append compile_command " $qarg"
+	  func_append finalize_command " $qarg"
+	  continue
+	  ;;
+	xcompiler)
+	  func_append compiler_flags " $qarg"
+	  prev=
+	  func_append compile_command " $qarg"
+	  func_append finalize_command " $qarg"
+	  continue
+	  ;;
+	xlinker)
+	  func_append linker_flags " $qarg"
+	  func_append compiler_flags " $wl$qarg"
+	  prev=
+	  func_append compile_command " $wl$qarg"
+	  func_append finalize_command " $wl$qarg"
+	  continue
+	  ;;
+	*)
+	  eval "$prev=\"\$arg\""
+	  prev=
+	  continue
+	  ;;
+	esac
+      fi # test -n "$prev"
+
+      prevarg=$arg
+
+      case $arg in
+      -all-static)
+	if test -n "$link_static_flag"; then
+	  # See comment for -static flag below, for more details.
+	  func_append compile_command " $link_static_flag"
+	  func_append finalize_command " $link_static_flag"
+	fi
+	continue
+	;;
+
+      -allow-undefined)
+	# FIXME: remove this flag sometime in the future.
+	func_fatal_error "'-allow-undefined' must not be used because it is the default"
+	;;
+
+      -avoid-version)
+	avoid_version=yes
+	continue
+	;;
+
+      -bindir)
+	prev=bindir
+	continue
+	;;
+
+      -dlopen)
+	prev=dlfiles
+	continue
+	;;
+
+      -dlpreopen)
+	prev=dlprefiles
+	continue
+	;;
+
+      -export-dynamic)
+	export_dynamic=yes
+	continue
+	;;
+
+      -export-symbols | -export-symbols-regex)
+	if test -n "$export_symbols" || test -n "$export_symbols_regex"; then
+	  func_fatal_error "more than one -exported-symbols argument is not allowed"
+	fi
+	if test X-export-symbols = "X$arg"; then
+	  prev=expsyms
+	else
+	  prev=expsyms_regex
+	fi
+	continue
+	;;
+
+      -framework)
+	prev=framework
+	continue
+	;;
+
+      -inst-prefix-dir)
+	prev=inst_prefix
+	continue
+	;;
+
+      # The native IRIX linker understands -LANG:*, -LIST:* and -LNO:*
+      # so, if we see these flags be careful not to treat them like -L
+      -L[A-Z][A-Z]*:*)
+	case $with_gcc/$host in
+	no/*-*-irix* | /*-*-irix*)
+	  func_append compile_command " $arg"
+	  func_append finalize_command " $arg"
+	  ;;
+	esac
+	continue
+	;;
+
+      -L*)
+	func_stripname "-L" '' "$arg"
+	if test -z "$func_stripname_result"; then
+	  if test "$#" -gt 0; then
+	    func_fatal_error "require no space between '-L' and '$1'"
+	  else
+	    func_fatal_error "need path for '-L' option"
+	  fi
+	fi
+	func_resolve_sysroot "$func_stripname_result"
+	dir=$func_resolve_sysroot_result
+	# We need an absolute path.
+	case $dir in
+	[\\/]* | [A-Za-z]:[\\/]*) ;;
+	*)
+	  absdir=`cd "$dir" && pwd`
+	  test -z "$absdir" && \
+	    func_fatal_error "cannot determine absolute directory name of '$dir'"
+	  dir=$absdir
+	  ;;
+	esac
+	case "$deplibs " in
+	*" -L$dir "* | *" $arg "*)
+	  # Will only happen for absolute or sysroot arguments
+	  ;;
+	*)
+	  # Preserve sysroot, but never include relative directories
+	  case $dir in
+	    [\\/]* | [A-Za-z]:[\\/]* | =*) func_append deplibs " $arg" ;;
+	    *) func_append deplibs " -L$dir" ;;
+	  esac
+	  func_append lib_search_path " $dir"
+	  ;;
+	esac
+	case $host in
+	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
+	  testbindir=`$ECHO "$dir" | $SED 's*/lib$*/bin*'`
+	  case :$dllsearchpath: in
+	  *":$dir:"*) ;;
+	  ::) dllsearchpath=$dir;;
+	  *) func_append dllsearchpath ":$dir";;
+	  esac
+	  case :$dllsearchpath: in
+	  *":$testbindir:"*) ;;
+	  ::) dllsearchpath=$testbindir;;
+	  *) func_append dllsearchpath ":$testbindir";;
+	  esac
+	  ;;
+	esac
+	continue
+	;;
+
+      -l*)
+	if test X-lc = "X$arg" || test X-lm = "X$arg"; then
+	  case $host in
+	  *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-beos* | *-cegcc* | *-*-haiku*)
+	    # These systems don't actually have a C or math library (as such)
+	    continue
+	    ;;
+	  *-*-os2*)
+	    # These systems don't actually have a C library (as such)
+	    test X-lc = "X$arg" && continue
+	    ;;
+	  *-*-openbsd* | *-*-freebsd* | *-*-dragonfly* | *-*-bitrig* | *-*-midnightbsd*)
+	    # Do not include libc due to us having libc/libc_r.
+	    test X-lc = "X$arg" && continue
+	    ;;
+	  *-*-rhapsody* | *-*-darwin1.[012])
+	    # Rhapsody C and math libraries are in the System framework
+	    func_append deplibs " System.ltframework"
+	    continue
+	    ;;
+	  *-*-sco3.2v5* | *-*-sco5v6*)
+	    # Causes problems with __ctype
+	    test X-lc = "X$arg" && continue
+	    ;;
+	  *-*-sysv4.2uw2* | *-*-sysv5* | *-*-unixware* | *-*-OpenUNIX*)
+	    # Compiler inserts libc in the correct place for threads to work
+	    test X-lc = "X$arg" && continue
+	    ;;
+	  esac
+	elif test X-lc_r = "X$arg"; then
+	 case $host in
+	 *-*-openbsd* | *-*-freebsd* | *-*-dragonfly* | *-*-bitrig* | *-*-midnightbsd*)
+	   # Do not include libc_r directly, use -pthread flag.
+	   continue
+	   ;;
+	 esac
+	fi
+	func_append deplibs " $arg"
+	continue
+	;;
+
+      -mllvm)
+	prev=mllvm
+	continue
+	;;
+
+      -module)
+	module=yes
+	continue
+	;;
+
+      # Tru64 UNIX uses -model [arg] to determine the layout of C++
+      # classes, name mangling, and exception handling.
+      # Darwin uses the -arch flag to determine output architecture.
+      -model|-arch|-isysroot|--sysroot)
+	func_append compiler_flags " $arg"
+	func_append compile_command " $arg"
+	func_append finalize_command " $arg"
+	prev=xcompiler
+	continue
+	;;
+     # Solaris ld rejects as of 11.4. Refer to Oracle bug 22985199.
+     -pthread)
+	case $host in
+	  *solaris2*) ;;
+	  *)
+	    case "$new_inherited_linker_flags " in
+	        *" $arg "*) ;;
+	        * ) func_append new_inherited_linker_flags " $arg" ;;
+	    esac
+	  ;;
+	esac
+	continue
+	;;
+      -mt|-mthreads|-kthread|-Kthread|-pthreads|--thread-safe \
+      |-threads|-fopenmp|-openmp|-mp|-xopenmp|-omp|-qsmp=*)
+	func_append compiler_flags " $arg"
+	func_append compile_command " $arg"
+	func_append finalize_command " $arg"
+	case "$new_inherited_linker_flags " in
+	    *" $arg "*) ;;
+	    * ) func_append new_inherited_linker_flags " $arg" ;;
+	esac
+	continue
+	;;
+
+      -multi_module)
+	single_module=$wl-multi_module
+	continue
+	;;
+
+      -no-fast-install)
+	fast_install=no
+	continue
+	;;
+
+      -no-install)
+	case $host in
+	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-darwin* | *-cegcc*)
+	  # The PATH hackery in wrapper scripts is required on Windows
+	  # and Darwin in order for the loader to find any dlls it needs.
+	  func_warning "'-no-install' is ignored for $host"
+	  func_warning "assuming '-no-fast-install' instead"
+	  fast_install=no
+	  ;;
+	*) no_install=yes ;;
+	esac
+	continue
+	;;
+
+      -no-undefined)
+	allow_undefined=no
+	continue
+	;;
+
+      -objectlist)
+	prev=objectlist
+	continue
+	;;
+
+      -os2dllname)
+	prev=os2dllname
+	continue
+	;;
+
+      -o) prev=output ;;
+
+      -precious-files-regex)
+	prev=precious_regex
+	continue
+	;;
+
+      -release)
+	prev=release
+	continue
+	;;
+
+      -rpath)
+	prev=rpath
+	continue
+	;;
+
+      -R)
+	prev=xrpath
+	continue
+	;;
+
+      -R*)
+	func_stripname '-R' '' "$arg"
+	dir=$func_stripname_result
+	# We need an absolute path.
+	case $dir in
+	[\\/]* | [A-Za-z]:[\\/]*) ;;
+	=*)
+	  func_stripname '=' '' "$dir"
+	  dir=$lt_sysroot$func_stripname_result
+	  ;;
+	*)
+	  func_fatal_error "only absolute run-paths are allowed"
+	  ;;
+	esac
+	case "$xrpath " in
+	*" $dir "*) ;;
+	*) func_append xrpath " $dir" ;;
+	esac
+	continue
+	;;
+
+      -shared)
+	# The effects of -shared are defined in a previous loop.
+	continue
+	;;
+
+      -shrext)
+	prev=shrext
+	continue
+	;;
+
+      -static | -static-libtool-libs)
+	# The effects of -static are defined in a previous loop.
+	# We used to do the same as -all-static on platforms that
+	# didn't have a PIC flag, but the assumption that the effects
+	# would be equivalent was wrong.  It would break on at least
+	# Digital Unix and AIX.
+	continue
+	;;
+
+      -thread-safe)
+	thread_safe=yes
+	continue
+	;;
+
+      -version-info)
+	prev=vinfo
+	continue
+	;;
+
+      -version-number)
+	prev=vinfo
+	vinfo_number=yes
+	continue
+	;;
+
+      -weak)
+        prev=weak
+	continue
+	;;
+
+      -Wc,*)
+	func_stripname '-Wc,' '' "$arg"
+	args=$func_stripname_result
+	arg=
+	save_ifs=$IFS; IFS=,
+	for flag in $args; do
+	  IFS=$save_ifs
+          func_quote_arg pretty "$flag"
+	  func_append arg " $func_quote_arg_result"
+	  func_append compiler_flags " $func_quote_arg_result"
+	done
+	IFS=$save_ifs
+	func_stripname ' ' '' "$arg"
+	arg=$func_stripname_result
+	;;
+
+      -Wl,*)
+	func_stripname '-Wl,' '' "$arg"
+	args=$func_stripname_result
+	arg=
+	save_ifs=$IFS; IFS=,
+	for flag in $args; do
+	  IFS=$save_ifs
+          func_quote_arg pretty "$flag"
+	  func_append arg " $wl$func_quote_arg_result"
+	  func_append compiler_flags " $wl$func_quote_arg_result"
+	  func_append linker_flags " $func_quote_arg_result"
+	done
+	IFS=$save_ifs
+	func_stripname ' ' '' "$arg"
+	arg=$func_stripname_result
+	;;
+
+      -Xassembler)
+        prev=xassembler
+        continue
+        ;;
+
+      -Xcompiler)
+	prev=xcompiler
+	continue
+	;;
+
+      -Xlinker)
+	prev=xlinker
+	continue
+	;;
+
+      -XCClinker)
+	prev=xcclinker
+	continue
+	;;
+
+      # -msg_* for osf cc
+      -msg_*)
+	func_quote_arg pretty "$arg"
+	arg=$func_quote_arg_result
+	;;
+
+      # Flags to be passed through unchanged, with rationale:
+      # -64, -mips[0-9]      enable 64-bit mode for the SGI compiler
+      # -r[0-9][0-9]*        specify processor for the SGI compiler
+      # -xarch=*, -xtarget=* enable 64-bit mode for the Sun compiler
+      # +DA*, +DD*           enable 64-bit mode for the HP compiler
+      # -q*                  compiler args for the IBM compiler
+      # -m*, -t[45]*, -txscale* architecture-specific flags for GCC
+      # -F/path              path to uninstalled frameworks, gcc on darwin
+      # -p, -pg, --coverage, -fprofile-*  profiling flags for GCC
+      # -fstack-protector*   stack protector flags for GCC
+      # @file                GCC response files
+      # -tp=*                Portland pgcc target processor selection
+      # --sysroot=*          for sysroot support
+      # -O*, -g*, -flto*, -fwhopr*, -fuse-linker-plugin GCC link-time optimization
+      # -specs=*             GCC specs files
+      # -stdlib=*            select c++ std lib with clang
+      # -fsanitize=*         Clang/GCC memory and address sanitizer
+      # -fuse-ld=*           Linker select flags for GCC
+      # -Wa,*                Pass flags directly to the assembler
+      -64|-mips[0-9]|-r[0-9][0-9]*|-xarch=*|-xtarget=*|+DA*|+DD*|-q*|-m*| \
+      -t[45]*|-txscale*|-p|-pg|--coverage|-fprofile-*|-F*|@*|-tp=*|--sysroot=*| \
+      -O*|-g*|-flto*|-fwhopr*|-fuse-linker-plugin|-fstack-protector*|-stdlib=*| \
+      -specs=*|-fsanitize=*|-fuse-ld=*|-Wa,*)
+        func_quote_arg pretty "$arg"
+	arg=$func_quote_arg_result
+        func_append compile_command " $arg"
+        func_append finalize_command " $arg"
+        func_append compiler_flags " $arg"
+        continue
+        ;;
+
+      -Z*)
+        if test os2 = "`expr $host : '.*\(os2\)'`"; then
+          # OS/2 uses -Zxxx to specify OS/2-specific options
+	  compiler_flags="$compiler_flags $arg"
+	  func_append compile_command " $arg"
+	  func_append finalize_command " $arg"
+	  case $arg in
+	  -Zlinker | -Zstack)
+	    prev=xcompiler
+	    ;;
+	  esac
+	  continue
+        else
+	  # Otherwise treat like 'Some other compiler flag' below
+	  func_quote_arg pretty "$arg"
+	  arg=$func_quote_arg_result
+        fi
+	;;
+
+      # Some other compiler flag.
+      -* | +*)
+        func_quote_arg pretty "$arg"
+	arg=$func_quote_arg_result
+	;;
+
+      *.$objext)
+	# A standard object.
+	func_append objs " $arg"
+	;;
+
+      *.lo)
+	# A libtool-controlled object.
+
+	# Check to see that this really is a libtool object.
+	if func_lalib_unsafe_p "$arg"; then
+	  pic_object=
+	  non_pic_object=
+
+	  # Read the .lo file
+	  func_source "$arg"
+
+	  if test -z "$pic_object" ||
+	     test -z "$non_pic_object" ||
+	     test none = "$pic_object" &&
+	     test none = "$non_pic_object"; then
+	    func_fatal_error "cannot find name of object for '$arg'"
+	  fi
+
+	  # Extract subdirectory from the argument.
+	  func_dirname "$arg" "/" ""
+	  xdir=$func_dirname_result
+
+	  test none = "$pic_object" || {
+	    # Prepend the subdirectory the object is found in.
+	    pic_object=$xdir$pic_object
+
+	    if test dlfiles = "$prev"; then
+	      if test yes = "$build_libtool_libs" && test yes = "$dlopen_support"; then
+		func_append dlfiles " $pic_object"
+		prev=
+		continue
+	      else
+		# If libtool objects are unsupported, then we need to preload.
+		prev=dlprefiles
+	      fi
+	    fi
+
+	    # CHECK ME:  I think I busted this.  -Ossama
+	    if test dlprefiles = "$prev"; then
+	      # Preload the old-style object.
+	      func_append dlprefiles " $pic_object"
+	      prev=
+	    fi
+
+	    # A PIC object.
+	    func_append libobjs " $pic_object"
+	    arg=$pic_object
+	  }
+
+	  # Non-PIC object.
+	  if test none != "$non_pic_object"; then
+	    # Prepend the subdirectory the object is found in.
+	    non_pic_object=$xdir$non_pic_object
+
+	    # A standard non-PIC object
+	    func_append non_pic_objects " $non_pic_object"
+	    if test -z "$pic_object" || test none = "$pic_object"; then
+	      arg=$non_pic_object
+	    fi
+	  else
+	    # If the PIC object exists, use it instead.
+	    # $xdir was prepended to $pic_object above.
+	    non_pic_object=$pic_object
+	    func_append non_pic_objects " $non_pic_object"
+	  fi
+	else
+	  # Only an error if not doing a dry-run.
+	  if $opt_dry_run; then
+	    # Extract subdirectory from the argument.
+	    func_dirname "$arg" "/" ""
+	    xdir=$func_dirname_result
+
+	    func_lo2o "$arg"
+	    pic_object=$xdir$objdir/$func_lo2o_result
+	    non_pic_object=$xdir$func_lo2o_result
+	    func_append libobjs " $pic_object"
+	    func_append non_pic_objects " $non_pic_object"
+	  else
+	    func_fatal_error "'$arg' is not a valid libtool object"
+	  fi
+	fi
+	;;
+
+      *.$libext)
+	# An archive.
+	func_append deplibs " $arg"
+	func_append old_deplibs " $arg"
+	continue
+	;;
+
+      *.la)
+	# A libtool-controlled library.
+
+	func_resolve_sysroot "$arg"
+	if test dlfiles = "$prev"; then
+	  # This library was specified with -dlopen.
+	  func_append dlfiles " $func_resolve_sysroot_result"
+	  prev=
+	elif test dlprefiles = "$prev"; then
+	  # The library was specified with -dlpreopen.
+	  func_append dlprefiles " $func_resolve_sysroot_result"
+	  prev=
+	else
+	  func_append deplibs " $func_resolve_sysroot_result"
+	fi
+	continue
+	;;
+
+      # Some other compiler argument.
+      *)
+	# Unknown arguments in both finalize_command and compile_command need
+	# to be aesthetically quoted because they are evaled later.
+	func_quote_arg pretty "$arg"
+	arg=$func_quote_arg_result
+	;;
+      esac # arg
+
+      # Now actually substitute the argument into the commands.
+      if test -n "$arg"; then
+	func_append compile_command " $arg"
+	func_append finalize_command " $arg"
+      fi
+    done # argument parsing loop
+
+    test -n "$prev" && \
+      func_fatal_help "the '$prevarg' option requires an argument"
+
+    if test yes = "$export_dynamic" && test -n "$export_dynamic_flag_spec"; then
+      eval arg=\"$export_dynamic_flag_spec\"
+      func_append compile_command " $arg"
+      func_append finalize_command " $arg"
+    fi
+
+    oldlibs=
+    # calculate the name of the file, without its directory
+    func_basename "$output"
+    outputname=$func_basename_result
+    libobjs_save=$libobjs
+
+    if test -n "$shlibpath_var"; then
+      # get the directories listed in $shlibpath_var
+      eval shlib_search_path=\`\$ECHO \"\$$shlibpath_var\" \| \$SED \'s/:/ /g\'\`
+    else
+      shlib_search_path=
+    fi
+    eval sys_lib_search_path=\"$sys_lib_search_path_spec\"
+    eval sys_lib_dlsearch_path=\"$sys_lib_dlsearch_path_spec\"
+
+    # Definition is injected by LT_CONFIG during libtool generation.
+    func_munge_path_list sys_lib_dlsearch_path "$LT_SYS_LIBRARY_PATH"
+
+    func_dirname "$output" "/" ""
+    output_objdir=$func_dirname_result$objdir
+    func_to_tool_file "$output_objdir/"
+    tool_output_objdir=$func_to_tool_file_result
+    # Create the object directory.
+    func_mkdir_p "$output_objdir"
+
+    # Determine the type of output
+    case $output in
+    "")
+      func_fatal_help "you must specify an output file"
+      ;;
+    *.$libext) linkmode=oldlib ;;
+    *.lo | *.$objext) linkmode=obj ;;
+    *.la) linkmode=lib ;;
+    *) linkmode=prog ;; # Anything else should be a program.
+    esac
+
+    specialdeplibs=
+
+    libs=
+    # Find all interdependent deplibs by searching for libraries
+    # that are linked more than once (e.g. -la -lb -la)
+    for deplib in $deplibs; do
+      if $opt_preserve_dup_deps; then
+	case "$libs " in
+	*" $deplib "*) func_append specialdeplibs " $deplib" ;;
+	esac
+      fi
+      func_append libs " $deplib"
+    done
+
+    if test lib = "$linkmode"; then
+      libs="$predeps $libs $compiler_lib_search_path $postdeps"
+
+      # Compute libraries that are listed more than once in $predeps
+      # $postdeps and mark them as special (i.e., whose duplicates are
+      # not to be eliminated).
+      pre_post_deps=
+      if $opt_duplicate_compiler_generated_deps; then
+	for pre_post_dep in $predeps $postdeps; do
+	  case "$pre_post_deps " in
+	  *" $pre_post_dep "*) func_append specialdeplibs " $pre_post_deps" ;;
+	  esac
+	  func_append pre_post_deps " $pre_post_dep"
+	done
+      fi
+      pre_post_deps=
+    fi
+
+    deplibs=
+    newdependency_libs=
+    newlib_search_path=
+    need_relink=no # whether we're linking any uninstalled libtool libraries
+    notinst_deplibs= # not-installed libtool libraries
+    notinst_path= # paths that contain not-installed libtool libraries
+
+    case $linkmode in
+    lib)
+	passes="conv dlpreopen link"
+	for file in $dlfiles $dlprefiles; do
+	  case $file in
+	  *.la) ;;
+	  *)
+	    func_fatal_help "libraries can '-dlopen' only libtool libraries: $file"
+	    ;;
+	  esac
+	done
+	;;
+    prog)
+	compile_deplibs=
+	finalize_deplibs=
+	alldeplibs=false
+	newdlfiles=
+	newdlprefiles=
+	passes="conv scan dlopen dlpreopen link"
+	;;
+    *)  passes="conv"
+	;;
+    esac
+
+    for pass in $passes; do
+      # The preopen pass in lib mode reverses $deplibs; put it back here
+      # so that -L comes before libs that need it for instance...
+      if test lib,link = "$linkmode,$pass"; then
+	## FIXME: Find the place where the list is rebuilt in the wrong
+	##        order, and fix it there properly
+        tmp_deplibs=
+	for deplib in $deplibs; do
+	  tmp_deplibs="$deplib $tmp_deplibs"
+	done
+	deplibs=$tmp_deplibs
+      fi
+
+      if test lib,link = "$linkmode,$pass" ||
+	 test prog,scan = "$linkmode,$pass"; then
+	libs=$deplibs
+	deplibs=
+      fi
+      if test prog = "$linkmode"; then
+	case $pass in
+	dlopen) libs=$dlfiles ;;
+	dlpreopen) libs=$dlprefiles ;;
+	link) libs="$deplibs %DEPLIBS% $dependency_libs" ;;
+	esac
+      fi
+      if test lib,dlpreopen = "$linkmode,$pass"; then
+	# Collect and forward deplibs of preopened libtool libs
+	for lib in $dlprefiles; do
+	  # Ignore non-libtool-libs
+	  dependency_libs=
+	  func_resolve_sysroot "$lib"
+	  case $lib in
+	  *.la)	func_source "$func_resolve_sysroot_result" ;;
+	  esac
+
+	  # Collect preopened libtool deplibs, except any this library
+	  # has declared as weak libs
+	  for deplib in $dependency_libs; do
+	    func_basename "$deplib"
+            deplib_base=$func_basename_result
+	    case " $weak_libs " in
+	    *" $deplib_base "*) ;;
+	    *) func_append deplibs " $deplib" ;;
+	    esac
+	  done
+	done
+	libs=$dlprefiles
+      fi
+      if test dlopen = "$pass"; then
+	# Collect dlpreopened libraries
+	save_deplibs=$deplibs
+	deplibs=
+      fi
+
+      for deplib in $libs; do
+	lib=
+	found=false
+	case $deplib in
+	-mt|-mthreads|-kthread|-Kthread|-pthread|-pthreads|--thread-safe \
+        |-threads|-fopenmp|-openmp|-mp|-xopenmp|-omp|-qsmp=*)
+	  if test prog,link = "$linkmode,$pass"; then
+	    compile_deplibs="$deplib $compile_deplibs"
+	    finalize_deplibs="$deplib $finalize_deplibs"
+	  else
+	    func_append compiler_flags " $deplib"
+	    if test lib = "$linkmode"; then
+		case "$new_inherited_linker_flags " in
+		    *" $deplib "*) ;;
+		    * ) func_append new_inherited_linker_flags " $deplib" ;;
+		esac
+	    fi
+	  fi
+	  continue
+	  ;;
+	-l*)
+	  if test lib != "$linkmode" && test prog != "$linkmode"; then
+	    func_warning "'-l' is ignored for archives/objects"
+	    continue
+	  fi
+	  func_stripname '-l' '' "$deplib"
+	  name=$func_stripname_result
+	  if test lib = "$linkmode"; then
+	    searchdirs="$newlib_search_path $lib_search_path $compiler_lib_search_dirs $sys_lib_search_path $shlib_search_path"
+	  else
+	    searchdirs="$newlib_search_path $lib_search_path $sys_lib_search_path $shlib_search_path"
+	  fi
+	  for searchdir in $searchdirs; do
+	    for search_ext in .la $std_shrext .so .a; do
+	      # Search the libtool library
+	      lib=$searchdir/lib$name$search_ext
+	      if test -f "$lib"; then
+		if test .la = "$search_ext"; then
+		  found=:
+		else
+		  found=false
+		fi
+		break 2
+	      fi
+	    done
+	  done
+	  if $found; then
+	    # deplib is a libtool library
+	    # If $allow_libtool_libs_with_static_runtimes && $deplib is a stdlib,
+	    # We need to do some special things here, and not later.
+	    if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+	      case " $predeps $postdeps " in
+	      *" $deplib "*)
+		if func_lalib_p "$lib"; then
+		  library_names=
+		  old_library=
+		  func_source "$lib"
+		  for l in $old_library $library_names; do
+		    ll=$l
+		  done
+		  if test "X$ll" = "X$old_library"; then # only static version available
+		    found=false
+		    func_dirname "$lib" "" "."
+		    ladir=$func_dirname_result
+		    lib=$ladir/$old_library
+		    if test prog,link = "$linkmode,$pass"; then
+		      compile_deplibs="$deplib $compile_deplibs"
+		      finalize_deplibs="$deplib $finalize_deplibs"
+		    else
+		      deplibs="$deplib $deplibs"
+		      test lib = "$linkmode" && newdependency_libs="$deplib $newdependency_libs"
+		    fi
+		    continue
+		  fi
+		fi
+		;;
+	      *) ;;
+	      esac
+	    fi
+	  else
+	    # deplib doesn't seem to be a libtool library
+	    if test prog,link = "$linkmode,$pass"; then
+	      compile_deplibs="$deplib $compile_deplibs"
+	      finalize_deplibs="$deplib $finalize_deplibs"
+	    else
+	      deplibs="$deplib $deplibs"
+	      test lib = "$linkmode" && newdependency_libs="$deplib $newdependency_libs"
+	    fi
+	    continue
+	  fi
+	  ;; # -l
+	*.ltframework)
+	  if test prog,link = "$linkmode,$pass"; then
+	    compile_deplibs="$deplib $compile_deplibs"
+	    finalize_deplibs="$deplib $finalize_deplibs"
+	  else
+	    deplibs="$deplib $deplibs"
+	    if test lib = "$linkmode"; then
+		case "$new_inherited_linker_flags " in
+		    *" $deplib "*) ;;
+		    * ) func_append new_inherited_linker_flags " $deplib" ;;
+		esac
+	    fi
+	  fi
+	  continue
+	  ;;
+	-L*)
+	  case $linkmode in
+	  lib)
+	    deplibs="$deplib $deplibs"
+	    test conv = "$pass" && continue
+	    newdependency_libs="$deplib $newdependency_libs"
+	    func_stripname '-L' '' "$deplib"
+	    func_resolve_sysroot "$func_stripname_result"
+	    func_append newlib_search_path " $func_resolve_sysroot_result"
+	    ;;
+	  prog)
+	    if test conv = "$pass"; then
+	      deplibs="$deplib $deplibs"
+	      continue
+	    fi
+	    if test scan = "$pass"; then
+	      deplibs="$deplib $deplibs"
+	    else
+	      compile_deplibs="$deplib $compile_deplibs"
+	      finalize_deplibs="$deplib $finalize_deplibs"
+	    fi
+	    func_stripname '-L' '' "$deplib"
+	    func_resolve_sysroot "$func_stripname_result"
+	    func_append newlib_search_path " $func_resolve_sysroot_result"
+	    ;;
+	  *)
+	    func_warning "'-L' is ignored for archives/objects"
+	    ;;
+	  esac # linkmode
+	  continue
+	  ;; # -L
+	-R*)
+	  if test link = "$pass"; then
+	    func_stripname '-R' '' "$deplib"
+	    func_resolve_sysroot "$func_stripname_result"
+	    dir=$func_resolve_sysroot_result
+	    # Make sure the xrpath contains only unique directories.
+	    case "$xrpath " in
+	    *" $dir "*) ;;
+	    *) func_append xrpath " $dir" ;;
+	    esac
+	  fi
+	  deplibs="$deplib $deplibs"
+	  continue
+	  ;;
+	*.la)
+	  func_resolve_sysroot "$deplib"
+	  lib=$func_resolve_sysroot_result
+	  ;;
+	*.$libext)
+	  if test conv = "$pass"; then
+	    deplibs="$deplib $deplibs"
+	    continue
+	  fi
+	  case $linkmode in
+	  lib)
+	    # Linking convenience modules into shared libraries is allowed,
+	    # but linking other static libraries is non-portable.
+	    case " $dlpreconveniencelibs " in
+	    *" $deplib "*) ;;
+	    *)
+	      valid_a_lib=false
+	      case $deplibs_check_method in
+		match_pattern*)
+		  set dummy $deplibs_check_method; shift
+		  match_pattern_regex=`expr "$deplibs_check_method" : "$1 \(.*\)"`
+		  if eval "\$ECHO \"$deplib\"" 2>/dev/null | $SED 10q \
+		    | $EGREP "$match_pattern_regex" > /dev/null; then
+		    valid_a_lib=:
+		  fi
+		;;
+		pass_all)
+		  valid_a_lib=:
+		;;
+	      esac
+	      if $valid_a_lib; then
+		echo
+		$ECHO "*** Warning: Linking the shared library $output against the"
+		$ECHO "*** static library $deplib is not portable!"
+		deplibs="$deplib $deplibs"
+	      else
+		echo
+		$ECHO "*** Warning: Trying to link with static lib archive $deplib."
+		echo "*** I have the capability to make that library automatically link in when"
+		echo "*** you link to this library.  But I can only do this if you have a"
+		echo "*** shared version of the library, which you do not appear to have"
+		echo "*** because the file extensions .$libext of this argument makes me believe"
+		echo "*** that it is just a static archive that I should not use here."
+	      fi
+	      ;;
+	    esac
+	    continue
+	    ;;
+	  prog)
+	    if test link != "$pass"; then
+	      deplibs="$deplib $deplibs"
+	    else
+	      compile_deplibs="$deplib $compile_deplibs"
+	      finalize_deplibs="$deplib $finalize_deplibs"
+	    fi
+	    continue
+	    ;;
+	  esac # linkmode
+	  ;; # *.$libext
+	*.lo | *.$objext)
+	  if test conv = "$pass"; then
+	    deplibs="$deplib $deplibs"
+	  elif test prog = "$linkmode"; then
+	    if test dlpreopen = "$pass" || test yes != "$dlopen_support" || test no = "$build_libtool_libs"; then
+	      # If there is no dlopen support or we're linking statically,
+	      # we need to preload.
+	      func_append newdlprefiles " $deplib"
+	      compile_deplibs="$deplib $compile_deplibs"
+	      finalize_deplibs="$deplib $finalize_deplibs"
+	    else
+	      func_append newdlfiles " $deplib"
+	    fi
+	  fi
+	  continue
+	  ;;
+	%DEPLIBS%)
+	  alldeplibs=:
+	  continue
+	  ;;
+	esac # case $deplib
+
+	$found || test -f "$lib" \
+	  || func_fatal_error "cannot find the library '$lib' or unhandled argument '$deplib'"
+
+	# Check to see that this really is a libtool archive.
+	func_lalib_unsafe_p "$lib" \
+	  || func_fatal_error "'$lib' is not a valid libtool archive"
+
+	func_dirname "$lib" "" "."
+	ladir=$func_dirname_result
+
+	dlname=
+	dlopen=
+	dlpreopen=
+	libdir=
+	library_names=
+	old_library=
+	inherited_linker_flags=
+	# If the library was installed with an old release of libtool,
+	# it will not redefine variables installed, or shouldnotlink
+	installed=yes
+	shouldnotlink=no
+	avoidtemprpath=
+
+
+	# Read the .la file
+	func_source "$lib"
+
+	# Convert "-framework foo" to "foo.ltframework"
+	if test -n "$inherited_linker_flags"; then
+	  tmp_inherited_linker_flags=`$ECHO "$inherited_linker_flags" | $SED 's/-framework \([^ $]*\)/\1.ltframework/g'`
+	  for tmp_inherited_linker_flag in $tmp_inherited_linker_flags; do
+	    case " $new_inherited_linker_flags " in
+	      *" $tmp_inherited_linker_flag "*) ;;
+	      *) func_append new_inherited_linker_flags " $tmp_inherited_linker_flag";;
+	    esac
+	  done
+	fi
+	dependency_libs=`$ECHO " $dependency_libs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	if test lib,link = "$linkmode,$pass" ||
+	   test prog,scan = "$linkmode,$pass" ||
+	   { test prog != "$linkmode" && test lib != "$linkmode"; }; then
+	  test -n "$dlopen" && func_append dlfiles " $dlopen"
+	  test -n "$dlpreopen" && func_append dlprefiles " $dlpreopen"
+	fi
+
+	if test conv = "$pass"; then
+	  # Only check for convenience libraries
+	  deplibs="$lib $deplibs"
+	  if test -z "$libdir"; then
+	    if test -z "$old_library"; then
+	      func_fatal_error "cannot find name of link library for '$lib'"
+	    fi
+	    # It is a libtool convenience library, so add in its objects.
+	    func_append convenience " $ladir/$objdir/$old_library"
+	    func_append old_convenience " $ladir/$objdir/$old_library"
+	  elif test prog != "$linkmode" && test lib != "$linkmode"; then
+	    func_fatal_error "'$lib' is not a convenience library"
+	  fi
+	  tmp_libs=
+	  for deplib in $dependency_libs; do
+	    deplibs="$deplib $deplibs"
+	    if $opt_preserve_dup_deps; then
+	      case "$tmp_libs " in
+	      *" $deplib "*) func_append specialdeplibs " $deplib" ;;
+	      esac
+	    fi
+	    func_append tmp_libs " $deplib"
+	  done
+	  continue
+	fi # $pass = conv
+
+
+	# Get the name of the library we link against.
+	linklib=
+	if test -n "$old_library" &&
+	   { test yes = "$prefer_static_libs" ||
+	     test built,no = "$prefer_static_libs,$installed"; }; then
+	  linklib=$old_library
+	else
+	  for l in $old_library $library_names; do
+	    linklib=$l
+	  done
+	fi
+	if test -z "$linklib"; then
+	  func_fatal_error "cannot find name of link library for '$lib'"
+	fi
+
+	# This library was specified with -dlopen.
+	if test dlopen = "$pass"; then
+	  test -z "$libdir" \
+	    && func_fatal_error "cannot -dlopen a convenience library: '$lib'"
+	  if test -z "$dlname" ||
+	     test yes != "$dlopen_support" ||
+	     test no = "$build_libtool_libs"
+	  then
+	    # If there is no dlname, no dlopen support or we're linking
+	    # statically, we need to preload.  We also need to preload any
+	    # dependent libraries so libltdl's deplib preloader doesn't
+	    # bomb out in the load deplibs phase.
+	    func_append dlprefiles " $lib $dependency_libs"
+	  else
+	    func_append newdlfiles " $lib"
+	  fi
+	  continue
+	fi # $pass = dlopen
+
+	# We need an absolute path.
+	case $ladir in
+	[\\/]* | [A-Za-z]:[\\/]*) abs_ladir=$ladir ;;
+	*)
+	  abs_ladir=`cd "$ladir" && pwd`
+	  if test -z "$abs_ladir"; then
+	    func_warning "cannot determine absolute directory name of '$ladir'"
+	    func_warning "passing it literally to the linker, although it might fail"
+	    abs_ladir=$ladir
+	  fi
+	  ;;
+	esac
+	func_basename "$lib"
+	laname=$func_basename_result
+
+	# Find the relevant object directory and library name.
+	if test yes = "$installed"; then
+	  if test ! -f "$lt_sysroot$libdir/$linklib" && test -f "$abs_ladir/$linklib"; then
+	    func_warning "library '$lib' was moved."
+	    dir=$ladir
+	    absdir=$abs_ladir
+	    libdir=$abs_ladir
+	  else
+	    dir=$lt_sysroot$libdir
+	    absdir=$lt_sysroot$libdir
+	  fi
+	  test yes = "$hardcode_automatic" && avoidtemprpath=yes
+	else
+	  if test ! -f "$ladir/$objdir/$linklib" && test -f "$abs_ladir/$linklib"; then
+	    dir=$ladir
+	    absdir=$abs_ladir
+	    # Remove this search path later
+	    func_append notinst_path " $abs_ladir"
+	  else
+	    dir=$ladir/$objdir
+	    absdir=$abs_ladir/$objdir
+	    # Remove this search path later
+	    func_append notinst_path " $abs_ladir"
+	  fi
+	fi # $installed = yes
+	func_stripname 'lib' '.la' "$laname"
+	name=$func_stripname_result
+
+	# This library was specified with -dlpreopen.
+	if test dlpreopen = "$pass"; then
+	  if test -z "$libdir" && test prog = "$linkmode"; then
+	    func_fatal_error "only libraries may -dlpreopen a convenience library: '$lib'"
+	  fi
+	  case $host in
+	    # special handling for platforms with PE-DLLs.
+	    *cygwin* | *mingw* | *cegcc* )
+	      # Linker will automatically link against shared library if both
+	      # static and shared are present.  Therefore, ensure we extract
+	      # symbols from the import library if a shared library is present
+	      # (otherwise, the dlopen module name will be incorrect).  We do
+	      # this by putting the import library name into $newdlprefiles.
+	      # We recover the dlopen module name by 'saving' the la file
+	      # name in a special purpose variable, and (later) extracting the
+	      # dlname from the la file.
+	      if test -n "$dlname"; then
+	        func_tr_sh "$dir/$linklib"
+	        eval "libfile_$func_tr_sh_result=\$abs_ladir/\$laname"
+	        func_append newdlprefiles " $dir/$linklib"
+	      else
+	        func_append newdlprefiles " $dir/$old_library"
+	        # Keep a list of preopened convenience libraries to check
+	        # that they are being used correctly in the link pass.
+	        test -z "$libdir" && \
+	          func_append dlpreconveniencelibs " $dir/$old_library"
+	      fi
+	    ;;
+	    * )
+	      # Prefer using a static library (so that no silly _DYNAMIC symbols
+	      # are required to link).
+	      if test -n "$old_library"; then
+	        func_append newdlprefiles " $dir/$old_library"
+	        # Keep a list of preopened convenience libraries to check
+	        # that they are being used correctly in the link pass.
+	        test -z "$libdir" && \
+	          func_append dlpreconveniencelibs " $dir/$old_library"
+	      # Otherwise, use the dlname, so that lt_dlopen finds it.
+	      elif test -n "$dlname"; then
+	        func_append newdlprefiles " $dir/$dlname"
+	      else
+	        func_append newdlprefiles " $dir/$linklib"
+	      fi
+	    ;;
+	  esac
+	fi # $pass = dlpreopen
+
+	if test -z "$libdir"; then
+	  # Link the convenience library
+	  if test lib = "$linkmode"; then
+	    deplibs="$dir/$old_library $deplibs"
+	  elif test prog,link = "$linkmode,$pass"; then
+	    compile_deplibs="$dir/$old_library $compile_deplibs"
+	    finalize_deplibs="$dir/$old_library $finalize_deplibs"
+	  else
+	    deplibs="$lib $deplibs" # used for prog,scan pass
+	  fi
+	  continue
+	fi
+
+
+	if test prog = "$linkmode" && test link != "$pass"; then
+	  func_append newlib_search_path " $ladir"
+	  deplibs="$lib $deplibs"
+
+	  linkalldeplibs=false
+	  if test no != "$link_all_deplibs" || test -z "$library_names" ||
+	     test no = "$build_libtool_libs"; then
+	    linkalldeplibs=:
+	  fi
+
+	  tmp_libs=
+	  for deplib in $dependency_libs; do
+	    case $deplib in
+	    -L*) func_stripname '-L' '' "$deplib"
+	         func_resolve_sysroot "$func_stripname_result"
+	         func_append newlib_search_path " $func_resolve_sysroot_result"
+		 ;;
+	    esac
+	    # Need to link against all dependency_libs?
+	    if $linkalldeplibs; then
+	      deplibs="$deplib $deplibs"
+	    else
+	      # Need to hardcode shared library paths
+	      # or/and link against static libraries
+	      newdependency_libs="$deplib $newdependency_libs"
+	    fi
+	    if $opt_preserve_dup_deps; then
+	      case "$tmp_libs " in
+	      *" $deplib "*) func_append specialdeplibs " $deplib" ;;
+	      esac
+	    fi
+	    func_append tmp_libs " $deplib"
+	  done # for deplib
+	  continue
+	fi # $linkmode = prog...
+
+	if test prog,link = "$linkmode,$pass"; then
+	  if test -n "$library_names" &&
+	     { { test no = "$prefer_static_libs" ||
+	         test built,yes = "$prefer_static_libs,$installed"; } ||
+	       test -z "$old_library"; }; then
+	    # We need to hardcode the library path
+	    if test -n "$shlibpath_var" && test -z "$avoidtemprpath"; then
+	      # Make sure the rpath contains only unique directories.
+	      case $temp_rpath: in
+	      *"$absdir:"*) ;;
+	      *) func_append temp_rpath "$absdir:" ;;
+	      esac
+	    fi
+
+	    # Hardcode the library path.
+	    # Skip directories that are in the system default run-time
+	    # search path.
+	    case " $sys_lib_dlsearch_path " in
+	    *" $absdir "*) ;;
+	    *)
+	      case "$compile_rpath " in
+	      *" $absdir "*) ;;
+	      *) func_append compile_rpath " $absdir" ;;
+	      esac
+	      ;;
+	    esac
+	    case " $sys_lib_dlsearch_path " in
+	    *" $libdir "*) ;;
+	    *)
+	      case "$finalize_rpath " in
+	      *" $libdir "*) ;;
+	      *) func_append finalize_rpath " $libdir" ;;
+	      esac
+	      ;;
+	    esac
+	  fi # $linkmode,$pass = prog,link...
+
+	  if $alldeplibs &&
+	     { test pass_all = "$deplibs_check_method" ||
+	       { test yes = "$build_libtool_libs" &&
+		 test -n "$library_names"; }; }; then
+	    # We only need to search for static libraries
+	    continue
+	  fi
+	fi
+
+	link_static=no # Whether the deplib will be linked statically
+	use_static_libs=$prefer_static_libs
+	if test built = "$use_static_libs" && test yes = "$installed"; then
+	  use_static_libs=no
+	fi
+	if test -n "$library_names" &&
+	   { test no = "$use_static_libs" || test -z "$old_library"; }; then
+	  case $host in
+	  *cygwin* | *mingw* | *cegcc* | *os2*)
+	      # No point in relinking DLLs because paths are not encoded
+	      func_append notinst_deplibs " $lib"
+	      need_relink=no
+	    ;;
+	  *)
+	    if test no = "$installed"; then
+	      func_append notinst_deplibs " $lib"
+	      need_relink=yes
+	    fi
+	    ;;
+	  esac
+	  # This is a shared library
+
+	  # Warn about portability, can't link against -module's on some
+	  # systems (darwin).  Don't bleat about dlopened modules though!
+	  dlopenmodule=
+	  for dlpremoduletest in $dlprefiles; do
+	    if test "X$dlpremoduletest" = "X$lib"; then
+	      dlopenmodule=$dlpremoduletest
+	      break
+	    fi
+	  done
+	  if test -z "$dlopenmodule" && test yes = "$shouldnotlink" && test link = "$pass"; then
+	    echo
+	    if test prog = "$linkmode"; then
+	      $ECHO "*** Warning: Linking the executable $output against the loadable module"
+	    else
+	      $ECHO "*** Warning: Linking the shared library $output against the loadable module"
+	    fi
+	    $ECHO "*** $linklib is not portable!"
+	  fi
+	  if test lib = "$linkmode" &&
+	     test yes = "$hardcode_into_libs"; then
+	    # Hardcode the library path.
+	    # Skip directories that are in the system default run-time
+	    # search path.
+	    case " $sys_lib_dlsearch_path " in
+	    *" $absdir "*) ;;
+	    *)
+	      case "$compile_rpath " in
+	      *" $absdir "*) ;;
+	      *) func_append compile_rpath " $absdir" ;;
+	      esac
+	      ;;
+	    esac
+	    case " $sys_lib_dlsearch_path " in
+	    *" $libdir "*) ;;
+	    *)
+	      case "$finalize_rpath " in
+	      *" $libdir "*) ;;
+	      *) func_append finalize_rpath " $libdir" ;;
+	      esac
+	      ;;
+	    esac
+	  fi
+
+	  if test -n "$old_archive_from_expsyms_cmds"; then
+	    # figure out the soname
+	    set dummy $library_names
+	    shift
+	    realname=$1
+	    shift
+	    libname=`eval "\\$ECHO \"$libname_spec\""`
+	    # use dlname if we got it. it's perfectly good, no?
+	    if test -n "$dlname"; then
+	      soname=$dlname
+	    elif test -n "$soname_spec"; then
+	      # bleh windows
+	      case $host in
+	      *cygwin* | mingw* | *cegcc* | *os2*)
+	        func_arith $current - $age
+		major=$func_arith_result
+		versuffix=-$major
+		;;
+	      esac
+	      eval soname=\"$soname_spec\"
+	    else
+	      soname=$realname
+	    fi
+
+	    # Make a new name for the extract_expsyms_cmds to use
+	    soroot=$soname
+	    func_basename "$soroot"
+	    soname=$func_basename_result
+	    func_stripname 'lib' '.dll' "$soname"
+	    newlib=libimp-$func_stripname_result.a
+
+	    # If the library has no export list, then create one now
+	    if test -f "$output_objdir/$soname-def"; then :
+	    else
+	      func_verbose "extracting exported symbol list from '$soname'"
+	      func_execute_cmds "$extract_expsyms_cmds" 'exit $?'
+	    fi
+
+	    # Create $newlib
+	    if test -f "$output_objdir/$newlib"; then :; else
+	      func_verbose "generating import library for '$soname'"
+	      func_execute_cmds "$old_archive_from_expsyms_cmds" 'exit $?'
+	    fi
+	    # make sure the library variables are pointing to the new library
+	    dir=$output_objdir
+	    linklib=$newlib
+	  fi # test -n "$old_archive_from_expsyms_cmds"
+
+	  if test prog = "$linkmode" || test relink != "$opt_mode"; then
+	    add_shlibpath=
+	    add_dir=
+	    add=
+	    lib_linked=yes
+	    case $hardcode_action in
+	    immediate | unsupported)
+	      if test no = "$hardcode_direct"; then
+		add=$dir/$linklib
+		case $host in
+		  *-*-sco3.2v5.0.[024]*) add_dir=-L$dir ;;
+		  *-*-sysv4*uw2*) add_dir=-L$dir ;;
+		  *-*-sysv5OpenUNIX* | *-*-sysv5UnixWare7.[01].[10]* | \
+		    *-*-unixware7*) add_dir=-L$dir ;;
+		  *-*-darwin* )
+		    # if the lib is a (non-dlopened) module then we cannot
+		    # link against it, someone is ignoring the earlier warnings
+		    if /usr/bin/file -L $add 2> /dev/null |
+			 $GREP ": [^:]* bundle" >/dev/null; then
+		      if test "X$dlopenmodule" != "X$lib"; then
+			$ECHO "*** Warning: lib $linklib is a module, not a shared library"
+			if test -z "$old_library"; then
+			  echo
+			  echo "*** And there doesn't seem to be a static archive available"
+			  echo "*** The link will probably fail, sorry"
+			else
+			  add=$dir/$old_library
+			fi
+		      elif test -n "$old_library"; then
+			add=$dir/$old_library
+		      fi
+		    fi
+		esac
+	      elif test no = "$hardcode_minus_L"; then
+		case $host in
+		*-*-sunos*) add_shlibpath=$dir ;;
+		esac
+		add_dir=-L$dir
+		add=-l$name
+	      elif test no = "$hardcode_shlibpath_var"; then
+		add_shlibpath=$dir
+		add=-l$name
+	      else
+		lib_linked=no
+	      fi
+	      ;;
+	    relink)
+	      if test yes = "$hardcode_direct" &&
+	         test no = "$hardcode_direct_absolute"; then
+		add=$dir/$linklib
+	      elif test yes = "$hardcode_minus_L"; then
+		add_dir=-L$absdir
+		# Try looking first in the location we're being installed to.
+		if test -n "$inst_prefix_dir"; then
+		  case $libdir in
+		    [\\/]*)
+		      func_append add_dir " -L$inst_prefix_dir$libdir"
+		      ;;
+		  esac
+		fi
+		add=-l$name
+	      elif test yes = "$hardcode_shlibpath_var"; then
+		add_shlibpath=$dir
+		add=-l$name
+	      else
+		lib_linked=no
+	      fi
+	      ;;
+	    *) lib_linked=no ;;
+	    esac
+
+	    if test yes != "$lib_linked"; then
+	      func_fatal_configuration "unsupported hardcode properties"
+	    fi
+
+	    if test -n "$add_shlibpath"; then
+	      case :$compile_shlibpath: in
+	      *":$add_shlibpath:"*) ;;
+	      *) func_append compile_shlibpath "$add_shlibpath:" ;;
+	      esac
+	    fi
+	    if test prog = "$linkmode"; then
+	      test -n "$add_dir" && compile_deplibs="$add_dir $compile_deplibs"
+	      test -n "$add" && compile_deplibs="$add $compile_deplibs"
+	    else
+	      test -n "$add_dir" && deplibs="$add_dir $deplibs"
+	      test -n "$add" && deplibs="$add $deplibs"
+	      if test yes != "$hardcode_direct" &&
+		 test yes != "$hardcode_minus_L" &&
+		 test yes = "$hardcode_shlibpath_var"; then
+		case :$finalize_shlibpath: in
+		*":$libdir:"*) ;;
+		*) func_append finalize_shlibpath "$libdir:" ;;
+		esac
+	      fi
+	    fi
+	  fi
+
+	  if test prog = "$linkmode" || test relink = "$opt_mode"; then
+	    add_shlibpath=
+	    add_dir=
+	    add=
+	    # Finalize command for both is simple: just hardcode it.
+	    if test yes = "$hardcode_direct" &&
+	       test no = "$hardcode_direct_absolute"; then
+	      add=$libdir/$linklib
+	    elif test yes = "$hardcode_minus_L"; then
+	      add_dir=-L$libdir
+	      add=-l$name
+	    elif test yes = "$hardcode_shlibpath_var"; then
+	      case :$finalize_shlibpath: in
+	      *":$libdir:"*) ;;
+	      *) func_append finalize_shlibpath "$libdir:" ;;
+	      esac
+	      add=-l$name
+	    elif test yes = "$hardcode_automatic"; then
+	      if test -n "$inst_prefix_dir" &&
+		 test -f "$inst_prefix_dir$libdir/$linklib"; then
+		add=$inst_prefix_dir$libdir/$linklib
+	      else
+		add=$libdir/$linklib
+	      fi
+	    else
+	      # We cannot seem to hardcode it, guess we'll fake it.
+	      add_dir=-L$libdir
+	      # Try looking first in the location we're being installed to.
+	      if test -n "$inst_prefix_dir"; then
+		case $libdir in
+		  [\\/]*)
+		    func_append add_dir " -L$inst_prefix_dir$libdir"
+		    ;;
+		esac
+	      fi
+	      add=-l$name
+	    fi
+
+	    if test prog = "$linkmode"; then
+	      test -n "$add_dir" && finalize_deplibs="$add_dir $finalize_deplibs"
+	      test -n "$add" && finalize_deplibs="$add $finalize_deplibs"
+	    else
+	      test -n "$add_dir" && deplibs="$add_dir $deplibs"
+	      test -n "$add" && deplibs="$add $deplibs"
+	    fi
+	  fi
+	elif test prog = "$linkmode"; then
+	  # Here we assume that one of hardcode_direct or hardcode_minus_L
+	  # is not unsupported.  This is valid on all known static and
+	  # shared platforms.
+	  if test unsupported != "$hardcode_direct"; then
+	    test -n "$old_library" && linklib=$old_library
+	    compile_deplibs="$dir/$linklib $compile_deplibs"
+	    finalize_deplibs="$dir/$linklib $finalize_deplibs"
+	  else
+	    compile_deplibs="-l$name -L$dir $compile_deplibs"
+	    finalize_deplibs="-l$name -L$dir $finalize_deplibs"
+	  fi
+	elif test yes = "$build_libtool_libs"; then
+	  # Not a shared library
+	  if test pass_all != "$deplibs_check_method"; then
+	    # We're trying link a shared library against a static one
+	    # but the system doesn't support it.
+
+	    # Just print a warning and add the library to dependency_libs so
+	    # that the program can be linked against the static library.
+	    echo
+	    $ECHO "*** Warning: This system cannot link to static lib archive $lib."
+	    echo "*** I have the capability to make that library automatically link in when"
+	    echo "*** you link to this library.  But I can only do this if you have a"
+	    echo "*** shared version of the library, which you do not appear to have."
+	    if test yes = "$module"; then
+	      echo "*** But as you try to build a module library, libtool will still create "
+	      echo "*** a static module, that should work as long as the dlopening application"
+	      echo "*** is linked with the -dlopen flag to resolve symbols at runtime."
+	      if test -z "$global_symbol_pipe"; then
+		echo
+		echo "*** However, this would only work if libtool was able to extract symbol"
+		echo "*** lists from a program, using 'nm' or equivalent, but libtool could"
+		echo "*** not find such a program.  So, this module is probably useless."
+		echo "*** 'nm' from GNU binutils and a full rebuild may help."
+	      fi
+	      if test no = "$build_old_libs"; then
+		build_libtool_libs=module
+		build_old_libs=yes
+	      else
+		build_libtool_libs=no
+	      fi
+	    fi
+	  else
+	    deplibs="$dir/$old_library $deplibs"
+	    link_static=yes
+	  fi
+	fi # link shared/static library?
+
+	if test lib = "$linkmode"; then
+	  if test -n "$dependency_libs" &&
+	     { test yes != "$hardcode_into_libs" ||
+	       test yes = "$build_old_libs" ||
+	       test yes = "$link_static"; }; then
+	    # Extract -R from dependency_libs
+	    temp_deplibs=
+	    for libdir in $dependency_libs; do
+	      case $libdir in
+	      -R*) func_stripname '-R' '' "$libdir"
+	           temp_xrpath=$func_stripname_result
+		   case " $xrpath " in
+		   *" $temp_xrpath "*) ;;
+		   *) func_append xrpath " $temp_xrpath";;
+		   esac;;
+	      *) func_append temp_deplibs " $libdir";;
+	      esac
+	    done
+	    dependency_libs=$temp_deplibs
+	  fi
+
+	  func_append newlib_search_path " $absdir"
+	  # Link against this library
+	  test no = "$link_static" && newdependency_libs="$abs_ladir/$laname $newdependency_libs"
+	  # ... and its dependency_libs
+	  tmp_libs=
+	  for deplib in $dependency_libs; do
+	    newdependency_libs="$deplib $newdependency_libs"
+	    case $deplib in
+              -L*) func_stripname '-L' '' "$deplib"
+                   func_resolve_sysroot "$func_stripname_result";;
+              *) func_resolve_sysroot "$deplib" ;;
+            esac
+	    if $opt_preserve_dup_deps; then
+	      case "$tmp_libs " in
+	      *" $func_resolve_sysroot_result "*)
+                func_append specialdeplibs " $func_resolve_sysroot_result" ;;
+	      esac
+	    fi
+	    func_append tmp_libs " $func_resolve_sysroot_result"
+	  done
+
+	  if test no != "$link_all_deplibs"; then
+	    # Add the search paths of all dependency libraries
+	    for deplib in $dependency_libs; do
+	      path=
+	      case $deplib in
+	      -L*) path=$deplib ;;
+	      *.la)
+	        func_resolve_sysroot "$deplib"
+	        deplib=$func_resolve_sysroot_result
+	        func_dirname "$deplib" "" "."
+		dir=$func_dirname_result
+		# We need an absolute path.
+		case $dir in
+		[\\/]* | [A-Za-z]:[\\/]*) absdir=$dir ;;
+		*)
+		  absdir=`cd "$dir" && pwd`
+		  if test -z "$absdir"; then
+		    func_warning "cannot determine absolute directory name of '$dir'"
+		    absdir=$dir
+		  fi
+		  ;;
+		esac
+		if $GREP "^installed=no" $deplib > /dev/null; then
+		case $host in
+		*-*-darwin*)
+		  depdepl=
+		  eval deplibrary_names=`$SED -n -e 's/^library_names=\(.*\)$/\1/p' $deplib`
+		  if test -n "$deplibrary_names"; then
+		    for tmp in $deplibrary_names; do
+		      depdepl=$tmp
+		    done
+		    if test -f "$absdir/$objdir/$depdepl"; then
+		      depdepl=$absdir/$objdir/$depdepl
+		      darwin_install_name=`$OTOOL -L $depdepl | awk '{if (NR == 2) {print $1;exit}}'`
+                      if test -z "$darwin_install_name"; then
+                          darwin_install_name=`$OTOOL64 -L $depdepl  | awk '{if (NR == 2) {print $1;exit}}'`
+                      fi
+		      func_append compiler_flags " $wl-dylib_file $wl$darwin_install_name:$depdepl"
+		      func_append linker_flags " -dylib_file $darwin_install_name:$depdepl"
+		      path=
+		    fi
+		  fi
+		  ;;
+		*)
+		  path=-L$absdir/$objdir
+		  ;;
+		esac
+		else
+		  eval libdir=`$SED -n -e 's/^libdir=\(.*\)$/\1/p' $deplib`
+		  test -z "$libdir" && \
+		    func_fatal_error "'$deplib' is not a valid libtool archive"
+		  test "$absdir" != "$libdir" && \
+		    func_warning "'$deplib' seems to be moved"
+
+		  path=-L$absdir
+		fi
+		;;
+	      esac
+	      case " $deplibs " in
+	      *" $path "*) ;;
+	      *) deplibs="$path $deplibs" ;;
+	      esac
+	    done
+	  fi # link_all_deplibs != no
+	fi # linkmode = lib
+      done # for deplib in $libs
+      if test link = "$pass"; then
+	if test prog = "$linkmode"; then
+	  compile_deplibs="$new_inherited_linker_flags $compile_deplibs"
+	  finalize_deplibs="$new_inherited_linker_flags $finalize_deplibs"
+	else
+	  compiler_flags="$compiler_flags "`$ECHO " $new_inherited_linker_flags" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	fi
+      fi
+      dependency_libs=$newdependency_libs
+      if test dlpreopen = "$pass"; then
+	# Link the dlpreopened libraries before other libraries
+	for deplib in $save_deplibs; do
+	  deplibs="$deplib $deplibs"
+	done
+      fi
+      if test dlopen != "$pass"; then
+	test conv = "$pass" || {
+	  # Make sure lib_search_path contains only unique directories.
+	  lib_search_path=
+	  for dir in $newlib_search_path; do
+	    case "$lib_search_path " in
+	    *" $dir "*) ;;
+	    *) func_append lib_search_path " $dir" ;;
+	    esac
+	  done
+	  newlib_search_path=
+	}
+
+	if test prog,link = "$linkmode,$pass"; then
+	  vars="compile_deplibs finalize_deplibs"
+	else
+	  vars=deplibs
+	fi
+	for var in $vars dependency_libs; do
+	  # Add libraries to $var in reverse order
+	  eval tmp_libs=\"\$$var\"
+	  new_libs=
+	  for deplib in $tmp_libs; do
+	    # FIXME: Pedantically, this is the right thing to do, so
+	    #        that some nasty dependency loop isn't accidentally
+	    #        broken:
+	    #new_libs="$deplib $new_libs"
+	    # Pragmatically, this seems to cause very few problems in
+	    # practice:
+	    case $deplib in
+	    -L*) new_libs="$deplib $new_libs" ;;
+	    -R*) ;;
+	    *)
+	      # And here is the reason: when a library appears more
+	      # than once as an explicit dependence of a library, or
+	      # is implicitly linked in more than once by the
+	      # compiler, it is considered special, and multiple
+	      # occurrences thereof are not removed.  Compare this
+	      # with having the same library being listed as a
+	      # dependency of multiple other libraries: in this case,
+	      # we know (pedantically, we assume) the library does not
+	      # need to be listed more than once, so we keep only the
+	      # last copy.  This is not always right, but it is rare
+	      # enough that we require users that really mean to play
+	      # such unportable linking tricks to link the library
+	      # using -Wl,-lname, so that libtool does not consider it
+	      # for duplicate removal.
+	      case " $specialdeplibs " in
+	      *" $deplib "*) new_libs="$deplib $new_libs" ;;
+	      *)
+		case " $new_libs " in
+		*" $deplib "*) ;;
+		*) new_libs="$deplib $new_libs" ;;
+		esac
+		;;
+	      esac
+	      ;;
+	    esac
+	  done
+	  tmp_libs=
+	  for deplib in $new_libs; do
+	    case $deplib in
+	    -L*)
+	      case " $tmp_libs " in
+	      *" $deplib "*) ;;
+	      *) func_append tmp_libs " $deplib" ;;
+	      esac
+	      ;;
+	    *) func_append tmp_libs " $deplib" ;;
+	    esac
+	  done
+	  eval $var=\"$tmp_libs\"
+	done # for var
+      fi
+
+      # Add Sun CC postdeps if required:
+      test CXX = "$tagname" && {
+        case $host_os in
+        linux*)
+          case `$CC -V 2>&1 | $SED 5q` in
+          *Sun\ C*) # Sun C++ 5.9
+            func_suncc_cstd_abi
+
+            if test no != "$suncc_use_cstd_abi"; then
+              func_append postdeps ' -library=Cstd -library=Crun'
+            fi
+            ;;
+          esac
+          ;;
+
+        solaris*)
+          func_cc_basename "$CC"
+          case $func_cc_basename_result in
+          CC* | sunCC*)
+            func_suncc_cstd_abi
+
+            if test no != "$suncc_use_cstd_abi"; then
+              func_append postdeps ' -library=Cstd -library=Crun'
+            fi
+            ;;
+          esac
+          ;;
+        esac
+      }
+
+      # Last step: remove runtime libs from dependency_libs
+      # (they stay in deplibs)
+      tmp_libs=
+      for i in $dependency_libs; do
+	case " $predeps $postdeps $compiler_lib_search_path " in
+	*" $i "*)
+	  i=
+	  ;;
+	esac
+	if test -n "$i"; then
+	  func_append tmp_libs " $i"
+	fi
+      done
+      dependency_libs=$tmp_libs
+    done # for pass
+    if test prog = "$linkmode"; then
+      dlfiles=$newdlfiles
+    fi
+    if test prog = "$linkmode" || test lib = "$linkmode"; then
+      dlprefiles=$newdlprefiles
+    fi
+
+    case $linkmode in
+    oldlib)
+      if test -n "$dlfiles$dlprefiles" || test no != "$dlself"; then
+	func_warning "'-dlopen' is ignored for archives"
+      fi
+
+      case " $deplibs" in
+      *\ -l* | *\ -L*)
+	func_warning "'-l' and '-L' are ignored for archives" ;;
+      esac
+
+      test -n "$rpath" && \
+	func_warning "'-rpath' is ignored for archives"
+
+      test -n "$xrpath" && \
+	func_warning "'-R' is ignored for archives"
+
+      test -n "$vinfo" && \
+	func_warning "'-version-info/-version-number' is ignored for archives"
+
+      test -n "$release" && \
+	func_warning "'-release' is ignored for archives"
+
+      test -n "$export_symbols$export_symbols_regex" && \
+	func_warning "'-export-symbols' is ignored for archives"
+
+      # Now set the variables for building old libraries.
+      build_libtool_libs=no
+      oldlibs=$output
+      func_append objs "$old_deplibs"
+      ;;
+
+    lib)
+      # Make sure we only generate libraries of the form 'libNAME.la'.
+      case $outputname in
+      lib*)
+	func_stripname 'lib' '.la' "$outputname"
+	name=$func_stripname_result
+	eval shared_ext=\"$shrext_cmds\"
+	eval libname=\"$libname_spec\"
+	;;
+      *)
+	test no = "$module" \
+	  && func_fatal_help "libtool library '$output' must begin with 'lib'"
+
+	if test no != "$need_lib_prefix"; then
+	  # Add the "lib" prefix for modules if required
+	  func_stripname '' '.la' "$outputname"
+	  name=$func_stripname_result
+	  eval shared_ext=\"$shrext_cmds\"
+	  eval libname=\"$libname_spec\"
+	else
+	  func_stripname '' '.la' "$outputname"
+	  libname=$func_stripname_result
+	fi
+	;;
+      esac
+
+      if test -n "$objs"; then
+	if test pass_all != "$deplibs_check_method"; then
+	  func_fatal_error "cannot build libtool library '$output' from non-libtool objects on this host:$objs"
+	else
+	  echo
+	  $ECHO "*** Warning: Linking the shared library $output against the non-libtool"
+	  $ECHO "*** objects $objs is not portable!"
+	  func_append libobjs " $objs"
+	fi
+      fi
+
+      test no = "$dlself" \
+	|| func_warning "'-dlopen self' is ignored for libtool libraries"
+
+      set dummy $rpath
+      shift
+      test 1 -lt "$#" \
+	&& func_warning "ignoring multiple '-rpath's for a libtool library"
+
+      install_libdir=$1
+
+      oldlibs=
+      if test -z "$rpath"; then
+	if test yes = "$build_libtool_libs"; then
+	  # Building a libtool convenience library.
+	  # Some compilers have problems with a '.al' extension so
+	  # convenience libraries should have the same extension an
+	  # archive normally would.
+	  oldlibs="$output_objdir/$libname.$libext $oldlibs"
+	  build_libtool_libs=convenience
+	  build_old_libs=yes
+	fi
+
+	test -n "$vinfo" && \
+	  func_warning "'-version-info/-version-number' is ignored for convenience libraries"
+
+	test -n "$release" && \
+	  func_warning "'-release' is ignored for convenience libraries"
+      else
+
+	# Parse the version information argument.
+	save_ifs=$IFS; IFS=:
+	set dummy $vinfo 0 0 0
+	shift
+	IFS=$save_ifs
+
+	test -n "$7" && \
+	  func_fatal_help "too many parameters to '-version-info'"
+
+	# convert absolute version numbers to libtool ages
+	# this retains compatibility with .la files and attempts
+	# to make the code below a bit more comprehensible
+
+	case $vinfo_number in
+	yes)
+	  number_major=$1
+	  number_minor=$2
+	  number_revision=$3
+	  #
+	  # There are really only two kinds -- those that
+	  # use the current revision as the major version
+	  # and those that subtract age and use age as
+	  # a minor version.  But, then there is irix
+	  # that has an extra 1 added just for fun
+	  #
+	  case $version_type in
+	  # correct linux to gnu/linux during the next big refactor
+	  darwin|freebsd-elf|linux|midnightbsd-elf|osf|windows|none)
+	    func_arith $number_major + $number_minor
+	    current=$func_arith_result
+	    age=$number_minor
+	    revision=$number_revision
+	    ;;
+	  freebsd-aout|qnx|sunos)
+	    current=$number_major
+	    revision=$number_minor
+	    age=0
+	    ;;
+	  irix|nonstopux)
+	    func_arith $number_major + $number_minor
+	    current=$func_arith_result
+	    age=$number_minor
+	    revision=$number_minor
+	    lt_irix_increment=no
+	    ;;
+	  esac
+	  ;;
+	no)
+	  current=$1
+	  revision=$2
+	  age=$3
+	  ;;
+	esac
+
+	# Check that each of the things are valid numbers.
+	case $current in
+	0|[1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9][0-9][0-9]) ;;
+	*)
+	  func_error "CURRENT '$current' must be a nonnegative integer"
+	  func_fatal_error "'$vinfo' is not valid version information"
+	  ;;
+	esac
+
+	case $revision in
+	0|[1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9][0-9][0-9]) ;;
+	*)
+	  func_error "REVISION '$revision' must be a nonnegative integer"
+	  func_fatal_error "'$vinfo' is not valid version information"
+	  ;;
+	esac
+
+	case $age in
+	0|[1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|[1-9][0-9][0-9][0-9][0-9]) ;;
+	*)
+	  func_error "AGE '$age' must be a nonnegative integer"
+	  func_fatal_error "'$vinfo' is not valid version information"
+	  ;;
+	esac
+
+	if test "$age" -gt "$current"; then
+	  func_error "AGE '$age' is greater than the current interface number '$current'"
+	  func_fatal_error "'$vinfo' is not valid version information"
+	fi
+
+	# Calculate the version variables.
+	major=
+	versuffix=
+	verstring=
+	case $version_type in
+	none) ;;
+
+	darwin)
+	  # Like Linux, but with the current version available in
+	  # verstring for coding it into the library header
+	  func_arith $current - $age
+	  major=.$func_arith_result
+	  versuffix=$major.$age.$revision
+	  # Darwin ld doesn't like 0 for these options...
+	  func_arith $current + 1
+	  minor_current=$func_arith_result
+	  xlcverstring="$wl-compatibility_version $wl$minor_current $wl-current_version $wl$minor_current.$revision"
+	  verstring="-compatibility_version $minor_current -current_version $minor_current.$revision"
+          # On Darwin other compilers
+          case $CC in
+              nagfor*)
+                  verstring="$wl-compatibility_version $wl$minor_current $wl-current_version $wl$minor_current.$revision"
+                  ;;
+              *)
+                  verstring="-compatibility_version $minor_current -current_version $minor_current.$revision"
+                  ;;
+          esac
+	  ;;
+
+	freebsd-aout)
+	  major=.$current
+	  versuffix=.$current.$revision
+	  ;;
+
+	freebsd-elf | midnightbsd-elf)
+	  func_arith $current - $age
+	  major=.$func_arith_result
+	  versuffix=$major.$age.$revision
+	  ;;
+
+	irix | nonstopux)
+	  if test no = "$lt_irix_increment"; then
+	    func_arith $current - $age
+	  else
+	    func_arith $current - $age + 1
+	  fi
+	  major=$func_arith_result
+
+	  case $version_type in
+	    nonstopux) verstring_prefix=nonstopux ;;
+	    *)         verstring_prefix=sgi ;;
+	  esac
+	  verstring=$verstring_prefix$major.$revision
+
+	  # Add in all the interfaces that we are compatible with.
+	  loop=$revision
+	  while test 0 -ne "$loop"; do
+	    func_arith $revision - $loop
+	    iface=$func_arith_result
+	    func_arith $loop - 1
+	    loop=$func_arith_result
+	    verstring=$verstring_prefix$major.$iface:$verstring
+	  done
+
+	  # Before this point, $major must not contain '.'.
+	  major=.$major
+	  versuffix=$major.$revision
+	  ;;
+
+	linux) # correct to gnu/linux during the next big refactor
+	  func_arith $current - $age
+	  major=.$func_arith_result
+	  versuffix=$major.$age.$revision
+	  ;;
+
+	osf)
+	  func_arith $current - $age
+	  major=.$func_arith_result
+	  versuffix=.$current.$age.$revision
+	  verstring=$current.$age.$revision
+
+	  # Add in all the interfaces that we are compatible with.
+	  loop=$age
+	  while test 0 -ne "$loop"; do
+	    func_arith $current - $loop
+	    iface=$func_arith_result
+	    func_arith $loop - 1
+	    loop=$func_arith_result
+	    verstring=$verstring:$iface.0
+	  done
+
+	  # Make executables depend on our current version.
+	  func_append verstring ":$current.0"
+	  ;;
+
+	qnx)
+	  major=.$current
+	  versuffix=.$current
+	  ;;
+
+	sco)
+	  major=.$current
+	  versuffix=.$current
+	  ;;
+
+	sunos)
+	  major=.$current
+	  versuffix=.$current.$revision
+	  ;;
+
+	windows)
+	  # Use '-' rather than '.', since we only want one
+	  # extension on DOS 8.3 file systems.
+	  func_arith $current - $age
+	  major=$func_arith_result
+	  versuffix=-$major
+	  ;;
+
+	*)
+	  func_fatal_configuration "unknown library version type '$version_type'"
+	  ;;
+	esac
+
+	# Clear the version info if we defaulted, and they specified a release.
+	if test -z "$vinfo" && test -n "$release"; then
+	  major=
+	  case $version_type in
+	  darwin)
+	    # we can't check for "0.0" in archive_cmds due to quoting
+	    # problems, so we reset it completely
+	    verstring=
+	    ;;
+	  *)
+	    verstring=0.0
+	    ;;
+	  esac
+	  if test no = "$need_version"; then
+	    versuffix=
+	  else
+	    versuffix=.0.0
+	  fi
+	fi
+
+	# Remove version info from name if versioning should be avoided
+	if test yes,no = "$avoid_version,$need_version"; then
+	  major=
+	  versuffix=
+	  verstring=
+	fi
+
+	# Check to see if the archive will have undefined symbols.
+	if test yes = "$allow_undefined"; then
+	  if test unsupported = "$allow_undefined_flag"; then
+	    if test yes = "$build_old_libs"; then
+	      func_warning "undefined symbols not allowed in $host shared libraries; building static only"
+	      build_libtool_libs=no
+	    else
+	      func_fatal_error "can't build $host shared library unless -no-undefined is specified"
+	    fi
+	  fi
+	else
+	  # Don't allow undefined symbols.
+	  allow_undefined_flag=$no_undefined_flag
+	fi
+
+      fi
+
+      func_generate_dlsyms "$libname" "$libname" :
+      func_append libobjs " $symfileobj"
+      test " " = "$libobjs" && libobjs=
+
+      if test relink != "$opt_mode"; then
+	# Remove our outputs, but don't remove object files since they
+	# may have been created when compiling PIC objects.
+	removelist=
+	tempremovelist=`$ECHO "$output_objdir/*"`
+	for p in $tempremovelist; do
+	  case $p in
+	    *.$objext | *.gcno)
+	       ;;
+	    $output_objdir/$outputname | $output_objdir/$libname.* | $output_objdir/$libname$release.*)
+	       if test -n "$precious_files_regex"; then
+		 if $ECHO "$p" | $EGREP -e "$precious_files_regex" >/dev/null 2>&1
+		 then
+		   continue
+		 fi
+	       fi
+	       func_append removelist " $p"
+	       ;;
+	    *) ;;
+	  esac
+	done
+	test -n "$removelist" && \
+	  func_show_eval "${RM}r \$removelist"
+      fi
+
+      # Now set the variables for building old libraries.
+      if test yes = "$build_old_libs" && test convenience != "$build_libtool_libs"; then
+	func_append oldlibs " $output_objdir/$libname.$libext"
+
+	# Transform .lo files to .o files.
+	oldobjs="$objs "`$ECHO "$libobjs" | $SP2NL | $SED "/\.$libext$/d; $lo2o" | $NL2SP`
+      fi
+
+      # Eliminate all temporary directories.
+      #for path in $notinst_path; do
+      #	lib_search_path=`$ECHO "$lib_search_path " | $SED "s% $path % %g"`
+      #	deplibs=`$ECHO "$deplibs " | $SED "s% -L$path % %g"`
+      #	dependency_libs=`$ECHO "$dependency_libs " | $SED "s% -L$path % %g"`
+      #done
+
+      if test -n "$xrpath"; then
+	# If the user specified any rpath flags, then add them.
+	temp_xrpath=
+	for libdir in $xrpath; do
+	  func_replace_sysroot "$libdir"
+	  func_append temp_xrpath " -R$func_replace_sysroot_result"
+	  case "$finalize_rpath " in
+	  *" $libdir "*) ;;
+	  *) func_append finalize_rpath " $libdir" ;;
+	  esac
+	done
+	if test yes != "$hardcode_into_libs" || test yes = "$build_old_libs"; then
+	  dependency_libs="$temp_xrpath $dependency_libs"
+	fi
+      fi
+
+      # Make sure dlfiles contains only unique files that won't be dlpreopened
+      old_dlfiles=$dlfiles
+      dlfiles=
+      for lib in $old_dlfiles; do
+	case " $dlprefiles $dlfiles " in
+	*" $lib "*) ;;
+	*) func_append dlfiles " $lib" ;;
+	esac
+      done
+
+      # Make sure dlprefiles contains only unique files
+      old_dlprefiles=$dlprefiles
+      dlprefiles=
+      for lib in $old_dlprefiles; do
+	case "$dlprefiles " in
+	*" $lib "*) ;;
+	*) func_append dlprefiles " $lib" ;;
+	esac
+      done
+
+      if test yes = "$build_libtool_libs"; then
+	if test -n "$rpath"; then
+	  case $host in
+	  *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-beos* | *-cegcc* | *-*-haiku*)
+	    # these systems don't actually have a c library (as such)!
+	    ;;
+	  *-*-rhapsody* | *-*-darwin1.[012])
+	    # Rhapsody C library is in the System framework
+	    func_append deplibs " System.ltframework"
+	    ;;
+	  *-*-netbsd*)
+	    # Don't link with libc until the a.out ld.so is fixed.
+	    ;;
+	  *-*-openbsd* | *-*-freebsd* | *-*-dragonfly* | *-*-midnightbsd*)
+	    # Do not include libc due to us having libc/libc_r.
+	    ;;
+	  *-*-sco3.2v5* | *-*-sco5v6*)
+	    # Causes problems with __ctype
+	    ;;
+	  *-*-sysv4.2uw2* | *-*-sysv5* | *-*-unixware* | *-*-OpenUNIX*)
+	    # Compiler inserts libc in the correct place for threads to work
+	    ;;
+	  *)
+	    # Add libc to deplibs on all other systems if necessary.
+	    if test yes = "$build_libtool_need_lc"; then
+	      func_append deplibs " -lc"
+	    fi
+	    ;;
+	  esac
+	fi
+
+	# Transform deplibs into only deplibs that can be linked in shared.
+	name_save=$name
+	libname_save=$libname
+	release_save=$release
+	versuffix_save=$versuffix
+	major_save=$major
+	# I'm not sure if I'm treating the release correctly.  I think
+	# release should show up in the -l (ie -lgmp5) so we don't want to
+	# add it in twice.  Is that correct?
+	release=
+	versuffix=
+	major=
+	newdeplibs=
+	droppeddeps=no
+	case $deplibs_check_method in
+	pass_all)
+	  # Don't check for shared/static.  Everything works.
+	  # This might be a little naive.  We might want to check
+	  # whether the library exists or not.  But this is on
+	  # osf3 & osf4 and I'm not really sure... Just
+	  # implementing what was already the behavior.
+	  newdeplibs=$deplibs
+	  ;;
+	test_compile)
+	  # This code stresses the "libraries are programs" paradigm to its
+	  # limits. Maybe even breaks it.  We compile a program, linking it
+	  # against the deplibs as a proxy for the library.  Then we can check
+	  # whether they linked in statically or dynamically with ldd.
+	  $opt_dry_run || $RM conftest.c
+	  cat > conftest.c <<EOF
+	  int main() { return 0; }
+EOF
+	  $opt_dry_run || $RM conftest
+	  if $LTCC $LTCFLAGS -o conftest conftest.c $deplibs; then
+	    ldd_output=`ldd conftest`
+	    for i in $deplibs; do
+	      case $i in
+	      -l*)
+		func_stripname -l '' "$i"
+		name=$func_stripname_result
+		if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+		  case " $predeps $postdeps " in
+		  *" $i "*)
+		    func_append newdeplibs " $i"
+		    i=
+		    ;;
+		  esac
+		fi
+		if test -n "$i"; then
+		  libname=`eval "\\$ECHO \"$libname_spec\""`
+		  deplib_matches=`eval "\\$ECHO \"$library_names_spec\""`
+		  set dummy $deplib_matches; shift
+		  deplib_match=$1
+		  if test `expr "$ldd_output" : ".*$deplib_match"` -ne 0; then
+		    func_append newdeplibs " $i"
+		  else
+		    droppeddeps=yes
+		    echo
+		    $ECHO "*** Warning: dynamic linker does not accept needed library $i."
+		    echo "*** I have the capability to make that library automatically link in when"
+		    echo "*** you link to this library.  But I can only do this if you have a"
+		    echo "*** shared version of the library, which I believe you do not have"
+		    echo "*** because a test_compile did reveal that the linker did not use it for"
+		    echo "*** its dynamic dependency list that programs get resolved with at runtime."
+		  fi
+		fi
+		;;
+	      *)
+		func_append newdeplibs " $i"
+		;;
+	      esac
+	    done
+	  else
+	    # Error occurred in the first compile.  Let's try to salvage
+	    # the situation: Compile a separate program for each library.
+	    for i in $deplibs; do
+	      case $i in
+	      -l*)
+		func_stripname -l '' "$i"
+		name=$func_stripname_result
+		$opt_dry_run || $RM conftest
+		if $LTCC $LTCFLAGS -o conftest conftest.c $i; then
+		  ldd_output=`ldd conftest`
+		  if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+		    case " $predeps $postdeps " in
+		    *" $i "*)
+		      func_append newdeplibs " $i"
+		      i=
+		      ;;
+		    esac
+		  fi
+		  if test -n "$i"; then
+		    libname=`eval "\\$ECHO \"$libname_spec\""`
+		    deplib_matches=`eval "\\$ECHO \"$library_names_spec\""`
+		    set dummy $deplib_matches; shift
+		    deplib_match=$1
+		    if test `expr "$ldd_output" : ".*$deplib_match"` -ne 0; then
+		      func_append newdeplibs " $i"
+		    else
+		      droppeddeps=yes
+		      echo
+		      $ECHO "*** Warning: dynamic linker does not accept needed library $i."
+		      echo "*** I have the capability to make that library automatically link in when"
+		      echo "*** you link to this library.  But I can only do this if you have a"
+		      echo "*** shared version of the library, which you do not appear to have"
+		      echo "*** because a test_compile did reveal that the linker did not use this one"
+		      echo "*** as a dynamic dependency that programs can get resolved with at runtime."
+		    fi
+		  fi
+		else
+		  droppeddeps=yes
+		  echo
+		  $ECHO "*** Warning!  Library $i is needed by this library but I was not able to"
+		  echo "*** make it link in!  You will probably need to install it or some"
+		  echo "*** library that it depends on before this library will be fully"
+		  echo "*** functional.  Installing it before continuing would be even better."
+		fi
+		;;
+	      *)
+		func_append newdeplibs " $i"
+		;;
+	      esac
+	    done
+	  fi
+	  ;;
+	file_magic*)
+	  set dummy $deplibs_check_method; shift
+	  file_magic_regex=`expr "$deplibs_check_method" : "$1 \(.*\)"`
+	  for a_deplib in $deplibs; do
+	    case $a_deplib in
+	    -l*)
+	      func_stripname -l '' "$a_deplib"
+	      name=$func_stripname_result
+	      if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+		case " $predeps $postdeps " in
+		*" $a_deplib "*)
+		  func_append newdeplibs " $a_deplib"
+		  a_deplib=
+		  ;;
+		esac
+	      fi
+	      if test -n "$a_deplib"; then
+		libname=`eval "\\$ECHO \"$libname_spec\""`
+		if test -n "$file_magic_glob"; then
+		  libnameglob=`func_echo_all "$libname" | $SED -e $file_magic_glob`
+		else
+		  libnameglob=$libname
+		fi
+		test yes = "$want_nocaseglob" && nocaseglob=`shopt -p nocaseglob`
+		for i in $lib_search_path $sys_lib_search_path $shlib_search_path; do
+		  if test yes = "$want_nocaseglob"; then
+		    shopt -s nocaseglob
+		    potential_libs=`ls $i/$libnameglob[.-]* 2>/dev/null`
+		    $nocaseglob
+		  else
+		    potential_libs=`ls $i/$libnameglob[.-]* 2>/dev/null`
+		  fi
+		  for potent_lib in $potential_libs; do
+		      # Follow soft links.
+		      if ls -lLd "$potent_lib" 2>/dev/null |
+			 $GREP " -> " >/dev/null; then
+			continue
+		      fi
+		      # The statement above tries to avoid entering an
+		      # endless loop below, in case of cyclic links.
+		      # We might still enter an endless loop, since a link
+		      # loop can be closed while we follow links,
+		      # but so what?
+		      potlib=$potent_lib
+		      while test -h "$potlib" 2>/dev/null; do
+			potliblink=`ls -ld $potlib | $SED 's/.* -> //'`
+			case $potliblink in
+			[\\/]* | [A-Za-z]:[\\/]*) potlib=$potliblink;;
+			*) potlib=`$ECHO "$potlib" | $SED 's|[^/]*$||'`"$potliblink";;
+			esac
+		      done
+		      if eval $file_magic_cmd \"\$potlib\" 2>/dev/null |
+			 $SED -e 10q |
+			 $EGREP "$file_magic_regex" > /dev/null; then
+			func_append newdeplibs " $a_deplib"
+			a_deplib=
+			break 2
+		      fi
+		  done
+		done
+	      fi
+	      if test -n "$a_deplib"; then
+		droppeddeps=yes
+		echo
+		$ECHO "*** Warning: linker path does not have real file for library $a_deplib."
+		echo "*** I have the capability to make that library automatically link in when"
+		echo "*** you link to this library.  But I can only do this if you have a"
+		echo "*** shared version of the library, which you do not appear to have"
+		echo "*** because I did check the linker path looking for a file starting"
+		if test -z "$potlib"; then
+		  $ECHO "*** with $libname but no candidates were found. (...for file magic test)"
+		else
+		  $ECHO "*** with $libname and none of the candidates passed a file format test"
+		  $ECHO "*** using a file magic. Last file checked: $potlib"
+		fi
+	      fi
+	      ;;
+	    *)
+	      # Add a -L argument.
+	      func_append newdeplibs " $a_deplib"
+	      ;;
+	    esac
+	  done # Gone through all deplibs.
+	  ;;
+	match_pattern*)
+	  set dummy $deplibs_check_method; shift
+	  match_pattern_regex=`expr "$deplibs_check_method" : "$1 \(.*\)"`
+	  for a_deplib in $deplibs; do
+	    case $a_deplib in
+	    -l*)
+	      func_stripname -l '' "$a_deplib"
+	      name=$func_stripname_result
+	      if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+		case " $predeps $postdeps " in
+		*" $a_deplib "*)
+		  func_append newdeplibs " $a_deplib"
+		  a_deplib=
+		  ;;
+		esac
+	      fi
+	      if test -n "$a_deplib"; then
+		libname=`eval "\\$ECHO \"$libname_spec\""`
+		for i in $lib_search_path $sys_lib_search_path $shlib_search_path; do
+		  potential_libs=`ls $i/$libname[.-]* 2>/dev/null`
+		  for potent_lib in $potential_libs; do
+		    potlib=$potent_lib # see symlink-check above in file_magic test
+		    if eval "\$ECHO \"$potent_lib\"" 2>/dev/null | $SED 10q | \
+		       $EGREP "$match_pattern_regex" > /dev/null; then
+		      func_append newdeplibs " $a_deplib"
+		      a_deplib=
+		      break 2
+		    fi
+		  done
+		done
+	      fi
+	      if test -n "$a_deplib"; then
+		droppeddeps=yes
+		echo
+		$ECHO "*** Warning: linker path does not have real file for library $a_deplib."
+		echo "*** I have the capability to make that library automatically link in when"
+		echo "*** you link to this library.  But I can only do this if you have a"
+		echo "*** shared version of the library, which you do not appear to have"
+		echo "*** because I did check the linker path looking for a file starting"
+		if test -z "$potlib"; then
+		  $ECHO "*** with $libname but no candidates were found. (...for regex pattern test)"
+		else
+		  $ECHO "*** with $libname and none of the candidates passed a file format test"
+		  $ECHO "*** using a regex pattern. Last file checked: $potlib"
+		fi
+	      fi
+	      ;;
+	    *)
+	      # Add a -L argument.
+	      func_append newdeplibs " $a_deplib"
+	      ;;
+	    esac
+	  done # Gone through all deplibs.
+	  ;;
+	none | unknown | *)
+	  newdeplibs=
+	  tmp_deplibs=`$ECHO " $deplibs" | $SED 's/ -lc$//; s/ -[LR][^ ]*//g'`
+	  if test yes = "$allow_libtool_libs_with_static_runtimes"; then
+	    for i in $predeps $postdeps; do
+	      # can't use Xsed below, because $i might contain '/'
+	      tmp_deplibs=`$ECHO " $tmp_deplibs" | $SED "s|$i||"`
+	    done
+	  fi
+	  case $tmp_deplibs in
+	  *[!\	\ ]*)
+	    echo
+	    if test none = "$deplibs_check_method"; then
+	      echo "*** Warning: inter-library dependencies are not supported in this platform."
+	    else
+	      echo "*** Warning: inter-library dependencies are not known to be supported."
+	    fi
+	    echo "*** All declared inter-library dependencies are being dropped."
+	    droppeddeps=yes
+	    ;;
+	  esac
+	  ;;
+	esac
+	versuffix=$versuffix_save
+	major=$major_save
+	release=$release_save
+	libname=$libname_save
+	name=$name_save
+
+	case $host in
+	*-*-rhapsody* | *-*-darwin1.[012])
+	  # On Rhapsody replace the C library with the System framework
+	  newdeplibs=`$ECHO " $newdeplibs" | $SED 's/ -lc / System.ltframework /'`
+	  ;;
+	esac
+
+	if test yes = "$droppeddeps"; then
+	  if test yes = "$module"; then
+	    echo
+	    echo "*** Warning: libtool could not satisfy all declared inter-library"
+	    $ECHO "*** dependencies of module $libname.  Therefore, libtool will create"
+	    echo "*** a static module, that should work as long as the dlopening"
+	    echo "*** application is linked with the -dlopen flag."
+	    if test -z "$global_symbol_pipe"; then
+	      echo
+	      echo "*** However, this would only work if libtool was able to extract symbol"
+	      echo "*** lists from a program, using 'nm' or equivalent, but libtool could"
+	      echo "*** not find such a program.  So, this module is probably useless."
+	      echo "*** 'nm' from GNU binutils and a full rebuild may help."
+	    fi
+	    if test no = "$build_old_libs"; then
+	      oldlibs=$output_objdir/$libname.$libext
+	      build_libtool_libs=module
+	      build_old_libs=yes
+	    else
+	      build_libtool_libs=no
+	    fi
+	  else
+	    echo "*** The inter-library dependencies that have been dropped here will be"
+	    echo "*** automatically added whenever a program is linked with this library"
+	    echo "*** or is declared to -dlopen it."
+
+	    if test no = "$allow_undefined"; then
+	      echo
+	      echo "*** Since this library must not contain undefined symbols,"
+	      echo "*** because either the platform does not support them or"
+	      echo "*** it was explicitly requested with -no-undefined,"
+	      echo "*** libtool will only create a static version of it."
+	      if test no = "$build_old_libs"; then
+		oldlibs=$output_objdir/$libname.$libext
+		build_libtool_libs=module
+		build_old_libs=yes
+	      else
+		build_libtool_libs=no
+	      fi
+	    fi
+	  fi
+	fi
+	# Done checking deplibs!
+	deplibs=$newdeplibs
+      fi
+      # Time to change all our "foo.ltframework" stuff back to "-framework foo"
+      case $host in
+	*-*-darwin*)
+	  newdeplibs=`$ECHO " $newdeplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	  new_inherited_linker_flags=`$ECHO " $new_inherited_linker_flags" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	  deplibs=`$ECHO " $deplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	  ;;
+      esac
+
+      # move library search paths that coincide with paths to not yet
+      # installed libraries to the beginning of the library search list
+      new_libs=
+      for path in $notinst_path; do
+	case " $new_libs " in
+	*" -L$path/$objdir "*) ;;
+	*)
+	  case " $deplibs " in
+	  *" -L$path/$objdir "*)
+	    func_append new_libs " -L$path/$objdir" ;;
+	  esac
+	  ;;
+	esac
+      done
+      for deplib in $deplibs; do
+	case $deplib in
+	-L*)
+	  case " $new_libs " in
+	  *" $deplib "*) ;;
+	  *) func_append new_libs " $deplib" ;;
+	  esac
+	  ;;
+	*) func_append new_libs " $deplib" ;;
+	esac
+      done
+      deplibs=$new_libs
+
+      # All the library-specific variables (install_libdir is set above).
+      library_names=
+      old_library=
+      dlname=
+
+      # Test again, we may have decided not to build it any more
+      if test yes = "$build_libtool_libs"; then
+	# Remove $wl instances when linking with ld.
+	# FIXME: should test the right _cmds variable.
+	case $archive_cmds in
+	  *\$LD\ *) wl= ;;
+        esac
+	if test yes = "$hardcode_into_libs"; then
+	  # Hardcode the library paths
+	  hardcode_libdirs=
+	  dep_rpath=
+	  rpath=$finalize_rpath
+	  test relink = "$opt_mode" || rpath=$compile_rpath$rpath
+	  for libdir in $rpath; do
+	    if test -n "$hardcode_libdir_flag_spec"; then
+	      if test -n "$hardcode_libdir_separator"; then
+		func_replace_sysroot "$libdir"
+		libdir=$func_replace_sysroot_result
+		if test -z "$hardcode_libdirs"; then
+		  hardcode_libdirs=$libdir
+		else
+		  # Just accumulate the unique libdirs.
+		  case $hardcode_libdir_separator$hardcode_libdirs$hardcode_libdir_separator in
+		  *"$hardcode_libdir_separator$libdir$hardcode_libdir_separator"*)
+		    ;;
+		  *)
+		    func_append hardcode_libdirs "$hardcode_libdir_separator$libdir"
+		    ;;
+		  esac
+		fi
+	      else
+		eval flag=\"$hardcode_libdir_flag_spec\"
+		func_append dep_rpath " $flag"
+	      fi
+	    elif test -n "$runpath_var"; then
+	      case "$perm_rpath " in
+	      *" $libdir "*) ;;
+	      *) func_append perm_rpath " $libdir" ;;
+	      esac
+	    fi
+	  done
+	  # Substitute the hardcoded libdirs into the rpath.
+	  if test -n "$hardcode_libdir_separator" &&
+	     test -n "$hardcode_libdirs"; then
+	    libdir=$hardcode_libdirs
+	    eval "dep_rpath=\"$hardcode_libdir_flag_spec\""
+	  fi
+	  if test -n "$runpath_var" && test -n "$perm_rpath"; then
+	    # We should set the runpath_var.
+	    rpath=
+	    for dir in $perm_rpath; do
+	      func_append rpath "$dir:"
+	    done
+	    eval "$runpath_var='$rpath\$$runpath_var'; export $runpath_var"
+	  fi
+	  test -n "$dep_rpath" && deplibs="$dep_rpath $deplibs"
+	fi
+
+	shlibpath=$finalize_shlibpath
+	test relink = "$opt_mode" || shlibpath=$compile_shlibpath$shlibpath
+	if test -n "$shlibpath"; then
+	  eval "$shlibpath_var='$shlibpath\$$shlibpath_var'; export $shlibpath_var"
+	fi
+
+	# Get the real and link names of the library.
+	eval shared_ext=\"$shrext_cmds\"
+	eval library_names=\"$library_names_spec\"
+	set dummy $library_names
+	shift
+	realname=$1
+	shift
+
+	if test -n "$soname_spec"; then
+	  eval soname=\"$soname_spec\"
+	else
+	  soname=$realname
+	fi
+	if test -z "$dlname"; then
+	  dlname=$soname
+	fi
+
+	lib=$output_objdir/$realname
+	linknames=
+	for link
+	do
+	  func_append linknames " $link"
+	done
+
+	# Use standard objects if they are pic
+	test -z "$pic_flag" && libobjs=`$ECHO "$libobjs" | $SP2NL | $SED "$lo2o" | $NL2SP`
+	test "X$libobjs" = "X " && libobjs=
+
+	delfiles=
+	if test -n "$export_symbols" && test -n "$include_expsyms"; then
+	  $opt_dry_run || cp "$export_symbols" "$output_objdir/$libname.uexp"
+	  export_symbols=$output_objdir/$libname.uexp
+	  func_append delfiles " $export_symbols"
+	fi
+
+	orig_export_symbols=
+	case $host_os in
+	cygwin* | mingw* | cegcc*)
+	  if test -n "$export_symbols" && test -z "$export_symbols_regex"; then
+	    # exporting using user supplied symfile
+	    func_dll_def_p "$export_symbols" || {
+	      # and it's NOT already a .def file. Must figure out
+	      # which of the given symbols are data symbols and tag
+	      # them as such. So, trigger use of export_symbols_cmds.
+	      # export_symbols gets reassigned inside the "prepare
+	      # the list of exported symbols" if statement, so the
+	      # include_expsyms logic still works.
+	      orig_export_symbols=$export_symbols
+	      export_symbols=
+	      always_export_symbols=yes
+	    }
+	  fi
+	  ;;
+	esac
+
+	# Prepare the list of exported symbols
+	if test -z "$export_symbols"; then
+	  if test yes = "$always_export_symbols" || test -n "$export_symbols_regex"; then
+	    func_verbose "generating symbol list for '$libname.la'"
+	    export_symbols=$output_objdir/$libname.exp
+	    $opt_dry_run || $RM $export_symbols
+	    cmds=$export_symbols_cmds
+	    save_ifs=$IFS; IFS='~'
+	    for cmd1 in $cmds; do
+	      IFS=$save_ifs
+	      # Take the normal branch if the nm_file_list_spec branch
+	      # doesn't work or if tool conversion is not needed.
+	      case $nm_file_list_spec~$to_tool_file_cmd in
+		*~func_convert_file_noop | *~func_convert_file_msys_to_w32 | ~*)
+		  try_normal_branch=yes
+		  eval cmd=\"$cmd1\"
+		  func_len " $cmd"
+		  len=$func_len_result
+		  ;;
+		*)
+		  try_normal_branch=no
+		  ;;
+	      esac
+	      if test yes = "$try_normal_branch" \
+		 && { test "$len" -lt "$max_cmd_len" \
+		      || test "$max_cmd_len" -le -1; }
+	      then
+		func_show_eval "$cmd" 'exit $?'
+		skipped_export=false
+	      elif test -n "$nm_file_list_spec"; then
+		func_basename "$output"
+		output_la=$func_basename_result
+		save_libobjs=$libobjs
+		save_output=$output
+		output=$output_objdir/$output_la.nm
+		func_to_tool_file "$output"
+		libobjs=$nm_file_list_spec$func_to_tool_file_result
+		func_append delfiles " $output"
+		func_verbose "creating $NM input file list: $output"
+		for obj in $save_libobjs; do
+		  func_to_tool_file "$obj"
+		  $ECHO "$func_to_tool_file_result"
+		done > "$output"
+		eval cmd=\"$cmd1\"
+		func_show_eval "$cmd" 'exit $?'
+		output=$save_output
+		libobjs=$save_libobjs
+		skipped_export=false
+	      else
+		# The command line is too long to execute in one step.
+		func_verbose "using reloadable object file for export list..."
+		skipped_export=:
+		# Break out early, otherwise skipped_export may be
+		# set to false by a later but shorter cmd.
+		break
+	      fi
+	    done
+	    IFS=$save_ifs
+	    if test -n "$export_symbols_regex" && test : != "$skipped_export"; then
+	      func_show_eval '$EGREP -e "$export_symbols_regex" "$export_symbols" > "${export_symbols}T"'
+	      func_show_eval '$MV "${export_symbols}T" "$export_symbols"'
+	    fi
+	  fi
+	fi
+
+	if test -n "$export_symbols" && test -n "$include_expsyms"; then
+	  tmp_export_symbols=$export_symbols
+	  test -n "$orig_export_symbols" && tmp_export_symbols=$orig_export_symbols
+	  $opt_dry_run || eval '$ECHO "$include_expsyms" | $SP2NL >> "$tmp_export_symbols"'
+	fi
+
+	if test : != "$skipped_export" && test -n "$orig_export_symbols"; then
+	  # The given exports_symbols file has to be filtered, so filter it.
+	  func_verbose "filter symbol list for '$libname.la' to tag DATA exports"
+	  # FIXME: $output_objdir/$libname.filter potentially contains lots of
+	  # 's' commands, which not all seds can handle. GNU sed should be fine
+	  # though. Also, the filter scales superlinearly with the number of
+	  # global variables. join(1) would be nice here, but unfortunately
+	  # isn't a blessed tool.
+	  $opt_dry_run || $SED -e '/[ ,]DATA/!d;s,\(.*\)\([ \,].*\),s|^\1$|\1\2|,' < $export_symbols > $output_objdir/$libname.filter
+	  func_append delfiles " $export_symbols $output_objdir/$libname.filter"
+	  export_symbols=$output_objdir/$libname.def
+	  $opt_dry_run || $SED -f $output_objdir/$libname.filter < $orig_export_symbols > $export_symbols
+	fi
+
+	tmp_deplibs=
+	for test_deplib in $deplibs; do
+	  case " $convenience " in
+	  *" $test_deplib "*) ;;
+	  *)
+	    func_append tmp_deplibs " $test_deplib"
+	    ;;
+	  esac
+	done
+	deplibs=$tmp_deplibs
+
+	if test -n "$convenience"; then
+	  if test -n "$whole_archive_flag_spec" &&
+	    test yes = "$compiler_needs_object" &&
+	    test -z "$libobjs"; then
+	    # extract the archives, so we have objects to list.
+	    # TODO: could optimize this to just extract one archive.
+	    whole_archive_flag_spec=
+	  fi
+	  if test -n "$whole_archive_flag_spec"; then
+	    save_libobjs=$libobjs
+	    eval libobjs=\"\$libobjs $whole_archive_flag_spec\"
+	    test "X$libobjs" = "X " && libobjs=
+	  else
+	    gentop=$output_objdir/${outputname}x
+	    func_append generated " $gentop"
+
+	    func_extract_archives $gentop $convenience
+	    func_append libobjs " $func_extract_archives_result"
+	    test "X$libobjs" = "X " && libobjs=
+	  fi
+	fi
+
+	if test yes = "$thread_safe" && test -n "$thread_safe_flag_spec"; then
+	  eval flag=\"$thread_safe_flag_spec\"
+	  func_append linker_flags " $flag"
+	fi
+
+	# Make a backup of the uninstalled library when relinking
+	if test relink = "$opt_mode"; then
+	  $opt_dry_run || eval '(cd $output_objdir && $RM ${realname}U && $MV $realname ${realname}U)' || exit $?
+	fi
+
+	# Do each of the archive commands.
+	if test yes = "$module" && test -n "$module_cmds"; then
+	  if test -n "$export_symbols" && test -n "$module_expsym_cmds"; then
+	    eval test_cmds=\"$module_expsym_cmds\"
+	    cmds=$module_expsym_cmds
+	  else
+	    eval test_cmds=\"$module_cmds\"
+	    cmds=$module_cmds
+	  fi
+	else
+	  if test -n "$export_symbols" && test -n "$archive_expsym_cmds"; then
+	    eval test_cmds=\"$archive_expsym_cmds\"
+	    cmds=$archive_expsym_cmds
+	  else
+	    eval test_cmds=\"$archive_cmds\"
+	    cmds=$archive_cmds
+	  fi
+	fi
+
+	if test : != "$skipped_export" &&
+	   func_len " $test_cmds" &&
+	   len=$func_len_result &&
+	   test "$len" -lt "$max_cmd_len" || test "$max_cmd_len" -le -1; then
+	  :
+	else
+	  # The command line is too long to link in one step, link piecewise
+	  # or, if using GNU ld and skipped_export is not :, use a linker
+	  # script.
+
+	  # Save the value of $output and $libobjs because we want to
+	  # use them later.  If we have whole_archive_flag_spec, we
+	  # want to use save_libobjs as it was before
+	  # whole_archive_flag_spec was expanded, because we can't
+	  # assume the linker understands whole_archive_flag_spec.
+	  # This may have to be revisited, in case too many
+	  # convenience libraries get linked in and end up exceeding
+	  # the spec.
+	  if test -z "$convenience" || test -z "$whole_archive_flag_spec"; then
+	    save_libobjs=$libobjs
+	  fi
+	  save_output=$output
+	  func_basename "$output"
+	  output_la=$func_basename_result
+
+	  # Clear the reloadable object creation command queue and
+	  # initialize k to one.
+	  test_cmds=
+	  concat_cmds=
+	  objlist=
+	  last_robj=
+	  k=1
+
+	  if test -n "$save_libobjs" && test : != "$skipped_export" && test yes = "$with_gnu_ld"; then
+	    output=$output_objdir/$output_la.lnkscript
+	    func_verbose "creating GNU ld script: $output"
+	    echo 'INPUT (' > $output
+	    for obj in $save_libobjs
+	    do
+	      func_to_tool_file "$obj"
+	      $ECHO "$func_to_tool_file_result" >> $output
+	    done
+	    echo ')' >> $output
+	    func_append delfiles " $output"
+	    func_to_tool_file "$output"
+	    output=$func_to_tool_file_result
+	  elif test -n "$save_libobjs" && test : != "$skipped_export" && test -n "$file_list_spec"; then
+	    output=$output_objdir/$output_la.lnk
+	    func_verbose "creating linker input file list: $output"
+	    : > $output
+	    set x $save_libobjs
+	    shift
+	    firstobj=
+	    if test yes = "$compiler_needs_object"; then
+	      firstobj="$1 "
+	      shift
+	    fi
+	    for obj
+	    do
+	      func_to_tool_file "$obj"
+	      $ECHO "$func_to_tool_file_result" >> $output
+	    done
+	    func_append delfiles " $output"
+	    func_to_tool_file "$output"
+	    output=$firstobj\"$file_list_spec$func_to_tool_file_result\"
+	  else
+	    if test -n "$save_libobjs"; then
+	      func_verbose "creating reloadable object files..."
+	      output=$output_objdir/$output_la-$k.$objext
+	      eval test_cmds=\"$reload_cmds\"
+	      func_len " $test_cmds"
+	      len0=$func_len_result
+	      len=$len0
+
+	      # Loop over the list of objects to be linked.
+	      for obj in $save_libobjs
+	      do
+		func_len " $obj"
+		func_arith $len + $func_len_result
+		len=$func_arith_result
+		if test -z "$objlist" ||
+		   test "$len" -lt "$max_cmd_len"; then
+		  func_append objlist " $obj"
+		else
+		  # The command $test_cmds is almost too long, add a
+		  # command to the queue.
+		  if test 1 -eq "$k"; then
+		    # The first file doesn't have a previous command to add.
+		    reload_objs=$objlist
+		    eval concat_cmds=\"$reload_cmds\"
+		  else
+		    # All subsequent reloadable object files will link in
+		    # the last one created.
+		    reload_objs="$objlist $last_robj"
+		    eval concat_cmds=\"\$concat_cmds~$reload_cmds~\$RM $last_robj\"
+		  fi
+		  last_robj=$output_objdir/$output_la-$k.$objext
+		  func_arith $k + 1
+		  k=$func_arith_result
+		  output=$output_objdir/$output_la-$k.$objext
+		  objlist=" $obj"
+		  func_len " $last_robj"
+		  func_arith $len0 + $func_len_result
+		  len=$func_arith_result
+		fi
+	      done
+	      # Handle the remaining objects by creating one last
+	      # reloadable object file.  All subsequent reloadable object
+	      # files will link in the last one created.
+	      test -z "$concat_cmds" || concat_cmds=$concat_cmds~
+	      reload_objs="$objlist $last_robj"
+	      eval concat_cmds=\"\$concat_cmds$reload_cmds\"
+	      if test -n "$last_robj"; then
+	        eval concat_cmds=\"\$concat_cmds~\$RM $last_robj\"
+	      fi
+	      func_append delfiles " $output"
+
+	    else
+	      output=
+	    fi
+
+	    ${skipped_export-false} && {
+	      func_verbose "generating symbol list for '$libname.la'"
+	      export_symbols=$output_objdir/$libname.exp
+	      $opt_dry_run || $RM $export_symbols
+	      libobjs=$output
+	      # Append the command to create the export file.
+	      test -z "$concat_cmds" || concat_cmds=$concat_cmds~
+	      eval concat_cmds=\"\$concat_cmds$export_symbols_cmds\"
+	      if test -n "$last_robj"; then
+		eval concat_cmds=\"\$concat_cmds~\$RM $last_robj\"
+	      fi
+	    }
+
+	    test -n "$save_libobjs" &&
+	      func_verbose "creating a temporary reloadable object file: $output"
+
+	    # Loop through the commands generated above and execute them.
+	    save_ifs=$IFS; IFS='~'
+	    for cmd in $concat_cmds; do
+	      IFS=$save_ifs
+	      $opt_quiet || {
+		  func_quote_arg expand,pretty "$cmd"
+		  eval "func_echo $func_quote_arg_result"
+	      }
+	      $opt_dry_run || eval "$cmd" || {
+		lt_exit=$?
+
+		# Restore the uninstalled library and exit
+		if test relink = "$opt_mode"; then
+		  ( cd "$output_objdir" && \
+		    $RM "${realname}T" && \
+		    $MV "${realname}U" "$realname" )
+		fi
+
+		exit $lt_exit
+	      }
+	    done
+	    IFS=$save_ifs
+
+	    if test -n "$export_symbols_regex" && ${skipped_export-false}; then
+	      func_show_eval '$EGREP -e "$export_symbols_regex" "$export_symbols" > "${export_symbols}T"'
+	      func_show_eval '$MV "${export_symbols}T" "$export_symbols"'
+	    fi
+	  fi
+
+          ${skipped_export-false} && {
+	    if test -n "$export_symbols" && test -n "$include_expsyms"; then
+	      tmp_export_symbols=$export_symbols
+	      test -n "$orig_export_symbols" && tmp_export_symbols=$orig_export_symbols
+	      $opt_dry_run || eval '$ECHO "$include_expsyms" | $SP2NL >> "$tmp_export_symbols"'
+	    fi
+
+	    if test -n "$orig_export_symbols"; then
+	      # The given exports_symbols file has to be filtered, so filter it.
+	      func_verbose "filter symbol list for '$libname.la' to tag DATA exports"
+	      # FIXME: $output_objdir/$libname.filter potentially contains lots of
+	      # 's' commands, which not all seds can handle. GNU sed should be fine
+	      # though. Also, the filter scales superlinearly with the number of
+	      # global variables. join(1) would be nice here, but unfortunately
+	      # isn't a blessed tool.
+	      $opt_dry_run || $SED -e '/[ ,]DATA/!d;s,\(.*\)\([ \,].*\),s|^\1$|\1\2|,' < $export_symbols > $output_objdir/$libname.filter
+	      func_append delfiles " $export_symbols $output_objdir/$libname.filter"
+	      export_symbols=$output_objdir/$libname.def
+	      $opt_dry_run || $SED -f $output_objdir/$libname.filter < $orig_export_symbols > $export_symbols
+	    fi
+	  }
+
+	  libobjs=$output
+	  # Restore the value of output.
+	  output=$save_output
+
+	  if test -n "$convenience" && test -n "$whole_archive_flag_spec"; then
+	    eval libobjs=\"\$libobjs $whole_archive_flag_spec\"
+	    test "X$libobjs" = "X " && libobjs=
+	  fi
+	  # Expand the library linking commands again to reset the
+	  # value of $libobjs for piecewise linking.
+
+	  # Do each of the archive commands.
+	  if test yes = "$module" && test -n "$module_cmds"; then
+	    if test -n "$export_symbols" && test -n "$module_expsym_cmds"; then
+	      cmds=$module_expsym_cmds
+	    else
+	      cmds=$module_cmds
+	    fi
+	  else
+	    if test -n "$export_symbols" && test -n "$archive_expsym_cmds"; then
+	      cmds=$archive_expsym_cmds
+	    else
+	      cmds=$archive_cmds
+	    fi
+	  fi
+	fi
+
+	if test -n "$delfiles"; then
+	  # Append the command to remove temporary files to $cmds.
+	  eval cmds=\"\$cmds~\$RM $delfiles\"
+	fi
+
+	# Add any objects from preloaded convenience libraries
+	if test -n "$dlprefiles"; then
+	  gentop=$output_objdir/${outputname}x
+	  func_append generated " $gentop"
+
+	  func_extract_archives $gentop $dlprefiles
+	  func_append libobjs " $func_extract_archives_result"
+	  test "X$libobjs" = "X " && libobjs=
+	fi
+
+	save_ifs=$IFS; IFS='~'
+	for cmd in $cmds; do
+	  IFS=$sp$nl
+	  eval cmd=\"$cmd\"
+	  IFS=$save_ifs
+	  $opt_quiet || {
+	    func_quote_arg expand,pretty "$cmd"
+	    eval "func_echo $func_quote_arg_result"
+	  }
+	  $opt_dry_run || eval "$cmd" || {
+	    lt_exit=$?
+
+	    # Restore the uninstalled library and exit
+	    if test relink = "$opt_mode"; then
+	      ( cd "$output_objdir" && \
+	        $RM "${realname}T" && \
+		$MV "${realname}U" "$realname" )
+	    fi
+
+	    exit $lt_exit
+	  }
+	done
+	IFS=$save_ifs
+
+	# Restore the uninstalled library and exit
+	if test relink = "$opt_mode"; then
+	  $opt_dry_run || eval '(cd $output_objdir && $RM ${realname}T && $MV $realname ${realname}T && $MV ${realname}U $realname)' || exit $?
+
+	  if test -n "$convenience"; then
+	    if test -z "$whole_archive_flag_spec"; then
+	      func_show_eval '${RM}r "$gentop"'
+	    fi
+	  fi
+
+	  exit $EXIT_SUCCESS
+	fi
+
+	# Create links to the real library.
+	for linkname in $linknames; do
+	  if test "$realname" != "$linkname"; then
+	    func_show_eval '(cd "$output_objdir" && $RM "$linkname" && $LN_S "$realname" "$linkname")' 'exit $?'
+	  fi
+	done
+
+	# If -module or -export-dynamic was specified, set the dlname.
+	if test yes = "$module" || test yes = "$export_dynamic"; then
+	  # On all known operating systems, these are identical.
+	  dlname=$soname
+	fi
+      fi
+      ;;
+
+    obj)
+      if test -n "$dlfiles$dlprefiles" || test no != "$dlself"; then
+	func_warning "'-dlopen' is ignored for objects"
+      fi
+
+      case " $deplibs" in
+      *\ -l* | *\ -L*)
+	func_warning "'-l' and '-L' are ignored for objects" ;;
+      esac
+
+      test -n "$rpath" && \
+	func_warning "'-rpath' is ignored for objects"
+
+      test -n "$xrpath" && \
+	func_warning "'-R' is ignored for objects"
+
+      test -n "$vinfo" && \
+	func_warning "'-version-info' is ignored for objects"
+
+      test -n "$release" && \
+	func_warning "'-release' is ignored for objects"
+
+      case $output in
+      *.lo)
+	test -n "$objs$old_deplibs" && \
+	  func_fatal_error "cannot build library object '$output' from non-libtool objects"
+
+	libobj=$output
+	func_lo2o "$libobj"
+	obj=$func_lo2o_result
+	;;
+      *)
+	libobj=
+	obj=$output
+	;;
+      esac
+
+      # Delete the old objects.
+      $opt_dry_run || $RM $obj $libobj
+
+      # Objects from convenience libraries.  This assumes
+      # single-version convenience libraries.  Whenever we create
+      # different ones for PIC/non-PIC, this we'll have to duplicate
+      # the extraction.
+      reload_conv_objs=
+      gentop=
+      # if reload_cmds runs $LD directly, get rid of -Wl from
+      # whole_archive_flag_spec and hope we can get by with turning comma
+      # into space.
+      case $reload_cmds in
+        *\$LD[\ \$]*) wl= ;;
+      esac
+      if test -n "$convenience"; then
+	if test -n "$whole_archive_flag_spec"; then
+	  eval tmp_whole_archive_flags=\"$whole_archive_flag_spec\"
+	  test -n "$wl" || tmp_whole_archive_flags=`$ECHO "$tmp_whole_archive_flags" | $SED 's|,| |g'`
+	  reload_conv_objs=$reload_objs\ $tmp_whole_archive_flags
+	else
+	  gentop=$output_objdir/${obj}x
+	  func_append generated " $gentop"
+
+	  func_extract_archives $gentop $convenience
+	  reload_conv_objs="$reload_objs $func_extract_archives_result"
+	fi
+      fi
+
+      # If we're not building shared, we need to use non_pic_objs
+      test yes = "$build_libtool_libs" || libobjs=$non_pic_objects
+
+      # Create the old-style object.
+      reload_objs=$objs$old_deplibs' '`$ECHO "$libobjs" | $SP2NL | $SED "/\.$libext$/d; /\.lib$/d; $lo2o" | $NL2SP`' '$reload_conv_objs
+
+      output=$obj
+      func_execute_cmds "$reload_cmds" 'exit $?'
+
+      # Exit if we aren't doing a library object file.
+      if test -z "$libobj"; then
+	if test -n "$gentop"; then
+	  func_show_eval '${RM}r "$gentop"'
+	fi
+
+	exit $EXIT_SUCCESS
+      fi
+
+      test yes = "$build_libtool_libs" || {
+	if test -n "$gentop"; then
+	  func_show_eval '${RM}r "$gentop"'
+	fi
+
+	# Create an invalid libtool object if no PIC, so that we don't
+	# accidentally link it into a program.
+	# $show "echo timestamp > $libobj"
+	# $opt_dry_run || eval "echo timestamp > $libobj" || exit $?
+	exit $EXIT_SUCCESS
+      }
+
+      if test -n "$pic_flag" || test default != "$pic_mode"; then
+	# Only do commands if we really have different PIC objects.
+	reload_objs="$libobjs $reload_conv_objs"
+	output=$libobj
+	func_execute_cmds "$reload_cmds" 'exit $?'
+      fi
+
+      if test -n "$gentop"; then
+	func_show_eval '${RM}r "$gentop"'
+      fi
+
+      exit $EXIT_SUCCESS
+      ;;
+
+    prog)
+      case $host in
+	*cygwin*) func_stripname '' '.exe' "$output"
+	          output=$func_stripname_result.exe;;
+      esac
+      test -n "$vinfo" && \
+	func_warning "'-version-info' is ignored for programs"
+
+      test -n "$release" && \
+	func_warning "'-release' is ignored for programs"
+
+      $preload \
+	&& test unknown,unknown,unknown = "$dlopen_support,$dlopen_self,$dlopen_self_static" \
+	&& func_warning "'LT_INIT([dlopen])' not used. Assuming no dlopen support."
+
+      case $host in
+      *-*-rhapsody* | *-*-darwin1.[012])
+	# On Rhapsody replace the C library is the System framework
+	compile_deplibs=`$ECHO " $compile_deplibs" | $SED 's/ -lc / System.ltframework /'`
+	finalize_deplibs=`$ECHO " $finalize_deplibs" | $SED 's/ -lc / System.ltframework /'`
+	;;
+      esac
+
+      case $host in
+      *-*-darwin*)
+	# Don't allow lazy linking, it breaks C++ global constructors
+	# But is supposedly fixed on 10.4 or later (yay!).
+	if test CXX = "$tagname"; then
+	  case ${MACOSX_DEPLOYMENT_TARGET-10.0} in
+	    10.[0123])
+	      func_append compile_command " $wl-bind_at_load"
+	      func_append finalize_command " $wl-bind_at_load"
+	    ;;
+	  esac
+	fi
+	# Time to change all our "foo.ltframework" stuff back to "-framework foo"
+	compile_deplibs=`$ECHO " $compile_deplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	finalize_deplibs=`$ECHO " $finalize_deplibs" | $SED 's% \([^ $]*\).ltframework% -framework \1%g'`
+	;;
+      esac
+
+
+      # move library search paths that coincide with paths to not yet
+      # installed libraries to the beginning of the library search list
+      new_libs=
+      for path in $notinst_path; do
+	case " $new_libs " in
+	*" -L$path/$objdir "*) ;;
+	*)
+	  case " $compile_deplibs " in
+	  *" -L$path/$objdir "*)
+	    func_append new_libs " -L$path/$objdir" ;;
+	  esac
+	  ;;
+	esac
+      done
+      for deplib in $compile_deplibs; do
+	case $deplib in
+	-L*)
+	  case " $new_libs " in
+	  *" $deplib "*) ;;
+	  *) func_append new_libs " $deplib" ;;
+	  esac
+	  ;;
+	*) func_append new_libs " $deplib" ;;
+	esac
+      done
+      compile_deplibs=$new_libs
+
+
+      func_append compile_command " $compile_deplibs"
+      func_append finalize_command " $finalize_deplibs"
+
+      if test -n "$rpath$xrpath"; then
+	# If the user specified any rpath flags, then add them.
+	for libdir in $rpath $xrpath; do
+	  # This is the magic to use -rpath.
+	  case "$finalize_rpath " in
+	  *" $libdir "*) ;;
+	  *) func_append finalize_rpath " $libdir" ;;
+	  esac
+	done
+      fi
+
+      # Now hardcode the library paths
+      rpath=
+      hardcode_libdirs=
+      for libdir in $compile_rpath $finalize_rpath; do
+	if test -n "$hardcode_libdir_flag_spec"; then
+	  if test -n "$hardcode_libdir_separator"; then
+	    if test -z "$hardcode_libdirs"; then
+	      hardcode_libdirs=$libdir
+	    else
+	      # Just accumulate the unique libdirs.
+	      case $hardcode_libdir_separator$hardcode_libdirs$hardcode_libdir_separator in
+	      *"$hardcode_libdir_separator$libdir$hardcode_libdir_separator"*)
+		;;
+	      *)
+		func_append hardcode_libdirs "$hardcode_libdir_separator$libdir"
+		;;
+	      esac
+	    fi
+	  else
+	    eval flag=\"$hardcode_libdir_flag_spec\"
+	    func_append rpath " $flag"
+	  fi
+	elif test -n "$runpath_var"; then
+	  case "$perm_rpath " in
+	  *" $libdir "*) ;;
+	  *) func_append perm_rpath " $libdir" ;;
+	  esac
+	fi
+	case $host in
+	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
+	  testbindir=`$ECHO "$libdir" | $SED -e 's*/lib$*/bin*'`
+	  case :$dllsearchpath: in
+	  *":$libdir:"*) ;;
+	  ::) dllsearchpath=$libdir;;
+	  *) func_append dllsearchpath ":$libdir";;
+	  esac
+	  case :$dllsearchpath: in
+	  *":$testbindir:"*) ;;
+	  ::) dllsearchpath=$testbindir;;
+	  *) func_append dllsearchpath ":$testbindir";;
+	  esac
+	  ;;
+	esac
+      done
+      # Substitute the hardcoded libdirs into the rpath.
+      if test -n "$hardcode_libdir_separator" &&
+	 test -n "$hardcode_libdirs"; then
+	libdir=$hardcode_libdirs
+	eval rpath=\" $hardcode_libdir_flag_spec\"
+      fi
+      compile_rpath=$rpath
+
+      rpath=
+      hardcode_libdirs=
+      for libdir in $finalize_rpath; do
+	if test -n "$hardcode_libdir_flag_spec"; then
+	  if test -n "$hardcode_libdir_separator"; then
+	    if test -z "$hardcode_libdirs"; then
+	      hardcode_libdirs=$libdir
+	    else
+	      # Just accumulate the unique libdirs.
+	      case $hardcode_libdir_separator$hardcode_libdirs$hardcode_libdir_separator in
+	      *"$hardcode_libdir_separator$libdir$hardcode_libdir_separator"*)
+		;;
+	      *)
+		func_append hardcode_libdirs "$hardcode_libdir_separator$libdir"
+		;;
+	      esac
+	    fi
+	  else
+	    eval flag=\"$hardcode_libdir_flag_spec\"
+	    func_append rpath " $flag"
+	  fi
+	elif test -n "$runpath_var"; then
+	  case "$finalize_perm_rpath " in
+	  *" $libdir "*) ;;
+	  *) func_append finalize_perm_rpath " $libdir" ;;
+	  esac
+	fi
+      done
+      # Substitute the hardcoded libdirs into the rpath.
+      if test -n "$hardcode_libdir_separator" &&
+	 test -n "$hardcode_libdirs"; then
+	libdir=$hardcode_libdirs
+	eval rpath=\" $hardcode_libdir_flag_spec\"
+      fi
+      finalize_rpath=$rpath
+
+      if test -n "$libobjs" && test yes = "$build_old_libs"; then
+	# Transform all the library objects into standard objects.
+	compile_command=`$ECHO "$compile_command" | $SP2NL | $SED "$lo2o" | $NL2SP`
+	finalize_command=`$ECHO "$finalize_command" | $SP2NL | $SED "$lo2o" | $NL2SP`
+      fi
+
+      func_generate_dlsyms "$outputname" "@PROGRAM@" false
+
+      # template prelinking step
+      if test -n "$prelink_cmds"; then
+	func_execute_cmds "$prelink_cmds" 'exit $?'
+      fi
+
+      wrappers_required=:
+      case $host in
+      *cegcc* | *mingw32ce*)
+        # Disable wrappers for cegcc and mingw32ce hosts, we are cross compiling anyway.
+        wrappers_required=false
+        ;;
+      *cygwin* | *mingw* )
+        test yes = "$build_libtool_libs" || wrappers_required=false
+        ;;
+      *)
+        if test no = "$need_relink" || test yes != "$build_libtool_libs"; then
+          wrappers_required=false
+        fi
+        ;;
+      esac
+      $wrappers_required || {
+	# Replace the output file specification.
+	compile_command=`$ECHO "$compile_command" | $SED 's%@OUTPUT@%'"$output"'%g'`
+	link_command=$compile_command$compile_rpath
+
+	# We have no uninstalled library dependencies, so finalize right now.
+	exit_status=0
+	func_show_eval "$link_command" 'exit_status=$?'
+
+	if test -n "$postlink_cmds"; then
+	  func_to_tool_file "$output"
+	  postlink_cmds=`func_echo_all "$postlink_cmds" | $SED -e 's%@OUTPUT@%'"$output"'%g' -e 's%@TOOL_OUTPUT@%'"$func_to_tool_file_result"'%g'`
+	  func_execute_cmds "$postlink_cmds" 'exit $?'
+	fi
+
+	# Delete the generated files.
+	if test -f "$output_objdir/${outputname}S.$objext"; then
+	  func_show_eval '$RM "$output_objdir/${outputname}S.$objext"'
+	fi
+
+	exit $exit_status
+      }
+
+      if test -n "$compile_shlibpath$finalize_shlibpath"; then
+	compile_command="$shlibpath_var=\"$compile_shlibpath$finalize_shlibpath\$$shlibpath_var\" $compile_command"
+      fi
+      if test -n "$finalize_shlibpath"; then
+	finalize_command="$shlibpath_var=\"$finalize_shlibpath\$$shlibpath_var\" $finalize_command"
+      fi
+
+      compile_var=
+      finalize_var=
+      if test -n "$runpath_var"; then
+	if test -n "$perm_rpath"; then
+	  # We should set the runpath_var.
+	  rpath=
+	  for dir in $perm_rpath; do
+	    func_append rpath "$dir:"
+	  done
+	  compile_var="$runpath_var=\"$rpath\$$runpath_var\" "
+	fi
+	if test -n "$finalize_perm_rpath"; then
+	  # We should set the runpath_var.
+	  rpath=
+	  for dir in $finalize_perm_rpath; do
+	    func_append rpath "$dir:"
+	  done
+	  finalize_var="$runpath_var=\"$rpath\$$runpath_var\" "
+	fi
+      fi
+
+      if test yes = "$no_install"; then
+	# We don't need to create a wrapper script.
+	link_command=$compile_var$compile_command$compile_rpath
+	# Replace the output file specification.
+	link_command=`$ECHO "$link_command" | $SED 's%@OUTPUT@%'"$output"'%g'`
+	# Delete the old output file.
+	$opt_dry_run || $RM $output
+	# Link the executable and exit
+	func_show_eval "$link_command" 'exit $?'
+
+	if test -n "$postlink_cmds"; then
+	  func_to_tool_file "$output"
+	  postlink_cmds=`func_echo_all "$postlink_cmds" | $SED -e 's%@OUTPUT@%'"$output"'%g' -e 's%@TOOL_OUTPUT@%'"$func_to_tool_file_result"'%g'`
+	  func_execute_cmds "$postlink_cmds" 'exit $?'
+	fi
+
+	exit $EXIT_SUCCESS
+      fi
+
+      case $hardcode_action,$fast_install in
+        relink,*)
+	  # Fast installation is not supported
+	  link_command=$compile_var$compile_command$compile_rpath
+	  relink_command=$finalize_var$finalize_command$finalize_rpath
+
+	  func_warning "this platform does not like uninstalled shared libraries"
+	  func_warning "'$output' will be relinked during installation"
+	  ;;
+        *,yes)
+	  link_command=$finalize_var$compile_command$finalize_rpath
+	  relink_command=`$ECHO "$compile_var$compile_command$compile_rpath" | $SED 's%@OUTPUT@%\$progdir/\$file%g'`
+          ;;
+	*,no)
+	  link_command=$compile_var$compile_command$compile_rpath
+	  relink_command=$finalize_var$finalize_command$finalize_rpath
+          ;;
+	*,needless)
+	  link_command=$finalize_var$compile_command$finalize_rpath
+	  relink_command=
+          ;;
+      esac
+
+      # Replace the output file specification.
+      link_command=`$ECHO "$link_command" | $SED 's%@OUTPUT@%'"$output_objdir/$outputname"'%g'`
+
+      # Delete the old output files.
+      $opt_dry_run || $RM $output $output_objdir/$outputname $output_objdir/lt-$outputname
+
+      func_show_eval "$link_command" 'exit $?'
+
+      if test -n "$postlink_cmds"; then
+	func_to_tool_file "$output_objdir/$outputname"
+	postlink_cmds=`func_echo_all "$postlink_cmds" | $SED -e 's%@OUTPUT@%'"$output_objdir/$outputname"'%g' -e 's%@TOOL_OUTPUT@%'"$func_to_tool_file_result"'%g'`
+	func_execute_cmds "$postlink_cmds" 'exit $?'
+      fi
+
+      # Now create the wrapper script.
+      func_verbose "creating $output"
+
+      # Quote the relink command for shipping.
+      if test -n "$relink_command"; then
+	# Preserve any variables that may affect compiler behavior
+	for var in $variables_saved_for_relink; do
+	  if eval test -z \"\${$var+set}\"; then
+	    relink_command="{ test -z \"\${$var+set}\" || $lt_unset $var || { $var=; export $var; }; }; $relink_command"
+	  elif eval var_value=\$$var; test -z "$var_value"; then
+	    relink_command="$var=; export $var; $relink_command"
+	  else
+	    func_quote_arg pretty "$var_value"
+	    relink_command="$var=$func_quote_arg_result; export $var; $relink_command"
+	  fi
+	done
+	func_quote eval cd "`pwd`"
+	func_quote_arg pretty,unquoted "($func_quote_result; $relink_command)"
+	relink_command=$func_quote_arg_unquoted_result
+      fi
+
+      # Only actually do things if not in dry run mode.
+      $opt_dry_run || {
+	# win32 will think the script is a binary if it has
+	# a .exe suffix, so we strip it off here.
+	case $output in
+	  *.exe) func_stripname '' '.exe' "$output"
+	         output=$func_stripname_result ;;
+	esac
+	# test for cygwin because mv fails w/o .exe extensions
+	case $host in
+	  *cygwin*)
+	    exeext=.exe
+	    func_stripname '' '.exe' "$outputname"
+	    outputname=$func_stripname_result ;;
+	  *) exeext= ;;
+	esac
+	case $host in
+	  *cygwin* | *mingw* )
+	    func_dirname_and_basename "$output" "" "."
+	    output_name=$func_basename_result
+	    output_path=$func_dirname_result
+	    cwrappersource=$output_path/$objdir/lt-$output_name.c
+	    cwrapper=$output_path/$output_name.exe
+	    $RM $cwrappersource $cwrapper
+	    trap "$RM $cwrappersource $cwrapper; exit $EXIT_FAILURE" 1 2 15
+
+	    func_emit_cwrapperexe_src > $cwrappersource
+
+	    # The wrapper executable is built using the $host compiler,
+	    # because it contains $host paths and files. If cross-
+	    # compiling, it, like the target executable, must be
+	    # executed on the $host or under an emulation environment.
+	    $opt_dry_run || {
+	      $LTCC $LTCFLAGS -o $cwrapper $cwrappersource
+	      $STRIP $cwrapper
+	    }
+
+	    # Now, create the wrapper script for func_source use:
+	    func_ltwrapper_scriptname $cwrapper
+	    $RM $func_ltwrapper_scriptname_result
+	    trap "$RM $func_ltwrapper_scriptname_result; exit $EXIT_FAILURE" 1 2 15
+	    $opt_dry_run || {
+	      # note: this script will not be executed, so do not chmod.
+	      if test "x$build" = "x$host"; then
+		$cwrapper --lt-dump-script > $func_ltwrapper_scriptname_result
+	      else
+		func_emit_wrapper no > $func_ltwrapper_scriptname_result
+	      fi
+	    }
+	  ;;
+	  * )
+	    $RM $output
+	    trap "$RM $output; exit $EXIT_FAILURE" 1 2 15
+
+	    func_emit_wrapper no > $output
+	    chmod +x $output
+	  ;;
+	esac
+      }
+      exit $EXIT_SUCCESS
+      ;;
+    esac
+
+    # See if we need to build an old-fashioned archive.
+    for oldlib in $oldlibs; do
+
+      case $build_libtool_libs in
+        convenience)
+	  oldobjs="$libobjs_save $symfileobj"
+	  addlibs=$convenience
+	  build_libtool_libs=no
+	  ;;
+	module)
+	  oldobjs=$libobjs_save
+	  addlibs=$old_convenience
+	  build_libtool_libs=no
+          ;;
+	*)
+	  oldobjs="$old_deplibs $non_pic_objects"
+	  $preload && test -f "$symfileobj" \
+	    && func_append oldobjs " $symfileobj"
+	  addlibs=$old_convenience
+	  ;;
+      esac
+
+      if test -n "$addlibs"; then
+	gentop=$output_objdir/${outputname}x
+	func_append generated " $gentop"
+
+	func_extract_archives $gentop $addlibs
+	func_append oldobjs " $func_extract_archives_result"
+      fi
+
+      # Do each command in the archive commands.
+      if test -n "$old_archive_from_new_cmds" && test yes = "$build_libtool_libs"; then
+	cmds=$old_archive_from_new_cmds
+      else
+
+	# Add any objects from preloaded convenience libraries
+	if test -n "$dlprefiles"; then
+	  gentop=$output_objdir/${outputname}x
+	  func_append generated " $gentop"
+
+	  func_extract_archives $gentop $dlprefiles
+	  func_append oldobjs " $func_extract_archives_result"
+	fi
+
+	# POSIX demands no paths to be encoded in archives.  We have
+	# to avoid creating archives with duplicate basenames if we
+	# might have to extract them afterwards, e.g., when creating a
+	# static archive out of a convenience library, or when linking
+	# the entirety of a libtool archive into another (currently
+	# not supported by libtool).
+	if (for obj in $oldobjs
+	    do
+	      func_basename "$obj"
+	      $ECHO "$func_basename_result"
+	    done | sort | sort -uc >/dev/null 2>&1); then
+	  :
+	else
+	  echo "copying selected object files to avoid basename conflicts..."
+	  gentop=$output_objdir/${outputname}x
+	  func_append generated " $gentop"
+	  func_mkdir_p "$gentop"
+	  save_oldobjs=$oldobjs
+	  oldobjs=
+	  counter=1
+	  for obj in $save_oldobjs
+	  do
+	    func_basename "$obj"
+	    objbase=$func_basename_result
+	    case " $oldobjs " in
+	    " ") oldobjs=$obj ;;
+	    *[\ /]"$objbase "*)
+	      while :; do
+		# Make sure we don't pick an alternate name that also
+		# overlaps.
+		newobj=lt$counter-$objbase
+		func_arith $counter + 1
+		counter=$func_arith_result
+		case " $oldobjs " in
+		*[\ /]"$newobj "*) ;;
+		*) if test ! -f "$gentop/$newobj"; then break; fi ;;
+		esac
+	      done
+	      func_show_eval "ln $obj $gentop/$newobj || cp $obj $gentop/$newobj"
+	      func_append oldobjs " $gentop/$newobj"
+	      ;;
+	    *) func_append oldobjs " $obj" ;;
+	    esac
+	  done
+	fi
+	func_to_tool_file "$oldlib" func_convert_file_msys_to_w32
+	tool_oldlib=$func_to_tool_file_result
+	eval cmds=\"$old_archive_cmds\"
+
+	func_len " $cmds"
+	len=$func_len_result
+	if test "$len" -lt "$max_cmd_len" || test "$max_cmd_len" -le -1; then
+	  cmds=$old_archive_cmds
+	elif test -n "$archiver_list_spec"; then
+	  func_verbose "using command file archive linking..."
+	  for obj in $oldobjs
+	  do
+	    func_to_tool_file "$obj"
+	    $ECHO "$func_to_tool_file_result"
+	  done > $output_objdir/$libname.libcmd
+	  func_to_tool_file "$output_objdir/$libname.libcmd"
+	  oldobjs=" $archiver_list_spec$func_to_tool_file_result"
+	  cmds=$old_archive_cmds
+	else
+	  # the command line is too long to link in one step, link in parts
+	  func_verbose "using piecewise archive linking..."
+	  save_RANLIB=$RANLIB
+	  RANLIB=:
+	  objlist=
+	  concat_cmds=
+	  save_oldobjs=$oldobjs
+	  oldobjs=
+	  # Is there a better way of finding the last object in the list?
+	  for obj in $save_oldobjs
+	  do
+	    last_oldobj=$obj
+	  done
+	  eval test_cmds=\"$old_archive_cmds\"
+	  func_len " $test_cmds"
+	  len0=$func_len_result
+	  len=$len0
+	  for obj in $save_oldobjs
+	  do
+	    func_len " $obj"
+	    func_arith $len + $func_len_result
+	    len=$func_arith_result
+	    func_append objlist " $obj"
+	    if test "$len" -lt "$max_cmd_len"; then
+	      :
+	    else
+	      # the above command should be used before it gets too long
+	      oldobjs=$objlist
+	      if test "$obj" = "$last_oldobj"; then
+		RANLIB=$save_RANLIB
+	      fi
+	      test -z "$concat_cmds" || concat_cmds=$concat_cmds~
+	      eval concat_cmds=\"\$concat_cmds$old_archive_cmds\"
+	      objlist=
+	      len=$len0
+	    fi
+	  done
+	  RANLIB=$save_RANLIB
+	  oldobjs=$objlist
+	  if test -z "$oldobjs"; then
+	    eval cmds=\"\$concat_cmds\"
+	  else
+	    eval cmds=\"\$concat_cmds~\$old_archive_cmds\"
+	  fi
+	fi
+      fi
+      func_execute_cmds "$cmds" 'exit $?'
+    done
+
+    test -n "$generated" && \
+      func_show_eval "${RM}r$generated"
+
+    # Now create the libtool archive.
+    case $output in
+    *.la)
+      old_library=
+      test yes = "$build_old_libs" && old_library=$libname.$libext
+      func_verbose "creating $output"
+
+      # Preserve any variables that may affect compiler behavior
+      for var in $variables_saved_for_relink; do
+	if eval test -z \"\${$var+set}\"; then
+	  relink_command="{ test -z \"\${$var+set}\" || $lt_unset $var || { $var=; export $var; }; }; $relink_command"
+	elif eval var_value=\$$var; test -z "$var_value"; then
+	  relink_command="$var=; export $var; $relink_command"
+	else
+	  func_quote_arg pretty,unquoted "$var_value"
+	  relink_command="$var=$func_quote_arg_unquoted_result; export $var; $relink_command"
+	fi
+      done
+      # Quote the link command for shipping.
+      func_quote eval cd "`pwd`"
+      relink_command="($func_quote_result; $SHELL \"$progpath\" $preserve_args --mode=relink $libtool_args @inst_prefix_dir@)"
+      func_quote_arg pretty,unquoted "$relink_command"
+      relink_command=$func_quote_arg_unquoted_result
+      if test yes = "$hardcode_automatic"; then
+	relink_command=
+      fi
+
+      # Only create the output if not a dry run.
+      $opt_dry_run || {
+	for installed in no yes; do
+	  if test yes = "$installed"; then
+	    if test -z "$install_libdir"; then
+	      break
+	    fi
+	    output=$output_objdir/${outputname}i
+	    # Replace all uninstalled libtool libraries with the installed ones
+	    newdependency_libs=
+	    for deplib in $dependency_libs; do
+	      case $deplib in
+	      *.la)
+		func_basename "$deplib"
+		name=$func_basename_result
+		func_resolve_sysroot "$deplib"
+		eval libdir=`$SED -n -e 's/^libdir=\(.*\)$/\1/p' $func_resolve_sysroot_result`
+		test -z "$libdir" && \
+		  func_fatal_error "'$deplib' is not a valid libtool archive"
+		func_append newdependency_libs " ${lt_sysroot:+=}$libdir/$name"
+		;;
+	      -L*)
+		func_stripname -L '' "$deplib"
+		func_replace_sysroot "$func_stripname_result"
+		func_append newdependency_libs " -L$func_replace_sysroot_result"
+		;;
+	      -R*)
+		func_stripname -R '' "$deplib"
+		func_replace_sysroot "$func_stripname_result"
+		func_append newdependency_libs " -R$func_replace_sysroot_result"
+		;;
+	      *) func_append newdependency_libs " $deplib" ;;
+	      esac
+	    done
+	    dependency_libs=$newdependency_libs
+	    newdlfiles=
+
+	    for lib in $dlfiles; do
+	      case $lib in
+	      *.la)
+	        func_basename "$lib"
+		name=$func_basename_result
+		eval libdir=`$SED -n -e 's/^libdir=\(.*\)$/\1/p' $lib`
+		test -z "$libdir" && \
+		  func_fatal_error "'$lib' is not a valid libtool archive"
+		func_append newdlfiles " ${lt_sysroot:+=}$libdir/$name"
+		;;
+	      *) func_append newdlfiles " $lib" ;;
+	      esac
+	    done
+	    dlfiles=$newdlfiles
+	    newdlprefiles=
+	    for lib in $dlprefiles; do
+	      case $lib in
+	      *.la)
+		# Only pass preopened files to the pseudo-archive (for
+		# eventual linking with the app. that links it) if we
+		# didn't already link the preopened objects directly into
+		# the library:
+		func_basename "$lib"
+		name=$func_basename_result
+		eval libdir=`$SED -n -e 's/^libdir=\(.*\)$/\1/p' $lib`
+		test -z "$libdir" && \
+		  func_fatal_error "'$lib' is not a valid libtool archive"
+		func_append newdlprefiles " ${lt_sysroot:+=}$libdir/$name"
+		;;
+	      esac
+	    done
+	    dlprefiles=$newdlprefiles
+	  else
+	    newdlfiles=
+	    for lib in $dlfiles; do
+	      case $lib in
+		[\\/]* | [A-Za-z]:[\\/]*) abs=$lib ;;
+		*) abs=`pwd`"/$lib" ;;
+	      esac
+	      func_append newdlfiles " $abs"
+	    done
+	    dlfiles=$newdlfiles
+	    newdlprefiles=
+	    for lib in $dlprefiles; do
+	      case $lib in
+		[\\/]* | [A-Za-z]:[\\/]*) abs=$lib ;;
+		*) abs=`pwd`"/$lib" ;;
+	      esac
+	      func_append newdlprefiles " $abs"
+	    done
+	    dlprefiles=$newdlprefiles
+	  fi
+	  $RM $output
+	  # place dlname in correct position for cygwin
+	  # In fact, it would be nice if we could use this code for all target
+	  # systems that can't hard-code library paths into their executables
+	  # and that have no shared library path variable independent of PATH,
+	  # but it turns out we can't easily determine that from inspecting
+	  # libtool variables, so we have to hard-code the OSs to which it
+	  # applies here; at the moment, that means platforms that use the PE
+	  # object format with DLL files.  See the long comment at the top of
+	  # tests/bindir.at for full details.
+	  tdlname=$dlname
+	  case $host,$output,$installed,$module,$dlname in
+	    *cygwin*,*lai,yes,no,*.dll | *mingw*,*lai,yes,no,*.dll | *cegcc*,*lai,yes,no,*.dll)
+	      # If a -bindir argument was supplied, place the dll there.
+	      if test -n "$bindir"; then
+		func_relative_path "$install_libdir" "$bindir"
+		tdlname=$func_relative_path_result/$dlname
+	      else
+		# Otherwise fall back on heuristic.
+		tdlname=../bin/$dlname
+	      fi
+	      ;;
+	  esac
+	  $ECHO > $output "\
+# $outputname - a libtool library file
+# Generated by $PROGRAM (GNU $PACKAGE) $VERSION
+#
+# Please DO NOT delete this file!
+# It is necessary for linking the library.
+
+# The name that we can dlopen(3).
+dlname='$tdlname'
+
+# Names of this library.
+library_names='$library_names'
+
+# The name of the static archive.
+old_library='$old_library'
+
+# Linker flags that cannot go in dependency_libs.
+inherited_linker_flags='$new_inherited_linker_flags'
+
+# Libraries that this one depends upon.
+dependency_libs='$dependency_libs'
+
+# Names of additional weak libraries provided by this library
+weak_library_names='$weak_libs'
+
+# Version information for $libname.
+current=$current
+age=$age
+revision=$revision
+
+# Is this an already installed library?
+installed=$installed
+
+# Should we warn about portability when linking against -modules?
+shouldnotlink=$module
+
+# Files to dlopen/dlpreopen
+dlopen='$dlfiles'
+dlpreopen='$dlprefiles'
+
+# Directory that this library needs to be installed in:
+libdir='$install_libdir'"
+	  if test no,yes = "$installed,$need_relink"; then
+	    $ECHO >> $output "\
+relink_command=\"$relink_command\""
+	  fi
+	done
+      }
+
+      # Do a symbolic link so that the libtool archive can be found in
+      # LD_LIBRARY_PATH before the program is installed.
+      func_show_eval '( cd "$output_objdir" && $RM "$outputname" && $LN_S "../$outputname" "$outputname" )' 'exit $?'
+      ;;
+    esac
+    exit $EXIT_SUCCESS
+}
+
+if test link = "$opt_mode" || test relink = "$opt_mode"; then
+  func_mode_link ${1+"$@"}
+fi
+
+
+# func_mode_uninstall arg...
+func_mode_uninstall ()
+{
+    $debug_cmd
+
+    RM=$nonopt
+    files=
+    rmforce=false
+    exit_status=0
+
+    # This variable tells wrapper scripts just to set variables rather
+    # than running their programs.
+    libtool_install_magic=$magic
+
+    for arg
+    do
+      case $arg in
+      -f) func_append RM " $arg"; rmforce=: ;;
+      -*) func_append RM " $arg" ;;
+      *) func_append files " $arg" ;;
+      esac
+    done
+
+    test -z "$RM" && \
+      func_fatal_help "you must specify an RM program"
+
+    rmdirs=
+
+    for file in $files; do
+      func_dirname "$file" "" "."
+      dir=$func_dirname_result
+      if test . = "$dir"; then
+	odir=$objdir
+      else
+	odir=$dir/$objdir
+      fi
+      func_basename "$file"
+      name=$func_basename_result
+      test uninstall = "$opt_mode" && odir=$dir
+
+      # Remember odir for removal later, being careful to avoid duplicates
+      if test clean = "$opt_mode"; then
+	case " $rmdirs " in
+	  *" $odir "*) ;;
+	  *) func_append rmdirs " $odir" ;;
+	esac
+      fi
+
+      # Don't error if the file doesn't exist and rm -f was used.
+      if { test -L "$file"; } >/dev/null 2>&1 ||
+	 { test -h "$file"; } >/dev/null 2>&1 ||
+	 test -f "$file"; then
+	:
+      elif test -d "$file"; then
+	exit_status=1
+	continue
+      elif $rmforce; then
+	continue
+      fi
+
+      rmfiles=$file
+
+      case $name in
+      *.la)
+	# Possibly a libtool archive, so verify it.
+	if func_lalib_p "$file"; then
+	  func_source $dir/$name
+
+	  # Delete the libtool libraries and symlinks.
+	  for n in $library_names; do
+	    func_append rmfiles " $odir/$n"
+	  done
+	  test -n "$old_library" && func_append rmfiles " $odir/$old_library"
+
+	  case $opt_mode in
+	  clean)
+	    case " $library_names " in
+	    *" $dlname "*) ;;
+	    *) test -n "$dlname" && func_append rmfiles " $odir/$dlname" ;;
+	    esac
+	    test -n "$libdir" && func_append rmfiles " $odir/$name $odir/${name}i"
+	    ;;
+	  uninstall)
+	    if test -n "$library_names"; then
+	      # Do each command in the postuninstall commands.
+	      func_execute_cmds "$postuninstall_cmds" '$rmforce || exit_status=1'
+	    fi
+
+	    if test -n "$old_library"; then
+	      # Do each command in the old_postuninstall commands.
+	      func_execute_cmds "$old_postuninstall_cmds" '$rmforce || exit_status=1'
+	    fi
+	    # FIXME: should reinstall the best remaining shared library.
+	    ;;
+	  esac
+	fi
+	;;
+
+      *.lo)
+	# Possibly a libtool object, so verify it.
+	if func_lalib_p "$file"; then
+
+	  # Read the .lo file
+	  func_source $dir/$name
+
+	  # Add PIC object to the list of files to remove.
+	  if test -n "$pic_object" && test none != "$pic_object"; then
+	    func_append rmfiles " $dir/$pic_object"
+	  fi
+
+	  # Add non-PIC object to the list of files to remove.
+	  if test -n "$non_pic_object" && test none != "$non_pic_object"; then
+	    func_append rmfiles " $dir/$non_pic_object"
+	  fi
+	fi
+	;;
+
+      *)
+	if test clean = "$opt_mode"; then
+	  noexename=$name
+	  case $file in
+	  *.exe)
+	    func_stripname '' '.exe' "$file"
+	    file=$func_stripname_result
+	    func_stripname '' '.exe' "$name"
+	    noexename=$func_stripname_result
+	    # $file with .exe has already been added to rmfiles,
+	    # add $file without .exe
+	    func_append rmfiles " $file"
+	    ;;
+	  esac
+	  # Do a test to see if this is a libtool program.
+	  if func_ltwrapper_p "$file"; then
+	    if func_ltwrapper_executable_p "$file"; then
+	      func_ltwrapper_scriptname "$file"
+	      relink_command=
+	      func_source $func_ltwrapper_scriptname_result
+	      func_append rmfiles " $func_ltwrapper_scriptname_result"
+	    else
+	      relink_command=
+	      func_source $dir/$noexename
+	    fi
+
+	    # note $name still contains .exe if it was in $file originally
+	    # as does the version of $file that was added into $rmfiles
+	    func_append rmfiles " $odir/$name $odir/${name}S.$objext"
+	    if test yes = "$fast_install" && test -n "$relink_command"; then
+	      func_append rmfiles " $odir/lt-$name"
+	    fi
+	    if test "X$noexename" != "X$name"; then
+	      func_append rmfiles " $odir/lt-$noexename.c"
+	    fi
+	  fi
+	fi
+	;;
+      esac
+      func_show_eval "$RM $rmfiles" 'exit_status=1'
+    done
+
+    # Try to remove the $objdir's in the directories where we deleted files
+    for dir in $rmdirs; do
+      if test -d "$dir"; then
+	func_show_eval "rmdir $dir >/dev/null 2>&1"
+      fi
+    done
+
+    exit $exit_status
+}
+
+if test uninstall = "$opt_mode" || test clean = "$opt_mode"; then
+  func_mode_uninstall ${1+"$@"}
+fi
+
+test -z "$opt_mode" && {
+  help=$generic_help
+  func_fatal_help "you must specify a MODE"
+}
+
+test -z "$exec_cmd" && \
+  func_fatal_help "invalid operation mode '$opt_mode'"
+
+if test -n "$exec_cmd"; then
+  eval exec "$exec_cmd"
+  exit $EXIT_FAILURE
+fi
+
+exit $exit_status
+
+
+# The TAGs below are defined such that we never get into a situation
+# where we disable both kinds of libraries.  Given conflicting
+# choices, we go for a static library, that is the most portable,
+# since we can't tell whether shared libraries were disabled because
+# the user asked for that or because the platform doesn't support
+# them.  This is particularly important on AIX, because we don't
+# support having both static and shared libraries enabled at the same
+# time on that platform, so we default to a shared-only configuration.
+# If a disable-shared tag is given, we'll fallback to a static-only
+# configuration.  But we'll never go from static-only to shared-only.
+
+# ### BEGIN LIBTOOL TAG CONFIG: disable-shared
+build_libtool_libs=no
+build_old_libs=yes
+# ### END LIBTOOL TAG CONFIG: disable-shared
+
+# ### BEGIN LIBTOOL TAG CONFIG: disable-static
+build_old_libs=`case $build_libtool_libs in yes) echo no;; *) echo yes;; esac`
+# ### END LIBTOOL TAG CONFIG: disable-static
+
+# Local Variables:
+# mode:shell-script
+# sh-indentation:2
+# End:
Index: /trunk/src/libs/libpng-1.6.45/mips/filter_msa_intrinsics.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/mips/filter_msa_intrinsics.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/mips/filter_msa_intrinsics.c	(revision 107811)
@@ -0,0 +1,808 @@
+
+/* filter_msa_intrinsics.c - MSA optimised filter functions
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 2016 Glenn Randers-Pehrson
+ * Written by Mandar Sahastrabuddhe, August 2016
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include <stdio.h>
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* This code requires -mfpu=msa on the command line: */
+#if PNG_MIPS_MSA_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+#include <msa.h>
+#include <stdint.h>
+
+/* libpng row pointers are not necessarily aligned to any particular boundary,
+ * however this code will only work with appropriate alignment. mips/mips_init.c
+ * checks for this (and will not compile unless it is done). This code uses
+ * variants of png_aligncast to avoid compiler warnings.
+ */
+#define png_ptr(type,pointer) png_aligncast(type *,pointer)
+#define png_ptrc(type,pointer) png_aligncastconst(const type *,pointer)
+
+/* The following relies on a variable 'temp_pointer' being declared with type
+ * 'type'.  This is written this way just to hide the GCC strict aliasing
+ * warning; note that the code is safe because there never is an alias between
+ * the input and output pointers.
+ */
+#define png_ldr(type,pointer)\
+   (temp_pointer = png_ptr(type,pointer), *temp_pointer)
+
+#if PNG_MIPS_MSA_OPT > 0
+
+#ifdef CLANG_BUILD
+   #define MSA_SRLI_B(a, b)   __msa_srli_b((v16i8) a, b)
+
+   #define LW(psrc)                              \
+   ( {                                           \
+       uint8_t *psrc_lw_m = (uint8_t *) (psrc);  \
+       uint32_t val_m;                           \
+                                                 \
+       asm volatile (                            \
+           "lw  %[val_m],  %[psrc_lw_m]  \n\t"   \
+                                                 \
+           : [val_m] "=r" (val_m)                \
+           : [psrc_lw_m] "m" (*psrc_lw_m)        \
+       );                                        \
+                                                 \
+       val_m;                                    \
+   } )
+
+   #define SH(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sh_m = (uint8_t *) (pdst);  \
+       uint16_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "sh  %[val_m],  %[pdst_sh_m]  \n\t"   \
+                                                 \
+           : [pdst_sh_m] "=m" (*pdst_sh_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #define SW(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sw_m = (uint8_t *) (pdst);  \
+       uint32_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "sw  %[val_m],  %[pdst_sw_m]  \n\t"   \
+                                                 \
+           : [pdst_sw_m] "=m" (*pdst_sw_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+       #if (__mips == 64)
+        #define SD(val, pdst)                         \
+        {                                             \
+            uint8_t *pdst_sd_m = (uint8_t *) (pdst);  \
+            uint64_t val_m = (val);                   \
+                                                      \
+            asm volatile (                            \
+                "sd  %[val_m],  %[pdst_sd_m]  \n\t"   \
+                                                      \
+                : [pdst_sd_m] "=m" (*pdst_sd_m)       \
+                : [val_m] "r" (val_m)                 \
+            );                                        \
+        }
+    #else
+        #define SD(val, pdst)                                          \
+        {                                                              \
+            uint8_t *pdst_sd_m = (uint8_t *) (pdst);                   \
+            uint32_t val0_m, val1_m;                                   \
+                                                                       \
+            val0_m = (uint32_t) ((val) & 0x00000000FFFFFFFF);          \
+            val1_m = (uint32_t) (((val) >> 32) & 0x00000000FFFFFFFF);  \
+                                                                       \
+            SW(val0_m, pdst_sd_m);                                     \
+            SW(val1_m, pdst_sd_m + 4);                                 \
+        }
+    #endif
+#else
+   #define MSA_SRLI_B(a, b)   (a >> b)
+
+#if (__mips_isa_rev >= 6)
+   #define LW(psrc)                              \
+   ( {                                           \
+       uint8_t *psrc_lw_m = (uint8_t *) (psrc);  \
+       uint32_t val_m;                           \
+                                                 \
+       asm volatile (                            \
+           "lw  %[val_m],  %[psrc_lw_m]  \n\t"   \
+                                                 \
+           : [val_m] "=r" (val_m)                \
+           : [psrc_lw_m] "m" (*psrc_lw_m)        \
+       );                                        \
+                                                 \
+       val_m;                                    \
+   } )
+
+   #define SH(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sh_m = (uint8_t *) (pdst);  \
+       uint16_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "sh  %[val_m],  %[pdst_sh_m]  \n\t"   \
+                                                 \
+           : [pdst_sh_m] "=m" (*pdst_sh_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #define SW(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sw_m = (uint8_t *) (pdst);  \
+       uint32_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "sw  %[val_m],  %[pdst_sw_m]  \n\t"   \
+                                                 \
+           : [pdst_sw_m] "=m" (*pdst_sw_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #if (__mips == 64)
+        #define SD(val, pdst)                         \
+        {                                             \
+            uint8_t *pdst_sd_m = (uint8_t *) (pdst);  \
+            uint64_t val_m = (val);                   \
+                                                      \
+            asm volatile (                            \
+                "sd  %[val_m],  %[pdst_sd_m]  \n\t"   \
+                                                      \
+                : [pdst_sd_m] "=m" (*pdst_sd_m)       \
+                : [val_m] "r" (val_m)                 \
+            );                                        \
+        }
+    #else
+        #define SD(val, pdst)                                          \
+        {                                                              \
+            uint8_t *pdst_sd_m = (uint8_t *) (pdst);                   \
+            uint32_t val0_m, val1_m;                                   \
+                                                                       \
+            val0_m = (uint32_t) ((val) & 0x00000000FFFFFFFF);          \
+            val1_m = (uint32_t) (((val) >> 32) & 0x00000000FFFFFFFF);  \
+                                                                       \
+            SW(val0_m, pdst_sd_m);                                     \
+            SW(val1_m, pdst_sd_m + 4);                                 \
+        }
+    #endif
+#else  // !(__mips_isa_rev >= 6)
+   #define LW(psrc)                              \
+   ( {                                           \
+       uint8_t *psrc_lw_m = (uint8_t *) (psrc);  \
+       uint32_t val_m;                           \
+                                                 \
+       asm volatile (                            \
+           "ulw  %[val_m],  %[psrc_lw_m]  \n\t"  \
+                                                 \
+           : [val_m] "=r" (val_m)                \
+           : [psrc_lw_m] "m" (*psrc_lw_m)        \
+       );                                        \
+                                                 \
+       val_m;                                    \
+   } )
+
+   #define SH(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sh_m = (uint8_t *) (pdst);  \
+       uint16_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "ush  %[val_m],  %[pdst_sh_m]  \n\t"  \
+                                                 \
+           : [pdst_sh_m] "=m" (*pdst_sh_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #define SW(val, pdst)                         \
+   {                                             \
+       uint8_t *pdst_sw_m = (uint8_t *) (pdst);  \
+       uint32_t val_m = (val);                   \
+                                                 \
+       asm volatile (                            \
+           "usw  %[val_m],  %[pdst_sw_m]  \n\t"  \
+                                                 \
+           : [pdst_sw_m] "=m" (*pdst_sw_m)       \
+           : [val_m] "r" (val_m)                 \
+       );                                        \
+   }
+
+   #define SD(val, pdst)                                          \
+    {                                                              \
+        uint8_t *pdst_sd_m = (uint8_t *) (pdst);                   \
+        uint32_t val0_m, val1_m;                                   \
+                                                                   \
+        val0_m = (uint32_t) ((val) & 0x00000000FFFFFFFF);          \
+        val1_m = (uint32_t) (((val) >> 32) & 0x00000000FFFFFFFF);  \
+                                                                   \
+        SW(val0_m, pdst_sd_m);                                     \
+        SW(val1_m, pdst_sd_m + 4);                                 \
+    }
+
+    #define SW_ZERO(pdst)                      \
+    {                                          \
+        uint8_t *pdst_m = (uint8_t *) (pdst);  \
+                                               \
+        asm volatile (                         \
+            "usw  $0,  %[pdst_m]  \n\t"        \
+                                               \
+            : [pdst_m] "=m" (*pdst_m)          \
+            :                                  \
+        );                                     \
+    }
+#endif  // (__mips_isa_rev >= 6)
+#endif
+
+#define LD_B(RTYPE, psrc) *((RTYPE *) (psrc))
+#define LD_UB(...) LD_B(v16u8, __VA_ARGS__)
+#define LD_B2(RTYPE, psrc, stride, out0, out1)  \
+{                                               \
+    out0 = LD_B(RTYPE, (psrc));                 \
+    out1 = LD_B(RTYPE, (psrc) + stride);        \
+}
+#define LD_UB2(...) LD_B2(v16u8, __VA_ARGS__)
+#define LD_B4(RTYPE, psrc, stride, out0, out1, out2, out3)   \
+{                                                            \
+    LD_B2(RTYPE, (psrc), stride, out0, out1);                \
+    LD_B2(RTYPE, (psrc) + 2 * stride , stride, out2, out3);  \
+}
+#define LD_UB4(...) LD_B4(v16u8, __VA_ARGS__)
+
+#define ST_B(RTYPE, in, pdst) *((RTYPE *) (pdst)) = (in)
+#define ST_UB(...) ST_B(v16u8, __VA_ARGS__)
+#define ST_B2(RTYPE, in0, in1, pdst, stride)  \
+{                                             \
+    ST_B(RTYPE, in0, (pdst));                 \
+    ST_B(RTYPE, in1, (pdst) + stride);        \
+}
+#define ST_UB2(...) ST_B2(v16u8, __VA_ARGS__)
+#define ST_B4(RTYPE, in0, in1, in2, in3, pdst, stride)    \
+{                                                         \
+    ST_B2(RTYPE, in0, in1, (pdst), stride);               \
+    ST_B2(RTYPE, in2, in3, (pdst) + 2 * stride, stride);  \
+}
+#define ST_UB4(...) ST_B4(v16u8, __VA_ARGS__)
+
+#define ADD2(in0, in1, in2, in3, out0, out1)  \
+{                                             \
+    out0 = in0 + in1;                         \
+    out1 = in2 + in3;                         \
+}
+#define ADD3(in0, in1, in2, in3, in4, in5,  \
+             out0, out1, out2)              \
+{                                           \
+    ADD2(in0, in1, in2, in3, out0, out1);   \
+    out2 = in4 + in5;                       \
+}
+#define ADD4(in0, in1, in2, in3, in4, in5, in6, in7,  \
+             out0, out1, out2, out3)                  \
+{                                                     \
+    ADD2(in0, in1, in2, in3, out0, out1);             \
+    ADD2(in4, in5, in6, in7, out2, out3);             \
+}
+
+#define ILVR_B2(RTYPE, in0, in1, in2, in3, out0, out1)      \
+{                                                           \
+    out0 = (RTYPE) __msa_ilvr_b((v16i8) in0, (v16i8) in1);  \
+    out1 = (RTYPE) __msa_ilvr_b((v16i8) in2, (v16i8) in3);  \
+}
+#define ILVR_B2_SH(...) ILVR_B2(v8i16, __VA_ARGS__)
+
+#define HSUB_UB2(RTYPE, in0, in1, out0, out1)                 \
+{                                                             \
+    out0 = (RTYPE) __msa_hsub_u_h((v16u8) in0, (v16u8) in0);  \
+    out1 = (RTYPE) __msa_hsub_u_h((v16u8) in1, (v16u8) in1);  \
+}
+#define HSUB_UB2_SH(...) HSUB_UB2(v8i16, __VA_ARGS__)
+
+#define SLDI_B2_0(RTYPE, in0, in1, out0, out1, slide_val)                 \
+{                                                                         \
+    v16i8 zero_m = { 0 };                                                 \
+    out0 = (RTYPE) __msa_sldi_b((v16i8) zero_m, (v16i8) in0, slide_val);  \
+    out1 = (RTYPE) __msa_sldi_b((v16i8) zero_m, (v16i8) in1, slide_val);  \
+}
+#define SLDI_B2_0_UB(...) SLDI_B2_0(v16u8, __VA_ARGS__)
+
+#define SLDI_B3_0(RTYPE, in0, in1, in2, out0, out1, out2,  slide_val)     \
+{                                                                         \
+    v16i8 zero_m = { 0 };                                                 \
+    SLDI_B2_0(RTYPE, in0, in1, out0, out1, slide_val);                    \
+    out2 = (RTYPE) __msa_sldi_b((v16i8) zero_m, (v16i8) in2, slide_val);  \
+}
+#define SLDI_B3_0_UB(...) SLDI_B3_0(v16u8, __VA_ARGS__)
+
+#define ILVEV_W2(RTYPE, in0, in1, in2, in3, out0, out1)      \
+{                                                            \
+    out0 = (RTYPE) __msa_ilvev_w((v4i32) in1, (v4i32) in0);  \
+    out1 = (RTYPE) __msa_ilvev_w((v4i32) in3, (v4i32) in2);  \
+}
+#define ILVEV_W2_UB(...) ILVEV_W2(v16u8, __VA_ARGS__)
+
+#define ADD_ABS_H3(RTYPE, in0, in1, in2, out0, out1, out2)  \
+{                                                           \
+    RTYPE zero = {0};                                       \
+                                                            \
+    out0 = __msa_add_a_h((v8i16) zero, in0);                \
+    out1 = __msa_add_a_h((v8i16) zero, in1);                \
+    out2 = __msa_add_a_h((v8i16) zero, in2);                \
+}
+#define ADD_ABS_H3_SH(...) ADD_ABS_H3(v8i16, __VA_ARGS__)
+
+#define VSHF_B2(RTYPE, in0, in1, in2, in3, mask0, mask1, out0, out1)       \
+{                                                                          \
+    out0 = (RTYPE) __msa_vshf_b((v16i8) mask0, (v16i8) in1, (v16i8) in0);  \
+    out1 = (RTYPE) __msa_vshf_b((v16i8) mask1, (v16i8) in3, (v16i8) in2);  \
+}
+#define VSHF_B2_UB(...) VSHF_B2(v16u8, __VA_ARGS__)
+
+#define CMP_AND_SELECT(inp0, inp1, inp2, inp3, inp4, inp5, out0)              \
+{                                                                             \
+   v8i16 _sel_h0, _sel_h1;                                                    \
+   v16u8 _sel_b0, _sel_b1;                                                    \
+   _sel_h0 = (v8i16) __msa_clt_u_h((v8u16) inp1, (v8u16) inp0);               \
+   _sel_b0 = (v16u8) __msa_pckev_b((v16i8) _sel_h0, (v16i8) _sel_h0);         \
+   inp0 = (v8i16) __msa_bmnz_v((v16u8) inp0, (v16u8) inp1, (v16u8) _sel_h0);  \
+   inp4 = (v16u8) __msa_bmnz_v(inp3, inp4, _sel_b0);                          \
+   _sel_h1 = (v8i16) __msa_clt_u_h((v8u16) inp2, (v8u16) inp0);               \
+   _sel_b1 = (v16u8) __msa_pckev_b((v16i8) _sel_h1, (v16i8) _sel_h1);         \
+   inp4 = (v16u8) __msa_bmnz_v(inp4, inp5, _sel_b1);                          \
+   out0 += inp4;                                                              \
+}
+
+void png_read_filter_row_up_msa(png_row_infop row_info, png_bytep row,
+                                png_const_bytep prev_row)
+{
+   size_t i, cnt, cnt16, cnt32;
+   size_t istop = row_info->rowbytes;
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7;
+
+   for (i = 0; i < (istop >> 6); i++)
+   {
+      LD_UB4(rp, 16, src0, src1, src2, src3);
+      LD_UB4(pp, 16, src4, src5, src6, src7);
+      pp += 64;
+
+      ADD4(src0, src4, src1, src5, src2, src6, src3, src7,
+           src0, src1, src2, src3);
+
+      ST_UB4(src0, src1, src2, src3, rp, 16);
+      rp += 64;
+   }
+
+   if (istop & 0x3F)
+   {
+      cnt32 = istop & 0x20;
+      cnt16 = istop & 0x10;
+      cnt = istop & 0xF;
+
+      if(cnt32)
+      {
+         if (cnt16 && cnt)
+         {
+            LD_UB4(rp, 16, src0, src1, src2, src3);
+            LD_UB4(pp, 16, src4, src5, src6, src7);
+
+            ADD4(src0, src4, src1, src5, src2, src6, src3, src7,
+                 src0, src1, src2, src3);
+
+            ST_UB4(src0, src1, src2, src3, rp, 16);
+            rp += 64;
+         }
+         else if (cnt16 || cnt)
+         {
+            LD_UB2(rp, 16, src0, src1);
+            LD_UB2(pp, 16, src4, src5);
+            pp += 32;
+            src2 = LD_UB(rp + 32);
+            src6 = LD_UB(pp);
+
+            ADD3(src0, src4, src1, src5, src2, src6, src0, src1, src2);
+
+            ST_UB2(src0, src1, rp, 16);
+            rp += 32;
+            ST_UB(src2, rp);
+            rp += 16;
+         }
+         else
+         {
+            LD_UB2(rp, 16, src0, src1);
+            LD_UB2(pp, 16, src4, src5);
+
+            ADD2(src0, src4, src1, src5, src0, src1);
+
+            ST_UB2(src0, src1, rp, 16);
+            rp += 32;
+         }
+      }
+      else if (cnt16 && cnt)
+      {
+         LD_UB2(rp, 16, src0, src1);
+         LD_UB2(pp, 16, src4, src5);
+
+         ADD2(src0, src4, src1, src5, src0, src1);
+
+         ST_UB2(src0, src1, rp, 16);
+         rp += 32;
+      }
+      else if (cnt16 || cnt)
+      {
+         src0 = LD_UB(rp);
+         src4 = LD_UB(pp);
+         pp += 16;
+
+         src0 += src4;
+
+         ST_UB(src0, rp);
+         rp += 16;
+      }
+   }
+}
+
+void png_read_filter_row_sub4_msa(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   size_t count;
+   size_t istop = row_info->rowbytes;
+   png_bytep src = row;
+   png_bytep nxt = row + 4;
+   int32_t inp0;
+   v16u8 src0, src1, src2, src3, src4;
+   v16u8 dst0, dst1;
+   v16u8 zero = { 0 };
+
+   istop -= 4;
+
+   inp0 = LW(src);
+   src += 4;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+
+   for (count = 0; count < istop; count += 16)
+   {
+      src1 = LD_UB(src);
+      src += 16;
+
+      src2 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 4);
+      src3 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 8);
+      src4 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 12);
+      src1 += src0;
+      src2 += src1;
+      src3 += src2;
+      src4 += src3;
+      src0 = src4;
+      ILVEV_W2_UB(src1, src2, src3, src4, dst0, dst1);
+      dst0 = (v16u8) __msa_pckev_d((v2i64) dst1, (v2i64) dst0);
+
+      ST_UB(dst0, nxt);
+      nxt += 16;
+   }
+}
+
+void png_read_filter_row_sub3_msa(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   size_t count;
+   size_t istop = row_info->rowbytes;
+   png_bytep src = row;
+   png_bytep nxt = row + 3;
+   int64_t out0;
+   int32_t inp0, out1;
+   v16u8 src0, src1, src2, src3, src4, dst0, dst1;
+   v16u8 zero = { 0 };
+   v16i8 mask0 = { 0, 1, 2, 16, 17, 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+   v16i8 mask1 = { 0, 1, 2, 3, 4, 5, 16, 17, 18, 19, 20, 21, 0, 0, 0, 0 };
+
+   istop -= 3;
+
+   inp0 = LW(src);
+   src += 3;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+
+   for (count = 0; count < istop; count += 12)
+   {
+      src1 = LD_UB(src);
+      src += 12;
+
+      src2 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 3);
+      src3 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 6);
+      src4 = (v16u8) __msa_sldi_b((v16i8) zero, (v16i8) src1, 9);
+      src1 += src0;
+      src2 += src1;
+      src3 += src2;
+      src4 += src3;
+      src0 = src4;
+      VSHF_B2_UB(src1, src2, src3, src4, mask0, mask0, dst0, dst1);
+      dst0 = (v16u8) __msa_vshf_b(mask1, (v16i8) dst1, (v16i8) dst0);
+      out0 = __msa_copy_s_d((v2i64) dst0, 0);
+      out1 = __msa_copy_s_w((v4i32) dst0, 2);
+
+      SD(out0, nxt);
+      nxt += 8;
+      SW(out1, nxt);
+      nxt += 4;
+   }
+}
+
+void png_read_filter_row_avg4_msa(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   size_t i;
+   png_bytep src = row;
+   png_bytep nxt = row;
+   png_const_bytep pp = prev_row;
+   size_t istop = row_info->rowbytes - 4;
+   int32_t inp0, inp1, out0;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7, src8, src9, dst0, dst1;
+   v16u8 zero = { 0 };
+
+   inp0 = LW(pp);
+   pp += 4;
+   inp1 = LW(src);
+   src += 4;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+   src1 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp1);
+   src0 = (v16u8) MSA_SRLI_B(src0, 1);
+   src1 += src0;
+   out0 = __msa_copy_s_w((v4i32) src1, 0);
+   SW(out0, nxt);
+   nxt += 4;
+
+   for (i = 0; i < istop; i += 16)
+   {
+      src2 = LD_UB(pp);
+      pp += 16;
+      src6 = LD_UB(src);
+      src += 16;
+
+      SLDI_B2_0_UB(src2, src6, src3, src7, 4);
+      SLDI_B2_0_UB(src2, src6, src4, src8, 8);
+      SLDI_B2_0_UB(src2, src6, src5, src9, 12);
+      src2 = __msa_ave_u_b(src2, src1);
+      src6 += src2;
+      src3 = __msa_ave_u_b(src3, src6);
+      src7 += src3;
+      src4 = __msa_ave_u_b(src4, src7);
+      src8 += src4;
+      src5 = __msa_ave_u_b(src5, src8);
+      src9 += src5;
+      src1 = src9;
+      ILVEV_W2_UB(src6, src7, src8, src9, dst0, dst1);
+      dst0 = (v16u8) __msa_pckev_d((v2i64) dst1, (v2i64) dst0);
+
+      ST_UB(dst0, nxt);
+      nxt += 16;
+   }
+}
+
+void png_read_filter_row_avg3_msa(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   size_t i;
+   png_bytep src = row;
+   png_bytep nxt = row;
+   png_const_bytep pp = prev_row;
+   size_t istop = row_info->rowbytes - 3;
+   int64_t out0;
+   int32_t inp0, inp1, out1;
+   int16_t out2;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7, src8, src9, dst0, dst1;
+   v16u8 zero = { 0 };
+   v16i8 mask0 = { 0, 1, 2, 16, 17, 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+   v16i8 mask1 = { 0, 1, 2, 3, 4, 5, 16, 17, 18, 19, 20, 21, 0, 0, 0, 0 };
+
+   inp0 = LW(pp);
+   pp += 3;
+   inp1 = LW(src);
+   src += 3;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+   src1 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp1);
+   src0 = (v16u8) MSA_SRLI_B(src0, 1);
+   src1 += src0;
+   out2 = __msa_copy_s_h((v8i16) src1, 0);
+   SH(out2, nxt);
+   nxt += 2;
+   nxt[0] = src1[2];
+   nxt++;
+
+   for (i = 0; i < istop; i += 12)
+   {
+      src2 = LD_UB(pp);
+      pp += 12;
+      src6 = LD_UB(src);
+      src += 12;
+
+      SLDI_B2_0_UB(src2, src6, src3, src7, 3);
+      SLDI_B2_0_UB(src2, src6, src4, src8, 6);
+      SLDI_B2_0_UB(src2, src6, src5, src9, 9);
+      src2 = __msa_ave_u_b(src2, src1);
+      src6 += src2;
+      src3 = __msa_ave_u_b(src3, src6);
+      src7 += src3;
+      src4 = __msa_ave_u_b(src4, src7);
+      src8 += src4;
+      src5 = __msa_ave_u_b(src5, src8);
+      src9 += src5;
+      src1 = src9;
+      VSHF_B2_UB(src6, src7, src8, src9, mask0, mask0, dst0, dst1);
+      dst0 = (v16u8) __msa_vshf_b(mask1, (v16i8) dst1, (v16i8) dst0);
+      out0 = __msa_copy_s_d((v2i64) dst0, 0);
+      out1 = __msa_copy_s_w((v4i32) dst0, 2);
+
+      SD(out0, nxt);
+      nxt += 8;
+      SW(out1, nxt);
+      nxt += 4;
+   }
+}
+
+void png_read_filter_row_paeth4_msa(png_row_infop row_info,
+                                    png_bytep row,
+                                    png_const_bytep prev_row)
+{
+   int32_t count, rp_end;
+   png_bytep nxt;
+   png_const_bytep prev_nxt;
+   int32_t inp0, inp1, res0;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7, src8, src9;
+   v16u8 src10, src11, src12, src13, dst0, dst1;
+   v8i16 vec0, vec1, vec2;
+   v16u8 zero = { 0 };
+
+   nxt = row;
+   prev_nxt = prev_row;
+
+   inp0 = LW(nxt);
+   inp1 = LW(prev_nxt);
+   prev_nxt += 4;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+   src1 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp1);
+
+   src1 += src0;
+   res0 = __msa_copy_s_w((v4i32) src1, 0);
+
+   SW(res0, nxt);
+   nxt += 4;
+
+   /* Remainder */
+   rp_end = row_info->rowbytes - 4;
+
+   for (count = 0; count < rp_end; count += 16)
+   {
+      src2 = LD_UB(prev_nxt);
+      prev_nxt += 16;
+      src6 = LD_UB(prev_row);
+      prev_row += 16;
+      src10 = LD_UB(nxt);
+
+      SLDI_B3_0_UB(src2, src6, src10, src3, src7, src11, 4);
+      SLDI_B3_0_UB(src2, src6, src10, src4, src8, src12, 8);
+      SLDI_B3_0_UB(src2, src6, src10, src5, src9, src13, 12);
+      ILVR_B2_SH(src2, src6, src1, src6, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src1, src2, src6, src10);
+      ILVR_B2_SH(src3, src7, src10, src7, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src10, src3, src7, src11);
+      ILVR_B2_SH(src4, src8, src11, src8, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src11, src4, src8, src12);
+      ILVR_B2_SH(src5, src9, src12, src9, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src12, src5, src9, src13);
+      src1 = src13;
+      ILVEV_W2_UB(src10, src11, src12, src1, dst0, dst1);
+      dst0 = (v16u8) __msa_pckev_d((v2i64) dst1, (v2i64) dst0);
+
+      ST_UB(dst0, nxt);
+      nxt += 16;
+   }
+}
+
+void png_read_filter_row_paeth3_msa(png_row_infop row_info,
+                                    png_bytep row,
+                                    png_const_bytep prev_row)
+{
+   int32_t count, rp_end;
+   png_bytep nxt;
+   png_const_bytep prev_nxt;
+   int64_t out0;
+   int32_t inp0, inp1, out1;
+   int16_t out2;
+   v16u8 src0, src1, src2, src3, src4, src5, src6, src7, src8, src9, dst0, dst1;
+   v16u8 src10, src11, src12, src13;
+   v8i16 vec0, vec1, vec2;
+   v16u8 zero = { 0 };
+   v16i8 mask0 = { 0, 1, 2, 16, 17, 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+   v16i8 mask1 = { 0, 1, 2, 3, 4, 5, 16, 17, 18, 19, 20, 21, 0, 0, 0, 0 };
+
+   nxt = row;
+   prev_nxt = prev_row;
+
+   inp0 = LW(nxt);
+   inp1 = LW(prev_nxt);
+   prev_nxt += 3;
+   src0 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp0);
+   src1 = (v16u8) __msa_insert_w((v4i32) zero, 0, inp1);
+
+   src1 += src0;
+   out2 = __msa_copy_s_h((v8i16) src1, 0);
+
+   SH(out2, nxt);
+   nxt += 2;
+   nxt[0] = src1[2];
+   nxt++;
+
+   /* Remainder */
+   rp_end = row_info->rowbytes - 3;
+
+   for (count = 0; count < rp_end; count += 12)
+   {
+      src2 = LD_UB(prev_nxt);
+      prev_nxt += 12;
+      src6 = LD_UB(prev_row);
+      prev_row += 12;
+      src10 = LD_UB(nxt);
+
+      SLDI_B3_0_UB(src2, src6, src10, src3, src7, src11, 3);
+      SLDI_B3_0_UB(src2, src6, src10, src4, src8, src12, 6);
+      SLDI_B3_0_UB(src2, src6, src10, src5, src9, src13, 9);
+      ILVR_B2_SH(src2, src6, src1, src6, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src1, src2, src6, src10);
+      ILVR_B2_SH(src3, src7, src10, src7, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src10, src3, src7, src11);
+      ILVR_B2_SH(src4, src8, src11, src8, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src11, src4, src8, src12);
+      ILVR_B2_SH(src5, src9, src12, src9, vec0, vec1);
+      HSUB_UB2_SH(vec0, vec1, vec0, vec1);
+      vec2 = vec0 + vec1;
+      ADD_ABS_H3_SH(vec0, vec1, vec2, vec0, vec1, vec2);
+      CMP_AND_SELECT(vec0, vec1, vec2, src12, src5, src9, src13);
+      src1 = src13;
+      VSHF_B2_UB(src10, src11, src12, src13, mask0, mask0, dst0, dst1);
+      dst0 = (v16u8) __msa_vshf_b(mask1, (v16i8) dst1, (v16i8) dst0);
+      out0 = __msa_copy_s_d((v2i64) dst0, 0);
+      out1 = __msa_copy_s_w((v4i32) dst0, 2);
+
+      SD(out0, nxt);
+      nxt += 8;
+      SW(out1, nxt);
+      nxt += 4;
+   }
+}
+
+#endif /* PNG_MIPS_MSA_OPT > 0 */
+#endif /* PNG_MIPS_MSA_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/mips/mips_init.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/mips/mips_init.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/mips/mips_init.c	(revision 107811)
@@ -0,0 +1,204 @@
+
+/* mips_init.c - MSA optimised filter functions
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 2016 Glenn Randers-Pehrson
+ * Written by Mandar Sahastrabuddhe, 2016
+ * Updated by guxiwei, 2023
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
+ * called.
+ */
+#define _POSIX_SOURCE 1
+
+#include <stdio.h>
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_MIPS_MSA_IMPLEMENTATION == 1 || PNG_MIPS_MMI_IMPLEMENTATION > 0
+
+#ifdef PNG_MIPS_MSA_CHECK_SUPPORTED /* Do MIPS MSA run-time checks */
+/* WARNING: it is strongly recommended that you do not build libpng with
+ * run-time checks for CPU features if at all possible.  In the case of the MIPS
+ * MSA instructions there is no processor-specific way of detecting the
+ * presence of the required support, therefore run-time detection is extremely
+ * OS specific.
+ *
+ * You may set the macro PNG_MIPS_MSA_FILE to the file name of file containing
+ * a fragment of C source code which defines the png_have_msa function.  There
+ * are a number of implementations in contrib/mips-msa, but the only one that
+ * has partial support is contrib/mips-msa/linux.c - a generic Linux
+ * implementation which reads /proc/cpufino.
+ */
+#ifndef PNG_MIPS_MSA_FILE
+#  ifdef __linux__
+#     define PNG_MIPS_MSA_FILE "contrib/mips-msa/linux.c"
+#  endif
+#endif
+
+#ifdef PNG_MIPS_MSA_FILE
+
+#include <signal.h> /* for sig_atomic_t */
+static int png_have_msa(png_structp png_ptr);
+#include PNG_MIPS_MSA_FILE
+
+#else  /* PNG_MIPS_MSA_FILE */
+#  error "PNG_MIPS_MSA_FILE undefined: no support for run-time MIPS MSA checks"
+#endif /* PNG_MIPS_MSA_FILE */
+#endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
+
+#ifdef PNG_MIPS_MMI_CHECK_SUPPORTED /* Do MIPS MMI run-times checks */
+#ifndef PNG_MIPS_MMI_FILE
+#  ifdef __linux__
+#     define PNG_MIPS_MMI_FILE "contrib/mips-mmi/linux.c"
+#  endif
+#endif
+
+#ifdef PNG_MIPS_MMI_FILE
+
+#include <signal.h> /* for sig_atomic_t */
+static int png_have_mmi();
+#include PNG_MIPS_MMI_FILE
+
+#else  /* PNG_MIPS_MMI_FILE */
+#  error "PNG_MIPS_MMI_FILE undefined: no support for run-time MIPS MMI checks"
+#endif /* PNG_MIPS_MMI_FILE */
+#endif /* PNG_MIPS_MMI_CHECK_SUPPORTED*/
+
+#ifndef PNG_ALIGNED_MEMORY_SUPPORTED
+#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#endif
+
+/* MIPS supports two optimizations: MMI and MSA. The appropriate
+ * optimization is chosen at runtime
+ */
+void
+png_init_filter_functions_mips(png_structp pp, unsigned int bpp)
+{
+#if PNG_MIPS_MMI_IMPLEMENTATION  > 0
+#ifdef PNG_MIPS_MMI_API_SUPPORTED
+   switch ((pp->options >> PNG_MIPS_MMI) & 3)
+   {
+      case PNG_OPTION_UNSET:
+#endif /* PNG_MIPS_MMI_API_SUPPORTED */
+#ifdef PNG_MIPS_MMI_CHECK_SUPPORTED
+         {
+            static volatile sig_atomic_t no_mmi = -1; /* not checked */
+
+            if (no_mmi < 0)
+               no_mmi = !png_have_mmi();
+
+            if (no_mmi)
+              goto MIPS_MSA_INIT;
+         }
+#ifdef PNG_MIPS_MMI_API_SUPPORTED
+         break;
+#endif
+#endif /* PNG_MIPS_MMI_CHECK_SUPPORTED */
+
+#ifdef PNG_MIPS_MMI_API_SUPPORTED
+      default: /* OFF or INVALID */
+         goto MIPS_MSA_INIT;
+
+      case PNG_OPTION_ON:
+         /* Option turned on */
+         break;
+   }
+#endif
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_mmi;
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_mmi;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_mmi;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth3_mmi;
+   }
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_mmi;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_mmi;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+          png_read_filter_row_paeth4_mmi;
+   }
+#endif /* PNG_MIPS_MMI_IMPLEMENTATION > 0 */
+
+MIPS_MSA_INIT:
+#if PNG_MIPS_MSA_IMPLEMENTATION == 1
+   /* The switch statement is compiled in for MIPS_MSA_API, the call to
+    * png_have_msa is compiled in for MIPS_MSA_CHECK. If both are defined
+    * the check is only performed if the API has not set the MSA option on
+    * or off explicitly. In this case the check controls what happens.
+    */
+
+#ifdef PNG_MIPS_MSA_API_SUPPORTED
+   switch ((pp->options >> PNG_MIPS_MSA) & 3)
+   {
+      case PNG_OPTION_UNSET:
+         /* Allow the run-time check to execute if it has been enabled -
+          * thus both API and CHECK can be turned on.  If it isn't supported
+          * this case will fall through to the 'default' below, which just
+          * returns.
+          */
+#endif /* PNG_MIPS_MSA_API_SUPPORTED */
+#ifdef PNG_MIPS_MSA_CHECK_SUPPORTED
+         {
+            static volatile sig_atomic_t no_msa = -1; /* not checked */
+
+            if (no_msa < 0)
+               no_msa = !png_have_msa(pp);
+
+            if (no_msa)
+               return;
+         }
+#ifdef PNG_MIPS_MSA_API_SUPPORTED
+         break;
+#endif
+#endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
+
+#ifdef PNG_MIPS_MSA_API_SUPPORTED
+      default: /* OFF or INVALID */
+         return;
+
+      case PNG_OPTION_ON:
+         /* Option turned on */
+         break;
+   }
+#endif
+
+   /* IMPORTANT: any new external functions used here must be declared using
+    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
+    * 'prefix' option to configure works:
+    *
+    *    ./configure --with-libpng-prefix=foobar_
+    *
+    * Verify you have got this right by running the above command, doing a build
+    * and examining pngprefix.h; it must contain a #define for every external
+    * function you add.  (Notice that this happens automatically for the
+    * initialization function.)
+    */
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_msa;
+
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_msa;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_msa;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_msa;
+   }
+
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_msa;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_msa;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_msa;
+   }
+#endif /* PNG_MIPS_MSA_IMPLEMENTATION == 1 */
+   return;
+}
+#endif /* PNG_MIPS_MSA_IMPLEMENTATION == 1 || PNG_MIPS_MMI_IMPLEMENTATION > 0 */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/missing
===================================================================
--- /trunk/src/libs/libpng-1.6.45/missing	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/missing	(revision 107811)
@@ -0,0 +1,215 @@
+#! /bin/sh
+# Common wrapper for a few potentially missing GNU programs.
+
+scriptversion=2018-03-07.03; # UTC
+
+# Copyright (C) 1996-2021 Free Software Foundation, Inc.
+# Originally written by Fran,cois Pinard <pinard@iro.umontreal.ca>, 1996.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+if test $# -eq 0; then
+  echo 1>&2 "Try '$0 --help' for more information"
+  exit 1
+fi
+
+case $1 in
+
+  --is-lightweight)
+    # Used by our autoconf macros to check whether the available missing
+    # script is modern enough.
+    exit 0
+    ;;
+
+  --run)
+    # Back-compat with the calling convention used by older automake.
+    shift
+    ;;
+
+  -h|--h|--he|--hel|--help)
+    echo "\
+$0 [OPTION]... PROGRAM [ARGUMENT]...
+
+Run 'PROGRAM [ARGUMENT]...', returning a proper advice when this fails due
+to PROGRAM being missing or too old.
+
+Options:
+  -h, --help      display this help and exit
+  -v, --version   output version information and exit
+
+Supported PROGRAM values:
+  aclocal   autoconf  autoheader   autom4te  automake  makeinfo
+  bison     yacc      flex         lex       help2man
+
+Version suffixes to PROGRAM as well as the prefixes 'gnu-', 'gnu', and
+'g' are ignored when checking the name.
+
+Send bug reports to <bug-automake@gnu.org>."
+    exit $?
+    ;;
+
+  -v|--v|--ve|--ver|--vers|--versi|--versio|--version)
+    echo "missing $scriptversion (GNU Automake)"
+    exit $?
+    ;;
+
+  -*)
+    echo 1>&2 "$0: unknown '$1' option"
+    echo 1>&2 "Try '$0 --help' for more information"
+    exit 1
+    ;;
+
+esac
+
+# Run the given program, remember its exit status.
+"$@"; st=$?
+
+# If it succeeded, we are done.
+test $st -eq 0 && exit 0
+
+# Also exit now if we it failed (or wasn't found), and '--version' was
+# passed; such an option is passed most likely to detect whether the
+# program is present and works.
+case $2 in --version|--help) exit $st;; esac
+
+# Exit code 63 means version mismatch.  This often happens when the user
+# tries to use an ancient version of a tool on a file that requires a
+# minimum version.
+if test $st -eq 63; then
+  msg="probably too old"
+elif test $st -eq 127; then
+  # Program was missing.
+  msg="missing on your system"
+else
+  # Program was found and executed, but failed.  Give up.
+  exit $st
+fi
+
+perl_URL=https://www.perl.org/
+flex_URL=https://github.com/westes/flex
+gnu_software_URL=https://www.gnu.org/software
+
+program_details ()
+{
+  case $1 in
+    aclocal|automake)
+      echo "The '$1' program is part of the GNU Automake package:"
+      echo "<$gnu_software_URL/automake>"
+      echo "It also requires GNU Autoconf, GNU m4 and Perl in order to run:"
+      echo "<$gnu_software_URL/autoconf>"
+      echo "<$gnu_software_URL/m4/>"
+      echo "<$perl_URL>"
+      ;;
+    autoconf|autom4te|autoheader)
+      echo "The '$1' program is part of the GNU Autoconf package:"
+      echo "<$gnu_software_URL/autoconf/>"
+      echo "It also requires GNU m4 and Perl in order to run:"
+      echo "<$gnu_software_URL/m4/>"
+      echo "<$perl_URL>"
+      ;;
+  esac
+}
+
+give_advice ()
+{
+  # Normalize program name to check for.
+  normalized_program=`echo "$1" | sed '
+    s/^gnu-//; t
+    s/^gnu//; t
+    s/^g//; t'`
+
+  printf '%s\n' "'$1' is $msg."
+
+  configure_deps="'configure.ac' or m4 files included by 'configure.ac'"
+  case $normalized_program in
+    autoconf*)
+      echo "You should only need it if you modified 'configure.ac',"
+      echo "or m4 files included by it."
+      program_details 'autoconf'
+      ;;
+    autoheader*)
+      echo "You should only need it if you modified 'acconfig.h' or"
+      echo "$configure_deps."
+      program_details 'autoheader'
+      ;;
+    automake*)
+      echo "You should only need it if you modified 'Makefile.am' or"
+      echo "$configure_deps."
+      program_details 'automake'
+      ;;
+    aclocal*)
+      echo "You should only need it if you modified 'acinclude.m4' or"
+      echo "$configure_deps."
+      program_details 'aclocal'
+      ;;
+   autom4te*)
+      echo "You might have modified some maintainer files that require"
+      echo "the 'autom4te' program to be rebuilt."
+      program_details 'autom4te'
+      ;;
+    bison*|yacc*)
+      echo "You should only need it if you modified a '.y' file."
+      echo "You may want to install the GNU Bison package:"
+      echo "<$gnu_software_URL/bison/>"
+      ;;
+    lex*|flex*)
+      echo "You should only need it if you modified a '.l' file."
+      echo "You may want to install the Fast Lexical Analyzer package:"
+      echo "<$flex_URL>"
+      ;;
+    help2man*)
+      echo "You should only need it if you modified a dependency" \
+           "of a man page."
+      echo "You may want to install the GNU Help2man package:"
+      echo "<$gnu_software_URL/help2man/>"
+    ;;
+    makeinfo*)
+      echo "You should only need it if you modified a '.texi' file, or"
+      echo "any other file indirectly affecting the aspect of the manual."
+      echo "You might want to install the Texinfo package:"
+      echo "<$gnu_software_URL/texinfo/>"
+      echo "The spurious makeinfo call might also be the consequence of"
+      echo "using a buggy 'make' (AIX, DU, IRIX), in which case you might"
+      echo "want to install GNU make:"
+      echo "<$gnu_software_URL/make/>"
+      ;;
+    *)
+      echo "You might have modified some files without having the proper"
+      echo "tools for further handling them.  Check the 'README' file, it"
+      echo "often tells you about the needed prerequisites for installing"
+      echo "this package.  You may also peek at any GNU archive site, in"
+      echo "case some other package contains this missing '$1' program."
+      ;;
+  esac
+}
+
+give_advice "$1" | sed -e '1s/^/WARNING: /' \
+                       -e '2,$s/^/         /' >&2
+
+# Propagate the correct exit status (expected to be 127 for a program
+# not found, 63 for a program that failed due to version mismatch).
+exit $st
+
+# Local variables:
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
Index: /trunk/src/libs/libpng-1.6.45/png.5
===================================================================
--- /trunk/src/libs/libpng-1.6.45/png.5	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/png.5	(revision 107811)
@@ -0,0 +1,59 @@
+.TH PNG 5 "February 23, 2024"
+.SH NAME
+png \- Portable Network Graphics (PNG) format
+
+.SH DESCRIPTION
+PNG (Portable Network Graphics) is an extensible file format for the
+lossless, portable, well-compressed storage of raster images.  PNG
+provides a patent-free replacement for GIF, and can also replace many
+common uses of TIFF. Indexed-color, grayscale, and truecolor images are
+supported, plus an optional alpha channel.  Sample depths range from
+1 to 16 bits.
+.br
+PNG is designed to work well in online viewing applications, such
+as the World Wide Web, so it is fully streamable with a progressive
+display option.  PNG is robust, providing both full file integrity
+checking and fast, simple detection of common transmission errors.
+Also, PNG can store gamma and chromaticity data for improved color
+matching on heterogeneous platforms.
+
+.SH "SEE ALSO"
+.BR "libpng"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
+.LP
+PNG Specification (Second Edition), November 2003:
+.IP
+.br
+https://www.w3.org/TR/2003/REC-PNG-20031110/
+.LP
+PNG 1.2 Specification, July 1999:
+.IP
+.br
+https://png-mng.sourceforge.io/pub/png/spec/1.2/
+.LP
+PNG 1.0 Specification, October 1996:
+.IP
+.br
+RFC 2083
+.br
+https://www.ietf.org/rfc/rfc2083.txt
+.IP
+.br
+or W3C Recommendation
+.br
+https://www.w3.org/TR/REC-png-961001
+
+.SH AUTHORS
+This man page: Glenn Randers-Pehrson, Cosmin Truta
+.LP
+Portable Network Graphics (PNG) Specification (Second Edition)
+Information technology - Computer graphics and image processing -
+Portable Network Graphics (PNG): Functional specification.
+ISO/IEC 15948:2003 (E) (November 10, 2003): David Duce and others.
+.LP
+Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999):
+Glenn Randers-Pehrson and others.
+.LP
+Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996):
+Thomas Boutell and others.
+
+.\" end of man page
Index: /trunk/src/libs/libpng-1.6.45/png.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/png.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/png.c	(revision 107811)
@@ -0,0 +1,4559 @@
+
+/* png.c - location for general purpose libpng functions
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+/* Generate a compiler error if there is an old png.h in the search path. */
+typedef png_libpng_version_1_6_43 Your_png_h_is_not_version_1_6_43;
+
+/* Tells libpng that we have already handled the first "num_bytes" bytes
+ * of the PNG file signature.  If the PNG data is embedded into another
+ * stream we can set num_bytes = 8 so that libpng will not attempt to read
+ * or write any of the magic bytes before it starts on the IHDR.
+ */
+
+#ifdef PNG_READ_SUPPORTED
+void PNGAPI
+png_set_sig_bytes(png_structrp png_ptr, int num_bytes)
+{
+   unsigned int nb = (unsigned int)num_bytes;
+
+   png_debug(1, "in png_set_sig_bytes");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (num_bytes < 0)
+      nb = 0;
+
+   if (nb > 8)
+      png_error(png_ptr, "Too many bytes for PNG signature");
+
+   png_ptr->sig_bytes = (png_byte)nb;
+}
+
+/* Checks whether the supplied bytes match the PNG signature.  We allow
+ * checking less than the full 8-byte signature so that those apps that
+ * already read the first few bytes of a file to determine the file type
+ * can simply check the remaining bytes for extra assurance.  Returns
+ * an integer less than, equal to, or greater than zero if sig is found,
+ * respectively, to be less than, to match, or be greater than the correct
+ * PNG signature (this is the same behavior as strcmp, memcmp, etc).
+ */
+int PNGAPI
+png_sig_cmp(png_const_bytep sig, size_t start, size_t num_to_check)
+{
+   static const png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+
+   if (num_to_check > 8)
+      num_to_check = 8;
+
+   else if (num_to_check < 1)
+      return -1;
+
+   if (start > 7)
+      return -1;
+
+   if (start + num_to_check > 8)
+      num_to_check = 8 - start;
+
+   return memcmp(&sig[start], &png_signature[start], num_to_check);
+}
+
+#endif /* READ */
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Function to allocate memory for zlib */
+PNG_FUNCTION(voidpf /* PRIVATE */,
+png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
+{
+   png_alloc_size_t num_bytes = size;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   if (items >= (~(png_alloc_size_t)0)/size)
+   {
+      png_warning (png_voidcast(png_structrp, png_ptr),
+          "Potential overflow in png_zalloc()");
+      return NULL;
+   }
+
+   num_bytes *= items;
+   return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes);
+}
+
+/* Function to free memory for zlib */
+void /* PRIVATE */
+png_zfree(voidpf png_ptr, voidpf ptr)
+{
+   png_free(png_voidcast(png_const_structrp,png_ptr), ptr);
+}
+
+/* Reset the CRC variable to 32 bits of 1's.  Care must be taken
+ * in case CRC is > 32 bits to leave the top bits 0.
+ */
+void /* PRIVATE */
+png_reset_crc(png_structrp png_ptr)
+{
+   /* The cast is safe because the crc is a 32-bit value. */
+   png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
+}
+
+/* Calculate the CRC over a section of data.  We can only pass as
+ * much data to this routine as the largest single buffer size.  We
+ * also check that this data will actually be used before going to the
+ * trouble of calculating it.
+ */
+void /* PRIVATE */
+png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, size_t length)
+{
+   int need_crc = 1;
+
+   if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
+          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
+         need_crc = 0;
+   }
+
+   else /* critical */
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
+         need_crc = 0;
+   }
+
+   /* 'uLong' is defined in zlib.h as unsigned long; this means that on some
+    * systems it is a 64-bit value.  crc32, however, returns 32 bits so the
+    * following cast is safe.  'uInt' may be no more than 16 bits, so it is
+    * necessary to perform a loop here.
+    */
+   if (need_crc != 0 && length > 0)
+   {
+      uLong crc = png_ptr->crc; /* Should never issue a warning */
+
+      do
+      {
+         uInt safe_length = (uInt)length;
+#ifndef __COVERITY__
+         if (safe_length == 0)
+            safe_length = (uInt)-1; /* evil, but safe */
+#endif
+
+         crc = crc32(crc, ptr, safe_length);
+
+         /* The following should never issue compiler warnings; if they do the
+          * target system has characteristics that will probably violate other
+          * assumptions within the libpng code.
+          */
+         ptr += safe_length;
+         length -= safe_length;
+      }
+      while (length > 0);
+
+      /* And the following is always safe because the crc is only 32 bits. */
+      png_ptr->crc = (png_uint_32)crc;
+   }
+}
+
+/* Check a user supplied version number, called from both read and write
+ * functions that create a png_struct.
+ */
+int
+png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
+{
+   /* Libpng versions 1.0.0 and later are binary compatible if the version
+    * string matches through the second '.'; we must recompile any
+    * applications that use any older library version.
+    */
+
+   if (user_png_ver != NULL)
+   {
+      int i = -1;
+      int found_dots = 0;
+
+      do
+      {
+         i++;
+         if (user_png_ver[i] != PNG_LIBPNG_VER_STRING[i])
+            png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+         if (user_png_ver[i] == '.')
+            found_dots++;
+      } while (found_dots < 2 && user_png_ver[i] != 0 &&
+            PNG_LIBPNG_VER_STRING[i] != 0);
+   }
+
+   else
+      png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+
+   if ((png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) != 0)
+   {
+#ifdef PNG_WARNINGS_SUPPORTED
+      size_t pos = 0;
+      char m[128];
+
+      pos = png_safecat(m, (sizeof m), pos,
+          "Application built with libpng-");
+      pos = png_safecat(m, (sizeof m), pos, user_png_ver);
+      pos = png_safecat(m, (sizeof m), pos, " but running with ");
+      pos = png_safecat(m, (sizeof m), pos, PNG_LIBPNG_VER_STRING);
+      PNG_UNUSED(pos)
+
+      png_warning(png_ptr, m);
+#endif
+
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+      png_ptr->flags = 0;
+#endif
+
+      return 0;
+   }
+
+   /* Success return. */
+   return 1;
+}
+
+/* Generic function to create a png_struct for either read or write - this
+ * contains the common initialization.
+ */
+PNG_FUNCTION(png_structp /* PRIVATE */,
+png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
+{
+   png_struct create_struct;
+#  ifdef PNG_SETJMP_SUPPORTED
+      jmp_buf create_jmp_buf;
+#  endif
+
+   /* This temporary stack-allocated structure is used to provide a place to
+    * build enough context to allow the user provided memory allocator (if any)
+    * to be called.
+    */
+   memset(&create_struct, 0, (sizeof create_struct));
+
+   /* Added at libpng-1.2.6 */
+#  ifdef PNG_USER_LIMITS_SUPPORTED
+      create_struct.user_width_max = PNG_USER_WIDTH_MAX;
+      create_struct.user_height_max = PNG_USER_HEIGHT_MAX;
+
+#     ifdef PNG_USER_CHUNK_CACHE_MAX
+      /* Added at libpng-1.2.43 and 1.4.0 */
+      create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
+#     endif
+
+#     ifdef PNG_USER_CHUNK_MALLOC_MAX
+      /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists
+       * in png_struct regardless.
+       */
+      create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
+#     endif
+#  endif
+
+   /* The following two API calls simply set fields in png_struct, so it is safe
+    * to do them now even though error handling is not yet set up.
+    */
+#  ifdef PNG_USER_MEM_SUPPORTED
+      png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn);
+#  else
+      PNG_UNUSED(mem_ptr)
+      PNG_UNUSED(malloc_fn)
+      PNG_UNUSED(free_fn)
+#  endif
+
+   /* (*error_fn) can return control to the caller after the error_ptr is set,
+    * this will result in a memory leak unless the error_fn does something
+    * extremely sophisticated.  The design lacks merit but is implicit in the
+    * API.
+    */
+   png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn);
+
+#  ifdef PNG_SETJMP_SUPPORTED
+      if (!setjmp(create_jmp_buf))
+#  endif
+      {
+#  ifdef PNG_SETJMP_SUPPORTED
+         /* Temporarily fake out the longjmp information until we have
+          * successfully completed this function.  This only works if we have
+          * setjmp() support compiled in, but it is safe - this stuff should
+          * never happen.
+          */
+         create_struct.jmp_buf_ptr = &create_jmp_buf;
+         create_struct.jmp_buf_size = 0; /*stack allocation*/
+         create_struct.longjmp_fn = longjmp;
+#  endif
+         /* Call the general version checker (shared with read and write code):
+          */
+         if (png_user_version_check(&create_struct, user_png_ver) != 0)
+         {
+            png_structrp png_ptr = png_voidcast(png_structrp,
+                png_malloc_warn(&create_struct, (sizeof *png_ptr)));
+
+            if (png_ptr != NULL)
+            {
+               /* png_ptr->zstream holds a back-pointer to the png_struct, so
+                * this can only be done now:
+                */
+               create_struct.zstream.zalloc = png_zalloc;
+               create_struct.zstream.zfree = png_zfree;
+               create_struct.zstream.opaque = png_ptr;
+
+#              ifdef PNG_SETJMP_SUPPORTED
+               /* Eliminate the local error handling: */
+               create_struct.jmp_buf_ptr = NULL;
+               create_struct.jmp_buf_size = 0;
+               create_struct.longjmp_fn = 0;
+#              endif
+
+               *png_ptr = create_struct;
+
+               /* This is the successful return point */
+               return png_ptr;
+            }
+         }
+      }
+
+   /* A longjmp because of a bug in the application storage allocator or a
+    * simple failure to allocate the png_struct.
+    */
+   return NULL;
+}
+
+/* Allocate the memory for an info_struct for the application. */
+PNG_FUNCTION(png_infop,PNGAPI
+png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED)
+{
+   png_inforp info_ptr;
+
+   png_debug(1, "in png_create_info_struct");
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   /* Use the internal API that does not (or at least should not) error out, so
+    * that this call always returns ok.  The application typically sets up the
+    * error handling *after* creating the info_struct because this is the way it
+    * has always been done in 'example.c'.
+    */
+   info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr,
+       (sizeof *info_ptr)));
+
+   if (info_ptr != NULL)
+      memset(info_ptr, 0, (sizeof *info_ptr));
+
+   return info_ptr;
+}
+
+/* This function frees the memory associated with a single info struct.
+ * Normally, one would use either png_destroy_read_struct() or
+ * png_destroy_write_struct() to free an info struct, but this may be
+ * useful for some applications.  From libpng 1.6.0 this function is also used
+ * internally to implement the png_info release part of the 'struct' destroy
+ * APIs.  This ensures that all possible approaches free the same data (all of
+ * it).
+ */
+void PNGAPI
+png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr)
+{
+   png_inforp info_ptr = NULL;
+
+   png_debug(1, "in png_destroy_info_struct");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (info_ptr_ptr != NULL)
+      info_ptr = *info_ptr_ptr;
+
+   if (info_ptr != NULL)
+   {
+      /* Do this first in case of an error below; if the app implements its own
+       * memory management this can lead to png_free calling png_error, which
+       * will abort this routine and return control to the app error handler.
+       * An infinite loop may result if it then tries to free the same info
+       * ptr.
+       */
+      *info_ptr_ptr = NULL;
+
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
+      memset(info_ptr, 0, (sizeof *info_ptr));
+      png_free(png_ptr, info_ptr);
+   }
+}
+
+/* Initialize the info structure.  This is now an internal function (0.89)
+ * and applications using it are urged to use png_create_info_struct()
+ * instead.  Use deprecated in 1.6.0, internal use removed (used internally it
+ * is just a memset).
+ *
+ * NOTE: it is almost inconceivable that this API is used because it bypasses
+ * the user-memory mechanism and the user error handling/warning mechanisms in
+ * those cases where it does anything other than a memset.
+ */
+PNG_FUNCTION(void,PNGAPI
+png_info_init_3,(png_infopp ptr_ptr, size_t png_info_struct_size),
+    PNG_DEPRECATED)
+{
+   png_inforp info_ptr = *ptr_ptr;
+
+   png_debug(1, "in png_info_init_3");
+
+   if (info_ptr == NULL)
+      return;
+
+   if ((sizeof (png_info)) > png_info_struct_size)
+   {
+      *ptr_ptr = NULL;
+      /* The following line is why this API should not be used: */
+      free(info_ptr);
+      info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL,
+          (sizeof *info_ptr)));
+      if (info_ptr == NULL)
+         return;
+      *ptr_ptr = info_ptr;
+   }
+
+   /* Set everything to 0 */
+   memset(info_ptr, 0, (sizeof *info_ptr));
+}
+
+void PNGAPI
+png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr,
+    int freer, png_uint_32 mask)
+{
+   png_debug(1, "in png_data_freer");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (freer == PNG_DESTROY_WILL_FREE_DATA)
+      info_ptr->free_me |= mask;
+
+   else if (freer == PNG_USER_WILL_FREE_DATA)
+      info_ptr->free_me &= ~mask;
+
+   else
+      png_error(png_ptr, "Unknown freer parameter in png_data_freer");
+}
+
+void PNGAPI
+png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
+    int num)
+{
+   png_debug(1, "in png_free_data");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+#ifdef PNG_TEXT_SUPPORTED
+   /* Free text item num or (if num == -1) all text items */
+   if (info_ptr->text != NULL &&
+       ((mask & PNG_FREE_TEXT) & info_ptr->free_me) != 0)
+   {
+      if (num != -1)
+      {
+         png_free(png_ptr, info_ptr->text[num].key);
+         info_ptr->text[num].key = NULL;
+      }
+
+      else
+      {
+         int i;
+
+         for (i = 0; i < info_ptr->num_text; i++)
+            png_free(png_ptr, info_ptr->text[i].key);
+
+         png_free(png_ptr, info_ptr->text);
+         info_ptr->text = NULL;
+         info_ptr->num_text = 0;
+         info_ptr->max_text = 0;
+      }
+   }
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+   /* Free any tRNS entry */
+   if (((mask & PNG_FREE_TRNS) & info_ptr->free_me) != 0)
+   {
+      info_ptr->valid &= ~PNG_INFO_tRNS;
+      png_free(png_ptr, info_ptr->trans_alpha);
+      info_ptr->trans_alpha = NULL;
+      info_ptr->num_trans = 0;
+   }
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+   /* Free any sCAL entry */
+   if (((mask & PNG_FREE_SCAL) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->scal_s_width);
+      png_free(png_ptr, info_ptr->scal_s_height);
+      info_ptr->scal_s_width = NULL;
+      info_ptr->scal_s_height = NULL;
+      info_ptr->valid &= ~PNG_INFO_sCAL;
+   }
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+   /* Free any pCAL entry */
+   if (((mask & PNG_FREE_PCAL) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->pcal_purpose);
+      png_free(png_ptr, info_ptr->pcal_units);
+      info_ptr->pcal_purpose = NULL;
+      info_ptr->pcal_units = NULL;
+
+      if (info_ptr->pcal_params != NULL)
+         {
+            int i;
+
+            for (i = 0; i < info_ptr->pcal_nparams; i++)
+               png_free(png_ptr, info_ptr->pcal_params[i]);
+
+            png_free(png_ptr, info_ptr->pcal_params);
+            info_ptr->pcal_params = NULL;
+         }
+      info_ptr->valid &= ~PNG_INFO_pCAL;
+   }
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+   /* Free any profile entry */
+   if (((mask & PNG_FREE_ICCP) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->iccp_name);
+      png_free(png_ptr, info_ptr->iccp_profile);
+      info_ptr->iccp_name = NULL;
+      info_ptr->iccp_profile = NULL;
+      info_ptr->valid &= ~PNG_INFO_iCCP;
+   }
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+   /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
+   if (info_ptr->splt_palettes != NULL &&
+       ((mask & PNG_FREE_SPLT) & info_ptr->free_me) != 0)
+   {
+      if (num != -1)
+      {
+         png_free(png_ptr, info_ptr->splt_palettes[num].name);
+         png_free(png_ptr, info_ptr->splt_palettes[num].entries);
+         info_ptr->splt_palettes[num].name = NULL;
+         info_ptr->splt_palettes[num].entries = NULL;
+      }
+
+      else
+      {
+         int i;
+
+         for (i = 0; i < info_ptr->splt_palettes_num; i++)
+         {
+            png_free(png_ptr, info_ptr->splt_palettes[i].name);
+            png_free(png_ptr, info_ptr->splt_palettes[i].entries);
+         }
+
+         png_free(png_ptr, info_ptr->splt_palettes);
+         info_ptr->splt_palettes = NULL;
+         info_ptr->splt_palettes_num = 0;
+         info_ptr->valid &= ~PNG_INFO_sPLT;
+      }
+   }
+#endif
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+   if (info_ptr->unknown_chunks != NULL &&
+       ((mask & PNG_FREE_UNKN) & info_ptr->free_me) != 0)
+   {
+      if (num != -1)
+      {
+          png_free(png_ptr, info_ptr->unknown_chunks[num].data);
+          info_ptr->unknown_chunks[num].data = NULL;
+      }
+
+      else
+      {
+         int i;
+
+         for (i = 0; i < info_ptr->unknown_chunks_num; i++)
+            png_free(png_ptr, info_ptr->unknown_chunks[i].data);
+
+         png_free(png_ptr, info_ptr->unknown_chunks);
+         info_ptr->unknown_chunks = NULL;
+         info_ptr->unknown_chunks_num = 0;
+      }
+   }
+#endif
+
+#ifdef PNG_eXIf_SUPPORTED
+   /* Free any eXIf entry */
+   if (((mask & PNG_FREE_EXIF) & info_ptr->free_me) != 0)
+   {
+# ifdef PNG_READ_eXIf_SUPPORTED
+      if (info_ptr->eXIf_buf)
+      {
+         png_free(png_ptr, info_ptr->eXIf_buf);
+         info_ptr->eXIf_buf = NULL;
+      }
+# endif
+      if (info_ptr->exif)
+      {
+         png_free(png_ptr, info_ptr->exif);
+         info_ptr->exif = NULL;
+      }
+      info_ptr->valid &= ~PNG_INFO_eXIf;
+   }
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+   /* Free any hIST entry */
+   if (((mask & PNG_FREE_HIST) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->hist);
+      info_ptr->hist = NULL;
+      info_ptr->valid &= ~PNG_INFO_hIST;
+   }
+#endif
+
+   /* Free any PLTE entry that was internally allocated */
+   if (((mask & PNG_FREE_PLTE) & info_ptr->free_me) != 0)
+   {
+      png_free(png_ptr, info_ptr->palette);
+      info_ptr->palette = NULL;
+      info_ptr->valid &= ~PNG_INFO_PLTE;
+      info_ptr->num_palette = 0;
+   }
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+   /* Free any image bits attached to the info structure */
+   if (((mask & PNG_FREE_ROWS) & info_ptr->free_me) != 0)
+   {
+      if (info_ptr->row_pointers != NULL)
+      {
+         png_uint_32 row;
+         for (row = 0; row < info_ptr->height; row++)
+            png_free(png_ptr, info_ptr->row_pointers[row]);
+
+         png_free(png_ptr, info_ptr->row_pointers);
+         info_ptr->row_pointers = NULL;
+      }
+      info_ptr->valid &= ~PNG_INFO_IDAT;
+   }
+#endif
+
+   if (num != -1)
+      mask &= ~PNG_FREE_MUL;
+
+   info_ptr->free_me &= ~mask;
+}
+#endif /* READ || WRITE */
+
+/* This function returns a pointer to the io_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy() or png_read_destroy() are called.
+ */
+png_voidp PNGAPI
+png_get_io_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return NULL;
+
+   return png_ptr->io_ptr;
+}
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+#  ifdef PNG_STDIO_SUPPORTED
+/* Initialize the default input/output functions for the PNG file.  If you
+ * use your own read or write routines, you can call either png_set_read_fn()
+ * or png_set_write_fn() instead of png_init_io().  If you have defined
+ * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
+ * function of your own because "FILE *" isn't necessarily available.
+ */
+void PNGAPI
+png_init_io(png_structrp png_ptr, png_FILE_p fp)
+{
+   png_debug(1, "in png_init_io");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->io_ptr = (png_voidp)fp;
+}
+#  endif
+
+#  ifdef PNG_SAVE_INT_32_SUPPORTED
+/* PNG signed integers are saved in 32-bit 2's complement format.  ANSI C-90
+ * defines a cast of a signed integer to an unsigned integer either to preserve
+ * the value, if it is positive, or to calculate:
+ *
+ *     (UNSIGNED_MAX+1) + integer
+ *
+ * Where UNSIGNED_MAX is the appropriate maximum unsigned value, so when the
+ * negative integral value is added the result will be an unsigned value
+ * corresponding to the 2's complement representation.
+ */
+void PNGAPI
+png_save_int_32(png_bytep buf, png_int_32 i)
+{
+   png_save_uint_32(buf, (png_uint_32)i);
+}
+#  endif
+
+#  ifdef PNG_TIME_RFC1123_SUPPORTED
+/* Convert the supplied time into an RFC 1123 string suitable for use in
+ * a "Creation Time" or other text-based time string.
+ */
+int PNGAPI
+png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime)
+{
+   static const char short_months[12][4] =
+        {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
+
+   if (out == NULL)
+      return 0;
+
+   if (ptime->year > 9999 /* RFC1123 limitation */ ||
+       ptime->month == 0    ||  ptime->month > 12  ||
+       ptime->day   == 0    ||  ptime->day   > 31  ||
+       ptime->hour  > 23    ||  ptime->minute > 59 ||
+       ptime->second > 60)
+      return 0;
+
+   {
+      size_t pos = 0;
+      char number_buf[5] = {0, 0, 0, 0, 0}; /* enough for a four-digit year */
+
+#     define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string))
+#     define APPEND_NUMBER(format, value)\
+         APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
+#     define APPEND(ch) if (pos < 28) out[pos++] = (ch)
+
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
+      APPEND(' ');
+      APPEND_STRING(short_months[(ptime->month - 1)]);
+      APPEND(' ');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
+      APPEND(' ');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
+      APPEND(':');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
+      APPEND(':');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
+      APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
+      PNG_UNUSED (pos)
+
+#     undef APPEND
+#     undef APPEND_NUMBER
+#     undef APPEND_STRING
+   }
+
+   return 1;
+}
+
+#    if PNG_LIBPNG_VER < 10700
+/* To do: remove the following from libpng-1.7 */
+/* Original API that uses a private buffer in png_struct.
+ * Deprecated because it causes png_struct to carry a spurious temporary
+ * buffer (png_struct::time_buffer), better to have the caller pass this in.
+ */
+png_const_charp PNGAPI
+png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime)
+{
+   if (png_ptr != NULL)
+   {
+      /* The only failure above if png_ptr != NULL is from an invalid ptime */
+      if (png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime) == 0)
+         png_warning(png_ptr, "Ignoring invalid time value");
+
+      else
+         return png_ptr->time_buffer;
+   }
+
+   return NULL;
+}
+#    endif /* LIBPNG_VER < 10700 */
+#  endif /* TIME_RFC1123 */
+
+#endif /* READ || WRITE */
+
+png_const_charp PNGAPI
+png_get_copyright(png_const_structrp png_ptr)
+{
+   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
+#ifdef PNG_STRING_COPYRIGHT
+   return PNG_STRING_COPYRIGHT
+#else
+   return PNG_STRING_NEWLINE \
+      "libpng version 1.6.43" PNG_STRING_NEWLINE \
+      "Copyright (c) 2018-2024 Cosmin Truta" PNG_STRING_NEWLINE \
+      "Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson" \
+      PNG_STRING_NEWLINE \
+      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
+      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
+      PNG_STRING_NEWLINE;
+#endif
+}
+
+/* The following return the library version as a short string in the
+ * format 1.0.0 through 99.99.99zz.  To get the version of *.h files
+ * used with your application, print out PNG_LIBPNG_VER_STRING, which
+ * is defined in png.h.
+ * Note: now there is no difference between png_get_libpng_ver() and
+ * png_get_header_ver().  Due to the version_nn_nn_nn typedef guard,
+ * it is guaranteed that png.c uses the correct version of png.h.
+ */
+png_const_charp PNGAPI
+png_get_libpng_ver(png_const_structrp png_ptr)
+{
+   /* Version of *.c files used when building libpng */
+   return png_get_header_ver(png_ptr);
+}
+
+png_const_charp PNGAPI
+png_get_header_ver(png_const_structrp png_ptr)
+{
+   /* Version of *.h files used when building libpng */
+   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
+   return PNG_LIBPNG_VER_STRING;
+}
+
+png_const_charp PNGAPI
+png_get_header_version(png_const_structrp png_ptr)
+{
+   /* Returns longer string containing both version and date */
+   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
+#ifdef __STDC__
+   return PNG_HEADER_VERSION_STRING
+#  ifndef PNG_READ_SUPPORTED
+      " (NO READ SUPPORT)"
+#  endif
+      PNG_STRING_NEWLINE;
+#else
+   return PNG_HEADER_VERSION_STRING;
+#endif
+}
+
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+/* NOTE: this routine is not used internally! */
+/* Build a grayscale palette.  Palette is assumed to be 1 << bit_depth
+ * large of png_color.  This lets grayscale images be treated as
+ * paletted.  Most useful for gamma correction and simplification
+ * of code.  This API is not used internally.
+ */
+void PNGAPI
+png_build_grayscale_palette(int bit_depth, png_colorp palette)
+{
+   int num_palette;
+   int color_inc;
+   int i;
+   int v;
+
+   png_debug(1, "in png_do_build_grayscale_palette");
+
+   if (palette == NULL)
+      return;
+
+   switch (bit_depth)
+   {
+      case 1:
+         num_palette = 2;
+         color_inc = 0xff;
+         break;
+
+      case 2:
+         num_palette = 4;
+         color_inc = 0x55;
+         break;
+
+      case 4:
+         num_palette = 16;
+         color_inc = 0x11;
+         break;
+
+      case 8:
+         num_palette = 256;
+         color_inc = 1;
+         break;
+
+      default:
+         num_palette = 0;
+         color_inc = 0;
+         break;
+   }
+
+   for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
+   {
+      palette[i].red = (png_byte)(v & 0xff);
+      palette[i].green = (png_byte)(v & 0xff);
+      palette[i].blue = (png_byte)(v & 0xff);
+   }
+}
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+int PNGAPI
+png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)
+{
+   /* Check chunk_name and return "keep" value if it's on the list, else 0 */
+   png_const_bytep p, p_end;
+
+   if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0)
+      return PNG_HANDLE_CHUNK_AS_DEFAULT;
+
+   p_end = png_ptr->chunk_list;
+   p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
+
+   /* The code is the fifth byte after each four byte string.  Historically this
+    * code was always searched from the end of the list, this is no longer
+    * necessary because the 'set' routine handles duplicate entries correctly.
+    */
+   do /* num_chunk_list > 0, so at least one */
+   {
+      p -= 5;
+
+      if (memcmp(chunk_name, p, 4) == 0)
+         return p[4];
+   }
+   while (p > p_end);
+
+   /* This means that known chunks should be processed and unknown chunks should
+    * be handled according to the value of png_ptr->unknown_default; this can be
+    * confusing because, as a result, there are two levels of defaulting for
+    * unknown chunks.
+    */
+   return PNG_HANDLE_CHUNK_AS_DEFAULT;
+}
+
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
+   defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+int /* PRIVATE */
+png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name)
+{
+   png_byte chunk_string[5];
+
+   PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
+   return png_handle_as_unknown(png_ptr, chunk_string);
+}
+#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
+#endif /* SET_UNKNOWN_CHUNKS */
+
+#ifdef PNG_READ_SUPPORTED
+/* This function, added to libpng-1.0.6g, is untested. */
+int PNGAPI
+png_reset_zstream(png_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return Z_STREAM_ERROR;
+
+   /* WARNING: this resets the window bits to the maximum! */
+   return inflateReset(&png_ptr->zstream);
+}
+#endif /* READ */
+
+/* This function was added to libpng-1.0.7 */
+png_uint_32 PNGAPI
+png_access_version_number(void)
+{
+   /* Version of *.c files used when building libpng */
+   return (png_uint_32)PNG_LIBPNG_VER;
+}
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Ensure that png_ptr->zstream.msg holds some appropriate error message string.
+ * If it doesn't 'ret' is used to set it to something appropriate, even in cases
+ * like Z_OK or Z_STREAM_END where the error code is apparently a success code.
+ */
+void /* PRIVATE */
+png_zstream_error(png_structrp png_ptr, int ret)
+{
+   /* Translate 'ret' into an appropriate error string, priority is given to the
+    * one in zstream if set.  This always returns a string, even in cases like
+    * Z_OK or Z_STREAM_END where the error code is a success code.
+    */
+   if (png_ptr->zstream.msg == NULL) switch (ret)
+   {
+      default:
+      case Z_OK:
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code");
+         break;
+
+      case Z_STREAM_END:
+         /* Normal exit */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream");
+         break;
+
+      case Z_NEED_DICT:
+         /* This means the deflate stream did not have a dictionary; this
+          * indicates a bogus PNG.
+          */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary");
+         break;
+
+      case Z_ERRNO:
+         /* gz APIs only: should not happen */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error");
+         break;
+
+      case Z_STREAM_ERROR:
+         /* internal libpng error */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib");
+         break;
+
+      case Z_DATA_ERROR:
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream");
+         break;
+
+      case Z_MEM_ERROR:
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory");
+         break;
+
+      case Z_BUF_ERROR:
+         /* End of input or output; not a problem if the caller is doing
+          * incremental read or write.
+          */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated");
+         break;
+
+      case Z_VERSION_ERROR:
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version");
+         break;
+
+      case PNG_UNEXPECTED_ZLIB_RETURN:
+         /* Compile errors here mean that zlib now uses the value co-opted in
+          * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above
+          * and change pngpriv.h.  Note that this message is "... return",
+          * whereas the default/Z_OK one is "... return code".
+          */
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return");
+         break;
+   }
+}
+
+/* png_convert_size: a PNGAPI but no longer in png.h, so deleted
+ * at libpng 1.5.5!
+ */
+
+/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
+#ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */
+static int
+png_colorspace_check_gamma(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, png_fixed_point gAMA, int from)
+   /* This is called to check a new gamma value against an existing one.  The
+    * routine returns false if the new gamma value should not be written.
+    *
+    * 'from' says where the new gamma value comes from:
+    *
+    *    0: the new gamma value is the libpng estimate for an ICC profile
+    *    1: the new gamma value comes from a gAMA chunk
+    *    2: the new gamma value comes from an sRGB chunk
+    */
+{
+   png_fixed_point gtest;
+
+   if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+       (png_muldiv(&gtest, colorspace->gamma, PNG_FP_1, gAMA) == 0  ||
+      png_gamma_significant(gtest) != 0))
+   {
+      /* Either this is an sRGB image, in which case the calculated gamma
+       * approximation should match, or this is an image with a profile and the
+       * value libpng calculates for the gamma of the profile does not match the
+       * value recorded in the file.  The former, sRGB, case is an error, the
+       * latter is just a warning.
+       */
+      if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2)
+      {
+         png_chunk_report(png_ptr, "gamma value does not match sRGB",
+             PNG_CHUNK_ERROR);
+         /* Do not overwrite an sRGB value */
+         return from == 2;
+      }
+
+      else /* sRGB tag not involved */
+      {
+         png_chunk_report(png_ptr, "gamma value does not match libpng estimate",
+             PNG_CHUNK_WARNING);
+         return from == 1;
+      }
+   }
+
+   return 1;
+}
+
+void /* PRIVATE */
+png_colorspace_set_gamma(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, png_fixed_point gAMA)
+{
+   /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
+    * occur.  Since the fixed point representation is asymmetrical it is
+    * possible for 1/gamma to overflow the limit of 21474 and this means the
+    * gamma value must be at least 5/100000 and hence at most 20000.0.  For
+    * safety the limits here are a little narrower.  The values are 0.00016 to
+    * 6250.0, which are truly ridiculous gamma values (and will produce
+    * displays that are all black or all white.)
+    *
+    * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk
+    * handling code, which only required the value to be >0.
+    */
+   png_const_charp errmsg;
+
+   if (gAMA < 16 || gAMA > 625000000)
+      errmsg = "gamma value out of range";
+
+#  ifdef PNG_READ_gAMA_SUPPORTED
+   /* Allow the application to set the gamma value more than once */
+   else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+      (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0)
+      errmsg = "duplicate";
+#  endif
+
+   /* Do nothing if the colorspace is already invalid */
+   else if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+      return;
+
+   else
+   {
+      if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA,
+          1/*from gAMA*/) != 0)
+      {
+         /* Store this gamma value. */
+         colorspace->gamma = gAMA;
+         colorspace->flags |=
+            (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA);
+      }
+
+      /* At present if the check_gamma test fails the gamma of the colorspace is
+       * not updated however the colorspace is not invalidated.  This
+       * corresponds to the case where the existing gamma comes from an sRGB
+       * chunk or profile.  An error message has already been output.
+       */
+      return;
+   }
+
+   /* Error exit - errmsg has been set. */
+   colorspace->flags |= PNG_COLORSPACE_INVALID;
+   png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR);
+}
+
+void /* PRIVATE */
+png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr)
+{
+   if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+   {
+      /* Everything is invalid */
+      info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB|
+         PNG_INFO_iCCP);
+
+#     ifdef PNG_COLORSPACE_SUPPORTED
+      /* Clean up the iCCP profile now if it won't be used. */
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/);
+#     else
+      PNG_UNUSED(png_ptr)
+#     endif
+   }
+
+   else
+   {
+#     ifdef PNG_COLORSPACE_SUPPORTED
+      /* Leave the INFO_iCCP flag set if the pngset.c code has already set
+       * it; this allows a PNG to contain a profile which matches sRGB and
+       * yet still have that profile retrievable by the application.
+       */
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) != 0)
+         info_ptr->valid |= PNG_INFO_sRGB;
+
+      else
+         info_ptr->valid &= ~PNG_INFO_sRGB;
+
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+         info_ptr->valid |= PNG_INFO_cHRM;
+
+      else
+         info_ptr->valid &= ~PNG_INFO_cHRM;
+#     endif
+
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0)
+         info_ptr->valid |= PNG_INFO_gAMA;
+
+      else
+         info_ptr->valid &= ~PNG_INFO_gAMA;
+   }
+}
+
+#ifdef PNG_READ_SUPPORTED
+void /* PRIVATE */
+png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr)
+{
+   if (info_ptr == NULL) /* reduce code size; check here not in the caller */
+      return;
+
+   info_ptr->colorspace = png_ptr->colorspace;
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+#endif
+#endif /* GAMMA */
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+/* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
+ * cHRM, as opposed to using chromaticities.  These internal APIs return
+ * non-zero on a parameter error.  The X, Y and Z values are required to be
+ * positive and less than 1.0.
+ */
+static int
+png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ)
+{
+   png_int_32 d, dwhite, whiteX, whiteY;
+
+   d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z;
+   if (png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d) == 0)
+      return 1;
+   if (png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d) == 0)
+      return 1;
+   dwhite = d;
+   whiteX = XYZ->red_X;
+   whiteY = XYZ->red_Y;
+
+   d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z;
+   if (png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d) == 0)
+      return 1;
+   if (png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d) == 0)
+      return 1;
+   dwhite += d;
+   whiteX += XYZ->green_X;
+   whiteY += XYZ->green_Y;
+
+   d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z;
+   if (png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d) == 0)
+      return 1;
+   if (png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d) == 0)
+      return 1;
+   dwhite += d;
+   whiteX += XYZ->blue_X;
+   whiteY += XYZ->blue_Y;
+
+   /* The reference white is simply the sum of the end-point (X,Y,Z) vectors,
+    * thus:
+    */
+   if (png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite) == 0)
+      return 1;
+   if (png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite) == 0)
+      return 1;
+
+   return 0;
+}
+
+static int
+png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
+{
+   png_fixed_point red_inverse, green_inverse, blue_scale;
+   png_fixed_point left, right, denominator;
+
+   /* Check xy and, implicitly, z.  Note that wide gamut color spaces typically
+    * have end points with 0 tristimulus values (these are impossible end
+    * points, but they are used to cover the possible colors).  We check
+    * xy->whitey against 5, not 0, to avoid a possible integer overflow.
+    */
+   if (xy->redx   < 0 || xy->redx > PNG_FP_1) return 1;
+   if (xy->redy   < 0 || xy->redy > PNG_FP_1-xy->redx) return 1;
+   if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1;
+   if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1;
+   if (xy->bluex  < 0 || xy->bluex > PNG_FP_1) return 1;
+   if (xy->bluey  < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1;
+   if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1;
+   if (xy->whitey < 5 || xy->whitey > PNG_FP_1-xy->whitex) return 1;
+
+   /* The reverse calculation is more difficult because the original tristimulus
+    * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
+    * derived values were recorded in the cHRM chunk;
+    * (red,green,blue,white)x(x,y).  This loses one degree of freedom and
+    * therefore an arbitrary ninth value has to be introduced to undo the
+    * original transformations.
+    *
+    * Think of the original end-points as points in (X,Y,Z) space.  The
+    * chromaticity values (c) have the property:
+    *
+    *           C
+    *   c = ---------
+    *       X + Y + Z
+    *
+    * For each c (x,y,z) from the corresponding original C (X,Y,Z).  Thus the
+    * three chromaticity values (x,y,z) for each end-point obey the
+    * relationship:
+    *
+    *   x + y + z = 1
+    *
+    * This describes the plane in (X,Y,Z) space that intersects each axis at the
+    * value 1.0; call this the chromaticity plane.  Thus the chromaticity
+    * calculation has scaled each end-point so that it is on the x+y+z=1 plane
+    * and chromaticity is the intersection of the vector from the origin to the
+    * (X,Y,Z) value with the chromaticity plane.
+    *
+    * To fully invert the chromaticity calculation we would need the three
+    * end-point scale factors, (red-scale, green-scale, blue-scale), but these
+    * were not recorded.  Instead we calculated the reference white (X,Y,Z) and
+    * recorded the chromaticity of this.  The reference white (X,Y,Z) would have
+    * given all three of the scale factors since:
+    *
+    *    color-C = color-c * color-scale
+    *    white-C = red-C + green-C + blue-C
+    *            = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+    *
+    * But cHRM records only white-x and white-y, so we have lost the white scale
+    * factor:
+    *
+    *    white-C = white-c*white-scale
+    *
+    * To handle this the inverse transformation makes an arbitrary assumption
+    * about white-scale:
+    *
+    *    Assume: white-Y = 1.0
+    *    Hence:  white-scale = 1/white-y
+    *    Or:     red-Y + green-Y + blue-Y = 1.0
+    *
+    * Notice the last statement of the assumption gives an equation in three of
+    * the nine values we want to calculate.  8 more equations come from the
+    * above routine as summarised at the top above (the chromaticity
+    * calculation):
+    *
+    *    Given: color-x = color-X / (color-X + color-Y + color-Z)
+    *    Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0
+    *
+    * This is 9 simultaneous equations in the 9 variables "color-C" and can be
+    * solved by Cramer's rule.  Cramer's rule requires calculating 10 9x9 matrix
+    * determinants, however this is not as bad as it seems because only 28 of
+    * the total of 90 terms in the various matrices are non-zero.  Nevertheless
+    * Cramer's rule is notoriously numerically unstable because the determinant
+    * calculation involves the difference of large, but similar, numbers.  It is
+    * difficult to be sure that the calculation is stable for real world values
+    * and it is certain that it becomes unstable where the end points are close
+    * together.
+    *
+    * So this code uses the perhaps slightly less optimal but more
+    * understandable and totally obvious approach of calculating color-scale.
+    *
+    * This algorithm depends on the precision in white-scale and that is
+    * (1/white-y), so we can immediately see that as white-y approaches 0 the
+    * accuracy inherent in the cHRM chunk drops off substantially.
+    *
+    * libpng arithmetic: a simple inversion of the above equations
+    * ------------------------------------------------------------
+    *
+    *    white_scale = 1/white-y
+    *    white-X = white-x * white-scale
+    *    white-Y = 1.0
+    *    white-Z = (1 - white-x - white-y) * white_scale
+    *
+    *    white-C = red-C + green-C + blue-C
+    *            = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+    *
+    * This gives us three equations in (red-scale,green-scale,blue-scale) where
+    * all the coefficients are now known:
+    *
+    *    red-x*red-scale + green-x*green-scale + blue-x*blue-scale
+    *       = white-x/white-y
+    *    red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1
+    *    red-z*red-scale + green-z*green-scale + blue-z*blue-scale
+    *       = (1 - white-x - white-y)/white-y
+    *
+    * In the last equation color-z is (1 - color-x - color-y) so we can add all
+    * three equations together to get an alternative third:
+    *
+    *    red-scale + green-scale + blue-scale = 1/white-y = white-scale
+    *
+    * So now we have a Cramer's rule solution where the determinants are just
+    * 3x3 - far more tractible.  Unfortunately 3x3 determinants still involve
+    * multiplication of three coefficients so we can't guarantee to avoid
+    * overflow in the libpng fixed point representation.  Using Cramer's rule in
+    * floating point is probably a good choice here, but it's not an option for
+    * fixed point.  Instead proceed to simplify the first two equations by
+    * eliminating what is likely to be the largest value, blue-scale:
+    *
+    *    blue-scale = white-scale - red-scale - green-scale
+    *
+    * Hence:
+    *
+    *    (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale =
+    *                (white-x - blue-x)*white-scale
+    *
+    *    (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale =
+    *                1 - blue-y*white-scale
+    *
+    * And now we can trivially solve for (red-scale,green-scale):
+    *
+    *    green-scale =
+    *                (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale
+    *                -----------------------------------------------------------
+    *                                  green-x - blue-x
+    *
+    *    red-scale =
+    *                1 - blue-y*white-scale - (green-y - blue-y) * green-scale
+    *                ---------------------------------------------------------
+    *                                  red-y - blue-y
+    *
+    * Hence:
+    *
+    *    red-scale =
+    *          ( (green-x - blue-x) * (white-y - blue-y) -
+    *            (green-y - blue-y) * (white-x - blue-x) ) / white-y
+    * -------------------------------------------------------------------------
+    *  (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+    *
+    *    green-scale =
+    *          ( (red-y - blue-y) * (white-x - blue-x) -
+    *            (red-x - blue-x) * (white-y - blue-y) ) / white-y
+    * -------------------------------------------------------------------------
+    *  (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+    *
+    * Accuracy:
+    * The input values have 5 decimal digits of accuracy.  The values are all in
+    * the range 0 < value < 1, so simple products are in the same range but may
+    * need up to 10 decimal digits to preserve the original precision and avoid
+    * underflow.  Because we are using a 32-bit signed representation we cannot
+    * match this; the best is a little over 9 decimal digits, less than 10.
+    *
+    * The approach used here is to preserve the maximum precision within the
+    * signed representation.  Because the red-scale calculation above uses the
+    * difference between two products of values that must be in the range -1..+1
+    * it is sufficient to divide the product by 7; ceil(100,000/32767*2).  The
+    * factor is irrelevant in the calculation because it is applied to both
+    * numerator and denominator.
+    *
+    * Note that the values of the differences of the products of the
+    * chromaticities in the above equations tend to be small, for example for
+    * the sRGB chromaticities they are:
+    *
+    * red numerator:    -0.04751
+    * green numerator:  -0.08788
+    * denominator:      -0.2241 (without white-y multiplication)
+    *
+    *  The resultant Y coefficients from the chromaticities of some widely used
+    *  color space definitions are (to 15 decimal places):
+    *
+    *  sRGB
+    *    0.212639005871510 0.715168678767756 0.072192315360734
+    *  Kodak ProPhoto
+    *    0.288071128229293 0.711843217810102 0.000085653960605
+    *  Adobe RGB
+    *    0.297344975250536 0.627363566255466 0.075291458493998
+    *  Adobe Wide Gamut RGB
+    *    0.258728243040113 0.724682314948566 0.016589442011321
+    */
+   /* By the argument, above overflow should be impossible here. The return
+    * value of 2 indicates an internal error to the caller.
+    */
+   if (png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7) == 0)
+      return 2;
+   if (png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7) == 0)
+      return 2;
+   denominator = left - right;
+
+   /* Now find the red numerator. */
+   if (png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
+      return 2;
+   if (png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
+      return 2;
+
+   /* Overflow is possible here and it indicates an extreme set of PNG cHRM
+    * chunk values.  This calculation actually returns the reciprocal of the
+    * scale value because this allows us to delay the multiplication of white-y
+    * into the denominator, which tends to produce a small number.
+    */
+   if (png_muldiv(&red_inverse, xy->whitey, denominator, left-right) == 0 ||
+       red_inverse <= xy->whitey /* r+g+b scales = white scale */)
+      return 1;
+
+   /* Similarly for green_inverse: */
+   if (png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
+      return 2;
+   if (png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
+      return 2;
+   if (png_muldiv(&green_inverse, xy->whitey, denominator, left-right) == 0 ||
+       green_inverse <= xy->whitey)
+      return 1;
+
+   /* And the blue scale, the checks above guarantee this can't overflow but it
+    * can still produce 0 for extreme cHRM values.
+    */
+   blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) -
+       png_reciprocal(green_inverse);
+   if (blue_scale <= 0)
+      return 1;
+
+
+   /* And fill in the png_XYZ: */
+   if (png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1,
+       red_inverse) == 0)
+      return 1;
+
+   if (png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1,
+       green_inverse) == 0)
+      return 1;
+
+   if (png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1) == 0)
+      return 1;
+   if (png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale,
+       PNG_FP_1) == 0)
+      return 1;
+
+   return 0; /*success*/
+}
+
+static int
+png_XYZ_normalize(png_XYZ *XYZ)
+{
+   png_int_32 Y;
+
+   if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 ||
+      XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 ||
+      XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0)
+      return 1;
+
+   /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1.
+    * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore
+    * relying on addition of two positive values producing a negative one is not
+    * safe.
+    */
+   Y = XYZ->red_Y;
+   if (0x7fffffff - Y < XYZ->green_X)
+      return 1;
+   Y += XYZ->green_Y;
+   if (0x7fffffff - Y < XYZ->blue_X)
+      return 1;
+   Y += XYZ->blue_Y;
+
+   if (Y != PNG_FP_1)
+   {
+      if (png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y) == 0)
+         return 1;
+
+      if (png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y) == 0)
+         return 1;
+
+      if (png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y) == 0)
+         return 1;
+      if (png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y) == 0)
+         return 1;
+   }
+
+   return 0;
+}
+
+static int
+png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta)
+{
+   /* Allow an error of +/-0.01 (absolute value) on each chromaticity */
+   if (PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) ||
+       PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) ||
+       PNG_OUT_OF_RANGE(xy1->redx,   xy2->redx,  delta) ||
+       PNG_OUT_OF_RANGE(xy1->redy,   xy2->redy,  delta) ||
+       PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) ||
+       PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) ||
+       PNG_OUT_OF_RANGE(xy1->bluex,  xy2->bluex, delta) ||
+       PNG_OUT_OF_RANGE(xy1->bluey,  xy2->bluey, delta))
+      return 0;
+   return 1;
+}
+
+/* Added in libpng-1.6.0, a different check for the validity of a set of cHRM
+ * chunk chromaticities.  Earlier checks used to simply look for the overflow
+ * condition (where the determinant of the matrix to solve for XYZ ends up zero
+ * because the chromaticity values are not all distinct.)  Despite this it is
+ * theoretically possible to produce chromaticities that are apparently valid
+ * but that rapidly degrade to invalid, potentially crashing, sets because of
+ * arithmetic inaccuracies when calculations are performed on them.  The new
+ * check is to round-trip xy -> XYZ -> xy and then check that the result is
+ * within a small percentage of the original.
+ */
+static int
+png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy)
+{
+   int result;
+   png_xy xy_test;
+
+   /* As a side-effect this routine also returns the XYZ endpoints. */
+   result = png_XYZ_from_xy(XYZ, xy);
+   if (result != 0)
+      return result;
+
+   result = png_xy_from_XYZ(&xy_test, XYZ);
+   if (result != 0)
+      return result;
+
+   if (png_colorspace_endpoints_match(xy, &xy_test,
+       5/*actually, the math is pretty accurate*/) != 0)
+      return 0;
+
+   /* Too much slip */
+   return 1;
+}
+
+/* This is the check going the other way.  The XYZ is modified to normalize it
+ * (another side-effect) and the xy chromaticities are returned.
+ */
+static int
+png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ)
+{
+   int result;
+   png_XYZ XYZtemp;
+
+   result = png_XYZ_normalize(XYZ);
+   if (result != 0)
+      return result;
+
+   result = png_xy_from_XYZ(xy, XYZ);
+   if (result != 0)
+      return result;
+
+   XYZtemp = *XYZ;
+   return png_colorspace_check_xy(&XYZtemp, xy);
+}
+
+/* Used to check for an endpoint match against sRGB */
+static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */
+{
+   /* color      x       y */
+   /* red   */ 64000, 33000,
+   /* green */ 30000, 60000,
+   /* blue  */ 15000,  6000,
+   /* white */ 31270, 32900
+};
+
+static int
+png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ,
+    int preferred)
+{
+   if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+      return 0;
+
+   /* The consistency check is performed on the chromaticities; this factors out
+    * variations because of the normalization (or not) of the end point Y
+    * values.
+    */
+   if (preferred < 2 &&
+       (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      /* The end points must be reasonably close to any we already have.  The
+       * following allows an error of up to +/-.001
+       */
+      if (png_colorspace_endpoints_match(xy, &colorspace->end_points_xy,
+          100) == 0)
+      {
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_benign_error(png_ptr, "inconsistent chromaticities");
+         return 0; /* failed */
+      }
+
+      /* Only overwrite with preferred values */
+      if (preferred == 0)
+         return 1; /* ok, but no change */
+   }
+
+   colorspace->end_points_xy = *xy;
+   colorspace->end_points_XYZ = *XYZ;
+   colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS;
+
+   /* The end points are normally quoted to two decimal digits, so allow +/-0.01
+    * on this test.
+    */
+   if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000) != 0)
+      colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB;
+
+   else
+      colorspace->flags &= PNG_COLORSPACE_CANCEL(
+         PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
+
+   return 2; /* ok and changed */
+}
+
+int /* PRIVATE */
+png_colorspace_set_chromaticities(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, const png_xy *xy, int preferred)
+{
+   /* We must check the end points to ensure they are reasonable - in the past
+    * color management systems have crashed as a result of getting bogus
+    * colorant values, while this isn't the fault of libpng it is the
+    * responsibility of libpng because PNG carries the bomb and libpng is in a
+    * position to protect against it.
+    */
+   png_XYZ XYZ;
+
+   switch (png_colorspace_check_xy(&XYZ, xy))
+   {
+      case 0: /* success */
+         return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ,
+             preferred);
+
+      case 1:
+         /* We can't invert the chromaticities so we can't produce value XYZ
+          * values.  Likely as not a color management system will fail too.
+          */
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_benign_error(png_ptr, "invalid chromaticities");
+         break;
+
+      default:
+         /* libpng is broken; this should be a warning but if it happens we
+          * want error reports so for the moment it is an error.
+          */
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_error(png_ptr, "internal error checking chromaticities");
+   }
+
+   return 0; /* failed */
+}
+
+int /* PRIVATE */
+png_colorspace_set_endpoints(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred)
+{
+   png_XYZ XYZ = *XYZ_in;
+   png_xy xy;
+
+   switch (png_colorspace_check_XYZ(&xy, &XYZ))
+   {
+      case 0:
+         return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ,
+             preferred);
+
+      case 1:
+         /* End points are invalid. */
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_benign_error(png_ptr, "invalid end points");
+         break;
+
+      default:
+         colorspace->flags |= PNG_COLORSPACE_INVALID;
+         png_error(png_ptr, "internal error checking chromaticities");
+   }
+
+   return 0; /* failed */
+}
+
+#if defined(PNG_sRGB_SUPPORTED) || defined(PNG_iCCP_SUPPORTED)
+/* Error message generation */
+static char
+png_icc_tag_char(png_uint_32 byte)
+{
+   byte &= 0xff;
+   if (byte >= 32 && byte <= 126)
+      return (char)byte;
+   else
+      return '?';
+}
+
+static void
+png_icc_tag_name(char *name, png_uint_32 tag)
+{
+   name[0] = '\'';
+   name[1] = png_icc_tag_char(tag >> 24);
+   name[2] = png_icc_tag_char(tag >> 16);
+   name[3] = png_icc_tag_char(tag >>  8);
+   name[4] = png_icc_tag_char(tag      );
+   name[5] = '\'';
+}
+
+static int
+is_ICC_signature_char(png_alloc_size_t it)
+{
+   return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) ||
+      (it >= 97 && it <= 122);
+}
+
+static int
+is_ICC_signature(png_alloc_size_t it)
+{
+   return is_ICC_signature_char(it >> 24) /* checks all the top bits */ &&
+      is_ICC_signature_char((it >> 16) & 0xff) &&
+      is_ICC_signature_char((it >> 8) & 0xff) &&
+      is_ICC_signature_char(it & 0xff);
+}
+
+static int
+png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_alloc_size_t value, png_const_charp reason)
+{
+   size_t pos;
+   char message[196]; /* see below for calculation */
+
+   if (colorspace != NULL)
+      colorspace->flags |= PNG_COLORSPACE_INVALID;
+
+   pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */
+   pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */
+   pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */
+   if (is_ICC_signature(value) != 0)
+   {
+      /* So 'value' is at most 4 bytes and the following cast is safe */
+      png_icc_tag_name(message+pos, (png_uint_32)value);
+      pos += 6; /* total +8; less than the else clause */
+      message[pos++] = ':';
+      message[pos++] = ' ';
+   }
+#  ifdef PNG_WARNINGS_SUPPORTED
+   else
+   {
+      char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114 */
+
+      pos = png_safecat(message, (sizeof message), pos,
+          png_format_number(number, number+(sizeof number),
+          PNG_NUMBER_FORMAT_x, value));
+      pos = png_safecat(message, (sizeof message), pos, "h: "); /* +2 = 116 */
+   }
+#  endif
+   /* The 'reason' is an arbitrary message, allow +79 maximum 195 */
+   pos = png_safecat(message, (sizeof message), pos, reason);
+   PNG_UNUSED(pos)
+
+   /* This is recoverable, but make it unconditionally an app_error on write to
+    * avoid writing invalid ICC profiles into PNG files (i.e., we handle them
+    * on read, with a warning, but on write unless the app turns off
+    * application errors the PNG won't be written.)
+    */
+   png_chunk_report(png_ptr, message,
+       (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR);
+
+   return 0;
+}
+#endif /* sRGB || iCCP */
+
+#ifdef PNG_sRGB_SUPPORTED
+int /* PRIVATE */
+png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    int intent)
+{
+   /* sRGB sets known gamma, end points and (from the chunk) intent. */
+   /* IMPORTANT: these are not necessarily the values found in an ICC profile
+    * because ICC profiles store values adapted to a D50 environment; it is
+    * expected that the ICC profile mediaWhitePointTag will be D50; see the
+    * checks and code elsewhere to understand this better.
+    *
+    * These XYZ values, which are accurate to 5dp, produce rgb to gray
+    * coefficients of (6968,23435,2366), which are reduced (because they add up
+    * to 32769 not 32768) to (6968,23434,2366).  These are the values that
+    * libpng has traditionally used (and are the best values given the 15bit
+    * algorithm used by the rgb to gray code.)
+    */
+   static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */
+   {
+      /* color      X      Y      Z */
+      /* red   */ 41239, 21264,  1933,
+      /* green */ 35758, 71517, 11919,
+      /* blue  */ 18048,  7219, 95053
+   };
+
+   /* Do nothing if the colorspace is already invalidated. */
+   if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+      return 0;
+
+   /* Check the intent, then check for existing settings.  It is valid for the
+    * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must
+    * be consistent with the correct values.  If, however, this function is
+    * called below because an iCCP chunk matches sRGB then it is quite
+    * conceivable that an older app recorded incorrect gAMA and cHRM because of
+    * an incorrect calculation based on the values in the profile - this does
+    * *not* invalidate the profile (though it still produces an error, which can
+    * be ignored.)
+    */
+   if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST)
+      return png_icc_profile_error(png_ptr, colorspace, "sRGB",
+          (png_alloc_size_t)intent, "invalid sRGB rendering intent");
+
+   if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 &&
+       colorspace->rendering_intent != intent)
+      return png_icc_profile_error(png_ptr, colorspace, "sRGB",
+         (png_alloc_size_t)intent, "inconsistent rendering intents");
+
+   if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0)
+   {
+      png_benign_error(png_ptr, "duplicate sRGB information ignored");
+      return 0;
+   }
+
+   /* If the standard sRGB cHRM chunk does not match the one from the PNG file
+    * warn but overwrite the value with the correct one.
+    */
+   if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 &&
+       !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy,
+       100))
+      png_chunk_report(png_ptr, "cHRM chunk does not match sRGB",
+         PNG_CHUNK_ERROR);
+
+   /* This check is just done for the error reporting - the routine always
+    * returns true when the 'from' argument corresponds to sRGB (2).
+    */
+   (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE,
+       2/*from sRGB*/);
+
+   /* intent: bugs in GCC force 'int' to be used as the parameter type. */
+   colorspace->rendering_intent = (png_uint_16)intent;
+   colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT;
+
+   /* endpoints */
+   colorspace->end_points_xy = sRGB_xy;
+   colorspace->end_points_XYZ = sRGB_XYZ;
+   colorspace->flags |=
+      (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
+
+   /* gamma */
+   colorspace->gamma = PNG_GAMMA_sRGB_INVERSE;
+   colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA;
+
+   /* Finally record that we have an sRGB profile */
+   colorspace->flags |=
+      (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB);
+
+   return 1; /* set */
+}
+#endif /* sRGB */
+
+#ifdef PNG_iCCP_SUPPORTED
+/* Encoded value of D50 as an ICC XYZNumber.  From the ICC 2010 spec the value
+ * is XYZ(0.9642,1.0,0.8249), which scales to:
+ *
+ *    (63189.8112, 65536, 54060.6464)
+ */
+static const png_byte D50_nCIEXYZ[12] =
+   { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d };
+
+static int /* bool */
+icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length)
+{
+   if (profile_length < 132)
+      return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+          "too short");
+   return 1;
+}
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+int /* PRIVATE */
+png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length)
+{
+   if (!icc_check_length(png_ptr, colorspace, name, profile_length))
+      return 0;
+
+   /* This needs to be here because the 'normal' check is in
+    * png_decompress_chunk, yet this happens after the attempt to
+    * png_malloc_base the required data.  We only need this on read; on write
+    * the caller supplies the profile buffer so libpng doesn't allocate it.  See
+    * the call to icc_check_length below (the write case).
+    */
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+      else if (png_ptr->user_chunk_malloc_max > 0 &&
+               png_ptr->user_chunk_malloc_max < profile_length)
+         return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+             "exceeds application limits");
+#  elif PNG_USER_CHUNK_MALLOC_MAX > 0
+      else if (PNG_USER_CHUNK_MALLOC_MAX < profile_length)
+         return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+             "exceeds libpng limits");
+#  else /* !SET_USER_LIMITS */
+      /* This will get compiled out on all 32-bit and better systems. */
+      else if (PNG_SIZE_MAX < profile_length)
+         return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+             "exceeds system limits");
+#  endif /* !SET_USER_LIMITS */
+
+   return 1;
+}
+#endif /* READ_iCCP */
+
+int /* PRIVATE */
+png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length,
+    png_const_bytep profile/* first 132 bytes only */, int color_type)
+{
+   png_uint_32 temp;
+
+   /* Length check; this cannot be ignored in this code because profile_length
+    * is used later to check the tag table, so even if the profile seems over
+    * long profile_length from the caller must be correct.  The caller can fix
+    * this up on read or write by just passing in the profile header length.
+    */
+   temp = png_get_uint_32(profile);
+   if (temp != profile_length)
+      return png_icc_profile_error(png_ptr, colorspace, name, temp,
+          "length does not match profile");
+
+   temp = (png_uint_32) (*(profile+8));
+   if (temp > 3 && (profile_length & 3))
+      return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+          "invalid length");
+
+   temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */
+   if (temp > 357913930 || /* (2^32-4-132)/12: maximum possible tag count */
+      profile_length < 132+12*temp) /* truncated tag table */
+      return png_icc_profile_error(png_ptr, colorspace, name, temp,
+          "tag count too large");
+
+   /* The 'intent' must be valid or we can't store it, ICC limits the intent to
+    * 16 bits.
+    */
+   temp = png_get_uint_32(profile+64);
+   if (temp >= 0xffff) /* The ICC limit */
+      return png_icc_profile_error(png_ptr, colorspace, name, temp,
+          "invalid rendering intent");
+
+   /* This is just a warning because the profile may be valid in future
+    * versions.
+    */
+   if (temp >= PNG_sRGB_INTENT_LAST)
+      (void)png_icc_profile_error(png_ptr, NULL, name, temp,
+          "intent outside defined range");
+
+   /* At this point the tag table can't be checked because it hasn't necessarily
+    * been loaded; however, various header fields can be checked.  These checks
+    * are for values permitted by the PNG spec in an ICC profile; the PNG spec
+    * restricts the profiles that can be passed in an iCCP chunk (they must be
+    * appropriate to processing PNG data!)
+    */
+
+   /* Data checks (could be skipped).  These checks must be independent of the
+    * version number; however, the version number doesn't accommodate changes in
+    * the header fields (just the known tags and the interpretation of the
+    * data.)
+    */
+   temp = png_get_uint_32(profile+36); /* signature 'ascp' */
+   if (temp != 0x61637370)
+      return png_icc_profile_error(png_ptr, colorspace, name, temp,
+          "invalid signature");
+
+   /* Currently the PCS illuminant/adopted white point (the computational
+    * white point) are required to be D50,
+    * however the profile contains a record of the illuminant so perhaps ICC
+    * expects to be able to change this in the future (despite the rationale in
+    * the introduction for using a fixed PCS adopted white.)  Consequently the
+    * following is just a warning.
+    */
+   if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0)
+      (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/,
+          "PCS illuminant is not D50");
+
+   /* The PNG spec requires this:
+    * "If the iCCP chunk is present, the image samples conform to the colour
+    * space represented by the embedded ICC profile as defined by the
+    * International Color Consortium [ICC]. The colour space of the ICC profile
+    * shall be an RGB colour space for colour images (PNG colour types 2, 3, and
+    * 6), or a greyscale colour space for greyscale images (PNG colour types 0
+    * and 4)."
+    *
+    * This checking code ensures the embedded profile (on either read or write)
+    * conforms to the specification requirements.  Notice that an ICC 'gray'
+    * color-space profile contains the information to transform the monochrome
+    * data to XYZ or L*a*b (according to which PCS the profile uses) and this
+    * should be used in preference to the standard libpng K channel replication
+    * into R, G and B channels.
+    *
+    * Previously it was suggested that an RGB profile on grayscale data could be
+    * handled.  However it it is clear that using an RGB profile in this context
+    * must be an error - there is no specification of what it means.  Thus it is
+    * almost certainly more correct to ignore the profile.
+    */
+   temp = png_get_uint_32(profile+16); /* data colour space field */
+   switch (temp)
+   {
+      case 0x52474220: /* 'RGB ' */
+         if ((color_type & PNG_COLOR_MASK_COLOR) == 0)
+            return png_icc_profile_error(png_ptr, colorspace, name, temp,
+                "RGB color space not permitted on grayscale PNG");
+         break;
+
+      case 0x47524159: /* 'GRAY' */
+         if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+            return png_icc_profile_error(png_ptr, colorspace, name, temp,
+                "Gray color space not permitted on RGB PNG");
+         break;
+
+      default:
+         return png_icc_profile_error(png_ptr, colorspace, name, temp,
+             "invalid ICC profile color space");
+   }
+
+   /* It is up to the application to check that the profile class matches the
+    * application requirements; the spec provides no guidance, but it's pretty
+    * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer
+    * ('prtr') or 'spac' (for generic color spaces).  Issue a warning in these
+    * cases.  Issue an error for device link or abstract profiles - these don't
+    * contain the records necessary to transform the color-space to anything
+    * other than the target device (and not even that for an abstract profile).
+    * Profiles of these classes may not be embedded in images.
+    */
+   temp = png_get_uint_32(profile+12); /* profile/device class */
+   switch (temp)
+   {
+      case 0x73636e72: /* 'scnr' */
+      case 0x6d6e7472: /* 'mntr' */
+      case 0x70727472: /* 'prtr' */
+      case 0x73706163: /* 'spac' */
+         /* All supported */
+         break;
+
+      case 0x61627374: /* 'abst' */
+         /* May not be embedded in an image */
+         return png_icc_profile_error(png_ptr, colorspace, name, temp,
+             "invalid embedded Abstract ICC profile");
+
+      case 0x6c696e6b: /* 'link' */
+         /* DeviceLink profiles cannot be interpreted in a non-device specific
+          * fashion, if an app uses the AToB0Tag in the profile the results are
+          * undefined unless the result is sent to the intended device,
+          * therefore a DeviceLink profile should not be found embedded in a
+          * PNG.
+          */
+         return png_icc_profile_error(png_ptr, colorspace, name, temp,
+             "unexpected DeviceLink ICC profile class");
+
+      case 0x6e6d636c: /* 'nmcl' */
+         /* A NamedColor profile is also device specific, however it doesn't
+          * contain an AToB0 tag that is open to misinterpretation.  Almost
+          * certainly it will fail the tests below.
+          */
+         (void)png_icc_profile_error(png_ptr, NULL, name, temp,
+             "unexpected NamedColor ICC profile class");
+         break;
+
+      default:
+         /* To allow for future enhancements to the profile accept unrecognized
+          * profile classes with a warning, these then hit the test below on the
+          * tag content to ensure they are backward compatible with one of the
+          * understood profiles.
+          */
+         (void)png_icc_profile_error(png_ptr, NULL, name, temp,
+             "unrecognized ICC profile class");
+         break;
+   }
+
+   /* For any profile other than a device link one the PCS must be encoded
+    * either in XYZ or Lab.
+    */
+   temp = png_get_uint_32(profile+20);
+   switch (temp)
+   {
+      case 0x58595a20: /* 'XYZ ' */
+      case 0x4c616220: /* 'Lab ' */
+         break;
+
+      default:
+         return png_icc_profile_error(png_ptr, colorspace, name, temp,
+             "unexpected ICC PCS encoding");
+   }
+
+   return 1;
+}
+
+int /* PRIVATE */
+png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length,
+    png_const_bytep profile /* header plus whole tag table */)
+{
+   png_uint_32 tag_count = png_get_uint_32(profile+128);
+   png_uint_32 itag;
+   png_const_bytep tag = profile+132; /* The first tag */
+
+   /* First scan all the tags in the table and add bits to the icc_info value
+    * (temporarily in 'tags').
+    */
+   for (itag=0; itag < tag_count; ++itag, tag += 12)
+   {
+      png_uint_32 tag_id = png_get_uint_32(tag+0);
+      png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */
+      png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */
+
+      /* The ICC specification does not exclude zero length tags, therefore the
+       * start might actually be anywhere if there is no data, but this would be
+       * a clear abuse of the intent of the standard so the start is checked for
+       * being in range.  All defined tag types have an 8 byte header - a 4 byte
+       * type signature then 0.
+       */
+
+      /* This is a hard error; potentially it can cause read outside the
+       * profile.
+       */
+      if (tag_start > profile_length || tag_length > profile_length - tag_start)
+         return png_icc_profile_error(png_ptr, colorspace, name, tag_id,
+             "ICC profile tag outside profile");
+
+      if ((tag_start & 3) != 0)
+      {
+         /* CNHP730S.icc shipped with Microsoft Windows 64 violates this; it is
+          * only a warning here because libpng does not care about the
+          * alignment.
+          */
+         (void)png_icc_profile_error(png_ptr, NULL, name, tag_id,
+             "ICC profile tag start not a multiple of 4");
+      }
+   }
+
+   return 1; /* success, maybe with warnings */
+}
+
+#ifdef PNG_sRGB_SUPPORTED
+#if PNG_sRGB_PROFILE_CHECKS >= 0
+/* Information about the known ICC sRGB profiles */
+static const struct
+{
+   png_uint_32 adler, crc, length;
+   png_uint_32 md5[4];
+   png_byte    have_md5;
+   png_byte    is_broken;
+   png_uint_16 intent;
+
+#  define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0)
+#  define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\
+      { adler, crc, length, md5, broke, intent },
+
+} png_sRGB_checks[] =
+{
+   /* This data comes from contrib/tools/checksum-icc run on downloads of
+    * all four ICC sRGB profiles from www.color.org.
+    */
+   /* adler32, crc32, MD5[4], intent, date, length, file-name */
+   PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9,
+       PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0,
+       "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc")
+
+   /* ICC sRGB v2 perceptual no black-compensation: */
+   PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21,
+       PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0,
+       "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc")
+
+   PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae,
+       PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0,
+       "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc")
+
+   /* ICC sRGB v4 perceptual */
+   PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812,
+       PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0,
+       "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc")
+
+   /* The following profiles have no known MD5 checksum. If there is a match
+    * on the (empty) MD5 the other fields are used to attempt a match and
+    * a warning is produced.  The first two of these profiles have a 'cprt' tag
+    * which suggests that they were also made by Hewlett Packard.
+    */
+   PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce,
+       PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0,
+       "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc")
+
+   /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not
+    * match the D50 PCS illuminant in the header (it is in fact the D65 values,
+    * so the white point is recorded as the un-adapted value.)  The profiles
+    * below only differ in one byte - the intent - and are basically the same as
+    * the previous profile except for the mediaWhitePointTag error and a missing
+    * chromaticAdaptationTag.
+    */
+   PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552,
+       PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/,
+       "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual")
+
+   PNG_ICC_CHECKSUM(0x0398f3fc, 0xf29e526d,
+       PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/,
+       "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative")
+};
+
+static int
+png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
+    png_const_bytep profile, uLong adler)
+{
+   /* The quick check is to verify just the MD5 signature and trust the
+    * rest of the data.  Because the profile has already been verified for
+    * correctness this is safe.  png_colorspace_set_sRGB will check the 'intent'
+    * field too, so if the profile has been edited with an intent not defined
+    * by sRGB (but maybe defined by a later ICC specification) the read of
+    * the profile will fail at that point.
+    */
+
+   png_uint_32 length = 0;
+   png_uint_32 intent = 0x10000; /* invalid */
+#if PNG_sRGB_PROFILE_CHECKS > 1
+   uLong crc = 0; /* the value for 0 length data */
+#endif
+   unsigned int i;
+
+#ifdef PNG_SET_OPTION_SUPPORTED
+   /* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */
+   if (((png_ptr->options >> PNG_SKIP_sRGB_CHECK_PROFILE) & 3) ==
+               PNG_OPTION_ON)
+      return 0;
+#endif
+
+   for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i)
+   {
+      if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] &&
+         png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] &&
+         png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] &&
+         png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3])
+      {
+         /* This may be one of the old HP profiles without an MD5, in that
+          * case we can only use the length and Adler32 (note that these
+          * are not used by default if there is an MD5!)
+          */
+#        if PNG_sRGB_PROFILE_CHECKS == 0
+            if (png_sRGB_checks[i].have_md5 != 0)
+               return 1+png_sRGB_checks[i].is_broken;
+#        endif
+
+         /* Profile is unsigned or more checks have been configured in. */
+         if (length == 0)
+         {
+            length = png_get_uint_32(profile);
+            intent = png_get_uint_32(profile+64);
+         }
+
+         /* Length *and* intent must match */
+         if (length == (png_uint_32) png_sRGB_checks[i].length &&
+            intent == (png_uint_32) png_sRGB_checks[i].intent)
+         {
+            /* Now calculate the adler32 if not done already. */
+            if (adler == 0)
+            {
+               adler = adler32(0, NULL, 0);
+               adler = adler32(adler, profile, length);
+            }
+
+            if (adler == png_sRGB_checks[i].adler)
+            {
+               /* These basic checks suggest that the data has not been
+                * modified, but if the check level is more than 1 perform
+                * our own crc32 checksum on the data.
+                */
+#              if PNG_sRGB_PROFILE_CHECKS > 1
+                  if (crc == 0)
+                  {
+                     crc = crc32(0, NULL, 0);
+                     crc = crc32(crc, profile, length);
+                  }
+
+                  /* So this check must pass for the 'return' below to happen.
+                   */
+                  if (crc == png_sRGB_checks[i].crc)
+#              endif
+               {
+                  if (png_sRGB_checks[i].is_broken != 0)
+                  {
+                     /* These profiles are known to have bad data that may cause
+                      * problems if they are used, therefore attempt to
+                      * discourage their use, skip the 'have_md5' warning below,
+                      * which is made irrelevant by this error.
+                      */
+                     png_chunk_report(png_ptr, "known incorrect sRGB profile",
+                         PNG_CHUNK_ERROR);
+                  }
+
+                  /* Warn that this being done; this isn't even an error since
+                   * the profile is perfectly valid, but it would be nice if
+                   * people used the up-to-date ones.
+                   */
+                  else if (png_sRGB_checks[i].have_md5 == 0)
+                  {
+                     png_chunk_report(png_ptr,
+                         "out-of-date sRGB profile with no signature",
+                         PNG_CHUNK_WARNING);
+                  }
+
+                  return 1+png_sRGB_checks[i].is_broken;
+               }
+            }
+
+# if PNG_sRGB_PROFILE_CHECKS > 0
+         /* The signature matched, but the profile had been changed in some
+          * way.  This probably indicates a data error or uninformed hacking.
+          * Fall through to "no match".
+          */
+         png_chunk_report(png_ptr,
+             "Not recognizing known sRGB profile that has been edited",
+             PNG_CHUNK_WARNING);
+         break;
+# endif
+         }
+      }
+   }
+
+   return 0; /* no match */
+}
+
+void /* PRIVATE */
+png_icc_set_sRGB(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, png_const_bytep profile, uLong adler)
+{
+   /* Is this profile one of the known ICC sRGB profiles?  If it is, just set
+    * the sRGB information.
+    */
+   if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler) != 0)
+      (void)png_colorspace_set_sRGB(png_ptr, colorspace,
+         (int)/*already checked*/png_get_uint_32(profile+64));
+}
+#endif /* PNG_sRGB_PROFILE_CHECKS >= 0 */
+#endif /* sRGB */
+
+int /* PRIVATE */
+png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace,
+    png_const_charp name, png_uint_32 profile_length, png_const_bytep profile,
+    int color_type)
+{
+   if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+      return 0;
+
+   if (icc_check_length(png_ptr, colorspace, name, profile_length) != 0 &&
+       png_icc_check_header(png_ptr, colorspace, name, profile_length, profile,
+           color_type) != 0 &&
+       png_icc_check_tag_table(png_ptr, colorspace, name, profile_length,
+           profile) != 0)
+   {
+#     if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
+         /* If no sRGB support, don't try storing sRGB information */
+         png_icc_set_sRGB(png_ptr, colorspace, profile, 0);
+#     endif
+      return 1;
+   }
+
+   /* Failure case */
+   return 0;
+}
+#endif /* iCCP */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+void /* PRIVATE */
+png_colorspace_set_rgb_coefficients(png_structrp png_ptr)
+{
+   /* Set the rgb_to_gray coefficients from the colorspace. */
+   if (png_ptr->rgb_to_gray_coefficients_set == 0 &&
+      (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      /* png_set_background has not been called, get the coefficients from the Y
+       * values of the colorspace colorants.
+       */
+      png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y;
+      png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y;
+      png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y;
+      png_fixed_point total = r+g+b;
+
+      if (total > 0 &&
+         r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 &&
+         g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 &&
+         b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 &&
+         r+g+b <= 32769)
+      {
+         /* We allow 0 coefficients here.  r+g+b may be 32769 if two or
+          * all of the coefficients were rounded up.  Handle this by
+          * reducing the *largest* coefficient by 1; this matches the
+          * approach used for the default coefficients in pngrtran.c
+          */
+         int add = 0;
+
+         if (r+g+b > 32768)
+            add = -1;
+         else if (r+g+b < 32768)
+            add = 1;
+
+         if (add != 0)
+         {
+            if (g >= r && g >= b)
+               g += add;
+            else if (r >= g && r >= b)
+               r += add;
+            else
+               b += add;
+         }
+
+         /* Check for an internal error. */
+         if (r+g+b != 32768)
+            png_error(png_ptr,
+                "internal error handling cHRM coefficients");
+
+         else
+         {
+            png_ptr->rgb_to_gray_red_coeff   = (png_uint_16)r;
+            png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
+         }
+      }
+
+      /* This is a png_error at present even though it could be ignored -
+       * it should never happen, but it is important that if it does, the
+       * bug is fixed.
+       */
+      else
+         png_error(png_ptr, "internal error handling cHRM->XYZ");
+   }
+}
+#endif /* READ_RGB_TO_GRAY */
+
+#endif /* COLORSPACE */
+
+void /* PRIVATE */
+png_check_IHDR(png_const_structrp png_ptr,
+    png_uint_32 width, png_uint_32 height, int bit_depth,
+    int color_type, int interlace_type, int compression_type,
+    int filter_type)
+{
+   int error = 0;
+
+   /* Check for width and height valid values */
+   if (width == 0)
+   {
+      png_warning(png_ptr, "Image width is zero in IHDR");
+      error = 1;
+   }
+
+   if (width > PNG_UINT_31_MAX)
+   {
+      png_warning(png_ptr, "Invalid image width in IHDR");
+      error = 1;
+   }
+
+   /* The bit mask on the first line below must be at least as big as a
+    * png_uint_32.  "~7U" is not adequate on 16-bit systems because it will
+    * be an unsigned 16-bit value.  Casting to (png_alloc_size_t) makes the
+    * type of the result at least as bit (in bits) as the RHS of the > operator
+    * which also avoids a common warning on 64-bit systems that the comparison
+    * of (png_uint_32) against the constant value on the RHS will always be
+    * false.
+    */
+   if (((width + 7) & ~(png_alloc_size_t)7) >
+       (((PNG_SIZE_MAX
+           - 48        /* big_row_buf hack */
+           - 1)        /* filter byte */
+           / 8)        /* 8-byte RGBA pixels */
+           - 1))       /* extra max_pixel_depth pad */
+   {
+      /* The size of the row must be within the limits of this architecture.
+       * Because the read code can perform arbitrary transformations the
+       * maximum size is checked here.  Because the code in png_read_start_row
+       * adds extra space "for safety's sake" in several places a conservative
+       * limit is used here.
+       *
+       * NOTE: it would be far better to check the size that is actually used,
+       * but the effect in the real world is minor and the changes are more
+       * extensive, therefore much more dangerous and much more difficult to
+       * write in a way that avoids compiler warnings.
+       */
+      png_warning(png_ptr, "Image width is too large for this architecture");
+      error = 1;
+   }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (width > png_ptr->user_width_max)
+#else
+   if (width > PNG_USER_WIDTH_MAX)
+#endif
+   {
+      png_warning(png_ptr, "Image width exceeds user limit in IHDR");
+      error = 1;
+   }
+
+   if (height == 0)
+   {
+      png_warning(png_ptr, "Image height is zero in IHDR");
+      error = 1;
+   }
+
+   if (height > PNG_UINT_31_MAX)
+   {
+      png_warning(png_ptr, "Invalid image height in IHDR");
+      error = 1;
+   }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (height > png_ptr->user_height_max)
+#else
+   if (height > PNG_USER_HEIGHT_MAX)
+#endif
+   {
+      png_warning(png_ptr, "Image height exceeds user limit in IHDR");
+      error = 1;
+   }
+
+   /* Check other values */
+   if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
+       bit_depth != 8 && bit_depth != 16)
+   {
+      png_warning(png_ptr, "Invalid bit depth in IHDR");
+      error = 1;
+   }
+
+   if (color_type < 0 || color_type == 1 ||
+       color_type == 5 || color_type > 6)
+   {
+      png_warning(png_ptr, "Invalid color type in IHDR");
+      error = 1;
+   }
+
+   if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
+       ((color_type == PNG_COLOR_TYPE_RGB ||
+         color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
+         color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
+   {
+      png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
+      error = 1;
+   }
+
+   if (interlace_type >= PNG_INTERLACE_LAST)
+   {
+      png_warning(png_ptr, "Unknown interlace method in IHDR");
+      error = 1;
+   }
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Unknown compression method in IHDR");
+      error = 1;
+   }
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   /* Accept filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not read a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 &&
+       png_ptr->mng_features_permitted != 0)
+      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
+
+   if (filter_type != PNG_FILTER_TYPE_BASE)
+   {
+      if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+          (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
+          ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
+          (color_type == PNG_COLOR_TYPE_RGB ||
+          color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+      {
+         png_warning(png_ptr, "Unknown filter method in IHDR");
+         error = 1;
+      }
+
+      if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0)
+      {
+         png_warning(png_ptr, "Invalid filter method in IHDR");
+         error = 1;
+      }
+   }
+
+#else
+   if (filter_type != PNG_FILTER_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Unknown filter method in IHDR");
+      error = 1;
+   }
+#endif
+
+   if (error == 1)
+      png_error(png_ptr, "Invalid IHDR data");
+}
+
+#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
+/* ASCII to fp functions */
+/* Check an ASCII formatted floating point value, see the more detailed
+ * comments in pngpriv.h
+ */
+/* The following is used internally to preserve the sticky flags */
+#define png_fp_add(state, flags) ((state) |= (flags))
+#define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY))
+
+int /* PRIVATE */
+png_check_fp_number(png_const_charp string, size_t size, int *statep,
+    size_t *whereami)
+{
+   int state = *statep;
+   size_t i = *whereami;
+
+   while (i < size)
+   {
+      int type;
+      /* First find the type of the next character */
+      switch (string[i])
+      {
+      case 43:  type = PNG_FP_SAW_SIGN;                   break;
+      case 45:  type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break;
+      case 46:  type = PNG_FP_SAW_DOT;                    break;
+      case 48:  type = PNG_FP_SAW_DIGIT;                  break;
+      case 49: case 50: case 51: case 52:
+      case 53: case 54: case 55: case 56:
+      case 57:  type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break;
+      case 69:
+      case 101: type = PNG_FP_SAW_E;                      break;
+      default:  goto PNG_FP_End;
+      }
+
+      /* Now deal with this type according to the current
+       * state, the type is arranged to not overlap the
+       * bits of the PNG_FP_STATE.
+       */
+      switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY))
+      {
+      case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
+         if ((state & PNG_FP_SAW_ANY) != 0)
+            goto PNG_FP_End; /* not a part of the number */
+
+         png_fp_add(state, type);
+         break;
+
+      case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
+         /* Ok as trailer, ok as lead of fraction. */
+         if ((state & PNG_FP_SAW_DOT) != 0) /* two dots */
+            goto PNG_FP_End;
+
+         else if ((state & PNG_FP_SAW_DIGIT) != 0) /* trailing dot? */
+            png_fp_add(state, type);
+
+         else
+            png_fp_set(state, PNG_FP_FRACTION | type);
+
+         break;
+
+      case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
+         if ((state & PNG_FP_SAW_DOT) != 0) /* delayed fraction */
+            png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);
+
+         png_fp_add(state, type | PNG_FP_WAS_VALID);
+
+         break;
+
+      case PNG_FP_INTEGER + PNG_FP_SAW_E:
+         if ((state & PNG_FP_SAW_DIGIT) == 0)
+            goto PNG_FP_End;
+
+         png_fp_set(state, PNG_FP_EXPONENT);
+
+         break;
+
+   /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN:
+         goto PNG_FP_End; ** no sign in fraction */
+
+   /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT:
+         goto PNG_FP_End; ** Because SAW_DOT is always set */
+
+      case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT:
+         png_fp_add(state, type | PNG_FP_WAS_VALID);
+         break;
+
+      case PNG_FP_FRACTION + PNG_FP_SAW_E:
+         /* This is correct because the trailing '.' on an
+          * integer is handled above - so we can only get here
+          * with the sequence ".E" (with no preceding digits).
+          */
+         if ((state & PNG_FP_SAW_DIGIT) == 0)
+            goto PNG_FP_End;
+
+         png_fp_set(state, PNG_FP_EXPONENT);
+
+         break;
+
+      case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
+         if ((state & PNG_FP_SAW_ANY) != 0)
+            goto PNG_FP_End; /* not a part of the number */
+
+         png_fp_add(state, PNG_FP_SAW_SIGN);
+
+         break;
+
+   /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT:
+         goto PNG_FP_End; */
+
+      case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT:
+         png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID);
+
+         break;
+
+   /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E:
+         goto PNG_FP_End; */
+
+      default: goto PNG_FP_End; /* I.e. break 2 */
+      }
+
+      /* The character seems ok, continue. */
+      ++i;
+   }
+
+PNG_FP_End:
+   /* Here at the end, update the state and return the correct
+    * return code.
+    */
+   *statep = state;
+   *whereami = i;
+
+   return (state & PNG_FP_SAW_DIGIT) != 0;
+}
+
+
+/* The same but for a complete string. */
+int
+png_check_fp_string(png_const_charp string, size_t size)
+{
+   int        state=0;
+   size_t char_index=0;
+
+   if (png_check_fp_number(string, size, &state, &char_index) != 0 &&
+      (char_index == size || string[char_index] == 0))
+      return state /* must be non-zero - see above */;
+
+   return 0; /* i.e. fail */
+}
+#endif /* pCAL || sCAL */
+
+#ifdef PNG_sCAL_SUPPORTED
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+/* Utility used below - a simple accurate power of ten from an integral
+ * exponent.
+ */
+static double
+png_pow10(int power)
+{
+   int recip = 0;
+   double d = 1;
+
+   /* Handle negative exponent with a reciprocal at the end because
+    * 10 is exact whereas .1 is inexact in base 2
+    */
+   if (power < 0)
+   {
+      if (power < DBL_MIN_10_EXP) return 0;
+      recip = 1; power = -power;
+   }
+
+   if (power > 0)
+   {
+      /* Decompose power bitwise. */
+      double mult = 10;
+      do
+      {
+         if (power & 1) d *= mult;
+         mult *= mult;
+         power >>= 1;
+      }
+      while (power > 0);
+
+      if (recip != 0) d = 1/d;
+   }
+   /* else power is 0 and d is 1 */
+
+   return d;
+}
+
+/* Function to format a floating point value in ASCII with a given
+ * precision.
+ */
+void /* PRIVATE */
+png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, size_t size,
+    double fp, unsigned int precision)
+{
+   /* We use standard functions from math.h, but not printf because
+    * that would require stdio.  The caller must supply a buffer of
+    * sufficient size or we will png_error.  The tests on size and
+    * the space in ascii[] consumed are indicated below.
+    */
+   if (precision < 1)
+      precision = DBL_DIG;
+
+   /* Enforce the limit of the implementation precision too. */
+   if (precision > DBL_DIG+1)
+      precision = DBL_DIG+1;
+
+   /* Basic sanity checks */
+   if (size >= precision+5) /* See the requirements below. */
+   {
+      if (fp < 0)
+      {
+         fp = -fp;
+         *ascii++ = 45; /* '-'  PLUS 1 TOTAL 1 */
+         --size;
+      }
+
+      if (fp >= DBL_MIN && fp <= DBL_MAX)
+      {
+         int exp_b10;   /* A base 10 exponent */
+         double base;   /* 10^exp_b10 */
+
+         /* First extract a base 10 exponent of the number,
+          * the calculation below rounds down when converting
+          * from base 2 to base 10 (multiply by log10(2) -
+          * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to
+          * be increased.  Note that the arithmetic shift
+          * performs a floor() unlike C arithmetic - using a
+          * C multiply would break the following for negative
+          * exponents.
+          */
+         (void)frexp(fp, &exp_b10); /* exponent to base 2 */
+
+         exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */
+
+         /* Avoid underflow here. */
+         base = png_pow10(exp_b10); /* May underflow */
+
+         while (base < DBL_MIN || base < fp)
+         {
+            /* And this may overflow. */
+            double test = png_pow10(exp_b10+1);
+
+            if (test <= DBL_MAX)
+            {
+               ++exp_b10; base = test;
+            }
+
+            else
+               break;
+         }
+
+         /* Normalize fp and correct exp_b10, after this fp is in the
+          * range [.1,1) and exp_b10 is both the exponent and the digit
+          * *before* which the decimal point should be inserted
+          * (starting with 0 for the first digit).  Note that this
+          * works even if 10^exp_b10 is out of range because of the
+          * test on DBL_MAX above.
+          */
+         fp /= base;
+         while (fp >= 1)
+         {
+            fp /= 10; ++exp_b10;
+         }
+
+         /* Because of the code above fp may, at this point, be
+          * less than .1, this is ok because the code below can
+          * handle the leading zeros this generates, so no attempt
+          * is made to correct that here.
+          */
+
+         {
+            unsigned int czero, clead, cdigits;
+            char exponent[10];
+
+            /* Allow up to two leading zeros - this will not lengthen
+             * the number compared to using E-n.
+             */
+            if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */
+            {
+               czero = 0U-exp_b10; /* PLUS 2 digits: TOTAL 3 */
+               exp_b10 = 0;      /* Dot added below before first output. */
+            }
+            else
+               czero = 0;    /* No zeros to add */
+
+            /* Generate the digit list, stripping trailing zeros and
+             * inserting a '.' before a digit if the exponent is 0.
+             */
+            clead = czero; /* Count of leading zeros */
+            cdigits = 0;   /* Count of digits in list. */
+
+            do
+            {
+               double d;
+
+               fp *= 10;
+               /* Use modf here, not floor and subtract, so that
+                * the separation is done in one step.  At the end
+                * of the loop don't break the number into parts so
+                * that the final digit is rounded.
+                */
+               if (cdigits+czero+1 < precision+clead)
+                  fp = modf(fp, &d);
+
+               else
+               {
+                  d = floor(fp + .5);
+
+                  if (d > 9)
+                  {
+                     /* Rounding up to 10, handle that here. */
+                     if (czero > 0)
+                     {
+                        --czero; d = 1;
+                        if (cdigits == 0) --clead;
+                     }
+                     else
+                     {
+                        while (cdigits > 0 && d > 9)
+                        {
+                           int ch = *--ascii;
+
+                           if (exp_b10 != (-1))
+                              ++exp_b10;
+
+                           else if (ch == 46)
+                           {
+                              ch = *--ascii; ++size;
+                              /* Advance exp_b10 to '1', so that the
+                               * decimal point happens after the
+                               * previous digit.
+                               */
+                              exp_b10 = 1;
+                           }
+
+                           --cdigits;
+                           d = ch - 47;  /* I.e. 1+(ch-48) */
+                        }
+
+                        /* Did we reach the beginning? If so adjust the
+                         * exponent but take into account the leading
+                         * decimal point.
+                         */
+                        if (d > 9)  /* cdigits == 0 */
+                        {
+                           if (exp_b10 == (-1))
+                           {
+                              /* Leading decimal point (plus zeros?), if
+                               * we lose the decimal point here it must
+                               * be reentered below.
+                               */
+                              int ch = *--ascii;
+
+                              if (ch == 46)
+                              {
+                                 ++size; exp_b10 = 1;
+                              }
+
+                              /* Else lost a leading zero, so 'exp_b10' is
+                               * still ok at (-1)
+                               */
+                           }
+                           else
+                              ++exp_b10;
+
+                           /* In all cases we output a '1' */
+                           d = 1;
+                        }
+                     }
+                  }
+                  fp = 0; /* Guarantees termination below. */
+               }
+
+               if (d == 0)
+               {
+                  ++czero;
+                  if (cdigits == 0) ++clead;
+               }
+               else
+               {
+                  /* Included embedded zeros in the digit count. */
+                  cdigits += czero - clead;
+                  clead = 0;
+
+                  while (czero > 0)
+                  {
+                     /* exp_b10 == (-1) means we just output the decimal
+                      * place - after the DP don't adjust 'exp_b10' any
+                      * more!
+                      */
+                     if (exp_b10 != (-1))
+                     {
+                        if (exp_b10 == 0)
+                        {
+                           *ascii++ = 46; --size;
+                        }
+                        /* PLUS 1: TOTAL 4 */
+                        --exp_b10;
+                     }
+                     *ascii++ = 48; --czero;
+                  }
+
+                  if (exp_b10 != (-1))
+                  {
+                     if (exp_b10 == 0)
+                     {
+                        *ascii++ = 46; --size; /* counted above */
+                     }
+
+                     --exp_b10;
+                  }
+                  *ascii++ = (char)(48 + (int)d); ++cdigits;
+               }
+            }
+            while (cdigits+czero < precision+clead && fp > DBL_MIN);
+
+            /* The total output count (max) is now 4+precision */
+
+            /* Check for an exponent, if we don't need one we are
+             * done and just need to terminate the string.  At this
+             * point, exp_b10==(-1) is effectively a flag: it got
+             * to '-1' because of the decrement, after outputting
+             * the decimal point above. (The exponent required is
+             * *not* -1.)
+             */
+            if (exp_b10 >= (-1) && exp_b10 <= 2)
+            {
+               /* The following only happens if we didn't output the
+                * leading zeros above for negative exponent, so this
+                * doesn't add to the digit requirement.  Note that the
+                * two zeros here can only be output if the two leading
+                * zeros were *not* output, so this doesn't increase
+                * the output count.
+                */
+               while (exp_b10-- > 0) *ascii++ = 48;
+
+               *ascii = 0;
+
+               /* Total buffer requirement (including the '\0') is
+                * 5+precision - see check at the start.
+                */
+               return;
+            }
+
+            /* Here if an exponent is required, adjust size for
+             * the digits we output but did not count.  The total
+             * digit output here so far is at most 1+precision - no
+             * decimal point and no leading or trailing zeros have
+             * been output.
+             */
+            size -= cdigits;
+
+            *ascii++ = 69; --size;    /* 'E': PLUS 1 TOTAL 2+precision */
+
+            /* The following use of an unsigned temporary avoids ambiguities in
+             * the signed arithmetic on exp_b10 and permits GCC at least to do
+             * better optimization.
+             */
+            {
+               unsigned int uexp_b10;
+
+               if (exp_b10 < 0)
+               {
+                  *ascii++ = 45; --size; /* '-': PLUS 1 TOTAL 3+precision */
+                  uexp_b10 = 0U-exp_b10;
+               }
+
+               else
+                  uexp_b10 = 0U+exp_b10;
+
+               cdigits = 0;
+
+               while (uexp_b10 > 0)
+               {
+                  exponent[cdigits++] = (char)(48 + uexp_b10 % 10);
+                  uexp_b10 /= 10;
+               }
+            }
+
+            /* Need another size check here for the exponent digits, so
+             * this need not be considered above.
+             */
+            if (size > cdigits)
+            {
+               while (cdigits > 0) *ascii++ = exponent[--cdigits];
+
+               *ascii = 0;
+
+               return;
+            }
+         }
+      }
+      else if (!(fp >= DBL_MIN))
+      {
+         *ascii++ = 48; /* '0' */
+         *ascii = 0;
+         return;
+      }
+      else
+      {
+         *ascii++ = 105; /* 'i' */
+         *ascii++ = 110; /* 'n' */
+         *ascii++ = 102; /* 'f' */
+         *ascii = 0;
+         return;
+      }
+   }
+
+   /* Here on buffer too small. */
+   png_error(png_ptr, "ASCII conversion buffer too small");
+}
+#  endif /* FLOATING_POINT */
+
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+/* Function to format a fixed point value in ASCII.
+ */
+void /* PRIVATE */
+png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
+    size_t size, png_fixed_point fp)
+{
+   /* Require space for 10 decimal digits, a decimal point, a minus sign and a
+    * trailing \0, 13 characters:
+    */
+   if (size > 12)
+   {
+      png_uint_32 num;
+
+      /* Avoid overflow here on the minimum integer. */
+      if (fp < 0)
+      {
+         *ascii++ = 45; num = (png_uint_32)(-fp);
+      }
+      else
+         num = (png_uint_32)fp;
+
+      if (num <= 0x80000000) /* else overflowed */
+      {
+         unsigned int ndigits = 0, first = 16 /* flag value */;
+         char digits[10] = {0};
+
+         while (num)
+         {
+            /* Split the low digit off num: */
+            unsigned int tmp = num/10;
+            num -= tmp*10;
+            digits[ndigits++] = (char)(48 + num);
+            /* Record the first non-zero digit, note that this is a number
+             * starting at 1, it's not actually the array index.
+             */
+            if (first == 16 && num > 0)
+               first = ndigits;
+            num = tmp;
+         }
+
+         if (ndigits > 0)
+         {
+            while (ndigits > 5) *ascii++ = digits[--ndigits];
+            /* The remaining digits are fractional digits, ndigits is '5' or
+             * smaller at this point.  It is certainly not zero.  Check for a
+             * non-zero fractional digit:
+             */
+            if (first <= 5)
+            {
+               unsigned int i;
+               *ascii++ = 46; /* decimal point */
+               /* ndigits may be <5 for small numbers, output leading zeros
+                * then ndigits digits to first:
+                */
+               i = 5;
+               while (ndigits < i)
+               {
+                  *ascii++ = 48; --i;
+               }
+               while (ndigits >= first) *ascii++ = digits[--ndigits];
+               /* Don't output the trailing zeros! */
+            }
+         }
+         else
+            *ascii++ = 48;
+
+         /* And null terminate the string: */
+         *ascii = 0;
+         return;
+      }
+   }
+
+   /* Here on buffer too small. */
+   png_error(png_ptr, "ASCII conversion buffer too small");
+}
+#   endif /* FIXED_POINT */
+#endif /* SCAL */
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
+   !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
+   (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
+   defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
+   (defined(PNG_sCAL_SUPPORTED) && \
+   defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
+png_fixed_point
+png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text)
+{
+   double r = floor(100000 * fp + .5);
+
+   if (r > 2147483647. || r < -2147483648.)
+      png_fixed_error(png_ptr, text);
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+   PNG_UNUSED(text)
+#  endif
+
+   return (png_fixed_point)r;
+}
+#endif
+
+#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_COLORSPACE_SUPPORTED) ||\
+    defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
+/* muldiv functions */
+/* This API takes signed arguments and rounds the result to the nearest
+ * integer (or, for a fixed point number - the standard argument - to
+ * the nearest .00001).  Overflow and divide by zero are signalled in
+ * the result, a boolean - true on success, false on overflow.
+ */
+int
+png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
+    png_int_32 divisor)
+{
+   /* Return a * times / divisor, rounded. */
+   if (divisor != 0)
+   {
+      if (a == 0 || times == 0)
+      {
+         *res = 0;
+         return 1;
+      }
+      else
+      {
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+         double r = a;
+         r *= times;
+         r /= divisor;
+         r = floor(r+.5);
+
+         /* A png_fixed_point is a 32-bit integer. */
+         if (r <= 2147483647. && r >= -2147483648.)
+         {
+            *res = (png_fixed_point)r;
+            return 1;
+         }
+#else
+         int negative = 0;
+         png_uint_32 A, T, D;
+         png_uint_32 s16, s32, s00;
+
+         if (a < 0)
+            negative = 1, A = -a;
+         else
+            A = a;
+
+         if (times < 0)
+            negative = !negative, T = -times;
+         else
+            T = times;
+
+         if (divisor < 0)
+            negative = !negative, D = -divisor;
+         else
+            D = divisor;
+
+         /* Following can't overflow because the arguments only
+          * have 31 bits each, however the result may be 32 bits.
+          */
+         s16 = (A >> 16) * (T & 0xffff) +
+                           (A & 0xffff) * (T >> 16);
+         /* Can't overflow because the a*times bit is only 30
+          * bits at most.
+          */
+         s32 = (A >> 16) * (T >> 16) + (s16 >> 16);
+         s00 = (A & 0xffff) * (T & 0xffff);
+
+         s16 = (s16 & 0xffff) << 16;
+         s00 += s16;
+
+         if (s00 < s16)
+            ++s32; /* carry */
+
+         if (s32 < D) /* else overflow */
+         {
+            /* s32.s00 is now the 64-bit product, do a standard
+             * division, we know that s32 < D, so the maximum
+             * required shift is 31.
+             */
+            int bitshift = 32;
+            png_fixed_point result = 0; /* NOTE: signed */
+
+            while (--bitshift >= 0)
+            {
+               png_uint_32 d32, d00;
+
+               if (bitshift > 0)
+                  d32 = D >> (32-bitshift), d00 = D << bitshift;
+
+               else
+                  d32 = 0, d00 = D;
+
+               if (s32 > d32)
+               {
+                  if (s00 < d00) --s32; /* carry */
+                  s32 -= d32, s00 -= d00, result += 1<<bitshift;
+               }
+
+               else
+                  if (s32 == d32 && s00 >= d00)
+                     s32 = 0, s00 -= d00, result += 1<<bitshift;
+            }
+
+            /* Handle the rounding. */
+            if (s00 >= (D >> 1))
+               ++result;
+
+            if (negative != 0)
+               result = -result;
+
+            /* Check for overflow. */
+            if ((negative != 0 && result <= 0) ||
+                (negative == 0 && result >= 0))
+            {
+               *res = result;
+               return 1;
+            }
+         }
+#endif
+      }
+   }
+
+   return 0;
+}
+#endif /* READ_GAMMA || INCH_CONVERSIONS */
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+/* The following is for when the caller doesn't much care about the
+ * result.
+ */
+png_fixed_point
+png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times,
+    png_int_32 divisor)
+{
+   png_fixed_point result;
+
+   if (png_muldiv(&result, a, times, divisor) != 0)
+      return result;
+
+   png_warning(png_ptr, "fixed point overflow ignored");
+   return 0;
+}
+#endif
+
+#ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */
+/* Calculate a reciprocal, return 0 on div-by-zero or overflow. */
+png_fixed_point
+png_reciprocal(png_fixed_point a)
+{
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+   double r = floor(1E10/a+.5);
+
+   if (r <= 2147483647. && r >= -2147483648.)
+      return (png_fixed_point)r;
+#else
+   png_fixed_point res;
+
+   if (png_muldiv(&res, 100000, 100000, a) != 0)
+      return res;
+#endif
+
+   return 0; /* error/overflow */
+}
+
+/* This is the shared test on whether a gamma value is 'significant' - whether
+ * it is worth doing gamma correction.
+ */
+int /* PRIVATE */
+png_gamma_significant(png_fixed_point gamma_val)
+{
+   return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED ||
+       gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
+}
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+#ifdef PNG_16BIT_SUPPORTED
+/* A local convenience routine. */
+static png_fixed_point
+png_product2(png_fixed_point a, png_fixed_point b)
+{
+   /* The required result is 1/a * 1/b; the following preserves accuracy. */
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+   double r = a * 1E-5;
+   r *= b;
+   r = floor(r+.5);
+
+   if (r <= 2147483647. && r >= -2147483648.)
+      return (png_fixed_point)r;
+#else
+   png_fixed_point res;
+
+   if (png_muldiv(&res, a, b, 100000) != 0)
+      return res;
+#endif
+
+   return 0; /* overflow */
+}
+#endif /* 16BIT */
+
+/* The inverse of the above. */
+png_fixed_point
+png_reciprocal2(png_fixed_point a, png_fixed_point b)
+{
+   /* The required result is 1/a * 1/b; the following preserves accuracy. */
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+   if (a != 0 && b != 0)
+   {
+      double r = 1E15/a;
+      r /= b;
+      r = floor(r+.5);
+
+      if (r <= 2147483647. && r >= -2147483648.)
+         return (png_fixed_point)r;
+   }
+#else
+   /* This may overflow because the range of png_fixed_point isn't symmetric,
+    * but this API is only used for the product of file and screen gamma so it
+    * doesn't matter that the smallest number it can produce is 1/21474, not
+    * 1/100000
+    */
+   png_fixed_point res = png_product2(a, b);
+
+   if (res != 0)
+      return png_reciprocal(res);
+#endif
+
+   return 0; /* overflow */
+}
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */
+#ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED
+/* Fixed point gamma.
+ *
+ * The code to calculate the tables used below can be found in the shell script
+ * contrib/tools/intgamma.sh
+ *
+ * To calculate gamma this code implements fast log() and exp() calls using only
+ * fixed point arithmetic.  This code has sufficient precision for either 8-bit
+ * or 16-bit sample values.
+ *
+ * The tables used here were calculated using simple 'bc' programs, but C double
+ * precision floating point arithmetic would work fine.
+ *
+ * 8-bit log table
+ *   This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
+ *   255, so it's the base 2 logarithm of a normalized 8-bit floating point
+ *   mantissa.  The numbers are 32-bit fractions.
+ */
+static const png_uint_32
+png_8bit_l2[128] =
+{
+   4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
+   3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
+   3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
+   3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U,
+   3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U,
+   2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U,
+   2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U,
+   2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U,
+   2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U,
+   2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U,
+   1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U,
+   1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U,
+   1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U,
+   1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U,
+   1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U,
+   971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U,
+   803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U,
+   639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U,
+   479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U,
+   324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
+   172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
+   24347096U, 0U
+
+#if 0
+   /* The following are the values for 16-bit tables - these work fine for the
+    * 8-bit conversions but produce very slightly larger errors in the 16-bit
+    * log (about 1.2 as opposed to 0.7 absolute error in the final value).  To
+    * use these all the shifts below must be adjusted appropriately.
+    */
+   65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
+   57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
+   50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068,
+   43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782,
+   37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887,
+   31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339,
+   25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098,
+   20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132,
+   15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415,
+   10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523,
+   6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495,
+   1119, 744, 372
+#endif
+};
+
+static png_int_32
+png_log8bit(unsigned int x)
+{
+   unsigned int lg2 = 0;
+   /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log,
+    * because the log is actually negate that means adding 1.  The final
+    * returned value thus has the range 0 (for 255 input) to 7.994 (for 1
+    * input), return -1 for the overflow (log 0) case, - so the result is
+    * always at most 19 bits.
+    */
+   if ((x &= 0xff) == 0)
+      return -1;
+
+   if ((x & 0xf0) == 0)
+      lg2  = 4, x <<= 4;
+
+   if ((x & 0xc0) == 0)
+      lg2 += 2, x <<= 2;
+
+   if ((x & 0x80) == 0)
+      lg2 += 1, x <<= 1;
+
+   /* result is at most 19 bits, so this cast is safe: */
+   return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16));
+}
+
+/* The above gives exact (to 16 binary places) log2 values for 8-bit images,
+ * for 16-bit images we use the most significant 8 bits of the 16-bit value to
+ * get an approximation then multiply the approximation by a correction factor
+ * determined by the remaining up to 8 bits.  This requires an additional step
+ * in the 16-bit case.
+ *
+ * We want log2(value/65535), we have log2(v'/255), where:
+ *
+ *    value = v' * 256 + v''
+ *          = v' * f
+ *
+ * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
+ * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
+ * than 258.  The final factor also needs to correct for the fact that our 8-bit
+ * value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
+ *
+ * This gives a final formula using a calculated value 'x' which is value/v' and
+ * scaling by 65536 to match the above table:
+ *
+ *   log2(x/257) * 65536
+ *
+ * Since these numbers are so close to '1' we can use simple linear
+ * interpolation between the two end values 256/257 (result -368.61) and 258/257
+ * (result 367.179).  The values used below are scaled by a further 64 to give
+ * 16-bit precision in the interpolation:
+ *
+ * Start (256): -23591
+ * Zero  (257):      0
+ * End   (258):  23499
+ */
+#ifdef PNG_16BIT_SUPPORTED
+static png_int_32
+png_log16bit(png_uint_32 x)
+{
+   unsigned int lg2 = 0;
+
+   /* As above, but now the input has 16 bits. */
+   if ((x &= 0xffff) == 0)
+      return -1;
+
+   if ((x & 0xff00) == 0)
+      lg2  = 8, x <<= 8;
+
+   if ((x & 0xf000) == 0)
+      lg2 += 4, x <<= 4;
+
+   if ((x & 0xc000) == 0)
+      lg2 += 2, x <<= 2;
+
+   if ((x & 0x8000) == 0)
+      lg2 += 1, x <<= 1;
+
+   /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
+    * value.
+    */
+   lg2 <<= 28;
+   lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4;
+
+   /* Now we need to interpolate the factor, this requires a division by the top
+    * 8 bits.  Do this with maximum precision.
+    */
+   x = ((x << 16) + (x >> 9)) / (x >> 8);
+
+   /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24,
+    * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly
+    * 16 bits to interpolate to get the low bits of the result.  Round the
+    * answer.  Note that the end point values are scaled by 64 to retain overall
+    * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust
+    * the overall scaling by 6-12.  Round at every step.
+    */
+   x -= 1U << 24;
+
+   if (x <= 65536U) /* <= '257' */
+      lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12);
+
+   else
+      lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12);
+
+   /* Safe, because the result can't have more than 20 bits: */
+   return (png_int_32)((lg2 + 2048) >> 12);
+}
+#endif /* 16BIT */
+
+/* The 'exp()' case must invert the above, taking a 20-bit fixed point
+ * logarithmic value and returning a 16 or 8-bit number as appropriate.  In
+ * each case only the low 16 bits are relevant - the fraction - since the
+ * integer bits (the top 4) simply determine a shift.
+ *
+ * The worst case is the 16-bit distinction between 65535 and 65534. This
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
+ * distinguish log2(65535/65534.5) - 10^-5 or 17 bits.  There is little chance
+ * of getting this accuracy in practice.
+ *
+ * To deal with this the following exp() function works out the exponent of the
+ * fractional part of the logarithm by using an accurate 32-bit value from the
+ * top four fractional bits then multiplying in the remaining bits.
+ */
+static const png_uint_32
+png_32bit_exp[16] =
+{
+   /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
+   4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
+   3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
+   2553802834U, 2445529972U, 2341847524U, 2242560872U
+};
+
+/* Adjustment table; provided to explain the numbers in the code below. */
+#if 0
+for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
+   11 44937.64284865548751208448
+   10 45180.98734845585101160448
+    9 45303.31936980687359311872
+    8 45364.65110595323018870784
+    7 45395.35850361789624614912
+    6 45410.72259715102037508096
+    5 45418.40724413220722311168
+    4 45422.25021786898173001728
+    3 45424.17186732298419044352
+    2 45425.13273269940811464704
+    1 45425.61317555035558641664
+    0 45425.85339951654943850496
+#endif
+
+static png_uint_32
+png_exp(png_fixed_point x)
+{
+   if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
+   {
+      /* Obtain a 4-bit approximation */
+      png_uint_32 e = png_32bit_exp[(x >> 12) & 0x0f];
+
+      /* Incorporate the low 12 bits - these decrease the returned value by
+       * multiplying by a number less than 1 if the bit is set.  The multiplier
+       * is determined by the above table and the shift. Notice that the values
+       * converge on 45426 and this is used to allow linear interpolation of the
+       * low bits.
+       */
+      if (x & 0x800)
+         e -= (((e >> 16) * 44938U) +  16U) >> 5;
+
+      if (x & 0x400)
+         e -= (((e >> 16) * 45181U) +  32U) >> 6;
+
+      if (x & 0x200)
+         e -= (((e >> 16) * 45303U) +  64U) >> 7;
+
+      if (x & 0x100)
+         e -= (((e >> 16) * 45365U) + 128U) >> 8;
+
+      if (x & 0x080)
+         e -= (((e >> 16) * 45395U) + 256U) >> 9;
+
+      if (x & 0x040)
+         e -= (((e >> 16) * 45410U) + 512U) >> 10;
+
+      /* And handle the low 6 bits in a single block. */
+      e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9;
+
+      /* Handle the upper bits of x. */
+      e >>= x >> 16;
+      return e;
+   }
+
+   /* Check for overflow */
+   if (x <= 0)
+      return png_32bit_exp[0];
+
+   /* Else underflow */
+   return 0;
+}
+
+static png_byte
+png_exp8bit(png_fixed_point lg2)
+{
+   /* Get a 32-bit value: */
+   png_uint_32 x = png_exp(lg2);
+
+   /* Convert the 32-bit value to 0..255 by multiplying by 256-1. Note that the
+    * second, rounding, step can't overflow because of the first, subtraction,
+    * step.
+    */
+   x -= x >> 8;
+   return (png_byte)(((x + 0x7fffffU) >> 24) & 0xff);
+}
+
+#ifdef PNG_16BIT_SUPPORTED
+static png_uint_16
+png_exp16bit(png_fixed_point lg2)
+{
+   /* Get a 32-bit value: */
+   png_uint_32 x = png_exp(lg2);
+
+   /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
+   x -= x >> 16;
+   return (png_uint_16)((x + 32767U) >> 16);
+}
+#endif /* 16BIT */
+#endif /* FLOATING_ARITHMETIC */
+
+png_byte
+png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
+{
+   if (value > 0 && value < 255)
+   {
+#     ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+         /* 'value' is unsigned, ANSI-C90 requires the compiler to correctly
+          * convert this to a floating point value.  This includes values that
+          * would overflow if 'value' were to be converted to 'int'.
+          *
+          * Apparently GCC, however, does an intermediate conversion to (int)
+          * on some (ARM) but not all (x86) platforms, possibly because of
+          * hardware FP limitations.  (E.g. if the hardware conversion always
+          * assumes the integer register contains a signed value.)  This results
+          * in ANSI-C undefined behavior for large values.
+          *
+          * Other implementations on the same machine might actually be ANSI-C90
+          * conformant and therefore compile spurious extra code for the large
+          * values.
+          *
+          * We can be reasonably sure that an unsigned to float conversion
+          * won't be faster than an int to float one.  Therefore this code
+          * assumes responsibility for the undefined behavior, which it knows
+          * can't happen because of the check above.
+          *
+          * Note the argument to this routine is an (unsigned int) because, on
+          * 16-bit platforms, it is assigned a value which might be out of
+          * range for an (int); that would result in undefined behavior in the
+          * caller if the *argument* ('value') were to be declared (int).
+          */
+         double r = floor(255*pow((int)/*SAFE*/value/255.,gamma_val*.00001)+.5);
+         return (png_byte)r;
+#     else
+         png_int_32 lg2 = png_log8bit(value);
+         png_fixed_point res;
+
+         if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
+            return png_exp8bit(res);
+
+         /* Overflow. */
+         value = 0;
+#     endif
+   }
+
+   return (png_byte)(value & 0xff);
+}
+
+#ifdef PNG_16BIT_SUPPORTED
+png_uint_16
+png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val)
+{
+   if (value > 0 && value < 65535)
+   {
+# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+      /* The same (unsigned int)->(double) constraints apply here as above,
+       * however in this case the (unsigned int) to (int) conversion can
+       * overflow on an ANSI-C90 compliant system so the cast needs to ensure
+       * that this is not possible.
+       */
+      double r = floor(65535*pow((png_int_32)value/65535.,
+          gamma_val*.00001)+.5);
+      return (png_uint_16)r;
+# else
+      png_int_32 lg2 = png_log16bit(value);
+      png_fixed_point res;
+
+      if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
+         return png_exp16bit(res);
+
+      /* Overflow. */
+      value = 0;
+# endif
+   }
+
+   return (png_uint_16)value;
+}
+#endif /* 16BIT */
+
+/* This does the right thing based on the bit_depth field of the
+ * png_struct, interpreting values as 8-bit or 16-bit.  While the result
+ * is nominally a 16-bit value if bit depth is 8 then the result is
+ * 8-bit (as are the arguments.)
+ */
+png_uint_16 /* PRIVATE */
+png_gamma_correct(png_structrp png_ptr, unsigned int value,
+    png_fixed_point gamma_val)
+{
+   if (png_ptr->bit_depth == 8)
+      return png_gamma_8bit_correct(value, gamma_val);
+
+#ifdef PNG_16BIT_SUPPORTED
+   else
+      return png_gamma_16bit_correct(value, gamma_val);
+#else
+      /* should not reach this */
+      return 0;
+#endif /* 16BIT */
+}
+
+#ifdef PNG_16BIT_SUPPORTED
+/* Internal function to build a single 16-bit table - the table consists of
+ * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
+ * to shift the input values right (or 16-number_of_signifiant_bits).
+ *
+ * The caller is responsible for ensuring that the table gets cleaned up on
+ * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument
+ * should be somewhere that will be cleaned.
+ */
+static void
+png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable,
+    unsigned int shift, png_fixed_point gamma_val)
+{
+   /* Various values derived from 'shift': */
+   unsigned int num = 1U << (8U - shift);
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+   /* CSE the division and work round wacky GCC warnings (see the comments
+    * in png_gamma_8bit_correct for where these come from.)
+    */
+   double fmax = 1.0 / (((png_int_32)1 << (16U - shift)) - 1);
+#endif
+   unsigned int max = (1U << (16U - shift)) - 1U;
+   unsigned int max_by_2 = 1U << (15U - shift);
+   unsigned int i;
+
+   png_uint_16pp table = *ptable =
+       (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
+
+   for (i = 0; i < num; i++)
+   {
+      png_uint_16p sub_table = table[i] =
+          (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16)));
+
+      /* The 'threshold' test is repeated here because it can arise for one of
+       * the 16-bit tables even if the others don't hit it.
+       */
+      if (png_gamma_significant(gamma_val) != 0)
+      {
+         /* The old code would overflow at the end and this would cause the
+          * 'pow' function to return a result >1, resulting in an
+          * arithmetic error.  This code follows the spec exactly; ig is
+          * the recovered input sample, it always has 8-16 bits.
+          *
+          * We want input * 65535/max, rounded, the arithmetic fits in 32
+          * bits (unsigned) so long as max <= 32767.
+          */
+         unsigned int j;
+         for (j = 0; j < 256; j++)
+         {
+            png_uint_32 ig = (j << (8-shift)) + i;
+#           ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+               /* Inline the 'max' scaling operation: */
+               /* See png_gamma_8bit_correct for why the cast to (int) is
+                * required here.
+                */
+               double d = floor(65535.*pow(ig*fmax, gamma_val*.00001)+.5);
+               sub_table[j] = (png_uint_16)d;
+#           else
+               if (shift != 0)
+                  ig = (ig * 65535U + max_by_2)/max;
+
+               sub_table[j] = png_gamma_16bit_correct(ig, gamma_val);
+#           endif
+         }
+      }
+      else
+      {
+         /* We must still build a table, but do it the fast way. */
+         unsigned int j;
+
+         for (j = 0; j < 256; j++)
+         {
+            png_uint_32 ig = (j << (8-shift)) + i;
+
+            if (shift != 0)
+               ig = (ig * 65535U + max_by_2)/max;
+
+            sub_table[j] = (png_uint_16)ig;
+         }
+      }
+   }
+}
+
+/* NOTE: this function expects the *inverse* of the overall gamma transformation
+ * required.
+ */
+static void
+png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable,
+    unsigned int shift, png_fixed_point gamma_val)
+{
+   unsigned int num = 1U << (8U - shift);
+   unsigned int max = (1U << (16U - shift))-1U;
+   unsigned int i;
+   png_uint_32 last;
+
+   png_uint_16pp table = *ptable =
+       (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
+
+   /* 'num' is the number of tables and also the number of low bits of low
+    * bits of the input 16-bit value used to select a table.  Each table is
+    * itself indexed by the high 8 bits of the value.
+    */
+   for (i = 0; i < num; i++)
+      table[i] = (png_uint_16p)png_malloc(png_ptr,
+          256 * (sizeof (png_uint_16)));
+
+   /* 'gamma_val' is set to the reciprocal of the value calculated above, so
+    * pow(out,g) is an *input* value.  'last' is the last input value set.
+    *
+    * In the loop 'i' is used to find output values.  Since the output is
+    * 8-bit there are only 256 possible values.  The tables are set up to
+    * select the closest possible output value for each input by finding
+    * the input value at the boundary between each pair of output values
+    * and filling the table up to that boundary with the lower output
+    * value.
+    *
+    * The boundary values are 0.5,1.5..253.5,254.5.  Since these are 9-bit
+    * values the code below uses a 16-bit value in i; the values start at
+    * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
+    * entries are filled with 255).  Start i at 128 and fill all 'last'
+    * table entries <= 'max'
+    */
+   last = 0;
+   for (i = 0; i < 255; ++i) /* 8-bit output value */
+   {
+      /* Find the corresponding maximum input value */
+      png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */
+
+      /* Find the boundary value in 16 bits: */
+      png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val);
+
+      /* Adjust (round) to (16-shift) bits: */
+      bound = (bound * max + 32768U)/65535U + 1U;
+
+      while (last < bound)
+      {
+         table[last & (0xffU >> shift)][last >> (8U - shift)] = out;
+         last++;
+      }
+   }
+
+   /* And fill in the final entries. */
+   while (last < (num << 8))
+   {
+      table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U;
+      last++;
+   }
+}
+#endif /* 16BIT */
+
+/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
+ * typically much faster).  Note that libpng currently does no sBIT processing
+ * (apparently contrary to the spec) so a 256-entry table is always generated.
+ */
+static void
+png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,
+    png_fixed_point gamma_val)
+{
+   unsigned int i;
+   png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256);
+
+   if (png_gamma_significant(gamma_val) != 0)
+      for (i=0; i<256; i++)
+         table[i] = png_gamma_8bit_correct(i, gamma_val);
+
+   else
+      for (i=0; i<256; ++i)
+         table[i] = (png_byte)(i & 0xff);
+}
+
+/* Used from png_read_destroy and below to release the memory used by the gamma
+ * tables.
+ */
+void /* PRIVATE */
+png_destroy_gamma_table(png_structrp png_ptr)
+{
+   png_free(png_ptr, png_ptr->gamma_table);
+   png_ptr->gamma_table = NULL;
+
+#ifdef PNG_16BIT_SUPPORTED
+   if (png_ptr->gamma_16_table != NULL)
+   {
+      int i;
+      int istop = (1 << (8 - png_ptr->gamma_shift));
+      for (i = 0; i < istop; i++)
+      {
+         png_free(png_ptr, png_ptr->gamma_16_table[i]);
+      }
+   png_free(png_ptr, png_ptr->gamma_16_table);
+   png_ptr->gamma_16_table = NULL;
+   }
+#endif /* 16BIT */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+   png_free(png_ptr, png_ptr->gamma_from_1);
+   png_ptr->gamma_from_1 = NULL;
+   png_free(png_ptr, png_ptr->gamma_to_1);
+   png_ptr->gamma_to_1 = NULL;
+
+#ifdef PNG_16BIT_SUPPORTED
+   if (png_ptr->gamma_16_from_1 != NULL)
+   {
+      int i;
+      int istop = (1 << (8 - png_ptr->gamma_shift));
+      for (i = 0; i < istop; i++)
+      {
+         png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
+      }
+   png_free(png_ptr, png_ptr->gamma_16_from_1);
+   png_ptr->gamma_16_from_1 = NULL;
+   }
+   if (png_ptr->gamma_16_to_1 != NULL)
+   {
+      int i;
+      int istop = (1 << (8 - png_ptr->gamma_shift));
+      for (i = 0; i < istop; i++)
+      {
+         png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
+      }
+   png_free(png_ptr, png_ptr->gamma_16_to_1);
+   png_ptr->gamma_16_to_1 = NULL;
+   }
+#endif /* 16BIT */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+}
+
+/* We build the 8- or 16-bit gamma tables here.  Note that for 16-bit
+ * tables, we don't make a full table if we are reducing to 8-bit in
+ * the future.  Note also how the gamma_16 tables are segmented so that
+ * we don't need to allocate > 64K chunks for a full 16-bit table.
+ */
+void /* PRIVATE */
+png_build_gamma_table(png_structrp png_ptr, int bit_depth)
+{
+   png_debug(1, "in png_build_gamma_table");
+
+   /* Remove any existing table; this copes with multiple calls to
+    * png_read_update_info. The warning is because building the gamma tables
+    * multiple times is a performance hit - it's harmless but the ability to
+    * call png_read_update_info() multiple times is new in 1.5.6 so it seems
+    * sensible to warn if the app introduces such a hit.
+    */
+   if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL)
+   {
+      png_warning(png_ptr, "gamma table being rebuilt");
+      png_destroy_gamma_table(png_ptr);
+   }
+
+   if (bit_depth <= 8)
+   {
+      png_build_8bit_table(png_ptr, &png_ptr->gamma_table,
+          png_ptr->screen_gamma > 0 ?
+          png_reciprocal2(png_ptr->colorspace.gamma,
+          png_ptr->screen_gamma) : PNG_FP_1);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+      if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
+      {
+         png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
+             png_reciprocal(png_ptr->colorspace.gamma));
+
+         png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1,
+             png_ptr->screen_gamma > 0 ?
+             png_reciprocal(png_ptr->screen_gamma) :
+             png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
+      }
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+   }
+#ifdef PNG_16BIT_SUPPORTED
+   else
+   {
+      png_byte shift, sig_bit;
+
+      if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      {
+         sig_bit = png_ptr->sig_bit.red;
+
+         if (png_ptr->sig_bit.green > sig_bit)
+            sig_bit = png_ptr->sig_bit.green;
+
+         if (png_ptr->sig_bit.blue > sig_bit)
+            sig_bit = png_ptr->sig_bit.blue;
+      }
+      else
+         sig_bit = png_ptr->sig_bit.gray;
+
+      /* 16-bit gamma code uses this equation:
+       *
+       *   ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
+       *
+       * Where 'iv' is the input color value and 'ov' is the output value -
+       * pow(iv, gamma).
+       *
+       * Thus the gamma table consists of up to 256 256-entry tables.  The table
+       * is selected by the (8-gamma_shift) most significant of the low 8 bits
+       * of the color value then indexed by the upper 8 bits:
+       *
+       *   table[low bits][high 8 bits]
+       *
+       * So the table 'n' corresponds to all those 'iv' of:
+       *
+       *   <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
+       *
+       */
+      if (sig_bit > 0 && sig_bit < 16U)
+         /* shift == insignificant bits */
+         shift = (png_byte)((16U - sig_bit) & 0xff);
+
+      else
+         shift = 0; /* keep all 16 bits */
+
+      if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
+      {
+         /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
+          * the significant bits in the *input* when the output will
+          * eventually be 8 bits.  By default it is 11.
+          */
+         if (shift < (16U - PNG_MAX_GAMMA_8))
+            shift = (16U - PNG_MAX_GAMMA_8);
+      }
+
+      if (shift > 8U)
+         shift = 8U; /* Guarantees at least one table! */
+
+      png_ptr->gamma_shift = shift;
+
+      /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now
+       * PNG_COMPOSE).  This effectively smashed the background calculation for
+       * 16-bit output because the 8-bit table assumes the result will be
+       * reduced to 8 bits.
+       */
+      if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
+          png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
+          png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma,
+          png_ptr->screen_gamma) : PNG_FP_1);
+
+      else
+          png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift,
+          png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma,
+          png_ptr->screen_gamma) : PNG_FP_1);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+      if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
+      {
+         png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
+             png_reciprocal(png_ptr->colorspace.gamma));
+
+         /* Notice that the '16 from 1' table should be full precision, however
+          * the lookup on this table still uses gamma_shift, so it can't be.
+          * TODO: fix this.
+          */
+         png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift,
+             png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
+             png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
+      }
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+   }
+#endif /* 16BIT */
+}
+#endif /* READ_GAMMA */
+
+/* HARDWARE OR SOFTWARE OPTION SUPPORT */
+#ifdef PNG_SET_OPTION_SUPPORTED
+int PNGAPI
+png_set_option(png_structrp png_ptr, int option, int onoff)
+{
+   if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
+      (option & 1) == 0)
+   {
+      png_uint_32 mask = 3U << option;
+      png_uint_32 setting = (2U + (onoff != 0)) << option;
+      png_uint_32 current = png_ptr->options;
+
+      png_ptr->options = (png_uint_32)((current & ~mask) | setting);
+
+      return (int)(current & mask) >> option;
+   }
+
+   return PNG_OPTION_INVALID;
+}
+#endif
+
+/* sRGB support */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+/* sRGB conversion tables; these are machine generated with the code in
+ * contrib/tools/makesRGB.c.  The actual sRGB transfer curve defined in the
+ * specification (see the article at https://en.wikipedia.org/wiki/SRGB)
+ * is used, not the gamma=1/2.2 approximation use elsewhere in libpng.
+ * The sRGB to linear table is exact (to the nearest 16-bit linear fraction).
+ * The inverse (linear to sRGB) table has accuracies as follows:
+ *
+ * For all possible (255*65535+1) input values:
+ *
+ *    error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact
+ *
+ * For the input values corresponding to the 65536 16-bit values:
+ *
+ *    error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact
+ *
+ * In all cases the inexact readings are only off by one.
+ */
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+/* The convert-to-sRGB table is only currently required for read. */
+const png_uint_16 png_sRGB_table[256] =
+{
+   0,20,40,60,80,99,119,139,
+   159,179,199,219,241,264,288,313,
+   340,367,396,427,458,491,526,562,
+   599,637,677,718,761,805,851,898,
+   947,997,1048,1101,1156,1212,1270,1330,
+   1391,1453,1517,1583,1651,1720,1790,1863,
+   1937,2013,2090,2170,2250,2333,2418,2504,
+   2592,2681,2773,2866,2961,3058,3157,3258,
+   3360,3464,3570,3678,3788,3900,4014,4129,
+   4247,4366,4488,4611,4736,4864,4993,5124,
+   5257,5392,5530,5669,5810,5953,6099,6246,
+   6395,6547,6700,6856,7014,7174,7335,7500,
+   7666,7834,8004,8177,8352,8528,8708,8889,
+   9072,9258,9445,9635,9828,10022,10219,10417,
+   10619,10822,11028,11235,11446,11658,11873,12090,
+   12309,12530,12754,12980,13209,13440,13673,13909,
+   14146,14387,14629,14874,15122,15371,15623,15878,
+   16135,16394,16656,16920,17187,17456,17727,18001,
+   18277,18556,18837,19121,19407,19696,19987,20281,
+   20577,20876,21177,21481,21787,22096,22407,22721,
+   23038,23357,23678,24002,24329,24658,24990,25325,
+   25662,26001,26344,26688,27036,27386,27739,28094,
+   28452,28813,29176,29542,29911,30282,30656,31033,
+   31412,31794,32179,32567,32957,33350,33745,34143,
+   34544,34948,35355,35764,36176,36591,37008,37429,
+   37852,38278,38706,39138,39572,40009,40449,40891,
+   41337,41785,42236,42690,43147,43606,44069,44534,
+   45002,45473,45947,46423,46903,47385,47871,48359,
+   48850,49344,49841,50341,50844,51349,51858,52369,
+   52884,53401,53921,54445,54971,55500,56032,56567,
+   57105,57646,58190,58737,59287,59840,60396,60955,
+   61517,62082,62650,63221,63795,64372,64952,65535
+};
+#endif /* SIMPLIFIED_READ */
+
+/* The base/delta tables are required for both read and write (but currently
+ * only the simplified versions.)
+ */
+const png_uint_16 png_sRGB_base[512] =
+{
+   128,1782,3383,4644,5675,6564,7357,8074,
+   8732,9346,9921,10463,10977,11466,11935,12384,
+   12816,13233,13634,14024,14402,14769,15125,15473,
+   15812,16142,16466,16781,17090,17393,17690,17981,
+   18266,18546,18822,19093,19359,19621,19879,20133,
+   20383,20630,20873,21113,21349,21583,21813,22041,
+   22265,22487,22707,22923,23138,23350,23559,23767,
+   23972,24175,24376,24575,24772,24967,25160,25352,
+   25542,25730,25916,26101,26284,26465,26645,26823,
+   27000,27176,27350,27523,27695,27865,28034,28201,
+   28368,28533,28697,28860,29021,29182,29341,29500,
+   29657,29813,29969,30123,30276,30429,30580,30730,
+   30880,31028,31176,31323,31469,31614,31758,31902,
+   32045,32186,32327,32468,32607,32746,32884,33021,
+   33158,33294,33429,33564,33697,33831,33963,34095,
+   34226,34357,34486,34616,34744,34873,35000,35127,
+   35253,35379,35504,35629,35753,35876,35999,36122,
+   36244,36365,36486,36606,36726,36845,36964,37083,
+   37201,37318,37435,37551,37668,37783,37898,38013,
+   38127,38241,38354,38467,38580,38692,38803,38915,
+   39026,39136,39246,39356,39465,39574,39682,39790,
+   39898,40005,40112,40219,40325,40431,40537,40642,
+   40747,40851,40955,41059,41163,41266,41369,41471,
+   41573,41675,41777,41878,41979,42079,42179,42279,
+   42379,42478,42577,42676,42775,42873,42971,43068,
+   43165,43262,43359,43456,43552,43648,43743,43839,
+   43934,44028,44123,44217,44311,44405,44499,44592,
+   44685,44778,44870,44962,45054,45146,45238,45329,
+   45420,45511,45601,45692,45782,45872,45961,46051,
+   46140,46229,46318,46406,46494,46583,46670,46758,
+   46846,46933,47020,47107,47193,47280,47366,47452,
+   47538,47623,47709,47794,47879,47964,48048,48133,
+   48217,48301,48385,48468,48552,48635,48718,48801,
+   48884,48966,49048,49131,49213,49294,49376,49458,
+   49539,49620,49701,49782,49862,49943,50023,50103,
+   50183,50263,50342,50422,50501,50580,50659,50738,
+   50816,50895,50973,51051,51129,51207,51285,51362,
+   51439,51517,51594,51671,51747,51824,51900,51977,
+   52053,52129,52205,52280,52356,52432,52507,52582,
+   52657,52732,52807,52881,52956,53030,53104,53178,
+   53252,53326,53400,53473,53546,53620,53693,53766,
+   53839,53911,53984,54056,54129,54201,54273,54345,
+   54417,54489,54560,54632,54703,54774,54845,54916,
+   54987,55058,55129,55199,55269,55340,55410,55480,
+   55550,55620,55689,55759,55828,55898,55967,56036,
+   56105,56174,56243,56311,56380,56448,56517,56585,
+   56653,56721,56789,56857,56924,56992,57059,57127,
+   57194,57261,57328,57395,57462,57529,57595,57662,
+   57728,57795,57861,57927,57993,58059,58125,58191,
+   58256,58322,58387,58453,58518,58583,58648,58713,
+   58778,58843,58908,58972,59037,59101,59165,59230,
+   59294,59358,59422,59486,59549,59613,59677,59740,
+   59804,59867,59930,59993,60056,60119,60182,60245,
+   60308,60370,60433,60495,60558,60620,60682,60744,
+   60806,60868,60930,60992,61054,61115,61177,61238,
+   61300,61361,61422,61483,61544,61605,61666,61727,
+   61788,61848,61909,61969,62030,62090,62150,62211,
+   62271,62331,62391,62450,62510,62570,62630,62689,
+   62749,62808,62867,62927,62986,63045,63104,63163,
+   63222,63281,63340,63398,63457,63515,63574,63632,
+   63691,63749,63807,63865,63923,63981,64039,64097,
+   64155,64212,64270,64328,64385,64443,64500,64557,
+   64614,64672,64729,64786,64843,64900,64956,65013,
+   65070,65126,65183,65239,65296,65352,65409,65465
+};
+
+const png_byte png_sRGB_delta[512] =
+{
+   207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54,
+   52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36,
+   35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28,
+   28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24,
+   23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21,
+   21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19,
+   19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17,
+   17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16,
+   16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15,
+   15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14,
+   14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13,
+   13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12,
+   12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,
+   12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11,
+   11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
+   11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
+   11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+   10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+   10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+   10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+   9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+   9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+   9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+   9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+   8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7,
+   7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+   7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+   7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
+};
+#endif /* SIMPLIFIED READ/WRITE sRGB support */
+
+/* SIMPLIFIED READ/WRITE SUPPORT */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+static int
+png_image_free_function(png_voidp argument)
+{
+   png_imagep image = png_voidcast(png_imagep, argument);
+   png_controlp cp = image->opaque;
+   png_control c;
+
+   /* Double check that we have a png_ptr - it should be impossible to get here
+    * without one.
+    */
+   if (cp->png_ptr == NULL)
+      return 0;
+
+   /* First free any data held in the control structure. */
+#  ifdef PNG_STDIO_SUPPORTED
+      if (cp->owned_file != 0)
+      {
+         FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr);
+         cp->owned_file = 0;
+
+         /* Ignore errors here. */
+         if (fp != NULL)
+         {
+            cp->png_ptr->io_ptr = NULL;
+            (void)fclose(fp);
+         }
+      }
+#  endif
+
+   /* Copy the control structure so that the original, allocated, version can be
+    * safely freed.  Notice that a png_error here stops the remainder of the
+    * cleanup, but this is probably fine because that would indicate bad memory
+    * problems anyway.
+    */
+   c = *cp;
+   image->opaque = &c;
+   png_free(c.png_ptr, cp);
+
+   /* Then the structures, calling the correct API. */
+   if (c.for_write != 0)
+   {
+#     ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+         png_destroy_write_struct(&c.png_ptr, &c.info_ptr);
+#     else
+         png_error(c.png_ptr, "simplified write not supported");
+#     endif
+   }
+   else
+   {
+#     ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+         png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL);
+#     else
+         png_error(c.png_ptr, "simplified read not supported");
+#     endif
+   }
+
+   /* Success. */
+   return 1;
+}
+
+void PNGAPI
+png_image_free(png_imagep image)
+{
+   /* Safely call the real function, but only if doing so is safe at this point
+    * (if not inside an error handling context).  Otherwise assume
+    * png_safe_execute will call this API after the return.
+    */
+   if (image != NULL && image->opaque != NULL &&
+      image->opaque->error_buf == NULL)
+   {
+      png_image_free_function(image);
+      image->opaque = NULL;
+   }
+}
+
+int /* PRIVATE */
+png_image_error(png_imagep image, png_const_charp error_message)
+{
+   /* Utility to log an error. */
+   png_safecat(image->message, (sizeof image->message), 0, error_message);
+   image->warning_or_error |= PNG_IMAGE_ERROR;
+   png_image_free(image);
+   return 0;
+}
+
+#endif /* SIMPLIFIED READ/WRITE */
+#endif /* READ || WRITE */
Index: /trunk/src/libs/libpng-1.6.45/png.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/png.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/png.h	(revision 107811)
@@ -0,0 +1,3250 @@
+
+/* png.h - header file for PNG reference library
+ *
+ * libpng version 1.6.43
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license. (See LICENSE, below.)
+ *
+ * Authors and maintainers:
+ *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
+ *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
+ *   libpng versions 0.97, January 1998, through 1.6.35, July 2018:
+ *     Glenn Randers-Pehrson
+ *   libpng versions 1.6.36, December 2018, through 1.6.43, February 2024:
+ *     Cosmin Truta
+ *   See also "Contributing Authors", below.
+ */
+
+/*
+ * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
+ * =========================================
+ *
+ * PNG Reference Library License version 2
+ * ---------------------------------------
+ *
+ *  * Copyright (c) 1995-2024 The PNG Reference Library Authors.
+ *  * Copyright (c) 2018-2024 Cosmin Truta.
+ *  * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson.
+ *  * Copyright (c) 1996-1997 Andreas Dilger.
+ *  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * The software is supplied "as is", without warranty of any kind,
+ * express or implied, including, without limitation, the warranties
+ * of merchantability, fitness for a particular purpose, title, and
+ * non-infringement.  In no event shall the Copyright owners, or
+ * anyone distributing the software, be liable for any damages or
+ * other liability, whether in contract, tort or otherwise, arising
+ * from, out of, or in connection with the software, or the use or
+ * other dealings in the software, even if advised of the possibility
+ * of such damage.
+ *
+ * Permission is hereby granted to use, copy, modify, and distribute
+ * this software, or portions hereof, for any purpose, without fee,
+ * subject to the following restrictions:
+ *
+ *  1. The origin of this software must not be misrepresented; you
+ *     must not claim that you wrote the original software.  If you
+ *     use this software in a product, an acknowledgment in the product
+ *     documentation would be appreciated, but is not required.
+ *
+ *  2. Altered source versions must be plainly marked as such, and must
+ *     not be misrepresented as being the original software.
+ *
+ *  3. This Copyright notice may not be removed or altered from any
+ *     source or altered source distribution.
+ *
+ *
+ * PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
+ * -----------------------------------------------------------------------
+ *
+ * libpng versions 1.0.7, July 1, 2000, through 1.6.35, July 15, 2018 are
+ * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson, are
+ * derived from libpng-1.0.6, and are distributed according to the same
+ * disclaimer and license as libpng-1.0.6 with the following individuals
+ * added to the list of Contributing Authors:
+ *
+ *     Simon-Pierre Cadieux
+ *     Eric S. Raymond
+ *     Mans Rullgard
+ *     Cosmin Truta
+ *     Gilles Vollant
+ *     James Yu
+ *     Mandar Sahastrabuddhe
+ *     Google Inc.
+ *     Vadim Barkov
+ *
+ * and with the following additions to the disclaimer:
+ *
+ *     There is no warranty against interference with your enjoyment of
+ *     the library or against infringement.  There is no warranty that our
+ *     efforts or the library will fulfill any of your particular purposes
+ *     or needs.  This library is provided with all faults, and the entire
+ *     risk of satisfactory quality, performance, accuracy, and effort is
+ *     with the user.
+ *
+ * Some files in the "contrib" directory and some configure-generated
+ * files that are distributed with libpng have other copyright owners, and
+ * are released under other open source licenses.
+ *
+ * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
+ * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
+ * libpng-0.96, and are distributed according to the same disclaimer and
+ * license as libpng-0.96, with the following individuals added to the
+ * list of Contributing Authors:
+ *
+ *     Tom Lane
+ *     Glenn Randers-Pehrson
+ *     Willem van Schaik
+ *
+ * libpng versions 0.89, June 1996, through 0.96, May 1997, are
+ * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
+ * and are distributed according to the same disclaimer and license as
+ * libpng-0.88, with the following individuals added to the list of
+ * Contributing Authors:
+ *
+ *     John Bowler
+ *     Kevin Bracey
+ *     Sam Bushell
+ *     Magnus Holmgren
+ *     Greg Roelofs
+ *     Tom Tanner
+ *
+ * Some files in the "scripts" directory have other copyright owners,
+ * but are released under this license.
+ *
+ * libpng versions 0.5, May 1995, through 0.88, January 1996, are
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * For the purposes of this copyright and license, "Contributing Authors"
+ * is defined as the following set of individuals:
+ *
+ *     Andreas Dilger
+ *     Dave Martindale
+ *     Guy Eric Schalnat
+ *     Paul Schmidt
+ *     Tim Wegner
+ *
+ * The PNG Reference Library is supplied "AS IS".  The Contributing
+ * Authors and Group 42, Inc. disclaim all warranties, expressed or
+ * implied, including, without limitation, the warranties of
+ * merchantability and of fitness for any purpose.  The Contributing
+ * Authors and Group 42, Inc. assume no liability for direct, indirect,
+ * incidental, special, exemplary, or consequential damages, which may
+ * result from the use of the PNG Reference Library, even if advised of
+ * the possibility of such damage.
+ *
+ * Permission is hereby granted to use, copy, modify, and distribute this
+ * source code, or portions hereof, for any purpose, without fee, subject
+ * to the following restrictions:
+ *
+ *  1. The origin of this source code must not be misrepresented.
+ *
+ *  2. Altered versions must be plainly marked as such and must not
+ *     be misrepresented as being the original source.
+ *
+ *  3. This Copyright notice may not be removed or altered from any
+ *     source or altered source distribution.
+ *
+ * The Contributing Authors and Group 42, Inc. specifically permit,
+ * without fee, and encourage the use of this source code as a component
+ * to supporting the PNG file format in commercial products.  If you use
+ * this source code in a product, acknowledgment is not required but would
+ * be appreciated.
+ *
+ * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
+ *
+ * TRADEMARK
+ * =========
+ *
+ * The name "libpng" has not been registered by the Copyright owners
+ * as a trademark in any jurisdiction.  However, because libpng has
+ * been distributed and maintained world-wide, continually since 1995,
+ * the Copyright owners claim "common-law trademark protection" in any
+ * jurisdiction where common-law trademark is recognized.
+ */
+
+/*
+ * A "png_get_copyright" function is available, for convenient use in "about"
+ * boxes and the like:
+ *
+ *    printf("%s", png_get_copyright(NULL));
+ *
+ * Also, the PNG logo (in PNG format, of course) is supplied in the
+ * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
+ */
+
+/*
+ * The contributing authors would like to thank all those who helped
+ * with testing, bug fixes, and patience.  This wouldn't have been
+ * possible without all of you.
+ *
+ * Thanks to Frank J. T. Wojcik for helping with the documentation.
+ */
+
+/* Note about libpng version numbers:
+ *
+ *    Due to various miscommunications, unforeseen code incompatibilities
+ *    and occasional factors outside the authors' control, version numbering
+ *    on the library has not always been consistent and straightforward.
+ *    The following table summarizes matters since version 0.89c, which was
+ *    the first widely used release:
+ *
+ *    source                 png.h  png.h  shared-lib
+ *    version                string   int  version
+ *    -------                ------ -----  ----------
+ *    0.89c "1.0 beta 3"     0.89      89  1.0.89
+ *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
+ *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
+ *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
+ *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
+ *    0.97c                  0.97      97  2.0.97
+ *    0.98                   0.98      98  2.0.98
+ *    0.99                   0.99      98  2.0.99
+ *    0.99a-m                0.99      99  2.0.99
+ *    1.00                   1.00     100  2.1.0 [100 should be 10000]
+ *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
+ *    1.0.1       png.h string is   10001  2.1.0
+ *    1.0.1a-e    identical to the  10002  from here on, the shared library
+ *    1.0.2       source version)   10002  is 2.V where V is the source code
+ *    1.0.2a-b                      10003  version, except as noted.
+ *    1.0.3                         10003
+ *    1.0.3a-d                      10004
+ *    1.0.4                         10004
+ *    1.0.4a-f                      10005
+ *    1.0.5 (+ 2 patches)           10005
+ *    1.0.5a-d                      10006
+ *    1.0.5e-r                      10100 (not source compatible)
+ *    1.0.5s-v                      10006 (not binary compatible)
+ *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)
+ *    1.0.6d-f                      10007 (still binary incompatible)
+ *    1.0.6g                        10007
+ *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)
+ *    1.0.6i                        10007  10.6i
+ *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
+ *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
+ *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
+ *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
+ *    1.0.7                    1    10007  (still compatible)
+ *    ...
+ *    1.0.69                  10    10069  10.so.0.69[.0]
+ *    ...
+ *    1.2.59                  13    10259  12.so.0.59[.0]
+ *    ...
+ *    1.4.20                  14    10420  14.so.0.20[.0]
+ *    ...
+ *    1.5.30                  15    10530  15.so.15.30[.0]
+ *    ...
+ *    1.6.43                  16    10643  16.so.16.43[.0]
+ *
+ *    Henceforth the source version will match the shared-library major and
+ *    minor numbers; the shared-library major version number will be used for
+ *    changes in backward compatibility, as it is intended.
+ *    The PNG_LIBPNG_VER macro, which is not used within libpng but is
+ *    available for applications, is an unsigned integer of the form XYYZZ
+ *    corresponding to the source version X.Y.Z (leading zeros in Y and Z).
+ *    Beta versions were given the previous public release number plus a
+ *    letter, until version 1.0.6j; from then on they were given the upcoming
+ *    public release number plus "betaNN" or "rcNN".
+ *
+ *    Binary incompatibility exists only when applications make direct access
+ *    to the info_ptr or png_ptr members through png.h, and the compiled
+ *    application is loaded with a different version of the library.
+ *
+ * See libpng.txt or libpng.3 for more information.  The PNG specification
+ * is available as a W3C Recommendation and as an ISO/IEC Standard; see
+ * <https://www.w3.org/TR/2003/REC-PNG-20031110/>
+ */
+
+#ifndef PNG_H
+#define PNG_H
+
+/* This is not the place to learn how to use libpng. The file libpng-manual.txt
+ * describes how to use libpng, and the file example.c summarizes it
+ * with some code on which to build.  This file is useful for looking
+ * at the actual function definitions and structure components.  If that
+ * file has been stripped from your copy of libpng, you can find it at
+ * <http://www.libpng.org/pub/png/libpng-manual.txt>
+ *
+ * If you just need to read a PNG file and don't want to read the documentation
+ * skip to the end of this file and read the section entitled 'simplified API'.
+ */
+
+/* Version information for png.h - this should match the version in png.c */
+#define PNG_LIBPNG_VER_STRING "1.6.43"
+#define PNG_HEADER_VERSION_STRING " libpng version " PNG_LIBPNG_VER_STRING "\n"
+
+/* The versions of shared library builds should stay in sync, going forward */
+#define PNG_LIBPNG_VER_SHAREDLIB 16
+#define PNG_LIBPNG_VER_SONUM     PNG_LIBPNG_VER_SHAREDLIB /* [Deprecated] */
+#define PNG_LIBPNG_VER_DLLNUM    PNG_LIBPNG_VER_SHAREDLIB /* [Deprecated] */
+
+/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
+#define PNG_LIBPNG_VER_MAJOR   1
+#define PNG_LIBPNG_VER_MINOR   6
+#define PNG_LIBPNG_VER_RELEASE 43
+
+/* This should be zero for a public release, or non-zero for a
+ * development version.
+ */
+#define PNG_LIBPNG_VER_BUILD  0
+
+/* Release Status */
+#define PNG_LIBPNG_BUILD_ALPHA    1
+#define PNG_LIBPNG_BUILD_BETA     2
+#define PNG_LIBPNG_BUILD_RC       3
+#define PNG_LIBPNG_BUILD_STABLE   4
+#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
+
+/* Release-Specific Flags */
+#define PNG_LIBPNG_BUILD_PATCH    8 /* Can be OR'ed with
+                                       PNG_LIBPNG_BUILD_STABLE only */
+#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
+                                       PNG_LIBPNG_BUILD_SPECIAL */
+#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
+                                       PNG_LIBPNG_BUILD_PRIVATE */
+
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
+
+/* Careful here.  At one time, Guy wanted to use 082, but that
+ * would be octal.  We must not include leading zeros.
+ * Versions 0.7 through 1.0.0 were in the range 0 to 100 here
+ * (only version 1.0.0 was mis-numbered 100 instead of 10000).
+ * From version 1.0.1 it is:
+ * XXYYZZ, where XX=major, YY=minor, ZZ=release
+ */
+#define PNG_LIBPNG_VER 10643 /* 1.6.43 */
+
+/* Library configuration: these options cannot be changed after
+ * the library has been built.
+ */
+#ifndef PNGLCONF_H
+/* If pnglibconf.h is missing, you can
+ * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
+ */
+#   include "pnglibconf.h"
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+/* Machine specific configuration. */
+#  include "pngconf.h"
+#endif
+
+/*
+ * Added at libpng-1.2.8
+ *
+ * Ref MSDN: Private as priority over Special
+ * VS_FF_PRIVATEBUILD File *was not* built using standard release
+ * procedures. If this value is given, the StringFileInfo block must
+ * contain a PrivateBuild string.
+ *
+ * VS_FF_SPECIALBUILD File *was* built by the original company using
+ * standard release procedures but is a variation of the standard
+ * file of the same version number. If this value is given, the
+ * StringFileInfo block must contain a SpecialBuild string.
+ */
+
+#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
+#  define PNG_LIBPNG_BUILD_TYPE \
+       (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
+#else
+#  ifdef PNG_LIBPNG_SPECIALBUILD
+#    define PNG_LIBPNG_BUILD_TYPE \
+         (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
+#  else
+#    define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
+#  endif
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+
+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* Version information for C files, stored in png.c.  This had better match
+ * the version above.
+ */
+#define png_libpng_ver png_get_header_ver(NULL)
+
+/* This file is arranged in several sections:
+ *
+ * 1. [omitted]
+ * 2. Any configuration options that can be specified by for the application
+ *    code when it is built.  (Build time configuration is in pnglibconf.h)
+ * 3. Type definitions (base types are defined in pngconf.h), structure
+ *    definitions.
+ * 4. Exported library functions.
+ * 5. Simplified API.
+ * 6. Implementation options.
+ *
+ * The library source code has additional files (principally pngpriv.h) that
+ * allow configuration of the library.
+ */
+
+/* Section 1: [omitted] */
+
+/* Section 2: run time configuration
+ * See pnglibconf.h for build time configuration
+ *
+ * Run time configuration allows the application to choose between
+ * implementations of certain arithmetic APIs.  The default is set
+ * at build time and recorded in pnglibconf.h, but it is safe to
+ * override these (and only these) settings.  Note that this won't
+ * change what the library does, only application code, and the
+ * settings can (and probably should) be made on a per-file basis
+ * by setting the #defines before including png.h
+ *
+ * Use macros to read integers from PNG data or use the exported
+ * functions?
+ *   PNG_USE_READ_MACROS: use the macros (see below)  Note that
+ *     the macros evaluate their argument multiple times.
+ *   PNG_NO_USE_READ_MACROS: call the relevant library function.
+ *
+ * Use the alternative algorithm for compositing alpha samples that
+ * does not use division?
+ *   PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
+ *      algorithm.
+ *   PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
+ *
+ * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
+ * false?
+ *   PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
+ *      APIs to png_warning.
+ * Otherwise the calls are mapped to png_error.
+ */
+
+/* Section 3: type definitions, including structures and compile time
+ * constants.
+ * See pngconf.h for base types that vary by machine/system
+ */
+
+/* This triggers a compiler error in png.c, if png.c and png.h
+ * do not agree upon the version number.
+ */
+typedef char* png_libpng_version_1_6_43;
+
+/* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
+ *
+ * png_struct is the cache of information used while reading or writing a single
+ * PNG file.  One of these is always required, although the simplified API
+ * (below) hides the creation and destruction of it.
+ */
+typedef struct png_struct_def png_struct;
+typedef const png_struct * png_const_structp;
+typedef png_struct * png_structp;
+typedef png_struct * * png_structpp;
+
+/* png_info contains information read from or to be written to a PNG file.  One
+ * or more of these must exist while reading or creating a PNG file.  The
+ * information is not used by libpng during read but is used to control what
+ * gets written when a PNG file is created.  "png_get_" function calls read
+ * information during read and "png_set_" functions calls write information
+ * when creating a PNG.
+ * been moved into a separate header file that is not accessible to
+ * applications.  Read libpng-manual.txt or libpng.3 for more info.
+ */
+typedef struct png_info_def png_info;
+typedef png_info * png_infop;
+typedef const png_info * png_const_infop;
+typedef png_info * * png_infopp;
+
+/* Types with names ending 'p' are pointer types.  The corresponding types with
+ * names ending 'rp' are identical pointer types except that the pointer is
+ * marked 'restrict', which means that it is the only pointer to the object
+ * passed to the function.  Applications should not use the 'restrict' types;
+ * it is always valid to pass 'p' to a pointer with a function argument of the
+ * corresponding 'rp' type.  Different compilers have different rules with
+ * regard to type matching in the presence of 'restrict'.  For backward
+ * compatibility libpng callbacks never have 'restrict' in their parameters and,
+ * consequentially, writing portable application code is extremely difficult if
+ * an attempt is made to use 'restrict'.
+ */
+typedef png_struct * PNG_RESTRICT png_structrp;
+typedef const png_struct * PNG_RESTRICT png_const_structrp;
+typedef png_info * PNG_RESTRICT png_inforp;
+typedef const png_info * PNG_RESTRICT png_const_inforp;
+
+/* Three color definitions.  The order of the red, green, and blue, (and the
+ * exact size) is not important, although the size of the fields need to
+ * be png_byte or png_uint_16 (as defined below).
+ */
+typedef struct png_color_struct
+{
+   png_byte red;
+   png_byte green;
+   png_byte blue;
+} png_color;
+typedef png_color * png_colorp;
+typedef const png_color * png_const_colorp;
+typedef png_color * * png_colorpp;
+
+typedef struct png_color_16_struct
+{
+   png_byte index;    /* used for palette files */
+   png_uint_16 red;   /* for use in red green blue files */
+   png_uint_16 green;
+   png_uint_16 blue;
+   png_uint_16 gray;  /* for use in grayscale files */
+} png_color_16;
+typedef png_color_16 * png_color_16p;
+typedef const png_color_16 * png_const_color_16p;
+typedef png_color_16 * * png_color_16pp;
+
+typedef struct png_color_8_struct
+{
+   png_byte red;   /* for use in red green blue files */
+   png_byte green;
+   png_byte blue;
+   png_byte gray;  /* for use in grayscale files */
+   png_byte alpha; /* for alpha channel files */
+} png_color_8;
+typedef png_color_8 * png_color_8p;
+typedef const png_color_8 * png_const_color_8p;
+typedef png_color_8 * * png_color_8pp;
+
+/*
+ * The following two structures are used for the in-core representation
+ * of sPLT chunks.
+ */
+typedef struct png_sPLT_entry_struct
+{
+   png_uint_16 red;
+   png_uint_16 green;
+   png_uint_16 blue;
+   png_uint_16 alpha;
+   png_uint_16 frequency;
+} png_sPLT_entry;
+typedef png_sPLT_entry * png_sPLT_entryp;
+typedef const png_sPLT_entry * png_const_sPLT_entryp;
+typedef png_sPLT_entry * * png_sPLT_entrypp;
+
+/*  When the depth of the sPLT palette is 8 bits, the color and alpha samples
+ *  occupy the LSB of their respective members, and the MSB of each member
+ *  is zero-filled.  The frequency member always occupies the full 16 bits.
+ */
+
+typedef struct png_sPLT_struct
+{
+   png_charp name;           /* palette name */
+   png_byte depth;           /* depth of palette samples */
+   png_sPLT_entryp entries;  /* palette entries */
+   png_int_32 nentries;      /* number of palette entries */
+} png_sPLT_t;
+typedef png_sPLT_t * png_sPLT_tp;
+typedef const png_sPLT_t * png_const_sPLT_tp;
+typedef png_sPLT_t * * png_sPLT_tpp;
+
+#ifdef PNG_TEXT_SUPPORTED
+/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
+ * and whether that contents is compressed or not.  The "key" field
+ * points to a regular zero-terminated C string.  The "text" fields can be a
+ * regular C string, an empty string, or a NULL pointer.
+ * However, the structure returned by png_get_text() will always contain
+ * the "text" field as a regular zero-terminated C string (possibly
+ * empty), never a NULL pointer, so it can be safely used in printf() and
+ * other string-handling functions.  Note that the "itxt_length", "lang", and
+ * "lang_key" members of the structure only exist when the library is built
+ * with iTXt chunk support.  Prior to libpng-1.4.0 the library was built by
+ * default without iTXt support. Also note that when iTXt *is* supported,
+ * the "lang" and "lang_key" fields contain NULL pointers when the
+ * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
+ * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
+ * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
+ * which is always 0 or 1, or its "compression method" which is always 0.
+ */
+typedef struct png_text_struct
+{
+   int  compression;       /* compression value:
+                             -1: tEXt, none
+                              0: zTXt, deflate
+                              1: iTXt, none
+                              2: iTXt, deflate  */
+   png_charp key;          /* keyword, 1-79 character description of "text" */
+   png_charp text;         /* comment, may be an empty string (ie "")
+                              or a NULL pointer */
+   size_t text_length;     /* length of the text string */
+   size_t itxt_length;     /* length of the itxt string */
+   png_charp lang;         /* language code, 0-79 characters
+                              or a NULL pointer */
+   png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
+                              chars or a NULL pointer */
+} png_text;
+typedef png_text * png_textp;
+typedef const png_text * png_const_textp;
+typedef png_text * * png_textpp;
+#endif
+
+/* Supported compression types for text in PNG files (tEXt, and zTXt).
+ * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
+#define PNG_TEXT_COMPRESSION_NONE_WR -3
+#define PNG_TEXT_COMPRESSION_zTXt_WR -2
+#define PNG_TEXT_COMPRESSION_NONE    -1
+#define PNG_TEXT_COMPRESSION_zTXt     0
+#define PNG_ITXT_COMPRESSION_NONE     1
+#define PNG_ITXT_COMPRESSION_zTXt     2
+#define PNG_TEXT_COMPRESSION_LAST     3  /* Not a valid value */
+
+/* png_time is a way to hold the time in an machine independent way.
+ * Two conversions are provided, both from time_t and struct tm.  There
+ * is no portable way to convert to either of these structures, as far
+ * as I know.  If you know of a portable way, send it to me.  As a side
+ * note - PNG has always been Year 2000 compliant!
+ */
+typedef struct png_time_struct
+{
+   png_uint_16 year; /* full year, as in, 1995 */
+   png_byte month;   /* month of year, 1 - 12 */
+   png_byte day;     /* day of month, 1 - 31 */
+   png_byte hour;    /* hour of day, 0 - 23 */
+   png_byte minute;  /* minute of hour, 0 - 59 */
+   png_byte second;  /* second of minute, 0 - 60 (for leap seconds) */
+} png_time;
+typedef png_time * png_timep;
+typedef const png_time * png_const_timep;
+typedef png_time * * png_timepp;
+
+#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
+   defined(PNG_USER_CHUNKS_SUPPORTED)
+/* png_unknown_chunk is a structure to hold queued chunks for which there is
+ * no specific support.  The idea is that we can use this to queue
+ * up private chunks for output even though the library doesn't actually
+ * know about their semantics.
+ *
+ * The data in the structure is set by libpng on read and used on write.
+ */
+typedef struct png_unknown_chunk_t
+{
+   png_byte name[5]; /* Textual chunk name with '\0' terminator */
+   png_byte *data;   /* Data, should not be modified on read! */
+   size_t size;
+
+   /* On write 'location' must be set using the flag values listed below.
+    * Notice that on read it is set by libpng however the values stored have
+    * more bits set than are listed below.  Always treat the value as a
+    * bitmask.  On write set only one bit - setting multiple bits may cause the
+    * chunk to be written in multiple places.
+    */
+   png_byte location; /* mode of operation at read time */
+}
+png_unknown_chunk;
+
+typedef png_unknown_chunk * png_unknown_chunkp;
+typedef const png_unknown_chunk * png_const_unknown_chunkp;
+typedef png_unknown_chunk * * png_unknown_chunkpp;
+#endif
+
+/* Flag values for the unknown chunk location byte. */
+#define PNG_HAVE_IHDR  0x01
+#define PNG_HAVE_PLTE  0x02
+#define PNG_AFTER_IDAT 0x08
+
+/* Maximum positive integer used in PNG is (2^31)-1 */
+#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
+#define PNG_UINT_32_MAX ((png_uint_32)(-1))
+#define PNG_SIZE_MAX ((size_t)(-1))
+
+/* These are constants for fixed point values encoded in the
+ * PNG specification manner (x100000)
+ */
+#define PNG_FP_1    100000
+#define PNG_FP_HALF  50000
+#define PNG_FP_MAX  ((png_fixed_point)0x7fffffffL)
+#define PNG_FP_MIN  (-PNG_FP_MAX)
+
+/* These describe the color_type field in png_info. */
+/* color type masks */
+#define PNG_COLOR_MASK_PALETTE    1
+#define PNG_COLOR_MASK_COLOR      2
+#define PNG_COLOR_MASK_ALPHA      4
+
+/* color types.  Note that not all combinations are legal */
+#define PNG_COLOR_TYPE_GRAY 0
+#define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
+#define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
+#define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
+#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
+/* aliases */
+#define PNG_COLOR_TYPE_RGBA  PNG_COLOR_TYPE_RGB_ALPHA
+#define PNG_COLOR_TYPE_GA  PNG_COLOR_TYPE_GRAY_ALPHA
+
+/* This is for compression type. PNG 1.0-1.2 only define the single type. */
+#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
+#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
+
+/* This is for filter type. PNG 1.0-1.2 only define the single type. */
+#define PNG_FILTER_TYPE_BASE      0 /* Single row per-byte filtering */
+#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
+#define PNG_FILTER_TYPE_DEFAULT   PNG_FILTER_TYPE_BASE
+
+/* These are for the interlacing type.  These values should NOT be changed. */
+#define PNG_INTERLACE_NONE        0 /* Non-interlaced image */
+#define PNG_INTERLACE_ADAM7       1 /* Adam7 interlacing */
+#define PNG_INTERLACE_LAST        2 /* Not a valid value */
+
+/* These are for the oFFs chunk.  These values should NOT be changed. */
+#define PNG_OFFSET_PIXEL          0 /* Offset in pixels */
+#define PNG_OFFSET_MICROMETER     1 /* Offset in micrometers (1/10^6 meter) */
+#define PNG_OFFSET_LAST           2 /* Not a valid value */
+
+/* These are for the pCAL chunk.  These values should NOT be changed. */
+#define PNG_EQUATION_LINEAR       0 /* Linear transformation */
+#define PNG_EQUATION_BASE_E       1 /* Exponential base e transform */
+#define PNG_EQUATION_ARBITRARY    2 /* Arbitrary base exponential transform */
+#define PNG_EQUATION_HYPERBOLIC   3 /* Hyperbolic sine transformation */
+#define PNG_EQUATION_LAST         4 /* Not a valid value */
+
+/* These are for the sCAL chunk.  These values should NOT be changed. */
+#define PNG_SCALE_UNKNOWN         0 /* unknown unit (image scale) */
+#define PNG_SCALE_METER           1 /* meters per pixel */
+#define PNG_SCALE_RADIAN          2 /* radians per pixel */
+#define PNG_SCALE_LAST            3 /* Not a valid value */
+
+/* These are for the pHYs chunk.  These values should NOT be changed. */
+#define PNG_RESOLUTION_UNKNOWN    0 /* pixels/unknown unit (aspect ratio) */
+#define PNG_RESOLUTION_METER      1 /* pixels/meter */
+#define PNG_RESOLUTION_LAST       2 /* Not a valid value */
+
+/* These are for the sRGB chunk.  These values should NOT be changed. */
+#define PNG_sRGB_INTENT_PERCEPTUAL 0
+#define PNG_sRGB_INTENT_RELATIVE   1
+#define PNG_sRGB_INTENT_SATURATION 2
+#define PNG_sRGB_INTENT_ABSOLUTE   3
+#define PNG_sRGB_INTENT_LAST       4 /* Not a valid value */
+
+/* This is for text chunks */
+#define PNG_KEYWORD_MAX_LENGTH     79
+
+/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
+#define PNG_MAX_PALETTE_LENGTH    256
+
+/* These determine if an ancillary chunk's data has been successfully read
+ * from the PNG header, or if the application has filled in the corresponding
+ * data in the info_struct to be written into the output file.  The values
+ * of the PNG_INFO_<chunk> defines should NOT be changed.
+ */
+#define PNG_INFO_gAMA 0x0001U
+#define PNG_INFO_sBIT 0x0002U
+#define PNG_INFO_cHRM 0x0004U
+#define PNG_INFO_PLTE 0x0008U
+#define PNG_INFO_tRNS 0x0010U
+#define PNG_INFO_bKGD 0x0020U
+#define PNG_INFO_hIST 0x0040U
+#define PNG_INFO_pHYs 0x0080U
+#define PNG_INFO_oFFs 0x0100U
+#define PNG_INFO_tIME 0x0200U
+#define PNG_INFO_pCAL 0x0400U
+#define PNG_INFO_sRGB 0x0800U  /* GR-P, 0.96a */
+#define PNG_INFO_iCCP 0x1000U  /* ESR, 1.0.6 */
+#define PNG_INFO_sPLT 0x2000U  /* ESR, 1.0.6 */
+#define PNG_INFO_sCAL 0x4000U  /* ESR, 1.0.6 */
+#define PNG_INFO_IDAT 0x8000U  /* ESR, 1.0.6 */
+#define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */
+
+/* This is used for the transformation routines, as some of them
+ * change these values for the row.  It also should enable using
+ * the routines for other purposes.
+ */
+typedef struct png_row_info_struct
+{
+   png_uint_32 width;    /* width of row */
+   size_t rowbytes;      /* number of bytes in row */
+   png_byte color_type;  /* color type of row */
+   png_byte bit_depth;   /* bit depth of row */
+   png_byte channels;    /* number of channels (1, 2, 3, or 4) */
+   png_byte pixel_depth; /* bits per pixel (depth * channels) */
+} png_row_info;
+
+typedef png_row_info * png_row_infop;
+typedef png_row_info * * png_row_infopp;
+
+/* These are the function types for the I/O functions and for the functions
+ * that allow the user to override the default I/O functions with his or her
+ * own.  The png_error_ptr type should match that of user-supplied warning
+ * and error functions, while the png_rw_ptr type should match that of the
+ * user read/write data functions.  Note that the 'write' function must not
+ * modify the buffer it is passed. The 'read' function, on the other hand, is
+ * expected to return the read data in the buffer.
+ */
+typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
+typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
+typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
+typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
+    int));
+typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
+    int));
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
+typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
+
+/* The following callback receives png_uint_32 row_number, int pass for the
+ * png_bytep data of the row.  When transforming an interlaced image the
+ * row number is the row number within the sub-image of the interlace pass, so
+ * the value will increase to the height of the sub-image (not the full image)
+ * then reset to 0 for the next pass.
+ *
+ * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+ * find the output pixel (x,y) given an interlaced sub-image pixel
+ * (row,col,pass).  (See below for these macros.)
+ */
+typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
+    png_uint_32, int));
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
+    png_bytep));
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
+    png_unknown_chunkp));
+#endif
+#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
+/* not used anywhere */
+/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+/* This must match the function definition in <setjmp.h>, and the application
+ * must include this before png.h to obtain the definition of jmp_buf.  The
+ * function is required to be PNG_NORETURN, but this is not checked.  If the
+ * function does return the application will crash via an abort() or similar
+ * system level call.
+ *
+ * If you get a warning here while building the library you may need to make
+ * changes to ensure that pnglibconf.h records the calling convention used by
+ * your compiler.  This may be very difficult - try using a different compiler
+ * to build the library!
+ */
+PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
+#endif
+
+/* Transform masks for the high-level interface */
+#define PNG_TRANSFORM_IDENTITY       0x0000    /* read and write */
+#define PNG_TRANSFORM_STRIP_16       0x0001    /* read only */
+#define PNG_TRANSFORM_STRIP_ALPHA    0x0002    /* read only */
+#define PNG_TRANSFORM_PACKING        0x0004    /* read and write */
+#define PNG_TRANSFORM_PACKSWAP       0x0008    /* read and write */
+#define PNG_TRANSFORM_EXPAND         0x0010    /* read only */
+#define PNG_TRANSFORM_INVERT_MONO    0x0020    /* read and write */
+#define PNG_TRANSFORM_SHIFT          0x0040    /* read and write */
+#define PNG_TRANSFORM_BGR            0x0080    /* read and write */
+#define PNG_TRANSFORM_SWAP_ALPHA     0x0100    /* read and write */
+#define PNG_TRANSFORM_SWAP_ENDIAN    0x0200    /* read and write */
+#define PNG_TRANSFORM_INVERT_ALPHA   0x0400    /* read and write */
+#define PNG_TRANSFORM_STRIP_FILLER   0x0800    /* write only */
+/* Added to libpng-1.2.34 */
+#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
+#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
+/* Added to libpng-1.4.0 */
+#define PNG_TRANSFORM_GRAY_TO_RGB   0x2000      /* read only */
+/* Added to libpng-1.5.4 */
+#define PNG_TRANSFORM_EXPAND_16     0x4000      /* read only */
+#if ~0U > 0xffffU /* or else this might break on a 16-bit machine */
+#define PNG_TRANSFORM_SCALE_16      0x8000      /* read only */
+#endif
+
+/* Flags for MNG supported features */
+#define PNG_FLAG_MNG_EMPTY_PLTE     0x01
+#define PNG_FLAG_MNG_FILTER_64      0x04
+#define PNG_ALL_MNG_FEATURES        0x05
+
+/* NOTE: prior to 1.5 these functions had no 'API' style declaration,
+ * this allowed the zlib default functions to be used on Windows
+ * platforms.  In 1.5 the zlib default malloc (which just calls malloc and
+ * ignores the first argument) should be completely compatible with the
+ * following.
+ */
+typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
+    png_alloc_size_t));
+typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
+
+/* Section 4: exported functions
+ * Here are the function definitions most commonly used.  This is not
+ * the place to find out how to use libpng.  See libpng-manual.txt for the
+ * full explanation, see example.c for the summary.  This just provides
+ * a simple one line description of the use of each function.
+ *
+ * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
+ * pngconf.h and in the *.dfn files in the scripts directory.
+ *
+ *   PNG_EXPORT(ordinal, type, name, (args));
+ *
+ *       ordinal:    ordinal that is used while building
+ *                   *.def files. The ordinal value is only
+ *                   relevant when preprocessing png.h with
+ *                   the *.dfn files for building symbol table
+ *                   entries, and are removed by pngconf.h.
+ *       type:       return type of the function
+ *       name:       function name
+ *       args:       function arguments, with types
+ *
+ * When we wish to append attributes to a function prototype we use
+ * the PNG_EXPORTA() macro instead.
+ *
+ *   PNG_EXPORTA(ordinal, type, name, (args), attributes);
+ *
+ *       ordinal, type, name, and args: same as in PNG_EXPORT().
+ *       attributes: function attributes
+ */
+
+/* Returns the version number of the library */
+PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
+
+/* Tell lib we have already handled the first <num_bytes> magic bytes.
+ * Handling more than 8 bytes from the beginning of the file is an error.
+ */
+PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
+
+/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
+ * PNG file.  Returns zero if the supplied bytes match the 8-byte PNG
+ * signature, and non-zero otherwise.  Having num_to_check == 0 or
+ * start > 7 will always fail (i.e. return non-zero).
+ */
+PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start,
+    size_t num_to_check));
+
+/* Simple signature checking function.  This is the same as calling
+ * png_check_sig(sig, n) := (png_sig_cmp(sig, 0, n) == 0).
+ */
+#define png_check_sig(sig, n) (png_sig_cmp((sig), 0, (n)) == 0) /* DEPRECATED */
+
+/* Allocate and initialize png_ptr struct for reading, and any other memory. */
+PNG_EXPORTA(4, png_structp, png_create_read_struct,
+    (png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn),
+    PNG_ALLOCATED);
+
+/* Allocate and initialize png_ptr struct for writing, and any other memory */
+PNG_EXPORTA(5, png_structp, png_create_write_struct,
+    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+    png_error_ptr warn_fn),
+    PNG_ALLOCATED);
+
+PNG_EXPORT(6, size_t, png_get_compression_buffer_size,
+    (png_const_structrp png_ptr));
+
+PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
+    size_t size));
+
+/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
+ * match up.
+ */
+#ifdef PNG_SETJMP_SUPPORTED
+/* This function returns the jmp_buf built in to *png_ptr.  It must be
+ * supplied with an appropriate 'longjmp' function to use on that jmp_buf
+ * unless the default error function is overridden in which case NULL is
+ * acceptable.  The size of the jmp_buf is checked against the actual size
+ * allocated by the library - the call will return NULL on a mismatch
+ * indicating an ABI mismatch.
+ */
+PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
+    png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
+#  define png_jmpbuf(png_ptr) \
+      (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
+#else
+#  define png_jmpbuf(png_ptr) \
+      (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
+#endif
+/* This function should be used by libpng applications in place of
+ * longjmp(png_ptr->jmpbuf, val).  If longjmp_fn() has been set, it
+ * will use it; otherwise it will call PNG_ABORT().  This function was
+ * added in libpng-1.5.0.
+ */
+PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
+    PNG_NORETURN);
+
+#ifdef PNG_READ_SUPPORTED
+/* Reset the compression stream */
+PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
+#endif
+
+/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
+    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+    png_error_ptr warn_fn,
+    png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
+    PNG_ALLOCATED);
+PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
+    (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+    png_error_ptr warn_fn,
+    png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
+    PNG_ALLOCATED);
+#endif
+
+/* Write the PNG file signature. */
+PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
+
+/* Write a PNG chunk - size, type, (optional) data, CRC. */
+PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
+    chunk_name, png_const_bytep data, size_t length));
+
+/* Write the start of a PNG chunk - length and chunk name. */
+PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
+    png_const_bytep chunk_name, png_uint_32 length));
+
+/* Write the data of a PNG chunk started with png_write_chunk_start(). */
+PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
+    png_const_bytep data, size_t length));
+
+/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
+PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
+
+/* Allocate and initialize the info structure */
+PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
+    PNG_ALLOCATED);
+
+/* DEPRECATED: this function allowed init structures to be created using the
+ * default allocation method (typically malloc).  Use is deprecated in 1.6.0 and
+ * the API will be removed in the future.
+ */
+PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
+    size_t png_info_struct_size), PNG_DEPRECATED);
+
+/* Writes all the PNG information before the image. */
+PNG_EXPORT(20, void, png_write_info_before_PLTE,
+    (png_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(21, void, png_write_info,
+    (png_structrp png_ptr, png_const_inforp info_ptr));
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the information before the actual image data. */
+PNG_EXPORT(22, void, png_read_info,
+    (png_structrp png_ptr, png_inforp info_ptr));
+#endif
+
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+   /* Convert to a US string format: there is no localization support in this
+    * routine.  The original implementation used a 29 character buffer in
+    * png_struct, this will be removed in future versions.
+    */
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
+PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
+    png_const_timep ptime),PNG_DEPRECATED);
+#endif
+PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
+    png_const_timep ptime));
+#endif
+
+#ifdef PNG_CONVERT_tIME_SUPPORTED
+/* Convert from a struct tm to png_time */
+PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
+    const struct tm * ttime));
+
+/* Convert from time_t to png_time.  Uses gmtime() */
+PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
+#endif /* CONVERT_tIME */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
+PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
+PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
+PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
+PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
+ * of a tRNS chunk if present.
+ */
+PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Use blue, green, red order for pixels. */
+PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* Expand the grayscale to 24-bit RGB if necessary. */
+PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* Reduce RGB to grayscale. */
+#define PNG_ERROR_ACTION_NONE  1
+#define PNG_ERROR_ACTION_WARN  2
+#define PNG_ERROR_ACTION_ERROR 3
+#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
+
+PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
+    int error_action, double red, double green))
+PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
+    int error_action, png_fixed_point red, png_fixed_point green))
+
+PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
+    png_ptr));
+#endif
+
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
+    png_colorp palette));
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* How the alpha channel is interpreted - this affects how the color channels
+ * of a PNG file are returned to the calling application when an alpha channel,
+ * or a tRNS chunk in a palette file, is present.
+ *
+ * This has no effect on the way pixels are written into a PNG output
+ * datastream. The color samples in a PNG datastream are never premultiplied
+ * with the alpha samples.
+ *
+ * The default is to return data according to the PNG specification: the alpha
+ * channel is a linear measure of the contribution of the pixel to the
+ * corresponding composited pixel, and the color channels are unassociated
+ * (not premultiplied).  The gamma encoded color channels must be scaled
+ * according to the contribution and to do this it is necessary to undo
+ * the encoding, scale the color values, perform the composition and re-encode
+ * the values.  This is the 'PNG' mode.
+ *
+ * The alternative is to 'associate' the alpha with the color information by
+ * storing color channel values that have been scaled by the alpha.
+ * image.  These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+ * (the latter being the two common names for associated alpha color channels).
+ *
+ * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
+ * value is equal to the maximum value.
+ *
+ * The final choice is to gamma encode the alpha channel as well.  This is
+ * broken because, in practice, no implementation that uses this choice
+ * correctly undoes the encoding before handling alpha composition.  Use this
+ * choice only if other serious errors in the software or hardware you use
+ * mandate it; the typical serious error is for dark halos to appear around
+ * opaque areas of the composited PNG image because of arithmetic overflow.
+ *
+ * The API function png_set_alpha_mode specifies which of these choices to use
+ * with an enumerated 'mode' value and the gamma of the required output:
+ */
+#define PNG_ALPHA_PNG           0 /* according to the PNG standard */
+#define PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
+#define PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
+#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
+#define PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
+#define PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
+
+PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
+    double output_gamma))
+PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
+    int mode, png_fixed_point output_gamma))
+#endif
+
+#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+/* The output_gamma value is a screen gamma in libpng terminology: it expresses
+ * how to decode the output values, not how they are encoded.
+ */
+#define PNG_DEFAULT_sRGB -1       /* sRGB gamma and color space */
+#define PNG_GAMMA_MAC_18 -2       /* Old Mac '1.8' gamma and color space */
+#define PNG_GAMMA_sRGB   220000   /* Television standards--matches sRGB gamma */
+#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
+#endif
+
+/* The following are examples of calls to png_set_alpha_mode to achieve the
+ * required overall gamma correction and, where necessary, alpha
+ * premultiplication.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ *    This is the default libpng handling of the alpha channel - it is not
+ *    pre-multiplied into the color components.  In addition the call states
+ *    that the output is for a sRGB system and causes all PNG files without gAMA
+ *    chunks to be assumed to be encoded using sRGB.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ *    In this case the output is assumed to be something like an sRGB conformant
+ *    display preceded by a power-law lookup table of power 1.45.  This is how
+ *    early Mac systems behaved.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+ *    This is the classic Jim Blinn approach and will work in academic
+ *    environments where everything is done by the book.  It has the shortcoming
+ *    of assuming that input PNG data with no gamma information is linear - this
+ *    is unlikely to be correct unless the PNG files where generated locally.
+ *    Most of the time the output precision will be so low as to show
+ *    significant banding in dark areas of the image.
+ *
+ * png_set_expand_16(pp);
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+ *    This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
+ *    are assumed to have the sRGB encoding if not marked with a gamma value and
+ *    the output is always 16 bits per component.  This permits accurate scaling
+ *    and processing of the data.  If you know that your input PNG files were
+ *    generated locally you might need to replace PNG_DEFAULT_sRGB with the
+ *    correct value for your system.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+ *    If you just need to composite the PNG image onto an existing background
+ *    and if you control the code that does this you can use the optimization
+ *    setting.  In this case you just copy completely opaque pixels to the
+ *    output.  For pixels that are not completely transparent (you just skip
+ *    those) you do the composition math using png_composite or png_composite_16
+ *    below then encode the resultant 8-bit or 16-bit values to match the output
+ *    encoding.
+ *
+ * Other cases
+ *    If neither the PNG nor the standard linear encoding work for you because
+ *    of the software or hardware you use then you have a big problem.  The PNG
+ *    case will probably result in halos around the image.  The linear encoding
+ *    will probably result in a washed out, too bright, image (it's actually too
+ *    contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
+ *    substantially reduce the halos.  Alternatively try:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+ *    This option will also reduce the halos, but there will be slight dark
+ *    halos round the opaque parts of the image where the background is light.
+ *    In the OPTIMIZED mode the halos will be light halos where the background
+ *    is dark.  Take your pick - the halos are unavoidable unless you can get
+ *    your hardware/software fixed!  (The OPTIMIZED approach is slightly
+ *    faster.)
+ *
+ * When the default gamma of PNG files doesn't match the output gamma.
+ *    If you have PNG files with no gamma information png_set_alpha_mode allows
+ *    you to provide a default gamma, but it also sets the output gamma to the
+ *    matching value.  If you know your PNG files have a gamma that doesn't
+ *    match the output you can take advantage of the fact that
+ *    png_set_alpha_mode always sets the output gamma but only sets the PNG
+ *    default if it is not already set:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ *    The first call sets both the default and the output gamma values, the
+ *    second call overrides the output gamma without changing the default.  This
+ *    is easier than achieving the same effect with png_set_gamma.  You must use
+ *    PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+ *    fire if more than one call to png_set_alpha_mode and png_set_background is
+ *    made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+ *    are ignored.
+ */
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+/* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
+PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
+    int flags));
+/* The values of the PNG_FILLER_ defines should NOT be changed */
+#  define PNG_FILLER_BEFORE 0
+#  define PNG_FILLER_AFTER 1
+/* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
+PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
+    png_uint_32 filler, int flags));
+#endif /* READ_FILLER || WRITE_FILLER */
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Swap bytes in 16-bit depth files. */
+PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
+PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
+    defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+/* Swap packing order of pixels in bytes. */
+PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+/* Converts files to legal bit depths. */
+PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
+    true_bits));
+#endif
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+    defined(PNG_WRITE_INTERLACING_SUPPORTED)
+/* Have the code handle the interlacing.  Returns the number of passes.
+ * MUST be called before png_read_update_info or png_start_read_image,
+ * otherwise it will not have the desired effect.  Note that it is still
+ * necessary to call png_read_row or png_read_rows png_get_image_height
+ * times for each pass.
+*/
+PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+/* Invert monochrome files */
+PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* Handle alpha and tRNS by replacing with a background color.  Prior to
+ * libpng-1.5.4 this API must not be called before the PNG file header has been
+ * read.  Doing so will result in unexpected behavior and possible warnings or
+ * errors if the PNG file contains a bKGD chunk.
+ */
+PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
+    png_const_color_16p background_color, int background_gamma_code,
+    int need_expand, double background_gamma))
+PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
+    png_const_color_16p background_color, int background_gamma_code,
+    int need_expand, png_fixed_point background_gamma))
+#endif
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+#  define PNG_BACKGROUND_GAMMA_UNKNOWN 0
+#  define PNG_BACKGROUND_GAMMA_SCREEN  1
+#  define PNG_BACKGROUND_GAMMA_FILE    2
+#  define PNG_BACKGROUND_GAMMA_UNIQUE  3
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+/* Scale a 16-bit depth file down to 8-bit, accurately. */
+PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+#define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */
+/* Strip the second byte of information from a 16-bit depth file. */
+PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* Turn on quantizing, and reduce the palette to the number of colors
+ * available.
+ */
+PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
+    png_colorp palette, int num_palette, int maximum_colors,
+    png_const_uint_16p histogram, int full_quantize));
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* The threshold on gamma processing is configurable but hard-wired into the
+ * library.  The following is the floating point variant.
+ */
+#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
+
+/* Handle gamma correction. Screen_gamma=(display_exponent).
+ * NOTE: this API simply sets the screen and file gamma values. It will
+ * therefore override the value for gamma in a PNG file if it is called after
+ * the file header has been read - use with care  - call before reading the PNG
+ * file for best results!
+ *
+ * These routines accept the same gamma values as png_set_alpha_mode (described
+ * above).  The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
+ * API (floating point or fixed.)  Notice, however, that the 'file_gamma' value
+ * is the inverse of a 'screen gamma' value.
+ */
+PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
+    double screen_gamma, double override_file_gamma))
+PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
+    png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
+#endif
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+/* Set how many lines between output flushes - 0 for no flushing */
+PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
+/* Flush the current PNG output buffer */
+PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
+#endif
+
+/* Optional update palette with requested transformations */
+PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
+
+/* Optional call to update the users info structure */
+PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
+    png_inforp info_ptr));
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read one or more rows of image data. */
+PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
+    png_bytepp display_row, png_uint_32 num_rows));
+#endif
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read a row of data. */
+PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
+    png_bytep display_row));
+#endif
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the whole image into memory at once. */
+PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
+#endif
+
+/* Write a row of image data */
+PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
+    png_const_bytep row));
+
+/* Write a few rows of image data: (*row) is not written; however, the type
+ * is declared as writeable to maintain compatibility with previous versions
+ * of libpng and to allow the 'display_row' array from read_rows to be passed
+ * unchanged to write_rows.
+ */
+PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
+    png_uint_32 num_rows));
+
+/* Write the image data */
+PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
+
+/* Write the end of the PNG file. */
+PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
+    png_inforp info_ptr));
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the end of the PNG file. */
+PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
+#endif
+
+/* Free any memory associated with the png_info_struct */
+PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
+    png_infopp info_ptr_ptr));
+
+/* Free any memory associated with the png_struct and the png_info_structs */
+PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
+    png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
+
+/* Free any memory associated with the png_struct and the png_info_structs */
+PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
+    png_infopp info_ptr_ptr));
+
+/* Set the libpng method of handling chunk CRC errors */
+PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
+    int ancil_action));
+
+/* Values for png_set_crc_action() say how to handle CRC errors in
+ * ancillary and critical chunks, and whether to use the data contained
+ * therein.  Note that it is impossible to "discard" data in a critical
+ * chunk.  For versions prior to 0.90, the action was always error/quit,
+ * whereas in version 0.90 and later, the action for CRC errors in ancillary
+ * chunks is warn/discard.  These values should NOT be changed.
+ *
+ *      value                       action:critical     action:ancillary
+ */
+#define PNG_CRC_DEFAULT       0  /* error/quit          warn/discard data */
+#define PNG_CRC_ERROR_QUIT    1  /* error/quit          error/quit        */
+#define PNG_CRC_WARN_DISCARD  2  /* (INVALID)           warn/discard data */
+#define PNG_CRC_WARN_USE      3  /* warn/use data       warn/use data     */
+#define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */
+#define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */
+
+#ifdef PNG_WRITE_SUPPORTED
+/* These functions give the user control over the scan-line filtering in
+ * libpng and the compression methods used by zlib.  These functions are
+ * mainly useful for testing, as the defaults should work with most users.
+ * Those users who are tight on memory or want faster performance at the
+ * expense of compression can modify them.  See the compression library
+ * header file (zlib.h) for an explanation of the compression functions.
+ */
+
+/* Set the filtering method(s) used by libpng.  Currently, the only valid
+ * value for "method" is 0.
+ */
+PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
+    int filters));
+#endif /* WRITE */
+
+/* Flags for png_set_filter() to say which filters to use.  The flags
+ * are chosen so that they don't conflict with real filter types
+ * below, in case they are supplied instead of the #defined constants.
+ * These values should NOT be changed.
+ */
+#define PNG_NO_FILTERS     0x00
+#define PNG_FILTER_NONE    0x08
+#define PNG_FILTER_SUB     0x10
+#define PNG_FILTER_UP      0x20
+#define PNG_FILTER_AVG     0x40
+#define PNG_FILTER_PAETH   0x80
+#define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP)
+#define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH)
+
+/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
+ * These defines should NOT be changed.
+ */
+#define PNG_FILTER_VALUE_NONE  0
+#define PNG_FILTER_VALUE_SUB   1
+#define PNG_FILTER_VALUE_UP    2
+#define PNG_FILTER_VALUE_AVG   3
+#define PNG_FILTER_VALUE_PAETH 4
+#define PNG_FILTER_VALUE_LAST  5
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
+PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
+    int heuristic_method, int num_weights, png_const_doublep filter_weights,
+    png_const_doublep filter_costs))
+PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
+    (png_structrp png_ptr, int heuristic_method, int num_weights,
+    png_const_fixed_point_p filter_weights,
+    png_const_fixed_point_p filter_costs))
+#endif /* WRITE_WEIGHTED_FILTER */
+
+/* The following are no longer used and will be removed from libpng-1.7: */
+#define PNG_FILTER_HEURISTIC_DEFAULT    0  /* Currently "UNWEIGHTED" */
+#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1  /* Used by libpng < 0.95 */
+#define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
+#define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */
+
+/* Set the library compression level.  Currently, valid values range from
+ * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
+ * (0 - no compression, 9 - "maximal" compression).  Note that tests have
+ * shown that zlib compression levels 3-6 usually perform as well as level 9
+ * for PNG images, and do considerably fewer calculations.  In the future,
+ * these values may not correspond directly to the zlib compression levels.
+ */
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
+    int level));
+
+PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
+    int mem_level));
+
+PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
+    int strategy));
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
+    int window_bits));
+
+PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
+    int method));
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+/* Also set zlib parameters for compressing non-IDAT chunks */
+PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
+    int level));
+
+PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
+    int mem_level));
+
+PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
+    int strategy));
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+PNG_EXPORT(225, void, png_set_text_compression_window_bits,
+    (png_structrp png_ptr, int window_bits));
+
+PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
+    int method));
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+#endif /* WRITE */
+
+/* These next functions are called for input/output, memory, and error
+ * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
+ * and call standard C I/O routines such as fread(), fwrite(), and
+ * fprintf().  These functions can be made to use other I/O routines
+ * at run time for those applications that need to handle I/O in a
+ * different manner by calling png_set_???_fn().  See libpng-manual.txt for
+ * more information.
+ */
+
+#ifdef PNG_STDIO_SUPPORTED
+/* Initialize the input/output for the PNG file to the default functions. */
+PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
+#endif
+
+/* Replace the (error and abort), and warning functions with user
+ * supplied functions.  If no messages are to be printed you must still
+ * write and use replacement functions. The replacement error_fn should
+ * still do a longjmp to the last setjmp location if you are using this
+ * method of error handling.  If error_fn or warning_fn is NULL, the
+ * default function will be used.
+ */
+
+PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
+    png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
+
+/* Return the user pointer associated with the error functions */
+PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
+
+/* Replace the default data output functions with a user supplied one(s).
+ * If buffered output is not used, then output_flush_fn can be set to NULL.
+ * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
+ * output_flush_fn will be ignored (and thus can be NULL).
+ * It is probably a mistake to use NULL for output_flush_fn if
+ * write_data_fn is not also NULL unless you have built libpng with
+ * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
+ * default flush function, which uses the standard *FILE structure, will
+ * be used.
+ */
+PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
+    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
+
+/* Replace the default data input function with a user supplied one. */
+PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
+    png_rw_ptr read_data_fn));
+
+/* Return the user pointer associated with the I/O functions */
+PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
+
+PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
+    png_read_status_ptr read_row_fn));
+
+PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
+    png_write_status_ptr write_row_fn));
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* Replace the default memory allocation functions with user supplied one(s). */
+PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
+    png_malloc_ptr malloc_fn, png_free_ptr free_fn));
+/* Return the user pointer associated with the memory functions */
+PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
+    png_user_transform_ptr read_user_transform_fn));
+#endif
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
+    png_user_transform_ptr write_user_transform_fn));
+#endif
+
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
+    png_voidp user_transform_ptr, int user_transform_depth,
+    int user_transform_channels));
+/* Return the user pointer associated with the user transform functions */
+PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
+    (png_const_structrp png_ptr));
+#endif
+
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+/* Return information about the row currently being processed.  Note that these
+ * APIs do not fail but will return unexpected results if called outside a user
+ * transform callback.  Also note that when transforming an interlaced image the
+ * row number is the row number within the sub-image of the interlace pass, so
+ * the value will increase to the height of the sub-image (not the full image)
+ * then reset to 0 for the next pass.
+ *
+ * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+ * find the output pixel (x,y) given an interlaced sub-image pixel
+ * (row,col,pass).  (See below for these macros.)
+ */
+PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
+PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
+#endif
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+/* This callback is called only for *unknown* chunks.  If
+ * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
+ * chunks to be treated as unknown, however in this case the callback must do
+ * any processing required by the chunk (e.g. by calling the appropriate
+ * png_set_ APIs.)
+ *
+ * There is no write support - on write, by default, all the chunks in the
+ * 'unknown' list are written in the specified position.
+ *
+ * The integer return from the callback function is interpreted thus:
+ *
+ * negative: An error occurred; png_chunk_error will be called.
+ *     zero: The chunk was not handled, the chunk will be saved. A critical
+ *           chunk will cause an error at this point unless it is to be saved.
+ * positive: The chunk was handled, libpng will ignore/discard it.
+ *
+ * See "INTERACTION WITH USER CHUNK CALLBACKS" below for important notes about
+ * how this behavior will change in libpng 1.7
+ */
+PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
+    png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
+#endif
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+/* Sets the function callbacks for the push reader, and a pointer to a
+ * user-defined structure available to the callback functions.
+ */
+PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
+    png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
+    png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
+
+/* Returns the user pointer associated with the push read functions */
+PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
+    (png_const_structrp png_ptr));
+
+/* Function to be called when data becomes available */
+PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
+    png_inforp info_ptr, png_bytep buffer, size_t buffer_size));
+
+/* A function which may be called *only* within png_process_data to stop the
+ * processing of any more data.  The function returns the number of bytes
+ * remaining, excluding any that libpng has cached internally.  A subsequent
+ * call to png_process_data must supply these bytes again.  If the argument
+ * 'save' is set to true the routine will first save all the pending data and
+ * will always return 0.
+ */
+PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save));
+
+/* A function which may be called *only* outside (after) a call to
+ * png_process_data.  It returns the number of bytes of data to skip in the
+ * input.  Normally it will return 0, but if it returns a non-zero value the
+ * application must skip than number of bytes of input data and pass the
+ * following data to the next call to png_process_data.
+ */
+PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
+
+/* Function that combines rows.  'new_row' is a flag that should come from
+ * the callback and be non-NULL if anything needs to be done; the library
+ * stores its own version of the new data internally and ignores the passed
+ * in value.
+ */
+PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
+    png_bytep old_row, png_const_bytep new_row));
+#endif /* PROGRESSIVE_READ */
+
+PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED);
+/* Added at libpng version 1.4.0 */
+PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED);
+
+/* Added at libpng version 1.2.4 */
+PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED);
+
+/* Frees a pointer allocated by png_malloc() */
+PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
+
+/* Free data that was allocated internally */
+PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 free_me, int num));
+
+/* Reassign the responsibility for freeing existing data, whether allocated
+ * by libpng or by the application; this works on the png_info structure passed
+ * in, without changing the state for other png_info structures.
+ */
+PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int freer, png_uint_32 mask));
+
+/* Assignments for png_data_freer */
+#define PNG_DESTROY_WILL_FREE_DATA 1
+#define PNG_SET_WILL_FREE_DATA 1
+#define PNG_USER_WILL_FREE_DATA 2
+/* Flags for png_ptr->free_me and info_ptr->free_me */
+#define PNG_FREE_HIST 0x0008U
+#define PNG_FREE_ICCP 0x0010U
+#define PNG_FREE_SPLT 0x0020U
+#define PNG_FREE_ROWS 0x0040U
+#define PNG_FREE_PCAL 0x0080U
+#define PNG_FREE_SCAL 0x0100U
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#  define PNG_FREE_UNKN 0x0200U
+#endif
+/*      PNG_FREE_LIST 0x0400U   removed in 1.6.0 because it is ignored */
+#define PNG_FREE_PLTE 0x1000U
+#define PNG_FREE_TRNS 0x2000U
+#define PNG_FREE_TEXT 0x4000U
+#define PNG_FREE_EXIF 0x8000U /* Added at libpng-1.6.31 */
+#define PNG_FREE_ALL  0xffffU
+#define PNG_FREE_MUL  0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
+
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
+    png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
+PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
+    png_voidp ptr), PNG_DEPRECATED);
+#endif
+
+#ifdef PNG_ERROR_TEXT_SUPPORTED
+/* Fatal error in PNG image of libpng - can't continue */
+PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
+    png_const_charp error_message), PNG_NORETURN);
+
+/* The same, but the chunk name is prepended to the error string. */
+PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
+    png_const_charp error_message), PNG_NORETURN);
+
+#else
+/* Fatal error in PNG image of libpng - can't continue */
+PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
+#  define png_error(s1,s2) png_err(s1)
+#  define png_chunk_error(s1,s2) png_err(s1)
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* Non-fatal error in libpng.  Can continue, but may have a problem. */
+PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
+    png_const_charp warning_message));
+
+/* Non-fatal error in libpng, chunk name is prepended to message. */
+PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
+    png_const_charp warning_message));
+#else
+#  define png_warning(s1,s2) ((void)(s1))
+#  define png_chunk_warning(s1,s2) ((void)(s1))
+#endif
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+/* Benign error in libpng.  Can continue, but may have a problem.
+ * User can choose whether to handle as a fatal error or as a warning. */
+PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
+    png_const_charp warning_message));
+
+#ifdef PNG_READ_SUPPORTED
+/* Same, chunk name is prepended to message (only during read) */
+PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
+    png_const_charp warning_message));
+#endif
+
+PNG_EXPORT(109, void, png_set_benign_errors,
+    (png_structrp png_ptr, int allowed));
+#else
+#  ifdef PNG_ALLOW_BENIGN_ERRORS
+#    define png_benign_error png_warning
+#    define png_chunk_benign_error png_chunk_warning
+#  else
+#    define png_benign_error png_error
+#    define png_chunk_benign_error png_chunk_error
+#  endif
+#endif
+
+/* The png_set_<chunk> functions are for storing values in the png_info_struct.
+ * Similarly, the png_get_<chunk> calls are used to read values from the
+ * png_info_struct, either storing the parameters in the passed variables, or
+ * setting pointers into the png_info_struct where the data is stored.  The
+ * png_get_<chunk> functions return a non-zero value if the data was available
+ * in info_ptr, or return zero and do not change any of the parameters if the
+ * data was not available.
+ *
+ * These functions should be used instead of directly accessing png_info
+ * to avoid problems with future changes in the size and internal layout of
+ * png_info_struct.
+ */
+/* Returns "flag" if chunk data is valid in info_ptr. */
+PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 flag));
+
+/* Returns number of bytes needed to hold a transformed row. */
+PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+/* Returns row_pointers, which is an array of pointers to scanlines that was
+ * returned from png_read_png().
+ */
+PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Set row_pointers, which is an array of pointers to scanlines for use
+ * by png_write_png().
+ */
+PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_bytepp row_pointers));
+#endif
+
+/* Returns number of color channels in image. */
+PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+/* Returns image width in pixels. */
+PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image height in pixels. */
+PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image bit_depth. */
+PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image color_type. */
+PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image filter_type. */
+PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image interlace_type. */
+PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image compression_type. */
+PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+
+/* Returns image resolution in pixels per meter, from pHYs chunk data. */
+PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+/* Returns pixel aspect ratio, computed from pHYs chunk data.  */
+PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+
+/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
+PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+#endif /* EASY_ACCESS */
+
+#ifdef PNG_READ_SUPPORTED
+/* Returns pointer to signature string read from PNG header */
+PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr));
+#endif
+
+#ifdef PNG_bKGD_SUPPORTED
+PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_color_16p *background));
+#endif
+
+#ifdef PNG_bKGD_SUPPORTED
+PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_color_16p background));
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
+    double *red_y, double *green_x, double *green_y, double *blue_x,
+    double *blue_y))
+PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
+    double *green_X, double *green_Y, double *green_Z, double *blue_X,
+    double *blue_Y, double *blue_Z))
+PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *int_white_x, png_fixed_point *int_white_y,
+    png_fixed_point *int_red_x, png_fixed_point *int_red_y,
+    png_fixed_point *int_green_x, png_fixed_point *int_green_y,
+    png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
+PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
+    png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
+    png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
+    png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
+    png_fixed_point *int_blue_Z))
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
+    png_inforp info_ptr,
+    double white_x, double white_y, double red_x, double red_y, double green_x,
+    double green_y, double blue_x, double blue_y))
+PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
+    png_inforp info_ptr, double red_X, double red_Y, double red_Z,
+    double green_X, double green_Y, double green_Z, double blue_X,
+    double blue_Y, double blue_Z))
+PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_fixed_point int_white_x,
+    png_fixed_point int_white_y, png_fixed_point int_red_x,
+    png_fixed_point int_red_y, png_fixed_point int_green_x,
+    png_fixed_point int_green_y, png_fixed_point int_blue_x,
+    png_fixed_point int_blue_y))
+PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
+    png_fixed_point int_red_Z, png_fixed_point int_green_X,
+    png_fixed_point int_green_Y, png_fixed_point int_green_Z,
+    png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
+    png_fixed_point int_blue_Z))
+#endif
+
+#ifdef PNG_eXIf_SUPPORTED
+PNG_EXPORT(246, png_uint_32, png_get_eXIf, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_bytep *exif));
+PNG_EXPORT(247, void, png_set_eXIf, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_bytep exif));
+
+PNG_EXPORT(248, png_uint_32, png_get_eXIf_1, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 *num_exif, png_bytep *exif));
+PNG_EXPORT(249, void, png_set_eXIf_1, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 num_exif, png_bytep exif));
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, double *file_gamma))
+PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *int_file_gamma))
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
+    png_inforp info_ptr, double file_gamma))
+PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_fixed_point int_file_gamma))
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_16p *hist));
+PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_uint_16p hist));
+#endif
+
+PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
+    int *bit_depth, int *color_type, int *interlace_method,
+    int *compression_method, int *filter_method));
+
+PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
+    int color_type, int interlace_method, int compression_method,
+    int filter_method));
+
+#ifdef PNG_oFFs_SUPPORTED
+PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
+   png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
+   int *unit_type));
+#endif
+
+#ifdef PNG_oFFs_SUPPORTED
+PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
+    int unit_type));
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
+    png_int_32 *X1, int *type, int *nparams, png_charp *units,
+    png_charpp *params));
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
+    int type, int nparams, png_const_charp units, png_charpp params));
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
+    int *unit_type));
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
+#endif
+
+PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
+   png_inforp info_ptr, png_colorp *palette, int *num_palette));
+
+PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
+    png_inforp info_ptr, png_const_colorp palette, int num_palette));
+
+#ifdef PNG_sBIT_SUPPORTED
+PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_color_8p *sig_bit));
+#endif
+
+#ifdef PNG_sBIT_SUPPORTED
+PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_color_8p sig_bit));
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, int *file_srgb_intent));
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int srgb_intent));
+PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int srgb_intent));
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_charpp name, int *compression_type,
+    png_bytepp profile, png_uint_32 *proflen));
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_charp name, int compression_type,
+    png_const_bytep profile, png_uint_32 proflen));
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_sPLT_tpp entries));
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+/* png_get_text also returns the number of text chunks in *num_text */
+PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_textp *text_ptr, int *num_text));
+#endif
+
+/* Note while png_set_text() will accept a structure whose text,
+ * language, and  translated keywords are NULL pointers, the structure
+ * returned by png_get_text will always contain regular
+ * zero-terminated C strings.  They might be empty strings but
+ * they will never be NULL pointers.
+ */
+
+#ifdef PNG_TEXT_SUPPORTED
+PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_textp text_ptr, int num_text));
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_timep *mod_time));
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_timep mod_time));
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
+    png_color_16p *trans_color));
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
+    png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
+    png_const_color_16p trans_color));
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, int *unit, double *width, double *height))
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+   defined(PNG_FLOATING_POINT_SUPPORTED)
+/* NOTE: this API is currently implemented using floating point arithmetic,
+ * consequently it can only be used on systems with floating point support.
+ * In any case the range of values supported by png_fixed_point is small and it
+ * is highly recommended that png_get_sCAL_s be used instead.
+ */
+PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
+    png_fixed_point *width, png_fixed_point *height))
+#endif
+PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
+    png_charpp swidth, png_charpp sheight));
+
+PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int unit, double width, double height))
+PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
+   png_inforp info_ptr, int unit, png_fixed_point width,
+   png_fixed_point height))
+PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int unit,
+    png_const_charp swidth, png_const_charp sheight));
+#endif /* sCAL */
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+/* Provide the default handling for all unknown chunks or, optionally, for
+ * specific unknown chunks.
+ *
+ * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
+ * ignored and the default was used, the per-chunk setting only had an effect on
+ * write.  If you wish to have chunk-specific handling on read in code that must
+ * work on earlier versions you must use a user chunk callback to specify the
+ * desired handling (keep or discard.)
+ *
+ * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below.  The
+ * parameter is interpreted as follows:
+ *
+ * READ:
+ *    PNG_HANDLE_CHUNK_AS_DEFAULT:
+ *       Known chunks: do normal libpng processing, do not keep the chunk (but
+ *          see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+ *       Unknown chunks: for a specific chunk use the global default, when used
+ *          as the default discard the chunk data.
+ *    PNG_HANDLE_CHUNK_NEVER:
+ *       Discard the chunk data.
+ *    PNG_HANDLE_CHUNK_IF_SAFE:
+ *       Keep the chunk data if the chunk is not critical else raise a chunk
+ *       error.
+ *    PNG_HANDLE_CHUNK_ALWAYS:
+ *       Keep the chunk data.
+ *
+ * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
+ * below.  Notice that specifying "AS_DEFAULT" as a global default is equivalent
+ * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
+ * it simply resets the behavior to the libpng default.
+ *
+ * INTERACTION WITH USER CHUNK CALLBACKS:
+ * The per-chunk handling is always used when there is a png_user_chunk_ptr
+ * callback and the callback returns 0; the chunk is then always stored *unless*
+ * it is critical and the per-chunk setting is other than ALWAYS.  Notice that
+ * the global default is *not* used in this case.  (In effect the per-chunk
+ * value is incremented to at least IF_SAFE.)
+ *
+ * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
+ * per-chunk defaults will be honored.  If you want to preserve the current
+ * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
+ * as the default - if you don't do this libpng 1.6 will issue a warning.
+ *
+ * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
+ * earlier simply return '1' (handled).
+ *
+ * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
+ *    If this is *not* set known chunks will always be handled by libpng and
+ *    will never be stored in the unknown chunk list.  Known chunks listed to
+ *    png_set_keep_unknown_chunks will have no effect.  If it is set then known
+ *    chunks listed with a keep other than AS_DEFAULT will *never* be processed
+ *    by libpng, in addition critical chunks must either be processed by the
+ *    callback or saved.
+ *
+ *    The IHDR and IEND chunks must not be listed.  Because this turns off the
+ *    default handling for chunks that would otherwise be recognized the
+ *    behavior of libpng transformations may well become incorrect!
+ *
+ * WRITE:
+ *    When writing chunks the options only apply to the chunks specified by
+ *    png_set_unknown_chunks (below), libpng will *always* write known chunks
+ *    required by png_set_ calls and will always write the core critical chunks
+ *    (as required for PLTE).
+ *
+ *    Each chunk in the png_set_unknown_chunks list is looked up in the
+ *    png_set_keep_unknown_chunks list to find the keep setting, this is then
+ *    interpreted as follows:
+ *
+ *    PNG_HANDLE_CHUNK_AS_DEFAULT:
+ *       Write safe-to-copy chunks and write other chunks if the global
+ *       default is set to _ALWAYS, otherwise don't write this chunk.
+ *    PNG_HANDLE_CHUNK_NEVER:
+ *       Do not write the chunk.
+ *    PNG_HANDLE_CHUNK_IF_SAFE:
+ *       Write the chunk if it is safe-to-copy, otherwise do not write it.
+ *    PNG_HANDLE_CHUNK_ALWAYS:
+ *       Write the chunk.
+ *
+ * Note that the default behavior is effectively the opposite of the read case -
+ * in read unknown chunks are not stored by default, in write they are written
+ * by default.  Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
+ * - on write the safe-to-copy bit is checked, on read the critical bit is
+ * checked and on read if the chunk is critical an error will be raised.
+ *
+ * num_chunks:
+ * ===========
+ *    If num_chunks is positive, then the "keep" parameter specifies the manner
+ *    for handling only those chunks appearing in the chunk_list array,
+ *    otherwise the chunk list array is ignored.
+ *
+ *    If num_chunks is 0 the "keep" parameter specifies the default behavior for
+ *    unknown chunks, as described above.
+ *
+ *    If num_chunks is negative, then the "keep" parameter specifies the manner
+ *    for handling all unknown chunks plus all chunks recognized by libpng
+ *    except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
+ *    be processed by libpng.
+ */
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
+    int keep, png_const_bytep chunk_list, int num_chunks));
+#endif /* HANDLE_AS_UNKNOWN */
+
+/* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
+ * the result is therefore true (non-zero) if special handling is required,
+ * false for the default handling.
+ */
+PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
+    png_const_bytep chunk_name));
+#endif /* SET_UNKNOWN_CHUNKS */
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_unknown_chunkp unknowns,
+    int num_unknowns));
+   /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
+    * unknowns to the location currently stored in the png_struct.  This is
+    * invariably the wrong value on write.  To fix this call the following API
+    * for each chunk in the list with the correct location.  If you know your
+    * code won't be compiled on earlier versions you can rely on
+    * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
+    * the correct thing.
+    */
+
+PNG_EXPORT(175, void, png_set_unknown_chunk_location,
+    (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
+
+PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
+    png_inforp info_ptr, png_unknown_chunkpp entries));
+#endif
+
+/* Png_free_data() will turn off the "valid" flag for anything it frees.
+ * If you need to turn it off for a chunk that your application has freed,
+ * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
+ */
+PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
+    png_inforp info_ptr, int mask));
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+/* The "params" pointer is currently not used and is for future expansion. */
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
+    int transforms, png_voidp params));
+#endif
+#ifdef PNG_WRITE_SUPPORTED
+PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
+    int transforms, png_voidp params));
+#endif
+#endif
+
+PNG_EXPORT(180, png_const_charp, png_get_copyright,
+    (png_const_structrp png_ptr));
+PNG_EXPORT(181, png_const_charp, png_get_header_ver,
+    (png_const_structrp png_ptr));
+PNG_EXPORT(182, png_const_charp, png_get_header_version,
+    (png_const_structrp png_ptr));
+PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
+    (png_const_structrp png_ptr));
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
+    png_uint_32 mng_features_permitted));
+#endif
+
+/* For use in png_set_keep_unknown, added to version 1.2.6 */
+#define PNG_HANDLE_CHUNK_AS_DEFAULT   0
+#define PNG_HANDLE_CHUNK_NEVER        1
+#define PNG_HANDLE_CHUNK_IF_SAFE      2
+#define PNG_HANDLE_CHUNK_ALWAYS       3
+#define PNG_HANDLE_CHUNK_LAST         4
+
+/* Strip the prepended error numbers ("#nnn ") from error and warning
+ * messages before passing them to the error or warning handler.
+ */
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
+    png_uint_32 strip_mode));
+#endif
+
+/* Added in libpng-1.2.6 */
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
+    png_uint_32 user_width_max, png_uint_32 user_height_max));
+PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
+    (png_const_structrp png_ptr));
+PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
+    (png_const_structrp png_ptr));
+/* Added in libpng-1.4.0 */
+PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
+    png_uint_32 user_chunk_cache_max));
+PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
+    (png_const_structrp png_ptr));
+/* Added in libpng-1.4.1 */
+PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
+    png_alloc_size_t user_chunk_cache_max));
+PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
+    (png_const_structrp png_ptr));
+#endif
+
+#if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
+PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+#endif
+
+PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr))
+#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
+PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
+    (png_const_structrp png_ptr, png_const_inforp info_ptr))
+#endif
+
+#  ifdef PNG_pHYs_SUPPORTED
+PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
+    png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
+    int *unit_type));
+#  endif /* pHYs */
+#endif  /* INCH_CONVERSIONS */
+
+/* Added in libpng-1.4.0 */
+#ifdef PNG_IO_STATE_SUPPORTED
+PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
+
+/* Removed from libpng 1.6; use png_get_io_chunk_type. */
+PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
+    PNG_DEPRECATED)
+
+PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
+    (png_const_structrp png_ptr));
+
+/* The flags returned by png_get_io_state() are the following: */
+#  define PNG_IO_NONE        0x0000   /* no I/O at this moment */
+#  define PNG_IO_READING     0x0001   /* currently reading */
+#  define PNG_IO_WRITING     0x0002   /* currently writing */
+#  define PNG_IO_SIGNATURE   0x0010   /* currently at the file signature */
+#  define PNG_IO_CHUNK_HDR   0x0020   /* currently at the chunk header */
+#  define PNG_IO_CHUNK_DATA  0x0040   /* currently at the chunk data */
+#  define PNG_IO_CHUNK_CRC   0x0080   /* currently at the chunk crc */
+#  define PNG_IO_MASK_OP     0x000f   /* current operation: reading/writing */
+#  define PNG_IO_MASK_LOC    0x00f0   /* current location: sig/hdr/data/crc */
+#endif /* IO_STATE */
+
+/* Interlace support.  The following macros are always defined so that if
+ * libpng interlace handling is turned off the macros may be used to handle
+ * interlaced images within the application.
+ */
+#define PNG_INTERLACE_ADAM7_PASSES 7
+
+/* Two macros to return the first row and first column of the original,
+ * full, image which appears in a given pass.  'pass' is in the range 0
+ * to 6 and the result is in the range 0 to 7.
+ */
+#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
+
+/* A macro to return the offset between pixels in the output row for a pair of
+ * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
+ * follows.  Note that ROW_OFFSET is the offset from one row to the next whereas
+ * COL_OFFSET is from one column to the next, within a row.
+ */
+#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
+#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
+
+/* Two macros to help evaluate the number of rows or columns in each
+ * pass.  This is expressed as a shift - effectively log2 of the number or
+ * rows or columns in each 8x8 tile of the original image.
+ */
+#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
+#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
+
+/* Hence two macros to determine the number of rows or columns in a given
+ * pass of an image given its height or width.  In fact these macros may
+ * return non-zero even though the sub-image is empty, because the other
+ * dimension may be empty for a small image.
+ */
+#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
+   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
+#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
+   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
+
+/* For the reader row callbacks (both progressive and sequential) it is
+ * necessary to find the row in the output image given a row in an interlaced
+ * image, so two more macros:
+ */
+#define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
+   (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
+#define PNG_COL_FROM_PASS_COL(x_in, pass) \
+   (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
+
+/* Two macros which return a boolean (0 or 1) saying whether the given row
+ * or column is in a particular pass.  These use a common utility macro that
+ * returns a mask for a given pass - the offset 'off' selects the row or
+ * column version.  The mask has the appropriate bit set for each column in
+ * the tile.
+ */
+#define PNG_PASS_MASK(pass,off) ( \
+   ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
+   ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
+
+#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
+   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
+#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
+   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
+
+#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
+/* With these routines we avoid an integer divide, which will be slower on
+ * most machines.  However, it does take more operations than the corresponding
+ * divide method, so it may be slower on a few RISC systems.  There are two
+ * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
+ *
+ * Note that the rounding factors are NOT supposed to be the same!  128 and
+ * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
+ * standard method.
+ *
+ * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
+ */
+
+ /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
+
+#  define png_composite(composite, fg, alpha, bg)        \
+   {                                                     \
+      png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
+          * (png_uint_16)(alpha)                         \
+          + (png_uint_16)(bg)*(png_uint_16)(255          \
+          - (png_uint_16)(alpha)) + 128);                \
+      (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); \
+   }
+
+#  define png_composite_16(composite, fg, alpha, bg)     \
+   {                                                     \
+      png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
+          * (png_uint_32)(alpha)                         \
+          + (png_uint_32)(bg)*(65535                     \
+          - (png_uint_32)(alpha)) + 32768);              \
+      (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); \
+   }
+
+#else  /* Standard method using integer division */
+
+#  define png_composite(composite, fg, alpha, bg)                      \
+   (composite) =                                                       \
+       (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) +  \
+       (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
+       127) / 255))
+
+#  define png_composite_16(composite, fg, alpha, bg)                       \
+   (composite) =                                                           \
+       (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
+       (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) +     \
+       32767) / 65535))
+#endif /* READ_COMPOSITE_NODIV */
+
+#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
+PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
+PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
+PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
+#endif
+
+PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
+    png_const_bytep buf));
+/* No png_get_int_16 -- may be added if there's a real need for it. */
+
+/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
+#endif
+#ifdef PNG_SAVE_INT_32_SUPPORTED
+PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
+#endif
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
+/* No png_save_int_16 -- may be added if there's a real need for it. */
+#endif
+
+#ifdef PNG_USE_READ_MACROS
+/* Inline macros to do direct reads of bytes from the input buffer.
+ * The png_get_int_32() routine assumes we are using two's complement
+ * format for negative values, which is almost certainly true.
+ */
+#  define PNG_get_uint_32(buf) \
+   (((png_uint_32)(*(buf)) << 24) + \
+    ((png_uint_32)(*((buf) + 1)) << 16) + \
+    ((png_uint_32)(*((buf) + 2)) << 8) + \
+    ((png_uint_32)(*((buf) + 3))))
+
+   /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+    * function) incorrectly returned a value of type png_uint_32.
+    */
+#  define PNG_get_uint_16(buf) \
+   ((png_uint_16) \
+    (((unsigned int)(*(buf)) << 8) + \
+    ((unsigned int)(*((buf) + 1)))))
+
+#  define PNG_get_int_32(buf) \
+   ((png_int_32)((*(buf) & 0x80) \
+    ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
+    : (png_int_32)png_get_uint_32(buf)))
+
+/* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
+ * but defining a macro name prefixed with PNG_PREFIX.
+ */
+#  ifndef PNG_PREFIX
+#    define png_get_uint_32(buf) PNG_get_uint_32(buf)
+#    define png_get_uint_16(buf) PNG_get_uint_16(buf)
+#    define png_get_int_32(buf)  PNG_get_int_32(buf)
+#  endif
+#else
+#  ifdef PNG_PREFIX
+   /* No macros; revert to the (redefined) function */
+#    define PNG_get_uint_32 (png_get_uint_32)
+#    define PNG_get_uint_16 (png_get_uint_16)
+#    define PNG_get_int_32  (png_get_int_32)
+#  endif
+#endif
+
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+PNG_EXPORT(242, void, png_set_check_for_invalid_index,
+    (png_structrp png_ptr, int allowed));
+#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
+    png_const_infop info_ptr));
+#  endif
+#endif /* CHECK_FOR_INVALID_INDEX */
+
+/*******************************************************************************
+ * Section 5: SIMPLIFIED API
+ *******************************************************************************
+ *
+ * Please read the documentation in libpng-manual.txt (TODO: write said
+ * documentation) if you don't understand what follows.
+ *
+ * The simplified API hides the details of both libpng and the PNG file format
+ * itself.  It allows PNG files to be read into a very limited number of
+ * in-memory bitmap formats or to be written from the same formats.  If these
+ * formats do not accommodate your needs then you can, and should, use the more
+ * sophisticated APIs above - these support a wide variety of in-memory formats
+ * and a wide variety of sophisticated transformations to those formats as well
+ * as a wide variety of APIs to manipulate ancillary information.
+ *
+ * To read a PNG file using the simplified API:
+ *
+ * 1) Declare a 'png_image' structure (see below) on the stack, set the
+ *    version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
+ *    (this is REQUIRED, your program may crash if you don't do it.)
+ * 2) Call the appropriate png_image_begin_read... function.
+ * 3) Set the png_image 'format' member to the required sample format.
+ * 4) Allocate a buffer for the image and, if required, the color-map.
+ * 5) Call png_image_finish_read to read the image and, if required, the
+ *    color-map into your buffers.
+ *
+ * There are no restrictions on the format of the PNG input itself; all valid
+ * color types, bit depths, and interlace methods are acceptable, and the
+ * input image is transformed as necessary to the requested in-memory format
+ * during the png_image_finish_read() step.  The only caveat is that if you
+ * request a color-mapped image from a PNG that is full-color or makes
+ * complex use of an alpha channel the transformation is extremely lossy and the
+ * result may look terrible.
+ *
+ * To write a PNG file using the simplified API:
+ *
+ * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
+ * 2) Initialize the members of the structure that describe the image, setting
+ *    the 'format' member to the format of the image samples.
+ * 3) Call the appropriate png_image_write... function with a pointer to the
+ *    image and, if necessary, the color-map to write the PNG data.
+ *
+ * png_image is a structure that describes the in-memory format of an image
+ * when it is being read or defines the in-memory format of an image that you
+ * need to write:
+ */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
+    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+
+#define PNG_IMAGE_VERSION 1
+
+typedef struct png_control *png_controlp;
+typedef struct
+{
+   png_controlp opaque;    /* Initialize to NULL, free with png_image_free */
+   png_uint_32  version;   /* Set to PNG_IMAGE_VERSION */
+   png_uint_32  width;     /* Image width in pixels (columns) */
+   png_uint_32  height;    /* Image height in pixels (rows) */
+   png_uint_32  format;    /* Image format as defined below */
+   png_uint_32  flags;     /* A bit mask containing informational flags */
+   png_uint_32  colormap_entries;
+                           /* Number of entries in the color-map */
+
+   /* In the event of an error or warning the following field will be set to a
+    * non-zero value and the 'message' field will contain a '\0' terminated
+    * string with the libpng error or warning message.  If both warnings and
+    * an error were encountered, only the error is recorded.  If there
+    * are multiple warnings, only the first one is recorded.
+    *
+    * The upper 30 bits of this value are reserved, the low two bits contain
+    * a value as follows:
+    */
+#  define PNG_IMAGE_WARNING 1
+#  define PNG_IMAGE_ERROR 2
+   /*
+    * The result is a two-bit code such that a value more than 1 indicates
+    * a failure in the API just called:
+    *
+    *    0 - no warning or error
+    *    1 - warning
+    *    2 - error
+    *    3 - error preceded by warning
+    */
+#  define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
+
+   png_uint_32  warning_or_error;
+
+   char         message[64];
+} png_image, *png_imagep;
+
+/* The samples of the image have one to four channels whose components have
+ * original values in the range 0 to 1.0:
+ *
+ * 1: A single gray or luminance channel (G).
+ * 2: A gray/luminance channel and an alpha channel (GA).
+ * 3: Three red, green, blue color channels (RGB).
+ * 4: Three color channels and an alpha channel (RGBA).
+ *
+ * The components are encoded in one of two ways:
+ *
+ * a) As a small integer, value 0..255, contained in a single byte.  For the
+ * alpha channel the original value is simply value/255.  For the color or
+ * luminance channels the value is encoded according to the sRGB specification
+ * and matches the 8-bit format expected by typical display devices.
+ *
+ * The color/gray channels are not scaled (pre-multiplied) by the alpha
+ * channel and are suitable for passing to color management software.
+ *
+ * b) As a value in the range 0..65535, contained in a 2-byte integer.  All
+ * channels can be converted to the original value by dividing by 65535; all
+ * channels are linear.  Color channels use the RGB encoding (RGB end-points) of
+ * the sRGB specification.  This encoding is identified by the
+ * PNG_FORMAT_FLAG_LINEAR flag below.
+ *
+ * When the simplified API needs to convert between sRGB and linear colorspaces,
+ * the actual sRGB transfer curve defined in the sRGB specification (see the
+ * article at <https://en.wikipedia.org/wiki/SRGB>) is used, not the gamma=1/2.2
+ * approximation used elsewhere in libpng.
+ *
+ * When an alpha channel is present it is expected to denote pixel coverage
+ * of the color or luminance channels and is returned as an associated alpha
+ * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
+ * value.
+ *
+ * The samples are either contained directly in the image data, between 1 and 8
+ * bytes per pixel according to the encoding, or are held in a color-map indexed
+ * by bytes in the image data.  In the case of a color-map the color-map entries
+ * are individual samples, encoded as above, and the image data has one byte per
+ * pixel to select the relevant sample from the color-map.
+ */
+
+/* PNG_FORMAT_*
+ *
+ * #defines to be used in png_image::format.  Each #define identifies a
+ * particular layout of sample data and, if present, alpha values.  There are
+ * separate defines for each of the two component encodings.
+ *
+ * A format is built up using single bit flag values.  All combinations are
+ * valid.  Formats can be built up from the flag values or you can use one of
+ * the predefined values below.  When testing formats always use the FORMAT_FLAG
+ * macros to test for individual features - future versions of the library may
+ * add new flags.
+ *
+ * When reading or writing color-mapped images the format should be set to the
+ * format of the entries in the color-map then png_image_{read,write}_colormap
+ * called to read or write the color-map and set the format correctly for the
+ * image data.  Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
+ *
+ * NOTE: libpng can be built with particular features disabled. If you see
+ * compiler errors because the definition of one of the following flags has been
+ * compiled out it is because libpng does not have the required support.  It is
+ * possible, however, for the libpng configuration to enable the format on just
+ * read or just write; in that case you may see an error at run time.  You can
+ * guard against this by checking for the definition of the appropriate
+ * "_SUPPORTED" macro, one of:
+ *
+ *    PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
+ */
+#define PNG_FORMAT_FLAG_ALPHA    0x01U /* format with an alpha channel */
+#define PNG_FORMAT_FLAG_COLOR    0x02U /* color format: otherwise grayscale */
+#define PNG_FORMAT_FLAG_LINEAR   0x04U /* 2-byte channels else 1-byte */
+#define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+#  define PNG_FORMAT_FLAG_BGR    0x10U /* BGR colors, else order is RGB */
+#endif
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+#  define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
+#endif
+
+#define PNG_FORMAT_FLAG_ASSOCIATED_ALPHA 0x40U /* alpha channel is associated */
+
+/* Commonly used formats have predefined macros.
+ *
+ * First the single byte (sRGB) formats:
+ */
+#define PNG_FORMAT_GRAY 0
+#define PNG_FORMAT_GA   PNG_FORMAT_FLAG_ALPHA
+#define PNG_FORMAT_AG   (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
+#define PNG_FORMAT_RGB  PNG_FORMAT_FLAG_COLOR
+#define PNG_FORMAT_BGR  (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
+#define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
+#define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
+#define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
+#define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
+
+/* Then the linear 2-byte formats.  When naming these "Y" is used to
+ * indicate a luminance (gray) channel.
+ */
+#define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
+#define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
+#define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
+#define PNG_FORMAT_LINEAR_RGB_ALPHA \
+   (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
+
+/* With color-mapped formats the image data is one byte for each pixel, the byte
+ * is an index into the color-map which is formatted as above.  To obtain a
+ * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
+ * to one of the above definitions, or you can use one of the definitions below.
+ */
+#define PNG_FORMAT_RGB_COLORMAP  (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_BGR_COLORMAP  (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
+
+/* PNG_IMAGE macros
+ *
+ * These are convenience macros to derive information from a png_image
+ * structure.  The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
+ * actual image sample values - either the entries in the color-map or the
+ * pixels in the image.  The PNG_IMAGE_PIXEL_ macros return corresponding values
+ * for the pixels and will always return 1 for color-mapped formats.  The
+ * remaining macros return information about the rows in the image and the
+ * complete image.
+ *
+ * NOTE: All the macros that take a png_image::format parameter are compile time
+ * constants if the format parameter is, itself, a constant.  Therefore these
+ * macros can be used in array declarations and case labels where required.
+ * Similarly the macros are also pre-processor constants (sizeof is not used) so
+ * they can be used in #if tests.
+ *
+ * First the information about the samples.
+ */
+#define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
+   (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
+   /* Return the total number of channels in a given format: 1..4 */
+
+#define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
+   ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
+   /* Return the size in bytes of a single component of a pixel or color-map
+    * entry (as appropriate) in the image: 1 or 2.
+    */
+
+#define PNG_IMAGE_SAMPLE_SIZE(fmt)\
+   (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
+   /* This is the size of the sample data for one sample.  If the image is
+    * color-mapped it is the size of one color-map entry (and image pixels are
+    * one byte in size), otherwise it is the size of one image pixel.
+    */
+
+#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
+   (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
+   /* The maximum size of the color-map required by the format expressed in a
+    * count of components.  This can be used to compile-time allocate a
+    * color-map:
+    *
+    * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
+    *
+    * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
+    *
+    * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+    * information from one of the png_image_begin_read_ APIs and dynamically
+    * allocate the required memory.
+    */
+
+/* Corresponding information about the pixels */
+#define PNG_IMAGE_PIXEL_(test,fmt)\
+   (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
+
+#define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
+   PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
+   /* The number of separate channels (components) in a pixel; 1 for a
+    * color-mapped image.
+    */
+
+#define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
+   PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
+   /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
+    * image.
+    */
+
+#define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
+   /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
+
+/* Information about the whole row, or whole image */
+#define PNG_IMAGE_ROW_STRIDE(image)\
+   (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
+   /* Return the total number of components in a single row of the image; this
+    * is the minimum 'row stride', the minimum count of components between each
+    * row.  For a color-mapped image this is the minimum number of bytes in a
+    * row.
+    *
+    * WARNING: this macro overflows for some images with more than one component
+    * and very large image widths.  libpng will refuse to process an image where
+    * this macro would overflow.
+    */
+
+#define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
+   (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
+   /* Return the size, in bytes, of an image buffer given a png_image and a row
+    * stride - the number of components to leave space for in each row.
+    *
+    * WARNING: this macro overflows a 32-bit integer for some large PNG images,
+    * libpng will refuse to process an image where such an overflow would occur.
+    */
+
+#define PNG_IMAGE_SIZE(image)\
+   PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
+   /* Return the size, in bytes, of the image in memory given just a png_image;
+    * the row stride is the minimum stride required for the image.
+    */
+
+#define PNG_IMAGE_COLORMAP_SIZE(image)\
+   (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
+   /* Return the size, in bytes, of the color-map of this image.  If the image
+    * format is not a color-map format this will return a size sufficient for
+    * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
+    * you don't want to allocate a color-map in this case.
+    */
+
+/* PNG_IMAGE_FLAG_*
+ *
+ * Flags containing additional information about the image are held in the
+ * 'flags' field of png_image.
+ */
+#define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
+   /* This indicates that the RGB values of the in-memory bitmap do not
+    * correspond to the red, green and blue end-points defined by sRGB.
+    */
+
+#define PNG_IMAGE_FLAG_FAST 0x02
+   /* On write emphasise speed over compression; the resultant PNG file will be
+    * larger but will be produced significantly faster, particular for large
+    * images.  Do not use this option for images which will be distributed, only
+    * used it when producing intermediate files that will be read back in
+    * repeatedly.  For a typical 24-bit image the option will double the read
+    * speed at the cost of increasing the image size by 25%, however for many
+    * more compressible images the PNG file can be 10 times larger with only a
+    * slight speed gain.
+    */
+
+#define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
+   /* On read if the image is a 16-bit per component image and there is no gAMA
+    * or sRGB chunk assume that the components are sRGB encoded.  Notice that
+    * images output by the simplified API always have gamma information; setting
+    * this flag only affects the interpretation of 16-bit images from an
+    * external source.  It is recommended that the application expose this flag
+    * to the user; the user can normally easily recognize the difference between
+    * linear and sRGB encoding.  This flag has no effect on write - the data
+    * passed to the write APIs must have the correct encoding (as defined
+    * above.)
+    *
+    * If the flag is not set (the default) input 16-bit per component data is
+    * assumed to be linear.
+    *
+    * NOTE: the flag can only be set after the png_image_begin_read_ call,
+    * because that call initializes the 'flags' field.
+    */
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+/* READ APIs
+ * ---------
+ *
+ * The png_image passed to the read APIs must have been initialized by setting
+ * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
+ */
+#ifdef PNG_STDIO_SUPPORTED
+PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
+   const char *file_name));
+   /* The named file is opened for read and the image header is filled in
+    * from the PNG header in the file.
+    */
+
+PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
+   FILE* file));
+   /* The PNG header is read from the stdio FILE object. */
+#endif /* STDIO */
+
+PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
+   png_const_voidp memory, size_t size));
+   /* The PNG header is read from the given memory buffer. */
+
+PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
+   png_const_colorp background, void *buffer, png_int_32 row_stride,
+   void *colormap));
+   /* Finish reading the image into the supplied buffer and clean up the
+    * png_image structure.
+    *
+    * row_stride is the step, in byte or 2-byte units as appropriate,
+    * between adjacent rows.  A positive stride indicates that the top-most row
+    * is first in the buffer - the normal top-down arrangement.  A negative
+    * stride indicates that the bottom-most row is first in the buffer.
+    *
+    * background need only be supplied if an alpha channel must be removed from
+    * a png_byte format and the removal is to be done by compositing on a solid
+    * color; otherwise it may be NULL and any composition will be done directly
+    * onto the buffer.  The value is an sRGB color to use for the background,
+    * for grayscale output the green channel is used.
+    *
+    * background must be supplied when an alpha channel must be removed from a
+    * single byte color-mapped output format, in other words if:
+    *
+    * 1) The original format from png_image_begin_read_from_* had
+    *    PNG_FORMAT_FLAG_ALPHA set.
+    * 2) The format set by the application does not.
+    * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
+    *    PNG_FORMAT_FLAG_LINEAR *not* set.
+    *
+    * For linear output removing the alpha channel is always done by compositing
+    * on black and background is ignored.
+    *
+    * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set.  It must
+    * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
+    * image->colormap_entries will be updated to the actual number of entries
+    * written to the colormap; this may be less than the original value.
+    */
+
+PNG_EXPORT(238, void, png_image_free, (png_imagep image));
+   /* Free any data allocated by libpng in image->opaque, setting the pointer to
+    * NULL.  May be called at any time after the structure is initialized.
+    */
+#endif /* SIMPLIFIED_READ */
+
+#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+/* WRITE APIS
+ * ----------
+ * For write you must initialize a png_image structure to describe the image to
+ * be written.  To do this use memset to set the whole structure to 0 then
+ * initialize fields describing your image.
+ *
+ * version: must be set to PNG_IMAGE_VERSION
+ * opaque: must be initialized to NULL
+ * width: image width in pixels
+ * height: image height in rows
+ * format: the format of the data (image and color-map) you wish to write
+ * flags: set to 0 unless one of the defined flags applies; set
+ *    PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
+ *    values do not correspond to the colors in sRGB.
+ * colormap_entries: set to the number of entries in the color-map (0 to 256)
+ */
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
+   const char *file, int convert_to_8bit, const void *buffer,
+   png_int_32 row_stride, const void *colormap));
+   /* Write the image to the named file. */
+
+PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
+   int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
+   const void *colormap));
+   /* Write the image to the given (FILE*). */
+#endif /* SIMPLIFIED_WRITE_STDIO */
+
+/* With all write APIs if image is in one of the linear formats with 16-bit
+ * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
+ * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
+ * encoded PNG file is written.
+ *
+ * With color-mapped data formats the colormap parameter point to a color-map
+ * with at least image->colormap_entries encoded in the specified format.  If
+ * the format is linear the written PNG color-map will be converted to sRGB
+ * regardless of the convert_to_8_bit flag.
+ *
+ * With all APIs row_stride is handled as in the read APIs - it is the spacing
+ * from one row to the next in component sized units (1 or 2 bytes) and if
+ * negative indicates a bottom-up row layout in the buffer.  If row_stride is
+ * zero, libpng will calculate it for you from the image width and number of
+ * channels.
+ *
+ * Note that the write API does not support interlacing, sub-8-bit pixels or
+ * most ancillary chunks.  If you need to write text chunks (e.g. for copyright
+ * notices) you need to use one of the other APIs.
+ */
+
+PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
+   png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit,
+   const void *buffer, png_int_32 row_stride, const void *colormap));
+   /* Write the image to the given memory buffer.  The function both writes the
+    * whole PNG data stream to *memory and updates *memory_bytes with the count
+    * of bytes written.
+    *
+    * 'memory' may be NULL.  In this case *memory_bytes is not read however on
+    * success the number of bytes which would have been written will still be
+    * stored in *memory_bytes.  On failure *memory_bytes will contain 0.
+    *
+    * If 'memory' is not NULL it must point to memory[*memory_bytes] of
+    * writeable memory.
+    *
+    * If the function returns success memory[*memory_bytes] (if 'memory' is not
+    * NULL) contains the written PNG data.  *memory_bytes will always be less
+    * than or equal to the original value.
+    *
+    * If the function returns false and *memory_bytes was not changed an error
+    * occurred during write.  If *memory_bytes was changed, or is not 0 if
+    * 'memory' was NULL, the write would have succeeded but for the memory
+    * buffer being too small.  *memory_bytes contains the required number of
+    * bytes and will be bigger that the original value.
+    */
+
+#define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\
+   row_stride, colormap)\
+   png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\
+         row_stride, colormap)
+   /* Return the amount of memory in 'size' required to compress this image.
+    * The png_image structure 'image' must be filled in as in the above
+    * function and must not be changed before the actual write call, the buffer
+    * and all other parameters must also be identical to that in the final
+    * write call.  The 'size' variable need not be initialized.
+    *
+    * NOTE: the macro returns true/false, if false is returned 'size' will be
+    * set to zero and the write failed and probably will fail if tried again.
+    */
+
+/* You can pre-allocate the buffer by making sure it is of sufficient size
+ * regardless of the amount of compression achieved.  The buffer size will
+ * always be bigger than the original image and it will never be filled.  The
+ * following macros are provided to assist in allocating the buffer.
+ */
+#define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height)
+   /* The number of uncompressed bytes in the PNG byte encoding of the image;
+    * uncompressing the PNG IDAT data will give this number of bytes.
+    *
+    * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this
+    * macro can because of the extra bytes used in the PNG byte encoding.  You
+    * need to avoid this macro if your image size approaches 2^30 in width or
+    * height.  The same goes for the remainder of these macros; they all produce
+    * bigger numbers than the actual in-memory image size.
+    */
+#ifndef PNG_ZLIB_MAX_SIZE
+#  define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U)
+   /* An upper bound on the number of compressed bytes given 'b' uncompressed
+    * bytes.  This is based on deflateBounds() in zlib; different
+    * implementations of zlib compression may conceivably produce more data so
+    * if your zlib implementation is not zlib itself redefine this macro
+    * appropriately.
+    */
+#endif
+
+#define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\
+   PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image))
+   /* An upper bound on the size of the data in the PNG IDAT chunks. */
+
+#define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\
+   ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\
+    (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\
+    12U+3U*(image).colormap_entries/*PLTE data*/+\
+    (((image).format&PNG_FORMAT_FLAG_ALPHA)?\
+    12U/*tRNS*/+(image).colormap_entries:0U):0U)+\
+    12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size))
+   /* A helper for the following macro; if your compiler cannot handle the
+    * following macro use this one with the result of
+    * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most
+    * compilers should handle this just fine.)
+    */
+
+#define PNG_IMAGE_PNG_SIZE_MAX(image)\
+   PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image))
+   /* An upper bound on the total length of the PNG data stream for 'image'.
+    * The result is of type png_alloc_size_t, on 32-bit systems this may
+    * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will
+    * run out of buffer space but return a corrected size which should work.
+    */
+#endif /* SIMPLIFIED_WRITE */
+/*******************************************************************************
+ *  END OF SIMPLIFIED API
+ ******************************************************************************/
+#endif /* SIMPLIFIED_{READ|WRITE} */
+
+/*******************************************************************************
+ * Section 6: IMPLEMENTATION OPTIONS
+ *******************************************************************************
+ *
+ * Support for arbitrary implementation-specific optimizations.  The API allows
+ * particular options to be turned on or off.  'Option' is the number of the
+ * option and 'onoff' is 0 (off) or non-0 (on).  The value returned is given
+ * by the PNG_OPTION_ defines below.
+ *
+ * HARDWARE: normally hardware capabilities, such as the Intel SSE instructions,
+ *           are detected at run time, however sometimes it may be impossible
+ *           to do this in user mode, in which case it is necessary to discover
+ *           the capabilities in an OS specific way.  Such capabilities are
+ *           listed here when libpng has support for them and must be turned
+ *           ON by the application if present.
+ *
+ * SOFTWARE: sometimes software optimizations actually result in performance
+ *           decrease on some architectures or systems, or with some sets of
+ *           PNG images.  'Software' options allow such optimizations to be
+ *           selected at run time.
+ */
+#ifdef PNG_SET_OPTION_SUPPORTED
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+#  define PNG_ARM_NEON   0 /* HARDWARE: ARM Neon SIMD instructions supported */
+#endif
+#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
+#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
+#ifdef PNG_MIPS_MSA_API_SUPPORTED
+#  define PNG_MIPS_MSA   6 /* HARDWARE: MIPS Msa SIMD instructions supported */
+#endif
+#ifdef PNG_DISABLE_ADLER32_CHECK_SUPPORTED
+#  define PNG_IGNORE_ADLER32 8 /* SOFTWARE: disable Adler32 check on IDAT */
+#endif
+#ifdef PNG_POWERPC_VSX_API_SUPPORTED
+#  define PNG_POWERPC_VSX   10 /* HARDWARE: PowerPC VSX SIMD instructions
+                                * supported */
+#endif
+#ifdef PNG_MIPS_MMI_API_SUPPORTED
+#  define PNG_MIPS_MMI   12 /* HARDWARE: MIPS MMI SIMD instructions supported */
+#endif
+
+#define PNG_OPTION_NEXT  14 /* Next option - numbers must be even */
+
+/* Return values: NOTE: there are four values and 'off' is *not* zero */
+#define PNG_OPTION_UNSET   0 /* Unset - defaults to off */
+#define PNG_OPTION_INVALID 1 /* Option number out of range */
+#define PNG_OPTION_OFF     2
+#define PNG_OPTION_ON      3
+
+PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
+   int onoff));
+#endif /* SET_OPTION */
+
+/*******************************************************************************
+ *  END OF HARDWARE AND SOFTWARE OPTIONS
+ ******************************************************************************/
+
+/* Maintainer: Put new public prototypes here ^, in libpng.3, in project
+ * defs, and in scripts/symbols.def.
+ */
+
+/* The last ordinal number (this is the *last* one already used; the next
+ * one to use is one more than this.)
+ */
+#ifdef PNG_EXPORT_LAST_ORDINAL
+  PNG_EXPORT_LAST_ORDINAL(249);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PNG_VERSION_INFO_ONLY */
+/* Do not put anything past this line */
+#endif /* PNG_H */
Index: /trunk/src/libs/libpng-1.6.45/pngconf.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngconf.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngconf.h	(revision 107811)
@@ -0,0 +1,623 @@
+
+/* pngconf.h - machine-configurable file for libpng
+ *
+ * libpng version 1.6.43
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Any machine specific code is near the front of this file, so if you
+ * are configuring libpng for a machine, you may want to read the section
+ * starting here down to where it starts to typedef png_color, png_text,
+ * and png_info.
+ */
+
+#ifndef PNGCONF_H
+#define PNGCONF_H
+
+#ifndef PNG_BUILDING_SYMBOL_TABLE /* else includes may cause problems */
+
+/* From libpng 1.6.0 libpng requires an ANSI X3.159-1989 ("ISOC90") compliant C
+ * compiler for correct compilation.  The following header files are required by
+ * the standard.  If your compiler doesn't provide these header files, or they
+ * do not match the standard, you will need to provide/improve them.
+ */
+#include <limits.h>
+#include <stddef.h>
+
+/* Library header files.  These header files are all defined by ISOC90; libpng
+ * expects conformant implementations, however, an ISOC90 conformant system need
+ * not provide these header files if the functionality cannot be implemented.
+ * In this case it will be necessary to disable the relevant parts of libpng in
+ * the build of pnglibconf.h.
+ *
+ * Prior to 1.6.0 string.h was included here; the API changes in 1.6.0 to not
+ * include this unnecessary header file.
+ */
+
+#ifdef PNG_STDIO_SUPPORTED
+   /* Required for the definition of FILE: */
+#  include <stdio.h>
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+   /* Required for the definition of jmp_buf and the declaration of longjmp: */
+#  include <setjmp.h>
+#endif
+
+#ifdef PNG_CONVERT_tIME_SUPPORTED
+   /* Required for struct tm: */
+#  include <time.h>
+#endif
+
+#endif /* PNG_BUILDING_SYMBOL_TABLE */
+
+/* Prior to 1.6.0, it was possible to turn off 'const' in declarations,
+ * using PNG_NO_CONST.  This is no longer supported.
+ */
+#define PNG_CONST const /* backward compatibility only */
+
+/* This controls optimization of the reading of 16-bit and 32-bit
+ * values from PNG files.  It can be set on a per-app-file basis: it
+ * just changes whether a macro is used when the function is called.
+ * The library builder sets the default; if read functions are not
+ * built into the library the macro implementation is forced on.
+ */
+#ifndef PNG_READ_INT_FUNCTIONS_SUPPORTED
+#  define PNG_USE_READ_MACROS
+#endif
+#if !defined(PNG_NO_USE_READ_MACROS) && !defined(PNG_USE_READ_MACROS)
+#  if PNG_DEFAULT_READ_MACROS
+#    define PNG_USE_READ_MACROS
+#  endif
+#endif
+
+/* COMPILER SPECIFIC OPTIONS.
+ *
+ * These options are provided so that a variety of difficult compilers
+ * can be used.  Some are fixed at build time (e.g. PNG_API_RULE
+ * below) but still have compiler specific implementations, others
+ * may be changed on a per-file basis when compiling against libpng.
+ */
+
+/* The PNGARG macro was used in versions of libpng prior to 1.6.0 to protect
+ * against legacy (pre ISOC90) compilers that did not understand function
+ * prototypes.  It is not required for modern C compilers.
+ */
+#ifndef PNGARG
+#  define PNGARG(arglist) arglist
+#endif
+
+/* Function calling conventions.
+ * =============================
+ * Normally it is not necessary to specify to the compiler how to call
+ * a function - it just does it - however on x86 systems derived from
+ * Microsoft and Borland C compilers ('IBM PC', 'DOS', 'Windows' systems
+ * and some others) there are multiple ways to call a function and the
+ * default can be changed on the compiler command line.  For this reason
+ * libpng specifies the calling convention of every exported function and
+ * every function called via a user supplied function pointer.  This is
+ * done in this file by defining the following macros:
+ *
+ * PNGAPI    Calling convention for exported functions.
+ * PNGCBAPI  Calling convention for user provided (callback) functions.
+ * PNGCAPI   Calling convention used by the ANSI-C library (required
+ *           for longjmp callbacks and sometimes used internally to
+ *           specify the calling convention for zlib).
+ *
+ * These macros should never be overridden.  If it is necessary to
+ * change calling convention in a private build this can be done
+ * by setting PNG_API_RULE (which defaults to 0) to one of the values
+ * below to select the correct 'API' variants.
+ *
+ * PNG_API_RULE=0 Use PNGCAPI - the 'C' calling convention - throughout.
+ *                This is correct in every known environment.
+ * PNG_API_RULE=1 Use the operating system convention for PNGAPI and
+ *                the 'C' calling convention (from PNGCAPI) for
+ *                callbacks (PNGCBAPI).  This is no longer required
+ *                in any known environment - if it has to be used
+ *                please post an explanation of the problem to the
+ *                libpng mailing list.
+ *
+ * These cases only differ if the operating system does not use the C
+ * calling convention, at present this just means the above cases
+ * (x86 DOS/Windows systems) and, even then, this does not apply to
+ * Cygwin running on those systems.
+ *
+ * Note that the value must be defined in pnglibconf.h so that what
+ * the application uses to call the library matches the conventions
+ * set when building the library.
+ */
+
+/* Symbol export
+ * =============
+ * When building a shared library it is almost always necessary to tell
+ * the compiler which symbols to export.  The png.h macro 'PNG_EXPORT'
+ * is used to mark the symbols.  On some systems these symbols can be
+ * extracted at link time and need no special processing by the compiler,
+ * on other systems the symbols are flagged by the compiler and just
+ * the declaration requires a special tag applied (unfortunately) in a
+ * compiler dependent way.  Some systems can do either.
+ *
+ * A small number of older systems also require a symbol from a DLL to
+ * be flagged to the program that calls it.  This is a problem because
+ * we do not know in the header file included by application code that
+ * the symbol will come from a shared library, as opposed to a statically
+ * linked one.  For this reason the application must tell us by setting
+ * the magic flag PNG_USE_DLL to turn on the special processing before
+ * it includes png.h.
+ *
+ * Four additional macros are used to make this happen:
+ *
+ * PNG_IMPEXP The magic (if any) to cause a symbol to be exported from
+ *            the build or imported if PNG_USE_DLL is set - compiler
+ *            and system specific.
+ *
+ * PNG_EXPORT_TYPE(type) A macro that pre or appends PNG_IMPEXP to
+ *                       'type', compiler specific.
+ *
+ * PNG_DLL_EXPORT Set to the magic to use during a libpng build to
+ *                make a symbol exported from the DLL.  Not used in the
+ *                public header files; see pngpriv.h for how it is used
+ *                in the libpng build.
+ *
+ * PNG_DLL_IMPORT Set to the magic to force the libpng symbols to come
+ *                from a DLL - used to define PNG_IMPEXP when
+ *                PNG_USE_DLL is set.
+ */
+
+/* System specific discovery.
+ * ==========================
+ * This code is used at build time to find PNG_IMPEXP, the API settings
+ * and PNG_EXPORT_TYPE(), it may also set a macro to indicate the DLL
+ * import processing is possible.  On Windows systems it also sets
+ * compiler-specific macros to the values required to change the calling
+ * conventions of the various functions.
+ */
+#if defined(_WIN32) || defined(__WIN32__) || defined(__NT__) || \
+    defined(__CYGWIN__)
+  /* Windows system (DOS doesn't support DLLs).  Includes builds under Cygwin or
+   * MinGW on any architecture currently supported by Windows.  Also includes
+   * Watcom builds but these need special treatment because they are not
+   * compatible with GCC or Visual C because of different calling conventions.
+   */
+#  if PNG_API_RULE == 2
+   /* If this line results in an error, either because __watcall is not
+    * understood or because of a redefine just below you cannot use *this*
+    * build of the library with the compiler you are using.  *This* build was
+    * build using Watcom and applications must also be built using Watcom!
+    */
+#    define PNGCAPI __watcall
+#  endif
+
+#  if defined(__GNUC__) || (defined(_MSC_VER) && (_MSC_VER >= 800))
+#    define PNGCAPI __cdecl
+#    if PNG_API_RULE == 1
+   /* If this line results in an error __stdcall is not understood and
+    * PNG_API_RULE should not have been set to '1'.
+    */
+#      define PNGAPI __stdcall
+#    endif
+#  else
+   /* An older compiler, or one not detected (erroneously) above,
+    * if necessary override on the command line to get the correct
+    * variants for the compiler.
+    */
+#    ifndef PNGCAPI
+#      define PNGCAPI _cdecl
+#    endif
+#    if PNG_API_RULE == 1 && !defined(PNGAPI)
+#      define PNGAPI _stdcall
+#    endif
+#  endif /* compiler/api */
+
+  /* NOTE: PNGCBAPI always defaults to PNGCAPI. */
+
+#  if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
+#     error "PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed"
+#  endif
+
+#  if (defined(_MSC_VER) && _MSC_VER < 800) ||\
+      (defined(__BORLANDC__) && __BORLANDC__ < 0x500)
+   /* older Borland and MSC
+    * compilers used '__export' and required this to be after
+    * the type.
+    */
+#    ifndef PNG_EXPORT_TYPE
+#      define PNG_EXPORT_TYPE(type) type PNG_IMPEXP
+#    endif
+#    define PNG_DLL_EXPORT __export
+#  else /* newer compiler */
+#    define PNG_DLL_EXPORT __declspec(dllexport)
+#    ifndef PNG_DLL_IMPORT
+#      define PNG_DLL_IMPORT __declspec(dllimport)
+#    endif
+#  endif /* compiler */
+
+#else /* !Windows */
+#  if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
+#    define PNGAPI _System
+#  else /* !Windows/x86 && !OS/2 */
+   /* Use the defaults, or define PNG*API on the command line (but
+    * this will have to be done for every compile!)
+    */
+#  endif /* other system, !OS/2 */
+#endif /* !Windows/x86 */
+
+/* Now do all the defaulting . */
+#ifndef PNGCAPI
+#  define PNGCAPI
+#endif
+#ifndef PNGCBAPI
+#  define PNGCBAPI PNGCAPI
+#endif
+#ifndef PNGAPI
+#  define PNGAPI PNGCAPI
+#endif
+
+/* PNG_IMPEXP may be set on the compilation system command line or (if not set)
+ * then in an internal header file when building the library, otherwise (when
+ * using the library) it is set here.
+ */
+#ifndef PNG_IMPEXP
+#  if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT)
+   /* This forces use of a DLL, disallowing static linking */
+#    define PNG_IMPEXP PNG_DLL_IMPORT
+#  endif
+
+#  ifndef PNG_IMPEXP
+#    define PNG_IMPEXP
+#  endif
+#endif
+
+/* In 1.5.2 the definition of PNG_FUNCTION has been changed to always treat
+ * 'attributes' as a storage class - the attributes go at the start of the
+ * function definition, and attributes are always appended regardless of the
+ * compiler.  This considerably simplifies these macros but may cause problems
+ * if any compilers both need function attributes and fail to handle them as
+ * a storage class (this is unlikely.)
+ */
+#ifndef PNG_FUNCTION
+#  define PNG_FUNCTION(type, name, args, attributes) attributes type name args
+#endif
+
+#ifndef PNG_EXPORT_TYPE
+#  define PNG_EXPORT_TYPE(type) PNG_IMPEXP type
+#endif
+
+   /* The ordinal value is only relevant when preprocessing png.h for symbol
+    * table entries, so we discard it here.  See the .dfn files in the
+    * scripts directory.
+    */
+
+#ifndef PNG_EXPORTA
+#  define PNG_EXPORTA(ordinal, type, name, args, attributes) \
+      PNG_FUNCTION(PNG_EXPORT_TYPE(type), (PNGAPI name), PNGARG(args), \
+      PNG_LINKAGE_API attributes)
+#endif
+
+/* ANSI-C (C90) does not permit a macro to be invoked with an empty argument,
+ * so make something non-empty to satisfy the requirement:
+ */
+#define PNG_EMPTY /*empty list*/
+
+#define PNG_EXPORT(ordinal, type, name, args) \
+   PNG_EXPORTA(ordinal, type, name, args, PNG_EMPTY)
+
+/* Use PNG_REMOVED to comment out a removed interface. */
+#ifndef PNG_REMOVED
+#  define PNG_REMOVED(ordinal, type, name, args, attributes)
+#endif
+
+#ifndef PNG_CALLBACK
+#  define PNG_CALLBACK(type, name, args) type (PNGCBAPI name) PNGARG(args)
+#endif
+
+/* Support for compiler specific function attributes.  These are used
+ * so that where compiler support is available incorrect use of API
+ * functions in png.h will generate compiler warnings.
+ *
+ * Added at libpng-1.2.41.
+ */
+
+#ifndef PNG_NO_PEDANTIC_WARNINGS
+#  ifndef PNG_PEDANTIC_WARNINGS_SUPPORTED
+#    define PNG_PEDANTIC_WARNINGS_SUPPORTED
+#  endif
+#endif
+
+#ifdef PNG_PEDANTIC_WARNINGS_SUPPORTED
+  /* Support for compiler specific function attributes.  These are used
+   * so that where compiler support is available, incorrect use of API
+   * functions in png.h will generate compiler warnings.  Added at libpng
+   * version 1.2.41.  Disabling these removes the warnings but may also produce
+   * less efficient code.
+   */
+#  if defined(__clang__) && defined(__has_attribute)
+   /* Clang defines both __clang__ and __GNUC__. Check __clang__ first. */
+#    if !defined(PNG_USE_RESULT) && __has_attribute(__warn_unused_result__)
+#      define PNG_USE_RESULT __attribute__((__warn_unused_result__))
+#    endif
+#    if !defined(PNG_NORETURN) && __has_attribute(__noreturn__)
+#      define PNG_NORETURN __attribute__((__noreturn__))
+#    endif
+#    if !defined(PNG_ALLOCATED) && __has_attribute(__malloc__)
+#      define PNG_ALLOCATED __attribute__((__malloc__))
+#    endif
+#    if !defined(PNG_DEPRECATED) && __has_attribute(__deprecated__)
+#      define PNG_DEPRECATED __attribute__((__deprecated__))
+#    endif
+#    if !defined(PNG_PRIVATE)
+#      ifdef __has_extension
+#        if __has_extension(attribute_unavailable_with_message)
+#          define PNG_PRIVATE __attribute__((__unavailable__(\
+             "This function is not exported by libpng.")))
+#        endif
+#      endif
+#    endif
+#    ifndef PNG_RESTRICT
+#      define PNG_RESTRICT __restrict
+#    endif
+
+#  elif defined(__GNUC__)
+#    ifndef PNG_USE_RESULT
+#      define PNG_USE_RESULT __attribute__((__warn_unused_result__))
+#    endif
+#    ifndef PNG_NORETURN
+#      define PNG_NORETURN   __attribute__((__noreturn__))
+#    endif
+#    if __GNUC__ >= 3
+#      ifndef PNG_ALLOCATED
+#        define PNG_ALLOCATED  __attribute__((__malloc__))
+#      endif
+#      ifndef PNG_DEPRECATED
+#        define PNG_DEPRECATED __attribute__((__deprecated__))
+#      endif
+#      ifndef PNG_PRIVATE
+#        if 0 /* Doesn't work so we use deprecated instead*/
+#          define PNG_PRIVATE \
+            __attribute__((warning("This function is not exported by libpng.")))
+#        else
+#          define PNG_PRIVATE \
+            __attribute__((__deprecated__))
+#        endif
+#      endif
+#      if ((__GNUC__ > 3) || !defined(__GNUC_MINOR__) || (__GNUC_MINOR__ >= 1))
+#        ifndef PNG_RESTRICT
+#          define PNG_RESTRICT __restrict
+#        endif
+#      endif /* __GNUC__.__GNUC_MINOR__ > 3.0 */
+#    endif /* __GNUC__ >= 3 */
+
+#  elif defined(_MSC_VER)  && (_MSC_VER >= 1300)
+#    ifndef PNG_USE_RESULT
+#      define PNG_USE_RESULT /* not supported */
+#    endif
+#    ifndef PNG_NORETURN
+#      define PNG_NORETURN   __declspec(noreturn)
+#    endif
+#    ifndef PNG_ALLOCATED
+#      if (_MSC_VER >= 1400)
+#        define PNG_ALLOCATED __declspec(restrict)
+#      endif
+#    endif
+#    ifndef PNG_DEPRECATED
+#      define PNG_DEPRECATED __declspec(deprecated)
+#    endif
+#    ifndef PNG_PRIVATE
+#      define PNG_PRIVATE __declspec(deprecated)
+#    endif
+#    ifndef PNG_RESTRICT
+#      if (_MSC_VER >= 1400)
+#        define PNG_RESTRICT __restrict
+#      endif
+#    endif
+
+#  elif defined(__WATCOMC__)
+#    ifndef PNG_RESTRICT
+#      define PNG_RESTRICT __restrict
+#    endif
+#  endif
+#endif /* PNG_PEDANTIC_WARNINGS */
+
+#ifndef PNG_DEPRECATED
+#  define PNG_DEPRECATED  /* Use of this function is deprecated */
+#endif
+#ifndef PNG_USE_RESULT
+#  define PNG_USE_RESULT  /* The result of this function must be checked */
+#endif
+#ifndef PNG_NORETURN
+#  define PNG_NORETURN    /* This function does not return */
+#endif
+#ifndef PNG_ALLOCATED
+#  define PNG_ALLOCATED   /* The result of the function is new memory */
+#endif
+#ifndef PNG_PRIVATE
+#  define PNG_PRIVATE     /* This is a private libpng function */
+#endif
+#ifndef PNG_RESTRICT
+#  define PNG_RESTRICT    /* The C99 "restrict" feature */
+#endif
+
+#ifndef PNG_FP_EXPORT     /* A floating point API. */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+#     define PNG_FP_EXPORT(ordinal, type, name, args)\
+         PNG_EXPORT(ordinal, type, name, args);
+#  else                   /* No floating point APIs */
+#     define PNG_FP_EXPORT(ordinal, type, name, args)
+#  endif
+#endif
+#ifndef PNG_FIXED_EXPORT  /* A fixed point API. */
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+#     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
+         PNG_EXPORT(ordinal, type, name, args);
+#  else                   /* No fixed point APIs */
+#     define PNG_FIXED_EXPORT(ordinal, type, name, args)
+#  endif
+#endif
+
+#ifndef PNG_BUILDING_SYMBOL_TABLE
+/* Some typedefs to get us started.  These should be safe on most of the common
+ * platforms.
+ *
+ * png_uint_32 and png_int_32 may, currently, be larger than required to hold a
+ * 32-bit value however this is not normally advisable.
+ *
+ * png_uint_16 and png_int_16 should always be two bytes in size - this is
+ * verified at library build time.
+ *
+ * png_byte must always be one byte in size.
+ *
+ * The checks below use constants from limits.h, as defined by the ISOC90
+ * standard.
+ */
+#if CHAR_BIT == 8 && UCHAR_MAX == 255
+   typedef unsigned char png_byte;
+#else
+#  error "libpng requires 8-bit bytes"
+#endif
+
+#if INT_MIN == -32768 && INT_MAX == 32767
+   typedef int png_int_16;
+#elif SHRT_MIN == -32768 && SHRT_MAX == 32767
+   typedef short png_int_16;
+#else
+#  error "libpng requires a signed 16-bit type"
+#endif
+
+#if UINT_MAX == 65535
+   typedef unsigned int png_uint_16;
+#elif USHRT_MAX == 65535
+   typedef unsigned short png_uint_16;
+#else
+#  error "libpng requires an unsigned 16-bit type"
+#endif
+
+#if INT_MIN < -2147483646 && INT_MAX > 2147483646
+   typedef int png_int_32;
+#elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646
+   typedef long int png_int_32;
+#else
+#  error "libpng requires a signed 32-bit (or more) type"
+#endif
+
+#if UINT_MAX > 4294967294U
+   typedef unsigned int png_uint_32;
+#elif ULONG_MAX > 4294967294U
+   typedef unsigned long int png_uint_32;
+#else
+#  error "libpng requires an unsigned 32-bit (or more) type"
+#endif
+
+/* Prior to 1.6.0, it was possible to disable the use of size_t and ptrdiff_t.
+ * From 1.6.0 onwards, an ISO C90 compiler, as well as a standard-compliant
+ * behavior of sizeof and ptrdiff_t are required.
+ * The legacy typedefs are provided here for backwards compatibility.
+ */
+typedef size_t png_size_t;
+typedef ptrdiff_t png_ptrdiff_t;
+
+/* libpng needs to know the maximum value of 'size_t' and this controls the
+ * definition of png_alloc_size_t, below.  This maximum value of size_t limits
+ * but does not control the maximum allocations the library makes - there is
+ * direct application control of this through png_set_user_limits().
+ */
+#ifndef PNG_SMALL_SIZE_T
+   /* Compiler specific tests for systems where size_t is known to be less than
+    * 32 bits (some of these systems may no longer work because of the lack of
+    * 'far' support; see above.)
+    */
+#  if (defined(__TURBOC__) && !defined(__FLAT__)) ||\
+   (defined(_MSC_VER) && defined(MAXSEG_64K))
+#     define PNG_SMALL_SIZE_T
+#  endif
+#endif
+
+/* png_alloc_size_t is guaranteed to be no smaller than size_t, and no smaller
+ * than png_uint_32.  Casts from size_t or png_uint_32 to png_alloc_size_t are
+ * not necessary; in fact, it is recommended not to use them at all, so that
+ * the compiler can complain when something turns out to be problematic.
+ *
+ * Casts in the other direction (from png_alloc_size_t to size_t or
+ * png_uint_32) should be explicitly applied; however, we do not expect to
+ * encounter practical situations that require such conversions.
+ *
+ * PNG_SMALL_SIZE_T must be defined if the maximum value of size_t is less than
+ * 4294967295 - i.e. less than the maximum value of png_uint_32.
+ */
+#ifdef PNG_SMALL_SIZE_T
+   typedef png_uint_32 png_alloc_size_t;
+#else
+   typedef size_t png_alloc_size_t;
+#endif
+
+/* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler
+ * implementations of Intel CPU specific support of user-mode segmented address
+ * spaces, where 16-bit pointers address more than 65536 bytes of memory using
+ * separate 'segment' registers.  The implementation requires two different
+ * types of pointer (only one of which includes the segment value.)
+ *
+ * If required this support is available in version 1.2 of libpng and may be
+ * available in versions through 1.5, although the correctness of the code has
+ * not been verified recently.
+ */
+
+/* Typedef for floating-point numbers that are converted to fixed-point with a
+ * multiple of 100,000, e.g., gamma
+ */
+typedef png_int_32 png_fixed_point;
+
+/* Add typedefs for pointers */
+typedef void                  * png_voidp;
+typedef const void            * png_const_voidp;
+typedef png_byte              * png_bytep;
+typedef const png_byte        * png_const_bytep;
+typedef png_uint_32           * png_uint_32p;
+typedef const png_uint_32     * png_const_uint_32p;
+typedef png_int_32            * png_int_32p;
+typedef const png_int_32      * png_const_int_32p;
+typedef png_uint_16           * png_uint_16p;
+typedef const png_uint_16     * png_const_uint_16p;
+typedef png_int_16            * png_int_16p;
+typedef const png_int_16      * png_const_int_16p;
+typedef char                  * png_charp;
+typedef const char            * png_const_charp;
+typedef png_fixed_point       * png_fixed_point_p;
+typedef const png_fixed_point * png_const_fixed_point_p;
+typedef size_t                * png_size_tp;
+typedef const size_t          * png_const_size_tp;
+
+#ifdef PNG_STDIO_SUPPORTED
+typedef FILE            * png_FILE_p;
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+typedef double       * png_doublep;
+typedef const double * png_const_doublep;
+#endif
+
+/* Pointers to pointers; i.e. arrays */
+typedef png_byte        * * png_bytepp;
+typedef png_uint_32     * * png_uint_32pp;
+typedef png_int_32      * * png_int_32pp;
+typedef png_uint_16     * * png_uint_16pp;
+typedef png_int_16      * * png_int_16pp;
+typedef const char      * * png_const_charpp;
+typedef char            * * png_charpp;
+typedef png_fixed_point * * png_fixed_point_pp;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+typedef double          * * png_doublepp;
+#endif
+
+/* Pointers to pointers to pointers; i.e., pointer to array */
+typedef char            * * * png_charppp;
+
+#endif /* PNG_BUILDING_SYMBOL_TABLE */
+
+#endif /* PNGCONF_H */
Index: /trunk/src/libs/libpng-1.6.45/pngdebug.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngdebug.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngdebug.h	(revision 107811)
@@ -0,0 +1,153 @@
+
+/* pngdebug.h - Debugging macros for libpng, also used in pngtest.c
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2013 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Define PNG_DEBUG at compile time for debugging information.  Higher
+ * numbers for PNG_DEBUG mean more debugging information.  This has
+ * only been added since version 0.95 so it is not implemented throughout
+ * libpng yet, but more support will be added as needed.
+ *
+ * png_debug[1-2]?(level, message ,arg{0-2})
+ *   Expands to a statement (either a simple expression or a compound
+ *   do..while(0) statement) that outputs a message with parameter
+ *   substitution if PNG_DEBUG is defined to 2 or more.  If PNG_DEBUG
+ *   is undefined, 0 or 1 every png_debug expands to a simple expression
+ *   (actually ((void)0)).
+ *
+ *   level: level of detail of message, starting at 0.  A level 'n'
+ *          message is preceded by 'n' 3-space indentations (not implemented
+ *          on Microsoft compilers unless PNG_DEBUG_FILE is also
+ *          defined, to allow debug DLL compilation with no standard IO).
+ *   message: a printf(3) style text string.  A trailing '\n' is added
+ *            to the message.
+ *   arg: 0 to 2 arguments for printf(3) style substitution in message.
+ */
+#ifndef PNGDEBUG_H
+#define PNGDEBUG_H
+/* These settings control the formatting of messages in png.c and pngerror.c */
+/* Moved to pngdebug.h at 1.5.0 */
+#  ifndef PNG_LITERAL_SHARP
+#    define PNG_LITERAL_SHARP 0x23
+#  endif
+#  ifndef PNG_LITERAL_LEFT_SQUARE_BRACKET
+#    define PNG_LITERAL_LEFT_SQUARE_BRACKET 0x5b
+#  endif
+#  ifndef PNG_LITERAL_RIGHT_SQUARE_BRACKET
+#    define PNG_LITERAL_RIGHT_SQUARE_BRACKET 0x5d
+#  endif
+#  ifndef PNG_STRING_NEWLINE
+#    define PNG_STRING_NEWLINE "\n"
+#  endif
+
+#ifdef PNG_DEBUG
+#  if (PNG_DEBUG > 0)
+#    if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)
+#      include <crtdbg.h>
+#      if (PNG_DEBUG > 1)
+#        ifndef _DEBUG
+#          define _DEBUG
+#        endif
+#        ifndef png_debug
+#          define png_debug(l,m)  _RPT0(_CRT_WARN,m PNG_STRING_NEWLINE)
+#        endif
+#        ifndef png_debug1
+#          define png_debug1(l,m,p1)  _RPT1(_CRT_WARN,m PNG_STRING_NEWLINE,p1)
+#        endif
+#        ifndef png_debug2
+#          define png_debug2(l,m,p1,p2) \
+             _RPT2(_CRT_WARN,m PNG_STRING_NEWLINE,p1,p2)
+#        endif
+#      endif
+#    else /* PNG_DEBUG_FILE || !_MSC_VER */
+#      ifndef PNG_STDIO_SUPPORTED
+#        include <stdio.h> /* not included yet */
+#      endif
+#      ifndef PNG_DEBUG_FILE
+#        define PNG_DEBUG_FILE stderr
+#      endif /* PNG_DEBUG_FILE */
+
+#      if (PNG_DEBUG > 1)
+#        ifdef __STDC__
+#          ifndef png_debug
+#            define png_debug(l,m) \
+       do { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : "")))); \
+       } while (0)
+#          endif
+#          ifndef png_debug1
+#            define png_debug1(l,m,p1) \
+       do { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : ""))),p1); \
+       } while (0)
+#          endif
+#          ifndef png_debug2
+#            define png_debug2(l,m,p1,p2) \
+       do { \
+       int num_tabs=l; \
+       fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? "   " : \
+         (num_tabs==2 ? "      " : (num_tabs>2 ? "         " : ""))),p1,p2);\
+       } while (0)
+#          endif
+#        else /* __STDC __ */
+#          ifndef png_debug
+#            define png_debug(l,m) \
+       do { \
+       int num_tabs=l; \
+       char format[256]; \
+       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+         m,PNG_STRING_NEWLINE); \
+       fprintf(PNG_DEBUG_FILE,format); \
+       } while (0)
+#          endif
+#          ifndef png_debug1
+#            define png_debug1(l,m,p1) \
+       do { \
+       int num_tabs=l; \
+       char format[256]; \
+       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+         m,PNG_STRING_NEWLINE); \
+       fprintf(PNG_DEBUG_FILE,format,p1); \
+       } while (0)
+#          endif
+#          ifndef png_debug2
+#            define png_debug2(l,m,p1,p2) \
+       do { \
+       int num_tabs=l; \
+       char format[256]; \
+       snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+         (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+         m,PNG_STRING_NEWLINE); \
+       fprintf(PNG_DEBUG_FILE,format,p1,p2); \
+       } while (0)
+#          endif
+#        endif /* __STDC __ */
+#      endif /* (PNG_DEBUG > 1) */
+
+#    endif /* _MSC_VER */
+#  endif /* (PNG_DEBUG > 0) */
+#endif /* PNG_DEBUG */
+#ifndef png_debug
+#  define png_debug(l, m) ((void)0)
+#endif
+#ifndef png_debug1
+#  define png_debug1(l, m, p1) ((void)0)
+#endif
+#ifndef png_debug2
+#  define png_debug2(l, m, p1, p2) ((void)0)
+#endif
+#endif /* PNGDEBUG_H */
Index: /trunk/src/libs/libpng-1.6.45/pngerror.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngerror.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngerror.c	(revision 107811)
@@ -0,0 +1,957 @@
+
+/* pngerror.c - stub functions for i/o and memory allocation
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all error handling.  Users who
+ * need special error handling are expected to write replacement functions
+ * and use png_set_error_fn() to use those functions.  See the instructions
+ * at each function.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr,
+    png_const_charp error_message)),PNG_NORETURN);
+
+#ifdef PNG_WARNINGS_SUPPORTED
+static void /* PRIVATE */
+png_default_warning PNGARG((png_const_structrp png_ptr,
+    png_const_charp warning_message));
+#endif /* WARNINGS */
+
+/* This function is called whenever there is a fatal error.  This function
+ * should not be changed.  If there is a need to handle errors differently,
+ * you should supply a replacement error function and use png_set_error_fn()
+ * to replace the error function at run-time.
+ */
+#ifdef PNG_ERROR_TEXT_SUPPORTED
+PNG_FUNCTION(void,PNGAPI
+png_error,(png_const_structrp png_ptr, png_const_charp error_message),
+    PNG_NORETURN)
+{
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   char msg[16];
+   if (png_ptr != NULL)
+   {
+      if ((png_ptr->flags &
+         (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
+      {
+         if (*error_message == PNG_LITERAL_SHARP)
+         {
+            /* Strip "#nnnn " from beginning of error message. */
+            int offset;
+            for (offset = 1; offset<15; offset++)
+               if (error_message[offset] == ' ')
+                  break;
+
+            if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
+            {
+               int i;
+               for (i = 0; i < offset - 1; i++)
+                  msg[i] = error_message[i + 1];
+               msg[i - 1] = '\0';
+               error_message = msg;
+            }
+
+            else
+               error_message += offset;
+         }
+
+         else
+         {
+            if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
+            {
+               msg[0] = '0';
+               msg[1] = '\0';
+               error_message = msg;
+            }
+         }
+      }
+   }
+#endif
+   if (png_ptr != NULL && png_ptr->error_fn != NULL)
+      (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr),
+          error_message);
+
+   /* If the custom handler doesn't exist, or if it returns,
+      use the default handler, which will not return. */
+   png_default_error(png_ptr, error_message);
+}
+#else
+PNG_FUNCTION(void,PNGAPI
+png_err,(png_const_structrp png_ptr),PNG_NORETURN)
+{
+   /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed
+    * erroneously as '\0', instead of the empty string "".  This was
+    * apparently an error, introduced in libpng-1.2.20, and png_default_error
+    * will crash in this case.
+    */
+   if (png_ptr != NULL && png_ptr->error_fn != NULL)
+      (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), "");
+
+   /* If the custom handler doesn't exist, or if it returns,
+      use the default handler, which will not return. */
+   png_default_error(png_ptr, "");
+}
+#endif /* ERROR_TEXT */
+
+/* Utility to safely appends strings to a buffer.  This never errors out so
+ * error checking is not required in the caller.
+ */
+size_t
+png_safecat(png_charp buffer, size_t bufsize, size_t pos,
+    png_const_charp string)
+{
+   if (buffer != NULL && pos < bufsize)
+   {
+      if (string != NULL)
+         while (*string != '\0' && pos < bufsize-1)
+           buffer[pos++] = *string++;
+
+      buffer[pos] = '\0';
+   }
+
+   return pos;
+}
+
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string.
+ */
+png_charp
+png_format_number(png_const_charp start, png_charp end, int format,
+    png_alloc_size_t number)
+{
+   int count = 0;    /* number of digits output */
+   int mincount = 1; /* minimum number required */
+   int output = 0;   /* digit output (for the fixed point format) */
+
+   *--end = '\0';
+
+   /* This is written so that the loop always runs at least once, even with
+    * number zero.
+    */
+   while (end > start && (number != 0 || count < mincount))
+   {
+
+      static const char digits[] = "0123456789ABCDEF";
+
+      switch (format)
+      {
+         case PNG_NUMBER_FORMAT_fixed:
+            /* Needs five digits (the fraction) */
+            mincount = 5;
+            if (output != 0 || number % 10 != 0)
+            {
+               *--end = digits[number % 10];
+               output = 1;
+            }
+            number /= 10;
+            break;
+
+         case PNG_NUMBER_FORMAT_02u:
+            /* Expects at least 2 digits. */
+            mincount = 2;
+            /* FALLTHROUGH */
+
+         case PNG_NUMBER_FORMAT_u:
+            *--end = digits[number % 10];
+            number /= 10;
+            break;
+
+         case PNG_NUMBER_FORMAT_02x:
+            /* This format expects at least two digits */
+            mincount = 2;
+            /* FALLTHROUGH */
+
+         case PNG_NUMBER_FORMAT_x:
+            *--end = digits[number & 0xf];
+            number >>= 4;
+            break;
+
+         default: /* an error */
+            number = 0;
+            break;
+      }
+
+      /* Keep track of the number of digits added */
+      ++count;
+
+      /* Float a fixed number here: */
+      if ((format == PNG_NUMBER_FORMAT_fixed) && (count == 5) && (end > start))
+      {
+         /* End of the fraction, but maybe nothing was output?  In that case
+          * drop the decimal point.  If the number is a true zero handle that
+          * here.
+          */
+         if (output != 0)
+            *--end = '.';
+         else if (number == 0) /* and !output */
+            *--end = '0';
+      }
+   }
+
+   return end;
+}
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* This function is called whenever there is a non-fatal error.  This function
+ * should not be changed.  If there is a need to handle warnings differently,
+ * you should supply a replacement warning function and use
+ * png_set_error_fn() to replace the warning function at run-time.
+ */
+void PNGAPI
+png_warning(png_const_structrp png_ptr, png_const_charp warning_message)
+{
+   int offset = 0;
+   if (png_ptr != NULL)
+   {
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   if ((png_ptr->flags &
+       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
+#endif
+      {
+         if (*warning_message == PNG_LITERAL_SHARP)
+         {
+            for (offset = 1; offset < 15; offset++)
+               if (warning_message[offset] == ' ')
+                  break;
+         }
+      }
+   }
+   if (png_ptr != NULL && png_ptr->warning_fn != NULL)
+      (*(png_ptr->warning_fn))(png_constcast(png_structrp,png_ptr),
+          warning_message + offset);
+   else
+      png_default_warning(png_ptr, warning_message + offset);
+}
+
+/* These functions support 'formatted' warning messages with up to
+ * PNG_WARNING_PARAMETER_COUNT parameters.  In the format string the parameter
+ * is introduced by @<number>, where 'number' starts at 1.  This follows the
+ * standard established by X/Open for internationalizable error messages.
+ */
+void
+png_warning_parameter(png_warning_parameters p, int number,
+    png_const_charp string)
+{
+   if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT)
+      (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string);
+}
+
+void
+png_warning_parameter_unsigned(png_warning_parameters p, int number, int format,
+    png_alloc_size_t value)
+{
+   char buffer[PNG_NUMBER_BUFFER_SIZE] = {0};
+   png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value));
+}
+
+void
+png_warning_parameter_signed(png_warning_parameters p, int number, int format,
+    png_int_32 value)
+{
+   png_alloc_size_t u;
+   png_charp str;
+   char buffer[PNG_NUMBER_BUFFER_SIZE] = {0};
+
+   /* Avoid overflow by doing the negate in a png_alloc_size_t: */
+   u = (png_alloc_size_t)value;
+   if (value < 0)
+      u = ~u + 1;
+
+   str = PNG_FORMAT_NUMBER(buffer, format, u);
+
+   if (value < 0 && str > buffer)
+      *--str = '-';
+
+   png_warning_parameter(p, number, str);
+}
+
+void
+png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p,
+    png_const_charp message)
+{
+   /* The internal buffer is just 192 bytes - enough for all our messages,
+    * overflow doesn't happen because this code checks!  If someone figures
+    * out how to send us a message longer than 192 bytes, all that will
+    * happen is that the message will be truncated appropriately.
+    */
+   size_t i = 0; /* Index in the msg[] buffer: */
+   char msg[192];
+
+   /* Each iteration through the following loop writes at most one character
+    * to msg[i++] then returns here to validate that there is still space for
+    * the trailing '\0'.  It may (in the case of a parameter) read more than
+    * one character from message[]; it must check for '\0' and continue to the
+    * test if it finds the end of string.
+    */
+   while (i<(sizeof msg)-1 && *message != '\0')
+   {
+      /* '@' at end of string is now just printed (previously it was skipped);
+       * it is an error in the calling code to terminate the string with @.
+       */
+      if (p != NULL && *message == '@' && message[1] != '\0')
+      {
+         int parameter_char = *++message; /* Consume the '@' */
+         static const char valid_parameters[] = "123456789";
+         int parameter = 0;
+
+         /* Search for the parameter digit, the index in the string is the
+          * parameter to use.
+          */
+         while (valid_parameters[parameter] != parameter_char &&
+            valid_parameters[parameter] != '\0')
+            ++parameter;
+
+         /* If the parameter digit is out of range it will just get printed. */
+         if (parameter < PNG_WARNING_PARAMETER_COUNT)
+         {
+            /* Append this parameter */
+            png_const_charp parm = p[parameter];
+            png_const_charp pend = p[parameter] + (sizeof p[parameter]);
+
+            /* No need to copy the trailing '\0' here, but there is no guarantee
+             * that parm[] has been initialized, so there is no guarantee of a
+             * trailing '\0':
+             */
+            while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend)
+               msg[i++] = *parm++;
+
+            /* Consume the parameter digit too: */
+            ++message;
+            continue;
+         }
+
+         /* else not a parameter and there is a character after the @ sign; just
+          * copy that.  This is known not to be '\0' because of the test above.
+          */
+      }
+
+      /* At this point *message can't be '\0', even in the bad parameter case
+       * above where there is a lone '@' at the end of the message string.
+       */
+      msg[i++] = *message++;
+   }
+
+   /* i is always less than (sizeof msg), so: */
+   msg[i] = '\0';
+
+   /* And this is the formatted message. It may be larger than
+    * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these
+    * are not (currently) formatted.
+    */
+   png_warning(png_ptr, msg);
+}
+#endif /* WARNINGS */
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+void PNGAPI
+png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
+{
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
+   {
+#     ifdef PNG_READ_SUPPORTED
+         if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+            png_ptr->chunk_name != 0)
+            png_chunk_warning(png_ptr, error_message);
+         else
+#     endif
+      png_warning(png_ptr, error_message);
+   }
+
+   else
+   {
+#     ifdef PNG_READ_SUPPORTED
+         if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+            png_ptr->chunk_name != 0)
+            png_chunk_error(png_ptr, error_message);
+         else
+#     endif
+      png_error(png_ptr, error_message);
+   }
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+      PNG_UNUSED(error_message)
+#  endif
+}
+
+void /* PRIVATE */
+png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
+{
+   if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
+      png_warning(png_ptr, error_message);
+   else
+      png_error(png_ptr, error_message);
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+      PNG_UNUSED(error_message)
+#  endif
+}
+
+void /* PRIVATE */
+png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
+{
+   if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
+      png_warning(png_ptr, error_message);
+   else
+      png_error(png_ptr, error_message);
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+      PNG_UNUSED(error_message)
+#  endif
+}
+#endif /* BENIGN_ERRORS */
+
+#define PNG_MAX_ERROR_TEXT 196 /* Currently limited by profile_error in png.c */
+#if defined(PNG_WARNINGS_SUPPORTED) || \
+   (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED))
+/* These utilities are used internally to build an error message that relates
+ * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
+ * which is used to prefix the message.  The message is limited in length
+ * to 63 bytes. The name characters are output as hex digits wrapped in []
+ * if the character is invalid.
+ */
+#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+static const char png_digit[16] = {
+   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+   'A', 'B', 'C', 'D', 'E', 'F'
+};
+
+static void /* PRIVATE */
+png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
+    error_message)
+{
+   png_uint_32 chunk_name = png_ptr->chunk_name;
+   int iout = 0, ishift = 24;
+
+   while (ishift >= 0)
+   {
+      int c = (int)(chunk_name >> ishift) & 0xff;
+
+      ishift -= 8;
+      if (isnonalpha(c) != 0)
+      {
+         buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
+         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
+         buffer[iout++] = png_digit[c & 0x0f];
+         buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET;
+      }
+
+      else
+      {
+         buffer[iout++] = (char)c;
+      }
+   }
+
+   if (error_message == NULL)
+      buffer[iout] = '\0';
+
+   else
+   {
+      int iin = 0;
+
+      buffer[iout++] = ':';
+      buffer[iout++] = ' ';
+
+      while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
+         buffer[iout++] = error_message[iin++];
+
+      /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
+      buffer[iout] = '\0';
+   }
+}
+#endif /* WARNINGS || ERROR_TEXT */
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
+PNG_FUNCTION(void,PNGAPI
+png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message),
+    PNG_NORETURN)
+{
+   char msg[18+PNG_MAX_ERROR_TEXT];
+   if (png_ptr == NULL)
+      png_error(png_ptr, error_message);
+
+   else
+   {
+      png_format_buffer(png_ptr, msg, error_message);
+      png_error(png_ptr, msg);
+   }
+}
+#endif /* READ && ERROR_TEXT */
+
+#ifdef PNG_WARNINGS_SUPPORTED
+void PNGAPI
+png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message)
+{
+   char msg[18+PNG_MAX_ERROR_TEXT];
+   if (png_ptr == NULL)
+      png_warning(png_ptr, warning_message);
+
+   else
+   {
+      png_format_buffer(png_ptr, msg, warning_message);
+      png_warning(png_ptr, msg);
+   }
+}
+#endif /* WARNINGS */
+
+#ifdef PNG_READ_SUPPORTED
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+void PNGAPI
+png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
+    error_message)
+{
+   if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
+      png_chunk_warning(png_ptr, error_message);
+
+   else
+      png_chunk_error(png_ptr, error_message);
+
+#  ifndef PNG_ERROR_TEXT_SUPPORTED
+      PNG_UNUSED(error_message)
+#  endif
+}
+#endif
+#endif /* READ */
+
+void /* PRIVATE */
+png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
+{
+#  ifndef PNG_WARNINGS_SUPPORTED
+      PNG_UNUSED(message)
+#  endif
+
+   /* This is always supported, but for just read or just write it
+    * unconditionally does the right thing.
+    */
+#  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+#  endif
+
+#  ifdef PNG_READ_SUPPORTED
+      {
+         if (error < PNG_CHUNK_ERROR)
+            png_chunk_warning(png_ptr, message);
+
+         else
+            png_chunk_benign_error(png_ptr, message);
+      }
+#  endif
+
+#  if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
+      else if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+#  endif
+
+#  ifdef PNG_WRITE_SUPPORTED
+      {
+         if (error < PNG_CHUNK_WRITE_ERROR)
+            png_app_warning(png_ptr, message);
+
+         else
+            png_app_error(png_ptr, message);
+      }
+#  endif
+}
+
+#ifdef PNG_ERROR_TEXT_SUPPORTED
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_FUNCTION(void,
+png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
+{
+#  define fixed_message "fixed point overflow in "
+#  define fixed_message_ln ((sizeof fixed_message)-1)
+   unsigned int  iin;
+   char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
+   memcpy(msg, fixed_message, fixed_message_ln);
+   iin = 0;
+   if (name != NULL)
+      while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
+      {
+         msg[fixed_message_ln + iin] = name[iin];
+         ++iin;
+      }
+   msg[fixed_message_ln + iin] = 0;
+   png_error(png_ptr, msg);
+}
+#endif
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+/* This API only exists if ANSI-C style error handling is used,
+ * otherwise it is necessary for png_default_error to be overridden.
+ */
+jmp_buf* PNGAPI
+png_set_longjmp_fn(png_structrp png_ptr, png_longjmp_ptr longjmp_fn,
+    size_t jmp_buf_size)
+{
+   /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value
+    * and it must not change after that.  Libpng doesn't care how big the
+    * buffer is, just that it doesn't change.
+    *
+    * If the buffer size is no *larger* than the size of jmp_buf when libpng is
+    * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0
+    * semantics that this call will not fail.  If the size is larger, however,
+    * the buffer is allocated and this may fail, causing the function to return
+    * NULL.
+    */
+   if (png_ptr == NULL)
+      return NULL;
+
+   if (png_ptr->jmp_buf_ptr == NULL)
+   {
+      png_ptr->jmp_buf_size = 0; /* not allocated */
+
+      if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local))
+         png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local;
+
+      else
+      {
+         png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *,
+             png_malloc_warn(png_ptr, jmp_buf_size));
+
+         if (png_ptr->jmp_buf_ptr == NULL)
+            return NULL; /* new NULL return on OOM */
+
+         png_ptr->jmp_buf_size = jmp_buf_size;
+      }
+   }
+
+   else /* Already allocated: check the size */
+   {
+      size_t size = png_ptr->jmp_buf_size;
+
+      if (size == 0)
+      {
+         size = (sizeof png_ptr->jmp_buf_local);
+         if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local)
+         {
+            /* This is an internal error in libpng: somehow we have been left
+             * with a stack allocated jmp_buf when the application regained
+             * control.  It's always possible to fix this up, but for the moment
+             * this is a png_error because that makes it easy to detect.
+             */
+            png_error(png_ptr, "Libpng jmp_buf still allocated");
+            /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */
+         }
+      }
+
+      if (size != jmp_buf_size)
+      {
+         png_warning(png_ptr, "Application jmp_buf size changed");
+         return NULL; /* caller will probably crash: no choice here */
+      }
+   }
+
+   /* Finally fill in the function, now we have a satisfactory buffer. It is
+    * valid to change the function on every call.
+    */
+   png_ptr->longjmp_fn = longjmp_fn;
+   return png_ptr->jmp_buf_ptr;
+}
+
+void /* PRIVATE */
+png_free_jmpbuf(png_structrp png_ptr)
+{
+   if (png_ptr != NULL)
+   {
+      jmp_buf *jb = png_ptr->jmp_buf_ptr;
+
+      /* A size of 0 is used to indicate a local, stack, allocation of the
+       * pointer; used here and in png.c
+       */
+      if (jb != NULL && png_ptr->jmp_buf_size > 0)
+      {
+
+         /* This stuff is so that a failure to free the error control structure
+          * does not leave libpng in a state with no valid error handling: the
+          * free always succeeds, if there is an error it gets ignored.
+          */
+         if (jb != &png_ptr->jmp_buf_local)
+         {
+            /* Make an internal, libpng, jmp_buf to return here */
+            jmp_buf free_jmp_buf;
+
+            if (!setjmp(free_jmp_buf))
+            {
+               png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */
+               png_ptr->jmp_buf_size = 0; /* stack allocation */
+               png_ptr->longjmp_fn = longjmp;
+               png_free(png_ptr, jb); /* Return to setjmp on error */
+            }
+         }
+      }
+
+      /* *Always* cancel everything out: */
+      png_ptr->jmp_buf_size = 0;
+      png_ptr->jmp_buf_ptr = NULL;
+      png_ptr->longjmp_fn = 0;
+   }
+}
+#endif
+
+/* This is the default error handling function.  Note that replacements for
+ * this function MUST NOT RETURN, or the program will likely crash.  This
+ * function is used by default, or if the program supplies NULL for the
+ * error function pointer in png_set_error_fn().
+ */
+static PNG_FUNCTION(void /* PRIVATE */,
+png_default_error,(png_const_structrp png_ptr, png_const_charp error_message),
+    PNG_NORETURN)
+{
+#ifdef PNG_CONSOLE_IO_SUPPORTED
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   /* Check on NULL only added in 1.5.4 */
+   if (error_message != NULL && *error_message == PNG_LITERAL_SHARP)
+   {
+      /* Strip "#nnnn " from beginning of error message. */
+      int offset;
+      char error_number[16];
+      for (offset = 0; offset<15; offset++)
+      {
+         error_number[offset] = error_message[offset + 1];
+         if (error_message[offset] == ' ')
+            break;
+      }
+
+      if ((offset > 1) && (offset < 15))
+      {
+         error_number[offset - 1] = '\0';
+         fprintf(stderr, "libpng error no. %s: %s",
+             error_number, error_message + offset + 1);
+         fprintf(stderr, PNG_STRING_NEWLINE);
+      }
+
+      else
+      {
+         fprintf(stderr, "libpng error: %s, offset=%d",
+             error_message, offset);
+         fprintf(stderr, PNG_STRING_NEWLINE);
+      }
+   }
+   else
+#endif
+   {
+      fprintf(stderr, "libpng error: %s", error_message ? error_message :
+         "undefined");
+      fprintf(stderr, PNG_STRING_NEWLINE);
+   }
+#else
+   PNG_UNUSED(error_message) /* Make compiler happy */
+#endif
+   png_longjmp(png_ptr, 1);
+}
+
+PNG_FUNCTION(void,PNGAPI
+png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
+{
+#ifdef PNG_SETJMP_SUPPORTED
+   if (png_ptr != NULL && png_ptr->longjmp_fn != NULL &&
+       png_ptr->jmp_buf_ptr != NULL)
+      png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(val)
+#endif
+
+   /* If control reaches this point, png_longjmp() must not return. The only
+    * choice is to terminate the whole process (or maybe the thread); to do
+    * this the ANSI-C abort() function is used unless a different method is
+    * implemented by overriding the default configuration setting for
+    * PNG_ABORT().
+    */
+   PNG_ABORT();
+}
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* This function is called when there is a warning, but the library thinks
+ * it can continue anyway.  Replacement functions don't have to do anything
+ * here if you don't want them to.  In the default configuration, png_ptr is
+ * not used, but it is passed in case it may be useful.
+ */
+static void /* PRIVATE */
+png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message)
+{
+#ifdef PNG_CONSOLE_IO_SUPPORTED
+#  ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   if (*warning_message == PNG_LITERAL_SHARP)
+   {
+      int offset;
+      char warning_number[16];
+      for (offset = 0; offset < 15; offset++)
+      {
+         warning_number[offset] = warning_message[offset + 1];
+         if (warning_message[offset] == ' ')
+            break;
+      }
+
+      if ((offset > 1) && (offset < 15))
+      {
+         warning_number[offset + 1] = '\0';
+         fprintf(stderr, "libpng warning no. %s: %s",
+             warning_number, warning_message + offset);
+         fprintf(stderr, PNG_STRING_NEWLINE);
+      }
+
+      else
+      {
+         fprintf(stderr, "libpng warning: %s",
+             warning_message);
+         fprintf(stderr, PNG_STRING_NEWLINE);
+      }
+   }
+   else
+#  endif
+
+   {
+      fprintf(stderr, "libpng warning: %s", warning_message);
+      fprintf(stderr, PNG_STRING_NEWLINE);
+   }
+#else
+   PNG_UNUSED(warning_message) /* Make compiler happy */
+#endif
+   PNG_UNUSED(png_ptr) /* Make compiler happy */
+}
+#endif /* WARNINGS */
+
+/* This function is called when the application wants to use another method
+ * of handling errors and warnings.  Note that the error function MUST NOT
+ * return to the calling routine or serious problems will occur.  The return
+ * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1)
+ */
+void PNGAPI
+png_set_error_fn(png_structrp png_ptr, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warning_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->error_ptr = error_ptr;
+   png_ptr->error_fn = error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
+   png_ptr->warning_fn = warning_fn;
+#else
+   PNG_UNUSED(warning_fn)
+#endif
+}
+
+
+/* This function returns a pointer to the error_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_error_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return NULL;
+
+   return (png_voidp)png_ptr->error_ptr;
+}
+
+
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+void PNGAPI
+png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode)
+{
+   if (png_ptr != NULL)
+   {
+      png_ptr->flags &=
+         ((~(PNG_FLAG_STRIP_ERROR_NUMBERS |
+         PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
+   }
+}
+#endif
+
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+   /* Currently the above both depend on SETJMP_SUPPORTED, however it would be
+    * possible to implement without setjmp support just so long as there is some
+    * way to handle the error return here:
+    */
+PNG_FUNCTION(void /* PRIVATE */, (PNGCBAPI
+png_safe_error),(png_structp png_nonconst_ptr, png_const_charp error_message),
+    PNG_NORETURN)
+{
+   png_const_structrp png_ptr = png_nonconst_ptr;
+   png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
+
+   /* An error is always logged here, overwriting anything (typically a warning)
+    * that is already there:
+    */
+   if (image != NULL)
+   {
+      png_safecat(image->message, (sizeof image->message), 0, error_message);
+      image->warning_or_error |= PNG_IMAGE_ERROR;
+
+      /* Retrieve the jmp_buf from within the png_control, making this work for
+       * C++ compilation too is pretty tricky: C++ wants a pointer to the first
+       * element of a jmp_buf, but C doesn't tell us the type of that.
+       */
+      if (image->opaque != NULL && image->opaque->error_buf != NULL)
+         longjmp(png_control_jmp_buf(image->opaque), 1);
+
+      /* Missing longjmp buffer, the following is to help debugging: */
+      {
+         size_t pos = png_safecat(image->message, (sizeof image->message), 0,
+             "bad longjmp: ");
+         png_safecat(image->message, (sizeof image->message), pos,
+             error_message);
+      }
+   }
+
+   /* Here on an internal programming error. */
+   abort();
+}
+
+#ifdef PNG_WARNINGS_SUPPORTED
+void /* PRIVATE */ PNGCBAPI
+png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message)
+{
+   png_const_structrp png_ptr = png_nonconst_ptr;
+   png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
+
+   /* A warning is only logged if there is no prior warning or error. */
+   if (image->warning_or_error == 0)
+   {
+      png_safecat(image->message, (sizeof image->message), 0, warning_message);
+      image->warning_or_error |= PNG_IMAGE_WARNING;
+   }
+}
+#endif
+
+int /* PRIVATE */
+png_safe_execute(png_imagep image, int (*function)(png_voidp), png_voidp arg)
+{
+   png_voidp saved_error_buf = image->opaque->error_buf;
+   jmp_buf safe_jmpbuf;
+   int result;
+
+   /* Safely execute function(arg), with png_error returning back here. */
+   if (setjmp(safe_jmpbuf) == 0)
+   {
+      image->opaque->error_buf = safe_jmpbuf;
+      result = function(arg);
+      image->opaque->error_buf = saved_error_buf;
+      return result;
+   }
+
+   /* On png_error, return via longjmp, pop the jmpbuf, and free the image. */
+   image->opaque->error_buf = saved_error_buf;
+   png_image_free(image);
+   return 0;
+}
+#endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */
+#endif /* READ || WRITE */
Index: /trunk/src/libs/libpng-1.6.45/pngget.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngget.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngget.c	(revision 107811)
@@ -0,0 +1,1267 @@
+
+/* pngget.c - retrieval of values from info struct
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+png_uint_32 PNGAPI
+png_get_valid(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 flag)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+#ifdef PNG_READ_tRNS_SUPPORTED
+      /* png_handle_PLTE() may have canceled a valid tRNS chunk but left the
+       * 'valid' flag for the detection of duplicate chunks. Do not report a
+       * valid tRNS chunk in this case.
+       */
+      if (flag == PNG_INFO_tRNS && png_ptr->num_trans == 0)
+         return 0;
+#endif
+
+      return info_ptr->valid & flag;
+   }
+
+   return 0;
+}
+
+size_t PNGAPI
+png_get_rowbytes(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->rowbytes;
+
+   return 0;
+}
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+png_bytepp PNGAPI
+png_get_rows(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->row_pointers;
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+/* Easy access to info, added in libpng-0.99 */
+png_uint_32 PNGAPI
+png_get_image_width(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->width;
+
+   return 0;
+}
+
+png_uint_32 PNGAPI
+png_get_image_height(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->height;
+
+   return 0;
+}
+
+png_byte PNGAPI
+png_get_bit_depth(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->bit_depth;
+
+   return 0;
+}
+
+png_byte PNGAPI
+png_get_color_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->color_type;
+
+   return 0;
+}
+
+png_byte PNGAPI
+png_get_filter_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->filter_type;
+
+   return 0;
+}
+
+png_byte PNGAPI
+png_get_interlace_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->interlace_type;
+
+   return 0;
+}
+
+png_byte PNGAPI
+png_get_compression_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->compression_type;
+
+   return 0;
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
+   info_ptr)
+{
+#ifdef PNG_pHYs_SUPPORTED
+   png_debug(1, "in png_get_x_pixels_per_meter");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
+         return info_ptr->x_pixels_per_unit;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return 0;
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
+    info_ptr)
+{
+#ifdef PNG_pHYs_SUPPORTED
+   png_debug(1, "in png_get_y_pixels_per_meter");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
+         return info_ptr->y_pixels_per_unit;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return 0;
+}
+
+png_uint_32 PNGAPI
+png_get_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_pHYs_SUPPORTED
+   png_debug(1, "in png_get_pixels_per_meter");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER &&
+          info_ptr->x_pixels_per_unit == info_ptr->y_pixels_per_unit)
+         return info_ptr->x_pixels_per_unit;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return 0;
+}
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_pixel_aspect_ratio(png_const_structrp png_ptr, png_const_inforp
+   info_ptr)
+{
+#ifdef PNG_READ_pHYs_SUPPORTED
+   png_debug(1, "in png_get_pixel_aspect_ratio");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      if (info_ptr->x_pixels_per_unit != 0)
+         return (float)info_ptr->y_pixels_per_unit
+              / (float)info_ptr->x_pixels_per_unit;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return (float)0.0;
+}
+#endif
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_fixed_point PNGAPI
+png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr,
+    png_const_inforp info_ptr)
+{
+#ifdef PNG_READ_pHYs_SUPPORTED
+   png_debug(1, "in png_get_pixel_aspect_ratio_fixed");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0 &&
+       info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0 &&
+       info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX &&
+       info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
+   {
+      png_fixed_point res;
+
+      /* The following casts work because a PNG 4 byte integer only has a valid
+       * range of 0..2^31-1; otherwise the cast might overflow.
+       */
+      if (png_muldiv(&res, (png_int_32)info_ptr->y_pixels_per_unit, PNG_FP_1,
+          (png_int_32)info_ptr->x_pixels_per_unit) != 0)
+         return res;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return 0;
+}
+#endif
+
+png_int_32 PNGAPI
+png_get_x_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+   png_debug(1, "in png_get_x_offset_microns");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
+         return info_ptr->x_offset;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return 0;
+}
+
+png_int_32 PNGAPI
+png_get_y_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+   png_debug(1, "in png_get_y_offset_microns");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
+         return info_ptr->y_offset;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return 0;
+}
+
+png_int_32 PNGAPI
+png_get_x_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+   png_debug(1, "in png_get_x_offset_pixels");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
+         return info_ptr->x_offset;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return 0;
+}
+
+png_int_32 PNGAPI
+png_get_y_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+   png_debug(1, "in png_get_y_offset_pixels");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
+         return info_ptr->y_offset;
+   }
+#else
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(info_ptr)
+#endif
+
+   return 0;
+}
+
+#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
+static png_uint_32
+ppi_from_ppm(png_uint_32 ppm)
+{
+#if 0
+   /* The conversion is *(2.54/100), in binary (32 digits):
+    * .00000110100000001001110101001001
+    */
+   png_uint_32 t1001, t1101;
+   ppm >>= 1;                  /* .1 */
+   t1001 = ppm + (ppm >> 3);   /* .1001 */
+   t1101 = t1001 + (ppm >> 1); /* .1101 */
+   ppm >>= 20;                 /* .000000000000000000001 */
+   t1101 += t1101 >> 15;       /* .1101000000000001101 */
+   t1001 >>= 11;               /* .000000000001001 */
+   t1001 += t1001 >> 12;       /* .000000000001001000000001001 */
+   ppm += t1001;               /* .000000000001001000001001001 */
+   ppm += t1101;               /* .110100000001001110101001001 */
+   return (ppm + 16) >> 5;/* .00000110100000001001110101001001 */
+#else
+   /* The argument is a PNG unsigned integer, so it is not permitted
+    * to be bigger than 2^31.
+    */
+   png_fixed_point result;
+   if (ppm <= PNG_UINT_31_MAX && png_muldiv(&result, (png_int_32)ppm, 127,
+       5000) != 0)
+      return (png_uint_32)result;
+
+   /* Overflow. */
+   return 0;
+#endif
+}
+
+png_uint_32 PNGAPI
+png_get_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   return ppi_from_ppm(png_get_pixels_per_meter(png_ptr, info_ptr));
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   return ppi_from_ppm(png_get_x_pixels_per_meter(png_ptr, info_ptr));
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   return ppi_from_ppm(png_get_y_pixels_per_meter(png_ptr, info_ptr));
+}
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+static png_fixed_point
+png_fixed_inches_from_microns(png_const_structrp png_ptr, png_int_32 microns)
+{
+   /* Convert from meters * 1,000,000 to inches * 100,000, meters to
+    * inches is simply *(100/2.54), so we want *(10/2.54) == 500/127.
+    * Notice that this can overflow - a warning is output and 0 is
+    * returned.
+    */
+   return png_muldiv_warn(png_ptr, microns, 500, 127);
+}
+
+png_fixed_point PNGAPI
+png_get_x_offset_inches_fixed(png_const_structrp png_ptr,
+    png_const_inforp info_ptr)
+{
+   return png_fixed_inches_from_microns(png_ptr,
+       png_get_x_offset_microns(png_ptr, info_ptr));
+}
+#endif
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_fixed_point PNGAPI
+png_get_y_offset_inches_fixed(png_const_structrp png_ptr,
+    png_const_inforp info_ptr)
+{
+   return png_fixed_inches_from_microns(png_ptr,
+       png_get_y_offset_microns(png_ptr, info_ptr));
+}
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_x_offset_inches(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   /* To avoid the overflow do the conversion directly in floating
+    * point.
+    */
+   return (float)(png_get_x_offset_microns(png_ptr, info_ptr) * .00003937);
+}
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_y_offset_inches(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   /* To avoid the overflow do the conversion directly in floating
+    * point.
+    */
+   return (float)(png_get_y_offset_microns(png_ptr, info_ptr) * .00003937);
+}
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+png_uint_32 PNGAPI
+png_get_pHYs_dpi(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
+{
+   png_uint_32 retval = 0;
+
+   png_debug1(1, "in %s retrieval function", "pHYs");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      if (res_x != NULL)
+      {
+         *res_x = info_ptr->x_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+
+      if (res_y != NULL)
+      {
+         *res_y = info_ptr->y_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+
+      if (unit_type != NULL)
+      {
+         *unit_type = (int)info_ptr->phys_unit_type;
+         retval |= PNG_INFO_pHYs;
+
+         if (*unit_type == 1)
+         {
+            if (res_x != NULL) *res_x = (png_uint_32)(*res_x * .0254 + .50);
+            if (res_y != NULL) *res_y = (png_uint_32)(*res_y * .0254 + .50);
+         }
+      }
+   }
+
+   return retval;
+}
+#endif /* pHYs */
+#endif /* INCH_CONVERSIONS */
+
+/* png_get_channels really belongs in here, too, but it's been around longer */
+
+#endif /* EASY_ACCESS */
+
+
+png_byte PNGAPI
+png_get_channels(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->channels;
+
+   return 0;
+}
+
+#ifdef PNG_READ_SUPPORTED
+png_const_bytep PNGAPI
+png_get_signature(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return info_ptr->signature;
+
+   return NULL;
+}
+#endif
+
+#ifdef PNG_bKGD_SUPPORTED
+png_uint_32 PNGAPI
+png_get_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_color_16p *background)
+{
+   png_debug1(1, "in %s retrieval function", "bKGD");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_bKGD) != 0 &&
+       background != NULL)
+   {
+      *background = &(info_ptr->background);
+      return PNG_INFO_bKGD;
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+/* The XYZ APIs were added in 1.5.5 to take advantage of the code added at the
+ * same time to correct the rgb grayscale coefficient defaults obtained from the
+ * cHRM chunk in 1.5.4
+ */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cHRM(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    double *white_x, double *white_y, double *red_x, double *red_y,
+    double *green_x, double *green_y, double *blue_x, double *blue_y)
+{
+   png_debug1(1, "in %s retrieval function", "cHRM");
+
+   /* Quiet API change: this code used to only return the end points if a cHRM
+    * chunk was present, but the end points can also come from iCCP or sRGB
+    * chunks, so in 1.6.0 the png_get_ APIs return the end points regardless and
+    * the png_set_ APIs merely check that set end points are mutually
+    * consistent.
+    */
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      if (white_x != NULL)
+         *white_x = png_float(png_ptr,
+             info_ptr->colorspace.end_points_xy.whitex, "cHRM white X");
+      if (white_y != NULL)
+         *white_y = png_float(png_ptr,
+             info_ptr->colorspace.end_points_xy.whitey, "cHRM white Y");
+      if (red_x != NULL)
+         *red_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redx,
+             "cHRM red X");
+      if (red_y != NULL)
+         *red_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redy,
+             "cHRM red Y");
+      if (green_x != NULL)
+         *green_x = png_float(png_ptr,
+             info_ptr->colorspace.end_points_xy.greenx, "cHRM green X");
+      if (green_y != NULL)
+         *green_y = png_float(png_ptr,
+             info_ptr->colorspace.end_points_xy.greeny, "cHRM green Y");
+      if (blue_x != NULL)
+         *blue_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluex,
+             "cHRM blue X");
+      if (blue_y != NULL)
+         *blue_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluey,
+             "cHRM blue Y");
+      return PNG_INFO_cHRM;
+   }
+
+   return 0;
+}
+
+png_uint_32 PNGAPI
+png_get_cHRM_XYZ(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    double *red_X, double *red_Y, double *red_Z, double *green_X,
+    double *green_Y, double *green_Z, double *blue_X, double *blue_Y,
+    double *blue_Z)
+{
+   png_debug1(1, "in %s retrieval function", "cHRM_XYZ(float)");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      if (red_X != NULL)
+         *red_X = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_X,
+             "cHRM red X");
+      if (red_Y != NULL)
+         *red_Y = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Y,
+             "cHRM red Y");
+      if (red_Z != NULL)
+         *red_Z = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Z,
+             "cHRM red Z");
+      if (green_X != NULL)
+         *green_X = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.green_X, "cHRM green X");
+      if (green_Y != NULL)
+         *green_Y = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.green_Y, "cHRM green Y");
+      if (green_Z != NULL)
+         *green_Z = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.green_Z, "cHRM green Z");
+      if (blue_X != NULL)
+         *blue_X = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.blue_X, "cHRM blue X");
+      if (blue_Y != NULL)
+         *blue_Y = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.blue_Y, "cHRM blue Y");
+      if (blue_Z != NULL)
+         *blue_Z = png_float(png_ptr,
+             info_ptr->colorspace.end_points_XYZ.blue_Z, "cHRM blue Z");
+      return PNG_INFO_cHRM;
+   }
+
+   return 0;
+}
+#  endif
+
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
+    png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
+    png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
+    png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
+    png_fixed_point *int_blue_Z)
+{
+   png_debug1(1, "in %s retrieval function", "cHRM_XYZ");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      if (int_red_X != NULL)
+         *int_red_X = info_ptr->colorspace.end_points_XYZ.red_X;
+      if (int_red_Y != NULL)
+         *int_red_Y = info_ptr->colorspace.end_points_XYZ.red_Y;
+      if (int_red_Z != NULL)
+         *int_red_Z = info_ptr->colorspace.end_points_XYZ.red_Z;
+      if (int_green_X != NULL)
+         *int_green_X = info_ptr->colorspace.end_points_XYZ.green_X;
+      if (int_green_Y != NULL)
+         *int_green_Y = info_ptr->colorspace.end_points_XYZ.green_Y;
+      if (int_green_Z != NULL)
+         *int_green_Z = info_ptr->colorspace.end_points_XYZ.green_Z;
+      if (int_blue_X != NULL)
+         *int_blue_X = info_ptr->colorspace.end_points_XYZ.blue_X;
+      if (int_blue_Y != NULL)
+         *int_blue_Y = info_ptr->colorspace.end_points_XYZ.blue_Y;
+      if (int_blue_Z != NULL)
+         *int_blue_Z = info_ptr->colorspace.end_points_XYZ.blue_Z;
+      return PNG_INFO_cHRM;
+   }
+
+   return 0;
+}
+
+png_uint_32 PNGAPI
+png_get_cHRM_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *white_x, png_fixed_point *white_y, png_fixed_point *red_x,
+    png_fixed_point *red_y, png_fixed_point *green_x, png_fixed_point *green_y,
+    png_fixed_point *blue_x, png_fixed_point *blue_y)
+{
+   png_debug1(1, "in %s retrieval function", "cHRM");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+   {
+      if (white_x != NULL)
+         *white_x = info_ptr->colorspace.end_points_xy.whitex;
+      if (white_y != NULL)
+         *white_y = info_ptr->colorspace.end_points_xy.whitey;
+      if (red_x != NULL)
+         *red_x = info_ptr->colorspace.end_points_xy.redx;
+      if (red_y != NULL)
+         *red_y = info_ptr->colorspace.end_points_xy.redy;
+      if (green_x != NULL)
+         *green_x = info_ptr->colorspace.end_points_xy.greenx;
+      if (green_y != NULL)
+         *green_y = info_ptr->colorspace.end_points_xy.greeny;
+      if (blue_x != NULL)
+         *blue_x = info_ptr->colorspace.end_points_xy.bluex;
+      if (blue_y != NULL)
+         *blue_y = info_ptr->colorspace.end_points_xy.bluey;
+      return PNG_INFO_cHRM;
+   }
+
+   return 0;
+}
+#  endif
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_gAMA_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_fixed_point *file_gamma)
+{
+   png_debug1(1, "in %s retrieval function", "gAMA");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+       file_gamma != NULL)
+   {
+      *file_gamma = info_ptr->colorspace.gamma;
+      return PNG_INFO_gAMA;
+   }
+
+   return 0;
+}
+#  endif
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_gAMA(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    double *file_gamma)
+{
+   png_debug1(1, "in %s retrieval function", "gAMA(float)");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+      file_gamma != NULL)
+   {
+      *file_gamma = png_float(png_ptr, info_ptr->colorspace.gamma,
+          "png_get_gAMA");
+      return PNG_INFO_gAMA;
+   }
+
+   return 0;
+}
+#  endif
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sRGB(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    int *file_srgb_intent)
+{
+   png_debug1(1, "in %s retrieval function", "sRGB");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->valid & PNG_INFO_sRGB) != 0 && file_srgb_intent != NULL)
+   {
+      *file_srgb_intent = info_ptr->colorspace.rendering_intent;
+      return PNG_INFO_sRGB;
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+png_uint_32 PNGAPI
+png_get_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_charpp name, int *compression_type,
+    png_bytepp profile, png_uint_32 *proflen)
+{
+   png_debug1(1, "in %s retrieval function", "iCCP");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_iCCP) != 0 &&
+       name != NULL && profile != NULL && proflen != NULL)
+   {
+      *name = info_ptr->iccp_name;
+      *profile = info_ptr->iccp_profile;
+      *proflen = png_get_uint_32(info_ptr->iccp_profile);
+      /* This is somewhat irrelevant since the profile data returned has
+       * actually been uncompressed.
+       */
+      if (compression_type != NULL)
+         *compression_type = PNG_COMPRESSION_TYPE_BASE;
+      return PNG_INFO_iCCP;
+   }
+
+   return 0;
+
+}
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+int PNGAPI
+png_get_sPLT(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_sPLT_tpp spalettes)
+{
+   png_debug1(1, "in %s retrieval function", "sPLT");
+
+   if (png_ptr != NULL && info_ptr != NULL && spalettes != NULL)
+   {
+      *spalettes = info_ptr->splt_palettes;
+      return info_ptr->splt_palettes_num;
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_eXIf_SUPPORTED
+png_uint_32 PNGAPI
+png_get_eXIf(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_bytep *exif)
+{
+  png_warning(png_ptr, "png_get_eXIf does not work; use png_get_eXIf_1");
+  PNG_UNUSED(info_ptr)
+  PNG_UNUSED(exif)
+  return 0;
+}
+
+png_uint_32 PNGAPI
+png_get_eXIf_1(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 *num_exif, png_bytep *exif)
+{
+   png_debug1(1, "in %s retrieval function", "eXIf");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_eXIf) != 0 && exif != NULL)
+   {
+      *num_exif = info_ptr->num_exif;
+      *exif = info_ptr->exif;
+      return PNG_INFO_eXIf;
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+png_uint_32 PNGAPI
+png_get_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_uint_16p *hist)
+{
+   png_debug1(1, "in %s retrieval function", "hIST");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_hIST) != 0 && hist != NULL)
+   {
+      *hist = info_ptr->hist;
+      return PNG_INFO_hIST;
+   }
+
+   return 0;
+}
+#endif
+
+png_uint_32 PNGAPI
+png_get_IHDR(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 *width, png_uint_32 *height, int *bit_depth,
+    int *color_type, int *interlace_type, int *compression_type,
+    int *filter_type)
+{
+   png_debug1(1, "in %s retrieval function", "IHDR");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return 0;
+
+   if (width != NULL)
+       *width = info_ptr->width;
+
+   if (height != NULL)
+       *height = info_ptr->height;
+
+   if (bit_depth != NULL)
+       *bit_depth = info_ptr->bit_depth;
+
+   if (color_type != NULL)
+       *color_type = info_ptr->color_type;
+
+   if (compression_type != NULL)
+      *compression_type = info_ptr->compression_type;
+
+   if (filter_type != NULL)
+      *filter_type = info_ptr->filter_type;
+
+   if (interlace_type != NULL)
+      *interlace_type = info_ptr->interlace_type;
+
+   /* This is redundant if we can be sure that the info_ptr values were all
+    * assigned in png_set_IHDR().  We do the check anyhow in case an
+    * application has ignored our advice not to mess with the members
+    * of info_ptr directly.
+    */
+   png_check_IHDR(png_ptr, info_ptr->width, info_ptr->height,
+       info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
+       info_ptr->compression_type, info_ptr->filter_type);
+
+   return 1;
+}
+
+#ifdef PNG_oFFs_SUPPORTED
+png_uint_32 PNGAPI
+png_get_oFFs(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type)
+{
+   png_debug1(1, "in %s retrieval function", "oFFs");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_oFFs) != 0 &&
+       offset_x != NULL && offset_y != NULL && unit_type != NULL)
+   {
+      *offset_x = info_ptr->x_offset;
+      *offset_y = info_ptr->y_offset;
+      *unit_type = (int)info_ptr->offset_unit_type;
+      return PNG_INFO_oFFs;
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+png_uint_32 PNGAPI
+png_get_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type, int *nparams,
+    png_charp *units, png_charpp *params)
+{
+   png_debug1(1, "in %s retrieval function", "pCAL");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pCAL) != 0 &&
+       purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+       nparams != NULL && units != NULL && params != NULL)
+   {
+      *purpose = info_ptr->pcal_purpose;
+      *X0 = info_ptr->pcal_X0;
+      *X1 = info_ptr->pcal_X1;
+      *type = (int)info_ptr->pcal_type;
+      *nparams = (int)info_ptr->pcal_nparams;
+      *units = info_ptr->pcal_units;
+      *params = info_ptr->pcal_params;
+      return PNG_INFO_pCAL;
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+#    if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+         defined(PNG_FLOATING_POINT_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    int *unit, png_fixed_point *width, png_fixed_point *height)
+{
+   png_debug1(1, "in %s retrieval function", "sCAL");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
+   {
+      *unit = info_ptr->scal_unit;
+      /*TODO: make this work without FP support; the API is currently eliminated
+       * if neither floating point APIs nor internal floating point arithmetic
+       * are enabled.
+       */
+      *width = png_fixed(png_ptr, atof(info_ptr->scal_s_width), "sCAL width");
+      *height = png_fixed(png_ptr, atof(info_ptr->scal_s_height),
+          "sCAL height");
+      return PNG_INFO_sCAL;
+   }
+
+   return 0;
+}
+#    endif /* FLOATING_ARITHMETIC */
+#  endif /* FIXED_POINT */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    int *unit, double *width, double *height)
+{
+   png_debug1(1, "in %s retrieval function", "sCAL(float)");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
+   {
+      *unit = info_ptr->scal_unit;
+      *width = atof(info_ptr->scal_s_width);
+      *height = atof(info_ptr->scal_s_height);
+      return PNG_INFO_sCAL;
+   }
+
+   return 0;
+}
+#  endif /* FLOATING POINT */
+png_uint_32 PNGAPI
+png_get_sCAL_s(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    int *unit, png_charpp width, png_charpp height)
+{
+   png_debug1(1, "in %s retrieval function", "sCAL(str)");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL) != 0)
+   {
+      *unit = info_ptr->scal_unit;
+      *width = info_ptr->scal_s_width;
+      *height = info_ptr->scal_s_height;
+      return PNG_INFO_sCAL;
+   }
+
+   return 0;
+}
+#endif /* sCAL */
+
+#ifdef PNG_pHYs_SUPPORTED
+png_uint_32 PNGAPI
+png_get_pHYs(png_const_structrp png_ptr, png_const_inforp info_ptr,
+    png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
+{
+   png_uint_32 retval = 0;
+
+   png_debug1(1, "in %s retrieval function", "pHYs");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      if (res_x != NULL)
+      {
+         *res_x = info_ptr->x_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+
+      if (res_y != NULL)
+      {
+         *res_y = info_ptr->y_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+
+      if (unit_type != NULL)
+      {
+         *unit_type = (int)info_ptr->phys_unit_type;
+         retval |= PNG_INFO_pHYs;
+      }
+   }
+
+   return retval;
+}
+#endif /* pHYs */
+
+png_uint_32 PNGAPI
+png_get_PLTE(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_colorp *palette, int *num_palette)
+{
+   png_debug1(1, "in %s retrieval function", "PLTE");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_PLTE) != 0 && palette != NULL)
+   {
+      *palette = info_ptr->palette;
+      *num_palette = info_ptr->num_palette;
+      png_debug1(3, "num_palette = %d", *num_palette);
+      return PNG_INFO_PLTE;
+   }
+
+   return 0;
+}
+
+#ifdef PNG_sBIT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_color_8p *sig_bit)
+{
+   png_debug1(1, "in %s retrieval function", "sBIT");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sBIT) != 0 && sig_bit != NULL)
+   {
+      *sig_bit = &(info_ptr->sig_bit);
+      return PNG_INFO_sBIT;
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+int PNGAPI
+png_get_text(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_textp *text_ptr, int *num_text)
+{
+   if (png_ptr != NULL && info_ptr != NULL && info_ptr->num_text > 0)
+   {
+      png_debug1(1, "in text retrieval function, chunk typeid = 0x%lx",
+         (unsigned long)png_ptr->chunk_name);
+
+      if (text_ptr != NULL)
+         *text_ptr = info_ptr->text;
+
+      if (num_text != NULL)
+         *num_text = info_ptr->num_text;
+
+      return info_ptr->num_text;
+   }
+
+   if (num_text != NULL)
+      *num_text = 0;
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+png_uint_32 PNGAPI
+png_get_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_timep *mod_time)
+{
+   png_debug1(1, "in %s retrieval function", "tIME");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tIME) != 0 && mod_time != NULL)
+   {
+      *mod_time = &(info_ptr->mod_time);
+      return PNG_INFO_tIME;
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+png_uint_32 PNGAPI
+png_get_tRNS(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color)
+{
+   png_uint_32 retval = 0;
+
+   png_debug1(1, "in %s retrieval function", "tRNS");
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_tRNS) != 0)
+   {
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         if (trans_alpha != NULL)
+         {
+            *trans_alpha = info_ptr->trans_alpha;
+            retval |= PNG_INFO_tRNS;
+         }
+
+         if (trans_color != NULL)
+            *trans_color = &(info_ptr->trans_color);
+      }
+
+      else /* if (info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) */
+      {
+         if (trans_color != NULL)
+         {
+            *trans_color = &(info_ptr->trans_color);
+            retval |= PNG_INFO_tRNS;
+         }
+
+         if (trans_alpha != NULL)
+            *trans_alpha = NULL;
+      }
+
+      if (num_trans != NULL)
+      {
+         *num_trans = info_ptr->num_trans;
+         retval |= PNG_INFO_tRNS;
+      }
+   }
+
+   return retval;
+}
+#endif
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+int PNGAPI
+png_get_unknown_chunks(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_unknown_chunkpp unknowns)
+{
+   if (png_ptr != NULL && info_ptr != NULL && unknowns != NULL)
+   {
+      *unknowns = info_ptr->unknown_chunks;
+      return info_ptr->unknown_chunks_num;
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+png_byte PNGAPI
+png_get_rgb_to_gray_status(png_const_structrp png_ptr)
+{
+   return (png_byte)(png_ptr ? png_ptr->rgb_to_gray_status : 0);
+}
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+png_voidp PNGAPI
+png_get_user_chunk_ptr(png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_chunk_ptr : NULL);
+}
+#endif
+
+size_t PNGAPI
+png_get_compression_buffer_size(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return 0;
+
+#ifdef PNG_WRITE_SUPPORTED
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+#endif
+   {
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+      return png_ptr->IDAT_read_size;
+#else
+      return PNG_IDAT_READ_SIZE;
+#endif
+   }
+
+#ifdef PNG_WRITE_SUPPORTED
+   else
+      return png_ptr->zbuffer_size;
+#endif
+}
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+/* These functions were added to libpng 1.2.6 and were enabled
+ * by default in libpng-1.4.0 */
+png_uint_32 PNGAPI
+png_get_user_width_max(png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_width_max : 0);
+}
+
+png_uint_32 PNGAPI
+png_get_user_height_max(png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_height_max : 0);
+}
+
+/* This function was added to libpng 1.4.0 */
+png_uint_32 PNGAPI
+png_get_chunk_cache_max(png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_chunk_cache_max : 0);
+}
+
+/* This function was added to libpng 1.4.1 */
+png_alloc_size_t PNGAPI
+png_get_chunk_malloc_max(png_const_structrp png_ptr)
+{
+   return (png_ptr ? png_ptr->user_chunk_malloc_max : 0);
+}
+#endif /* SET_USER_LIMITS */
+
+/* These functions were added to libpng 1.4.0 */
+#ifdef PNG_IO_STATE_SUPPORTED
+png_uint_32 PNGAPI
+png_get_io_state(png_const_structrp png_ptr)
+{
+   return png_ptr->io_state;
+}
+
+png_uint_32 PNGAPI
+png_get_io_chunk_type(png_const_structrp png_ptr)
+{
+   return png_ptr->chunk_name;
+}
+#endif /* IO_STATE */
+
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+int PNGAPI
+png_get_palette_max(png_const_structp png_ptr, png_const_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return png_ptr->num_palette_max;
+
+   return -1;
+}
+#  endif
+#endif
+
+#endif /* READ || WRITE */
Index: /trunk/src/libs/libpng-1.6.45/pnginfo.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pnginfo.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pnginfo.h	(revision 107811)
@@ -0,0 +1,267 @@
+
+/* pnginfo.h - header file for PNG reference library
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2013,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+ /* png_info is a structure that holds the information in a PNG file so
+ * that the application can find out the characteristics of the image.
+ * If you are reading the file, this structure will tell you what is
+ * in the PNG file.  If you are writing the file, fill in the information
+ * you want to put into the PNG file, using png_set_*() functions, then
+ * call png_write_info().
+ *
+ * The names chosen should be very close to the PNG specification, so
+ * consult that document for information about the meaning of each field.
+ *
+ * With libpng < 0.95, it was only possible to directly set and read the
+ * the values in the png_info_struct, which meant that the contents and
+ * order of the values had to remain fixed.  With libpng 0.95 and later,
+ * however, there are now functions that abstract the contents of
+ * png_info_struct from the application, so this makes it easier to use
+ * libpng with dynamic libraries, and even makes it possible to use
+ * libraries that don't have all of the libpng ancillary chunk-handing
+ * functionality.  In libpng-1.5.0 this was moved into a separate private
+ * file that is not visible to applications.
+ *
+ * The following members may have allocated storage attached that should be
+ * cleaned up before the structure is discarded: palette, trans, text,
+ * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
+ * splt_palettes, scal_unit, row_pointers, and unknowns.   By default, these
+ * are automatically freed when the info structure is deallocated, if they were
+ * allocated internally by libpng.  This behavior can be changed by means
+ * of the png_data_freer() function.
+ *
+ * More allocation details: all the chunk-reading functions that
+ * change these members go through the corresponding png_set_*
+ * functions.  A function to clear these members is available: see
+ * png_free_data().  The png_set_* functions do not depend on being
+ * able to point info structure members to any of the storage they are
+ * passed (they make their own copies), EXCEPT that the png_set_text
+ * functions use the same storage passed to them in the text_ptr or
+ * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
+ * functions do not make their own copies.
+ */
+#ifndef PNGINFO_H
+#define PNGINFO_H
+
+struct png_info_def
+{
+   /* The following are necessary for every PNG file */
+   png_uint_32 width;       /* width of image in pixels (from IHDR) */
+   png_uint_32 height;      /* height of image in pixels (from IHDR) */
+   png_uint_32 valid;       /* valid chunk data (see PNG_INFO_ below) */
+   size_t rowbytes;         /* bytes needed to hold an untransformed row */
+   png_colorp palette;      /* array of color values (valid & PNG_INFO_PLTE) */
+   png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
+   png_uint_16 num_trans;   /* number of transparent palette color (tRNS) */
+   png_byte bit_depth;      /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
+   png_byte color_type;     /* see PNG_COLOR_TYPE_ below (from IHDR) */
+   /* The following three should have been named *_method not *_type */
+   png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
+   png_byte filter_type;    /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
+   png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
+
+   /* The following are set by png_set_IHDR, called from the application on
+    * write, but the are never actually used by the write code.
+    */
+   png_byte channels;       /* number of data channels per pixel (1, 2, 3, 4) */
+   png_byte pixel_depth;    /* number of bits per pixel */
+   png_byte spare_byte;     /* to align the data, and for future use */
+
+#ifdef PNG_READ_SUPPORTED
+   /* This is never set during write */
+   png_byte signature[8];   /* magic bytes read by libpng from start of file */
+#endif
+
+   /* The rest of the data is optional.  If you are reading, check the
+    * valid field to see if the information in these are valid.  If you
+    * are writing, set the valid field to those chunks you want written,
+    * and initialize the appropriate fields below.
+    */
+
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+   /* png_colorspace only contains 'flags' if neither GAMMA or COLORSPACE are
+    * defined.  When COLORSPACE is switched on all the colorspace-defining
+    * chunks should be enabled, when GAMMA is switched on all the gamma-defining
+    * chunks should be enabled.  If this is not done it becomes possible to read
+    * inconsistent PNG files and assign a probably incorrect interpretation to
+    * the information.  (In other words, by carefully choosing which chunks to
+    * recognize the system configuration can select an interpretation for PNG
+    * files containing ambiguous data and this will result in inconsistent
+    * behavior between different libpng builds!)
+    */
+   png_colorspace colorspace;
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+   /* iCCP chunk data. */
+   png_charp iccp_name;     /* profile name */
+   png_bytep iccp_profile;  /* International Color Consortium profile data */
+   png_uint_32 iccp_proflen;  /* ICC profile data length */
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+   /* The tEXt, and zTXt chunks contain human-readable textual data in
+    * uncompressed, compressed, and optionally compressed forms, respectively.
+    * The data in "text" is an array of pointers to uncompressed,
+    * null-terminated C strings. Each chunk has a keyword that describes the
+    * textual data contained in that chunk.  Keywords are not required to be
+    * unique, and the text string may be empty.  Any number of text chunks may
+    * be in an image.
+    */
+   int num_text; /* number of comments read or comments to write */
+   int max_text; /* current size of text array */
+   png_textp text; /* array of comments read or comments to write */
+#endif /* TEXT */
+
+#ifdef PNG_tIME_SUPPORTED
+   /* The tIME chunk holds the last time the displayed image data was
+    * modified.  See the png_time struct for the contents of this struct.
+    */
+   png_time mod_time;
+#endif
+
+#ifdef PNG_sBIT_SUPPORTED
+   /* The sBIT chunk specifies the number of significant high-order bits
+    * in the pixel data.  Values are in the range [1, bit_depth], and are
+    * only specified for the channels in the pixel data.  The contents of
+    * the low-order bits is not specified.  Data is valid if
+    * (valid & PNG_INFO_sBIT) is non-zero.
+    */
+   png_color_8 sig_bit; /* significant bits in color channels */
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
+defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* The tRNS chunk supplies transparency data for paletted images and
+    * other image types that don't need a full alpha channel.  There are
+    * "num_trans" transparency values for a paletted image, stored in the
+    * same order as the palette colors, starting from index 0.  Values
+    * for the data are in the range [0, 255], ranging from fully transparent
+    * to fully opaque, respectively.  For non-paletted images, there is a
+    * single color specified that should be treated as fully transparent.
+    * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
+    */
+   png_bytep trans_alpha;    /* alpha values for paletted image */
+   png_color_16 trans_color; /* transparent color for non-palette image */
+#endif
+
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* The bKGD chunk gives the suggested image background color if the
+    * display program does not have its own background color and the image
+    * is needs to composited onto a background before display.  The colors
+    * in "background" are normally in the same color space/depth as the
+    * pixel data.  Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
+    */
+   png_color_16 background;
+#endif
+
+#ifdef PNG_oFFs_SUPPORTED
+   /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
+    * and downwards from the top-left corner of the display, page, or other
+    * application-specific co-ordinate space.  See the PNG_OFFSET_ defines
+    * below for the unit types.  Valid if (valid & PNG_INFO_oFFs) non-zero.
+    */
+   png_int_32 x_offset; /* x offset on page */
+   png_int_32 y_offset; /* y offset on page */
+   png_byte offset_unit_type; /* offset units type */
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+   /* The pHYs chunk gives the physical pixel density of the image for
+    * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
+    * defines below).  Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
+    */
+   png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
+   png_uint_32 y_pixels_per_unit; /* vertical pixel density */
+   png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
+#endif
+
+#ifdef PNG_eXIf_SUPPORTED
+   int num_exif;  /* Added at libpng-1.6.31 */
+   png_bytep exif;
+# ifdef PNG_READ_eXIf_SUPPORTED
+   png_bytep eXIf_buf;  /* Added at libpng-1.6.32 */
+# endif
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+   /* The hIST chunk contains the relative frequency or importance of the
+    * various palette entries, so that a viewer can intelligently select a
+    * reduced-color palette, if required.  Data is an array of "num_palette"
+    * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
+    * is non-zero.
+    */
+   png_uint_16p hist;
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+   /* The pCAL chunk describes a transformation between the stored pixel
+    * values and original physical data values used to create the image.
+    * The integer range [0, 2^bit_depth - 1] maps to the floating-point
+    * range given by [pcal_X0, pcal_X1], and are further transformed by a
+    * (possibly non-linear) transformation function given by "pcal_type"
+    * and "pcal_params" into "pcal_units".  Please see the PNG_EQUATION_
+    * defines below, and the PNG-Group's PNG extensions document for a
+    * complete description of the transformations and how they should be
+    * implemented, and for a description of the ASCII parameter strings.
+    * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
+    */
+   png_charp pcal_purpose;  /* pCAL chunk description string */
+   png_int_32 pcal_X0;      /* minimum value */
+   png_int_32 pcal_X1;      /* maximum value */
+   png_charp pcal_units;    /* Latin-1 string giving physical units */
+   png_charpp pcal_params;  /* ASCII strings containing parameter values */
+   png_byte pcal_type;      /* equation type (see PNG_EQUATION_ below) */
+   png_byte pcal_nparams;   /* number of parameters given in pcal_params */
+#endif
+
+/* New members added in libpng-1.0.6 */
+   png_uint_32 free_me;     /* flags items libpng is responsible for freeing */
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+   /* Storage for unknown chunks that the library doesn't recognize. */
+   png_unknown_chunkp unknown_chunks;
+
+   /* The type of this field is limited by the type of
+    * png_struct::user_chunk_cache_max, else overflow can occur.
+    */
+   int                unknown_chunks_num;
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+   /* Data on sPLT chunks (there may be more than one). */
+   png_sPLT_tp splt_palettes;
+   int         splt_palettes_num; /* Match type returned by png_get API */
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+   /* The sCAL chunk describes the actual physical dimensions of the
+    * subject matter of the graphic.  The chunk contains a unit specification
+    * a byte value, and two ASCII strings representing floating-point
+    * values.  The values are width and height corresponding to one pixel
+    * in the image.  Data values are valid if (valid & PNG_INFO_sCAL) is
+    * non-zero.
+    */
+   png_byte scal_unit;         /* unit of physical scale */
+   png_charp scal_s_width;     /* string containing height */
+   png_charp scal_s_height;    /* string containing width */
+#endif
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+   /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS)
+      non-zero */
+   /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
+   png_bytepp row_pointers;        /* the image bits */
+#endif
+
+};
+#endif /* PNGINFO_H */
Index: /trunk/src/libs/libpng-1.6.45/pnglibconf.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pnglibconf.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pnglibconf.h	(revision 107811)
@@ -0,0 +1,219 @@
+/* pnglibconf.h - library build configuration */
+
+/* libpng version 1.6.37 */
+
+/* Copyright (c) 2018 Cosmin Truta */
+/* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson */
+
+/* This code is released under the libpng license. */
+/* For conditions of distribution and use, see the disclaimer */
+/* and license in png.h */
+
+/* pnglibconf.h */
+/* Machine generated file: DO NOT EDIT */
+/* Derived from: scripts/pnglibconf.dfa */
+#ifndef PNGLCONF_H
+#define PNGLCONF_H
+/* options */
+#define PNG_16BIT_SUPPORTED
+#define PNG_ALIGNED_MEMORY_SUPPORTED
+/*#undef PNG_ARM_NEON_API_SUPPORTED*/
+/*#undef PNG_ARM_NEON_CHECK_SUPPORTED*/
+#define PNG_BENIGN_ERRORS_SUPPORTED
+#define PNG_BENIGN_READ_ERRORS_SUPPORTED
+/*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/
+#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+#define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_COLORSPACE_SUPPORTED
+#define PNG_CONSOLE_IO_SUPPORTED
+#define PNG_CONVERT_tIME_SUPPORTED
+#define PNG_EASY_ACCESS_SUPPORTED
+/*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
+#define PNG_ERROR_TEXT_SUPPORTED
+#define PNG_FIXED_POINT_SUPPORTED
+#define PNG_FLOATING_ARITHMETIC_SUPPORTED
+#define PNG_FLOATING_POINT_SUPPORTED
+#define PNG_FORMAT_AFIRST_SUPPORTED
+#define PNG_FORMAT_BGR_SUPPORTED
+#define PNG_GAMMA_SUPPORTED
+#define PNG_GET_PALETTE_MAX_SUPPORTED
+#define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#define PNG_INCH_CONVERSIONS_SUPPORTED
+#define PNG_INFO_IMAGE_SUPPORTED
+#define PNG_IO_STATE_SUPPORTED
+#define PNG_MNG_FEATURES_SUPPORTED
+#define PNG_POINTER_INDEXING_SUPPORTED
+/*#undef PNG_POWERPC_VSX_API_SUPPORTED*/
+/*#undef PNG_POWERPC_VSX_CHECK_SUPPORTED*/
+#define PNG_PROGRESSIVE_READ_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+#define PNG_READ_ALPHA_MODE_SUPPORTED
+#define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
+#define PNG_READ_BACKGROUND_SUPPORTED
+#define PNG_READ_BGR_SUPPORTED
+#define PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_READ_COMPOSITE_NODIV_SUPPORTED
+#define PNG_READ_COMPRESSED_TEXT_SUPPORTED
+#define PNG_READ_EXPAND_16_SUPPORTED
+#define PNG_READ_EXPAND_SUPPORTED
+#define PNG_READ_FILLER_SUPPORTED
+#define PNG_READ_GAMMA_SUPPORTED
+#define PNG_READ_GET_PALETTE_MAX_SUPPORTED
+#define PNG_READ_GRAY_TO_RGB_SUPPORTED
+#define PNG_READ_INTERLACING_SUPPORTED
+#define PNG_READ_INT_FUNCTIONS_SUPPORTED
+#define PNG_READ_INVERT_ALPHA_SUPPORTED
+#define PNG_READ_INVERT_SUPPORTED
+#define PNG_READ_OPT_PLTE_SUPPORTED
+#define PNG_READ_PACKSWAP_SUPPORTED
+#define PNG_READ_PACK_SUPPORTED
+#define PNG_READ_QUANTIZE_SUPPORTED
+#define PNG_READ_RGB_TO_GRAY_SUPPORTED
+#define PNG_READ_SCALE_16_TO_8_SUPPORTED
+#define PNG_READ_SHIFT_SUPPORTED
+#define PNG_READ_STRIP_16_TO_8_SUPPORTED
+#define PNG_READ_STRIP_ALPHA_SUPPORTED
+#define PNG_READ_SUPPORTED
+#define PNG_READ_SWAP_ALPHA_SUPPORTED
+#define PNG_READ_SWAP_SUPPORTED
+#define PNG_READ_TEXT_SUPPORTED
+#define PNG_READ_TRANSFORMS_SUPPORTED
+#define PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_READ_USER_CHUNKS_SUPPORTED
+#define PNG_READ_USER_TRANSFORM_SUPPORTED
+#define PNG_READ_bKGD_SUPPORTED
+#define PNG_READ_cHRM_SUPPORTED
+#define PNG_READ_eXIf_SUPPORTED
+#define PNG_READ_gAMA_SUPPORTED
+#define PNG_READ_hIST_SUPPORTED
+#define PNG_READ_iCCP_SUPPORTED
+#define PNG_READ_iTXt_SUPPORTED
+#define PNG_READ_oFFs_SUPPORTED
+#define PNG_READ_pCAL_SUPPORTED
+#define PNG_READ_pHYs_SUPPORTED
+#define PNG_READ_sBIT_SUPPORTED
+#define PNG_READ_sCAL_SUPPORTED
+#define PNG_READ_sPLT_SUPPORTED
+#define PNG_READ_sRGB_SUPPORTED
+#define PNG_READ_tEXt_SUPPORTED
+#define PNG_READ_tIME_SUPPORTED
+#define PNG_READ_tRNS_SUPPORTED
+#define PNG_READ_zTXt_SUPPORTED
+#define PNG_SAVE_INT_32_SUPPORTED
+#define PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_SEQUENTIAL_READ_SUPPORTED
+#define PNG_SETJMP_SUPPORTED
+#define PNG_SET_OPTION_SUPPORTED
+#define PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_SET_USER_LIMITS_SUPPORTED
+#define PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
+#define PNG_SIMPLIFIED_READ_BGR_SUPPORTED
+#define PNG_SIMPLIFIED_READ_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_SUPPORTED
+#define PNG_STDIO_SUPPORTED
+#define PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_TEXT_SUPPORTED
+#define PNG_TIME_RFC1123_SUPPORTED
+#define PNG_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_USER_CHUNKS_SUPPORTED
+#define PNG_USER_LIMITS_SUPPORTED
+#define PNG_USER_MEM_SUPPORTED
+#define PNG_USER_TRANSFORM_INFO_SUPPORTED
+#define PNG_USER_TRANSFORM_PTR_SUPPORTED
+#define PNG_WARNINGS_SUPPORTED
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED
+#define PNG_WRITE_BGR_SUPPORTED
+#define PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#define PNG_WRITE_FILLER_SUPPORTED
+#define PNG_WRITE_FILTER_SUPPORTED
+#define PNG_WRITE_FLUSH_SUPPORTED
+#define PNG_WRITE_GET_PALETTE_MAX_SUPPORTED
+#define PNG_WRITE_INTERLACING_SUPPORTED
+#define PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+#define PNG_WRITE_INVERT_ALPHA_SUPPORTED
+#define PNG_WRITE_INVERT_SUPPORTED
+#define PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+#define PNG_WRITE_PACKSWAP_SUPPORTED
+#define PNG_WRITE_PACK_SUPPORTED
+#define PNG_WRITE_SHIFT_SUPPORTED
+#define PNG_WRITE_SUPPORTED
+#define PNG_WRITE_SWAP_ALPHA_SUPPORTED
+#define PNG_WRITE_SWAP_SUPPORTED
+#define PNG_WRITE_TEXT_SUPPORTED
+#define PNG_WRITE_TRANSFORMS_SUPPORTED
+#define PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_WRITE_USER_TRANSFORM_SUPPORTED
+#define PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+#define PNG_WRITE_bKGD_SUPPORTED
+#define PNG_WRITE_cHRM_SUPPORTED
+#define PNG_WRITE_eXIf_SUPPORTED
+#define PNG_WRITE_gAMA_SUPPORTED
+#define PNG_WRITE_hIST_SUPPORTED
+#define PNG_WRITE_iCCP_SUPPORTED
+#define PNG_WRITE_iTXt_SUPPORTED
+#define PNG_WRITE_oFFs_SUPPORTED
+#define PNG_WRITE_pCAL_SUPPORTED
+#define PNG_WRITE_pHYs_SUPPORTED
+#define PNG_WRITE_sBIT_SUPPORTED
+#define PNG_WRITE_sCAL_SUPPORTED
+#define PNG_WRITE_sPLT_SUPPORTED
+#define PNG_WRITE_sRGB_SUPPORTED
+#define PNG_WRITE_tEXt_SUPPORTED
+#define PNG_WRITE_tIME_SUPPORTED
+#define PNG_WRITE_tRNS_SUPPORTED
+#define PNG_WRITE_zTXt_SUPPORTED
+#define PNG_bKGD_SUPPORTED
+#define PNG_cHRM_SUPPORTED
+#define PNG_eXIf_SUPPORTED
+#define PNG_gAMA_SUPPORTED
+#define PNG_hIST_SUPPORTED
+#define PNG_iCCP_SUPPORTED
+#define PNG_iTXt_SUPPORTED
+#define PNG_oFFs_SUPPORTED
+#define PNG_pCAL_SUPPORTED
+#define PNG_pHYs_SUPPORTED
+#define PNG_sBIT_SUPPORTED
+#define PNG_sCAL_SUPPORTED
+#define PNG_sPLT_SUPPORTED
+#define PNG_sRGB_SUPPORTED
+#define PNG_tEXt_SUPPORTED
+#define PNG_tIME_SUPPORTED
+#define PNG_tRNS_SUPPORTED
+#define PNG_zTXt_SUPPORTED
+/* end of options */
+/* settings */
+#define PNG_API_RULE 0
+#define PNG_DEFAULT_READ_MACROS 1
+#define PNG_GAMMA_THRESHOLD_FIXED 5000
+#define PNG_IDAT_READ_SIZE PNG_ZBUF_SIZE
+#define PNG_INFLATE_BUF_SIZE 1024
+#define PNG_LINKAGE_API extern
+#define PNG_LINKAGE_CALLBACK extern
+#define PNG_LINKAGE_DATA extern
+#define PNG_LINKAGE_FUNCTION extern
+#define PNG_MAX_GAMMA_8 11
+#define PNG_QUANTIZE_BLUE_BITS 5
+#define PNG_QUANTIZE_GREEN_BITS 5
+#define PNG_QUANTIZE_RED_BITS 5
+#define PNG_TEXT_Z_DEFAULT_COMPRESSION (-1)
+#define PNG_TEXT_Z_DEFAULT_STRATEGY 0
+#define PNG_USER_CHUNK_CACHE_MAX 1000
+#define PNG_USER_CHUNK_MALLOC_MAX 8000000
+#define PNG_USER_HEIGHT_MAX 1000000
+#define PNG_USER_WIDTH_MAX 1000000
+#define PNG_ZBUF_SIZE 8192
+#define PNG_ZLIB_VERNUM 0 /* unknown */
+#define PNG_Z_DEFAULT_COMPRESSION (-1)
+#define PNG_Z_DEFAULT_NOFILTER_STRATEGY 0
+#define PNG_Z_DEFAULT_STRATEGY 1
+#define PNG_sCAL_PRECISION 5
+#define PNG_sRGB_PROFILE_CHECKS 2
+/* end of settings */
+#endif /* PNGLCONF_H */
Index: /trunk/src/libs/libpng-1.6.45/pngmem.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngmem.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngmem.c	(revision 107811)
@@ -0,0 +1,284 @@
+
+/* pngmem.c - stub functions for memory allocation
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2014,2016 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all memory allocation.  Users who
+ * need special memory handling are expected to supply replacement
+ * functions for png_malloc() and png_free(), and to use
+ * png_create_read_struct_2() and png_create_write_struct_2() to
+ * identify the replacement functions.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Free a png_struct */
+void /* PRIVATE */
+png_destroy_png_struct(png_structrp png_ptr)
+{
+   if (png_ptr != NULL)
+   {
+      /* png_free might call png_error and may certainly call
+       * png_get_mem_ptr, so fake a temporary png_struct to support this.
+       */
+      png_struct dummy_struct = *png_ptr;
+      memset(png_ptr, 0, (sizeof *png_ptr));
+      png_free(&dummy_struct, png_ptr);
+
+#     ifdef PNG_SETJMP_SUPPORTED
+         /* We may have a jmp_buf left to deallocate. */
+         png_free_jmpbuf(&dummy_struct);
+#     endif
+   }
+}
+
+/* Allocate memory.  For reasonable files, size should never exceed
+ * 64K.  However, zlib may allocate more than 64K if you don't tell
+ * it not to.  See zconf.h and png.h for more information.  zlib does
+ * need to allocate exactly 64K, so whatever you call here must
+ * have the ability to do that.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_calloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+{
+   png_voidp ret;
+
+   ret = png_malloc(png_ptr, size);
+
+   if (ret != NULL)
+      memset(ret, 0, size);
+
+   return ret;
+}
+
+/* png_malloc_base, an internal function added at libpng 1.6.0, does the work of
+ * allocating memory, taking into account limits and PNG_USER_MEM_SUPPORTED.
+ * Checking and error handling must happen outside this routine; it returns NULL
+ * if the allocation cannot be done (for any reason.)
+ */
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size),
+    PNG_ALLOCATED)
+{
+   /* Moved to png_malloc_base from png_malloc_default in 1.6.0; the DOS
+    * allocators have also been removed in 1.6.0, so any 16-bit system now has
+    * to implement a user memory handler.  This checks to be sure it isn't
+    * called with big numbers.
+    */
+#ifndef PNG_USER_MEM_SUPPORTED
+   PNG_UNUSED(png_ptr)
+#endif
+
+   /* Some compilers complain that this is always true.  However, it
+    * can be false when integer overflow happens.
+    */
+   if (size > 0 && size <= PNG_SIZE_MAX
+#     ifdef PNG_MAX_MALLOC_64K
+         && size <= 65536U
+#     endif
+      )
+   {
+#ifdef PNG_USER_MEM_SUPPORTED
+      if (png_ptr != NULL && png_ptr->malloc_fn != NULL)
+         return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size);
+
+      else
+#endif
+         return malloc((size_t)size); /* checked for truncation above */
+   }
+
+   else
+      return NULL;
+}
+
+#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
+   defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
+/* This is really here only to work round a spurious warning in GCC 4.6 and 4.7
+ * that arises because of the checks in png_realloc_array that are repeated in
+ * png_malloc_array.
+ */
+static png_voidp
+png_malloc_array_checked(png_const_structrp png_ptr, int nelements,
+    size_t element_size)
+{
+   png_alloc_size_t req = (png_alloc_size_t)nelements; /* known to be > 0 */
+
+   if (req <= PNG_SIZE_MAX/element_size)
+      return png_malloc_base(png_ptr, req * element_size);
+
+   /* The failure case when the request is too large */
+   return NULL;
+}
+
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_malloc_array,(png_const_structrp png_ptr, int nelements,
+    size_t element_size),PNG_ALLOCATED)
+{
+   if (nelements <= 0 || element_size == 0)
+      png_error(png_ptr, "internal error: array alloc");
+
+   return png_malloc_array_checked(png_ptr, nelements, element_size);
+}
+
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array,
+    int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED)
+{
+   /* These are internal errors: */
+   if (add_elements <= 0 || element_size == 0 || old_elements < 0 ||
+      (old_array == NULL && old_elements > 0))
+      png_error(png_ptr, "internal error: array realloc");
+
+   /* Check for overflow on the elements count (so the caller does not have to
+    * check.)
+    */
+   if (add_elements <= INT_MAX - old_elements)
+   {
+      png_voidp new_array = png_malloc_array_checked(png_ptr,
+          old_elements+add_elements, element_size);
+
+      if (new_array != NULL)
+      {
+         /* Because png_malloc_array worked the size calculations below cannot
+          * overflow.
+          */
+         if (old_elements > 0)
+            memcpy(new_array, old_array, element_size*(unsigned)old_elements);
+
+         memset((char*)new_array + element_size*(unsigned)old_elements, 0,
+             element_size*(unsigned)add_elements);
+
+         return new_array;
+      }
+   }
+
+   return NULL; /* error */
+}
+#endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */
+
+/* Various functions that have different error handling are derived from this.
+ * png_malloc always exists, but if PNG_USER_MEM_SUPPORTED is defined a separate
+ * function png_malloc_default is also provided.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+{
+   png_voidp ret;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   ret = png_malloc_base(png_ptr, size);
+
+   if (ret == NULL)
+       png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */
+
+   return ret;
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),
+    PNG_ALLOCATED PNG_DEPRECATED)
+{
+   png_voidp ret;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   /* Passing 'NULL' here bypasses the application provided memory handler. */
+   ret = png_malloc_base(NULL/*use malloc*/, size);
+
+   if (ret == NULL)
+      png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */
+
+   return ret;
+}
+#endif /* USER_MEM */
+
+/* This function was added at libpng version 1.2.3.  The png_malloc_warn()
+ * function will issue a png_warning and return NULL instead of issuing a
+ * png_error, if it fails to allocate the requested memory.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_warn,(png_const_structrp png_ptr, png_alloc_size_t size),
+    PNG_ALLOCATED)
+{
+   if (png_ptr != NULL)
+   {
+      png_voidp ret = png_malloc_base(png_ptr, size);
+
+      if (ret != NULL)
+         return ret;
+
+      png_warning(png_ptr, "Out of memory");
+   }
+
+   return NULL;
+}
+
+/* Free a pointer allocated by png_malloc().  If ptr is NULL, return
+ * without taking any action.
+ */
+void PNGAPI
+png_free(png_const_structrp png_ptr, png_voidp ptr)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if (png_ptr->free_fn != NULL)
+      png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr);
+
+   else
+      png_free_default(png_ptr, ptr);
+}
+
+PNG_FUNCTION(void,PNGAPI
+png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+#endif /* USER_MEM */
+
+   free(ptr);
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* This function is called when the application wants to use another method
+ * of allocating and freeing memory.
+ */
+void PNGAPI
+png_set_mem_fn(png_structrp png_ptr, png_voidp mem_ptr, png_malloc_ptr
+  malloc_fn, png_free_ptr free_fn)
+{
+   if (png_ptr != NULL)
+   {
+      png_ptr->mem_ptr = mem_ptr;
+      png_ptr->malloc_fn = malloc_fn;
+      png_ptr->free_fn = free_fn;
+   }
+}
+
+/* This function returns a pointer to the mem_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_mem_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return NULL;
+
+   return png_ptr->mem_ptr;
+}
+#endif /* USER_MEM */
+#endif /* READ || WRITE */
Index: /trunk/src/libs/libpng-1.6.45/pngpread.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngpread.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngpread.c	(revision 107811)
@@ -0,0 +1,1104 @@
+
+/* pngpread.c - read a png file in push mode
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+
+/* Push model modes */
+#define PNG_READ_SIG_MODE   0
+#define PNG_READ_CHUNK_MODE 1
+#define PNG_READ_IDAT_MODE  2
+#define PNG_READ_tEXt_MODE  4
+#define PNG_READ_zTXt_MODE  5
+#define PNG_READ_DONE_MODE  6
+#define PNG_READ_iTXt_MODE  7
+#define PNG_ERROR_MODE      8
+
+#define PNG_PUSH_SAVE_BUFFER_IF_FULL \
+if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
+   { png_push_save_buffer(png_ptr); return; }
+#define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
+if (png_ptr->buffer_size < N) \
+   { png_push_save_buffer(png_ptr); return; }
+
+void PNGAPI
+png_process_data(png_structrp png_ptr, png_inforp info_ptr,
+    png_bytep buffer, size_t buffer_size)
+{
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_push_restore_buffer(png_ptr, buffer, buffer_size);
+
+   while (png_ptr->buffer_size)
+   {
+      png_process_some_data(png_ptr, info_ptr);
+   }
+}
+
+size_t PNGAPI
+png_process_data_pause(png_structrp png_ptr, int save)
+{
+   if (png_ptr != NULL)
+   {
+      /* It's easiest for the caller if we do the save; then the caller doesn't
+       * have to supply the same data again:
+       */
+      if (save != 0)
+         png_push_save_buffer(png_ptr);
+      else
+      {
+         /* This includes any pending saved bytes: */
+         size_t remaining = png_ptr->buffer_size;
+         png_ptr->buffer_size = 0;
+
+         /* So subtract the saved buffer size, unless all the data
+          * is actually 'saved', in which case we just return 0
+          */
+         if (png_ptr->save_buffer_size < remaining)
+            return remaining - png_ptr->save_buffer_size;
+      }
+   }
+
+   return 0;
+}
+
+png_uint_32 PNGAPI
+png_process_data_skip(png_structrp png_ptr)
+{
+/* TODO: Deprecate and remove this API.
+ * Somewhere the implementation of this seems to have been lost,
+ * or abandoned.  It was only to support some internal back-door access
+ * to png_struct) in libpng-1.4.x.
+ */
+   png_app_warning(png_ptr,
+"png_process_data_skip is not implemented in any current version of libpng");
+   return 0;
+}
+
+/* What we do with the incoming data depends on what we were previously
+ * doing before we ran out of data...
+ */
+void /* PRIVATE */
+png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
+{
+   if (png_ptr == NULL)
+      return;
+
+   switch (png_ptr->process_mode)
+   {
+      case PNG_READ_SIG_MODE:
+      {
+         png_push_read_sig(png_ptr, info_ptr);
+         break;
+      }
+
+      case PNG_READ_CHUNK_MODE:
+      {
+         png_push_read_chunk(png_ptr, info_ptr);
+         break;
+      }
+
+      case PNG_READ_IDAT_MODE:
+      {
+         png_push_read_IDAT(png_ptr);
+         break;
+      }
+
+      default:
+      {
+         png_ptr->buffer_size = 0;
+         break;
+      }
+   }
+}
+
+/* Read any remaining signature bytes from the stream and compare them with
+ * the correct PNG signature.  It is possible that this routine is called
+ * with bytes already read from the signature, either because they have been
+ * checked by the calling application, or because of multiple calls to this
+ * routine.
+ */
+void /* PRIVATE */
+png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
+{
+   size_t num_checked = png_ptr->sig_bytes; /* SAFE, does not exceed 8 */
+   size_t num_to_check = 8 - num_checked;
+
+   if (png_ptr->buffer_size < num_to_check)
+   {
+      num_to_check = png_ptr->buffer_size;
+   }
+
+   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
+       num_to_check);
+   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
+
+   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
+   {
+      if (num_checked < 4 &&
+          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4) != 0)
+         png_error(png_ptr, "Not a PNG file");
+
+      else
+         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+   }
+   else
+   {
+      if (png_ptr->sig_bytes >= 8)
+      {
+         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+      }
+   }
+}
+
+void /* PRIVATE */
+png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
+{
+   png_uint_32 chunk_name;
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   int keep; /* unknown handling method */
+#endif
+
+   /* First we make sure we have enough data for the 4-byte chunk name
+    * and the 4-byte chunk length before proceeding with decoding the
+    * chunk data.  To fully decode each of these chunks, we also make
+    * sure we have enough data in the buffer for the 4-byte CRC at the
+    * end of every chunk (except IDAT, which is handled separately).
+    */
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+   {
+      png_byte chunk_length[4];
+      png_byte chunk_tag[4];
+
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+      png_push_fill_buffer(png_ptr, chunk_length, 4);
+      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
+      png_reset_crc(png_ptr);
+      png_crc_read(png_ptr, chunk_tag, 4);
+      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
+      png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+      png_check_chunk_length(png_ptr, png_ptr->push_length);
+      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+   }
+
+   chunk_name = png_ptr->chunk_name;
+
+   if (chunk_name == png_IDAT)
+   {
+      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+
+      /* If we reach an IDAT chunk, this means we have read all of the
+       * header chunks, and we can start reading the image (or if this
+       * is called after the image has been read - we have an error).
+       */
+      if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+         png_error(png_ptr, "Missing IHDR before IDAT");
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+          (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+         png_error(png_ptr, "Missing PLTE before IDAT");
+
+      png_ptr->process_mode = PNG_READ_IDAT_MODE;
+
+      if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+         if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
+            if (png_ptr->push_length == 0)
+               return;
+
+      png_ptr->mode |= PNG_HAVE_IDAT;
+
+      if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+         png_benign_error(png_ptr, "Too many IDATs found");
+   }
+
+   if (chunk_name == png_IHDR)
+   {
+      if (png_ptr->push_length != 13)
+         png_error(png_ptr, "Invalid IHDR length");
+
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+   else if (chunk_name == png_IEND)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
+
+      png_ptr->process_mode = PNG_READ_DONE_MODE;
+      png_push_have_end(png_ptr, info_ptr);
+   }
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
+
+      if (chunk_name == png_PLTE)
+         png_ptr->mode |= PNG_HAVE_PLTE;
+   }
+#endif
+
+   else if (chunk_name == png_PLTE)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+   else if (chunk_name == png_IDAT)
+   {
+      png_ptr->idat_size = png_ptr->push_length;
+      png_ptr->process_mode = PNG_READ_IDAT_MODE;
+      png_push_have_info(png_ptr, info_ptr);
+      png_ptr->zstream.avail_out =
+          (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
+          png_ptr->iwidth) + 1;
+      png_ptr->zstream.next_out = png_ptr->row_buf;
+      return;
+   }
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+   else if (png_ptr->chunk_name == png_gAMA)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_sBIT_SUPPORTED
+   else if (png_ptr->chunk_name == png_sBIT)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_cHRM_SUPPORTED
+   else if (png_ptr->chunk_name == png_cHRM)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_eXIf_SUPPORTED
+   else if (png_ptr->chunk_name == png_eXIf)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_eXIf(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_sRGB_SUPPORTED
+   else if (chunk_name == png_sRGB)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_iCCP_SUPPORTED
+   else if (png_ptr->chunk_name == png_iCCP)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_sPLT_SUPPORTED
+   else if (chunk_name == png_sPLT)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_tRNS_SUPPORTED
+   else if (chunk_name == png_tRNS)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_bKGD_SUPPORTED
+   else if (chunk_name == png_bKGD)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_hIST_SUPPORTED
+   else if (chunk_name == png_hIST)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_pHYs_SUPPORTED
+   else if (chunk_name == png_pHYs)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_oFFs_SUPPORTED
+   else if (chunk_name == png_oFFs)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+   else if (chunk_name == png_pCAL)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_sCAL_SUPPORTED
+   else if (chunk_name == png_sCAL)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_tIME_SUPPORTED
+   else if (chunk_name == png_tIME)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_tEXt_SUPPORTED
+   else if (chunk_name == png_tEXt)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_zTXt_SUPPORTED
+   else if (chunk_name == png_zTXt)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+#endif
+#ifdef PNG_READ_iTXt_SUPPORTED
+   else if (chunk_name == png_iTXt)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+
+   else
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_FULL
+      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
+          PNG_HANDLE_CHUNK_AS_DEFAULT);
+   }
+
+   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+}
+
+void PNGCBAPI
+png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, size_t length)
+{
+   png_bytep ptr;
+
+   if (png_ptr == NULL)
+      return;
+
+   ptr = buffer;
+   if (png_ptr->save_buffer_size != 0)
+   {
+      size_t save_size;
+
+      if (length < png_ptr->save_buffer_size)
+         save_size = length;
+
+      else
+         save_size = png_ptr->save_buffer_size;
+
+      memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
+      length -= save_size;
+      ptr += save_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->save_buffer_size -= save_size;
+      png_ptr->save_buffer_ptr += save_size;
+   }
+   if (length != 0 && png_ptr->current_buffer_size != 0)
+   {
+      size_t save_size;
+
+      if (length < png_ptr->current_buffer_size)
+         save_size = length;
+
+      else
+         save_size = png_ptr->current_buffer_size;
+
+      memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
+      png_ptr->buffer_size -= save_size;
+      png_ptr->current_buffer_size -= save_size;
+      png_ptr->current_buffer_ptr += save_size;
+   }
+}
+
+void /* PRIVATE */
+png_push_save_buffer(png_structrp png_ptr)
+{
+   if (png_ptr->save_buffer_size != 0)
+   {
+      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
+      {
+         size_t i, istop;
+         png_bytep sp;
+         png_bytep dp;
+
+         istop = png_ptr->save_buffer_size;
+         for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
+             i < istop; i++, sp++, dp++)
+         {
+            *dp = *sp;
+         }
+      }
+   }
+   if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
+       png_ptr->save_buffer_max)
+   {
+      size_t new_max;
+      png_bytep old_buffer;
+
+      if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
+          (png_ptr->current_buffer_size + 256))
+      {
+         png_error(png_ptr, "Potential overflow of save_buffer");
+      }
+
+      new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
+      old_buffer = png_ptr->save_buffer;
+      png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
+          (size_t)new_max);
+
+      if (png_ptr->save_buffer == NULL)
+      {
+         png_free(png_ptr, old_buffer);
+         png_error(png_ptr, "Insufficient memory for save_buffer");
+      }
+
+      if (old_buffer)
+         memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
+      else if (png_ptr->save_buffer_size)
+         png_error(png_ptr, "save_buffer error");
+      png_free(png_ptr, old_buffer);
+      png_ptr->save_buffer_max = new_max;
+   }
+   if (png_ptr->current_buffer_size)
+   {
+      memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
+         png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
+      png_ptr->save_buffer_size += png_ptr->current_buffer_size;
+      png_ptr->current_buffer_size = 0;
+   }
+   png_ptr->save_buffer_ptr = png_ptr->save_buffer;
+   png_ptr->buffer_size = 0;
+}
+
+void /* PRIVATE */
+png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
+    size_t buffer_length)
+{
+   png_ptr->current_buffer = buffer;
+   png_ptr->current_buffer_size = buffer_length;
+   png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
+   png_ptr->current_buffer_ptr = png_ptr->current_buffer;
+}
+
+void /* PRIVATE */
+png_push_read_IDAT(png_structrp png_ptr)
+{
+   if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+   {
+      png_byte chunk_length[4];
+      png_byte chunk_tag[4];
+
+      /* TODO: this code can be commoned up with the same code in push_read */
+      PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+      png_push_fill_buffer(png_ptr, chunk_length, 4);
+      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
+      png_reset_crc(png_ptr);
+      png_crc_read(png_ptr, chunk_tag, 4);
+      png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
+      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+
+      if (png_ptr->chunk_name != png_IDAT)
+      {
+         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+
+         if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+            png_error(png_ptr, "Not enough compressed data");
+
+         return;
+      }
+
+      png_ptr->idat_size = png_ptr->push_length;
+   }
+
+   if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
+   {
+      size_t save_size = png_ptr->save_buffer_size;
+      png_uint_32 idat_size = png_ptr->idat_size;
+
+      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+       * are of different types and we don't know which variable has the fewest
+       * bits.  Carefully select the smaller and cast it to the type of the
+       * larger - this cannot overflow.  Do not cast in the following test - it
+       * will break on either 16-bit or 64-bit platforms.
+       */
+      if (idat_size < save_size)
+         save_size = (size_t)idat_size;
+
+      else
+         idat_size = (png_uint_32)save_size;
+
+      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+      png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+      png_ptr->idat_size -= idat_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->save_buffer_size -= save_size;
+      png_ptr->save_buffer_ptr += save_size;
+   }
+
+   if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
+   {
+      size_t save_size = png_ptr->current_buffer_size;
+      png_uint_32 idat_size = png_ptr->idat_size;
+
+      /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+       * are of different types and we don't know which variable has the fewest
+       * bits.  Carefully select the smaller and cast it to the type of the
+       * larger - this cannot overflow.
+       */
+      if (idat_size < save_size)
+         save_size = (size_t)idat_size;
+
+      else
+         idat_size = (png_uint_32)save_size;
+
+      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+      png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+      png_ptr->idat_size -= idat_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->current_buffer_size -= save_size;
+      png_ptr->current_buffer_ptr += save_size;
+   }
+
+   if (png_ptr->idat_size == 0)
+   {
+      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
+      png_crc_finish(png_ptr, 0);
+      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+      png_ptr->mode |= PNG_AFTER_IDAT;
+      png_ptr->zowner = 0;
+   }
+}
+
+void /* PRIVATE */
+png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
+    size_t buffer_length)
+{
+   /* The caller checks for a non-zero buffer length. */
+   if (!(buffer_length > 0) || buffer == NULL)
+      png_error(png_ptr, "No IDAT data (internal error)");
+
+   /* This routine must process all the data it has been given
+    * before returning, calling the row callback as required to
+    * handle the uncompressed results.
+    */
+   png_ptr->zstream.next_in = buffer;
+   /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
+   png_ptr->zstream.avail_in = (uInt)buffer_length;
+
+   /* Keep going until the decompressed data is all processed
+    * or the stream marked as finished.
+    */
+   while (png_ptr->zstream.avail_in > 0 &&
+      (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+   {
+      int ret;
+
+      /* We have data for zlib, but we must check that zlib
+       * has someplace to put the results.  It doesn't matter
+       * if we don't expect any results -- it may be the input
+       * data is just the LZ end code.
+       */
+      if (!(png_ptr->zstream.avail_out > 0))
+      {
+         /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
+         png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
+             png_ptr->iwidth) + 1);
+
+         png_ptr->zstream.next_out = png_ptr->row_buf;
+      }
+
+      /* Using Z_SYNC_FLUSH here means that an unterminated
+       * LZ stream (a stream with a missing end code) can still
+       * be handled, otherwise (Z_NO_FLUSH) a future zlib
+       * implementation might defer output and therefore
+       * change the current behavior (see comments in inflate.c
+       * for why this doesn't happen at present with zlib 1.2.5).
+       */
+      ret = PNG_INFLATE(png_ptr, Z_SYNC_FLUSH);
+
+      /* Check for any failure before proceeding. */
+      if (ret != Z_OK && ret != Z_STREAM_END)
+      {
+         /* Terminate the decompression. */
+         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+         png_ptr->zowner = 0;
+
+         /* This may be a truncated stream (missing or
+          * damaged end code).  Treat that as a warning.
+          */
+         if (png_ptr->row_number >= png_ptr->num_rows ||
+             png_ptr->pass > 6)
+            png_warning(png_ptr, "Truncated compressed data in IDAT");
+
+         else
+         {
+            if (ret == Z_DATA_ERROR)
+               png_benign_error(png_ptr, "IDAT: ADLER32 checksum mismatch");
+            else
+               png_error(png_ptr, "Decompression error in IDAT");
+         }
+
+         /* Skip the check on unprocessed input */
+         return;
+      }
+
+      /* Did inflate output any data? */
+      if (png_ptr->zstream.next_out != png_ptr->row_buf)
+      {
+         /* Is this unexpected data after the last row?
+          * If it is, artificially terminate the LZ output
+          * here.
+          */
+         if (png_ptr->row_number >= png_ptr->num_rows ||
+             png_ptr->pass > 6)
+         {
+            /* Extra data. */
+            png_warning(png_ptr, "Extra compressed data in IDAT");
+            png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+            png_ptr->zowner = 0;
+
+            /* Do no more processing; skip the unprocessed
+             * input check below.
+             */
+            return;
+         }
+
+         /* Do we have a complete row? */
+         if (png_ptr->zstream.avail_out == 0)
+            png_push_process_row(png_ptr);
+      }
+
+      /* And check for the end of the stream. */
+      if (ret == Z_STREAM_END)
+         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+   }
+
+   /* All the data should have been processed, if anything
+    * is left at this point we have bytes of IDAT data
+    * after the zlib end code.
+    */
+   if (png_ptr->zstream.avail_in > 0)
+      png_warning(png_ptr, "Extra compression data in IDAT");
+}
+
+void /* PRIVATE */
+png_push_process_row(png_structrp png_ptr)
+{
+   /* 1.5.6: row_info moved out of png_struct to a local here. */
+   png_row_info row_info;
+
+   row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
+   row_info.color_type = png_ptr->color_type;
+   row_info.bit_depth = png_ptr->bit_depth;
+   row_info.channels = png_ptr->channels;
+   row_info.pixel_depth = png_ptr->pixel_depth;
+   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+   if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
+   {
+      if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
+         png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
+            png_ptr->prev_row + 1, png_ptr->row_buf[0]);
+      else
+         png_error(png_ptr, "bad adaptive filter value");
+   }
+
+   /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
+    * 1.5.6, while the buffer really is this big in current versions of libpng
+    * it may not be in the future, so this was changed just to copy the
+    * interlaced row count:
+    */
+   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+   if (png_ptr->transformations != 0)
+      png_do_read_transformations(png_ptr, &row_info);
+#endif
+
+   /* The transformed pixel depth should match the depth now in row_info. */
+   if (png_ptr->transformed_pixel_depth == 0)
+   {
+      png_ptr->transformed_pixel_depth = row_info.pixel_depth;
+      if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
+         png_error(png_ptr, "progressive row overflow");
+   }
+
+   else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
+      png_error(png_ptr, "internal progressive row size calculation error");
+
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* Expand interlaced rows to full size */
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      if (png_ptr->pass < 6)
+         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
+             png_ptr->transformations);
+
+      switch (png_ptr->pass)
+      {
+         case 0:
+         {
+            int i;
+            for (i = 0; i < 8 && png_ptr->pass == 0; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
+            }
+
+            if (png_ptr->pass == 2) /* Pass 1 might be empty */
+            {
+               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            if (png_ptr->pass == 4 && png_ptr->height <= 4)
+            {
+               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            if (png_ptr->pass == 6 && png_ptr->height <= 4)
+            {
+                png_push_have_row(png_ptr, NULL);
+                png_read_push_finish_row(png_ptr);
+            }
+
+            break;
+         }
+
+         case 1:
+         {
+            int i;
+            for (i = 0; i < 8 && png_ptr->pass == 1; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 2) /* Skip top 4 generated rows */
+            {
+               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            break;
+         }
+
+         case 2:
+         {
+            int i;
+
+            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+            {
+               png_push_have_row(png_ptr, NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 4) /* Pass 3 might be empty */
+            {
+               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            break;
+         }
+
+         case 3:
+         {
+            int i;
+
+            for (i = 0; i < 4 && png_ptr->pass == 3; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 4) /* Skip top two generated rows */
+            {
+               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+               {
+                  png_push_have_row(png_ptr, NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+
+            break;
+         }
+
+         case 4:
+         {
+            int i;
+
+            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+            {
+               png_push_have_row(png_ptr, NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 6) /* Pass 5 might be empty */
+            {
+               png_push_have_row(png_ptr, NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            break;
+         }
+
+         case 5:
+         {
+            int i;
+
+            for (i = 0; i < 2 && png_ptr->pass == 5; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            if (png_ptr->pass == 6) /* Skip top generated row */
+            {
+               png_push_have_row(png_ptr, NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+
+            break;
+         }
+
+         default:
+         case 6:
+         {
+            png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+            png_read_push_finish_row(png_ptr);
+
+            if (png_ptr->pass != 6)
+               break;
+
+            png_push_have_row(png_ptr, NULL);
+            png_read_push_finish_row(png_ptr);
+         }
+      }
+   }
+   else
+#endif
+   {
+      png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+      png_read_push_finish_row(png_ptr);
+   }
+}
+
+void /* PRIVATE */
+png_read_push_finish_row(png_structrp png_ptr)
+{
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
+
+   /* Height of interlace block.  This is not currently used - if you need
+    * it, uncomment it here and in png.h
+   static const png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+   */
+#endif
+
+   png_ptr->row_number++;
+   if (png_ptr->row_number < png_ptr->num_rows)
+      return;
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   if (png_ptr->interlaced != 0)
+   {
+      png_ptr->row_number = 0;
+      memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+      do
+      {
+         png_ptr->pass++;
+         if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
+             (png_ptr->pass == 3 && png_ptr->width < 3) ||
+             (png_ptr->pass == 5 && png_ptr->width < 2))
+            png_ptr->pass++;
+
+         if (png_ptr->pass > 7)
+            png_ptr->pass--;
+
+         if (png_ptr->pass >= 7)
+            break;
+
+         png_ptr->iwidth = (png_ptr->width +
+             png_pass_inc[png_ptr->pass] - 1 -
+             png_pass_start[png_ptr->pass]) /
+             png_pass_inc[png_ptr->pass];
+
+         if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+            break;
+
+         png_ptr->num_rows = (png_ptr->height +
+             png_pass_yinc[png_ptr->pass] - 1 -
+             png_pass_ystart[png_ptr->pass]) /
+             png_pass_yinc[png_ptr->pass];
+
+      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
+   }
+#endif /* READ_INTERLACING */
+}
+
+void /* PRIVATE */
+png_push_have_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+   if (png_ptr->info_fn != NULL)
+      (*(png_ptr->info_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+   if (png_ptr->end_fn != NULL)
+      (*(png_ptr->end_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_row(png_structrp png_ptr, png_bytep row)
+{
+   if (png_ptr->row_fn != NULL)
+      (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
+          (int)png_ptr->pass);
+}
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+void PNGAPI
+png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
+    png_const_bytep new_row)
+{
+   if (png_ptr == NULL)
+      return;
+
+   /* new_row is a flag here - if it is NULL then the app callback was called
+    * from an empty row (see the calls to png_struct::row_fn below), otherwise
+    * it must be png_ptr->row_buf+1
+    */
+   if (new_row != NULL)
+      png_combine_row(png_ptr, old_row, 1/*blocky display*/);
+}
+#endif /* READ_INTERLACING */
+
+void PNGAPI
+png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
+    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
+    png_progressive_end_ptr end_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->info_fn = info_fn;
+   png_ptr->row_fn = row_fn;
+   png_ptr->end_fn = end_fn;
+
+   png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
+}
+
+png_voidp PNGAPI
+png_get_progressive_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return NULL;
+
+   return png_ptr->io_ptr;
+}
+#endif /* PROGRESSIVE_READ */
Index: /trunk/src/libs/libpng-1.6.45/pngpriv.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngpriv.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngpriv.h	(revision 107811)
@@ -0,0 +1,2226 @@
+
+/* pngpriv.h - private declarations for use inside libpng
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* The symbols declared in this file (including the functions declared
+ * as extern) are PRIVATE.  They are not part of the libpng public
+ * interface, and are not recommended for use by regular applications.
+ * Some of them may become public in the future; others may stay private,
+ * change in an incompatible way, or even disappear.
+ * Although the libpng users are not forbidden to include this header,
+ * they should be well aware of the issues that may arise from doing so.
+ */
+
+#ifndef PNGPRIV_H
+#define PNGPRIV_H
+
+/* Feature Test Macros.  The following are defined here to ensure that correctly
+ * implemented libraries reveal the APIs libpng needs to build and hide those
+ * that are not needed and potentially damaging to the compilation.
+ *
+ * Feature Test Macros must be defined before any system header is included (see
+ * POSIX 1003.1 2.8.2 "POSIX Symbols."
+ *
+ * These macros only have an effect if the operating system supports either
+ * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
+ * Windows/Visual Studio) there is no effect; the OS specific tests below are
+ * still required (as of 2011-05-02.)
+ */
+#ifndef _POSIX_SOURCE
+#  define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+/* Standard library headers not required by png.h: */
+#  include <stdlib.h>
+#  include <string.h>
+#endif
+
+#define PNGLIB_BUILD /*libpng is being built, not used*/
+
+/* If HAVE_CONFIG_H is defined during the build then the build system must
+ * provide an appropriate "config.h" file on the include path.  The header file
+ * must provide definitions as required below (search for "HAVE_CONFIG_H");
+ * see configure.ac for more details of the requirements.  The macro
+ * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on
+ * 'configure'; define this macro to prevent the configure build including the
+ * configure generated config.h.  Libpng is expected to compile without *any*
+ * special build system support on a reasonably ANSI-C compliant system.
+ */
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+#  include <config.h>
+
+   /* Pick up the definition of 'restrict' from config.h if it was read: */
+#  define PNG_RESTRICT restrict
+#endif
+
+/* To support symbol prefixing it is necessary to know *before* including png.h
+ * whether the fixed point (and maybe other) APIs are exported, because if they
+ * are not internal definitions may be required.  This is handled below just
+ * before png.h is included, but load the configuration now if it is available.
+ */
+#ifndef PNGLCONF_H
+#  include "pnglibconf.h"
+#endif
+
+/* Local renames may change non-exported API functions from png.h */
+#if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
+#  include "pngprefix.h"
+#endif
+
+#ifdef PNG_USER_CONFIG
+#  include "pngusr.h"
+   /* These should have been defined in pngusr.h */
+#  ifndef PNG_USER_PRIVATEBUILD
+#    define PNG_USER_PRIVATEBUILD "Custom libpng build"
+#  endif
+#  ifndef PNG_USER_DLLFNAME_POSTFIX
+#    define PNG_USER_DLLFNAME_POSTFIX "Cb"
+#  endif
+#endif
+
+/* Compile time options.
+ * =====================
+ * In a multi-arch build the compiler may compile the code several times for the
+ * same object module, producing different binaries for different architectures.
+ * When this happens configure-time setting of the target host options cannot be
+ * done and this interferes with the handling of the ARM NEON optimizations, and
+ * possibly other similar optimizations.  Put additional tests here; in general
+ * this is needed when the same option can be changed at both compile time and
+ * run time depending on the target OS (i.e. iOS vs Android.)
+ *
+ * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because
+ * this is not possible with certain compilers (Oracle SUN OS CC), as a result
+ * it is necessary to ensure that all extern functions that *might* be used
+ * regardless of $(CFLAGS) get declared in this file.  The test on __ARM_NEON__
+ * below is one example of this behavior because it is controlled by the
+ * presence or not of -mfpu=neon on the GCC command line, it is possible to do
+ * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely
+ * do this.
+ */
+#ifndef PNG_ARM_NEON_OPT
+   /* ARM NEON optimizations are being controlled by the compiler settings,
+    * typically the target FPU.  If the FPU has been set to NEON (-mfpu=neon
+    * with GCC) then the compiler will define __ARM_NEON__ and we can rely
+    * unconditionally on NEON instructions not crashing, otherwise we must
+    * disable use of NEON instructions.
+    *
+    * NOTE: at present these optimizations depend on 'ALIGNED_MEMORY', so they
+    * can only be turned on automatically if that is supported too.  If
+    * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail
+    * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
+    * off.
+    *
+    * Note that gcc-4.9 defines __ARM_NEON instead of the deprecated
+    * __ARM_NEON__, so we check both variants.
+    *
+    * To disable ARM_NEON optimizations entirely, and skip compiling the
+    * associated assembler code, pass --enable-arm-neon=no to configure
+    * or put -DPNG_ARM_NEON_OPT=0 in CPPFLAGS.
+    */
+#  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
+   defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+#     define PNG_ARM_NEON_OPT 2
+#  else
+#     define PNG_ARM_NEON_OPT 0
+#  endif
+#endif
+
+#if PNG_ARM_NEON_OPT > 0
+   /* NEON optimizations are to be at least considered by libpng, so enable the
+    * callbacks to do this.
+    */
+#  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
+
+   /* By default the 'intrinsics' code in arm/filter_neon_intrinsics.c is used
+    * if possible - if __ARM_NEON__ is set and the compiler version is not known
+    * to be broken.  This is controlled by PNG_ARM_NEON_IMPLEMENTATION which can
+    * be:
+    *
+    *    1  The intrinsics code (the default with __ARM_NEON__)
+    *    2  The hand coded assembler (the default without __ARM_NEON__)
+    *
+    * It is possible to set PNG_ARM_NEON_IMPLEMENTATION in CPPFLAGS, however
+    * this is *NOT* supported and may cease to work even after a minor revision
+    * to libpng.  It *is* valid to do this for testing purposes, e.g. speed
+    * testing or a new compiler, but the results should be communicated to the
+    * libpng implementation list for incorporation in the next minor release.
+    */
+#  ifndef PNG_ARM_NEON_IMPLEMENTATION
+#     if defined(__ARM_NEON__) || defined(__ARM_NEON)
+#        if defined(__clang__)
+            /* At present it is unknown by the libpng developers which versions
+             * of clang support the intrinsics, however some or perhaps all
+             * versions do not work with the assembler so this may be
+             * irrelevant, so just use the default (do nothing here.)
+             */
+#        elif defined(__GNUC__)
+            /* GCC 4.5.4 NEON support is known to be broken.  4.6.3 is known to
+             * work, so if this *is* GCC, or G++, look for a version >4.5
+             */
+#           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
+#              define PNG_ARM_NEON_IMPLEMENTATION 2
+#           endif /* no GNUC support */
+#        endif /* __GNUC__ */
+#     else /* !defined __ARM_NEON__ */
+         /* The 'intrinsics' code simply won't compile without this -mfpu=neon:
+          */
+#        if !defined(__aarch64__) && !defined(_M_ARM64)
+            /* The assembler code currently does not work on ARM64 */
+#          define PNG_ARM_NEON_IMPLEMENTATION 2
+#        endif /* __aarch64__ */
+#     endif /* __ARM_NEON__ */
+#  endif /* !PNG_ARM_NEON_IMPLEMENTATION */
+
+#  ifndef PNG_ARM_NEON_IMPLEMENTATION
+      /* Use the intrinsics code by default. */
+#     define PNG_ARM_NEON_IMPLEMENTATION 1
+#  endif
+#else /* PNG_ARM_NEON_OPT == 0 */
+#     define PNG_ARM_NEON_IMPLEMENTATION 0
+#endif /* PNG_ARM_NEON_OPT > 0 */
+
+#ifndef PNG_MIPS_MSA_OPT
+#  if defined(__mips_msa) && (__mips_isa_rev >= 5) && \
+   defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+#     define PNG_MIPS_MSA_OPT 2
+#  else
+#     define PNG_MIPS_MSA_OPT 0
+#  endif
+#endif
+
+#ifndef PNG_MIPS_MMI_OPT
+#  ifdef PNG_MIPS_MMI
+#    if defined(__mips_loongson_mmi) && (_MIPS_SIM == _ABI64) && \
+     defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+#       define PNG_MIPS_MMI_OPT 1
+#    else
+#       define PNG_MIPS_MMI_OPT 0
+#    endif
+#  else
+#    define PNG_MIPS_MMI_OPT 0
+#  endif
+#endif
+
+#ifndef PNG_POWERPC_VSX_OPT
+#  if defined(__PPC64__) && defined(__ALTIVEC__) && defined(__VSX__)
+#     define PNG_POWERPC_VSX_OPT 2
+#  else
+#     define PNG_POWERPC_VSX_OPT 0
+#  endif
+#endif
+
+#ifndef PNG_LOONGARCH_LSX_OPT
+#  if defined(__loongarch_sx)
+#     define PNG_LOONGARCH_LSX_OPT 1
+#  else
+#     define PNG_LOONGARCH_LSX_OPT 0
+#  endif
+#endif
+
+#ifndef PNG_INTEL_SSE_OPT
+#   ifdef PNG_INTEL_SSE
+      /* Only check for SSE if the build configuration has been modified to
+       * enable SSE optimizations.  This means that these optimizations will
+       * be off by default.  See contrib/intel for more details.
+       */
+#      if defined(__SSE4_1__) || defined(__AVX__) || defined(__SSSE3__) || \
+       defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
+       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
+#         define PNG_INTEL_SSE_OPT 1
+#      else
+#         define PNG_INTEL_SSE_OPT 0
+#      endif
+#   else
+#      define PNG_INTEL_SSE_OPT 0
+#   endif
+#endif
+
+#if PNG_INTEL_SSE_OPT > 0
+#   ifndef PNG_INTEL_SSE_IMPLEMENTATION
+#      if defined(__SSE4_1__) || defined(__AVX__)
+          /* We are not actually using AVX, but checking for AVX is the best
+             way we can detect SSE4.1 and SSSE3 on MSVC.
+          */
+#         define PNG_INTEL_SSE_IMPLEMENTATION 3
+#      elif defined(__SSSE3__)
+#         define PNG_INTEL_SSE_IMPLEMENTATION 2
+#      elif defined(__SSE2__) || defined(_M_X64) || defined(_M_AMD64) || \
+       (defined(_M_IX86_FP) && _M_IX86_FP >= 2)
+#         define PNG_INTEL_SSE_IMPLEMENTATION 1
+#      else
+#         define PNG_INTEL_SSE_IMPLEMENTATION 0
+#      endif
+#   endif
+
+#   if PNG_INTEL_SSE_IMPLEMENTATION > 0
+#      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_sse2
+#   endif
+#else
+#   define PNG_INTEL_SSE_IMPLEMENTATION 0
+#endif
+
+#if PNG_MIPS_MSA_OPT > 0
+#  ifndef PNG_MIPS_MSA_IMPLEMENTATION
+#     if defined(__mips_msa)
+#        if defined(__clang__)
+#        elif defined(__GNUC__)
+#           if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
+#              define PNG_MIPS_MSA_IMPLEMENTATION 2
+#           endif /* no GNUC support */
+#        endif /* __GNUC__ */
+#     else /* !defined __mips_msa */
+#        define PNG_MIPS_MSA_IMPLEMENTATION 2
+#     endif /* __mips_msa */
+#  endif /* !PNG_MIPS_MSA_IMPLEMENTATION */
+
+#  ifndef PNG_MIPS_MSA_IMPLEMENTATION
+#     define PNG_MIPS_MSA_IMPLEMENTATION 1
+#     define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_mips
+#  endif
+#else
+#  define PNG_MIPS_MSA_IMPLEMENTATION 0
+#endif /* PNG_MIPS_MSA_OPT > 0 */
+
+#if PNG_MIPS_MMI_OPT > 0
+#  ifndef PNG_MIPS_MMI_IMPLEMENTATION
+#     if defined(__mips_loongson_mmi) && (_MIPS_SIM == _ABI64)
+#        define PNG_MIPS_MMI_IMPLEMENTATION 2
+#     else /* !defined __mips_loongson_mmi  || _MIPS_SIM != _ABI64 */
+#        define PNG_MIPS_MMI_IMPLEMENTATION 0
+#     endif /* __mips_loongson_mmi  && _MIPS_SIM == _ABI64 */
+#  endif /* !PNG_MIPS_MMI_IMPLEMENTATION */
+
+#   if PNG_MIPS_MMI_IMPLEMENTATION > 0
+#      define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_mips
+#   endif
+#else
+#   define PNG_MIPS_MMI_IMPLEMENTATION 0
+#endif /* PNG_MIPS_MMI_OPT > 0 */
+
+#if PNG_POWERPC_VSX_OPT > 0
+#  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_vsx
+#  define PNG_POWERPC_VSX_IMPLEMENTATION 1
+#else
+#  define PNG_POWERPC_VSX_IMPLEMENTATION 0
+#endif
+
+#if PNG_LOONGARCH_LSX_OPT > 0
+#   define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_lsx
+#   define PNG_LOONGARCH_LSX_IMPLEMENTATION 1
+#else
+#   define PNG_LOONGARCH_LSX_IMPLEMENTATION 0
+#endif
+
+/* Is this a build of a DLL where compilation of the object modules requires
+ * different preprocessor settings to those required for a simple library?  If
+ * so PNG_BUILD_DLL must be set.
+ *
+ * If libpng is used inside a DLL but that DLL does not export the libpng APIs
+ * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
+ * static library of libpng then link the DLL against that.
+ */
+#ifndef PNG_BUILD_DLL
+#  ifdef DLL_EXPORT
+      /* This is set by libtool when files are compiled for a DLL; libtool
+       * always compiles twice, even on systems where it isn't necessary.  Set
+       * PNG_BUILD_DLL in case it is necessary:
+       */
+#     define PNG_BUILD_DLL
+#  else
+#     ifdef _WINDLL
+         /* This is set by the Microsoft Visual Studio IDE in projects that
+          * build a DLL.  It can't easily be removed from those projects (it
+          * isn't visible in the Visual Studio UI) so it is a fairly reliable
+          * indication that PNG_IMPEXP needs to be set to the DLL export
+          * attributes.
+          */
+#        define PNG_BUILD_DLL
+#     else
+#        ifdef __DLL__
+            /* This is set by the Borland C system when compiling for a DLL
+             * (as above.)
+             */
+#           define PNG_BUILD_DLL
+#        else
+            /* Add additional compiler cases here. */
+#        endif
+#     endif
+#  endif
+#endif /* Setting PNG_BUILD_DLL if required */
+
+/* See pngconf.h for more details: the builder of the library may set this on
+ * the command line to the right thing for the specific compilation system or it
+ * may be automagically set above (at present we know of no system where it does
+ * need to be set on the command line.)
+ *
+ * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
+ * setting it to the "import" setting for a DLL build.
+ */
+#ifndef PNG_IMPEXP
+#  ifdef PNG_BUILD_DLL
+#     define PNG_IMPEXP PNG_DLL_EXPORT
+#  else
+      /* Not building a DLL, or the DLL doesn't require specific export
+       * definitions.
+       */
+#     define PNG_IMPEXP
+#  endif
+#endif
+
+/* No warnings for private or deprecated functions in the build: */
+#ifndef PNG_DEPRECATED
+#  define PNG_DEPRECATED
+#endif
+#ifndef PNG_PRIVATE
+#  define PNG_PRIVATE
+#endif
+
+/* Symbol preprocessing support.
+ *
+ * To enable listing global, but internal, symbols the following macros should
+ * always be used to declare an extern data or function object in this file.
+ */
+#ifndef PNG_INTERNAL_DATA
+#  define PNG_INTERNAL_DATA(type, name, array) PNG_LINKAGE_DATA type name array
+#endif
+
+#ifndef PNG_INTERNAL_FUNCTION
+#  define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
+      PNG_LINKAGE_FUNCTION PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
+#endif
+
+#ifndef PNG_INTERNAL_CALLBACK
+#  define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
+      PNG_LINKAGE_CALLBACK PNG_FUNCTION(type, (PNGCBAPI name), args,\
+         PNG_EMPTY attributes)
+#endif
+
+/* If floating or fixed point APIs are disabled they may still be compiled
+ * internally.  To handle this make sure they are declared as the appropriate
+ * internal extern function (otherwise the symbol prefixing stuff won't work and
+ * the functions will be used without definitions.)
+ *
+ * NOTE: although all the API functions are declared here they are not all
+ * actually built!  Because the declarations are still made it is necessary to
+ * fake out types that they depend on.
+ */
+#ifndef PNG_FP_EXPORT
+#  ifndef PNG_FLOATING_POINT_SUPPORTED
+#     define PNG_FP_EXPORT(ordinal, type, name, args)\
+         PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
+#     ifndef PNG_VERSION_INFO_ONLY
+         typedef struct png_incomplete png_double;
+         typedef png_double*           png_doublep;
+         typedef const png_double*     png_const_doublep;
+         typedef png_double**          png_doublepp;
+#     endif
+#  endif
+#endif
+#ifndef PNG_FIXED_EXPORT
+#  ifndef PNG_FIXED_POINT_SUPPORTED
+#     define PNG_FIXED_EXPORT(ordinal, type, name, args)\
+         PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
+#  endif
+#endif
+
+#include "png.h"
+
+/* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
+#ifndef PNG_DLL_EXPORT
+#  define PNG_DLL_EXPORT
+#endif
+
+/* This is a global switch to set the compilation for an installed system
+ * (a release build).  It can be set for testing debug builds to ensure that
+ * they will compile when the build type is switched to RC or STABLE, the
+ * default is just to use PNG_LIBPNG_BUILD_BASE_TYPE.  Set this in CPPFLAGS
+ * with either:
+ *
+ *   -DPNG_RELEASE_BUILD Turns on the release compile path
+ *   -DPNG_RELEASE_BUILD=0 Turns it off
+ * or in your pngusr.h with
+ *   #define PNG_RELEASE_BUILD=1 Turns on the release compile path
+ *   #define PNG_RELEASE_BUILD=0 Turns it off
+ */
+#ifndef PNG_RELEASE_BUILD
+#  define PNG_RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
+#endif
+
+/* SECURITY and SAFETY:
+ *
+ * libpng is built with support for internal limits on image dimensions and
+ * memory usage.  These are documented in scripts/pnglibconf.dfa of the
+ * source and recorded in the machine generated header file pnglibconf.h.
+ */
+
+/* If you are running on a machine where you cannot allocate more
+ * than 64K of memory at once, uncomment this.  While libpng will not
+ * normally need that much memory in a chunk (unless you load up a very
+ * large file), zlib needs to know how big of a chunk it can use, and
+ * libpng thus makes sure to check any memory allocation to verify it
+ * will fit into memory.
+ *
+ * zlib provides 'MAXSEG_64K' which, if defined, indicates the
+ * same limit and pngconf.h (already included) sets the limit
+ * if certain operating systems are detected.
+ */
+#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
+#  define PNG_MAX_MALLOC_64K
+#endif
+
+#ifndef PNG_UNUSED
+/* Unused formal parameter warnings are silenced using the following macro
+ * which is expected to have no bad effects on performance (optimizing
+ * compilers will probably remove it entirely).  Note that if you replace
+ * it with something other than whitespace, you must include the terminating
+ * semicolon.
+ */
+#  define PNG_UNUSED(param) (void)param;
+#endif
+
+/* Just a little check that someone hasn't tried to define something
+ * contradictory.
+ */
+#if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
+#  undef PNG_ZBUF_SIZE
+#  define PNG_ZBUF_SIZE 65536L
+#endif
+
+/* If warnings or errors are turned off the code is disabled or redirected here.
+ * From 1.5.4 functions have been added to allow very limited formatting of
+ * error and warning messages - this code will also be disabled here.
+ */
+#ifdef PNG_WARNINGS_SUPPORTED
+#  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
+#else
+#  define png_warning_parameter(p,number,string) ((void)0)
+#  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
+#  define png_warning_parameter_signed(p,number,format,value) ((void)0)
+#  define png_formatted_warning(pp,p,message) ((void)(pp))
+#  define PNG_WARNING_PARAMETERS(p)
+#endif
+#ifndef PNG_ERROR_TEXT_SUPPORTED
+#  define png_fixed_error(s1,s2) png_err(s1)
+#endif
+
+/* Some fixed point APIs are still required even if not exported because
+ * they get used by the corresponding floating point APIs.  This magic
+ * deals with this:
+ */
+#ifdef PNG_FIXED_POINT_SUPPORTED
+#  define PNGFAPI PNGAPI
+#else
+#  define PNGFAPI /* PRIVATE */
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+/* Other defines specific to compilers can go here.  Try to keep
+ * them inside an appropriate ifdef/endif pair for portability.
+ */
+
+/* C allows up-casts from (void*) to any pointer and (const void*) to any
+ * pointer to a const object.  C++ regards this as a type error and requires an
+ * explicit, static, cast and provides the static_cast<> rune to ensure that
+ * const is not cast away.
+ */
+#ifdef __cplusplus
+#  define png_voidcast(type, value) static_cast<type>(value)
+#  define png_constcast(type, value) const_cast<type>(value)
+#  define png_aligncast(type, value) \
+   static_cast<type>(static_cast<void*>(value))
+#  define png_aligncastconst(type, value) \
+   static_cast<type>(static_cast<const void*>(value))
+#else
+#  define png_voidcast(type, value) (value)
+#  define png_constcast(type, value) ((type)(void*)(const void*)(value))
+#  define png_aligncast(type, value) ((void*)(value))
+#  define png_aligncastconst(type, value) ((const void*)(value))
+#endif /* __cplusplus */
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
+    defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+   /* png.c requires the following ANSI-C constants if the conversion of
+    * floating point to ASCII is implemented therein:
+    *
+    *  DBL_DIG  Maximum number of decimal digits (can be set to any constant)
+    *  DBL_MIN  Smallest normalized fp number (can be set to an arbitrary value)
+    *  DBL_MAX  Maximum floating point number (can be set to an arbitrary value)
+    */
+#  include <float.h>
+
+#  include <math.h>
+
+#  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
+   /* Amiga SAS/C: We must include builtin FPU functions when compiling using
+    * MATH=68881
+    */
+#    include <m68881.h>
+#  endif
+#endif
+
+/* This provides the non-ANSI (far) memory allocation routines. */
+#if defined(__TURBOC__) && defined(__MSDOS__)
+#  include <mem.h>
+#  include <alloc.h>
+#endif
+
+#if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
+    defined(_WIN32) || defined(__WIN32__)
+#  ifdef VBOX
+#   include <iprt/win/windows.h> /* defines _WINDOWS_ macro */
+#  else
+#  include <windows.h>  /* defines _WINDOWS_ macro */
+#  endif
+#endif
+#endif /* PNG_VERSION_INFO_ONLY */
+
+/* Moved here around 1.5.0beta36 from pngconf.h */
+/* Users may want to use these so they are not private.  Any library
+ * functions that are passed far data must be model-independent.
+ */
+
+/* Platform-independent functions */
+#ifndef PNG_ABORT
+#  define PNG_ABORT() abort()
+#endif
+
+/* These macros may need to be architecture dependent. */
+#define PNG_ALIGN_NONE      0 /* do not use data alignment */
+#define PNG_ALIGN_ALWAYS    1 /* assume unaligned accesses are OK */
+#ifdef offsetof
+#  define PNG_ALIGN_OFFSET  2 /* use offsetof to determine alignment */
+#else
+#  define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
+#endif
+#define PNG_ALIGN_SIZE      3 /* use sizeof to determine alignment */
+
+#ifndef PNG_ALIGN_TYPE
+   /* Default to using aligned access optimizations and requiring alignment to a
+    * multiple of the data type size.  Override in a compiler specific fashion
+    * if necessary by inserting tests here:
+    */
+#  define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
+#endif
+
+#if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
+   /* This is used because in some compiler implementations non-aligned
+    * structure members are supported, so the offsetof approach below fails.
+    * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
+    * is good for performance.  Do not do this unless you have tested the
+    * result and understand it.
+    */
+#  define png_alignof(type) (sizeof(type))
+#else
+#  if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
+#    define png_alignof(type) offsetof(struct{char c; type t;}, t)
+#  else
+#    if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
+#      define png_alignof(type) 1
+#    endif
+     /* Else leave png_alignof undefined to prevent use thereof */
+#  endif
+#endif
+
+/* This implicitly assumes alignment is always a multiple of 2. */
+#ifdef png_alignof
+#  define png_isaligned(ptr, type) \
+   (((type)(size_t)((const void*)(ptr)) & (type)(png_alignof(type)-1)) == 0)
+#else
+#  define png_isaligned(ptr, type) 0
+#endif
+
+/* End of memory model/platform independent support */
+/* End of 1.5.0beta36 move from pngconf.h */
+
+/* CONSTANTS and UTILITY MACROS
+ * These are used internally by libpng and not exposed in the API
+ */
+
+/* Various modes of operation.  Note that after an init, mode is set to
+ * zero automatically when the structure is created.  Three of these
+ * are defined in png.h because they need to be visible to applications
+ * that call png_set_unknown_chunk().
+ */
+/* #define PNG_HAVE_IHDR            0x01U (defined in png.h) */
+/* #define PNG_HAVE_PLTE            0x02U (defined in png.h) */
+#define PNG_HAVE_IDAT               0x04U
+/* #define PNG_AFTER_IDAT           0x08U (defined in png.h) */
+#define PNG_HAVE_IEND               0x10U
+                   /*               0x20U (unused) */
+                   /*               0x40U (unused) */
+                   /*               0x80U (unused) */
+#define PNG_HAVE_CHUNK_HEADER      0x100U
+#define PNG_WROTE_tIME             0x200U
+#define PNG_WROTE_INFO_BEFORE_PLTE 0x400U
+#define PNG_BACKGROUND_IS_GRAY     0x800U
+#define PNG_HAVE_PNG_SIGNATURE    0x1000U
+#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000U /* Have another chunk after IDAT */
+#define PNG_WROTE_eXIf            0x4000U
+#define PNG_IS_READ_STRUCT        0x8000U /* Else is a write struct */
+
+/* Flags for the transformations the PNG library does on the image data */
+#define PNG_BGR                 0x0001U
+#define PNG_INTERLACE           0x0002U
+#define PNG_PACK                0x0004U
+#define PNG_SHIFT               0x0008U
+#define PNG_SWAP_BYTES          0x0010U
+#define PNG_INVERT_MONO         0x0020U
+#define PNG_QUANTIZE            0x0040U
+#define PNG_COMPOSE             0x0080U    /* Was PNG_BACKGROUND */
+#define PNG_BACKGROUND_EXPAND   0x0100U
+#define PNG_EXPAND_16           0x0200U    /* Added to libpng 1.5.2 */
+#define PNG_16_TO_8             0x0400U    /* Becomes 'chop' in 1.5.4 */
+#define PNG_RGBA                0x0800U
+#define PNG_EXPAND              0x1000U
+#define PNG_GAMMA               0x2000U
+#define PNG_GRAY_TO_RGB         0x4000U
+#define PNG_FILLER              0x8000U
+#define PNG_PACKSWAP           0x10000U
+#define PNG_SWAP_ALPHA         0x20000U
+#define PNG_STRIP_ALPHA        0x40000U
+#define PNG_INVERT_ALPHA       0x80000U
+#define PNG_USER_TRANSFORM    0x100000U
+#define PNG_RGB_TO_GRAY_ERR   0x200000U
+#define PNG_RGB_TO_GRAY_WARN  0x400000U
+#define PNG_RGB_TO_GRAY       0x600000U /* two bits, RGB_TO_GRAY_ERR|WARN */
+#define PNG_ENCODE_ALPHA      0x800000U /* Added to libpng-1.5.4 */
+#define PNG_ADD_ALPHA        0x1000000U /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS      0x2000000U /* Added to libpng-1.2.9 */
+#define PNG_SCALE_16_TO_8    0x4000000U /* Added to libpng-1.5.4 */
+                       /*    0x8000000U unused */
+                       /*   0x10000000U unused */
+                       /*   0x20000000U unused */
+                       /*   0x40000000U unused */
+/* Flags for png_create_struct */
+#define PNG_STRUCT_PNG   0x0001U
+#define PNG_STRUCT_INFO  0x0002U
+
+/* Flags for the png_ptr->flags rather than declaring a byte for each one */
+#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001U
+#define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002U /* Added to libpng-1.6.0 */
+                                  /*      0x0004U    unused */
+#define PNG_FLAG_ZSTREAM_ENDED            0x0008U /* Added to libpng-1.6.0 */
+                                  /*      0x0010U    unused */
+                                  /*      0x0020U    unused */
+#define PNG_FLAG_ROW_INIT                 0x0040U
+#define PNG_FLAG_FILLER_AFTER             0x0080U
+#define PNG_FLAG_CRC_ANCILLARY_USE        0x0100U
+#define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200U
+#define PNG_FLAG_CRC_CRITICAL_USE         0x0400U
+#define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800U
+#define PNG_FLAG_ASSUME_sRGB              0x1000U /* Added to libpng-1.5.4 */
+#define PNG_FLAG_OPTIMIZE_ALPHA           0x2000U /* Added to libpng-1.5.4 */
+#define PNG_FLAG_DETECT_UNINITIALIZED     0x4000U /* Added to libpng-1.5.4 */
+/* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000U */
+/* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS      0x10000U */
+#define PNG_FLAG_LIBRARY_MISMATCH        0x20000U
+#define PNG_FLAG_STRIP_ERROR_NUMBERS     0x40000U
+#define PNG_FLAG_STRIP_ERROR_TEXT        0x80000U
+#define PNG_FLAG_BENIGN_ERRORS_WARN     0x100000U /* Added to libpng-1.4.0 */
+#define PNG_FLAG_APP_WARNINGS_WARN      0x200000U /* Added to libpng-1.6.0 */
+#define PNG_FLAG_APP_ERRORS_WARN        0x400000U /* Added to libpng-1.6.0 */
+                                  /*    0x800000U    unused */
+                                  /*   0x1000000U    unused */
+                                  /*   0x2000000U    unused */
+                                  /*   0x4000000U    unused */
+                                  /*   0x8000000U    unused */
+                                  /*  0x10000000U    unused */
+                                  /*  0x20000000U    unused */
+                                  /*  0x40000000U    unused */
+
+#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
+                                     PNG_FLAG_CRC_ANCILLARY_NOWARN)
+
+#define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
+                                     PNG_FLAG_CRC_CRITICAL_IGNORE)
+
+#define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
+                                     PNG_FLAG_CRC_CRITICAL_MASK)
+
+/* Save typing and make code easier to understand */
+
+#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
+   abs((int)((c1).green) - (int)((c2).green)) + \
+   abs((int)((c1).blue) - (int)((c2).blue)))
+
+/* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
+ * by dividing by 257 *with rounding*.  This macro is exact for the given range.
+ * See the discourse in pngrtran.c png_do_scale_16_to_8.  The values in the
+ * macro were established by experiment (modifying the added value).  The macro
+ * has a second variant that takes a value already scaled by 255 and divides by
+ * 65535 - this has a maximum error of .502.  Over the range 0..65535*65535 it
+ * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
+ */
+#define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
+#define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
+
+/* Added to libpng-1.2.6 JB */
+#define PNG_ROWBYTES(pixel_bits, width) \
+    ((pixel_bits) >= 8 ? \
+    ((size_t)(width) * (((size_t)(pixel_bits)) >> 3)) : \
+    (( ((size_t)(width) * ((size_t)(pixel_bits))) + 7) >> 3) )
+
+/* This returns the number of trailing bits in the last byte of a row, 0 if the
+ * last byte is completely full of pixels.  It is, in principle, (pixel_bits x
+ * width) % 8, but that would overflow for large 'width'.  The second macro is
+ * the same except that it returns the number of unused bits in the last byte;
+ * (8-TRAILBITS), but 0 when TRAILBITS is 0.
+ *
+ * NOTE: these macros are intended to be self-evidently correct and never
+ * overflow on the assumption that pixel_bits is in the range 0..255.  The
+ * arguments are evaluated only once and they can be signed (e.g. as a result of
+ * the integral promotions).  The result of the expression always has type
+ * (png_uint_32), however the compiler always knows it is in the range 0..7.
+ */
+#define PNG_TRAILBITS(pixel_bits, width) \
+    (((pixel_bits) * ((width) % (png_uint_32)8)) % 8)
+
+#define PNG_PADBITS(pixel_bits, width) \
+    ((8 - PNG_TRAILBITS(pixel_bits, width)) % 8)
+
+/* PNG_OUT_OF_RANGE returns true if value is outside the range
+ * ideal-delta..ideal+delta.  Each argument is evaluated twice.
+ * "ideal" and "delta" should be constants, normally simple
+ * integers, "value" a variable. Added to libpng-1.2.6 JB
+ */
+#define PNG_OUT_OF_RANGE(value, ideal, delta) \
+   ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
+
+/* Conversions between fixed and floating point, only defined if
+ * required (to make sure the code doesn't accidentally use float
+ * when it is supposedly disabled.)
+ */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+/* The floating point conversion can't overflow, though it can and
+ * does lose accuracy relative to the original fixed point value.
+ * In practice this doesn't matter because png_fixed_point only
+ * stores numbers with very low precision.  The png_ptr and s
+ * arguments are unused by default but are there in case error
+ * checking becomes a requirement.
+ */
+#define png_float(png_ptr, fixed, s) (.00001 * (fixed))
+
+/* The fixed point conversion performs range checking and evaluates
+ * its argument multiple times, so must be used with care.  The
+ * range checking uses the PNG specification values for a signed
+ * 32-bit fixed point value except that the values are deliberately
+ * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
+ * (2^31-1) * 100000). 's' is a string that describes the value being
+ * converted.
+ *
+ * NOTE: this macro will raise a png_error if the range check fails,
+ * therefore it is normally only appropriate to use this on values
+ * that come from API calls or other sources where an out of range
+ * error indicates a programming error, not a data error!
+ *
+ * NOTE: by default this is off - the macro is not used - because the
+ * function call saves a lot of code.
+ */
+#ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
+#define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
+    ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
+#endif
+/* else the corresponding function is defined below, inside the scope of the
+ * cplusplus test.
+ */
+#endif
+
+/* Constants for known chunk types.  If you need to add a chunk, define the name
+ * here.  For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case.  Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.
+ *
+ * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
+ * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
+ * to be generated if required.
+ *
+ * PNG_32b correctly produces a value shifted by up to 24 bits, even on
+ * architectures where (int) is only 16 bits.
+ */
+#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
+#define PNG_U32(b1,b2,b3,b4) \
+   (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
+
+/* Constants for known chunk types.
+ *
+ * MAINTAINERS: If you need to add a chunk, define the name here.
+ * For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case.  Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.  Please keep the list sorted.
+ *
+ * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
+ * type.  In fact the specification does not express chunk types this way,
+ * however using a 32-bit value means that the chunk type can be read from the
+ * stream using exactly the same code as used for a 32-bit unsigned value and
+ * can be examined far more efficiently (using one arithmetic compare).
+ *
+ * Prior to 1.5.6 the chunk type constants were expressed as C strings.  The
+ * libpng API still uses strings for 'unknown' chunks and a macro,
+ * PNG_STRING_FROM_CHUNK, allows a string to be generated if required.  Notice
+ * that for portable code numeric values must still be used; the string "IHDR"
+ * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
+ *
+ * In 1.7.0 the definitions will be made public in png.h to avoid having to
+ * duplicate the same definitions in application code.
+ */
+#define png_IDAT PNG_U32( 73,  68,  65,  84)
+#define png_IEND PNG_U32( 73,  69,  78,  68)
+#define png_IHDR PNG_U32( 73,  72,  68,  82)
+#define png_PLTE PNG_U32( 80,  76,  84,  69)
+#define png_bKGD PNG_U32( 98,  75,  71,  68)
+#define png_cHRM PNG_U32( 99,  72,  82,  77)
+#define png_eXIf PNG_U32(101,  88,  73, 102) /* registered July 2017 */
+#define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
+#define png_gAMA PNG_U32(103,  65,  77,  65)
+#define png_gIFg PNG_U32(103,  73,  70, 103)
+#define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
+#define png_gIFx PNG_U32(103,  73,  70, 120)
+#define png_hIST PNG_U32(104,  73,  83,  84)
+#define png_iCCP PNG_U32(105,  67,  67,  80)
+#define png_iTXt PNG_U32(105,  84,  88, 116)
+#define png_oFFs PNG_U32(111,  70,  70, 115)
+#define png_pCAL PNG_U32(112,  67,  65,  76)
+#define png_pHYs PNG_U32(112,  72,  89, 115)
+#define png_sBIT PNG_U32(115,  66,  73,  84)
+#define png_sCAL PNG_U32(115,  67,  65,  76)
+#define png_sPLT PNG_U32(115,  80,  76,  84)
+#define png_sRGB PNG_U32(115,  82,  71,  66)
+#define png_sTER PNG_U32(115,  84,  69,  82)
+#define png_tEXt PNG_U32(116,  69,  88, 116)
+#define png_tIME PNG_U32(116,  73,  77,  69)
+#define png_tRNS PNG_U32(116,  82,  78,  83)
+#define png_zTXt PNG_U32(122,  84,  88, 116)
+
+/* The following will work on (signed char*) strings, whereas the get_uint_32
+ * macro will fail on top-bit-set values because of the sign extension.
+ */
+#define PNG_CHUNK_FROM_STRING(s)\
+   PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])
+
+/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
+ * signed and the argument is a (char[])  This macro will fail miserably on
+ * systems where (char) is more than 8 bits.
+ */
+#define PNG_STRING_FROM_CHUNK(s,c)\
+   (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
+   ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
+   ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
+   ((char*)(s))[3]=(char)((c & 0xff)))
+
+/* Do the same but terminate with a null character. */
+#define PNG_CSTRING_FROM_CHUNK(s,c)\
+   (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
+
+/* Test on flag values as defined in the spec (section 5.4): */
+#define PNG_CHUNK_ANCILLARY(c)   (1 & ((c) >> 29))
+#define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
+#define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
+#define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
+#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
+
+/* Gamma values (new at libpng-1.5.4): */
+#define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
+#define PNG_GAMMA_MAC_INVERSE 65909
+#define PNG_GAMMA_sRGB_INVERSE 45455
+
+/* Almost everything below is C specific; the #defines above can be used in
+ * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
+ */
+#ifndef PNG_VERSION_INFO_ONLY
+
+#include "pngstruct.h"
+#include "pnginfo.h"
+
+/* Validate the include paths - the include path used to generate pnglibconf.h
+ * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
+ */
+#if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
+#  error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
+      "-I (include path) error: see the notes in pngpriv.h"
+   /* This means that when pnglibconf.h was built the copy of zlib.h that it
+    * used is not the same as the one being used here.  Because the build of
+    * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
+    * zlib version number and because this affects handling of certain broken
+    * PNG files the -I directives must match.
+    *
+    * The most likely explanation is that you passed a -I in CFLAGS. This will
+    * not work; all the preprocessor directives and in particular all the -I
+    * directives must be in CPPFLAGS.
+    */
+#endif
+
+/* This is used for 16-bit gamma tables -- only the top level pointers are
+ * const; this could be changed:
+ */
+typedef const png_uint_16p * png_const_uint_16pp;
+
+/* Added to libpng-1.5.7: sRGB conversion tables */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
+   /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
+    * 0..65535.  This table gives the closest 16-bit answers (no errors).
+    */
+#endif
+
+PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
+PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
+
+#define PNG_sRGB_FROM_LINEAR(linear) \
+  ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
+   + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
+   /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
+    * encoded value with maximum error 0.646365.  Note that the input is not a
+    * 16-bit value; it has been multiplied by 255! */
+#endif /* SIMPLIFIED_READ/WRITE */
+
+
+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* Internal functions; these are not exported from a DLL however because they
+ * are used within several of the C source files they have to be C extern.
+ *
+ * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
+ */
+
+/* Zlib support */
+#define PNG_UNEXPECTED_ZLIB_RETURN (-7)
+PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
+   PNG_EMPTY);
+   /* Used by the zlib handling functions to ensure that z_stream::msg is always
+    * set before they return.
+    */
+
+#ifdef PNG_WRITE_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
+   png_compression_bufferp *list),PNG_EMPTY);
+   /* Free the buffer list used by the compressed write code. */
+#endif
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
+   !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
+   (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
+   defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
+   (defined(PNG_sCAL_SUPPORTED) && \
+   defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
+   double fp, png_const_charp text),PNG_EMPTY);
+#endif
+
+/* Check the user version string for compatibility, returns false if the version
+ * numbers aren't compatible.
+ */
+PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
+   png_const_charp user_png_ver),PNG_EMPTY);
+
+/* Internal base allocator - no messages, NULL on failure to allocate.  This
+ * does, however, call the application provided allocator and that could call
+ * png_error (although that would be a bug in the application implementation.)
+ */
+PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
+   png_alloc_size_t size),PNG_ALLOCATED);
+
+#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
+   defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
+/* Internal array allocator, outputs no error or warning messages on failure,
+ * just returns NULL.
+ */
+PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
+   int nelements, size_t element_size),PNG_ALLOCATED);
+
+/* The same but an existing array is extended by add_elements.  This function
+ * also memsets the new elements to 0 and copies the old elements.  The old
+ * array is not freed or altered.
+ */
+PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
+   png_const_voidp array, int old_elements, int add_elements,
+   size_t element_size),PNG_ALLOCATED);
+#endif /* text, sPLT or unknown chunks */
+
+/* Magic to create a struct when there is no struct to call the user supplied
+ * memory allocators.  Because error handling has not been set up the memory
+ * handlers can't safely call png_error, but this is an obscure and undocumented
+ * restriction so libpng has to assume that the 'free' handler, at least, might
+ * call png_error.
+ */
+PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
+   (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+    png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
+    png_free_ptr free_fn),PNG_ALLOCATED);
+
+/* Free memory from internal libpng struct */
+PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
+   PNG_EMPTY);
+
+/* Free an allocated jmp_buf (always succeeds) */
+PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
+
+/* Function to allocate memory for zlib.  PNGAPI is disallowed. */
+PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
+   PNG_ALLOCATED);
+
+/* Function to free memory for zlib.  PNGAPI is disallowed. */
+PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
+
+/* Next four functions are used internally as callbacks.  PNGCBAPI is required
+ * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3, changed to
+ * PNGCBAPI at 1.5.0
+ */
+
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
+    png_bytep data, size_t length),PNG_EMPTY);
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
+    png_bytep buffer, size_t length),PNG_EMPTY);
+#endif
+
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
+    png_bytep data, size_t length),PNG_EMPTY);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+#  ifdef PNG_STDIO_SUPPORTED
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
+   PNG_EMPTY);
+#  endif
+#endif
+
+/* Reset the CRC variable */
+PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
+
+/* Write the "data" buffer to whatever output you are using */
+PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
+    png_const_bytep data, size_t length),PNG_EMPTY);
+
+/* Read and check the PNG file signature */
+PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
+   png_inforp info_ptr),PNG_EMPTY);
+
+/* Read the chunk header (length + type name) */
+PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
+   PNG_EMPTY);
+
+/* Read data from whatever input you are using into the "data" buffer */
+PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
+    size_t length),PNG_EMPTY);
+
+/* Read bytes into buf, and update png_ptr->crc */
+PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
+    png_uint_32 length),PNG_EMPTY);
+
+/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
+PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
+   png_uint_32 skip),PNG_EMPTY);
+
+/* Read the CRC from the file and compare it to the libpng calculated CRC */
+PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
+
+/* Calculate the CRC over a section of data.  Note that we are only
+ * passing a maximum of 64K on systems that have this as a memory limit,
+ * since this is the maximum buffer size we can specify.
+ */
+PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
+   png_const_bytep ptr, size_t length),PNG_EMPTY);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
+#endif
+
+/* Write various chunks */
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information.
+ */
+PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
+   png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
+   int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
+   png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
+   png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
+   PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
+
+#ifdef PNG_WRITE_gAMA_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
+    png_fixed_point file_gamma),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
+    png_const_color_8p sbit, int color_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_cHRM_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
+    const png_xy *xy), PNG_EMPTY);
+   /* The xy value must have been previously validated */
+#endif
+
+#ifdef PNG_WRITE_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
+    int intent),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_eXIf_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_eXIf,(png_structrp png_ptr,
+    png_bytep exif, int num_exif),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
+   png_const_charp name, png_const_bytep profile), PNG_EMPTY);
+   /* The profile must have been previously validated for correctness, the
+    * length comes from the first four bytes.  Only the base, deflate,
+    * compression is supported.
+    */
+#endif
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
+    png_const_sPLT_tp palette),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
+    png_const_bytep trans, png_const_color_16p values, int number,
+    int color_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
+    png_const_color_16p values, int color_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
+    png_const_uint_16p hist, int num_hist),PNG_EMPTY);
+#endif
+
+/* Chunks that have keywords */
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
+   png_const_charp key, png_const_charp text, size_t text_len),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
+    key, png_const_charp text, int compression),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
+    int compression, png_const_charp key, png_const_charp lang,
+    png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED  /* Added at version 1.0.14 and 1.2.4 */
+PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
+    png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
+    png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
+    png_const_charp units, png_charpp params),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
+    png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
+    int unit_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
+    png_const_timep mod_time),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
+    int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
+#endif
+
+/* Called when finished processing a row of data */
+PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
+    PNG_EMPTY);
+
+/* Internal use only.   Called before first row of data */
+PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
+    PNG_EMPTY);
+
+/* Combine a row of data, dealing with alpha, etc. if requested.  'row' is an
+ * array of png_ptr->width pixels.  If the image is not interlaced or this
+ * is the final pass this just does a memcpy, otherwise the "display" flag
+ * is used to determine whether to copy pixels that are not in the current pass.
+ *
+ * Because 'png_do_read_interlace' (below) replicates pixels this allows this
+ * function to achieve the documented 'blocky' appearance during interlaced read
+ * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
+ * are not changed if they are not in the current pass, when display is 0.
+ *
+ * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
+ *
+ * The API always reads from the png_struct row buffer and always assumes that
+ * it is full width (png_do_read_interlace has already been called.)
+ *
+ * This function is only ever used to write to row buffers provided by the
+ * caller of the relevant libpng API and the row must have already been
+ * transformed by the read transformations.
+ *
+ * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
+ * bitmasks for use within the code, otherwise runtime generated masks are used.
+ * The default is compile time masks.
+ */
+#ifndef PNG_USE_COMPILE_TIME_MASKS
+#  define PNG_USE_COMPILE_TIME_MASKS 1
+#endif
+PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
+    png_bytep row, int display),PNG_EMPTY);
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* Expand an interlaced row: the 'row_info' describes the pass data that has
+ * been read in and must correspond to the pixels in 'row', the pixels are
+ * expanded (moved apart) in 'row' to match the final layout, when doing this
+ * the pixels are *replicated* to the intervening space.  This is essential for
+ * the correct operation of png_combine_row, above.
+ */
+PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
+    png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
+#endif
+
+/* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+/* Grab pixels out of a row for an interlaced pass */
+PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
+    png_bytep row, int pass),PNG_EMPTY);
+#endif
+
+/* Unfilter a row: check the filter value before calling this, there is no point
+ * calling it for PNG_FILTER_VALUE_NONE.
+ */
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
+
+#if PNG_ARM_NEON_OPT > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
+    png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+#if PNG_MIPS_MSA_IMPLEMENTATION == 1
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_msa,(png_row_infop row_info,
+    png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_msa,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+#if PNG_MIPS_MMI_IMPLEMENTATION > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_mmi,(png_row_infop row_info,
+    png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_mmi,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_mmi,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_mmi,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_mmi,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_mmi,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_mmi,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+#if PNG_POWERPC_VSX_OPT > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_vsx,(png_row_infop row_info,
+    png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_vsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+#if PNG_INTEL_SSE_IMPLEMENTATION > 0
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_sse2,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+#if PNG_LOONGARCH_LSX_IMPLEMENTATION == 1
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_lsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_lsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_lsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_lsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_lsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_lsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_lsx,(png_row_infop
+    row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+#endif
+
+/* Choose the best filter to use and filter the row data */
+PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
+    png_row_infop row_info),PNG_EMPTY);
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
+   png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
+   /* Read 'avail_out' bytes of data from the IDAT stream.  If the output buffer
+    * is NULL the function checks, instead, for the end of the stream.  In this
+    * case a benign error will be issued if the stream end is not found or if
+    * extra data has to be consumed.
+    */
+PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
+   PNG_EMPTY);
+   /* This cleans up when the IDAT LZ stream does not end when the last image
+    * byte is read; there is still some pending input.
+    */
+
+PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
+   PNG_EMPTY);
+   /* Finish a row while reading, dealing with interlacing passes, etc. */
+#endif /* SEQUENTIAL_READ */
+
+/* Initialize the row buffers, etc. */
+PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
+
+#if ZLIB_VERNUM >= 0x1240
+PNG_INTERNAL_FUNCTION(int,png_zlib_inflate,(png_structrp png_ptr, int flush),
+      PNG_EMPTY);
+#  define PNG_INFLATE(pp, flush) png_zlib_inflate(pp, flush)
+#else /* Zlib < 1.2.4 */
+#  define PNG_INFLATE(pp, flush) inflate(&(pp)->zstream, flush)
+#endif /* Zlib < 1.2.4 */
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Optional call to update the users info structure */
+PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+#endif
+
+/* Shared transform functions, defined in pngtran.c */
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
+    png_bytep row, int at_start),PNG_EMPTY);
+#endif
+
+#ifdef PNG_16BIT_SUPPORTED
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
+    png_bytep row),PNG_EMPTY);
+#endif
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
+    defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
+    png_bytep row),PNG_EMPTY);
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
+    png_bytep row),PNG_EMPTY);
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
+    png_bytep row),PNG_EMPTY);
+#endif
+
+/* The following decodes the appropriate chunks, and does error correction,
+ * then calls the appropriate callback for the chunk if it is valid.
+ */
+
+/* Decode the IHDR chunk */
+PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_eXIf_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_eXIf,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif /* READ_iCCP */
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif /* READ_sPLT */
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_const_structrp png_ptr,
+    png_uint_32 chunk_name),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_check_chunk_length,(png_const_structrp png_ptr,
+    png_uint_32 chunk_length),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
+   /* This is the function that gets called for unknown chunks.  The 'keep'
+    * argument is either non-zero for a known chunk that has been set to be
+    * handled as unknown or zero for an unknown chunk.  By default the function
+    * just skips the chunk or errors out if it is critical.
+    */
+
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
+    defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
+    (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
+   /* Exactly as the API png_handle_as_unknown() except that the argument is a
+    * 32-bit chunk name, not a string.
+    */
+#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
+
+/* Handle the transformations for reading and writing */
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
+   png_row_infop row_info),PNG_EMPTY);
+#endif
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
+   png_row_infop row_info),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
+    PNG_EMPTY);
+#endif
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
+    PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
+    png_bytep buffer, size_t buffer_length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
+    png_bytep buffer, size_t buffer_length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
+    PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
+   png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
+   png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
+   png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
+    png_bytep row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
+    PNG_EMPTY);
+#  ifdef PNG_READ_tEXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+#  endif
+#  ifdef PNG_READ_zTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+#  endif
+#  ifdef PNG_READ_iTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
+    png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
+    png_inforp info_ptr),PNG_EMPTY);
+#  endif
+
+#endif /* PROGRESSIVE_READ */
+
+/* Added at libpng version 1.6.0 */
+#ifdef PNG_GAMMA_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
+    png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
+   /* Set the colorspace gamma with a value provided by the application or by
+    * the gAMA chunk on read.  The value will override anything set by an ICC
+    * profile.
+    */
+
+PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
+    png_inforp info_ptr), PNG_EMPTY);
+   /* Synchronize the info 'valid' flags with the colorspace */
+
+PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
+    png_inforp info_ptr), PNG_EMPTY);
+   /* Copy the png_struct colorspace to the info_struct and call the above to
+    * synchronize the flags.  Checks for NULL info_ptr and does nothing.
+    */
+#endif
+
+/* Added at libpng version 1.4.0 */
+#ifdef PNG_COLORSPACE_SUPPORTED
+/* These internal functions are for maintaining the colorspace structure within
+ * a png_info or png_struct (or, indeed, both).
+ */
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
+   (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
+    int preferred), PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
+   (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
+    int preferred), PNG_EMPTY);
+
+#ifdef PNG_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, int intent), PNG_EMPTY);
+   /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
+    * flags to write them, if it returns false there was a problem and an error
+    * message has already been output (but the colorspace may still need to be
+    * synced to record the invalid flag).
+    */
+#endif /* sRGB */
+
+#ifdef PNG_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, png_const_charp name,
+   png_uint_32 profile_length, png_const_bytep profile, int color_type),
+   PNG_EMPTY);
+   /* The 'name' is used for information only */
+
+/* Routines for checking parts of an ICC profile. */
+#ifdef PNG_READ_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, png_const_charp name,
+   png_uint_32 profile_length), PNG_EMPTY);
+#endif /* READ_iCCP */
+PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, png_const_charp name,
+   png_uint_32 profile_length,
+   png_const_bytep profile /* first 132 bytes only */, int color_type),
+   PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
+   png_colorspacerp colorspace, png_const_charp name,
+   png_uint_32 profile_length,
+   png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
+#ifdef PNG_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
+   png_const_structrp png_ptr, png_colorspacerp colorspace,
+   png_const_bytep profile, uLong adler), PNG_EMPTY);
+   /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
+    * be zero to indicate that it is not available.  It is used, if provided,
+    * as a fast check on the profile when checking to see if it is sRGB.
+    */
+#endif
+#endif /* iCCP */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
+   (png_structrp png_ptr), PNG_EMPTY);
+   /* Set the rgb_to_gray coefficients from the colorspace Y values */
+#endif /* READ_RGB_TO_GRAY */
+#endif /* COLORSPACE */
+
+/* Added at libpng version 1.4.0 */
+PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
+    png_uint_32 width, png_uint_32 height, int bit_depth,
+    int color_type, int interlace_type, int compression_type,
+    int filter_type),PNG_EMPTY);
+
+/* Added at libpng version 1.5.10 */
+#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
+    defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
+   (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
+#endif
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
+   png_const_charp name),PNG_NORETURN);
+#endif
+
+/* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
+ * the end.  Always leaves the buffer nul terminated.  Never errors out (and
+ * there is no error code.)
+ */
+PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
+   size_t pos, png_const_charp string),PNG_EMPTY);
+
+/* Various internal functions to handle formatted warning messages, currently
+ * only implemented for warnings.
+ */
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string.  This utility only
+ * does unsigned values.
+ */
+PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
+   png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
+
+/* Convenience macro that takes an array: */
+#define PNG_FORMAT_NUMBER(buffer,format,number) \
+   png_format_number(buffer, buffer + (sizeof buffer), format, number)
+
+/* Suggested size for a number buffer (enough for 64 bits and a sign!) */
+#define PNG_NUMBER_BUFFER_SIZE 24
+
+/* These are the integer formats currently supported, the name is formed from
+ * the standard printf(3) format string.
+ */
+#define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
+#define PNG_NUMBER_FORMAT_02u   2
+#define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
+#define PNG_NUMBER_FORMAT_02d   2
+#define PNG_NUMBER_FORMAT_x     3
+#define PNG_NUMBER_FORMAT_02x   4
+#define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* New defines and members adding in libpng-1.5.4 */
+#  define PNG_WARNING_PARAMETER_SIZE 32
+#  define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
+
+/* An l-value of this type has to be passed to the APIs below to cache the
+ * values of the parameters to a formatted warning message.
+ */
+typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
+   PNG_WARNING_PARAMETER_SIZE];
+
+PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
+   int number, png_const_charp string),PNG_EMPTY);
+   /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
+    * including the trailing '\0'.
+    */
+PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
+   (png_warning_parameters p, int number, int format, png_alloc_size_t value),
+   PNG_EMPTY);
+   /* Use png_alloc_size_t because it is an unsigned type as big as any we
+    * need to output.  Use the following for a signed value.
+    */
+PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
+   (png_warning_parameters p, int number, int format, png_int_32 value),
+   PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
+   png_warning_parameters p, png_const_charp message),PNG_EMPTY);
+   /* 'message' follows the X/Open approach of using @1, @2 to insert
+    * parameters previously supplied using the above functions.  Errors in
+    * specifying the parameters will simply result in garbage substitutions.
+    */
+#endif
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+/* Application errors (new in 1.6); use these functions (declared below) for
+ * errors in the parameters or order of API function calls on read.  The
+ * 'warning' should be used for an error that can be handled completely; the
+ * 'error' for one which can be handled safely but which may lose application
+ * information or settings.
+ *
+ * By default these both result in a png_error call prior to release, while in a
+ * released version the 'warning' is just a warning.  However if the application
+ * explicitly disables benign errors (explicitly permitting the code to lose
+ * information) they both turn into warnings.
+ *
+ * If benign errors aren't supported they end up as the corresponding base call
+ * (png_warning or png_error.)
+ */
+PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
+   png_const_charp message),PNG_EMPTY);
+   /* The application provided invalid parameters to an API function or called
+    * an API function at the wrong time, libpng can completely recover.
+    */
+
+PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
+   png_const_charp message),PNG_EMPTY);
+   /* As above but libpng will ignore the call, or attempt some other partial
+    * recovery from the error.
+    */
+#else
+#  define png_app_warning(pp,s) png_warning(pp,s)
+#  define png_app_error(pp,s) png_error(pp,s)
+#endif
+
+PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
+   png_const_charp message, int error),PNG_EMPTY);
+   /* Report a recoverable issue in chunk data.  On read this is used to report
+    * a problem found while reading a particular chunk and the
+    * png_chunk_benign_error or png_chunk_warning function is used as
+    * appropriate.  On write this is used to report an error that comes from
+    * data set via an application call to a png_set_ API and png_app_error or
+    * png_app_warning is used as appropriate.
+    *
+    * The 'error' parameter must have one of the following values:
+    */
+#define PNG_CHUNK_WARNING     0 /* never an error */
+#define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
+#define PNG_CHUNK_ERROR       2 /* always an error */
+
+/* ASCII to FP interfaces, currently only implemented if sCAL
+ * support is required.
+ */
+#if defined(PNG_sCAL_SUPPORTED)
+/* MAX_DIGITS is actually the maximum number of characters in an sCAL
+ * width or height, derived from the precision (number of significant
+ * digits - a build time settable option) and assumptions about the
+ * maximum ridiculous exponent.
+ */
+#define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
+   png_charp ascii, size_t size, double fp, unsigned int precision),
+   PNG_EMPTY);
+#endif /* FLOATING_POINT */
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
+   png_charp ascii, size_t size, png_fixed_point fp),PNG_EMPTY);
+#endif /* FIXED_POINT */
+#endif /* sCAL */
+
+#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
+/* An internal API to validate the format of a floating point number.
+ * The result is the index of the next character.  If the number is
+ * not valid it will be the index of a character in the supposed number.
+ *
+ * The format of a number is defined in the PNG extensions specification
+ * and this API is strictly conformant to that spec, not anyone elses!
+ *
+ * The format as a regular expression is:
+ *
+ * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
+ *
+ * or:
+ *
+ * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
+ *
+ * The complexity is that either integer or fraction must be present and the
+ * fraction is permitted to have no digits only if the integer is present.
+ *
+ * NOTE: The dangling E problem.
+ *   There is a PNG valid floating point number in the following:
+ *
+ *       PNG floating point numbers are not greedy.
+ *
+ *   Working this out requires *TWO* character lookahead (because of the
+ *   sign), the parser does not do this - it will fail at the 'r' - this
+ *   doesn't matter for PNG sCAL chunk values, but it requires more care
+ *   if the value were ever to be embedded in something more complex.  Use
+ *   ANSI-C strtod if you need the lookahead.
+ */
+/* State table for the parser. */
+#define PNG_FP_INTEGER    0  /* before or in integer */
+#define PNG_FP_FRACTION   1  /* before or in fraction */
+#define PNG_FP_EXPONENT   2  /* before or in exponent */
+#define PNG_FP_STATE      3  /* mask for the above */
+#define PNG_FP_SAW_SIGN   4  /* Saw +/- in current state */
+#define PNG_FP_SAW_DIGIT  8  /* Saw a digit in current state */
+#define PNG_FP_SAW_DOT   16  /* Saw a dot in current state */
+#define PNG_FP_SAW_E     32  /* Saw an E (or e) in current state */
+#define PNG_FP_SAW_ANY   60  /* Saw any of the above 4 */
+
+/* These three values don't affect the parser.  They are set but not used.
+ */
+#define PNG_FP_WAS_VALID 64  /* Preceding substring is a valid fp number */
+#define PNG_FP_NEGATIVE 128  /* A negative number, including "-0" */
+#define PNG_FP_NONZERO  256  /* A non-zero value */
+#define PNG_FP_STICKY   448  /* The above three flags */
+
+/* This is available for the caller to store in 'state' if required.  Do not
+ * call the parser after setting it (the parser sometimes clears it.)
+ */
+#define PNG_FP_INVALID  512  /* Available for callers as a distinct value */
+
+/* Result codes for the parser (boolean - true means ok, false means
+ * not ok yet.)
+ */
+#define PNG_FP_MAYBE      0  /* The number may be valid in the future */
+#define PNG_FP_OK         1  /* The number is valid */
+
+/* Tests on the sticky non-zero and negative flags.  To pass these checks
+ * the state must also indicate that the whole number is valid - this is
+ * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
+ * is equivalent to PNG_FP_OK above.)
+ */
+#define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
+   /* NZ_MASK: the string is valid and a non-zero negative value */
+#define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
+   /* Z MASK: the string is valid and a non-zero value. */
+   /* PNG_FP_SAW_DIGIT: the string is valid. */
+#define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
+#define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
+#define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
+
+/* The actual parser.  This can be called repeatedly. It updates
+ * the index into the string and the state variable (which must
+ * be initialized to 0).  It returns a result code, as above.  There
+ * is no point calling the parser any more if it fails to advance to
+ * the end of the string - it is stuck on an invalid character (or
+ * terminated by '\0').
+ *
+ * Note that the pointer will consume an E or even an E+ and then leave
+ * a 'maybe' state even though a preceding integer.fraction is valid.
+ * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
+ * a valid number.  It's possible to recover from this by calling
+ * the parser again (from the start, with state 0) but with a string
+ * that omits the last character (i.e. set the size to the index of
+ * the problem character.)  This has not been tested within libpng.
+ */
+PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
+   size_t size, int *statep, size_t *whereami),PNG_EMPTY);
+
+/* This is the same but it checks a complete string and returns true
+ * only if it just contains a floating point number.  As of 1.5.4 this
+ * function also returns the state at the end of parsing the number if
+ * it was valid (otherwise it returns 0.)  This can be used for testing
+ * for negative or zero values using the sticky flag.
+ */
+PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
+   size_t size),PNG_EMPTY);
+#endif /* pCAL || sCAL */
+
+#if defined(PNG_GAMMA_SUPPORTED) ||\
+    defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
+/* Added at libpng version 1.5.0 */
+/* This is a utility to provide a*times/div (rounded) and indicate
+ * if there is an overflow.  The result is a boolean - false (0)
+ * for overflow, true (1) if no overflow, in which case *res
+ * holds the result.
+ */
+PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
+   png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+/* Same deal, but issue a warning on overflow and return 0. */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
+   (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
+   png_int_32 divided_by),PNG_EMPTY);
+#endif
+
+#ifdef PNG_GAMMA_SUPPORTED
+/* Calculate a reciprocal - used for gamma values.  This returns
+ * 0 if the argument is 0 in order to maintain an undefined value;
+ * there are no warnings.
+ */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
+   PNG_EMPTY);
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* The same but gives a reciprocal of the product of two fixed point
+ * values.  Accuracy is suitable for gamma calculations but this is
+ * not exact - use png_muldiv for that.  Only required at present on read.
+ */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
+   png_fixed_point b),PNG_EMPTY);
+#endif
+
+/* Return true if the gamma value is significantly different from 1.0 */
+PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
+   PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Internal fixed point gamma correction.  These APIs are called as
+ * required to convert single values - they don't need to be fast,
+ * they are not used when processing image pixel values.
+ *
+ * While the input is an 'unsigned' value it must actually be the
+ * correct bit value - 0..255 or 0..65535 as required.
+ */
+PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
+   unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
+   png_fixed_point gamma_value),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
+   png_fixed_point gamma_value),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
+   PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
+   int bit_depth),PNG_EMPTY);
+#endif
+
+/* SIMPLIFIED READ/WRITE SUPPORT */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+   defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+/* The internal structure that png_image::opaque points to. */
+typedef struct png_control
+{
+   png_structp png_ptr;
+   png_infop   info_ptr;
+   png_voidp   error_buf;           /* Always a jmp_buf at present. */
+
+   png_const_bytep memory;          /* Memory buffer. */
+   size_t          size;            /* Size of the memory buffer. */
+
+   unsigned int for_write       :1; /* Otherwise it is a read structure */
+   unsigned int owned_file      :1; /* We own the file in io_ptr */
+} png_control;
+
+/* Return the pointer to the jmp_buf from a png_control: necessary because C
+ * does not reveal the type of the elements of jmp_buf.
+ */
+#ifdef __cplusplus
+#  define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
+#else
+#  define png_control_jmp_buf(pc) ((pc)->error_buf)
+#endif
+
+/* Utility to safely execute a piece of libpng code catching and logging any
+ * errors that might occur.  Returns true on success, false on failure (either
+ * of the function or as a result of a png_error.)
+ */
+PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
+   png_const_charp error_message),PNG_NORETURN);
+
+#ifdef PNG_WARNINGS_SUPPORTED
+PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
+   png_const_charp warning_message),PNG_EMPTY);
+#else
+#  define png_safe_warning 0/*dummy argument*/
+#endif
+
+PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
+   int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
+
+/* Utility to log an error; this also cleans up the png_image; the function
+ * always returns 0 (false).
+ */
+PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
+   png_const_charp error_message),PNG_EMPTY);
+
+#ifndef PNG_SIMPLIFIED_READ_SUPPORTED
+/* png_image_free is used by the write code but not exported */
+PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
+#endif /* !SIMPLIFIED_READ */
+
+#endif /* SIMPLIFIED READ/WRITE */
+
+/* These are initialization functions for hardware specific PNG filter
+ * optimizations; list these here then select the appropriate one at compile
+ * time using the macro PNG_FILTER_OPTIMIZATIONS.  If the macro is not defined
+ * the generic code is used.
+ */
+#ifdef PNG_FILTER_OPTIMIZATIONS
+PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
+   unsigned int bpp), PNG_EMPTY);
+   /* Just declare the optimization that will be used */
+#else
+   /* List *all* the possible optimizations here - this branch is required if
+    * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
+    * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
+    */
+#  if PNG_ARM_NEON_OPT > 0
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
+   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#endif
+
+#if PNG_MIPS_MSA_IMPLEMENTATION == 1
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_mips,
+   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#endif
+
+#  if PNG_MIPS_MMI_IMPLEMENTATION > 0
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_mips,
+   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#  endif
+
+#  if PNG_INTEL_SSE_IMPLEMENTATION > 0
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_sse2,
+   (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#  endif
+#endif
+
+#if PNG_LOONGARCH_LSX_OPT > 0
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_lsx,
+    (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#endif
+
+PNG_INTERNAL_FUNCTION(png_uint_32, png_check_keyword, (png_structrp png_ptr,
+   png_const_charp key, png_bytep new_key), PNG_EMPTY);
+
+#if PNG_ARM_NEON_IMPLEMENTATION == 1
+PNG_INTERNAL_FUNCTION(void,
+                      png_riffle_palette_neon,
+                      (png_structrp),
+                      PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(int,
+                      png_do_expand_palette_rgba8_neon,
+                      (png_structrp,
+                       png_row_infop,
+                       png_const_bytep,
+                       const png_bytepp,
+                       const png_bytepp),
+                      PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(int,
+                      png_do_expand_palette_rgb8_neon,
+                      (png_structrp,
+                       png_row_infop,
+                       png_const_bytep,
+                       const png_bytepp,
+                       const png_bytepp),
+                      PNG_EMPTY);
+#endif
+
+/* Maintainer: Put new private prototypes here ^ */
+
+#include "pngdebug.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PNG_VERSION_INFO_ONLY */
+#endif /* PNGPRIV_H */
Index: /trunk/src/libs/libpng-1.6.45/pngread.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngread.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngread.c	(revision 107811)
@@ -0,0 +1,4228 @@
+
+/* pngread.c - read a PNG file
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file contains routines that an application calls directly to
+ * read a PNG file or stream.
+ */
+
+#include "pngpriv.h"
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
+#  include <errno.h>
+#endif
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Create a PNG structure for reading, and allocate any memory needed. */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
+{
+#ifndef PNG_USER_MEM_SUPPORTED
+   png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+        error_fn, warn_fn, NULL, NULL, NULL);
+#else
+   return png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
+        warn_fn, NULL, NULL, NULL);
+}
+
+/* Alternate create PNG structure for reading, and allocate any memory
+ * needed.
+ */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
+{
+   png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+       error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
+#endif /* USER_MEM */
+
+   if (png_ptr != NULL)
+   {
+      png_ptr->mode = PNG_IS_READ_STRUCT;
+
+      /* Added in libpng-1.6.0; this can be used to detect a read structure if
+       * required (it will be zero in a write structure.)
+       */
+#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+         png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE;
+#     endif
+
+#     ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED
+         png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
+
+         /* In stable builds only warn if an application error can be completely
+          * handled.
+          */
+#        if PNG_RELEASE_BUILD
+            png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
+#        endif
+#     endif
+
+      /* TODO: delay this, it can be done in png_init_io (if the app doesn't
+       * do it itself) avoiding setting the default function if it is not
+       * required.
+       */
+      png_set_read_fn(png_ptr, NULL, NULL);
+   }
+
+   return png_ptr;
+}
+
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the information before the actual image data.  This has been
+ * changed in v0.90 to allow reading a file that already has the magic
+ * bytes read from the stream.  You can tell libpng how many bytes have
+ * been read from the beginning of the stream (up to the maximum of 8)
+ * via png_set_sig_bytes(), and we will only check the remaining bytes
+ * here.  The application can then have access to the signature bytes we
+ * read if it is determined that this isn't a valid PNG file.
+ */
+void PNGAPI
+png_read_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   int keep;
+#endif
+
+   png_debug(1, "in png_read_info");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* Read and check the PNG file signature. */
+   png_read_sig(png_ptr, info_ptr);
+
+   for (;;)
+   {
+      png_uint_32 length = png_read_chunk_header(png_ptr);
+      png_uint_32 chunk_name = png_ptr->chunk_name;
+
+      /* IDAT logic needs to happen here to simplify getting the two flags
+       * right.
+       */
+      if (chunk_name == png_IDAT)
+      {
+         if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+            png_chunk_error(png_ptr, "Missing IHDR before IDAT");
+
+         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+             (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+            png_chunk_error(png_ptr, "Missing PLTE before IDAT");
+
+         else if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+            png_chunk_benign_error(png_ptr, "Too many IDATs found");
+
+         png_ptr->mode |= PNG_HAVE_IDAT;
+      }
+
+      else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      {
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+         png_ptr->mode |= PNG_AFTER_IDAT;
+      }
+
+      /* This should be a binary subdivision search or a hash for
+       * matching the chunk name rather than a linear search.
+       */
+      if (chunk_name == png_IHDR)
+         png_handle_IHDR(png_ptr, info_ptr, length);
+
+      else if (chunk_name == png_IEND)
+         png_handle_IEND(png_ptr, info_ptr, length);
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+      {
+         png_handle_unknown(png_ptr, info_ptr, length, keep);
+
+         if (chunk_name == png_PLTE)
+            png_ptr->mode |= PNG_HAVE_PLTE;
+
+         else if (chunk_name == png_IDAT)
+         {
+            png_ptr->idat_size = 0; /* It has been consumed */
+            break;
+         }
+      }
+#endif
+      else if (chunk_name == png_PLTE)
+         png_handle_PLTE(png_ptr, info_ptr, length);
+
+      else if (chunk_name == png_IDAT)
+      {
+         png_ptr->idat_size = length;
+         break;
+      }
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+      else if (chunk_name == png_bKGD)
+         png_handle_bKGD(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+      else if (chunk_name == png_cHRM)
+         png_handle_cHRM(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_eXIf_SUPPORTED
+      else if (chunk_name == png_eXIf)
+         png_handle_eXIf(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+      else if (chunk_name == png_gAMA)
+         png_handle_gAMA(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+      else if (chunk_name == png_hIST)
+         png_handle_hIST(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+      else if (chunk_name == png_oFFs)
+         png_handle_oFFs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+      else if (chunk_name == png_pCAL)
+         png_handle_pCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+      else if (chunk_name == png_sCAL)
+         png_handle_sCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+      else if (chunk_name == png_pHYs)
+         png_handle_pHYs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+      else if (chunk_name == png_sBIT)
+         png_handle_sBIT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+      else if (chunk_name == png_sRGB)
+         png_handle_sRGB(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+      else if (chunk_name == png_iCCP)
+         png_handle_iCCP(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+      else if (chunk_name == png_sPLT)
+         png_handle_sPLT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+      else if (chunk_name == png_tEXt)
+         png_handle_tEXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+      else if (chunk_name == png_tIME)
+         png_handle_tIME(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+      else if (chunk_name == png_tRNS)
+         png_handle_tRNS(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+      else if (chunk_name == png_zTXt)
+         png_handle_zTXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+      else if (chunk_name == png_iTXt)
+         png_handle_iTXt(png_ptr, info_ptr, length);
+#endif
+
+      else
+         png_handle_unknown(png_ptr, info_ptr, length,
+             PNG_HANDLE_CHUNK_AS_DEFAULT);
+   }
+}
+#endif /* SEQUENTIAL_READ */
+
+/* Optional call to update the users info_ptr structure */
+void PNGAPI
+png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+   png_debug(1, "in png_read_update_info");
+
+   if (png_ptr != NULL)
+   {
+      if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+      {
+         png_read_start_row(png_ptr);
+
+#        ifdef PNG_READ_TRANSFORMS_SUPPORTED
+            png_read_transform_info(png_ptr, info_ptr);
+#        else
+            PNG_UNUSED(info_ptr)
+#        endif
+      }
+
+      /* New in 1.6.0 this avoids the bug of doing the initializations twice */
+      else
+         png_app_error(png_ptr,
+             "png_read_update_info/png_start_read_image: duplicate call");
+   }
+}
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Initialize palette, background, etc, after transformations
+ * are set, but before any reading takes place.  This allows
+ * the user to obtain a gamma-corrected palette, for example.
+ * If the user doesn't call this, we will do it ourselves.
+ */
+void PNGAPI
+png_start_read_image(png_structrp png_ptr)
+{
+   png_debug(1, "in png_start_read_image");
+
+   if (png_ptr != NULL)
+   {
+      if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+         png_read_start_row(png_ptr);
+
+      /* New in 1.6.0 this avoids the bug of doing the initializations twice */
+      else
+         png_app_error(png_ptr,
+             "png_start_read_image/png_read_update_info: duplicate call");
+   }
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Undoes intrapixel differencing,
+ * NOTE: this is apparently only supported in the 'sequential' reader.
+ */
+static void
+png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_read_intrapixel");
+
+   if (
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      int bytes_per_pixel;
+      png_uint_32 row_width = row_info->width;
+
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 3;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 4;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
+            *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
+         }
+      }
+      else if (row_info->bit_depth == 16)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 6;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 8;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            png_uint_32 s0   = (png_uint_32)(*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 red  = (s0 + s1 + 65536) & 0xffff;
+            png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
+            *(rp    ) = (png_byte)((red >> 8) & 0xff);
+            *(rp + 1) = (png_byte)(red & 0xff);
+            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
+            *(rp + 5) = (png_byte)(blue & 0xff);
+         }
+      }
+   }
+}
+#endif /* MNG_FEATURES */
+
+void PNGAPI
+png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
+{
+   png_row_info row_info;
+
+   if (png_ptr == NULL)
+      return;
+
+   png_debug2(1, "in png_read_row (row %lu, pass %d)",
+       (unsigned long)png_ptr->row_number, png_ptr->pass);
+
+   /* png_read_start_row sets the information (in particular iwidth) for this
+    * interlace pass.
+    */
+   if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+      png_read_start_row(png_ptr);
+
+   /* 1.5.6: row_info moved out of png_struct to a local here. */
+   row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
+   row_info.color_type = png_ptr->color_type;
+   row_info.bit_depth = png_ptr->bit_depth;
+   row_info.channels = png_ptr->channels;
+   row_info.pixel_depth = png_ptr->pixel_depth;
+   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+#ifdef PNG_WARNINGS_SUPPORTED
+   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
+   {
+   /* Check for transforms that have been set but were defined out */
+#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+      png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
+      png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
+    !defined(PNG_READ_PACKSWAP_SUPPORTED)
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+      png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
+   if ((png_ptr->transformations & PNG_PACK) != 0)
+      png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
+      png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
+   if ((png_ptr->transformations & PNG_BGR) != 0)
+      png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+      png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
+#endif
+   }
+#endif /* WARNINGS */
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* If interlaced and we do not need a new row, combine row and return.
+    * Notice that the pixels we have from previous rows have been transformed
+    * already; we can only combine like with like (transformed or
+    * untransformed) and, because of the libpng API for interlaced images, this
+    * means we must transform before de-interlacing.
+    */
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      switch (png_ptr->pass)
+      {
+         case 0:
+            if (png_ptr->row_number & 0x07)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 1:
+            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 2:
+            if ((png_ptr->row_number & 0x07) != 4)
+            {
+               if (dsp_row != NULL && (png_ptr->row_number & 4))
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 3:
+            if ((png_ptr->row_number & 3) || png_ptr->width < 3)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 4:
+            if ((png_ptr->row_number & 3) != 2)
+            {
+               if (dsp_row != NULL && (png_ptr->row_number & 2))
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 5:
+            if ((png_ptr->row_number & 1) || png_ptr->width < 2)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         default:
+         case 6:
+            if ((png_ptr->row_number & 1) == 0)
+            {
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+      png_error(png_ptr, "Invalid attempt to read row data");
+
+   /* Fill the row with IDAT data: */
+   png_ptr->row_buf[0]=255; /* to force error if no data was found */
+   png_read_IDAT_data(png_ptr, png_ptr->row_buf, row_info.rowbytes + 1);
+
+   if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
+   {
+      if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
+         png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
+             png_ptr->prev_row + 1, png_ptr->row_buf[0]);
+      else
+         png_error(png_ptr, "bad adaptive filter value");
+   }
+
+   /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
+    * 1.5.6, while the buffer really is this big in current versions of libpng
+    * it may not be in the future, so this was changed just to copy the
+    * interlaced count:
+    */
+   memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
+   {
+      /* Intrapixel differencing */
+      png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
+   }
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+   if (png_ptr->transformations
+#     ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+         || png_ptr->num_palette_max >= 0
+#     endif
+      )
+      png_do_read_transformations(png_ptr, &row_info);
+#endif
+
+   /* The transformed pixel depth should match the depth now in row_info. */
+   if (png_ptr->transformed_pixel_depth == 0)
+   {
+      png_ptr->transformed_pixel_depth = row_info.pixel_depth;
+      if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
+         png_error(png_ptr, "sequential row overflow");
+   }
+
+   else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
+      png_error(png_ptr, "internal sequential row size calculation error");
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   /* Expand interlaced rows to full size */
+   if (png_ptr->interlaced != 0 &&
+      (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      if (png_ptr->pass < 6)
+         png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
+             png_ptr->transformations);
+
+      if (dsp_row != NULL)
+         png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+      if (row != NULL)
+         png_combine_row(png_ptr, row, 0/*row*/);
+   }
+
+   else
+#endif
+   {
+      if (row != NULL)
+         png_combine_row(png_ptr, row, -1/*ignored*/);
+
+      if (dsp_row != NULL)
+         png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
+   }
+   png_read_finish_row(png_ptr);
+
+   if (png_ptr->read_row_fn != NULL)
+      (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
+
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read one or more rows of image data.  If the image is interlaced,
+ * and png_set_interlace_handling() has been called, the rows need to
+ * contain the contents of the rows from the previous pass.  If the
+ * image has alpha or transparency, and png_handle_alpha()[*] has been
+ * called, the rows contents must be initialized to the contents of the
+ * screen.
+ *
+ * "row" holds the actual image, and pixels are placed in it
+ * as they arrive.  If the image is displayed after each pass, it will
+ * appear to "sparkle" in.  "display_row" can be used to display a
+ * "chunky" progressive image, with finer detail added as it becomes
+ * available.  If you do not want this "chunky" display, you may pass
+ * NULL for display_row.  If you do not want the sparkle display, and
+ * you have not called png_handle_alpha(), you may pass NULL for rows.
+ * If you have called png_handle_alpha(), and the image has either an
+ * alpha channel or a transparency chunk, you must provide a buffer for
+ * rows.  In this case, you do not have to provide a display_row buffer
+ * also, but you may.  If the image is not interlaced, or if you have
+ * not called png_set_interlace_handling(), the display_row buffer will
+ * be ignored, so pass NULL to it.
+ *
+ * [*] png_handle_alpha() does not exist yet, as of this version of libpng
+ */
+
+void PNGAPI
+png_read_rows(png_structrp png_ptr, png_bytepp row,
+    png_bytepp display_row, png_uint_32 num_rows)
+{
+   png_uint_32 i;
+   png_bytepp rp;
+   png_bytepp dp;
+
+   png_debug(1, "in png_read_rows");
+
+   if (png_ptr == NULL)
+      return;
+
+   rp = row;
+   dp = display_row;
+   if (rp != NULL && dp != NULL)
+      for (i = 0; i < num_rows; i++)
+      {
+         png_bytep rptr = *rp++;
+         png_bytep dptr = *dp++;
+
+         png_read_row(png_ptr, rptr, dptr);
+      }
+
+   else if (rp != NULL)
+      for (i = 0; i < num_rows; i++)
+      {
+         png_bytep rptr = *rp;
+         png_read_row(png_ptr, rptr, NULL);
+         rp++;
+      }
+
+   else if (dp != NULL)
+      for (i = 0; i < num_rows; i++)
+      {
+         png_bytep dptr = *dp;
+         png_read_row(png_ptr, NULL, dptr);
+         dp++;
+      }
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the entire image.  If the image has an alpha channel or a tRNS
+ * chunk, and you have called png_handle_alpha()[*], you will need to
+ * initialize the image to the current image that PNG will be overlaying.
+ * We set the num_rows again here, in case it was incorrectly set in
+ * png_read_start_row() by a call to png_read_update_info() or
+ * png_start_read_image() if png_set_interlace_handling() wasn't called
+ * prior to either of these functions like it should have been.  You can
+ * only call this function once.  If you desire to have an image for
+ * each pass of a interlaced image, use png_read_rows() instead.
+ *
+ * [*] png_handle_alpha() does not exist yet, as of this version of libpng
+ */
+void PNGAPI
+png_read_image(png_structrp png_ptr, png_bytepp image)
+{
+   png_uint_32 i, image_height;
+   int pass, j;
+   png_bytepp rp;
+
+   png_debug(1, "in png_read_image");
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+   {
+      pass = png_set_interlace_handling(png_ptr);
+      /* And make sure transforms are initialized. */
+      png_start_read_image(png_ptr);
+   }
+   else
+   {
+      if (png_ptr->interlaced != 0 &&
+          (png_ptr->transformations & PNG_INTERLACE) == 0)
+      {
+         /* Caller called png_start_read_image or png_read_update_info without
+          * first turning on the PNG_INTERLACE transform.  We can fix this here,
+          * but the caller should do it!
+          */
+         png_warning(png_ptr, "Interlace handling should be turned on when "
+             "using png_read_image");
+         /* Make sure this is set correctly */
+         png_ptr->num_rows = png_ptr->height;
+      }
+
+      /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
+       * the above error case.
+       */
+      pass = png_set_interlace_handling(png_ptr);
+   }
+#else
+   if (png_ptr->interlaced)
+      png_error(png_ptr,
+          "Cannot read interlaced image -- interlace handler disabled");
+
+   pass = 1;
+#endif
+
+   image_height=png_ptr->height;
+
+   for (j = 0; j < pass; j++)
+   {
+      rp = image;
+      for (i = 0; i < image_height; i++)
+      {
+         png_read_row(png_ptr, *rp, NULL);
+         rp++;
+      }
+   }
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the end of the PNG file.  Will not read past the end of the
+ * file, will verify the end is accurate, and will read any comments
+ * or time information at the end of the file, if info is not NULL.
+ */
+void PNGAPI
+png_read_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   int keep;
+#endif
+
+   png_debug(1, "in png_read_end");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* If png_read_end is called in the middle of reading the rows there may
+    * still be pending IDAT data and an owned zstream.  Deal with this here.
+    */
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   if (png_chunk_unknown_handling(png_ptr, png_IDAT) == 0)
+#endif
+      png_read_finish_IDAT(png_ptr);
+
+#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   /* Report invalid palette index; added at libng-1.5.10 */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+       png_ptr->num_palette_max >= png_ptr->num_palette)
+      png_benign_error(png_ptr, "Read palette index exceeding num_palette");
+#endif
+
+   do
+   {
+      png_uint_32 length = png_read_chunk_header(png_ptr);
+      png_uint_32 chunk_name = png_ptr->chunk_name;
+
+      if (chunk_name != png_IDAT)
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+
+      if (chunk_name == png_IEND)
+         png_handle_IEND(png_ptr, info_ptr, length);
+
+      else if (chunk_name == png_IHDR)
+         png_handle_IHDR(png_ptr, info_ptr, length);
+
+      else if (info_ptr == NULL)
+         png_crc_finish(png_ptr, length);
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+      {
+         if (chunk_name == png_IDAT)
+         {
+            if ((length > 0 && !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
+                || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
+               png_benign_error(png_ptr, ".Too many IDATs found");
+         }
+         png_handle_unknown(png_ptr, info_ptr, length, keep);
+         if (chunk_name == png_PLTE)
+            png_ptr->mode |= PNG_HAVE_PLTE;
+      }
+#endif
+
+      else if (chunk_name == png_IDAT)
+      {
+         /* Zero length IDATs are legal after the last IDAT has been
+          * read, but not after other chunks have been read.  1.6 does not
+          * always read all the deflate data; specifically it cannot be relied
+          * upon to read the Adler32 at the end.  If it doesn't ignore IDAT
+          * chunks which are longer than zero as well:
+          */
+         if ((length > 0 && !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
+             || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
+            png_benign_error(png_ptr, "..Too many IDATs found");
+
+         png_crc_finish(png_ptr, length);
+      }
+      else if (chunk_name == png_PLTE)
+         png_handle_PLTE(png_ptr, info_ptr, length);
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+      else if (chunk_name == png_bKGD)
+         png_handle_bKGD(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+      else if (chunk_name == png_cHRM)
+         png_handle_cHRM(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_eXIf_SUPPORTED
+      else if (chunk_name == png_eXIf)
+         png_handle_eXIf(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+      else if (chunk_name == png_gAMA)
+         png_handle_gAMA(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+      else if (chunk_name == png_hIST)
+         png_handle_hIST(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+      else if (chunk_name == png_oFFs)
+         png_handle_oFFs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+      else if (chunk_name == png_pCAL)
+         png_handle_pCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+      else if (chunk_name == png_sCAL)
+         png_handle_sCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+      else if (chunk_name == png_pHYs)
+         png_handle_pHYs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+      else if (chunk_name == png_sBIT)
+         png_handle_sBIT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+      else if (chunk_name == png_sRGB)
+         png_handle_sRGB(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+      else if (chunk_name == png_iCCP)
+         png_handle_iCCP(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+      else if (chunk_name == png_sPLT)
+         png_handle_sPLT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+      else if (chunk_name == png_tEXt)
+         png_handle_tEXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+      else if (chunk_name == png_tIME)
+         png_handle_tIME(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+      else if (chunk_name == png_tRNS)
+         png_handle_tRNS(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+      else if (chunk_name == png_zTXt)
+         png_handle_zTXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+      else if (chunk_name == png_iTXt)
+         png_handle_iTXt(png_ptr, info_ptr, length);
+#endif
+
+      else
+         png_handle_unknown(png_ptr, info_ptr, length,
+             PNG_HANDLE_CHUNK_AS_DEFAULT);
+   } while ((png_ptr->mode & PNG_HAVE_IEND) == 0);
+}
+#endif /* SEQUENTIAL_READ */
+
+/* Free all memory used in the read struct */
+static void
+png_read_destroy(png_structrp png_ptr)
+{
+   png_debug(1, "in png_read_destroy");
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   png_destroy_gamma_table(png_ptr);
+#endif
+
+   png_free(png_ptr, png_ptr->big_row_buf);
+   png_ptr->big_row_buf = NULL;
+   png_free(png_ptr, png_ptr->big_prev_row);
+   png_ptr->big_prev_row = NULL;
+   png_free(png_ptr, png_ptr->read_buffer);
+   png_ptr->read_buffer = NULL;
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   png_free(png_ptr, png_ptr->palette_lookup);
+   png_ptr->palette_lookup = NULL;
+   png_free(png_ptr, png_ptr->quantize_index);
+   png_ptr->quantize_index = NULL;
+#endif
+
+   if ((png_ptr->free_me & PNG_FREE_PLTE) != 0)
+   {
+      png_zfree(png_ptr, png_ptr->palette);
+      png_ptr->palette = NULL;
+   }
+   png_ptr->free_me &= ~PNG_FREE_PLTE;
+
+#if defined(PNG_tRNS_SUPPORTED) || \
+    defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if ((png_ptr->free_me & PNG_FREE_TRNS) != 0)
+   {
+      png_free(png_ptr, png_ptr->trans_alpha);
+      png_ptr->trans_alpha = NULL;
+   }
+   png_ptr->free_me &= ~PNG_FREE_TRNS;
+#endif
+
+   inflateEnd(&png_ptr->zstream);
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+   png_free(png_ptr, png_ptr->save_buffer);
+   png_ptr->save_buffer = NULL;
+#endif
+
+#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) && \
+   defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+   png_free(png_ptr, png_ptr->unknown_chunk.data);
+   png_ptr->unknown_chunk.data = NULL;
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   png_free(png_ptr, png_ptr->chunk_list);
+   png_ptr->chunk_list = NULL;
+#endif
+
+#if defined(PNG_READ_EXPAND_SUPPORTED) && \
+    defined(PNG_ARM_NEON_IMPLEMENTATION)
+   png_free(png_ptr, png_ptr->riffled_palette);
+   png_ptr->riffled_palette = NULL;
+#endif
+
+   /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error
+    * callbacks are still set at this point.  They are required to complete the
+    * destruction of the png_struct itself.
+    */
+}
+
+/* Free all memory used by the read */
+void PNGAPI
+png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
+    png_infopp end_info_ptr_ptr)
+{
+   png_structrp png_ptr = NULL;
+
+   png_debug(1, "in png_destroy_read_struct");
+
+   if (png_ptr_ptr != NULL)
+      png_ptr = *png_ptr_ptr;
+
+   if (png_ptr == NULL)
+      return;
+
+   /* libpng 1.6.0: use the API to destroy info structs to ensure consistent
+    * behavior.  Prior to 1.6.0 libpng did extra 'info' destruction in this API.
+    * The extra was, apparently, unnecessary yet this hides memory leak bugs.
+    */
+   png_destroy_info_struct(png_ptr, end_info_ptr_ptr);
+   png_destroy_info_struct(png_ptr, info_ptr_ptr);
+
+   *png_ptr_ptr = NULL;
+   png_read_destroy(png_ptr);
+   png_destroy_png_struct(png_ptr);
+}
+
+void PNGAPI
+png_set_read_status_fn(png_structrp png_ptr, png_read_status_ptr read_row_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->read_row_fn = read_row_fn;
+}
+
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+void PNGAPI
+png_read_png(png_structrp png_ptr, png_inforp info_ptr,
+    int transforms, voidp params)
+{
+   png_debug(1, "in png_read_png");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* png_read_info() gives us all of the information from the
+    * PNG file before the first IDAT (image data chunk).
+    */
+   png_read_info(png_ptr, info_ptr);
+   if (info_ptr->height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
+      png_error(png_ptr, "Image is too high to process with png_read_png()");
+
+   /* -------------- image transformations start here ------------------- */
+   /* libpng 1.6.10: add code to cause a png_app_error if a selected TRANSFORM
+    * is not implemented.  This will only happen in de-configured (non-default)
+    * libpng builds.  The results can be unexpected - png_read_png may return
+    * short or mal-formed rows because the transform is skipped.
+    */
+
+   /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
+    */
+   if ((transforms & PNG_TRANSFORM_SCALE_16) != 0)
+      /* Added at libpng-1.5.4. "strip_16" produces the same result that it
+       * did in earlier versions, while "scale_16" is now more accurate.
+       */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+      png_set_scale_16(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SCALE_16 not supported");
+#endif
+
+   /* If both SCALE and STRIP are required pngrtran will effectively cancel the
+    * latter by doing SCALE first.  This is ok and allows apps not to check for
+    * which is supported to get the right answer.
+    */
+   if ((transforms & PNG_TRANSFORM_STRIP_16) != 0)
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+      png_set_strip_16(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_16 not supported");
+#endif
+
+   /* Strip alpha bytes from the input data without combining with
+    * the background (not recommended).
+    */
+   if ((transforms & PNG_TRANSFORM_STRIP_ALPHA) != 0)
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+      png_set_strip_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_ALPHA not supported");
+#endif
+
+   /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
+    * byte into separate bytes (useful for paletted and grayscale images).
+    */
+   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
+#ifdef PNG_READ_PACK_SUPPORTED
+      png_set_packing(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
+#endif
+
+   /* Change the order of packed pixels to least significant bit first
+    * (not useful if you are using png_set_packing).
+    */
+   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+      png_set_packswap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
+#endif
+
+   /* Expand paletted colors into true RGB triplets
+    * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
+    * Expand paletted or RGB images with transparency to full alpha
+    * channels so the data will be available as RGBA quartets.
+    */
+   if ((transforms & PNG_TRANSFORM_EXPAND) != 0)
+#ifdef PNG_READ_EXPAND_SUPPORTED
+      png_set_expand(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND not supported");
+#endif
+
+   /* We don't handle background color or gamma transformation or quantizing.
+    */
+
+   /* Invert monochrome files to have 0 as white and 1 as black
+    */
+   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
+#ifdef PNG_READ_INVERT_SUPPORTED
+      png_set_invert_mono(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
+#endif
+
+   /* If you want to shift the pixel values from the range [0,255] or
+    * [0,65535] to the original [0,7] or [0,31], or whatever range the
+    * colors were originally in:
+    */
+   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
+#ifdef PNG_READ_SHIFT_SUPPORTED
+      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+         png_set_shift(png_ptr, &info_ptr->sig_bit);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
+#endif
+
+   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
+   if ((transforms & PNG_TRANSFORM_BGR) != 0)
+#ifdef PNG_READ_BGR_SUPPORTED
+      png_set_bgr(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
+#endif
+
+   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
+   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+      png_set_swap_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
+#endif
+
+   /* Swap bytes of 16-bit files to least significant byte first */
+   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
+#ifdef PNG_READ_SWAP_SUPPORTED
+      png_set_swap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
+#endif
+
+/* Added at libpng-1.2.41 */
+   /* Invert the alpha channel from opacity to transparency */
+   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+      png_set_invert_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
+#endif
+
+/* Added at libpng-1.2.41 */
+   /* Expand grayscale image to RGB */
+   if ((transforms & PNG_TRANSFORM_GRAY_TO_RGB) != 0)
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+      png_set_gray_to_rgb(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_GRAY_TO_RGB not supported");
+#endif
+
+/* Added at libpng-1.5.4 */
+   if ((transforms & PNG_TRANSFORM_EXPAND_16) != 0)
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+      png_set_expand_16(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND_16 not supported");
+#endif
+
+   /* We don't handle adding filler bytes */
+
+   /* We use png_read_image and rely on that for interlace handling, but we also
+    * call png_read_update_info therefore must turn on interlace handling now:
+    */
+   (void)png_set_interlace_handling(png_ptr);
+
+   /* Optional call to gamma correct and add the background to the palette
+    * and update info structure.  REQUIRED if you are expecting libpng to
+    * update the palette for you (i.e., you selected such a transform above).
+    */
+   png_read_update_info(png_ptr, info_ptr);
+
+   /* -------------- image transformations end here ------------------- */
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
+   if (info_ptr->row_pointers == NULL)
+   {
+      png_uint_32 iptr;
+
+      info_ptr->row_pointers = png_voidcast(png_bytepp, png_malloc(png_ptr,
+          info_ptr->height * (sizeof (png_bytep))));
+
+      for (iptr=0; iptr<info_ptr->height; iptr++)
+         info_ptr->row_pointers[iptr] = NULL;
+
+      info_ptr->free_me |= PNG_FREE_ROWS;
+
+      for (iptr = 0; iptr < info_ptr->height; iptr++)
+         info_ptr->row_pointers[iptr] = png_voidcast(png_bytep,
+             png_malloc(png_ptr, info_ptr->rowbytes));
+   }
+
+   png_read_image(png_ptr, info_ptr->row_pointers);
+   info_ptr->valid |= PNG_INFO_IDAT;
+
+   /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
+   png_read_end(png_ptr, info_ptr);
+
+   PNG_UNUSED(params)
+}
+#endif /* INFO_IMAGE */
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+/* SIMPLIFIED READ
+ *
+ * This code currently relies on the sequential reader, though it could easily
+ * be made to work with the progressive one.
+ */
+/* Arguments to png_image_finish_read: */
+
+/* Encoding of PNG data (used by the color-map code) */
+#  define P_NOTSET  0 /* File encoding not yet known */
+#  define P_sRGB    1 /* 8-bit encoded to sRGB gamma */
+#  define P_LINEAR  2 /* 16-bit linear: not encoded, NOT pre-multiplied! */
+#  define P_FILE    3 /* 8-bit encoded to file gamma, not sRGB or linear */
+#  define P_LINEAR8 4 /* 8-bit linear: only from a file value */
+
+/* Color-map processing: after libpng has run on the PNG image further
+ * processing may be needed to convert the data to color-map indices.
+ */
+#define PNG_CMAP_NONE      0
+#define PNG_CMAP_GA        1 /* Process GA data to a color-map with alpha */
+#define PNG_CMAP_TRANS     2 /* Process GA data to a background index */
+#define PNG_CMAP_RGB       3 /* Process RGB data */
+#define PNG_CMAP_RGB_ALPHA 4 /* Process RGBA data */
+
+/* The following document where the background is for each processing case. */
+#define PNG_CMAP_NONE_BACKGROUND      256
+#define PNG_CMAP_GA_BACKGROUND        231
+#define PNG_CMAP_TRANS_BACKGROUND     254
+#define PNG_CMAP_RGB_BACKGROUND       256
+#define PNG_CMAP_RGB_ALPHA_BACKGROUND 216
+
+typedef struct
+{
+   /* Arguments: */
+   png_imagep image;
+   png_voidp  buffer;
+   png_int_32 row_stride;
+   png_voidp  colormap;
+   png_const_colorp background;
+   /* Local variables: */
+   png_voidp       local_row;
+   png_voidp       first_row;
+   ptrdiff_t       row_bytes;           /* step between rows */
+   int             file_encoding;       /* E_ values above */
+   png_fixed_point gamma_to_linear;     /* For P_FILE, reciprocal of gamma */
+   int             colormap_processing; /* PNG_CMAP_ values above */
+} png_image_read_control;
+
+/* Do all the *safe* initialization - 'safe' means that png_error won't be
+ * called, so setting up the jmp_buf is not required.  This means that anything
+ * called from here must *not* call png_malloc - it has to call png_malloc_warn
+ * instead so that control is returned safely back to this routine.
+ */
+static int
+png_image_read_init(png_imagep image)
+{
+   if (image->opaque == NULL)
+   {
+      png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image,
+          png_safe_error, png_safe_warning);
+
+      /* And set the rest of the structure to NULL to ensure that the various
+       * fields are consistent.
+       */
+      memset(image, 0, (sizeof *image));
+      image->version = PNG_IMAGE_VERSION;
+
+      if (png_ptr != NULL)
+      {
+         png_infop info_ptr = png_create_info_struct(png_ptr);
+
+         if (info_ptr != NULL)
+         {
+            png_controlp control = png_voidcast(png_controlp,
+                png_malloc_warn(png_ptr, (sizeof *control)));
+
+            if (control != NULL)
+            {
+               memset(control, 0, (sizeof *control));
+
+               control->png_ptr = png_ptr;
+               control->info_ptr = info_ptr;
+               control->for_write = 0;
+
+               image->opaque = control;
+               return 1;
+            }
+
+            /* Error clean up */
+            png_destroy_info_struct(png_ptr, &info_ptr);
+         }
+
+         png_destroy_read_struct(&png_ptr, NULL, NULL);
+      }
+
+      return png_image_error(image, "png_image_read: out of memory");
+   }
+
+   return png_image_error(image, "png_image_read: opaque pointer not NULL");
+}
+
+/* Utility to find the base format of a PNG file from a png_struct. */
+static png_uint_32
+png_image_format(png_structrp png_ptr)
+{
+   png_uint_32 format = 0;
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      format |= PNG_FORMAT_FLAG_COLOR;
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      format |= PNG_FORMAT_FLAG_ALPHA;
+
+   /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
+    * sets the png_struct fields; that's all we are interested in here.  The
+    * precise interaction with an app call to png_set_tRNS and PNG file reading
+    * is unclear.
+    */
+   else if (png_ptr->num_trans > 0)
+      format |= PNG_FORMAT_FLAG_ALPHA;
+
+   if (png_ptr->bit_depth == 16)
+      format |= PNG_FORMAT_FLAG_LINEAR;
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) != 0)
+      format |= PNG_FORMAT_FLAG_COLORMAP;
+
+   return format;
+}
+
+/* Is the given gamma significantly different from sRGB?  The test is the same
+ * one used in pngrtran.c when deciding whether to do gamma correction.  The
+ * arithmetic optimizes the division by using the fact that the inverse of the
+ * file sRGB gamma is 2.2
+ */
+static int
+png_gamma_not_sRGB(png_fixed_point g)
+{
+   if (g < PNG_FP_1)
+   {
+      /* An uninitialized gamma is assumed to be sRGB for the simplified API. */
+      if (g == 0)
+         return 0;
+
+      return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */);
+   }
+
+   return 1;
+}
+
+/* Do the main body of a 'png_image_begin_read' function; read the PNG file
+ * header and fill in all the information.  This is executed in a safe context,
+ * unlike the init routine above.
+ */
+static int
+png_image_read_header(png_voidp argument)
+{
+   png_imagep image = png_voidcast(png_imagep, argument);
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_inforp info_ptr = image->opaque->info_ptr;
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+   png_set_benign_errors(png_ptr, 1/*warn*/);
+#endif
+   png_read_info(png_ptr, info_ptr);
+
+   /* Do this the fast way; just read directly out of png_struct. */
+   image->width = png_ptr->width;
+   image->height = png_ptr->height;
+
+   {
+      png_uint_32 format = png_image_format(png_ptr);
+
+      image->format = format;
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+      /* Does the colorspace match sRGB?  If there is no color endpoint
+       * (colorant) information assume yes, otherwise require the
+       * 'ENDPOINTS_MATCHP_sRGB' colorspace flag to have been set.  If the
+       * colorspace has been determined to be invalid ignore it.
+       */
+      if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags
+         & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB|
+            PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS))
+         image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB;
+#endif
+   }
+
+   /* We need the maximum number of entries regardless of the format the
+    * application sets here.
+    */
+   {
+      png_uint_32 cmap_entries;
+
+      switch (png_ptr->color_type)
+      {
+         case PNG_COLOR_TYPE_GRAY:
+            cmap_entries = 1U << png_ptr->bit_depth;
+            break;
+
+         case PNG_COLOR_TYPE_PALETTE:
+            cmap_entries = (png_uint_32)png_ptr->num_palette;
+            break;
+
+         default:
+            cmap_entries = 256;
+            break;
+      }
+
+      if (cmap_entries > 256)
+         cmap_entries = 256;
+
+      image->colormap_entries = cmap_entries;
+   }
+
+   return 1;
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+int PNGAPI
+png_image_begin_read_from_stdio(png_imagep image, FILE* file)
+{
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (file != NULL)
+      {
+         if (png_image_read_init(image) != 0)
+         {
+            /* This is slightly evil, but png_init_io doesn't do anything other
+             * than this and we haven't changed the standard IO functions so
+             * this saves a 'safe' function.
+             */
+            image->opaque->png_ptr->io_ptr = file;
+            return png_safe_execute(image, png_image_read_header, image);
+         }
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_begin_read_from_stdio: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_begin_read_from_stdio: incorrect PNG_IMAGE_VERSION");
+
+   return 0;
+}
+
+int PNGAPI
+png_image_begin_read_from_file(png_imagep image, const char *file_name)
+{
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (file_name != NULL)
+      {
+         FILE *fp = fopen(file_name, "rb");
+
+         if (fp != NULL)
+         {
+            if (png_image_read_init(image) != 0)
+            {
+               image->opaque->png_ptr->io_ptr = fp;
+               image->opaque->owned_file = 1;
+               return png_safe_execute(image, png_image_read_header, image);
+            }
+
+            /* Clean up: just the opened file. */
+            (void)fclose(fp);
+         }
+
+         else
+            return png_image_error(image, strerror(errno));
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_begin_read_from_file: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_begin_read_from_file: incorrect PNG_IMAGE_VERSION");
+
+   return 0;
+}
+#endif /* STDIO */
+
+static void PNGCBAPI
+png_image_memory_read(png_structp png_ptr, png_bytep out, size_t need)
+{
+   if (png_ptr != NULL)
+   {
+      png_imagep image = png_voidcast(png_imagep, png_ptr->io_ptr);
+      if (image != NULL)
+      {
+         png_controlp cp = image->opaque;
+         if (cp != NULL)
+         {
+            png_const_bytep memory = cp->memory;
+            size_t size = cp->size;
+
+            if (memory != NULL && size >= need)
+            {
+               memcpy(out, memory, need);
+               cp->memory = memory + need;
+               cp->size = size - need;
+               return;
+            }
+
+            png_error(png_ptr, "read beyond end of data");
+         }
+      }
+
+      png_error(png_ptr, "invalid memory read");
+   }
+}
+
+int PNGAPI png_image_begin_read_from_memory(png_imagep image,
+    png_const_voidp memory, size_t size)
+{
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (memory != NULL && size > 0)
+      {
+         if (png_image_read_init(image) != 0)
+         {
+            /* Now set the IO functions to read from the memory buffer and
+             * store it into io_ptr.  Again do this in-place to avoid calling a
+             * libpng function that requires error handling.
+             */
+            image->opaque->memory = png_voidcast(png_const_bytep, memory);
+            image->opaque->size = size;
+            image->opaque->png_ptr->io_ptr = image;
+            image->opaque->png_ptr->read_data_fn = png_image_memory_read;
+
+            return png_safe_execute(image, png_image_read_header, image);
+         }
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_begin_read_from_memory: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_begin_read_from_memory: incorrect PNG_IMAGE_VERSION");
+
+   return 0;
+}
+
+/* Utility function to skip chunks that are not used by the simplified image
+ * read functions and an appropriate macro to call it.
+ */
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+static void
+png_image_skip_unused_chunks(png_structrp png_ptr)
+{
+   /* Prepare the reader to ignore all recognized chunks whose data will not
+    * be used, i.e., all chunks recognized by libpng except for those
+    * involved in basic image reading:
+    *
+    *    IHDR, PLTE, IDAT, IEND
+    *
+    * Or image data handling:
+    *
+    *    tRNS, bKGD, gAMA, cHRM, sRGB, [iCCP] and sBIT.
+    *
+    * This provides a small performance improvement and eliminates any
+    * potential vulnerability to security problems in the unused chunks.
+    *
+    * At present the iCCP chunk data isn't used, so iCCP chunk can be ignored
+    * too.  This allows the simplified API to be compiled without iCCP support,
+    * however if the support is there the chunk is still checked to detect
+    * errors (which are unfortunately quite common.)
+    */
+   {
+         static const png_byte chunks_to_process[] = {
+            98,  75,  71,  68, '\0',  /* bKGD */
+            99,  72,  82,  77, '\0',  /* cHRM */
+           103,  65,  77,  65, '\0',  /* gAMA */
+#        ifdef PNG_READ_iCCP_SUPPORTED
+           105,  67,  67,  80, '\0',  /* iCCP */
+#        endif
+           115,  66,  73,  84, '\0',  /* sBIT */
+           115,  82,  71,  66, '\0',  /* sRGB */
+           };
+
+       /* Ignore unknown chunks and all other chunks except for the
+        * IHDR, PLTE, tRNS, IDAT, and IEND chunks.
+        */
+       png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER,
+           NULL, -1);
+
+       /* But do not ignore image data handling chunks */
+       png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT,
+           chunks_to_process, (int)/*SAFE*/(sizeof chunks_to_process)/5);
+   }
+}
+
+#  define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p)
+#else
+#  define PNG_SKIP_CHUNKS(p) ((void)0)
+#endif /* HANDLE_AS_UNKNOWN */
+
+/* The following macro gives the exact rounded answer for all values in the
+ * range 0..255 (it actually divides by 51.2, but the rounding still generates
+ * the correct numbers 0..5
+ */
+#define PNG_DIV51(v8) (((v8) * 5 + 130) >> 8)
+
+/* Utility functions to make particular color-maps */
+static void
+set_file_encoding(png_image_read_control *display)
+{
+   png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
+   if (png_gamma_significant(g) != 0)
+   {
+      if (png_gamma_not_sRGB(g) != 0)
+      {
+         display->file_encoding = P_FILE;
+         display->gamma_to_linear = png_reciprocal(g);
+      }
+
+      else
+         display->file_encoding = P_sRGB;
+   }
+
+   else
+      display->file_encoding = P_LINEAR8;
+}
+
+static unsigned int
+decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding)
+{
+   if (encoding == P_FILE) /* double check */
+      encoding = display->file_encoding;
+
+   if (encoding == P_NOTSET) /* must be the file encoding */
+   {
+      set_file_encoding(display);
+      encoding = display->file_encoding;
+   }
+
+   switch (encoding)
+   {
+      case P_FILE:
+         value = png_gamma_16bit_correct(value*257, display->gamma_to_linear);
+         break;
+
+      case P_sRGB:
+         value = png_sRGB_table[value];
+         break;
+
+      case P_LINEAR:
+         break;
+
+      case P_LINEAR8:
+         value *= 257;
+         break;
+
+#ifdef __GNUC__
+      default:
+         png_error(display->image->opaque->png_ptr,
+             "unexpected encoding (internal error)");
+#endif
+   }
+
+   return value;
+}
+
+static png_uint_32
+png_colormap_compose(png_image_read_control *display,
+    png_uint_32 foreground, int foreground_encoding, png_uint_32 alpha,
+    png_uint_32 background, int encoding)
+{
+   /* The file value is composed on the background, the background has the given
+    * encoding and so does the result, the file is encoded with P_FILE and the
+    * file and alpha are 8-bit values.  The (output) encoding will always be
+    * P_LINEAR or P_sRGB.
+    */
+   png_uint_32 f = decode_gamma(display, foreground, foreground_encoding);
+   png_uint_32 b = decode_gamma(display, background, encoding);
+
+   /* The alpha is always an 8-bit value (it comes from the palette), the value
+    * scaled by 255 is what PNG_sRGB_FROM_LINEAR requires.
+    */
+   f = f * alpha + b * (255-alpha);
+
+   if (encoding == P_LINEAR)
+   {
+      /* Scale to 65535; divide by 255, approximately (in fact this is extremely
+       * accurate, it divides by 255.00000005937181414556, with no overflow.)
+       */
+      f *= 257; /* Now scaled by 65535 */
+      f += f >> 16;
+      f = (f+32768) >> 16;
+   }
+
+   else /* P_sRGB */
+      f = PNG_sRGB_FROM_LINEAR(f);
+
+   return f;
+}
+
+/* NOTE: P_LINEAR values to this routine must be 16-bit, but P_FILE values must
+ * be 8-bit.
+ */
+static void
+png_create_colormap_entry(png_image_read_control *display,
+    png_uint_32 ip, png_uint_32 red, png_uint_32 green, png_uint_32 blue,
+    png_uint_32 alpha, int encoding)
+{
+   png_imagep image = display->image;
+   int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
+       P_LINEAR : P_sRGB;
+   int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
+       (red != green || green != blue);
+
+   if (ip > 255)
+      png_error(image->opaque->png_ptr, "color-map index out of range");
+
+   /* Update the cache with whether the file gamma is significantly different
+    * from sRGB.
+    */
+   if (encoding == P_FILE)
+   {
+      if (display->file_encoding == P_NOTSET)
+         set_file_encoding(display);
+
+      /* Note that the cached value may be P_FILE too, but if it is then the
+       * gamma_to_linear member has been set.
+       */
+      encoding = display->file_encoding;
+   }
+
+   if (encoding == P_FILE)
+   {
+      png_fixed_point g = display->gamma_to_linear;
+
+      red = png_gamma_16bit_correct(red*257, g);
+      green = png_gamma_16bit_correct(green*257, g);
+      blue = png_gamma_16bit_correct(blue*257, g);
+
+      if (convert_to_Y != 0 || output_encoding == P_LINEAR)
+      {
+         alpha *= 257;
+         encoding = P_LINEAR;
+      }
+
+      else
+      {
+         red = PNG_sRGB_FROM_LINEAR(red * 255);
+         green = PNG_sRGB_FROM_LINEAR(green * 255);
+         blue = PNG_sRGB_FROM_LINEAR(blue * 255);
+         encoding = P_sRGB;
+      }
+   }
+
+   else if (encoding == P_LINEAR8)
+   {
+      /* This encoding occurs quite frequently in test cases because PngSuite
+       * includes a gAMA 1.0 chunk with most images.
+       */
+      red *= 257;
+      green *= 257;
+      blue *= 257;
+      alpha *= 257;
+      encoding = P_LINEAR;
+   }
+
+   else if (encoding == P_sRGB &&
+       (convert_to_Y  != 0 || output_encoding == P_LINEAR))
+   {
+      /* The values are 8-bit sRGB values, but must be converted to 16-bit
+       * linear.
+       */
+      red = png_sRGB_table[red];
+      green = png_sRGB_table[green];
+      blue = png_sRGB_table[blue];
+      alpha *= 257;
+      encoding = P_LINEAR;
+   }
+
+   /* This is set if the color isn't gray but the output is. */
+   if (encoding == P_LINEAR)
+   {
+      if (convert_to_Y != 0)
+      {
+         /* NOTE: these values are copied from png_do_rgb_to_gray */
+         png_uint_32 y = (png_uint_32)6968 * red  + (png_uint_32)23434 * green +
+            (png_uint_32)2366 * blue;
+
+         if (output_encoding == P_LINEAR)
+            y = (y + 16384) >> 15;
+
+         else
+         {
+            /* y is scaled by 32768, we need it scaled by 255: */
+            y = (y + 128) >> 8;
+            y *= 255;
+            y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
+            alpha = PNG_DIV257(alpha);
+            encoding = P_sRGB;
+         }
+
+         blue = red = green = y;
+      }
+
+      else if (output_encoding == P_sRGB)
+      {
+         red = PNG_sRGB_FROM_LINEAR(red * 255);
+         green = PNG_sRGB_FROM_LINEAR(green * 255);
+         blue = PNG_sRGB_FROM_LINEAR(blue * 255);
+         alpha = PNG_DIV257(alpha);
+         encoding = P_sRGB;
+      }
+   }
+
+   if (encoding != output_encoding)
+      png_error(image->opaque->png_ptr, "bad encoding (internal error)");
+
+   /* Store the value. */
+   {
+#     ifdef PNG_FORMAT_AFIRST_SUPPORTED
+         int afirst = (image->format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
+            (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
+#     else
+#        define afirst 0
+#     endif
+#     ifdef PNG_FORMAT_BGR_SUPPORTED
+         int bgr = (image->format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
+#     else
+#        define bgr 0
+#     endif
+
+      if (output_encoding == P_LINEAR)
+      {
+         png_uint_16p entry = png_voidcast(png_uint_16p, display->colormap);
+
+         entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
+
+         /* The linear 16-bit values must be pre-multiplied by the alpha channel
+          * value, if less than 65535 (this is, effectively, composite on black
+          * if the alpha channel is removed.)
+          */
+         switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
+         {
+            case 4:
+               entry[afirst ? 0 : 3] = (png_uint_16)alpha;
+               /* FALLTHROUGH */
+
+            case 3:
+               if (alpha < 65535)
+               {
+                  if (alpha > 0)
+                  {
+                     blue = (blue * alpha + 32767U)/65535U;
+                     green = (green * alpha + 32767U)/65535U;
+                     red = (red * alpha + 32767U)/65535U;
+                  }
+
+                  else
+                     red = green = blue = 0;
+               }
+               entry[afirst + (2 ^ bgr)] = (png_uint_16)blue;
+               entry[afirst + 1] = (png_uint_16)green;
+               entry[afirst + bgr] = (png_uint_16)red;
+               break;
+
+            case 2:
+               entry[1 ^ afirst] = (png_uint_16)alpha;
+               /* FALLTHROUGH */
+
+            case 1:
+               if (alpha < 65535)
+               {
+                  if (alpha > 0)
+                     green = (green * alpha + 32767U)/65535U;
+
+                  else
+                     green = 0;
+               }
+               entry[afirst] = (png_uint_16)green;
+               break;
+
+            default:
+               break;
+         }
+      }
+
+      else /* output encoding is P_sRGB */
+      {
+         png_bytep entry = png_voidcast(png_bytep, display->colormap);
+
+         entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
+
+         switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
+         {
+            case 4:
+               entry[afirst ? 0 : 3] = (png_byte)alpha;
+               /* FALLTHROUGH */
+            case 3:
+               entry[afirst + (2 ^ bgr)] = (png_byte)blue;
+               entry[afirst + 1] = (png_byte)green;
+               entry[afirst + bgr] = (png_byte)red;
+               break;
+
+            case 2:
+               entry[1 ^ afirst] = (png_byte)alpha;
+               /* FALLTHROUGH */
+            case 1:
+               entry[afirst] = (png_byte)green;
+               break;
+
+            default:
+               break;
+         }
+      }
+
+#     ifdef afirst
+#        undef afirst
+#     endif
+#     ifdef bgr
+#        undef bgr
+#     endif
+   }
+}
+
+static int
+make_gray_file_colormap(png_image_read_control *display)
+{
+   unsigned int i;
+
+   for (i=0; i<256; ++i)
+      png_create_colormap_entry(display, i, i, i, i, 255, P_FILE);
+
+   return (int)i;
+}
+
+static int
+make_gray_colormap(png_image_read_control *display)
+{
+   unsigned int i;
+
+   for (i=0; i<256; ++i)
+      png_create_colormap_entry(display, i, i, i, i, 255, P_sRGB);
+
+   return (int)i;
+}
+#define PNG_GRAY_COLORMAP_ENTRIES 256
+
+static int
+make_ga_colormap(png_image_read_control *display)
+{
+   unsigned int i, a;
+
+   /* Alpha is retained, the output will be a color-map with entries
+    * selected by six levels of alpha.  One transparent entry, 6 gray
+    * levels for all the intermediate alpha values, leaving 230 entries
+    * for the opaque grays.  The color-map entries are the six values
+    * [0..5]*51, the GA processing uses PNG_DIV51(value) to find the
+    * relevant entry.
+    *
+    * if (alpha > 229) // opaque
+    * {
+    *    // The 231 entries are selected to make the math below work:
+    *    base = 0;
+    *    entry = (231 * gray + 128) >> 8;
+    * }
+    * else if (alpha < 26) // transparent
+    * {
+    *    base = 231;
+    *    entry = 0;
+    * }
+    * else // partially opaque
+    * {
+    *    base = 226 + 6 * PNG_DIV51(alpha);
+    *    entry = PNG_DIV51(gray);
+    * }
+    */
+   i = 0;
+   while (i < 231)
+   {
+      unsigned int gray = (i * 256 + 115) / 231;
+      png_create_colormap_entry(display, i++, gray, gray, gray, 255, P_sRGB);
+   }
+
+   /* 255 is used here for the component values for consistency with the code
+    * that undoes premultiplication in pngwrite.c.
+    */
+   png_create_colormap_entry(display, i++, 255, 255, 255, 0, P_sRGB);
+
+   for (a=1; a<5; ++a)
+   {
+      unsigned int g;
+
+      for (g=0; g<6; ++g)
+         png_create_colormap_entry(display, i++, g*51, g*51, g*51, a*51,
+             P_sRGB);
+   }
+
+   return (int)i;
+}
+
+#define PNG_GA_COLORMAP_ENTRIES 256
+
+static int
+make_rgb_colormap(png_image_read_control *display)
+{
+   unsigned int i, r;
+
+   /* Build a 6x6x6 opaque RGB cube */
+   for (i=r=0; r<6; ++r)
+   {
+      unsigned int g;
+
+      for (g=0; g<6; ++g)
+      {
+         unsigned int b;
+
+         for (b=0; b<6; ++b)
+            png_create_colormap_entry(display, i++, r*51, g*51, b*51, 255,
+                P_sRGB);
+      }
+   }
+
+   return (int)i;
+}
+
+#define PNG_RGB_COLORMAP_ENTRIES 216
+
+/* Return a palette index to the above palette given three 8-bit sRGB values. */
+#define PNG_RGB_INDEX(r,g,b) \
+   ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b)))
+
+static int
+png_image_read_colormap(png_voidp argument)
+{
+   png_image_read_control *display =
+      png_voidcast(png_image_read_control*, argument);
+   png_imagep image = display->image;
+
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_uint_32 output_format = image->format;
+   int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
+      P_LINEAR : P_sRGB;
+
+   unsigned int cmap_entries;
+   unsigned int output_processing;        /* Output processing option */
+   unsigned int data_encoding = P_NOTSET; /* Encoding libpng must produce */
+
+   /* Background information; the background color and the index of this color
+    * in the color-map if it exists (else 256).
+    */
+   unsigned int background_index = 256;
+   png_uint_32 back_r, back_g, back_b;
+
+   /* Flags to accumulate things that need to be done to the input. */
+   int expand_tRNS = 0;
+
+   /* Exclude the NYI feature of compositing onto a color-mapped buffer; it is
+    * very difficult to do, the results look awful, and it is difficult to see
+    * what possible use it is because the application can't control the
+    * color-map.
+    */
+   if (((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0 ||
+         png_ptr->num_trans > 0) /* alpha in input */ &&
+      ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) /* no alpha in output */)
+   {
+      if (output_encoding == P_LINEAR) /* compose on black */
+         back_b = back_g = back_r = 0;
+
+      else if (display->background == NULL /* no way to remove it */)
+         png_error(png_ptr,
+             "background color must be supplied to remove alpha/transparency");
+
+      /* Get a copy of the background color (this avoids repeating the checks
+       * below.)  The encoding is 8-bit sRGB or 16-bit linear, depending on the
+       * output format.
+       */
+      else
+      {
+         back_g = display->background->green;
+         if ((output_format & PNG_FORMAT_FLAG_COLOR) != 0)
+         {
+            back_r = display->background->red;
+            back_b = display->background->blue;
+         }
+         else
+            back_b = back_r = back_g;
+      }
+   }
+
+   else if (output_encoding == P_LINEAR)
+      back_b = back_r = back_g = 65535;
+
+   else
+      back_b = back_r = back_g = 255;
+
+   /* Default the input file gamma if required - this is necessary because
+    * libpng assumes that if no gamma information is present the data is in the
+    * output format, but the simplified API deduces the gamma from the input
+    * format.
+    */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0)
+   {
+      /* Do this directly, not using the png_colorspace functions, to ensure
+       * that it happens even if the colorspace is invalid (though probably if
+       * it is the setting will be ignored)  Note that the same thing can be
+       * achieved at the application interface with png_set_gAMA.
+       */
+      if (png_ptr->bit_depth == 16 &&
+         (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+         png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR;
+
+      else
+         png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE;
+
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+   }
+
+   /* Decide what to do based on the PNG color type of the input data.  The
+    * utility function png_create_colormap_entry deals with most aspects of the
+    * output transformations; this code works out how to produce bytes of
+    * color-map entries from the original format.
+    */
+   switch (png_ptr->color_type)
+   {
+      case PNG_COLOR_TYPE_GRAY:
+         if (png_ptr->bit_depth <= 8)
+         {
+            /* There at most 256 colors in the output, regardless of
+             * transparency.
+             */
+            unsigned int step, i, val, trans = 256/*ignore*/, back_alpha = 0;
+
+            cmap_entries = 1U << png_ptr->bit_depth;
+            if (cmap_entries > image->colormap_entries)
+               png_error(png_ptr, "gray[8] color-map: too few entries");
+
+            step = 255 / (cmap_entries - 1);
+            output_processing = PNG_CMAP_NONE;
+
+            /* If there is a tRNS chunk then this either selects a transparent
+             * value or, if the output has no alpha, the background color.
+             */
+            if (png_ptr->num_trans > 0)
+            {
+               trans = png_ptr->trans_color.gray;
+
+               if ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0)
+                  back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
+            }
+
+            /* png_create_colormap_entry just takes an RGBA and writes the
+             * corresponding color-map entry using the format from 'image',
+             * including the required conversion to sRGB or linear as
+             * appropriate.  The input values are always either sRGB (if the
+             * gamma correction flag is 0) or 0..255 scaled file encoded values
+             * (if the function must gamma correct them).
+             */
+            for (i=val=0; i<cmap_entries; ++i, val += step)
+            {
+               /* 'i' is a file value.  While this will result in duplicated
+                * entries for 8-bit non-sRGB encoded files it is necessary to
+                * have non-gamma corrected values to do tRNS handling.
+                */
+               if (i != trans)
+                  png_create_colormap_entry(display, i, val, val, val, 255,
+                      P_FILE/*8-bit with file gamma*/);
+
+               /* Else this entry is transparent.  The colors don't matter if
+                * there is an alpha channel (back_alpha == 0), but it does no
+                * harm to pass them in; the values are not set above so this
+                * passes in white.
+                *
+                * NOTE: this preserves the full precision of the application
+                * supplied background color when it is used.
+                */
+               else
+                  png_create_colormap_entry(display, i, back_r, back_g, back_b,
+                      back_alpha, output_encoding);
+            }
+
+            /* We need libpng to preserve the original encoding. */
+            data_encoding = P_FILE;
+
+            /* The rows from libpng, while technically gray values, are now also
+             * color-map indices; however, they may need to be expanded to 1
+             * byte per pixel.  This is what png_set_packing does (i.e., it
+             * unpacks the bit values into bytes.)
+             */
+            if (png_ptr->bit_depth < 8)
+               png_set_packing(png_ptr);
+         }
+
+         else /* bit depth is 16 */
+         {
+            /* The 16-bit input values can be converted directly to 8-bit gamma
+             * encoded values; however, if a tRNS chunk is present 257 color-map
+             * entries are required.  This means that the extra entry requires
+             * special processing; add an alpha channel, sacrifice gray level
+             * 254 and convert transparent (alpha==0) entries to that.
+             *
+             * Use libpng to chop the data to 8 bits.  Convert it to sRGB at the
+             * same time to minimize quality loss.  If a tRNS chunk is present
+             * this means libpng must handle it too; otherwise it is impossible
+             * to do the exact match on the 16-bit value.
+             *
+             * If the output has no alpha channel *and* the background color is
+             * gray then it is possible to let libpng handle the substitution by
+             * ensuring that the corresponding gray level matches the background
+             * color exactly.
+             */
+            data_encoding = P_sRGB;
+
+            if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
+               png_error(png_ptr, "gray[16] color-map: too few entries");
+
+            cmap_entries = (unsigned int)make_gray_colormap(display);
+
+            if (png_ptr->num_trans > 0)
+            {
+               unsigned int back_alpha;
+
+               if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+                  back_alpha = 0;
+
+               else
+               {
+                  if (back_r == back_g && back_g == back_b)
+                  {
+                     /* Background is gray; no special processing will be
+                      * required.
+                      */
+                     png_color_16 c;
+                     png_uint_32 gray = back_g;
+
+                     if (output_encoding == P_LINEAR)
+                     {
+                        gray = PNG_sRGB_FROM_LINEAR(gray * 255);
+
+                        /* And make sure the corresponding palette entry
+                         * matches.
+                         */
+                        png_create_colormap_entry(display, gray, back_g, back_g,
+                            back_g, 65535, P_LINEAR);
+                     }
+
+                     /* The background passed to libpng, however, must be the
+                      * sRGB value.
+                      */
+                     c.index = 0; /*unused*/
+                     c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
+
+                     /* NOTE: does this work without expanding tRNS to alpha?
+                      * It should be the color->gray case below apparently
+                      * doesn't.
+                      */
+                     png_set_background_fixed(png_ptr, &c,
+                         PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                         0/*gamma: not used*/);
+
+                     output_processing = PNG_CMAP_NONE;
+                     break;
+                  }
+#ifdef __COVERITY__
+                 /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
+                  * here.
+                  */
+                  back_alpha = 255;
+#else
+                  back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
+#endif
+               }
+
+               /* output_processing means that the libpng-processed row will be
+                * 8-bit GA and it has to be processing to single byte color-map
+                * values.  Entry 254 is replaced by either a completely
+                * transparent entry or by the background color at full
+                * precision (and the background color is not a simple gray
+                * level in this case.)
+                */
+               expand_tRNS = 1;
+               output_processing = PNG_CMAP_TRANS;
+               background_index = 254;
+
+               /* And set (overwrite) color-map entry 254 to the actual
+                * background color at full precision.
+                */
+               png_create_colormap_entry(display, 254, back_r, back_g, back_b,
+                   back_alpha, output_encoding);
+            }
+
+            else
+               output_processing = PNG_CMAP_NONE;
+         }
+         break;
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         /* 8-bit or 16-bit PNG with two channels - gray and alpha.  A minimum
+          * of 65536 combinations.  If, however, the alpha channel is to be
+          * removed there are only 256 possibilities if the background is gray.
+          * (Otherwise there is a subset of the 65536 possibilities defined by
+          * the triangle between black, white and the background color.)
+          *
+          * Reduce 16-bit files to 8-bit and sRGB encode the result.  No need to
+          * worry about tRNS matching - tRNS is ignored if there is an alpha
+          * channel.
+          */
+         data_encoding = P_sRGB;
+
+         if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         {
+            if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
+               png_error(png_ptr, "gray+alpha color-map: too few entries");
+
+            cmap_entries = (unsigned int)make_ga_colormap(display);
+
+            background_index = PNG_CMAP_GA_BACKGROUND;
+            output_processing = PNG_CMAP_GA;
+         }
+
+         else /* alpha is removed */
+         {
+            /* Alpha must be removed as the PNG data is processed when the
+             * background is a color because the G and A channels are
+             * independent and the vector addition (non-parallel vectors) is a
+             * 2-D problem.
+             *
+             * This can be reduced to the same algorithm as above by making a
+             * colormap containing gray levels (for the opaque grays), a
+             * background entry (for a transparent pixel) and a set of four six
+             * level color values, one set for each intermediate alpha value.
+             * See the comments in make_ga_colormap for how this works in the
+             * per-pixel processing.
+             *
+             * If the background is gray, however, we only need a 256 entry gray
+             * level color map.  It is sufficient to make the entry generated
+             * for the background color be exactly the color specified.
+             */
+            if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0 ||
+               (back_r == back_g && back_g == back_b))
+            {
+               /* Background is gray; no special processing will be required. */
+               png_color_16 c;
+               png_uint_32 gray = back_g;
+
+               if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "gray-alpha color-map: too few entries");
+
+               cmap_entries = (unsigned int)make_gray_colormap(display);
+
+               if (output_encoding == P_LINEAR)
+               {
+                  gray = PNG_sRGB_FROM_LINEAR(gray * 255);
+
+                  /* And make sure the corresponding palette entry matches. */
+                  png_create_colormap_entry(display, gray, back_g, back_g,
+                      back_g, 65535, P_LINEAR);
+               }
+
+               /* The background passed to libpng, however, must be the sRGB
+                * value.
+                */
+               c.index = 0; /*unused*/
+               c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
+
+               png_set_background_fixed(png_ptr, &c,
+                   PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                   0/*gamma: not used*/);
+
+               output_processing = PNG_CMAP_NONE;
+            }
+
+            else
+            {
+               png_uint_32 i, a;
+
+               /* This is the same as png_make_ga_colormap, above, except that
+                * the entries are all opaque.
+                */
+               if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "ga-alpha color-map: too few entries");
+
+               i = 0;
+               while (i < 231)
+               {
+                  png_uint_32 gray = (i * 256 + 115) / 231;
+                  png_create_colormap_entry(display, i++, gray, gray, gray,
+                      255, P_sRGB);
+               }
+
+               /* NOTE: this preserves the full precision of the application
+                * background color.
+                */
+               background_index = i;
+               png_create_colormap_entry(display, i++, back_r, back_g, back_b,
+#ifdef __COVERITY__
+                   /* Coverity claims that output_encoding
+                    * cannot be 2 (P_LINEAR) here.
+                    */ 255U,
+#else
+                    output_encoding == P_LINEAR ? 65535U : 255U,
+#endif
+                    output_encoding);
+
+               /* For non-opaque input composite on the sRGB background - this
+                * requires inverting the encoding for each component.  The input
+                * is still converted to the sRGB encoding because this is a
+                * reasonable approximate to the logarithmic curve of human
+                * visual sensitivity, at least over the narrow range which PNG
+                * represents.  Consequently 'G' is always sRGB encoded, while
+                * 'A' is linear.  We need the linear background colors.
+                */
+               if (output_encoding == P_sRGB) /* else already linear */
+               {
+                  /* This may produce a value not exactly matching the
+                   * background, but that's ok because these numbers are only
+                   * used when alpha != 0
+                   */
+                  back_r = png_sRGB_table[back_r];
+                  back_g = png_sRGB_table[back_g];
+                  back_b = png_sRGB_table[back_b];
+               }
+
+               for (a=1; a<5; ++a)
+               {
+                  unsigned int g;
+
+                  /* PNG_sRGB_FROM_LINEAR expects a 16-bit linear value scaled
+                   * by an 8-bit alpha value (0..255).
+                   */
+                  png_uint_32 alpha = 51 * a;
+                  png_uint_32 back_rx = (255-alpha) * back_r;
+                  png_uint_32 back_gx = (255-alpha) * back_g;
+                  png_uint_32 back_bx = (255-alpha) * back_b;
+
+                  for (g=0; g<6; ++g)
+                  {
+                     png_uint_32 gray = png_sRGB_table[g*51] * alpha;
+
+                     png_create_colormap_entry(display, i++,
+                         PNG_sRGB_FROM_LINEAR(gray + back_rx),
+                         PNG_sRGB_FROM_LINEAR(gray + back_gx),
+                         PNG_sRGB_FROM_LINEAR(gray + back_bx), 255, P_sRGB);
+                  }
+               }
+
+               cmap_entries = i;
+               output_processing = PNG_CMAP_GA;
+            }
+         }
+         break;
+
+      case PNG_COLOR_TYPE_RGB:
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         /* Exclude the case where the output is gray; we can always handle this
+          * with the cases above.
+          */
+         if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0)
+         {
+            /* The color-map will be grayscale, so we may as well convert the
+             * input RGB values to a simple grayscale and use the grayscale
+             * code above.
+             *
+             * NOTE: calling this apparently damages the recognition of the
+             * transparent color in background color handling; call
+             * png_set_tRNS_to_alpha before png_set_background_fixed.
+             */
+            png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, -1,
+                -1);
+            data_encoding = P_sRGB;
+
+            /* The output will now be one or two 8-bit gray or gray+alpha
+             * channels.  The more complex case arises when the input has alpha.
+             */
+            if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+               png_ptr->num_trans > 0) &&
+               (output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            {
+               /* Both input and output have an alpha channel, so no background
+                * processing is required; just map the GA bytes to the right
+                * color-map entry.
+                */
+               expand_tRNS = 1;
+
+               if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "rgb[ga] color-map: too few entries");
+
+               cmap_entries = (unsigned int)make_ga_colormap(display);
+               background_index = PNG_CMAP_GA_BACKGROUND;
+               output_processing = PNG_CMAP_GA;
+            }
+
+            else
+            {
+               /* Either the input or the output has no alpha channel, so there
+                * will be no non-opaque pixels in the color-map; it will just be
+                * grayscale.
+                */
+               if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "rgb[gray] color-map: too few entries");
+
+               /* Ideally this code would use libpng to do the gamma correction,
+                * but if an input alpha channel is to be removed we will hit the
+                * libpng bug in gamma+compose+rgb-to-gray (the double gamma
+                * correction bug).  Fix this by dropping the gamma correction in
+                * this case and doing it in the palette; this will result in
+                * duplicate palette entries, but that's better than the
+                * alternative of double gamma correction.
+                */
+               if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+                  png_ptr->num_trans > 0) &&
+                  png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
+               {
+                  cmap_entries = (unsigned int)make_gray_file_colormap(display);
+                  data_encoding = P_FILE;
+               }
+
+               else
+                  cmap_entries = (unsigned int)make_gray_colormap(display);
+
+               /* But if the input has alpha or transparency it must be removed
+                */
+               if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+                  png_ptr->num_trans > 0)
+               {
+                  png_color_16 c;
+                  png_uint_32 gray = back_g;
+
+                  /* We need to ensure that the application background exists in
+                   * the colormap and that completely transparent pixels map to
+                   * it.  Achieve this simply by ensuring that the entry
+                   * selected for the background really is the background color.
+                   */
+                  if (data_encoding == P_FILE) /* from the fixup above */
+                  {
+                     /* The app supplied a gray which is in output_encoding, we
+                      * need to convert it to a value of the input (P_FILE)
+                      * encoding then set this palette entry to the required
+                      * output encoding.
+                      */
+                     if (output_encoding == P_sRGB)
+                        gray = png_sRGB_table[gray]; /* now P_LINEAR */
+
+                     gray = PNG_DIV257(png_gamma_16bit_correct(gray,
+                         png_ptr->colorspace.gamma)); /* now P_FILE */
+
+                     /* And make sure the corresponding palette entry contains
+                      * exactly the required sRGB value.
+                      */
+                     png_create_colormap_entry(display, gray, back_g, back_g,
+                         back_g, 0/*unused*/, output_encoding);
+                  }
+
+                  else if (output_encoding == P_LINEAR)
+                  {
+                     gray = PNG_sRGB_FROM_LINEAR(gray * 255);
+
+                     /* And make sure the corresponding palette entry matches.
+                      */
+                     png_create_colormap_entry(display, gray, back_g, back_g,
+                        back_g, 0/*unused*/, P_LINEAR);
+                  }
+
+                  /* The background passed to libpng, however, must be the
+                   * output (normally sRGB) value.
+                   */
+                  c.index = 0; /*unused*/
+                  c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
+
+                  /* NOTE: the following is apparently a bug in libpng. Without
+                   * it the transparent color recognition in
+                   * png_set_background_fixed seems to go wrong.
+                   */
+                  expand_tRNS = 1;
+                  png_set_background_fixed(png_ptr, &c,
+                      PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                      0/*gamma: not used*/);
+               }
+
+               output_processing = PNG_CMAP_NONE;
+            }
+         }
+
+         else /* output is color */
+         {
+            /* We could use png_quantize here so long as there is no transparent
+             * color or alpha; png_quantize ignores alpha.  Easier overall just
+             * to do it once and using PNG_DIV51 on the 6x6x6 reduced RGB cube.
+             * Consequently we always want libpng to produce sRGB data.
+             */
+            data_encoding = P_sRGB;
+
+            /* Is there any transparency or alpha? */
+            if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+               png_ptr->num_trans > 0)
+            {
+               /* Is there alpha in the output too?  If so all four channels are
+                * processed into a special RGB cube with alpha support.
+                */
+               if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+               {
+                  png_uint_32 r;
+
+                  if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
+                     png_error(png_ptr, "rgb+alpha color-map: too few entries");
+
+                  cmap_entries = (unsigned int)make_rgb_colormap(display);
+
+                  /* Add a transparent entry. */
+                  png_create_colormap_entry(display, cmap_entries, 255, 255,
+                      255, 0, P_sRGB);
+
+                  /* This is stored as the background index for the processing
+                   * algorithm.
+                   */
+                  background_index = cmap_entries++;
+
+                  /* Add 27 r,g,b entries each with alpha 0.5. */
+                  for (r=0; r<256; r = (r << 1) | 0x7f)
+                  {
+                     png_uint_32 g;
+
+                     for (g=0; g<256; g = (g << 1) | 0x7f)
+                     {
+                        png_uint_32 b;
+
+                        /* This generates components with the values 0, 127 and
+                         * 255
+                         */
+                        for (b=0; b<256; b = (b << 1) | 0x7f)
+                           png_create_colormap_entry(display, cmap_entries++,
+                               r, g, b, 128, P_sRGB);
+                     }
+                  }
+
+                  expand_tRNS = 1;
+                  output_processing = PNG_CMAP_RGB_ALPHA;
+               }
+
+               else
+               {
+                  /* Alpha/transparency must be removed.  The background must
+                   * exist in the color map (achieved by setting adding it after
+                   * the 666 color-map).  If the standard processing code will
+                   * pick up this entry automatically that's all that is
+                   * required; libpng can be called to do the background
+                   * processing.
+                   */
+                  unsigned int sample_size =
+                     PNG_IMAGE_SAMPLE_SIZE(output_format);
+                  png_uint_32 r, g, b; /* sRGB background */
+
+                  if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
+                     png_error(png_ptr, "rgb-alpha color-map: too few entries");
+
+                  cmap_entries = (unsigned int)make_rgb_colormap(display);
+
+                  png_create_colormap_entry(display, cmap_entries, back_r,
+                      back_g, back_b, 0/*unused*/, output_encoding);
+
+                  if (output_encoding == P_LINEAR)
+                  {
+                     r = PNG_sRGB_FROM_LINEAR(back_r * 255);
+                     g = PNG_sRGB_FROM_LINEAR(back_g * 255);
+                     b = PNG_sRGB_FROM_LINEAR(back_b * 255);
+                  }
+
+                  else
+                  {
+                     r = back_r;
+                     g = back_g;
+                     b = back_g;
+                  }
+
+                  /* Compare the newly-created color-map entry with the one the
+                   * PNG_CMAP_RGB algorithm will use.  If the two entries don't
+                   * match, add the new one and set this as the background
+                   * index.
+                   */
+                  if (memcmp((png_const_bytep)display->colormap +
+                      sample_size * cmap_entries,
+                      (png_const_bytep)display->colormap +
+                          sample_size * PNG_RGB_INDEX(r,g,b),
+                     sample_size) != 0)
+                  {
+                     /* The background color must be added. */
+                     background_index = cmap_entries++;
+
+                     /* Add 27 r,g,b entries each with created by composing with
+                      * the background at alpha 0.5.
+                      */
+                     for (r=0; r<256; r = (r << 1) | 0x7f)
+                     {
+                        for (g=0; g<256; g = (g << 1) | 0x7f)
+                        {
+                           /* This generates components with the values 0, 127
+                            * and 255
+                            */
+                           for (b=0; b<256; b = (b << 1) | 0x7f)
+                              png_create_colormap_entry(display, cmap_entries++,
+                                  png_colormap_compose(display, r, P_sRGB, 128,
+                                      back_r, output_encoding),
+                                  png_colormap_compose(display, g, P_sRGB, 128,
+                                      back_g, output_encoding),
+                                  png_colormap_compose(display, b, P_sRGB, 128,
+                                      back_b, output_encoding),
+                                  0/*unused*/, output_encoding);
+                        }
+                     }
+
+                     expand_tRNS = 1;
+                     output_processing = PNG_CMAP_RGB_ALPHA;
+                  }
+
+                  else /* background color is in the standard color-map */
+                  {
+                     png_color_16 c;
+
+                     c.index = 0; /*unused*/
+                     c.red = (png_uint_16)back_r;
+                     c.gray = c.green = (png_uint_16)back_g;
+                     c.blue = (png_uint_16)back_b;
+
+                     png_set_background_fixed(png_ptr, &c,
+                         PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                         0/*gamma: not used*/);
+
+                     output_processing = PNG_CMAP_RGB;
+                  }
+               }
+            }
+
+            else /* no alpha or transparency in the input */
+            {
+               /* Alpha in the output is irrelevant, simply map the opaque input
+                * pixels to the 6x6x6 color-map.
+                */
+               if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries)
+                  png_error(png_ptr, "rgb color-map: too few entries");
+
+               cmap_entries = (unsigned int)make_rgb_colormap(display);
+               output_processing = PNG_CMAP_RGB;
+            }
+         }
+         break;
+
+      case PNG_COLOR_TYPE_PALETTE:
+         /* It's already got a color-map.  It may be necessary to eliminate the
+          * tRNS entries though.
+          */
+         {
+            unsigned int num_trans = png_ptr->num_trans;
+            png_const_bytep trans = num_trans > 0 ? png_ptr->trans_alpha : NULL;
+            png_const_colorp colormap = png_ptr->palette;
+            int do_background = trans != NULL &&
+               (output_format & PNG_FORMAT_FLAG_ALPHA) == 0;
+            unsigned int i;
+
+            /* Just in case: */
+            if (trans == NULL)
+               num_trans = 0;
+
+            output_processing = PNG_CMAP_NONE;
+            data_encoding = P_FILE; /* Don't change from color-map indices */
+            cmap_entries = (unsigned int)png_ptr->num_palette;
+            if (cmap_entries > 256)
+               cmap_entries = 256;
+
+            if (cmap_entries > (unsigned int)image->colormap_entries)
+               png_error(png_ptr, "palette color-map: too few entries");
+
+            for (i=0; i < cmap_entries; ++i)
+            {
+               if (do_background != 0 && i < num_trans && trans[i] < 255)
+               {
+                  if (trans[i] == 0)
+                     png_create_colormap_entry(display, i, back_r, back_g,
+                         back_b, 0, output_encoding);
+
+                  else
+                  {
+                     /* Must compose the PNG file color in the color-map entry
+                      * on the sRGB color in 'back'.
+                      */
+                     png_create_colormap_entry(display, i,
+                         png_colormap_compose(display, colormap[i].red,
+                             P_FILE, trans[i], back_r, output_encoding),
+                         png_colormap_compose(display, colormap[i].green,
+                             P_FILE, trans[i], back_g, output_encoding),
+                         png_colormap_compose(display, colormap[i].blue,
+                             P_FILE, trans[i], back_b, output_encoding),
+                         output_encoding == P_LINEAR ? trans[i] * 257U :
+                             trans[i],
+                         output_encoding);
+                  }
+               }
+
+               else
+                  png_create_colormap_entry(display, i, colormap[i].red,
+                      colormap[i].green, colormap[i].blue,
+                      i < num_trans ? trans[i] : 255U, P_FILE/*8-bit*/);
+            }
+
+            /* The PNG data may have indices packed in fewer than 8 bits, it
+             * must be expanded if so.
+             */
+            if (png_ptr->bit_depth < 8)
+               png_set_packing(png_ptr);
+         }
+         break;
+
+      default:
+         png_error(png_ptr, "invalid PNG color type");
+         /*NOT REACHED*/
+   }
+
+   /* Now deal with the output processing */
+   if (expand_tRNS != 0 && png_ptr->num_trans > 0 &&
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
+      png_set_tRNS_to_alpha(png_ptr);
+
+   switch (data_encoding)
+   {
+      case P_sRGB:
+         /* Change to 8-bit sRGB */
+         png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB);
+         /* FALLTHROUGH */
+
+      case P_FILE:
+         if (png_ptr->bit_depth > 8)
+            png_set_scale_16(png_ptr);
+         break;
+
+#ifdef __GNUC__
+      default:
+         png_error(png_ptr, "bad data option (internal error)");
+#endif
+   }
+
+   if (cmap_entries > 256 || cmap_entries > image->colormap_entries)
+      png_error(png_ptr, "color map overflow (BAD internal error)");
+
+   image->colormap_entries = cmap_entries;
+
+   /* Double check using the recorded background index */
+   switch (output_processing)
+   {
+      case PNG_CMAP_NONE:
+         if (background_index != PNG_CMAP_NONE_BACKGROUND)
+            goto bad_background;
+         break;
+
+      case PNG_CMAP_GA:
+         if (background_index != PNG_CMAP_GA_BACKGROUND)
+            goto bad_background;
+         break;
+
+      case PNG_CMAP_TRANS:
+         if (background_index >= cmap_entries ||
+            background_index != PNG_CMAP_TRANS_BACKGROUND)
+            goto bad_background;
+         break;
+
+      case PNG_CMAP_RGB:
+         if (background_index != PNG_CMAP_RGB_BACKGROUND)
+            goto bad_background;
+         break;
+
+      case PNG_CMAP_RGB_ALPHA:
+         if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND)
+            goto bad_background;
+         break;
+
+      default:
+         png_error(png_ptr, "bad processing option (internal error)");
+
+      bad_background:
+         png_error(png_ptr, "bad background index (internal error)");
+   }
+
+   display->colormap_processing = (int)output_processing;
+
+   return 1/*ok*/;
+}
+
+/* The final part of the color-map read called from png_image_finish_read. */
+static int
+png_image_read_and_map(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   int passes;
+
+   /* Called when the libpng data must be transformed into the color-mapped
+    * form.  There is a local row buffer in display->local and this routine must
+    * do the interlace handling.
+    */
+   switch (png_ptr->interlaced)
+   {
+      case PNG_INTERLACE_NONE:
+         passes = 1;
+         break;
+
+      case PNG_INTERLACE_ADAM7:
+         passes = PNG_INTERLACE_ADAM7_PASSES;
+         break;
+
+      default:
+         png_error(png_ptr, "unknown interlace type");
+   }
+
+   {
+      png_uint_32  height = image->height;
+      png_uint_32  width = image->width;
+      int          proc = display->colormap_processing;
+      png_bytep    first_row = png_voidcast(png_bytep, display->first_row);
+      ptrdiff_t    step_row = display->row_bytes;
+      int pass;
+
+      for (pass = 0; pass < passes; ++pass)
+      {
+         unsigned int     startx, stepx, stepy;
+         png_uint_32      y;
+
+         if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+         {
+            /* The row may be empty for a short image: */
+            if (PNG_PASS_COLS(width, pass) == 0)
+               continue;
+
+            startx = PNG_PASS_START_COL(pass);
+            stepx = PNG_PASS_COL_OFFSET(pass);
+            y = PNG_PASS_START_ROW(pass);
+            stepy = PNG_PASS_ROW_OFFSET(pass);
+         }
+
+         else
+         {
+            y = 0;
+            startx = 0;
+            stepx = stepy = 1;
+         }
+
+         for (; y<height; y += stepy)
+         {
+            png_bytep inrow = png_voidcast(png_bytep, display->local_row);
+            png_bytep outrow = first_row + y * step_row;
+            png_const_bytep end_row = outrow + width;
+
+            /* Read read the libpng data into the temporary buffer. */
+            png_read_row(png_ptr, inrow, NULL);
+
+            /* Now process the row according to the processing option, note
+             * that the caller verifies that the format of the libpng output
+             * data is as required.
+             */
+            outrow += startx;
+            switch (proc)
+            {
+               case PNG_CMAP_GA:
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     /* The data is always in the PNG order */
+                     unsigned int gray = *inrow++;
+                     unsigned int alpha = *inrow++;
+                     unsigned int entry;
+
+                     /* NOTE: this code is copied as a comment in
+                      * make_ga_colormap above.  Please update the
+                      * comment if you change this code!
+                      */
+                     if (alpha > 229) /* opaque */
+                     {
+                        entry = (231 * gray + 128) >> 8;
+                     }
+                     else if (alpha < 26) /* transparent */
+                     {
+                        entry = 231;
+                     }
+                     else /* partially opaque */
+                     {
+                        entry = 226 + 6 * PNG_DIV51(alpha) + PNG_DIV51(gray);
+                     }
+
+                     *outrow = (png_byte)entry;
+                  }
+                  break;
+
+               case PNG_CMAP_TRANS:
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     png_byte gray = *inrow++;
+                     png_byte alpha = *inrow++;
+
+                     if (alpha == 0)
+                        *outrow = PNG_CMAP_TRANS_BACKGROUND;
+
+                     else if (gray != PNG_CMAP_TRANS_BACKGROUND)
+                        *outrow = gray;
+
+                     else
+                        *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1);
+                  }
+                  break;
+
+               case PNG_CMAP_RGB:
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], inrow[2]);
+                     inrow += 3;
+                  }
+                  break;
+
+               case PNG_CMAP_RGB_ALPHA:
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     unsigned int alpha = inrow[3];
+
+                     /* Because the alpha entries only hold alpha==0.5 values
+                      * split the processing at alpha==0.25 (64) and 0.75
+                      * (196).
+                      */
+
+                     if (alpha >= 196)
+                        *outrow = PNG_RGB_INDEX(inrow[0], inrow[1],
+                            inrow[2]);
+
+                     else if (alpha < 64)
+                        *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND;
+
+                     else
+                     {
+                        /* Likewise there are three entries for each of r, g
+                         * and b.  We could select the entry by popcount on
+                         * the top two bits on those architectures that
+                         * support it, this is what the code below does,
+                         * crudely.
+                         */
+                        unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1;
+
+                        /* Here are how the values map:
+                         *
+                         * 0x00 .. 0x3f -> 0
+                         * 0x40 .. 0xbf -> 1
+                         * 0xc0 .. 0xff -> 2
+                         *
+                         * So, as above with the explicit alpha checks, the
+                         * breakpoints are at 64 and 196.
+                         */
+                        if (inrow[0] & 0x80) back_i += 9; /* red */
+                        if (inrow[0] & 0x40) back_i += 9;
+                        if (inrow[0] & 0x80) back_i += 3; /* green */
+                        if (inrow[0] & 0x40) back_i += 3;
+                        if (inrow[0] & 0x80) back_i += 1; /* blue */
+                        if (inrow[0] & 0x40) back_i += 1;
+
+                        *outrow = (png_byte)back_i;
+                     }
+
+                     inrow += 4;
+                  }
+                  break;
+
+               default:
+                  break;
+            }
+         }
+      }
+   }
+
+   return 1;
+}
+
+static int
+png_image_read_colormapped(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_controlp control = image->opaque;
+   png_structrp png_ptr = control->png_ptr;
+   png_inforp info_ptr = control->info_ptr;
+
+   int passes = 0; /* As a flag */
+
+   PNG_SKIP_CHUNKS(png_ptr);
+
+   /* Update the 'info' structure and make sure the result is as required; first
+    * make sure to turn on the interlace handling if it will be required
+    * (because it can't be turned on *after* the call to png_read_update_info!)
+    */
+   if (display->colormap_processing == PNG_CMAP_NONE)
+      passes = png_set_interlace_handling(png_ptr);
+
+   png_read_update_info(png_ptr, info_ptr);
+
+   /* The expected output can be deduced from the colormap_processing option. */
+   switch (display->colormap_processing)
+   {
+      case PNG_CMAP_NONE:
+         /* Output must be one channel and one byte per pixel, the output
+          * encoding can be anything.
+          */
+         if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
+            info_ptr->color_type == PNG_COLOR_TYPE_GRAY) &&
+            info_ptr->bit_depth == 8)
+            break;
+
+         goto bad_output;
+
+      case PNG_CMAP_TRANS:
+      case PNG_CMAP_GA:
+         /* Output must be two channels and the 'G' one must be sRGB, the latter
+          * can be checked with an exact number because it should have been set
+          * to this number above!
+          */
+         if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+            info_ptr->bit_depth == 8 &&
+            png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
+            image->colormap_entries == 256)
+            break;
+
+         goto bad_output;
+
+      case PNG_CMAP_RGB:
+         /* Output must be 8-bit sRGB encoded RGB */
+         if (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+            info_ptr->bit_depth == 8 &&
+            png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
+            image->colormap_entries == 216)
+            break;
+
+         goto bad_output;
+
+      case PNG_CMAP_RGB_ALPHA:
+         /* Output must be 8-bit sRGB encoded RGBA */
+         if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+            info_ptr->bit_depth == 8 &&
+            png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
+            image->colormap_entries == 244 /* 216 + 1 + 27 */)
+            break;
+
+         goto bad_output;
+
+      default:
+      bad_output:
+         png_error(png_ptr, "bad color-map processing (internal error)");
+   }
+
+   /* Now read the rows.  Do this here if it is possible to read directly into
+    * the output buffer, otherwise allocate a local row buffer of the maximum
+    * size libpng requires and call the relevant processing routine safely.
+    */
+   {
+      png_voidp first_row = display->buffer;
+      ptrdiff_t row_bytes = display->row_stride;
+
+      /* The following expression is designed to work correctly whether it gives
+       * a signed or an unsigned result.
+       */
+      if (row_bytes < 0)
+      {
+         char *ptr = png_voidcast(char*, first_row);
+         ptr += (image->height-1) * (-row_bytes);
+         first_row = png_voidcast(png_voidp, ptr);
+      }
+
+      display->first_row = first_row;
+      display->row_bytes = row_bytes;
+   }
+
+   if (passes == 0)
+   {
+      int result;
+      png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
+
+      display->local_row = row;
+      result = png_safe_execute(image, png_image_read_and_map, display);
+      display->local_row = NULL;
+      png_free(png_ptr, row);
+
+      return result;
+   }
+
+   else
+   {
+      png_alloc_size_t row_bytes = (png_alloc_size_t)display->row_bytes;
+
+      while (--passes >= 0)
+      {
+         png_uint_32      y = image->height;
+         png_bytep        row = png_voidcast(png_bytep, display->first_row);
+
+         for (; y > 0; --y)
+         {
+            png_read_row(png_ptr, row, NULL);
+            row += row_bytes;
+         }
+      }
+
+      return 1;
+   }
+}
+
+/* Just the row reading part of png_image_read. */
+static int
+png_image_read_composite(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   int passes;
+
+   switch (png_ptr->interlaced)
+   {
+      case PNG_INTERLACE_NONE:
+         passes = 1;
+         break;
+
+      case PNG_INTERLACE_ADAM7:
+         passes = PNG_INTERLACE_ADAM7_PASSES;
+         break;
+
+      default:
+         png_error(png_ptr, "unknown interlace type");
+   }
+
+   {
+      png_uint_32  height = image->height;
+      png_uint_32  width = image->width;
+      ptrdiff_t    step_row = display->row_bytes;
+      unsigned int channels =
+          (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
+      int pass;
+
+      for (pass = 0; pass < passes; ++pass)
+      {
+         unsigned int     startx, stepx, stepy;
+         png_uint_32      y;
+
+         if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+         {
+            /* The row may be empty for a short image: */
+            if (PNG_PASS_COLS(width, pass) == 0)
+               continue;
+
+            startx = PNG_PASS_START_COL(pass) * channels;
+            stepx = PNG_PASS_COL_OFFSET(pass) * channels;
+            y = PNG_PASS_START_ROW(pass);
+            stepy = PNG_PASS_ROW_OFFSET(pass);
+         }
+
+         else
+         {
+            y = 0;
+            startx = 0;
+            stepx = channels;
+            stepy = 1;
+         }
+
+         for (; y<height; y += stepy)
+         {
+            png_bytep inrow = png_voidcast(png_bytep, display->local_row);
+            png_bytep outrow;
+            png_const_bytep end_row;
+
+            /* Read the row, which is packed: */
+            png_read_row(png_ptr, inrow, NULL);
+
+            outrow = png_voidcast(png_bytep, display->first_row);
+            outrow += y * step_row;
+            end_row = outrow + width * channels;
+
+            /* Now do the composition on each pixel in this row. */
+            outrow += startx;
+            for (; outrow < end_row; outrow += stepx)
+            {
+               png_byte alpha = inrow[channels];
+
+               if (alpha > 0) /* else no change to the output */
+               {
+                  unsigned int c;
+
+                  for (c=0; c<channels; ++c)
+                  {
+                     png_uint_32 component = inrow[c];
+
+                     if (alpha < 255) /* else just use component */
+                     {
+                        /* This is PNG_OPTIMIZED_ALPHA, the component value
+                         * is a linear 8-bit value.  Combine this with the
+                         * current outrow[c] value which is sRGB encoded.
+                         * Arithmetic here is 16-bits to preserve the output
+                         * values correctly.
+                         */
+                        component *= 257*255; /* =65535 */
+                        component += (255-alpha)*png_sRGB_table[outrow[c]];
+
+                        /* So 'component' is scaled by 255*65535 and is
+                         * therefore appropriate for the sRGB to linear
+                         * conversion table.
+                         */
+                        component = PNG_sRGB_FROM_LINEAR(component);
+                     }
+
+                     outrow[c] = (png_byte)component;
+                  }
+               }
+
+               inrow += channels+1; /* components and alpha channel */
+            }
+         }
+      }
+   }
+
+   return 1;
+}
+
+/* The do_local_background case; called when all the following transforms are to
+ * be done:
+ *
+ * PNG_RGB_TO_GRAY
+ * PNG_COMPOSITE
+ * PNG_GAMMA
+ *
+ * This is a work-around for the fact that both the PNG_RGB_TO_GRAY and
+ * PNG_COMPOSITE code performs gamma correction, so we get double gamma
+ * correction.  The fix-up is to prevent the PNG_COMPOSITE operation from
+ * happening inside libpng, so this routine sees an 8 or 16-bit gray+alpha
+ * row and handles the removal or pre-multiplication of the alpha channel.
+ */
+static int
+png_image_read_background(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_inforp info_ptr = image->opaque->info_ptr;
+   png_uint_32 height = image->height;
+   png_uint_32 width = image->width;
+   int pass, passes;
+
+   /* Double check the convoluted logic below.  We expect to get here with
+    * libpng doing rgb to gray and gamma correction but background processing
+    * left to the png_image_read_background function.  The rows libpng produce
+    * might be 8 or 16-bit but should always have two channels; gray plus alpha.
+    */
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+      png_error(png_ptr, "lost rgb to gray");
+
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+      png_error(png_ptr, "unexpected compose");
+
+   if (png_get_channels(png_ptr, info_ptr) != 2)
+      png_error(png_ptr, "lost/gained channels");
+
+   /* Expect the 8-bit case to always remove the alpha channel */
+   if ((image->format & PNG_FORMAT_FLAG_LINEAR) == 0 &&
+      (image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+      png_error(png_ptr, "unexpected 8-bit transformation");
+
+   switch (png_ptr->interlaced)
+   {
+      case PNG_INTERLACE_NONE:
+         passes = 1;
+         break;
+
+      case PNG_INTERLACE_ADAM7:
+         passes = PNG_INTERLACE_ADAM7_PASSES;
+         break;
+
+      default:
+         png_error(png_ptr, "unknown interlace type");
+   }
+
+   /* Use direct access to info_ptr here because otherwise the simplified API
+    * would require PNG_EASY_ACCESS_SUPPORTED (just for this.)  Note this is
+    * checking the value after libpng expansions, not the original value in the
+    * PNG.
+    */
+   switch (info_ptr->bit_depth)
+   {
+      case 8:
+         /* 8-bit sRGB gray values with an alpha channel; the alpha channel is
+          * to be removed by composing on a background: either the row if
+          * display->background is NULL or display->background->green if not.
+          * Unlike the code above ALPHA_OPTIMIZED has *not* been done.
+          */
+         {
+            png_bytep first_row = png_voidcast(png_bytep, display->first_row);
+            ptrdiff_t step_row = display->row_bytes;
+
+            for (pass = 0; pass < passes; ++pass)
+            {
+               unsigned int     startx, stepx, stepy;
+               png_uint_32      y;
+
+               if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+               {
+                  /* The row may be empty for a short image: */
+                  if (PNG_PASS_COLS(width, pass) == 0)
+                     continue;
+
+                  startx = PNG_PASS_START_COL(pass);
+                  stepx = PNG_PASS_COL_OFFSET(pass);
+                  y = PNG_PASS_START_ROW(pass);
+                  stepy = PNG_PASS_ROW_OFFSET(pass);
+               }
+
+               else
+               {
+                  y = 0;
+                  startx = 0;
+                  stepx = stepy = 1;
+               }
+
+               if (display->background == NULL)
+               {
+                  for (; y<height; y += stepy)
+                  {
+                     png_bytep inrow = png_voidcast(png_bytep,
+                         display->local_row);
+                     png_bytep outrow = first_row + y * step_row;
+                     png_const_bytep end_row = outrow + width;
+
+                     /* Read the row, which is packed: */
+                     png_read_row(png_ptr, inrow, NULL);
+
+                     /* Now do the composition on each pixel in this row. */
+                     outrow += startx;
+                     for (; outrow < end_row; outrow += stepx)
+                     {
+                        png_byte alpha = inrow[1];
+
+                        if (alpha > 0) /* else no change to the output */
+                        {
+                           png_uint_32 component = inrow[0];
+
+                           if (alpha < 255) /* else just use component */
+                           {
+                              /* Since PNG_OPTIMIZED_ALPHA was not set it is
+                               * necessary to invert the sRGB transfer
+                               * function and multiply the alpha out.
+                               */
+                              component = png_sRGB_table[component] * alpha;
+                              component += png_sRGB_table[outrow[0]] *
+                                 (255-alpha);
+                              component = PNG_sRGB_FROM_LINEAR(component);
+                           }
+
+                           outrow[0] = (png_byte)component;
+                        }
+
+                        inrow += 2; /* gray and alpha channel */
+                     }
+                  }
+               }
+
+               else /* constant background value */
+               {
+                  png_byte background8 = display->background->green;
+                  png_uint_16 background = png_sRGB_table[background8];
+
+                  for (; y<height; y += stepy)
+                  {
+                     png_bytep inrow = png_voidcast(png_bytep,
+                         display->local_row);
+                     png_bytep outrow = first_row + y * step_row;
+                     png_const_bytep end_row = outrow + width;
+
+                     /* Read the row, which is packed: */
+                     png_read_row(png_ptr, inrow, NULL);
+
+                     /* Now do the composition on each pixel in this row. */
+                     outrow += startx;
+                     for (; outrow < end_row; outrow += stepx)
+                     {
+                        png_byte alpha = inrow[1];
+
+                        if (alpha > 0) /* else use background */
+                        {
+                           png_uint_32 component = inrow[0];
+
+                           if (alpha < 255) /* else just use component */
+                           {
+                              component = png_sRGB_table[component] * alpha;
+                              component += background * (255-alpha);
+                              component = PNG_sRGB_FROM_LINEAR(component);
+                           }
+
+                           outrow[0] = (png_byte)component;
+                        }
+
+                        else
+                           outrow[0] = background8;
+
+                        inrow += 2; /* gray and alpha channel */
+                     }
+                  }
+               }
+            }
+         }
+         break;
+
+      case 16:
+         /* 16-bit linear with pre-multiplied alpha; the pre-multiplication must
+          * still be done and, maybe, the alpha channel removed.  This code also
+          * handles the alpha-first option.
+          */
+         {
+            png_uint_16p first_row = png_voidcast(png_uint_16p,
+                display->first_row);
+            /* The division by two is safe because the caller passed in a
+             * stride which was multiplied by 2 (below) to get row_bytes.
+             */
+            ptrdiff_t    step_row = display->row_bytes / 2;
+            unsigned int preserve_alpha = (image->format &
+                PNG_FORMAT_FLAG_ALPHA) != 0;
+            unsigned int outchannels = 1U+preserve_alpha;
+            int swap_alpha = 0;
+
+#           ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
+               if (preserve_alpha != 0 &&
+                   (image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+                  swap_alpha = 1;
+#           endif
+
+            for (pass = 0; pass < passes; ++pass)
+            {
+               unsigned int     startx, stepx, stepy;
+               png_uint_32      y;
+
+               /* The 'x' start and step are adjusted to output components here.
+                */
+               if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+               {
+                  /* The row may be empty for a short image: */
+                  if (PNG_PASS_COLS(width, pass) == 0)
+                     continue;
+
+                  startx = PNG_PASS_START_COL(pass) * outchannels;
+                  stepx = PNG_PASS_COL_OFFSET(pass) * outchannels;
+                  y = PNG_PASS_START_ROW(pass);
+                  stepy = PNG_PASS_ROW_OFFSET(pass);
+               }
+
+               else
+               {
+                  y = 0;
+                  startx = 0;
+                  stepx = outchannels;
+                  stepy = 1;
+               }
+
+               for (; y<height; y += stepy)
+               {
+                  png_const_uint_16p inrow;
+                  png_uint_16p outrow = first_row + y*step_row;
+                  png_uint_16p end_row = outrow + width * outchannels;
+
+                  /* Read the row, which is packed: */
+                  png_read_row(png_ptr, png_voidcast(png_bytep,
+                      display->local_row), NULL);
+                  inrow = png_voidcast(png_const_uint_16p, display->local_row);
+
+                  /* Now do the pre-multiplication on each pixel in this row.
+                   */
+                  outrow += startx;
+                  for (; outrow < end_row; outrow += stepx)
+                  {
+                     png_uint_32 component = inrow[0];
+                     png_uint_16 alpha = inrow[1];
+
+                     if (alpha > 0) /* else 0 */
+                     {
+                        if (alpha < 65535) /* else just use component */
+                        {
+                           component *= alpha;
+                           component += 32767;
+                           component /= 65535;
+                        }
+                     }
+
+                     else
+                        component = 0;
+
+                     outrow[swap_alpha] = (png_uint_16)component;
+                     if (preserve_alpha != 0)
+                        outrow[1 ^ swap_alpha] = alpha;
+
+                     inrow += 2; /* components and alpha channel */
+                  }
+               }
+            }
+         }
+         break;
+
+#ifdef __GNUC__
+      default:
+         png_error(png_ptr, "unexpected bit depth");
+#endif
+   }
+
+   return 1;
+}
+
+/* The guts of png_image_finish_read as a png_safe_execute callback. */
+static int
+png_image_read_direct(png_voidp argument)
+{
+   png_image_read_control *display = png_voidcast(png_image_read_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_inforp info_ptr = image->opaque->info_ptr;
+
+   png_uint_32 format = image->format;
+   int linear = (format & PNG_FORMAT_FLAG_LINEAR) != 0;
+   int do_local_compose = 0;
+   int do_local_background = 0; /* to avoid double gamma correction bug */
+   int passes = 0;
+
+   /* Add transforms to ensure the correct output format is produced then check
+    * that the required implementation support is there.  Always expand; always
+    * need 8 bits minimum, no palette and expanded tRNS.
+    */
+   png_set_expand(png_ptr);
+
+   /* Now check the format to see if it was modified. */
+   {
+      png_uint_32 base_format = png_image_format(png_ptr) &
+         ~PNG_FORMAT_FLAG_COLORMAP /* removed by png_set_expand */;
+      png_uint_32 change = format ^ base_format;
+      png_fixed_point output_gamma;
+      int mode; /* alpha mode */
+
+      /* Do this first so that we have a record if rgb to gray is happening. */
+      if ((change & PNG_FORMAT_FLAG_COLOR) != 0)
+      {
+         /* gray<->color transformation required. */
+         if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
+            png_set_gray_to_rgb(png_ptr);
+
+         else
+         {
+            /* libpng can't do both rgb to gray and
+             * background/pre-multiplication if there is also significant gamma
+             * correction, because both operations require linear colors and
+             * the code only supports one transform doing the gamma correction.
+             * Handle this by doing the pre-multiplication or background
+             * operation in this code, if necessary.
+             *
+             * TODO: fix this by rewriting pngrtran.c (!)
+             *
+             * For the moment (given that fixing this in pngrtran.c is an
+             * enormous change) 'do_local_background' is used to indicate that
+             * the problem exists.
+             */
+            if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+               do_local_background = 1/*maybe*/;
+
+            png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
+                PNG_RGB_TO_GRAY_DEFAULT, PNG_RGB_TO_GRAY_DEFAULT);
+         }
+
+         change &= ~PNG_FORMAT_FLAG_COLOR;
+      }
+
+      /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise.
+       */
+      {
+         png_fixed_point input_gamma_default;
+
+         if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
+             (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+            input_gamma_default = PNG_GAMMA_LINEAR;
+         else
+            input_gamma_default = PNG_DEFAULT_sRGB;
+
+         /* Call png_set_alpha_mode to set the default for the input gamma; the
+          * output gamma is set by a second call below.
+          */
+         png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, input_gamma_default);
+      }
+
+      if (linear != 0)
+      {
+         /* If there *is* an alpha channel in the input it must be multiplied
+          * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG.
+          */
+         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            mode = PNG_ALPHA_STANDARD; /* associated alpha */
+
+         else
+            mode = PNG_ALPHA_PNG;
+
+         output_gamma = PNG_GAMMA_LINEAR;
+      }
+
+      else
+      {
+         mode = PNG_ALPHA_PNG;
+         output_gamma = PNG_DEFAULT_sRGB;
+      }
+
+      if ((change & PNG_FORMAT_FLAG_ASSOCIATED_ALPHA) != 0)
+      {
+         mode = PNG_ALPHA_OPTIMIZED;
+         change &= ~PNG_FORMAT_FLAG_ASSOCIATED_ALPHA;
+      }
+
+      /* If 'do_local_background' is set check for the presence of gamma
+       * correction; this is part of the work-round for the libpng bug
+       * described above.
+       *
+       * TODO: fix libpng and remove this.
+       */
+      if (do_local_background != 0)
+      {
+         png_fixed_point gtest;
+
+         /* This is 'png_gamma_threshold' from pngrtran.c; the test used for
+          * gamma correction, the screen gamma hasn't been set on png_struct
+          * yet; it's set below.  png_struct::gamma, however, is set to the
+          * final value.
+          */
+         if (png_muldiv(&gtest, output_gamma, png_ptr->colorspace.gamma,
+             PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0)
+            do_local_background = 0;
+
+         else if (mode == PNG_ALPHA_STANDARD)
+         {
+            do_local_background = 2/*required*/;
+            mode = PNG_ALPHA_PNG; /* prevent libpng doing it */
+         }
+
+         /* else leave as 1 for the checks below */
+      }
+
+      /* If the bit-depth changes then handle that here. */
+      if ((change & PNG_FORMAT_FLAG_LINEAR) != 0)
+      {
+         if (linear != 0 /*16-bit output*/)
+            png_set_expand_16(png_ptr);
+
+         else /* 8-bit output */
+            png_set_scale_16(png_ptr);
+
+         change &= ~PNG_FORMAT_FLAG_LINEAR;
+      }
+
+      /* Now the background/alpha channel changes. */
+      if ((change & PNG_FORMAT_FLAG_ALPHA) != 0)
+      {
+         /* Removing an alpha channel requires composition for the 8-bit
+          * formats; for the 16-bit it is already done, above, by the
+          * pre-multiplication and the channel just needs to be stripped.
+          */
+         if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+         {
+            /* If RGB->gray is happening the alpha channel must be left and the
+             * operation completed locally.
+             *
+             * TODO: fix libpng and remove this.
+             */
+            if (do_local_background != 0)
+               do_local_background = 2/*required*/;
+
+            /* 16-bit output: just remove the channel */
+            else if (linear != 0) /* compose on black (well, pre-multiply) */
+               png_set_strip_alpha(png_ptr);
+
+            /* 8-bit output: do an appropriate compose */
+            else if (display->background != NULL)
+            {
+               png_color_16 c;
+
+               c.index = 0; /*unused*/
+               c.red = display->background->red;
+               c.green = display->background->green;
+               c.blue = display->background->blue;
+               c.gray = display->background->green;
+
+               /* This is always an 8-bit sRGB value, using the 'green' channel
+                * for gray is much better than calculating the luminance here;
+                * we can get off-by-one errors in that calculation relative to
+                * the app expectations and that will show up in transparent
+                * pixels.
+                */
+               png_set_background_fixed(png_ptr, &c,
+                   PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+                   0/*gamma: not used*/);
+            }
+
+            else /* compose on row: implemented below. */
+            {
+               do_local_compose = 1;
+               /* This leaves the alpha channel in the output, so it has to be
+                * removed by the code below.  Set the encoding to the 'OPTIMIZE'
+                * one so the code only has to hack on the pixels that require
+                * composition.
+                */
+               mode = PNG_ALPHA_OPTIMIZED;
+            }
+         }
+
+         else /* output needs an alpha channel */
+         {
+            /* This is tricky because it happens before the swap operation has
+             * been accomplished; however, the swap does *not* swap the added
+             * alpha channel (weird API), so it must be added in the correct
+             * place.
+             */
+            png_uint_32 filler; /* opaque filler */
+            int where;
+
+            if (linear != 0)
+               filler = 65535;
+
+            else
+               filler = 255;
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+            if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+            {
+               where = PNG_FILLER_BEFORE;
+               change &= ~PNG_FORMAT_FLAG_AFIRST;
+            }
+
+            else
+#endif
+            where = PNG_FILLER_AFTER;
+
+            png_set_add_alpha(png_ptr, filler, where);
+         }
+
+         /* This stops the (irrelevant) call to swap_alpha below. */
+         change &= ~PNG_FORMAT_FLAG_ALPHA;
+      }
+
+      /* Now set the alpha mode correctly; this is always done, even if there is
+       * no alpha channel in either the input or the output because it correctly
+       * sets the output gamma.
+       */
+      png_set_alpha_mode_fixed(png_ptr, mode, output_gamma);
+
+#     ifdef PNG_FORMAT_BGR_SUPPORTED
+         if ((change & PNG_FORMAT_FLAG_BGR) != 0)
+         {
+            /* Check only the output format; PNG is never BGR; don't do this if
+             * the output is gray, but fix up the 'format' value in that case.
+             */
+            if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
+               png_set_bgr(png_ptr);
+
+            else
+               format &= ~PNG_FORMAT_FLAG_BGR;
+
+            change &= ~PNG_FORMAT_FLAG_BGR;
+         }
+#     endif
+
+#     ifdef PNG_FORMAT_AFIRST_SUPPORTED
+         if ((change & PNG_FORMAT_FLAG_AFIRST) != 0)
+         {
+            /* Only relevant if there is an alpha channel - it's particularly
+             * important to handle this correctly because do_local_compose may
+             * be set above and then libpng will keep the alpha channel for this
+             * code to remove.
+             */
+            if ((format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            {
+               /* Disable this if doing a local background,
+                * TODO: remove this when local background is no longer required.
+                */
+               if (do_local_background != 2)
+                  png_set_swap_alpha(png_ptr);
+            }
+
+            else
+               format &= ~PNG_FORMAT_FLAG_AFIRST;
+
+            change &= ~PNG_FORMAT_FLAG_AFIRST;
+         }
+#     endif
+
+      /* If the *output* is 16-bit then we need to check for a byte-swap on this
+       * architecture.
+       */
+      if (linear != 0)
+      {
+         png_uint_16 le = 0x0001;
+
+         if ((*(png_const_bytep) & le) != 0)
+            png_set_swap(png_ptr);
+      }
+
+      /* If change is not now 0 some transformation is missing - error out. */
+      if (change != 0)
+         png_error(png_ptr, "png_read_image: unsupported transformation");
+   }
+
+   PNG_SKIP_CHUNKS(png_ptr);
+
+   /* Update the 'info' structure and make sure the result is as required; first
+    * make sure to turn on the interlace handling if it will be required
+    * (because it can't be turned on *after* the call to png_read_update_info!)
+    *
+    * TODO: remove the do_local_background fixup below.
+    */
+   if (do_local_compose == 0 && do_local_background != 2)
+      passes = png_set_interlace_handling(png_ptr);
+
+   png_read_update_info(png_ptr, info_ptr);
+
+   {
+      png_uint_32 info_format = 0;
+
+      if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+         info_format |= PNG_FORMAT_FLAG_COLOR;
+
+      if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      {
+         /* do_local_compose removes this channel below. */
+         if (do_local_compose == 0)
+         {
+            /* do_local_background does the same if required. */
+            if (do_local_background != 2 ||
+               (format & PNG_FORMAT_FLAG_ALPHA) != 0)
+               info_format |= PNG_FORMAT_FLAG_ALPHA;
+         }
+      }
+
+      else if (do_local_compose != 0) /* internal error */
+         png_error(png_ptr, "png_image_read: alpha channel lost");
+
+      if ((format & PNG_FORMAT_FLAG_ASSOCIATED_ALPHA) != 0) {
+         info_format |= PNG_FORMAT_FLAG_ASSOCIATED_ALPHA;
+      }
+
+      if (info_ptr->bit_depth == 16)
+         info_format |= PNG_FORMAT_FLAG_LINEAR;
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+      if ((png_ptr->transformations & PNG_BGR) != 0)
+         info_format |= PNG_FORMAT_FLAG_BGR;
+#endif
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+         if (do_local_background == 2)
+         {
+            if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+               info_format |= PNG_FORMAT_FLAG_AFIRST;
+         }
+
+         if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0 ||
+            ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 &&
+            (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0))
+         {
+            if (do_local_background == 2)
+               png_error(png_ptr, "unexpected alpha swap transformation");
+
+            info_format |= PNG_FORMAT_FLAG_AFIRST;
+         }
+#     endif
+
+      /* This is actually an internal error. */
+      if (info_format != format)
+         png_error(png_ptr, "png_read_image: invalid transformations");
+   }
+
+   /* Now read the rows.  If do_local_compose is set then it is necessary to use
+    * a local row buffer.  The output will be GA, RGBA or BGRA and must be
+    * converted to G, RGB or BGR as appropriate.  The 'local_row' member of the
+    * display acts as a flag.
+    */
+   {
+      png_voidp first_row = display->buffer;
+      ptrdiff_t row_bytes = display->row_stride;
+
+      if (linear != 0)
+         row_bytes *= 2;
+
+      /* The following expression is designed to work correctly whether it gives
+       * a signed or an unsigned result.
+       */
+      if (row_bytes < 0)
+      {
+         char *ptr = png_voidcast(char*, first_row);
+         ptr += (image->height-1) * (-row_bytes);
+         first_row = png_voidcast(png_voidp, ptr);
+      }
+
+      display->first_row = first_row;
+      display->row_bytes = row_bytes;
+   }
+
+   if (do_local_compose != 0)
+   {
+      int result;
+      png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
+
+      display->local_row = row;
+      result = png_safe_execute(image, png_image_read_composite, display);
+      display->local_row = NULL;
+      png_free(png_ptr, row);
+
+      return result;
+   }
+
+   else if (do_local_background == 2)
+   {
+      int result;
+      png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
+
+      display->local_row = row;
+      result = png_safe_execute(image, png_image_read_background, display);
+      display->local_row = NULL;
+      png_free(png_ptr, row);
+
+      return result;
+   }
+
+   else
+   {
+      png_alloc_size_t row_bytes = (png_alloc_size_t)display->row_bytes;
+
+      while (--passes >= 0)
+      {
+         png_uint_32      y = image->height;
+         png_bytep        row = png_voidcast(png_bytep, display->first_row);
+
+         for (; y > 0; --y)
+         {
+            png_read_row(png_ptr, row, NULL);
+            row += row_bytes;
+         }
+      }
+
+      return 1;
+   }
+}
+
+int PNGAPI
+png_image_finish_read(png_imagep image, png_const_colorp background,
+    void *buffer, png_int_32 row_stride, void *colormap)
+{
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      /* Check for row_stride overflow.  This check is not performed on the
+       * original PNG format because it may not occur in the output PNG format
+       * and libpng deals with the issues of reading the original.
+       */
+      unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
+
+      /* The following checks just the 'row_stride' calculation to ensure it
+       * fits in a signed 32-bit value.  Because channels/components can be
+       * either 1 or 2 bytes in size the length of a row can still overflow 32
+       * bits; this is just to verify that the 'row_stride' argument can be
+       * represented.
+       */
+      if (image->width <= 0x7fffffffU/channels) /* no overflow */
+      {
+         png_uint_32 check;
+         png_uint_32 png_row_stride = image->width * channels;
+
+         if (row_stride == 0)
+            row_stride = (png_int_32)/*SAFE*/png_row_stride;
+
+         if (row_stride < 0)
+            check = (png_uint_32)(-row_stride);
+
+         else
+            check = (png_uint_32)row_stride;
+
+         /* This verifies 'check', the absolute value of the actual stride
+          * passed in and detects overflow in the application calculation (i.e.
+          * if the app did actually pass in a non-zero 'row_stride'.
+          */
+         if (image->opaque != NULL && buffer != NULL && check >= png_row_stride)
+         {
+            /* Now check for overflow of the image buffer calculation; this
+             * limits the whole image size to 32 bits for API compatibility with
+             * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
+             *
+             * The PNG_IMAGE_BUFFER_SIZE macro is:
+             *
+             *    (PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)*height*(row_stride))
+             *
+             * And the component size is always 1 or 2, so make sure that the
+             * number of *bytes* that the application is saying are available
+             * does actually fit into a 32-bit number.
+             *
+             * NOTE: this will be changed in 1.7 because PNG_IMAGE_BUFFER_SIZE
+             * will be changed to use png_alloc_size_t; bigger images can be
+             * accommodated on 64-bit systems.
+             */
+            if (image->height <=
+                0xffffffffU/PNG_IMAGE_PIXEL_COMPONENT_SIZE(image->format)/check)
+            {
+               if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 ||
+                  (image->colormap_entries > 0 && colormap != NULL))
+               {
+                  int result;
+                  png_image_read_control display;
+
+                  memset(&display, 0, (sizeof display));
+                  display.image = image;
+                  display.buffer = buffer;
+                  display.row_stride = row_stride;
+                  display.colormap = colormap;
+                  display.background = background;
+                  display.local_row = NULL;
+
+                  /* Choose the correct 'end' routine; for the color-map case
+                   * all the setup has already been done.
+                   */
+                  if ((image->format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+                     result =
+                         png_safe_execute(image,
+                             png_image_read_colormap, &display) &&
+                             png_safe_execute(image,
+                             png_image_read_colormapped, &display);
+
+                  else
+                     result =
+                        png_safe_execute(image,
+                            png_image_read_direct, &display);
+
+                  png_image_free(image);
+                  return result;
+               }
+
+               else
+                  return png_image_error(image,
+                      "png_image_finish_read[color-map]: no color-map");
+            }
+
+            else
+               return png_image_error(image,
+                   "png_image_finish_read: image too large");
+         }
+
+         else
+            return png_image_error(image,
+                "png_image_finish_read: invalid argument");
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_finish_read: row_stride too large");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_finish_read: damaged PNG_IMAGE_VERSION");
+
+   return 0;
+}
+
+#endif /* SIMPLIFIED_READ */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/pngrio.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngrio.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngrio.c	(revision 107811)
@@ -0,0 +1,120 @@
+
+/* pngrio.c - functions for data input
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all input.  Users who need
+ * special handling are expected to write a function that has the same
+ * arguments as this and performs a similar function, but that possibly
+ * has a different input method.  Note that you shouldn't change this
+ * function, but rather write a replacement function and then make
+ * libpng use it at run time with png_set_read_fn(...).
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Read the data from whatever input you are using.  The default routine
+ * reads from a file pointer.  Note that this routine sometimes gets called
+ * with very small lengths, so you should implement some kind of simple
+ * buffering if you are using unbuffered reads.  This should never be asked
+ * to read more than 64K on a 16-bit machine.
+ */
+void /* PRIVATE */
+png_read_data(png_structrp png_ptr, png_bytep data, size_t length)
+{
+   png_debug1(4, "reading %d bytes", (int)length);
+
+   if (png_ptr->read_data_fn != NULL)
+      (*(png_ptr->read_data_fn))(png_ptr, data, length);
+
+   else
+      png_error(png_ptr, "Call to NULL read function");
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+/* This is the function that does the actual reading of data.  If you are
+ * not reading from a standard C stream, you should create a replacement
+ * read_data function and use it at run time with png_set_read_fn(), rather
+ * than changing the library.
+ */
+void PNGCBAPI
+png_default_read_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check;
+
+   if (png_ptr == NULL)
+      return;
+
+   /* fread() returns 0 on error, so it is OK to store this in a size_t
+    * instead of an int, which is what fread() actually returns.
+    */
+   check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr));
+
+   if (check != length)
+      png_error(png_ptr, "Read Error");
+}
+#endif
+
+/* This function allows the application to supply a new input function
+ * for libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ *
+ * png_ptr      - pointer to a png input data structure
+ *
+ * io_ptr       - pointer to user supplied structure containing info about
+ *                the input functions.  May be NULL.
+ *
+ * read_data_fn - pointer to a new input function that takes as its
+ *                arguments a pointer to a png_struct, a pointer to
+ *                a location where input data can be stored, and a 32-bit
+ *                unsigned int that is the number of bytes to be read.
+ *                To exit and output any fatal error messages the new write
+ *                function should call png_error(png_ptr, "Error msg").
+ *                May be NULL, in which case libpng's default function will
+ *                be used.
+ */
+void PNGAPI
+png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr,
+    png_rw_ptr read_data_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->io_ptr = io_ptr;
+
+#ifdef PNG_STDIO_SUPPORTED
+   if (read_data_fn != NULL)
+      png_ptr->read_data_fn = read_data_fn;
+
+   else
+      png_ptr->read_data_fn = png_default_read_data;
+#else
+   png_ptr->read_data_fn = read_data_fn;
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+   /* It is an error to write to a read device */
+   if (png_ptr->write_data_fn != NULL)
+   {
+      png_ptr->write_data_fn = NULL;
+      png_warning(png_ptr,
+          "Can't set both read_data_fn and write_data_fn in the"
+          " same structure");
+   }
+#endif
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+   png_ptr->output_flush_fn = NULL;
+#endif
+}
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/pngrtran.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngrtran.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngrtran.c	(revision 107811)
@@ -0,0 +1,5040 @@
+
+/* pngrtran.c - transforms the data in a row for PNG readers
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file contains functions optionally called by an application
+ * in order to tell libpng how to handle data when reading a PNG.
+ * Transformations that are used in both reading and writing are
+ * in pngtrans.c.
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_ARM_NEON_IMPLEMENTATION
+#  if PNG_ARM_NEON_IMPLEMENTATION == 1
+#    define PNG_ARM_NEON_INTRINSICS_AVAILABLE
+#    if defined(_MSC_VER) && !defined(__clang__) && defined(_M_ARM64)
+#      include <arm64_neon.h>
+#    else
+#      include <arm_neon.h>
+#    endif
+#  endif
+#endif
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Set the action on getting a CRC error for an ancillary or critical chunk. */
+void PNGAPI
+png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
+{
+   png_debug(1, "in png_set_crc_action");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* Tell libpng how we react to CRC errors in critical chunks */
+   switch (crit_action)
+   {
+      case PNG_CRC_NO_CHANGE:                        /* Leave setting as is */
+         break;
+
+      case PNG_CRC_WARN_USE:                               /* Warn/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
+         break;
+
+      case PNG_CRC_QUIET_USE:                             /* Quiet/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
+                           PNG_FLAG_CRC_CRITICAL_IGNORE;
+         break;
+
+      case PNG_CRC_WARN_DISCARD:    /* Not a valid action for critical data */
+         png_warning(png_ptr,
+             "Can't discard critical data on CRC error");
+         /* FALLTHROUGH */
+      case PNG_CRC_ERROR_QUIT:                                /* Error/quit */
+
+      case PNG_CRC_DEFAULT:
+      default:
+         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+         break;
+   }
+
+   /* Tell libpng how we react to CRC errors in ancillary chunks */
+   switch (ancil_action)
+   {
+      case PNG_CRC_NO_CHANGE:                       /* Leave setting as is */
+         break;
+
+      case PNG_CRC_WARN_USE:                              /* Warn/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
+         break;
+
+      case PNG_CRC_QUIET_USE:                            /* Quiet/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
+                           PNG_FLAG_CRC_ANCILLARY_NOWARN;
+         break;
+
+      case PNG_CRC_ERROR_QUIT:                               /* Error/quit */
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
+         break;
+
+      case PNG_CRC_WARN_DISCARD:                      /* Warn/discard data */
+
+      case PNG_CRC_DEFAULT:
+      default:
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         break;
+   }
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Is it OK to set a transformation now?  Only if png_start_read_image or
+ * png_read_update_info have not been called.  It is not necessary for the IHDR
+ * to have been read in all cases; the need_IHDR parameter allows for this
+ * check too.
+ */
+static int
+png_rtran_ok(png_structrp png_ptr, int need_IHDR)
+{
+   if (png_ptr != NULL)
+   {
+      if ((png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
+         png_app_error(png_ptr,
+             "invalid after png_start_read_image or png_read_update_info");
+
+      else if (need_IHDR && (png_ptr->mode & PNG_HAVE_IHDR) == 0)
+         png_app_error(png_ptr, "invalid before the PNG header has been read");
+
+      else
+      {
+         /* Turn on failure to initialize correctly for all transforms. */
+         png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
+
+         return 1; /* Ok */
+      }
+   }
+
+   return 0; /* no png_error possible! */
+}
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* Handle alpha and tRNS via a background color */
+void PNGFAPI
+png_set_background_fixed(png_structrp png_ptr,
+    png_const_color_16p background_color, int background_gamma_code,
+    int need_expand, png_fixed_point background_gamma)
+{
+   png_debug(1, "in png_set_background_fixed");
+
+   if (png_rtran_ok(png_ptr, 0) == 0 || background_color == NULL)
+      return;
+
+   if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
+   {
+      png_warning(png_ptr, "Application must supply a known background gamma");
+      return;
+   }
+
+   png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA;
+   png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+   png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+   png_ptr->background = *background_color;
+   png_ptr->background_gamma = background_gamma;
+   png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
+   if (need_expand != 0)
+      png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
+   else
+      png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_background(png_structrp png_ptr,
+    png_const_color_16p background_color, int background_gamma_code,
+    int need_expand, double background_gamma)
+{
+   png_set_background_fixed(png_ptr, background_color, background_gamma_code,
+      need_expand, png_fixed(png_ptr, background_gamma, "png_set_background"));
+}
+#  endif /* FLOATING_POINT */
+#endif /* READ_BACKGROUND */
+
+/* Scale 16-bit depth files to 8-bit depth.  If both of these are set then the
+ * one that pngrtran does first (scale) happens.  This is necessary to allow the
+ * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
+ */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+void PNGAPI
+png_set_scale_16(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_scale_16");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_SCALE_16_TO_8;
+}
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+/* Chop 16-bit depth files to 8-bit depth */
+void PNGAPI
+png_set_strip_16(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_strip_16");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_16_TO_8;
+}
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+void PNGAPI
+png_set_strip_alpha(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_strip_alpha");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_STRIP_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
+static png_fixed_point
+translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma,
+    int is_screen)
+{
+   /* Check for flag values.  The main reason for having the old Mac value as a
+    * flag is that it is pretty near impossible to work out what the correct
+    * value is from Apple documentation - a working Mac system is needed to
+    * discover the value!
+    */
+   if (output_gamma == PNG_DEFAULT_sRGB ||
+      output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
+   {
+      /* If there is no sRGB support this just sets the gamma to the standard
+       * sRGB value.  (This is a side effect of using this function!)
+       */
+#     ifdef PNG_READ_sRGB_SUPPORTED
+         png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
+#     else
+         PNG_UNUSED(png_ptr)
+#     endif
+      if (is_screen != 0)
+         output_gamma = PNG_GAMMA_sRGB;
+      else
+         output_gamma = PNG_GAMMA_sRGB_INVERSE;
+   }
+
+   else if (output_gamma == PNG_GAMMA_MAC_18 ||
+      output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
+   {
+      if (is_screen != 0)
+         output_gamma = PNG_GAMMA_MAC_OLD;
+      else
+         output_gamma = PNG_GAMMA_MAC_INVERSE;
+   }
+
+   return output_gamma;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+static png_fixed_point
+convert_gamma_value(png_structrp png_ptr, double output_gamma)
+{
+   /* The following silently ignores cases where fixed point (times 100,000)
+    * gamma values are passed to the floating point API.  This is safe and it
+    * means the fixed point constants work just fine with the floating point
+    * API.  The alternative would just lead to undetected errors and spurious
+    * bug reports.  Negative values fail inside the _fixed API unless they
+    * correspond to the flag values.
+    */
+   if (output_gamma > 0 && output_gamma < 128)
+      output_gamma *= PNG_FP_1;
+
+   /* This preserves -1 and -2 exactly: */
+   output_gamma = floor(output_gamma + .5);
+
+   if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
+      png_fixed_error(png_ptr, "gamma value");
+
+   return (png_fixed_point)output_gamma;
+}
+#  endif
+#endif /* READ_ALPHA_MODE || READ_GAMMA */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+void PNGFAPI
+png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
+    png_fixed_point output_gamma)
+{
+   int compose = 0;
+   png_fixed_point file_gamma;
+
+   png_debug(1, "in png_set_alpha_mode_fixed");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
+
+   /* Validate the value to ensure it is in a reasonable range.  The value
+    * is expected to be 1 or greater, but this range test allows for some
+    * viewing correction values.  The intent is to weed out the API users
+    * who might use the inverse of the gamma value accidentally!
+    *
+    * In libpng 1.6.0, we changed from 0.07..3 to 0.01..100, to accommodate
+    * the optimal 16-bit gamma of 36 and its reciprocal.
+    */
+   if (output_gamma < 1000 || output_gamma > 10000000)
+      png_error(png_ptr, "output gamma out of expected range");
+
+   /* The default file gamma is the inverse of the output gamma; the output
+    * gamma may be changed below so get the file value first:
+    */
+   file_gamma = png_reciprocal(output_gamma);
+
+   /* There are really 8 possibilities here, composed of any combination
+    * of:
+    *
+    *    premultiply the color channels
+    *    do not encode non-opaque pixels
+    *    encode the alpha as well as the color channels
+    *
+    * The differences disappear if the input/output ('screen') gamma is 1.0,
+    * because then the encoding is a no-op and there is only the choice of
+    * premultiplying the color channels or not.
+    *
+    * png_set_alpha_mode and png_set_background interact because both use
+    * png_compose to do the work.  Calling both is only useful when
+    * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
+    * with a default gamma value.  Otherwise PNG_COMPOSE must not be set.
+    */
+   switch (mode)
+   {
+      case PNG_ALPHA_PNG:        /* default: png standard */
+         /* No compose, but it may be set by png_set_background! */
+         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+         break;
+
+      case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
+         compose = 1;
+         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+         /* The output is linear: */
+         output_gamma = PNG_FP_1;
+         break;
+
+      case PNG_ALPHA_OPTIMIZED:  /* associated, non-opaque pixels linear */
+         compose = 1;
+         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+         png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
+         /* output_gamma records the encoding of opaque pixels! */
+         break;
+
+      case PNG_ALPHA_BROKEN:     /* associated, non-linear, alpha encoded */
+         compose = 1;
+         png_ptr->transformations |= PNG_ENCODE_ALPHA;
+         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+         break;
+
+      default:
+         png_error(png_ptr, "invalid alpha mode");
+   }
+
+   /* Only set the default gamma if the file gamma has not been set (this has
+    * the side effect that the gamma in a second call to png_set_alpha_mode will
+    * be ignored.)
+    */
+   if (png_ptr->colorspace.gamma == 0)
+   {
+      png_ptr->colorspace.gamma = file_gamma;
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+   }
+
+   /* But always set the output gamma: */
+   png_ptr->screen_gamma = output_gamma;
+
+   /* Finally, if pre-multiplying, set the background fields to achieve the
+    * desired result.
+    */
+   if (compose != 0)
+   {
+      /* And obtain alpha pre-multiplication by composing on black: */
+      memset(&png_ptr->background, 0, (sizeof png_ptr->background));
+      png_ptr->background_gamma = png_ptr->colorspace.gamma; /* just in case */
+      png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
+      png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
+
+      if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+         png_error(png_ptr,
+             "conflicting calls to set alpha mode and background");
+
+      png_ptr->transformations |= PNG_COMPOSE;
+   }
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma)
+{
+   png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
+       output_gamma));
+}
+#  endif
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* Dither file to 8-bit.  Supply a palette, the current number
+ * of elements in the palette, the maximum number of elements
+ * allowed, and a histogram if possible.  If the current number
+ * of colors is greater than the maximum number, the palette will be
+ * modified to fit in the maximum number.  "full_quantize" indicates
+ * whether we need a quantizing cube set up for RGB images, or if we
+ * simply are reducing the number of colors in a paletted image.
+ */
+
+typedef struct png_dsort_struct
+{
+   struct png_dsort_struct * next;
+   png_byte left;
+   png_byte right;
+} png_dsort;
+typedef png_dsort *   png_dsortp;
+typedef png_dsort * * png_dsortpp;
+
+void PNGAPI
+png_set_quantize(png_structrp png_ptr, png_colorp palette,
+    int num_palette, int maximum_colors, png_const_uint_16p histogram,
+    int full_quantize)
+{
+   png_debug(1, "in png_set_quantize");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_QUANTIZE;
+
+   if (full_quantize == 0)
+   {
+      int i;
+
+      png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
+          (png_alloc_size_t)num_palette);
+      for (i = 0; i < num_palette; i++)
+         png_ptr->quantize_index[i] = (png_byte)i;
+   }
+
+   if (num_palette > maximum_colors)
+   {
+      if (histogram != NULL)
+      {
+         /* This is easy enough, just throw out the least used colors.
+          * Perhaps not the best solution, but good enough.
+          */
+
+         int i;
+
+         /* Initialize an array to sort colors */
+         png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
+             (png_alloc_size_t)num_palette);
+
+         /* Initialize the quantize_sort array */
+         for (i = 0; i < num_palette; i++)
+            png_ptr->quantize_sort[i] = (png_byte)i;
+
+         /* Find the least used palette entries by starting a
+          * bubble sort, and running it until we have sorted
+          * out enough colors.  Note that we don't care about
+          * sorting all the colors, just finding which are
+          * least used.
+          */
+
+         for (i = num_palette - 1; i >= maximum_colors; i--)
+         {
+            int done; /* To stop early if the list is pre-sorted */
+            int j;
+
+            done = 1;
+            for (j = 0; j < i; j++)
+            {
+               if (histogram[png_ptr->quantize_sort[j]]
+                   < histogram[png_ptr->quantize_sort[j + 1]])
+               {
+                  png_byte t;
+
+                  t = png_ptr->quantize_sort[j];
+                  png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
+                  png_ptr->quantize_sort[j + 1] = t;
+                  done = 0;
+               }
+            }
+
+            if (done != 0)
+               break;
+         }
+
+         /* Swap the palette around, and set up a table, if necessary */
+         if (full_quantize != 0)
+         {
+            int j = num_palette;
+
+            /* Put all the useful colors within the max, but don't
+             * move the others.
+             */
+            for (i = 0; i < maximum_colors; i++)
+            {
+               if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
+               {
+                  do
+                     j--;
+                  while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
+
+                  palette[i] = palette[j];
+               }
+            }
+         }
+         else
+         {
+            int j = num_palette;
+
+            /* Move all the used colors inside the max limit, and
+             * develop a translation table.
+             */
+            for (i = 0; i < maximum_colors; i++)
+            {
+               /* Only move the colors we need to */
+               if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
+               {
+                  png_color tmp_color;
+
+                  do
+                     j--;
+                  while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
+
+                  tmp_color = palette[j];
+                  palette[j] = palette[i];
+                  palette[i] = tmp_color;
+                  /* Indicate where the color went */
+                  png_ptr->quantize_index[j] = (png_byte)i;
+                  png_ptr->quantize_index[i] = (png_byte)j;
+               }
+            }
+
+            /* Find closest color for those colors we are not using */
+            for (i = 0; i < num_palette; i++)
+            {
+               if ((int)png_ptr->quantize_index[i] >= maximum_colors)
+               {
+                  int min_d, k, min_k, d_index;
+
+                  /* Find the closest color to one we threw out */
+                  d_index = png_ptr->quantize_index[i];
+                  min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
+                  for (k = 1, min_k = 0; k < maximum_colors; k++)
+                  {
+                     int d;
+
+                     d = PNG_COLOR_DIST(palette[d_index], palette[k]);
+
+                     if (d < min_d)
+                     {
+                        min_d = d;
+                        min_k = k;
+                     }
+                  }
+                  /* Point to closest color */
+                  png_ptr->quantize_index[i] = (png_byte)min_k;
+               }
+            }
+         }
+         png_free(png_ptr, png_ptr->quantize_sort);
+         png_ptr->quantize_sort = NULL;
+      }
+      else
+      {
+         /* This is much harder to do simply (and quickly).  Perhaps
+          * we need to go through a median cut routine, but those
+          * don't always behave themselves with only a few colors
+          * as input.  So we will just find the closest two colors,
+          * and throw out one of them (chosen somewhat randomly).
+          * [We don't understand this at all, so if someone wants to
+          *  work on improving it, be our guest - AED, GRP]
+          */
+         int i;
+         int max_d;
+         int num_new_palette;
+         png_dsortp t;
+         png_dsortpp hash;
+
+         t = NULL;
+
+         /* Initialize palette index arrays */
+         png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
+             (png_alloc_size_t)num_palette);
+         png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
+             (png_alloc_size_t)num_palette);
+
+         /* Initialize the sort array */
+         for (i = 0; i < num_palette; i++)
+         {
+            png_ptr->index_to_palette[i] = (png_byte)i;
+            png_ptr->palette_to_index[i] = (png_byte)i;
+         }
+
+         hash = (png_dsortpp)png_calloc(png_ptr, (png_alloc_size_t)(769 *
+             (sizeof (png_dsortp))));
+
+         num_new_palette = num_palette;
+
+         /* Initial wild guess at how far apart the farthest pixel
+          * pair we will be eliminating will be.  Larger
+          * numbers mean more areas will be allocated, Smaller
+          * numbers run the risk of not saving enough data, and
+          * having to do this all over again.
+          *
+          * I have not done extensive checking on this number.
+          */
+         max_d = 96;
+
+         while (num_new_palette > maximum_colors)
+         {
+            for (i = 0; i < num_new_palette - 1; i++)
+            {
+               int j;
+
+               for (j = i + 1; j < num_new_palette; j++)
+               {
+                  int d;
+
+                  d = PNG_COLOR_DIST(palette[i], palette[j]);
+
+                  if (d <= max_d)
+                  {
+
+                     t = (png_dsortp)png_malloc_warn(png_ptr,
+                         (png_alloc_size_t)(sizeof (png_dsort)));
+
+                     if (t == NULL)
+                         break;
+
+                     t->next = hash[d];
+                     t->left = (png_byte)i;
+                     t->right = (png_byte)j;
+                     hash[d] = t;
+                  }
+               }
+               if (t == NULL)
+                  break;
+            }
+
+            if (t != NULL)
+            for (i = 0; i <= max_d; i++)
+            {
+               if (hash[i] != NULL)
+               {
+                  png_dsortp p;
+
+                  for (p = hash[i]; p; p = p->next)
+                  {
+                     if ((int)png_ptr->index_to_palette[p->left]
+                         < num_new_palette &&
+                         (int)png_ptr->index_to_palette[p->right]
+                         < num_new_palette)
+                     {
+                        int j, next_j;
+
+                        if (num_new_palette & 0x01)
+                        {
+                           j = p->left;
+                           next_j = p->right;
+                        }
+                        else
+                        {
+                           j = p->right;
+                           next_j = p->left;
+                        }
+
+                        num_new_palette--;
+                        palette[png_ptr->index_to_palette[j]]
+                            = palette[num_new_palette];
+                        if (full_quantize == 0)
+                        {
+                           int k;
+
+                           for (k = 0; k < num_palette; k++)
+                           {
+                              if (png_ptr->quantize_index[k] ==
+                                  png_ptr->index_to_palette[j])
+                                 png_ptr->quantize_index[k] =
+                                     png_ptr->index_to_palette[next_j];
+
+                              if ((int)png_ptr->quantize_index[k] ==
+                                  num_new_palette)
+                                 png_ptr->quantize_index[k] =
+                                     png_ptr->index_to_palette[j];
+                           }
+                        }
+
+                        png_ptr->index_to_palette[png_ptr->palette_to_index
+                            [num_new_palette]] = png_ptr->index_to_palette[j];
+
+                        png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
+                            = png_ptr->palette_to_index[num_new_palette];
+
+                        png_ptr->index_to_palette[j] =
+                            (png_byte)num_new_palette;
+
+                        png_ptr->palette_to_index[num_new_palette] =
+                            (png_byte)j;
+                     }
+                     if (num_new_palette <= maximum_colors)
+                        break;
+                  }
+                  if (num_new_palette <= maximum_colors)
+                     break;
+               }
+            }
+
+            for (i = 0; i < 769; i++)
+            {
+               if (hash[i] != NULL)
+               {
+                  png_dsortp p = hash[i];
+                  while (p)
+                  {
+                     t = p->next;
+                     png_free(png_ptr, p);
+                     p = t;
+                  }
+               }
+               hash[i] = 0;
+            }
+            max_d += 96;
+         }
+         png_free(png_ptr, hash);
+         png_free(png_ptr, png_ptr->palette_to_index);
+         png_free(png_ptr, png_ptr->index_to_palette);
+         png_ptr->palette_to_index = NULL;
+         png_ptr->index_to_palette = NULL;
+      }
+      num_palette = maximum_colors;
+   }
+   if (png_ptr->palette == NULL)
+   {
+      png_ptr->palette = palette;
+   }
+   png_ptr->num_palette = (png_uint_16)num_palette;
+
+   if (full_quantize != 0)
+   {
+      int i;
+      png_bytep distance;
+      int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
+          PNG_QUANTIZE_BLUE_BITS;
+      int num_red = (1 << PNG_QUANTIZE_RED_BITS);
+      int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
+      int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);
+      size_t num_entries = ((size_t)1 << total_bits);
+
+      png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr,
+          (png_alloc_size_t)(num_entries));
+
+      distance = (png_bytep)png_malloc(png_ptr, (png_alloc_size_t)num_entries);
+
+      memset(distance, 0xff, num_entries);
+
+      for (i = 0; i < num_palette; i++)
+      {
+         int ir, ig, ib;
+         int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
+         int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
+         int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS));
+
+         for (ir = 0; ir < num_red; ir++)
+         {
+            /* int dr = abs(ir - r); */
+            int dr = ((ir > r) ? ir - r : r - ir);
+            int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS +
+                PNG_QUANTIZE_GREEN_BITS));
+
+            for (ig = 0; ig < num_green; ig++)
+            {
+               /* int dg = abs(ig - g); */
+               int dg = ((ig > g) ? ig - g : g - ig);
+               int dt = dr + dg;
+               int dm = ((dr > dg) ? dr : dg);
+               int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS);
+
+               for (ib = 0; ib < num_blue; ib++)
+               {
+                  int d_index = index_g | ib;
+                  /* int db = abs(ib - b); */
+                  int db = ((ib > b) ? ib - b : b - ib);
+                  int dmax = ((dm > db) ? dm : db);
+                  int d = dmax + dt + db;
+
+                  if (d < (int)distance[d_index])
+                  {
+                     distance[d_index] = (png_byte)d;
+                     png_ptr->palette_lookup[d_index] = (png_byte)i;
+                  }
+               }
+            }
+         }
+      }
+
+      png_free(png_ptr, distance);
+   }
+}
+#endif /* READ_QUANTIZE */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+void PNGFAPI
+png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
+    png_fixed_point file_gamma)
+{
+   png_debug(1, "in png_set_gamma_fixed");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   /* New in libpng-1.5.4 - reserve particular negative values as flags. */
+   scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
+   file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
+
+   /* Checking the gamma values for being >0 was added in 1.5.4 along with the
+    * premultiplied alpha support; this actually hides an undocumented feature
+    * of the previous implementation which allowed gamma processing to be
+    * disabled in background handling.  There is no evidence (so far) that this
+    * was being used; however, png_set_background itself accepted and must still
+    * accept '0' for the gamma value it takes, because it isn't always used.
+    *
+    * Since this is an API change (albeit a very minor one that removes an
+    * undocumented API feature) the following checks were only enabled in
+    * libpng-1.6.0.
+    */
+   if (file_gamma <= 0)
+      png_error(png_ptr, "invalid file gamma in png_set_gamma");
+
+   if (scrn_gamma <= 0)
+      png_error(png_ptr, "invalid screen gamma in png_set_gamma");
+
+   /* Set the gamma values unconditionally - this overrides the value in the PNG
+    * file if a gAMA chunk was present.  png_set_alpha_mode provides a
+    * different, easier, way to default the file gamma.
+    */
+   png_ptr->colorspace.gamma = file_gamma;
+   png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+   png_ptr->screen_gamma = scrn_gamma;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_gamma(png_structrp png_ptr, double scrn_gamma, double file_gamma)
+{
+   png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
+       convert_gamma_value(png_ptr, file_gamma));
+}
+#  endif /* FLOATING_POINT */
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expand paletted images to RGB, expand grayscale images of
+ * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
+ * to alpha channels.
+ */
+void PNGAPI
+png_set_expand(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_expand");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+
+/* GRR 19990627:  the following three functions currently are identical
+ *  to png_set_expand().  However, it is entirely reasonable that someone
+ *  might wish to expand an indexed image to RGB but *not* expand a single,
+ *  fully transparent palette entry to a full alpha channel--perhaps instead
+ *  convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
+ *  the transparent color with a particular RGB value, or drop tRNS entirely.
+ *  IOW, a future version of the library may make the transformations flag
+ *  a bit more fine-grained, with separate bits for each of these three
+ *  functions.
+ *
+ *  More to the point, these functions make it obvious what libpng will be
+ *  doing, whereas "expand" can (and does) mean any number of things.
+ *
+ *  GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
+ *  to expand only the sample depth but not to expand the tRNS to alpha
+ *  and its name was changed to png_set_expand_gray_1_2_4_to_8().
+ */
+
+/* Expand paletted images to RGB. */
+void PNGAPI
+png_set_palette_to_rgb(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_palette_to_rgb");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+
+/* Expand grayscale images of less than 8-bit depth to 8 bits. */
+void PNGAPI
+png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= PNG_EXPAND;
+}
+
+/* Expand tRNS chunks to alpha channels. */
+void PNGAPI
+png_set_tRNS_to_alpha(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_tRNS_to_alpha");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+#endif /* READ_EXPAND */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
+ * it may not work correctly.)
+ */
+void PNGAPI
+png_set_expand_16(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_expand_16");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+void PNGAPI
+png_set_gray_to_rgb(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_gray_to_rgb");
+
+   if (png_rtran_ok(png_ptr, 0) == 0)
+      return;
+
+   /* Because rgb must be 8 bits or more: */
+   png_set_expand_gray_1_2_4_to_8(png_ptr);
+   png_ptr->transformations |= PNG_GRAY_TO_RGB;
+}
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+void PNGFAPI
+png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
+    png_fixed_point red, png_fixed_point green)
+{
+   png_debug(1, "in png_set_rgb_to_gray_fixed");
+
+   /* Need the IHDR here because of the check on color_type below. */
+   /* TODO: fix this */
+   if (png_rtran_ok(png_ptr, 1) == 0)
+      return;
+
+   switch (error_action)
+   {
+      case PNG_ERROR_ACTION_NONE:
+         png_ptr->transformations |= PNG_RGB_TO_GRAY;
+         break;
+
+      case PNG_ERROR_ACTION_WARN:
+         png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
+         break;
+
+      case PNG_ERROR_ACTION_ERROR:
+         png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
+         break;
+
+      default:
+         png_error(png_ptr, "invalid error action to rgb_to_gray");
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#ifdef PNG_READ_EXPAND_SUPPORTED
+      png_ptr->transformations |= PNG_EXPAND;
+#else
+   {
+      /* Make this an error in 1.6 because otherwise the application may assume
+       * that it just worked and get a memory overwrite.
+       */
+      png_error(png_ptr,
+          "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
+
+      /* png_ptr->transformations &= ~PNG_RGB_TO_GRAY; */
+   }
+#endif
+   {
+      if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
+      {
+         png_uint_16 red_int, green_int;
+
+         /* NOTE: this calculation does not round, but this behavior is retained
+          * for consistency; the inaccuracy is very small.  The code here always
+          * overwrites the coefficients, regardless of whether they have been
+          * defaulted or set already.
+          */
+         red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
+         green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
+
+         png_ptr->rgb_to_gray_red_coeff   = red_int;
+         png_ptr->rgb_to_gray_green_coeff = green_int;
+         png_ptr->rgb_to_gray_coefficients_set = 1;
+      }
+
+      else
+      {
+         if (red >= 0 && green >= 0)
+            png_app_warning(png_ptr,
+                "ignoring out of range rgb_to_gray coefficients");
+
+         /* Use the defaults, from the cHRM chunk if set, else the historical
+          * values which are close to the sRGB/HDTV/ITU-Rec 709 values.  See
+          * png_do_rgb_to_gray for more discussion of the values.  In this case
+          * the coefficients are not marked as 'set' and are not overwritten if
+          * something has already provided a default.
+          */
+         if (png_ptr->rgb_to_gray_red_coeff == 0 &&
+             png_ptr->rgb_to_gray_green_coeff == 0)
+         {
+            png_ptr->rgb_to_gray_red_coeff   = 6968;
+            png_ptr->rgb_to_gray_green_coeff = 23434;
+            /* png_ptr->rgb_to_gray_blue_coeff  = 2366; */
+         }
+      }
+   }
+}
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+/* Convert a RGB image to a grayscale of the same width.  This allows us,
+ * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
+ */
+
+void PNGAPI
+png_set_rgb_to_gray(png_structrp png_ptr, int error_action, double red,
+    double green)
+{
+   png_set_rgb_to_gray_fixed(png_ptr, error_action,
+       png_fixed(png_ptr, red, "rgb to gray red coefficient"),
+      png_fixed(png_ptr, green, "rgb to gray green coefficient"));
+}
+#endif /* FLOATING POINT */
+
+#endif /* RGB_TO_GRAY */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+void PNGAPI
+png_set_read_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
+    read_user_transform_fn)
+{
+   png_debug(1, "in png_set_read_user_transform_fn");
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   png_ptr->transformations |= PNG_USER_TRANSFORM;
+   png_ptr->read_user_transform_fn = read_user_transform_fn;
+#endif
+}
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* In the case of gamma transformations only do transformations on images where
+ * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
+ * slows things down slightly, and also needlessly introduces small errors.
+ */
+static int /* PRIVATE */
+png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
+{
+   /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
+    * correction as a difference of the overall transform from 1.0
+    *
+    * We want to compare the threshold with s*f - 1, if we get
+    * overflow here it is because of wacky gamma values so we
+    * turn on processing anyway.
+    */
+   png_fixed_point gtest;
+   return !png_muldiv(&gtest, screen_gamma, file_gamma, PNG_FP_1) ||
+       png_gamma_significant(gtest);
+}
+#endif
+
+/* Initialize everything needed for the read.  This includes modifying
+ * the palette.
+ */
+
+/* For the moment 'png_init_palette_transformations' and
+ * 'png_init_rgb_transformations' only do some flag canceling optimizations.
+ * The intent is that these two routines should have palette or rgb operations
+ * extracted from 'png_init_read_transformations'.
+ */
+static void /* PRIVATE */
+png_init_palette_transformations(png_structrp png_ptr)
+{
+   /* Called to handle the (input) palette case.  In png_do_read_transformations
+    * the first step is to expand the palette if requested, so this code must
+    * take care to only make changes that are invariant with respect to the
+    * palette expansion, or only do them if there is no expansion.
+    *
+    * STRIP_ALPHA has already been handled in the caller (by setting num_trans
+    * to 0.)
+    */
+   int input_has_alpha = 0;
+   int input_has_transparency = 0;
+
+   if (png_ptr->num_trans > 0)
+   {
+      int i;
+
+      /* Ignore if all the entries are opaque (unlikely!) */
+      for (i=0; i<png_ptr->num_trans; ++i)
+      {
+         if (png_ptr->trans_alpha[i] == 255)
+            continue;
+         else if (png_ptr->trans_alpha[i] == 0)
+            input_has_transparency = 1;
+         else
+         {
+            input_has_transparency = 1;
+            input_has_alpha = 1;
+            break;
+         }
+      }
+   }
+
+   /* If no alpha we can optimize. */
+   if (input_has_alpha == 0)
+   {
+      /* Any alpha means background and associative alpha processing is
+       * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
+       * and ENCODE_ALPHA are irrelevant.
+       */
+      png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+      if (input_has_transparency == 0)
+         png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
+   }
+
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* png_set_background handling - deals with the complexity of whether the
+    * background color is in the file format or the screen format in the case
+    * where an 'expand' will happen.
+    */
+
+   /* The following code cannot be entered in the alpha pre-multiplication case
+    * because PNG_BACKGROUND_EXPAND is cancelled below.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) != 0)
+   {
+      {
+         png_ptr->background.red   =
+             png_ptr->palette[png_ptr->background.index].red;
+         png_ptr->background.green =
+             png_ptr->palette[png_ptr->background.index].green;
+         png_ptr->background.blue  =
+             png_ptr->palette[png_ptr->background.index].blue;
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+         if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+         {
+            if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
+            {
+               /* Invert the alpha channel (in tRNS) unless the pixels are
+                * going to be expanded, in which case leave it for later
+                */
+               int i, istop = png_ptr->num_trans;
+
+               for (i = 0; i < istop; i++)
+                  png_ptr->trans_alpha[i] =
+                      (png_byte)(255 - png_ptr->trans_alpha[i]);
+            }
+         }
+#endif /* READ_INVERT_ALPHA */
+      }
+   } /* background expand and (therefore) no alpha association. */
+#endif /* READ_EXPAND && READ_BACKGROUND */
+}
+
+static void /* PRIVATE */
+png_init_rgb_transformations(png_structrp png_ptr)
+{
+   /* Added to libpng-1.5.4: check the color type to determine whether there
+    * is any alpha or transparency in the image and simply cancel the
+    * background and alpha mode stuff if there isn't.
+    */
+   int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
+   int input_has_transparency = png_ptr->num_trans > 0;
+
+   /* If no alpha we can optimize. */
+   if (input_has_alpha == 0)
+   {
+      /* Any alpha means background and associative alpha processing is
+       * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
+       * and ENCODE_ALPHA are irrelevant.
+       */
+#     ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+         png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+         png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+#     endif
+
+      if (input_has_transparency == 0)
+         png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
+   }
+
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* png_set_background handling - deals with the complexity of whether the
+    * background color is in the file format or the screen format in the case
+    * where an 'expand' will happen.
+    */
+
+   /* The following code cannot be entered in the alpha pre-multiplication case
+    * because PNG_BACKGROUND_EXPAND is cancelled below.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) != 0 &&
+       (png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+       /* i.e., GRAY or GRAY_ALPHA */
+   {
+      {
+         /* Expand background and tRNS chunks */
+         int gray = png_ptr->background.gray;
+         int trans_gray = png_ptr->trans_color.gray;
+
+         switch (png_ptr->bit_depth)
+         {
+            case 1:
+               gray *= 0xff;
+               trans_gray *= 0xff;
+               break;
+
+            case 2:
+               gray *= 0x55;
+               trans_gray *= 0x55;
+               break;
+
+            case 4:
+               gray *= 0x11;
+               trans_gray *= 0x11;
+               break;
+
+            default:
+
+            case 8:
+               /* FALLTHROUGH */ /*  (Already 8 bits) */
+
+            case 16:
+               /* Already a full 16 bits */
+               break;
+         }
+
+         png_ptr->background.red = png_ptr->background.green =
+            png_ptr->background.blue = (png_uint_16)gray;
+
+         if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
+         {
+            png_ptr->trans_color.red = png_ptr->trans_color.green =
+               png_ptr->trans_color.blue = (png_uint_16)trans_gray;
+         }
+      }
+   } /* background expand and (therefore) no alpha association. */
+#endif /* READ_EXPAND && READ_BACKGROUND */
+}
+
+void /* PRIVATE */
+png_init_read_transformations(png_structrp png_ptr)
+{
+   png_debug(1, "in png_init_read_transformations");
+
+   /* This internal function is called from png_read_start_row in pngrutil.c
+    * and it is called before the 'rowbytes' calculation is done, so the code
+    * in here can change or update the transformations flags.
+    *
+    * First do updates that do not depend on the details of the PNG image data
+    * being processed.
+    */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
+    * png_set_alpha_mode and this is another source for a default file gamma so
+    * the test needs to be performed later - here.  In addition prior to 1.5.4
+    * the tests were repeated for the PALETTE color type here - this is no
+    * longer necessary (and doesn't seem to have been necessary before.)
+    */
+   {
+      /* The following temporary indicates if overall gamma correction is
+       * required.
+       */
+      int gamma_correction = 0;
+
+      if (png_ptr->colorspace.gamma != 0) /* has been set */
+      {
+         if (png_ptr->screen_gamma != 0) /* screen set too */
+            gamma_correction = png_gamma_threshold(png_ptr->colorspace.gamma,
+                png_ptr->screen_gamma);
+
+         else
+            /* Assume the output matches the input; a long time default behavior
+             * of libpng, although the standard has nothing to say about this.
+             */
+            png_ptr->screen_gamma = png_reciprocal(png_ptr->colorspace.gamma);
+      }
+
+      else if (png_ptr->screen_gamma != 0)
+         /* The converse - assume the file matches the screen, note that this
+          * perhaps undesirable default can (from 1.5.4) be changed by calling
+          * png_set_alpha_mode (even if the alpha handling mode isn't required
+          * or isn't changed from the default.)
+          */
+         png_ptr->colorspace.gamma = png_reciprocal(png_ptr->screen_gamma);
+
+      else /* neither are set */
+         /* Just in case the following prevents any processing - file and screen
+          * are both assumed to be linear and there is no way to introduce a
+          * third gamma value other than png_set_background with 'UNIQUE', and,
+          * prior to 1.5.4
+          */
+         png_ptr->screen_gamma = png_ptr->colorspace.gamma = PNG_FP_1;
+
+      /* We have a gamma value now. */
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+
+      /* Now turn the gamma transformation on or off as appropriate.  Notice
+       * that PNG_GAMMA just refers to the file->screen correction.  Alpha
+       * composition may independently cause gamma correction because it needs
+       * linear data (e.g. if the file has a gAMA chunk but the screen gamma
+       * hasn't been specified.)  In any case this flag may get turned off in
+       * the code immediately below if the transform can be handled outside the
+       * row loop.
+       */
+      if (gamma_correction != 0)
+         png_ptr->transformations |= PNG_GAMMA;
+
+      else
+         png_ptr->transformations &= ~PNG_GAMMA;
+   }
+#endif
+
+   /* Certain transformations have the effect of preventing other
+    * transformations that happen afterward in png_do_read_transformations;
+    * resolve the interdependencies here.  From the code of
+    * png_do_read_transformations the order is:
+    *
+    *  1) PNG_EXPAND (including PNG_EXPAND_tRNS)
+    *  2) PNG_STRIP_ALPHA (if no compose)
+    *  3) PNG_RGB_TO_GRAY
+    *  4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
+    *  5) PNG_COMPOSE
+    *  6) PNG_GAMMA
+    *  7) PNG_STRIP_ALPHA (if compose)
+    *  8) PNG_ENCODE_ALPHA
+    *  9) PNG_SCALE_16_TO_8
+    * 10) PNG_16_TO_8
+    * 11) PNG_QUANTIZE (converts to palette)
+    * 12) PNG_EXPAND_16
+    * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
+    * 14) PNG_INVERT_MONO
+    * 15) PNG_INVERT_ALPHA
+    * 16) PNG_SHIFT
+    * 17) PNG_PACK
+    * 18) PNG_BGR
+    * 19) PNG_PACKSWAP
+    * 20) PNG_FILLER (includes PNG_ADD_ALPHA)
+    * 21) PNG_SWAP_ALPHA
+    * 22) PNG_SWAP_BYTES
+    * 23) PNG_USER_TRANSFORM [must be last]
+    */
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) == 0)
+   {
+      /* Stripping the alpha channel happens immediately after the 'expand'
+       * transformations, before all other transformation, so it cancels out
+       * the alpha handling.  It has the side effect negating the effect of
+       * PNG_EXPAND_tRNS too:
+       */
+      png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
+         PNG_EXPAND_tRNS);
+      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+      /* Kill the tRNS chunk itself too.  Prior to 1.5.4 this did not happen
+       * so transparency information would remain just so long as it wasn't
+       * expanded.  This produces unexpected API changes if the set of things
+       * that do PNG_EXPAND_tRNS changes (perfectly possible given the
+       * documentation - which says ask for what you want, accept what you
+       * get.)  This makes the behavior consistent from 1.5.4:
+       */
+      png_ptr->num_trans = 0;
+   }
+#endif /* STRIP_ALPHA supported, no COMPOSE */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+   /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
+    * settings will have no effect.
+    */
+   if (png_gamma_significant(png_ptr->screen_gamma) == 0)
+   {
+      png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+      png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+   }
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   /* Make sure the coefficients for the rgb to gray conversion are set
+    * appropriately.
+    */
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+      png_colorspace_set_rgb_coefficients(png_ptr);
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* Detect gray background and attempt to enable optimization for
+    * gray --> RGB case.
+    *
+    * Note:  if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+    * RGB_ALPHA (in which case need_expand is superfluous anyway), the
+    * background color might actually be gray yet not be flagged as such.
+    * This is not a problem for the current code, which uses
+    * PNG_BACKGROUND_IS_GRAY only to decide when to do the
+    * png_do_gray_to_rgb() transformation.
+    *
+    * TODO: this code needs to be revised to avoid the complexity and
+    * interdependencies.  The color type of the background should be recorded in
+    * png_set_background, along with the bit depth, then the code has a record
+    * of exactly what color space the background is currently in.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0)
+   {
+      /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
+       * the file was grayscale the background value is gray.
+       */
+      if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+         png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+   }
+
+   else if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+   {
+      /* PNG_COMPOSE: png_set_background was called with need_expand false,
+       * so the color is in the color space of the output or png_set_alpha_mode
+       * was called and the color is black.  Ignore RGB_TO_GRAY because that
+       * happens before GRAY_TO_RGB.
+       */
+      if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
+      {
+         if (png_ptr->background.red == png_ptr->background.green &&
+             png_ptr->background.red == png_ptr->background.blue)
+         {
+            png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+            png_ptr->background.gray = png_ptr->background.red;
+         }
+      }
+   }
+#endif /* READ_EXPAND && READ_BACKGROUND */
+#endif /* READ_GRAY_TO_RGB */
+
+   /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
+    * can be performed directly on the palette, and some (such as rgb to gray)
+    * can be optimized inside the palette.  This is particularly true of the
+    * composite (background and alpha) stuff, which can be pretty much all done
+    * in the palette even if the result is expanded to RGB or gray afterward.
+    *
+    * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
+    * earlier and the palette stuff is actually handled on the first row.  This
+    * leads to the reported bug that the palette returned by png_get_PLTE is not
+    * updated.
+    */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      png_init_palette_transformations(png_ptr);
+
+   else
+      png_init_rgb_transformations(png_ptr);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+   defined(PNG_READ_EXPAND_16_SUPPORTED)
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+       png_ptr->bit_depth != 16)
+   {
+      /* TODO: fix this.  Because the expand_16 operation is after the compose
+       * handling the background color must be 8, not 16, bits deep, but the
+       * application will supply a 16-bit value so reduce it here.
+       *
+       * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
+       * present, so that case is ok (until do_expand_16 is moved.)
+       *
+       * NOTE: this discards the low 16 bits of the user supplied background
+       * color, but until expand_16 works properly there is no choice!
+       */
+#     define CHOP(x) (x)=((png_uint_16)PNG_DIV257(x))
+      CHOP(png_ptr->background.red);
+      CHOP(png_ptr->background.green);
+      CHOP(png_ptr->background.blue);
+      CHOP(png_ptr->background.gray);
+#     undef CHOP
+   }
+#endif /* READ_BACKGROUND && READ_EXPAND_16 */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+   (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
+   defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
+   if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+       png_ptr->bit_depth == 16)
+   {
+      /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
+       * component this will also happen after PNG_COMPOSE and so the background
+       * color must be pre-expanded here.
+       *
+       * TODO: fix this too.
+       */
+      png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
+      png_ptr->background.green =
+         (png_uint_16)(png_ptr->background.green * 257);
+      png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
+      png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
+   }
+#endif
+
+   /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
+    * background support (see the comments in scripts/pnglibconf.dfa), this
+    * allows pre-multiplication of the alpha channel to be implemented as
+    * compositing on black.  This is probably sub-optimal and has been done in
+    * 1.5.4 betas simply to enable external critique and testing (i.e. to
+    * implement the new API quickly, without lots of internal changes.)
+    */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+#  ifdef PNG_READ_BACKGROUND_SUPPORTED
+      /* Includes ALPHA_MODE */
+      png_ptr->background_1 = png_ptr->background;
+#  endif
+
+   /* This needs to change - in the palette image case a whole set of tables are
+    * built when it would be quicker to just calculate the correct value for
+    * each palette entry directly.  Also, the test is too tricky - why check
+    * PNG_RGB_TO_GRAY if PNG_GAMMA is not set?  The answer seems to be that
+    * PNG_GAMMA is cancelled even if the gamma is known?  The test excludes the
+    * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
+    * the gamma tables will not be built even if composition is required on a
+    * gamma encoded value.
+    *
+    * In 1.5.4 this is addressed below by an additional check on the individual
+    * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
+    * tables.
+    */
+   if ((png_ptr->transformations & PNG_GAMMA) != 0 ||
+       ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 &&
+        (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+         png_gamma_significant(png_ptr->screen_gamma) != 0)) ||
+        ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+         (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+          png_gamma_significant(png_ptr->screen_gamma) != 0
+#  ifdef PNG_READ_BACKGROUND_SUPPORTED
+         || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE &&
+           png_gamma_significant(png_ptr->background_gamma) != 0)
+#  endif
+        )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+       png_gamma_significant(png_ptr->screen_gamma) != 0))
+   {
+      png_build_gamma_table(png_ptr, png_ptr->bit_depth);
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+      if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+      {
+         /* Issue a warning about this combination: because RGB_TO_GRAY is
+          * optimized to do the gamma transform if present yet do_background has
+          * to do the same thing if both options are set a
+          * double-gamma-correction happens.  This is true in all versions of
+          * libpng to date.
+          */
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+            png_warning(png_ptr,
+                "libpng does not support gamma+background+rgb_to_gray");
+
+         if ((png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) != 0)
+         {
+            /* We don't get to here unless there is a tRNS chunk with non-opaque
+             * entries - see the checking code at the start of this function.
+             */
+            png_color back, back_1;
+            png_colorp palette = png_ptr->palette;
+            int num_palette = png_ptr->num_palette;
+            int i;
+            if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
+            {
+
+               back.red = png_ptr->gamma_table[png_ptr->background.red];
+               back.green = png_ptr->gamma_table[png_ptr->background.green];
+               back.blue = png_ptr->gamma_table[png_ptr->background.blue];
+
+               back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
+               back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
+               back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
+            }
+            else
+            {
+               png_fixed_point g, gs;
+
+               switch (png_ptr->background_gamma_type)
+               {
+                  case PNG_BACKGROUND_GAMMA_SCREEN:
+                     g = (png_ptr->screen_gamma);
+                     gs = PNG_FP_1;
+                     break;
+
+                  case PNG_BACKGROUND_GAMMA_FILE:
+                     g = png_reciprocal(png_ptr->colorspace.gamma);
+                     gs = png_reciprocal2(png_ptr->colorspace.gamma,
+                         png_ptr->screen_gamma);
+                     break;
+
+                  case PNG_BACKGROUND_GAMMA_UNIQUE:
+                     g = png_reciprocal(png_ptr->background_gamma);
+                     gs = png_reciprocal2(png_ptr->background_gamma,
+                         png_ptr->screen_gamma);
+                     break;
+                  default:
+                     g = PNG_FP_1;    /* back_1 */
+                     gs = PNG_FP_1;   /* back */
+                     break;
+               }
+
+               if (png_gamma_significant(gs) != 0)
+               {
+                  back.red = png_gamma_8bit_correct(png_ptr->background.red,
+                      gs);
+                  back.green = png_gamma_8bit_correct(png_ptr->background.green,
+                      gs);
+                  back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+                      gs);
+               }
+
+               else
+               {
+                  back.red   = (png_byte)png_ptr->background.red;
+                  back.green = (png_byte)png_ptr->background.green;
+                  back.blue  = (png_byte)png_ptr->background.blue;
+               }
+
+               if (png_gamma_significant(g) != 0)
+               {
+                  back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
+                      g);
+                  back_1.green = png_gamma_8bit_correct(
+                      png_ptr->background.green, g);
+                  back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+                      g);
+               }
+
+               else
+               {
+                  back_1.red   = (png_byte)png_ptr->background.red;
+                  back_1.green = (png_byte)png_ptr->background.green;
+                  back_1.blue  = (png_byte)png_ptr->background.blue;
+               }
+            }
+
+            for (i = 0; i < num_palette; i++)
+            {
+               if (i < (int)png_ptr->num_trans &&
+                   png_ptr->trans_alpha[i] != 0xff)
+               {
+                  if (png_ptr->trans_alpha[i] == 0)
+                  {
+                     palette[i] = back;
+                  }
+                  else /* if (png_ptr->trans_alpha[i] != 0xff) */
+                  {
+                     png_byte v, w;
+
+                     v = png_ptr->gamma_to_1[palette[i].red];
+                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.red);
+                     palette[i].red = png_ptr->gamma_from_1[w];
+
+                     v = png_ptr->gamma_to_1[palette[i].green];
+                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.green);
+                     palette[i].green = png_ptr->gamma_from_1[w];
+
+                     v = png_ptr->gamma_to_1[palette[i].blue];
+                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue);
+                     palette[i].blue = png_ptr->gamma_from_1[w];
+                  }
+               }
+               else
+               {
+                  palette[i].red = png_ptr->gamma_table[palette[i].red];
+                  palette[i].green = png_ptr->gamma_table[palette[i].green];
+                  palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+               }
+            }
+
+            /* Prevent the transformations being done again.
+             *
+             * NOTE: this is highly dubious; it removes the transformations in
+             * place.  This seems inconsistent with the general treatment of the
+             * transformations elsewhere.
+             */
+            png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
+         } /* color_type == PNG_COLOR_TYPE_PALETTE */
+
+         /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
+         else /* color_type != PNG_COLOR_TYPE_PALETTE */
+         {
+            int gs_sig, g_sig;
+            png_fixed_point g = PNG_FP_1;  /* Correction to linear */
+            png_fixed_point gs = PNG_FP_1; /* Correction to screen */
+
+            switch (png_ptr->background_gamma_type)
+            {
+               case PNG_BACKGROUND_GAMMA_SCREEN:
+                  g = png_ptr->screen_gamma;
+                  /* gs = PNG_FP_1; */
+                  break;
+
+               case PNG_BACKGROUND_GAMMA_FILE:
+                  g = png_reciprocal(png_ptr->colorspace.gamma);
+                  gs = png_reciprocal2(png_ptr->colorspace.gamma,
+                      png_ptr->screen_gamma);
+                  break;
+
+               case PNG_BACKGROUND_GAMMA_UNIQUE:
+                  g = png_reciprocal(png_ptr->background_gamma);
+                  gs = png_reciprocal2(png_ptr->background_gamma,
+                      png_ptr->screen_gamma);
+                  break;
+
+               default:
+                  png_error(png_ptr, "invalid background gamma type");
+            }
+
+            g_sig = png_gamma_significant(g);
+            gs_sig = png_gamma_significant(gs);
+
+            if (g_sig != 0)
+               png_ptr->background_1.gray = png_gamma_correct(png_ptr,
+                   png_ptr->background.gray, g);
+
+            if (gs_sig != 0)
+               png_ptr->background.gray = png_gamma_correct(png_ptr,
+                   png_ptr->background.gray, gs);
+
+            if ((png_ptr->background.red != png_ptr->background.green) ||
+                (png_ptr->background.red != png_ptr->background.blue) ||
+                (png_ptr->background.red != png_ptr->background.gray))
+            {
+               /* RGB or RGBA with color background */
+               if (g_sig != 0)
+               {
+                  png_ptr->background_1.red = png_gamma_correct(png_ptr,
+                      png_ptr->background.red, g);
+
+                  png_ptr->background_1.green = png_gamma_correct(png_ptr,
+                      png_ptr->background.green, g);
+
+                  png_ptr->background_1.blue = png_gamma_correct(png_ptr,
+                      png_ptr->background.blue, g);
+               }
+
+               if (gs_sig != 0)
+               {
+                  png_ptr->background.red = png_gamma_correct(png_ptr,
+                      png_ptr->background.red, gs);
+
+                  png_ptr->background.green = png_gamma_correct(png_ptr,
+                      png_ptr->background.green, gs);
+
+                  png_ptr->background.blue = png_gamma_correct(png_ptr,
+                      png_ptr->background.blue, gs);
+               }
+            }
+
+            else
+            {
+               /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
+               png_ptr->background_1.red = png_ptr->background_1.green
+                   = png_ptr->background_1.blue = png_ptr->background_1.gray;
+
+               png_ptr->background.red = png_ptr->background.green
+                   = png_ptr->background.blue = png_ptr->background.gray;
+            }
+
+            /* The background is now in screen gamma: */
+            png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
+         } /* color_type != PNG_COLOR_TYPE_PALETTE */
+      }/* png_ptr->transformations & PNG_BACKGROUND */
+
+      else
+      /* Transformation does not include PNG_BACKGROUND */
+#endif /* READ_BACKGROUND */
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+         /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
+         && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
+         (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+#endif
+         )
+      {
+         png_colorp palette = png_ptr->palette;
+         int num_palette = png_ptr->num_palette;
+         int i;
+
+         /* NOTE: there are other transformations that should probably be in
+          * here too.
+          */
+         for (i = 0; i < num_palette; i++)
+         {
+            palette[i].red = png_ptr->gamma_table[palette[i].red];
+            palette[i].green = png_ptr->gamma_table[palette[i].green];
+            palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+         }
+
+         /* Done the gamma correction. */
+         png_ptr->transformations &= ~PNG_GAMMA;
+      } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
+   }
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+   else
+#endif
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+   /* No GAMMA transformation (see the hanging else 4 lines above) */
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
+   {
+      int i;
+      int istop = (int)png_ptr->num_trans;
+      png_color back;
+      png_colorp palette = png_ptr->palette;
+
+      back.red   = (png_byte)png_ptr->background.red;
+      back.green = (png_byte)png_ptr->background.green;
+      back.blue  = (png_byte)png_ptr->background.blue;
+
+      for (i = 0; i < istop; i++)
+      {
+         if (png_ptr->trans_alpha[i] == 0)
+         {
+            palette[i] = back;
+         }
+
+         else if (png_ptr->trans_alpha[i] != 0xff)
+         {
+            /* The png_composite() macro is defined in png.h */
+            png_composite(palette[i].red, palette[i].red,
+                png_ptr->trans_alpha[i], back.red);
+
+            png_composite(palette[i].green, palette[i].green,
+                png_ptr->trans_alpha[i], back.green);
+
+            png_composite(palette[i].blue, palette[i].blue,
+                png_ptr->trans_alpha[i], back.blue);
+         }
+      }
+
+      png_ptr->transformations &= ~PNG_COMPOSE;
+   }
+#endif /* READ_BACKGROUND */
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SHIFT) != 0 &&
+       (png_ptr->transformations & PNG_EXPAND) == 0 &&
+       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
+   {
+      int i;
+      int istop = png_ptr->num_palette;
+      int shift = 8 - png_ptr->sig_bit.red;
+
+      png_ptr->transformations &= ~PNG_SHIFT;
+
+      /* significant bits can be in the range 1 to 7 for a meaningful result, if
+       * the number of significant bits is 0 then no shift is done (this is an
+       * error condition which is silently ignored.)
+       */
+      if (shift > 0 && shift < 8)
+         for (i=0; i<istop; ++i)
+         {
+            int component = png_ptr->palette[i].red;
+
+            component >>= shift;
+            png_ptr->palette[i].red = (png_byte)component;
+         }
+
+      shift = 8 - png_ptr->sig_bit.green;
+      if (shift > 0 && shift < 8)
+         for (i=0; i<istop; ++i)
+         {
+            int component = png_ptr->palette[i].green;
+
+            component >>= shift;
+            png_ptr->palette[i].green = (png_byte)component;
+         }
+
+      shift = 8 - png_ptr->sig_bit.blue;
+      if (shift > 0 && shift < 8)
+         for (i=0; i<istop; ++i)
+         {
+            int component = png_ptr->palette[i].blue;
+
+            component >>= shift;
+            png_ptr->palette[i].blue = (png_byte)component;
+         }
+   }
+#endif /* READ_SHIFT */
+}
+
+/* Modify the info structure to reflect the transformations.  The
+ * info should be updated so a PNG file could be written with it,
+ * assuming the transformations result in valid PNG data.
+ */
+void /* PRIVATE */
+png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+   png_debug(1, "in png_read_transform_info");
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
+   {
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         /* This check must match what actually happens in
+          * png_do_expand_palette; if it ever checks the tRNS chunk to see if
+          * it is all opaque we must do the same (at present it does not.)
+          */
+         if (png_ptr->num_trans > 0)
+            info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+
+         else
+            info_ptr->color_type = PNG_COLOR_TYPE_RGB;
+
+         info_ptr->bit_depth = 8;
+         info_ptr->num_trans = 0;
+
+         if (png_ptr->palette == NULL)
+            png_error (png_ptr, "Palette is NULL in indexed image");
+      }
+      else
+      {
+         if (png_ptr->num_trans != 0)
+         {
+            if ((png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
+               info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+         }
+         if (info_ptr->bit_depth < 8)
+            info_ptr->bit_depth = 8;
+
+         info_ptr->num_trans = 0;
+      }
+   }
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+   /* The following is almost certainly wrong unless the background value is in
+    * the screen space!
+    */
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+      info_ptr->background = png_ptr->background;
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
+    * however it seems that the code in png_init_read_transformations, which has
+    * been called before this from png_read_update_info->png_read_start_row
+    * sometimes does the gamma transform and cancels the flag.
+    *
+    * TODO: this looks wrong; the info_ptr should end up with a gamma equal to
+    * the screen_gamma value.  The following probably results in weirdness if
+    * the info_ptr is used by the app after the rows have been read.
+    */
+   info_ptr->colorspace.gamma = png_ptr->colorspace.gamma;
+#endif
+
+   if (info_ptr->bit_depth == 16)
+   {
+#  ifdef PNG_READ_16BIT_SUPPORTED
+#     ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+         if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
+            info_ptr->bit_depth = 8;
+#     endif
+
+#     ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+         if ((png_ptr->transformations & PNG_16_TO_8) != 0)
+            info_ptr->bit_depth = 8;
+#     endif
+
+#  else
+      /* No 16-bit support: force chopping 16-bit input down to 8, in this case
+       * the app program can chose if both APIs are available by setting the
+       * correct scaling to use.
+       */
+#     ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+         /* For compatibility with previous versions use the strip method by
+          * default.  This code works because if PNG_SCALE_16_TO_8 is already
+          * set the code below will do that in preference to the chop.
+          */
+         png_ptr->transformations |= PNG_16_TO_8;
+         info_ptr->bit_depth = 8;
+#     else
+
+#        ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+            png_ptr->transformations |= PNG_SCALE_16_TO_8;
+            info_ptr->bit_depth = 8;
+#        else
+
+            CONFIGURATION ERROR: you must enable at least one 16 to 8 method
+#        endif
+#    endif
+#endif /* !READ_16BIT */
+   }
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
+      info_ptr->color_type = (png_byte)(info_ptr->color_type |
+         PNG_COLOR_MASK_COLOR);
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+      info_ptr->color_type = (png_byte)(info_ptr->color_type &
+         ~PNG_COLOR_MASK_COLOR);
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
+   {
+      if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
+          (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
+          png_ptr->palette_lookup != 0 && info_ptr->bit_depth == 8)
+      {
+         info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
+      }
+   }
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+       info_ptr->bit_depth == 8 &&
+       info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      info_ptr->bit_depth = 16;
+   }
+#endif
+
+#ifdef PNG_READ_PACK_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACK) != 0 &&
+       (info_ptr->bit_depth < 8))
+      info_ptr->bit_depth = 8;
+#endif
+
+   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      info_ptr->channels = 1;
+
+   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      info_ptr->channels = 3;
+
+   else
+      info_ptr->channels = 1;
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0)
+   {
+      info_ptr->color_type = (png_byte)(info_ptr->color_type &
+         ~PNG_COLOR_MASK_ALPHA);
+      info_ptr->num_trans = 0;
+   }
+#endif
+
+   if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      info_ptr->channels++;
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+   /* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */
+   if ((png_ptr->transformations & PNG_FILLER) != 0 &&
+       (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+       info_ptr->color_type == PNG_COLOR_TYPE_GRAY))
+   {
+      info_ptr->channels++;
+      /* If adding a true alpha channel not just filler */
+      if ((png_ptr->transformations & PNG_ADD_ALPHA) != 0)
+         info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+   }
+#endif
+
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
+defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+   {
+      if (png_ptr->user_transform_depth != 0)
+         info_ptr->bit_depth = png_ptr->user_transform_depth;
+
+      if (png_ptr->user_transform_channels != 0)
+         info_ptr->channels = png_ptr->user_transform_channels;
+   }
+#endif
+
+   info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
+       info_ptr->bit_depth);
+
+   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
+
+   /* Adding in 1.5.4: cache the above value in png_struct so that we can later
+    * check in png_rowbytes that the user buffer won't get overwritten.  Note
+    * that the field is not always set - if png_read_update_info isn't called
+    * the application has to either not do any transforms or get the calculation
+    * right itself.
+    */
+   png_ptr->info_rowbytes = info_ptr->rowbytes;
+
+#ifndef PNG_READ_EXPAND_SUPPORTED
+   if (png_ptr != NULL)
+      return;
+#endif
+}
+
+#ifdef PNG_READ_PACK_SUPPORTED
+/* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
+ * without changing the actual values.  Thus, if you had a row with
+ * a bit depth of 1, you would end up with bytes that only contained
+ * the numbers 0 or 1.  If you would rather they contain 0 and 255, use
+ * png_do_shift() after this.
+ */
+static void
+png_do_unpack(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_unpack");
+
+   if (row_info->bit_depth < 8)
+   {
+      png_uint_32 i;
+      png_uint_32 row_width=row_info->width;
+
+      switch (row_info->bit_depth)
+      {
+         case 1:
+         {
+            png_bytep sp = row + (size_t)((row_width - 1) >> 3);
+            png_bytep dp = row + (size_t)row_width - 1;
+            png_uint_32 shift = 7U - ((row_width + 7U) & 0x07);
+            for (i = 0; i < row_width; i++)
+            {
+               *dp = (png_byte)((*sp >> shift) & 0x01);
+
+               if (shift == 7)
+               {
+                  shift = 0;
+                  sp--;
+               }
+
+               else
+                  shift++;
+
+               dp--;
+            }
+            break;
+         }
+
+         case 2:
+         {
+
+            png_bytep sp = row + (size_t)((row_width - 1) >> 2);
+            png_bytep dp = row + (size_t)row_width - 1;
+            png_uint_32 shift = ((3U - ((row_width + 3U) & 0x03)) << 1);
+            for (i = 0; i < row_width; i++)
+            {
+               *dp = (png_byte)((*sp >> shift) & 0x03);
+
+               if (shift == 6)
+               {
+                  shift = 0;
+                  sp--;
+               }
+
+               else
+                  shift += 2;
+
+               dp--;
+            }
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp = row + (size_t)((row_width - 1) >> 1);
+            png_bytep dp = row + (size_t)row_width - 1;
+            png_uint_32 shift = ((1U - ((row_width + 1U) & 0x01)) << 2);
+            for (i = 0; i < row_width; i++)
+            {
+               *dp = (png_byte)((*sp >> shift) & 0x0f);
+
+               if (shift == 4)
+               {
+                  shift = 0;
+                  sp--;
+               }
+
+               else
+                  shift = 4;
+
+               dp--;
+            }
+            break;
+         }
+
+         default:
+            break;
+      }
+      row_info->bit_depth = 8;
+      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->rowbytes = row_width * row_info->channels;
+   }
+}
+#endif
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+/* Reverse the effects of png_do_shift.  This routine merely shifts the
+ * pixels back to their significant bits values.  Thus, if you have
+ * a row of bit depth 8, but only 5 are significant, this will shift
+ * the values back to 0 through 31.
+ */
+static void
+png_do_unshift(png_row_infop row_info, png_bytep row,
+    png_const_color_8p sig_bits)
+{
+   int color_type;
+
+   png_debug(1, "in png_do_unshift");
+
+   /* The palette case has already been handled in the _init routine. */
+   color_type = row_info->color_type;
+
+   if (color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      int shift[4];
+      int channels = 0;
+      int bit_depth = row_info->bit_depth;
+
+      if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+      {
+         shift[channels++] = bit_depth - sig_bits->red;
+         shift[channels++] = bit_depth - sig_bits->green;
+         shift[channels++] = bit_depth - sig_bits->blue;
+      }
+
+      else
+      {
+         shift[channels++] = bit_depth - sig_bits->gray;
+      }
+
+      if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      {
+         shift[channels++] = bit_depth - sig_bits->alpha;
+      }
+
+      {
+         int c, have_shift;
+
+         for (c = have_shift = 0; c < channels; ++c)
+         {
+            /* A shift of more than the bit depth is an error condition but it
+             * gets ignored here.
+             */
+            if (shift[c] <= 0 || shift[c] >= bit_depth)
+               shift[c] = 0;
+
+            else
+               have_shift = 1;
+         }
+
+         if (have_shift == 0)
+            return;
+      }
+
+      switch (bit_depth)
+      {
+         default:
+         /* Must be 1bpp gray: should not be here! */
+            /* NOTREACHED */
+            break;
+
+         case 2:
+         /* Must be 2bpp gray */
+         /* assert(channels == 1 && shift[0] == 1) */
+         {
+            png_bytep bp = row;
+            png_bytep bp_end = bp + row_info->rowbytes;
+
+            while (bp < bp_end)
+            {
+               int b = (*bp >> 1) & 0x55;
+               *bp++ = (png_byte)b;
+            }
+            break;
+         }
+
+         case 4:
+         /* Must be 4bpp gray */
+         /* assert(channels == 1) */
+         {
+            png_bytep bp = row;
+            png_bytep bp_end = bp + row_info->rowbytes;
+            int gray_shift = shift[0];
+            int mask =  0xf >> gray_shift;
+
+            mask |= mask << 4;
+
+            while (bp < bp_end)
+            {
+               int b = (*bp >> gray_shift) & mask;
+               *bp++ = (png_byte)b;
+            }
+            break;
+         }
+
+         case 8:
+         /* Single byte components, G, GA, RGB, RGBA */
+         {
+            png_bytep bp = row;
+            png_bytep bp_end = bp + row_info->rowbytes;
+            int channel = 0;
+
+            while (bp < bp_end)
+            {
+               int b = *bp >> shift[channel];
+               if (++channel >= channels)
+                  channel = 0;
+               *bp++ = (png_byte)b;
+            }
+            break;
+         }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+         case 16:
+         /* Double byte components, G, GA, RGB, RGBA */
+         {
+            png_bytep bp = row;
+            png_bytep bp_end = bp + row_info->rowbytes;
+            int channel = 0;
+
+            while (bp < bp_end)
+            {
+               int value = (bp[0] << 8) + bp[1];
+
+               value >>= shift[channel];
+               if (++channel >= channels)
+                  channel = 0;
+               *bp++ = (png_byte)(value >> 8);
+               *bp++ = (png_byte)value;
+            }
+            break;
+         }
+#endif
+      }
+   }
+}
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+/* Scale rows of bit depth 16 down to 8 accurately */
+static void
+png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_scale_16_to_8");
+
+   if (row_info->bit_depth == 16)
+   {
+      png_bytep sp = row; /* source */
+      png_bytep dp = row; /* destination */
+      png_bytep ep = sp + row_info->rowbytes; /* end+1 */
+
+      while (sp < ep)
+      {
+         /* The input is an array of 16-bit components, these must be scaled to
+          * 8 bits each.  For a 16-bit value V the required value (from the PNG
+          * specification) is:
+          *
+          *    (V * 255) / 65535
+          *
+          * This reduces to round(V / 257), or floor((V + 128.5)/257)
+          *
+          * Represent V as the two byte value vhi.vlo.  Make a guess that the
+          * result is the top byte of V, vhi, then the correction to this value
+          * is:
+          *
+          *    error = floor(((V-vhi.vhi) + 128.5) / 257)
+          *          = floor(((vlo-vhi) + 128.5) / 257)
+          *
+          * This can be approximated using integer arithmetic (and a signed
+          * shift):
+          *
+          *    error = (vlo-vhi+128) >> 8;
+          *
+          * The approximate differs from the exact answer only when (vlo-vhi) is
+          * 128; it then gives a correction of +1 when the exact correction is
+          * 0.  This gives 128 errors.  The exact answer (correct for all 16-bit
+          * input values) is:
+          *
+          *    error = (vlo-vhi+128)*65535 >> 24;
+          *
+          * An alternative arithmetic calculation which also gives no errors is:
+          *
+          *    (V * 255 + 32895) >> 16
+          */
+
+         png_int_32 tmp = *sp++; /* must be signed! */
+         tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
+         *dp++ = (png_byte)tmp;
+      }
+
+      row_info->bit_depth = 8;
+      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->rowbytes = row_info->width * row_info->channels;
+   }
+}
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+static void
+/* Simply discard the low byte.  This was the default behavior prior
+ * to libpng-1.5.4.
+ */
+png_do_chop(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_chop");
+
+   if (row_info->bit_depth == 16)
+   {
+      png_bytep sp = row; /* source */
+      png_bytep dp = row; /* destination */
+      png_bytep ep = sp + row_info->rowbytes; /* end+1 */
+
+      while (sp < ep)
+      {
+         *dp++ = *sp;
+         sp += 2; /* skip low byte */
+      }
+
+      row_info->bit_depth = 8;
+      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->rowbytes = row_info->width * row_info->channels;
+   }
+}
+#endif
+
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+static void
+png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_uint_32 row_width = row_info->width;
+
+   png_debug(1, "in png_do_read_swap_alpha");
+
+   if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+   {
+      /* This converts from RGBA to ARGB */
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            save = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      /* This converts from RRGGBBAA to AARRGGBB */
+      else
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save[2];
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            save[0] = *(--sp);
+            save[1] = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save[0];
+            *(--dp) = save[1];
+         }
+      }
+#endif
+   }
+
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+   {
+      /* This converts from GA to AG */
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            save = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      /* This converts from GGAA to AAGG */
+      else
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save[2];
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            save[0] = *(--sp);
+            save[1] = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save[0];
+            *(--dp) = save[1];
+         }
+      }
+#endif
+   }
+}
+#endif
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+static void
+png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_uint_32 row_width;
+   png_debug(1, "in png_do_read_invert_alpha");
+
+   row_width = row_info->width;
+   if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         /* This inverts the alpha channel in RGBA */
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            *(--dp) = (png_byte)(255 - *(--sp));
+
+/*          This does nothing:
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            We can replace it with:
+*/
+            sp-=3;
+            dp=sp;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      /* This inverts the alpha channel in RRGGBBAA */
+      else
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = (png_byte)(255 - *(--sp));
+
+/*          This does nothing:
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            We can replace it with:
+*/
+            sp-=6;
+            dp=sp;
+         }
+      }
+#endif
+   }
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         /* This inverts the alpha channel in GA */
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = *(--sp);
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      else
+      {
+         /* This inverts the alpha channel in GGAA */
+         png_bytep sp  = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            *(--dp) = (png_byte)(255 - *(--sp));
+            *(--dp) = (png_byte)(255 - *(--sp));
+/*
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+*/
+            sp-=2;
+            dp=sp;
+         }
+      }
+#endif
+   }
+}
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+/* Add filler channel if we have RGB color */
+static void
+png_do_read_filler(png_row_infop row_info, png_bytep row,
+    png_uint_32 filler, png_uint_32 flags)
+{
+   png_uint_32 i;
+   png_uint_32 row_width = row_info->width;
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+   png_byte hi_filler = (png_byte)(filler>>8);
+#endif
+   png_byte lo_filler = (png_byte)filler;
+
+   png_debug(1, "in png_do_read_filler");
+
+   if (
+       row_info->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+         {
+            /* This changes the data from G to GX */
+            png_bytep sp = row + (size_t)row_width;
+            png_bytep dp =  sp + (size_t)row_width;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            row_info->channels = 2;
+            row_info->pixel_depth = 16;
+            row_info->rowbytes = row_width * 2;
+         }
+
+         else
+         {
+            /* This changes the data from G to XG */
+            png_bytep sp = row + (size_t)row_width;
+            png_bytep dp = sp  + (size_t)row_width;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+            }
+            row_info->channels = 2;
+            row_info->pixel_depth = 16;
+            row_info->rowbytes = row_width * 2;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      else if (row_info->bit_depth == 16)
+      {
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+         {
+            /* This changes the data from GG to GGXX */
+            png_bytep sp = row + (size_t)row_width * 2;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            *(--dp) = hi_filler;
+            row_info->channels = 2;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+
+         else
+         {
+            /* This changes the data from GG to XXGG */
+            png_bytep sp = row + (size_t)row_width * 2;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
+            }
+            row_info->channels = 2;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+      }
+#endif
+   } /* COLOR_TYPE == GRAY */
+   else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+         {
+            /* This changes the data from RGB to RGBX */
+            png_bytep sp = row + (size_t)row_width * 3;
+            png_bytep dp = sp  + (size_t)row_width;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            row_info->channels = 4;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+
+         else
+         {
+            /* This changes the data from RGB to XRGB */
+            png_bytep sp = row + (size_t)row_width * 3;
+            png_bytep dp = sp + (size_t)row_width;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+            }
+            row_info->channels = 4;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+      }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+      else if (row_info->bit_depth == 16)
+      {
+         if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+         {
+            /* This changes the data from RRGGBB to RRGGBBXX */
+            png_bytep sp = row + (size_t)row_width * 6;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            *(--dp) = hi_filler;
+            row_info->channels = 4;
+            row_info->pixel_depth = 64;
+            row_info->rowbytes = row_width * 8;
+         }
+
+         else
+         {
+            /* This changes the data from RRGGBB to XXRRGGBB */
+            png_bytep sp = row + (size_t)row_width * 6;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
+            }
+
+            row_info->channels = 4;
+            row_info->pixel_depth = 64;
+            row_info->rowbytes = row_width * 8;
+         }
+      }
+#endif
+   } /* COLOR_TYPE == RGB */
+}
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* Expand grayscale files to RGB, with or without alpha */
+static void
+png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
+{
+   png_uint_32 i;
+   png_uint_32 row_width = row_info->width;
+
+   png_debug(1, "in png_do_gray_to_rgb");
+
+   if (row_info->bit_depth >= 8 &&
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) == 0)
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This changes G to RGB */
+            png_bytep sp = row + (size_t)row_width - 1;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *sp;
+               *(dp--) = *sp;
+               *(dp--) = *(sp--);
+            }
+         }
+
+         else
+         {
+            /* This changes GG to RRGGBB */
+            png_bytep sp = row + (size_t)row_width * 2 - 1;
+            png_bytep dp = sp  + (size_t)row_width * 4;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);
+            }
+         }
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This changes GA to RGBA */
+            png_bytep sp = row + (size_t)row_width * 2 - 1;
+            png_bytep dp = sp  + (size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *(sp--);
+               *(dp--) = *sp;
+               *(dp--) = *sp;
+               *(dp--) = *(sp--);
+            }
+         }
+
+         else
+         {
+            /* This changes GGAA to RRGGBBAA */
+            png_bytep sp = row + (size_t)row_width * 4 - 1;
+            png_bytep dp = sp  + (size_t)row_width * 4;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);
+            }
+         }
+      }
+      row_info->channels = (png_byte)(row_info->channels + 2);
+      row_info->color_type |= PNG_COLOR_MASK_COLOR;
+      row_info->pixel_depth = (png_byte)(row_info->channels *
+          row_info->bit_depth);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+   }
+}
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* Reduce RGB files to grayscale, with or without alpha
+ * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
+ * <http://www.inforamp.net/~poynton/>  (THIS LINK IS DEAD June 2008 but
+ * versions dated 1998 through November 2002 have been archived at
+ * https://web.archive.org/web/20000816232553/www.inforamp.net/
+ * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
+ * Charles Poynton poynton at poynton.com
+ *
+ *     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+ *
+ *  which can be expressed with integers as
+ *
+ *     Y = (6969 * R + 23434 * G + 2365 * B)/32768
+ *
+ * Poynton's current link (as of January 2003 through July 2011):
+ * <http://www.poynton.com/notes/colour_and_gamma/>
+ * has changed the numbers slightly:
+ *
+ *     Y = 0.2126*R + 0.7152*G + 0.0722*B
+ *
+ *  which can be expressed with integers as
+ *
+ *     Y = (6966 * R + 23436 * G + 2366 * B)/32768
+ *
+ *  Historically, however, libpng uses numbers derived from the ITU-R Rec 709
+ *  end point chromaticities and the D65 white point.  Depending on the
+ *  precision used for the D65 white point this produces a variety of different
+ *  numbers, however if the four decimal place value used in ITU-R Rec 709 is
+ *  used (0.3127,0.3290) the Y calculation would be:
+ *
+ *     Y = (6968 * R + 23435 * G + 2366 * B)/32768
+ *
+ *  While this is correct the rounding results in an overflow for white, because
+ *  the sum of the rounded coefficients is 32769, not 32768.  Consequently
+ *  libpng uses, instead, the closest non-overflowing approximation:
+ *
+ *     Y = (6968 * R + 23434 * G + 2366 * B)/32768
+ *
+ *  Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
+ *  (including an sRGB chunk) then the chromaticities are used to calculate the
+ *  coefficients.  See the chunk handling in pngrutil.c for more information.
+ *
+ *  In all cases the calculation is to be done in a linear colorspace.  If no
+ *  gamma information is available to correct the encoding of the original RGB
+ *  values this results in an implicit assumption that the original PNG RGB
+ *  values were linear.
+ *
+ *  Other integer coefficients can be used via png_set_rgb_to_gray().  Because
+ *  the API takes just red and green coefficients the blue coefficient is
+ *  calculated to make the sum 32768.  This will result in different rounding
+ *  to that used above.
+ */
+static int
+png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
+{
+   int rgb_error = 0;
+
+   png_debug(1, "in png_do_rgb_to_gray");
+
+   if ((row_info->color_type & PNG_COLOR_MASK_PALETTE) == 0 &&
+       (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
+      png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
+      png_uint_32 bc = 32768 - rc - gc;
+      png_uint_32 row_width = row_info->width;
+      int have_alpha = (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
+
+      if (row_info->bit_depth == 8)
+      {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+         /* Notice that gamma to/from 1 are not necessarily inverses (if
+          * there is an overall gamma correction).  Prior to 1.5.5 this code
+          * checked the linearized values for equality; this doesn't match
+          * the documentation, the original values must be checked.
+          */
+         if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+         {
+            png_bytep sp = row;
+            png_bytep dp = row;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte red   = *(sp++);
+               png_byte green = *(sp++);
+               png_byte blue  = *(sp++);
+
+               if (red != green || red != blue)
+               {
+                  red = png_ptr->gamma_to_1[red];
+                  green = png_ptr->gamma_to_1[green];
+                  blue = png_ptr->gamma_to_1[blue];
+
+                  rgb_error |= 1;
+                  *(dp++) = png_ptr->gamma_from_1[
+                      (rc*red + gc*green + bc*blue + 16384)>>15];
+               }
+
+               else
+               {
+                  /* If there is no overall correction the table will not be
+                   * set.
+                   */
+                  if (png_ptr->gamma_table != NULL)
+                     red = png_ptr->gamma_table[red];
+
+                  *(dp++) = red;
+               }
+
+               if (have_alpha != 0)
+                  *(dp++) = *(sp++);
+            }
+         }
+         else
+#endif
+         {
+            png_bytep sp = row;
+            png_bytep dp = row;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte red   = *(sp++);
+               png_byte green = *(sp++);
+               png_byte blue  = *(sp++);
+
+               if (red != green || red != blue)
+               {
+                  rgb_error |= 1;
+                  /* NOTE: this is the historical approach which simply
+                   * truncates the results.
+                   */
+                  *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
+               }
+
+               else
+                  *(dp++) = red;
+
+               if (have_alpha != 0)
+                  *(dp++) = *(sp++);
+            }
+         }
+      }
+
+      else /* RGB bit_depth == 16 */
+      {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+         if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
+         {
+            png_bytep sp = row;
+            png_bytep dp = row;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_uint_16 red, green, blue, w;
+               png_byte hi,lo;
+
+               hi=*(sp)++; lo=*(sp)++; red   = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; blue  = (png_uint_16)((hi << 8) | (lo));
+
+               if (red == green && red == blue)
+               {
+                  if (png_ptr->gamma_16_table != NULL)
+                     w = png_ptr->gamma_16_table[(red & 0xff)
+                         >> png_ptr->gamma_shift][red >> 8];
+
+                  else
+                     w = red;
+               }
+
+               else
+               {
+                  png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red & 0xff)
+                      >> png_ptr->gamma_shift][red>>8];
+                  png_uint_16 green_1 =
+                      png_ptr->gamma_16_to_1[(green & 0xff) >>
+                      png_ptr->gamma_shift][green>>8];
+                  png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue & 0xff)
+                      >> png_ptr->gamma_shift][blue>>8];
+                  png_uint_16 gray16  = (png_uint_16)((rc*red_1 + gc*green_1
+                      + bc*blue_1 + 16384)>>15);
+                  w = png_ptr->gamma_16_from_1[(gray16 & 0xff) >>
+                      png_ptr->gamma_shift][gray16 >> 8];
+                  rgb_error |= 1;
+               }
+
+               *(dp++) = (png_byte)((w>>8) & 0xff);
+               *(dp++) = (png_byte)(w & 0xff);
+
+               if (have_alpha != 0)
+               {
+                  *(dp++) = *(sp++);
+                  *(dp++) = *(sp++);
+               }
+            }
+         }
+         else
+#endif
+         {
+            png_bytep sp = row;
+            png_bytep dp = row;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_uint_16 red, green, blue, gray16;
+               png_byte hi,lo;
+
+               hi=*(sp)++; lo=*(sp)++; red   = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; blue  = (png_uint_16)((hi << 8) | (lo));
+
+               if (red != green || red != blue)
+                  rgb_error |= 1;
+
+               /* From 1.5.5 in the 16-bit case do the accurate conversion even
+                * in the 'fast' case - this is because this is where the code
+                * ends up when handling linear 16-bit data.
+                */
+               gray16  = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
+                  15);
+               *(dp++) = (png_byte)((gray16 >> 8) & 0xff);
+               *(dp++) = (png_byte)(gray16 & 0xff);
+
+               if (have_alpha != 0)
+               {
+                  *(dp++) = *(sp++);
+                  *(dp++) = *(sp++);
+               }
+            }
+         }
+      }
+
+      row_info->channels = (png_byte)(row_info->channels - 2);
+      row_info->color_type = (png_byte)(row_info->color_type &
+          ~PNG_COLOR_MASK_COLOR);
+      row_info->pixel_depth = (png_byte)(row_info->channels *
+          row_info->bit_depth);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+   }
+   return rgb_error;
+}
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+/* Replace any alpha or transparency with the supplied background color.
+ * "background" is already in the screen gamma, while "background_1" is
+ * at a gamma of 1.0.  Paletted files have already been taken care of.
+ */
+static void
+png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
+{
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   png_const_bytep gamma_table = png_ptr->gamma_table;
+   png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
+   png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
+   png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
+   png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
+   png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
+   int gamma_shift = png_ptr->gamma_shift;
+   int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
+#endif
+
+   png_bytep sp;
+   png_uint_32 i;
+   png_uint_32 row_width = row_info->width;
+   int shift;
+
+   png_debug(1, "in png_do_compose");
+
+   switch (row_info->color_type)
+   {
+      case PNG_COLOR_TYPE_GRAY:
+      {
+         switch (row_info->bit_depth)
+         {
+            case 1:
+            {
+               sp = row;
+               shift = 7;
+               for (i = 0; i < row_width; i++)
+               {
+                  if ((png_uint_16)((*sp >> shift) & 0x01)
+                     == png_ptr->trans_color.gray)
+                  {
+                     unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
+                     tmp |=
+                         (unsigned int)(png_ptr->background.gray << shift);
+                     *sp = (png_byte)(tmp & 0xff);
+                  }
+
+                  if (shift == 0)
+                  {
+                     shift = 7;
+                     sp++;
+                  }
+
+                  else
+                     shift--;
+               }
+               break;
+            }
+
+            case 2:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_table != NULL)
+               {
+                  sp = row;
+                  shift = 6;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x03)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+                        tmp |=
+                           (unsigned int)png_ptr->background.gray << shift;
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     else
+                     {
+                        unsigned int p = (*sp >> shift) & 0x03;
+                        unsigned int g = (gamma_table [p | (p << 2) |
+                            (p << 4) | (p << 6)] >> 6) & 0x03;
+                        unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+                        tmp |= (unsigned int)(g << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 6;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 2;
+                  }
+               }
+
+               else
+#endif
+               {
+                  sp = row;
+                  shift = 6;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x03)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+                        tmp |=
+                            (unsigned int)png_ptr->background.gray << shift;
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 6;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 2;
+                  }
+               }
+               break;
+            }
+
+            case 4:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_table != NULL)
+               {
+                  sp = row;
+                  shift = 4;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x0f)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
+                        tmp |=
+                           (unsigned int)(png_ptr->background.gray << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     else
+                     {
+                        unsigned int p = (*sp >> shift) & 0x0f;
+                        unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
+                           0x0f;
+                        unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
+                        tmp |= (unsigned int)(g << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 4;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 4;
+                  }
+               }
+
+               else
+#endif
+               {
+                  sp = row;
+                  shift = 4;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x0f)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
+                        tmp |=
+                           (unsigned int)(png_ptr->background.gray << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 4;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 4;
+                  }
+               }
+               break;
+            }
+
+            case 8:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_table != NULL)
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp++)
+                  {
+                     if (*sp == png_ptr->trans_color.gray)
+                        *sp = (png_byte)png_ptr->background.gray;
+
+                     else
+                        *sp = gamma_table[*sp];
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp++)
+                  {
+                     if (*sp == png_ptr->trans_color.gray)
+                        *sp = (png_byte)png_ptr->background.gray;
+                  }
+               }
+               break;
+            }
+
+            case 16:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_16 != NULL)
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp += 2)
+                  {
+                     png_uint_16 v;
+
+                     v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                     if (v == png_ptr->trans_color.gray)
+                     {
+                        /* Background is already in screen gamma */
+                        *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                        *(sp + 1) = (png_byte)(png_ptr->background.gray
+                             & 0xff);
+                     }
+
+                     else
+                     {
+                        v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                        *sp = (png_byte)((v >> 8) & 0xff);
+                        *(sp + 1) = (png_byte)(v & 0xff);
+                     }
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp += 2)
+                  {
+                     png_uint_16 v;
+
+                     v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                     if (v == png_ptr->trans_color.gray)
+                     {
+                        *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                        *(sp + 1) = (png_byte)(png_ptr->background.gray
+                             & 0xff);
+                     }
+                  }
+               }
+               break;
+            }
+
+            default:
+               break;
+         }
+         break;
+      }
+
+      case PNG_COLOR_TYPE_RGB:
+      {
+         if (row_info->bit_depth == 8)
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_table != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 3)
+               {
+                  if (*sp == png_ptr->trans_color.red &&
+                      *(sp + 1) == png_ptr->trans_color.green &&
+                      *(sp + 2) == png_ptr->trans_color.blue)
+                  {
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+
+                  else
+                  {
+                     *sp = gamma_table[*sp];
+                     *(sp + 1) = gamma_table[*(sp + 1)];
+                     *(sp + 2) = gamma_table[*(sp + 2)];
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 3)
+               {
+                  if (*sp == png_ptr->trans_color.red &&
+                      *(sp + 1) == png_ptr->trans_color.green &&
+                      *(sp + 2) == png_ptr->trans_color.blue)
+                  {
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+               }
+            }
+         }
+         else /* if (row_info->bit_depth == 16) */
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_16 != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 6)
+               {
+                  png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                  png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                      + *(sp + 5));
+
+                  if (r == png_ptr->trans_color.red &&
+                      g == png_ptr->trans_color.green &&
+                      b == png_ptr->trans_color.blue)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+
+                  else
+                  {
+                     png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                     *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                     *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(v & 0xff);
+                  }
+               }
+            }
+
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 6)
+               {
+                  png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                  png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                      + *(sp + 5));
+
+                  if (r == png_ptr->trans_color.red &&
+                      g == png_ptr->trans_color.green &&
+                      b == png_ptr->trans_color.blue)
+                  {
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+               }
+            }
+         }
+         break;
+      }
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+      {
+         if (row_info->bit_depth == 8)
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+                gamma_table != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 2)
+               {
+                  png_uint_16 a = *(sp + 1);
+
+                  if (a == 0xff)
+                     *sp = gamma_table[*sp];
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)png_ptr->background.gray;
+                  }
+
+                  else
+                  {
+                     png_byte v, w;
+
+                     v = gamma_to_1[*sp];
+                     png_composite(w, v, a, png_ptr->background_1.gray);
+                     if (optimize == 0)
+                        w = gamma_from_1[w];
+                     *sp = w;
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 2)
+               {
+                  png_byte a = *(sp + 1);
+
+                  if (a == 0)
+                     *sp = (png_byte)png_ptr->background.gray;
+
+                  else if (a < 0xff)
+                     png_composite(*sp, *sp, a, png_ptr->background.gray);
+               }
+            }
+         }
+         else /* if (png_ptr->bit_depth == 16) */
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+                gamma_16_to_1 != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  if (a == (png_uint_16)0xffff)
+                  {
+                     png_uint_16 v;
+
+                     v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+                  }
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+                  }
+
+                  else
+                  {
+                     png_uint_16 g, v, w;
+
+                     g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+                     png_composite_16(v, g, a, png_ptr->background_1.gray);
+                     if (optimize != 0)
+                        w = v;
+                     else
+                        w = gamma_16_from_1[(v & 0xff) >>
+                            gamma_shift][v >> 8];
+                     *sp = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(w & 0xff);
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  if (a == 0)
+                  {
+                     *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+                  }
+
+                  else if (a < 0xffff)
+                  {
+                     png_uint_16 g, v;
+
+                     g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                     png_composite_16(v, g, a, png_ptr->background.gray);
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+                  }
+               }
+            }
+         }
+         break;
+      }
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+      {
+         if (row_info->bit_depth == 8)
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+                gamma_table != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_byte a = *(sp + 3);
+
+                  if (a == 0xff)
+                  {
+                     *sp = gamma_table[*sp];
+                     *(sp + 1) = gamma_table[*(sp + 1)];
+                     *(sp + 2) = gamma_table[*(sp + 2)];
+                  }
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+
+                  else
+                  {
+                     png_byte v, w;
+
+                     v = gamma_to_1[*sp];
+                     png_composite(w, v, a, png_ptr->background_1.red);
+                     if (optimize == 0) w = gamma_from_1[w];
+                     *sp = w;
+
+                     v = gamma_to_1[*(sp + 1)];
+                     png_composite(w, v, a, png_ptr->background_1.green);
+                     if (optimize == 0) w = gamma_from_1[w];
+                     *(sp + 1) = w;
+
+                     v = gamma_to_1[*(sp + 2)];
+                     png_composite(w, v, a, png_ptr->background_1.blue);
+                     if (optimize == 0) w = gamma_from_1[w];
+                     *(sp + 2) = w;
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_byte a = *(sp + 3);
+
+                  if (a == 0)
+                  {
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+
+                  else if (a < 0xff)
+                  {
+                     png_composite(*sp, *sp, a, png_ptr->background.red);
+
+                     png_composite(*(sp + 1), *(sp + 1), a,
+                         png_ptr->background.green);
+
+                     png_composite(*(sp + 2), *(sp + 2), a,
+                         png_ptr->background.blue);
+                  }
+               }
+            }
+         }
+         else /* if (row_info->bit_depth == 16) */
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+                gamma_16_to_1 != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 8)
+               {
+                  png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+                      << 8) + (png_uint_16)(*(sp + 7)));
+
+                  if (a == (png_uint_16)0xffff)
+                  {
+                     png_uint_16 v;
+
+                     v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                     *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                     *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(v & 0xff);
+                  }
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+
+                  else
+                  {
+                     png_uint_16 v, w;
+
+                     v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+                     png_composite_16(w, v, a, png_ptr->background_1.red);
+                     if (optimize == 0)
+                        w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                             8];
+                     *sp = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(w & 0xff);
+
+                     v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                     png_composite_16(w, v, a, png_ptr->background_1.green);
+                     if (optimize == 0)
+                        w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                             8];
+
+                     *(sp + 2) = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(w & 0xff);
+
+                     v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                     png_composite_16(w, v, a, png_ptr->background_1.blue);
+                     if (optimize == 0)
+                        w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                             8];
+
+                     *(sp + 4) = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(w & 0xff);
+                  }
+               }
+            }
+
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 8)
+               {
+                  png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+                      << 8) + (png_uint_16)(*(sp + 7)));
+
+                  if (a == 0)
+                  {
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+
+                  else if (a < 0xffff)
+                  {
+                     png_uint_16 v;
+
+                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                     png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                         + *(sp + 3));
+                     png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                         + *(sp + 5));
+
+                     png_composite_16(v, r, a, png_ptr->background.red);
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+
+                     png_composite_16(v, g, a, png_ptr->background.green);
+                     *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(v & 0xff);
+
+                     png_composite_16(v, b, a, png_ptr->background.blue);
+                     *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(v & 0xff);
+                  }
+               }
+            }
+         }
+         break;
+      }
+
+      default:
+         break;
+   }
+}
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Gamma correct the image, avoiding the alpha channel.  Make sure
+ * you do this after you deal with the transparency issue on grayscale
+ * or RGB images. If your bit depth is 8, use gamma_table, if it
+ * is 16, use gamma_16_table and gamma_shift.  Build these with
+ * build_gamma_table().
+ */
+static void
+png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
+{
+   png_const_bytep gamma_table = png_ptr->gamma_table;
+   png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
+   int gamma_shift = png_ptr->gamma_shift;
+
+   png_bytep sp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_gamma");
+
+   if (((row_info->bit_depth <= 8 && gamma_table != NULL) ||
+       (row_info->bit_depth == 16 && gamma_16_table != NULL)))
+   {
+      switch (row_info->color_type)
+      {
+         case PNG_COLOR_TYPE_RGB:
+         {
+            if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp++;
+                  *sp = gamma_table[*sp];
+                  sp++;
+                  *sp = gamma_table[*sp];
+                  sp++;
+               }
+            }
+
+            else /* if (row_info->bit_depth == 16) */
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+               }
+            }
+            break;
+         }
+
+         case PNG_COLOR_TYPE_RGB_ALPHA:
+         {
+            if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp++;
+
+                  *sp = gamma_table[*sp];
+                  sp++;
+
+                  *sp = gamma_table[*sp];
+                  sp++;
+
+                  sp++;
+               }
+            }
+
+            else /* if (row_info->bit_depth == 16) */
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 4;
+               }
+            }
+            break;
+         }
+
+         case PNG_COLOR_TYPE_GRAY_ALPHA:
+         {
+            if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp += 2;
+               }
+            }
+
+            else /* if (row_info->bit_depth == 16) */
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 4;
+               }
+            }
+            break;
+         }
+
+         case PNG_COLOR_TYPE_GRAY:
+         {
+            if (row_info->bit_depth == 2)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i += 4)
+               {
+                  int a = *sp & 0xc0;
+                  int b = *sp & 0x30;
+                  int c = *sp & 0x0c;
+                  int d = *sp & 0x03;
+
+                  *sp = (png_byte)(
+                      ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])   ) & 0xc0)|
+                      ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
+                      ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
+                      ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
+                  sp++;
+               }
+            }
+
+            if (row_info->bit_depth == 4)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i += 2)
+               {
+                  int msb = *sp & 0xf0;
+                  int lsb = *sp & 0x0f;
+
+                  *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
+                      | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
+                  sp++;
+               }
+            }
+
+            else if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp++;
+               }
+            }
+
+            else if (row_info->bit_depth == 16)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+               }
+            }
+            break;
+         }
+
+         default:
+            break;
+      }
+   }
+}
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* Encode the alpha channel to the output gamma (the input channel is always
+ * linear.)  Called only with color types that have an alpha channel.  Needs the
+ * from_1 tables.
+ */
+static void
+png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
+{
+   png_uint_32 row_width = row_info->width;
+
+   png_debug(1, "in png_do_encode_alpha");
+
+   if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep table = png_ptr->gamma_from_1;
+
+         if (table != NULL)
+         {
+            int step = (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
+
+            /* The alpha channel is the last component: */
+            row += step - 1;
+
+            for (; row_width > 0; --row_width, row += step)
+               *row = table[*row];
+
+            return;
+         }
+      }
+
+      else if (row_info->bit_depth == 16)
+      {
+         png_uint_16pp table = png_ptr->gamma_16_from_1;
+         int gamma_shift = png_ptr->gamma_shift;
+
+         if (table != NULL)
+         {
+            int step = (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
+
+            /* The alpha channel is the last component: */
+            row += step - 2;
+
+            for (; row_width > 0; --row_width, row += step)
+            {
+               png_uint_16 v;
+
+               v = table[*(row + 1) >> gamma_shift][*row];
+               *row = (png_byte)((v >> 8) & 0xff);
+               *(row + 1) = (png_byte)(v & 0xff);
+            }
+
+            return;
+         }
+      }
+   }
+
+   /* Only get to here if called with a weird row_info; no harm has been done,
+    * so just issue a warning.
+    */
+   png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
+}
+#endif
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expands a palette row to an RGB or RGBA row depending
+ * upon whether you supply trans and num_trans.
+ */
+static void
+png_do_expand_palette(png_structrp png_ptr, png_row_infop row_info,
+    png_bytep row, png_const_colorp palette, png_const_bytep trans_alpha,
+    int num_trans)
+{
+   int shift, value;
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_expand_palette");
+
+   if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (row_info->bit_depth < 8)
+      {
+         switch (row_info->bit_depth)
+         {
+            case 1:
+            {
+               sp = row + (size_t)((row_width - 1) >> 3);
+               dp = row + (size_t)row_width - 1;
+               shift = 7 - (int)((row_width + 7) & 0x07);
+               for (i = 0; i < row_width; i++)
+               {
+                  if ((*sp >> shift) & 0x01)
+                     *dp = 1;
+
+                  else
+                     *dp = 0;
+
+                  if (shift == 7)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift++;
+
+                  dp--;
+               }
+               break;
+            }
+
+            case 2:
+            {
+               sp = row + (size_t)((row_width - 1) >> 2);
+               dp = row + (size_t)row_width - 1;
+               shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x03;
+                  *dp = (png_byte)value;
+                  if (shift == 6)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift += 2;
+
+                  dp--;
+               }
+               break;
+            }
+
+            case 4:
+            {
+               sp = row + (size_t)((row_width - 1) >> 1);
+               dp = row + (size_t)row_width - 1;
+               shift = (int)((row_width & 0x01) << 2);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x0f;
+                  *dp = (png_byte)value;
+                  if (shift == 4)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift += 4;
+
+                  dp--;
+               }
+               break;
+            }
+
+            default:
+               break;
+         }
+         row_info->bit_depth = 8;
+         row_info->pixel_depth = 8;
+         row_info->rowbytes = row_width;
+      }
+
+      if (row_info->bit_depth == 8)
+      {
+         {
+            if (num_trans > 0)
+            {
+               sp = row + (size_t)row_width - 1;
+               dp = row + ((size_t)row_width << 2) - 1;
+
+               i = 0;
+#ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
+               if (png_ptr->riffled_palette != NULL)
+               {
+                  /* The RGBA optimization works with png_ptr->bit_depth == 8
+                   * but sometimes row_info->bit_depth has been changed to 8.
+                   * In these cases, the palette hasn't been riffled.
+                   */
+                  i = png_do_expand_palette_rgba8_neon(png_ptr, row_info, row,
+                      &sp, &dp);
+               }
+#else
+               PNG_UNUSED(png_ptr)
+#endif
+
+               for (; i < row_width; i++)
+               {
+                  if ((int)(*sp) >= num_trans)
+                     *dp-- = 0xff;
+                  else
+                     *dp-- = trans_alpha[*sp];
+                  *dp-- = palette[*sp].blue;
+                  *dp-- = palette[*sp].green;
+                  *dp-- = palette[*sp].red;
+                  sp--;
+               }
+               row_info->bit_depth = 8;
+               row_info->pixel_depth = 32;
+               row_info->rowbytes = row_width * 4;
+               row_info->color_type = 6;
+               row_info->channels = 4;
+            }
+
+            else
+            {
+               sp = row + (size_t)row_width - 1;
+               dp = row + (size_t)(row_width * 3) - 1;
+               i = 0;
+#ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
+               i = png_do_expand_palette_rgb8_neon(png_ptr, row_info, row,
+                   &sp, &dp);
+#else
+               PNG_UNUSED(png_ptr)
+#endif
+
+               for (; i < row_width; i++)
+               {
+                  *dp-- = palette[*sp].blue;
+                  *dp-- = palette[*sp].green;
+                  *dp-- = palette[*sp].red;
+                  sp--;
+               }
+
+               row_info->bit_depth = 8;
+               row_info->pixel_depth = 24;
+               row_info->rowbytes = row_width * 3;
+               row_info->color_type = 2;
+               row_info->channels = 3;
+            }
+         }
+      }
+   }
+}
+
+/* If the bit depth < 8, it is expanded to 8.  Also, if the already
+ * expanded transparency value is supplied, an alpha channel is built.
+ */
+static void
+png_do_expand(png_row_infop row_info, png_bytep row,
+    png_const_color_16p trans_color)
+{
+   int shift, value;
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_expand");
+
+   if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      unsigned int gray = trans_color != NULL ? trans_color->gray : 0;
+
+      if (row_info->bit_depth < 8)
+      {
+         switch (row_info->bit_depth)
+         {
+            case 1:
+            {
+               gray = (gray & 0x01) * 0xff;
+               sp = row + (size_t)((row_width - 1) >> 3);
+               dp = row + (size_t)row_width - 1;
+               shift = 7 - (int)((row_width + 7) & 0x07);
+               for (i = 0; i < row_width; i++)
+               {
+                  if ((*sp >> shift) & 0x01)
+                     *dp = 0xff;
+
+                  else
+                     *dp = 0;
+
+                  if (shift == 7)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift++;
+
+                  dp--;
+               }
+               break;
+            }
+
+            case 2:
+            {
+               gray = (gray & 0x03) * 0x55;
+               sp = row + (size_t)((row_width - 1) >> 2);
+               dp = row + (size_t)row_width - 1;
+               shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x03;
+                  *dp = (png_byte)(value | (value << 2) | (value << 4) |
+                     (value << 6));
+                  if (shift == 6)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift += 2;
+
+                  dp--;
+               }
+               break;
+            }
+
+            case 4:
+            {
+               gray = (gray & 0x0f) * 0x11;
+               sp = row + (size_t)((row_width - 1) >> 1);
+               dp = row + (size_t)row_width - 1;
+               shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x0f;
+                  *dp = (png_byte)(value | (value << 4));
+                  if (shift == 4)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift = 4;
+
+                  dp--;
+               }
+               break;
+            }
+
+            default:
+               break;
+         }
+
+         row_info->bit_depth = 8;
+         row_info->pixel_depth = 8;
+         row_info->rowbytes = row_width;
+      }
+
+      if (trans_color != NULL)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            gray = gray & 0xff;
+            sp = row + (size_t)row_width - 1;
+            dp = row + ((size_t)row_width << 1) - 1;
+
+            for (i = 0; i < row_width; i++)
+            {
+               if ((*sp & 0xffU) == gray)
+                  *dp-- = 0;
+
+               else
+                  *dp-- = 0xff;
+
+               *dp-- = *sp--;
+            }
+         }
+
+         else if (row_info->bit_depth == 16)
+         {
+            unsigned int gray_high = (gray >> 8) & 0xff;
+            unsigned int gray_low = gray & 0xff;
+            sp = row + row_info->rowbytes - 1;
+            dp = row + (row_info->rowbytes << 1) - 1;
+            for (i = 0; i < row_width; i++)
+            {
+               if ((*(sp - 1) & 0xffU) == gray_high &&
+                   (*(sp) & 0xffU) == gray_low)
+               {
+                  *dp-- = 0;
+                  *dp-- = 0;
+               }
+
+               else
+               {
+                  *dp-- = 0xff;
+                  *dp-- = 0xff;
+               }
+
+               *dp-- = *sp--;
+               *dp-- = *sp--;
+            }
+         }
+
+         row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+         row_info->channels = 2;
+         row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+             row_width);
+      }
+   }
+   else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
+       trans_color != NULL)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         png_byte red = (png_byte)(trans_color->red & 0xff);
+         png_byte green = (png_byte)(trans_color->green & 0xff);
+         png_byte blue = (png_byte)(trans_color->blue & 0xff);
+         sp = row + (size_t)row_info->rowbytes - 1;
+         dp = row + ((size_t)row_width << 2) - 1;
+         for (i = 0; i < row_width; i++)
+         {
+            if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
+               *dp-- = 0;
+
+            else
+               *dp-- = 0xff;
+
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+         }
+      }
+      else if (row_info->bit_depth == 16)
+      {
+         png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
+         png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
+         png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
+         png_byte red_low = (png_byte)(trans_color->red & 0xff);
+         png_byte green_low = (png_byte)(trans_color->green & 0xff);
+         png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
+         sp = row + row_info->rowbytes - 1;
+         dp = row + ((size_t)row_width << 3) - 1;
+         for (i = 0; i < row_width; i++)
+         {
+            if (*(sp - 5) == red_high &&
+                *(sp - 4) == red_low &&
+                *(sp - 3) == green_high &&
+                *(sp - 2) == green_low &&
+                *(sp - 1) == blue_high &&
+                *(sp    ) == blue_low)
+            {
+               *dp-- = 0;
+               *dp-- = 0;
+            }
+
+            else
+            {
+               *dp-- = 0xff;
+               *dp-- = 0xff;
+            }
+
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+         }
+      }
+      row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+      row_info->channels = 4;
+      row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+   }
+}
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* If the bit depth is 8 and the color type is not a palette type expand the
+ * whole row to 16 bits.  Has no effect otherwise.
+ */
+static void
+png_do_expand_16(png_row_infop row_info, png_bytep row)
+{
+   if (row_info->bit_depth == 8 &&
+      row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      /* The row have a sequence of bytes containing [0..255] and we need
+       * to turn it into another row containing [0..65535], to do this we
+       * calculate:
+       *
+       *  (input / 255) * 65535
+       *
+       *  Which happens to be exactly input * 257 and this can be achieved
+       *  simply by byte replication in place (copying backwards).
+       */
+      png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
+      png_byte *dp = sp + row_info->rowbytes;  /* destination, end + 1 */
+      while (dp > sp)
+      {
+         dp[-2] = dp[-1] = *--sp; dp -= 2;
+      }
+
+      row_info->rowbytes *= 2;
+      row_info->bit_depth = 16;
+      row_info->pixel_depth = (png_byte)(row_info->channels * 16);
+   }
+}
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+static void
+png_do_quantize(png_row_infop row_info, png_bytep row,
+    png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
+{
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_quantize");
+
+   if (row_info->bit_depth == 8)
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup)
+      {
+         int r, g, b, p;
+         sp = row;
+         dp = row;
+         for (i = 0; i < row_width; i++)
+         {
+            r = *sp++;
+            g = *sp++;
+            b = *sp++;
+
+            /* This looks real messy, but the compiler will reduce
+             * it down to a reasonable formula.  For example, with
+             * 5 bits per color, we get:
+             * p = (((r >> 3) & 0x1f) << 10) |
+             *    (((g >> 3) & 0x1f) << 5) |
+             *    ((b >> 3) & 0x1f);
+             */
+            p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
+                ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
+                (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
+                (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
+                ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
+                (PNG_QUANTIZE_BLUE_BITS)) |
+                ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
+                ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
+
+            *dp++ = palette_lookup[p];
+         }
+
+         row_info->color_type = PNG_COLOR_TYPE_PALETTE;
+         row_info->channels = 1;
+         row_info->pixel_depth = row_info->bit_depth;
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+         palette_lookup != NULL)
+      {
+         int r, g, b, p;
+         sp = row;
+         dp = row;
+         for (i = 0; i < row_width; i++)
+         {
+            r = *sp++;
+            g = *sp++;
+            b = *sp++;
+            sp++;
+
+            p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
+                ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
+                (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
+                (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
+                ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
+                (PNG_QUANTIZE_BLUE_BITS)) |
+                ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
+                ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
+
+            *dp++ = palette_lookup[p];
+         }
+
+         row_info->color_type = PNG_COLOR_TYPE_PALETTE;
+         row_info->channels = 1;
+         row_info->pixel_depth = row_info->bit_depth;
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+         quantize_lookup)
+      {
+         sp = row;
+
+         for (i = 0; i < row_width; i++, sp++)
+         {
+            *sp = quantize_lookup[*sp];
+         }
+      }
+   }
+}
+#endif /* READ_QUANTIZE */
+
+/* Transform the row.  The order of transformations is significant,
+ * and is very touchy.  If you add a transformation, take care to
+ * decide how it fits in with the other transformations here.
+ */
+void /* PRIVATE */
+png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
+{
+   png_debug(1, "in png_do_read_transformations");
+
+   if (png_ptr->row_buf == NULL)
+   {
+      /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
+       * error is incredibly rare and incredibly easy to debug without this
+       * information.
+       */
+      png_error(png_ptr, "NULL row buffer");
+   }
+
+   /* The following is debugging; prior to 1.5.4 the code was never compiled in;
+    * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
+    * PNG_WARN_UNINITIALIZED_ROW removed.  In 1.6 the new flag is set only for
+    * all transformations, however in practice the ROW_INIT always gets done on
+    * demand, if necessary.
+    */
+   if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
+       (png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+   {
+      /* Application has failed to call either png_read_start_image() or
+       * png_read_update_info() after setting transforms that expand pixels.
+       * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
+       */
+      png_error(png_ptr, "Uninitialized row");
+   }
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+#ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
+         if ((png_ptr->num_trans > 0) && (png_ptr->bit_depth == 8))
+         {
+            if (png_ptr->riffled_palette == NULL)
+            {
+               /* Initialize the accelerated palette expansion. */
+               png_ptr->riffled_palette =
+                   (png_bytep)png_malloc(png_ptr, 256 * 4);
+               png_riffle_palette_neon(png_ptr);
+            }
+         }
+#endif
+         png_do_expand_palette(png_ptr, row_info, png_ptr->row_buf + 1,
+             png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
+      }
+
+      else
+      {
+         if (png_ptr->num_trans != 0 &&
+             (png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
+            png_do_expand(row_info, png_ptr->row_buf + 1,
+                &(png_ptr->trans_color));
+
+         else
+            png_do_expand(row_info, png_ptr->row_buf + 1, NULL);
+      }
+   }
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) == 0 &&
+       (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+       row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+          0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+   {
+      int rgb_error =
+          png_do_rgb_to_gray(png_ptr, row_info,
+              png_ptr->row_buf + 1);
+
+      if (rgb_error != 0)
+      {
+         png_ptr->rgb_to_gray_status=1;
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_WARN)
+            png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_ERR)
+            png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+      }
+   }
+#endif
+
+/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
+ *
+ *   In most cases, the "simple transparency" should be done prior to doing
+ *   gray-to-RGB, or you will have to test 3x as many bytes to check if a
+ *   pixel is transparent.  You would also need to make sure that the
+ *   transparency information is upgraded to RGB.
+ *
+ *   To summarize, the current flow is:
+ *   - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
+ *                                   with background "in place" if transparent,
+ *                                   convert to RGB if necessary
+ *   - Gray + alpha -> composite with gray background and remove alpha bytes,
+ *                                   convert to RGB if necessary
+ *
+ *   To support RGB backgrounds for gray images we need:
+ *   - Gray + simple transparency -> convert to RGB + simple transparency,
+ *                                   compare 3 or 6 bytes and composite with
+ *                                   background "in place" if transparent
+ *                                   (3x compare/pixel compared to doing
+ *                                   composite with gray bkgrnd)
+ *   - Gray + alpha -> convert to RGB + alpha, composite with background and
+ *                                   remove alpha bytes (3x float
+ *                                   operations/pixel compared with composite
+ *                                   on gray background)
+ *
+ *  Greg's change will do this.  The reason it wasn't done before is for
+ *  performance, as this increases the per-pixel operations.  If we would check
+ *  in advance if the background was gray or RGB, and position the gray-to-RGB
+ *  transform appropriately, then it would save a lot of work/time.
+ */
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   /* If gray -> RGB, do so now only if background is non-gray; else do later
+    * for performance reasons
+    */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) == 0)
+      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+   if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+      png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   if ((png_ptr->transformations & PNG_GAMMA) != 0 &&
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+      /* Because RGB_TO_GRAY does the gamma transform. */
+      (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0 &&
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+      /* Because PNG_COMPOSE does the gamma transform if there is something to
+       * do (if there is an alpha channel or transparency.)
+       */
+       !((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       ((png_ptr->num_trans != 0) ||
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) &&
+#endif
+      /* Because png_init_read_transformations transforms the palette, unless
+       * RGB_TO_GRAY will do the transform.
+       */
+       (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
+      png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+       (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+       (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+       row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+          0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+   if ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+       (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+   if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
+      png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+   /* There is no harm in doing both of these because only one has any effect,
+    * by putting the 'scale' option first if the app asks for scale (either by
+    * calling the API or in a TRANSFORM flag) this is what happens.
+    */
+   if ((png_ptr->transformations & PNG_16_TO_8) != 0)
+      png_do_chop(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
+   {
+      png_do_quantize(row_info, png_ptr->row_buf + 1,
+          png_ptr->palette_lookup, png_ptr->quantize_index);
+
+      if (row_info->rowbytes == 0)
+         png_error(png_ptr, "png_do_quantize returned rowbytes=0");
+   }
+#endif /* READ_QUANTIZE */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   /* Do the expansion now, after all the arithmetic has been done.  Notice
+    * that previous transformations can handle the PNG_EXPAND_16 flag if this
+    * is efficient (particularly true in the case of gamma correction, where
+    * better accuracy results faster!)
+    */
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
+      png_do_expand_16(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   /* NOTE: moved here in 1.5.4 (from much later in this list.) */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) != 0)
+      png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_INVERT_SUPPORTED
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+      png_do_invert(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+      png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
+      png_do_unshift(row_info, png_ptr->row_buf + 1,
+          &(png_ptr->shift));
+#endif
+
+#ifdef PNG_READ_PACK_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACK) != 0)
+      png_do_unpack(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   /* Added at libpng-1.5.10 */
+   if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+       png_ptr->num_palette_max >= 0)
+      png_do_check_palette_indexes(png_ptr, row_info);
+#endif
+
+#ifdef PNG_READ_BGR_SUPPORTED
+   if ((png_ptr->transformations & PNG_BGR) != 0)
+      png_do_bgr(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+      png_do_packswap(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
+      png_do_read_filler(row_info, png_ptr->row_buf + 1,
+          (png_uint_32)png_ptr->filler, png_ptr->flags);
+#endif
+
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
+      png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+#ifdef PNG_READ_SWAP_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+      png_do_swap(row_info, png_ptr->row_buf + 1);
+#endif
+#endif
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+   {
+      if (png_ptr->read_user_transform_fn != NULL)
+         (*(png_ptr->read_user_transform_fn)) /* User read transform function */
+             (png_ptr,     /* png_ptr */
+             row_info,     /* row_info: */
+                /*  png_uint_32 width;       width of row */
+                /*  size_t rowbytes;         number of bytes in row */
+                /*  png_byte color_type;     color type of pixels */
+                /*  png_byte bit_depth;      bit depth of samples */
+                /*  png_byte channels;       number of channels (1-4) */
+                /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
+             png_ptr->row_buf + 1);    /* start of pixel data for row */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+      if (png_ptr->user_transform_depth != 0)
+         row_info->bit_depth = png_ptr->user_transform_depth;
+
+      if (png_ptr->user_transform_channels != 0)
+         row_info->channels = png_ptr->user_transform_channels;
+#endif
+      row_info->pixel_depth = (png_byte)(row_info->bit_depth *
+          row_info->channels);
+
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
+   }
+#endif
+}
+
+#endif /* READ_TRANSFORMS */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/pngrutil.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngrutil.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngrutil.c	(revision 107811)
@@ -0,0 +1,4680 @@
+
+/* pngrutil.c - utilities to read a PNG file
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file contains routines that are only called from within
+ * libpng itself during the course of reading an image.
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+png_uint_32 PNGAPI
+png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
+{
+   png_uint_32 uval = png_get_uint_32(buf);
+
+   if (uval > PNG_UINT_31_MAX)
+      png_error(png_ptr, "PNG unsigned integer out of range");
+
+   return uval;
+}
+
+#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
+/* The following is a variation on the above for use with the fixed
+ * point values used for gAMA and cHRM.  Instead of png_error it
+ * issues a warning and returns (-1) - an invalid value because both
+ * gAMA and cHRM use *unsigned* integers for fixed point values.
+ */
+#define PNG_FIXED_ERROR (-1)
+
+static png_fixed_point /* PRIVATE */
+png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
+{
+   png_uint_32 uval = png_get_uint_32(buf);
+
+   if (uval <= PNG_UINT_31_MAX)
+      return (png_fixed_point)uval; /* known to be in range */
+
+   /* The caller can turn off the warning by passing NULL. */
+   if (png_ptr != NULL)
+      png_warning(png_ptr, "PNG fixed point integer out of range");
+
+   return PNG_FIXED_ERROR;
+}
+#endif
+
+#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
+/* NOTE: the read macros will obscure these definitions, so that if
+ * PNG_USE_READ_MACROS is set the library will not use them internally,
+ * but the APIs will still be available externally.
+ *
+ * The parentheses around "PNGAPI function_name" in the following three
+ * functions are necessary because they allow the macros to co-exist with
+ * these (unused but exported) functions.
+ */
+
+/* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
+png_uint_32 (PNGAPI
+png_get_uint_32)(png_const_bytep buf)
+{
+   png_uint_32 uval =
+       ((png_uint_32)(*(buf    )) << 24) +
+       ((png_uint_32)(*(buf + 1)) << 16) +
+       ((png_uint_32)(*(buf + 2)) <<  8) +
+       ((png_uint_32)(*(buf + 3))      ) ;
+
+   return uval;
+}
+
+/* Grab a signed 32-bit integer from a buffer in big-endian format.  The
+ * data is stored in the PNG file in two's complement format and there
+ * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
+ * the following code does a two's complement to native conversion.
+ */
+png_int_32 (PNGAPI
+png_get_int_32)(png_const_bytep buf)
+{
+   png_uint_32 uval = png_get_uint_32(buf);
+   if ((uval & 0x80000000) == 0) /* non-negative */
+      return (png_int_32)uval;
+
+   uval = (uval ^ 0xffffffff) + 1;  /* 2's complement: -x = ~x+1 */
+   if ((uval & 0x80000000) == 0) /* no overflow */
+      return -(png_int_32)uval;
+   /* The following has to be safe; this function only gets called on PNG data
+    * and if we get here that data is invalid.  0 is the most safe value and
+    * if not then an attacker would surely just generate a PNG with 0 instead.
+    */
+   return 0;
+}
+
+/* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
+png_uint_16 (PNGAPI
+png_get_uint_16)(png_const_bytep buf)
+{
+   /* ANSI-C requires an int value to accommodate at least 16 bits so this
+    * works and allows the compiler not to worry about possible narrowing
+    * on 32-bit systems.  (Pre-ANSI systems did not make integers smaller
+    * than 16 bits either.)
+    */
+   unsigned int val =
+       ((unsigned int)(*buf) << 8) +
+       ((unsigned int)(*(buf + 1)));
+
+   return (png_uint_16)val;
+}
+
+#endif /* READ_INT_FUNCTIONS */
+
+/* Read and check the PNG file signature */
+void /* PRIVATE */
+png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
+{
+   size_t num_checked, num_to_check;
+
+   /* Exit if the user application does not expect a signature. */
+   if (png_ptr->sig_bytes >= 8)
+      return;
+
+   num_checked = png_ptr->sig_bytes;
+   num_to_check = 8 - num_checked;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
+#endif
+
+   /* The signature must be serialized in a single I/O call. */
+   png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
+   png_ptr->sig_bytes = 8;
+
+   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
+   {
+      if (num_checked < 4 &&
+          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4) != 0)
+         png_error(png_ptr, "Not a PNG file");
+      else
+         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+   }
+   if (num_checked < 3)
+      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
+/* Read the chunk header (length + type name).
+ * Put the type name into png_ptr->chunk_name, and return the length.
+ */
+png_uint_32 /* PRIVATE */
+png_read_chunk_header(png_structrp png_ptr)
+{
+   png_byte buf[8];
+   png_uint_32 length;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
+#endif
+
+   /* Read the length and the chunk name.
+    * This must be performed in a single I/O call.
+    */
+   png_read_data(png_ptr, buf, 8);
+   length = png_get_uint_31(png_ptr, buf);
+
+   /* Put the chunk name into png_ptr->chunk_name. */
+   png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
+
+   png_debug2(0, "Reading chunk typeid = 0x%lx, length = %lu",
+       (unsigned long)png_ptr->chunk_name, (unsigned long)length);
+
+   /* Reset the crc and run it over the chunk name. */
+   png_reset_crc(png_ptr);
+   png_calculate_crc(png_ptr, buf + 4, 4);
+
+   /* Check to see if chunk name is valid. */
+   png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+
+   /* Check for too-large chunk length */
+   png_check_chunk_length(png_ptr, length);
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
+#endif
+
+   return length;
+}
+
+/* Read data, and (optionally) run it through the CRC. */
+void /* PRIVATE */
+png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_read_data(png_ptr, buf, length);
+   png_calculate_crc(png_ptr, buf, length);
+}
+
+/* Optionally skip data and then check the CRC.  Depending on whether we
+ * are reading an ancillary or critical chunk, and how the program has set
+ * things up, we may calculate the CRC on the data and print a message.
+ * Returns '1' if there was a CRC error, '0' otherwise.
+ */
+int /* PRIVATE */
+png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
+{
+   /* The size of the local buffer for inflate is a good guess as to a
+    * reasonable size to use for buffering reads from the application.
+    */
+   while (skip > 0)
+   {
+      png_uint_32 len;
+      png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
+
+      len = (sizeof tmpbuf);
+      if (len > skip)
+         len = skip;
+      skip -= len;
+
+      png_crc_read(png_ptr, tmpbuf, len);
+   }
+
+   if (png_crc_error(png_ptr) != 0)
+   {
+      if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ?
+          (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 :
+          (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
+      {
+         png_chunk_warning(png_ptr, "CRC error");
+      }
+
+      else
+         png_chunk_error(png_ptr, "CRC error");
+
+      return 1;
+   }
+
+   return 0;
+}
+
+/* Compare the CRC stored in the PNG file with that calculated by libpng from
+ * the data it has read thus far.
+ */
+int /* PRIVATE */
+png_crc_error(png_structrp png_ptr)
+{
+   png_byte crc_bytes[4];
+   png_uint_32 crc;
+   int need_crc = 1;
+
+   if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
+          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
+         need_crc = 0;
+   }
+
+   else /* critical */
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
+         need_crc = 0;
+   }
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
+#endif
+
+   /* The chunk CRC must be serialized in a single I/O call. */
+   png_read_data(png_ptr, crc_bytes, 4);
+
+   if (need_crc != 0)
+   {
+      crc = png_get_uint_32(crc_bytes);
+      return crc != png_ptr->crc;
+   }
+
+   else
+      return 0;
+}
+
+#if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
+    defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
+    defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
+    defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+/* Manage the read buffer; this simply reallocates the buffer if it is not small
+ * enough (or if it is not allocated).  The routine returns a pointer to the
+ * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
+ * it will call png_error (via png_malloc) on failure.  (warn == 2 means
+ * 'silent').
+ */
+static png_bytep
+png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
+{
+   png_bytep buffer = png_ptr->read_buffer;
+
+   if (buffer != NULL && new_size > png_ptr->read_buffer_size)
+   {
+      png_ptr->read_buffer = NULL;
+      png_ptr->read_buffer_size = 0;
+      png_free(png_ptr, buffer);
+      buffer = NULL;
+   }
+
+   if (buffer == NULL)
+   {
+      buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
+
+      if (buffer != NULL)
+      {
+         memset(buffer, 0, new_size); /* just in case */
+         png_ptr->read_buffer = buffer;
+         png_ptr->read_buffer_size = new_size;
+      }
+
+      else if (warn < 2) /* else silent */
+      {
+         if (warn != 0)
+             png_chunk_warning(png_ptr, "insufficient memory to read chunk");
+
+         else
+             png_chunk_error(png_ptr, "insufficient memory to read chunk");
+      }
+   }
+
+   return buffer;
+}
+#endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
+
+/* png_inflate_claim: claim the zstream for some nefarious purpose that involves
+ * decompression.  Returns Z_OK on success, else a zlib error code.  It checks
+ * the owner but, in final release builds, just issues a warning if some other
+ * chunk apparently owns the stream.  Prior to release it does a png_error.
+ */
+static int
+png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
+{
+   if (png_ptr->zowner != 0)
+   {
+      char msg[64];
+
+      PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
+      /* So the message that results is "<chunk> using zstream"; this is an
+       * internal error, but is very useful for debugging.  i18n requirements
+       * are minimal.
+       */
+      (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
+#if PNG_RELEASE_BUILD
+      png_chunk_warning(png_ptr, msg);
+      png_ptr->zowner = 0;
+#else
+      png_chunk_error(png_ptr, msg);
+#endif
+   }
+
+   /* Implementation note: unlike 'png_deflate_claim' this internal function
+    * does not take the size of the data as an argument.  Some efficiency could
+    * be gained by using this when it is known *if* the zlib stream itself does
+    * not record the number; however, this is an illusion: the original writer
+    * of the PNG may have selected a lower window size, and we really must
+    * follow that because, for systems with with limited capabilities, we
+    * would otherwise reject the application's attempts to use a smaller window
+    * size (zlib doesn't have an interface to say "this or lower"!).
+    *
+    * inflateReset2 was added to zlib 1.2.4; before this the window could not be
+    * reset, therefore it is necessary to always allocate the maximum window
+    * size with earlier zlibs just in case later compressed chunks need it.
+    */
+   {
+      int ret; /* zlib return code */
+#if ZLIB_VERNUM >= 0x1240
+      int window_bits = 0;
+
+# if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
+      if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
+          PNG_OPTION_ON)
+      {
+         window_bits = 15;
+         png_ptr->zstream_start = 0; /* fixed window size */
+      }
+
+      else
+      {
+         png_ptr->zstream_start = 1;
+      }
+# endif
+
+#endif /* ZLIB_VERNUM >= 0x1240 */
+
+      /* Set this for safety, just in case the previous owner left pointers to
+       * memory allocations.
+       */
+      png_ptr->zstream.next_in = NULL;
+      png_ptr->zstream.avail_in = 0;
+      png_ptr->zstream.next_out = NULL;
+      png_ptr->zstream.avail_out = 0;
+
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+      {
+#if ZLIB_VERNUM >= 0x1240
+         ret = inflateReset2(&png_ptr->zstream, window_bits);
+#else
+         ret = inflateReset(&png_ptr->zstream);
+#endif
+      }
+
+      else
+      {
+#if ZLIB_VERNUM >= 0x1240
+         ret = inflateInit2(&png_ptr->zstream, window_bits);
+#else
+         ret = inflateInit(&png_ptr->zstream);
+#endif
+
+         if (ret == Z_OK)
+            png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
+      }
+
+#ifdef PNG_DISABLE_ADLER32_CHECK_SUPPORTED
+      if (((png_ptr->options >> PNG_IGNORE_ADLER32) & 3) == PNG_OPTION_ON)
+         /* Turn off validation of the ADLER32 checksum in IDAT chunks */
+         ret = inflateValidate(&png_ptr->zstream, 0);
+#endif
+
+      if (ret == Z_OK)
+         png_ptr->zowner = owner;
+
+      else
+         png_zstream_error(png_ptr, ret);
+
+      return ret;
+   }
+
+#ifdef window_bits
+# undef window_bits
+#endif
+}
+
+#if ZLIB_VERNUM >= 0x1240
+/* Handle the start of the inflate stream if we called inflateInit2(strm,0);
+ * in this case some zlib versions skip validation of the CINFO field and, in
+ * certain circumstances, libpng may end up displaying an invalid image, in
+ * contrast to implementations that call zlib in the normal way (e.g. libpng
+ * 1.5).
+ */
+int /* PRIVATE */
+png_zlib_inflate(png_structrp png_ptr, int flush)
+{
+   if (png_ptr->zstream_start && png_ptr->zstream.avail_in > 0)
+   {
+      if ((*png_ptr->zstream.next_in >> 4) > 7)
+      {
+         png_ptr->zstream.msg = "invalid window size (libpng)";
+         return Z_DATA_ERROR;
+      }
+
+      png_ptr->zstream_start = 0;
+   }
+
+   return inflate(&png_ptr->zstream, flush);
+}
+#endif /* Zlib >= 1.2.4 */
+
+#ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
+#if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
+/* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
+ * allow the caller to do multiple calls if required.  If the 'finish' flag is
+ * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
+ * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
+ * Z_OK or Z_STREAM_END will be returned on success.
+ *
+ * The input and output sizes are updated to the actual amounts of data consumed
+ * or written, not the amount available (as in a z_stream).  The data pointers
+ * are not changed, so the next input is (data+input_size) and the next
+ * available output is (output+output_size).
+ */
+static int
+png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
+    /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
+    /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
+{
+   if (png_ptr->zowner == owner) /* Else not claimed */
+   {
+      int ret;
+      png_alloc_size_t avail_out = *output_size_ptr;
+      png_uint_32 avail_in = *input_size_ptr;
+
+      /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
+       * can't even necessarily handle 65536 bytes) because the type uInt is
+       * "16 bits or more".  Consequently it is necessary to chunk the input to
+       * zlib.  This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
+       * maximum value that can be stored in a uInt.)  It is possible to set
+       * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
+       * a performance advantage, because it reduces the amount of data accessed
+       * at each step and that may give the OS more time to page it in.
+       */
+      png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
+      /* avail_in and avail_out are set below from 'size' */
+      png_ptr->zstream.avail_in = 0;
+      png_ptr->zstream.avail_out = 0;
+
+      /* Read directly into the output if it is available (this is set to
+       * a local buffer below if output is NULL).
+       */
+      if (output != NULL)
+         png_ptr->zstream.next_out = output;
+
+      do
+      {
+         uInt avail;
+         Byte local_buffer[PNG_INFLATE_BUF_SIZE];
+
+         /* zlib INPUT BUFFER */
+         /* The setting of 'avail_in' used to be outside the loop; by setting it
+          * inside it is possible to chunk the input to zlib and simply rely on
+          * zlib to advance the 'next_in' pointer.  This allows arbitrary
+          * amounts of data to be passed through zlib at the unavoidable cost of
+          * requiring a window save (memcpy of up to 32768 output bytes)
+          * every ZLIB_IO_MAX input bytes.
+          */
+         avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
+
+         avail = ZLIB_IO_MAX;
+
+         if (avail_in < avail)
+            avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
+
+         avail_in -= avail;
+         png_ptr->zstream.avail_in = avail;
+
+         /* zlib OUTPUT BUFFER */
+         avail_out += png_ptr->zstream.avail_out; /* not written last time */
+
+         avail = ZLIB_IO_MAX; /* maximum zlib can process */
+
+         if (output == NULL)
+         {
+            /* Reset the output buffer each time round if output is NULL and
+             * make available the full buffer, up to 'remaining_space'
+             */
+            png_ptr->zstream.next_out = local_buffer;
+            if ((sizeof local_buffer) < avail)
+               avail = (sizeof local_buffer);
+         }
+
+         if (avail_out < avail)
+            avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
+
+         png_ptr->zstream.avail_out = avail;
+         avail_out -= avail;
+
+         /* zlib inflate call */
+         /* In fact 'avail_out' may be 0 at this point, that happens at the end
+          * of the read when the final LZ end code was not passed at the end of
+          * the previous chunk of input data.  Tell zlib if we have reached the
+          * end of the output buffer.
+          */
+         ret = PNG_INFLATE(png_ptr, avail_out > 0 ? Z_NO_FLUSH :
+             (finish ? Z_FINISH : Z_SYNC_FLUSH));
+      } while (ret == Z_OK);
+
+      /* For safety kill the local buffer pointer now */
+      if (output == NULL)
+         png_ptr->zstream.next_out = NULL;
+
+      /* Claw back the 'size' and 'remaining_space' byte counts. */
+      avail_in += png_ptr->zstream.avail_in;
+      avail_out += png_ptr->zstream.avail_out;
+
+      /* Update the input and output sizes; the updated values are the amount
+       * consumed or written, effectively the inverse of what zlib uses.
+       */
+      if (avail_out > 0)
+         *output_size_ptr -= avail_out;
+
+      if (avail_in > 0)
+         *input_size_ptr -= avail_in;
+
+      /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
+      png_zstream_error(png_ptr, ret);
+      return ret;
+   }
+
+   else
+   {
+      /* This is a bad internal error.  The recovery assigns to the zstream msg
+       * pointer, which is not owned by the caller, but this is safe; it's only
+       * used on errors!
+       */
+      png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
+      return Z_STREAM_ERROR;
+   }
+}
+
+/*
+ * Decompress trailing data in a chunk.  The assumption is that read_buffer
+ * points at an allocated area holding the contents of a chunk with a
+ * trailing compressed part.  What we get back is an allocated area
+ * holding the original prefix part and an uncompressed version of the
+ * trailing part (the malloc area passed in is freed).
+ */
+static int
+png_decompress_chunk(png_structrp png_ptr,
+    png_uint_32 chunklength, png_uint_32 prefix_size,
+    png_alloc_size_t *newlength /* must be initialized to the maximum! */,
+    int terminate /*add a '\0' to the end of the uncompressed data*/)
+{
+   /* TODO: implement different limits for different types of chunk.
+    *
+    * The caller supplies *newlength set to the maximum length of the
+    * uncompressed data, but this routine allocates space for the prefix and
+    * maybe a '\0' terminator too.  We have to assume that 'prefix_size' is
+    * limited only by the maximum chunk size.
+    */
+   png_alloc_size_t limit = PNG_SIZE_MAX;
+
+# ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_malloc_max > 0 &&
+       png_ptr->user_chunk_malloc_max < limit)
+      limit = png_ptr->user_chunk_malloc_max;
+# elif PNG_USER_CHUNK_MALLOC_MAX > 0
+   if (PNG_USER_CHUNK_MALLOC_MAX < limit)
+      limit = PNG_USER_CHUNK_MALLOC_MAX;
+# endif
+
+   if (limit >= prefix_size + (terminate != 0))
+   {
+      int ret;
+
+      limit -= prefix_size + (terminate != 0);
+
+      if (limit < *newlength)
+         *newlength = limit;
+
+      /* Now try to claim the stream. */
+      ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
+
+      if (ret == Z_OK)
+      {
+         png_uint_32 lzsize = chunklength - prefix_size;
+
+         ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
+             /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
+             /* output: */ NULL, newlength);
+
+         if (ret == Z_STREAM_END)
+         {
+            /* Use 'inflateReset' here, not 'inflateReset2' because this
+             * preserves the previously decided window size (otherwise it would
+             * be necessary to store the previous window size.)  In practice
+             * this doesn't matter anyway, because png_inflate will call inflate
+             * with Z_FINISH in almost all cases, so the window will not be
+             * maintained.
+             */
+            if (inflateReset(&png_ptr->zstream) == Z_OK)
+            {
+               /* Because of the limit checks above we know that the new,
+                * expanded, size will fit in a size_t (let alone an
+                * png_alloc_size_t).  Use png_malloc_base here to avoid an
+                * extra OOM message.
+                */
+               png_alloc_size_t new_size = *newlength;
+               png_alloc_size_t buffer_size = prefix_size + new_size +
+                   (terminate != 0);
+               png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
+                   buffer_size));
+
+               if (text != NULL)
+               {
+                  memset(text, 0, buffer_size);
+
+                  ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
+                      png_ptr->read_buffer + prefix_size, &lzsize,
+                      text + prefix_size, newlength);
+
+                  if (ret == Z_STREAM_END)
+                  {
+                     if (new_size == *newlength)
+                     {
+                        if (terminate != 0)
+                           text[prefix_size + *newlength] = 0;
+
+                        if (prefix_size > 0)
+                           memcpy(text, png_ptr->read_buffer, prefix_size);
+
+                        {
+                           png_bytep old_ptr = png_ptr->read_buffer;
+
+                           png_ptr->read_buffer = text;
+                           png_ptr->read_buffer_size = buffer_size;
+                           text = old_ptr; /* freed below */
+                        }
+                     }
+
+                     else
+                     {
+                        /* The size changed on the second read, there can be no
+                         * guarantee that anything is correct at this point.
+                         * The 'msg' pointer has been set to "unexpected end of
+                         * LZ stream", which is fine, but return an error code
+                         * that the caller won't accept.
+                         */
+                        ret = PNG_UNEXPECTED_ZLIB_RETURN;
+                     }
+                  }
+
+                  else if (ret == Z_OK)
+                     ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
+
+                  /* Free the text pointer (this is the old read_buffer on
+                   * success)
+                   */
+                  png_free(png_ptr, text);
+
+                  /* This really is very benign, but it's still an error because
+                   * the extra space may otherwise be used as a Trojan Horse.
+                   */
+                  if (ret == Z_STREAM_END &&
+                      chunklength - prefix_size != lzsize)
+                     png_chunk_benign_error(png_ptr, "extra compressed data");
+               }
+
+               else
+               {
+                  /* Out of memory allocating the buffer */
+                  ret = Z_MEM_ERROR;
+                  png_zstream_error(png_ptr, Z_MEM_ERROR);
+               }
+            }
+
+            else
+            {
+               /* inflateReset failed, store the error message */
+               png_zstream_error(png_ptr, ret);
+               ret = PNG_UNEXPECTED_ZLIB_RETURN;
+            }
+         }
+
+         else if (ret == Z_OK)
+            ret = PNG_UNEXPECTED_ZLIB_RETURN;
+
+         /* Release the claimed stream */
+         png_ptr->zowner = 0;
+      }
+
+      else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
+         ret = PNG_UNEXPECTED_ZLIB_RETURN;
+
+      return ret;
+   }
+
+   else
+   {
+      /* Application/configuration limits exceeded */
+      png_zstream_error(png_ptr, Z_MEM_ERROR);
+      return Z_MEM_ERROR;
+   }
+}
+#endif /* READ_zTXt || READ_iTXt */
+#endif /* READ_COMPRESSED_TEXT */
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+/* Perform a partial read and decompress, producing 'avail_out' bytes and
+ * reading from the current chunk as required.
+ */
+static int
+png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
+    png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
+    int finish)
+{
+   if (png_ptr->zowner == png_ptr->chunk_name)
+   {
+      int ret;
+
+      /* next_in and avail_in must have been initialized by the caller. */
+      png_ptr->zstream.next_out = next_out;
+      png_ptr->zstream.avail_out = 0; /* set in the loop */
+
+      do
+      {
+         if (png_ptr->zstream.avail_in == 0)
+         {
+            if (read_size > *chunk_bytes)
+               read_size = (uInt)*chunk_bytes;
+            *chunk_bytes -= read_size;
+
+            if (read_size > 0)
+               png_crc_read(png_ptr, read_buffer, read_size);
+
+            png_ptr->zstream.next_in = read_buffer;
+            png_ptr->zstream.avail_in = read_size;
+         }
+
+         if (png_ptr->zstream.avail_out == 0)
+         {
+            uInt avail = ZLIB_IO_MAX;
+            if (avail > *out_size)
+               avail = (uInt)*out_size;
+            *out_size -= avail;
+
+            png_ptr->zstream.avail_out = avail;
+         }
+
+         /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
+          * the available output is produced; this allows reading of truncated
+          * streams.
+          */
+         ret = PNG_INFLATE(png_ptr, *chunk_bytes > 0 ?
+             Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
+      }
+      while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
+
+      *out_size += png_ptr->zstream.avail_out;
+      png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
+
+      /* Ensure the error message pointer is always set: */
+      png_zstream_error(png_ptr, ret);
+      return ret;
+   }
+
+   else
+   {
+      png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
+      return Z_STREAM_ERROR;
+   }
+}
+#endif /* READ_iCCP */
+
+/* Read and check the IDHR chunk */
+
+void /* PRIVATE */
+png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[13];
+   png_uint_32 width, height;
+   int bit_depth, color_type, compression_type, filter_type;
+   int interlace_type;
+
+   png_debug(1, "in png_handle_IHDR");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) != 0)
+      png_chunk_error(png_ptr, "out of place");
+
+   /* Check the length */
+   if (length != 13)
+      png_chunk_error(png_ptr, "invalid");
+
+   png_ptr->mode |= PNG_HAVE_IHDR;
+
+   png_crc_read(png_ptr, buf, 13);
+   png_crc_finish(png_ptr, 0);
+
+   width = png_get_uint_31(png_ptr, buf);
+   height = png_get_uint_31(png_ptr, buf + 4);
+   bit_depth = buf[8];
+   color_type = buf[9];
+   compression_type = buf[10];
+   filter_type = buf[11];
+   interlace_type = buf[12];
+
+   /* Set internal variables */
+   png_ptr->width = width;
+   png_ptr->height = height;
+   png_ptr->bit_depth = (png_byte)bit_depth;
+   png_ptr->interlaced = (png_byte)interlace_type;
+   png_ptr->color_type = (png_byte)color_type;
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   png_ptr->filter_type = (png_byte)filter_type;
+#endif
+   png_ptr->compression_type = (png_byte)compression_type;
+
+   /* Find number of channels */
+   switch (png_ptr->color_type)
+   {
+      default: /* invalid, png_set_IHDR calls png_error */
+      case PNG_COLOR_TYPE_GRAY:
+      case PNG_COLOR_TYPE_PALETTE:
+         png_ptr->channels = 1;
+         break;
+
+      case PNG_COLOR_TYPE_RGB:
+         png_ptr->channels = 3;
+         break;
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         png_ptr->channels = 2;
+         break;
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         png_ptr->channels = 4;
+         break;
+   }
+
+   /* Set up other useful info */
+   png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
+   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
+   png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
+   png_debug1(3, "channels = %d", png_ptr->channels);
+   png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
+   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
+       color_type, interlace_type, compression_type, filter_type);
+}
+
+/* Read and check the palette */
+void /* PRIVATE */
+png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_color palette[PNG_MAX_PALETTE_LENGTH];
+   int max_palette_length, num, i;
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+   png_colorp pal_ptr;
+#endif
+
+   png_debug(1, "in png_handle_PLTE");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   /* Moved to before the 'after IDAT' check below because otherwise duplicate
+    * PLTE chunks are potentially ignored (the spec says there shall not be more
+    * than one PLTE, the error is not treated as benign, so this check trumps
+    * the requirement that PLTE appears before IDAT.)
+    */
+   else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0)
+      png_chunk_error(png_ptr, "duplicate");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      /* This is benign because the non-benign error happened before, when an
+       * IDAT was encountered in a color-mapped image with no PLTE.
+       */
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   png_ptr->mode |= PNG_HAVE_PLTE;
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
+      return;
+   }
+
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
+   if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+#endif
+
+   if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
+   {
+      png_crc_finish(png_ptr, length);
+
+      if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+         png_chunk_benign_error(png_ptr, "invalid");
+
+      else
+         png_chunk_error(png_ptr, "invalid");
+
+      return;
+   }
+
+   /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
+   num = (int)length / 3;
+
+   /* If the palette has 256 or fewer entries but is too large for the bit
+    * depth, we don't issue an error, to preserve the behavior of previous
+    * libpng versions. We silently truncate the unused extra palette entries
+    * here.
+    */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      max_palette_length = (1 << png_ptr->bit_depth);
+   else
+      max_palette_length = PNG_MAX_PALETTE_LENGTH;
+
+   if (num > max_palette_length)
+      num = max_palette_length;
+
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+   for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
+   {
+      png_byte buf[3];
+
+      png_crc_read(png_ptr, buf, 3);
+      pal_ptr->red = buf[0];
+      pal_ptr->green = buf[1];
+      pal_ptr->blue = buf[2];
+   }
+#else
+   for (i = 0; i < num; i++)
+   {
+      png_byte buf[3];
+
+      png_crc_read(png_ptr, buf, 3);
+      /* Don't depend upon png_color being any order */
+      palette[i].red = buf[0];
+      palette[i].green = buf[1];
+      palette[i].blue = buf[2];
+   }
+#endif
+
+   /* If we actually need the PLTE chunk (ie for a paletted image), we do
+    * whatever the normal CRC configuration tells us.  However, if we
+    * have an RGB image, the PLTE can be considered ancillary, so
+    * we will act as though it is.
+    */
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#endif
+   {
+      png_crc_finish(png_ptr, (png_uint_32) (length - (unsigned int)num * 3));
+   }
+
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
+   else if (png_crc_error(png_ptr) != 0)  /* Only if we have a CRC error */
+   {
+      /* If we don't want to use the data from an ancillary chunk,
+       * we have two options: an error abort, or a warning and we
+       * ignore the data in this chunk (which should be OK, since
+       * it's considered ancillary for a RGB or RGBA image).
+       *
+       * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
+       * chunk type to determine whether to check the ancillary or the critical
+       * flags.
+       */
+      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0)
+      {
+         if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0)
+            return;
+
+         else
+            png_chunk_error(png_ptr, "CRC error");
+      }
+
+      /* Otherwise, we (optionally) emit a warning and use the chunk. */
+      else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0)
+         png_chunk_warning(png_ptr, "CRC error");
+   }
+#endif
+
+   /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
+    * own copy of the palette.  This has the side effect that when png_start_row
+    * is called (this happens after any call to png_read_update_info) the
+    * info_ptr palette gets changed.  This is extremely unexpected and
+    * confusing.
+    *
+    * Fix this by not sharing the palette in this way.
+    */
+   png_set_PLTE(png_ptr, info_ptr, palette, num);
+
+   /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
+    * IDAT.  Prior to 1.6.0 this was not checked; instead the code merely
+    * checked the apparent validity of a tRNS chunk inserted before PLTE on a
+    * palette PNG.  1.6.0 attempts to rigorously follow the standard and
+    * therefore does a benign error if the erroneous condition is detected *and*
+    * cancels the tRNS if the benign error returns.  The alternative is to
+    * amend the standard since it would be rather hypocritical of the standards
+    * maintainers to ignore it.
+    */
+#ifdef PNG_READ_tRNS_SUPPORTED
+   if (png_ptr->num_trans > 0 ||
+       (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
+   {
+      /* Cancel this because otherwise it would be used if the transforms
+       * require it.  Don't cancel the 'valid' flag because this would prevent
+       * detection of duplicate chunks.
+       */
+      png_ptr->num_trans = 0;
+
+      if (info_ptr != NULL)
+         info_ptr->num_trans = 0;
+
+      png_chunk_benign_error(png_ptr, "tRNS must be after");
+   }
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
+      png_chunk_benign_error(png_ptr, "hIST must be after");
+#endif
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
+      png_chunk_benign_error(png_ptr, "bKGD must be after");
+#endif
+}
+
+void /* PRIVATE */
+png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_debug(1, "in png_handle_IEND");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 ||
+       (png_ptr->mode & PNG_HAVE_IDAT) == 0)
+      png_chunk_error(png_ptr, "out of place");
+
+   png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
+
+   png_crc_finish(png_ptr, length);
+
+   if (length != 0)
+      png_chunk_benign_error(png_ptr, "invalid");
+
+   PNG_UNUSED(info_ptr)
+}
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+void /* PRIVATE */
+png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_fixed_point igamma;
+   png_byte buf[4];
+
+   png_debug(1, "in png_handle_gAMA");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   if (length != 4)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 4);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   igamma = png_get_fixed_point(NULL, buf);
+
+   png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
+   png_colorspace_sync(png_ptr, info_ptr);
+}
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+void /* PRIVATE */
+png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   unsigned int truelen, i;
+   png_byte sample_depth;
+   png_byte buf[4];
+
+   png_debug(1, "in png_handle_sBIT");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      truelen = 3;
+      sample_depth = 8;
+   }
+
+   else
+   {
+      truelen = png_ptr->channels;
+      sample_depth = png_ptr->bit_depth;
+   }
+
+   if (length != truelen || length > 4)
+   {
+      png_chunk_benign_error(png_ptr, "invalid");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
+   png_crc_read(png_ptr, buf, truelen);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   for (i=0; i<truelen; ++i)
+   {
+      if (buf[i] == 0 || buf[i] > sample_depth)
+      {
+         png_chunk_benign_error(png_ptr, "invalid");
+         return;
+      }
+   }
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_ptr->sig_bit.red = buf[0];
+      png_ptr->sig_bit.green = buf[1];
+      png_ptr->sig_bit.blue = buf[2];
+      png_ptr->sig_bit.alpha = buf[3];
+   }
+
+   else
+   {
+      png_ptr->sig_bit.gray = buf[0];
+      png_ptr->sig_bit.red = buf[0];
+      png_ptr->sig_bit.green = buf[0];
+      png_ptr->sig_bit.blue = buf[0];
+      png_ptr->sig_bit.alpha = buf[1];
+   }
+
+   png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
+}
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+void /* PRIVATE */
+png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[32];
+   png_xy xy;
+
+   png_debug(1, "in png_handle_cHRM");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   if (length != 32)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 32);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   xy.whitex = png_get_fixed_point(NULL, buf);
+   xy.whitey = png_get_fixed_point(NULL, buf + 4);
+   xy.redx   = png_get_fixed_point(NULL, buf + 8);
+   xy.redy   = png_get_fixed_point(NULL, buf + 12);
+   xy.greenx = png_get_fixed_point(NULL, buf + 16);
+   xy.greeny = png_get_fixed_point(NULL, buf + 20);
+   xy.bluex  = png_get_fixed_point(NULL, buf + 24);
+   xy.bluey  = png_get_fixed_point(NULL, buf + 28);
+
+   if (xy.whitex == PNG_FIXED_ERROR ||
+       xy.whitey == PNG_FIXED_ERROR ||
+       xy.redx   == PNG_FIXED_ERROR ||
+       xy.redy   == PNG_FIXED_ERROR ||
+       xy.greenx == PNG_FIXED_ERROR ||
+       xy.greeny == PNG_FIXED_ERROR ||
+       xy.bluex  == PNG_FIXED_ERROR ||
+       xy.bluey  == PNG_FIXED_ERROR)
+   {
+      png_chunk_benign_error(png_ptr, "invalid values");
+      return;
+   }
+
+   /* If a colorspace error has already been output skip this chunk */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+      return;
+
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0)
+   {
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
+      png_colorspace_sync(png_ptr, info_ptr);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+   (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
+       1/*prefer cHRM values*/);
+   png_colorspace_sync(png_ptr, info_ptr);
+}
+#endif
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+void /* PRIVATE */
+png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte intent;
+
+   png_debug(1, "in png_handle_sRGB");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   if (length != 1)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, &intent, 1);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* If a colorspace error has already been output skip this chunk */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+      return;
+
+   /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
+    * this.
+    */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0)
+   {
+      png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
+      png_colorspace_sync(png_ptr, info_ptr);
+      png_chunk_benign_error(png_ptr, "too many profiles");
+      return;
+   }
+
+   (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
+   png_colorspace_sync(png_ptr, info_ptr);
+}
+#endif /* READ_sRGB */
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+void /* PRIVATE */
+png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+/* Note: this does not properly handle profiles that are > 64K under DOS */
+{
+   png_const_charp errmsg = NULL; /* error message output, or no error */
+   int finished = 0; /* crc checked */
+
+   png_debug(1, "in png_handle_iCCP");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   /* Consistent with all the above colorspace handling an obviously *invalid*
+    * chunk is just ignored, so does not invalidate the color space.  An
+    * alternative is to set the 'invalid' flags at the start of this routine
+    * and only clear them in they were not set before and all the tests pass.
+    */
+
+   /* The keyword must be at least one character and there is a
+    * terminator (0) byte and the compression method byte, and the
+    * 'zlib' datastream is at least 11 bytes.
+    */
+   if (length < 14)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "too short");
+      return;
+   }
+
+   /* If a colorspace error has already been output skip this chunk */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
+    * this.
+    */
+   if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
+   {
+      uInt read_length, keyword_length;
+      char keyword[81];
+
+      /* Find the keyword; the keyword plus separator and compression method
+       * bytes can be at most 81 characters long.
+       */
+      read_length = 81; /* maximum */
+      if (read_length > length)
+         read_length = (uInt)length;
+
+      png_crc_read(png_ptr, (png_bytep)keyword, read_length);
+      length -= read_length;
+
+      /* The minimum 'zlib' stream is assumed to be just the 2 byte header,
+       * 5 bytes minimum 'deflate' stream, and the 4 byte checksum.
+       */
+      if (length < 11)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "too short");
+         return;
+      }
+
+      keyword_length = 0;
+      while (keyword_length < 80 && keyword_length < read_length &&
+         keyword[keyword_length] != 0)
+         ++keyword_length;
+
+      /* TODO: make the keyword checking common */
+      if (keyword_length >= 1 && keyword_length <= 79)
+      {
+         /* We only understand '0' compression - deflate - so if we get a
+          * different value we can't safely decode the chunk.
+          */
+         if (keyword_length+1 < read_length &&
+            keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
+         {
+            read_length -= keyword_length+2;
+
+            if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
+            {
+               Byte profile_header[132]={0};
+               Byte local_buffer[PNG_INFLATE_BUF_SIZE];
+               png_alloc_size_t size = (sizeof profile_header);
+
+               png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
+               png_ptr->zstream.avail_in = read_length;
+               (void)png_inflate_read(png_ptr, local_buffer,
+                   (sizeof local_buffer), &length, profile_header, &size,
+                   0/*finish: don't, because the output is too small*/);
+
+               if (size == 0)
+               {
+                  /* We have the ICC profile header; do the basic header checks.
+                   */
+                  png_uint_32 profile_length = png_get_uint_32(profile_header);
+
+                  if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
+                      keyword, profile_length) != 0)
+                  {
+                     /* The length is apparently ok, so we can check the 132
+                      * byte header.
+                      */
+                     if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
+                         keyword, profile_length, profile_header,
+                         png_ptr->color_type) != 0)
+                     {
+                        /* Now read the tag table; a variable size buffer is
+                         * needed at this point, allocate one for the whole
+                         * profile.  The header check has already validated
+                         * that none of this stuff will overflow.
+                         */
+                        png_uint_32 tag_count =
+                           png_get_uint_32(profile_header + 128);
+                        png_bytep profile = png_read_buffer(png_ptr,
+                            profile_length, 2/*silent*/);
+
+                        if (profile != NULL)
+                        {
+                           memcpy(profile, profile_header,
+                               (sizeof profile_header));
+
+                           size = 12 * tag_count;
+
+                           (void)png_inflate_read(png_ptr, local_buffer,
+                               (sizeof local_buffer), &length,
+                               profile + (sizeof profile_header), &size, 0);
+
+                           /* Still expect a buffer error because we expect
+                            * there to be some tag data!
+                            */
+                           if (size == 0)
+                           {
+                              if (png_icc_check_tag_table(png_ptr,
+                                  &png_ptr->colorspace, keyword, profile_length,
+                                  profile) != 0)
+                              {
+                                 /* The profile has been validated for basic
+                                  * security issues, so read the whole thing in.
+                                  */
+                                 size = profile_length - (sizeof profile_header)
+                                     - 12 * tag_count;
+
+                                 (void)png_inflate_read(png_ptr, local_buffer,
+                                     (sizeof local_buffer), &length,
+                                     profile + (sizeof profile_header) +
+                                     12 * tag_count, &size, 1/*finish*/);
+
+                                 if (length > 0 && !(png_ptr->flags &
+                                     PNG_FLAG_BENIGN_ERRORS_WARN))
+                                    errmsg = "extra compressed data";
+
+                                 /* But otherwise allow extra data: */
+                                 else if (size == 0)
+                                 {
+                                    if (length > 0)
+                                    {
+                                       /* This can be handled completely, so
+                                        * keep going.
+                                        */
+                                       png_chunk_warning(png_ptr,
+                                           "extra compressed data");
+                                    }
+
+                                    png_crc_finish(png_ptr, length);
+                                    finished = 1;
+
+# if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
+                                    /* Check for a match against sRGB */
+                                    png_icc_set_sRGB(png_ptr,
+                                        &png_ptr->colorspace, profile,
+                                        png_ptr->zstream.adler);
+# endif
+
+                                    /* Steal the profile for info_ptr. */
+                                    if (info_ptr != NULL)
+                                    {
+                                       png_free_data(png_ptr, info_ptr,
+                                           PNG_FREE_ICCP, 0);
+
+                                       info_ptr->iccp_name = png_voidcast(char*,
+                                           png_malloc_base(png_ptr,
+                                           keyword_length+1));
+                                       if (info_ptr->iccp_name != NULL)
+                                       {
+                                          memcpy(info_ptr->iccp_name, keyword,
+                                              keyword_length+1);
+                                          info_ptr->iccp_proflen =
+                                              profile_length;
+                                          info_ptr->iccp_profile = profile;
+                                          png_ptr->read_buffer = NULL; /*steal*/
+                                          info_ptr->free_me |= PNG_FREE_ICCP;
+                                          info_ptr->valid |= PNG_INFO_iCCP;
+                                       }
+
+                                       else
+                                       {
+                                          png_ptr->colorspace.flags |=
+                                             PNG_COLORSPACE_INVALID;
+                                          errmsg = "out of memory";
+                                       }
+                                    }
+
+                                    /* else the profile remains in the read
+                                     * buffer which gets reused for subsequent
+                                     * chunks.
+                                     */
+
+                                    if (info_ptr != NULL)
+                                       png_colorspace_sync(png_ptr, info_ptr);
+
+                                    if (errmsg == NULL)
+                                    {
+                                       png_ptr->zowner = 0;
+                                       return;
+                                    }
+                                 }
+                                 if (errmsg == NULL)
+                                    errmsg = png_ptr->zstream.msg;
+                              }
+                              /* else png_icc_check_tag_table output an error */
+                           }
+                           else /* profile truncated */
+                              errmsg = png_ptr->zstream.msg;
+                        }
+
+                        else
+                           errmsg = "out of memory";
+                     }
+
+                     /* else png_icc_check_header output an error */
+                  }
+
+                  /* else png_icc_check_length output an error */
+               }
+
+               else /* profile truncated */
+                  errmsg = png_ptr->zstream.msg;
+
+               /* Release the stream */
+               png_ptr->zowner = 0;
+            }
+
+            else /* png_inflate_claim failed */
+               errmsg = png_ptr->zstream.msg;
+         }
+
+         else
+            errmsg = "bad compression method"; /* or missing */
+      }
+
+      else
+         errmsg = "bad keyword";
+   }
+
+   else
+      errmsg = "too many profiles";
+
+   /* Failure: the reason is in 'errmsg' */
+   if (finished == 0)
+      png_crc_finish(png_ptr, length);
+
+   png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
+   png_colorspace_sync(png_ptr, info_ptr);
+   if (errmsg != NULL) /* else already output */
+      png_chunk_benign_error(png_ptr, errmsg);
+}
+#endif /* READ_iCCP */
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+void /* PRIVATE */
+png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+{
+   png_bytep entry_start, buffer;
+   png_sPLT_t new_palette;
+   png_sPLT_entryp pp;
+   png_uint_32 data_length;
+   int entry_size, i;
+   png_uint_32 skip = 0;
+   png_uint_32 dl;
+   size_t max_dl;
+
+   png_debug(1, "in png_handle_sPLT");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_warning(png_ptr, "No space in chunk cache for sPLT");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (length > 65535U)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "too large to fit in memory");
+      return;
+   }
+#endif
+
+   buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
+   if (buffer == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+
+   /* WARNING: this may break if size_t is less than 32 bits; it is assumed
+    * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
+    * potential breakage point if the types in pngconf.h aren't exactly right.
+    */
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, skip) != 0)
+      return;
+
+   buffer[length] = 0;
+
+   for (entry_start = buffer; *entry_start; entry_start++)
+      /* Empty loop to find end of name */ ;
+
+   ++entry_start;
+
+   /* A sample depth should follow the separator, and we should be on it  */
+   if (length < 2U || entry_start > buffer + (length - 2U))
+   {
+      png_warning(png_ptr, "malformed sPLT chunk");
+      return;
+   }
+
+   new_palette.depth = *entry_start++;
+   entry_size = (new_palette.depth == 8 ? 6 : 10);
+   /* This must fit in a png_uint_32 because it is derived from the original
+    * chunk data length.
+    */
+   data_length = length - (png_uint_32)(entry_start - buffer);
+
+   /* Integrity-check the data length */
+   if ((data_length % (unsigned int)entry_size) != 0)
+   {
+      png_warning(png_ptr, "sPLT chunk has bad length");
+      return;
+   }
+
+   dl = (png_uint_32)(data_length / (unsigned int)entry_size);
+   max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
+
+   if (dl > max_dl)
+   {
+      png_warning(png_ptr, "sPLT chunk too long");
+      return;
+   }
+
+   new_palette.nentries = (png_int_32)(data_length / (unsigned int)entry_size);
+
+   new_palette.entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
+       (png_alloc_size_t) new_palette.nentries * (sizeof (png_sPLT_entry)));
+
+   if (new_palette.entries == NULL)
+   {
+      png_warning(png_ptr, "sPLT chunk requires too much memory");
+      return;
+   }
+
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+   for (i = 0; i < new_palette.nentries; i++)
+   {
+      pp = new_palette.entries + i;
+
+      if (new_palette.depth == 8)
+      {
+         pp->red = *entry_start++;
+         pp->green = *entry_start++;
+         pp->blue = *entry_start++;
+         pp->alpha = *entry_start++;
+      }
+
+      else
+      {
+         pp->red   = png_get_uint_16(entry_start); entry_start += 2;
+         pp->green = png_get_uint_16(entry_start); entry_start += 2;
+         pp->blue  = png_get_uint_16(entry_start); entry_start += 2;
+         pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
+      }
+
+      pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
+   }
+#else
+   pp = new_palette.entries;
+
+   for (i = 0; i < new_palette.nentries; i++)
+   {
+
+      if (new_palette.depth == 8)
+      {
+         pp[i].red   = *entry_start++;
+         pp[i].green = *entry_start++;
+         pp[i].blue  = *entry_start++;
+         pp[i].alpha = *entry_start++;
+      }
+
+      else
+      {
+         pp[i].red   = png_get_uint_16(entry_start); entry_start += 2;
+         pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
+         pp[i].blue  = png_get_uint_16(entry_start); entry_start += 2;
+         pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
+      }
+
+      pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
+   }
+#endif
+
+   /* Discard all chunk data except the name and stash that */
+   new_palette.name = (png_charp)buffer;
+
+   png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
+
+   png_free(png_ptr, new_palette.entries);
+}
+#endif /* READ_sPLT */
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+void /* PRIVATE */
+png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
+
+   png_debug(1, "in png_handle_tRNS");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      png_byte buf[2];
+
+      if (length != 2)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "invalid");
+         return;
+      }
+
+      png_crc_read(png_ptr, buf, 2);
+      png_ptr->num_trans = 1;
+      png_ptr->trans_color.gray = png_get_uint_16(buf);
+   }
+
+   else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+   {
+      png_byte buf[6];
+
+      if (length != 6)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "invalid");
+         return;
+      }
+
+      png_crc_read(png_ptr, buf, length);
+      png_ptr->num_trans = 1;
+      png_ptr->trans_color.red = png_get_uint_16(buf);
+      png_ptr->trans_color.green = png_get_uint_16(buf + 2);
+      png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
+   }
+
+   else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
+      {
+         /* TODO: is this actually an error in the ISO spec? */
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "out of place");
+         return;
+      }
+
+      if (length > (unsigned int) png_ptr->num_palette ||
+         length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
+         length == 0)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "invalid");
+         return;
+      }
+
+      png_crc_read(png_ptr, readbuf, length);
+      png_ptr->num_trans = (png_uint_16)length;
+   }
+
+   else
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid with alpha channel");
+      return;
+   }
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+   {
+      png_ptr->num_trans = 0;
+      return;
+   }
+
+   /* TODO: this is a horrible side effect in the palette case because the
+    * png_struct ends up with a pointer to the tRNS buffer owned by the
+    * png_info.  Fix this.
+    */
+   png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
+       &(png_ptr->trans_color));
+}
+#endif
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+void /* PRIVATE */
+png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   unsigned int truelen;
+   png_byte buf[6];
+   png_color_16 background;
+
+   png_debug(1, "in png_handle_bKGD");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
+       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+       (png_ptr->mode & PNG_HAVE_PLTE) == 0))
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      truelen = 1;
+
+   else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      truelen = 6;
+
+   else
+      truelen = 2;
+
+   if (length != truelen)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, truelen);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* We convert the index value into RGB components so that we can allow
+    * arbitrary RGB values for background when we have transparency, and
+    * so it is easy to determine the RGB values of the background color
+    * from the info_ptr struct.
+    */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      background.index = buf[0];
+
+      if (info_ptr != NULL && info_ptr->num_palette != 0)
+      {
+         if (buf[0] >= info_ptr->num_palette)
+         {
+            png_chunk_benign_error(png_ptr, "invalid index");
+            return;
+         }
+
+         background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
+         background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
+         background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
+      }
+
+      else
+         background.red = background.green = background.blue = 0;
+
+      background.gray = 0;
+   }
+
+   else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
+   {
+      if (png_ptr->bit_depth <= 8)
+      {
+         if (buf[0] != 0 || buf[1] >= (unsigned int)(1 << png_ptr->bit_depth))
+         {
+            png_chunk_benign_error(png_ptr, "invalid gray level");
+            return;
+         }
+      }
+
+      background.index = 0;
+      background.red =
+      background.green =
+      background.blue =
+      background.gray = png_get_uint_16(buf);
+   }
+
+   else
+   {
+      if (png_ptr->bit_depth <= 8)
+      {
+         if (buf[0] != 0 || buf[2] != 0 || buf[4] != 0)
+         {
+            png_chunk_benign_error(png_ptr, "invalid color");
+            return;
+         }
+      }
+
+      background.index = 0;
+      background.red = png_get_uint_16(buf);
+      background.green = png_get_uint_16(buf + 2);
+      background.blue = png_get_uint_16(buf + 4);
+      background.gray = 0;
+   }
+
+   png_set_bKGD(png_ptr, info_ptr, &background);
+}
+#endif
+
+#ifdef PNG_READ_eXIf_SUPPORTED
+void /* PRIVATE */
+png_handle_eXIf(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   unsigned int i;
+
+   png_debug(1, "in png_handle_eXIf");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   if (length < 2)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "too short");
+      return;
+   }
+
+   else if (info_ptr == NULL || (info_ptr->valid & PNG_INFO_eXIf) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   info_ptr->free_me |= PNG_FREE_EXIF;
+
+   info_ptr->eXIf_buf = png_voidcast(png_bytep,
+             png_malloc_warn(png_ptr, length));
+
+   if (info_ptr->eXIf_buf == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   for (i = 0; i < length; i++)
+   {
+      png_byte buf[1];
+      png_crc_read(png_ptr, buf, 1);
+      info_ptr->eXIf_buf[i] = buf[0];
+      if (i == 1)
+      {
+         if ((buf[0] != 'M' && buf[0] != 'I') ||
+             (info_ptr->eXIf_buf[0] != buf[0]))
+         {
+            png_crc_finish(png_ptr, length - 2);
+            png_chunk_benign_error(png_ptr, "incorrect byte-order specifier");
+            png_free(png_ptr, info_ptr->eXIf_buf);
+            info_ptr->eXIf_buf = NULL;
+            return;
+         }
+      }
+   }
+
+   if (png_crc_finish(png_ptr, 0) == 0)
+      png_set_eXIf_1(png_ptr, info_ptr, length, info_ptr->eXIf_buf);
+
+   png_free(png_ptr, info_ptr->eXIf_buf);
+   info_ptr->eXIf_buf = NULL;
+}
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+void /* PRIVATE */
+png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   unsigned int num, i;
+   png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
+
+   png_debug(1, "in png_handle_hIST");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
+       (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   num = length / 2 ;
+
+   if (length != num * 2 ||
+       num != (unsigned int)png_ptr->num_palette ||
+       num > (unsigned int)PNG_MAX_PALETTE_LENGTH)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   for (i = 0; i < num; i++)
+   {
+      png_byte buf[2];
+
+      png_crc_read(png_ptr, buf, 2);
+      readbuf[i] = png_get_uint_16(buf);
+   }
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   png_set_hIST(png_ptr, info_ptr, readbuf);
+}
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+void /* PRIVATE */
+png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[9];
+   png_uint_32 res_x, res_y;
+   int unit_type;
+
+   png_debug(1, "in png_handle_pHYs");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (length != 9)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 9);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   res_x = png_get_uint_32(buf);
+   res_y = png_get_uint_32(buf + 4);
+   unit_type = buf[8];
+   png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
+}
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+void /* PRIVATE */
+png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[9];
+   png_int_32 offset_x, offset_y;
+   int unit_type;
+
+   png_debug(1, "in png_handle_oFFs");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if (length != 9)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 9);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   offset_x = png_get_int_32(buf);
+   offset_y = png_get_int_32(buf + 4);
+   unit_type = buf[8];
+   png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
+}
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+/* Read the pCAL chunk (described in the PNG Extensions document) */
+void /* PRIVATE */
+png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_int_32 X0, X1;
+   png_byte type, nparams;
+   png_bytep buffer, buf, units, endptr;
+   png_charpp params;
+   int i;
+
+   png_debug(1, "in png_handle_pCAL");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
+       length + 1);
+
+   buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
+
+   if (buffer == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   buffer[length] = 0; /* Null terminate the last string */
+
+   png_debug(3, "Finding end of pCAL purpose string");
+   for (buf = buffer; *buf; buf++)
+      /* Empty loop */ ;
+
+   endptr = buffer + length;
+
+   /* We need to have at least 12 bytes after the purpose string
+    * in order to get the parameter information.
+    */
+   if (endptr - buf <= 12)
+   {
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
+   X0 = png_get_int_32((png_bytep)buf+1);
+   X1 = png_get_int_32((png_bytep)buf+5);
+   type = buf[9];
+   nparams = buf[10];
+   units = buf + 11;
+
+   png_debug(3, "Checking pCAL equation type and number of parameters");
+   /* Check that we have the right number of parameters for known
+    * equation types.
+    */
+   if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
+       (type == PNG_EQUATION_BASE_E && nparams != 3) ||
+       (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
+       (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
+   {
+      png_chunk_benign_error(png_ptr, "invalid parameter count");
+      return;
+   }
+
+   else if (type >= PNG_EQUATION_LAST)
+   {
+      png_chunk_benign_error(png_ptr, "unrecognized equation type");
+   }
+
+   for (buf = units; *buf; buf++)
+      /* Empty loop to move past the units string. */ ;
+
+   png_debug(3, "Allocating pCAL parameters array");
+
+   params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
+       nparams * (sizeof (png_charp))));
+
+   if (params == NULL)
+   {
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   /* Get pointers to the start of each parameter string. */
+   for (i = 0; i < nparams; i++)
+   {
+      buf++; /* Skip the null string terminator from previous parameter. */
+
+      png_debug1(3, "Reading pCAL parameter %d", i);
+
+      for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
+         /* Empty loop to move past each parameter string */ ;
+
+      /* Make sure we haven't run out of data yet */
+      if (buf > endptr)
+      {
+         png_free(png_ptr, params);
+         png_chunk_benign_error(png_ptr, "invalid data");
+         return;
+      }
+   }
+
+   png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
+       (png_charp)units, params);
+
+   png_free(png_ptr, params);
+}
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+/* Read the sCAL chunk */
+void /* PRIVATE */
+png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_bytep buffer;
+   size_t i;
+   int state;
+
+   png_debug(1, "in png_handle_sCAL");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of place");
+      return;
+   }
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   /* Need unit type, width, \0, height: minimum 4 bytes */
+   else if (length < 4)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
+       length + 1);
+
+   buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
+
+   if (buffer == NULL)
+   {
+      png_chunk_benign_error(png_ptr, "out of memory");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+   buffer[length] = 0; /* Null terminate the last string */
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* Validate the unit. */
+   if (buffer[0] != 1 && buffer[0] != 2)
+   {
+      png_chunk_benign_error(png_ptr, "invalid unit");
+      return;
+   }
+
+   /* Validate the ASCII numbers, need two ASCII numbers separated by
+    * a '\0' and they need to fit exactly in the chunk data.
+    */
+   i = 1;
+   state = 0;
+
+   if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
+       i >= length || buffer[i++] != 0)
+      png_chunk_benign_error(png_ptr, "bad width format");
+
+   else if (PNG_FP_IS_POSITIVE(state) == 0)
+      png_chunk_benign_error(png_ptr, "non-positive width");
+
+   else
+   {
+      size_t heighti = i;
+
+      state = 0;
+      if (png_check_fp_number((png_const_charp)buffer, length,
+          &state, &i) == 0 || i != length)
+         png_chunk_benign_error(png_ptr, "bad height format");
+
+      else if (PNG_FP_IS_POSITIVE(state) == 0)
+         png_chunk_benign_error(png_ptr, "non-positive height");
+
+      else
+         /* This is the (only) success case. */
+         png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
+             (png_charp)buffer+1, (png_charp)buffer+heighti);
+   }
+}
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+void /* PRIVATE */
+png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_byte buf[7];
+   png_time mod_time;
+
+   png_debug(1, "in png_handle_tIME");
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "duplicate");
+      return;
+   }
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+   if (length != 7)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "invalid");
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 7);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   mod_time.second = buf[6];
+   mod_time.minute = buf[5];
+   mod_time.hour = buf[4];
+   mod_time.day = buf[3];
+   mod_time.month = buf[2];
+   mod_time.year = png_get_uint_16(buf);
+
+   png_set_tIME(png_ptr, info_ptr, &mod_time);
+}
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_text  text_info;
+   png_bytep buffer;
+   png_charp key;
+   png_charp text;
+   png_uint_32 skip = 0;
+
+   png_debug(1, "in png_handle_tEXt");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "no space in chunk cache");
+         return;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (length > 65535U)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "too large to fit in memory");
+      return;
+   }
+#endif
+
+   buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
+
+   if (buffer == NULL)
+   {
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, skip) != 0)
+      return;
+
+   key = (png_charp)buffer;
+   key[length] = 0;
+
+   for (text = key; *text; text++)
+      /* Empty loop to find end of key */ ;
+
+   if (text != key + length)
+      text++;
+
+   text_info.compression = PNG_TEXT_COMPRESSION_NONE;
+   text_info.key = key;
+   text_info.lang = NULL;
+   text_info.lang_key = NULL;
+   text_info.itxt_length = 0;
+   text_info.text = text;
+   text_info.text_length = strlen(text);
+
+   if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
+      png_warning(png_ptr, "Insufficient memory to process text chunk");
+}
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+/* Note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_const_charp errmsg = NULL;
+   png_bytep       buffer;
+   png_uint_32     keyword_length;
+
+   png_debug(1, "in png_handle_zTXt");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "no space in chunk cache");
+         return;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+   /* Note, "length" is sufficient here; we won't be adding
+    * a null terminator later.
+    */
+   buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
+
+   if (buffer == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* TODO: also check that the keyword contents match the spec! */
+   for (keyword_length = 0;
+      keyword_length < length && buffer[keyword_length] != 0;
+      ++keyword_length)
+      /* Empty loop to find end of name */ ;
+
+   if (keyword_length > 79 || keyword_length < 1)
+      errmsg = "bad keyword";
+
+   /* zTXt must have some LZ data after the keyword, although it may expand to
+    * zero bytes; we need a '\0' at the end of the keyword, the compression type
+    * then the LZ data:
+    */
+   else if (keyword_length + 3 > length)
+      errmsg = "truncated";
+
+   else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
+      errmsg = "unknown compression type";
+
+   else
+   {
+      png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
+
+      /* TODO: at present png_decompress_chunk imposes a single application
+       * level memory limit, this should be split to different values for iCCP
+       * and text chunks.
+       */
+      if (png_decompress_chunk(png_ptr, length, keyword_length+2,
+          &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
+      {
+         png_text text;
+
+         if (png_ptr->read_buffer == NULL)
+           errmsg="Read failure in png_handle_zTXt";
+         else
+         {
+            /* It worked; png_ptr->read_buffer now looks like a tEXt chunk
+             * except for the extra compression type byte and the fact that
+             * it isn't necessarily '\0' terminated.
+             */
+            buffer = png_ptr->read_buffer;
+            buffer[uncompressed_length+(keyword_length+2)] = 0;
+
+            text.compression = PNG_TEXT_COMPRESSION_zTXt;
+            text.key = (png_charp)buffer;
+            text.text = (png_charp)(buffer + keyword_length+2);
+            text.text_length = uncompressed_length;
+            text.itxt_length = 0;
+            text.lang = NULL;
+            text.lang_key = NULL;
+
+            if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
+               errmsg = "insufficient memory";
+         }
+      }
+
+      else
+         errmsg = png_ptr->zstream.msg;
+   }
+
+   if (errmsg != NULL)
+      png_chunk_benign_error(png_ptr, errmsg);
+}
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+/* Note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+   png_const_charp errmsg = NULL;
+   png_bytep buffer;
+   png_uint_32 prefix_length;
+
+   png_debug(1, "in png_handle_iTXt");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_cache_max != 0)
+   {
+      if (png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+
+      if (--png_ptr->user_chunk_cache_max == 1)
+      {
+         png_crc_finish(png_ptr, length);
+         png_chunk_benign_error(png_ptr, "no space in chunk cache");
+         return;
+      }
+   }
+#endif
+
+   if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+      png_chunk_error(png_ptr, "missing IHDR");
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+   buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
+
+   if (buffer == NULL)
+   {
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "out of memory");
+      return;
+   }
+
+   png_crc_read(png_ptr, buffer, length);
+
+   if (png_crc_finish(png_ptr, 0) != 0)
+      return;
+
+   /* First the keyword. */
+   for (prefix_length=0;
+      prefix_length < length && buffer[prefix_length] != 0;
+      ++prefix_length)
+      /* Empty loop */ ;
+
+   /* Perform a basic check on the keyword length here. */
+   if (prefix_length > 79 || prefix_length < 1)
+      errmsg = "bad keyword";
+
+   /* Expect keyword, compression flag, compression type, language, translated
+    * keyword (both may be empty but are 0 terminated) then the text, which may
+    * be empty.
+    */
+   else if (prefix_length + 5 > length)
+      errmsg = "truncated";
+
+   else if (buffer[prefix_length+1] == 0 ||
+      (buffer[prefix_length+1] == 1 &&
+      buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
+   {
+      int compressed = buffer[prefix_length+1] != 0;
+      png_uint_32 language_offset, translated_keyword_offset;
+      png_alloc_size_t uncompressed_length = 0;
+
+      /* Now the language tag */
+      prefix_length += 3;
+      language_offset = prefix_length;
+
+      for (; prefix_length < length && buffer[prefix_length] != 0;
+         ++prefix_length)
+         /* Empty loop */ ;
+
+      /* WARNING: the length may be invalid here, this is checked below. */
+      translated_keyword_offset = ++prefix_length;
+
+      for (; prefix_length < length && buffer[prefix_length] != 0;
+         ++prefix_length)
+         /* Empty loop */ ;
+
+      /* prefix_length should now be at the trailing '\0' of the translated
+       * keyword, but it may already be over the end.  None of this arithmetic
+       * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
+       * systems the available allocation may overflow.
+       */
+      ++prefix_length;
+
+      if (compressed == 0 && prefix_length <= length)
+         uncompressed_length = length - prefix_length;
+
+      else if (compressed != 0 && prefix_length < length)
+      {
+         uncompressed_length = PNG_SIZE_MAX;
+
+         /* TODO: at present png_decompress_chunk imposes a single application
+          * level memory limit, this should be split to different values for
+          * iCCP and text chunks.
+          */
+         if (png_decompress_chunk(png_ptr, length, prefix_length,
+             &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
+            buffer = png_ptr->read_buffer;
+
+         else
+            errmsg = png_ptr->zstream.msg;
+      }
+
+      else
+         errmsg = "truncated";
+
+      if (errmsg == NULL)
+      {
+         png_text text;
+
+         buffer[uncompressed_length+prefix_length] = 0;
+
+         if (compressed == 0)
+            text.compression = PNG_ITXT_COMPRESSION_NONE;
+
+         else
+            text.compression = PNG_ITXT_COMPRESSION_zTXt;
+
+         text.key = (png_charp)buffer;
+         text.lang = (png_charp)buffer + language_offset;
+         text.lang_key = (png_charp)buffer + translated_keyword_offset;
+         text.text = (png_charp)buffer + prefix_length;
+         text.text_length = 0;
+         text.itxt_length = uncompressed_length;
+
+         if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
+            errmsg = "insufficient memory";
+      }
+   }
+
+   else
+      errmsg = "bad compression info";
+
+   if (errmsg != NULL)
+      png_chunk_benign_error(png_ptr, errmsg);
+}
+#endif
+
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+/* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
+static int
+png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
+{
+   png_alloc_size_t limit = PNG_SIZE_MAX;
+
+   if (png_ptr->unknown_chunk.data != NULL)
+   {
+      png_free(png_ptr, png_ptr->unknown_chunk.data);
+      png_ptr->unknown_chunk.data = NULL;
+   }
+
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_malloc_max > 0 &&
+       png_ptr->user_chunk_malloc_max < limit)
+      limit = png_ptr->user_chunk_malloc_max;
+
+#  elif PNG_USER_CHUNK_MALLOC_MAX > 0
+   if (PNG_USER_CHUNK_MALLOC_MAX < limit)
+      limit = PNG_USER_CHUNK_MALLOC_MAX;
+#  endif
+
+   if (length <= limit)
+   {
+      PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
+      /* The following is safe because of the PNG_SIZE_MAX init above */
+      png_ptr->unknown_chunk.size = (size_t)length/*SAFE*/;
+      /* 'mode' is a flag array, only the bottom four bits matter here */
+      png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
+
+      if (length == 0)
+         png_ptr->unknown_chunk.data = NULL;
+
+      else
+      {
+         /* Do a 'warn' here - it is handled below. */
+         png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
+             png_malloc_warn(png_ptr, length));
+      }
+   }
+
+   if (png_ptr->unknown_chunk.data == NULL && length > 0)
+   {
+      /* This is benign because we clean up correctly */
+      png_crc_finish(png_ptr, length);
+      png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
+      return 0;
+   }
+
+   else
+   {
+      if (length > 0)
+         png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
+      png_crc_finish(png_ptr, 0);
+      return 1;
+   }
+}
+#endif /* READ_UNKNOWN_CHUNKS */
+
+/* Handle an unknown, or known but disabled, chunk */
+void /* PRIVATE */
+png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
+    png_uint_32 length, int keep)
+{
+   int handled = 0; /* the chunk was handled */
+
+   png_debug(1, "in png_handle_unknown");
+
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+   /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
+    * the bug which meant that setting a non-default behavior for a specific
+    * chunk would be ignored (the default was always used unless a user
+    * callback was installed).
+    *
+    * 'keep' is the value from the png_chunk_unknown_handling, the setting for
+    * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
+    * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
+    * This is just an optimization to avoid multiple calls to the lookup
+    * function.
+    */
+#  ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#     ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
+#     endif
+#  endif
+
+   /* One of the following methods will read the chunk or skip it (at least one
+    * of these is always defined because this is the only way to switch on
+    * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+    */
+#  ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   /* The user callback takes precedence over the chunk keep value, but the
+    * keep value is still required to validate a save of a critical chunk.
+    */
+   if (png_ptr->read_user_chunk_fn != NULL)
+   {
+      if (png_cache_unknown_chunk(png_ptr, length) != 0)
+      {
+         /* Callback to user unknown chunk handler */
+         int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
+             &png_ptr->unknown_chunk);
+
+         /* ret is:
+          * negative: An error occurred; png_chunk_error will be called.
+          *     zero: The chunk was not handled, the chunk will be discarded
+          *           unless png_set_keep_unknown_chunks has been used to set
+          *           a 'keep' behavior for this particular chunk, in which
+          *           case that will be used.  A critical chunk will cause an
+          *           error at this point unless it is to be saved.
+          * positive: The chunk was handled, libpng will ignore/discard it.
+          */
+         if (ret < 0)
+            png_chunk_error(png_ptr, "error in user chunk");
+
+         else if (ret == 0)
+         {
+            /* If the keep value is 'default' or 'never' override it, but
+             * still error out on critical chunks unless the keep value is
+             * 'always'  While this is weird it is the behavior in 1.4.12.
+             * A possible improvement would be to obey the value set for the
+             * chunk, but this would be an API change that would probably
+             * damage some applications.
+             *
+             * The png_app_warning below catches the case that matters, where
+             * the application has not set specific save or ignore for this
+             * chunk or global save or ignore.
+             */
+            if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
+            {
+#              ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+               if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
+               {
+                  png_chunk_warning(png_ptr, "Saving unknown chunk:");
+                  png_app_warning(png_ptr,
+                      "forcing save of an unhandled chunk;"
+                      " please call png_set_keep_unknown_chunks");
+                      /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
+               }
+#              endif
+               keep = PNG_HANDLE_CHUNK_IF_SAFE;
+            }
+         }
+
+         else /* chunk was handled */
+         {
+            handled = 1;
+            /* Critical chunks can be safely discarded at this point. */
+            keep = PNG_HANDLE_CHUNK_NEVER;
+         }
+      }
+
+      else
+         keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
+   }
+
+   else
+   /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
+#  endif /* READ_USER_CHUNKS */
+
+#  ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+   {
+      /* keep is currently just the per-chunk setting, if there was no
+       * setting change it to the global default now (not that this may
+       * still be AS_DEFAULT) then obtain the cache of the chunk if required,
+       * if not simply skip the chunk.
+       */
+      if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+         keep = png_ptr->unknown_default;
+
+      if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
+         (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
+          PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
+      {
+         if (png_cache_unknown_chunk(png_ptr, length) == 0)
+            keep = PNG_HANDLE_CHUNK_NEVER;
+      }
+
+      else
+         png_crc_finish(png_ptr, length);
+   }
+#  else
+#     ifndef PNG_READ_USER_CHUNKS_SUPPORTED
+#        error no method to support READ_UNKNOWN_CHUNKS
+#     endif
+
+   {
+      /* If here there is no read callback pointer set and no support is
+       * compiled in to just save the unknown chunks, so simply skip this
+       * chunk.  If 'keep' is something other than AS_DEFAULT or NEVER then
+       * the app has erroneously asked for unknown chunk saving when there
+       * is no support.
+       */
+      if (keep > PNG_HANDLE_CHUNK_NEVER)
+         png_app_error(png_ptr, "no unknown chunk support available");
+
+      png_crc_finish(png_ptr, length);
+   }
+#  endif
+
+#  ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+   /* Now store the chunk in the chunk list if appropriate, and if the limits
+    * permit it.
+    */
+   if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
+      (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
+       PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
+   {
+#     ifdef PNG_USER_LIMITS_SUPPORTED
+      switch (png_ptr->user_chunk_cache_max)
+      {
+         case 2:
+            png_ptr->user_chunk_cache_max = 1;
+            png_chunk_benign_error(png_ptr, "no space in chunk cache");
+            /* FALLTHROUGH */
+         case 1:
+            /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
+             * chunk being skipped, now there will be a hard error below.
+             */
+            break;
+
+         default: /* not at limit */
+            --(png_ptr->user_chunk_cache_max);
+            /* FALLTHROUGH */
+         case 0: /* no limit */
+#  endif /* USER_LIMITS */
+            /* Here when the limit isn't reached or when limits are compiled
+             * out; store the chunk.
+             */
+            png_set_unknown_chunks(png_ptr, info_ptr,
+                &png_ptr->unknown_chunk, 1);
+            handled = 1;
+#  ifdef PNG_USER_LIMITS_SUPPORTED
+            break;
+      }
+#  endif
+   }
+#  else /* no store support: the chunk must be handled by the user callback */
+   PNG_UNUSED(info_ptr)
+#  endif
+
+   /* Regardless of the error handling below the cached data (if any) can be
+    * freed now.  Notice that the data is not freed if there is a png_error, but
+    * it will be freed by destroy_read_struct.
+    */
+   if (png_ptr->unknown_chunk.data != NULL)
+      png_free(png_ptr, png_ptr->unknown_chunk.data);
+   png_ptr->unknown_chunk.data = NULL;
+
+#else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
+   /* There is no support to read an unknown chunk, so just skip it. */
+   png_crc_finish(png_ptr, length);
+   PNG_UNUSED(info_ptr)
+   PNG_UNUSED(keep)
+#endif /* !READ_UNKNOWN_CHUNKS */
+
+   /* Check for unhandled critical chunks */
+   if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
+      png_chunk_error(png_ptr, "unhandled critical chunk");
+}
+
+/* This function is called to verify that a chunk name is valid.
+ * This function can't have the "critical chunk check" incorporated
+ * into it, since in the future we will need to be able to call user
+ * functions to handle unknown critical chunks after we check that
+ * the chunk name itself is valid.
+ */
+
+/* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
+ *
+ * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+ */
+
+void /* PRIVATE */
+png_check_chunk_name(png_const_structrp png_ptr, png_uint_32 chunk_name)
+{
+   int i;
+   png_uint_32 cn=chunk_name;
+
+   png_debug(1, "in png_check_chunk_name");
+
+   for (i=1; i<=4; ++i)
+   {
+      int c = cn & 0xff;
+
+      if (c < 65 || c > 122 || (c > 90 && c < 97))
+         png_chunk_error(png_ptr, "invalid chunk type");
+
+      cn >>= 8;
+   }
+}
+
+void /* PRIVATE */
+png_check_chunk_length(png_const_structrp png_ptr, png_uint_32 length)
+{
+   png_alloc_size_t limit = PNG_UINT_31_MAX;
+
+# ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_malloc_max > 0 &&
+       png_ptr->user_chunk_malloc_max < limit)
+      limit = png_ptr->user_chunk_malloc_max;
+# elif PNG_USER_CHUNK_MALLOC_MAX > 0
+   if (PNG_USER_CHUNK_MALLOC_MAX < limit)
+      limit = PNG_USER_CHUNK_MALLOC_MAX;
+# endif
+   if (png_ptr->chunk_name == png_IDAT)
+   {
+      png_alloc_size_t idat_limit = PNG_UINT_31_MAX;
+      size_t row_factor =
+         (size_t)png_ptr->width
+         * (size_t)png_ptr->channels
+         * (png_ptr->bit_depth > 8? 2: 1)
+         + 1
+         + (png_ptr->interlaced? 6: 0);
+      if (png_ptr->height > PNG_UINT_32_MAX/row_factor)
+         idat_limit = PNG_UINT_31_MAX;
+      else
+         idat_limit = png_ptr->height * row_factor;
+      row_factor = row_factor > 32566? 32566 : row_factor;
+      idat_limit += 6 + 5*(idat_limit/row_factor+1); /* zlib+deflate overhead */
+      idat_limit=idat_limit < PNG_UINT_31_MAX? idat_limit : PNG_UINT_31_MAX;
+      limit = limit < idat_limit? idat_limit : limit;
+   }
+
+   if (length > limit)
+   {
+      png_debug2(0," length = %lu, limit = %lu",
+         (unsigned long)length,(unsigned long)limit);
+      png_benign_error(png_ptr, "chunk data is too large");
+   }
+}
+
+/* Combines the row recently read in with the existing pixels in the row.  This
+ * routine takes care of alpha and transparency if requested.  This routine also
+ * handles the two methods of progressive display of interlaced images,
+ * depending on the 'display' value; if 'display' is true then the whole row
+ * (dp) is filled from the start by replicating the available pixels.  If
+ * 'display' is false only those pixels present in the pass are filled in.
+ */
+void /* PRIVATE */
+png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
+{
+   unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
+   png_const_bytep sp = png_ptr->row_buf + 1;
+   png_alloc_size_t row_width = png_ptr->width;
+   unsigned int pass = png_ptr->pass;
+   png_bytep end_ptr = 0;
+   png_byte end_byte = 0;
+   unsigned int end_mask;
+
+   png_debug(1, "in png_combine_row");
+
+   /* Added in 1.5.6: it should not be possible to enter this routine until at
+    * least one row has been read from the PNG data and transformed.
+    */
+   if (pixel_depth == 0)
+      png_error(png_ptr, "internal row logic error");
+
+   /* Added in 1.5.4: the pixel depth should match the information returned by
+    * any call to png_read_update_info at this point.  Do not continue if we got
+    * this wrong.
+    */
+   if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
+          PNG_ROWBYTES(pixel_depth, row_width))
+      png_error(png_ptr, "internal row size calculation error");
+
+   /* Don't expect this to ever happen: */
+   if (row_width == 0)
+      png_error(png_ptr, "internal row width error");
+
+   /* Preserve the last byte in cases where only part of it will be overwritten,
+    * the multiply below may overflow, we don't care because ANSI-C guarantees
+    * we get the low bits.
+    */
+   end_mask = (pixel_depth * row_width) & 7;
+   if (end_mask != 0)
+   {
+      /* end_ptr == NULL is a flag to say do nothing */
+      end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
+      end_byte = *end_ptr;
+#     ifdef PNG_READ_PACKSWAP_SUPPORTED
+      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+         /* little-endian byte */
+         end_mask = (unsigned int)(0xff << end_mask);
+
+      else /* big-endian byte */
+#     endif
+      end_mask = 0xff >> end_mask;
+      /* end_mask is now the bits to *keep* from the destination row */
+   }
+
+   /* For non-interlaced images this reduces to a memcpy(). A memcpy()
+    * will also happen if interlacing isn't supported or if the application
+    * does not call png_set_interlace_handling().  In the latter cases the
+    * caller just gets a sequence of the unexpanded rows from each interlace
+    * pass.
+    */
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0 &&
+       pass < 6 && (display == 0 ||
+       /* The following copies everything for 'display' on passes 0, 2 and 4. */
+       (display == 1 && (pass & 1) != 0)))
+   {
+      /* Narrow images may have no bits in a pass; the caller should handle
+       * this, but this test is cheap:
+       */
+      if (row_width <= PNG_PASS_START_COL(pass))
+         return;
+
+      if (pixel_depth < 8)
+      {
+         /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
+          * into 32 bits, then a single loop over the bytes using the four byte
+          * values in the 32-bit mask can be used.  For the 'display' option the
+          * expanded mask may also not require any masking within a byte.  To
+          * make this work the PACKSWAP option must be taken into account - it
+          * simply requires the pixels to be reversed in each byte.
+          *
+          * The 'regular' case requires a mask for each of the first 6 passes,
+          * the 'display' case does a copy for the even passes in the range
+          * 0..6.  This has already been handled in the test above.
+          *
+          * The masks are arranged as four bytes with the first byte to use in
+          * the lowest bits (little-endian) regardless of the order (PACKSWAP or
+          * not) of the pixels in each byte.
+          *
+          * NOTE: the whole of this logic depends on the caller of this function
+          * only calling it on rows appropriate to the pass.  This function only
+          * understands the 'x' logic; the 'y' logic is handled by the caller.
+          *
+          * The following defines allow generation of compile time constant bit
+          * masks for each pixel depth and each possibility of swapped or not
+          * swapped bytes.  Pass 'p' is in the range 0..6; 'x', a pixel index,
+          * is in the range 0..7; and the result is 1 if the pixel is to be
+          * copied in the pass, 0 if not.  'S' is for the sparkle method, 'B'
+          * for the block method.
+          *
+          * With some compilers a compile time expression of the general form:
+          *
+          *    (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
+          *
+          * Produces warnings with values of 'shift' in the range 33 to 63
+          * because the right hand side of the ?: expression is evaluated by
+          * the compiler even though it isn't used.  Microsoft Visual C (various
+          * versions) and the Intel C compiler are known to do this.  To avoid
+          * this the following macros are used in 1.5.6.  This is a temporary
+          * solution to avoid destabilizing the code during the release process.
+          */
+#        if PNG_USE_COMPILE_TIME_MASKS
+#           define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
+#           define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
+#        else
+#           define PNG_LSR(x,s) ((x)>>(s))
+#           define PNG_LSL(x,s) ((x)<<(s))
+#        endif
+#        define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
+           PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
+#        define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
+           PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
+
+         /* Return a mask for pass 'p' pixel 'x' at depth 'd'.  The mask is
+          * little endian - the first pixel is at bit 0 - however the extra
+          * parameter 's' can be set to cause the mask position to be swapped
+          * within each byte, to match the PNG format.  This is done by XOR of
+          * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
+          */
+#        define PIXEL_MASK(p,x,d,s) \
+            (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
+
+         /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
+          */
+#        define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
+#        define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
+
+         /* Combine 8 of these to get the full mask.  For the 1-bpp and 2-bpp
+          * cases the result needs replicating, for the 4-bpp case the above
+          * generates a full 32 bits.
+          */
+#        define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
+
+#        define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
+            S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
+            S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
+
+#        define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
+            B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
+            B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
+
+#if PNG_USE_COMPILE_TIME_MASKS
+         /* Utility macros to construct all the masks for a depth/swap
+          * combination.  The 's' parameter says whether the format is PNG
+          * (big endian bytes) or not.  Only the three odd-numbered passes are
+          * required for the display/block algorithm.
+          */
+#        define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
+            S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
+
+#        define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
+
+#        define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
+
+         /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
+          * then pass:
+          */
+         static const png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
+         {
+            /* Little-endian byte masks for PACKSWAP */
+            { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
+            /* Normal (big-endian byte) masks - PNG format */
+            { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
+         };
+
+         /* display_mask has only three entries for the odd passes, so index by
+          * pass>>1.
+          */
+         static const png_uint_32 display_mask[2][3][3] =
+         {
+            /* Little-endian byte masks for PACKSWAP */
+            { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
+            /* Normal (big-endian byte) masks - PNG format */
+            { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
+         };
+
+#        define MASK(pass,depth,display,png)\
+            ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
+               row_mask[png][DEPTH_INDEX(depth)][pass])
+
+#else /* !PNG_USE_COMPILE_TIME_MASKS */
+         /* This is the runtime alternative: it seems unlikely that this will
+          * ever be either smaller or faster than the compile time approach.
+          */
+#        define MASK(pass,depth,display,png)\
+            ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
+#endif /* !USE_COMPILE_TIME_MASKS */
+
+         /* Use the appropriate mask to copy the required bits.  In some cases
+          * the byte mask will be 0 or 0xff; optimize these cases.  row_width is
+          * the number of pixels, but the code copies bytes, so it is necessary
+          * to special case the end.
+          */
+         png_uint_32 pixels_per_byte = 8 / pixel_depth;
+         png_uint_32 mask;
+
+#        ifdef PNG_READ_PACKSWAP_SUPPORTED
+         if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+            mask = MASK(pass, pixel_depth, display, 0);
+
+         else
+#        endif
+         mask = MASK(pass, pixel_depth, display, 1);
+
+         for (;;)
+         {
+            png_uint_32 m;
+
+            /* It doesn't matter in the following if png_uint_32 has more than
+             * 32 bits because the high bits always match those in m<<24; it is,
+             * however, essential to use OR here, not +, because of this.
+             */
+            m = mask;
+            mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
+            m &= 0xff;
+
+            if (m != 0) /* something to copy */
+            {
+               if (m != 0xff)
+                  *dp = (png_byte)((*dp & ~m) | (*sp & m));
+               else
+                  *dp = *sp;
+            }
+
+            /* NOTE: this may overwrite the last byte with garbage if the image
+             * is not an exact number of bytes wide; libpng has always done
+             * this.
+             */
+            if (row_width <= pixels_per_byte)
+               break; /* May need to restore part of the last byte */
+
+            row_width -= pixels_per_byte;
+            ++dp;
+            ++sp;
+         }
+      }
+
+      else /* pixel_depth >= 8 */
+      {
+         unsigned int bytes_to_copy, bytes_to_jump;
+
+         /* Validate the depth - it must be a multiple of 8 */
+         if (pixel_depth & 7)
+            png_error(png_ptr, "invalid user transform pixel depth");
+
+         pixel_depth >>= 3; /* now in bytes */
+         row_width *= pixel_depth;
+
+         /* Regardless of pass number the Adam 7 interlace always results in a
+          * fixed number of pixels to copy then to skip.  There may be a
+          * different number of pixels to skip at the start though.
+          */
+         {
+            unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
+
+            row_width -= offset;
+            dp += offset;
+            sp += offset;
+         }
+
+         /* Work out the bytes to copy. */
+         if (display != 0)
+         {
+            /* When doing the 'block' algorithm the pixel in the pass gets
+             * replicated to adjacent pixels.  This is why the even (0,2,4,6)
+             * passes are skipped above - the entire expanded row is copied.
+             */
+            bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
+
+            /* But don't allow this number to exceed the actual row width. */
+            if (bytes_to_copy > row_width)
+               bytes_to_copy = (unsigned int)/*SAFE*/row_width;
+         }
+
+         else /* normal row; Adam7 only ever gives us one pixel to copy. */
+            bytes_to_copy = pixel_depth;
+
+         /* In Adam7 there is a constant offset between where the pixels go. */
+         bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
+
+         /* And simply copy these bytes.  Some optimization is possible here,
+          * depending on the value of 'bytes_to_copy'.  Special case the low
+          * byte counts, which we know to be frequent.
+          *
+          * Notice that these cases all 'return' rather than 'break' - this
+          * avoids an unnecessary test on whether to restore the last byte
+          * below.
+          */
+         switch (bytes_to_copy)
+         {
+            case 1:
+               for (;;)
+               {
+                  *dp = *sp;
+
+                  if (row_width <= bytes_to_jump)
+                     return;
+
+                  dp += bytes_to_jump;
+                  sp += bytes_to_jump;
+                  row_width -= bytes_to_jump;
+               }
+
+            case 2:
+               /* There is a possibility of a partial copy at the end here; this
+                * slows the code down somewhat.
+                */
+               do
+               {
+                  dp[0] = sp[0]; dp[1] = sp[1];
+
+                  if (row_width <= bytes_to_jump)
+                     return;
+
+                  sp += bytes_to_jump;
+                  dp += bytes_to_jump;
+                  row_width -= bytes_to_jump;
+               }
+               while (row_width > 1);
+
+               /* And there can only be one byte left at this point: */
+               *dp = *sp;
+               return;
+
+            case 3:
+               /* This can only be the RGB case, so each copy is exactly one
+                * pixel and it is not necessary to check for a partial copy.
+                */
+               for (;;)
+               {
+                  dp[0] = sp[0]; dp[1] = sp[1]; dp[2] = sp[2];
+
+                  if (row_width <= bytes_to_jump)
+                     return;
+
+                  sp += bytes_to_jump;
+                  dp += bytes_to_jump;
+                  row_width -= bytes_to_jump;
+               }
+
+            default:
+#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
+               /* Check for double byte alignment and, if possible, use a
+                * 16-bit copy.  Don't attempt this for narrow images - ones that
+                * are less than an interlace panel wide.  Don't attempt it for
+                * wide bytes_to_copy either - use the memcpy there.
+                */
+               if (bytes_to_copy < 16 /*else use memcpy*/ &&
+                   png_isaligned(dp, png_uint_16) &&
+                   png_isaligned(sp, png_uint_16) &&
+                   bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
+                   bytes_to_jump % (sizeof (png_uint_16)) == 0)
+               {
+                  /* Everything is aligned for png_uint_16 copies, but try for
+                   * png_uint_32 first.
+                   */
+                  if (png_isaligned(dp, png_uint_32) &&
+                      png_isaligned(sp, png_uint_32) &&
+                      bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
+                      bytes_to_jump % (sizeof (png_uint_32)) == 0)
+                  {
+                     png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
+                     png_const_uint_32p sp32 = png_aligncastconst(
+                         png_const_uint_32p, sp);
+                     size_t skip = (bytes_to_jump-bytes_to_copy) /
+                         (sizeof (png_uint_32));
+
+                     do
+                     {
+                        size_t c = bytes_to_copy;
+                        do
+                        {
+                           *dp32++ = *sp32++;
+                           c -= (sizeof (png_uint_32));
+                        }
+                        while (c > 0);
+
+                        if (row_width <= bytes_to_jump)
+                           return;
+
+                        dp32 += skip;
+                        sp32 += skip;
+                        row_width -= bytes_to_jump;
+                     }
+                     while (bytes_to_copy <= row_width);
+
+                     /* Get to here when the row_width truncates the final copy.
+                      * There will be 1-3 bytes left to copy, so don't try the
+                      * 16-bit loop below.
+                      */
+                     dp = (png_bytep)dp32;
+                     sp = (png_const_bytep)sp32;
+                     do
+                        *dp++ = *sp++;
+                     while (--row_width > 0);
+                     return;
+                  }
+
+                  /* Else do it in 16-bit quantities, but only if the size is
+                   * not too large.
+                   */
+                  else
+                  {
+                     png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
+                     png_const_uint_16p sp16 = png_aligncastconst(
+                        png_const_uint_16p, sp);
+                     size_t skip = (bytes_to_jump-bytes_to_copy) /
+                        (sizeof (png_uint_16));
+
+                     do
+                     {
+                        size_t c = bytes_to_copy;
+                        do
+                        {
+                           *dp16++ = *sp16++;
+                           c -= (sizeof (png_uint_16));
+                        }
+                        while (c > 0);
+
+                        if (row_width <= bytes_to_jump)
+                           return;
+
+                        dp16 += skip;
+                        sp16 += skip;
+                        row_width -= bytes_to_jump;
+                     }
+                     while (bytes_to_copy <= row_width);
+
+                     /* End of row - 1 byte left, bytes_to_copy > row_width: */
+                     dp = (png_bytep)dp16;
+                     sp = (png_const_bytep)sp16;
+                     do
+                        *dp++ = *sp++;
+                     while (--row_width > 0);
+                     return;
+                  }
+               }
+#endif /* ALIGN_TYPE code */
+
+               /* The true default - use a memcpy: */
+               for (;;)
+               {
+                  memcpy(dp, sp, bytes_to_copy);
+
+                  if (row_width <= bytes_to_jump)
+                     return;
+
+                  sp += bytes_to_jump;
+                  dp += bytes_to_jump;
+                  row_width -= bytes_to_jump;
+                  if (bytes_to_copy > row_width)
+                     bytes_to_copy = (unsigned int)/*SAFE*/row_width;
+               }
+         }
+
+         /* NOT REACHED*/
+      } /* pixel_depth >= 8 */
+
+      /* Here if pixel_depth < 8 to check 'end_ptr' below. */
+   }
+   else
+#endif /* READ_INTERLACING */
+
+   /* If here then the switch above wasn't used so just memcpy the whole row
+    * from the temporary row buffer (notice that this overwrites the end of the
+    * destination row if it is a partial byte.)
+    */
+   memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
+
+   /* Restore the overwritten bits from the last byte if necessary. */
+   if (end_ptr != NULL)
+      *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
+}
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+void /* PRIVATE */
+png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
+    png_uint_32 transformations /* Because these may affect the byte layout */)
+{
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Offset to next interlace block */
+   static const unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   png_debug(1, "in png_do_read_interlace");
+   if (row != NULL && row_info != NULL)
+   {
+      png_uint_32 final_width;
+
+      final_width = row_info->width * png_pass_inc[pass];
+
+      switch (row_info->pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp = row + (size_t)((row_info->width - 1) >> 3);
+            png_bytep dp = row + (size_t)((final_width - 1) >> 3);
+            unsigned int sshift, dshift;
+            unsigned int s_start, s_end;
+            int s_inc;
+            int jstop = (int)png_pass_inc[pass];
+            png_byte v;
+            png_uint_32 i;
+            int j;
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+            if ((transformations & PNG_PACKSWAP) != 0)
+            {
+                sshift = ((row_info->width + 7) & 0x07);
+                dshift = ((final_width + 7) & 0x07);
+                s_start = 7;
+                s_end = 0;
+                s_inc = -1;
+            }
+
+            else
+#endif
+            {
+                sshift = 7 - ((row_info->width + 7) & 0x07);
+                dshift = 7 - ((final_width + 7) & 0x07);
+                s_start = 0;
+                s_end = 7;
+                s_inc = 1;
+            }
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               v = (png_byte)((*sp >> sshift) & 0x01);
+               for (j = 0; j < jstop; j++)
+               {
+                  unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
+                  tmp |= (unsigned int)(v << dshift);
+                  *dp = (png_byte)(tmp & 0xff);
+
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+
+                  else
+                     dshift = (unsigned int)((int)dshift + s_inc);
+               }
+
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+
+               else
+                  sshift = (unsigned int)((int)sshift + s_inc);
+            }
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
+            png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
+            unsigned int sshift, dshift;
+            unsigned int s_start, s_end;
+            int s_inc;
+            int jstop = (int)png_pass_inc[pass];
+            png_uint_32 i;
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+            if ((transformations & PNG_PACKSWAP) != 0)
+            {
+               sshift = (((row_info->width + 3) & 0x03) << 1);
+               dshift = (((final_width + 3) & 0x03) << 1);
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+
+            else
+#endif
+            {
+               sshift = ((3 - ((row_info->width + 3) & 0x03)) << 1);
+               dshift = ((3 - ((final_width + 3) & 0x03)) << 1);
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               png_byte v;
+               int j;
+
+               v = (png_byte)((*sp >> sshift) & 0x03);
+               for (j = 0; j < jstop; j++)
+               {
+                  unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
+                  tmp |= (unsigned int)(v << dshift);
+                  *dp = (png_byte)(tmp & 0xff);
+
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+
+                  else
+                     dshift = (unsigned int)((int)dshift + s_inc);
+               }
+
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+
+               else
+                  sshift = (unsigned int)((int)sshift + s_inc);
+            }
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp = row + (size_t)((row_info->width - 1) >> 1);
+            png_bytep dp = row + (size_t)((final_width - 1) >> 1);
+            unsigned int sshift, dshift;
+            unsigned int s_start, s_end;
+            int s_inc;
+            png_uint_32 i;
+            int jstop = (int)png_pass_inc[pass];
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+            if ((transformations & PNG_PACKSWAP) != 0)
+            {
+               sshift = (((row_info->width + 1) & 0x01) << 2);
+               dshift = (((final_width + 1) & 0x01) << 2);
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+
+            else
+#endif
+            {
+               sshift = ((1 - ((row_info->width + 1) & 0x01)) << 2);
+               dshift = ((1 - ((final_width + 1) & 0x01)) << 2);
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
+               int j;
+
+               for (j = 0; j < jstop; j++)
+               {
+                  unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
+                  tmp |= (unsigned int)(v << dshift);
+                  *dp = (png_byte)(tmp & 0xff);
+
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+
+                  else
+                     dshift = (unsigned int)((int)dshift + s_inc);
+               }
+
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+
+               else
+                  sshift = (unsigned int)((int)sshift + s_inc);
+            }
+            break;
+         }
+
+         default:
+         {
+            size_t pixel_bytes = (row_info->pixel_depth >> 3);
+
+            png_bytep sp = row + (size_t)(row_info->width - 1)
+                * pixel_bytes;
+
+            png_bytep dp = row + (size_t)(final_width - 1) * pixel_bytes;
+
+            int jstop = (int)png_pass_inc[pass];
+            png_uint_32 i;
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
+               int j;
+
+               memcpy(v, sp, pixel_bytes);
+
+               for (j = 0; j < jstop; j++)
+               {
+                  memcpy(dp, v, pixel_bytes);
+                  dp -= pixel_bytes;
+               }
+
+               sp -= pixel_bytes;
+            }
+            break;
+         }
+      }
+
+      row_info->width = final_width;
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
+   }
+#ifndef PNG_READ_PACKSWAP_SUPPORTED
+   PNG_UNUSED(transformations)  /* Silence compiler warning */
+#endif
+}
+#endif /* READ_INTERLACING */
+
+static void
+png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t i;
+   size_t istop = row_info->rowbytes;
+   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+   png_bytep rp = row + bpp;
+
+   PNG_UNUSED(prev_row)
+
+   for (i = bpp; i < istop; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+      rp++;
+   }
+}
+
+static void
+png_read_filter_row_up(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t i;
+   size_t istop = row_info->rowbytes;
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+
+   for (i = 0; i < istop; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+      rp++;
+   }
+}
+
+static void
+png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   size_t i;
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+   size_t istop = row_info->rowbytes - bpp;
+
+   for (i = 0; i < bpp; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) +
+         ((int)(*pp++) / 2 )) & 0xff);
+
+      rp++;
+   }
+
+   for (i = 0; i < istop; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) +
+         (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+      rp++;
+   }
+}
+
+static void
+png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   png_bytep rp_end = row + row_info->rowbytes;
+   int a, c;
+
+   /* First pixel/byte */
+   c = *prev_row++;
+   a = *row + c;
+   *row++ = (png_byte)a;
+
+   /* Remainder */
+   while (row < rp_end)
+   {
+      int b, pa, pb, pc, p;
+
+      a &= 0xff; /* From previous iteration or start */
+      b = *prev_row++;
+
+      p = b - c;
+      pc = a - c;
+
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+      /* Find the best predictor, the least of pa, pb, pc favoring the earlier
+       * ones in the case of a tie.
+       */
+      if (pb < pa)
+      {
+         pa = pb; a = b;
+      }
+      if (pc < pa) a = c;
+
+      /* Calculate the current pixel in a, and move the previous row pixel to c
+       * for the next time round the loop
+       */
+      c = b;
+      a += *row;
+      *row++ = (png_byte)a;
+   }
+}
+
+static void
+png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row)
+{
+   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+   png_bytep rp_end = row + bpp;
+
+   /* Process the first pixel in the row completely (this is the same as 'up'
+    * because there is only one candidate predictor for the first row).
+    */
+   while (row < rp_end)
+   {
+      int a = *row + *prev_row++;
+      *row++ = (png_byte)a;
+   }
+
+   /* Remainder */
+   rp_end = rp_end + (row_info->rowbytes - bpp);
+
+   while (row < rp_end)
+   {
+      int a, b, c, pa, pb, pc, p;
+
+      c = *(prev_row - bpp);
+      a = *(row - bpp);
+      b = *prev_row++;
+
+      p = b - c;
+      pc = a - c;
+
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+      if (pb < pa)
+      {
+         pa = pb; a = b;
+      }
+      if (pc < pa) a = c;
+
+      a += *row;
+      *row++ = (png_byte)a;
+   }
+}
+
+static void
+png_init_filter_functions(png_structrp pp)
+   /* This function is called once for every PNG image (except for PNG images
+    * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
+    * implementations required to reverse the filtering of PNG rows.  Reversing
+    * the filter is the first transformation performed on the row data.  It is
+    * performed in place, therefore an implementation can be selected based on
+    * the image pixel format.  If the implementation depends on image width then
+    * take care to ensure that it works correctly if the image is interlaced -
+    * interlacing causes the actual row width to vary.
+    */
+{
+   unsigned int bpp = (pp->pixel_depth + 7) >> 3;
+
+   pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
+   pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
+   if (bpp == 1)
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth_1byte_pixel;
+   else
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+         png_read_filter_row_paeth_multibyte_pixel;
+
+#ifdef PNG_FILTER_OPTIMIZATIONS
+   /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
+    * call to install hardware optimizations for the above functions; simply
+    * replace whatever elements of the pp->read_filter[] array with a hardware
+    * specific (or, for that matter, generic) optimization.
+    *
+    * To see an example of this examine what configure.ac does when
+    * --enable-arm-neon is specified on the command line.
+    */
+   PNG_FILTER_OPTIMIZATIONS(pp, bpp);
+#endif
+}
+
+void /* PRIVATE */
+png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
+    png_const_bytep prev_row, int filter)
+{
+   /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
+    * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
+    * implementations.  See png_init_filter_functions above.
+    */
+   if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
+   {
+      if (pp->read_filter[0] == NULL)
+         png_init_filter_functions(pp);
+
+      pp->read_filter[filter-1](row_info, row, prev_row);
+   }
+}
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+void /* PRIVATE */
+png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
+    png_alloc_size_t avail_out)
+{
+   /* Loop reading IDATs and decompressing the result into output[avail_out] */
+   png_ptr->zstream.next_out = output;
+   png_ptr->zstream.avail_out = 0; /* safety: set below */
+
+   if (output == NULL)
+      avail_out = 0;
+
+   do
+   {
+      int ret;
+      png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
+
+      if (png_ptr->zstream.avail_in == 0)
+      {
+         uInt avail_in;
+         png_bytep buffer;
+
+         while (png_ptr->idat_size == 0)
+         {
+            png_crc_finish(png_ptr, 0);
+
+            png_ptr->idat_size = png_read_chunk_header(png_ptr);
+            /* This is an error even in the 'check' case because the code just
+             * consumed a non-IDAT header.
+             */
+            if (png_ptr->chunk_name != png_IDAT)
+               png_error(png_ptr, "Not enough image data");
+         }
+
+         avail_in = png_ptr->IDAT_read_size;
+
+         if (avail_in > png_ptr->idat_size)
+            avail_in = (uInt)png_ptr->idat_size;
+
+         /* A PNG with a gradually increasing IDAT size will defeat this attempt
+          * to minimize memory usage by causing lots of re-allocs, but
+          * realistically doing IDAT_read_size re-allocs is not likely to be a
+          * big problem.
+          */
+         buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
+
+         png_crc_read(png_ptr, buffer, avail_in);
+         png_ptr->idat_size -= avail_in;
+
+         png_ptr->zstream.next_in = buffer;
+         png_ptr->zstream.avail_in = avail_in;
+      }
+
+      /* And set up the output side. */
+      if (output != NULL) /* standard read */
+      {
+         uInt out = ZLIB_IO_MAX;
+
+         if (out > avail_out)
+            out = (uInt)avail_out;
+
+         avail_out -= out;
+         png_ptr->zstream.avail_out = out;
+      }
+
+      else /* after last row, checking for end */
+      {
+         png_ptr->zstream.next_out = tmpbuf;
+         png_ptr->zstream.avail_out = (sizeof tmpbuf);
+      }
+
+      /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
+       * process.  If the LZ stream is truncated the sequential reader will
+       * terminally damage the stream, above, by reading the chunk header of the
+       * following chunk (it then exits with png_error).
+       *
+       * TODO: deal more elegantly with truncated IDAT lists.
+       */
+      ret = PNG_INFLATE(png_ptr, Z_NO_FLUSH);
+
+      /* Take the unconsumed output back. */
+      if (output != NULL)
+         avail_out += png_ptr->zstream.avail_out;
+
+      else /* avail_out counts the extra bytes */
+         avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
+
+      png_ptr->zstream.avail_out = 0;
+
+      if (ret == Z_STREAM_END)
+      {
+         /* Do this for safety; we won't read any more into this row. */
+         png_ptr->zstream.next_out = NULL;
+
+         png_ptr->mode |= PNG_AFTER_IDAT;
+         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+
+         if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
+            png_chunk_benign_error(png_ptr, "Extra compressed data");
+         break;
+      }
+
+      if (ret != Z_OK)
+      {
+         png_zstream_error(png_ptr, ret);
+
+         if (output != NULL)
+            png_chunk_error(png_ptr, png_ptr->zstream.msg);
+
+         else /* checking */
+         {
+            png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
+            return;
+         }
+      }
+   } while (avail_out > 0);
+
+   if (avail_out > 0)
+   {
+      /* The stream ended before the image; this is the same as too few IDATs so
+       * should be handled the same way.
+       */
+      if (output != NULL)
+         png_error(png_ptr, "Not enough image data");
+
+      else /* the deflate stream contained extra data */
+         png_chunk_benign_error(png_ptr, "Too much image data");
+   }
+}
+
+void /* PRIVATE */
+png_read_finish_IDAT(png_structrp png_ptr)
+{
+   /* We don't need any more data and the stream should have ended, however the
+    * LZ end code may actually not have been processed.  In this case we must
+    * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
+    * may still remain to be consumed.
+    */
+   if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+   {
+      /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
+       * the compressed stream, but the stream may be damaged too, so even after
+       * this call we may need to terminate the zstream ownership.
+       */
+      png_read_IDAT_data(png_ptr, NULL, 0);
+      png_ptr->zstream.next_out = NULL; /* safety */
+
+      /* Now clear everything out for safety; the following may not have been
+       * done.
+       */
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+      {
+         png_ptr->mode |= PNG_AFTER_IDAT;
+         png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+      }
+   }
+
+   /* If the zstream has not been released do it now *and* terminate the reading
+    * of the final IDAT chunk.
+    */
+   if (png_ptr->zowner == png_IDAT)
+   {
+      /* Always do this; the pointers otherwise point into the read buffer. */
+      png_ptr->zstream.next_in = NULL;
+      png_ptr->zstream.avail_in = 0;
+
+      /* Now we no longer own the zstream. */
+      png_ptr->zowner = 0;
+
+      /* The slightly weird semantics of the sequential IDAT reading is that we
+       * are always in or at the end of an IDAT chunk, so we always need to do a
+       * crc_finish here.  If idat_size is non-zero we also need to read the
+       * spurious bytes at the end of the chunk now.
+       */
+      (void)png_crc_finish(png_ptr, png_ptr->idat_size);
+   }
+}
+
+void /* PRIVATE */
+png_read_finish_row(png_structrp png_ptr)
+{
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+
+   png_debug(1, "in png_read_finish_row");
+   png_ptr->row_number++;
+   if (png_ptr->row_number < png_ptr->num_rows)
+      return;
+
+   if (png_ptr->interlaced != 0)
+   {
+      png_ptr->row_number = 0;
+
+      /* TO DO: don't do this if prev_row isn't needed (requires
+       * read-ahead of the next row's filter byte.
+       */
+      memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+      do
+      {
+         png_ptr->pass++;
+
+         if (png_ptr->pass >= 7)
+            break;
+
+         png_ptr->iwidth = (png_ptr->width +
+            png_pass_inc[png_ptr->pass] - 1 -
+            png_pass_start[png_ptr->pass]) /
+            png_pass_inc[png_ptr->pass];
+
+         if ((png_ptr->transformations & PNG_INTERLACE) == 0)
+         {
+            png_ptr->num_rows = (png_ptr->height +
+                png_pass_yinc[png_ptr->pass] - 1 -
+                png_pass_ystart[png_ptr->pass]) /
+                png_pass_yinc[png_ptr->pass];
+         }
+
+         else  /* if (png_ptr->transformations & PNG_INTERLACE) */
+            break; /* libpng deinterlacing sees every row */
+
+      } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
+
+      if (png_ptr->pass < 7)
+         return;
+   }
+
+   /* Here after at the end of the last row of the last pass. */
+   png_read_finish_IDAT(png_ptr);
+}
+#endif /* SEQUENTIAL_READ */
+
+void /* PRIVATE */
+png_read_start_row(png_structrp png_ptr)
+{
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+
+   unsigned int max_pixel_depth;
+   size_t row_bytes;
+
+   png_debug(1, "in png_read_start_row");
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+   png_init_read_transformations(png_ptr);
+#endif
+   if (png_ptr->interlaced != 0)
+   {
+      if ((png_ptr->transformations & PNG_INTERLACE) == 0)
+         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+             png_pass_ystart[0]) / png_pass_yinc[0];
+
+      else
+         png_ptr->num_rows = png_ptr->height;
+
+      png_ptr->iwidth = (png_ptr->width +
+          png_pass_inc[png_ptr->pass] - 1 -
+          png_pass_start[png_ptr->pass]) /
+          png_pass_inc[png_ptr->pass];
+   }
+
+   else
+   {
+      png_ptr->num_rows = png_ptr->height;
+      png_ptr->iwidth = png_ptr->width;
+   }
+
+   max_pixel_depth = (unsigned int)png_ptr->pixel_depth;
+
+   /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
+    * calculations to calculate the final pixel depth, then
+    * png_do_read_transforms actually does the transforms.  This means that the
+    * code which effectively calculates this value is actually repeated in three
+    * separate places.  They must all match.  Innocent changes to the order of
+    * transformations can and will break libpng in a way that causes memory
+    * overwrites.
+    *
+    * TODO: fix this.
+    */
+#ifdef PNG_READ_PACK_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
+      max_pixel_depth = 8;
+#endif
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND) != 0)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         if (png_ptr->num_trans != 0)
+            max_pixel_depth = 32;
+
+         else
+            max_pixel_depth = 24;
+      }
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (max_pixel_depth < 8)
+            max_pixel_depth = 8;
+
+         if (png_ptr->num_trans != 0)
+            max_pixel_depth *= 2;
+      }
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+      {
+         if (png_ptr->num_trans != 0)
+         {
+            max_pixel_depth *= 4;
+            max_pixel_depth /= 3;
+         }
+      }
+   }
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
+   {
+#  ifdef PNG_READ_EXPAND_SUPPORTED
+      /* In fact it is an error if it isn't supported, but checking is
+       * the safe way.
+       */
+      if ((png_ptr->transformations & PNG_EXPAND) != 0)
+      {
+         if (png_ptr->bit_depth < 16)
+            max_pixel_depth *= 2;
+      }
+      else
+#  endif
+      png_ptr->transformations &= ~PNG_EXPAND_16;
+   }
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+   if ((png_ptr->transformations & (PNG_FILLER)) != 0)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (max_pixel_depth <= 8)
+            max_pixel_depth = 16;
+
+         else
+            max_pixel_depth = 32;
+      }
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+         png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         if (max_pixel_depth <= 32)
+            max_pixel_depth = 32;
+
+         else
+            max_pixel_depth = 64;
+      }
+   }
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
+   {
+      if (
+#ifdef PNG_READ_EXPAND_SUPPORTED
+          (png_ptr->num_trans != 0 &&
+          (png_ptr->transformations & PNG_EXPAND) != 0) ||
+#endif
+#ifdef PNG_READ_FILLER_SUPPORTED
+          (png_ptr->transformations & (PNG_FILLER)) != 0 ||
+#endif
+          png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (max_pixel_depth <= 16)
+            max_pixel_depth = 32;
+
+         else
+            max_pixel_depth = 64;
+      }
+
+      else
+      {
+         if (max_pixel_depth <= 8)
+         {
+            if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+               max_pixel_depth = 32;
+
+            else
+               max_pixel_depth = 24;
+         }
+
+         else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            max_pixel_depth = 64;
+
+         else
+            max_pixel_depth = 48;
+      }
+   }
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
+defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+   {
+      unsigned int user_pixel_depth = png_ptr->user_transform_depth *
+         png_ptr->user_transform_channels;
+
+      if (user_pixel_depth > max_pixel_depth)
+         max_pixel_depth = user_pixel_depth;
+   }
+#endif
+
+   /* This value is stored in png_struct and double checked in the row read
+    * code.
+    */
+   png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
+   png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
+
+   /* Align the width on the next larger 8 pixels.  Mainly used
+    * for interlacing
+    */
+   row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
+   /* Calculate the maximum bytes needed, adding a byte and a pixel
+    * for safety's sake
+    */
+   row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
+       1 + ((max_pixel_depth + 7) >> 3U);
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (row_bytes > (png_uint_32)65536L)
+      png_error(png_ptr, "This image requires a row greater than 64KB");
+#endif
+
+   if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
+   {
+      png_free(png_ptr, png_ptr->big_row_buf);
+      png_free(png_ptr, png_ptr->big_prev_row);
+
+      if (png_ptr->interlaced != 0)
+         png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
+             row_bytes + 48);
+
+      else
+         png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
+
+      png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
+
+#ifdef PNG_ALIGNED_MEMORY_SUPPORTED
+      /* Use 16-byte aligned memory for row_buf with at least 16 bytes
+       * of padding before and after row_buf; treat prev_row similarly.
+       * NOTE: the alignment is to the start of the pixels, one beyond the start
+       * of the buffer, because of the filter byte.  Prior to libpng 1.5.6 this
+       * was incorrect; the filter byte was aligned, which had the exact
+       * opposite effect of that intended.
+       */
+      {
+         png_bytep temp = png_ptr->big_row_buf + 32;
+         size_t extra = (size_t)temp & 0x0f;
+         png_ptr->row_buf = temp - extra - 1/*filter byte*/;
+
+         temp = png_ptr->big_prev_row + 32;
+         extra = (size_t)temp & 0x0f;
+         png_ptr->prev_row = temp - extra - 1/*filter byte*/;
+      }
+#else
+      /* Use 31 bytes of padding before and 17 bytes after row_buf. */
+      png_ptr->row_buf = png_ptr->big_row_buf + 31;
+      png_ptr->prev_row = png_ptr->big_prev_row + 31;
+#endif
+      png_ptr->old_big_row_buf_size = row_bytes + 48;
+   }
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (png_ptr->rowbytes > 65535)
+      png_error(png_ptr, "This image requires a row greater than 64KB");
+
+#endif
+   if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
+      png_error(png_ptr, "Row has too many bytes to allocate in memory");
+
+   memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+   png_debug1(3, "width = %u,", png_ptr->width);
+   png_debug1(3, "height = %u,", png_ptr->height);
+   png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
+   png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
+   png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
+   png_debug1(3, "irowbytes = %lu",
+       (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
+
+   /* The sequential reader needs a buffer for IDAT, but the progressive reader
+    * does not, so free the read buffer now regardless; the sequential reader
+    * reallocates it on demand.
+    */
+   if (png_ptr->read_buffer != NULL)
+   {
+      png_bytep buffer = png_ptr->read_buffer;
+
+      png_ptr->read_buffer_size = 0;
+      png_ptr->read_buffer = NULL;
+      png_free(png_ptr, buffer);
+   }
+
+   /* Finally claim the zstream for the inflate of the IDAT data, use the bits
+    * value from the stream (note that this will result in a fatal error if the
+    * IDAT stream has a bogus deflate header window_bits value, but this should
+    * not be happening any longer!)
+    */
+   if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
+      png_error(png_ptr, png_ptr->zstream.msg);
+
+   png_ptr->flags |= PNG_FLAG_ROW_INIT;
+}
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/pngset.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngset.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngset.c	(revision 107811)
@@ -0,0 +1,1803 @@
+
+/* pngset.c - storage of image information into info struct
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * The functions here are used during reads to store data from the file
+ * into the info struct, and during writes to store application data
+ * into the info struct for writing into the file.  This abstracts the
+ * info struct and allows us to change the structure in the future.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+#ifdef PNG_bKGD_SUPPORTED
+void PNGAPI
+png_set_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_color_16p background)
+{
+   png_debug1(1, "in %s storage function", "bKGD");
+
+   if (png_ptr == NULL || info_ptr == NULL || background == NULL)
+      return;
+
+   info_ptr->background = *background;
+   info_ptr->valid |= PNG_INFO_bKGD;
+}
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+void PNGFAPI
+png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
+    png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
+    png_fixed_point blue_x, png_fixed_point blue_y)
+{
+   png_xy xy;
+
+   png_debug1(1, "in %s storage function", "cHRM fixed");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   xy.redx = red_x;
+   xy.redy = red_y;
+   xy.greenx = green_x;
+   xy.greeny = green_y;
+   xy.bluex = blue_x;
+   xy.bluey = blue_y;
+   xy.whitex = white_x;
+   xy.whitey = white_y;
+
+   if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy,
+       2/* override with app values*/) != 0)
+      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+void PNGFAPI
+png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_fixed_point int_red_X, png_fixed_point int_red_Y,
+    png_fixed_point int_red_Z, png_fixed_point int_green_X,
+    png_fixed_point int_green_Y, png_fixed_point int_green_Z,
+    png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
+    png_fixed_point int_blue_Z)
+{
+   png_XYZ XYZ;
+
+   png_debug1(1, "in %s storage function", "cHRM XYZ fixed");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   XYZ.red_X = int_red_X;
+   XYZ.red_Y = int_red_Y;
+   XYZ.red_Z = int_red_Z;
+   XYZ.green_X = int_green_X;
+   XYZ.green_Y = int_green_Y;
+   XYZ.green_Z = int_green_Z;
+   XYZ.blue_X = int_blue_X;
+   XYZ.blue_Y = int_blue_Y;
+   XYZ.blue_Z = int_blue_Z;
+
+   if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
+       &XYZ, 2) != 0)
+      info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
+    double white_x, double white_y, double red_x, double red_y,
+    double green_x, double green_y, double blue_x, double blue_y)
+{
+   png_set_cHRM_fixed(png_ptr, info_ptr,
+       png_fixed(png_ptr, white_x, "cHRM White X"),
+       png_fixed(png_ptr, white_y, "cHRM White Y"),
+       png_fixed(png_ptr, red_x, "cHRM Red X"),
+       png_fixed(png_ptr, red_y, "cHRM Red Y"),
+       png_fixed(png_ptr, green_x, "cHRM Green X"),
+       png_fixed(png_ptr, green_y, "cHRM Green Y"),
+       png_fixed(png_ptr, blue_x, "cHRM Blue X"),
+       png_fixed(png_ptr, blue_y, "cHRM Blue Y"));
+}
+
+void PNGAPI
+png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X,
+    double red_Y, double red_Z, double green_X, double green_Y, double green_Z,
+    double blue_X, double blue_Y, double blue_Z)
+{
+   png_set_cHRM_XYZ_fixed(png_ptr, info_ptr,
+       png_fixed(png_ptr, red_X, "cHRM Red X"),
+       png_fixed(png_ptr, red_Y, "cHRM Red Y"),
+       png_fixed(png_ptr, red_Z, "cHRM Red Z"),
+       png_fixed(png_ptr, green_X, "cHRM Green X"),
+       png_fixed(png_ptr, green_Y, "cHRM Green Y"),
+       png_fixed(png_ptr, green_Z, "cHRM Green Z"),
+       png_fixed(png_ptr, blue_X, "cHRM Blue X"),
+       png_fixed(png_ptr, blue_Y, "cHRM Blue Y"),
+       png_fixed(png_ptr, blue_Z, "cHRM Blue Z"));
+}
+#  endif /* FLOATING_POINT */
+
+#endif /* cHRM */
+
+#ifdef PNG_eXIf_SUPPORTED
+void PNGAPI
+png_set_eXIf(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_bytep exif)
+{
+  png_warning(png_ptr, "png_set_eXIf does not work; use png_set_eXIf_1");
+  PNG_UNUSED(info_ptr)
+  PNG_UNUSED(exif)
+}
+
+void PNGAPI
+png_set_eXIf_1(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_uint_32 num_exif, png_bytep exif)
+{
+   png_bytep new_exif;
+
+   png_debug1(1, "in %s storage function", "eXIf");
+
+   if (png_ptr == NULL || info_ptr == NULL ||
+       (png_ptr->mode & PNG_WROTE_eXIf) != 0)
+      return;
+
+   new_exif = png_voidcast(png_bytep, png_malloc_warn(png_ptr, num_exif));
+
+   if (new_exif == NULL)
+   {
+      png_warning(png_ptr, "Insufficient memory for eXIf chunk data");
+      return;
+   }
+
+   memcpy(new_exif, exif, (size_t)num_exif);
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_EXIF, 0);
+
+   info_ptr->num_exif = num_exif;
+   info_ptr->exif = new_exif;
+   info_ptr->free_me |= PNG_FREE_EXIF;
+   info_ptr->valid |= PNG_INFO_eXIf;
+}
+#endif /* eXIf */
+
+#ifdef PNG_gAMA_SUPPORTED
+void PNGFAPI
+png_set_gAMA_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_fixed_point file_gamma)
+{
+   png_debug1(1, "in %s storage function", "gAMA");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_colorspace_set_gamma(png_ptr, &info_ptr->colorspace, file_gamma);
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_gAMA(png_const_structrp png_ptr, png_inforp info_ptr, double file_gamma)
+{
+   png_set_gAMA_fixed(png_ptr, info_ptr, png_fixed(png_ptr, file_gamma,
+       "png_set_gAMA"));
+}
+#  endif
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+void PNGAPI
+png_set_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_uint_16p hist)
+{
+   int i;
+
+   png_debug1(1, "in %s storage function", "hIST");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (info_ptr->num_palette == 0 || info_ptr->num_palette
+       > PNG_MAX_PALETTE_LENGTH)
+   {
+      png_warning(png_ptr,
+          "Invalid palette size, hIST allocation skipped");
+
+      return;
+   }
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0);
+
+   /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in
+    * version 1.2.1
+    */
+   info_ptr->hist = png_voidcast(png_uint_16p, png_malloc_warn(png_ptr,
+       PNG_MAX_PALETTE_LENGTH * (sizeof (png_uint_16))));
+
+   if (info_ptr->hist == NULL)
+   {
+      png_warning(png_ptr, "Insufficient memory for hIST chunk data");
+      return;
+   }
+
+   for (i = 0; i < info_ptr->num_palette; i++)
+      info_ptr->hist[i] = hist[i];
+
+   info_ptr->free_me |= PNG_FREE_HIST;
+   info_ptr->valid |= PNG_INFO_hIST;
+}
+#endif
+
+void PNGAPI
+png_set_IHDR(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_uint_32 width, png_uint_32 height, int bit_depth,
+    int color_type, int interlace_type, int compression_type,
+    int filter_type)
+{
+   png_debug1(1, "in %s storage function", "IHDR");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->width = width;
+   info_ptr->height = height;
+   info_ptr->bit_depth = (png_byte)bit_depth;
+   info_ptr->color_type = (png_byte)color_type;
+   info_ptr->compression_type = (png_byte)compression_type;
+   info_ptr->filter_type = (png_byte)filter_type;
+   info_ptr->interlace_type = (png_byte)interlace_type;
+
+   png_check_IHDR (png_ptr, info_ptr->width, info_ptr->height,
+       info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
+       info_ptr->compression_type, info_ptr->filter_type);
+
+   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      info_ptr->channels = 1;
+
+   else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      info_ptr->channels = 3;
+
+   else
+      info_ptr->channels = 1;
+
+   if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      info_ptr->channels++;
+
+   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
+
+   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
+}
+
+#ifdef PNG_oFFs_SUPPORTED
+void PNGAPI
+png_set_oFFs(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_int_32 offset_x, png_int_32 offset_y, int unit_type)
+{
+   png_debug1(1, "in %s storage function", "oFFs");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->x_offset = offset_x;
+   info_ptr->y_offset = offset_y;
+   info_ptr->offset_unit_type = (png_byte)unit_type;
+   info_ptr->valid |= PNG_INFO_oFFs;
+}
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+void PNGAPI
+png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type,
+    int nparams, png_const_charp units, png_charpp params)
+{
+   size_t length;
+   int i;
+
+   png_debug1(1, "in %s storage function", "pCAL");
+
+   if (png_ptr == NULL || info_ptr == NULL || purpose == NULL || units == NULL
+       || (nparams > 0 && params == NULL))
+      return;
+
+   length = strlen(purpose) + 1;
+   png_debug1(3, "allocating purpose for info (%lu bytes)",
+       (unsigned long)length);
+
+   /* TODO: validate format of calibration name and unit name */
+
+   /* Check that the type matches the specification. */
+   if (type < 0 || type > 3)
+   {
+      png_chunk_report(png_ptr, "Invalid pCAL equation type",
+            PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   if (nparams < 0 || nparams > 255)
+   {
+      png_chunk_report(png_ptr, "Invalid pCAL parameter count",
+            PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   /* Validate params[nparams] */
+   for (i=0; i<nparams; ++i)
+   {
+      if (params[i] == NULL ||
+          !png_check_fp_string(params[i], strlen(params[i])))
+      {
+         png_chunk_report(png_ptr, "Invalid format for pCAL parameter",
+               PNG_CHUNK_WRITE_ERROR);
+         return;
+      }
+   }
+
+   info_ptr->pcal_purpose = png_voidcast(png_charp,
+       png_malloc_warn(png_ptr, length));
+
+   if (info_ptr->pcal_purpose == NULL)
+   {
+      png_chunk_report(png_ptr, "Insufficient memory for pCAL purpose",
+            PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   memcpy(info_ptr->pcal_purpose, purpose, length);
+
+   info_ptr->free_me |= PNG_FREE_PCAL;
+
+   png_debug(3, "storing X0, X1, type, and nparams in info");
+   info_ptr->pcal_X0 = X0;
+   info_ptr->pcal_X1 = X1;
+   info_ptr->pcal_type = (png_byte)type;
+   info_ptr->pcal_nparams = (png_byte)nparams;
+
+   length = strlen(units) + 1;
+   png_debug1(3, "allocating units for info (%lu bytes)",
+       (unsigned long)length);
+
+   info_ptr->pcal_units = png_voidcast(png_charp,
+       png_malloc_warn(png_ptr, length));
+
+   if (info_ptr->pcal_units == NULL)
+   {
+      png_warning(png_ptr, "Insufficient memory for pCAL units");
+      return;
+   }
+
+   memcpy(info_ptr->pcal_units, units, length);
+
+   info_ptr->pcal_params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
+       (size_t)(((unsigned int)nparams + 1) * (sizeof (png_charp)))));
+
+   if (info_ptr->pcal_params == NULL)
+   {
+      png_warning(png_ptr, "Insufficient memory for pCAL params");
+      return;
+   }
+
+   memset(info_ptr->pcal_params, 0, ((unsigned int)nparams + 1) *
+       (sizeof (png_charp)));
+
+   for (i = 0; i < nparams; i++)
+   {
+      length = strlen(params[i]) + 1;
+      png_debug2(3, "allocating parameter %d for info (%lu bytes)", i,
+          (unsigned long)length);
+
+      info_ptr->pcal_params[i] = (png_charp)png_malloc_warn(png_ptr, length);
+
+      if (info_ptr->pcal_params[i] == NULL)
+      {
+         png_warning(png_ptr, "Insufficient memory for pCAL parameter");
+         return;
+      }
+
+      memcpy(info_ptr->pcal_params[i], params[i], length);
+   }
+
+   info_ptr->valid |= PNG_INFO_pCAL;
+}
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+void PNGAPI
+png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
+    int unit, png_const_charp swidth, png_const_charp sheight)
+{
+   size_t lengthw = 0, lengthh = 0;
+
+   png_debug1(1, "in %s storage function", "sCAL");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* Double check the unit (should never get here with an invalid
+    * unit unless this is an API call.)
+    */
+   if (unit != 1 && unit != 2)
+      png_error(png_ptr, "Invalid sCAL unit");
+
+   if (swidth == NULL || (lengthw = strlen(swidth)) == 0 ||
+       swidth[0] == 45 /* '-' */ || !png_check_fp_string(swidth, lengthw))
+      png_error(png_ptr, "Invalid sCAL width");
+
+   if (sheight == NULL || (lengthh = strlen(sheight)) == 0 ||
+       sheight[0] == 45 /* '-' */ || !png_check_fp_string(sheight, lengthh))
+      png_error(png_ptr, "Invalid sCAL height");
+
+   info_ptr->scal_unit = (png_byte)unit;
+
+   ++lengthw;
+
+   png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthw);
+
+   info_ptr->scal_s_width = png_voidcast(png_charp,
+       png_malloc_warn(png_ptr, lengthw));
+
+   if (info_ptr->scal_s_width == NULL)
+   {
+      png_warning(png_ptr, "Memory allocation failed while processing sCAL");
+
+      return;
+   }
+
+   memcpy(info_ptr->scal_s_width, swidth, lengthw);
+
+   ++lengthh;
+
+   png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthh);
+
+   info_ptr->scal_s_height = png_voidcast(png_charp,
+       png_malloc_warn(png_ptr, lengthh));
+
+   if (info_ptr->scal_s_height == NULL)
+   {
+      png_free(png_ptr, info_ptr->scal_s_width);
+      info_ptr->scal_s_width = NULL;
+
+      png_warning(png_ptr, "Memory allocation failed while processing sCAL");
+      return;
+   }
+
+   memcpy(info_ptr->scal_s_height, sheight, lengthh);
+
+   info_ptr->free_me |= PNG_FREE_SCAL;
+   info_ptr->valid |= PNG_INFO_sCAL;
+}
+
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
+    double width, double height)
+{
+   png_debug1(1, "in %s storage function", "sCAL");
+
+   /* Check the arguments. */
+   if (width <= 0)
+      png_warning(png_ptr, "Invalid sCAL width ignored");
+
+   else if (height <= 0)
+      png_warning(png_ptr, "Invalid sCAL height ignored");
+
+   else
+   {
+      /* Convert 'width' and 'height' to ASCII. */
+      char swidth[PNG_sCAL_MAX_DIGITS+1];
+      char sheight[PNG_sCAL_MAX_DIGITS+1];
+
+      png_ascii_from_fp(png_ptr, swidth, (sizeof swidth), width,
+          PNG_sCAL_PRECISION);
+      png_ascii_from_fp(png_ptr, sheight, (sizeof sheight), height,
+          PNG_sCAL_PRECISION);
+
+      png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
+   }
+}
+#  endif
+
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL_fixed(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
+    png_fixed_point width, png_fixed_point height)
+{
+   png_debug1(1, "in %s storage function", "sCAL");
+
+   /* Check the arguments. */
+   if (width <= 0)
+      png_warning(png_ptr, "Invalid sCAL width ignored");
+
+   else if (height <= 0)
+      png_warning(png_ptr, "Invalid sCAL height ignored");
+
+   else
+   {
+      /* Convert 'width' and 'height' to ASCII. */
+      char swidth[PNG_sCAL_MAX_DIGITS+1];
+      char sheight[PNG_sCAL_MAX_DIGITS+1];
+
+      png_ascii_from_fixed(png_ptr, swidth, (sizeof swidth), width);
+      png_ascii_from_fixed(png_ptr, sheight, (sizeof sheight), height);
+
+      png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
+   }
+}
+#  endif
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+void PNGAPI
+png_set_pHYs(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_uint_32 res_x, png_uint_32 res_y, int unit_type)
+{
+   png_debug1(1, "in %s storage function", "pHYs");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->x_pixels_per_unit = res_x;
+   info_ptr->y_pixels_per_unit = res_y;
+   info_ptr->phys_unit_type = (png_byte)unit_type;
+   info_ptr->valid |= PNG_INFO_pHYs;
+}
+#endif
+
+void PNGAPI
+png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
+    png_const_colorp palette, int num_palette)
+{
+
+   png_uint_32 max_palette_length;
+
+   png_debug1(1, "in %s storage function", "PLTE");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   max_palette_length = (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
+      (1 << info_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
+
+   if (num_palette < 0 || num_palette > (int) max_palette_length)
+   {
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+         png_error(png_ptr, "Invalid palette length");
+
+      else
+      {
+         png_warning(png_ptr, "Invalid palette length");
+
+         return;
+      }
+   }
+
+   if ((num_palette > 0 && palette == NULL) ||
+      (num_palette == 0
+#        ifdef PNG_MNG_FEATURES_SUPPORTED
+            && (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0
+#        endif
+      ))
+   {
+      png_error(png_ptr, "Invalid palette");
+   }
+
+   /* It may not actually be necessary to set png_ptr->palette here;
+    * we do it for backward compatibility with the way the png_handle_tRNS
+    * function used to do the allocation.
+    *
+    * 1.6.0: the above statement appears to be incorrect; something has to set
+    * the palette inside png_struct on read.
+    */
+   png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0);
+
+   /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
+    * of num_palette entries, in case of an invalid PNG file or incorrect
+    * call to png_set_PLTE() with too-large sample values.
+    */
+   png_ptr->palette = png_voidcast(png_colorp, png_calloc(png_ptr,
+       PNG_MAX_PALETTE_LENGTH * (sizeof (png_color))));
+
+   if (num_palette > 0)
+      memcpy(png_ptr->palette, palette, (unsigned int)num_palette *
+          (sizeof (png_color)));
+
+   info_ptr->palette = png_ptr->palette;
+   info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;
+   info_ptr->free_me |= PNG_FREE_PLTE;
+   info_ptr->valid |= PNG_INFO_PLTE;
+}
+
+#ifdef PNG_sBIT_SUPPORTED
+void PNGAPI
+png_set_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_color_8p sig_bit)
+{
+   png_debug1(1, "in %s storage function", "sBIT");
+
+   if (png_ptr == NULL || info_ptr == NULL || sig_bit == NULL)
+      return;
+
+   info_ptr->sig_bit = *sig_bit;
+   info_ptr->valid |= PNG_INFO_sBIT;
+}
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+void PNGAPI
+png_set_sRGB(png_const_structrp png_ptr, png_inforp info_ptr, int srgb_intent)
+{
+   png_debug1(1, "in %s storage function", "sRGB");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   (void)png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent);
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+void PNGAPI
+png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
+    int srgb_intent)
+{
+   png_debug1(1, "in %s storage function", "sRGB_gAMA_and_cHRM");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
+       srgb_intent) != 0)
+   {
+      /* This causes the gAMA and cHRM to be written too */
+      info_ptr->colorspace.flags |=
+         PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
+   }
+
+   png_colorspace_sync_info(png_ptr, info_ptr);
+}
+#endif /* sRGB */
+
+
+#ifdef PNG_iCCP_SUPPORTED
+void PNGAPI
+png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_charp name, int compression_type,
+    png_const_bytep profile, png_uint_32 proflen)
+{
+   png_charp new_iccp_name;
+   png_bytep new_iccp_profile;
+   size_t length;
+
+   png_debug1(1, "in %s storage function", "iCCP");
+
+   if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL)
+      return;
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+      png_app_error(png_ptr, "Invalid iCCP compression method");
+
+   /* Set the colorspace first because this validates the profile; do not
+    * override previously set app cHRM or gAMA here (because likely as not the
+    * application knows better than libpng what the correct values are.)  Pass
+    * the info_ptr color_type field to png_colorspace_set_ICC because in the
+    * write case it has not yet been stored in png_ptr.
+    */
+   {
+      int result = png_colorspace_set_ICC(png_ptr, &info_ptr->colorspace, name,
+          proflen, profile, info_ptr->color_type);
+
+      png_colorspace_sync_info(png_ptr, info_ptr);
+
+      /* Don't do any of the copying if the profile was bad, or inconsistent. */
+      if (result == 0)
+         return;
+
+      /* But do write the gAMA and cHRM chunks from the profile. */
+      info_ptr->colorspace.flags |=
+         PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
+   }
+
+   length = strlen(name)+1;
+   new_iccp_name = png_voidcast(png_charp, png_malloc_warn(png_ptr, length));
+
+   if (new_iccp_name == NULL)
+   {
+      png_benign_error(png_ptr, "Insufficient memory to process iCCP chunk");
+
+      return;
+   }
+
+   memcpy(new_iccp_name, name, length);
+   new_iccp_profile = png_voidcast(png_bytep,
+       png_malloc_warn(png_ptr, proflen));
+
+   if (new_iccp_profile == NULL)
+   {
+      png_free(png_ptr, new_iccp_name);
+      png_benign_error(png_ptr,
+          "Insufficient memory to process iCCP profile");
+
+      return;
+   }
+
+   memcpy(new_iccp_profile, profile, proflen);
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0);
+
+   info_ptr->iccp_proflen = proflen;
+   info_ptr->iccp_name = new_iccp_name;
+   info_ptr->iccp_profile = new_iccp_profile;
+   info_ptr->free_me |= PNG_FREE_ICCP;
+   info_ptr->valid |= PNG_INFO_iCCP;
+}
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+void PNGAPI
+png_set_text(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_textp text_ptr, int num_text)
+{
+   int ret;
+   ret = png_set_text_2(png_ptr, info_ptr, text_ptr, num_text);
+
+   if (ret != 0)
+      png_error(png_ptr, "Insufficient memory to store text");
+}
+
+int /* PRIVATE */
+png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_textp text_ptr, int num_text)
+{
+   int i;
+
+   png_debug1(1, "in text storage function, chunk typeid = 0x%lx",
+      png_ptr == NULL ? 0xabadca11UL : (unsigned long)png_ptr->chunk_name);
+
+   if (png_ptr == NULL || info_ptr == NULL || num_text <= 0 || text_ptr == NULL)
+      return 0;
+
+   /* Make sure we have enough space in the "text" array in info_struct
+    * to hold all of the incoming text_ptr objects.  This compare can't overflow
+    * because max_text >= num_text (anyway, subtract of two positive integers
+    * can't overflow in any case.)
+    */
+   if (num_text > info_ptr->max_text - info_ptr->num_text)
+   {
+      int old_num_text = info_ptr->num_text;
+      int max_text;
+      png_textp new_text = NULL;
+
+      /* Calculate an appropriate max_text, checking for overflow. */
+      max_text = old_num_text;
+      if (num_text <= INT_MAX - max_text)
+      {
+         max_text += num_text;
+
+         /* Round up to a multiple of 8 */
+         if (max_text < INT_MAX-8)
+            max_text = (max_text + 8) & ~0x7;
+
+         else
+            max_text = INT_MAX;
+
+         /* Now allocate a new array and copy the old members in; this does all
+          * the overflow checks.
+          */
+         new_text = png_voidcast(png_textp,png_realloc_array(png_ptr,
+             info_ptr->text, old_num_text, max_text-old_num_text,
+             sizeof *new_text));
+      }
+
+      if (new_text == NULL)
+      {
+         png_chunk_report(png_ptr, "too many text chunks",
+             PNG_CHUNK_WRITE_ERROR);
+
+         return 1;
+      }
+
+      png_free(png_ptr, info_ptr->text);
+
+      info_ptr->text = new_text;
+      info_ptr->free_me |= PNG_FREE_TEXT;
+      info_ptr->max_text = max_text;
+      /* num_text is adjusted below as the entries are copied in */
+
+      png_debug1(3, "allocated %d entries for info_ptr->text", max_text);
+   }
+
+   for (i = 0; i < num_text; i++)
+   {
+      size_t text_length, key_len;
+      size_t lang_len, lang_key_len;
+      png_textp textp = &(info_ptr->text[info_ptr->num_text]);
+
+      if (text_ptr[i].key == NULL)
+          continue;
+
+      if (text_ptr[i].compression < PNG_TEXT_COMPRESSION_NONE ||
+          text_ptr[i].compression >= PNG_TEXT_COMPRESSION_LAST)
+      {
+         png_chunk_report(png_ptr, "text compression mode is out of range",
+             PNG_CHUNK_WRITE_ERROR);
+         continue;
+      }
+
+      key_len = strlen(text_ptr[i].key);
+
+      if (text_ptr[i].compression <= 0)
+      {
+         lang_len = 0;
+         lang_key_len = 0;
+      }
+
+      else
+#  ifdef PNG_iTXt_SUPPORTED
+      {
+         /* Set iTXt data */
+
+         if (text_ptr[i].lang != NULL)
+            lang_len = strlen(text_ptr[i].lang);
+
+         else
+            lang_len = 0;
+
+         if (text_ptr[i].lang_key != NULL)
+            lang_key_len = strlen(text_ptr[i].lang_key);
+
+         else
+            lang_key_len = 0;
+      }
+#  else /* iTXt */
+      {
+         png_chunk_report(png_ptr, "iTXt chunk not supported",
+             PNG_CHUNK_WRITE_ERROR);
+         continue;
+      }
+#  endif
+
+      if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0')
+      {
+         text_length = 0;
+#  ifdef PNG_iTXt_SUPPORTED
+         if (text_ptr[i].compression > 0)
+            textp->compression = PNG_ITXT_COMPRESSION_NONE;
+
+         else
+#  endif
+            textp->compression = PNG_TEXT_COMPRESSION_NONE;
+      }
+
+      else
+      {
+         text_length = strlen(text_ptr[i].text);
+         textp->compression = text_ptr[i].compression;
+      }
+
+      textp->key = png_voidcast(png_charp,png_malloc_base(png_ptr,
+          key_len + text_length + lang_len + lang_key_len + 4));
+
+      if (textp->key == NULL)
+      {
+         png_chunk_report(png_ptr, "text chunk: out of memory",
+             PNG_CHUNK_WRITE_ERROR);
+
+         return 1;
+      }
+
+      png_debug2(2, "Allocated %lu bytes at %p in png_set_text",
+          (unsigned long)(png_uint_32)
+          (key_len + lang_len + lang_key_len + text_length + 4),
+          textp->key);
+
+      memcpy(textp->key, text_ptr[i].key, key_len);
+      *(textp->key + key_len) = '\0';
+
+      if (text_ptr[i].compression > 0)
+      {
+         textp->lang = textp->key + key_len + 1;
+         memcpy(textp->lang, text_ptr[i].lang, lang_len);
+         *(textp->lang + lang_len) = '\0';
+         textp->lang_key = textp->lang + lang_len + 1;
+         memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len);
+         *(textp->lang_key + lang_key_len) = '\0';
+         textp->text = textp->lang_key + lang_key_len + 1;
+      }
+
+      else
+      {
+         textp->lang=NULL;
+         textp->lang_key=NULL;
+         textp->text = textp->key + key_len + 1;
+      }
+
+      if (text_length != 0)
+         memcpy(textp->text, text_ptr[i].text, text_length);
+
+      *(textp->text + text_length) = '\0';
+
+#  ifdef PNG_iTXt_SUPPORTED
+      if (textp->compression > 0)
+      {
+         textp->text_length = 0;
+         textp->itxt_length = text_length;
+      }
+
+      else
+#  endif
+      {
+         textp->text_length = text_length;
+         textp->itxt_length = 0;
+      }
+
+      info_ptr->num_text++;
+      png_debug1(3, "transferred text chunk %d", info_ptr->num_text);
+   }
+
+   return 0;
+}
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+void PNGAPI
+png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_const_timep mod_time)
+{
+   png_debug1(1, "in %s storage function", "tIME");
+
+   if (png_ptr == NULL || info_ptr == NULL || mod_time == NULL ||
+       (png_ptr->mode & PNG_WROTE_tIME) != 0)
+      return;
+
+   if (mod_time->month == 0   || mod_time->month > 12  ||
+       mod_time->day   == 0   || mod_time->day   > 31  ||
+       mod_time->hour  > 23   || mod_time->minute > 59 ||
+       mod_time->second > 60)
+   {
+      png_warning(png_ptr, "Ignoring invalid time value");
+
+      return;
+   }
+
+   info_ptr->mod_time = *mod_time;
+   info_ptr->valid |= PNG_INFO_tIME;
+}
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+void PNGAPI
+png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
+    png_const_bytep trans_alpha, int num_trans, png_const_color_16p trans_color)
+{
+   png_debug1(1, "in %s storage function", "tRNS");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+
+      return;
+
+   if (trans_alpha != NULL)
+   {
+       /* It may not actually be necessary to set png_ptr->trans_alpha here;
+        * we do it for backward compatibility with the way the png_handle_tRNS
+        * function used to do the allocation.
+        *
+        * 1.6.0: The above statement is incorrect; png_handle_tRNS effectively
+        * relies on png_set_tRNS storing the information in png_struct
+        * (otherwise it won't be there for the code in pngrtran.c).
+        */
+
+       png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
+
+       if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
+       {
+         /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
+          info_ptr->trans_alpha = png_voidcast(png_bytep,
+              png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));
+          memcpy(info_ptr->trans_alpha, trans_alpha, (size_t)num_trans);
+
+          info_ptr->free_me |= PNG_FREE_TRNS;
+          info_ptr->valid |= PNG_INFO_tRNS;
+       }
+       png_ptr->trans_alpha = info_ptr->trans_alpha;
+   }
+
+   if (trans_color != NULL)
+   {
+#ifdef PNG_WARNINGS_SUPPORTED
+      if (info_ptr->bit_depth < 16)
+      {
+         int sample_max = (1 << info_ptr->bit_depth) - 1;
+
+         if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
+             trans_color->gray > sample_max) ||
+             (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+             (trans_color->red > sample_max ||
+             trans_color->green > sample_max ||
+             trans_color->blue > sample_max)))
+            png_warning(png_ptr,
+                "tRNS chunk has out-of-range samples for bit_depth");
+      }
+#endif
+
+      info_ptr->trans_color = *trans_color;
+
+      if (num_trans == 0)
+         num_trans = 1;
+   }
+
+   info_ptr->num_trans = (png_uint_16)num_trans;
+
+   if (num_trans != 0)
+   {
+      info_ptr->free_me |= PNG_FREE_TRNS;
+      info_ptr->valid |= PNG_INFO_tRNS;
+   }
+}
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+void PNGAPI
+png_set_sPLT(png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)
+/*
+ *  entries        - array of png_sPLT_t structures
+ *                   to be added to the list of palettes
+ *                   in the info structure.
+ *
+ *  nentries       - number of palette structures to be
+ *                   added.
+ */
+{
+   png_sPLT_tp np;
+
+   png_debug1(1, "in %s storage function", "sPLT");
+
+   if (png_ptr == NULL || info_ptr == NULL || nentries <= 0 || entries == NULL)
+      return;
+
+   /* Use the internal realloc function, which checks for all the possible
+    * overflows.  Notice that the parameters are (int) and (size_t)
+    */
+   np = png_voidcast(png_sPLT_tp,png_realloc_array(png_ptr,
+       info_ptr->splt_palettes, info_ptr->splt_palettes_num, nentries,
+       sizeof *np));
+
+   if (np == NULL)
+   {
+      /* Out of memory or too many chunks */
+      png_chunk_report(png_ptr, "too many sPLT chunks", PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   png_free(png_ptr, info_ptr->splt_palettes);
+
+   info_ptr->splt_palettes = np;
+   info_ptr->free_me |= PNG_FREE_SPLT;
+
+   np += info_ptr->splt_palettes_num;
+
+   do
+   {
+      size_t length;
+
+      /* Skip invalid input entries */
+      if (entries->name == NULL || entries->entries == NULL)
+      {
+         /* png_handle_sPLT doesn't do this, so this is an app error */
+         png_app_error(png_ptr, "png_set_sPLT: invalid sPLT");
+         /* Just skip the invalid entry */
+         continue;
+      }
+
+      np->depth = entries->depth;
+
+      /* In the event of out-of-memory just return - there's no point keeping
+       * on trying to add sPLT chunks.
+       */
+      length = strlen(entries->name) + 1;
+      np->name = png_voidcast(png_charp, png_malloc_base(png_ptr, length));
+
+      if (np->name == NULL)
+         break;
+
+      memcpy(np->name, entries->name, length);
+
+      /* IMPORTANT: we have memory now that won't get freed if something else
+       * goes wrong; this code must free it.  png_malloc_array produces no
+       * warnings; use a png_chunk_report (below) if there is an error.
+       */
+      np->entries = png_voidcast(png_sPLT_entryp, png_malloc_array(png_ptr,
+          entries->nentries, sizeof (png_sPLT_entry)));
+
+      if (np->entries == NULL)
+      {
+         png_free(png_ptr, np->name);
+         np->name = NULL;
+         break;
+      }
+
+      np->nentries = entries->nentries;
+      /* This multiply can't overflow because png_malloc_array has already
+       * checked it when doing the allocation.
+       */
+      memcpy(np->entries, entries->entries,
+          (unsigned int)entries->nentries * sizeof (png_sPLT_entry));
+
+      /* Note that 'continue' skips the advance of the out pointer and out
+       * count, so an invalid entry is not added.
+       */
+      info_ptr->valid |= PNG_INFO_sPLT;
+      ++(info_ptr->splt_palettes_num);
+      ++np;
+      ++entries;
+   }
+   while (--nentries);
+
+   if (nentries > 0)
+      png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
+}
+#endif /* sPLT */
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+static png_byte
+check_location(png_const_structrp png_ptr, int location)
+{
+   location &= (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT);
+
+   /* New in 1.6.0; copy the location and check it.  This is an API
+    * change; previously the app had to use the
+    * png_set_unknown_chunk_location API below for each chunk.
+    */
+   if (location == 0 && (png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+   {
+      /* Write struct, so unknown chunks come from the app */
+      png_app_warning(png_ptr,
+          "png_set_unknown_chunks now expects a valid location");
+      /* Use the old behavior */
+      location = (png_byte)(png_ptr->mode &
+          (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT));
+   }
+
+   /* This need not be an internal error - if the app calls
+    * png_set_unknown_chunks on a read pointer it must get the location right.
+    */
+   if (location == 0)
+      png_error(png_ptr, "invalid location in png_set_unknown_chunks");
+
+   /* Now reduce the location to the top-most set bit by removing each least
+    * significant bit in turn.
+    */
+   while (location != (location & -location))
+      location &= ~(location & -location);
+
+   /* The cast is safe because 'location' is a bit mask and only the low four
+    * bits are significant.
+    */
+   return (png_byte)location;
+}
+
+void PNGAPI
+png_set_unknown_chunks(png_const_structrp png_ptr,
+    png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
+{
+   png_unknown_chunkp np;
+
+   if (png_ptr == NULL || info_ptr == NULL || num_unknowns <= 0 ||
+       unknowns == NULL)
+      return;
+
+   /* Check for the failure cases where support has been disabled at compile
+    * time.  This code is hardly ever compiled - it's here because
+    * STORE_UNKNOWN_CHUNKS is set by both read and write code (compiling in this
+    * code) but may be meaningless if the read or write handling of unknown
+    * chunks is not compiled in.
+    */
+#  if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \
+      defined(PNG_READ_SUPPORTED)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+      {
+         png_app_error(png_ptr, "no unknown chunk support on read");
+
+         return;
+      }
+#  endif
+#  if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \
+      defined(PNG_WRITE_SUPPORTED)
+      if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+      {
+         png_app_error(png_ptr, "no unknown chunk support on write");
+
+         return;
+      }
+#  endif
+
+   /* Prior to 1.6.0 this code used png_malloc_warn; however, this meant that
+    * unknown critical chunks could be lost with just a warning resulting in
+    * undefined behavior.  Now png_chunk_report is used to provide behavior
+    * appropriate to read or write.
+    */
+   np = png_voidcast(png_unknown_chunkp, png_realloc_array(png_ptr,
+       info_ptr->unknown_chunks, info_ptr->unknown_chunks_num, num_unknowns,
+       sizeof *np));
+
+   if (np == NULL)
+   {
+      png_chunk_report(png_ptr, "too many unknown chunks",
+          PNG_CHUNK_WRITE_ERROR);
+      return;
+   }
+
+   png_free(png_ptr, info_ptr->unknown_chunks);
+
+   info_ptr->unknown_chunks = np; /* safe because it is initialized */
+   info_ptr->free_me |= PNG_FREE_UNKN;
+
+   np += info_ptr->unknown_chunks_num;
+
+   /* Increment unknown_chunks_num each time round the loop to protect the
+    * just-allocated chunk data.
+    */
+   for (; num_unknowns > 0; --num_unknowns, ++unknowns)
+   {
+      memcpy(np->name, unknowns->name, (sizeof np->name));
+      np->name[(sizeof np->name)-1] = '\0';
+      np->location = check_location(png_ptr, unknowns->location);
+
+      if (unknowns->size == 0)
+      {
+         np->data = NULL;
+         np->size = 0;
+      }
+
+      else
+      {
+         np->data = png_voidcast(png_bytep,
+             png_malloc_base(png_ptr, unknowns->size));
+
+         if (np->data == NULL)
+         {
+            png_chunk_report(png_ptr, "unknown chunk: out of memory",
+                PNG_CHUNK_WRITE_ERROR);
+            /* But just skip storing the unknown chunk */
+            continue;
+         }
+
+         memcpy(np->data, unknowns->data, unknowns->size);
+         np->size = unknowns->size;
+      }
+
+      /* These increments are skipped on out-of-memory for the data - the
+       * unknown chunk entry gets overwritten if the png_chunk_report returns.
+       * This is correct in the read case (the chunk is just dropped.)
+       */
+      ++np;
+      ++(info_ptr->unknown_chunks_num);
+   }
+}
+
+void PNGAPI
+png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
+    int chunk, int location)
+{
+   /* This API is pretty pointless in 1.6.0 because the location can be set
+    * before the call to png_set_unknown_chunks.
+    *
+    * TODO: add a png_app_warning in 1.7
+    */
+   if (png_ptr != NULL && info_ptr != NULL && chunk >= 0 &&
+      chunk < info_ptr->unknown_chunks_num)
+   {
+      if ((location & (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT)) == 0)
+      {
+         png_app_error(png_ptr, "invalid unknown chunk location");
+         /* Fake out the pre 1.6.0 behavior: */
+         if (((unsigned int)location & PNG_HAVE_IDAT) != 0) /* undocumented! */
+            location = PNG_AFTER_IDAT;
+
+         else
+            location = PNG_HAVE_IHDR; /* also undocumented */
+      }
+
+      info_ptr->unknown_chunks[chunk].location =
+         check_location(png_ptr, location);
+   }
+}
+#endif /* STORE_UNKNOWN_CHUNKS */
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+png_uint_32 PNGAPI
+png_permit_mng_features(png_structrp png_ptr, png_uint_32 mng_features)
+{
+   png_debug(1, "in png_permit_mng_features");
+
+   if (png_ptr == NULL)
+      return 0;
+
+   png_ptr->mng_features_permitted = mng_features & PNG_ALL_MNG_FEATURES;
+
+   return png_ptr->mng_features_permitted;
+}
+#endif
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+static unsigned int
+add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep)
+{
+   unsigned int i;
+
+   /* Utility function: update the 'keep' state of a chunk if it is already in
+    * the list, otherwise add it to the list.
+    */
+   for (i=0; i<count; ++i, list += 5)
+   {
+      if (memcmp(list, add, 4) == 0)
+      {
+         list[4] = (png_byte)keep;
+
+         return count;
+      }
+   }
+
+   if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
+   {
+      ++count;
+      memcpy(list, add, 4);
+      list[4] = (png_byte)keep;
+   }
+
+   return count;
+}
+
+void PNGAPI
+png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
+    png_const_bytep chunk_list, int num_chunks_in)
+{
+   png_bytep new_list;
+   unsigned int num_chunks, old_num_chunks;
+
+   if (png_ptr == NULL)
+      return;
+
+   if (keep < 0 || keep >= PNG_HANDLE_CHUNK_LAST)
+   {
+      png_app_error(png_ptr, "png_set_keep_unknown_chunks: invalid keep");
+
+      return;
+   }
+
+   if (num_chunks_in <= 0)
+   {
+      png_ptr->unknown_default = keep;
+
+      /* '0' means just set the flags, so stop here */
+      if (num_chunks_in == 0)
+        return;
+   }
+
+   if (num_chunks_in < 0)
+   {
+      /* Ignore all unknown chunks and all chunks recognized by
+       * libpng except for IHDR, PLTE, tRNS, IDAT, and IEND
+       */
+      static const png_byte chunks_to_ignore[] = {
+         98,  75,  71,  68, '\0',  /* bKGD */
+         99,  72,  82,  77, '\0',  /* cHRM */
+        101,  88,  73, 102, '\0',  /* eXIf */
+        103,  65,  77,  65, '\0',  /* gAMA */
+        104,  73,  83,  84, '\0',  /* hIST */
+        105,  67,  67,  80, '\0',  /* iCCP */
+        105,  84,  88, 116, '\0',  /* iTXt */
+        111,  70,  70, 115, '\0',  /* oFFs */
+        112,  67,  65,  76, '\0',  /* pCAL */
+        112,  72,  89, 115, '\0',  /* pHYs */
+        115,  66,  73,  84, '\0',  /* sBIT */
+        115,  67,  65,  76, '\0',  /* sCAL */
+        115,  80,  76,  84, '\0',  /* sPLT */
+        115,  84,  69,  82, '\0',  /* sTER */
+        115,  82,  71,  66, '\0',  /* sRGB */
+        116,  69,  88, 116, '\0',  /* tEXt */
+        116,  73,  77,  69, '\0',  /* tIME */
+        122,  84,  88, 116, '\0'   /* zTXt */
+      };
+
+      chunk_list = chunks_to_ignore;
+      num_chunks = (unsigned int)/*SAFE*/(sizeof chunks_to_ignore)/5U;
+   }
+
+   else /* num_chunks_in > 0 */
+   {
+      if (chunk_list == NULL)
+      {
+         /* Prior to 1.6.0 this was silently ignored, now it is an app_error
+          * which can be switched off.
+          */
+         png_app_error(png_ptr, "png_set_keep_unknown_chunks: no chunk list");
+
+         return;
+      }
+
+      num_chunks = (unsigned int)num_chunks_in;
+   }
+
+   old_num_chunks = png_ptr->num_chunk_list;
+   if (png_ptr->chunk_list == NULL)
+      old_num_chunks = 0;
+
+   /* Since num_chunks is always restricted to UINT_MAX/5 this can't overflow.
+    */
+   if (num_chunks + old_num_chunks > UINT_MAX/5)
+   {
+      png_app_error(png_ptr, "png_set_keep_unknown_chunks: too many chunks");
+
+      return;
+   }
+
+   /* If these chunks are being reset to the default then no more memory is
+    * required because add_one_chunk above doesn't extend the list if the 'keep'
+    * parameter is the default.
+    */
+   if (keep != 0)
+   {
+      new_list = png_voidcast(png_bytep, png_malloc(png_ptr,
+          5 * (num_chunks + old_num_chunks)));
+
+      if (old_num_chunks > 0)
+         memcpy(new_list, png_ptr->chunk_list, 5*old_num_chunks);
+   }
+
+   else if (old_num_chunks > 0)
+      new_list = png_ptr->chunk_list;
+
+   else
+      new_list = NULL;
+
+   /* Add the new chunks together with each one's handling code.  If the chunk
+    * already exists the code is updated, otherwise the chunk is added to the
+    * end.  (In libpng 1.6.0 order no longer matters because this code enforces
+    * the earlier convention that the last setting is the one that is used.)
+    */
+   if (new_list != NULL)
+   {
+      png_const_bytep inlist;
+      png_bytep outlist;
+      unsigned int i;
+
+      for (i=0; i<num_chunks; ++i)
+      {
+         old_num_chunks = add_one_chunk(new_list, old_num_chunks,
+             chunk_list+5*i, keep);
+      }
+
+      /* Now remove any spurious 'default' entries. */
+      num_chunks = 0;
+      for (i=0, inlist=outlist=new_list; i<old_num_chunks; ++i, inlist += 5)
+      {
+         if (inlist[4])
+         {
+            if (outlist != inlist)
+               memcpy(outlist, inlist, 5);
+            outlist += 5;
+            ++num_chunks;
+         }
+      }
+
+      /* This means the application has removed all the specialized handling. */
+      if (num_chunks == 0)
+      {
+         if (png_ptr->chunk_list != new_list)
+            png_free(png_ptr, new_list);
+
+         new_list = NULL;
+      }
+   }
+
+   else
+      num_chunks = 0;
+
+   png_ptr->num_chunk_list = num_chunks;
+
+   if (png_ptr->chunk_list != new_list)
+   {
+      if (png_ptr->chunk_list != NULL)
+         png_free(png_ptr, png_ptr->chunk_list);
+
+      png_ptr->chunk_list = new_list;
+   }
+}
+#endif
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+void PNGAPI
+png_set_read_user_chunk_fn(png_structrp png_ptr, png_voidp user_chunk_ptr,
+    png_user_chunk_ptr read_user_chunk_fn)
+{
+   png_debug(1, "in png_set_read_user_chunk_fn");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->read_user_chunk_fn = read_user_chunk_fn;
+   png_ptr->user_chunk_ptr = user_chunk_ptr;
+}
+#endif
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+void PNGAPI
+png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr,
+    png_bytepp row_pointers)
+{
+   png_debug(1, "in png_set_rows");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (info_ptr->row_pointers != NULL &&
+       (info_ptr->row_pointers != row_pointers))
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
+
+   info_ptr->row_pointers = row_pointers;
+
+   if (row_pointers != NULL)
+      info_ptr->valid |= PNG_INFO_IDAT;
+}
+#endif
+
+void PNGAPI
+png_set_compression_buffer_size(png_structrp png_ptr, size_t size)
+{
+   png_debug(1, "in png_set_compression_buffer_size");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (size == 0 || size > PNG_UINT_31_MAX)
+      png_error(png_ptr, "invalid compression buffer size");
+
+#  ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+   {
+      png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
+      return;
+   }
+#  endif
+
+#  ifdef PNG_WRITE_SUPPORTED
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+   {
+      if (png_ptr->zowner != 0)
+      {
+         png_warning(png_ptr,
+             "Compression buffer size cannot be changed because it is in use");
+
+         return;
+      }
+
+#ifndef __COVERITY__
+      /* Some compilers complain that this is always false.  However, it
+       * can be true when integer overflow happens.
+       */
+      if (size > ZLIB_IO_MAX)
+      {
+         png_warning(png_ptr,
+             "Compression buffer size limited to system maximum");
+         size = ZLIB_IO_MAX; /* must fit */
+      }
+#endif
+
+      if (size < 6)
+      {
+         /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH
+          * if this is permitted.
+          */
+         png_warning(png_ptr,
+             "Compression buffer size cannot be reduced below 6");
+
+         return;
+      }
+
+      if (png_ptr->zbuffer_size != size)
+      {
+         png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
+         png_ptr->zbuffer_size = (uInt)size;
+      }
+   }
+#  endif
+}
+
+void PNGAPI
+png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      info_ptr->valid &= (unsigned int)(~mask);
+}
+
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+/* This function was added to libpng 1.2.6 */
+void PNGAPI
+png_set_user_limits(png_structrp png_ptr, png_uint_32 user_width_max,
+    png_uint_32 user_height_max)
+{
+   png_debug(1, "in png_set_user_limits");
+
+   /* Images with dimensions larger than these limits will be
+    * rejected by png_set_IHDR().  To accept any PNG datastream
+    * regardless of dimensions, set both limits to 0x7fffffff.
+    */
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->user_width_max = user_width_max;
+   png_ptr->user_height_max = user_height_max;
+}
+
+/* This function was added to libpng 1.4.0 */
+void PNGAPI
+png_set_chunk_cache_max(png_structrp png_ptr, png_uint_32 user_chunk_cache_max)
+{
+   png_debug(1, "in png_set_chunk_cache_max");
+
+   if (png_ptr != NULL)
+      png_ptr->user_chunk_cache_max = user_chunk_cache_max;
+}
+
+/* This function was added to libpng 1.4.1 */
+void PNGAPI
+png_set_chunk_malloc_max(png_structrp png_ptr,
+    png_alloc_size_t user_chunk_malloc_max)
+{
+   png_debug(1, "in png_set_chunk_malloc_max");
+
+   if (png_ptr != NULL)
+      png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
+}
+#endif /* ?SET_USER_LIMITS */
+
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+void PNGAPI
+png_set_benign_errors(png_structrp png_ptr, int allowed)
+{
+   png_debug(1, "in png_set_benign_errors");
+
+   /* If allowed is 1, png_benign_error() is treated as a warning.
+    *
+    * If allowed is 0, png_benign_error() is treated as an error (which
+    * is the default behavior if png_set_benign_errors() is not called).
+    */
+
+   if (allowed != 0)
+      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN |
+         PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN;
+
+   else
+      png_ptr->flags &= ~(PNG_FLAG_BENIGN_ERRORS_WARN |
+         PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN);
+}
+#endif /* BENIGN_ERRORS */
+
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   /* Whether to report invalid palette index; added at libng-1.5.10.
+    * It is possible for an indexed (color-type==3) PNG file to contain
+    * pixels with invalid (out-of-range) indexes if the PLTE chunk has
+    * fewer entries than the image's bit-depth would allow. We recover
+    * from this gracefully by filling any incomplete palette with zeros
+    * (opaque black).  By default, when this occurs libpng will issue
+    * a benign error.  This API can be used to override that behavior.
+    */
+void PNGAPI
+png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
+{
+   png_debug(1, "in png_set_check_for_invalid_index");
+
+   if (allowed > 0)
+      png_ptr->num_palette_max = 0;
+
+   else
+      png_ptr->num_palette_max = -1;
+}
+#endif
+
+#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_pCAL_SUPPORTED) || \
+    defined(PNG_iCCP_SUPPORTED) || defined(PNG_sPLT_SUPPORTED)
+/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
+ * and if invalid, correct the keyword rather than discarding the entire
+ * chunk.  The PNG 1.0 specification requires keywords 1-79 characters in
+ * length, forbids leading or trailing whitespace, multiple internal spaces,
+ * and the non-break space (0x80) from ISO 8859-1.  Returns keyword length.
+ *
+ * The 'new_key' buffer must be 80 characters in size (for the keyword plus a
+ * trailing '\0').  If this routine returns 0 then there was no keyword, or a
+ * valid one could not be generated, and the caller must png_error.
+ */
+png_uint_32 /* PRIVATE */
+png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
+{
+#ifdef PNG_WARNINGS_SUPPORTED
+   png_const_charp orig_key = key;
+#endif
+   png_uint_32 key_len = 0;
+   int bad_character = 0;
+   int space = 1;
+
+   png_debug(1, "in png_check_keyword");
+
+   if (key == NULL)
+   {
+      *new_key = 0;
+      return 0;
+   }
+
+   while (*key && key_len < 79)
+   {
+      png_byte ch = (png_byte)*key++;
+
+      if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
+      {
+         *new_key++ = ch; ++key_len; space = 0;
+      }
+
+      else if (space == 0)
+      {
+         /* A space or an invalid character when one wasn't seen immediately
+          * before; output just a space.
+          */
+         *new_key++ = 32; ++key_len; space = 1;
+
+         /* If the character was not a space then it is invalid. */
+         if (ch != 32)
+            bad_character = ch;
+      }
+
+      else if (bad_character == 0)
+         bad_character = ch; /* just skip it, record the first error */
+   }
+
+   if (key_len > 0 && space != 0) /* trailing space */
+   {
+      --key_len; --new_key;
+      if (bad_character == 0)
+         bad_character = 32;
+   }
+
+   /* Terminate the keyword */
+   *new_key = 0;
+
+   if (key_len == 0)
+      return 0;
+
+#ifdef PNG_WARNINGS_SUPPORTED
+   /* Try to only output one warning per keyword: */
+   if (*key != 0) /* keyword too long */
+      png_warning(png_ptr, "keyword truncated");
+
+   else if (bad_character != 0)
+   {
+      PNG_WARNING_PARAMETERS(p)
+
+      png_warning_parameter(p, 1, orig_key);
+      png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character);
+
+      png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
+   }
+#else /* !WARNINGS */
+   PNG_UNUSED(png_ptr)
+#endif /* !WARNINGS */
+
+   return key_len;
+}
+#endif /* TEXT || pCAL || iCCP || sPLT */
+#endif /* READ || WRITE */
Index: /trunk/src/libs/libpng-1.6.45/pngstruct.h
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngstruct.h	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngstruct.h	(revision 107811)
@@ -0,0 +1,479 @@
+
+/* pngstruct.h - header file for PNG reference library
+ *
+ * Copyright (c) 2018-2022 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* The structure that holds the information to read and write PNG files.
+ * The only people who need to care about what is inside of this are the
+ * people who will be modifying the library for their own special needs.
+ * It should NOT be accessed directly by an application.
+ */
+
+#ifndef PNGSTRUCT_H
+#define PNGSTRUCT_H
+/* zlib.h defines the structure z_stream, an instance of which is included
+ * in this structure and is required for decompressing the LZ compressed
+ * data in PNG files.
+ */
+#ifndef ZLIB_CONST
+   /* We must ensure that zlib uses 'const' in declarations. */
+#  define ZLIB_CONST
+#endif
+#include "zlib.h"
+#ifdef const
+   /* zlib.h sometimes #defines const to nothing, undo this. */
+#  undef const
+#endif
+
+/* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
+ * with older builds.
+ */
+#if ZLIB_VERNUM < 0x1260
+#  define PNGZ_MSG_CAST(s) png_constcast(char*,s)
+#  define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b)
+#else
+#  define PNGZ_MSG_CAST(s) (s)
+#  define PNGZ_INPUT_CAST(b) (b)
+#endif
+
+/* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
+ * can handle at once.  This type need be no larger than 16 bits (so maximum of
+ * 65535), this define allows us to discover how big it is, but limited by the
+ * maximum for size_t.  The value can be overridden in a library build
+ * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
+ * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
+ * and may even improve performance on some systems (and degrade it on others.)
+ */
+#ifndef ZLIB_IO_MAX
+#  define ZLIB_IO_MAX ((uInt)-1)
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+/* The type of a compression buffer list used by the write code. */
+typedef struct png_compression_buffer
+{
+   struct png_compression_buffer *next;
+   png_byte                       output[1]; /* actually zbuf_size */
+} png_compression_buffer, *png_compression_bufferp;
+
+#define PNG_COMPRESSION_BUFFER_SIZE(pp)\
+   (offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)
+#endif
+
+/* Colorspace support; structures used in png_struct, png_info and in internal
+ * functions to hold and communicate information about the color space.
+ *
+ * PNG_COLORSPACE_SUPPORTED is only required if the application will perform
+ * colorspace corrections, otherwise all the colorspace information can be
+ * skipped and the size of libpng can be reduced (significantly) by compiling
+ * out the colorspace support.
+ */
+#ifdef PNG_COLORSPACE_SUPPORTED
+/* The chromaticities of the red, green and blue colorants and the chromaticity
+ * of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)).
+ */
+typedef struct png_xy
+{
+   png_fixed_point redx, redy;
+   png_fixed_point greenx, greeny;
+   png_fixed_point bluex, bluey;
+   png_fixed_point whitex, whitey;
+} png_xy;
+
+/* The same data as above but encoded as CIE XYZ values.  When this data comes
+ * from chromaticities the sum of the Y values is assumed to be 1.0
+ */
+typedef struct png_XYZ
+{
+   png_fixed_point red_X, red_Y, red_Z;
+   png_fixed_point green_X, green_Y, green_Z;
+   png_fixed_point blue_X, blue_Y, blue_Z;
+} png_XYZ;
+#endif /* COLORSPACE */
+
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+/* A colorspace is all the above plus, potentially, profile information;
+ * however at present libpng does not use the profile internally so it is only
+ * stored in the png_info struct (if iCCP is supported.)  The rendering intent
+ * is retained here and is checked.
+ *
+ * The file gamma encoding information is also stored here and gamma correction
+ * is done by libpng, whereas color correction must currently be done by the
+ * application.
+ */
+typedef struct png_colorspace
+{
+#ifdef PNG_GAMMA_SUPPORTED
+   png_fixed_point gamma;        /* File gamma */
+#endif
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+   png_xy      end_points_xy;    /* End points as chromaticities */
+   png_XYZ     end_points_XYZ;   /* End points as CIE XYZ colorant values */
+   png_uint_16 rendering_intent; /* Rendering intent of a profile */
+#endif
+
+   /* Flags are always defined to simplify the code. */
+   png_uint_16 flags;            /* As defined below */
+} png_colorspace, * PNG_RESTRICT png_colorspacerp;
+
+typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
+
+/* General flags for the 'flags' field */
+#define PNG_COLORSPACE_HAVE_GAMMA           0x0001
+#define PNG_COLORSPACE_HAVE_ENDPOINTS       0x0002
+#define PNG_COLORSPACE_HAVE_INTENT          0x0004
+#define PNG_COLORSPACE_FROM_gAMA            0x0008
+#define PNG_COLORSPACE_FROM_cHRM            0x0010
+#define PNG_COLORSPACE_FROM_sRGB            0x0020
+#define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
+#define PNG_COLORSPACE_MATCHES_sRGB         0x0080 /* exact match on profile */
+#define PNG_COLORSPACE_INVALID              0x8000
+#define PNG_COLORSPACE_CANCEL(flags)        (0xffff ^ (flags))
+#endif /* COLORSPACE || GAMMA */
+
+struct png_struct_def
+{
+#ifdef PNG_SETJMP_SUPPORTED
+   jmp_buf jmp_buf_local;     /* New name in 1.6.0 for jmp_buf in png_struct */
+   png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
+   jmp_buf *jmp_buf_ptr;      /* passed to longjmp_fn */
+   size_t jmp_buf_size;       /* size of the above, if allocated */
+#endif
+   png_error_ptr error_fn;    /* function for printing errors and aborting */
+#ifdef PNG_WARNINGS_SUPPORTED
+   png_error_ptr warning_fn;  /* function for printing warnings */
+#endif
+   png_voidp error_ptr;       /* user supplied struct for error functions */
+   png_rw_ptr write_data_fn;  /* function for writing output data */
+   png_rw_ptr read_data_fn;   /* function for reading input data */
+   png_voidp io_ptr;          /* ptr to application struct for I/O functions */
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   png_user_transform_ptr read_user_transform_fn; /* user read transform */
+#endif
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+   png_user_transform_ptr write_user_transform_fn; /* user write transform */
+#endif
+
+/* These were added in libpng-1.0.2 */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+   png_voidp user_transform_ptr; /* user supplied struct for user transform */
+   png_byte user_transform_depth;    /* bit depth of user transformed pixels */
+   png_byte user_transform_channels; /* channels in user transformed pixels */
+#endif
+#endif
+
+   png_uint_32 mode;          /* tells us where we are in the PNG file */
+   png_uint_32 flags;         /* flags indicating various things to libpng */
+   png_uint_32 transformations; /* which transformations to perform */
+
+   png_uint_32 zowner;        /* ID (chunk type) of zstream owner, 0 if none */
+   z_stream    zstream;       /* decompression structure */
+
+#ifdef PNG_WRITE_SUPPORTED
+   png_compression_bufferp zbuffer_list; /* Created on demand during write */
+   uInt                    zbuffer_size; /* size of the actual buffer */
+
+   int zlib_level;            /* holds zlib compression level */
+   int zlib_method;           /* holds zlib compression method */
+   int zlib_window_bits;      /* holds zlib compression window bits */
+   int zlib_mem_level;        /* holds zlib compression memory level */
+   int zlib_strategy;         /* holds zlib compression strategy */
+#endif
+/* Added at libpng 1.5.4 */
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+   int zlib_text_level;            /* holds zlib compression level */
+   int zlib_text_method;           /* holds zlib compression method */
+   int zlib_text_window_bits;      /* holds zlib compression window bits */
+   int zlib_text_mem_level;        /* holds zlib compression memory level */
+   int zlib_text_strategy;         /* holds zlib compression strategy */
+#endif
+/* End of material added at libpng 1.5.4 */
+/* Added at libpng 1.6.0 */
+#ifdef PNG_WRITE_SUPPORTED
+   int zlib_set_level;        /* Actual values set into the zstream on write */
+   int zlib_set_method;
+   int zlib_set_window_bits;
+   int zlib_set_mem_level;
+   int zlib_set_strategy;
+#endif
+
+   png_uint_32 width;         /* width of image in pixels */
+   png_uint_32 height;        /* height of image in pixels */
+   png_uint_32 num_rows;      /* number of rows in current pass */
+   png_uint_32 usr_width;     /* width of row at start of write */
+   size_t rowbytes;           /* size of row in bytes */
+   png_uint_32 iwidth;        /* width of current interlaced row in pixels */
+   png_uint_32 row_number;    /* current row in interlace pass */
+   png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
+   png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
+                               * While reading this is a pointer into
+                               * big_prev_row; while writing it is separately
+                               * allocated if needed.
+                               */
+   png_bytep row_buf;         /* buffer to save current (unfiltered) row.
+                               * While reading, this is a pointer into
+                               * big_row_buf; while writing it is separately
+                               * allocated.
+                               */
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   png_bytep try_row;    /* buffer to save trial row when filtering */
+   png_bytep tst_row;    /* buffer to save best trial row when filtering */
+#endif
+   size_t info_rowbytes;      /* Added in 1.5.4: cache of updated row bytes */
+
+   png_uint_32 idat_size;     /* current IDAT size for read */
+   png_uint_32 crc;           /* current chunk CRC value */
+   png_colorp palette;        /* palette from the input file */
+   png_uint_16 num_palette;   /* number of color entries in palette */
+
+/* Added at libpng-1.5.10 */
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   int num_palette_max;       /* maximum palette index found in IDAT */
+#endif
+
+   png_uint_16 num_trans;     /* number of transparency values */
+   png_byte compression;      /* file compression type (always 0) */
+   png_byte filter;           /* file filter type (always 0) */
+   png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
+   png_byte pass;             /* current interlace pass (0 - 6) */
+   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ in png.h ) */
+   png_byte color_type;       /* color type of file */
+   png_byte bit_depth;        /* bit depth of file */
+   png_byte usr_bit_depth;    /* bit depth of users row: write only */
+   png_byte pixel_depth;      /* number of bits per pixel */
+   png_byte channels;         /* number of channels in file */
+#ifdef PNG_WRITE_SUPPORTED
+   png_byte usr_channels;     /* channels at start of write: write only */
+#endif
+   png_byte sig_bytes;        /* magic bytes read/written from start of file */
+   png_byte maximum_pixel_depth;
+                              /* pixel depth used for the row buffers */
+   png_byte transformed_pixel_depth;
+                              /* pixel depth after read/write transforms */
+#if ZLIB_VERNUM >= 0x1240
+   png_byte zstream_start;    /* at start of an input zlib stream */
+#endif /* Zlib >= 1.2.4 */
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+   png_uint_16 filler;           /* filler bytes for pixel expansion */
+#endif
+
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+   png_byte background_gamma_type;
+   png_fixed_point background_gamma;
+   png_color_16 background;   /* background color in screen gamma space */
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   png_color_16 background_1; /* background normalized to gamma 1.0 */
+#endif
+#endif /* bKGD */
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+   png_flush_ptr output_flush_fn; /* Function for flushing output */
+   png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
+   png_uint_32 flush_rows;    /* number of rows written since last flush */
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
+   png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
+
+   png_bytep gamma_table;     /* gamma table for 8-bit depth files */
+   png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+   png_bytep gamma_from_1;    /* converts from 1.0 to screen */
+   png_bytep gamma_to_1;      /* converts from file to 1.0 */
+   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
+   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
+   png_color_8 sig_bit;       /* significant bits in each available channel */
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+   png_color_8 shift;         /* shift for significant bit transformation */
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
+ || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_bytep trans_alpha;           /* alpha values for paletted files */
+   png_color_16 trans_color;  /* transparent color for non-paletted files */
+#endif
+
+   png_read_status_ptr read_row_fn;   /* called after each row is decoded */
+   png_write_status_ptr write_row_fn; /* called after each row is encoded */
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+   png_progressive_info_ptr info_fn; /* called after header data fully read */
+   png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
+   png_progressive_end_ptr end_fn;   /* called after image is complete */
+   png_bytep save_buffer_ptr;        /* current location in save_buffer */
+   png_bytep save_buffer;            /* buffer for previously read data */
+   png_bytep current_buffer_ptr;     /* current location in current_buffer */
+   png_bytep current_buffer;         /* buffer for recently used data */
+   png_uint_32 push_length;          /* size of current input chunk */
+   png_uint_32 skip_length;          /* bytes to skip in input data */
+   size_t save_buffer_size;          /* amount of data now in save_buffer */
+   size_t save_buffer_max;           /* total size of save_buffer */
+   size_t buffer_size;               /* total amount of available input data */
+   size_t current_buffer_size;       /* amount of data now in current_buffer */
+   int process_mode;                 /* what push library is currently doing */
+   int cur_palette;                  /* current push library palette index */
+#endif /* PROGRESSIVE_READ */
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   png_bytep palette_lookup; /* lookup table for quantizing */
+   png_bytep quantize_index; /* index translation for palette files */
+#endif
+
+/* Options */
+#ifdef PNG_SET_OPTION_SUPPORTED
+   png_uint_32 options;           /* On/off state (up to 16 options) */
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng-1.7 */
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+   char time_buffer[29]; /* String to hold RFC 1123 time text */
+#endif
+#endif
+
+/* New members added in libpng-1.0.6 */
+
+   png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+   png_voidp user_chunk_ptr;
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
+#endif
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   int          unknown_default; /* As PNG_HANDLE_* */
+   unsigned int num_chunk_list;  /* Number of entries in the list */
+   png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
+                                  * followed by a PNG_HANDLE_* byte */
+#endif
+
+/* New members added in libpng-1.0.3 */
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   png_byte rgb_to_gray_status;
+   /* Added in libpng 1.5.5 to record setting of coefficients: */
+   png_byte rgb_to_gray_coefficients_set;
+   /* These were changed from png_byte in libpng-1.0.6 */
+   png_uint_16 rgb_to_gray_red_coeff;
+   png_uint_16 rgb_to_gray_green_coeff;
+   /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
+#endif
+
+/* New member added in libpng-1.6.36 */
+#if defined(PNG_READ_EXPAND_SUPPORTED) && \
+    defined(PNG_ARM_NEON_IMPLEMENTATION)
+   png_bytep riffled_palette; /* buffer for accelerated palette expansion */
+#endif
+
+/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+/* Changed from png_byte to png_uint_32 at version 1.2.0 */
+   png_uint_32 mng_features_permitted;
+#endif
+
+/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   png_byte filter_type;
+#endif
+
+/* New members added in libpng-1.2.0 */
+
+/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_voidp mem_ptr;             /* user supplied struct for mem functions */
+   png_malloc_ptr malloc_fn;      /* function for allocating memory */
+   png_free_ptr free_fn;          /* function for freeing memory */
+#endif
+
+/* New member added in libpng-1.0.13 and 1.2.0 */
+   png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* The following three members were added at version 1.0.14 and 1.2.4 */
+   png_bytep quantize_sort;          /* working sort array */
+   png_bytep index_to_palette;       /* where the original index currently is
+                                        in the palette */
+   png_bytep palette_to_index;       /* which original index points to this
+                                         palette color */
+#endif
+
+/* New members added in libpng-1.0.16 and 1.2.6 */
+   png_byte compression_type;
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+   png_uint_32 user_width_max;
+   png_uint_32 user_height_max;
+
+   /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
+    * chunks that can be stored (0 means unlimited).
+    */
+   png_uint_32 user_chunk_cache_max;
+
+   /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
+    * can occupy when decompressed.  0 means unlimited.
+    */
+   png_alloc_size_t user_chunk_malloc_max;
+#endif
+
+/* New member added in libpng-1.0.25 and 1.2.17 */
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+   /* Temporary storage for unknown chunk that the library doesn't recognize,
+    * used while reading the chunk.
+    */
+   png_unknown_chunk unknown_chunk;
+#endif
+
+/* New member added in libpng-1.2.26 */
+   size_t old_big_row_buf_size;
+
+#ifdef PNG_READ_SUPPORTED
+/* New member added in libpng-1.2.30 */
+  png_bytep        read_buffer;      /* buffer for reading chunk data */
+  png_alloc_size_t read_buffer_size; /* current size of the buffer */
+#endif
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+  uInt             IDAT_read_size;   /* limit on read buffer size for IDAT */
+#endif
+
+#ifdef PNG_IO_STATE_SUPPORTED
+/* New member added in libpng-1.4.0 */
+   png_uint_32 io_state;
+#endif
+
+/* New member added in libpng-1.5.6 */
+   png_bytep big_prev_row;
+
+/* New member added in libpng-1.5.7 */
+   void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
+      png_bytep row, png_const_bytep prev_row);
+
+#ifdef PNG_READ_SUPPORTED
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+   png_colorspace   colorspace;
+#endif
+#endif
+};
+#endif /* PNGSTRUCT_H */
Index: /trunk/src/libs/libpng-1.6.45/pngtest.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngtest.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngtest.c	(revision 107811)
@@ -0,0 +1,2107 @@
+
+/* pngtest.c - a test program for libpng
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This program reads in a PNG image, writes it out again, and then
+ * compares the two files.  If the files are identical, this shows that
+ * the basic chunk handling, filtering, and (de)compression code is working
+ * properly.  It does not currently test all of the transforms, although
+ * it probably should.
+ *
+ * The program will report "FAIL" in certain legitimate cases:
+ * 1) when the compression level or filter selection method is changed.
+ * 2) when the maximum IDAT size (PNG_ZBUF_SIZE in pngconf.h) is not 8192.
+ * 3) unknown unsafe-to-copy ancillary chunks or unknown critical chunks
+ *    exist in the input file.
+ * 4) others not listed here...
+ * In these cases, it is best to check with another tool such as "pngcheck"
+ * to see what the differences between the two files are.
+ *
+ * If a filename is given on the command-line, then this file is used
+ * for the input, rather than the default "pngtest.png".  This allows
+ * testing a wide variety of files easily.  You can also test a number
+ * of files at once by typing "pngtest -m file1.png file2.png ..."
+ */
+
+#define _POSIX_SOURCE 1
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef PNG_ZLIB_HEADER
+#  include PNG_ZLIB_HEADER /* defined by pnglibconf.h from 1.7 */
+#else
+#  include <zlib.h>
+#endif
+
+#include "png.h"
+
+/* Generate a compiler error if there is an old png.h in the search path. */
+typedef png_libpng_version_1_6_43 Your_png_h_is_not_version_1_6_43;
+
+/* Ensure that all version numbers in png.h are consistent with one another. */
+#if (PNG_LIBPNG_VER != PNG_LIBPNG_VER_MAJOR * 10000 + \
+                       PNG_LIBPNG_VER_MINOR * 100 + \
+                       PNG_LIBPNG_VER_RELEASE) || \
+    (PNG_LIBPNG_VER_SHAREDLIB != PNG_LIBPNG_VER_MAJOR * 10 + \
+                                 PNG_LIBPNG_VER_MINOR) || \
+    (PNG_LIBPNG_VER_SHAREDLIB != PNG_LIBPNG_VER_SONUM) || \
+    (PNG_LIBPNG_VER_SHAREDLIB != PNG_LIBPNG_VER_DLLNUM)
+#  error "Inconsistent version numbers in png.h"
+#endif
+
+/* In version 1.6.1, we added support for the configure test harness, which
+ * uses 77 to indicate a skipped test. On the other hand, in cmake build tests,
+ * we still need to succeed on a skipped test, so:
+ */
+#if defined(HAVE_CONFIG_H)
+#  define SKIP 77
+#else
+#  define SKIP 0
+#endif
+
+/* Known chunks that exist in pngtest.png must be supported, or pngtest will
+ * fail simply as a result of re-ordering them.  This may be fixed in the next
+ * generation of libpng.
+ *
+ * pngtest allocates a single row buffer for each row and overwrites it,
+ * therefore if the write side doesn't support the writing of interlaced images
+ * nothing can be done for an interlaced image (and the code below will fail
+ * horribly trying to write extra data after writing garbage).
+ */
+#if defined PNG_READ_SUPPORTED && /* else nothing can be done */ \
+    defined PNG_READ_bKGD_SUPPORTED && \
+    defined PNG_READ_cHRM_SUPPORTED && \
+    defined PNG_READ_gAMA_SUPPORTED && \
+    defined PNG_READ_oFFs_SUPPORTED && \
+    defined PNG_READ_pCAL_SUPPORTED && \
+    defined PNG_READ_pHYs_SUPPORTED && \
+    defined PNG_READ_sBIT_SUPPORTED && \
+    defined PNG_READ_sCAL_SUPPORTED && \
+    defined PNG_READ_sRGB_SUPPORTED && \
+    defined PNG_READ_sPLT_SUPPORTED && \
+    defined PNG_READ_tEXt_SUPPORTED && \
+    defined PNG_READ_tIME_SUPPORTED && \
+    defined PNG_READ_zTXt_SUPPORTED && \
+    (defined PNG_WRITE_INTERLACING_SUPPORTED || PNG_LIBPNG_VER >= 10700)
+
+/* Copied from pngpriv.h but only used in error messages below. */
+#ifndef PNG_ZBUF_SIZE
+#  define PNG_ZBUF_SIZE 8192
+#endif
+
+#ifndef PNG_STDIO_SUPPORTED
+typedef FILE * png_FILE_p;
+#endif
+
+/* This hack was introduced for historical reasons, and we are
+ * still keeping it in libpng-1.6.x for compatibility reasons.
+ */
+#define STDERR stdout
+
+#ifndef PNG_DEBUG
+#  define PNG_DEBUG 0
+#endif
+
+#if PNG_DEBUG > 1
+#  define pngtest_debug(m)          ((void)fprintf(stderr, m "\n"))
+#  define pngtest_debug1(m, p1)     ((void)fprintf(stderr, m "\n", p1))
+#  define pngtest_debug2(m, p1, p2) ((void)fprintf(stderr, m "\n", p1, p2))
+#elif PNG_DEBUG == 0 || PNG_DEBUG == 1
+#  define pngtest_debug(m)          ((void)0)
+#  define pngtest_debug1(m, p1)     ((void)0)
+#  define pngtest_debug2(m, p1, p2) ((void)0)
+#else /* PNG_DEBUG < 0 */
+#  error "Bad PNG_DEBUG value"
+#endif
+
+/* Turn on CPU timing
+#define PNGTEST_TIMING
+*/
+
+#ifndef PNG_FLOATING_POINT_SUPPORTED
+#undef PNGTEST_TIMING
+#endif
+
+#ifdef PNGTEST_TIMING
+static float t_start, t_stop, t_decode, t_encode, t_misc;
+#include <time.h>
+#endif
+
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+static int tIME_chunk_present = 0;
+static char tIME_string[29] = "tIME chunk is not present";
+/* This use case is deprecated.
+ * See the declaration of png_convert_to_rfc1123_buffer for more details.
+ */
+#endif
+
+static int verbose = 0;
+static int strict = 0;
+static int relaxed = 0;
+static int xfail = 0;
+static int unsupported_chunks = 0; /* chunk unsupported by libpng in input */
+static int error_count = 0; /* count calls to png_error */
+static int warning_count = 0; /* count calls to png_warning */
+
+/* Example of using row callbacks to make a simple progress meter */
+static int status_pass = 1;
+static int status_dots_requested = 0;
+static int status_dots = 1;
+
+static void PNGCBAPI
+read_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
+{
+   /* The callback should always receive correct parameters. */
+   if (png_ptr == NULL)
+      png_error(png_ptr, "read_row_callback: bad png_ptr");
+   if (row_number > PNG_UINT_31_MAX)
+      png_error(png_ptr, "read_row_callback: bad row number");
+   if (pass < 0 || pass > 7)
+      png_error(png_ptr, "read_row_callback: bad pass");
+
+   if (status_pass != pass)
+   {
+      fprintf(stdout, "\n Pass %d: ", pass);
+      status_pass = pass;
+      status_dots = 31;
+   }
+
+   status_dots--;
+
+   if (status_dots == 0)
+   {
+      fprintf(stdout, "\n         ");
+      status_dots = 30;
+   }
+
+   fprintf(stdout, "r");
+}
+
+#ifdef PNG_WRITE_SUPPORTED
+static void PNGCBAPI
+write_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
+{
+   /* The callback should always receive correct parameters. */
+   if (png_ptr == NULL)
+      png_error(png_ptr, "write_row_callback: bad png_ptr");
+   if (row_number > PNG_UINT_31_MAX)
+      png_error(png_ptr, "write_row_callback: bad row number");
+   if (pass < 0 || pass > 7)
+      png_error(png_ptr, "write_row_callback: bad pass");
+
+   fprintf(stdout, "w");
+}
+#endif
+
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+/* Example of using a user transform callback (doesn't do anything at present).
+ */
+static void PNGCBAPI
+read_user_callback(png_structp png_ptr, png_row_infop row_info, png_bytep data)
+{
+   /* The callback should always receive correct parameters. */
+   if (png_ptr == NULL)
+      png_error(png_ptr, "read_user_callback: bad png_ptr");
+   if (row_info == NULL)
+      png_error(png_ptr, "read_user_callback: bad row info");
+   if (data == NULL)
+      png_error(png_ptr, "read_user_callback: bad data");
+}
+#endif
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+/* Example of using user transform callback (we don't transform anything,
+ * but merely count the zero samples)
+ */
+
+static png_uint_32 zero_samples;
+
+static void PNGCBAPI
+count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data)
+{
+   png_bytep dp = data;
+
+   /* The callback should always receive correct parameters. */
+   if (png_ptr == NULL)
+      png_error(png_ptr, "count_zero_samples: bad png_ptr");
+   if (row_info == NULL)
+      png_error(png_ptr, "count_zero_samples: bad row info");
+   if (data == NULL)
+      png_error(png_ptr, "count_zero_samples: bad data");
+
+   /* Contents of row_info:
+    *  png_uint_32 width      width of row
+    *  png_uint_32 rowbytes   number of bytes in row
+    *  png_byte color_type    color type of pixels
+    *  png_byte bit_depth     bit depth of samples
+    *  png_byte channels      number of channels (1-4)
+    *  png_byte pixel_depth   bits per pixel (depth*channels)
+    */
+
+   /* Counts the number of zero samples (or zero pixels if color_type is 3 */
+
+   if (row_info->color_type == 0 || row_info->color_type == 3)
+   {
+      int pos = 0;
+      png_uint_32 n, nstop;
+
+      for (n = 0, nstop = row_info->width; n < nstop; n++)
+      {
+         if (row_info->bit_depth == 1)
+         {
+            if (((*dp << pos++ ) & 0x80) == 0)
+               zero_samples++;
+
+            if (pos == 8)
+            {
+               pos = 0;
+               dp++;
+            }
+         }
+
+         if (row_info->bit_depth == 2)
+         {
+            if (((*dp << (pos+=2)) & 0xc0) == 0)
+               zero_samples++;
+
+            if (pos == 8)
+            {
+               pos = 0;
+               dp++;
+            }
+         }
+
+         if (row_info->bit_depth == 4)
+         {
+            if (((*dp << (pos+=4)) & 0xf0) == 0)
+               zero_samples++;
+
+            if (pos == 8)
+            {
+               pos = 0;
+               dp++;
+            }
+         }
+
+         if (row_info->bit_depth == 8)
+            if (*dp++ == 0)
+               zero_samples++;
+
+         if (row_info->bit_depth == 16)
+         {
+            if ((*dp | *(dp+1)) == 0)
+               zero_samples++;
+            dp += 2;
+         }
+      }
+   }
+   else /* Other color types */
+   {
+      png_uint_32 n, nstop;
+      int channel;
+      int color_channels = row_info->channels;
+      if (row_info->color_type > 3)
+         color_channels--;
+
+      for (n = 0, nstop = row_info->width; n < nstop; n++)
+      {
+         for (channel = 0; channel < color_channels; channel++)
+         {
+            if (row_info->bit_depth == 8)
+               if (*dp++ == 0)
+                  zero_samples++;
+
+            if (row_info->bit_depth == 16)
+            {
+               if ((*dp | *(dp+1)) == 0)
+                  zero_samples++;
+
+               dp += 2;
+            }
+         }
+         if (row_info->color_type > 3)
+         {
+            dp++;
+            if (row_info->bit_depth == 16)
+               dp++;
+         }
+      }
+   }
+}
+#endif /* WRITE_USER_TRANSFORM */
+
+#ifndef PNG_STDIO_SUPPORTED
+/* START of code to validate stdio-free compilation */
+/* These copies of the default read/write functions come from pngrio.c and
+ * pngwio.c.  They allow "don't include stdio" testing of the library.
+ * This is the function that does the actual reading of data.  If you are
+ * not reading from a standard C stream, you should create a replacement
+ * read_data function and use it at run time with png_set_read_fn(), rather
+ * than changing the library.
+ */
+
+#ifdef PNG_IO_STATE_SUPPORTED
+void
+pngtest_check_io_state(png_structp png_ptr, size_t data_length,
+    png_uint_32 io_op)
+{
+   png_uint_32 io_state = png_get_io_state(png_ptr);
+   int err = 0;
+
+   /* Check if the current operation (reading / writing) is as expected. */
+   if ((io_state & PNG_IO_MASK_OP) != io_op)
+      png_error(png_ptr, "Incorrect operation in I/O state");
+
+   /* Check if the buffer size specific to the current location
+    * (file signature / header / data / crc) is as expected.
+    */
+   switch ((io_state & PNG_IO_MASK_LOC) != 0)
+   {
+   case PNG_IO_SIGNATURE:
+      if (data_length > 8)
+         err = 1;
+      break;
+   case PNG_IO_CHUNK_HDR:
+      if (data_length != 8)
+         err = 1;
+      break;
+   case PNG_IO_CHUNK_DATA:
+      break;  /* no restrictions here */
+   case PNG_IO_CHUNK_CRC:
+      if (data_length != 4)
+         err = 1;
+      break;
+   default:
+      err = 1;  /* uninitialized */
+   }
+   if (err != 0)
+      png_error(png_ptr, "Bad I/O state or buffer size");
+}
+#endif
+
+static void PNGCBAPI
+pngtest_read_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check = 0;
+   png_voidp io_ptr;
+
+   if (png_ptr == NULL)
+      png_error(png_ptr, "pngtest_read_data: bad png_ptr");
+
+   /* fread() returns 0 on error, so it is OK to store this in a size_t
+    * instead of an int, which is what fread() actually returns.
+    */
+   io_ptr = png_get_io_ptr(png_ptr);
+   if (io_ptr != NULL)
+      check = fread(data, 1, length, (png_FILE_p)io_ptr);
+
+   if (check != length)
+      png_error(png_ptr, "Read Error");
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   pngtest_check_io_state(png_ptr, length, PNG_IO_READING);
+#endif
+}
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+static void PNGCBAPI
+pngtest_flush(png_structp png_ptr)
+{
+   if (png_ptr == NULL)
+      png_error(png_ptr, "pngtest_flush: bad png_ptr");
+
+   /* Do nothing; fflush() is said to be just a waste of energy. */
+}
+#endif
+
+/* This is the function that does the actual writing of data.  If you are
+ * not writing to a standard C stream, you should create a replacement
+ * write_data function and use it at run time with png_set_write_fn(), rather
+ * than changing the library.
+ */
+static void PNGCBAPI
+pngtest_write_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check;
+
+   if (png_ptr == NULL)
+      png_error(png_ptr, "pngtest_write_data: bad png_ptr");
+
+   check = fwrite(data, 1, length, (png_FILE_p)png_get_io_ptr(png_ptr));
+
+   if (check != length)
+      png_error(png_ptr, "Write Error");
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   pngtest_check_io_state(png_ptr, length, PNG_IO_WRITING);
+#endif
+}
+#endif /* !STDIO */
+
+/* This function is called when there is a warning, but the library thinks
+ * it can continue anyway.  Replacement functions don't have to do anything
+ * here if you don't want to.  In the default configuration, png_ptr is
+ * not used, but it is passed in case it may be useful.
+ */
+typedef struct
+{
+   const char *file_name;
+}  pngtest_error_parameters;
+
+static void PNGCBAPI
+pngtest_warning(png_structp png_ptr, png_const_charp message)
+{
+   const char *name = "UNKNOWN (ERROR!)";
+   pngtest_error_parameters *test =
+      (pngtest_error_parameters*)png_get_error_ptr(png_ptr);
+
+   ++warning_count;
+
+   if (test != NULL && test->file_name != NULL)
+      name = test->file_name;
+
+   fprintf(STDERR, "\n%s: libpng warning: %s\n", name, message);
+}
+
+/* This is the default error handling function.  Note that replacements for
+ * this function MUST NOT RETURN, or the program will likely crash.  This
+ * function is used by default, or if the program supplies NULL for the
+ * error function pointer in png_set_error_fn().
+ */
+static void PNGCBAPI
+pngtest_error(png_structp png_ptr, png_const_charp message)
+{
+   ++error_count;
+
+   pngtest_warning(png_ptr, message);
+   /* We can return because png_error calls the default handler, which is
+    * actually OK in this case.
+    */
+}
+
+/* END of code to validate stdio-free compilation */
+
+/* START of code to validate memory allocation and deallocation */
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+
+/* Allocate memory.  For reasonable files, size should never exceed
+ * 64K.  However, zlib may allocate more than 64K if you don't tell
+ * it not to.  See zconf.h and png.h for more information.  zlib does
+ * need to allocate exactly 64K, so whatever you call here must
+ * have the ability to do that.
+ *
+ * This piece of code can be compiled to validate max 64K allocations
+ * by setting MAXSEG_64K in zlib zconf.h *or* PNG_MAX_MALLOC_64K.
+ */
+typedef struct memory_information
+{
+   png_alloc_size_t          size;
+   png_voidp                 pointer;
+   struct memory_information *next;
+} memory_information;
+typedef memory_information *memory_infop;
+
+static memory_infop pinformation = NULL;
+static int current_allocation = 0;
+static int maximum_allocation = 0;
+static int total_allocation = 0;
+static int num_allocations = 0;
+
+png_voidp PNGCBAPI png_debug_malloc PNGARG((png_structp png_ptr,
+    png_alloc_size_t size));
+void PNGCBAPI png_debug_free PNGARG((png_structp png_ptr, png_voidp ptr));
+
+png_voidp
+PNGCBAPI png_debug_malloc(png_structp png_ptr, png_alloc_size_t size)
+{
+
+   /* png_malloc has already tested for NULL; png_create_struct calls
+    * png_debug_malloc directly, with png_ptr == NULL which is OK
+    */
+
+   if (size == 0)
+      return NULL;
+
+   /* This calls the library allocator twice, once to get the requested
+      buffer and once to get a new free list entry. */
+   {
+      /* Disable malloc_fn and free_fn */
+      memory_infop pinfo;
+      png_set_mem_fn(png_ptr, NULL, NULL, NULL);
+      pinfo = (memory_infop)png_malloc(png_ptr,
+          (sizeof *pinfo));
+      pinfo->size = size;
+      current_allocation += size;
+      total_allocation += size;
+      ++num_allocations;
+
+      if (current_allocation > maximum_allocation)
+         maximum_allocation = current_allocation;
+
+      pinfo->pointer = png_malloc(png_ptr, size);
+      /* Restore malloc_fn and free_fn */
+
+      png_set_mem_fn(png_ptr,
+          NULL, png_debug_malloc, png_debug_free);
+
+      if (size != 0 && pinfo->pointer == NULL)
+      {
+         current_allocation -= size;
+         total_allocation -= size;
+         png_error(png_ptr,
+           "out of memory in pngtest->png_debug_malloc");
+      }
+
+      pinfo->next = pinformation;
+      pinformation = pinfo;
+      /* Make sure the caller isn't assuming zeroed memory. */
+      memset(pinfo->pointer, 0xdd, pinfo->size);
+
+      if (verbose != 0)
+         printf("png_malloc %lu bytes at %p\n", (unsigned long)size,
+             pinfo->pointer);
+
+      return (png_voidp)pinfo->pointer;
+   }
+}
+
+/* Free a pointer.  It is removed from the list at the same time. */
+void PNGCBAPI
+png_debug_free(png_structp png_ptr, png_voidp ptr)
+{
+   if (png_ptr == NULL)
+      fprintf(STDERR, "NULL pointer to png_debug_free.\n");
+
+   if (ptr == 0)
+   {
+#if 0 /* This happens all the time. */
+      fprintf(STDERR, "WARNING: freeing NULL pointer\n");
+#endif
+      return;
+   }
+
+   /* Unlink the element from the list. */
+   if (pinformation != NULL)
+   {
+      memory_infop *ppinfo = &pinformation;
+
+      for (;;)
+      {
+         memory_infop pinfo = *ppinfo;
+
+         if (pinfo->pointer == ptr)
+         {
+            *ppinfo = pinfo->next;
+            current_allocation -= pinfo->size;
+            if (current_allocation < 0)
+               fprintf(STDERR, "Duplicate free of memory\n");
+            /* We must free the list element too, but first kill
+               the memory that is to be freed. */
+            memset(ptr, 0x55, pinfo->size);
+            free(pinfo);
+            pinfo = NULL;
+            break;
+         }
+
+         if (pinfo->next == NULL)
+         {
+            fprintf(STDERR, "Pointer %p not found\n", ptr);
+            break;
+         }
+
+         ppinfo = &pinfo->next;
+      }
+   }
+
+   /* Finally free the data. */
+   if (verbose != 0)
+      printf("Freeing %p\n", ptr);
+
+   if (ptr != NULL)
+      free(ptr);
+   ptr = NULL;
+}
+#endif /* USER_MEM && DEBUG */
+/* END of code to test memory allocation/deallocation */
+
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+/* Demonstration of user chunk support of the sTER and vpAg chunks */
+
+/* (sTER is a public chunk not yet known by libpng.  vpAg is a private
+chunk used in ImageMagick to store "virtual page" size).  */
+
+typedef struct user_chunk_info_def
+{
+   png_const_infop info_ptr;
+   png_uint_32     vpAg_width, vpAg_height;
+   png_byte        vpAg_units;
+   png_byte        sTER_mode;
+   int             location[2];
+} user_chunk_info;
+
+/* Used for location and order; zero means nothing. */
+#define have_sTER   0x01
+#define have_vpAg   0x02
+#define before_PLTE 0x10
+#define before_IDAT 0x20
+#define after_IDAT  0x40
+
+static void
+init_user_chunk_info(png_const_infop info_ptr, user_chunk_info *chunk_data)
+{
+   memset(chunk_data, 0, sizeof(*chunk_data));
+   chunk_data->info_ptr = info_ptr;
+}
+
+static int
+set_chunk_location(png_structp png_ptr, user_chunk_info *chunk_data, int what)
+{
+   int location;
+
+   if ((chunk_data->location[0] & what) != 0 ||
+       (chunk_data->location[1] & what) != 0)
+      return 0; /* we already have one of these */
+
+   /* Find where we are (the code below zeroes info_ptr to indicate that the
+    * chunks before the first IDAT have been read.)
+    */
+   if (chunk_data->info_ptr == NULL) /* after IDAT */
+      location = what | after_IDAT;
+
+   else if (png_get_valid(png_ptr, chunk_data->info_ptr, PNG_INFO_PLTE) != 0)
+      location = what | before_IDAT;
+
+   else
+      location = what | before_PLTE;
+
+   if (chunk_data->location[0] == 0)
+      chunk_data->location[0] = location;
+
+   else
+      chunk_data->location[1] = location;
+
+   return 1; /* handled */
+}
+
+static int PNGCBAPI
+read_user_chunk_callback(png_struct *png_ptr, png_unknown_chunkp chunk)
+{
+   user_chunk_info *my_user_chunk_data =
+      (user_chunk_info*)png_get_user_chunk_ptr(png_ptr);
+
+   if (my_user_chunk_data == NULL)
+      png_error(png_ptr, "lost pointer to user chunk data");
+
+   /* Return one of the following:
+    *    return -n;  chunk had an error
+    *    return 0;   did not recognize
+    *    return n;   success
+    *
+    * The unknown chunk structure contains the chunk data:
+    * png_byte name[5];
+    * png_byte *data;
+    * size_t size;
+    *
+    * Note that libpng has already taken care of the CRC handling.
+    */
+
+   if (chunk->name[0] == 115 && chunk->name[1] ==  84 &&     /* s  T */
+       chunk->name[2] ==  69 && chunk->name[3] ==  82)       /* E  R */
+      {
+         /* Found sTER chunk */
+         if (chunk->size != 1)
+            return -1; /* Error return */
+
+         if (chunk->data[0] != 0 && chunk->data[0] != 1)
+            return -1;  /* Invalid mode */
+
+         if (set_chunk_location(png_ptr, my_user_chunk_data, have_sTER) != 0)
+         {
+            my_user_chunk_data->sTER_mode = chunk->data[0];
+            return 1;
+         }
+
+         else
+            return 0; /* duplicate sTER - give it to libpng */
+      }
+
+   if (chunk->name[0] != 118 || chunk->name[1] != 112 ||    /* v  p */
+       chunk->name[2] !=  65 || chunk->name[3] != 103)      /* A  g */
+      return 0; /* Did not recognize */
+
+   /* Found ImageMagick vpAg chunk */
+
+   if (chunk->size != 9)
+      return -1; /* Error return */
+
+   if (set_chunk_location(png_ptr, my_user_chunk_data, have_vpAg) == 0)
+      return 0;  /* duplicate vpAg */
+
+   my_user_chunk_data->vpAg_width = png_get_uint_31(png_ptr, chunk->data);
+   my_user_chunk_data->vpAg_height = png_get_uint_31(png_ptr, chunk->data + 4);
+   my_user_chunk_data->vpAg_units = chunk->data[8];
+
+   return 1;
+}
+
+#ifdef PNG_WRITE_SUPPORTED
+static void
+write_sTER_chunk(png_structp write_ptr, user_chunk_info *data)
+{
+   png_byte sTER[5] = {115,  84,  69,  82, '\0'};
+
+   if (verbose != 0)
+      fprintf(STDERR, "\n stereo mode = %d\n", data->sTER_mode);
+
+   png_write_chunk(write_ptr, sTER, &data->sTER_mode, 1);
+}
+
+static void
+write_vpAg_chunk(png_structp write_ptr, user_chunk_info *data)
+{
+   png_byte vpAg[5] = {118, 112,  65, 103, '\0'};
+
+   png_byte vpag_chunk_data[9];
+
+   if (verbose != 0)
+      fprintf(STDERR, " vpAg = %lu x %lu, units = %d\n",
+          (unsigned long)data->vpAg_width,
+          (unsigned long)data->vpAg_height,
+          data->vpAg_units);
+
+   png_save_uint_32(vpag_chunk_data, data->vpAg_width);
+   png_save_uint_32(vpag_chunk_data + 4, data->vpAg_height);
+   vpag_chunk_data[8] = data->vpAg_units;
+   png_write_chunk(write_ptr, vpAg, vpag_chunk_data, 9);
+}
+
+static void
+write_chunks(png_structp write_ptr, user_chunk_info *data, int location)
+{
+   int i;
+
+   /* Notice that this preserves the original chunk order, however chunks
+    * intercepted by the callback will be written *after* chunks passed to
+    * libpng.  This will actually reverse a pair of sTER chunks or a pair of
+    * vpAg chunks, resulting in an error later.  This is not worth worrying
+    * about - the chunks should not be duplicated!
+    */
+   for (i = 0; i < 2; ++i)
+   {
+      if (data->location[i] == (location | have_sTER))
+         write_sTER_chunk(write_ptr, data);
+
+      else if (data->location[i] == (location | have_vpAg))
+         write_vpAg_chunk(write_ptr, data);
+   }
+}
+#endif /* WRITE */
+#else /* !READ_USER_CHUNKS */
+#  define write_chunks(pp,loc) ((void)0)
+#endif
+/* END of code to demonstrate user chunk support */
+
+/* START of code to check that libpng has the required text support; this only
+ * checks for the write support because if read support is missing the chunk
+ * will simply not be reported back to pngtest.
+ */
+#ifdef PNG_TEXT_SUPPORTED
+static void
+pngtest_check_text_support(png_structp png_ptr, png_textp text_ptr,
+    int num_text)
+{
+   while (num_text > 0)
+   {
+      switch (text_ptr[--num_text].compression)
+      {
+         case PNG_TEXT_COMPRESSION_NONE:
+            break;
+
+         case PNG_TEXT_COMPRESSION_zTXt:
+#           ifndef PNG_WRITE_zTXt_SUPPORTED
+               ++unsupported_chunks;
+               /* In libpng 1.7 this now does an app-error, so stop it: */
+               text_ptr[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+#           endif
+            break;
+
+         case PNG_ITXT_COMPRESSION_NONE:
+         case PNG_ITXT_COMPRESSION_zTXt:
+#           ifndef PNG_WRITE_iTXt_SUPPORTED
+               ++unsupported_chunks;
+               text_ptr[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+#           endif
+            break;
+
+         default:
+            /* This is an error */
+            png_error(png_ptr, "invalid text chunk compression field");
+            break;
+      }
+   }
+}
+#endif
+/* END of code to check that libpng has the required text support */
+
+/* Test one file */
+static int
+test_one_file(const char *inname, const char *outname)
+{
+   static png_FILE_p fpin;
+   static png_FILE_p fpout;  /* "static" prevents setjmp corruption */
+   pngtest_error_parameters error_parameters;
+   png_structp read_ptr;
+   png_infop read_info_ptr, end_info_ptr;
+#ifdef PNG_WRITE_SUPPORTED
+   png_structp write_ptr;
+   png_infop write_info_ptr;
+   png_infop write_end_info_ptr;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   int interlace_preserved = 1;
+#endif /* WRITE_FILTER */
+#else /* !WRITE */
+   png_structp write_ptr = NULL;
+   png_infop write_info_ptr = NULL;
+   png_infop write_end_info_ptr = NULL;
+#endif /* !WRITE */
+   png_bytep row_buf;
+   png_uint_32 y;
+   png_uint_32 width, height;
+   int bit_depth, color_type;
+   user_chunk_info my_user_chunk_data;
+   int pass, num_passes;
+
+   row_buf = NULL;
+   error_parameters.file_name = inname;
+
+   if ((fpin = fopen(inname, "rb")) == NULL)
+   {
+      fprintf(STDERR, "Could not find input file %s\n", inname);
+      return 1;
+   }
+
+   if ((fpout = fopen(outname, "wb")) == NULL)
+   {
+      fprintf(STDERR, "Could not open output file %s\n", outname);
+      fclose(fpin);
+      return 1;
+   }
+
+   pngtest_debug("Allocating read and write structures");
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+   read_ptr =
+       png_create_read_struct_2(PNG_LIBPNG_VER_STRING, NULL,
+       NULL, NULL, NULL, png_debug_malloc, png_debug_free);
+#else
+   read_ptr =
+       png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+#endif
+   png_set_error_fn(read_ptr, &error_parameters, pngtest_error,
+       pngtest_warning);
+
+#ifdef PNG_WRITE_SUPPORTED
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+   write_ptr =
+       png_create_write_struct_2(PNG_LIBPNG_VER_STRING, NULL,
+       NULL, NULL, NULL, png_debug_malloc, png_debug_free);
+#else
+   write_ptr =
+       png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+#endif
+   png_set_error_fn(write_ptr, &error_parameters, pngtest_error,
+       pngtest_warning);
+#endif
+   pngtest_debug("Allocating read_info, write_info and end_info structures");
+   read_info_ptr = png_create_info_struct(read_ptr);
+   end_info_ptr = png_create_info_struct(read_ptr);
+#ifdef PNG_WRITE_SUPPORTED
+   write_info_ptr = png_create_info_struct(write_ptr);
+   write_end_info_ptr = png_create_info_struct(write_ptr);
+#endif
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   init_user_chunk_info(read_info_ptr, &my_user_chunk_data);
+   png_set_read_user_chunk_fn(read_ptr, &my_user_chunk_data,
+       read_user_chunk_callback);
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+   pngtest_debug("Setting jmpbuf for read struct");
+   if (setjmp(png_jmpbuf(read_ptr)))
+   {
+      fprintf(STDERR, "%s -> %s: libpng read error\n", inname, outname);
+      png_free(read_ptr, row_buf);
+      row_buf = NULL;
+      if (verbose != 0)
+        fprintf(STDERR, "   destroy read structs\n");
+      png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
+#ifdef PNG_WRITE_SUPPORTED
+      if (verbose != 0)
+        fprintf(STDERR, "   destroy write structs\n");
+      png_destroy_info_struct(write_ptr, &write_end_info_ptr);
+      png_destroy_write_struct(&write_ptr, &write_info_ptr);
+#endif
+      fclose(fpin);
+      fclose(fpout);
+      return 1;
+   }
+
+#ifdef PNG_WRITE_SUPPORTED
+   pngtest_debug("Setting jmpbuf for write struct");
+
+   if (setjmp(png_jmpbuf(write_ptr)))
+   {
+      fprintf(STDERR, "%s -> %s: libpng write error\n", inname, outname);
+      png_free(read_ptr, row_buf);
+      row_buf = NULL;
+      if (verbose != 0)
+        fprintf(STDERR, "   destroying read structs\n");
+      png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
+      if (verbose != 0)
+        fprintf(STDERR, "   destroying write structs\n");
+      png_destroy_info_struct(write_ptr, &write_end_info_ptr);
+      png_destroy_write_struct(&write_ptr, &write_info_ptr);
+      fclose(fpin);
+      fclose(fpout);
+      return 1;
+   }
+#endif
+#endif
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+   if (strict != 0)
+   {
+      /* Treat png_benign_error() as errors on read */
+      png_set_benign_errors(read_ptr, 0);
+
+# ifdef PNG_WRITE_SUPPORTED
+      /* Treat them as errors on write */
+      png_set_benign_errors(write_ptr, 0);
+# endif
+
+      /* if strict is not set, then app warnings and errors are treated as
+       * warnings in release builds, but not in unstable builds; this can be
+       * changed with '--relaxed'.
+       */
+   }
+
+   else if (relaxed != 0)
+   {
+      /* Allow application (pngtest) errors and warnings to pass */
+      png_set_benign_errors(read_ptr, 1);
+
+      /* Turn off CRC checking while reading */
+      png_set_crc_action(read_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
+
+#ifdef PNG_IGNORE_ADLER32
+      /* Turn off ADLER32 checking while reading */
+      png_set_option(read_ptr, PNG_IGNORE_ADLER32, PNG_OPTION_ON);
+#endif
+
+# ifdef PNG_WRITE_SUPPORTED
+      png_set_benign_errors(write_ptr, 1);
+# endif
+
+   }
+#endif /* BENIGN_ERRORS */
+
+   pngtest_debug("Initializing input and output streams");
+#ifdef PNG_STDIO_SUPPORTED
+   png_init_io(read_ptr, fpin);
+#  ifdef PNG_WRITE_SUPPORTED
+   png_init_io(write_ptr, fpout);
+#  endif
+#else
+   png_set_read_fn(read_ptr, (png_voidp)fpin, pngtest_read_data);
+#  ifdef PNG_WRITE_SUPPORTED
+   png_set_write_fn(write_ptr, (png_voidp)fpout,  pngtest_write_data,
+#    ifdef PNG_WRITE_FLUSH_SUPPORTED
+       pngtest_flush);
+#    else
+       NULL);
+#    endif
+#  endif
+#endif
+
+   if (status_dots_requested == 1)
+   {
+#ifdef PNG_WRITE_SUPPORTED
+      png_set_write_status_fn(write_ptr, write_row_callback);
+#endif
+      png_set_read_status_fn(read_ptr, read_row_callback);
+   }
+
+   else
+   {
+#ifdef PNG_WRITE_SUPPORTED
+      png_set_write_status_fn(write_ptr, NULL);
+#endif
+      png_set_read_status_fn(read_ptr, NULL);
+   }
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   png_set_read_user_transform_fn(read_ptr, read_user_callback);
+#endif
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+   zero_samples = 0;
+   png_set_write_user_transform_fn(write_ptr, count_zero_samples);
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   /* Preserve all the unknown chunks, if possible.  If this is disabled, then
+    * even if the png_{get,set}_unknown_chunks stuff is enabled, we can't use
+    * libpng to *save* the unknown chunks on read (because we can't switch the
+    * save option on!)
+    *
+    * Notice that if SET_UNKNOWN_CHUNKS is *not* supported, the reader will
+    * discard all unknown chunks, and the writer will write them all.
+    */
+#ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+   png_set_keep_unknown_chunks(read_ptr, PNG_HANDLE_CHUNK_ALWAYS,
+       NULL, 0);
+#endif
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+   png_set_keep_unknown_chunks(write_ptr, PNG_HANDLE_CHUNK_ALWAYS,
+       NULL, 0);
+#endif
+#endif
+
+   pngtest_debug("Reading info struct");
+   png_read_info(read_ptr, read_info_ptr);
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+   /* This is a bit of a hack; there is no obvious way in the callback function
+    * to determine that the chunks before the first IDAT have been read, so
+    * remove the info_ptr (which is only used to determine position relative to
+    * PLTE) here to indicate that we are after the IDAT.
+    */
+   my_user_chunk_data.info_ptr = NULL;
+#endif
+
+   pngtest_debug("Transferring info struct");
+   {
+      int interlace_type, compression_type, filter_type;
+
+      if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth,
+          &color_type, &interlace_type, &compression_type, &filter_type) != 0)
+      {
+         png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,
+             color_type, interlace_type, compression_type, filter_type);
+         /* num_passes may not be available below if interlace support is not
+          * provided by libpng for both read and write.
+          */
+         switch (interlace_type)
+         {
+            case PNG_INTERLACE_NONE:
+               num_passes = 1;
+               break;
+
+            case PNG_INTERLACE_ADAM7:
+               num_passes = 7;
+               break;
+
+            default:
+               png_error(read_ptr, "invalid interlace type");
+               /*NOT REACHED*/
+         }
+      }
+
+      else
+         png_error(read_ptr, "png_get_IHDR failed");
+   }
+#ifdef PNG_FIXED_POINT_SUPPORTED
+#ifdef PNG_cHRM_SUPPORTED
+   {
+      png_fixed_point white_x, white_y, red_x, red_y, green_x, green_y, blue_x,
+          blue_y;
+
+      if (png_get_cHRM_fixed(read_ptr, read_info_ptr, &white_x, &white_y,
+          &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
+      {
+         png_set_cHRM_fixed(write_ptr, write_info_ptr, white_x, white_y, red_x,
+             red_y, green_x, green_y, blue_x, blue_y);
+      }
+   }
+#endif
+#ifdef PNG_gAMA_SUPPORTED
+   {
+      png_fixed_point gamma;
+
+      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma) != 0)
+         png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma);
+   }
+#endif
+#else /* Use floating point versions */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+#ifdef PNG_cHRM_SUPPORTED
+   {
+      double white_x, white_y, red_x, red_y, green_x, green_y, blue_x,
+          blue_y;
+
+      if (png_get_cHRM(read_ptr, read_info_ptr, &white_x, &white_y, &red_x,
+          &red_y, &green_x, &green_y, &blue_x, &blue_y) != 0)
+      {
+         png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x,
+             red_y, green_x, green_y, blue_x, blue_y);
+      }
+   }
+#endif
+#ifdef PNG_gAMA_SUPPORTED
+   {
+      double gamma;
+
+      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma) != 0)
+         png_set_gAMA(write_ptr, write_info_ptr, gamma);
+   }
+#endif
+#endif /* Floating point */
+#endif /* Fixed point */
+#ifdef PNG_iCCP_SUPPORTED
+   {
+      png_charp name;
+      png_bytep profile;
+      png_uint_32 proflen;
+      int compression_type;
+
+      if (png_get_iCCP(read_ptr, read_info_ptr, &name, &compression_type,
+          &profile, &proflen) != 0)
+      {
+         png_set_iCCP(write_ptr, write_info_ptr, name, compression_type,
+             profile, proflen);
+      }
+   }
+#endif
+#ifdef PNG_sRGB_SUPPORTED
+   {
+      int intent;
+
+      if (png_get_sRGB(read_ptr, read_info_ptr, &intent) != 0)
+         png_set_sRGB(write_ptr, write_info_ptr, intent);
+   }
+#endif
+   {
+      png_colorp palette;
+      int num_palette;
+
+      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette) != 0)
+         png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette);
+   }
+#ifdef PNG_bKGD_SUPPORTED
+   {
+      png_color_16p background;
+
+      if (png_get_bKGD(read_ptr, read_info_ptr, &background) != 0)
+         png_set_bKGD(write_ptr, write_info_ptr, background);
+   }
+#endif
+#ifdef PNG_READ_eXIf_SUPPORTED
+   {
+      png_bytep exif = NULL;
+      png_uint_32 exif_length;
+
+      if (png_get_eXIf_1(read_ptr, read_info_ptr, &exif_length, &exif) != 0)
+      {
+         if (exif_length > 1)
+            fprintf(STDERR," eXIf type %c%c, %lu bytes\n",exif[0],exif[1],
+               (unsigned long)exif_length);
+# ifdef PNG_WRITE_eXIf_SUPPORTED
+         png_set_eXIf_1(write_ptr, write_info_ptr, exif_length, exif);
+# endif
+      }
+   }
+#endif
+#ifdef PNG_hIST_SUPPORTED
+   {
+      png_uint_16p hist;
+
+      if (png_get_hIST(read_ptr, read_info_ptr, &hist) != 0)
+         png_set_hIST(write_ptr, write_info_ptr, hist);
+   }
+#endif
+#ifdef PNG_oFFs_SUPPORTED
+   {
+      png_int_32 offset_x, offset_y;
+      int unit_type;
+
+      if (png_get_oFFs(read_ptr, read_info_ptr, &offset_x, &offset_y,
+          &unit_type) != 0)
+         png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);
+   }
+#endif
+#ifdef PNG_pCAL_SUPPORTED
+   {
+      png_charp purpose, units;
+      png_charpp params;
+      png_int_32 X0, X1;
+      int type, nparams;
+
+      if (png_get_pCAL(read_ptr, read_info_ptr, &purpose, &X0, &X1, &type,
+          &nparams, &units, &params) != 0)
+         png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type,
+             nparams, units, params);
+   }
+#endif
+#ifdef PNG_pHYs_SUPPORTED
+   {
+      png_uint_32 res_x, res_y;
+      int unit_type;
+
+      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y,
+          &unit_type) != 0)
+         png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);
+   }
+#endif
+#ifdef PNG_sBIT_SUPPORTED
+   {
+      png_color_8p sig_bit;
+
+      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit) != 0)
+         png_set_sBIT(write_ptr, write_info_ptr, sig_bit);
+   }
+#endif
+#ifdef PNG_sCAL_SUPPORTED
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
+   defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+   {
+      int unit;
+      double scal_width, scal_height;
+
+      if (png_get_sCAL(read_ptr, read_info_ptr, &unit, &scal_width,
+          &scal_height) != 0)
+         png_set_sCAL(write_ptr, write_info_ptr, unit, scal_width, scal_height);
+   }
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   {
+      int unit;
+      png_charp scal_width, scal_height;
+
+      if (png_get_sCAL_s(read_ptr, read_info_ptr, &unit, &scal_width,
+           &scal_height) != 0)
+      {
+         png_set_sCAL_s(write_ptr, write_info_ptr, unit, scal_width,
+             scal_height);
+      }
+   }
+#endif
+#endif
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+   {
+       png_sPLT_tp entries;
+
+       int num_entries = png_get_sPLT(read_ptr, read_info_ptr, &entries);
+       if (num_entries != 0)
+           png_set_sPLT(write_ptr, write_info_ptr, entries, num_entries);
+   }
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+   {
+      png_textp text_ptr;
+      int num_text;
+
+      if (png_get_text(read_ptr, read_info_ptr, &text_ptr, &num_text) > 0)
+      {
+         pngtest_debug1("Handling %d iTXt/tEXt/zTXt chunks", num_text);
+
+         pngtest_check_text_support(read_ptr, text_ptr, num_text);
+
+         if (verbose != 0)
+         {
+            int i;
+
+            fprintf(STDERR,"\n");
+            for (i = 0; i < num_text; i++)
+            {
+               fprintf(STDERR,"   Text compression[%d]=%d\n",
+                   i, text_ptr[i].compression);
+            }
+         }
+
+         png_set_text(write_ptr, write_info_ptr, text_ptr, num_text);
+      }
+   }
+#endif
+#ifdef PNG_tIME_SUPPORTED
+   {
+      png_timep mod_time;
+
+      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time) != 0)
+      {
+         png_set_tIME(write_ptr, write_info_ptr, mod_time);
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
+            tIME_string[(sizeof tIME_string) - 1] = '\0';
+
+         else
+         {
+            strncpy(tIME_string, "*** invalid time ***", (sizeof tIME_string));
+            tIME_string[(sizeof tIME_string) - 1] = '\0';
+         }
+
+         tIME_chunk_present++;
+#endif /* TIME_RFC1123 */
+      }
+   }
+#endif
+#ifdef PNG_tRNS_SUPPORTED
+   {
+      png_bytep trans_alpha;
+      int num_trans;
+      png_color_16p trans_color;
+
+      if (png_get_tRNS(read_ptr, read_info_ptr, &trans_alpha, &num_trans,
+          &trans_color) != 0)
+      {
+         int sample_max = (1 << bit_depth);
+         /* libpng doesn't reject a tRNS chunk with out-of-range samples */
+         if (!((color_type == PNG_COLOR_TYPE_GRAY &&
+             (int)trans_color->gray > sample_max) ||
+             (color_type == PNG_COLOR_TYPE_RGB &&
+             ((int)trans_color->red > sample_max ||
+             (int)trans_color->green > sample_max ||
+             (int)trans_color->blue > sample_max))))
+            png_set_tRNS(write_ptr, write_info_ptr, trans_alpha, num_trans,
+               trans_color);
+      }
+   }
+#endif
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+   {
+      png_unknown_chunkp unknowns;
+      int num_unknowns = png_get_unknown_chunks(read_ptr, read_info_ptr,
+          &unknowns);
+
+      if (num_unknowns != 0)
+         png_set_unknown_chunks(write_ptr, write_info_ptr, unknowns,
+             num_unknowns);
+   }
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+   pngtest_debug("Writing info struct");
+
+   /* Write the info in two steps so that if we write the 'unknown' chunks here
+    * they go to the correct place.
+    */
+   png_write_info_before_PLTE(write_ptr, write_info_ptr);
+
+   write_chunks(write_ptr, &my_user_chunk_data, before_PLTE); /* before PLTE */
+
+   png_write_info(write_ptr, write_info_ptr);
+
+   write_chunks(write_ptr, &my_user_chunk_data, before_IDAT); /* after PLTE */
+
+   png_write_info(write_ptr, write_end_info_ptr);
+
+   write_chunks(write_ptr, &my_user_chunk_data, after_IDAT); /* after IDAT */
+
+#ifdef PNG_COMPRESSION_COMPAT
+   /* Test the 'compatibility' setting here, if it is available. */
+   png_set_compression(write_ptr, PNG_COMPRESSION_COMPAT);
+#endif
+#endif
+
+   pngtest_debug("Writing row data");
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) &&\
+   defined(PNG_WRITE_INTERLACING_SUPPORTED)
+   /* Both must be defined for libpng to be able to handle the interlace,
+    * otherwise it gets handled below by simply reading and writing the passes
+    * directly.
+    */
+   if (png_set_interlace_handling(read_ptr) != num_passes)
+      png_error(write_ptr,
+          "png_set_interlace_handling(read): wrong pass count ");
+   if (png_set_interlace_handling(write_ptr) != num_passes)
+      png_error(write_ptr,
+          "png_set_interlace_handling(write): wrong pass count ");
+#else /* png_set_interlace_handling not called on either read or write */
+#  define calc_pass_height
+#endif /* not using libpng interlace handling */
+
+#ifdef PNGTEST_TIMING
+   t_stop = (float)clock();
+   t_misc += (t_stop - t_start);
+   t_start = t_stop;
+#endif
+   for (pass = 0; pass < num_passes; pass++)
+   {
+#     ifdef calc_pass_height
+         png_uint_32 pass_height;
+
+         if (num_passes == 7) /* interlaced */
+         {
+            if (PNG_PASS_COLS(width, pass) > 0)
+               pass_height = PNG_PASS_ROWS(height, pass);
+
+            else
+               pass_height = 0;
+         }
+
+         else /* not interlaced */
+            pass_height = height;
+#     else
+#        define pass_height height
+#     endif
+
+      pngtest_debug1("Writing row data for pass %d", pass);
+      for (y = 0; y < pass_height; y++)
+      {
+         pngtest_debug2("Allocating row buffer (pass %d, y = %u)...", pass, y);
+
+         row_buf = (png_bytep)png_malloc(read_ptr,
+             png_get_rowbytes(read_ptr, read_info_ptr));
+
+         pngtest_debug2("\t%p (%lu bytes)", row_buf,
+             (unsigned long)png_get_rowbytes(read_ptr, read_info_ptr));
+
+         png_read_rows(read_ptr, (png_bytepp)&row_buf, NULL, 1);
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNGTEST_TIMING
+         t_stop = (float)clock();
+         t_decode += (t_stop - t_start);
+         t_start = t_stop;
+#endif
+         png_write_rows(write_ptr, (png_bytepp)&row_buf, 1);
+#ifdef PNGTEST_TIMING
+         t_stop = (float)clock();
+         t_encode += (t_stop - t_start);
+         t_start = t_stop;
+#endif
+#endif /* WRITE */
+
+         pngtest_debug2("Freeing row buffer (pass %d, y = %u)", pass, y);
+         png_free(read_ptr, row_buf);
+         row_buf = NULL;
+      }
+   }
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#  ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+      png_free_data(read_ptr, read_info_ptr, PNG_FREE_UNKN, -1);
+#  endif
+#  ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+      png_free_data(write_ptr, write_info_ptr, PNG_FREE_UNKN, -1);
+#  endif
+#endif
+
+   pngtest_debug("Reading and writing end_info data");
+
+   png_read_end(read_ptr, end_info_ptr);
+#ifdef PNG_TEXT_SUPPORTED
+   {
+      png_textp text_ptr;
+      int num_text;
+
+      if (png_get_text(read_ptr, end_info_ptr, &text_ptr, &num_text) > 0)
+      {
+         pngtest_debug1("Handling %d iTXt/tEXt/zTXt chunks", num_text);
+
+         pngtest_check_text_support(read_ptr, text_ptr, num_text);
+
+         if (verbose != 0)
+         {
+            int i;
+
+            fprintf(STDERR,"\n");
+            for (i = 0; i < num_text; i++)
+            {
+               fprintf(STDERR,"   Text compression[%d]=%d\n",
+                   i, text_ptr[i].compression);
+            }
+         }
+
+         png_set_text(write_ptr, write_end_info_ptr, text_ptr, num_text);
+      }
+   }
+#endif
+#ifdef PNG_READ_eXIf_SUPPORTED
+   {
+      png_bytep exif = NULL;
+      png_uint_32 exif_length;
+
+      if (png_get_eXIf_1(read_ptr, end_info_ptr, &exif_length, &exif) != 0)
+      {
+         if (exif_length > 1)
+            fprintf(STDERR," eXIf type %c%c, %lu bytes\n",exif[0],exif[1],
+               (unsigned long)exif_length);
+# ifdef PNG_WRITE_eXIf_SUPPORTED
+         png_set_eXIf_1(write_ptr, write_end_info_ptr, exif_length, exif);
+# endif
+      }
+   }
+#endif
+#ifdef PNG_tIME_SUPPORTED
+   {
+      png_timep mod_time;
+
+      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time) != 0)
+      {
+         png_set_tIME(write_ptr, write_end_info_ptr, mod_time);
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+         if (png_convert_to_rfc1123_buffer(tIME_string, mod_time) != 0)
+            tIME_string[(sizeof tIME_string) - 1] = '\0';
+
+         else
+         {
+            strncpy(tIME_string, "*** invalid time ***", sizeof tIME_string);
+            tIME_string[(sizeof tIME_string)-1] = '\0';
+         }
+
+         tIME_chunk_present++;
+#endif /* TIME_RFC1123 */
+      }
+   }
+#endif
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+   {
+      png_unknown_chunkp unknowns;
+      int num_unknowns = png_get_unknown_chunks(read_ptr, end_info_ptr,
+          &unknowns);
+
+      if (num_unknowns != 0)
+         png_set_unknown_chunks(write_ptr, write_end_info_ptr, unknowns,
+             num_unknowns);
+   }
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+   /* Normally one would use Z_DEFAULT_STRATEGY for text compression.
+    * This is here just to make pngtest replicate the results from libpng
+    * versions prior to 1.5.4, and to test this new API.
+    */
+   png_set_text_compression_strategy(write_ptr, Z_FILTERED);
+#endif
+
+   /* When the unknown vpAg/sTER chunks are written by pngtest the only way to
+    * do it is to write them *before* calling png_write_end.  When unknown
+    * chunks are written by libpng, however, they are written just before IEND.
+    * There seems to be no way round this, however vpAg/sTER are not expected
+    * after IDAT.
+    */
+   write_chunks(write_ptr, &my_user_chunk_data, after_IDAT);
+
+   png_write_end(write_ptr, write_end_info_ptr);
+#endif
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+   if (verbose != 0)
+   {
+      png_uint_32 iwidth, iheight;
+      iwidth = png_get_image_width(write_ptr, write_info_ptr);
+      iheight = png_get_image_height(write_ptr, write_info_ptr);
+      fprintf(STDERR, "\n Image width = %lu, height = %lu\n",
+          (unsigned long)iwidth, (unsigned long)iheight);
+   }
+#endif
+
+   pngtest_debug("Destroying data structs");
+   pngtest_debug("Destroying read_ptr, read_info_ptr, end_info_ptr");
+   png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
+#ifdef PNG_WRITE_SUPPORTED
+   pngtest_debug("Destroying write_end_info_ptr");
+   png_destroy_info_struct(write_ptr, &write_end_info_ptr);
+   pngtest_debug("Destroying write_ptr, write_info_ptr");
+   png_destroy_write_struct(&write_ptr, &write_info_ptr);
+#endif
+   pngtest_debug("Destruction complete.");
+
+   fclose(fpin);
+   fclose(fpout);
+
+   /* Summarize any warnings or errors and in 'strict' mode fail the test.
+    * Unsupported chunks can result in warnings, in that case ignore the strict
+    * setting, otherwise fail the test on warnings as well as errors.
+    */
+   if (error_count > 0)
+   {
+      /* We don't really expect to get here because of the setjmp handling
+       * above, but this is safe.
+       */
+      fprintf(STDERR, "\n  %s: %d libpng errors found (%d warnings)",
+          inname, error_count, warning_count);
+
+      if (strict != 0)
+         return 1;
+   }
+
+#  ifdef PNG_WRITE_SUPPORTED
+      /* If there is no write support nothing was written! */
+      else if (unsupported_chunks > 0)
+      {
+         fprintf(STDERR, "\n  %s: unsupported chunks (%d)%s",
+             inname, unsupported_chunks, strict ? ": IGNORED --strict!" : "");
+      }
+#  endif
+
+   else if (warning_count > 0)
+   {
+      fprintf(STDERR, "\n  %s: %d libpng warnings found",
+          inname, warning_count);
+
+      if (strict != 0)
+         return 1;
+   }
+
+   pngtest_debug("Opening files for comparison");
+   if ((fpin = fopen(inname, "rb")) == NULL)
+   {
+      fprintf(STDERR, "Could not find file %s\n", inname);
+      return 1;
+   }
+
+   if ((fpout = fopen(outname, "rb")) == NULL)
+   {
+      fprintf(STDERR, "Could not find file %s\n", outname);
+      fclose(fpin);
+      return 1;
+   }
+
+#if defined (PNG_WRITE_SUPPORTED) /* else nothing was written */ &&\
+    defined (PNG_WRITE_FILTER_SUPPORTED)
+   if (interlace_preserved != 0) /* else the files will be changed */
+   {
+      for (;;)
+      {
+         static int wrote_question = 0;
+         size_t num_in, num_out;
+         char inbuf[256], outbuf[256];
+
+         num_in = fread(inbuf, 1, sizeof inbuf, fpin);
+         num_out = fread(outbuf, 1, sizeof outbuf, fpout);
+
+         if (num_in != num_out)
+         {
+            fprintf(STDERR, "\nFiles %s and %s are of a different size\n",
+                inname, outname);
+
+            if (wrote_question == 0 && unsupported_chunks == 0)
+            {
+               fprintf(STDERR,
+                   "   Was %s written with the same maximum IDAT"
+                   " chunk size (%d bytes),",
+                   inname, PNG_ZBUF_SIZE);
+               fprintf(STDERR,
+                   "\n   filtering heuristic (libpng default), compression");
+               fprintf(STDERR,
+                   " level (zlib default),\n   and zlib version (%s)?\n\n",
+                   ZLIB_VERSION);
+               wrote_question = 1;
+            }
+
+            fclose(fpin);
+            fclose(fpout);
+
+            if (strict != 0 && unsupported_chunks == 0)
+              return 1;
+
+            else
+              return 0;
+         }
+
+         if (num_in == 0)
+            break;
+
+         if (memcmp(inbuf, outbuf, num_in))
+         {
+            fprintf(STDERR, "\nFiles %s and %s are different\n", inname,
+                outname);
+
+            if (wrote_question == 0 && unsupported_chunks == 0)
+            {
+               fprintf(STDERR,
+                   "   Was %s written with the same maximum"
+                   " IDAT chunk size (%d bytes),",
+                    inname, PNG_ZBUF_SIZE);
+               fprintf(STDERR,
+                   "\n   filtering heuristic (libpng default), compression");
+               fprintf(STDERR,
+                   " level (zlib default),\n   and zlib version (%s)?\n\n",
+                 ZLIB_VERSION);
+               wrote_question = 1;
+            }
+
+            fclose(fpin);
+            fclose(fpout);
+
+            /* NOTE: the unsupported_chunks escape is permitted here because
+             * unsupported text chunk compression will result in the compression
+             * mode being changed (to NONE) yet, in the test case, the result
+             * can be exactly the same size!
+             */
+            if (strict != 0 && unsupported_chunks == 0)
+              return 1;
+
+            else
+              return 0;
+         }
+      }
+   }
+#endif /* WRITE && WRITE_FILTER */
+
+   fclose(fpin);
+   fclose(fpout);
+
+   return 0;
+}
+
+/* Input and output filenames */
+#ifdef RISCOS
+static const char *inname = "pngtest/png";
+static const char *outname = "pngout/png";
+#else
+static const char *inname = "pngtest.png";
+static const char *outname = "pngout.png";
+#endif
+
+int
+main(int argc, char *argv[])
+{
+   int multiple = 0;
+   int ierror = 0;
+
+   png_structp dummy_ptr;
+
+   fprintf(STDERR, "\n Testing libpng version %s\n", PNG_LIBPNG_VER_STRING);
+   fprintf(STDERR, "   with zlib   version %s\n", ZLIB_VERSION);
+   fprintf(STDERR, "%s", png_get_copyright(NULL));
+   /* Show the version of libpng used in building the library */
+   fprintf(STDERR, " library (%lu):%s",
+       (unsigned long)png_access_version_number(),
+       png_get_header_version(NULL));
+
+   /* Show the version of libpng used in building the application */
+   fprintf(STDERR, " pngtest (%lu):%s", (unsigned long)PNG_LIBPNG_VER,
+       PNG_HEADER_VERSION_STRING);
+
+   /* Do some consistency checking on the memory allocation settings, I'm
+    * not sure this matters, but it is nice to know, the first of these
+    * tests should be impossible because of the way the macros are set
+    * in pngconf.h
+    */
+#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
+      fprintf(STDERR, " NOTE: Zlib compiled for max 64k, libpng not\n");
+#endif
+   /* I think the following can happen. */
+#if !defined(MAXSEG_64K) && defined(PNG_MAX_MALLOC_64K)
+      fprintf(STDERR, " NOTE: libpng compiled for max 64k, zlib not\n");
+#endif
+
+   if (strcmp(png_libpng_ver, PNG_LIBPNG_VER_STRING) != 0)
+   {
+      fprintf(STDERR, "Warning: mismatching versions of png.h and png.c\n");
+      fprintf(STDERR, "  png.h version string: %s\n", PNG_LIBPNG_VER_STRING);
+      fprintf(STDERR, "  png.c version string: %s\n\n", png_libpng_ver);
+      ++ierror;
+   }
+
+   if (argc > 1)
+   {
+      if (strcmp(argv[1], "-m") == 0)
+      {
+         multiple = 1;
+         status_dots_requested = 0;
+      }
+
+      else if (strcmp(argv[1], "-mv") == 0 ||
+               strcmp(argv[1], "-vm") == 0 )
+      {
+         multiple = 1;
+         verbose = 1;
+         status_dots_requested = 1;
+      }
+
+      else if (strcmp(argv[1], "-v") == 0)
+      {
+         verbose = 1;
+         status_dots_requested = 1;
+         inname = argv[2];
+      }
+
+      else if (strcmp(argv[1], "--strict") == 0)
+      {
+         status_dots_requested = 0;
+         verbose = 1;
+         inname = argv[2];
+         strict++;
+         relaxed = 0;
+         multiple = 1;
+      }
+
+      else if (strcmp(argv[1], "--relaxed") == 0)
+      {
+         status_dots_requested = 0;
+         verbose = 1;
+         inname = argv[2];
+         strict = 0;
+         relaxed++;
+         multiple = 1;
+      }
+      else if (strcmp(argv[1], "--xfail") == 0)
+      {
+         status_dots_requested = 0;
+         verbose = 1;
+         inname = argv[2];
+         strict = 0;
+         xfail++;
+         relaxed++;
+         multiple = 1;
+      }
+
+      else
+      {
+         inname = argv[1];
+         status_dots_requested = 0;
+      }
+   }
+
+   if (multiple == 0 && argc == 3 + verbose)
+      outname = argv[2 + verbose];
+
+   if ((multiple == 0 && argc > 3 + verbose) ||
+       (multiple != 0 && argc < 2))
+   {
+      fprintf(STDERR,
+          "usage: %s [infile.png] [outfile.png]\n\t%s -m {infile.png}\n",
+          argv[0], argv[0]);
+      fprintf(STDERR,
+          "  reads/writes one PNG file (without -m) or multiple files (-m)\n");
+      fprintf(STDERR,
+          "  with -m %s is used as a temporary file\n", outname);
+      exit(1);
+   }
+
+   if (multiple != 0)
+   {
+      int i;
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+      int allocation_now = current_allocation;
+#endif
+      for (i = 2; i < argc; ++i)
+      {
+         int kerror;
+         fprintf(STDERR, "\n Testing %s:", argv[i]);
+#if PNG_DEBUG > 0
+         fprintf(STDERR, "\n");
+#endif
+         kerror = test_one_file(argv[i], outname);
+         if (kerror == 0)
+         {
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+            fprintf(STDERR, "\n PASS (%lu zero samples)\n",
+                (unsigned long)zero_samples);
+#else
+            fprintf(STDERR, " PASS\n");
+#endif
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+            if (tIME_chunk_present != 0)
+               fprintf(STDERR, " tIME = %s\n", tIME_string);
+
+            tIME_chunk_present = 0;
+#endif /* TIME_RFC1123 */
+         }
+
+         else
+         {
+            if (xfail)
+              fprintf(STDERR, " XFAIL\n");
+            else
+            {
+              fprintf(STDERR, " FAIL\n");
+              ierror += kerror;
+            }
+         }
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+         if (allocation_now != current_allocation)
+            fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n",
+                current_allocation - allocation_now);
+
+         if (current_allocation != 0)
+         {
+            memory_infop pinfo = pinformation;
+
+            fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n",
+                current_allocation);
+
+            while (pinfo != NULL)
+            {
+               fprintf(STDERR, " %lu bytes at %p\n",
+                   (unsigned long)pinfo->size,
+                   pinfo->pointer);
+               pinfo = pinfo->next;
+            }
+         }
+#endif
+      }
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+         fprintf(STDERR, " Current memory allocation: %10d bytes\n",
+             current_allocation);
+         fprintf(STDERR, " Maximum memory allocation: %10d bytes\n",
+             maximum_allocation);
+         fprintf(STDERR, " Total   memory allocation: %10d bytes\n",
+             total_allocation);
+         fprintf(STDERR, "     Number of allocations: %10d\n",
+             num_allocations);
+#endif
+   }
+
+   else
+   {
+      int i;
+      for (i = 0; i < 3; ++i)
+      {
+         int kerror;
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+         int allocation_now = current_allocation;
+#endif
+         if (i == 1)
+            status_dots_requested = 1;
+
+         else if (verbose == 0)
+            status_dots_requested = 0;
+
+         if (i == 0 || verbose == 1 || ierror != 0)
+         {
+            fprintf(STDERR, "\n Testing %s:", inname);
+#if PNG_DEBUG > 0
+            fprintf(STDERR, "\n");
+#endif
+         }
+
+         kerror = test_one_file(inname, outname);
+
+         if (kerror == 0)
+         {
+            if (verbose == 1 || i == 2)
+            {
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+                fprintf(STDERR, "\n PASS (%lu zero samples)\n",
+                    (unsigned long)zero_samples);
+#else
+                fprintf(STDERR, " PASS\n");
+#endif
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+             if (tIME_chunk_present != 0)
+                fprintf(STDERR, " tIME = %s\n", tIME_string);
+#endif /* TIME_RFC1123 */
+            }
+         }
+
+         else
+         {
+            if (verbose == 0 && i != 2)
+            {
+               fprintf(STDERR, "\n Testing %s:", inname);
+#if PNG_DEBUG > 0
+               fprintf(STDERR, "\n");
+#endif
+            }
+
+            if (xfail)
+              fprintf(STDERR, " XFAIL\n");
+            else
+            {
+              fprintf(STDERR, " FAIL\n");
+              ierror += kerror;
+            }
+         }
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+         if (allocation_now != current_allocation)
+             fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n",
+                 current_allocation - allocation_now);
+
+         if (current_allocation != 0)
+         {
+             memory_infop pinfo = pinformation;
+
+             fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n",
+                 current_allocation);
+
+             while (pinfo != NULL)
+             {
+                fprintf(STDERR, " %lu bytes at %p\n",
+                    (unsigned long)pinfo->size, pinfo->pointer);
+                pinfo = pinfo->next;
+             }
+          }
+#endif
+       }
+#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
+       fprintf(STDERR, " Current memory allocation: %10d bytes\n",
+           current_allocation);
+       fprintf(STDERR, " Maximum memory allocation: %10d bytes\n",
+           maximum_allocation);
+       fprintf(STDERR, " Total   memory allocation: %10d bytes\n",
+           total_allocation);
+       fprintf(STDERR, "     Number of allocations: %10d\n",
+           num_allocations);
+#endif
+   }
+
+#ifdef PNGTEST_TIMING
+   t_stop = (float)clock();
+   t_misc += (t_stop - t_start);
+   t_start = t_stop;
+   fprintf(STDERR, " CPU time used = %.3f seconds",
+       (t_misc+t_decode+t_encode)/(float)CLOCKS_PER_SEC);
+   fprintf(STDERR, " (decoding %.3f,\n",
+       t_decode/(float)CLOCKS_PER_SEC);
+   fprintf(STDERR, "        encoding %.3f ,",
+       t_encode/(float)CLOCKS_PER_SEC);
+   fprintf(STDERR, " other %.3f seconds)\n\n",
+       t_misc/(float)CLOCKS_PER_SEC);
+#endif
+
+   if (ierror == 0)
+      fprintf(STDERR, " libpng passes test\n");
+
+   else
+      fprintf(STDERR, " libpng FAILS test\n");
+
+   dummy_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+   fprintf(STDERR, " Default limits:\n");
+   fprintf(STDERR, "  width_max  = %lu\n",
+       (unsigned long) png_get_user_width_max(dummy_ptr));
+   fprintf(STDERR, "  height_max = %lu\n",
+       (unsigned long) png_get_user_height_max(dummy_ptr));
+   if (png_get_chunk_cache_max(dummy_ptr) == 0)
+      fprintf(STDERR, "  cache_max  = unlimited\n");
+   else
+      fprintf(STDERR, "  cache_max  = %lu\n",
+          (unsigned long) png_get_chunk_cache_max(dummy_ptr));
+   if (png_get_chunk_malloc_max(dummy_ptr) == 0)
+      fprintf(STDERR, "  malloc_max = unlimited\n");
+   else
+      fprintf(STDERR, "  malloc_max = %lu\n",
+          (unsigned long) png_get_chunk_malloc_max(dummy_ptr));
+   png_destroy_read_struct(&dummy_ptr, NULL, NULL);
+
+   return (ierror != 0);
+}
+#else
+int
+main(void)
+{
+   fprintf(STDERR,
+       " test ignored because libpng was not built with read support\n");
+   /* And skip this test */
+   return SKIP;
+}
+#endif
Index: /trunk/src/libs/libpng-1.6.45/pngtrans.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngtrans.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngtrans.c	(revision 107811)
@@ -0,0 +1,868 @@
+
+/* pngtrans.c - transforms the data in a row (used by both readers and writers)
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Turn on BGR-to-RGB mapping */
+void PNGAPI
+png_set_bgr(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_bgr");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_BGR;
+}
+#endif
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Turn on 16-bit byte swapping */
+void PNGAPI
+png_set_swap(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_swap");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (png_ptr->bit_depth == 16)
+      png_ptr->transformations |= PNG_SWAP_BYTES;
+}
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+/* Turn on pixel packing */
+void PNGAPI
+png_set_packing(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_packing");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (png_ptr->bit_depth < 8)
+   {
+      png_ptr->transformations |= PNG_PACK;
+#     ifdef PNG_WRITE_SUPPORTED
+         png_ptr->usr_bit_depth = 8;
+#     endif
+   }
+}
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+/* Turn on packed pixel swapping */
+void PNGAPI
+png_set_packswap(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_packswap");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (png_ptr->bit_depth < 8)
+      png_ptr->transformations |= PNG_PACKSWAP;
+}
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+void PNGAPI
+png_set_shift(png_structrp png_ptr, png_const_color_8p true_bits)
+{
+   png_debug(1, "in png_set_shift");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_SHIFT;
+   png_ptr->shift = *true_bits;
+}
+#endif
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+    defined(PNG_WRITE_INTERLACING_SUPPORTED)
+int PNGAPI
+png_set_interlace_handling(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_interlace handling");
+
+   if (png_ptr != 0 && png_ptr->interlaced != 0)
+   {
+      png_ptr->transformations |= PNG_INTERLACE;
+      return 7;
+   }
+
+   return 1;
+}
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+/* Add a filler byte on read, or remove a filler or alpha byte on write.
+ * The filler type has changed in v0.95 to allow future 2-byte fillers
+ * for 48-bit input data, as well as to avoid problems with some compilers
+ * that don't like bytes as parameters.
+ */
+void PNGAPI
+png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
+{
+   png_debug(1, "in png_set_filler");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* In libpng 1.6 it is possible to determine whether this is a read or write
+    * operation and therefore to do more checking here for a valid call.
+    */
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+   {
+#     ifdef PNG_READ_FILLER_SUPPORTED
+         /* On read png_set_filler is always valid, regardless of the base PNG
+          * format, because other transformations can give a format where the
+          * filler code can execute (basically an 8 or 16-bit component RGB or G
+          * format.)
+          *
+          * NOTE: usr_channels is not used by the read code!  (This has led to
+          * confusion in the past.)  The filler is only used in the read code.
+          */
+         png_ptr->filler = (png_uint_16)filler;
+#     else
+         png_app_error(png_ptr, "png_set_filler not supported on read");
+         PNG_UNUSED(filler) /* not used in the write case */
+         return;
+#     endif
+   }
+
+   else /* write */
+   {
+#     ifdef PNG_WRITE_FILLER_SUPPORTED
+         /* On write the usr_channels parameter must be set correctly at the
+          * start to record the number of channels in the app-supplied data.
+          */
+         switch (png_ptr->color_type)
+         {
+            case PNG_COLOR_TYPE_RGB:
+               png_ptr->usr_channels = 4;
+               break;
+
+            case PNG_COLOR_TYPE_GRAY:
+               if (png_ptr->bit_depth >= 8)
+               {
+                  png_ptr->usr_channels = 2;
+                  break;
+               }
+
+               else
+               {
+                  /* There simply isn't any code in libpng to strip out bits
+                   * from bytes when the components are less than a byte in
+                   * size!
+                   */
+                  png_app_error(png_ptr,
+                      "png_set_filler is invalid for"
+                      " low bit depth gray output");
+                  return;
+               }
+
+            default:
+               png_app_error(png_ptr,
+                   "png_set_filler: inappropriate color type");
+               return;
+         }
+#     else
+         png_app_error(png_ptr, "png_set_filler not supported on write");
+         return;
+#     endif
+   }
+
+   /* Here on success - libpng supports the operation, set the transformation
+    * and the flag to say where the filler channel is.
+    */
+   png_ptr->transformations |= PNG_FILLER;
+
+   if (filler_loc == PNG_FILLER_AFTER)
+      png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
+
+   else
+      png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
+}
+
+/* Added to libpng-1.2.7 */
+void PNGAPI
+png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
+{
+   png_debug(1, "in png_set_add_alpha");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_set_filler(png_ptr, filler, filler_loc);
+   /* The above may fail to do anything. */
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
+      png_ptr->transformations |= PNG_ADD_ALPHA;
+}
+
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_swap_alpha(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_swap_alpha");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_SWAP_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_invert_alpha(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_invert_alpha");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_INVERT_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+void PNGAPI
+png_set_invert_mono(png_structrp png_ptr)
+{
+   png_debug(1, "in png_set_invert_mono");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_INVERT_MONO;
+}
+
+/* Invert monochrome grayscale data */
+void /* PRIVATE */
+png_do_invert(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_invert");
+
+  /* This test removed from libpng version 1.0.13 and 1.2.0:
+   *   if (row_info->bit_depth == 1 &&
+   */
+   if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      png_bytep rp = row;
+      size_t i;
+      size_t istop = row_info->rowbytes;
+
+      for (i = 0; i < istop; i++)
+      {
+         *rp = (png_byte)(~(*rp));
+         rp++;
+      }
+   }
+
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+      row_info->bit_depth == 8)
+   {
+      png_bytep rp = row;
+      size_t i;
+      size_t istop = row_info->rowbytes;
+
+      for (i = 0; i < istop; i += 2)
+      {
+         *rp = (png_byte)(~(*rp));
+         rp += 2;
+      }
+   }
+
+#ifdef PNG_16BIT_SUPPORTED
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+      row_info->bit_depth == 16)
+   {
+      png_bytep rp = row;
+      size_t i;
+      size_t istop = row_info->rowbytes;
+
+      for (i = 0; i < istop; i += 4)
+      {
+         *rp = (png_byte)(~(*rp));
+         *(rp + 1) = (png_byte)(~(*(rp + 1)));
+         rp += 4;
+      }
+   }
+#endif
+}
+#endif
+
+#ifdef PNG_16BIT_SUPPORTED
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Swaps byte order on 16-bit depth images */
+void /* PRIVATE */
+png_do_swap(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_swap");
+
+   if (row_info->bit_depth == 16)
+   {
+      png_bytep rp = row;
+      png_uint_32 i;
+      png_uint_32 istop= row_info->width * row_info->channels;
+
+      for (i = 0; i < istop; i++, rp += 2)
+      {
+#ifdef PNG_BUILTIN_BSWAP16_SUPPORTED
+         /* Feature added to libpng-1.6.11 for testing purposes, not
+          * enabled by default.
+          */
+         *(png_uint_16*)rp = __builtin_bswap16(*(png_uint_16*)rp);
+#else
+         png_byte t = *rp;
+         *rp = *(rp + 1);
+         *(rp + 1) = t;
+#endif
+      }
+   }
+}
+#endif
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+static const png_byte onebppswaptable[256] = {
+   0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
+   0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
+   0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
+   0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
+   0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
+   0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
+   0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
+   0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
+   0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
+   0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
+   0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
+   0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
+   0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
+   0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
+   0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
+   0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
+   0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
+   0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
+   0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
+   0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
+   0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
+   0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
+   0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
+   0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
+   0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
+   0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
+   0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
+   0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
+   0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
+   0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
+   0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
+   0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
+};
+
+static const png_byte twobppswaptable[256] = {
+   0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
+   0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
+   0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
+   0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
+   0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
+   0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
+   0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
+   0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
+   0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
+   0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
+   0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
+   0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
+   0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
+   0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
+   0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
+   0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
+   0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
+   0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
+   0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
+   0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
+   0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
+   0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
+   0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
+   0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
+   0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
+   0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
+   0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
+   0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
+   0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
+   0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
+   0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
+   0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
+};
+
+static const png_byte fourbppswaptable[256] = {
+   0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
+   0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
+   0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
+   0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
+   0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
+   0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
+   0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
+   0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
+   0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
+   0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
+   0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
+   0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
+   0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
+   0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
+   0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
+   0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
+   0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
+   0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
+   0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
+   0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
+   0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
+   0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
+   0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
+   0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
+   0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
+   0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
+   0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
+   0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
+   0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
+   0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
+   0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
+   0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
+};
+
+/* Swaps pixel packing order within bytes */
+void /* PRIVATE */
+png_do_packswap(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_packswap");
+
+   if (row_info->bit_depth < 8)
+   {
+      png_bytep rp;
+      png_const_bytep end, table;
+
+      end = row + row_info->rowbytes;
+
+      if (row_info->bit_depth == 1)
+         table = onebppswaptable;
+
+      else if (row_info->bit_depth == 2)
+         table = twobppswaptable;
+
+      else if (row_info->bit_depth == 4)
+         table = fourbppswaptable;
+
+      else
+         return;
+
+      for (rp = row; rp < end; rp++)
+         *rp = table[*rp];
+   }
+}
+#endif /* PACKSWAP || WRITE_PACKSWAP */
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+/* Remove a channel - this used to be 'png_do_strip_filler' but it used a
+ * somewhat weird combination of flags to determine what to do.  All the calls
+ * to png_do_strip_filler are changed in 1.5.2 to call this instead with the
+ * correct arguments.
+ *
+ * The routine isn't general - the channel must be the channel at the start or
+ * end (not in the middle) of each pixel.
+ */
+void /* PRIVATE */
+png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
+{
+   png_bytep sp = row; /* source pointer */
+   png_bytep dp = row; /* destination pointer */
+   png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */
+
+   png_debug(1, "in png_do_strip_channel");
+
+   /* At the start sp will point to the first byte to copy and dp to where
+    * it is copied to.  ep always points just beyond the end of the row, so
+    * the loop simply copies (channels-1) channels until sp reaches ep.
+    *
+    * at_start:        0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
+    *            nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
+    */
+
+   /* GA, GX, XG cases */
+   if (row_info->channels == 2)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         if (at_start != 0) /* Skip initial filler */
+            ++sp;
+         else          /* Skip initial channel and, for sp, the filler */
+         {
+            sp += 2; ++dp;
+         }
+
+         /* For a 1 pixel wide image there is nothing to do */
+         while (sp < ep)
+         {
+            *dp++ = *sp; sp += 2;
+         }
+
+         row_info->pixel_depth = 8;
+      }
+
+      else if (row_info->bit_depth == 16)
+      {
+         if (at_start != 0) /* Skip initial filler */
+            sp += 2;
+         else          /* Skip initial channel and, for sp, the filler */
+         {
+            sp += 4; dp += 2;
+         }
+
+         while (sp < ep)
+         {
+            *dp++ = *sp++; *dp++ = *sp; sp += 3;
+         }
+
+         row_info->pixel_depth = 16;
+      }
+
+      else
+         return; /* bad bit depth */
+
+      row_info->channels = 1;
+
+      /* Finally fix the color type if it records an alpha channel */
+      if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+         row_info->color_type = PNG_COLOR_TYPE_GRAY;
+   }
+
+   /* RGBA, RGBX, XRGB cases */
+   else if (row_info->channels == 4)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         if (at_start != 0) /* Skip initial filler */
+            ++sp;
+         else          /* Skip initial channels and, for sp, the filler */
+         {
+            sp += 4; dp += 3;
+         }
+
+         /* Note that the loop adds 3 to dp and 4 to sp each time. */
+         while (sp < ep)
+         {
+            *dp++ = *sp++; *dp++ = *sp++; *dp++ = *sp; sp += 2;
+         }
+
+         row_info->pixel_depth = 24;
+      }
+
+      else if (row_info->bit_depth == 16)
+      {
+         if (at_start != 0) /* Skip initial filler */
+            sp += 2;
+         else          /* Skip initial channels and, for sp, the filler */
+         {
+            sp += 8; dp += 6;
+         }
+
+         while (sp < ep)
+         {
+            /* Copy 6 bytes, skip 2 */
+            *dp++ = *sp++; *dp++ = *sp++;
+            *dp++ = *sp++; *dp++ = *sp++;
+            *dp++ = *sp++; *dp++ = *sp; sp += 3;
+         }
+
+         row_info->pixel_depth = 48;
+      }
+
+      else
+         return; /* bad bit depth */
+
+      row_info->channels = 3;
+
+      /* Finally fix the color type if it records an alpha channel */
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         row_info->color_type = PNG_COLOR_TYPE_RGB;
+   }
+
+   else
+      return; /* The filler channel has gone already */
+
+   /* Fix the rowbytes value. */
+   row_info->rowbytes = (size_t)(dp-row);
+}
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Swaps red and blue bytes within a pixel */
+void /* PRIVATE */
+png_do_bgr(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_bgr");
+
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_uint_32 row_width = row_info->width;
+      if (row_info->bit_depth == 8)
+      {
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 3)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 2);
+               *(rp + 2) = save;
+            }
+         }
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 4)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 2);
+               *(rp + 2) = save;
+            }
+         }
+      }
+
+#ifdef PNG_16BIT_SUPPORTED
+      else if (row_info->bit_depth == 16)
+      {
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 6)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 4);
+               *(rp + 4) = save;
+               save = *(rp + 1);
+               *(rp + 1) = *(rp + 5);
+               *(rp + 5) = save;
+            }
+         }
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 8)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 4);
+               *(rp + 4) = save;
+               save = *(rp + 1);
+               *(rp + 1) = *(rp + 5);
+               *(rp + 5) = save;
+            }
+         }
+      }
+#endif
+   }
+}
+#endif /* READ_BGR || WRITE_BGR */
+
+#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
+    defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
+/* Added at libpng-1.5.10 */
+void /* PRIVATE */
+png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
+{
+   png_debug(1, "in png_do_check_palette_indexes");
+
+   if (png_ptr->num_palette < (1 << row_info->bit_depth) &&
+      png_ptr->num_palette > 0) /* num_palette can be 0 in MNG files */
+   {
+      /* Calculations moved outside switch in an attempt to stop different
+       * compiler warnings.  'padding' is in *bits* within the last byte, it is
+       * an 'int' because pixel_depth becomes an 'int' in the expression below,
+       * and this calculation is used because it avoids warnings that other
+       * forms produced on either GCC or MSVC.
+       */
+      int padding = PNG_PADBITS(row_info->pixel_depth, row_info->width);
+      png_bytep rp = png_ptr->row_buf + row_info->rowbytes;
+
+      switch (row_info->bit_depth)
+      {
+         case 1:
+         {
+            /* in this case, all bytes must be 0 so we don't need
+             * to unpack the pixels except for the rightmost one.
+             */
+            for (; rp > png_ptr->row_buf; rp--)
+            {
+              if ((*rp >> padding) != 0)
+                 png_ptr->num_palette_max = 1;
+              padding = 0;
+            }
+
+            break;
+         }
+
+         case 2:
+         {
+            for (; rp > png_ptr->row_buf; rp--)
+            {
+              int i = ((*rp >> padding) & 0x03);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              i = (((*rp >> padding) >> 2) & 0x03);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              i = (((*rp >> padding) >> 4) & 0x03);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              i = (((*rp >> padding) >> 6) & 0x03);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              padding = 0;
+            }
+
+            break;
+         }
+
+         case 4:
+         {
+            for (; rp > png_ptr->row_buf; rp--)
+            {
+              int i = ((*rp >> padding) & 0x0f);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              i = (((*rp >> padding) >> 4) & 0x0f);
+
+              if (i > png_ptr->num_palette_max)
+                 png_ptr->num_palette_max = i;
+
+              padding = 0;
+            }
+
+            break;
+         }
+
+         case 8:
+         {
+            for (; rp > png_ptr->row_buf; rp--)
+            {
+               if (*rp > png_ptr->num_palette_max)
+                  png_ptr->num_palette_max = (int) *rp;
+            }
+
+            break;
+         }
+
+         default:
+            break;
+      }
+   }
+}
+#endif /* CHECK_FOR_INVALID_INDEX */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+void PNGAPI
+png_set_user_transform_info(png_structrp png_ptr, png_voidp
+   user_transform_ptr, int user_transform_depth, int user_transform_channels)
+{
+   png_debug(1, "in png_set_user_transform_info");
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+   if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+      (png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
+   {
+      png_app_error(png_ptr,
+          "info change after png_start_read_image or png_read_update_info");
+      return;
+   }
+#endif
+
+   png_ptr->user_transform_ptr = user_transform_ptr;
+   png_ptr->user_transform_depth = (png_byte)user_transform_depth;
+   png_ptr->user_transform_channels = (png_byte)user_transform_channels;
+}
+#endif
+
+/* This function returns a pointer to the user_transform_ptr associated with
+ * the user transform functions.  The application should free any memory
+ * associated with this pointer before png_write_destroy and png_read_destroy
+ * are called.
+ */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+png_voidp PNGAPI
+png_get_user_transform_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return NULL;
+
+   return png_ptr->user_transform_ptr;
+}
+#endif
+
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+png_uint_32 PNGAPI
+png_get_current_row_number(png_const_structrp png_ptr)
+{
+   /* See the comments in png.h - this is the sub-image row when reading an
+    * interlaced image.
+    */
+   if (png_ptr != NULL)
+      return png_ptr->row_number;
+
+   return PNG_UINT_32_MAX; /* help the app not to fail silently */
+}
+
+png_byte PNGAPI
+png_get_current_pass_number(png_const_structrp png_ptr)
+{
+   if (png_ptr != NULL)
+      return png_ptr->pass;
+   return 8; /* invalid */
+}
+#endif /* USER_TRANSFORM_INFO */
+#endif /* READ_USER_TRANSFORM || WRITE_USER_TRANSFORM */
+#endif /* READ || WRITE */
Index: /trunk/src/libs/libpng-1.6.45/pngusr.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngusr.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngusr.dfa	(revision 107811)
@@ -0,0 +1,14 @@
+# pngusr.dfa
+#
+# Build time configuration of libpng
+#
+# Enter build configuration options in this file
+#
+# Security settings: by default these limits are unset, you can change them
+# here by entering the appropriate values as #defines preceded by '@' (to cause,
+# them to be passed through to the build of pnglibconf.h), for example:
+#
+# @# define PNG_USER_WIDTH_MAX 65535
+# @# define PNG_USER_HEIGHT_MAX 65535
+# @# define PNG_USER_CHUNK_CACHE_MAX 256
+# @# define PNG_USER_CHUNK_MALLOC_MAX 640000
Index: /trunk/src/libs/libpng-1.6.45/pngwio.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngwio.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngwio.c	(revision 107811)
@@ -0,0 +1,168 @@
+
+/* pngwio.c - functions for data output
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2014,2016,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all output.  Users who need
+ * special handling are expected to write functions that have the same
+ * arguments as these and perform similar functions, but that possibly
+ * use different output methods.  Note that you shouldn't change these
+ * functions, but rather write replacement functions and then change
+ * them at run time with png_set_write_fn(...).
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Write the data to whatever output you are using.  The default routine
+ * writes to a file pointer.  Note that this routine sometimes gets called
+ * with very small lengths, so you should implement some kind of simple
+ * buffering if you are using unbuffered writes.  This should never be asked
+ * to write more than 64K on a 16-bit machine.
+ */
+
+void /* PRIVATE */
+png_write_data(png_structrp png_ptr, png_const_bytep data, size_t length)
+{
+   /* NOTE: write_data_fn must not change the buffer! */
+   if (png_ptr->write_data_fn != NULL )
+      (*(png_ptr->write_data_fn))(png_ptr, png_constcast(png_bytep,data),
+          length);
+
+   else
+      png_error(png_ptr, "Call to NULL write function");
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+/* This is the function that does the actual writing of data.  If you are
+ * not writing to a standard C stream, you should create a replacement
+ * write_data function and use it at run time with png_set_write_fn(), rather
+ * than changing the library.
+ */
+void PNGCBAPI
+png_default_write_data(png_structp png_ptr, png_bytep data, size_t length)
+{
+   size_t check;
+
+   if (png_ptr == NULL)
+      return;
+
+   check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
+
+   if (check != length)
+      png_error(png_ptr, "Write Error");
+}
+#endif
+
+/* This function is called to output any data pending writing (normally
+ * to disk).  After png_flush is called, there should be no data pending
+ * writing in any buffers.
+ */
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+void /* PRIVATE */
+png_flush(png_structrp png_ptr)
+{
+   if (png_ptr->output_flush_fn != NULL)
+      (*(png_ptr->output_flush_fn))(png_ptr);
+}
+
+#  ifdef PNG_STDIO_SUPPORTED
+void PNGCBAPI
+png_default_flush(png_structp png_ptr)
+{
+   png_FILE_p io_ptr;
+
+   if (png_ptr == NULL)
+      return;
+
+   io_ptr = png_voidcast(png_FILE_p, (png_ptr->io_ptr));
+   fflush(io_ptr);
+}
+#  endif
+#endif
+
+/* This function allows the application to supply new output functions for
+ * libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ * png_ptr       - pointer to a png output data structure
+ * io_ptr        - pointer to user supplied structure containing info about
+ *                 the output functions.  May be NULL.
+ * write_data_fn - pointer to a new output function that takes as its
+ *                 arguments a pointer to a png_struct, a pointer to
+ *                 data to be written, and a 32-bit unsigned int that is
+ *                 the number of bytes to be written.  The new write
+ *                 function should call png_error(png_ptr, "Error msg")
+ *                 to exit and output any fatal error messages.  May be
+ *                 NULL, in which case libpng's default function will
+ *                 be used.
+ * flush_data_fn - pointer to a new flush function that takes as its
+ *                 arguments a pointer to a png_struct.  After a call to
+ *                 the flush function, there should be no data in any buffers
+ *                 or pending transmission.  If the output method doesn't do
+ *                 any buffering of output, a function prototype must still be
+ *                 supplied although it doesn't have to do anything.  If
+ *                 PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
+ *                 time, output_flush_fn will be ignored, although it must be
+ *                 supplied for compatibility.  May be NULL, in which case
+ *                 libpng's default function will be used, if
+ *                 PNG_WRITE_FLUSH_SUPPORTED is defined.  This is not
+ *                 a good idea if io_ptr does not point to a standard
+ *                 *FILE structure.
+ */
+void PNGAPI
+png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr,
+    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
+{
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->io_ptr = io_ptr;
+
+#ifdef PNG_STDIO_SUPPORTED
+   if (write_data_fn != NULL)
+      png_ptr->write_data_fn = write_data_fn;
+
+   else
+      png_ptr->write_data_fn = png_default_write_data;
+#else
+   png_ptr->write_data_fn = write_data_fn;
+#endif
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+#  ifdef PNG_STDIO_SUPPORTED
+
+   if (output_flush_fn != NULL)
+      png_ptr->output_flush_fn = output_flush_fn;
+
+   else
+      png_ptr->output_flush_fn = png_default_flush;
+
+#  else
+   png_ptr->output_flush_fn = output_flush_fn;
+#  endif
+#else
+   PNG_UNUSED(output_flush_fn)
+#endif /* WRITE_FLUSH */
+
+#ifdef PNG_READ_SUPPORTED
+   /* It is an error to read while writing a png file */
+   if (png_ptr->read_data_fn != NULL)
+   {
+      png_ptr->read_data_fn = NULL;
+
+      png_warning(png_ptr,
+          "Can't set both read_data_fn and write_data_fn in the"
+          " same structure");
+   }
+#endif
+}
+#endif /* WRITE */
Index: /trunk/src/libs/libpng-1.6.45/pngwrite.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngwrite.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngwrite.c	(revision 107811)
@@ -0,0 +1,2418 @@
+
+/* pngwrite.c - general routines to write a PNG file
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+#  include <errno.h>
+#endif /* SIMPLIFIED_WRITE_STDIO */
+
+#ifdef PNG_WRITE_SUPPORTED
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+/* Write out all the unknown chunks for the current given location */
+static void
+write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
+    unsigned int where)
+{
+   if (info_ptr->unknown_chunks_num != 0)
+   {
+      png_const_unknown_chunkp up;
+
+      png_debug(5, "writing extra chunks");
+
+      for (up = info_ptr->unknown_chunks;
+           up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
+           ++up)
+         if ((up->location & where) != 0)
+      {
+         /* If per-chunk unknown chunk handling is enabled use it, otherwise
+          * just write the chunks the application has set.
+          */
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+         int keep = png_handle_as_unknown(png_ptr, up->name);
+
+         /* NOTE: this code is radically different from the read side in the
+          * matter of handling an ancillary unknown chunk.  In the read side
+          * the default behavior is to discard it, in the code below the default
+          * behavior is to write it.  Critical chunks are, however, only
+          * written if explicitly listed or if the default is set to write all
+          * unknown chunks.
+          *
+          * The default handling is also slightly weird - it is not possible to
+          * stop the writing of all unsafe-to-copy chunks!
+          *
+          * TODO: REVIEW: this would seem to be a bug.
+          */
+         if (keep != PNG_HANDLE_CHUNK_NEVER &&
+             ((up->name[3] & 0x20) /* safe-to-copy overrides everything */ ||
+              keep == PNG_HANDLE_CHUNK_ALWAYS ||
+              (keep == PNG_HANDLE_CHUNK_AS_DEFAULT &&
+               png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS)))
+#endif
+         {
+            /* TODO: review, what is wrong with a zero length unknown chunk? */
+            if (up->size == 0)
+               png_warning(png_ptr, "Writing zero-length unknown chunk");
+
+            png_write_chunk(png_ptr, up->name, up->data, up->size);
+         }
+      }
+   }
+}
+#endif /* WRITE_UNKNOWN_CHUNKS */
+
+/* Writes all the PNG information.  This is the suggested way to use the
+ * library.  If you have a new chunk to add, make a function to write it,
+ * and put it in the correct location here.  If you want the chunk written
+ * after the image data, put it in png_write_end().  I strongly encourage
+ * you to supply a PNG_INFO_<chunk> flag, and check info_ptr->valid before
+ * writing the chunk, as that will keep the code from breaking if you want
+ * to just write a plain PNG file.  If you have long comments, I suggest
+ * writing them in png_write_end(), and compressing them.
+ */
+void PNGAPI
+png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
+{
+   png_debug(1, "in png_write_info_before_PLTE");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
+   {
+      /* Write PNG signature */
+      png_write_sig(png_ptr);
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+      if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
+          png_ptr->mng_features_permitted != 0)
+      {
+         png_warning(png_ptr,
+             "MNG features are not allowed in a PNG datastream");
+         png_ptr->mng_features_permitted = 0;
+      }
+#endif
+
+      /* Write IHDR information. */
+      png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
+          info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
+          info_ptr->filter_type,
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+          info_ptr->interlace_type
+#else
+          0
+#endif
+         );
+
+      /* The rest of these check to see if the valid field has the appropriate
+       * flag set, and if it does, writes the chunk.
+       *
+       * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
+       * the chunks will be written if the WRITE routine is there and
+       * information * is available in the COLORSPACE. (See
+       * png_colorspace_sync_info in png.c for where the valid flags get set.)
+       *
+       * Under certain circumstances the colorspace can be invalidated without
+       * syncing the info_struct 'valid' flags; this happens if libpng detects
+       * an error and calls png_error while the color space is being set, yet
+       * the application continues writing the PNG.  So check the 'invalid'
+       * flag here too.
+       */
+#ifdef PNG_GAMMA_SUPPORTED
+#  ifdef PNG_WRITE_gAMA_SUPPORTED
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+          (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
+          (info_ptr->valid & PNG_INFO_gAMA) != 0)
+         png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
+#  endif
+#endif
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+      /* Write only one of sRGB or an ICC profile.  If a profile was supplied
+       * and it matches one of the known sRGB ones issue a warning.
+       */
+#  ifdef PNG_WRITE_iCCP_SUPPORTED
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+             (info_ptr->valid & PNG_INFO_iCCP) != 0)
+         {
+#    ifdef PNG_WRITE_sRGB_SUPPORTED
+               if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
+                  png_app_warning(png_ptr,
+                      "profile matches sRGB but writing iCCP instead");
+#     endif
+
+            png_write_iCCP(png_ptr, info_ptr->iccp_name,
+                info_ptr->iccp_profile);
+         }
+#     ifdef PNG_WRITE_sRGB_SUPPORTED
+         else
+#     endif
+#  endif
+
+#  ifdef PNG_WRITE_sRGB_SUPPORTED
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+             (info_ptr->valid & PNG_INFO_sRGB) != 0)
+            png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
+#  endif /* WRITE_sRGB */
+#endif /* COLORSPACE */
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+         if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+            png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
+#endif
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+#  ifdef PNG_WRITE_cHRM_SUPPORTED
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+             (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
+             (info_ptr->valid & PNG_INFO_cHRM) != 0)
+            png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
+#  endif
+#endif
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+         write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
+#endif
+
+      png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
+   }
+}
+
+void PNGAPI
+png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
+{
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+   int i;
+#endif
+
+   png_debug(1, "in png_write_info");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_write_info_before_PLTE(png_ptr, info_ptr);
+
+   if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
+      png_write_PLTE(png_ptr, info_ptr->palette,
+          (png_uint_32)info_ptr->num_palette);
+
+   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      png_error(png_ptr, "Valid palette required for paletted images");
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
+   {
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+      /* Invert the alpha channel (in tRNS) */
+      if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
+          info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         int j, jend;
+
+         jend = info_ptr->num_trans;
+         if (jend > PNG_MAX_PALETTE_LENGTH)
+            jend = PNG_MAX_PALETTE_LENGTH;
+
+         for (j = 0; j<jend; ++j)
+            info_ptr->trans_alpha[j] =
+               (png_byte)(255 - info_ptr->trans_alpha[j]);
+      }
+#endif
+      png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
+          info_ptr->num_trans, info_ptr->color_type);
+   }
+#endif
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
+      png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
+#endif
+
+#ifdef PNG_WRITE_eXIf_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
+   {
+      png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
+      png_ptr->mode |= PNG_WROTE_eXIf;
+   }
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_hIST) != 0)
+      png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
+      png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
+          info_ptr->offset_unit_type);
+#endif
+
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
+      png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
+          info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
+          info_ptr->pcal_units, info_ptr->pcal_params);
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
+      png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
+          info_ptr->scal_s_width, info_ptr->scal_s_height);
+#endif /* sCAL */
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
+      png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
+          info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
+#endif /* pHYs */
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_tIME) != 0)
+   {
+      png_write_tIME(png_ptr, &(info_ptr->mod_time));
+      png_ptr->mode |= PNG_WROTE_tIME;
+   }
+#endif /* tIME */
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+   if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
+      for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
+         png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
+#endif /* sPLT */
+
+#ifdef PNG_WRITE_TEXT_SUPPORTED
+   /* Check to see if we need to write text chunks */
+   for (i = 0; i < info_ptr->num_text; i++)
+   {
+      png_debug2(2, "Writing header text chunk %d, type %d", i,
+          info_ptr->text[i].compression);
+      /* An internationalized chunk? */
+      if (info_ptr->text[i].compression > 0)
+      {
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+         /* Write international chunk */
+         png_write_iTXt(png_ptr,
+             info_ptr->text[i].compression,
+             info_ptr->text[i].key,
+             info_ptr->text[i].lang,
+             info_ptr->text[i].lang_key,
+             info_ptr->text[i].text);
+         /* Mark this chunk as written */
+         if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+         else
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+         png_warning(png_ptr, "Unable to write international text");
+#endif
+      }
+
+      /* If we want a compressed text chunk */
+      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
+      {
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+         /* Write compressed chunk */
+         png_write_zTXt(png_ptr, info_ptr->text[i].key,
+             info_ptr->text[i].text, info_ptr->text[i].compression);
+         /* Mark this chunk as written */
+         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+         png_warning(png_ptr, "Unable to write compressed text");
+#endif
+      }
+
+      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+      {
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+         /* Write uncompressed chunk */
+         png_write_tEXt(png_ptr, info_ptr->text[i].key,
+             info_ptr->text[i].text,
+             0);
+         /* Mark this chunk as written */
+         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+#else
+         /* Can't get here */
+         png_warning(png_ptr, "Unable to write uncompressed text");
+#endif
+      }
+   }
+#endif /* tEXt */
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+   write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
+#endif
+}
+
+/* Writes the end of the PNG file.  If you don't want to write comments or
+ * time information, you can pass NULL for info.  If you already wrote these
+ * in png_write_info(), do not write them again here.  If you have long
+ * comments, I suggest writing them here, and compressing them.
+ */
+void PNGAPI
+png_write_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+   png_debug(1, "in png_write_end");
+
+   if (png_ptr == NULL)
+      return;
+
+   if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+      png_error(png_ptr, "No IDATs written into file");
+
+#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+       png_ptr->num_palette_max >= png_ptr->num_palette)
+      png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
+#endif
+
+   /* See if user wants us to write information chunks */
+   if (info_ptr != NULL)
+   {
+#ifdef PNG_WRITE_TEXT_SUPPORTED
+      int i; /* local index variable */
+#endif
+#ifdef PNG_WRITE_tIME_SUPPORTED
+      /* Check to see if user has supplied a time chunk */
+      if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
+          (png_ptr->mode & PNG_WROTE_tIME) == 0)
+         png_write_tIME(png_ptr, &(info_ptr->mod_time));
+
+#endif
+#ifdef PNG_WRITE_TEXT_SUPPORTED
+      /* Loop through comment chunks */
+      for (i = 0; i < info_ptr->num_text; i++)
+      {
+         png_debug2(2, "Writing trailer text chunk %d, type %d", i,
+             info_ptr->text[i].compression);
+         /* An internationalized chunk? */
+         if (info_ptr->text[i].compression > 0)
+         {
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+            /* Write international chunk */
+            png_write_iTXt(png_ptr,
+                info_ptr->text[i].compression,
+                info_ptr->text[i].key,
+                info_ptr->text[i].lang,
+                info_ptr->text[i].lang_key,
+                info_ptr->text[i].text);
+            /* Mark this chunk as written */
+            if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+            else
+               info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+            png_warning(png_ptr, "Unable to write international text");
+#endif
+         }
+
+         else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
+         {
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+            /* Write compressed chunk */
+            png_write_zTXt(png_ptr, info_ptr->text[i].key,
+                info_ptr->text[i].text, info_ptr->text[i].compression);
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+            png_warning(png_ptr, "Unable to write compressed text");
+#endif
+         }
+
+         else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+         {
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+            /* Write uncompressed chunk */
+            png_write_tEXt(png_ptr, info_ptr->text[i].key,
+                info_ptr->text[i].text, 0);
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+#else
+            png_warning(png_ptr, "Unable to write uncompressed text");
+#endif
+         }
+      }
+#endif
+
+#ifdef PNG_WRITE_eXIf_SUPPORTED
+      if ((info_ptr->valid & PNG_INFO_eXIf) != 0 &&
+          (png_ptr->mode & PNG_WROTE_eXIf) == 0)
+         png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
+#endif
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+      write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
+#endif
+   }
+
+   png_ptr->mode |= PNG_AFTER_IDAT;
+
+   /* Write end of PNG file */
+   png_write_IEND(png_ptr);
+
+   /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
+    * and restored again in libpng-1.2.30, may cause some applications that
+    * do not set png_ptr->output_flush_fn to crash.  If your application
+    * experiences a problem, please try building libpng with
+    * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
+    * png-mng-implement at lists.sf.net .
+    */
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+#  ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
+   png_flush(png_ptr);
+#  endif
+#endif
+}
+
+#ifdef PNG_CONVERT_tIME_SUPPORTED
+void PNGAPI
+png_convert_from_struct_tm(png_timep ptime, const struct tm * ttime)
+{
+   png_debug(1, "in png_convert_from_struct_tm");
+
+   ptime->year = (png_uint_16)(1900 + ttime->tm_year);
+   ptime->month = (png_byte)(ttime->tm_mon + 1);
+   ptime->day = (png_byte)ttime->tm_mday;
+   ptime->hour = (png_byte)ttime->tm_hour;
+   ptime->minute = (png_byte)ttime->tm_min;
+   ptime->second = (png_byte)ttime->tm_sec;
+}
+
+void PNGAPI
+png_convert_from_time_t(png_timep ptime, time_t ttime)
+{
+   struct tm *tbuf;
+
+   png_debug(1, "in png_convert_from_time_t");
+
+   tbuf = gmtime(&ttime);
+   if (tbuf == NULL)
+   {
+      /* TODO: add a safe function which takes a png_ptr argument and raises
+       * a png_error if the ttime argument is invalid and the call to gmtime
+       * fails as a consequence.
+       */
+      memset(ptime, 0, sizeof(*ptime));
+      return;
+   }
+
+   png_convert_from_struct_tm(ptime, tbuf);
+}
+#endif
+
+/* Initialize png_ptr structure, and allocate any memory needed */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
+{
+#ifndef PNG_USER_MEM_SUPPORTED
+   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+       error_fn, warn_fn, NULL, NULL, NULL);
+#else
+   return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
+       warn_fn, NULL, NULL, NULL);
+}
+
+/* Alternate initialize png_ptr structure, and allocate any memory needed */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
+    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+    png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
+{
+   png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+       error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
+#endif /* USER_MEM */
+   if (png_ptr != NULL)
+   {
+      /* Set the zlib control values to defaults; they can be overridden by the
+       * application after the struct has been created.
+       */
+      png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
+
+      /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
+       * pngwutil.c defaults it according to whether or not filters will be
+       * used, and ignores this setting.
+       */
+      png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
+      png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
+      png_ptr->zlib_mem_level = 8;
+      png_ptr->zlib_window_bits = 15;
+      png_ptr->zlib_method = 8;
+
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+      png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
+      png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
+      png_ptr->zlib_text_mem_level = 8;
+      png_ptr->zlib_text_window_bits = 15;
+      png_ptr->zlib_text_method = 8;
+#endif /* WRITE_COMPRESSED_TEXT */
+
+      /* This is a highly dubious configuration option; by default it is off,
+       * but it may be appropriate for private builds that are testing
+       * extensions not conformant to the current specification, or of
+       * applications that must not fail to write at all costs!
+       */
+#ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
+      /* In stable builds only warn if an application error can be completely
+       * handled.
+       */
+      png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
+#endif
+
+      /* App warnings are warnings in release (or release candidate) builds but
+       * are errors during development.
+       */
+#if PNG_RELEASE_BUILD
+      png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
+#endif
+
+      /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
+       * do it itself) avoiding setting the default function if it is not
+       * required.
+       */
+      png_set_write_fn(png_ptr, NULL, NULL, NULL);
+   }
+
+   return png_ptr;
+}
+
+
+/* Write a few rows of image data.  If the image is interlaced,
+ * either you will have to write the 7 sub images, or, if you
+ * have called png_set_interlace_handling(), you will have to
+ * "write" the image seven times.
+ */
+void PNGAPI
+png_write_rows(png_structrp png_ptr, png_bytepp row,
+    png_uint_32 num_rows)
+{
+   png_uint_32 i; /* row counter */
+   png_bytepp rp; /* row pointer */
+
+   png_debug(1, "in png_write_rows");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* Loop through the rows */
+   for (i = 0, rp = row; i < num_rows; i++, rp++)
+   {
+      png_write_row(png_ptr, *rp);
+   }
+}
+
+/* Write the image.  You only need to call this function once, even
+ * if you are writing an interlaced image.
+ */
+void PNGAPI
+png_write_image(png_structrp png_ptr, png_bytepp image)
+{
+   png_uint_32 i; /* row index */
+   int pass, num_pass; /* pass variables */
+   png_bytepp rp; /* points to current row */
+
+   if (png_ptr == NULL)
+      return;
+
+   png_debug(1, "in png_write_image");
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* Initialize interlace handling.  If image is not interlaced,
+    * this will set pass to 1
+    */
+   num_pass = png_set_interlace_handling(png_ptr);
+#else
+   num_pass = 1;
+#endif
+   /* Loop through passes */
+   for (pass = 0; pass < num_pass; pass++)
+   {
+      /* Loop through image */
+      for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
+      {
+         png_write_row(png_ptr, *rp);
+      }
+   }
+}
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Performs intrapixel differencing  */
+static void
+png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_intrapixel");
+
+   if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      int bytes_per_pixel;
+      png_uint_32 row_width = row_info->width;
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 3;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 4;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            *(rp)     = (png_byte)(*rp       - *(rp + 1));
+            *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
+         }
+      }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+      else if (row_info->bit_depth == 16)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 6;
+
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 8;
+
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            png_uint_32 s0   = (png_uint_32)(*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 red  = (png_uint_32)((s0 - s1) & 0xffffL);
+            png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
+            *(rp    ) = (png_byte)(red >> 8);
+            *(rp + 1) = (png_byte)red;
+            *(rp + 4) = (png_byte)(blue >> 8);
+            *(rp + 5) = (png_byte)blue;
+         }
+      }
+#endif /* WRITE_16BIT */
+   }
+}
+#endif /* MNG_FEATURES */
+
+/* Called by user to write a row of image data */
+void PNGAPI
+png_write_row(png_structrp png_ptr, png_const_bytep row)
+{
+   /* 1.5.6: moved from png_struct to be a local structure: */
+   png_row_info row_info;
+
+   png_debug2(1, "in png_write_row (row %u, pass %d)",
+       png_ptr->row_number, png_ptr->pass);
+
+   if (png_ptr == NULL)
+      return;
+
+   /* Initialize transformations and other stuff if first time */
+   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
+   {
+      /* Make sure we wrote the header info */
+      if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
+         png_error(png_ptr,
+             "png_write_info was never called before png_write_row");
+
+      /* Check for transforms that have been set but were defined out */
+#if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
+      if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+         png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
+      if ((png_ptr->transformations & PNG_FILLER) != 0)
+         png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
+#endif
+#if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
+    defined(PNG_READ_PACKSWAP_SUPPORTED)
+      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+         png_warning(png_ptr,
+             "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
+      if ((png_ptr->transformations & PNG_PACK) != 0)
+         png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
+      if ((png_ptr->transformations & PNG_SHIFT) != 0)
+         png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
+      if ((png_ptr->transformations & PNG_BGR) != 0)
+         png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
+      if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+         png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
+#endif
+
+      png_write_start_row(png_ptr);
+   }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* If interlaced and not interested in row, return */
+   if (png_ptr->interlaced != 0 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      switch (png_ptr->pass)
+      {
+         case 0:
+            if ((png_ptr->row_number & 0x07) != 0)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 1:
+            if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 2:
+            if ((png_ptr->row_number & 0x07) != 4)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 3:
+            if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 4:
+            if ((png_ptr->row_number & 0x03) != 2)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 5:
+            if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         case 6:
+            if ((png_ptr->row_number & 0x01) == 0)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+
+         default: /* error: ignore it */
+            break;
+      }
+   }
+#endif
+
+   /* Set up row info for transformations */
+   row_info.color_type = png_ptr->color_type;
+   row_info.width = png_ptr->usr_width;
+   row_info.channels = png_ptr->usr_channels;
+   row_info.bit_depth = png_ptr->usr_bit_depth;
+   row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
+   row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+   png_debug1(3, "row_info->color_type = %d", row_info.color_type);
+   png_debug1(3, "row_info->width = %u", row_info.width);
+   png_debug1(3, "row_info->channels = %d", row_info.channels);
+   png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
+   png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
+   png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
+
+   /* Copy user's row into buffer, leaving room for filter byte. */
+   memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* Handle interlacing */
+   if (png_ptr->interlaced && png_ptr->pass < 6 &&
+       (png_ptr->transformations & PNG_INTERLACE) != 0)
+   {
+      png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
+      /* This should always get caught above, but still ... */
+      if (row_info.width == 0)
+      {
+         png_write_finish_row(png_ptr);
+         return;
+      }
+   }
+#endif
+
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+   /* Handle other transformations */
+   if (png_ptr->transformations != 0)
+      png_do_write_transformations(png_ptr, &row_info);
+#endif
+
+   /* At this point the row_info pixel depth must match the 'transformed' depth,
+    * which is also the output depth.
+    */
+   if (row_info.pixel_depth != png_ptr->pixel_depth ||
+       row_info.pixel_depth != png_ptr->transformed_pixel_depth)
+      png_error(png_ptr, "internal write transform logic error");
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   /* Write filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not write a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
+   {
+      /* Intrapixel differencing */
+      png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
+   }
+#endif
+
+/* Added at libpng-1.5.10 */
+#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+   /* Check for out-of-range palette index */
+   if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
+       png_ptr->num_palette_max >= 0)
+      png_do_check_palette_indexes(png_ptr, &row_info);
+#endif
+
+   /* Find a filter if necessary, filter the row and write it out. */
+   png_write_find_filter(png_ptr, &row_info);
+
+   if (png_ptr->write_row_fn != NULL)
+      (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
+}
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+/* Set the automatic flush interval or 0 to turn flushing off */
+void PNGAPI
+png_set_flush(png_structrp png_ptr, int nrows)
+{
+   png_debug(1, "in png_set_flush");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows);
+}
+
+/* Flush the current output buffers now */
+void PNGAPI
+png_write_flush(png_structrp png_ptr)
+{
+   png_debug(1, "in png_write_flush");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* We have already written out all of the data */
+   if (png_ptr->row_number >= png_ptr->num_rows)
+      return;
+
+   png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
+   png_ptr->flush_rows = 0;
+   png_flush(png_ptr);
+}
+#endif /* WRITE_FLUSH */
+
+/* Free any memory used in png_ptr struct without freeing the struct itself. */
+static void
+png_write_destroy(png_structrp png_ptr)
+{
+   png_debug(1, "in png_write_destroy");
+
+   /* Free any memory zlib uses */
+   if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+      deflateEnd(&png_ptr->zstream);
+
+   /* Free our memory.  png_free checks NULL for us. */
+   png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
+   png_free(png_ptr, png_ptr->row_buf);
+   png_ptr->row_buf = NULL;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   png_free(png_ptr, png_ptr->prev_row);
+   png_free(png_ptr, png_ptr->try_row);
+   png_free(png_ptr, png_ptr->tst_row);
+   png_ptr->prev_row = NULL;
+   png_ptr->try_row = NULL;
+   png_ptr->tst_row = NULL;
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+   png_free(png_ptr, png_ptr->chunk_list);
+   png_ptr->chunk_list = NULL;
+#endif
+
+   /* The error handling and memory handling information is left intact at this
+    * point: the jmp_buf may still have to be freed.  See png_destroy_png_struct
+    * for how this happens.
+    */
+}
+
+/* Free all memory used by the write.
+ * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
+ * *png_ptr_ptr.  Prior to 1.6.0 it would accept such a value and it would free
+ * the passed in info_structs but it would quietly fail to free any of the data
+ * inside them.  In 1.6.0 it quietly does nothing (it has to be quiet because it
+ * has no png_ptr.)
+ */
+void PNGAPI
+png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
+{
+   png_debug(1, "in png_destroy_write_struct");
+
+   if (png_ptr_ptr != NULL)
+   {
+      png_structrp png_ptr = *png_ptr_ptr;
+
+      if (png_ptr != NULL) /* added in libpng 1.6.0 */
+      {
+         png_destroy_info_struct(png_ptr, info_ptr_ptr);
+
+         *png_ptr_ptr = NULL;
+         png_write_destroy(png_ptr);
+         png_destroy_png_struct(png_ptr);
+      }
+   }
+}
+
+/* Allow the application to select one or more row filters to use. */
+void PNGAPI
+png_set_filter(png_structrp png_ptr, int method, int filters)
+{
+   png_debug(1, "in png_set_filter");
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       (method == PNG_INTRAPIXEL_DIFFERENCING))
+      method = PNG_FILTER_TYPE_BASE;
+
+#endif
+   if (method == PNG_FILTER_TYPE_BASE)
+   {
+      switch (filters & (PNG_ALL_FILTERS | 0x07))
+      {
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         case 5:
+         case 6:
+         case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
+#endif /* WRITE_FILTER */
+            /* FALLTHROUGH */
+         case PNG_FILTER_VALUE_NONE:
+            png_ptr->do_filter = PNG_FILTER_NONE; break;
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+         case PNG_FILTER_VALUE_SUB:
+            png_ptr->do_filter = PNG_FILTER_SUB; break;
+
+         case PNG_FILTER_VALUE_UP:
+            png_ptr->do_filter = PNG_FILTER_UP; break;
+
+         case PNG_FILTER_VALUE_AVG:
+            png_ptr->do_filter = PNG_FILTER_AVG; break;
+
+         case PNG_FILTER_VALUE_PAETH:
+            png_ptr->do_filter = PNG_FILTER_PAETH; break;
+
+         default:
+            png_ptr->do_filter = (png_byte)filters; break;
+#else
+         default:
+            png_app_error(png_ptr, "Unknown row filter for method 0");
+#endif /* WRITE_FILTER */
+      }
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+      /* If we have allocated the row_buf, this means we have already started
+       * with the image and we should have allocated all of the filter buffers
+       * that have been selected.  If prev_row isn't already allocated, then
+       * it is too late to start using the filters that need it, since we
+       * will be missing the data in the previous row.  If an application
+       * wants to start and stop using particular filters during compression,
+       * it should start out with all of the filters, and then remove them
+       * or add them back after the start of compression.
+       *
+       * NOTE: this is a nasty constraint on the code, because it means that the
+       * prev_row buffer must be maintained even if there are currently no
+       * 'prev_row' requiring filters active.
+       */
+      if (png_ptr->row_buf != NULL)
+      {
+         int num_filters;
+         png_alloc_size_t buf_size;
+
+         /* Repeat the checks in png_write_start_row; 1 pixel high or wide
+          * images cannot benefit from certain filters.  If this isn't done here
+          * the check below will fire on 1 pixel high images.
+          */
+         if (png_ptr->height == 1)
+            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+         if (png_ptr->width == 1)
+            filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+         if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
+            && png_ptr->prev_row == NULL)
+         {
+            /* This is the error case, however it is benign - the previous row
+             * is not available so the filter can't be used.  Just warn here.
+             */
+            png_app_warning(png_ptr,
+                "png_set_filter: UP/AVG/PAETH cannot be added after start");
+            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+         }
+
+         num_filters = 0;
+
+         if (filters & PNG_FILTER_SUB)
+            num_filters++;
+
+         if (filters & PNG_FILTER_UP)
+            num_filters++;
+
+         if (filters & PNG_FILTER_AVG)
+            num_filters++;
+
+         if (filters & PNG_FILTER_PAETH)
+            num_filters++;
+
+         /* Allocate needed row buffers if they have not already been
+          * allocated.
+          */
+         buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
+             png_ptr->width) + 1;
+
+         if (png_ptr->try_row == NULL)
+            png_ptr->try_row = png_voidcast(png_bytep,
+                png_malloc(png_ptr, buf_size));
+
+         if (num_filters > 1)
+         {
+            if (png_ptr->tst_row == NULL)
+               png_ptr->tst_row = png_voidcast(png_bytep,
+                   png_malloc(png_ptr, buf_size));
+         }
+      }
+      png_ptr->do_filter = (png_byte)filters;
+#endif
+   }
+   else
+      png_error(png_ptr, "Unknown custom filter method");
+}
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
+/* Provide floating and fixed point APIs */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
+    int num_weights, png_const_doublep filter_weights,
+    png_const_doublep filter_costs)
+{
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(heuristic_method)
+   PNG_UNUSED(num_weights)
+   PNG_UNUSED(filter_weights)
+   PNG_UNUSED(filter_costs)
+}
+#endif /* FLOATING_POINT */
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
+    int num_weights, png_const_fixed_point_p filter_weights,
+    png_const_fixed_point_p filter_costs)
+{
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(heuristic_method)
+   PNG_UNUSED(num_weights)
+   PNG_UNUSED(filter_weights)
+   PNG_UNUSED(filter_costs)
+}
+#endif /* FIXED_POINT */
+#endif /* WRITE_WEIGHTED_FILTER */
+
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+void PNGAPI
+png_set_compression_level(png_structrp png_ptr, int level)
+{
+   png_debug(1, "in png_set_compression_level");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_level = level;
+}
+
+void PNGAPI
+png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
+{
+   png_debug(1, "in png_set_compression_mem_level");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_mem_level = mem_level;
+}
+
+void PNGAPI
+png_set_compression_strategy(png_structrp png_ptr, int strategy)
+{
+   png_debug(1, "in png_set_compression_strategy");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* The flag setting here prevents the libpng dynamic selection of strategy.
+    */
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
+   png_ptr->zlib_strategy = strategy;
+}
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+void PNGAPI
+png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
+{
+   png_debug(1, "in png_set_compression_window_bits");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* Prior to 1.6.0 this would warn but then set the window_bits value. This
+    * meant that negative window bits values could be selected that would cause
+    * libpng to write a non-standard PNG file with raw deflate or gzip
+    * compressed IDAT or ancillary chunks.  Such files can be read and there is
+    * no warning on read, so this seems like a very bad idea.
+    */
+   if (window_bits > 15)
+   {
+      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
+      window_bits = 15;
+   }
+
+   else if (window_bits < 8)
+   {
+      png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
+      window_bits = 8;
+   }
+
+   png_ptr->zlib_window_bits = window_bits;
+}
+
+void PNGAPI
+png_set_compression_method(png_structrp png_ptr, int method)
+{
+   png_debug(1, "in png_set_compression_method");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* This would produce an invalid PNG file if it worked, but it doesn't and
+    * deflate will fault it, so it is harmless to just warn here.
+    */
+   if (method != 8)
+      png_warning(png_ptr, "Only compression method 8 is supported by PNG");
+
+   png_ptr->zlib_method = method;
+}
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+/* The following were added to libpng-1.5.4 */
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+void PNGAPI
+png_set_text_compression_level(png_structrp png_ptr, int level)
+{
+   png_debug(1, "in png_set_text_compression_level");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_text_level = level;
+}
+
+void PNGAPI
+png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
+{
+   png_debug(1, "in png_set_text_compression_mem_level");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_text_mem_level = mem_level;
+}
+
+void PNGAPI
+png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
+{
+   png_debug(1, "in png_set_text_compression_strategy");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->zlib_text_strategy = strategy;
+}
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+void PNGAPI
+png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
+{
+   png_debug(1, "in png_set_text_compression_window_bits");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (window_bits > 15)
+   {
+      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
+      window_bits = 15;
+   }
+
+   else if (window_bits < 8)
+   {
+      png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
+      window_bits = 8;
+   }
+
+   png_ptr->zlib_text_window_bits = window_bits;
+}
+
+void PNGAPI
+png_set_text_compression_method(png_structrp png_ptr, int method)
+{
+   png_debug(1, "in png_set_text_compression_method");
+
+   if (png_ptr == NULL)
+      return;
+
+   if (method != 8)
+      png_warning(png_ptr, "Only compression method 8 is supported by PNG");
+
+   png_ptr->zlib_text_method = method;
+}
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+/* end of API added to libpng-1.5.4 */
+
+void PNGAPI
+png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
+{
+   png_debug(1, "in png_set_write_status_fn");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->write_row_fn = write_row_fn;
+}
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+void PNGAPI
+png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
+    write_user_transform_fn)
+{
+   png_debug(1, "in png_set_write_user_transform_fn");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= PNG_USER_TRANSFORM;
+   png_ptr->write_user_transform_fn = write_user_transform_fn;
+}
+#endif
+
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+void PNGAPI
+png_write_png(png_structrp png_ptr, png_inforp info_ptr,
+    int transforms, voidp params)
+{
+   png_debug(1, "in png_write_png");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
+   {
+      png_app_error(png_ptr, "no rows for png_write_image to write");
+      return;
+   }
+
+   /* Write the file header information. */
+   png_write_info(png_ptr, info_ptr);
+
+   /* ------ these transformations don't touch the info structure ------- */
+
+   /* Invert monochrome pixels */
+   if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+      png_set_invert_mono(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
+#endif
+
+   /* Shift the pixels up to a legal bit depth and fill in
+    * as appropriate to correctly scale the image.
+    */
+   if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+      if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+         png_set_shift(png_ptr, &info_ptr->sig_bit);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
+#endif
+
+   /* Pack pixels into bytes */
+   if ((transforms & PNG_TRANSFORM_PACKING) != 0)
+#ifdef PNG_WRITE_PACK_SUPPORTED
+      png_set_packing(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
+#endif
+
+   /* Swap location of alpha bytes from ARGB to RGBA */
+   if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+      png_set_swap_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
+#endif
+
+   /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
+    * RGB, note that the code expects the input color type to be G or RGB; no
+    * alpha channel.
+    */
+   if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
+       PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
+   {
+#ifdef PNG_WRITE_FILLER_SUPPORTED
+      if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
+      {
+         if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+            png_app_error(png_ptr,
+                "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
+
+         /* Continue if ignored - this is the pre-1.6.10 behavior */
+         png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
+      }
+
+      else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+         png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
+#endif
+   }
+
+   /* Flip BGR pixels to RGB */
+   if ((transforms & PNG_TRANSFORM_BGR) != 0)
+#ifdef PNG_WRITE_BGR_SUPPORTED
+      png_set_bgr(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
+#endif
+
+   /* Swap bytes of 16-bit files to most significant byte first */
+   if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
+#ifdef PNG_WRITE_SWAP_SUPPORTED
+      png_set_swap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
+#endif
+
+   /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
+   if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+      png_set_packswap(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
+#endif
+
+   /* Invert the alpha channel from opacity to transparency */
+   if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+      png_set_invert_alpha(png_ptr);
+#else
+      png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
+#endif
+
+   /* ----------------------- end of transformations ------------------- */
+
+   /* Write the bits */
+   png_write_image(png_ptr, info_ptr->row_pointers);
+
+   /* It is REQUIRED to call this to finish writing the rest of the file */
+   png_write_end(png_ptr, info_ptr);
+
+   PNG_UNUSED(params)
+}
+#endif
+
+
+#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+/* Initialize the write structure - general purpose utility. */
+static int
+png_image_write_init(png_imagep image)
+{
+   png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
+       png_safe_error, png_safe_warning);
+
+   if (png_ptr != NULL)
+   {
+      png_infop info_ptr = png_create_info_struct(png_ptr);
+
+      if (info_ptr != NULL)
+      {
+         png_controlp control = png_voidcast(png_controlp,
+             png_malloc_warn(png_ptr, (sizeof *control)));
+
+         if (control != NULL)
+         {
+            memset(control, 0, (sizeof *control));
+
+            control->png_ptr = png_ptr;
+            control->info_ptr = info_ptr;
+            control->for_write = 1;
+
+            image->opaque = control;
+            return 1;
+         }
+
+         /* Error clean up */
+         png_destroy_info_struct(png_ptr, &info_ptr);
+      }
+
+      png_destroy_write_struct(&png_ptr, NULL);
+   }
+
+   return png_image_error(image, "png_image_write_: out of memory");
+}
+
+/* Arguments to png_image_write_main: */
+typedef struct
+{
+   /* Arguments: */
+   png_imagep      image;
+   png_const_voidp buffer;
+   png_int_32      row_stride;
+   png_const_voidp colormap;
+   int             convert_to_8bit;
+   /* Local variables: */
+   png_const_voidp first_row;
+   ptrdiff_t       row_bytes;
+   png_voidp       local_row;
+   /* Byte count for memory writing */
+   png_bytep        memory;
+   png_alloc_size_t memory_bytes; /* not used for STDIO */
+   png_alloc_size_t output_bytes; /* running total */
+} png_image_write_control;
+
+/* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
+ * do any necessary byte swapping.  The component order is defined by the
+ * png_image format value.
+ */
+static int
+png_write_image_16bit(png_voidp argument)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+
+   png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
+       display->first_row);
+   png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
+   png_uint_16p row_end;
+   unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
+       3 : 1;
+   int aindex = 0;
+   png_uint_32 y = image->height;
+
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+   {
+#   ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+      if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+      {
+         aindex = -1;
+         ++input_row; /* To point to the first component */
+         ++output_row;
+      }
+         else
+            aindex = (int)channels;
+#     else
+         aindex = (int)channels;
+#     endif
+   }
+
+   else
+      png_error(png_ptr, "png_write_image: internal call error");
+
+   /* Work out the output row end and count over this, note that the increment
+    * above to 'row' means that row_end can actually be beyond the end of the
+    * row; this is correct.
+    */
+   row_end = output_row + image->width * (channels+1);
+
+   for (; y > 0; --y)
+   {
+      png_const_uint_16p in_ptr = input_row;
+      png_uint_16p out_ptr = output_row;
+
+      while (out_ptr < row_end)
+      {
+         png_uint_16 alpha = in_ptr[aindex];
+         png_uint_32 reciprocal = 0;
+         int c;
+
+         out_ptr[aindex] = alpha;
+
+         /* Calculate a reciprocal.  The correct calculation is simply
+          * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
+          * allows correct rounding by adding .5 before the shift.  'reciprocal'
+          * is only initialized when required.
+          */
+         if (alpha > 0 && alpha < 65535)
+            reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
+
+         c = (int)channels;
+         do /* always at least one channel */
+         {
+            png_uint_16 component = *in_ptr++;
+
+            /* The following gives 65535 for an alpha of 0, which is fine,
+             * otherwise if 0/0 is represented as some other value there is more
+             * likely to be a discontinuity which will probably damage
+             * compression when moving from a fully transparent area to a
+             * nearly transparent one.  (The assumption here is that opaque
+             * areas tend not to be 0 intensity.)
+             */
+            if (component >= alpha)
+               component = 65535;
+
+            /* component<alpha, so component/alpha is less than one and
+             * component*reciprocal is less than 2^31.
+             */
+            else if (component > 0 && alpha < 65535)
+            {
+               png_uint_32 calc = component * reciprocal;
+               calc += 16384; /* round to nearest */
+               component = (png_uint_16)(calc >> 15);
+            }
+
+            *out_ptr++ = component;
+         }
+         while (--c > 0);
+
+         /* Skip to next component (skip the intervening alpha channel) */
+         ++in_ptr;
+         ++out_ptr;
+      }
+
+      png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
+      input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
+   }
+
+   return 1;
+}
+
+/* Given 16-bit input (1 to 4 channels) write 8-bit output.  If an alpha channel
+ * is present it must be removed from the components, the components are then
+ * written in sRGB encoding.  No components are added or removed.
+ *
+ * Calculate an alpha reciprocal to reverse pre-multiplication.  As above the
+ * calculation can be done to 15 bits of accuracy; however, the output needs to
+ * be scaled in the range 0..255*65535, so include that scaling here.
+ */
+#   define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha))
+
+static png_byte
+png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
+    png_uint_32 reciprocal/*from the above macro*/)
+{
+   /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
+    * is represented as some other value there is more likely to be a
+    * discontinuity which will probably damage compression when moving from a
+    * fully transparent area to a nearly transparent one.  (The assumption here
+    * is that opaque areas tend not to be 0 intensity.)
+    *
+    * There is a rounding problem here; if alpha is less than 128 it will end up
+    * as 0 when scaled to 8 bits.  To avoid introducing spurious colors into the
+    * output change for this too.
+    */
+   if (component >= alpha || alpha < 128)
+      return 255;
+
+   /* component<alpha, so component/alpha is less than one and
+    * component*reciprocal is less than 2^31.
+    */
+   else if (component > 0)
+   {
+      /* The test is that alpha/257 (rounded) is less than 255, the first value
+       * that becomes 255 is 65407.
+       * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
+       * be exact!)  [Could also test reciprocal != 0]
+       */
+      if (alpha < 65407)
+      {
+         component *= reciprocal;
+         component += 64; /* round to nearest */
+         component >>= 7;
+      }
+
+      else
+         component *= 255;
+
+      /* Convert the component to sRGB. */
+      return (png_byte)PNG_sRGB_FROM_LINEAR(component);
+   }
+
+   else
+      return 0;
+}
+
+static int
+png_write_image_8bit(png_voidp argument)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+
+   png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
+       display->first_row);
+   png_bytep output_row = png_voidcast(png_bytep, display->local_row);
+   png_uint_32 y = image->height;
+   unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
+       3 : 1;
+
+   if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+   {
+      png_bytep row_end;
+      int aindex;
+
+#   ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+      if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+      {
+         aindex = -1;
+         ++input_row; /* To point to the first component */
+         ++output_row;
+      }
+
+      else
+#   endif
+      aindex = (int)channels;
+
+      /* Use row_end in place of a loop counter: */
+      row_end = output_row + image->width * (channels+1);
+
+      for (; y > 0; --y)
+      {
+         png_const_uint_16p in_ptr = input_row;
+         png_bytep out_ptr = output_row;
+
+         while (out_ptr < row_end)
+         {
+            png_uint_16 alpha = in_ptr[aindex];
+            png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
+            png_uint_32 reciprocal = 0;
+            int c;
+
+            /* Scale and write the alpha channel. */
+            out_ptr[aindex] = alphabyte;
+
+            if (alphabyte > 0 && alphabyte < 255)
+               reciprocal = UNP_RECIPROCAL(alpha);
+
+            c = (int)channels;
+            do /* always at least one channel */
+               *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
+            while (--c > 0);
+
+            /* Skip to next component (skip the intervening alpha channel) */
+            ++in_ptr;
+            ++out_ptr;
+         } /* while out_ptr < row_end */
+
+         png_write_row(png_ptr, png_voidcast(png_const_bytep,
+             display->local_row));
+         input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
+      } /* while y */
+   }
+
+   else
+   {
+      /* No alpha channel, so the row_end really is the end of the row and it
+       * is sufficient to loop over the components one by one.
+       */
+      png_bytep row_end = output_row + image->width * channels;
+
+      for (; y > 0; --y)
+      {
+         png_const_uint_16p in_ptr = input_row;
+         png_bytep out_ptr = output_row;
+
+         while (out_ptr < row_end)
+         {
+            png_uint_32 component = *in_ptr++;
+
+            component *= 255;
+            *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
+         }
+
+         png_write_row(png_ptr, output_row);
+         input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
+      }
+   }
+
+   return 1;
+}
+
+static void
+png_image_set_PLTE(png_image_write_control *display)
+{
+   png_imagep image = display->image;
+   const void *cmap = display->colormap;
+   int entries = image->colormap_entries > 256 ? 256 :
+       (int)image->colormap_entries;
+
+   /* NOTE: the caller must check for cmap != NULL and entries != 0 */
+   png_uint_32 format = image->format;
+   unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
+
+#   if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
+      defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
+      int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
+          (format & PNG_FORMAT_FLAG_ALPHA) != 0;
+#   else
+#     define afirst 0
+#   endif
+
+#   ifdef PNG_FORMAT_BGR_SUPPORTED
+      int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
+#   else
+#     define bgr 0
+#   endif
+
+   int i, num_trans;
+   png_color palette[256];
+   png_byte tRNS[256];
+
+   memset(tRNS, 255, (sizeof tRNS));
+   memset(palette, 0, (sizeof palette));
+
+   for (i=num_trans=0; i<entries; ++i)
+   {
+      /* This gets automatically converted to sRGB with reversal of the
+       * pre-multiplication if the color-map has an alpha channel.
+       */
+      if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
+      {
+         png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
+
+         entry += (unsigned int)i * channels;
+
+         if ((channels & 1) != 0) /* no alpha */
+         {
+            if (channels >= 3) /* RGB */
+            {
+               palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
+                   entry[(2 ^ bgr)]);
+               palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
+                   entry[1]);
+               palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
+                   entry[bgr]);
+            }
+
+            else /* Gray */
+               palette[i].blue = palette[i].red = palette[i].green =
+                  (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
+         }
+
+         else /* alpha */
+         {
+            png_uint_16 alpha = entry[afirst ? 0 : channels-1];
+            png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
+            png_uint_32 reciprocal = 0;
+
+            /* Calculate a reciprocal, as in the png_write_image_8bit code above
+             * this is designed to produce a value scaled to 255*65535 when
+             * divided by 128 (i.e. asr 7).
+             */
+            if (alphabyte > 0 && alphabyte < 255)
+               reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
+
+            tRNS[i] = alphabyte;
+            if (alphabyte < 255)
+               num_trans = i+1;
+
+            if (channels >= 3) /* RGB */
+            {
+               palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
+                   alpha, reciprocal);
+               palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
+                   reciprocal);
+               palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
+                   reciprocal);
+            }
+
+            else /* gray */
+               palette[i].blue = palette[i].red = palette[i].green =
+                   png_unpremultiply(entry[afirst], alpha, reciprocal);
+         }
+      }
+
+      else /* Color-map has sRGB values */
+      {
+         png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
+
+         entry += (unsigned int)i * channels;
+
+         switch (channels)
+         {
+            case 4:
+               tRNS[i] = entry[afirst ? 0 : 3];
+               if (tRNS[i] < 255)
+                  num_trans = i+1;
+               /* FALLTHROUGH */
+            case 3:
+               palette[i].blue = entry[afirst + (2 ^ bgr)];
+               palette[i].green = entry[afirst + 1];
+               palette[i].red = entry[afirst + bgr];
+               break;
+
+            case 2:
+               tRNS[i] = entry[1 ^ afirst];
+               if (tRNS[i] < 255)
+                  num_trans = i+1;
+               /* FALLTHROUGH */
+            case 1:
+               palette[i].blue = palette[i].red = palette[i].green =
+                  entry[afirst];
+               break;
+
+            default:
+               break;
+         }
+      }
+   }
+
+#   ifdef afirst
+#     undef afirst
+#   endif
+#   ifdef bgr
+#     undef bgr
+#   endif
+
+   png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
+       entries);
+
+   if (num_trans > 0)
+      png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
+          num_trans, NULL);
+
+   image->colormap_entries = (png_uint_32)entries;
+}
+
+static int
+png_image_write_main(png_voidp argument)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       argument);
+   png_imagep image = display->image;
+   png_structrp png_ptr = image->opaque->png_ptr;
+   png_inforp info_ptr = image->opaque->info_ptr;
+   png_uint_32 format = image->format;
+
+   /* The following four ints are actually booleans */
+   int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
+   int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
+   int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
+   int write_16bit = linear && (display->convert_to_8bit == 0);
+
+#   ifdef PNG_BENIGN_ERRORS_SUPPORTED
+      /* Make sure we error out on any bad situation */
+      png_set_benign_errors(png_ptr, 0/*error*/);
+#   endif
+
+   /* Default the 'row_stride' parameter if required, also check the row stride
+    * and total image size to ensure that they are within the system limits.
+    */
+   {
+      unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
+
+      if (image->width <= 0x7fffffffU/channels) /* no overflow */
+      {
+         png_uint_32 check;
+         png_uint_32 png_row_stride = image->width * channels;
+
+         if (display->row_stride == 0)
+            display->row_stride = (png_int_32)/*SAFE*/png_row_stride;
+
+         if (display->row_stride < 0)
+            check = (png_uint_32)(-display->row_stride);
+
+         else
+            check = (png_uint_32)display->row_stride;
+
+         if (check >= png_row_stride)
+         {
+            /* Now check for overflow of the image buffer calculation; this
+             * limits the whole image size to 32 bits for API compatibility with
+             * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
+             */
+            if (image->height > 0xffffffffU/png_row_stride)
+               png_error(image->opaque->png_ptr, "memory image too large");
+         }
+
+         else
+            png_error(image->opaque->png_ptr, "supplied row stride too small");
+      }
+
+      else
+         png_error(image->opaque->png_ptr, "image row stride too large");
+   }
+
+   /* Set the required transforms then write the rows in the correct order. */
+   if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+   {
+      if (display->colormap != NULL && image->colormap_entries > 0)
+      {
+         png_uint_32 entries = image->colormap_entries;
+
+         png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
+             entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
+             PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
+             PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+         png_image_set_PLTE(display);
+      }
+
+      else
+         png_error(image->opaque->png_ptr,
+             "no color-map for color-mapped image");
+   }
+
+   else
+      png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
+          write_16bit ? 16 : 8,
+          ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
+          ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
+          PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+   /* Counter-intuitively the data transformations must be called *after*
+    * png_write_info, not before as in the read code, but the 'set' functions
+    * must still be called before.  Just set the color space information, never
+    * write an interlaced image.
+    */
+
+   if (write_16bit != 0)
+   {
+      /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
+      png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
+
+      if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
+         png_set_cHRM_fixed(png_ptr, info_ptr,
+             /* color      x       y */
+             /* white */ 31270, 32900,
+             /* red   */ 64000, 33000,
+             /* green */ 30000, 60000,
+             /* blue  */ 15000,  6000
+         );
+   }
+
+   else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
+      png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
+
+   /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
+    * space must still be gamma encoded.
+    */
+   else
+      png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
+
+   /* Write the file header. */
+   png_write_info(png_ptr, info_ptr);
+
+   /* Now set up the data transformations (*after* the header is written),
+    * remove the handled transformations from the 'format' flags for checking.
+    *
+    * First check for a little endian system if writing 16-bit files.
+    */
+   if (write_16bit != 0)
+   {
+      png_uint_16 le = 0x0001;
+
+      if ((*(png_const_bytep) & le) != 0)
+         png_set_swap(png_ptr);
+   }
+
+#   ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
+      if ((format & PNG_FORMAT_FLAG_BGR) != 0)
+      {
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
+            png_set_bgr(png_ptr);
+         format &= ~PNG_FORMAT_FLAG_BGR;
+      }
+#   endif
+
+#   ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+      if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+      {
+         if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
+            png_set_swap_alpha(png_ptr);
+         format &= ~PNG_FORMAT_FLAG_AFIRST;
+      }
+#   endif
+
+   /* If there are 16 or fewer color-map entries we wrote a lower bit depth
+    * above, but the application data is still byte packed.
+    */
+   if (colormap != 0 && image->colormap_entries <= 16)
+      png_set_packing(png_ptr);
+
+   /* That should have handled all (both) the transforms. */
+   if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
+         PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
+      png_error(png_ptr, "png_write_image: unsupported transformation");
+
+   {
+      png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
+      ptrdiff_t row_bytes = display->row_stride;
+
+      if (linear != 0)
+         row_bytes *= (sizeof (png_uint_16));
+
+      if (row_bytes < 0)
+         row += (image->height-1) * (-row_bytes);
+
+      display->first_row = row;
+      display->row_bytes = row_bytes;
+   }
+
+   /* Apply 'fast' options if the flag is set. */
+   if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
+   {
+      png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
+      /* NOTE: determined by experiment using pngstest, this reflects some
+       * balance between the time to write the image once and the time to read
+       * it about 50 times.  The speed-up in pngstest was about 10-20% of the
+       * total (user) time on a heavily loaded system.
+       */
+#   ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+      png_set_compression_level(png_ptr, 3);
+#   endif
+   }
+
+   /* Check for the cases that currently require a pre-transform on the row
+    * before it is written.  This only applies when the input is 16-bit and
+    * either there is an alpha channel or it is converted to 8-bit.
+    */
+   if ((linear != 0 && alpha != 0 ) ||
+       (colormap == 0 && display->convert_to_8bit != 0))
+   {
+      png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
+          png_get_rowbytes(png_ptr, info_ptr)));
+      int result;
+
+      display->local_row = row;
+      if (write_16bit != 0)
+         result = png_safe_execute(image, png_write_image_16bit, display);
+      else
+         result = png_safe_execute(image, png_write_image_8bit, display);
+      display->local_row = NULL;
+
+      png_free(png_ptr, row);
+
+      /* Skip the 'write_end' on error: */
+      if (result == 0)
+         return 0;
+   }
+
+   /* Otherwise this is the case where the input is in a format currently
+    * supported by the rest of the libpng write code; call it directly.
+    */
+   else
+   {
+      png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
+      ptrdiff_t row_bytes = display->row_bytes;
+      png_uint_32 y = image->height;
+
+      for (; y > 0; --y)
+      {
+         png_write_row(png_ptr, row);
+         row += row_bytes;
+      }
+   }
+
+   png_write_end(png_ptr, info_ptr);
+   return 1;
+}
+
+
+static void (PNGCBAPI
+image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data, size_t size)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       png_ptr->io_ptr/*backdoor: png_get_io_ptr(png_ptr)*/);
+   png_alloc_size_t ob = display->output_bytes;
+
+   /* Check for overflow; this should never happen: */
+   if (size <= ((png_alloc_size_t)-1) - ob)
+   {
+      /* I don't think libpng ever does this, but just in case: */
+      if (size > 0)
+      {
+         if (display->memory_bytes >= ob+size) /* writing */
+            memcpy(display->memory+ob, data, size);
+
+         /* Always update the size: */
+         display->output_bytes = ob+size;
+      }
+   }
+
+   else
+      png_error(png_ptr, "png_image_write_to_memory: PNG too big");
+}
+
+static void (PNGCBAPI
+image_memory_flush)(png_structp png_ptr)
+{
+   PNG_UNUSED(png_ptr)
+}
+
+static int
+png_image_write_memory(png_voidp argument)
+{
+   png_image_write_control *display = png_voidcast(png_image_write_control*,
+       argument);
+
+   /* The rest of the memory-specific init and write_main in an error protected
+    * environment.  This case needs to use callbacks for the write operations
+    * since libpng has no built in support for writing to memory.
+    */
+   png_set_write_fn(display->image->opaque->png_ptr, display/*io_ptr*/,
+       image_memory_write, image_memory_flush);
+
+   return png_image_write_main(display);
+}
+
+int PNGAPI
+png_image_write_to_memory(png_imagep image, void *memory,
+    png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8bit,
+    const void *buffer, png_int_32 row_stride, const void *colormap)
+{
+   /* Write the image to the given buffer, or count the bytes if it is NULL */
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (memory_bytes != NULL && buffer != NULL)
+      {
+         /* This is to give the caller an easier error detection in the NULL
+          * case and guard against uninitialized variable problems:
+          */
+         if (memory == NULL)
+            *memory_bytes = 0;
+
+         if (png_image_write_init(image) != 0)
+         {
+            png_image_write_control display;
+            int result;
+
+            memset(&display, 0, (sizeof display));
+            display.image = image;
+            display.buffer = buffer;
+            display.row_stride = row_stride;
+            display.colormap = colormap;
+            display.convert_to_8bit = convert_to_8bit;
+            display.memory = png_voidcast(png_bytep, memory);
+            display.memory_bytes = *memory_bytes;
+            display.output_bytes = 0;
+
+            result = png_safe_execute(image, png_image_write_memory, &display);
+            png_image_free(image);
+
+            /* write_memory returns true even if we ran out of buffer. */
+            if (result)
+            {
+               /* On out-of-buffer this function returns '0' but still updates
+                * memory_bytes:
+                */
+               if (memory != NULL && display.output_bytes > *memory_bytes)
+                  result = 0;
+
+               *memory_bytes = display.output_bytes;
+            }
+
+            return result;
+         }
+
+         else
+            return 0;
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_write_to_memory: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
+
+   else
+      return 0;
+}
+
+#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+int PNGAPI
+png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
+    const void *buffer, png_int_32 row_stride, const void *colormap)
+{
+   /* Write the image to the given (FILE*). */
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (file != NULL && buffer != NULL)
+      {
+         if (png_image_write_init(image) != 0)
+         {
+            png_image_write_control display;
+            int result;
+
+            /* This is slightly evil, but png_init_io doesn't do anything other
+             * than this and we haven't changed the standard IO functions so
+             * this saves a 'safe' function.
+             */
+            image->opaque->png_ptr->io_ptr = file;
+
+            memset(&display, 0, (sizeof display));
+            display.image = image;
+            display.buffer = buffer;
+            display.row_stride = row_stride;
+            display.colormap = colormap;
+            display.convert_to_8bit = convert_to_8bit;
+
+            result = png_safe_execute(image, png_image_write_main, &display);
+            png_image_free(image);
+            return result;
+         }
+
+         else
+            return 0;
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_write_to_stdio: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
+
+   else
+      return 0;
+}
+
+int PNGAPI
+png_image_write_to_file(png_imagep image, const char *file_name,
+    int convert_to_8bit, const void *buffer, png_int_32 row_stride,
+    const void *colormap)
+{
+   /* Write the image to the named file. */
+   if (image != NULL && image->version == PNG_IMAGE_VERSION)
+   {
+      if (file_name != NULL && buffer != NULL)
+      {
+         FILE *fp = fopen(file_name, "wb");
+
+         if (fp != NULL)
+         {
+            if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
+                row_stride, colormap) != 0)
+            {
+               int error; /* from fflush/fclose */
+
+               /* Make sure the file is flushed correctly. */
+               if (fflush(fp) == 0 && ferror(fp) == 0)
+               {
+                  if (fclose(fp) == 0)
+                     return 1;
+
+                  error = errno; /* from fclose */
+               }
+
+               else
+               {
+                  error = errno; /* from fflush or ferror */
+                  (void)fclose(fp);
+               }
+
+               (void)remove(file_name);
+               /* The image has already been cleaned up; this is just used to
+                * set the error (because the original write succeeded).
+                */
+               return png_image_error(image, strerror(error));
+            }
+
+            else
+            {
+               /* Clean up: just the opened file. */
+               (void)fclose(fp);
+               (void)remove(file_name);
+               return 0;
+            }
+         }
+
+         else
+            return png_image_error(image, strerror(errno));
+      }
+
+      else
+         return png_image_error(image,
+             "png_image_write_to_file: invalid argument");
+   }
+
+   else if (image != NULL)
+      return png_image_error(image,
+          "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
+
+   else
+      return 0;
+}
+#endif /* SIMPLIFIED_WRITE_STDIO */
+#endif /* SIMPLIFIED_WRITE */
+#endif /* WRITE */
Index: /trunk/src/libs/libpng-1.6.45/pngwtran.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngwtran.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngwtran.c	(revision 107811)
@@ -0,0 +1,575 @@
+
+/* pngwtran.c - transforms the data in a row for PNG writers
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+
+#ifdef PNG_WRITE_PACK_SUPPORTED
+/* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
+ * row_info bit depth should be 8 (one pixel per byte).  The channels
+ * should be 1 (this only happens on grayscale and paletted images).
+ */
+static void
+png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
+{
+   png_debug(1, "in png_do_pack");
+
+   if (row_info->bit_depth == 8 &&
+      row_info->channels == 1)
+   {
+      switch ((int)bit_depth)
+      {
+         case 1:
+         {
+            png_bytep sp, dp;
+            int mask, v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            mask = 0x80;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               if (*sp != 0)
+                  v |= mask;
+
+               sp++;
+
+               if (mask > 1)
+                  mask >>= 1;
+
+               else
+               {
+                  mask = 0x80;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+            }
+
+            if (mask != 0x80)
+               *dp = (png_byte)v;
+
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp, dp;
+            unsigned int shift;
+            int v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            shift = 6;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte value;
+
+               value = (png_byte)(*sp & 0x03);
+               v |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 6;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+
+               else
+                  shift -= 2;
+
+               sp++;
+            }
+
+            if (shift != 6)
+               *dp = (png_byte)v;
+
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp, dp;
+            unsigned int shift;
+            int v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            shift = 4;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte value;
+
+               value = (png_byte)(*sp & 0x0f);
+               v |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 4;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+
+               else
+                  shift -= 4;
+
+               sp++;
+            }
+
+            if (shift != 4)
+               *dp = (png_byte)v;
+
+            break;
+         }
+
+         default:
+            break;
+      }
+
+      row_info->bit_depth = (png_byte)bit_depth;
+      row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+          row_info->width);
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+/* Shift pixel values to take advantage of whole range.  Pass the
+ * true number of bits in bit_depth.  The row should be packed
+ * according to row_info->bit_depth.  Thus, if you had a row of
+ * bit depth 4, but the pixels only had values from 0 to 7, you
+ * would pass 3 as bit_depth, and this routine would translate the
+ * data to 0 to 15.
+ */
+static void
+png_do_shift(png_row_infop row_info, png_bytep row,
+    png_const_color_8p bit_depth)
+{
+   png_debug(1, "in png_do_shift");
+
+   if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      int shift_start[4], shift_dec[4];
+      unsigned int channels = 0;
+
+      if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->red;
+         shift_dec[channels] = bit_depth->red;
+         channels++;
+
+         shift_start[channels] = row_info->bit_depth - bit_depth->green;
+         shift_dec[channels] = bit_depth->green;
+         channels++;
+
+         shift_start[channels] = row_info->bit_depth - bit_depth->blue;
+         shift_dec[channels] = bit_depth->blue;
+         channels++;
+      }
+
+      else
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->gray;
+         shift_dec[channels] = bit_depth->gray;
+         channels++;
+      }
+
+      if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
+         shift_dec[channels] = bit_depth->alpha;
+         channels++;
+      }
+
+      /* With low row depths, could only be grayscale, so one channel */
+      if (row_info->bit_depth < 8)
+      {
+         png_bytep bp = row;
+         size_t i;
+         unsigned int mask;
+         size_t row_bytes = row_info->rowbytes;
+
+         if (bit_depth->gray == 1 && row_info->bit_depth == 2)
+            mask = 0x55;
+
+         else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
+            mask = 0x11;
+
+         else
+            mask = 0xff;
+
+         for (i = 0; i < row_bytes; i++, bp++)
+         {
+            int j;
+            unsigned int v, out;
+
+            v = *bp;
+            out = 0;
+
+            for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
+            {
+               if (j > 0)
+                  out |= v << j;
+
+               else
+                  out |= (v >> (-j)) & mask;
+            }
+
+            *bp = (png_byte)(out & 0xff);
+         }
+      }
+
+      else if (row_info->bit_depth == 8)
+      {
+         png_bytep bp = row;
+         png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
+
+         for (i = 0; i < istop; i++, bp++)
+         {
+            unsigned int c = i%channels;
+            int j;
+            unsigned int v, out;
+
+            v = *bp;
+            out = 0;
+
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+            {
+               if (j > 0)
+                  out |= v << j;
+
+               else
+                  out |= v >> (-j);
+            }
+
+            *bp = (png_byte)(out & 0xff);
+         }
+      }
+
+      else
+      {
+         png_bytep bp;
+         png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
+
+         for (bp = row, i = 0; i < istop; i++)
+         {
+            unsigned int c = i%channels;
+            int j;
+            unsigned int value, v;
+
+            v = png_get_uint_16(bp);
+            value = 0;
+
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+            {
+               if (j > 0)
+                  value |= v << j;
+
+               else
+                  value |= v >> (-j);
+            }
+            *bp++ = (png_byte)((value >> 8) & 0xff);
+            *bp++ = (png_byte)(value & 0xff);
+         }
+      }
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+static void
+png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_swap_alpha");
+
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This converts from ARGB to RGBA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save;
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This converts from AARRGGBB to RRGGBBAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save[2];
+               save[0] = *(sp++);
+               save[1] = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save[0];
+               *(dp++) = save[1];
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This converts from AG to GA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save;
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This converts from AAGG to GGAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save[2];
+               save[0] = *(sp++);
+               save[1] = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save[0];
+               *(dp++) = save[1];
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+static void
+png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_invert_alpha");
+
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This inverts the alpha channel in RGBA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* Does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=3; dp = sp;
+               *dp = (png_byte)(255 - *(sp++));
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This inverts the alpha channel in RRGGBBAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* Does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=6; dp = sp;
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *dp     = (png_byte)(255 - *(sp++));
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This inverts the alpha channel in GA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               *(dp++) = *(sp++);
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         else
+         {
+            /* This inverts the alpha channel in GGAA */
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* Does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=2; dp = sp;
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *dp     = (png_byte)(255 - *(sp++));
+            }
+         }
+#endif /* WRITE_16BIT */
+      }
+   }
+}
+#endif
+
+/* Transform the data according to the user's wishes.  The order of
+ * transformations is significant.
+ */
+void /* PRIVATE */
+png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
+{
+   png_debug(1, "in png_do_write_transformations");
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+   if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+      if (png_ptr->write_user_transform_fn != NULL)
+         (*(png_ptr->write_user_transform_fn)) /* User write transform
+                                                 function */
+             (png_ptr,  /* png_ptr */
+             row_info,  /* row_info: */
+                /*  png_uint_32 width;       width of row */
+                /*  size_t rowbytes;         number of bytes in row */
+                /*  png_byte color_type;     color type of pixels */
+                /*  png_byte bit_depth;      bit depth of samples */
+                /*  png_byte channels;       number of channels (1-4) */
+                /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
+             png_ptr->row_buf + 1);      /* start of pixel data for row */
+#endif
+
+#ifdef PNG_WRITE_FILLER_SUPPORTED
+   if ((png_ptr->transformations & PNG_FILLER) != 0)
+      png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+          !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
+#endif
+
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+      png_do_packswap(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_PACK_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACK) != 0)
+      png_do_pack(row_info, png_ptr->row_buf + 1,
+          (png_uint_32)png_ptr->bit_depth);
+#endif
+
+#ifdef PNG_WRITE_SWAP_SUPPORTED
+#  ifdef PNG_16BIT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+      png_do_swap(row_info, png_ptr->row_buf + 1);
+#  endif
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+   if ((png_ptr->transformations & PNG_SHIFT) != 0)
+      png_do_shift(row_info, png_ptr->row_buf + 1,
+           &(png_ptr->shift));
+#endif
+
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
+      png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+   if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+      png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_BGR_SUPPORTED
+   if ((png_ptr->transformations & PNG_BGR) != 0)
+      png_do_bgr(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+   if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+      png_do_invert(row_info, png_ptr->row_buf + 1);
+#endif
+}
+#endif /* WRITE_TRANSFORMS */
+#endif /* WRITE */
Index: /trunk/src/libs/libpng-1.6.45/pngwutil.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/pngwutil.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/pngwutil.c	(revision 107811)
@@ -0,0 +1,2781 @@
+
+/* pngwutil.c - utilities to write a PNG file
+ *
+ * Copyright (c) 2018-2024 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+/* Place a 32-bit number into a buffer in PNG byte order.  We work
+ * with unsigned numbers for convenience, although one supported
+ * ancillary chunk uses signed (two's complement) numbers.
+ */
+void PNGAPI
+png_save_uint_32(png_bytep buf, png_uint_32 i)
+{
+   buf[0] = (png_byte)((i >> 24) & 0xffU);
+   buf[1] = (png_byte)((i >> 16) & 0xffU);
+   buf[2] = (png_byte)((i >>  8) & 0xffU);
+   buf[3] = (png_byte)( i        & 0xffU);
+}
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+void PNGAPI
+png_save_uint_16(png_bytep buf, unsigned int i)
+{
+   buf[0] = (png_byte)((i >> 8) & 0xffU);
+   buf[1] = (png_byte)( i       & 0xffU);
+}
+#endif
+
+/* Simple function to write the signature.  If we have already written
+ * the magic bytes of the signature, or more likely, the PNG stream is
+ * being embedded into another stream and doesn't need its own signature,
+ * we should call png_set_sig_bytes() to tell libpng how many of the
+ * bytes have already been written.
+ */
+void PNGAPI
+png_write_sig(png_structrp png_ptr)
+{
+   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   /* Inform the I/O callback that the signature is being written */
+   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;
+#endif
+
+   /* Write the rest of the 8 byte signature */
+   png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
+       (size_t)(8 - png_ptr->sig_bytes));
+
+   if (png_ptr->sig_bytes < 3)
+      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
+/* Write the start of a PNG chunk.  The type is the chunk type.
+ * The total_length is the sum of the lengths of all the data you will be
+ * passing in png_write_chunk_data().
+ */
+static void
+png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name,
+    png_uint_32 length)
+{
+   png_byte buf[8];
+
+#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
+   PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
+   png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
+#endif
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   /* Inform the I/O callback that the chunk header is being written.
+    * PNG_IO_CHUNK_HDR requires a single I/O call.
+    */
+   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;
+#endif
+
+   /* Write the length and the chunk name */
+   png_save_uint_32(buf, length);
+   png_save_uint_32(buf + 4, chunk_name);
+   png_write_data(png_ptr, buf, 8);
+
+   /* Put the chunk name into png_ptr->chunk_name */
+   png_ptr->chunk_name = chunk_name;
+
+   /* Reset the crc and run it over the chunk name */
+   png_reset_crc(png_ptr);
+
+   png_calculate_crc(png_ptr, buf + 4, 4);
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   /* Inform the I/O callback that chunk data will (possibly) be written.
+    * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
+    */
+   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
+#endif
+}
+
+void PNGAPI
+png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string,
+    png_uint_32 length)
+{
+   png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
+}
+
+/* Write the data of a PNG chunk started with png_write_chunk_header().
+ * Note that multiple calls to this function are allowed, and that the
+ * sum of the lengths from these calls *must* add up to the total_length
+ * given to png_write_chunk_header().
+ */
+void PNGAPI
+png_write_chunk_data(png_structrp png_ptr, png_const_bytep data, size_t length)
+{
+   /* Write the data, and run the CRC over it */
+   if (png_ptr == NULL)
+      return;
+
+   if (data != NULL && length > 0)
+   {
+      png_write_data(png_ptr, data, length);
+
+      /* Update the CRC after writing the data,
+       * in case the user I/O routine alters it.
+       */
+      png_calculate_crc(png_ptr, data, length);
+   }
+}
+
+/* Finish a chunk started with png_write_chunk_header(). */
+void PNGAPI
+png_write_chunk_end(png_structrp png_ptr)
+{
+   png_byte buf[4];
+
+   if (png_ptr == NULL) return;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+   /* Inform the I/O callback that the chunk CRC is being written.
+    * PNG_IO_CHUNK_CRC requires a single I/O function call.
+    */
+   png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
+#endif
+
+   /* Write the crc in a single operation */
+   png_save_uint_32(buf, png_ptr->crc);
+
+   png_write_data(png_ptr, buf, 4);
+}
+
+/* Write a PNG chunk all at once.  The type is an array of ASCII characters
+ * representing the chunk name.  The array must be at least 4 bytes in
+ * length, and does not need to be null terminated.  To be safe, pass the
+ * pre-defined chunk names here, and if you need a new one, define it
+ * where the others are defined.  The length is the length of the data.
+ * All the data must be present.  If that is not possible, use the
+ * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
+ * functions instead.
+ */
+static void
+png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
+    png_const_bytep data, size_t length)
+{
+   if (png_ptr == NULL)
+      return;
+
+   /* On 64-bit architectures 'length' may not fit in a png_uint_32. */
+   if (length > PNG_UINT_31_MAX)
+      png_error(png_ptr, "length exceeds PNG maximum");
+
+   png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
+   png_write_chunk_data(png_ptr, data, length);
+   png_write_chunk_end(png_ptr);
+}
+
+/* This is the API that calls the internal function above. */
+void PNGAPI
+png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
+    png_const_bytep data, size_t length)
+{
+   png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
+       length);
+}
+
+/* This is used below to find the size of an image to pass to png_deflate_claim,
+ * so it only needs to be accurate if the size is less than 16384 bytes (the
+ * point at which a lower LZ window size can be used.)
+ */
+static png_alloc_size_t
+png_image_size(png_structrp png_ptr)
+{
+   /* Only return sizes up to the maximum of a png_uint_32; do this by limiting
+    * the width and height used to 15 bits.
+    */
+   png_uint_32 h = png_ptr->height;
+
+   if (png_ptr->rowbytes < 32768 && h < 32768)
+   {
+      if (png_ptr->interlaced != 0)
+      {
+         /* Interlacing makes the image larger because of the replication of
+          * both the filter byte and the padding to a byte boundary.
+          */
+         png_uint_32 w = png_ptr->width;
+         unsigned int pd = png_ptr->pixel_depth;
+         png_alloc_size_t cb_base;
+         int pass;
+
+         for (cb_base=0, pass=0; pass<=6; ++pass)
+         {
+            png_uint_32 pw = PNG_PASS_COLS(w, pass);
+
+            if (pw > 0)
+               cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass);
+         }
+
+         return cb_base;
+      }
+
+      else
+         return (png_ptr->rowbytes+1) * h;
+   }
+
+   else
+      return 0xffffffffU;
+}
+
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+   /* This is the code to hack the first two bytes of the deflate stream (the
+    * deflate header) to correct the windowBits value to match the actual data
+    * size.  Note that the second argument is the *uncompressed* size but the
+    * first argument is the *compressed* data (and it must be deflate
+    * compressed.)
+    */
+static void
+optimize_cmf(png_bytep data, png_alloc_size_t data_size)
+{
+   /* Optimize the CMF field in the zlib stream.  The resultant zlib stream is
+    * still compliant to the stream specification.
+    */
+   if (data_size <= 16384) /* else windowBits must be 15 */
+   {
+      unsigned int z_cmf = data[0];  /* zlib compression method and flags */
+
+      if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
+      {
+         unsigned int z_cinfo;
+         unsigned int half_z_window_size;
+
+         z_cinfo = z_cmf >> 4;
+         half_z_window_size = 1U << (z_cinfo + 7);
+
+         if (data_size <= half_z_window_size) /* else no change */
+         {
+            unsigned int tmp;
+
+            do
+            {
+               half_z_window_size >>= 1;
+               --z_cinfo;
+            }
+            while (z_cinfo > 0 && data_size <= half_z_window_size);
+
+            z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
+
+            data[0] = (png_byte)z_cmf;
+            tmp = data[1] & 0xe0;
+            tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
+            data[1] = (png_byte)tmp;
+         }
+      }
+   }
+}
+#endif /* WRITE_OPTIMIZE_CMF */
+
+/* Initialize the compressor for the appropriate type of compression. */
+static int
+png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
+    png_alloc_size_t data_size)
+{
+   if (png_ptr->zowner != 0)
+   {
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
+      char msg[64];
+
+      PNG_STRING_FROM_CHUNK(msg, owner);
+      msg[4] = ':';
+      msg[5] = ' ';
+      PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner);
+      /* So the message that results is "<chunk> using zstream"; this is an
+       * internal error, but is very useful for debugging.  i18n requirements
+       * are minimal.
+       */
+      (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
+#endif
+#if PNG_RELEASE_BUILD
+         png_warning(png_ptr, msg);
+
+         /* Attempt sane error recovery */
+         if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */
+         {
+            png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT");
+            return Z_STREAM_ERROR;
+         }
+
+         png_ptr->zowner = 0;
+#else
+         png_error(png_ptr, msg);
+#endif
+   }
+
+   {
+      int level = png_ptr->zlib_level;
+      int method = png_ptr->zlib_method;
+      int windowBits = png_ptr->zlib_window_bits;
+      int memLevel = png_ptr->zlib_mem_level;
+      int strategy; /* set below */
+      int ret; /* zlib return code */
+
+      if (owner == png_IDAT)
+      {
+         if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
+            strategy = png_ptr->zlib_strategy;
+
+         else if (png_ptr->do_filter != PNG_FILTER_NONE)
+            strategy = PNG_Z_DEFAULT_STRATEGY;
+
+         else
+            strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY;
+      }
+
+      else
+      {
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+            level = png_ptr->zlib_text_level;
+            method = png_ptr->zlib_text_method;
+            windowBits = png_ptr->zlib_text_window_bits;
+            memLevel = png_ptr->zlib_text_mem_level;
+            strategy = png_ptr->zlib_text_strategy;
+#else
+            /* If customization is not supported the values all come from the
+             * IDAT values except for the strategy, which is fixed to the
+             * default.  (This is the pre-1.6.0 behavior too, although it was
+             * implemented in a very different way.)
+             */
+            strategy = Z_DEFAULT_STRATEGY;
+#endif
+      }
+
+      /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
+       * happening just pass 32768 as the data_size parameter.  Notice that zlib
+       * requires an extra 262 bytes in the window in addition to the data to be
+       * able to see the whole of the data, so if data_size+262 takes us to the
+       * next windowBits size we need to fix up the value later.  (Because even
+       * though deflate needs the extra window, inflate does not!)
+       */
+      if (data_size <= 16384)
+      {
+         /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to
+          * work round a Microsoft Visual C misbehavior which, contrary to C-90,
+          * widens the result of the following shift to 64-bits if (and,
+          * apparently, only if) it is used in a test.
+          */
+         unsigned int half_window_size = 1U << (windowBits-1);
+
+         while (data_size + 262 <= half_window_size)
+         {
+            half_window_size >>= 1;
+            --windowBits;
+         }
+      }
+
+      /* Check against the previous initialized values, if any. */
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
+         (png_ptr->zlib_set_level != level ||
+         png_ptr->zlib_set_method != method ||
+         png_ptr->zlib_set_window_bits != windowBits ||
+         png_ptr->zlib_set_mem_level != memLevel ||
+         png_ptr->zlib_set_strategy != strategy))
+      {
+         if (deflateEnd(&png_ptr->zstream) != Z_OK)
+            png_warning(png_ptr, "deflateEnd failed (ignored)");
+
+         png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED;
+      }
+
+      /* For safety clear out the input and output pointers (currently zlib
+       * doesn't use them on Init, but it might in the future).
+       */
+      png_ptr->zstream.next_in = NULL;
+      png_ptr->zstream.avail_in = 0;
+      png_ptr->zstream.next_out = NULL;
+      png_ptr->zstream.avail_out = 0;
+
+      /* Now initialize if required, setting the new parameters, otherwise just
+       * do a simple reset to the previous parameters.
+       */
+      if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+         ret = deflateReset(&png_ptr->zstream);
+
+      else
+      {
+         ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,
+             memLevel, strategy);
+
+         if (ret == Z_OK)
+            png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
+      }
+
+      /* The return code is from either deflateReset or deflateInit2; they have
+       * pretty much the same set of error codes.
+       */
+      if (ret == Z_OK)
+         png_ptr->zowner = owner;
+
+      else
+         png_zstream_error(png_ptr, ret);
+
+      return ret;
+   }
+}
+
+/* Clean up (or trim) a linked list of compression buffers. */
+void /* PRIVATE */
+png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp)
+{
+   png_compression_bufferp list = *listp;
+
+   if (list != NULL)
+   {
+      *listp = NULL;
+
+      do
+      {
+         png_compression_bufferp next = list->next;
+
+         png_free(png_ptr, list);
+         list = next;
+      }
+      while (list != NULL);
+   }
+}
+
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+/* This pair of functions encapsulates the operation of (a) compressing a
+ * text string, and (b) issuing it later as a series of chunk data writes.
+ * The compression_state structure is shared context for these functions
+ * set up by the caller to allow access to the relevant local variables.
+ *
+ * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size
+ * temporary buffers.  From 1.6.0 it is retained in png_struct so that it will
+ * be correctly freed in the event of a write error (previous implementations
+ * just leaked memory.)
+ */
+typedef struct
+{
+   png_const_bytep      input;        /* The uncompressed input data */
+   png_alloc_size_t     input_len;    /* Its length */
+   png_uint_32          output_len;   /* Final compressed length */
+   png_byte             output[1024]; /* First block of output */
+} compression_state;
+
+static void
+png_text_compress_init(compression_state *comp, png_const_bytep input,
+    png_alloc_size_t input_len)
+{
+   comp->input = input;
+   comp->input_len = input_len;
+   comp->output_len = 0;
+}
+
+/* Compress the data in the compression state input */
+static int
+png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
+    compression_state *comp, png_uint_32 prefix_len)
+{
+   int ret;
+
+   /* To find the length of the output it is necessary to first compress the
+    * input. The result is buffered rather than using the two-pass algorithm
+    * that is used on the inflate side; deflate is assumed to be slower and a
+    * PNG writer is assumed to have more memory available than a PNG reader.
+    *
+    * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an
+    * upper limit on the output size, but it is always bigger than the input
+    * size so it is likely to be more efficient to use this linked-list
+    * approach.
+    */
+   ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len);
+
+   if (ret != Z_OK)
+      return ret;
+
+   /* Set up the compression buffers, we need a loop here to avoid overflowing a
+    * uInt.  Use ZLIB_IO_MAX to limit the input.  The output is always limited
+    * by the output buffer size, so there is no need to check that.  Since this
+    * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits
+    * in size.
+    */
+   {
+      png_compression_bufferp *end = &png_ptr->zbuffer_list;
+      png_alloc_size_t input_len = comp->input_len; /* may be zero! */
+      png_uint_32 output_len;
+
+      /* zlib updates these for us: */
+      png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input);
+      png_ptr->zstream.avail_in = 0; /* Set below */
+      png_ptr->zstream.next_out = comp->output;
+      png_ptr->zstream.avail_out = (sizeof comp->output);
+
+      output_len = png_ptr->zstream.avail_out;
+
+      do
+      {
+         uInt avail_in = ZLIB_IO_MAX;
+
+         if (avail_in > input_len)
+            avail_in = (uInt)input_len;
+
+         input_len -= avail_in;
+
+         png_ptr->zstream.avail_in = avail_in;
+
+         if (png_ptr->zstream.avail_out == 0)
+         {
+            png_compression_buffer *next;
+
+            /* Chunk data is limited to 2^31 bytes in length, so the prefix
+             * length must be counted here.
+             */
+            if (output_len + prefix_len > PNG_UINT_31_MAX)
+            {
+               ret = Z_MEM_ERROR;
+               break;
+            }
+
+            /* Need a new (malloc'ed) buffer, but there may be one present
+             * already.
+             */
+            next = *end;
+            if (next == NULL)
+            {
+               next = png_voidcast(png_compression_bufferp, png_malloc_base
+                  (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
+
+               if (next == NULL)
+               {
+                  ret = Z_MEM_ERROR;
+                  break;
+               }
+
+               /* Link in this buffer (so that it will be freed later) */
+               next->next = NULL;
+               *end = next;
+            }
+
+            png_ptr->zstream.next_out = next->output;
+            png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
+            output_len += png_ptr->zstream.avail_out;
+
+            /* Move 'end' to the next buffer pointer. */
+            end = &next->next;
+         }
+
+         /* Compress the data */
+         ret = deflate(&png_ptr->zstream,
+             input_len > 0 ? Z_NO_FLUSH : Z_FINISH);
+
+         /* Claw back input data that was not consumed (because avail_in is
+          * reset above every time round the loop).
+          */
+         input_len += png_ptr->zstream.avail_in;
+         png_ptr->zstream.avail_in = 0; /* safety */
+      }
+      while (ret == Z_OK);
+
+      /* There may be some space left in the last output buffer. This needs to
+       * be subtracted from output_len.
+       */
+      output_len -= png_ptr->zstream.avail_out;
+      png_ptr->zstream.avail_out = 0; /* safety */
+      comp->output_len = output_len;
+
+      /* Now double check the output length, put in a custom message if it is
+       * too long.  Otherwise ensure the z_stream::msg pointer is set to
+       * something.
+       */
+      if (output_len + prefix_len >= PNG_UINT_31_MAX)
+      {
+         png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long");
+         ret = Z_MEM_ERROR;
+      }
+
+      else
+         png_zstream_error(png_ptr, ret);
+
+      /* Reset zlib for another zTXt/iTXt or image data */
+      png_ptr->zowner = 0;
+
+      /* The only success case is Z_STREAM_END, input_len must be 0; if not this
+       * is an internal error.
+       */
+      if (ret == Z_STREAM_END && input_len == 0)
+      {
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+         /* Fix up the deflate header, if required */
+         optimize_cmf(comp->output, comp->input_len);
+#endif
+         /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
+          * function above to return Z_STREAM_END on an error (though it never
+          * does in the current versions of zlib.)
+          */
+         return Z_OK;
+      }
+
+      else
+         return ret;
+   }
+}
+
+/* Ship the compressed text out via chunk writes */
+static void
+png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
+{
+   png_uint_32 output_len = comp->output_len;
+   png_const_bytep output = comp->output;
+   png_uint_32 avail = (sizeof comp->output);
+   png_compression_buffer *next = png_ptr->zbuffer_list;
+
+   for (;;)
+   {
+      if (avail > output_len)
+         avail = output_len;
+
+      png_write_chunk_data(png_ptr, output, avail);
+
+      output_len -= avail;
+
+      if (output_len == 0 || next == NULL)
+         break;
+
+      avail = png_ptr->zbuffer_size;
+      output = next->output;
+      next = next->next;
+   }
+
+   /* This is an internal error; 'next' must have been NULL! */
+   if (output_len > 0)
+      png_error(png_ptr, "error writing ancillary chunked compressed data");
+}
+#endif /* WRITE_COMPRESSED_TEXT */
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information.  Note that the rest of this code depends upon this
+ * information being correct.
+ */
+void /* PRIVATE */
+png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
+    int bit_depth, int color_type, int compression_type, int filter_type,
+    int interlace_type)
+{
+   png_byte buf[13]; /* Buffer to store the IHDR info */
+   int is_invalid_depth;
+
+   png_debug(1, "in png_write_IHDR");
+
+   /* Check that we have valid input data from the application info */
+   switch (color_type)
+   {
+      case PNG_COLOR_TYPE_GRAY:
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+            case 8:
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+            case 16:
+#endif
+               png_ptr->channels = 1; break;
+
+            default:
+               png_error(png_ptr,
+                   "Invalid bit depth for grayscale image");
+         }
+         break;
+
+      case PNG_COLOR_TYPE_RGB:
+         is_invalid_depth = (bit_depth != 8);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         is_invalid_depth = (is_invalid_depth && bit_depth != 16);
+#endif
+         if (is_invalid_depth)
+            png_error(png_ptr, "Invalid bit depth for RGB image");
+
+         png_ptr->channels = 3;
+         break;
+
+      case PNG_COLOR_TYPE_PALETTE:
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+            case 8:
+               png_ptr->channels = 1;
+               break;
+
+            default:
+               png_error(png_ptr, "Invalid bit depth for paletted image");
+         }
+         break;
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         is_invalid_depth = (bit_depth != 8);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         is_invalid_depth = (is_invalid_depth && bit_depth != 16);
+#endif
+         if (is_invalid_depth)
+            png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
+
+         png_ptr->channels = 2;
+         break;
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         is_invalid_depth = (bit_depth != 8);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+         is_invalid_depth = (is_invalid_depth && bit_depth != 16);
+#endif
+         if (is_invalid_depth)
+            png_error(png_ptr, "Invalid bit depth for RGBA image");
+
+         png_ptr->channels = 4;
+         break;
+
+      default:
+         png_error(png_ptr, "Invalid image color type specified");
+   }
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Invalid compression type specified");
+      compression_type = PNG_COMPRESSION_TYPE_BASE;
+   }
+
+   /* Write filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not write a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if (
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+       !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+       ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
+       (color_type == PNG_COLOR_TYPE_RGB ||
+        color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
+       (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
+#endif
+       filter_type != PNG_FILTER_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Invalid filter type specified");
+      filter_type = PNG_FILTER_TYPE_BASE;
+   }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   if (interlace_type != PNG_INTERLACE_NONE &&
+       interlace_type != PNG_INTERLACE_ADAM7)
+   {
+      png_warning(png_ptr, "Invalid interlace type specified");
+      interlace_type = PNG_INTERLACE_ADAM7;
+   }
+#else
+   interlace_type=PNG_INTERLACE_NONE;
+#endif
+
+   /* Save the relevant information */
+   png_ptr->bit_depth = (png_byte)bit_depth;
+   png_ptr->color_type = (png_byte)color_type;
+   png_ptr->interlaced = (png_byte)interlace_type;
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+   png_ptr->filter_type = (png_byte)filter_type;
+#endif
+   png_ptr->compression_type = (png_byte)compression_type;
+   png_ptr->width = width;
+   png_ptr->height = height;
+
+   png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
+   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
+   /* Set the usr info, so any transformations can modify it */
+   png_ptr->usr_width = png_ptr->width;
+   png_ptr->usr_bit_depth = png_ptr->bit_depth;
+   png_ptr->usr_channels = png_ptr->channels;
+
+   /* Pack the header information into the buffer */
+   png_save_uint_32(buf, width);
+   png_save_uint_32(buf + 4, height);
+   buf[8] = (png_byte)bit_depth;
+   buf[9] = (png_byte)color_type;
+   buf[10] = (png_byte)compression_type;
+   buf[11] = (png_byte)filter_type;
+   buf[12] = (png_byte)interlace_type;
+
+   /* Write the chunk */
+   png_write_complete_chunk(png_ptr, png_IHDR, buf, 13);
+
+   if ((png_ptr->do_filter) == PNG_NO_FILTERS)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
+          png_ptr->bit_depth < 8)
+         png_ptr->do_filter = PNG_FILTER_NONE;
+
+      else
+         png_ptr->do_filter = PNG_ALL_FILTERS;
+   }
+
+   png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
+}
+
+/* Write the palette.  We are careful not to trust png_color to be in the
+ * correct order for PNG, so people can redefine it to any convenient
+ * structure.
+ */
+void /* PRIVATE */
+png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
+    png_uint_32 num_pal)
+{
+   png_uint_32 max_palette_length, i;
+   png_const_colorp pal_ptr;
+   png_byte buf[3];
+
+   png_debug(1, "in png_write_PLTE");
+
+   max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
+      (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
+
+   if ((
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+       (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
+#endif
+       num_pal == 0) || num_pal > max_palette_length)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         png_error(png_ptr, "Invalid number of colors in palette");
+      }
+
+      else
+      {
+         png_warning(png_ptr, "Invalid number of colors in palette");
+         return;
+      }
+   }
+
+   if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+   {
+      png_warning(png_ptr,
+          "Ignoring request to write a PLTE chunk in grayscale PNG");
+
+      return;
+   }
+
+   png_ptr->num_palette = (png_uint_16)num_pal;
+   png_debug1(3, "num_palette = %d", png_ptr->num_palette);
+
+   png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+
+   for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
+   {
+      buf[0] = pal_ptr->red;
+      buf[1] = pal_ptr->green;
+      buf[2] = pal_ptr->blue;
+      png_write_chunk_data(png_ptr, buf, 3);
+   }
+
+#else
+   /* This is a little slower but some buggy compilers need to do this
+    * instead
+    */
+   pal_ptr=palette;
+
+   for (i = 0; i < num_pal; i++)
+   {
+      buf[0] = pal_ptr[i].red;
+      buf[1] = pal_ptr[i].green;
+      buf[2] = pal_ptr[i].blue;
+      png_write_chunk_data(png_ptr, buf, 3);
+   }
+
+#endif
+   png_write_chunk_end(png_ptr);
+   png_ptr->mode |= PNG_HAVE_PLTE;
+}
+
+/* This is similar to png_text_compress, above, except that it does not require
+ * all of the data at once and, instead of buffering the compressed result,
+ * writes it as IDAT chunks.  Unlike png_text_compress it *can* png_error out
+ * because it calls the write interface.  As a result it does its own error
+ * reporting and does not return an error code.  In the event of error it will
+ * just call png_error.  The input data length may exceed 32-bits.  The 'flush'
+ * parameter is exactly the same as that to deflate, with the following
+ * meanings:
+ *
+ * Z_NO_FLUSH: normal incremental output of compressed data
+ * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush
+ * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
+ *
+ * The routine manages the acquire and release of the png_ptr->zstream by
+ * checking and (at the end) clearing png_ptr->zowner; it does some sanity
+ * checks on the 'mode' flags while doing this.
+ */
+void /* PRIVATE */
+png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
+    png_alloc_size_t input_len, int flush)
+{
+   if (png_ptr->zowner != png_IDAT)
+   {
+      /* First time.   Ensure we have a temporary buffer for compression and
+       * trim the buffer list if it has more than one entry to free memory.
+       * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been
+       * created at this point, but the check here is quick and safe.
+       */
+      if (png_ptr->zbuffer_list == NULL)
+      {
+         png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp,
+             png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
+         png_ptr->zbuffer_list->next = NULL;
+      }
+
+      else
+         png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next);
+
+      /* It is a terminal error if we can't claim the zstream. */
+      if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK)
+         png_error(png_ptr, png_ptr->zstream.msg);
+
+      /* The output state is maintained in png_ptr->zstream, so it must be
+       * initialized here after the claim.
+       */
+      png_ptr->zstream.next_out = png_ptr->zbuffer_list->output;
+      png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
+   }
+
+   /* Now loop reading and writing until all the input is consumed or an error
+    * terminates the operation.  The _out values are maintained across calls to
+    * this function, but the input must be reset each time.
+    */
+   png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
+   png_ptr->zstream.avail_in = 0; /* set below */
+   for (;;)
+   {
+      int ret;
+
+      /* INPUT: from the row data */
+      uInt avail = ZLIB_IO_MAX;
+
+      if (avail > input_len)
+         avail = (uInt)input_len; /* safe because of the check */
+
+      png_ptr->zstream.avail_in = avail;
+      input_len -= avail;
+
+      ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush);
+
+      /* Include as-yet unconsumed input */
+      input_len += png_ptr->zstream.avail_in;
+      png_ptr->zstream.avail_in = 0;
+
+      /* OUTPUT: write complete IDAT chunks when avail_out drops to zero. Note
+       * that these two zstream fields are preserved across the calls, therefore
+       * there is no need to set these up on entry to the loop.
+       */
+      if (png_ptr->zstream.avail_out == 0)
+      {
+         png_bytep data = png_ptr->zbuffer_list->output;
+         uInt size = png_ptr->zbuffer_size;
+
+         /* Write an IDAT containing the data then reset the buffer.  The
+          * first IDAT may need deflate header optimization.
+          */
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+            if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+                png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+               optimize_cmf(data, png_image_size(png_ptr));
+#endif
+
+         if (size > 0)
+            png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+         png_ptr->mode |= PNG_HAVE_IDAT;
+
+         png_ptr->zstream.next_out = data;
+         png_ptr->zstream.avail_out = size;
+
+         /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with
+          * the same flush parameter until it has finished output, for NO_FLUSH
+          * it doesn't matter.
+          */
+         if (ret == Z_OK && flush != Z_NO_FLUSH)
+            continue;
+      }
+
+      /* The order of these checks doesn't matter much; it just affects which
+       * possible error might be detected if multiple things go wrong at once.
+       */
+      if (ret == Z_OK) /* most likely return code! */
+      {
+         /* If all the input has been consumed then just return.  If Z_FINISH
+          * was used as the flush parameter something has gone wrong if we get
+          * here.
+          */
+         if (input_len == 0)
+         {
+            if (flush == Z_FINISH)
+               png_error(png_ptr, "Z_OK on Z_FINISH with output space");
+
+            return;
+         }
+      }
+
+      else if (ret == Z_STREAM_END && flush == Z_FINISH)
+      {
+         /* This is the end of the IDAT data; any pending output must be
+          * flushed.  For small PNG files we may still be at the beginning.
+          */
+         png_bytep data = png_ptr->zbuffer_list->output;
+         uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;
+
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+         if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+             png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+            optimize_cmf(data, png_image_size(png_ptr));
+#endif
+
+         if (size > 0)
+            png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+         png_ptr->zstream.avail_out = 0;
+         png_ptr->zstream.next_out = NULL;
+         png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;
+
+         png_ptr->zowner = 0; /* Release the stream */
+         return;
+      }
+
+      else
+      {
+         /* This is an error condition. */
+         png_zstream_error(png_ptr, ret);
+         png_error(png_ptr, png_ptr->zstream.msg);
+      }
+   }
+}
+
+/* Write an IEND chunk */
+void /* PRIVATE */
+png_write_IEND(png_structrp png_ptr)
+{
+   png_debug(1, "in png_write_IEND");
+
+   png_write_complete_chunk(png_ptr, png_IEND, NULL, 0);
+   png_ptr->mode |= PNG_HAVE_IEND;
+}
+
+#ifdef PNG_WRITE_gAMA_SUPPORTED
+/* Write a gAMA chunk */
+void /* PRIVATE */
+png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma)
+{
+   png_byte buf[4];
+
+   png_debug(1, "in png_write_gAMA");
+
+   /* file_gamma is saved in 1/100,000ths */
+   png_save_uint_32(buf, (png_uint_32)file_gamma);
+   png_write_complete_chunk(png_ptr, png_gAMA, buf, 4);
+}
+#endif
+
+#ifdef PNG_WRITE_sRGB_SUPPORTED
+/* Write a sRGB chunk */
+void /* PRIVATE */
+png_write_sRGB(png_structrp png_ptr, int srgb_intent)
+{
+   png_byte buf[1];
+
+   png_debug(1, "in png_write_sRGB");
+
+   if (srgb_intent >= PNG_sRGB_INTENT_LAST)
+      png_warning(png_ptr,
+          "Invalid sRGB rendering intent specified");
+
+   buf[0]=(png_byte)srgb_intent;
+   png_write_complete_chunk(png_ptr, png_sRGB, buf, 1);
+}
+#endif
+
+#ifdef PNG_WRITE_iCCP_SUPPORTED
+/* Write an iCCP chunk */
+void /* PRIVATE */
+png_write_iCCP(png_structrp png_ptr, png_const_charp name,
+    png_const_bytep profile)
+{
+   png_uint_32 name_len;
+   png_uint_32 profile_len;
+   png_byte new_name[81]; /* 1 byte for the compression byte */
+   compression_state comp;
+   png_uint_32 temp;
+
+   png_debug(1, "in png_write_iCCP");
+
+   /* These are all internal problems: the profile should have been checked
+    * before when it was stored.
+    */
+   if (profile == NULL)
+      png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */
+
+   profile_len = png_get_uint_32(profile);
+
+   if (profile_len < 132)
+      png_error(png_ptr, "ICC profile too short");
+
+   temp = (png_uint_32) (*(profile+8));
+   if (temp > 3 && (profile_len & 0x03))
+      png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");
+
+   {
+      png_uint_32 embedded_profile_len = png_get_uint_32(profile);
+
+      if (profile_len != embedded_profile_len)
+         png_error(png_ptr, "Profile length does not match profile");
+   }
+
+   name_len = png_check_keyword(png_ptr, name, new_name);
+
+   if (name_len == 0)
+      png_error(png_ptr, "iCCP: invalid keyword");
+
+   new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE;
+
+   /* Make sure we include the NULL after the name and the compression type */
+   ++name_len;
+
+   png_text_compress_init(&comp, profile, profile_len);
+
+   /* Allow for keyword terminator and compression byte */
+   if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK)
+      png_error(png_ptr, png_ptr->zstream.msg);
+
+   png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len);
+
+   png_write_chunk_data(png_ptr, new_name, name_len);
+
+   png_write_compressed_data_out(png_ptr, &comp);
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+/* Write a sPLT chunk */
+void /* PRIVATE */
+png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
+{
+   png_uint_32 name_len;
+   png_byte new_name[80];
+   png_byte entrybuf[10];
+   size_t entry_size = (spalette->depth == 8 ? 6 : 10);
+   size_t palette_size = entry_size * (size_t)spalette->nentries;
+   png_sPLT_entryp ep;
+#ifndef PNG_POINTER_INDEXING_SUPPORTED
+   int i;
+#endif
+
+   png_debug(1, "in png_write_sPLT");
+
+   name_len = png_check_keyword(png_ptr, spalette->name, new_name);
+
+   if (name_len == 0)
+      png_error(png_ptr, "sPLT: invalid keyword");
+
+   /* Make sure we include the NULL after the name */
+   png_write_chunk_header(png_ptr, png_sPLT,
+       (png_uint_32)(name_len + 2 + palette_size));
+
+   png_write_chunk_data(png_ptr, (png_bytep)new_name, (size_t)(name_len + 1));
+
+   png_write_chunk_data(png_ptr, &spalette->depth, 1);
+
+   /* Loop through each palette entry, writing appropriately */
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+   for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
+   {
+      if (spalette->depth == 8)
+      {
+         entrybuf[0] = (png_byte)ep->red;
+         entrybuf[1] = (png_byte)ep->green;
+         entrybuf[2] = (png_byte)ep->blue;
+         entrybuf[3] = (png_byte)ep->alpha;
+         png_save_uint_16(entrybuf + 4, ep->frequency);
+      }
+
+      else
+      {
+         png_save_uint_16(entrybuf + 0, ep->red);
+         png_save_uint_16(entrybuf + 2, ep->green);
+         png_save_uint_16(entrybuf + 4, ep->blue);
+         png_save_uint_16(entrybuf + 6, ep->alpha);
+         png_save_uint_16(entrybuf + 8, ep->frequency);
+      }
+
+      png_write_chunk_data(png_ptr, entrybuf, entry_size);
+   }
+#else
+   ep=spalette->entries;
+   for (i = 0; i>spalette->nentries; i++)
+   {
+      if (spalette->depth == 8)
+      {
+         entrybuf[0] = (png_byte)ep[i].red;
+         entrybuf[1] = (png_byte)ep[i].green;
+         entrybuf[2] = (png_byte)ep[i].blue;
+         entrybuf[3] = (png_byte)ep[i].alpha;
+         png_save_uint_16(entrybuf + 4, ep[i].frequency);
+      }
+
+      else
+      {
+         png_save_uint_16(entrybuf + 0, ep[i].red);
+         png_save_uint_16(entrybuf + 2, ep[i].green);
+         png_save_uint_16(entrybuf + 4, ep[i].blue);
+         png_save_uint_16(entrybuf + 6, ep[i].alpha);
+         png_save_uint_16(entrybuf + 8, ep[i].frequency);
+      }
+
+      png_write_chunk_data(png_ptr, entrybuf, entry_size);
+   }
+#endif
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+/* Write the sBIT chunk */
+void /* PRIVATE */
+png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
+{
+   png_byte buf[4];
+   size_t size;
+
+   png_debug(1, "in png_write_sBIT");
+
+   /* Make sure we don't depend upon the order of PNG_COLOR_8 */
+   if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_byte maxbits;
+
+      maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
+          png_ptr->usr_bit_depth);
+
+      if (sbit->red == 0 || sbit->red > maxbits ||
+          sbit->green == 0 || sbit->green > maxbits ||
+          sbit->blue == 0 || sbit->blue > maxbits)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
+
+      buf[0] = sbit->red;
+      buf[1] = sbit->green;
+      buf[2] = sbit->blue;
+      size = 3;
+   }
+
+   else
+   {
+      if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
+
+      buf[0] = sbit->gray;
+      size = 1;
+   }
+
+   if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
+   {
+      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
+
+      buf[size++] = sbit->alpha;
+   }
+
+   png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
+}
+#endif
+
+#ifdef PNG_WRITE_cHRM_SUPPORTED
+/* Write the cHRM chunk */
+void /* PRIVATE */
+png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy)
+{
+   png_byte buf[32];
+
+   png_debug(1, "in png_write_cHRM");
+
+   /* Each value is saved in 1/100,000ths */
+   png_save_int_32(buf,      xy->whitex);
+   png_save_int_32(buf +  4, xy->whitey);
+
+   png_save_int_32(buf +  8, xy->redx);
+   png_save_int_32(buf + 12, xy->redy);
+
+   png_save_int_32(buf + 16, xy->greenx);
+   png_save_int_32(buf + 20, xy->greeny);
+
+   png_save_int_32(buf + 24, xy->bluex);
+   png_save_int_32(buf + 28, xy->bluey);
+
+   png_write_complete_chunk(png_ptr, png_cHRM, buf, 32);
+}
+#endif
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+/* Write the tRNS chunk */
+void /* PRIVATE */
+png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
+    png_const_color_16p tran, int num_trans, int color_type)
+{
+   png_byte buf[6];
+
+   png_debug(1, "in png_write_tRNS");
+
+   if (color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
+      {
+         png_app_warning(png_ptr,
+             "Invalid number of transparent colors specified");
+         return;
+      }
+
+      /* Write the chunk out as it is */
+      png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
+          (size_t)num_trans);
+   }
+
+   else if (color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      /* One 16-bit value */
+      if (tran->gray >= (1 << png_ptr->bit_depth))
+      {
+         png_app_warning(png_ptr,
+             "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
+
+         return;
+      }
+
+      png_save_uint_16(buf, tran->gray);
+      png_write_complete_chunk(png_ptr, png_tRNS, buf, 2);
+   }
+
+   else if (color_type == PNG_COLOR_TYPE_RGB)
+   {
+      /* Three 16-bit values */
+      png_save_uint_16(buf, tran->red);
+      png_save_uint_16(buf + 2, tran->green);
+      png_save_uint_16(buf + 4, tran->blue);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
+#else
+      if ((buf[0] | buf[2] | buf[4]) != 0)
+#endif
+      {
+         png_app_warning(png_ptr,
+             "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
+         return;
+      }
+
+      png_write_complete_chunk(png_ptr, png_tRNS, buf, 6);
+   }
+
+   else
+   {
+      png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+/* Write the background chunk */
+void /* PRIVATE */
+png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
+{
+   png_byte buf[6];
+
+   png_debug(1, "in png_write_bKGD");
+
+   if (color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+          (png_ptr->num_palette != 0 ||
+          (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
+#endif
+         back->index >= png_ptr->num_palette)
+      {
+         png_warning(png_ptr, "Invalid background palette index");
+         return;
+      }
+
+      buf[0] = back->index;
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, 1);
+   }
+
+   else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      png_save_uint_16(buf, back->red);
+      png_save_uint_16(buf + 2, back->green);
+      png_save_uint_16(buf + 4, back->blue);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
+#else
+      if ((buf[0] | buf[2] | buf[4]) != 0)
+#endif
+      {
+         png_warning(png_ptr,
+             "Ignoring attempt to write 16-bit bKGD chunk "
+             "when bit_depth is 8");
+
+         return;
+      }
+
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, 6);
+   }
+
+   else
+   {
+      if (back->gray >= (1 << png_ptr->bit_depth))
+      {
+         png_warning(png_ptr,
+             "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
+
+         return;
+      }
+
+      png_save_uint_16(buf, back->gray);
+      png_write_complete_chunk(png_ptr, png_bKGD, buf, 2);
+   }
+}
+#endif
+
+#ifdef PNG_WRITE_eXIf_SUPPORTED
+/* Write the Exif data */
+void /* PRIVATE */
+png_write_eXIf(png_structrp png_ptr, png_bytep exif, int num_exif)
+{
+   int i;
+   png_byte buf[1];
+
+   png_debug(1, "in png_write_eXIf");
+
+   png_write_chunk_header(png_ptr, png_eXIf, (png_uint_32)(num_exif));
+
+   for (i = 0; i < num_exif; i++)
+   {
+      buf[0] = exif[i];
+      png_write_chunk_data(png_ptr, buf, 1);
+   }
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+/* Write the histogram */
+void /* PRIVATE */
+png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)
+{
+   int i;
+   png_byte buf[3];
+
+   png_debug(1, "in png_write_hIST");
+
+   if (num_hist > (int)png_ptr->num_palette)
+   {
+      png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
+          png_ptr->num_palette);
+
+      png_warning(png_ptr, "Invalid number of histogram entries specified");
+      return;
+   }
+
+   png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
+
+   for (i = 0; i < num_hist; i++)
+   {
+      png_save_uint_16(buf, hist[i]);
+      png_write_chunk_data(png_ptr, buf, 2);
+   }
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+/* Write a tEXt chunk */
+void /* PRIVATE */
+png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
+    size_t text_len)
+{
+   png_uint_32 key_len;
+   png_byte new_key[80];
+
+   png_debug(1, "in png_write_tEXt");
+
+   key_len = png_check_keyword(png_ptr, key, new_key);
+
+   if (key_len == 0)
+      png_error(png_ptr, "tEXt: invalid keyword");
+
+   if (text == NULL || *text == '\0')
+      text_len = 0;
+
+   else
+      text_len = strlen(text);
+
+   if (text_len > PNG_UINT_31_MAX - (key_len+1))
+      png_error(png_ptr, "tEXt: text too long");
+
+   /* Make sure we include the 0 after the key */
+   png_write_chunk_header(png_ptr, png_tEXt,
+       (png_uint_32)/*checked above*/(key_len + text_len + 1));
+   /*
+    * We leave it to the application to meet PNG-1.0 requirements on the
+    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
+    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
+    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+    */
+   png_write_chunk_data(png_ptr, new_key, key_len + 1);
+
+   if (text_len != 0)
+      png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+/* Write a compressed text chunk */
+void /* PRIVATE */
+png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
+    int compression)
+{
+   png_uint_32 key_len;
+   png_byte new_key[81];
+   compression_state comp;
+
+   png_debug(1, "in png_write_zTXt");
+
+   if (compression == PNG_TEXT_COMPRESSION_NONE)
+   {
+      png_write_tEXt(png_ptr, key, text, 0);
+      return;
+   }
+
+   if (compression != PNG_TEXT_COMPRESSION_zTXt)
+      png_error(png_ptr, "zTXt: invalid compression type");
+
+   key_len = png_check_keyword(png_ptr, key, new_key);
+
+   if (key_len == 0)
+      png_error(png_ptr, "zTXt: invalid keyword");
+
+   /* Add the compression method and 1 for the keyword separator. */
+   new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
+   ++key_len;
+
+   /* Compute the compressed data; do it now for the length */
+   png_text_compress_init(&comp, (png_const_bytep)text,
+       text == NULL ? 0 : strlen(text));
+
+   if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK)
+      png_error(png_ptr, png_ptr->zstream.msg);
+
+   /* Write start of chunk */
+   png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len);
+
+   /* Write key */
+   png_write_chunk_data(png_ptr, new_key, key_len);
+
+   /* Write the compressed data */
+   png_write_compressed_data_out(png_ptr, &comp);
+
+   /* Close the chunk */
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+/* Write an iTXt chunk */
+void /* PRIVATE */
+png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
+    png_const_charp lang, png_const_charp lang_key, png_const_charp text)
+{
+   png_uint_32 key_len, prefix_len;
+   size_t lang_len, lang_key_len;
+   png_byte new_key[82];
+   compression_state comp;
+
+   png_debug(1, "in png_write_iTXt");
+
+   key_len = png_check_keyword(png_ptr, key, new_key);
+
+   if (key_len == 0)
+      png_error(png_ptr, "iTXt: invalid keyword");
+
+   /* Set the compression flag */
+   switch (compression)
+   {
+      case PNG_ITXT_COMPRESSION_NONE:
+      case PNG_TEXT_COMPRESSION_NONE:
+         compression = new_key[++key_len] = 0; /* no compression */
+         break;
+
+      case PNG_TEXT_COMPRESSION_zTXt:
+      case PNG_ITXT_COMPRESSION_zTXt:
+         compression = new_key[++key_len] = 1; /* compressed */
+         break;
+
+      default:
+         png_error(png_ptr, "iTXt: invalid compression");
+   }
+
+   new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
+   ++key_len; /* for the keywod separator */
+
+   /* We leave it to the application to meet PNG-1.0 requirements on the
+    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
+    * any non-Latin-1 characters except for NEWLINE.  ISO PNG, however,
+    * specifies that the text is UTF-8 and this really doesn't require any
+    * checking.
+    *
+    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+    *
+    * TODO: validate the language tag correctly (see the spec.)
+    */
+   if (lang == NULL) lang = ""; /* empty language is valid */
+   lang_len = strlen(lang)+1;
+   if (lang_key == NULL) lang_key = ""; /* may be empty */
+   lang_key_len = strlen(lang_key)+1;
+   if (text == NULL) text = ""; /* may be empty */
+
+   prefix_len = key_len;
+   if (lang_len > PNG_UINT_31_MAX-prefix_len)
+      prefix_len = PNG_UINT_31_MAX;
+   else
+      prefix_len = (png_uint_32)(prefix_len + lang_len);
+
+   if (lang_key_len > PNG_UINT_31_MAX-prefix_len)
+      prefix_len = PNG_UINT_31_MAX;
+   else
+      prefix_len = (png_uint_32)(prefix_len + lang_key_len);
+
+   png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));
+
+   if (compression != 0)
+   {
+      if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)
+         png_error(png_ptr, png_ptr->zstream.msg);
+   }
+
+   else
+   {
+      if (comp.input_len > PNG_UINT_31_MAX-prefix_len)
+         png_error(png_ptr, "iTXt: uncompressed text too long");
+
+      /* So the string will fit in a chunk: */
+      comp.output_len = (png_uint_32)/*SAFE*/comp.input_len;
+   }
+
+   png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len);
+
+   png_write_chunk_data(png_ptr, new_key, key_len);
+
+   png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len);
+
+   png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);
+
+   if (compression != 0)
+      png_write_compressed_data_out(png_ptr, &comp);
+
+   else
+      png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.output_len);
+
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+/* Write the oFFs chunk */
+void /* PRIVATE */
+png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
+    int unit_type)
+{
+   png_byte buf[9];
+
+   png_debug(1, "in png_write_oFFs");
+
+   if (unit_type >= PNG_OFFSET_LAST)
+      png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
+
+   png_save_int_32(buf, x_offset);
+   png_save_int_32(buf + 4, y_offset);
+   buf[8] = (png_byte)unit_type;
+
+   png_write_complete_chunk(png_ptr, png_oFFs, buf, 9);
+}
+#endif
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+/* Write the pCAL chunk (described in the PNG extensions document) */
+void /* PRIVATE */
+png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
+    png_int_32 X1, int type, int nparams, png_const_charp units,
+    png_charpp params)
+{
+   png_uint_32 purpose_len;
+   size_t units_len, total_len;
+   size_t *params_len;
+   png_byte buf[10];
+   png_byte new_purpose[80];
+   int i;
+
+   png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
+
+   if (type >= PNG_EQUATION_LAST)
+      png_error(png_ptr, "Unrecognized equation type for pCAL chunk");
+
+   purpose_len = png_check_keyword(png_ptr, purpose, new_purpose);
+
+   if (purpose_len == 0)
+      png_error(png_ptr, "pCAL: invalid keyword");
+
+   ++purpose_len; /* terminator */
+
+   png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
+   units_len = strlen(units) + (nparams == 0 ? 0 : 1);
+   png_debug1(3, "pCAL units length = %d", (int)units_len);
+   total_len = purpose_len + units_len + 10;
+
+   params_len = (size_t *)png_malloc(png_ptr,
+       (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (size_t))));
+
+   /* Find the length of each parameter, making sure we don't count the
+    * null terminator for the last parameter.
+    */
+   for (i = 0; i < nparams; i++)
+   {
+      params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
+      png_debug2(3, "pCAL parameter %d length = %lu", i,
+          (unsigned long)params_len[i]);
+      total_len += params_len[i];
+   }
+
+   png_debug1(3, "pCAL total length = %d", (int)total_len);
+   png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
+   png_write_chunk_data(png_ptr, new_purpose, purpose_len);
+   png_save_int_32(buf, X0);
+   png_save_int_32(buf + 4, X1);
+   buf[8] = (png_byte)type;
+   buf[9] = (png_byte)nparams;
+   png_write_chunk_data(png_ptr, buf, 10);
+   png_write_chunk_data(png_ptr, (png_const_bytep)units, (size_t)units_len);
+
+   for (i = 0; i < nparams; i++)
+   {
+      png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
+   }
+
+   png_free(png_ptr, params_len);
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+/* Write the sCAL chunk */
+void /* PRIVATE */
+png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,
+    png_const_charp height)
+{
+   png_byte buf[64];
+   size_t wlen, hlen, total_len;
+
+   png_debug(1, "in png_write_sCAL_s");
+
+   wlen = strlen(width);
+   hlen = strlen(height);
+   total_len = wlen + hlen + 2;
+
+   if (total_len > 64)
+   {
+      png_warning(png_ptr, "Can't write sCAL (buffer too small)");
+      return;
+   }
+
+   buf[0] = (png_byte)unit;
+   memcpy(buf + 1, width, wlen + 1);      /* Append the '\0' here */
+   memcpy(buf + wlen + 2, height, hlen);  /* Do NOT append the '\0' here */
+
+   png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
+   png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
+}
+#endif
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+/* Write the pHYs chunk */
+void /* PRIVATE */
+png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit,
+    png_uint_32 y_pixels_per_unit,
+    int unit_type)
+{
+   png_byte buf[9];
+
+   png_debug(1, "in png_write_pHYs");
+
+   if (unit_type >= PNG_RESOLUTION_LAST)
+      png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
+
+   png_save_uint_32(buf, x_pixels_per_unit);
+   png_save_uint_32(buf + 4, y_pixels_per_unit);
+   buf[8] = (png_byte)unit_type;
+
+   png_write_complete_chunk(png_ptr, png_pHYs, buf, 9);
+}
+#endif
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+/* Write the tIME chunk.  Use either png_convert_from_struct_tm()
+ * or png_convert_from_time_t(), or fill in the structure yourself.
+ */
+void /* PRIVATE */
+png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)
+{
+   png_byte buf[7];
+
+   png_debug(1, "in png_write_tIME");
+
+   if (mod_time->month  > 12 || mod_time->month  < 1 ||
+       mod_time->day    > 31 || mod_time->day    < 1 ||
+       mod_time->hour   > 23 || mod_time->second > 60)
+   {
+      png_warning(png_ptr, "Invalid time specified for tIME chunk");
+      return;
+   }
+
+   png_save_uint_16(buf, mod_time->year);
+   buf[2] = mod_time->month;
+   buf[3] = mod_time->day;
+   buf[4] = mod_time->hour;
+   buf[5] = mod_time->minute;
+   buf[6] = mod_time->second;
+
+   png_write_complete_chunk(png_ptr, png_tIME, buf, 7);
+}
+#endif
+
+/* Initializes the row writing capability of libpng */
+void /* PRIVATE */
+png_write_start_row(png_structrp png_ptr)
+{
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+   png_alloc_size_t buf_size;
+   int usr_pixel_depth;
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   png_byte filters;
+#endif
+
+   png_debug(1, "in png_write_start_row");
+
+   usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
+   buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
+
+   /* 1.5.6: added to allow checking in the row write code. */
+   png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
+   png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
+
+   /* Set up row buffer */
+   png_ptr->row_buf = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
+
+   png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   filters = png_ptr->do_filter;
+
+   if (png_ptr->height == 1)
+      filters &= 0xff & ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+   if (png_ptr->width == 1)
+      filters &= 0xff & ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+   if (filters == 0)
+      filters = PNG_FILTER_NONE;
+
+   png_ptr->do_filter = filters;
+
+   if (((filters & (PNG_FILTER_SUB | PNG_FILTER_UP | PNG_FILTER_AVG |
+       PNG_FILTER_PAETH)) != 0) && png_ptr->try_row == NULL)
+   {
+      int num_filters = 0;
+
+      png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
+
+      if (filters & PNG_FILTER_SUB)
+         num_filters++;
+
+      if (filters & PNG_FILTER_UP)
+         num_filters++;
+
+      if (filters & PNG_FILTER_AVG)
+         num_filters++;
+
+      if (filters & PNG_FILTER_PAETH)
+         num_filters++;
+
+      if (num_filters > 1)
+         png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr,
+             buf_size));
+   }
+
+   /* We only need to keep the previous row if we are using one of the following
+    * filters.
+    */
+   if ((filters & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
+      png_ptr->prev_row = png_voidcast(png_bytep,
+          png_calloc(png_ptr, buf_size));
+#endif /* WRITE_FILTER */
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* If interlaced, we need to set up width and height of pass */
+   if (png_ptr->interlaced != 0)
+   {
+      if ((png_ptr->transformations & PNG_INTERLACE) == 0)
+      {
+         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+             png_pass_ystart[0]) / png_pass_yinc[0];
+
+         png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
+             png_pass_start[0]) / png_pass_inc[0];
+      }
+
+      else
+      {
+         png_ptr->num_rows = png_ptr->height;
+         png_ptr->usr_width = png_ptr->width;
+      }
+   }
+
+   else
+#endif
+   {
+      png_ptr->num_rows = png_ptr->height;
+      png_ptr->usr_width = png_ptr->width;
+   }
+}
+
+/* Internal use only.  Called when finished processing a row of data. */
+void /* PRIVATE */
+png_write_finish_row(png_structrp png_ptr)
+{
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* Start of interlace block in the y direction */
+   static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* Offset to next interlace block in the y direction */
+   static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+   png_debug(1, "in png_write_finish_row");
+
+   /* Next row */
+   png_ptr->row_number++;
+
+   /* See if we are done */
+   if (png_ptr->row_number < png_ptr->num_rows)
+      return;
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* If interlaced, go to next pass */
+   if (png_ptr->interlaced != 0)
+   {
+      png_ptr->row_number = 0;
+      if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+      {
+         png_ptr->pass++;
+      }
+
+      else
+      {
+         /* Loop until we find a non-zero width or height pass */
+         do
+         {
+            png_ptr->pass++;
+
+            if (png_ptr->pass >= 7)
+               break;
+
+            png_ptr->usr_width = (png_ptr->width +
+                png_pass_inc[png_ptr->pass] - 1 -
+                png_pass_start[png_ptr->pass]) /
+                png_pass_inc[png_ptr->pass];
+
+            png_ptr->num_rows = (png_ptr->height +
+                png_pass_yinc[png_ptr->pass] - 1 -
+                png_pass_ystart[png_ptr->pass]) /
+                png_pass_yinc[png_ptr->pass];
+
+            if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+               break;
+
+         } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
+
+      }
+
+      /* Reset the row above the image for the next pass */
+      if (png_ptr->pass < 7)
+      {
+         if (png_ptr->prev_row != NULL)
+            memset(png_ptr->prev_row, 0,
+                PNG_ROWBYTES(png_ptr->usr_channels *
+                png_ptr->usr_bit_depth, png_ptr->width) + 1);
+
+         return;
+      }
+   }
+#endif
+
+   /* If we get here, we've just written the last row, so we need
+      to flush the compressor */
+   png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH);
+}
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+/* Pick out the correct pixels for the interlace pass.
+ * The basic idea here is to go through the row with a source
+ * pointer and a destination pointer (sp and dp), and copy the
+ * correct pixels for the pass.  As the row gets compacted,
+ * sp will always be >= dp, so we should never overwrite anything.
+ * See the default: case for the easiest code to understand.
+ */
+void /* PRIVATE */
+png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
+{
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* Start of interlace block */
+   static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* Offset to next interlace block */
+   static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   png_debug(1, "in png_do_write_interlace");
+
+   /* We don't have to do anything on the last pass (6) */
+   if (pass < 6)
+   {
+      /* Each pixel depth is handled separately */
+      switch (row_info->pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            unsigned int shift;
+            int d;
+            int value;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            dp = row;
+            d = 0;
+            shift = 7;
+
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               sp = row + (size_t)(i >> 3);
+               value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
+               d |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 7;
+                  *dp++ = (png_byte)d;
+                  d = 0;
+               }
+
+               else
+                  shift--;
+
+            }
+            if (shift != 7)
+               *dp = (png_byte)d;
+
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            unsigned int shift;
+            int d;
+            int value;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            dp = row;
+            shift = 6;
+            d = 0;
+
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               sp = row + (size_t)(i >> 2);
+               value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
+               d |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 6;
+                  *dp++ = (png_byte)d;
+                  d = 0;
+               }
+
+               else
+                  shift -= 2;
+            }
+            if (shift != 6)
+               *dp = (png_byte)d;
+
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            unsigned int shift;
+            int d;
+            int value;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            dp = row;
+            shift = 4;
+            d = 0;
+            for (i = png_pass_start[pass]; i < row_width;
+                i += png_pass_inc[pass])
+            {
+               sp = row + (size_t)(i >> 1);
+               value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
+               d |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 4;
+                  *dp++ = (png_byte)d;
+                  d = 0;
+               }
+
+               else
+                  shift -= 4;
+            }
+            if (shift != 4)
+               *dp = (png_byte)d;
+
+            break;
+         }
+
+         default:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+            size_t pixel_bytes;
+
+            /* Start at the beginning */
+            dp = row;
+
+            /* Find out how many bytes each pixel takes up */
+            pixel_bytes = (row_info->pixel_depth >> 3);
+
+            /* Loop through the row, only looking at the pixels that matter */
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               /* Find out where the original pixel is */
+               sp = row + (size_t)i * pixel_bytes;
+
+               /* Move the pixel */
+               if (dp != sp)
+                  memcpy(dp, sp, pixel_bytes);
+
+               /* Next pixel */
+               dp += pixel_bytes;
+            }
+            break;
+         }
+      }
+      /* Set new row width */
+      row_info->width = (row_info->width +
+          png_pass_inc[pass] - 1 -
+          png_pass_start[pass]) /
+          png_pass_inc[pass];
+
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+          row_info->width);
+   }
+}
+#endif
+
+
+/* This filters the row, chooses which filter to use, if it has not already
+ * been specified by the application, and then writes the row out with the
+ * chosen filter.
+ */
+static void /* PRIVATE */
+png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
+    size_t row_bytes);
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+static size_t /* PRIVATE */
+png_setup_sub_row(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes, size_t lmins)
+{
+   png_bytep rp, dp, lp;
+   size_t i;
+   size_t sum = 0;
+   unsigned int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
+        i++, rp++, dp++)
+   {
+      v = *dp = *rp;
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes;
+      i++, rp++, lp++, dp++)
+   {
+      v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return sum;
+}
+
+static void /* PRIVATE */
+png_setup_sub_row_only(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes)
+{
+   png_bytep rp, dp, lp;
+   size_t i;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
+        i++, rp++, dp++)
+   {
+      *dp = *rp;
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes;
+      i++, rp++, lp++, dp++)
+   {
+      *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+   }
+}
+
+static size_t /* PRIVATE */
+png_setup_up_row(png_structrp png_ptr, size_t row_bytes, size_t lmins)
+{
+   png_bytep rp, dp, pp;
+   size_t i;
+   size_t sum = 0;
+   unsigned int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < row_bytes;
+       i++, rp++, pp++, dp++)
+   {
+      v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return sum;
+}
+static void /* PRIVATE */
+png_setup_up_row_only(png_structrp png_ptr, size_t row_bytes)
+{
+   png_bytep rp, dp, pp;
+   size_t i;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < row_bytes;
+       i++, rp++, pp++, dp++)
+   {
+      *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+   }
+}
+
+static size_t /* PRIVATE */
+png_setup_avg_row(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes, size_t lmins)
+{
+   png_bytep rp, dp, pp, lp;
+   png_uint_32 i;
+   size_t sum = 0;
+   unsigned int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
+   {
+      v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+          & 0xff);
+
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return sum;
+}
+static void /* PRIVATE */
+png_setup_avg_row_only(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes)
+{
+   png_bytep rp, dp, pp, lp;
+   png_uint_32 i;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
+   {
+      *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+          & 0xff);
+   }
+}
+
+static size_t /* PRIVATE */
+png_setup_paeth_row(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes, size_t lmins)
+{
+   png_bytep rp, dp, pp, cp, lp;
+   size_t i;
+   size_t sum = 0;
+   unsigned int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+   }
+
+   for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
+        i++)
+   {
+      int a, b, c, pa, pb, pc, p;
+
+      b = *pp++;
+      c = *cp++;
+      a = *lp++;
+
+      p = b - c;
+      pc = a - c;
+
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+      p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+      v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+
+#ifdef PNG_USE_ABS
+      sum += 128 - abs((int)v - 128);
+#else
+      sum += (v < 128) ? v : 256 - v;
+#endif
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return sum;
+}
+static void /* PRIVATE */
+png_setup_paeth_row_only(png_structrp png_ptr, png_uint_32 bpp,
+    size_t row_bytes)
+{
+   png_bytep rp, dp, pp, cp, lp;
+   size_t i;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+   }
+
+   for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
+        i++)
+   {
+      int a, b, c, pa, pb, pc, p;
+
+      b = *pp++;
+      c = *cp++;
+      a = *lp++;
+
+      p = b - c;
+      pc = a - c;
+
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+      p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+      *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+   }
+}
+#endif /* WRITE_FILTER */
+
+void /* PRIVATE */
+png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
+{
+#ifndef PNG_WRITE_FILTER_SUPPORTED
+   png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
+#else
+   unsigned int filter_to_do = png_ptr->do_filter;
+   png_bytep row_buf;
+   png_bytep best_row;
+   png_uint_32 bpp;
+   size_t mins;
+   size_t row_bytes = row_info->rowbytes;
+
+   png_debug(1, "in png_write_find_filter");
+
+   /* Find out how many bytes offset each pixel is */
+   bpp = (row_info->pixel_depth + 7) >> 3;
+
+   row_buf = png_ptr->row_buf;
+   mins = PNG_SIZE_MAX - 256/* so we can detect potential overflow of the
+                               running sum */;
+
+   /* The prediction method we use is to find which method provides the
+    * smallest value when summing the absolute values of the distances
+    * from zero, using anything >= 128 as negative numbers.  This is known
+    * as the "minimum sum of absolute differences" heuristic.  Other
+    * heuristics are the "weighted minimum sum of absolute differences"
+    * (experimental and can in theory improve compression), and the "zlib
+    * predictive" method (not implemented yet), which does test compressions
+    * of lines using different filter methods, and then chooses the
+    * (series of) filter(s) that give minimum compressed data size (VERY
+    * computationally expensive).
+    *
+    * GRR 980525:  consider also
+    *
+    *   (1) minimum sum of absolute differences from running average (i.e.,
+    *       keep running sum of non-absolute differences & count of bytes)
+    *       [track dispersion, too?  restart average if dispersion too large?]
+    *
+    *  (1b) minimum sum of absolute differences from sliding average, probably
+    *       with window size <= deflate window (usually 32K)
+    *
+    *   (2) minimum sum of squared differences from zero or running average
+    *       (i.e., ~ root-mean-square approach)
+    */
+
+
+   /* We don't need to test the 'no filter' case if this is the only filter
+    * that has been chosen, as it doesn't actually do anything to the data.
+    */
+   best_row = png_ptr->row_buf;
+
+   if (PNG_SIZE_MAX/128 <= row_bytes)
+   {
+      /* Overflow can occur in the calculation, just select the lowest set
+       * filter.
+       */
+      filter_to_do &= 0U-filter_to_do;
+   }
+   else if ((filter_to_do & PNG_FILTER_NONE) != 0 &&
+         filter_to_do != PNG_FILTER_NONE)
+   {
+      /* Overflow not possible and multiple filters in the list, including the
+       * 'none' filter.
+       */
+      png_bytep rp;
+      size_t sum = 0;
+      size_t i;
+      unsigned int v;
+
+      {
+         for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
+         {
+            v = *rp;
+#ifdef PNG_USE_ABS
+            sum += 128 - abs((int)v - 128);
+#else
+            sum += (v < 128) ? v : 256 - v;
+#endif
+         }
+      }
+
+      mins = sum;
+   }
+
+   /* Sub filter */
+   if (filter_to_do == PNG_FILTER_SUB)
+   /* It's the only filter so no testing is needed */
+   {
+      png_setup_sub_row_only(png_ptr, bpp, row_bytes);
+      best_row = png_ptr->try_row;
+   }
+
+   else if ((filter_to_do & PNG_FILTER_SUB) != 0)
+   {
+      size_t sum;
+      size_t lmins = mins;
+
+      sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins);
+
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
+      }
+   }
+
+   /* Up filter */
+   if (filter_to_do == PNG_FILTER_UP)
+   {
+      png_setup_up_row_only(png_ptr, row_bytes);
+      best_row = png_ptr->try_row;
+   }
+
+   else if ((filter_to_do & PNG_FILTER_UP) != 0)
+   {
+      size_t sum;
+      size_t lmins = mins;
+
+      sum = png_setup_up_row(png_ptr, row_bytes, lmins);
+
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
+      }
+   }
+
+   /* Avg filter */
+   if (filter_to_do == PNG_FILTER_AVG)
+   {
+      png_setup_avg_row_only(png_ptr, bpp, row_bytes);
+      best_row = png_ptr->try_row;
+   }
+
+   else if ((filter_to_do & PNG_FILTER_AVG) != 0)
+   {
+      size_t sum;
+      size_t lmins = mins;
+
+      sum= png_setup_avg_row(png_ptr, bpp, row_bytes, lmins);
+
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
+      }
+   }
+
+   /* Paeth filter */
+   if (filter_to_do == PNG_FILTER_PAETH)
+   {
+      png_setup_paeth_row_only(png_ptr, bpp, row_bytes);
+      best_row = png_ptr->try_row;
+   }
+
+   else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
+   {
+      size_t sum;
+      size_t lmins = mins;
+
+      sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins);
+
+      if (sum < mins)
+      {
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
+      }
+   }
+
+   /* Do the actual writing of the filtered row data from the chosen filter. */
+   png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
+
+#endif /* WRITE_FILTER */
+}
+
+
+/* Do the actual writing of a previously filtered row. */
+static void
+png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
+    size_t full_row_length/*includes filter byte*/)
+{
+   png_debug(1, "in png_write_filtered_row");
+
+   png_debug1(2, "filter = %d", filtered_row[0]);
+
+   png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   /* Swap the current and previous rows */
+   if (png_ptr->prev_row != NULL)
+   {
+      png_bytep tptr;
+
+      tptr = png_ptr->prev_row;
+      png_ptr->prev_row = png_ptr->row_buf;
+      png_ptr->row_buf = tptr;
+   }
+#endif /* WRITE_FILTER */
+
+   /* Finish row - updates counters and flushes zlib if last row */
+   png_write_finish_row(png_ptr);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+   png_ptr->flush_rows++;
+
+   if (png_ptr->flush_dist > 0 &&
+       png_ptr->flush_rows >= png_ptr->flush_dist)
+   {
+      png_write_flush(png_ptr);
+   }
+#endif /* WRITE_FLUSH */
+}
+#endif /* WRITE */
Index: /trunk/src/libs/libpng-1.6.45/powerpc/filter_vsx_intrinsics.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/powerpc/filter_vsx_intrinsics.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/powerpc/filter_vsx_intrinsics.c	(revision 107811)
@@ -0,0 +1,768 @@
+/* filter_vsx_intrinsics.c - PowerPC optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2017 Glenn Randers-Pehrson
+ * Written by Vadim Barkov, 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* This code requires -maltivec and -mvsx on the command line: */
+#if PNG_POWERPC_VSX_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+#include <altivec.h>
+
+#if PNG_POWERPC_VSX_OPT > 0
+
+#ifndef __VSX__
+#  error "This code requires VSX support (POWER7 and later). Please provide -mvsx compiler flag."
+#endif
+
+#define vec_ld_unaligned(vec,data) vec = vec_vsx_ld(0,data)
+#define vec_st_unaligned(vec,data) vec_vsx_st(vec,0,data)
+
+
+/* Functions in this file look at most 3 pixels (a,b,c) to predict the 4th (d).
+ * They're positioned like this:
+ *    prev:  c b
+ *    row:   a d
+ * The Sub filter predicts d=a, Avg d=(a+b)/2, and Paeth predicts d to be
+ * whichever of a, b, or c is closest to p=a+b-c.
+ * ( this is taken from ../intel/filter_sse2_intrinsics.c )
+ */
+
+#define vsx_declare_common_vars(row_info,row,prev_row,offset) \
+   png_byte i;\
+   png_bytep rp = row + offset;\
+   png_const_bytep pp = prev_row;\
+   size_t unaligned_top = 16 - (((size_t)rp % 16));\
+   size_t istop;\
+   if(unaligned_top == 16)\
+      unaligned_top = 0;\
+   istop = row_info->rowbytes;\
+   if((unaligned_top < istop))\
+      istop -= unaligned_top;\
+   else{\
+      unaligned_top = istop;\
+      istop = 0;\
+   }
+
+void png_read_filter_row_up_vsx(png_row_infop row_info, png_bytep row,
+                                png_const_bytep prev_row)
+{
+   vector unsigned char rp_vec;
+   vector unsigned char pp_vec;
+   vsx_declare_common_vars(row_info,row,prev_row,0)
+
+   /* Altivec operations require 16-byte aligned data
+    * but input can be unaligned. So we calculate
+    * unaligned part as usual.
+    */
+   for (i = 0; i < unaligned_top; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+      rp++;
+   }
+
+   /* Using SIMD while we can */
+   while( istop >= 16 )
+   {
+      rp_vec = vec_ld(0,rp);
+      vec_ld_unaligned(pp_vec,pp);
+
+      rp_vec = vec_add(rp_vec,pp_vec);
+
+      vec_st(rp_vec,0,rp);
+
+      pp += 16;
+      rp += 16;
+      istop -= 16;
+   }
+
+   if(istop > 0)
+   {
+      /* If byte count of row is not divisible by 16
+       * we will process remaining part as usual
+       */
+      for (i = 0; i < istop; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+         rp++;
+      }
+}
+
+}
+
+static const vector unsigned char VSX_LEFTSHIFTED1_4 = {16,16,16,16, 0, 1, 2, 3,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED2_4 = {16,16,16,16,16,16,16,16, 4, 5, 6, 7,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED3_4 = {16,16,16,16,16,16,16,16,16,16,16,16, 8, 9,10,11};
+
+static const vector unsigned char VSX_LEFTSHIFTED1_3 = {16,16,16, 0, 1, 2,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED2_3 = {16,16,16,16,16,16, 3, 4, 5,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED3_3 = {16,16,16,16,16,16,16,16,16, 6, 7, 8,16,16,16,16};
+static const vector unsigned char VSX_LEFTSHIFTED4_3 = {16,16,16,16,16,16,16,16,16,16,16,16, 9,10,11,16};
+
+static const vector unsigned char VSX_NOT_SHIFTED1_4 = {16,16,16,16, 4, 5, 6, 7,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED2_4 = {16,16,16,16,16,16,16,16, 8, 9,10,11,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED3_4 = {16,16,16,16,16,16,16,16,16,16,16,16,12,13,14,15};
+
+static const vector unsigned char VSX_NOT_SHIFTED1_3 = {16,16,16, 3, 4, 5,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED2_3 = {16,16,16,16,16,16, 6, 7, 8,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED3_3 = {16,16,16,16,16,16,16,16,16, 9,10,11,16,16,16,16};
+static const vector unsigned char VSX_NOT_SHIFTED4_3 = {16,16,16,16,16,16,16,16,16,16,16,16,12,13,14,16};
+
+static const vector unsigned char VSX_CHAR_ZERO = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+#ifdef __LITTLE_ENDIAN__
+
+static const vector unsigned char VSX_CHAR_TO_SHORT1_4 = { 4,16, 5,16, 6,16, 7,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT2_4 = { 8,16, 9,16,10,16,11,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT3_4 = {12,16,13,16,14,16,15,16,16,16,16,16,16,16,16,16};
+
+static const vector unsigned char VSX_SHORT_TO_CHAR1_4 = {16,16,16,16, 0, 2, 4, 6,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR2_4 = {16,16,16,16,16,16,16,16, 0, 2, 4, 6,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR3_4 = {16,16,16,16,16,16,16,16,16,16,16,16, 0, 2, 4, 6};
+
+static const vector unsigned char VSX_CHAR_TO_SHORT1_3 = { 3,16, 4,16, 5,16,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT2_3 = { 6,16, 7,16, 8,16,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT3_3 = { 9,16,10,16,11,16,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT4_3 = {12,16,13,16,14,16,16,16,16,16,16,16,16,16,16,16};
+
+static const vector unsigned char VSX_SHORT_TO_CHAR1_3 = {16,16,16, 0, 2, 4,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR2_3 = {16,16,16,16,16,16, 0, 2, 4,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR3_3 = {16,16,16,16,16,16,16,16,16, 0, 2, 4,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR4_3 = {16,16,16,16,16,16,16,16,16,16,16,16, 0, 2, 4,16};
+
+#elif defined(__BIG_ENDIAN__)
+
+static const vector unsigned char VSX_CHAR_TO_SHORT1_4 = {16, 4,16, 5,16, 6,16, 7,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT2_4 = {16, 8,16, 9,16,10,16,11,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT3_4 = {16,12,16,13,16,14,16,15,16,16,16,16,16,16,16,16};
+
+static const vector unsigned char VSX_SHORT_TO_CHAR1_4 = {16,16,16,16, 1, 3, 5, 7,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR2_4 = {16,16,16,16,16,16,16,16, 1, 3, 5, 7,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR3_4 = {16,16,16,16,16,16,16,16,16,16,16,16, 1, 3, 5, 7};
+
+static const vector unsigned char VSX_CHAR_TO_SHORT1_3 = {16, 3,16, 4,16, 5,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT2_3 = {16, 6,16, 7,16, 8,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT3_3 = {16, 9,16,10,16,11,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_CHAR_TO_SHORT4_3 = {16,12,16,13,16,14,16,16,16,16,16,16,16,16,16,16};
+
+static const vector unsigned char VSX_SHORT_TO_CHAR1_3 = {16,16,16, 1, 3, 5,16,16,16,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR2_3 = {16,16,16,16,16,16, 1, 3, 5,16,16,16,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR3_3 = {16,16,16,16,16,16,16,16,16, 1, 3, 5,16,16,16,16};
+static const vector unsigned char VSX_SHORT_TO_CHAR4_3 = {16,16,16,16,16,16,16,16,16,16,16,16, 1, 3, 5,16};
+
+#endif
+
+#define vsx_char_to_short(vec,offset,bpp) (vector unsigned short)vec_perm((vec),VSX_CHAR_ZERO,VSX_CHAR_TO_SHORT##offset##_##bpp)
+#define vsx_short_to_char(vec,offset,bpp) vec_perm(((vector unsigned char)(vec)),VSX_CHAR_ZERO,VSX_SHORT_TO_CHAR##offset##_##bpp)
+
+#ifdef PNG_USE_ABS
+#  define vsx_abs(number) abs(number)
+#else
+#  define vsx_abs(number) (number > 0) ? (number) : -(number)
+#endif
+
+void png_read_filter_row_sub4_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   png_byte bpp = 4;
+
+   vector unsigned char rp_vec;
+   vector unsigned char part_vec;
+
+   vsx_declare_common_vars(row_info,row,prev_row,bpp)
+
+   PNG_UNUSED(pp)
+
+   /* Altivec operations require 16-byte aligned data
+    * but input can be unaligned. So we calculate
+    * unaligned part as usual.
+    */
+   for (i = 0; i < unaligned_top; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+      rp++;
+   }
+
+   /* Using SIMD while we can */
+   while( istop >= 16 )
+   {
+      for(i=0;i < bpp ; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+         rp++;
+      }
+      rp -= bpp;
+
+      rp_vec = vec_ld(0,rp);
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_4);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_4);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_4);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      vec_st(rp_vec,0,rp);
+
+      rp += 16;
+      istop -= 16;
+   }
+
+   if(istop > 0)
+      for (i = 0; i < istop % 16; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*(rp - bpp))) & 0xff);
+         rp++;
+      }
+
+}
+
+void png_read_filter_row_sub3_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   png_byte bpp = 3;
+
+   vector unsigned char rp_vec;
+   vector unsigned char part_vec;
+
+   vsx_declare_common_vars(row_info,row,prev_row,bpp)
+
+   PNG_UNUSED(pp)
+
+   /* Altivec operations require 16-byte aligned data
+    * but input can be unaligned. So we calculate
+    * unaligned part as usual.
+    */
+   for (i = 0; i < unaligned_top; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+      rp++;
+   }
+
+   /* Using SIMD while we can */
+   while( istop >= 16 )
+   {
+      for(i=0;i < bpp ; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+         rp++;
+      }
+      rp -= bpp;
+
+      rp_vec = vec_ld(0,rp);
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_3);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_3);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_3);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED4_3);
+      rp_vec = vec_add(rp_vec,part_vec);
+
+      vec_st(rp_vec,0,rp);
+      rp += 15;
+      istop -= 16;
+
+      /* Since 16 % bpp = 16 % 3 = 1, last element of array must
+       * be proceeded manually
+       */
+      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+      rp++;
+   }
+
+   if(istop > 0)
+      for (i = 0; i < istop % 16; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+         rp++;
+      }
+}
+
+void png_read_filter_row_avg4_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   png_byte bpp = 4;
+
+   vector unsigned char rp_vec;
+   vector unsigned char pp_vec;
+   vector unsigned char pp_part_vec;
+   vector unsigned char rp_part_vec;
+   vector unsigned char avg_vec;
+
+   vsx_declare_common_vars(row_info,row,prev_row,bpp)
+   rp -= bpp;
+   if(istop >= bpp)
+      istop -= bpp;
+
+   for (i = 0; i < bpp; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) +
+         ((int)(*pp++) / 2 )) & 0xff);
+
+      rp++;
+   }
+
+   /* Altivec operations require 16-byte aligned data
+    * but input can be unaligned. So we calculate
+    * unaligned part as usual.
+    */
+   for (i = 0; i < unaligned_top; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) +
+         (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+      rp++;
+   }
+
+   /* Using SIMD while we can */
+   while( istop >= 16 )
+   {
+      for(i=0;i < bpp ; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) +
+            (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+         rp++;
+      }
+      rp -= bpp;
+      pp -= bpp;
+
+      vec_ld_unaligned(pp_vec,pp);
+      rp_vec = vec_ld(0,rp);
+
+      rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_4);
+      pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED1_4);
+      avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+      avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+      rp_vec = vec_add(rp_vec,avg_vec);
+
+      rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_4);
+      pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED2_4);
+      avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+      avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+      rp_vec = vec_add(rp_vec,avg_vec);
+
+      rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_4);
+      pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED3_4);
+      avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+      avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+      rp_vec = vec_add(rp_vec,avg_vec);
+
+      vec_st(rp_vec,0,rp);
+
+      rp += 16;
+      pp += 16;
+      istop -= 16;
+   }
+
+   if(istop  > 0)
+      for (i = 0; i < istop % 16; i++)
+      {
+         *rp = (png_byte)(((int)(*rp) +
+            (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+         rp++;
+      }
+}
+
+void png_read_filter_row_avg3_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+  png_byte bpp = 3;
+
+  vector unsigned char rp_vec;
+  vector unsigned char pp_vec;
+  vector unsigned char pp_part_vec;
+  vector unsigned char rp_part_vec;
+  vector unsigned char avg_vec;
+
+  vsx_declare_common_vars(row_info,row,prev_row,bpp)
+  rp -= bpp;
+  if(istop >= bpp)
+     istop -= bpp;
+
+  for (i = 0; i < bpp; i++)
+  {
+     *rp = (png_byte)(((int)(*rp) +
+        ((int)(*pp++) / 2 )) & 0xff);
+
+     rp++;
+  }
+
+  /* Altivec operations require 16-byte aligned data
+   * but input can be unaligned. So we calculate
+   * unaligned part as usual.
+   */
+  for (i = 0; i < unaligned_top; i++)
+  {
+     *rp = (png_byte)(((int)(*rp) +
+        (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+     rp++;
+  }
+
+  /* Using SIMD while we can */
+  while( istop >= 16 )
+  {
+     for(i=0;i < bpp ; i++)
+     {
+        *rp = (png_byte)(((int)(*rp) +
+           (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+        rp++;
+     }
+     rp -= bpp;
+     pp -= bpp;
+
+     vec_ld_unaligned(pp_vec,pp);
+     rp_vec = vec_ld(0,rp);
+
+     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED1_3);
+     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED1_3);
+     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+     rp_vec = vec_add(rp_vec,avg_vec);
+
+     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED2_3);
+     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED2_3);
+     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+     rp_vec = vec_add(rp_vec,avg_vec);
+
+     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED3_3);
+     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED3_3);
+     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+     rp_vec = vec_add(rp_vec,avg_vec);
+
+     rp_part_vec = vec_perm(rp_vec,VSX_CHAR_ZERO,VSX_LEFTSHIFTED4_3);
+     pp_part_vec = vec_perm(pp_vec,VSX_CHAR_ZERO,VSX_NOT_SHIFTED4_3);
+     avg_vec = vec_avg(rp_part_vec,pp_part_vec);
+     avg_vec = vec_sub(avg_vec, vec_and(vec_xor(rp_part_vec,pp_part_vec),vec_splat_u8(1)));
+     rp_vec = vec_add(rp_vec,avg_vec);
+
+     vec_st(rp_vec,0,rp);
+
+     rp += 15;
+     pp += 15;
+     istop -= 16;
+
+     /* Since 16 % bpp = 16 % 3 = 1, last element of array must
+      * be proceeded manually
+      */
+     *rp = (png_byte)(((int)(*rp) +
+        (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+     rp++;
+  }
+
+  if(istop  > 0)
+     for (i = 0; i < istop % 16; i++)
+     {
+        *rp = (png_byte)(((int)(*rp) +
+           (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+        rp++;
+     }
+}
+
+/* Bytewise c ? t : e. */
+#define if_then_else(c,t,e) vec_sel(e,t,c)
+
+#define vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp) {\
+      c = *(pp - bpp);\
+      a = *(rp - bpp);\
+      b = *pp++;\
+      p = b - c;\
+      pc = a - c;\
+      pa = vsx_abs(p);\
+      pb = vsx_abs(pc);\
+      pc = vsx_abs(p + pc);\
+      if (pb < pa) pa = pb, a = b;\
+      if (pc < pa) a = c;\
+      a += *rp;\
+      *rp++ = (png_byte)a;\
+      }
+
+void png_read_filter_row_paeth4_vsx(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+   png_byte bpp = 4;
+
+   int a, b, c, pa, pb, pc, p;
+   vector unsigned char rp_vec;
+   vector unsigned char pp_vec;
+   vector unsigned short a_vec,b_vec,c_vec,nearest_vec;
+   vector signed short pa_vec,pb_vec,pc_vec,smallest_vec;
+
+   vsx_declare_common_vars(row_info,row,prev_row,bpp)
+   rp -= bpp;
+   if(istop >= bpp)
+      istop -= bpp;
+
+   /* Process the first pixel in the row completely (this is the same as 'up'
+    * because there is only one candidate predictor for the first row).
+    */
+   for(i = 0; i < bpp ; i++)
+   {
+      *rp = (png_byte)( *rp + *pp);
+      rp++;
+      pp++;
+   }
+
+   for(i = 0; i < unaligned_top ; i++)
+   {
+      vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+   }
+
+   while( istop >= 16)
+   {
+      for(i = 0; i < bpp ; i++)
+      {
+         vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+      }
+
+      rp -= bpp;
+      pp -= bpp;
+      rp_vec = vec_ld(0,rp);
+      vec_ld_unaligned(pp_vec,pp);
+
+      a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_4),1,4);
+      b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED1_4),1,4);
+      c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_4),1,4);
+      pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+      pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+      pc_vec = vec_add(pa_vec,pb_vec);
+      pa_vec = vec_abs(pa_vec);
+      pb_vec = vec_abs(pb_vec);
+      pc_vec = vec_abs(pc_vec);
+      smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+      nearest_vec =  if_then_else(
+            vec_cmpeq(pa_vec,smallest_vec),
+            a_vec,
+            if_then_else(
+              vec_cmpeq(pb_vec,smallest_vec),
+              b_vec,
+              c_vec
+              )
+            );
+      rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,1,4)));
+
+      a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_4),2,4);
+      b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED2_4),2,4);
+      c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_4),2,4);
+      pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+      pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+      pc_vec = vec_add(pa_vec,pb_vec);
+      pa_vec = vec_abs(pa_vec);
+      pb_vec = vec_abs(pb_vec);
+      pc_vec = vec_abs(pc_vec);
+      smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+      nearest_vec =  if_then_else(
+            vec_cmpeq(pa_vec,smallest_vec),
+            a_vec,
+            if_then_else(
+              vec_cmpeq(pb_vec,smallest_vec),
+              b_vec,
+              c_vec
+              )
+            );
+      rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,2,4)));
+
+      a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_4),3,4);
+      b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED3_4),3,4);
+      c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_4),3,4);
+      pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+      pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+      pc_vec = vec_add(pa_vec,pb_vec);
+      pa_vec = vec_abs(pa_vec);
+      pb_vec = vec_abs(pb_vec);
+      pc_vec = vec_abs(pc_vec);
+      smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+      nearest_vec =  if_then_else(
+            vec_cmpeq(pa_vec,smallest_vec),
+            a_vec,
+            if_then_else(
+              vec_cmpeq(pb_vec,smallest_vec),
+              b_vec,
+              c_vec
+              )
+            );
+      rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,3,4)));
+
+      vec_st(rp_vec,0,rp);
+
+      rp += 16;
+      pp += 16;
+      istop -= 16;
+   }
+
+   if(istop > 0)
+      for (i = 0; i < istop % 16; i++)
+      {
+         vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+      }
+}
+
+void png_read_filter_row_paeth3_vsx(png_row_infop row_info, png_bytep row,
+   png_const_bytep prev_row)
+{
+  png_byte bpp = 3;
+
+  int a, b, c, pa, pb, pc, p;
+  vector unsigned char rp_vec;
+  vector unsigned char pp_vec;
+  vector unsigned short a_vec,b_vec,c_vec,nearest_vec;
+  vector signed short pa_vec,pb_vec,pc_vec,smallest_vec;
+
+  vsx_declare_common_vars(row_info,row,prev_row,bpp)
+  rp -= bpp;
+  if(istop >= bpp)
+     istop -= bpp;
+
+  /* Process the first pixel in the row completely (this is the same as 'up'
+   * because there is only one candidate predictor for the first row).
+   */
+  for(i = 0; i < bpp ; i++)
+  {
+     *rp = (png_byte)( *rp + *pp);
+     rp++;
+     pp++;
+  }
+
+  for(i = 0; i < unaligned_top ; i++)
+  {
+     vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+  }
+
+  while( istop >= 16)
+  {
+     for(i = 0; i < bpp ; i++)
+     {
+        vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+     }
+
+     rp -= bpp;
+     pp -= bpp;
+     rp_vec = vec_ld(0,rp);
+     vec_ld_unaligned(pp_vec,pp);
+
+     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_3),1,3);
+     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED1_3),1,3);
+     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED1_3),1,3);
+     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+     pc_vec = vec_add(pa_vec,pb_vec);
+     pa_vec = vec_abs(pa_vec);
+     pb_vec = vec_abs(pb_vec);
+     pc_vec = vec_abs(pc_vec);
+     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+     nearest_vec =  if_then_else(
+           vec_cmpeq(pa_vec,smallest_vec),
+           a_vec,
+           if_then_else(
+             vec_cmpeq(pb_vec,smallest_vec),
+             b_vec,
+             c_vec
+             )
+           );
+     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,1,3)));
+
+     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_3),2,3);
+     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED2_3),2,3);
+     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED2_3),2,3);
+     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+     pc_vec = vec_add(pa_vec,pb_vec);
+     pa_vec = vec_abs(pa_vec);
+     pb_vec = vec_abs(pb_vec);
+     pc_vec = vec_abs(pc_vec);
+     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+     nearest_vec =  if_then_else(
+           vec_cmpeq(pa_vec,smallest_vec),
+           a_vec,
+           if_then_else(
+             vec_cmpeq(pb_vec,smallest_vec),
+             b_vec,
+             c_vec
+             )
+           );
+     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,2,3)));
+
+     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_3),3,3);
+     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED3_3),3,3);
+     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED3_3),3,3);
+     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+     pc_vec = vec_add(pa_vec,pb_vec);
+     pa_vec = vec_abs(pa_vec);
+     pb_vec = vec_abs(pb_vec);
+     pc_vec = vec_abs(pc_vec);
+     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+     nearest_vec =  if_then_else(
+           vec_cmpeq(pa_vec,smallest_vec),
+           a_vec,
+           if_then_else(
+             vec_cmpeq(pb_vec,smallest_vec),
+             b_vec,
+             c_vec
+             )
+           );
+     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,3,3)));
+
+     a_vec = vsx_char_to_short(vec_perm(rp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED4_3),4,3);
+     b_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_NOT_SHIFTED4_3),4,3);
+     c_vec = vsx_char_to_short(vec_perm(pp_vec , VSX_CHAR_ZERO , VSX_LEFTSHIFTED4_3),4,3);
+     pa_vec = (vector signed short) vec_sub(b_vec,c_vec);
+     pb_vec = (vector signed short) vec_sub(a_vec , c_vec);
+     pc_vec = vec_add(pa_vec,pb_vec);
+     pa_vec = vec_abs(pa_vec);
+     pb_vec = vec_abs(pb_vec);
+     pc_vec = vec_abs(pc_vec);
+     smallest_vec = vec_min(pc_vec, vec_min(pa_vec,pb_vec));
+     nearest_vec =  if_then_else(
+           vec_cmpeq(pa_vec,smallest_vec),
+           a_vec,
+           if_then_else(
+             vec_cmpeq(pb_vec,smallest_vec),
+             b_vec,
+             c_vec
+             )
+           );
+     rp_vec = vec_add(rp_vec,(vsx_short_to_char(nearest_vec,4,3)));
+
+     vec_st(rp_vec,0,rp);
+
+     rp += 15;
+     pp += 15;
+     istop -= 16;
+
+     /* Since 16 % bpp = 16 % 3 = 1, last element of array must
+      * be proceeded manually
+      */
+     vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+  }
+
+  if(istop > 0)
+     for (i = 0; i < istop % 16; i++)
+     {
+        vsx_paeth_process(rp,pp,a,b,c,pa,pb,pc,bpp)
+     }
+}
+
+#endif /* PNG_POWERPC_VSX_OPT > 0 */
+#endif /* PNG_POWERPC_VSX_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/powerpc/powerpc_init.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/powerpc/powerpc_init.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/powerpc/powerpc_init.c	(revision 107811)
@@ -0,0 +1,126 @@
+
+/* powerpc_init.c - POWERPC optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2017 Glenn Randers-Pehrson
+ * Written by Vadim Barkov, 2017.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
+ * called.
+ */
+#define _POSIX_SOURCE 1
+
+#include <stdio.h>
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_POWERPC_VSX_OPT > 0
+#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED /* Do run-time checks */
+/* WARNING: it is strongly recommended that you do not build libpng with
+ * run-time checks for CPU features if at all possible.  In the case of the PowerPC
+ * VSX instructions there is no processor-specific way of detecting the
+ * presence of the required support, therefore run-time detection is extremely
+ * OS specific.
+ *
+ * You may set the macro PNG_POWERPC_VSX_FILE to the file name of file containing
+ * a fragment of C source code which defines the png_have_vsx function.  There
+ * are a number of implementations in contrib/powerpc-vsx, but the only one that
+ * has partial support is contrib/powerpc-vsx/linux.c - a generic Linux
+ * implementation which reads /proc/cpufino.
+ */
+#ifndef PNG_POWERPC_VSX_FILE
+#  ifdef __linux__
+#     define  PNG_POWERPC_VSX_FILE "contrib/powerpc-vsx/linux_aux.c"
+#  endif
+#endif
+
+#ifdef PNG_POWERPC_VSX_FILE
+
+#include <signal.h> /* for sig_atomic_t */
+static int png_have_vsx(png_structp png_ptr);
+#include PNG_POWERPC_VSX_FILE
+
+#else  /* PNG_POWERPC_VSX_FILE */
+#  error "PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks"
+#endif /* PNG_POWERPC_VSX_FILE */
+#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
+
+void
+png_init_filter_functions_vsx(png_structp pp, unsigned int bpp)
+{
+   /* The switch statement is compiled in for POWERPC_VSX_API, the call to
+    * png_have_vsx is compiled in for POWERPC_VSX_CHECK. If both are defined
+    * the check is only performed if the API has not set the PowerPC option on
+    * or off explicitly. In this case the check controls what happens.
+    */
+
+#ifdef PNG_POWERPC_VSX_API_SUPPORTED
+   switch ((pp->options >> PNG_POWERPC_VSX) & 3)
+   {
+      case PNG_OPTION_UNSET:
+         /* Allow the run-time check to execute if it has been enabled -
+          * thus both API and CHECK can be turned on.  If it isn't supported
+          * this case will fall through to the 'default' below, which just
+          * returns.
+          */
+#endif /* PNG_POWERPC_VSX_API_SUPPORTED */
+#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
+         {
+            static volatile sig_atomic_t no_vsx = -1; /* not checked */
+
+            if (no_vsx < 0)
+               no_vsx = !png_have_vsx(pp);
+
+            if (no_vsx)
+               return;
+         }
+#ifdef PNG_POWERPC_VSX_API_SUPPORTED
+         break;
+#endif
+#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
+
+#ifdef PNG_POWERPC_VSX_API_SUPPORTED
+      default: /* OFF or INVALID */
+         return;
+
+      case PNG_OPTION_ON:
+         /* Option turned on */
+         break;
+   }
+#endif
+
+   /* IMPORTANT: any new internal functions used here must be declared using
+    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
+    * 'prefix' option to configure works:
+    *
+    *    ./configure --with-libpng-prefix=foobar_
+    *
+    * Verify you have got this right by running the above command, doing a build
+    * and examining pngprefix.h; it must contain a #define for every external
+    * function you add.  (Notice that this happens automatically for the
+    * initialization function.)
+    */
+   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_vsx;
+
+   if (bpp == 3)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_vsx;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_vsx;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_vsx;
+   }
+
+   else if (bpp == 4)
+   {
+      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_vsx;
+      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_vsx;
+      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_vsx;
+   }
+}
+#endif /* PNG_POWERPC_VSX_OPT > 0 */
+#endif /* READ */
Index: /trunk/src/libs/libpng-1.6.45/projects/owatcom/libpng.tgt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/owatcom/libpng.tgt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/owatcom/libpng.tgt	(revision 107811)
@@ -0,0 +1,383 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+3
+LIB
+3
+WString
+5
+n_2sn
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+0
+6
+MItem
+10
+libpng.lib
+7
+WString
+3
+LIB
+8
+WVList
+0
+9
+WVList
+1
+10
+ActionStates
+11
+WString
+5
+&Make
+12
+WVList
+0
+-1
+1
+1
+0
+13
+WPickList
+16
+14
+MItem
+3
+*.c
+15
+WString
+4
+COBJ
+16
+WVList
+2
+17
+MVState
+18
+WString
+3
+WCC
+19
+WString
+25
+n????Include directories:
+1
+20
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+21
+MVState
+22
+WString
+3
+WCC
+23
+WString
+25
+n????Include directories:
+0
+24
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+25
+WVList
+1
+26
+ActionStates
+27
+WString
+5
+&Make
+28
+WVList
+0
+-1
+1
+1
+0
+29
+MItem
+11
+..\..\png.c
+30
+WString
+4
+COBJ
+31
+WVList
+0
+32
+WVList
+0
+14
+1
+1
+0
+33
+MItem
+16
+..\..\pngerror.c
+34
+WString
+4
+COBJ
+35
+WVList
+0
+36
+WVList
+0
+14
+1
+1
+0
+37
+MItem
+14
+..\..\pngget.c
+38
+WString
+4
+COBJ
+39
+WVList
+0
+40
+WVList
+0
+14
+1
+1
+0
+41
+MItem
+14
+..\..\pngmem.c
+42
+WString
+4
+COBJ
+43
+WVList
+0
+44
+WVList
+0
+14
+1
+1
+0
+45
+MItem
+16
+..\..\pngpread.c
+46
+WString
+4
+COBJ
+47
+WVList
+0
+48
+WVList
+0
+14
+1
+1
+0
+49
+MItem
+15
+..\..\pngread.c
+50
+WString
+4
+COBJ
+51
+WVList
+0
+52
+WVList
+0
+14
+1
+1
+0
+53
+MItem
+14
+..\..\pngrio.c
+54
+WString
+4
+COBJ
+55
+WVList
+0
+56
+WVList
+0
+14
+1
+1
+0
+57
+MItem
+16
+..\..\pngrtran.c
+58
+WString
+4
+COBJ
+59
+WVList
+0
+60
+WVList
+0
+14
+1
+1
+0
+61
+MItem
+16
+..\..\pngrutil.c
+62
+WString
+4
+COBJ
+63
+WVList
+0
+64
+WVList
+0
+14
+1
+1
+0
+65
+MItem
+14
+..\..\pngset.c
+66
+WString
+4
+COBJ
+67
+WVList
+0
+68
+WVList
+0
+14
+1
+1
+0
+69
+MItem
+16
+..\..\pngtrans.c
+70
+WString
+4
+COBJ
+71
+WVList
+0
+72
+WVList
+0
+14
+1
+1
+0
+73
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+14
+..\..\pngwio.c
+74
+WString
+4
+COBJ
+75
+WVList
+0
+76
+WVList
+0
+14
+1
+1
+0
+77
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+16
+..\..\pngwrite.c
+78
+WString
+4
+COBJ
+79
+WVList
+0
+80
+WVList
+0
+14
+1
+1
+0
+81
+MItem
+16
+..\..\pngwtran.c
+82
+WString
+4
+COBJ
+83
+WVList
+0
+84
+WVList
+0
+14
+1
+1
+0
+85
+MItem
+16
+..\..\pngwutil.c
+86
+WString
+4
+COBJ
+87
+WVList
+0
+88
+WVList
+0
+14
+1
+1
+0
Index: /trunk/src/libs/libpng-1.6.45/projects/owatcom/libpng.wpj
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/owatcom/libpng.wpj	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/owatcom/libpng.wpj	(revision 107811)
@@ -0,0 +1,112 @@
+40
+projectIdent
+0
+VpeMain
+1
+WRect
+256
+0
+8960
+9294
+2
+MProject
+3
+MCommand
+322
+# Locations of zlib and (if required) awk (change as required:)
+set zlib=..\..\..\zlib
+set awk=
+#
+@if not exist pngconfig.dfa $(MAKE) $(__MAKEOPTS__) -f pngconfig.mak defaults
+@if exist config.inf type config.inf
+@echo Checking for the libpng configuration file pnglibconf.h
+$(MAKE) $(__MAKEOPTS__) -f pngconfig.mak
+4
+MCommand
+19
+@type pngconfig.inf
+4
+5
+WFileName
+10
+libpng.tgt
+6
+WFileName
+11
+pngtest.tgt
+7
+WFileName
+12
+pngvalid.tgt
+8
+WFileName
+12
+pngstest.tgt
+9
+WVList
+4
+10
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+11
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+0
+5638
+4174
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+14
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+1280
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+0
+0
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+0
+1
+16
+VComponent
+17
+WRect
+524
+497
+5638
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+0
+0
+18
+WFileName
+12
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+0
+1
+19
+VComponent
+20
+WRect
+2054
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+5674
+4232
+0
+0
+21
+WFileName
+12
+pngstest.tgt
+0
+1
+19
Index: /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngconfig.mak
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngconfig.mak	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngconfig.mak	(revision 107811)
@@ -0,0 +1,160 @@
+# This is an OpenWatcom make file which builds pnglibconf.h - the libpng
+# configuration header.  You can ignore this file if you don't need to
+# configure libpng; a default configuration will be built.
+#
+# For more information build libpng.wpj under the IDE and then read the
+# generated files:
+#
+#    config.inf: Basic configuration information for a standard build.
+#    pngconfig.dfa: Advanced configuration for non-standard libpng builds.
+#
+DELETE=rm -f
+ECHO=echo
+COPY=copy
+#
+# If your configuration needs to test compiler flags when building
+# pnglibconf.h you may need to override the following on the wmake command
+# line:
+CFLAGS=
+CC=wcl386
+CPP=$(CC) -pw0
+#
+# Read awk from the environment if set, else it can be set on the command
+# line (the default approach is to set the %awk% environment variable in the
+# IDE libpng.wpj 'before' rule - this setting is local.)
+!ifdef %awk
+AWK=$(%awk)
+!endif
+#
+# pnglibconf.h must exist in the source directory, this is the final rule
+# which copies the local built version (and this is the default target for
+# this makefile.)
+..\..\pnglibconf.h: pnglibconf.h
+ $(COPY) pnglibconf.h $@
+
+!ifdef AWK
+# CPPFLAGS should contain the options to control the result,
+# but DEFS and CFLAGS are also supported here, override
+# as appropriate
+DFNFLAGS = $(DEFS) $(CPPFLAGS) $(CFLAGS)
+
+pnglibconf.h: pnglibconf.dfn
+ $(DELETE) $@ dfn.c dfn1.out dfn2.out
+ $(ECHO) $#include "pnglibconf.dfn" >dfn.c
+ $(CPP) $(DFNFLAGS) dfn.c >dfn1.out
+ $(AWK) -f << dfn1.out >dfn2.out
+/^.*PNG_DEFN_MAGIC-.*-PNG_DEFN_END.*$$/{
+ sub(/^.*PNG_DEFN_MAGIC-/, "")
+ sub(/ *-PNG_DEFN_END.*$$/, "")
+ gsub(/ *@@@ */, "")
+ print
+}
+<<
+ $(COPY) dfn2.out $@
+ @type << >pngconfig.inf
+This is a locally configurable build of libpng.lib; for configuration
+instructions consult and edit projects/openwatcom/pngconfig.dfa
+<<
+ $(DELETE) dfn.c dfn1.out dfn2.out
+
+pnglibconf.dfn: ..\..\scripts\pnglibconf.dfa ..\..\scripts\options.awk pngconfig.dfa ..\..\pngconf.h
+ $(DELETE) $@ dfn1.out dfn2.out
+ $(AWK) -f ..\..\scripts\options.awk out=dfn1.out version=search ..\..\pngconf.h ..\..\scripts\pnglibconf.dfa pngconfig.dfa $(DFA_XTRA) 1>&2
+ $(AWK) -f ..\..\scripts\options.awk out=dfn2.out dfn1.out 1>&2
+ $(COPY) dfn2.out $@
+ $(DELETE) dfn1.out dfn2.out
+
+!else
+# The following lines are used to copy scripts\pnglibconf.h.prebuilt and make
+# the required change to the calling convention.
+#
+# By default libpng is built to use the __cdecl calling convention on
+# Windows.  This gives compatibility with MSVC and GCC.  Unfortunately it
+# does not work with OpenWatcom because OpenWatcom implements longjmp using
+# the __watcall convention (compared with both MSVC and GCC which use __cdecl
+# for library functions.)
+#
+# Thus the default must be changed to build on OpenWatcom and, once changed,
+# the result will not be compatible with applications built using other
+# compilers (in fact attempts to build will fail at compile time.)
+#
+pnglibconf.h: ..\..\scripts\pnglibconf.h.prebuilt .existsonly
+ @$(ECHO) .
+ @$(ECHO) .
+ @$(ECHO) $$(AWK) NOT AVAILABLE: COPYING scripts\pnglibconf.h.prebuilt
+ @$(ECHO) .
+ @$(ECHO) .
+ vi -q -k ":1,$$s/PNG_API_RULE 0$$/PNG_API_RULE 2/\n:w! $@\n:q!\n" ..\..\scripts\pnglibconf.h.prebuilt
+ @$(ECHO) .
+ @$(ECHO) .
+ @$(ECHO) YOU HAVE A DEFAULT CONFIGURATION BECAUSE YOU DO NOT HAVE AWK!
+ @$(ECHO) .
+ @$(ECHO) .
+ @type << >pngconfig.inf
+This is the default configuration of libpng.lib, if you wish to
+change the configuration please consult the instructions in
+projects/owatcom/pngconfig.dfa.
+<<
+
+!endif
+
+# Make the default files
+defaults: .symbolic
+ @$(COPY) << config.inf
+$# The libpng project is incompletely configured.  To complete configuration
+$# please complete the following steps:
+$#
+$#   1) Edit the 'before' rule of libpng.wpj (from the IDE) to define the
+$#      locations of the zlib include file zlib.h and the built zlib library,
+$#      zlib.lib.
+$#
+$#   2) If you want to change libpng to a non-standard configuration also
+$#      change the definition of 'awk' in the before rule to the name of your
+$#      awk command.  For more instructions on configuration read
+$#      pngconfig.dfa.
+$#
+$#   3) Delete this file (config.inf).
+<<
+ @$(COPY) << pngconfig.dfa
+$# pngconfig.dfa: this file contains configuration options for libpng.
+$# If empty the standard configuration will be built.  For this file to be
+$# used a working version of the program 'awk' is required and the program
+$# must be identified in the 'before' rule of the project.
+$#
+$# If you don't already have 'awk', or the version of awk you have seems not
+$# to work, download Brian Kernighan's awk (Brian Kernighan is the author of
+$# awk.)  You can find source code and a built executable (called awk95.exe)
+$# here:
+$#
+$#     https://www.cs.princeton.edu/~bwk/btl.mirror/
+$#
+$# The executable works just fine.
+$#
+$# If build issues errors after a change to pngconfig.dfa you have entered
+$# inconsistent feature requests, or even malformed requests, in
+$# pngconfig.dfa.  The error messages from awk should be comprehensible, but
+$# if not simply go back to the start (nothing but comments in this file) and
+$# enter configuration lines one by one until one produces an error.  (Or, of
+$# course, do the standard binary chop.)
+$#
+$# You need to rebuild everything after a change to pnglibconf.dfa - i.e. you
+$# must do Actions/Mark All Targets for Remake.  This is because the compiler
+$# generated dependency information (as of OpenWatcom 1.9) does not record the
+$# dependency on pnglibconf.h correctly.
+$#
+$# If awk isn't set then this file is bypassed.  If you just want the standard
+$# configuration it is automatically produced from the distributed version
+$# (scripts\pnglibconf.h.prebuilt) by editing PNG_API_RULE to 2 (to force use
+$# of the OpenWatcom library calling convention.)
+$#
+<<
+
+clean:: .symbolic
+ $(DELETE) ..\..\pnglibconf.h pnglibconf.* dfn.c *.out pngconfig.inf
+ $(DELETE) *.obj *.mbr *.sym *.err *.pch libpng.mk
+ $(DELETE) libpng.lib libpng.lbr libpng.lb1 libpng.cbr libpng.mk1
+ $(DELETE) pngtest.exe pngtest.map pngtest.lk1 pngtest.mk1
+ $(DELETE) pngvalid.exe pngvalid.map pngvalid.lk1 pngvalid.mk1
+
+distclean:: clean .symbolic
+ $(DELETE) zlib.inf awk.inf config.inf pngconfig.dfa
Index: /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngstest.tgt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngstest.tgt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngstest.tgt	(revision 107811)
@@ -0,0 +1,219 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+4
+NEXE
+3
+WString
+5
+nc2en
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+1118
+pngstest --strict --log ../../contrib/pngsuite/basn0g01.png ../../contrib/pngsuite/basn0g02.png ../../contrib/pngsuite/basn0g04.png ../../contrib/pngsuite/basn0g08.png ../../contrib/pngsuite/basn0g16.png ../../contrib/pngsuite/basn2c08.png ../../contrib/pngsuite/basn2c16.png ../../contrib/pngsuite/basn3p01.png ../../contrib/pngsuite/basn3p02.png ../../contrib/pngsuite/basn3p04.png ../../contrib/pngsuite/basn3p08.png ../../contrib/pngsuite/basn4a08.png ../../contrib/pngsuite/basn4a16.png ../../contrib/pngsuite/basn6a08.png ../../contrib/pngsuite/basn6a16.png ../../contrib/pngsuite/ftbbn0g04.png ../../contrib/pngsuite/ftbbn0g01.png ../../contrib/pngsuite/ftbbn0g02.png ../../contrib/pngsuite/ftbbn2c16.png ../../contrib/pngsuite/ftbbn3p08.png ../../contrib/pngsuite/ftbgn2c16.png ../../contrib/pngsuite/ftbgn3p08.png ../../contrib/pngsuite/ftbrn2c08.png ../../contrib/pngsuite/ftbwn0g16.png ../../contrib/pngsuite/ftbwn3p08.png ../../contrib/pngsuite/ftbyn3p08.png ../../contrib/pngsuite/ftp0n0g08.png ../../contrib/pngsuite/ftp0n2c08.png ../../contrib/pngsuite/ftp0n3p08.png ../../contrib/pngsuite/ftp1n3p08.png
+6
+MItem
+12
+pngstest.exe
+7
+WString
+4
+NEXE
+8
+WVList
+6
+9
+MVState
+10
+WString
+7
+WINLINK
+11
+WString
+11
+?????Stack:
+1
+12
+WString
+4
+768k
+0
+13
+MVState
+14
+WString
+7
+WINLINK
+15
+WString
+28
+?????Library directories(;):
+1
+16
+WString
+8
+$(%zlib)
+0
+17
+MVState
+18
+WString
+7
+WINLINK
+19
+WString
+18
+?????Libraries(,):
+1
+20
+WString
+19
+libpng.lib zlib.lib
+0
+21
+MVState
+22
+WString
+7
+WINLINK
+23
+WString
+11
+?????Stack:
+0
+24
+WString
+4
+768k
+0
+25
+MVState
+26
+WString
+7
+WINLINK
+27
+WString
+28
+?????Library directories(;):
+0
+28
+WString
+8
+$(%zlib)
+0
+29
+MVState
+30
+WString
+7
+WINLINK
+31
+WString
+18
+?????Libraries(,):
+0
+32
+WString
+19
+libpng.lib zlib.lib
+0
+33
+WVList
+1
+34
+ActionStates
+35
+WString
+4
+&Run
+36
+WVList
+0
+-1
+1
+1
+0
+37
+WPickList
+2
+38
+MItem
+3
+*.c
+39
+WString
+4
+COBJ
+40
+WVList
+2
+41
+MVState
+42
+WString
+3
+WCC
+43
+WString
+25
+n????Include directories:
+1
+44
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+45
+MVState
+46
+WString
+3
+WCC
+47
+WString
+25
+n????Include directories:
+0
+48
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+49
+WVList
+0
+-1
+1
+1
+0
+50
+MItem
+33
+..\..\contrib\libtests\pngstest.c
+51
+WString
+4
+COBJ
+52
+WVList
+0
+53
+WVList
+0
+38
+1
+1
+0
Index: /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngtest.tgt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngtest.tgt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngtest.tgt	(revision 107811)
@@ -0,0 +1,179 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+4
+NEXE
+3
+WString
+5
+nc2en
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+34
+cd ..\..
+projects\owatcom\pngtest
+6
+MItem
+11
+pngtest.exe
+7
+WString
+4
+NEXE
+8
+WVList
+4
+9
+MVState
+10
+WString
+7
+WINLINK
+11
+WString
+28
+?????Library directories(;):
+1
+12
+WString
+8
+$(%zlib)
+0
+13
+MVState
+14
+WString
+7
+WINLINK
+15
+WString
+18
+?????Libraries(,):
+1
+16
+WString
+19
+libpng.lib zlib.lib
+0
+17
+MVState
+18
+WString
+7
+WINLINK
+19
+WString
+28
+?????Library directories(;):
+0
+20
+WString
+8
+$(%zlib)
+0
+21
+MVState
+22
+WString
+7
+WINLINK
+23
+WString
+18
+?????Libraries(,):
+0
+24
+WString
+19
+libpng.lib zlib.lib
+0
+25
+WVList
+0
+-1
+1
+1
+0
+26
+WPickList
+2
+27
+MItem
+3
+*.c
+28
+WString
+4
+COBJ
+29
+WVList
+2
+30
+MVState
+31
+WString
+3
+WCC
+32
+WString
+25
+n????Include directories:
+1
+33
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+34
+MVState
+35
+WString
+3
+WCC
+36
+WString
+25
+n????Include directories:
+0
+37
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+38
+WVList
+0
+-1
+1
+1
+0
+39
+MItem
+15
+..\..\pngtest.c
+40
+WString
+4
+COBJ
+41
+WVList
+0
+42
+WVList
+0
+27
+1
+1
+0
Index: /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngvalid.tgt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngvalid.tgt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/owatcom/pngvalid.tgt	(revision 107811)
@@ -0,0 +1,210 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+4
+NEXE
+3
+WString
+5
+nc2en
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+8
+pngvalid
+6
+MItem
+12
+pngvalid.exe
+7
+WString
+4
+NEXE
+8
+WVList
+6
+9
+MVState
+10
+WString
+7
+WINLINK
+11
+WString
+11
+?????Stack:
+1
+12
+WString
+4
+768k
+0
+13
+MVState
+14
+WString
+7
+WINLINK
+15
+WString
+28
+?????Library directories(;):
+1
+16
+WString
+8
+$(%zlib)
+0
+17
+MVState
+18
+WString
+7
+WINLINK
+19
+WString
+18
+?????Libraries(,):
+1
+20
+WString
+19
+libpng.lib zlib.lib
+0
+21
+MVState
+22
+WString
+7
+WINLINK
+23
+WString
+11
+?????Stack:
+0
+24
+WString
+4
+768k
+0
+25
+MVState
+26
+WString
+7
+WINLINK
+27
+WString
+28
+?????Library directories(;):
+0
+28
+WString
+8
+$(%zlib)
+0
+29
+MVState
+30
+WString
+7
+WINLINK
+31
+WString
+18
+?????Libraries(,):
+0
+32
+WString
+19
+libpng.lib zlib.lib
+0
+33
+WVList
+0
+-1
+1
+1
+0
+34
+WPickList
+2
+35
+MItem
+3
+*.c
+36
+WString
+4
+COBJ
+37
+WVList
+2
+38
+MVState
+39
+WString
+3
+WCC
+40
+WString
+25
+n????Include directories:
+1
+41
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+42
+MVState
+43
+WString
+3
+WCC
+44
+WString
+25
+n????Include directories:
+0
+45
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+46
+WVList
+0
+-1
+1
+1
+0
+47
+MItem
+33
+..\..\contrib\libtests\pngvalid.c
+48
+WString
+4
+COBJ
+49
+WVList
+0
+50
+WVList
+0
+35
+1
+1
+0
Index: /trunk/src/libs/libpng-1.6.45/projects/visualc71/PRJ0041.mak
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/visualc71/PRJ0041.mak	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/visualc71/PRJ0041.mak	(revision 107811)
@@ -0,0 +1,21 @@
+# Prevent "Cannot find missing dependency..." warnings while compiling
+# pngwin.rc (PRJ0041).
+
+all: $(IntDir)\alloc.h \
+	 $(IntDir)\fp.h \
+	 $(IntDir)\m68881.h \
+	 $(IntDir)\mem.h \
+	 $(IntDir)\pngusr.h \
+	 $(IntDir)\strings.h \
+	 $(IntDir)\unistd.h \
+	 $(IntDir)\unixio.h
+
+$(IntDir)\alloc.h \
+$(IntDir)\fp.h \
+$(IntDir)\m68881.h \
+$(IntDir)\mem.h \
+$(IntDir)\pngusr.h \
+$(IntDir)\strings.h \
+$(IntDir)\unistd.h \
+$(IntDir)\unixio.h:
+	@!echo.>$@
Index: /trunk/src/libs/libpng-1.6.45/projects/visualc71/README.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/visualc71/README.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/visualc71/README.txt	(revision 107811)
@@ -0,0 +1,58 @@
+Microsoft Developer Studio Project File, Format Version 7.10 for libpng.
+
+Copyright (C) 2004 Simon-Pierre Cadieux.
+
+This code is released under the libpng license.
+For conditions of distribution and use, see copyright notice in png.h
+
+NOTE: This project will be removed from libpng-1.5.0.  It has
+been replaced with the "vstudio" project.
+
+Assumptions:
+* The libpng source files are in ..\..
+* The zlib source files are in ..\..\..\zlib
+* The zlib project file is in . /* Warning: This is until the zlib project
+  files get integrated into the next zlib release. The final zlib project
+  directory will then be ..\..\..\zlib\projects\visualc71. */
+
+To use:
+
+1) On the main menu, select "File | Open Solution".
+   Open "libpng.sln".
+
+2) Display the Solution Explorer view (Ctrl+Alt+L)
+
+3) Set one of the project as the StartUp project. If you just want to build the
+   binaries set "libpng" as the startup project (Select "libpng" tree view
+   item + Project | Set as StartUp project). If you want to build and test the
+   binaries set it to "pngtest" (Select "pngtest" tree view item +
+   Project | Set as StartUp project)
+
+4) Select "Build | Configuration Manager...".
+   Choose the configuration you wish to build.
+
+5) Select "Build | Clean Solution".
+
+6) Select "Build | Build Solution (Ctrl-Shift-B)"
+
+This project builds the libpng binaries as follows:
+
+* Win32_DLL_Release\libpng16.dll      DLL build
+* Win32_DLL_Debug\libpng16d.dll       DLL build (debug version)
+* Win32_DLL_VB\libpng16vb.dll         DLL build for Visual Basic, using stdcall
+* Win32_LIB_Release\libpng.lib        static build
+* Win32_LIB_Debug\libpngd.lib         static build (debug version)
+
+Notes:
+
+If you change anything in the source files, or select different compiler
+settings, please change the DLL name to something different than any of
+the above names. Also, make sure that in your "pngusr.h" you define
+PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX according to the
+instructions provided in "pngconf.h".
+
+All DLLs built by this project use the Microsoft dynamic C runtime library
+MSVCR71.DLL (MSVCR71D.DLL for debug versions).  If you distribute any of the
+above mentioned libraries you may have to include this DLL in your package.
+For a list of files that are redistributable in Visual Studio see
+$(VCINSTALLDIR)\redist.txt.
Index: /trunk/src/libs/libpng-1.6.45/projects/visualc71/README_zlib.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/visualc71/README_zlib.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/visualc71/README_zlib.txt	(revision 107811)
@@ -0,0 +1,44 @@
+/* WARNING: This file was put in the LibPNG distribution for convenience only.
+            It is expected to be part of the next zlib release under
+            "projects\visualc71\README.txt." */
+
+Microsoft Developer Studio Project File, Format Version 7.10 for zlib.
+
+Copyright (C) 2004 Simon-Pierre Cadieux.
+Copyright (C) 2004 Cosmin Truta.
+
+This code is released under the libpng license.
+For conditions of distribution and use, see copyright notice in zlib.h.
+
+NOTE: This project will be removed from libpng-1.5.0.  It has
+been replaced with the "vstudio" project.
+
+To use:
+
+1) On the main menu, select "File | Open Solution".
+   Open "zlib.sln".
+
+2) Display the Solution Explorer view (Ctrl+Alt+L)
+
+3) Set one of the project as the StartUp project. If you just want to build the
+   binaries set "zlib" as the startup project (Select "zlib" tree view item +
+   Project | Set as StartUp project). If you want to build and test the
+   binaries set it to "example" (Select "example" tree view item + Project |
+   Set as StartUp project), If you want to build the minigzip utility set it to
+   "minigzip" (Select "minigzip" tree view item + Project | Set as StartUp
+   project
+
+4) Select "Build | Configuration Manager...".
+   Choose the configuration you wish to build.
+
+5) Select "Build | Clean Solution".
+
+6) Select "Build | Build Solution (Ctrl-Shift-B)"
+
+This project builds the zlib binaries as follows:
+
+* Win32_DLL_Release\zlib1.dll       DLL build
+* Win32_DLL_Debug\zlib1d.dll        DLL build (debug version)
+* Win32_LIB_Release\zlib.lib        static build
+* Win32_LIB_Debug\zlibd.lib         static build (debug version)
+
Index: /trunk/src/libs/libpng-1.6.45/projects/visualc71/libpng.sln
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/visualc71/libpng.sln	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/visualc71/libpng.sln	(revision 107811)
@@ -0,0 +1,60 @@
+Microsoft Visual Studio Solution File, Format Version 8.00
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "libpng", "libpng.vcproj", "{0008960E-E0DD-41A6-8265-00B31DDB4C21}"
+	ProjectSection(ProjectDependencies) = postProject
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0} = {2D4F8105-7D21-454C-9932-B47CAB71A5C0}
+	EndProjectSection
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngtest", "pngtest.vcproj", "{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}"
+	ProjectSection(ProjectDependencies) = postProject
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21} = {0008960E-E0DD-41A6-8265-00B31DDB4C21}
+	EndProjectSection
+EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "zlib", "zlib.vcproj", "{2D4F8105-7D21-454C-9932-B47CAB71A5C0}"
+	ProjectSection(ProjectDependencies) = postProject
+	EndProjectSection
+EndProject
+Global
+	GlobalSection(SolutionConfiguration) = preSolution
+		DLL Debug = DLL Debug
+		DLL Release = DLL Release
+		DLL VB = DLL VB
+		LIB Debug = LIB Debug
+		LIB Release = LIB Release
+	EndGlobalSection
+	GlobalSection(ProjectConfiguration) = postSolution
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Debug.ActiveCfg = DLL Debug|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Debug.Build.0 = DLL Debug|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Release.ActiveCfg = DLL Release|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL Release.Build.0 = DLL Release|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL VB.ActiveCfg = DLL VB|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.DLL VB.Build.0 = DLL VB|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Debug.ActiveCfg = LIB Debug|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Debug.Build.0 = LIB Debug|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Release.ActiveCfg = LIB Release|Win32
+		{0008960E-E0DD-41A6-8265-00B31DDB4C21}.LIB Release.Build.0 = LIB Release|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Debug.ActiveCfg = DLL Debug|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Debug.Build.0 = DLL Debug|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Release.ActiveCfg = DLL Release|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL Release.Build.0 = DLL Release|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL VB.ActiveCfg = DLL VB|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.DLL VB.Build.0 = DLL VB|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Debug.ActiveCfg = LIB Debug|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Debug.Build.0 = LIB Debug|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Release.ActiveCfg = LIB Release|Win32
+		{FD1C2F86-9EEF-47BD-95A4-530917E17FDA}.LIB Release.Build.0 = LIB Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Debug.ActiveCfg = DLL Debug|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Debug.Build.0 = DLL Debug|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Release.ActiveCfg = DLL Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL Release.Build.0 = DLL Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL VB.ActiveCfg = DLL Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.DLL VB.Build.0 = DLL Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Debug.ActiveCfg = LIB Debug|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Debug.Build.0 = LIB Debug|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Release.ActiveCfg = LIB Release|Win32
+		{2D4F8105-7D21-454C-9932-B47CAB71A5C0}.LIB Release.Build.0 = LIB Release|Win32
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+	EndGlobalSection
+	GlobalSection(ExtensibilityAddIns) = postSolution
+	EndGlobalSection
+EndGlobal
Index: /trunk/src/libs/libpng-1.6.45/projects/visualc71/libpng.vcproj
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/visualc71/libpng.vcproj	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/visualc71/libpng.vcproj	(revision 107811)
@@ -0,0 +1,419 @@
+<?xml version="1.0" encoding="Windows-1252"?>
+<VisualStudioProject
+	ProjectType="Visual C++"
+	Version="7.10"
+	Name="libpng"
+	RootNamespace="libpng">
+	<Platforms>
+		<Platform
+			Name="Win32"/>
+	</Platforms>
+	<Configurations>
+		<Configuration
+			Name="DLL Release|Win32"
+			OutputDirectory=".\Win32_DLL_Release"
+			IntermediateDirectory=".\Win32_DLL_Release"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;PNG_BUILD_DLL;ZLIB_DLL;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/libpng16.dll"
+				LinkIncremental="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="NDEBUG"
+				Culture="1033"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL Debug|Win32"
+			OutputDirectory=".\Win32_DLL_Debug"
+			IntermediateDirectory=".\Win32_DLL_Debug"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;PNG_DEBUG=1;PNG_BUILD_DLL;ZLIB_DLL;_CRT_SECURE_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="3"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/libpng16d.dll"
+				GenerateDebugInformation="TRUE"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="_DEBUG,PNG_DEBUG=1"
+				Culture="1033"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL VB|Win32"
+			OutputDirectory=".\Win32_DLL_VB"
+			IntermediateDirectory=".\Win32_DLL_VB"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;PNG_BUILD_DLL;ZLIB_DLL;PNGAPI=__stdcall;PNG_NO_MODULEDEF;PNG_LIBPNG_SPECIALBUILD;PNG_USER_PRIVATEBUILD;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/libpng16vb.dll"
+				LinkIncremental="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				AdditionalOptions="/d PNG_NO_PEDANTIC_WARNINGS /d PNG_LIBPNG_DLLFNAME_POSTFIX=&quot;&quot;&quot;&quot;VB&quot;&quot;&quot;&quot; /d PNG_LIBPNG_SPECIALBUILD=&quot;&quot;&quot;&quot;__stdcall calling convention used for exported functions&quot;&quot;&quot;&quot;"
+				PreprocessorDefinitions="NDEBUG"
+				Culture="1033"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib;$(IntDir)"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Release|Win32"
+			OutputDirectory=".\Win32_LIB_Release"
+			IntermediateDirectory=".\Win32_LIB_Release"
+			ConfigurationType="4">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="0"
+				EnableFunctionLevelLinking="TRUE"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLibrarianTool"
+				OutputFile="$(OutDir)/libpng.lib"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Debug|Win32"
+			OutputDirectory=".\Win32_LIB_Debug"
+			IntermediateDirectory=".\Win32_LIB_Debug"
+			ConfigurationType="4">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;DEBUG;PNG_DEBUG=1;_CRT_SECURE_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="1"
+				UsePrecompiledHeader="3"
+				PrecompiledHeaderThrough="pngpriv.h"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLibrarianTool"
+				OutputFile="$(OutDir)/libpngd.lib"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"
+				CommandLine="copy ..\..\scripts\pnglibconf.h.prebuilt ..\..\pnglibconf.h"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+	</Configurations>
+	<References>
+	</References>
+	<Files>
+		<Filter
+			Name="Source Files"
+			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
+			<File
+				RelativePath="..\..\png.c">
+				<FileConfiguration
+					Name="DLL Release|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL VB|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="0"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\pngerror.c">
+				<FileConfiguration
+					Name="DLL Release|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL VB|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32">
+					<Tool
+						Name="VCCLCompilerTool"
+						UsePrecompiledHeader="1"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\pngget.c">
+			</File>
+			<File
+				RelativePath="..\..\pngmem.c">
+			</File>
+			<File
+				RelativePath="..\..\pngpread.c">
+			</File>
+			<File
+				RelativePath="..\..\pngread.c">
+			</File>
+			<File
+				RelativePath="..\..\pngrio.c">
+			</File>
+			<File
+				RelativePath="..\..\pngrtran.c">
+			</File>
+			<File
+				RelativePath="..\..\pngrutil.c">
+			</File>
+			<File
+				RelativePath="..\..\pngset.c">
+			</File>
+			<File
+				RelativePath="..\..\pngtrans.c">
+			</File>
+			<File
+				RelativePath="..\..\pngwio.c">
+			</File>
+			<File
+				RelativePath="..\..\pngwrite.c">
+			</File>
+			<File
+				RelativePath="..\..\pngwtran.c">
+			</File>
+			<File
+				RelativePath="..\..\pngwutil.c">
+			</File>
+		</Filter>
+		<Filter
+			Name="Header Files"
+			Filter="h;hpp;hxx;hm;inl">
+			<File
+				RelativePath="..\..\png.h">
+			</File>
+			<File
+				RelativePath="..\..\pngconf.h">
+			</File>
+			<File
+				RelativePath="..\..\pngpriv.h">
+			</File>
+		</Filter>
+		<Filter
+			Name="Resource Files"
+			Filter="ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe">
+			<File
+				RelativePath="..\..\scripts\pngwin.rc">
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCResourceCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCResourceCompilerTool"/>
+				</FileConfiguration>
+			</File>
+		</Filter>
+		<File
+			RelativePath=".\PRJ0041.mak">
+			<FileConfiguration
+				Name="DLL Release|Win32">
+				<Tool
+					Name="VCCustomBuildTool"
+					Description="Create dummy include files to prevent &quot;Cannot find missing dependency...&quot; warnings."
+					CommandLine="nmake -f PRJ0041.mak IntDir=$(IntDir)"
+					Outputs="$(IntDir)\alloc.h;$(IntDir)\fp.h;$(IntDir)\m68881.h;$(IntDir)\mem.h;$(IntDir)\pngusr.h;$(IntDir)\strings.h;$(IntDir)\unistd.h;$(IntDir)\unixio.h"/>
+			</FileConfiguration>
+			<FileConfiguration
+				Name="DLL Debug|Win32">
+				<Tool
+					Name="VCCustomBuildTool"
+					Description="Create dummy include files to prevent &quot;Cannot find missing dependency...&quot; warnings."
+					CommandLine="nmake -f PRJ0041.mak IntDir=$(IntDir)"
+					Outputs="$(IntDir)\alloc.h;$(IntDir)\fp.h;$(IntDir)\m68881.h;$(IntDir)\mem.h;$(IntDir)\pngusr.h;$(IntDir)\strings.h;$(IntDir)\unistd.h;$(IntDir)\unixio.h"/>
+			</FileConfiguration>
+			<FileConfiguration
+				Name="DLL VB|Win32">
+				<Tool
+					Name="VCCustomBuildTool"
+					Description="Create dummy include files to prevent &quot;Cannot find missing dependency...&quot; warnings."
+					CommandLine="nmake -f PRJ0041.mak IntDir=$(IntDir)"
+					Outputs="$(IntDir)\alloc.h;$(IntDir)\fp.h;$(IntDir)\m68881.h;$(IntDir)\mem.h;$(IntDir)\pngusr.h;$(IntDir)\strings.h;$(IntDir)\unistd.h;$(IntDir)\unixio.h"/>
+			</FileConfiguration>
+		</File>
+		<File
+			RelativePath="README.txt">
+		</File>
+	</Files>
+	<Globals>
+	</Globals>
+</VisualStudioProject>
Index: /trunk/src/libs/libpng-1.6.45/projects/visualc71/pngtest.vcproj
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/visualc71/pngtest.vcproj	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/visualc71/pngtest.vcproj	(revision 107811)
@@ -0,0 +1,267 @@
+<?xml version="1.0" encoding="Windows-1252"?>
+<VisualStudioProject
+	ProjectType="Visual C++"
+	Version="7.10"
+	Name="pngtest"
+	RootNamespace="pngtest">
+	<Platforms>
+		<Platform
+			Name="Win32"/>
+	</Platforms>
+	<Configurations>
+		<Configuration
+			Name="DLL Release|Win32"
+			OutputDirectory=".\Win32_DLL_Release\Test"
+			IntermediateDirectory=".\Win32_DLL_Release\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;PNG_DLL;PNG_NO_STDIO;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				LinkIncremental="1"
+				SubSystem="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL Debug|Win32"
+			OutputDirectory=".\Win32_DLL_Debug\Test"
+			IntermediateDirectory=".\Win32_DLL_Debug\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;PNG_DLL;PNG_NO_STDIO;_CRT_SECURE_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="3"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				GenerateDebugInformation="TRUE"
+				SubSystem="1"
+				TargetMachine="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL VB|Win32"
+			OutputDirectory=".\Win32_DLL_VB\Test"
+			IntermediateDirectory=".\Win32_DLL_VB\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;PNG_DLL;PNG_NO_STDIO;PNGAPI=__stdcall;PNG_USER_PRIVATEBUILD;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="2"
+				CallingConvention="2"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\..\Win32_DLL_Release\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				LinkIncremental="1"
+				IgnoreDefaultLibraryNames="$(IntDir)\libpng16b.lib"
+				SubSystem="1"
+				TargetMachine="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Release|Win32"
+			OutputDirectory=".\Win32_LIB_Release\Test"
+			IntermediateDirectory=".\Win32_LIB_Release\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="0"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="3"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				LinkIncremental="1"
+				SubSystem="1"
+				TargetMachine="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Debug|Win32"
+			OutputDirectory=".\Win32_LIB_Debug\Test"
+			IntermediateDirectory=".\Win32_LIB_Debug\Test"
+			ConfigurationType="1">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..\scripts;..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="1"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="0"/>
+			<Tool
+				Name="VCCustomBuildTool"
+				Description="Testing..."
+				CommandLine="set path=$(OutDir)\..;$(OutDir)\..\ZLib
+$(TargetPath) ..\..\pngtest.png $(IntDir)\pngout.png"
+				Outputs="$(IntDir)\pngout.png"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)/pngtest.exe"
+				GenerateDebugInformation="TRUE"
+				SubSystem="1"
+				TargetMachine="1"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+	</Configurations>
+	<References>
+	</References>
+	<Files>
+		<Filter
+			Name="Source Files"
+			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
+			<File
+				RelativePath="..\..\pngtest.c">
+			</File>
+		</Filter>
+	</Files>
+	<Globals>
+	</Globals>
+</VisualStudioProject>
Index: /trunk/src/libs/libpng-1.6.45/projects/visualc71/zlib.vcproj
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/visualc71/zlib.vcproj	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/visualc71/zlib.vcproj	(revision 107811)
@@ -0,0 +1,391 @@
+<?xml version="1.0" encoding="Windows-1252"?>
+<VisualStudioProject
+	ProjectType="Visual C++"
+	Version="7.10"
+	Name="zlib">
+	<Platforms>
+		<Platform
+			Name="Win32"/>
+	</Platforms>
+	<Configurations>
+		<Configuration
+			Name="DLL Release|Win32"
+			OutputDirectory=".\Win32_DLL_Release\ZLib"
+			IntermediateDirectory=".\Win32_DLL_Release\ZLib"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="2"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="3"
+				CompileAs="1"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)\zlib1.dll"
+				LinkIncremental="1"
+				ModuleDefinitionFile="..\..\..\zlib\win32\zlib.def"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="NDEBUG"
+				Culture="1033"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="DLL Debug|Win32"
+			OutputDirectory=".\Win32_DLL_Debug\ZLib"
+			IntermediateDirectory=".\Win32_DLL_Debug\ZLib"
+			ConfigurationType="2">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="3"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="1"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLinkerTool"
+				OutputFile="$(OutDir)\zlib1d.dll"
+				ModuleDefinitionFile="..\..\..\zlib\win32\zlib.def"
+				GenerateDebugInformation="TRUE"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="_DEBUG"
+				Culture="1033"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCWebDeploymentTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Release|Win32"
+			OutputDirectory=".\Win32_LIB_Release\ZLib"
+			IntermediateDirectory=".\Win32_LIB_Release\ZLib"
+			ConfigurationType="4">
+			<Tool
+				Name="VCCLCompilerTool"
+				InlineFunctionExpansion="1"
+				AdditionalIncludeDirectories="..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;NDEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
+				StringPooling="TRUE"
+				RuntimeLibrary="0"
+				EnableFunctionLevelLinking="TRUE"
+				WarningLevel="3"
+				CompileAs="1"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLibrarianTool"
+				OutputFile="$(OutDir)\zlib.lib"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+		<Configuration
+			Name="LIB Debug|Win32"
+			OutputDirectory=".\Win32_LIB_Debug\ZLib"
+			IntermediateDirectory=".\Win32_LIB_Debug\ZLib"
+			ConfigurationType="4">
+			<Tool
+				Name="VCCLCompilerTool"
+				Optimization="0"
+				AdditionalIncludeDirectories="..\..\..\zlib"
+				PreprocessorDefinitions="WIN32;_DEBUG;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_WARNINGS"
+				BasicRuntimeChecks="3"
+				RuntimeLibrary="1"
+				WarningLevel="3"
+				DebugInformationFormat="4"
+				CompileAs="1"/>
+			<Tool
+				Name="VCCustomBuildTool"/>
+			<Tool
+				Name="VCLibrarianTool"
+				OutputFile="$(OutDir)\zlibd.lib"/>
+			<Tool
+				Name="VCMIDLTool"/>
+			<Tool
+				Name="VCPostBuildEventTool"/>
+			<Tool
+				Name="VCPreBuildEventTool"/>
+			<Tool
+				Name="VCPreLinkEventTool"/>
+			<Tool
+				Name="VCResourceCompilerTool"/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"/>
+			<Tool
+				Name="VCManagedWrapperGeneratorTool"/>
+			<Tool
+				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+		</Configuration>
+	</Configurations>
+	<References>
+	</References>
+	<Files>
+		<Filter
+			Name="Source Files"
+			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
+			<File
+				RelativePath="..\..\..\zlib\adler32.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\compress.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\crc32.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\deflate.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\gzlib.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\gzclose.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\gzread.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\gzwrite.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\infback.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inffast.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inflate.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inftrees.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\trees.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\uncompr.c">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\win32\zlib.def">
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\zutil.c">
+			</File>
+		</Filter>
+		<Filter
+			Name="Header Files"
+			Filter="h;hpp;hxx;hm;inl">
+			<File
+				RelativePath="..\..\..\zlib\crc32.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\deflate.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inffast.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inffixed.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inflate.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\inftrees.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\trees.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\zconf.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\zlib.h">
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\zutil.h">
+			</File>
+		</Filter>
+		<Filter
+			Name="Resource Files"
+			Filter="ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe">
+			<File
+				RelativePath="..\..\..\zlib\win32\zlib1.rc">
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCResourceCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCResourceCompilerTool"/>
+				</FileConfiguration>
+			</File>
+		</Filter>
+		<Filter
+			Name="Assembler Files (Unsupported)"
+			Filter="asm;obj;c;cpp;cxx;h;hpp;hxx">
+			<File
+				RelativePath="..\..\..\zlib\contrib\masmx86\gvmat32.asm">
+				<FileConfiguration
+					Name="DLL Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\contrib\masmx86\gvmat32c.c">
+				<FileConfiguration
+					Name="DLL Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCLCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCLCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCLCompilerTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCLCompilerTool"/>
+				</FileConfiguration>
+			</File>
+			<File
+				RelativePath="..\..\..\zlib\contrib\masmx86\inffas32.asm">
+				<FileConfiguration
+					Name="DLL Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="DLL Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Release|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+				<FileConfiguration
+					Name="LIB Debug|Win32"
+					ExcludedFromBuild="TRUE">
+					<Tool
+						Name="VCCustomBuildTool"/>
+				</FileConfiguration>
+			</File>
+		</Filter>
+		<File
+			RelativePath="README.txt">
+		</File>
+	</Files>
+	<Globals>
+	</Globals>
+</VisualStudioProject>
Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/README.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/vstudio/README.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/vstudio/README.txt	(revision 107811)
@@ -0,0 +1,87 @@
+Instructions for building libpng using Microsoft Visual Studio
+==============================================================
+
+Copyright (c) 2018,2022 Cosmin Truta
+Copyright (c) 2010,2013,2015 Glenn Randers-Pehrson
+
+This code is released under the libpng license.
+For conditions of distribution and use, see the disclaimer and license
+in png.h
+
+This directory contains a solution for building libpng under Microsoft
+Visual Studio 2019.  It may also work under earlier or later versions
+of Visual Studio.  You should be familiar with Visual Studio before
+using this solution.
+
+Initial preparations
+--------------------
+You must enter some information in zlib.props before attempting to
+build with this 'solution'.  Please read and edit zlib.props first.
+You will probably not be familiar with the contents of zlib.props -
+do not worry, it is mostly harmless.
+
+This is all you need to do to build the 'release' and 'release library'
+configurations.
+
+Debugging
+---------
+The release configurations default to /Ox optimization.  Full debugging
+information is produced (in the .pdb), but if you encounter a problem
+the optimization may make it difficult to debug.  Simply rebuild with a
+lower optimization level (e.g. /Od.)
+
+Linking your application
+------------------------
+Normally you should link against the 'release' configuration.  This
+builds a DLL for libpng with the default runtime options used by Visual
+Studio.  In particular the runtime library is the "MultiThreaded DLL"
+version.  If you use Visual Studio defaults to build your application,
+you should have no problems.
+
+If you don't use the Visual Studio defaults your application must still
+be built with the default runtime option (/MD).  If, for some reason,
+it is not then your application will crash inside libpng16.dll as soon
+as libpng tries to read from a file handle you pass in.
+
+If you do not want to use the DLL, and prefer static linking instead,
+you may choose the 'release library' configuration.  This is built with
+a non-standard runtime library - the "MultiThreaded" version.  When you
+build your application, it must be compiled with this option (/MT),
+otherwise it will not build (if you are lucky) or it will crash (if you
+are not.) See the WARNING file that is distributed with this README.
+
+Stop reading here
+-----------------
+You have enough information to build a working application.
+
+Debug versions have limited support
+-----------------------------------
+This solution includes limited support for debug versions of libpng.
+You do not need these unless your own solution itself uses debug builds
+(it is far more effective to debug on the release builds, there is no
+point building a special debug build unless you have heap corruption
+problems that you can't track down.)
+
+The debug build of libpng is minimally supported.  Support for debug
+builds of zlib is also minimal.  Please keep this in mind, if you want
+to use it.
+
+WARNING
+-------
+Libpng 1.6.x does not use the default run-time library when building
+static library builds of libpng; instead of the shared DLL runtime, it
+uses a static runtime.  If you need to change this, make sure to change
+the setting on all the relevant projects:
+
+    libpng
+    zlib
+    all the test programs
+
+The runtime library settings for each build are as follows:
+
+               Release        Debug
+    DLL         /MD            /MDd
+    Library     /MT            /MTd
+
+Also, be sure to build libpng, zlib, and your project, all for the same
+platform (e.g., 32-bit or 64-bit).
Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/libpng/libpng.vcxproj
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/vstudio/libpng/libpng.vcxproj	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/vstudio/libpng/libpng.vcxproj	(revision 107811)
@@ -0,0 +1,458 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug Library|ARM64">
+      <Configuration>Debug Library</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug Library|Win32">
+      <Configuration>Debug Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|ARM64">
+      <Configuration>Debug</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|ARM64">
+      <Configuration>Release Library</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|Win32">
+      <Configuration>Release Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|ARM64">
+      <Configuration>Release</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{D6973076-9317-4EF2-A0B8-B7A18AC0713E}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>libpng</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(SolutionDir)\zlib.props" />
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <CharacterSet>MultiByte</CharacterSet>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <CharacterSet>MultiByte</CharacterSet>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|ARM64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|ARM64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <CharacterSet>MultiByte</CharacterSet>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|ARM64'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
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Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/pnglibconf/pnglibconf.vcxproj
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Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngstest/pngstest.vcxproj
===================================================================
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Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngtest/pngtest.vcxproj
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngtest/pngtest.vcxproj	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngtest/pngtest.vcxproj	(revision 107811)
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+      <Command>"$(OutDir)pngtest.exe" ..\..\..\pngtest.png "$(IntDir)pngout.png"</Command>
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Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngunknown/pngunknown.vcxproj
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngunknown/pngunknown.vcxproj	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngunknown/pngunknown.vcxproj	(revision 107811)
@@ -0,0 +1,424 @@
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+      <Command>"$(OutDir)pngunknown.exe" --strict --default --touch "$(IntDir)pngunknown.out" ../../../pngtest.png</Command>
+      <Outputs>$(IntDir)pngunknown.out</Outputs>
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Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngvalid/pngvalid.vcxproj
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngvalid/pngvalid.vcxproj	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/vstudio/pngvalid/pngvalid.vcxproj	(revision 107811)
@@ -0,0 +1,424 @@
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Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/vstudio.sln
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/vstudio/vstudio.sln	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/vstudio/vstudio.sln	(revision 107811)
@@ -0,0 +1,174 @@
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Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/zlib.props
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/vstudio/zlib.props	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/vstudio/zlib.props	(revision 107811)
@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+ * zlib.props - location of zlib source
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+
+ * You may need to edit this file in order to update the location
+ * of the zlib source code.
+ -->
+
+<Project ToolsVersion="4.0"
+   xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup Label="Globals">
+    <!-- Place the name of the directory containing the source of zlib used for
+	 debugging in this property.
+
+         The directory need only contain the '.c' and '.h' files from the
+	 source.
+
+	 If you use a relative directory name (as below) then it must be
+	 relative to the project directories; these are one level deeper than
+	 the directories containing this file.
+
+	 If the version of zlib you use does not match that used when the
+	 distribution was built you will get warnings from pngtest that the zlib
+	 versions do not match.  The zlib version used in this build is recorded
+	 below:
+     -->
+    <ZLibSrcDir>..\..\..\..\zlib</ZLibSrcDir>
+
+    <!-- The following line allows compilation for an ARM target with Visual
+         Studio 2012.  Notice that this is not supported by the Visual Studio
+         2012 IDE and that the programs that result cannot be run unless they
+         signed by Microsoft.  This is therefore untested; only Microsoft can
+         test it:
+     -->
+    <WindowsSDKDesktopARMSupport>true</WindowsSDKDesktopARMSupport>
+
+    <!-- The following lines provide a global (solution level) control of the
+         warnings issued by the compiler, these are used in the individual
+         project files (*/*.vcxproj) with, for zlib, some extra disables.
+
+         Different versions of Visual Studio may require different settings,
+         these settings work with Visual Studio 2013.  Just set
+         TreatWarningAsError to false to check the build without failing on
+         errors.
+     -->
+   <WarningLevel>EnableAllWarnings</WarningLevel>
+   <TreatWarningAsError>true</TreatWarningAsError>
+   <DisableSpecificWarnings>4255;4668;4710;4711;4746;4820;4996</DisableSpecificWarnings>
+  </PropertyGroup>
+</Project>
Index: /trunk/src/libs/libpng-1.6.45/projects/vstudio/zlib/zlib.vcxproj
===================================================================
--- /trunk/src/libs/libpng-1.6.45/projects/vstudio/zlib/zlib.vcxproj	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/projects/vstudio/zlib/zlib.vcxproj	(revision 107811)
@@ -0,0 +1,322 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug Library|ARM64">
+      <Configuration>Debug Library</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug Library|Win32">
+      <Configuration>Debug Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|ARM64">
+      <Configuration>Debug</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|ARM64">
+      <Configuration>Release Library</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release Library|Win32">
+      <Configuration>Release Library</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|ARM64">
+      <Configuration>Release</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="$(ZLibSrcDir)\adler32.c" />
+    <ClCompile Include="$(ZLibSrcDir)\compress.c" />
+    <ClCompile Include="$(ZLibSrcDir)\crc32.c" />
+    <ClCompile Include="$(ZLibSrcDir)\deflate.c" />
+    <ClCompile Include="$(ZLibSrcDir)\infback.c" />
+    <ClCompile Include="$(ZLibSrcDir)\inffast.c" />
+    <ClCompile Include="$(ZLibSrcDir)\inflate.c" />
+    <ClCompile Include="$(ZLibSrcDir)\inftrees.c" />
+    <ClCompile Include="$(ZLibSrcDir)\trees.c" />
+    <ClCompile Include="$(ZLibSrcDir)\uncompr.c" />
+    <ClCompile Include="$(ZLibSrcDir)\zutil.c" />
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{60F89955-91C6-3A36-8000-13C592FEC2DF}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>zlib</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(SolutionDir)\zlib.props" />
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|ARM64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|ARM64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <PlatformToolset>v142</PlatformToolset>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
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+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
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+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" />
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+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|ARM64'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|ARM64'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
+    <ClCompile>
+      <PreprocessorDefinitions>WIN32;_DEBUG;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <WarningLevel>Level3</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>false</TreatWarningAsError>
+    </ClCompile>
+    <Link>
+      <TargetMachine>MachineX86</TargetMachine>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|ARM64'">
+    <ClCompile>
+      <PreprocessorDefinitions>WIN32;_DEBUG;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <WarningLevel>Level3</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>false</TreatWarningAsError>
+    </ClCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PreprocessorDefinitions>WIN32;_DEBUG;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <WarningLevel>Level3</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>false</TreatWarningAsError>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <TargetMachine>MachineX86</TargetMachine>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">
+    <ClCompile>
+      <PreprocessorDefinitions>WIN32;_DEBUG;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <WarningLevel>Level3</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Disabled</Optimization>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>false</TreatWarningAsError>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>false</TreatWarningAsError>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <PreprocessorDefinitions>WIN32;NDEBUG;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+    </ClCompile>
+    <Link>
+      <TargetMachine>MachineX86</TargetMachine>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+    <Lib>
+      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
+    </Lib>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|ARM64'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>false</TreatWarningAsError>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <PreprocessorDefinitions>WIN32;NDEBUG;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+    </ClCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+    </Link>
+    <Lib>
+      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
+    </Lib>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <PreprocessorDefinitions>WIN32;NDEBUG;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+    </ClCompile>
+    <Link>
+      <TargetMachine>MachineX86</TargetMachine>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+    </Link>
+    <Lib>
+      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
+    </Lib>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">
+    <ClCompile>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <Optimization>Full</Optimization>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <WholeProgramOptimization>true</WholeProgramOptimization>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <BrowseInformation>true</BrowseInformation>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
+      <PreprocessorDefinitions>WIN32;NDEBUG;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+    </ClCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Windows</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+    </Link>
+    <Lib>
+      <LinkTimeCodeGeneration>true</LinkTimeCodeGeneration>
+    </Lib>
+  </ItemDefinitionGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
Index: /trunk/src/libs/libpng-1.6.45/scripts/README.txt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/README.txt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/README.txt	(revision 107811)
@@ -0,0 +1,79 @@
+
+Makefiles for libpng
+
+pnglibconf.h.prebuilt  =>  Configuration settings
+ makefile.linux    =>  Linux/ELF makefile
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.linux-opt=>  Linux/ELF makefile with hardware optimizations on
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
+ makefile.acorn    =>  Acorn makefile
+ makefile.aix      =>  AIX/gcc makefile
+ makefile.amiga    =>  Amiga makefile
+ makefile.atari    =>  Atari makefile
+ makefile.bc32     =>  32-bit Borland C++ (all modules compiled in C mode)
+ makefile.beos     =>  BeOS makefile
+ makefile.clang    =>  Generic clang makefile
+ makefile.darwin   =>  Darwin makefile, for macOS (formerly Mac OS X)
+ makefile.dec      =>  DEC Alpha UNIX makefile
+ makefile.dj2      =>  DJGPP 2 makefile
+ makefile.freebsd  =>  FreeBSD makefile
+ makefile.gcc      =>  Generic gcc makefile
+ makefile.hpgcc    =>  HPUX makefile using gcc
+ makefile.hpux     =>  HPUX (10.20 and 11.00) makefile
+ makefile.hp64     =>  HPUX (10.20 and 11.00) makefile, 64-bit
+ makefile.ibmc     =>  IBM C/C++ version 3.x for Win32 and OS/2 (static)
+ makefile.intel    =>  Intel C/C++ version 4.0 and later
+ makefile.mips     =>  MIPS makefile
+ makefile.netbsd   =>  NetBSD/cc makefile, makes shared libpng.so
+ makefile.openbsd  =>  OpenBSD makefile
+ makefile.sco      =>  SCO OSr5 ELF and Unixware 7 with Native cc
+ makefile.sggcc    =>  Silicon Graphics makefile
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
+ makefile.solaris  =>  Solaris 2.X makefile
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.so9      =>  Solaris 9 makefile
+                       (gcc, creates shared libpng16.so.16.1.6.*)
+ makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
+ makefile.sunos    =>  Sun makefile
+ makefile.32sunu   =>  Sun Ultra 32-bit makefile
+ makefile.64sunu   =>  Sun Ultra 64-bit makefile
+ makefile.vcwin32  =>  makefile for Microsoft Visual C++ 4.0 and later
+ makevms.com       =>  VMS build script
+ smakefile.ppc     =>  AMIGA smakefile for SAS C V6.58/7.00 PPC compiler
+                       (Requires SCOPTIONS, copied from scripts/SCOPTIONS.ppc)
+
+Other supporting scripts:
+ README.txt        =>  This file
+ descrip.mms       =>  VMS makefile for MMS or MMK
+ libpng-config-body.in => used by several makefiles to create libpng-config
+ libpng-config-head.in => used by several makefiles to create libpng-config
+ libpng.pc.in      =>  Used by several makefiles to create libpng.pc
+ pngwin.rc         =>  Used by the visualc71 project
+ pngwin.def        =>  Used by makefile.os2
+ pngwin.dfn        =>  Used to maintain pngwin.def
+ SCOPTIONS.ppc     =>  Used with smakefile.ppc
+
+ checksym.awk      =>  Used for maintaining pnglibconf.h
+ def.dfn           =>  Used for maintaining pnglibconf.h
+ options.awk       =>  Used for maintaining pnglibconf.h
+ pnglibconf.dfa    =>  Used for maintaining pnglibconf.h
+ pnglibconf.mak    =>  Used for maintaining pnglibconf.h
+ sym.dfn           =>  Used for symbol versioning
+ symbols.def       =>  Used for symbol versioning
+ symbols.dfn       =>  Used for symbol versioning
+ vers.dfn          =>  Used for symbol versioning
+
+ libtool.m4        =>  Used by autoconf tools
+ ltoptions.m4      =>  Used by autoconf tools
+ ltsugar.m4        =>  Used by autoconf tools
+ ltversion.m4      =>  Used by autoconf tools
+ lt~obsolete.m4    =>  Used by autoconf tools
+
+ intprefix.dfn     =>  Used by autoconf tools
+ macro.lst         =>  Used by autoconf tools
+ prefix.dfn        =>  Used by autoconf tools
+
+Further information can be found in comments in the individual scripts and
+makefiles.
Index: /trunk/src/libs/libpng-1.6.45/scripts/SCOPTIONS.ppc
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/SCOPTIONS.ppc	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/SCOPTIONS.ppc	(revision 107811)
@@ -0,0 +1,7 @@
+OPTIMIZE
+OPTPEEP
+OPTTIME
+OPTSCHED
+AUTOREGISTER
+PARMS=REGISTERS
+INCLUDEDIR=hlp:ppc/include
Index: /trunk/src/libs/libpng-1.6.45/scripts/checksym.awk
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/checksym.awk	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/checksym.awk	(revision 107811)
@@ -0,0 +1,180 @@
+#!/bin/awk -f
+
+# Check a list of symbols against the master definition
+# (official) list.  Arguments:
+#
+# awk -f checksym.awk official-def list-to-check
+#
+# Output is a file in the current directory called 'symbols.new',
+# the value of the awk variable "of" (which can be changed on the
+# command line if required.)  stdout holds error messages.  Error
+# code indicates success or failure.
+#
+# NOTE: this is a pure, old fashioned, awk script.  It will
+# work with any awk
+
+BEGIN{
+   err=0
+   master=""        # master file
+   official[1] = "" # defined symbols from master file
+   symbol[1] = ""   # defined symbols from png.h
+   removed[1] = ""  # removed symbols from png.h
+   lasto = 0        # last ordinal value from png.h
+   mastero = 0      # highest ordinal in master file
+   symbolo = 0      # highest ordinal in png.h
+   missing = "error"# log an error on missing symbols
+   of="symbols.new" # default to a fixed name
+}
+
+# Read existing definitions from the master file (the first
+# file on the command line.)  This must be a def file and it
+# has definition lines (others are ignored) of the form:
+#
+#   symbol @ordinal
+#
+master == "" {
+   master = FILENAME
+}
+FILENAME==master && NF==2 && $2~/^@/ && $1!~/^;/ {
+   o=0+substr($2,2)
+   if (o > 0) {
+      if (official[o] == "") {
+         official[o] = $1
+         if (o > mastero) mastero = o
+         next
+      } else
+         print master ": duplicated symbol:", official[o] ":", $0
+   } else
+      print master ": bad export line format:", $0
+   err = 1
+}
+FILENAME==master && $1==";missing" && NF==2{
+   # This allows the master file to control how missing symbols
+   # are handled; symbols that aren't in either the master or
+   # the new file.  Valid values are 'ignore', 'warning' and
+   # 'error'
+   missing = $2
+}
+FILENAME==master {
+   next
+}
+
+# Read new definitions, these are free form but the lines must
+# just be symbol definitions.  Lines will be commented out for
+# 'removed' symbols, introduced in png.h using PNG_REMOVED rather
+# than PNG_EXPORT.  Use symbols.dfn or pngwin.dfn to generate the
+# input file.
+#
+#  symbol @ordinal   # two fields, exported symbol
+#  ; symbol @ordinal # three fields, removed symbol
+#  ; @ordinal        # two fields, the last ordinal
+NF==2 && $1 == ";" && $2 ~ /^@[1-9][0-9]*$/ { # last ordinal
+   o=0+substr($2,2)
+   if (lasto == 0 || lasto == o)
+      lasto=o
+   else {
+      print "png.h: duplicated last ordinal:", lasto, o
+      err = 1
+   }
+   next
+}
+NF==3 && $1 == ";" && $3 ~ /^@[1-9][0-9]*$/ { # removed symbol
+   o=0+substr($3,2)
+   if (removed[o] == "" || removed[o] == $2) {
+      removed[o] = $2
+      if (o > symbolo) symbolo = o
+   } else {
+      print "png.h: duplicated removed symbol", o ": '" removed[o] "' != '" $2 "'"
+      err = 1
+   }
+   next
+}
+NF==2 && $2 ~ /^@[1-9][0-9]*$/ { # exported symbol
+   o=0+substr($2,2)
+   if (symbol[o] == "" || symbol[o] == $1) {
+      symbol[o] = $1
+      if (o > symbolo) symbolo = o
+   } else {
+      print "png.h: duplicated symbol", o ": '" symbol[o] "' != '" $1 "'"
+      err = 1
+   }
+}
+{
+   next # skip all other lines
+}
+
+# At the end check for symbols marked as both duplicated and removed
+END{
+   if (symbolo > lasto) {
+      print "highest symbol ordinal in png.h,",
+            symbolo ", exceeds last ordinal from png.h", lasto
+      err = 1
+   }
+   if (mastero > lasto) {
+      print "highest symbol ordinal in", master ",",
+            mastero ", exceeds last ordinal from png.h", lasto
+      err = 1
+   }
+   unexported=0
+   # Add a standard header to symbols.new:
+   print ";Version INSERT-VERSION-HERE" >of
+   print ";--------------------------------------------------------------" >of
+   print "; LIBPNG symbol list as a Win32 DEF file" >of
+   print "; Contains all the symbols that can be exported from libpng" >of
+   print ";--------------------------------------------------------------" >of
+   print "LIBRARY" >of
+   print "" >of
+   print "EXPORTS" >of
+
+   for (o=1; o<=lasto; ++o) {
+      if (symbol[o] == "" && removed[o] == "") {
+         if (unexported == 0) unexported = o
+         if (official[o] == "") {
+            # missing in export list too, so ok
+            if (o < lasto) continue
+         }
+      }
+      if (unexported != 0) {
+         # Symbols in the .def but not in the new file are errors, but
+         # the 'unexported' symbols aren't in either.  By default this
+         # is an error too (see the setting of 'missing' at the start),
+         # but this can be reset on the command line or by stuff in the
+         # file - see the comments above.
+         if (missing != "ignore") {
+            if (o-1 > unexported)
+               print "png.h:", missing ": missing symbols:", unexported "-" o-1
+            else
+               print "png.h:", missing ": missing symbol:", unexported
+            if (missing != "warning")
+               err = 1
+         }
+         unexported = 0
+      }
+      if (symbol[o] != "" && removed[o] != "") {
+         print "png.h: symbol", o,
+               "both exported as '" symbol[o] "' and removed as '" removed[o] "'"
+         err = 1
+      } else if (symbol[o] != official[o]) {
+         # either the symbol is missing somewhere or it changed
+         err = 1
+         if (symbol[o] == "")
+            print "png.h: symbol", o,
+                  "is exported as '" official[o] "' in", master
+         else if (official[o] == "")
+            print "png.h: exported symbol", o,
+                  "'" symbol[o] "' not present in", master
+         else
+            print "png.h: exported symbol", o,
+                  "'" symbol[o] "' exists as '" official[o] "' in", master
+      }
+
+      # Finally generate symbols.new
+      if (symbol[o] != "")
+         print " " symbol[o], "@" o > of
+   }
+
+   if (err != 0) {
+      print "*** A new list is in", of, "***"
+      exit 1
+   }
+}
Index: /trunk/src/libs/libpng-1.6.45/scripts/descrip.mms
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/descrip.mms	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/descrip.mms	(revision 107811)
@@ -0,0 +1,47 @@
+
+cc_defs = /inc=$(ZLIBSRC)
+c_deb =
+
+.ifdef __DECC__
+pref = /prefix=all
+.endif
+
+OBJS = png.obj, pngerror.obj, pngget.obj, pngmem.obj, pngpread.obj,\
+       pngread.obj, pngrio.obj, pngrtran.obj, pngrutil.obj, pngset.obj,\
+       pngtrans.obj, pngwio.obj, pngwrite.obj, pngwtran.obj, pngwutil.obj
+
+CFLAGS = $(C_DEB) $(CC_DEFS) $(PREF)
+
+all : pngtest.exe libpng.olb
+	@ write sys$output " pngtest available"
+
+libpng.olb : libpng.olb($(OBJS))
+	@ write sys$output " libpng available"
+
+pngtest.exe : pngtest.obj libpng.olb
+	link pngtest,libpng.olb/lib,$(ZLIBSRC)libz.olb/lib
+
+test : pngtest.exe
+	run pngtest
+
+clean :
+	delete *.obj;*,*.exe;
+
+# Other dependencies.
+png.obj :      png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngerror.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngget.obj :   png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngmem.obj :   png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngpread.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngread.obj :  png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrio.obj :   png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngrutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngset.obj :   png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngtrans.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwio.obj :   png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwrite.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwtran.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+pngwutil.obj : png.h, pngconf.h, pnglibconf.h, pngpriv.h, pngstruct.h,pnginfo.h, pngdebug.h
+
+pngtest.obj :  png.h, pngconf.h, pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/dfn.awk
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/dfn.awk	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/dfn.awk	(revision 107811)
@@ -0,0 +1,203 @@
+#!/bin/awk -f
+
+# scripts/dfn.awk - process a .dfn file
+#
+# Copyright (c) 2013-2014 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# The output of this script is written to the file given by
+# the variable 'out', which should be set on the command line.
+# Error messages are printed to stdout and if any are printed
+# the script will exit with error code 1.
+
+BEGIN{
+   out="/dev/null"       # as a flag
+   out_count=0           # count of output lines
+   err=0                 # set if an error occurred
+   sort=0                # sort the output
+   array[""]=""
+}
+
+# The output file must be specified before any input:
+NR==1 && out == "/dev/null" {
+   print "out=output.file must be given on the command line"
+   # but continue without setting the error code; this allows the
+   # script to be checked easily
+}
+
+# Output can be sorted; two lines are recognized
+$1 == "PNG_DFN_START_SORT"{
+   sort=0+$2
+   next
+}
+
+$1 ~ /^PNG_DFN_END_SORT/{
+   # Do a very simple, slow, sort; notice that blank lines won't be
+   # output by this
+   for (entry in array) {
+      while (array[entry] != "") {
+         key = entry
+         value = array[key]
+         array[key] = ""
+
+         for (alt in array) {
+            if (array[alt] != "" && alt < key) {
+               array[key] = value
+               value = array[alt]
+               key = alt
+               array[alt] = ""
+            }
+         }
+
+         print value >out
+      }
+   }
+   sort=0
+   next
+}
+
+/^[^"]*PNG_DFN *".*"[^"]*$/{
+   # A definition line, apparently correctly formatted; extract the
+   # definition then replace any doubled "" that remain with a single
+   # double quote.  Notice that the original doubled double quotes
+   # may have been split by tokenization
+   #
+   # Sometimes GCC splits the PNG_DFN lines; we know this has happened
+   # if the quotes aren't closed and must read another line.  In this
+   # case it is essential to reject lines that start with '#' because those
+   # are introduced #line directives.
+   orig=$0
+   line=$0
+   lineno=FNR
+   if (lineno == "") lineno=NR
+
+   if (sub(/^[^"]*PNG_DFN *"/,"",line) != 1) {
+	print "line", lineno ": processing failed:"
+	print orig
+	err=1
+       next
+   } else {
+	++out_count
+   }
+
+   # Now examine quotes within the value:
+   #
+   #   @" - delete this and any following spaces
+   #   "@ - delete this and any preceding spaces
+   #   @' - replace this by a double quote
+   #
+   # This allows macro substitution by the C compiler thus:
+   #
+   #   #define first_name John
+   #   #define last_name Smith
+   #
+   #	PNG_DFN"#define name @'@" first_name "@ @" last_name "@@'"
+   #
+   # Might get C preprocessed to:
+   #
+   #   PNG_DFN "#define foo @'@" John "@ @" Smith "@@'"
+   #
+   # Which this script reduces to:
+   #
+   #	#define name "John Smith"
+   #
+   while (1) {
+      # While there is an @" remove it and the next "@
+      if (line ~ /@"/) {
+         if (line ~ /@".*"@/) {
+            # Do this special case first to avoid swallowing extra spaces
+            # before or after the @ stuff:
+            if (!sub(/@" *"@/, "", line)) {
+               # Ok, do it in pieces - there has to be a non-space between the
+               # two.  NOTE: really weird things happen if a leading @" is
+               # lost - the code will error out below (I believe).
+               if (!sub(/@" */, "", line) || !sub(/ *"@/, "", line)) {
+                  print "line", lineno, ": internal error:", orig
+                  exit 1
+               }
+            }
+         }
+
+         # There is no matching "@.  Assume a split line
+         else while (1) {
+            if (getline nextline) {
+               # If the line starts with '#' it is a preprocessor line directive
+               # from cc -E; skip it:
+               if (nextline !~ /^#/) {
+                  line = line " " nextline
+                  break
+               }
+            } else {
+               # This is end-of-input - probably a missing "@ on the first line:
+               print "line", lineno ": unbalanced @\" ... \"@ pair"
+               err=1
+               next
+            }
+         }
+
+         # Keep going until all the @" have gone
+         continue
+      }
+
+      # Attempt to remove a trailing " (not preceded by '@') - if this can
+      # be done, stop now; if not assume a split line again
+      if (sub(/"[^"]*$/, "", line))
+         break
+
+      # Read another line
+      while (1) {
+         if (getline nextline) {
+            if (nextline !~ /^#/) {
+               line = line " " nextline
+               # Go back to stripping @" "@ pairs
+               break
+            }
+         } else {
+            print "line", lineno ": unterminated PNG_DFN string"
+            err=1
+            next
+         }
+      }
+   }
+
+   # Put any needed double quotes in (at the end, because these would otherwise
+   # interfere with the processing above.)
+   gsub(/@'/,"\"", line)
+
+   # Remove any trailing spaces (not really required, but for
+   # editorial consistency
+   sub(/ *$/, "", line)
+
+   # Remove trailing CR
+   sub(/
+$/, "", line)
+
+   if (sort) {
+      if (split(line, parts) < sort) {
+         print "line", lineno ": missing sort field:", line
+         err=1
+      } else
+         array[parts[sort]] = line
+   }
+
+   else
+      print line >out
+   next
+}
+
+/PNG_DFN/{
+   print "line", NR, "incorrectly formatted PNG_DFN line:"
+   print $0
+   err = 1
+}
+
+END{
+   if (out_count > 0 || err > 0)
+	exit err
+
+   print "no definition lines found"
+   exit 1
+}
Index: /trunk/src/libs/libpng-1.6.45/scripts/intprefix.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/intprefix.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/intprefix.c	(revision 107811)
@@ -0,0 +1,21 @@
+
+/* intprefix.c - generate an unprefixed internal symbol list
+ *
+ * Copyright (c) 2013-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_INTERNAL_DATA(type, name, array)\
+        PNG_DFN "@" name "@"
+
+#define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
+        PNG_DFN "@" name "@"
+
+#define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
+        PNG_DFN "@" name "@"
+
+#define PNGPREFIX_H /* self generation */
+#include "../pngpriv.h"
Index: /trunk/src/libs/libpng-1.6.45/scripts/libpng-config-body.in
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/libpng-config-body.in	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/libpng-config-body.in	(revision 107811)
@@ -0,0 +1,96 @@
+
+usage()
+{
+    cat <<EOF
+Usage: libpng-config [OPTION] ...
+
+Known values for OPTION are:
+
+  --prefix        print libpng prefix
+  --libdir        print path to directory containing library
+  --libs          print library linking information
+  --ccopts        print compiler options
+  --cppflags      print pre-processor flags
+  --cflags        print preprocessor flags, I_opts, and compiler options
+  --I_opts        print "-I" include options
+  --L_opts        print linker "-L" flags for dynamic linking
+  --R_opts        print dynamic linker "-R" or "-rpath" flags
+  --ldopts        print linker options
+  --ldflags       print linker flags (ldopts, L_opts, R_opts, and libs)
+  --static        revise subsequent outputs for static linking
+  --help          print this help and exit
+  --version       print version information
+EOF
+
+    exit $1
+}
+
+if test $# -eq 0; then
+    usage 1
+fi
+
+while test $# -gt 0; do
+    case "$1" in
+
+    --prefix)
+        echo ${prefix}
+        ;;
+
+    --version)
+        echo ${version}
+        exit 0
+        ;;
+
+    --help)
+        usage 0
+        ;;
+
+    --ccopts)
+        echo ${ccopts}
+        ;;
+
+    --cppflags)
+        echo ${cppflags}
+        ;;
+
+    --cflags)
+        echo ${I_opts} ${cppflags} ${ccopts}
+        ;;
+
+    --libdir)
+        echo ${libdir}
+        ;;
+
+    --libs)
+        echo ${libs}
+        ;;
+
+    --I_opts)
+        echo ${I_opts}
+        ;;
+
+    --L_opts)
+        echo ${L_opts}
+        ;;
+
+    --R_opts)
+        echo ${R_opts}
+        ;;
+
+    --ldflags)
+        echo ${ldflags} ${L_opts} ${R_opts} ${libs}
+        ;;
+
+    --static)
+        R_opts=""
+        ;;
+
+    *)
+        usage
+        exit 1
+        ;;
+    esac
+    shift
+done
+
+exit 0
Index: /trunk/src/libs/libpng-1.6.45/scripts/libpng-config-head.in
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/libpng-config-head.in	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/libpng-config-head.in	(revision 107811)
@@ -0,0 +1,24 @@
+#! /bin/sh
+
+# libpng-config
+# provides configuration info for libpng.
+
+# Copyright (C) 2002 Glenn Randers-Pehrson
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Modeled after libxml-config.
+
+version=1.6.43
+prefix=""
+libdir=""
+libs=""
+I_opts=""
+L_opts=""
+R_opts=""
+cppflags=""
+ccopts=""
+ldopts=""
+
Index: /trunk/src/libs/libpng-1.6.45/scripts/libpng.pc.in
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/libpng.pc.in	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/libpng.pc.in	(revision 107811)
@@ -0,0 +1,10 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@/libpng16
+
+Name: libpng
+Description: Loads and saves PNG files
+Version: 1.6.43
+Libs: -L${libdir} -lpng16
+Cflags: -I${includedir}
Index: /trunk/src/libs/libpng-1.6.45/scripts/macro.lst
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/macro.lst	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/macro.lst	(revision 107811)
@@ -0,0 +1,3 @@
+get_uint_32(buf)
+get_uint_16(buf)
+get_int_32(buf)
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.32sunu
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.32sunu	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.32sunu	(revision 107811)
@@ -0,0 +1,130 @@
+# makefile for libpng on Solaris 2.x with cc
+# Contributed by William L. Sebok, based on makefile.linux
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1998 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+CC=cc
+AR=ar
+RANLIB=echo
+LN_SF=ln -f -s
+RM_F=/bin/rm -f
+
+SUN_CC_FLAGS=-fast -xtarget=ultra
+SUN_LD_FLAGS=-fast -xtarget=ultra
+
+# Where the zlib library and include files are located
+# Changing these to ../zlib poses a security risk.  If you want
+# to have zlib in an adjacent directory, specify the full path instead of "..".
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+
+ZLIBLIB=/usr/lib
+ZLIBINC=/usr/include
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=$(SUN_CC_FLAGS) # $(WARNMORE) -g
+ARFLAGS=rc
+LDFLAGS=$(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) libpng.a -lz -lm
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest
+
+include scripts/pnglibconf.mak
+DELETE = $(RM_F)
+DFNFLAGS = $(DEFS) $(CPPFLAGS)
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	@case "`type ld`" in *ucb*) \
+	echo; \
+	echo '## WARNING:'; \
+	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
+	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
+	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
+	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
+	echo '## at all.  If it is, things are likely to break because of'; \
+	echo '## the libucb dependency that is created.'; \
+	echo; \
+	;; \
+	esac
+	$(LD) -G -L$(ZLIBLIB) -R$(ZLIBLIB) -h $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o      png.pic.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o   pngget.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o   pngmem.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o  pngread.pic.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o   pngrio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o   pngset.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o   pngwio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.64sunu
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.64sunu	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.64sunu	(revision 107811)
@@ -0,0 +1,130 @@
+# makefile for libpng on Solaris 2.x with cc
+# Contributed by William L. Sebok, based on makefile.linux
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1998 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+CC=cc
+AR=ar
+RANLIB=echo
+LN_SF=ln -f -s
+RM_F=/bin/rm -f
+
+SUN_CC_FLAGS=-fast -xtarget=ultra -xarch=v9
+SUN_LD_FLAGS=-fast -xtarget=ultra -xarch=v9
+
+# Where the zlib library and include files are located
+# Changing these to ../zlib poses a security risk.  If you want
+# to have zlib in an adjacent directory, specify the full path instead of "..".
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+
+ZLIBLIB=/usr/lib
+ZLIBINC=/usr/include
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=$(SUN_CC_FLAGS) # $(WARNMORE) -g
+ARFLAGS=rc
+LDFLAGS=-L. -R. $(SUN_LD_FLAGS) -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest
+
+include scripts/pnglibconf.mak
+DELETE = $(RM_F)
+DFNFLAGS = $(DEFS) $(CPPFLAGS)
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	@case "`type ld`" in *ucb*) \
+	echo; \
+	echo '## WARNING:'; \
+	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
+	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
+	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
+	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
+	echo '## at all.  If it is, things are likely to break because of'; \
+	echo '## the libucb dependency that is created.'; \
+	echo; \
+	;; \
+	esac
+	$(LD) -G -L$(ZLIBLIB) -R$(ZLIBLIB) -h $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)*
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o      png.pic.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o   pngget.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o   pngmem.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o  pngread.pic.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o   pngrio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o   pngset.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o   pngwio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.aix
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.aix	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.aix	(revision 107811)
@@ -0,0 +1,79 @@
+# makefile for libpng using gcc (generic, static library)
+# Copyright (C) 2000, 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006-2009, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000 Marc O. Gloor (AIX support added, from makefile.gcc)
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = gcc
+LD = $(CC)
+AR = ar
+RANLIB = ranlib
+RM_F = rm -f
+
+LIBNAME = libpng16
+PNGMAJ = 16
+
+WARNMORE =
+CPPFLAGS = -I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS = -O2 -Wall -Wextra -Wundef # $(WARNMORE) -g
+ARFLAGS = rc
+LDFLAGS = -L. -L$(ZLIBLIB) -lpng16 -lz -lm # -g
+
+# File lists
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: $(LIBNAME).a pngtest
+
+include scripts/pnglibconf.mak
+REMOVE = $(RM_F)
+DFNFLAGS = $(DEFS) $(CPPFLAGS)
+
+$(LIBNAME).a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+test: pngtest
+	./pngtest
+
+pngtest: pngtest.o $(LIBNAME).a
+	$(LD) -o $@ pngtest.o $(LDFLAGS)
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o $(LIBNAME).a pngtest pngout.png pnglibconf.h
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.amiga
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.amiga	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.amiga	(revision 107811)
@@ -0,0 +1,56 @@
+# Commodore Amiga Makefile
+# makefile for libpng and SAS C V6.5x compiler
+# Copyright (C) 1995-2000 Wolf Faust
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Location/path of zlib include files
+ZLIB=/zlib
+#compiler
+CC=sc
+#compiler flags
+# WARNING: a bug in V6.51 causes bad code with OPTGO
+#          So use V6.55 or set NOOPTGO!!!!!!!!!
+CFLAGS= NOSTKCHK PARMS=REG OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL\
+	OPTLOOP OPTRDEP=4 OPTDEP=4 OPTCOMP=4 INCLUDEDIR=$(ZLIB) \
+	DEFINE=PNG_INTERNAL
+#linker flags
+LDFLAGS= SD ND BATCH
+#link libs
+LDLIBS= libpng.lib libgz.lib LIB:scm.lib LIB:sc.lib Lib:amiga.lib
+# linker
+LN= slink
+# file deletion command
+RM= delete quiet
+# library (.lib) file creation command
+AR= oml
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+all: libpng.lib pngtest
+
+libpng.lib: $(OBJS)
+-$(RM) libpng.lib
+$(AR) libpng.lib r $(OBJS)
+
+$(OBJS): pngpriv.h png.h pngconf.h pnglibconf.h pnginfo.h pngstruct.h pngdebug.h
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+COPY $(PNGLIBCONF_H_PREBUILT) TO pnglibconf.h
+
+pngtest: pngtest.o libpng.lib
+$(LN) <WITH <
+$(LDFLAGS)
+TO pngtest
+FROM LIB:c.o pngtest.o
+LIB $(LDLIBS)
+<
+
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.atari
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.atari	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.atari	(revision 107811)
@@ -0,0 +1,45 @@
+# makefile for libpng
+# Copyright (C) 2022 Cosmin Truta
+# Copyright (C) 2002, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Modified for LC56/ATARI assumes libz.lib is in same dir and uses default
+# rules for library management
+#
+CPPFLAGS = -I../zlib
+CFLAGS = -O
+LBR = png.lib
+LDFLAGS = -L. -L../zlib -lpng -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = $(LBR)(png.o) $(LBR)(pngerror.o) $(LBR)(pngget.o) $(LBR)(pngmem.o) \
+       $(LBR)(pngpread.o) $(LBR)(pngread.o) $(LBR)(pngrio.o) \
+       $(LBR)(pngrtran.o) $(LBR)(pngrutil.o) $(LBR)(pngset.o) \
+       $(LBR)(pngtrans.o) $(LBR)(pngwio.o) $(LBR)(pngwrite.o) \
+       $(LBR)(pngwtran.o) $(LBR)(pngwutil.o)
+
+all: $(LBR) pngtest.ttp
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+$(LBR): $(OBJS)
+
+$(OBJS): pngpriv.h png.h pngconf.h pnglibconf.h pnginfo.h pngstruct.h pngdebug.h
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	cp $(PNGLIBCONF_H_PREBUILT) $@
+
+pngtest.ttp: pngtest.o $(LBR)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o$@ pngtest.o
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.bc32
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.bc32	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.bc32	(revision 107811)
@@ -0,0 +1,158 @@
+# Makefile for libpng
+# 32-bit Borland C++ (Note: All modules are compiled in C mode)
+# To build the library, do:
+#       "make -fmakefile.bc32"
+#
+# -------------------- 32-bit Borland C++ --------------------
+
+### Absolutely necessary for this makefile to work
+.AUTODEPEND
+
+## Where zlib.h, zconf.h and zlib.lib are
+ZLIB_DIR=..\zlib
+
+## Compiler, linker, librarian and other tools
+CC=bcc32
+LD=bcc32
+LIB=tlib
+CP=copy
+
+# -3 = 386, -4 = 486, -5 = Pentium etc.
+!ifndef TARGET_CPU
+#TARGET_CPU=-6
+!endif
+
+# Use this if you don't want Borland's fancy exception handling
+# (Caution: doesn't work with CBuilderX)
+#NOEHLIB=noeh32.lib
+
+!ifdef DEBUG
+CDEBUG=-v
+LDEBUG=-v
+!else
+CDEBUG=
+LDEBUG=
+!endif
+
+# STACKOFLOW=1
+!ifdef STACKOFLOW
+CDEBUG=$(CDEBUG) -N
+LDEBUG=$(LDEBUG) -N
+!endif
+
+# -O2 optimize for speed
+# -d  merge duplicate strings
+# -k- turn off standard stack frame
+# -w  display all warnings
+CPPFLAGS=-I$(ZLIB_DIR)
+CFLAGS=-O2 -d -k- -w $(TARGET_CPU) $(CDEBUG)
+
+# -M  generate map file
+LDFLAGS=-L$(ZLIB_DIR) -M $(LDEBUG)
+
+## Pre-built configuration
+# See scripts\pnglibconf.mak for more options
+!ifndef PNGLIBCONF_H_PREBUILT
+PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
+!endif
+
+## File lists
+OBJS = \
+	png.obj \
+	pngerror.obj \
+	pngget.obj \
+	pngmem.obj \
+	pngpread.obj \
+	pngread.obj \
+	pngrio.obj \
+	pngrtran.obj \
+	pngrutil.obj \
+	pngset.obj \
+	pngtrans.obj \
+	pngwio.obj \
+	pngwrite.obj \
+	pngwtran.obj \
+	pngwutil.obj
+
+LIBOBJS = \
+	+png.obj \
+	+pngerror.obj \
+	+pngget.obj \
+	+pngmem.obj \
+	+pngpread.obj \
+	+pngread.obj \
+	+pngrio.obj \
+	+pngrtran.obj \
+	+pngrutil.obj \
+	+pngset.obj \
+	+pngtrans.obj \
+	+pngwio.obj \
+	+pngwrite.obj \
+	+pngwtran.obj \
+	+pngwutil.obj
+
+LIBNAME=libpng.lib
+
+## Implicit rules
+# Braces let make "batch" calls to the compiler,
+# 2 calls instead of 12; space is important.
+.c.obj:
+	$(CC) $(CPPFLAGS) $(CFLAGS) -c {$*.c }
+
+.c.exe:
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $*.c \
+	  $(LIBNAME) zlib.lib $(NOEHLIB)
+
+.obj.exe:
+	$(LD) $(LDFLAGS) $*.obj $(LIBNAME) zlib.lib $(NOEHLIB)
+
+## Major targets
+all: libpng pngtest
+
+libpng: $(LIBNAME)
+
+pngtest: pngtest.exe
+
+test: pngtest.exe
+	pngtest
+
+## Minor Targets
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+png.obj:      png.c      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.obj: pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.obj:   pngget.c   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.obj:   pngmem.c   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.obj: pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.obj:  pngread.c  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.obj:   pngrio.c   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.obj: pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.obj: pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.obj:   pngset.c   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.obj: pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.obj:   pngwio.c   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.obj: pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.obj: pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.obj: pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtest.obj:  pngtest.c  png.h pngconf.h pnglibconf.h
+
+$(LIBNAME): $(OBJS)
+	-del $(LIBNAME)
+	$(LIB) $(LIBNAME) @&&|
+$(LIBOBJS), libpng
+|
+
+# Cleanup
+clean:
+	-del pnglibconf.h
+	-del *.obj
+	-del $(LIBNAME)
+	-del pngtest.exe
+	-del *.lst
+	-del *.map
+	-del *.tds
+	-del pngout.png
+
+# End of makefile for libpng
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.beos
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.beos	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.beos	(revision 107811)
@@ -0,0 +1,120 @@
+# makefile for libpng on BeOS x86 ELF with gcc
+# modified from makefile.linux by Sander Stoks
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006, 2008, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1999 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+CC=gcc
+AR=ar
+RANLIB=ranlib
+LN_SF=ln -sf
+CP=cp
+RM_F=/bin/rm -f
+
+# Where the zlib library and include files are located
+ZLIBLIB=/usr/local/lib
+ZLIBINC=/usr/local/include
+
+ALIGN=
+# For i386:
+# ALIGN=-malign-loops=2 -malign-functions=2
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+
+# On BeOS, -O1 is actually better than -O3.  This is a known bug but it's
+# still here in R4.5
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-O1 -funroll-loops $(ALIGN) -Wall -Wextra -Wundef # $(WARNMORE) -g
+ARFLAGS=rc
+# LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng -lz
+LDFLAGS=-L. -Wl,-soname=$(LIBSOMAJ) -L$(ZLIBLIB) -lz # -g
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS)
+
+.SUFFIXES:      .c .o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a $(LIBSO) pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+	cp $(LIBSO)* /boot/home/config/lib
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(CC) -nostart -Wl,-soname,$(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) $(OBJSDLL) $(LDFLAGS)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -L$(ZLIBLIB) -L. -lz -lpng16 -o pngtest pngtest.o
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o      png.pic.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o   pngget.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o   pngmem.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o  pngread.pic.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o   pngrio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o   pngset.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o   pngwio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.clang
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.clang	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.clang	(revision 107811)
@@ -0,0 +1,92 @@
+# makefile for libpng using clang (generic, static library)
+# Copyright (C) 2000, 2014, 2019-2024 Cosmin Truta
+# Copyright (C) 2008, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = clang
+LD = $(CC)
+AR = ar
+RANLIB = ranlib
+CP = cp
+RM_F = rm -f
+
+# Compiler and linker flags
+NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
+	-DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+WARNMORE = -Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+DEFS = $(NOHWOPT)
+CPPFLAGS = -I$(ZLIBINC) $(DEFS) # -DPNG_DEBUG=5
+CFLAGS = -O2 -Wall -Wextra -Wundef # $(WARNMORE) -g
+ARFLAGS = rc
+LDFLAGS = -L$(ZLIBLIB) # -g
+LIBS = -lz -lm
+
+# File extensions
+EXEEXT =
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# File lists
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+all: static
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+static: libpng.a pngtest$(EXEEXT)
+
+shared:
+	@echo This is a generic makefile that cannot create shared libraries.
+	@echo Please use a configuration that is specific to your platform.
+	@false
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+test: pngtest$(EXEEXT)
+	./pngtest$(EXEEXT)
+
+pngtest$(EXEEXT): pngtest.o libpng.a
+	$(LD) $(LDFLAGS) -o $@ pngtest.o libpng.a $(LIBS)
+
+clean:
+	$(RM_F) *.o libpng.a pngtest$(EXEEXT) pngout.png pnglibconf.h
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.darwin
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.darwin	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.darwin	(revision 107811)
@@ -0,0 +1,118 @@
+# makefile for libpng on Darwin / macOS
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2004, 2006, 2008, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 2001 Christoph Pfisterer
+# derived from makefile.linux:
+#  Copyright (C) 1998, 1999 Greg Roelofs
+#  Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Where the zlib library and include files are located
+ZLIBLIB=/usr/lib
+ZLIBINC=/usr/include
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).dylib
+LIBSOMAJ=$(LIBNAME).$(PNGMAJ).dylib
+
+# Utilities:
+CC=cc
+AR=ar
+RANLIB=ranlib
+LN_SF=ln -sf
+CP=cp
+RM_F=rm -f
+
+NOHWOPT=-DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
+        -DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+DEFS=$(NOHWOPT)
+CPPFLAGS=-I$(ZLIBINC) $(DEFS)
+CFLAGS=-O3 -funroll-loops -Wall -Wextra -Wundef
+ARFLAGS=rc
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# File lists
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fno-common -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(CC) -dynamiclib \
+	 -current_version 16 -compatibility_version 16 \
+	 -o $(LIBSOMAJ) \
+	 $(OBJSDLL) -L$(ZLIBLIB) -lz
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBNAME).*dylib pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o      png.pic.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o   pngget.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o   pngmem.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o  pngread.pic.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o   pngrio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o   pngset.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o   pngwio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.dec
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.dec	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.dec	(revision 107811)
@@ -0,0 +1,103 @@
+# makefile for libpng on DEC Alpha Unix
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2000-2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+CC=cc
+AR=ar
+RANLIB=ranlib
+LN_SF=ln -f -s
+CP=cp
+RM_F=/bin/rm -f
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-std -w1 -O # -g
+ARFLAGS=rc
+LDFLAGS=-L$(ZLIBLIB) -rpath $(ZLIBLIB) libpng.a -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: $(LIBSO) libpng.a pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJS)
+	$(CC) -shared -o $@ $(OBJS) -L$(ZLIBLIB) -soname $(LIBSOMAJ)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.dj2
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.dj2	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.dj2	(revision 107811)
@@ -0,0 +1,73 @@
+# DJGPP (DOS gcc) makefile for libpng
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006, 2009-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+CC=gcc
+AR=ar
+RANLIB=ranlib
+CPPFLAGS=-I../zlib -DPNG_NO_SNPRINTF
+CFLAGS=-O
+ARFLAGS=rc
+LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
+
+CP=cp
+RM_F=rm -f
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+	coff2exe pngtest
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.freebsd
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.freebsd	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.freebsd	(revision 107811)
@@ -0,0 +1,53 @@
+# makefile for libpng under FreeBSD
+# Copyright (C) 2020-2022 Cosmin Truta
+# Copyright (C) 2014 Glenn Randers-Pehrson and Andrey A. Chernov
+# Copyright (C) 2002, 2007, 2009 Glenn Randers-Pehrson and Andrey A. Chernov
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+LIB=		png
+SHLIB_VER=	16
+SHLIB_MAJOR=	${SHLIB_VER}
+SHLIB_MINOR=	0
+
+ZLIBLIB=	/usr/lib
+ZLIBINC=	/usr/include
+
+LDADD+=		-lm -lz
+#LDADD+=	-lm -lz -lssp_nonshared   # for OSVERSION < 800000 ?
+
+DPADD+=		${LIBM} ${LIBZ}
+
+CPPFLAGS+=	-I. -I${ZLIBINC}
+CFLAGS+=	-Wall -Wextra -Wundef
+LDFLAGS+=	-L. -L${ZLIBLIB}
+
+CLEANFILES+=	pngtest pngtest.o pngout.png
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt
+
+SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
+	pngread.c pngrio.c pngrtran.c pngrutil.c pngset.c \
+	pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c
+
+.c.o:
+	${CC} -c ${CPPFLAGS} ${CFLAGS} -o $@ $<
+
+pnglibconf.h:	${PNGLIBCONF_H_PREBUILT}
+	cp ${PNGLIBCONF_H_PREBUILT} $@
+
+pngtest:	pngtest.o libpng.a
+	${CC} ${LDFLAGS} -static -o pngtest pngtest.o -lpng ${LDADD}
+
+test:	pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+.include <bsd.lib.mk>
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.gcc
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.gcc	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.gcc	(revision 107811)
@@ -0,0 +1,92 @@
+# makefile for libpng using gcc (generic, static library)
+# Copyright (C) 2000, 2014, 2019-2024 Cosmin Truta
+# Copyright (C) 2008, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = gcc
+LD = $(CC)
+AR = ar
+RANLIB = ranlib
+CP = cp
+RM_F = rm -f
+
+# Compiler and linker flags
+NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
+	-DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+WARNMORE = -Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+DEFS = $(NOHWOPT)
+CPPFLAGS = -I$(ZLIBINC) $(DEFS) # -DPNG_DEBUG=5
+CFLAGS = -O2 -Wall -Wextra -Wundef # $(WARNMORE) -g
+ARFLAGS = rc
+LDFLAGS = -L$(ZLIBLIB) # -g
+LIBS = -lz -lm
+
+# File extensions
+EXEEXT =
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# File lists
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+all: static
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+static: libpng.a pngtest$(EXEEXT)
+
+shared:
+	@echo This is a generic makefile that cannot create shared libraries.
+	@echo Please use a configuration that is specific to your platform.
+	@false
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+test: pngtest$(EXEEXT)
+	./pngtest$(EXEEXT)
+
+pngtest$(EXEEXT): pngtest.o libpng.a
+	$(LD) $(LDFLAGS) -o $@ pngtest.o libpng.a $(LIBS)
+
+clean:
+	$(RM_F) *.o libpng.a pngtest$(EXEEXT) pngout.png pnglibconf.h
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.hp64
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.hp64	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.hp64	(revision 107811)
@@ -0,0 +1,120 @@
+# makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 1999-2002, 2006, 2009, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42
+# Contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Where the zlib library and include files are located
+ZLIBLIB=/opt/zlib/lib
+ZLIBINC=/opt/zlib/include
+
+# Note that if you plan to build a libpng shared library, zlib must also
+# be a shared library, which zlib's configure does not do.  After running
+# zlib's configure, edit the appropriate lines of makefile to read:
+#   CFLAGS=-O1 -DHAVE_UNISTD -DUSE_MAP -fPIC \
+#   LDSHARED=ld -b
+#   SHAREDLIB=libz.sl
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).sl
+LIBSOMAJ=$(LIBNAME).sl.$(PNGMAJ)
+
+# Utilities:
+CC=cc
+AR=ar
+RANLIB=ranlib
+LN_SF=ln -sf
+CP=cp
+RM_F=/bin/rm -f
+
+CPPFLAGS=-I$(ZLIBINC) \
+        -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -DHAVE_UNISTD_H -DUSE_MMAP
+CFLAGS=-O -Ae -Wl,+vnocompatwarnings +DD64 +Z
+# Caution: be sure you have built zlib with the same CFLAGS.
+CCFLAGS=-O -Ae -Wl,+vnocompatwarnings +DD64 +Z
+ARFLAGS=rc
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:	.c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) +z -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(LD) -b +s \
+	+h $(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.hpgcc
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.hpgcc	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.hpgcc	(revision 107811)
@@ -0,0 +1,117 @@
+# makefile for libpng on HP-UX using GCC with the HP ANSI/C linker.
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006-2008, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 2001, Laurent faillie
+# Copyright (C) 1998, 1999 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).sl
+LIBSOMAJ=$(LIBNAME).sl.$(PNGMAJ)
+
+# Utilities:
+CC=gcc
+AR=ar
+RANLIB=ranlib
+LD=ld
+LN_SF=ln -sf
+CP=cp
+RM_F=/bin/rm -f
+
+# Where the zlib library and include files are located
+ZLIBLIB=/opt/zlib/lib
+ZLIBINC=/opt/zlib/include
+
+# Note that if you plan to build a libpng shared library, zlib must also
+# be a shared library, which zlib's configure does not do.  After running
+# zlib's configure, edit the appropriate lines of makefile to read:
+#   CFLAGS=-O1 -DHAVE_UNISTD -DUSE_MAP -fPIC \
+#   LDSHARED=ld -b
+#   SHAREDLIB=libz.sl
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-O3 -funroll-loops -Wall -Wextra -Wundef # $(WARNMORE) -g
+ARFLAGS=rc
+#LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng16 -lz -lm # -g
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz -lm # -g
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(LD) -b +s \
+	+h $(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o      png.pic.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o   pngget.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o   pngmem.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o  pngread.pic.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o   pngrio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o   pngset.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o   pngwio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.hpux
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.hpux	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.hpux	(revision 107811)
@@ -0,0 +1,119 @@
+# makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 1999-2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42
+# Contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Where the zlib library and include files are located
+ZLIBLIB=/opt/zlib/lib
+ZLIBINC=/opt/zlib/include
+
+# Note that if you plan to build a libpng shared library, zlib must also
+# be a shared library, which zlib's configure does not do.  After running
+# zlib's configure, edit the appropriate lines of makefile to read:
+#   CPPFLAGS=-DHAVE_UNISTD -DUSE_MAP
+#   CFLAGS=-O1 -fPIC
+#   LDSHARED=ld -b
+#   SHAREDLIB=libz.sl
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).sl
+LIBSOMAJ=$(LIBNAME).sl.$(PNGMAJ)
+
+# Utilities:
+CC=cc
+AR=ar
+RANLIB=ranlib
+LN_SF=ln -sf
+RM_F=/bin/rm -f
+
+CPPFLAGS=-I$(ZLIBINC)
+CFLAGS=-O -Ae +DA1.1 +DS2.0
+# Caution: be sure you have built zlib with the same CFLAGS.
+CCFLAGS=-O -Ae +DA1.1 +DS2.0
+ARFLAGS=rc
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:	.c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) +z -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(LD) -b +s \
+	+h $(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CCFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.ibmc
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.ibmc	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.ibmc	(revision 107811)
@@ -0,0 +1,90 @@
+# Makefile for libpng (static)
+# IBM C version 3.x for Win32 and OS/2
+# Copyright (C) 2006, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000, 2020 Cosmin Truta
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Notes:
+#   Derived from makefile.std
+#   All modules are compiled in C mode
+#   Tested under Win32, expected to work under OS/2
+#   Can be easily adapted for IBM VisualAge/C++ for AIX
+
+# Location of the zlib library and include files
+ZLIBINC = ../zlib
+ZLIBLIB = ../zlib
+
+# Compiler, linker, lib and other tools
+CC = icc
+LD = ilink
+AR = ilib
+CP = copy
+RM = del
+
+CPPFLAGS = -I$(ZLIBINC)
+CFLAGS = -Mc -O2 -W3
+LDFLAGS =
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# File extensions
+O=.obj
+A=.lib
+E=.exe
+
+# File lists
+OBJS = png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O) \
+       pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O) \
+       pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
+
+LIBS = libpng$(A) $(ZLIBLIB)/zlib$(A)
+
+# Targets
+.c$(O):
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+all: libpng$(A) pngtest$(E)
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng$(A): $(OBJS)
+	$(AR) -out:$@ $(OBJS)
+
+test: pngtest$(E)
+	pngtest$(E)
+
+pngtest: pngtest$(E)
+
+pngtest$(E): pngtest$(O) libpng$(A)
+	$(LD) $(LDFLAGS) pngtest$(O) $(LIBS)
+
+clean:
+	-$(RM) *$(O)
+	-$(RM) libpng$(A)
+	-$(RM) pnglibconf.h
+	-$(RM) pngtest$(E)
+	-$(RM) pngout.png
+
+png$(O):      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread$(O):  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio$(O):   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest$(O):  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.intel
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.intel	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.intel	(revision 107811)
@@ -0,0 +1,118 @@
+# Makefile for libpng
+# Microsoft Visual C++ with Intel C/C++ Compiler 4.0 and later
+
+# Copyright (C) 2006, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2000, Pawel Mrochen, based on makefile.msc which is
+# copyright 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# To use, do "nmake /f scripts\makefile.intel"
+#
+# ------------------- Intel C/C++ Compiler 4.0 and later -------------------
+
+# Where the zlib library and include files are located
+ZLIBLIB=..\zlib
+ZLIBINC=..\zlib
+
+# Target CPU
+CPU=6		# Pentium II
+#CPU=5		# Pentium
+
+# Calling convention
+CALLING=r	# __fastcall
+#CALLING=z	# __stdcall
+#CALLING=d	# __cdecl
+
+# Uncomment next to put error messages in a file
+#ERRFILE=>>pngerrs
+
+# --------------------------------------------------------------------------
+
+CC=icl
+CPPFLAGS=-I$(ZLIBINC)
+CFLAGS=-O2 -G$(CPU)$(CALLING) -Qip -Qunroll4 -nologo
+LD=link
+LDFLAGS=/SUBSYSTEM:CONSOLE /NOLOGO
+CP=cp
+
+# Pre-built configuration
+# See scripts\pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
+
+# File extensions
+O=.obj
+
+# File lists
+OBJS1=png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O)
+OBJS2=pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O)
+OBJS3=pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
+OBJS=$(OBJS1) $(OBJS2) $(OBJS3)
+
+# Targets
+all: test
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngget$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngmem$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+libpng.lib: $(OBJS)
+	if exist libpng.lib del libpng.lib
+	lib /NOLOGO /OUT:libpng.lib $(OBJS)
+
+pngtest.exe: pngtest.obj libpng.lib
+	$(LD) $(LDFLAGS) /OUT:pngtest.exe pngtest.obj libpng.lib $(ZLIBLIB)\zlib.lib
+
+pngtest$(O): png.h pngconf.h pnglibconf.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+test: pngtest.exe
+	pngtest.exe
+
+# End of makefile for libpng
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.linux
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.linux	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.linux	(revision 107811)
@@ -0,0 +1,131 @@
+# makefile for libpng.a and libpng16.so on Linux ELF with gcc
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2014 Greg Roelofs and
+# Glenn Randers-Pehrson
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+CC=gcc
+AR=ar
+RANLIB=ranlib
+LN_SF=ln -sf
+CP=cp
+RM_F=rm -f
+
+# Where the zlib library and include files are located.
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+# Compiler and linker flags
+NOHWOPT=-DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
+	-DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+DEFS=$(NOHWOPT)
+CPPFLAGS=-I$(ZLIBINC) $(DEFS) # -DPNG_DEBUG=5
+CFLAGS=-O3 -funroll-loops -Wall -Wextra -Wundef # $(WARNMORE) -g
+ARFLAGS=rc
+LDFLAGS=-L. -Wl,-rpath,. -L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) -lpng16 -lz -lm # -g
+LDFLAGS_A=-L$(ZLIBLIB) -Wl,-rpath,$(ZLIBLIB) libpng.a -lz -lm # -g
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# File lists
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest pngtest-static
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+pngtest-static: pngtest.o libpng.a
+	$(CC) -o pngtest-static $(CFLAGS) pngtest.o $(LDFLAGS_A)
+
+test: pngtest pngtest-static
+	@echo ""
+	@echo "   Running pngtest dynamically linked with $(LIBSO):"
+	@echo ""
+	./pngtest
+	@echo ""
+	@echo "   Running pngtest statically linked with libpng.a:"
+	@echo ""
+	./pngtest-static
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) $(OBJS) $(OBJSDLL) libpng.a
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+	$(RM_F) pngtest*.o pngtest pngtest-static pngout.png
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o      png.pic.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o   pngget.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o   pngmem.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o  pngread.pic.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o   pngrio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o   pngset.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o   pngwio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.mips
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.mips	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.mips	(revision 107811)
@@ -0,0 +1,71 @@
+# makefile for libpng
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 1998-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+CC=cc
+AR=ar
+#RANLIB=ranlib
+RANLIB=echo
+CPPFLAGS=-I../zlib -DSYSV -Dmips
+CFLAGS=-O -systype sysv -w
+#CFLAGS=-O
+ARFLAGS=rc
+LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	cp $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	rm -f *.o libpng.a pngtest pngout.png pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.msys
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.msys	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.msys	(revision 107811)
@@ -0,0 +1,120 @@
+# makefile for libpng using MSYS/gcc (shared, static library)
+# Copyright (C) 2000, 2019-2024 Cosmin Truta
+# Copyright (C) 2012 Glenn Randers-Pehrson and Christopher M. Wheeler
+#
+# Portions taken from makefile.linux and makefile.gcc:
+# Copyright (C) 2000 Cosmin Truta
+# Copyright (C) 1998, 1999, 2002, 2006, 2008, 2010-2014 Greg Roelofs and
+# Glenn Randers-Pehrson
+# Copyright (C) 1996, 1997 Andreas Dilger
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).dll
+LIBSOMAJ=$(LIBNAME).dll.$(PNGMAJ)
+
+# Where the zlib library and include files are located.
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+ZLIBLIB=/usr/local/lib
+ZLIBINC=/usr/local/include
+
+# Compiler, linker, lib and other tools
+CC = gcc
+LD = $(CC)
+AR = ar
+RANLIB = ranlib
+CP = cp
+RM_F = rm -rf
+LN_SF = ln -sf
+
+CPPFLAGS = # -DPNG_DEBUG=5
+CFLAGS = -O2 -Wall -Wextra -Wundef # -g
+ARFLAGS = rc
+LDFLAGS = # -g
+LIBS = -lz -lm
+
+# File extensions
+EXEEXT = .exe
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+# File lists
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+# Targets
+all: static shared
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+static: libpng.a pngtest$(EXEEXT)
+
+shared: $(LIBSOMAJ)
+	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) -o $(LIBSO)
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ):
+	$(CC) -shared -Wl,-soname,$(LIBSOMAJ) -o $(LIBSOMAJ)
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+test: pngtest$(EXEEXT)
+	./pngtest$(EXEEXT)
+
+pngtest$(EXEEXT): pngtest.o libpng.a
+	$(LD) $(LDFLAGS) -o $@ pngtest.o libpng.a $(LIBS)
+
+clean:
+	$(RM_F) $(OBJS) libpng.a
+	$(RM_F) $(LIBSO) $(LIBSOMAJ) pnglibconf.h
+	$(RM_F) pngtest*.o pngtest$(EXEEXT) pngout.png
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.netbsd
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.netbsd	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.netbsd	(revision 107811)
@@ -0,0 +1,53 @@
+# makefile for libpng on NetBSD
+# Copyright (C) 2020-2022 Cosmin Truta
+# Copyright (C) 2007-2009, 2014 Glenn Randers-Pehrson
+# Copyright (C) 2002 Patrick R.L. Welche
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+SHLIB_MAJOR=	16
+SHLIB_MINOR=	0
+
+LIB=	png
+SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
+	pngread.c pngrio.c pngrtran.c pngrutil.c pngset.c \
+	pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c
+INCS=	png.h pngconf.h pnglibconf.h
+
+CPPFLAGS+=	-I${.CURDIR}
+CFLAGS+=	-Wall -Wextra -Wundef
+
+CLEANFILES+=	pngtest.o pngtest pnglibconf.h
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt
+
+# We should be able to do something like this instead of the manual
+# uncommenting, but it core dumps for me at the moment:
+# .if ${MACHINE_ARCH} == "i386"
+#   MKLINT= no
+# .endif
+
+.c.o:
+	${CC} -c ${CPPFLAGS} ${CFLAGS} -o $@ $<
+
+pnglibconf.h:	${PNGLIBCONF_H_PREBUILT}
+	cp ${PNGLIBCONF_H_PREBUILT} $@
+
+pngtest.o:	pngtest.c
+	${CC} -c ${CPPFLAGS} ${CFLAGS} ${.ALLSRC} -o ${.TARGET}
+
+pngtest:	pngtest.o libpng.a
+	${CC} ${LDFLAGS} ${.ALLSRC} -o ${.TARGET} -lz -lm
+
+test:	pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+.include <bsd.lib.mk>
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.openbsd
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.openbsd	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.openbsd	(revision 107811)
@@ -0,0 +1,47 @@
+# makefile for libpng
+# Copyright (C) 2020-2022 Cosmin Truta
+# Copyright (C) 2007-2009, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+SHLIB_MAJOR=	16
+SHLIB_MINOR=	0
+
+LIB=	png
+SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
+	pngread.c pngrio.c pngrtran.c pngrutil.c pngset.c \
+	pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c
+HDRS=	png.h pngconf.h pnglibconf.h
+
+CPPFLAGS+=	-I${.CURDIR}
+CFLAGS+=	-Wall -Wextra -Wundef
+
+CLEANFILES+=	pngtest.o pngtest pnglibconf.h
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT= scripts/pnglibconf.h.prebuilt
+
+.c.o:
+	${CC} -c ${CPPFLAGS} ${CFLAGS} -o $@ $<
+
+pnglibconf.h:	${PNGLIBCONF_H_PREBUILT}
+	cp ${PNGLIBCONF_H_PREBUILT} $@
+
+pngtest.o:	pngtest.c
+	${CC} -c ${CPPFLAGS} ${CFLAGS} ${.ALLSRC} -o ${.TARGET}
+
+pngtest:	pngtest.o
+	${CC} ${LDFLAGS} ${.ALLSRC} -o ${.TARGET} -L${.OBJDIR} -lpng -lz -lm
+
+test:	pngtest
+	env LD_LIBRARY_PATH="${.OBJDIR}" ./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+.include <bsd.lib.mk>
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.sco
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.sco	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.sco	(revision 107811)
@@ -0,0 +1,114 @@
+# makefile for SCO OSr5  ELF and Unixware 7 with Native cc
+# Contributed by Mike Hopkirk (hops at sco.com) modified from Makefile.lnx
+#   force ELF build dynamic linking, SONAME setting in lib and RPATH in app
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1998 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+CC=cc
+AR=ar
+RANLIB=echo
+LN_SF=ln -f -s
+CP=cp
+RM_F=/bin/rm -f
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+CPPFLAGS=-I$(ZLIBINC)
+CFLAGS=-dy -belf -O3
+ARFLAGS=rc
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng16 -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	$(CC) -G  -Wl,-h,$(LIBSOMAJ) -o $(LIBSOMAJ) \
+	 $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	LD_RUN_PATH=.:$(ZLIBLIB) $(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* pngtest-static pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o      png.pic.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o   pngget.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o   pngmem.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o  pngread.pic.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o   pngrio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o   pngset.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o   pngwio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.sggcc
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.sggcc	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.sggcc	(revision 107811)
@@ -0,0 +1,118 @@
+# makefile for libpng.a and libpng16.so, SGI IRIX with 'cc'
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2001-2002, 2006, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+CC=gcc
+AR=ar
+RANLIB=echo
+LN_SF=ln -sf
+CP=cp
+RM_F=/bin/rm -f
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib32
+#ZLIBINC=/usr/local/include
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+# ABI can be blank to use default for your system, -32, -o32, -n32, or -64
+# See "man abi".  zlib must be built with the same ABI.
+ABI=
+
+WARNMORE=
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=$(ABI) -O $(WARNMORE) -fPIC -mabi=n32 # -g
+ARFLAGS=rc
+LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm # -g
+LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
+	-set_version sgi$(PNGMAJ).0
+# See "man dso" for info about shared objects
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest shared
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+shared: $(LIBSOMAJ)
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJS)
+	$(LDSHARED) -o $@ $(OBJS)
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	echo
+	echo Testing local static library.
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) libpng.a pngtest pngout.png
+	$(RM_F) so_locations $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.sgi
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.sgi	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.sgi	(revision 107811)
@@ -0,0 +1,119 @@
+# makefile for libpng.a and libpng16.so, SGI IRIX with 'cc'
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2001-2002, 2006, 2007, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+CC=cc
+AR=ar
+RANLIB=echo
+LN_SF=ln -sf
+CP=cp
+RM_F=/bin/rm -f
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib32
+#ZLIBINC=/usr/local/include
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+# ABI can be blank to use default for your system, -32, -o32, -n32, or -64
+# See "man abi".  zlib must be built with the same ABI.
+ABI=
+
+WARNMORE=-fullwarn
+# Note: -KPIC is the default anyhow
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+#CFLAGS= $(ABI) -O $(WARNMORE) -KPIC # -g
+CFLAGS=$(ABI) -O $(WARNMORE) # -g
+ARFLAGS=rc
+LDFLAGS_A=$(ABI) -L. -L$(ZLIBLIB) -lpng16 -lz -lm # -g
+LDFLAGS=$(ABI) -L. -L$(ZLIBLIB) -lpng -lz -lm # -g
+LDSHARED=cc $(ABI) -shared -soname $(LIBSOMAJ) \
+	-set_version sgi$(PNGMAJ).0
+# See "man dso" for info about shared objects
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest shared
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJS)
+	$(LDSHARED) -o $@ $(OBJS)
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	echo
+	echo Testing local static library.
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* so_locations pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.so9
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.so9	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.so9	(revision 107811)
@@ -0,0 +1,132 @@
+# makefile for libpng on Solaris 9 (beta) with Forte cc
+# Updated by Chad Schrock for Solaris 9
+# Contributed by William L. Sebok, based on makefile.linux
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006, 2008, 2010-2014 Glenn Randers-Pehrson
+# Copyright (C) 1998-2001 Greg Roelofs
+# Copyright (C) 1996-1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+# gcc 2.95 doesn't work.
+CC=cc
+AR=ar
+RANLIB=echo
+LN_SF=ln -f -s
+CP=cp
+RM_F=/bin/rm -f
+
+# Where the zlib library and include files are located
+# Changing these to ../zlib poses a security risk.  If you want
+# to have zlib in an adjacent directory, specify the full path instead of "..".
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+#Use the preinstalled zlib that comes with Solaris 9:
+ZLIBLIB=/usr/lib
+ZLIBINC=/usr/include
+
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-O3
+ARFLAGS=rc
+LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -KPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	@case "`type ld`" in *ucb*) \
+	echo; \
+	echo '## WARNING:'; \
+	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
+	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
+	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
+	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
+	echo '## at all.  If it is, things are likely to break because of'; \
+	echo '## the libucb dependency that is created.'; \
+	echo; \
+	;; \
+	esac
+	$(LD) -G -h $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o      png.pic.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o   pngget.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o   pngmem.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o  pngread.pic.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o   pngrio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o   pngset.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o   pngwio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.solaris
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.solaris	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.solaris	(revision 107811)
@@ -0,0 +1,131 @@
+# makefile for libpng on Solaris 2.x with gcc
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2004, 2006-2008, 2010-2014 Glenn Randers-Pehrson
+# Contributed by William L. Sebok, based on makefile.linux
+# Copyright (C) 1998 Greg Roelofs
+# Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Library name:
+LIBNAME=libpng16
+PNGMAJ=16
+
+# Shared library names:
+LIBSO=$(LIBNAME).so
+LIBSOMAJ=$(LIBNAME).so.$(PNGMAJ)
+
+# Utilities:
+CC=gcc
+AR=ar
+RANLIB=echo
+LN_SF=ln -f -s
+CP=cp
+RM_F=/bin/rm -f
+
+# Where the zlib library and include files are located
+# Changing these to ../zlib poses a security risk.  If you want
+# to have zlib in an adjacent directory, specify the full path instead of "..".
+#ZLIBLIB=../zlib
+#ZLIBINC=../zlib
+
+ZLIBLIB=/usr/local/lib
+ZLIBINC=/usr/local/include
+
+WARNMORE=-Wwrite-strings -Wpointer-arith -Wshadow \
+	-Wmissing-declarations -Wtraditional -Wcast-align \
+	-Wstrict-prototypes -Wmissing-prototypes # -Wconversion
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-O -Wall -Wextra -Wundef # $(WARNMORE) -g
+ARFLAGS=rc
+LDFLAGS=-L. -R. -L$(ZLIBLIB) -R$(ZLIBLIB) -lpng16 -lz -lm # -g
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+OBJSDLL = $(OBJS:.o=.pic.o)
+
+.SUFFIXES:      .c .o .pic.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+.c.pic.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -fPIC -o $@ $*.c
+
+all: libpng.a $(LIBSO) pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+$(LIBSO): $(LIBSOMAJ)
+	$(LN_SF) $(LIBSOMAJ) $(LIBSO)
+
+$(LIBSOMAJ): $(OBJSDLL)
+	@case "`type ld`" in *ucb*) \
+	echo; \
+	echo '## WARNING:'; \
+	echo '## The commands "CC" and "LD" must NOT refer to /usr/ucb/cc'; \
+	echo '## and /usr/ucb/ld.  If they do, you need to adjust your PATH'; \
+	echo '## environment variable to put /usr/ccs/bin ahead of /usr/ucb.'; \
+	echo '## The environment variable LD_LIBRARY_PATH should not be set'; \
+	echo '## at all.  If it is, things are likely to break because of'; \
+	echo '## the libucb dependency that is created.'; \
+	echo; \
+	;; \
+	esac
+	$(LD) -G -h $(LIBSOMAJ) \
+	 -o $(LIBSOMAJ) $(OBJSDLL)
+
+pngtest: pngtest.o $(LIBSO)
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-static:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+install-shared:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png
+	$(RM_F) $(LIBSO) $(LIBSOMAJ)* pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o      png.pic.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o pngerror.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o   pngget.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o   pngmem.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o pngpread.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o  pngread.pic.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o   pngrio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o pngrtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o pngrutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o   pngset.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o pngtrans.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o   pngwio.pic.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o pngwrite.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o pngwtran.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o pngwutil.pic.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o: png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.std
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.std	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.std	(revision 107811)
@@ -0,0 +1,104 @@
+# makefile for libpng
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+CC = cc
+CPP = $(CC) -E
+LD = $(CC)
+AR = ar
+RANLIB = ranlib
+MV_F = mv -f
+RM_F = rm -f
+AWK = awk
+
+NOHWOPT = -DPNG_ARM_NEON_OPT=0 -DPNG_MIPS_MSA_OPT=0 \
+	-DPNG_POWERPC_VSX_OPT=0 -DPNG_INTEL_SSE_OPT=0
+DFNFLAGS = # DFNFLAGS contains -D options to use in the libpng build
+DFA_EXTRA = # extra files that can be used to control configuration
+CPPFLAGS = -I$(ZLIBINC) $(NOHWOPT) # -DPNG_DEBUG=5
+CFLAGS = -O # -g
+ARFLAGS = rc
+LDFLAGS = -L$(ZLIBLIB) # -g
+LIBS = -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest
+
+# The standard pnglibconf.h exists as scripts/pnglibconf.h.prebuilt,
+# copy this if the following doesn't work.
+pnglibconf.h: pnglibconf.dfn
+	$(RM_F) $@ pnglibconf.c pnglibconf.out pnglibconf.tmp
+	echo '#include "pnglibconf.dfn"' >pnglibconf.c
+	@echo "## If '$(CC) -E' fails, try /lib/cpp (e.g. CPP='/lib/cpp')" >&2
+	$(CPP) $(DFNFLAGS) pnglibconf.c >pnglibconf.out
+	$(AWK) -f scripts/dfn.awk out=pnglibconf.tmp pnglibconf.out >&2
+	$(MV_F) pnglibconf.tmp $@
+
+pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
+	$(RM_F) $@ pnglibconf.pre pnglibconf.tmp
+	@echo "## Calling $(AWK) from scripts/pnglibconf.mak" >&2
+	@echo "## If 'awk' fails, try a better awk (e.g. AWK='nawk')" >&2
+	$(AWK) -f scripts/options.awk out=pnglibconf.pre\
+	    version=search pngconf.h scripts/pnglibconf.dfa\
+	    pngusr.dfa $(DFA_XTRA) >&2
+	$(AWK) -f scripts/options.awk out=pnglibconf.tmp pnglibconf.pre >&2
+	$(MV_F) pnglibconf.tmp $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(LD) $(LDFLAGS) -o $@ pngtest.o libpng.a $(LIBS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.h
+	$(RM_F) pnglibconf.c pnglibconf.dfn pnglibconf.out pnglibconf.pre
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.sunos
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.sunos	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.sunos	(revision 107811)
@@ -0,0 +1,78 @@
+# makefile for libpng
+# Copyright (C) 2020-2024 Cosmin Truta
+# Copyright (C) 2002, 2006, 2014 Glenn Randers-Pehrson
+# Copyright (C) 1995 Guy Eric Schalnat, Group 42, Inc.
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# Where the zlib library and include files are located
+#ZLIBLIB=/usr/local/lib
+#ZLIBINC=/usr/local/include
+ZLIBLIB=../zlib
+ZLIBINC=../zlib
+
+CC=gcc
+AR=ar
+RANLIB=ranlib
+CP=cp
+RM_F=/bin/rm -f
+
+CPPFLAGS=-I$(ZLIBINC) # -DPNG_DEBUG=5
+CFLAGS=-O
+ARFLAGS=rc
+LDFLAGS=-L. -L$(ZLIBLIB) -lpng -lz -lm
+
+# Pre-built configuration
+# See scripts/pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts/pnglibconf.h.prebuilt
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
+all: libpng.a pngtest
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+libpng.a: $(OBJS)
+	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(RANLIB) $@
+
+pngtest: pngtest.o libpng.a
+	$(CC) -o pngtest $(CFLAGS) pngtest.o $(LDFLAGS)
+
+test: pngtest
+	./pngtest
+
+install:
+	@echo "The $@ target is no longer supported by this makefile."
+	@false
+
+clean:
+	$(RM_F) *.o libpng.a pngtest pngout.png pnglibconf.h
+
+# DO NOT DELETE THIS LINE -- make depend depends on it.
+
+png.o:      png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngerror.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngget.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngmem.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngread.o:  png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngset.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngtrans.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwio.o:   png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+
+pngtest.o:  png.h pngconf.h pnglibconf.h
Index: /trunk/src/libs/libpng-1.6.45/scripts/makefile.vcwin32
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makefile.vcwin32	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makefile.vcwin32	(revision 107811)
@@ -0,0 +1,112 @@
+# makefile for libpng
+# Copyright (C) 1998 Tim Wegner
+# Copyright (C) 2006,2009,2011,2014 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+#
+# Assumes that zlib.lib, zconf.h, and zlib.h have been copied to ..\zlib
+# To use, do "nmake /f scripts\makefile.vcwin32"
+
+# -------- Microsoft Visual C++ 2.0 and later --------
+
+# Compiler, linker, librarian and other tools
+CC = cl
+LD = link
+AR = lib
+CPPFLAGS = -I..\zlib
+CFLAGS  = -nologo -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -MD -O2 -W3
+LDFLAGS = -nologo
+ARFLAGS = -nologo
+CP = copy
+RM = del
+
+# Uncomment next to put error messages in a file
+#ERRFILE= >> pngerrs.log
+
+# Pre-built configuration
+# See scripts\pnglibconf.mak for more options
+PNGLIBCONF_H_PREBUILT = scripts\pnglibconf.h.prebuilt
+
+# File extensions
+O = .obj
+
+# File lists
+OBJS1 = png$(O) pngerror$(O) pngget$(O) pngmem$(O) pngpread$(O)
+OBJS2 = pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) pngset$(O)
+OBJS3 = pngtrans$(O) pngwio$(O) pngwrite$(O) pngwtran$(O) pngwutil$(O)
+OBJS  = $(OBJS1) $(OBJS2) $(OBJS3)
+
+# Targets
+all: libpng.lib
+
+pnglibconf.h: $(PNGLIBCONF_H_PREBUILT)
+	$(CP) $(PNGLIBCONF_H_PREBUILT) $@
+
+png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngget$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngmem$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+libpng.lib: $(OBJS)
+	-$(RM) $@
+	$(AR) $(ARFLAGS) -out:$@ $(OBJS) $(ERRFILE)
+
+pngtest.exe: pngtest$(O) libpng.lib
+	$(LD) $(LDFLAGS) -out:$@ pngtest$(O) libpng.lib ..\zlib\zlib.lib $(ERRFILE)
+
+pngtest$(O): png.h pngconf.h pnglibconf.h
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) $*.c $(ERRFILE)
+
+test: pngtest.exe
+	pngtest.exe
+
+clean:
+	-$(RM) *$(O)
+	-$(RM) libpng.lib
+	-$(RM) pnglibconf.h
+	-$(RM) pngtest.exe
+	-$(RM) pngout.png
+
+# End of makefile for libpng
Index: /trunk/src/libs/libpng-1.6.45/scripts/makevms.com
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/makevms.com	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/makevms.com	(revision 107811)
@@ -0,0 +1,142 @@
+$! make libpng under VMS
+$!
+$!
+$! Check for MMK/MMS
+$!
+$! This procedure accepts one parameter (contrib), which causes it to build
+$! the programs from the contrib directory instead of libpng.
+$!
+$ p1 = f$edit(p1,"UPCASE")
+$ if p1 .eqs. "CONTRIB"
+$ then
+$   set def [.contrib.gregbook]
+$   @makevms
+$   set def [-.pngminus]
+$   @makevms
+$   set def [--]
+$   exit
+$ endif
+$ Make = ""
+$ If F$Search ("Sys$System:MMS.EXE") .nes. "" Then Make = "MMS"
+$ If F$Type (MMK) .eqs. "STRING" Then Make = "MMK"
+$!
+$! Look for the compiler used
+$!
+$ zlibsrc = "[-.zlib]"
+$ ccopt="/include=''zlibsrc'"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$!
+$! Build the thing plain or with mms/mmk
+$!
+$ write sys$output "Compiling Libpng sources ..."
+$ if make.eqs.""
+$  then
+$   dele pngtest.obj;*
+$   CALL MAKE png.OBJ "cc ''CCOPT' png" -
+	png.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngset.OBJ "cc ''CCOPT' pngset" -
+	pngset.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngget.OBJ "cc ''CCOPT' pngget" -
+	pngget.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngread.OBJ "cc ''CCOPT' pngread" -
+	pngread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngpread.OBJ "cc ''CCOPT' pngpread" -
+	pngpread.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngrtran.OBJ "cc ''CCOPT' pngrtran" -
+	pngrtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngrutil.OBJ "cc ''CCOPT' pngrutil" -
+	pngrutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngerror.OBJ "cc ''CCOPT' pngerror" -
+	pngerror.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngmem.OBJ "cc ''CCOPT' pngmem" -
+	pngmem.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngrio.OBJ "cc ''CCOPT' pngrio" -
+	pngrio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngwio.OBJ "cc ''CCOPT' pngwio" -
+	pngwio.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngtrans.OBJ "cc ''CCOPT' pngtrans" -
+	pngtrans.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngwrite.OBJ "cc ''CCOPT' pngwrite" -
+	pngwrite.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngwtran.OBJ "cc ''CCOPT' pngwtran" -
+	pngwtran.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   CALL MAKE pngwutil.OBJ "cc ''CCOPT' pngwutil" -
+	pngwutil.c png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+$   write sys$output "Building Libpng ..."
+$   CALL MAKE libpng.OLB "lib/crea libpng.olb *.obj" *.OBJ
+$   write sys$output "Building pngtest..."
+$   CALL MAKE pngtest.OBJ "cc ''CCOPT' pngtest" -
+	pngtest.c png.h pngconf.h pnglibconf.h
+$   call make pngtest.exe -
+	"LINK pngtest,libpng.olb/lib,''zlibsrc'libz.olb/lib" -
+	pngtest.obj libpng.olb
+$   write sys$output "Testing Libpng..."
+$   run pngtest
+$  else
+$   if f$search("DESCRIP.MMS") .eqs. "" then copy/nolog [.SCRIPTS]DESCRIP.MMS []
+$   'make'/macro=('comp',zlibsrc='zlibsrc')
+$  endif
+$ write sys$output "Libpng build completed"
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE
Index: /trunk/src/libs/libpng-1.6.45/scripts/options.awk
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/options.awk	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/options.awk	(revision 107811)
@@ -0,0 +1,903 @@
+#!/bin/awk -f
+
+# scripts/options.awk - library build configuration control
+#
+# Copyright (c) 1998-2014 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# The output of this script is written to the file given by
+# the variable 'out'.  The script is run twice, once with
+# an intermediate output file, 'options.tmp' then again on
+# that file to produce the final output:
+#
+#  awk -f scripts/options.awk out=options.tmp scripts/options.dfa 1>&2
+#  awk -f scripts/options.awk out=options.dfn options.tmp 1>&2
+#
+# Some options may be specified on the command line:
+#
+#  deb=1            Causes debugging to be output
+#  logunsupported=1 Causes all options to be recorded in the output
+#  everything=off   Causes all options to be disabled by default
+#  everything=on    Causes all options to be enabled by default
+#
+# If awk fails on your platform, try nawk instead.
+#
+# These options may also be specified in the original input file (and
+# are copied to the preprocessed file).
+
+BEGIN{
+   out=""                       # intermediate, preprocessed, file
+   pre=-1                       # preprocess (first line)
+   version="libpng version unknown" # version information
+   version_file=""              # where to find the version
+   err=0                        # in-line exit sets this
+   # The following definitions prevent the C preprocessor noticing the lines
+   # that will be in the final output file.  Some C preprocessors tokenise
+   # the lines, for example by inserting spaces around operators, and all
+   # C preprocessors notice lines that start with '#', most remove comments.
+   # The technique adopted here is to make the final output lines into
+   # C strings (enclosed in double quotes), preceded by PNG_DFN.  As a
+   # consequence the output cannot contain a 'raw' double quote - instead put
+   # @' in, this will be replaced by a single " afterward.  See the parser
+   # script dfn.awk for more capabilities (not required here).  Note that if
+   # you need a " in a 'setting' in pnglibconf.dfa it must also be @'!
+   dq="@'"                      # For a single double quote
+   start=" PNG_DFN \""          # Start stuff to output (can't contain a "!)
+   end="\" "                    # End stuff to output
+   subs="@\" "                  # Substitute start (substitute a C macro)
+   sube=" \"@"                  # Substitute end
+   comment=start "/*"           # Comment start
+   cend="*/" end                # Comment end
+   def=start "#define PNG_"     # Arbitrary define
+   sup="_SUPPORTED" end         # end supported option
+   und=comment "#undef PNG_"    # Unsupported option
+   une="_SUPPORTED" cend        # end unsupported option
+   error=start "ERROR:"         # error message, terminate with 'end'
+
+   # Variables
+   deb=0                        # debug - set on command line
+   everything=""                # do not override defaults
+   logunsupported=0             # write unsupported options too
+
+   # Precreate arrays
+   # for each option:
+   option[""] = ""    # list of all options: default enabled/disabled
+   done[""] = 1       # marks option as having been output
+   requires[""] = ""  # requires by option
+   iffs[""] = ""      # if by option
+   enabledby[""] = "" # options that enable it by option
+   sets[""] = ""      # settings set by each option
+   setval[""] = ""    # value to set (indexed: 'option sets[option]')
+   # for each setting:
+   setting[""] = ""   # requires by setting
+   defaults[""] = ""  # used for a defaulted value
+   doneset[""] = 1    # marks setting as having been output
+   r[""] = ""         # Temporary array
+
+   # For decorating the output file
+   protect = ""
+}
+
+# The output file must be specified before any input:
+out == "" {
+   print "out=output.file must be given on the command line"
+   err = 1
+   exit 1
+}
+
+# The very first line indicates whether we are reading pre-processed
+# input or not, this must come *first* because 'PREPROCESSED' needs
+# to be the very first line in the temporary file.
+pre == -1{
+   if ($0 == "PREPROCESSED") {
+      pre = 0
+      next
+   } else {
+      pre = 1
+      print "PREPROCESSED" >out
+      # And fall through to continue processing
+   }
+}
+
+# While pre-processing if version is set to "search" look for a version string
+# in the following file.
+pre && version == "search" && version_file == ""{
+   version_file = FILENAME
+}
+
+pre && version == "search" && version_file != FILENAME{
+   print "version string not found in", version_file
+   err = 1
+   exit 1
+}
+
+pre && version == "search" && $0 ~ /^ \* libpng version/{
+   version = substr($0, 4)
+   print "version =", version >out
+   next
+}
+
+pre && FILENAME == version_file{
+   next
+}
+
+# variable=value
+#   Sets the given variable to the given value (the syntax is fairly
+#   free form, except for deb (you are expected to understand how to
+#   set the debug variable...)
+#
+#   This happens before the check on 'pre' below skips most of the
+#   rest of the actions, so the variable settings happen during
+#   preprocessing but are recorded in the END action too.  This
+#   allows them to be set on the command line too.
+$0 ~ /^[ 	]*version[ 	]*=/{
+   sub(/^[  ]*version[  ]*=[  ]*/, "")
+   version = $0
+   next
+}
+$0 ~ /^[ 	]*everything[ 	=]*off[ 	]*$/{
+   everything = "off"
+   next
+}
+$0 ~ /^[ 	]*everything[ 	=]*on[ 	]*$/{
+   everything = "on"
+   next
+}
+$0 ~ /^[ 	]*logunsupported[ 	=]*0[ 	]*$/{
+   logunsupported = 0
+   next
+}
+$0 ~ /^[ 	]*logunsupported[ 	=]*1[ 	]*$/{
+   logunsupported = 1
+   next
+}
+$1 == "deb" && $2 == "=" && NF == 3{
+   deb = $3
+   next
+}
+
+# Preprocessing - this just copies the input file with lines
+# that need preprocessing (just chunk at present) expanded
+# The bare "pre" instead of "pre != 0" crashes under Sunos awk
+pre && $1 != "chunk"{
+   print >out
+   next
+}
+
+# The first characters of the line determine how it is processed,
+# leading spaces are ignored.  In general tokens that are not
+# keywords are the names of options.  An option 'name' is
+# controlled by the definition of the corresponding macros:
+#
+#   PNG_name_SUPPORTED    The option is turned on
+#   PNG_NO_name
+#   PNG_NO_name_SUPPORTED If the first macro is not defined
+#                         either of these will turn the option off
+#
+# If none of these macros are defined the option is turned on, unless
+# the keyword 'off' is given in a line relating to the option.  The
+# keyword 'on' can also be given, but it will be ignored (since it is
+# the default.)
+#
+# In the syntax below a 'name' is indicated by "NAME", other macro
+# values are indicated by "MACRO", as with "NAME" the leading "PNG_"
+# is omitted, but in this case the "NO_" prefix and the "_SUPPORTED"
+# suffix are never used.
+#
+# Each line is introduced by a keyword - the first non-space characters
+# on the line.  A line starting with a '#' is a comment - it is totally
+# ignored.  Keywords are as follows, a NAME, is simply a macro name
+# without the leading PNG_, PNG_NO_ or the trailing _SUPPORTED.
+
+$1 ~ /^#/ || $0 ~ /^[ 	]*$/{
+   next
+}
+
+# com <comment>
+#   The whole line is placed in the output file as a comment with
+#   the preceding 'com' removed
+$1 == "com"{
+   if (NF > 1) {
+      # sub(/^[ 	]*com[ 	]*/, "")
+      $1 = ""
+      print comment $0, cend >out
+   } else
+      print start end >out
+   next
+}
+
+# version
+#   Inserts a version comment
+$1 == "version" && NF == 1{
+   if (version == "") {
+      print "ERROR: no version string set"
+      err = 1 # prevent END{} running
+      exit 1
+   }
+
+   print comment, version, cend >out
+   next
+}
+
+# file output input protect
+#   Informational: the official name of the input file (without
+#   make generated local directories), the official name of the
+#   output file and, if required, a name to use in a protection
+#   macro for the contents.
+$1 == "file" && NF >= 2{
+   print comment, $2, cend >out
+   print comment, "Machine generated file: DO NOT EDIT", cend >out
+   if (NF >= 3)
+      print comment, "Derived from:", $3, cend >out
+   protect = $4
+   if (protect != "") {
+      print start "#ifndef", protect end >out
+      print start "#define", protect end >out
+   }
+   next
+}
+
+# option NAME ( (requires|enables|if) NAME* | on | off | disabled |
+#                sets SETTING VALUE+ )*
+#
+#   Declares an option 'NAME' and describes its default setting (disabled)
+#   and its relationship to other options.  The option is disabled
+#   unless *all* the options listed after 'requires' are set and at
+#   least one of the options listed after 'if' is set.  If the
+#   option is set then it turns on all the options listed after 'enables'.
+#
+#   Note that "enables" takes priority over the required/if/disabled/off
+#   setting of the target option.
+#
+#   The definition file may list an option as 'disabled': off by default,
+#   otherwise the option is enabled: on by default.  A later (and it must
+#   be later) entry may turn an option on or off explicitly.
+
+$1 == "option" && NF >= 2{
+   opt = $2
+   sub(/,$/,"",opt)
+   onoff = option[opt]  # records current (and the default is "", enabled)
+   key = ""
+   istart = 3
+   do {
+      if (istart == 1) {     # continuation line
+         val = getline
+
+         if (val != 1) { # error reading it
+            if (val == 0)
+               print "option", opt ": ERROR: missing continuation line"
+            else
+               print "option", opt ": ERROR: error reading continuation line"
+
+            # This is a hard error
+            err = 1 # prevent END{} running
+            exit 1
+         }
+      }
+
+      for (i=istart; i<=NF; ++i) {
+         val=$(i)
+         sub(/,$/,"",val)
+         if (val == "on" || val == "off" || val == "disabled" || val =="enabled") {
+            key = ""
+            if (onoff != val) {
+               # on or off can zap disabled or enabled:
+               if (onoff == "" || (onoff == "disabled" || onoff == "enabled") &&
+                   (val == "on" || val == "off")) {
+                  # It's easy to mis-spell the option when turning it
+                  # on or off, so warn about it here:
+                  if (onoff == "" && (val == "on" || val == "off")) {
+                     print "option", opt ": ERROR: turning unrecognized option", val
+                     # For the moment error out - it is safer
+                     err = 1 # prevent END{} running
+                     exit 1
+                  }
+                  onoff = val
+               } else {
+                  # Print a message, otherwise the error
+                  # below is incomprehensible
+                  print "option", opt ": currently", onoff ": attempt to turn", val
+                  break
+               }
+            }
+         } else if (val == "requires" || val == "if" || val == "enables" || val =="sets") {
+            key = val
+         } else if (key == "requires") {
+            requires[opt] = requires[opt] " " val
+         } else if (key == "if") {
+            iffs[opt] = iffs[opt] " " val
+         } else if (key == "enables") {
+            enabledby[val] = enabledby[val] " " opt
+         } else if (key == "sets") {
+            sets[opt] = sets[opt] " " val
+            key = "setval"
+            set = val
+         } else if (key == "setval") {
+            setval[opt " " set] = setval[opt " " set] " " val
+         } else
+            break # bad line format
+      }
+
+      istart = 1
+   } while (i > NF && $0 ~ /,$/)
+
+   if (i > NF) {
+      # Set the option, defaulting to 'enabled'
+      if (onoff == "") onoff = "enabled"
+      option[opt] = onoff
+      next
+   }
+   # Else fall through to the error handler
+}
+
+# chunk NAME [requires OPT] [enables LIST] [on|off|disabled]
+#   Expands to the 'option' settings appropriate to the reading and
+#   writing of an ancillary PNG chunk 'NAME':
+#
+#   option READ_NAME requires READ_ANCILLARY_CHUNKS [READ_OPT]
+#   option READ_NAME enables NAME LIST
+#   [option READ_NAME off]
+#   option WRITE_NAME requires WRITE_ANCILLARY_CHUNKS [WRITE_OPT]
+#   option WRITE_NAME enables NAME LIST
+#   [option WRITE_NAME off]
+
+pre != 0 && $1 == "chunk" && NF >= 2{
+   # 'chunk' is handled on the first pass by writing appropriate
+   # 'option' lines into the intermediate file.
+   opt = $2
+   sub(/,$/,"",opt)
+   onoff = ""
+   reqread = ""
+   reqwrite = ""
+   enables = ""
+   req = 0
+   istart = 3
+   do {
+      if (istart == 1) {     # continuation line
+         val = getline
+
+         if (val != 1) { # error reading it
+            if (val == 0)
+               print "chunk", opt ": ERROR: missing continuation line"
+            else
+               print "chunk", opt ": ERROR: error reading continuation line"
+
+            # This is a hard error
+            err = 1 # prevent END{} running
+            exit 1
+         }
+      }
+
+      # read the keywords/additional OPTS
+      for (i=istart; i<=NF; ++i) {
+         val = $(i)
+         sub(/,$/,"",val)
+         if (val == "on" || val == "off" || val == "disabled") {
+            if (onoff != val) {
+               if (onoff == "")
+                  onoff = val
+               else
+                  break # on/off conflict
+            }
+            req = 0
+         } else if (val == "requires")
+            req = 1
+         else if (val == "enables")
+            req = 2
+         else if (req == 1){
+            reqread = reqread " READ_" val
+            reqwrite = reqwrite " WRITE_" val
+         } else if (req == 2)
+            enables = enables " " val
+         else
+            break # bad line: handled below
+      }
+
+      istart = 1
+   } while (i > NF && $0 ~ /,$/)
+
+   if (i > NF) {
+      # Output new 'option' lines to the intermediate file (out)
+      print "option READ_" opt, "requires READ_ANCILLARY_CHUNKS" reqread,
+            "enables", opt enables , onoff >out
+      print "option WRITE_" opt, "requires WRITE_ANCILLARY_CHUNKS" reqwrite,
+            "enables", opt enables, onoff >out
+      next
+   }
+   # Else hit the error handler below - bad line format!
+}
+
+# setting MACRO ( requires MACRO* )* [ default VALUE ]
+#   Behaves in a similar way to 'option' without looking for NO_ or
+#   _SUPPORTED; the macro is enabled if it is defined so long as all
+#   the 'requires' macros are also defined.  The definitions may be
+#   empty, an error will be issued if the 'requires' macros are
+#   *not* defined.  If given the 'default' value is used if the
+#   macro is not defined.  The default value will be re-tokenised.
+#   (BTW: this is somewhat restrictive, it mainly exists for the
+#   support of non-standard configurations and numeric parameters,
+#   see the uses in scripts/options.dat
+
+$1 == "setting" && (NF == 2 || NF >= 3 && ($3 == "requires" || $3 == "default")){
+   reqs = ""
+   deflt = ""
+   isdef = 0
+   key = ""
+   for (i=3; i<=NF; ++i)
+      if ($(i) == "requires" || $(i) == "default") {
+         key = $(i)
+         if (key == "default") isdef = 1
+      } else if (key == "requires")
+         reqs = reqs " " $(i)
+      else if (key == "default")
+         deflt = deflt " " $(i)
+      else
+         break # Format error, handled below
+
+   setting[$2] = reqs
+   # NOTE: this overwrites a previous value silently
+   if (isdef && deflt == "")
+      deflt = " " # as a flag to force output
+   defaults[$2] = deflt
+   next
+}
+
+# The order of the dependency lines (option, chunk, setting) is irrelevant
+# - the 'enables', 'requires' and 'if' settings will be used to determine
+# the correct order in the output and the final values in pnglibconf.h are
+# not order dependent.  'requires' and 'if' entries take precedence over
+# 'enables' from other options; if an option requires another option it
+# won't be set regardless of any options that enable it unless the other
+# option is also enabled.
+#
+# Similarly 'enables' trumps a NO_ definition in CFLAGS or pngusr.h
+#
+# For simplicity cycles in the definitions are regarded as errors,
+# even if they are not ambiguous.
+# A given NAME can be specified in as many 'option' lines as required, the
+# definitions are additive.
+
+# For backwards compatibility equivalent macros may be listed thus:
+#
+# = [NO_]NAME MACRO
+#   Makes -DMACRO equivalent to -DPNG_NO_NAME or -DPNG_NAME_SUPPORTED
+#   as appropriate.
+#
+# The definition is injected into the C compiler input when encountered
+# in the second pass (so all these definitions appear *after* the @
+# lines!)
+#
+# 'NAME' is as above, but 'MACRO' is the full text of the equivalent
+# old, deprecated, macro.
+
+$1 == "=" && NF == 3{
+   print "#ifdef PNG_" $3 >out
+   if ($2 ~ /^NO_/)
+      print "#   define PNG_" $2 >out
+   else
+      print "#   define PNG_" $2 "_SUPPORTED" >out
+   print "#endif" >out
+   next
+}
+
+# Lines may be injected into the C compiler input by preceding them
+# with an "@" character.  The line is copied with just the leading
+# @ removed.
+
+$1 ~ /^@/{
+   # sub(/^[ 	]*@/, "")
+   $1 = substr($1, 2)
+   print >out
+   next
+}
+
+# Check for unrecognized lines, because of the preprocessing chunk
+# format errors will be detected on the first pass independent of
+# any other format errors.
+{
+   print "options.awk: bad line (" NR "):", $0
+   err = 1 # prevent END{} running
+   exit 1
+}
+
+# For checking purposes names that start with "ok_" or "fail_" are
+# not output to pnglibconf.h and must be either enabled or disabled
+# respectively for the build to succeed.  This allows interdependencies
+# between options of the form "at least one of" or "at most one of"
+# to be checked.  For example:
+#
+# option FLOATING_POINT enables ok_math
+# option FIXED_POINT enables ok_math
+#   This ensures that at least one of FLOATING_POINT and FIXED_POINT
+#   must be set for the build to succeed.
+#
+# option fail_math requires FLOATING_POINT FIXED_POINT
+#   This means the build will fail if *both* FLOATING_POINT and
+#   FIXED_POINT are set (this is an example; in fact both are allowed.)
+#
+# If all these options were given the build would require exactly one
+# of the names to be enabled.
+
+END{
+   # END{} gets run on an exit (a traditional awk feature)
+   if (err) exit 1
+
+   if (pre) {
+      # Record the final value of the variables
+      print "deb =", deb >out
+      if (everything != "") {
+         print "everything =", everything >out
+      }
+      print "logunsupported =", logunsupported >out
+      exit 0
+   }
+
+   # Do the options first (allowing options to set settings).  The dependency
+   # tree is thus:
+   #
+   #   name     >     name
+   #   name requires  name
+   #   name if        name
+   #   name enabledby name
+   #
+   # First build a list 'tree' by option of all the things on which
+   # it depends.
+   print "" >out
+   print "/* OPTIONS */" >out
+   print comment, "options", cend >out
+   for (opt in enabledby) tree[opt] = 1  # may not be explicit options
+   for (opt in option) if (opt != "") {
+      o = option[opt]
+      # option should always be one of the following values
+      if (o != "on" && o != "off" && o != "disabled" && o != "enabled") {
+         print "internal option error (" o ")"
+         exit 1
+      }
+      tree[opt] = ""   # so unlisted options marked
+   }
+   for (opt in tree) if (opt != "") {
+      if (tree[opt] == 1) {
+         tree[opt] = ""
+         if (option[opt] != "") {
+            print "internal error (1)"
+            exit 1
+         }
+         # Macros only listed in 'enables' remain off unless
+         # one of the enabling macros is on.
+         option[opt] = "disabled"
+      }
+
+      split("", list) # clear 'list'
+      # Now add every requires, iffs or enabledby entry to 'list'
+      # so that we can add a unique list of requirements to tree[i]
+      split(requires[opt] iffs[opt] enabledby[opt], r)
+      for (i in r) list[r[i]] = 1
+      for (i in list) tree[opt] = tree[opt] " " i
+   }
+
+   # print the tree for extreme debugging
+   if (deb > 2) for (i in tree) if (i != "") print i, "depends-on" tree[i]
+
+   # Ok, now check all options marked explicitly 'on' or 'off':
+   #
+   # If an option[opt] is 'on' then turn on all requires[opt]
+   # If an option[opt] is 'off' then turn off all enabledby[opt]
+   #
+   # Error out if we have to turn 'on' to an 'off' option or vice versa.
+   npending = 0
+   for (opt in option) if (opt != "") {
+      if (option[opt] == "on" || option[opt] == "off") {
+         pending[++npending] = opt
+      }
+   }
+
+   err = 0 # set on error
+   while (npending > 0) {
+      opt = pending[npending--]
+      if (option[opt] == "on") {
+         nreqs = split(requires[opt], r)
+         for (j=1; j<=nreqs; ++j) {
+            if (option[r[j]] == "off") {
+               print "option", opt, "turned on, but requirement", r[j], "is turned off"
+               err = 1
+            } else if (option[r[j]] != "on") {
+               option[r[j]] = "on"
+               pending[++npending] = r[j]
+            }
+         }
+      } else {
+         if (option[opt] != "off") {
+            print "internal error (2)"
+            exit 1
+         }
+         nreqs = split(enabledby[opt], r)
+         for (j=1; j<=nreqs; ++j) {
+            if (option[r[j]] == "on") {
+               print "option", opt, "turned off, but enabled by", r[j], "which is turned on"
+               err = 1
+            } else if (option[r[j]] != "off") {
+               option[r[j]] = "off"
+               pending[++npending] = r[j]
+            }
+         }
+      }
+   }
+   if (err) exit 1
+
+   # Sort options:
+   print "PNG_DFN_START_SORT 2" >out
+
+   # option[i] is now the complete list of all the tokens we may
+   # need to output, go through it as above, depth first.
+   finished = 0
+   while (!finished) {
+      finished = 1
+      movement = 0 # done nothing
+      for (i in option) if (!done[i]) {
+         nreqs = split(tree[i], r)
+         if (nreqs > 0) {
+            for (j=1; j<=nreqs; ++j) if (!done[r[j]]) {
+               break
+            }
+            if (j<=nreqs) {
+               finished = 0
+               continue  # next option
+            }
+         }
+
+         # All the requirements have been processed, output
+         # this option.  An option is _SUPPORTED if:
+         #
+         # all 'requires' are _SUPPORTED AND
+         # at least one of the 'if' options are _SUPPORTED AND
+         # EITHER:
+         #   The name is _SUPPORTED (on the command line)
+         # OR:
+         #   an 'enabledby' is _SUPPORTED
+         # OR:
+         #   NO_name is not defined AND
+         #   the option is not disabled; an option is disabled if:
+         #    option == off
+         #    option == disabled && everything != on
+         #    option == "" && everything == off
+         if (deb) print "option", i
+         print "" >out
+         print "/* option:", i, option[i] >out
+         print " *   requires:  " requires[i] >out
+         print " *   if:        " iffs[i] >out
+         print " *   enabled-by:" enabledby[i] >out
+         print " *   sets:      " sets[i], "*/" >out
+         print "#undef PNG_on" >out
+         print "#define PNG_on 1" >out
+
+         # requires
+         nreqs = split(requires[i], r)
+         for (j=1; j<=nreqs; ++j) {
+            print "#ifndef PNG_" r[j] "_SUPPORTED" >out
+            print "#   undef PNG_on /*!" r[j] "*/" >out
+            # This error appears in the final output if something
+            # was switched 'on' but the processing above to force
+            # the requires did not work
+            if (option[i] == "on") {
+               print error, i, "requires", r[j] end >out
+            }
+            print "#endif" >out
+         }
+
+         # if
+         have_ifs = 0
+         nreqs = split(iffs[i], r)
+         print "#undef PNG_no_if" >out
+         if (nreqs > 0) {
+            have_ifs = 1
+            print "/* if" iffs[i], "*/" >out
+            print "#define PNG_no_if 1" >out
+            for (j=1; j<=nreqs; ++j) {
+               print "#ifdef PNG_" r[j] "_SUPPORTED" >out
+               print "#   undef PNG_no_if /*" r[j] "*/" >out
+               print "#endif" >out
+            }
+            print "#ifdef PNG_no_if /*missing if*/" >out
+            print "#   undef PNG_on" >out
+            # There is no checking above for this, because we
+            # don't know which 'if' to choose, so whine about
+            # it here:
+            if (option[i] == "on") {
+               print error, i, "needs one of:", iffs[i] end >out
+            }
+            print "#endif" >out
+         }
+
+         print "#ifdef PNG_on /*requires, if*/" >out
+         # enables
+         print "#   undef PNG_not_enabled" >out
+         print "#   define PNG_not_enabled 1" >out
+         print "   /* enabled by" enabledby[i], "*/" >out
+         nreqs = split(enabledby[i], r)
+         for (j=1; j<=nreqs; ++j) {
+            print "#ifdef PNG_" r[j] "_SUPPORTED" >out
+            print "#   undef PNG_not_enabled /*" r[j] "*/" >out
+            # Oops, probably not intended (should be factored
+            # out by the checks above).
+            if (option[i] == "off") {
+               print error, i, "enabled by:", r[j] end >out
+            }
+            print "#endif" >out
+         }
+
+         print "#   ifndef PNG_" i "_SUPPORTED /*!command line*/" >out
+         print "#    ifdef PNG_not_enabled /*!enabled*/" >out
+         # 'have_ifs' here means that everything = "off" still allows an 'if' on
+         # an otherwise enabled option to turn it on; otherwise the 'if'
+         # handling is effectively disabled by 'everything = off'
+         if ((option[i] == "off") ||
+             (option[i] == "disabled" && everything != "on") ||
+             (option[i] == "enabled" && everything == "off" && !have_ifs)) {
+            print "#      undef PNG_on /*default off*/" >out
+         } else {
+            print "#      ifdef PNG_NO_" i >out
+            print "#       undef PNG_on /*turned off*/" >out
+            print "#      endif" >out
+            print "#      ifdef PNG_NO_" i "_SUPPORTED" >out
+            print "#       undef PNG_on /*turned off*/" >out
+            print "#      endif" >out
+         }
+         print "#    endif /*!enabled*/" >out
+         print "#    ifdef PNG_on" >out
+         # The _SUPPORTED macro must be defined so that dependent
+         # options output later work.
+         print "#      define PNG_" i "_SUPPORTED" >out
+         print "#    endif" >out
+         print "#   endif /*!command line*/" >out
+         # If PNG_on is still set the option should be defined in
+         # pnglibconf.h
+         print "#   ifdef PNG_on" >out
+         if (i ~ /^fail_/) {
+            print error, i, "is on:",
+                  "enabled by:" iffs[i] enabledby[i] ", requires" requires[i] end >out
+         } else if (i !~ /^ok_/) {
+            print def i sup >out
+            # Supported option, set required settings
+            nreqs = split(sets[i], r)
+            for (j=1; j<=nreqs; ++j) {
+               print "#    ifdef PNG_set_" r[j] >out
+               # Some other option has already set a value:
+               print error, i, "sets", r[j] ": duplicate setting" end >out
+               print error, "   previous value: " end "PNG_set_" r[j] >out
+               print "#    else" >out
+               # Else set the default: note that this won't accept arbitrary
+               # values, the setval string must be acceptable to all the C
+               # compilers we use.  That means it must be VERY simple; a number,
+               # a name or a string.
+               print "#     define PNG_set_" r[j], setval[i " " r[j]] >out
+               print "#    endif" >out
+            }
+         }
+         print "#   endif /* definition */" >out
+         print "#endif /*requires, if*/" >out
+         if (logunsupported || i ~ /^ok_/) {
+            print "#ifndef  PNG_on" >out
+            if (logunsupported) {
+               print und i une >out
+            }
+            if (i ~ /^ok_/) {
+               print error, i, "not enabled: ",
+                     "requires:" requires[i] ", enabled by:" iffs[i] enabledby[i] end >out
+            }
+            print "#endif" >out
+         }
+
+         done[i] = 1
+         ++movement
+      }
+
+      if (!finished && !movement) {
+         print "option: loop or missing option in dependency tree, cannot process:"
+         for (i in option) if (!done[i]) {
+            print "  option", i, "depends on" tree[i], "needs:"
+            nreqs = split(tree[i], r)
+            if (nreqs > 0) for (j=1; j<=nreqs; ++j) if (!done[r[j]]) {
+               print "   " r[j]
+            }
+         }
+         exit 1
+      }
+   }
+   print "PNG_DFN_END_SORT" >out
+   print comment, "end of options", cend >out
+
+   # Do the 'setting' values second, the algorithm the standard
+   # tree walk (O(1)) done in an O(2) while/for loop; iterations
+   # settings x depth, outputting the deepest required macros
+   # first.
+   print "" >out
+   print "/* SETTINGS */" >out
+   print comment, "settings", cend >out
+   # Sort (in dfn.awk) on field 2, the setting name
+   print "PNG_DFN_START_SORT 2" >out
+   finished = 0
+   while (!finished) {
+      finished = 1
+      movement = 0 # done nothing
+      for (i in setting) if (!doneset[i]) {
+         nreqs = split(setting[i], r)
+         if (nreqs > 0) {
+            # By default assume the requires values are options, but if there
+            # is no option with that name check for a setting
+            for (j=1; j<=nreqs; ++j) if (option[r[j]] == "" && !doneset[r[j]]) {
+               break
+            }
+            if (j<=nreqs) {
+               finished = 0
+               continue # try a different setting
+            }
+         }
+
+         # All the requirements have been processed, output
+         # this setting.
+         if (deb) print "setting", i
+         deflt = defaults[i]
+         # Remove any spurious trailing spaces
+         sub(/ *$/,"",deflt)
+         # A leading @ means leave it unquoted so the preprocessor
+         # can substitute the build time value
+         if (deflt ~ /^ @/)
+            deflt = " " subs substr(deflt, 3) sube
+         print "" >out
+         print "/* setting: ", i >out
+         print " *   requires:" setting[i] >out
+         print " *   default: ", defaults[i] deflt, "*/" >out
+         for (j=1; j<=nreqs; ++j) {
+            if (option[r[j]] != "")
+               print "#ifndef PNG_" r[j] "_SUPPORTED" >out
+            else
+               print "#ifndef PNG_" r[j] >out
+            print error, i, "requires", r[j] end >out
+            print "# endif" >out
+         }
+         # The precedence is:
+         #
+         #  1) External definition; trumps:
+         #  2) Option 'sets' value; trumps:
+         #  3) Setting 'default'
+         #
+         print "#ifdef PNG_" i >out
+         # PNG_<i> is defined, so substitute the value:
+         print def i, subs "PNG_" i sube end >out
+         print "#else /* use default */" >out
+         print "# ifdef PNG_set_" i >out
+         # Value from an option 'sets' argument
+         print def i, subs "PNG_set_" i sube end >out
+         # This is so that subsequent tests on the setting work:
+         print "#  define PNG_" i, "1" >out
+         if (defaults[i] != "") {
+            print "# else /*default*/" >out
+            print def i deflt end >out
+            print "#  define PNG_" i, "1" >out
+         }
+         print "# endif /* defaults */" >out
+         print "#endif /* setting", i, "*/" >out
+
+         doneset[i] = 1
+         ++movement
+      }
+
+      if (!finished && !movement) {
+         print "setting: loop or missing setting in 'requires', cannot process:"
+         for (i in setting) if (!doneset[i]) {
+            print "  setting", i, "requires" setting[i]
+         }
+         exit 1
+      }
+   }
+   print "PNG_DFN_END_SORT" >out
+   print comment, "end of settings", cend >out
+
+   # Regular end - everything looks ok
+   if (protect != "") {
+      print start "#endif", "/*", protect, "*/" end >out
+   }
+}
Index: /trunk/src/libs/libpng-1.6.45/scripts/pnglibconf.dfa
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/pnglibconf.dfa	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/pnglibconf.dfa	(revision 107811)
@@ -0,0 +1,1024 @@
+# scripts/pnglibconf.dfa - library build configuration control
+#
+@/*- pnglibconf.dfn intermediate file
+@ *  generated from scripts/pnglibconf.dfa
+@ */
+#
+com pnglibconf.h - library build configuration
+com
+version
+com
+com Copyright (c) 2018-2024 Cosmin Truta
+com Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+com
+com This code is released under the libpng license.
+com For conditions of distribution and use, see the disclaimer
+com and license in png.h
+com
+
+file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H
+
+# This file is preprocessed by scripts/options.awk and the
+# C compiler to generate 'pnglibconf.h' - a list of all the
+# configuration options.  The file lists the various options
+# that can *only* be specified during the libpng build;
+# pnglibconf.h freezes the definitions selected for the specific
+# build.
+#
+# The syntax is detailed in scripts/options.awk; this is a summary
+# only:
+#
+# setting <name> [requires ...] [default]
+#    #define PNG_<name> <value>  /* value comes from current setting */
+# option <name> [requires ...] [if ...] [enables ...] [disabled]
+#    #define PNG_<name>_SUPPORTED if the requirements are met and
+#    enable the other options listed
+# chunk <name> [requires ...] [enables ...] [disabled]
+#    Enable chunk processing for the given ancillary chunk; any
+#    'requires something' expands to READ_something for read and
+#    WRITE_something for write, but the enables list members are
+#    used as given (e.g. enables GAMMA just expands to that on the
+#    correspond READ_name and WRITE_name lines.)
+#
+# "," may be used to separate options on an 'option' line and is ignored; it
+# doesn't change the meaning of the line.  (NOT setting, where "," becomes
+# part of the setting!)  A comma at the end of an option line causes a
+# continuation (the next line is included in the option too.)
+#
+# Note that the 'on' and 'off' keywords, while valid on both option
+# and chunk, should not be used in this file because they force the
+# relevant options on or off.
+
+#----------------------------------------------------------------------
+
+# The following setting, option and chunk values can all be changed
+# while building libpng:
+#
+# setting: change 'setting' lines to fine tune library performance;
+#   changes to the settings don't affect the libpng API functionally
+#
+# option: change 'option' lines to remove or add capabilities from
+#   or to the library; options change the library API
+#
+# chunk: change 'chunk' lines to remove capabilities to process
+#   optional ('ancillary') chunks.  This does not prevent PNG
+#   decoding but does change the libpng API because some chunks
+#   will be ignored.
+#
+# There are three ways of disabling features, in no particular order:
+#
+# 1) Create 'pngusr.h', enter the required private build information
+# detailed below and #define PNG_NO_<option> for each option you
+# don't want in that file.  You can also turn on options using
+# PNG_<option>_SUPPORTED.  When you have finished, rerun configure
+# and rebuild pnglibconf.h file with -DPNG_USER_CONFIG:
+#
+#  make clean
+#  CPPFLAGS='-DPNG_USER_CONFIG' ./configure
+#  make pnglibconf.h
+#
+# pngusr.h is only used during the creation of pnglibconf.h, but it
+# is safer to ensure that -DPNG_USER_CONFIG is specified throughout
+# the build by changing the CPPFLAGS passed to the initial ./configure
+#
+# 2) Add definitions of the settings you want to change to
+# CPPFLAGS; for example:
+#
+#   -DPNG_DEFAULT_READ_MACROS=0
+#
+# (This would change the default to *not* use read macros.)  Be
+# very careful to change only settings that don't alter the API
+# because this approach bypasses the private build checking.  You
+# can also change settings from pngpriv.h (read pngpriv.h) safely
+# without API changes.  Do that in the same way.
+#
+# 3) Write a new '.dfa' file (say 'pngusr.dfa') and in this file
+# provide override values for setting entries and turn option or
+# chunk values explicitly 'on' or 'off':
+#
+#    setting FOO default VALUE
+#    option BAR [on|off]
+#
+# Then add this file to the options.awk command line (the *first*
+# one) after this file.  The make macro DFA_XTRA is provided to make
+# this easier (set it like CPPFLAGS prior to running ./configure).
+# Look at the builds below contrib/pngminim for some extreme examples
+# of how this can be used.
+#
+# Don't edit this file unless you are contributing a patch to
+# libpng and need new or modified options/settings.
+#----------------------------------------------------------------------
+
+# The following causes commented out #undef lines to be written to
+# pnglibconf.h; this can be stopped by logunsupported=0 in a later
+# file or on the command line (after pnglibconf.dfa)
+
+logunsupported = 1
+
+# The following allows the output from configure to modify the contents of
+# pnglibconf.h
+
+@#ifdef HAVE_CONFIG_H
+@#  include "config.h"
+@#endif
+
+# PNG_USER_CONFIG has to be defined on the compiler command line
+# to cause pngusr.h to be read while constructing pnglibconf.h
+#
+# If you create a private DLL you need to define the following
+# macros in the file 'pngusr.h' and set -DPNG_USER_CONFIG for
+# compilation (i.e. in CPPFLAGS.)
+# #define PNG_USER_PRIVATEBUILD \
+#     <Describes by whom and why this version of the DLL was built>
+#  e.g. #define PNG_USER_PRIVATEBUILD "Build by MyCompany for xyz reasons."
+# #define PNG_USER_DLLFNAME_POSTFIX <two-letter postfix that serve to
+#        distinguish your DLL from those of the official release. These
+#        correspond to the trailing letters that come after the version
+#        number and must match your private DLL name>
+#  e.g. // private DLL "libpng13gx.dll"
+#       #define PNG_USER_DLLFNAME_POSTFIX "gx"
+#
+# The following macros are also at your disposal if you want to complete the
+# DLL VERSIONINFO structure.
+# - PNG_USER_VERSIONINFO_COMMENTS
+# - PNG_USER_VERSIONINFO_COMPANYNAME
+# - PNG_USER_VERSIONINFO_LEGALTRADEMARKS
+
+# It is necessary to include configures definitions here so that AC_DEFINE
+# in configure.ac works in a comprehensible way
+@#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+@#  include "config.h"
+@#endif
+
+@#ifdef PNG_USER_CONFIG
+@#  include "pngusr.h"
+@#endif
+
+# This is a special fixup for the Watcom C compiler on Windows, which has
+# multiple procedure call standards.  Unless PNG_API_RULE is set explicitly
+# (i.e. if it is not defined at this point) it will be forced to '2' here when
+# using Watcom.  This indicates to the other header files that Watcom behaviour
+# is required where appropriate.
+
+@#ifdef __WATCOMC__
+@#  ifndef PNG_API_RULE
+@#     define PNG_API_RULE 2 /* Use Watcom calling conventions */
+@#  endif
+@#endif
+
+# IN DEVELOPMENT
+# These are currently experimental features; define them if you want (NOTE:
+# experimental options must be disabled before they are defined in this file!)
+
+# NONE
+
+# Note that PNG_USER_CONFIG only has an effect when building
+# pnglibconf.h
+
+setting USER_CONFIG
+setting USER_PRIVATEBUILD
+setting USER_DLLFNAME_POSTFIX
+setting USER_VERSIONINFO_COMMENTS
+setting USER_VERSIONINFO_COMPANYNAME
+setting USER_VERSIONINFO_LEGALTRADEMARKS
+
+# Record the 'API rule' used to select calling conventions on
+# those systems that support such things (see all the comments in
+# pngconf.h)
+# Changing this setting has a fundamental affect on the PNG ABI,
+# do not release shared libraries with this changed.
+
+setting API_RULE default 0
+
+# This allows a prefix to be added to the front of every API function name (and
+# therefore every symbol) by redefining all the function names with the prefix
+# at the end of pnglibconf.h.  It also turns on similar internal symbol renaming
+# by causing a similar build-time only file, pngprefix.h, to be generated.
+
+setting PREFIX
+
+# Implementation specific control of the optimizations, enabled by those
+# hardware or software options that need it (typically when run-time choices
+# must be made by the user)
+option SET_OPTION disabled
+
+# These options are specific to the ARM NEON hardware optimizations.  At present
+# these optimizations depend on GCC specific pre-processing of an assembler (.S)
+# file, so they probably won't work with other compilers.
+#
+# ARM_NEON_OPT:
+#   unset: check at compile time
+#          (__ARM_NEON__ must be predefined by the compiler, as a result of
+#          passing "-mfpu=neon" to the compiler options)
+#   0: disable (even if the CPU has a NEON FPU)
+#   1: check at run time (via ARM_NEON_{API,CHECK})
+#   2: switch on unconditionally
+#      (inadvisable - instead, pass "-mfpu=neon" to the compiler)
+#   NOTE:
+#     When building libpng, avoid using any setting other than '0';
+#     '1' is set automatically when either 'API' or 'CHECK' are configured in;
+#     '2' should not be necessary, as "-mfpu=neon" will achieve the same effect
+#     as well as applying the NEON optimizations to the rest of libpng.
+#   NOTE:
+#     Any setting other than '0' requires ALIGNED_MEMORY.
+#
+# ARM_NEON_API:
+#   (PNG_ARM_NEON == 1)
+#   Allow the optimization to be switched on with png_set_option.
+#
+# ARM_NEON_CHECK:
+#   (PNG_ARM_NEON == 1)
+#   Compile a run-time check to see if Neon extensions are supported.
+#   This is poorly supported and deprecated - use the png_set_option API.
+#
+setting ARM_NEON_OPT
+option ARM_NEON_API disabled requires ALIGNED_MEMORY enables SET_OPTION,
+   sets ARM_NEON_OPT 1
+option ARM_NEON_CHECK disabled requires ALIGNED_MEMORY,
+   sets ARM_NEON_OPT 1
+
+# These options are specific to the PowerPC VSX hardware optimizations.
+#
+# POWERPC_VSX_OPT:
+#   unset: check at compile time
+#          (__PPC64__,__ALTIVEC__,__VSX__ must be predefined by the compiler,
+#          as a result of passing "-mvsx -maltivec" to the compiler options)
+#   0: disable (even if the CPU supports VSX)
+#   1: check at run time (via POWERPC_VSX_{API,CHECK})
+#   2: switch on unconditionally
+#      (inadvisable - instead, pass "-mvsx -maltivec" to the compiler)
+#   NOTE:
+#     When building libpng, avoid using any setting other than '0';
+#     '1' is set automatically when either 'API' or 'CHECK' are configured in;
+#     '2' should not be necessary, as "-mvsx -maltivec" will achieve the same
+#     effect as well as applying the VSX optimizations to the rest of libpng.
+#
+# POWERPC_VSX_API:
+#   (PNG_POWERPC_VSX == 1)
+#   Allow the optimization to be switched on with png_set_option.
+#
+# POWERPC_VSX_CHECK:
+#   (PNG_POWERPC_VSX == 1)
+#   Compile a run-time check to see if VSX extensions are supported.
+#   This is not supported on all systems. See contrib/powerpc-vsx/README.
+#
+setting POWERPC_VSX_OPT
+option POWERPC_VSX_API disabled enables SET_OPTION,
+  sets POWERPC_VSX_OPT 1
+option POWERPC_VSX_CHECK disabled,
+  sets POWERPC_VSX_OPT 1
+
+# These options are specific to the MIPS MSA hardware optimizations.
+#
+# MIPS_MSA_OPT:
+#   unset: check at compile time
+#          (__mips_msa must be predefined by the compiler, as a result of
+#          passing "-mmsa -mfp64" to the compiler options)
+#   0: disable (even if the CPU supports MSA)
+#   1: check at run time (via MIPS_MSA_{API,CHECK})
+#   2: switch on unconditionally
+#      (inadvisable - instead, pass "-mmsa -mfp64" to the compiler)
+#   NOTE:
+#     When building libpng, avoid using any setting other than '0';
+#     '1' is set automatically when either 'API' or 'CHECK' are configured in;
+#     '2' should not be necessary, as "-mmsa -mfp64" will achieve the same
+#     effect as well as applying the MSA optimizations to the rest of libpng.
+#   NOTE:
+#     Any setting other than '0' requires ALIGNED_MEMORY.
+#
+# MIPS_MSA_API:
+#   (PNG_MIPS_MSA == 1)
+#   Allow the optimization to be switched on with png_set_option.
+#
+# MIPS_MSA_CHECK:
+#   (PNG_MIPS_MSA == 1)
+#   Compile a run-time check to see if MSA extensions are supported.
+#
+setting MIPS_MSA_OPT
+option MIPS_MSA_API disabled requires ALIGNED_MEMORY enables SET_OPTION,
+  sets MIPS_MSA_OPT 1
+option MIPS_MSA_CHECK disabled requires ALIGNED_MEMORY,
+  sets MIPS_MSA_OPT 1
+
+# These options are specific to the MIPS MMI hardware optimizations.
+#
+# MIPS_MMI_OPT:
+#   unset: check at compile time
+#          (__mips_loongson_mmi must be defined by the compiler, as a result of
+#          passing "-mloongson-mmi -march=loongson3a" to the compiler options)
+#   0: disable (even if the CPU supports MMI)
+#   1: check at run time (via MIPS_MMI_{API,CHECK})
+#   2: switch on unconditionally
+#      (inadvisable - instead, pass "-mloongson-mmi -march=loongson3a" to the
+#      compiler)
+#   NOTE:
+#     When building libpng, avoid using any setting other than '0';
+#     '1' is set automatically when either 'API' or 'CHECK' are configured in;
+#     '2' should not be necessary, as "-mloongson-mmi -march=loongson3a" will
+#     achieve the same effect as well as applying the MMI optimizations to the
+#     rest of libpng.
+#
+# MIPS_MMI_API:
+#   (PNG_MIPS_MMI == 1)
+#   Allow the optimization to be switched on with png_set_option.
+#
+# MIPS_MMI_CHECK:
+#   (PNG_MIPS_MMI == 1)
+#   Compile a run-time check to see if MMI extensions are supported.
+#
+setting MIPS_MMI_OPT
+option MIPS_MMI_API disabled requires ALIGNED_MEMORY enables SET_OPTION,
+  sets MIPS_MMI_OPT 1
+option MIPS_MMI_CHECK disabled requires ALIGNED_MEMORY,
+  sets MIPS_MMI_OPT 1
+
+
+# These settings configure the default compression level (0-9) and 'strategy';
+# strategy is as defined by the implementors of zlib. It describes the input
+# data and modifies the zlib parameters in an attempt to optimize the balance
+# between search and huffman encoding in the zlib algorithms.  The defaults are
+# the zlib.h defaults - the apparently recursive definition does not arise
+# because the name of the setting is prefixed by PNG_
+#
+# The TEXT values are the defaults when writing compressed text (all forms)
+
+# Include the zlib header so that the defaults below are known
+@#  include <zlib.h>
+
+# The '@' here means to substitute the value when pnglibconf.h is built
+setting Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
+# TODO: why aren't these Z_RLE; zlib.h says that Z_RLE, specifically, is
+# appropriate for PNG images, maybe it doesn't exist in all versions?
+setting Z_DEFAULT_STRATEGY default @Z_FILTERED
+setting Z_DEFAULT_NOFILTER_STRATEGY default @Z_DEFAULT_STRATEGY
+setting ZLIB_VERNUM default @ZLIB_VERNUM
+
+# Linkage of:
+#
+#  API:      libpng API functions
+#  CALLBACK: internal non-file-local callbacks
+#  FUNCTION: internal non-file-local functions
+#  DATA:     internal non-file-local (const) data
+setting LINKAGE_API default extern
+setting LINKAGE_CALLBACK default extern
+setting LINKAGE_FUNCTION default extern
+setting LINKAGE_DATA default extern
+
+setting TEXT_Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
+setting TEXT_Z_DEFAULT_STRATEGY default @Z_DEFAULT_STRATEGY
+
+# Default to using the read macros
+
+setting DEFAULT_READ_MACROS default 1
+
+# The alternative is to call functions to read PNG values, if
+# the functions are turned *off* the read macros must always
+# be enabled, so turning this off will actually force the
+# USE_READ_MACROS option on (see pngconf.h)
+
+option READ_INT_FUNCTIONS requires READ
+
+# The same for write  but these can only be switched off if no writing
+# is required at all - hence the use of a 'disabled', not a 'requires'.
+# If these are needed, they are enabled in the 'WRITE options' section
+# below.
+
+option WRITE_INT_FUNCTIONS disabled
+
+# Error controls
+#
+# WARNINGS: normally on, if off no warnings are generated
+# ERROR_TEXT: normally on, if off errors happen but there is no message
+# ERROR_NUMBERS: unimplemented feature, therefore disabled
+# BENIGN_ERRORS: support for just issuing warnings for recoverable errors
+#
+# BENIGN_READ_ERRORS:
+#     By default recoverable errors on read should just generate warnings,
+#     generally safe but PNG files that don't conform to the specification will
+#     be accepted if a meaningful result can be produced.
+#
+# BENIGN_WRITE_ERRORS:
+#     By default recoverable errors on write should just generate warnings,
+#     not generally safe because this allows the application to write invalid
+#     PNG files.  Applications should enable this themselves; it's useful
+#     because it means that a failure to write an ancillary chunk can often be
+#     ignored.
+
+option WARNINGS
+option ERROR_TEXT
+option ERROR_NUMBERS disabled
+
+option BENIGN_ERRORS
+option BENIGN_WRITE_ERRORS requires BENIGN_ERRORS disabled
+option BENIGN_READ_ERRORS requires BENIGN_ERRORS
+
+# Adler32 checksum
+#
+# This option allows the check of the Adler32 checksum performed by zlib to
+# be turned off for IDAT chunks (only).  Unless this option is enabled and
+# turned on (not the default even if enabled) a failed Adler32 at the end of the
+# stream will result in a decompression (inflate) failure on read even though
+# the entire image might have been read successfully.
+#
+# This option relies on an undocumented function 'inflateValidate' which is
+# present in only some versions of zlib.  If the function is not present in the
+# zlib used with libpng code which uses -lpng is likely to fail to link or to
+# launch in the case of a DLL.
+#
+# Therefore this option is currently disabled by default; it has to be turned on
+# in pngusr.dfa and then the application program has to explicitly turn the
+# functionality on by calling png_set_option.
+#
+# Furthermore the option is explicitly turned off here if the zlib version
+# number is below that required - libpng wouldn't compile in that case if the
+# option were turned on.
+option DISABLE_ADLER32_CHECK requires READ enables SET_OPTION disabled
+
+# ZLIB_VERNUM must be used here, not PNG_ZLIB_VERNUM, because
+# scripts/options.awk ends up putting this test adhead of the setting of
+# PNG_ZLIB_VERNUM (apparently above, but not because of the two-pass processing)
+@#if ZLIB_VERNUM < 0x1290
+@#   define PNG_NO_DISABLE_ADLER32_CHECK
+@#endif
+
+# Generic options - affect both read and write.
+
+option MNG_FEATURES
+
+# Arithmetic options, the first is the big switch that chooses between internal
+# floating and fixed point arithmetic implementations - it does not affect any
+# APIs.  The second two (the _POINT settings) switch off individual APIs.
+#
+# Prior to libpng 1.6.8 one of the API (_POINT) variants had to be selected.  At
+# 1.6.8 this restriction has been removed; the simplified API can be used
+# without enabling any of the low level fixed/floating APIs.
+
+option FLOATING_ARITHMETIC
+option FLOATING_POINT
+option FIXED_POINT
+
+# This protects us against compilers that run on a windowing system
+# and thus don't have or would rather us not use the stdio types:
+# stdin, stdout, and stderr.  The only one currently used is stderr
+# in png_error() and png_warning().  #defining PNG_NO_CONSOLE_IO will
+# prevent these from being compiled and used. #defining PNG_NO_STDIO
+# will also prevent these, plus will prevent the entire set of stdio
+# macros and functions (FILE *, printf, etc.) from being compiled and used,
+# unless (PNG_DEBUG > 0) has been #defined.
+
+option STDIO
+option CONSOLE_IO requires STDIO
+
+# Note: prior to 1.5.0 this option could not be disabled if STDIO
+# was enabled.  Prior to 1.5.3 this option required STDIO
+
+option TIME_RFC1123
+
+# PNG_SETJMP_NOT_SUPPORTED is an old equivalent for NO_SETJMP
+
+option SETJMP
+= NO_SETJMP SETJMP_NOT_SUPPORTED
+
+# If this is disabled it is not possible for apps to get the
+# values from the 'info' structure, this effectively removes
+# quite a lot of the READ API.
+
+option EASY_ACCESS
+
+# Added at libpng-1.2.0
+
+option USER_MEM
+
+# Added at libpng-1.4.0
+
+option IO_STATE
+
+# Libpng limits: limit the size of images and data on read.
+#
+# If this option is disabled all the limit checking code will be disabled:
+
+option USER_LIMITS requires READ
+
+# The default settings given below for the limits mean that libpng will
+# limit the size of images or the size of data in ancillary chunks to less
+# than the specification or implementation limits. Settings have the
+# following interpretations:
+#
+# USER_WIDTH_MAX: maximum width of an image that will be read
+# USER_HEIGHT_MAX: maximum height
+# USER_CHUNK_MALLOC_MAX: maximum in-memory (decompressed) size of a single chunk
+# USER_CHUNK_CACHE_MAX: maximum number of chunks to be cached
+#
+# Only chunks that are variable in number are counted towards the
+
+# Use 0x7fffffff for unlimited
+setting USER_WIDTH_MAX default        1000000
+setting USER_HEIGHT_MAX default       1000000
+
+# Use 0 for unlimited
+setting USER_CHUNK_CACHE_MAX default     1000
+setting USER_CHUNK_MALLOC_MAX default 8000000
+
+# If this option is enabled APIs to set the above limits at run time are added;
+# without this the hardwired (compile time) limits will be used.
+option SET_USER_LIMITS requires USER_LIMITS
+
+# All of the following options relate to code capabilities for
+# processing image data before creating a PNG or after reading one.
+# You can remove these capabilities safely and still be PNG
+# conformant, however the library that results is still non-standard.
+# See the comments above about how to change options and settings.
+
+# READ options
+#
+# WARNING: in libpng 1.5 maintained configuration compatibility with earlier
+# versions.  In some cases turning off an option turned off other options, in
+# others it was ineffective unless dependent options were also turned off.
+# Libpng 1.6 changes this: in general if you turn off an option that affects
+# APIs it stays off and simply disables APIs that depend on it.
+#
+# As a result if you simply port the libpng 1.5 configuration to libpng 1.6 you
+# will probably see build failures due to missing APIs.  Fixing these failures
+# requires some, perhaps considerable, knowledge of what your libpng using
+# applications are doing, fortunately there is no great reason for you to move
+# to libpng 1.6; the new interfaces in 1.6 will take several years to become
+# popular.
+
+option READ enables READ_INTERLACING SET_OPTION
+
+# Disabling READ_16BIT does not disable reading 16-bit PNG files, but it
+# forces them to be chopped down to 8-bit, and disables any 16-bit
+# processing after that has happened.  You need to be sure to enable
+# READ_SCALE_16_TO_8 or READ_STRIP_16_TO_8 when you disable READ_16BIT for
+# this to work properly.  You should disable the other option if you need to
+# ensure a particular conversion (otherwise the app can chose.)
+
+option READ_16BIT requires READ enables 16BIT
+
+option READ_QUANTIZE requires READ
+
+option READ_TRANSFORMS requires READ
+= NO_READ_TRANSFORMS READ_TRANSFORMS_NOT_SUPPORTED
+
+# Read gamma handling.  Gamma processing is a core part of libpng and many of
+# the capabilities are dependent on libpng performing gamma correction.
+#
+# In libpng 1.6 disabling gamma processing (setting PNG_NO_READ_GAMMA)
+# consistently disables those parts of the API that depend on it.  Prior to
+# 1.6.0 this was not true; the results were unpredictable and varied between
+# releases.
+#
+# If you disable gamma processing and your program no longer compiles you need
+# to ask whether you really need the APIs that are missing.  If you do then you
+# almost certainly need the gamma processing.
+#
+# If you handle gamma issues outside libpng then you do not need the libpng
+# gamma processing; and it is an enormous waste of space.  You just need to
+# remove the use of libpng APIs that depend on it.
+option READ_GAMMA requires READ_TRANSFORMS, READ_gAMA, READ_sRGB
+
+option READ_ALPHA_MODE requires READ_TRANSFORMS, READ_GAMMA
+option READ_BACKGROUND requires READ_TRANSFORMS, READ_STRIP_ALPHA, READ_GAMMA
+option READ_BGR requires READ_TRANSFORMS
+option READ_EXPAND_16 requires READ_TRANSFORMS, READ_16BIT, READ_EXPAND
+option READ_EXPAND requires READ_TRANSFORMS
+option READ_FILLER requires READ_TRANSFORMS
+option READ_GRAY_TO_RGB requires READ_TRANSFORMS
+option READ_INVERT_ALPHA requires READ_TRANSFORMS
+option READ_INVERT requires READ_TRANSFORMS
+option READ_PACK requires READ_TRANSFORMS
+option READ_PACKSWAP requires READ_TRANSFORMS
+option READ_RGB_TO_GRAY requires READ_TRANSFORMS, READ_GAMMA enables COLORSPACE
+option READ_SCALE_16_TO_8 requires READ_TRANSFORMS
+option READ_SHIFT requires READ_TRANSFORMS
+option READ_STRIP_16_TO_8 requires READ_TRANSFORMS
+option READ_STRIP_ALPHA requires READ_TRANSFORMS
+option READ_SWAP_ALPHA requires READ_TRANSFORMS
+option READ_SWAP requires READ_TRANSFORMS, READ_16BIT
+option READ_USER_TRANSFORM requires READ_TRANSFORMS
+
+option PROGRESSIVE_READ requires READ
+option SEQUENTIAL_READ requires READ
+
+# You can define PNG_NO_PROGRESSIVE_READ if you don't do progressive reading.
+# This is not talking about interlacing capability!  You'll still have
+# interlacing unless you turn off the following which is required
+# for PNG-compliant decoders.  (In other words, do not do this - in
+# fact it can't be disabled from the command line!)
+#option READ_INTERLACING requires READ
+
+option READ_COMPOSITE_NODIV requires READ
+= NO_READ_COMPOSITE_NODIV NO_READ_COMPOSITED_NODIV
+
+# Inch conversions
+
+option INCH_CONVERSIONS
+= INCH_CONVERSIONS INCH_CONVERSIONS
+
+# API to build a grayscale palette
+# NOTE: this is not used internally by libpng at present.
+
+option BUILD_GRAYSCALE_PALETTE
+
+# WRITE options
+
+option WRITE enables WRITE_INT_FUNCTIONS
+
+# Disabling WRITE_16BIT prevents 16-bit PNG files from being
+# generated.
+option WRITE_16BIT requires WRITE enables 16BIT
+
+option WRITE_TRANSFORMS requires WRITE
+= NO_WRITE_TRANSFORMS WRITE_TRANSFORMS_NOT_SUPPORTED
+
+option WRITE_SHIFT requires WRITE_TRANSFORMS
+option WRITE_PACK requires WRITE_TRANSFORMS
+option WRITE_BGR requires WRITE_TRANSFORMS
+option WRITE_SWAP requires WRITE_TRANSFORMS, WRITE_16BIT
+option WRITE_PACKSWAP requires WRITE_TRANSFORMS
+option WRITE_INVERT requires WRITE_TRANSFORMS
+option WRITE_FILLER requires WRITE_TRANSFORMS
+option WRITE_SWAP_ALPHA requires WRITE_TRANSFORMS
+option WRITE_INVERT_ALPHA requires WRITE_TRANSFORMS
+option WRITE_USER_TRANSFORM requires WRITE_TRANSFORMS
+
+# This is not required for PNG-compliant encoders, but can cause
+# trouble if left undefined
+
+option WRITE_INTERLACING requires WRITE
+
+# Deprecated, will be removed.
+option WRITE_WEIGHTED_FILTER requires WRITE
+
+option WRITE_FLUSH requires WRITE
+
+# Note: these can be turned off explicitly if not required by the
+# apps implementing the user transforms
+option USER_TRANSFORM_PTR if READ_USER_TRANSFORM, WRITE_USER_TRANSFORM
+option USER_TRANSFORM_INFO if READ_USER_TRANSFORM, WRITE_USER_TRANSFORM
+
+# This enables API to set compression parameters for compressing
+# non-IDAT chunks (zTXt, iTXt, iCCP, and unknown chunks).  This feature
+# was added at libpng-1.5.3.
+option WRITE_CUSTOMIZE_ZTXT_COMPRESSION requires WRITE
+option WRITE_CUSTOMIZE_COMPRESSION requires WRITE
+
+# Any chunks you are not interested in, you can undef here.  The
+# ones that allocate memory may be especially important (hIST,
+# tEXt, zTXt, tRNS, pCAL).  Others will just save time and make png_info
+# a bit smaller.
+
+# The size of the png_text structure changed in libpng-1.0.6 when
+# iTXt support was added.  iTXt support was turned off by default through
+# libpng-1.2.x, to support old apps that malloc the png_text structure
+# instead of calling png_set_text() and letting libpng malloc it.  It
+# was turned on by default in libpng-1.4.0.
+
+option READ_ANCILLARY_CHUNKS requires READ
+# PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED is deprecated.
+= NO_READ_ANCILLARY_CHUNKS READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+option WRITE_ANCILLARY_CHUNKS requires WRITE
+# PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED is deprecated.
+= NO_WRITE_ANCILLARY_CHUNKS WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+# These options disable *all* the text chunks if turned off
+
+option TEXT disabled
+option READ_TEXT requires READ_ANCILLARY_CHUNKS enables TEXT
+option WRITE_TEXT requires WRITE_ANCILLARY_CHUNKS enables TEXT
+
+# Moved to pnglibconf.h at libpng-1.5.0
+# Feature support: in 1.4 this was in pngconf.h, but the following
+# features have no affect on the libpng API.  Add library
+# only features to the end of this list.  Add features that
+# affect the API above.  (Note: the list of chunks follows
+# the library-only settings.)
+#
+# BUILD TIME ONLY OPTIONS
+#   These options do not affect the API but rather alter how the
+#   API is implemented, they get recorded in pnglibconf.h, but
+#   can't be changed by the application.
+
+# Colorspace support (enabled as required); just the support for colorant
+# information.  Gamma support, likewise, is just support for the gamma
+# information, READ_GAMMA is required for gamma transformations (so it
+# is possible to read PNG gamma without enabling all the libpng transform
+# code - do this for applications that do their own gamma processing)
+#
+# As of 1.6.0 COLORSPACE is only useful if the application processes the
+# information; this is because the library does not do any colorspace
+# processing, it just validates the data in the PNG file.
+
+option GAMMA disabled
+option COLORSPACE enables GAMMA disabled
+
+# When an ICC profile is read, or png_set, it will be checked for a match
+# against known sRGB profiles if the sRGB handling is enabled.  The
+# PNG_sRGB_PROFILE_CHECKS setting controls how much work is done during the
+# check:
+#
+# -1: Don't do any sRGB profile checking.
+#
+#  0: Just validate the profile MD5 signature if present, otherwise use
+#     the checks in option 1.
+#
+#  1: Additionally check the length, intent and adler32 checksum of the
+#     actual data.   If enabled this will reject known profiles that have
+#     had the rendering intent in the header changed as well as other edits
+#     done without updating the checksum.  See the discussion below.
+#
+#  2: Additionally checksum all the data using the ethernet CRC32 algorithm.
+#     This makes it more difficult to fake profiles and makes it less likely
+#     to get a false positive on profiles with no signature, but is probably
+#     just a waste of time since all currently approved ICC sRGB profiles have
+#     a secure MD5 signature.
+#
+# The rendering intent.  An ICC profile stores an intended rendering intent,
+# but does not include the value in the signature.  The intent is documented
+# as the intent that should be used when combining two profiles.  The sRGB
+# profile is intended, however, to be used with any of the four defined intents.
+# For this reason the sRGB chunk includes an 'intent' to be used when displaying
+# the image (intent is really a property of the image not the profile.)
+#
+# Unfortunately the iCCP chunk does not.  It may therefore be that some
+# applications modify the intent in profiles (including sRGB profiles) to work
+# round this problem.  Selecting an option other than option '0' will cause such
+# modified profiles to be rejected.
+#
+# Security.  The use of Adler32 and CRC32 checksums does not help significantly
+# with any security issues.  It is relatively easy to produce arbitrary profiles
+# with the required checksums on current computer systems.  Nevertheless
+# security does not seem to be an issue because the only consequence of a false
+# positive is a false assertion that the profile is an sRGB profile.  This might
+# be used to hide data from libpng using applications, but it doesn't seem
+# possible to damage them.
+
+setting sRGB_PROFILE_CHECKS default 2
+
+# Artificially align memory - the code typically aligns to 8 byte
+# boundaries if this is switched on, it's a small waste of space
+# but can help (in theory) on some architectures.  Only affects
+# internal structures.  Added at libpng 1.4.0
+
+option ALIGNED_MEMORY
+
+# Buggy compilers (e.g., gcc 2.7.2.2) need PNG_NO_POINTER_INDEXING
+# See png[wr]util.c, normally this should always be *on*
+
+option POINTER_INDEXING
+
+# Other defines for things like memory and the like can go here.
+
+# BUILD TIME SETTINGS
+# Like build time options these do not affect the API, but they
+# may be useful to applications because they record details of
+# how the API will behave particularly with regard to overall
+# accuracy.
+
+# This controls how fine the quantizing gets.  As this allocates
+# a largish chunk of memory (32K), those who are not as concerned
+# with quantizing quality can decrease some or all of these.
+
+setting QUANTIZE_RED_BITS default 5
+setting QUANTIZE_GREEN_BITS default 5
+setting QUANTIZE_BLUE_BITS default 5
+
+# This controls how fine the gamma correction becomes when you
+# are only interested in 8 bits anyway.  Increasing this value
+# results in more memory being used, and more pow() functions
+# being called to fill in the gamma tables.  Don't set this value
+# less than 8, and even that may not work (I haven't tested it).
+
+setting MAX_GAMMA_8 default 11
+
+# This controls how much a difference in gamma we can tolerate before
+# we actually start doing gamma conversion, it's a fixed point value,
+# so the default below is 0.05, meaning libpng ignores corrections in
+# the range 0.95 to 1.05
+
+setting GAMMA_THRESHOLD_FIXED default 5000
+
+# Precision to use when converting a floating point value to a PNG
+# extension format string in an sCAL chunk (only relevant if the
+# floating point API is enabled)
+
+setting sCAL_PRECISION default 5
+
+# This is the size of the compression buffer, and thus the size of
+# an IDAT chunk.  Make this whatever size you feel is best for your
+# machine.  One of these will be allocated per png_struct.  When this
+# is full, it writes the data to the disk, and does some other
+# calculations.  Making this an extremely small size may slow
+# the library down, but you may want to experiment to determine
+# where it becomes significant, if you are concerned with memory
+# usage.  Note that zlib allocates at least 32Kb also.  For readers,
+# this describes the size of the buffer available to read the data in.
+# Unless this gets smaller than the size of a row (compressed),
+# it should not make much difference how big this is.
+
+setting ZBUF_SIZE default 8192
+
+# This is the size of the decompression buffer used when counting or checking
+# the decompressed size of an LZ stream from a compressed ancillary chunk; the
+# decompressed data is never used so a different size may be optimal.  This size
+# was determined using contrib/libtests/timepng.c with compressed zTXt data
+# around 11MByte in size.  Slight speed improvements (up to about 14% in
+# timepng) can be achieved by very large increases (to 32kbyte) on regular data,
+# but highly compressible data shows only around 2% improvement.   The size is
+# chosen to minimize the effects of DoS attacks based on using very large
+# amounts of highly compressible data.
+
+setting INFLATE_BUF_SIZE default 1024
+
+# This is the maximum amount of IDAT data that the sequential reader will
+# process at one time.  The setting does not affect the size of IDAT chunks
+# read, just the amount read at once.  Neither does it affect the progressive
+# reader, which processes just the amount of data the application gives it.
+# The sequential reader is currently unable to process more than one IDAT at
+# once - it has to read and process each one in turn.  There is no point setting
+# this to a value larger than the IDAT chunks typically encountered (it would
+# just waste memory) but there may be some point in reducing it below the value
+# of ZBUF_SIZE (the size of IDAT chunks written by libpng.)
+
+setting IDAT_READ_SIZE default PNG_ZBUF_SIZE
+
+# Ancillary chunks
+chunk bKGD
+chunk cHRM enables COLORSPACE
+chunk eXIf
+chunk gAMA enables GAMMA
+chunk hIST
+chunk iCCP enables COLORSPACE, GAMMA
+chunk iTXt enables TEXT
+chunk oFFs
+chunk pCAL
+chunk pHYs
+chunk sBIT
+chunk sCAL
+chunk sPLT
+chunk sRGB enables COLORSPACE, GAMMA, SET_OPTION
+chunk tEXt requires TEXT
+chunk tIME
+chunk tRNS
+chunk zTXt enables TEXT
+
+# This only affects support of the optional PLTE chunk in RGB and RGBA
+# images.  Notice that READ_ANCILLARY_CHUNKS therefore disables part
+# of the regular chunk reading too.
+
+option READ_OPT_PLTE requires READ_ANCILLARY_CHUNKS
+
+# Unknown chunk handling
+#
+# 'UNKNOWN_CHUNKS' is a global option to disable all unknown chunk handling on
+# read or write; everything else below requires it (directly or indirectly).
+option UNKNOWN_CHUNKS
+
+# There are three main options to control the ability to read and write unknown
+# chunks.  If either read option is turned on then unknown chunks will be read,
+# otherwise they are skipped.  If the write option is turned on unknown chunks
+# set by png_set_unknown_chunks will be written otherwise it is an error to call
+# that API on a write struct.
+option WRITE_UNKNOWN_CHUNKS requires WRITE requires UNKNOWN_CHUNKS
+option WRITE_UNKNOWN_CHUNKS enables STORE_UNKNOWN_CHUNKS
+
+# The first way to read user chunks is to have libpng save them for a later call
+# to png_get_unknown_chunks, the application must call
+# png_set_keep_unknown_chunks to cause this to actually happen (see png.h)
+option SAVE_UNKNOWN_CHUNKS requires READ requires SET_UNKNOWN_CHUNKS
+option SAVE_UNKNOWN_CHUNKS enables READ_UNKNOWN_CHUNKS, STORE_UNKNOWN_CHUNKS
+
+# The second approach is to use an application provided callback to process the
+# chunks, the callback can either handle the chunk entirely itself or request
+# that libpng store the chunk for later retrieval via png_get_unknown_chunks.
+#
+# NOTE: If STORE_UNKNOWN_CHUNKS is not enabled (which is the default if
+# both SAVE_UNKNOWN_CHUNKS and WRITE_UNKNOWN_CHUNKS are disabled) then a
+# 0 result from the callback will be ignored because no support for saving
+# unknown chunks has been compiled in.  The normal symptom is that your app
+# fails to compile because png_get_unknown_chunks is no longer defined in png.h.
+# If you encounter this issue simply enable STORE_UNKNOWN_CHUNKS in your build.
+#
+# Note that there is no 'WRITE_USER_CHUNKS' so the USER_CHUNKS option is always
+# the same as READ_USER_CHUNKS at present
+option READ_USER_CHUNKS requires READ, UNKNOWN_CHUNKS
+option READ_USER_CHUNKS enables READ_UNKNOWN_CHUNKS, USER_CHUNKS
+
+# Two further options are provided to allow detailed control of the handling.
+# The first enables png_set_keep_unknown_chunks; this allows the default to be
+# changed from discarding unknown chunks and allows per-chunk control.  This is
+# required to use the SAVE_UNKNOWN_CHUNKS option.  If enabled this option also
+# applies to write (see png.h), otherwise the write API simply writes all the
+# chunks it is given.
+#
+# The second option extends the unknown handling to allow known chunks to be
+# handled as though they were unknown.  This option doesn't change any APIs, it
+# merely turns on the code to check known as well as unknown chunks.
+#
+# This option no longer affects the write code.  It can be safely disabled and
+# will prevent applications stopping libpng reading known chunks.
+option SET_UNKNOWN_CHUNKS requires UNKNOWN_CHUNKS
+option HANDLE_AS_UNKNOWN requires SET_UNKNOWN_CHUNKS
+
+# The following options are derived from the above and should not be turned on
+# explicitly.
+option READ_UNKNOWN_CHUNKS requires UNKNOWN_CHUNKS disabled
+option STORE_UNKNOWN_CHUNKS requires UNKNOWN_CHUNKS disabled
+
+option CONVERT_tIME requires WRITE_ANCILLARY_CHUNKS
+# The "tm" structure is not supported on WindowsCE
+
+@#ifdef _WIN32_WCE
+@#   define PNG_NO_CONVERT_tIME
+@#endif
+
+option WRITE_FILTER requires WRITE
+
+option SAVE_INT_32 disabled
+# png_save_int_32 is required internally for writing the ancillary chunks oFFs
+# and pCAL and for both reading and writing iCCP (for the generation/checking of
+# the corresponding cHRM/gAMA chunks) if full ICC is supported.
+
+# added at libpng-1.5.4
+
+option WRITE_OPTIMIZE_CMF requires WRITE
+
+option READ_COMPRESSED_TEXT disabled
+option READ_iCCP enables READ_COMPRESSED_TEXT
+option READ_iTXt enables READ_COMPRESSED_TEXT
+option READ_zTXt enables READ_COMPRESSED_TEXT
+
+option WRITE_oFFs enables SAVE_INT_32
+option WRITE_pCAL enables SAVE_INT_32
+option WRITE_cHRM enables SAVE_INT_32
+
+option WRITE_COMPRESSED_TEXT disabled
+option WRITE_iCCP enables WRITE_COMPRESSED_TEXT
+option WRITE_iTXt enables WRITE_COMPRESSED_TEXT
+option WRITE_zTXt enables WRITE_COMPRESSED_TEXT
+
+# Turn this off to disable png_read_png() and png_write_png() and
+# leave the row_pointers member out of the info structure.
+
+option INFO_IMAGE
+
+# added at libpng-1.5.10
+# Turn this off to disable warning about invalid palette index and
+# leave the num_palette_max member out of the png structure.
+
+option CHECK_FOR_INVALID_INDEX enables READ_CHECK_FOR_INVALID_INDEX
+option CHECK_FOR_INVALID_INDEX enables WRITE_CHECK_FOR_INVALID_INDEX
+option READ_CHECK_FOR_INVALID_INDEX requires READ, CHECK_FOR_INVALID_INDEX
+option WRITE_CHECK_FOR_INVALID_INDEX requires WRITE, CHECK_FOR_INVALID_INDEX
+
+# added at libpng-1.5.15
+option GET_PALETTE_MAX enables READ_GET_PALETTE_MAX WRITE_GET_PALETTE_MAX
+option READ_GET_PALETTE_MAX requires READ_CHECK_FOR_INVALID_INDEX disabled
+option WRITE_GET_PALETTE_MAX requires WRITE_CHECK_FOR_INVALID_INDEX disabled
+
+# Simplified API options (added at libpng-1.6.0)
+#  In libpng 1.6.8 the handling of these options was changed to used 'requires'
+#  throughout, so that disabling some of the low level support always disables
+#  the base simplified read/write API.  This much simplifies the handling and
+#  makes 'everything = off' work in a more intuitive way.  It eliminates a
+#  previously reported feature that APIs previously enabled by the simplified
+#  API couldn't be turned off without explicitly turning off the simplified
+#  APIs.
+#
+# Read:
+option SIMPLIFIED_READ,
+   requires SEQUENTIAL_READ, READ_TRANSFORMS, SETJMP, BENIGN_ERRORS,
+      READ_EXPAND, READ_16BIT, READ_EXPAND_16, READ_SCALE_16_TO_8,
+      READ_RGB_TO_GRAY, READ_ALPHA_MODE, READ_BACKGROUND, READ_STRIP_ALPHA,
+      READ_FILLER, READ_SWAP, READ_PACK, READ_GRAY_TO_RGB, READ_GAMMA,
+      READ_tRNS, READ_bKGD, READ_gAMA, READ_cHRM, READ_sRGB, READ_sBIT
+
+# AFIRST and BGR read options:
+#  Prior to libpng 1.6.8 these were disabled but switched on if the low level
+#  libpng routines that do the swaps were enabled.  This worked but was
+#  confusing.  In libpng 1.6.8 the options were changed to simple 'requires'
+#  and are enabled by default.  This should work the same way in practice.
+option SIMPLIFIED_READ_AFIRST enables FORMAT_AFIRST,
+   requires SIMPLIFIED_READ READ_SWAP_ALPHA
+
+option SIMPLIFIED_READ_BGR enables FORMAT_BGR,
+   requires SIMPLIFIED_READ READ_BGR
+
+# Write:
+option SIMPLIFIED_WRITE,
+   requires WRITE, SETJMP, WRITE_SWAP, WRITE_PACK,
+      WRITE_tRNS, WRITE_gAMA, WRITE_sRGB, WRITE_cHRM
+
+# 1.6.22: allow simplified write without stdio support:
+option SIMPLIFIED_WRITE_STDIO requires SIMPLIFIED_WRITE STDIO
+
+option SIMPLIFIED_WRITE_AFIRST enables FORMAT_AFIRST,
+   requires SIMPLIFIED_WRITE WRITE_SWAP_ALPHA
+
+option SIMPLIFIED_WRITE_BGR enables FORMAT_BGR,
+   requires SIMPLIFIED_WRITE WRITE_BGR
+
+# Formats:
+option FORMAT_AFIRST disabled
+option FORMAT_BGR disabled
Index: /trunk/src/libs/libpng-1.6.45/scripts/pnglibconf.h.prebuilt
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/pnglibconf.h.prebuilt	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/pnglibconf.h.prebuilt	(revision 107811)
@@ -0,0 +1,224 @@
+/* pnglibconf.h - library build configuration */
+
+/* libpng version 1.6.43 */
+
+/* Copyright (c) 2018-2024 Cosmin Truta */
+/* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson */
+
+/* This code is released under the libpng license. */
+/* For conditions of distribution and use, see the disclaimer */
+/* and license in png.h */
+
+/* pnglibconf.h */
+/* Machine generated file: DO NOT EDIT */
+/* Derived from: scripts/pnglibconf.dfa */
+#ifndef PNGLCONF_H
+#define PNGLCONF_H
+/* options */
+#define PNG_16BIT_SUPPORTED
+#define PNG_ALIGNED_MEMORY_SUPPORTED
+/*#undef PNG_ARM_NEON_API_SUPPORTED*/
+/*#undef PNG_ARM_NEON_CHECK_SUPPORTED*/
+#define PNG_BENIGN_ERRORS_SUPPORTED
+#define PNG_BENIGN_READ_ERRORS_SUPPORTED
+/*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/
+#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+#define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_COLORSPACE_SUPPORTED
+#define PNG_CONSOLE_IO_SUPPORTED
+#define PNG_CONVERT_tIME_SUPPORTED
+/*#undef PNG_DISABLE_ADLER32_CHECK_SUPPORTED*/
+#define PNG_EASY_ACCESS_SUPPORTED
+/*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
+#define PNG_ERROR_TEXT_SUPPORTED
+#define PNG_FIXED_POINT_SUPPORTED
+#define PNG_FLOATING_ARITHMETIC_SUPPORTED
+#define PNG_FLOATING_POINT_SUPPORTED
+#define PNG_FORMAT_AFIRST_SUPPORTED
+#define PNG_FORMAT_BGR_SUPPORTED
+#define PNG_GAMMA_SUPPORTED
+#define PNG_GET_PALETTE_MAX_SUPPORTED
+#define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#define PNG_INCH_CONVERSIONS_SUPPORTED
+#define PNG_INFO_IMAGE_SUPPORTED
+#define PNG_IO_STATE_SUPPORTED
+/*#undef PNG_MIPS_MMI_API_SUPPORTED*/
+/*#undef PNG_MIPS_MMI_CHECK_SUPPORTED*/
+/*#undef PNG_MIPS_MSA_API_SUPPORTED*/
+/*#undef PNG_MIPS_MSA_CHECK_SUPPORTED*/
+#define PNG_MNG_FEATURES_SUPPORTED
+#define PNG_POINTER_INDEXING_SUPPORTED
+/*#undef PNG_POWERPC_VSX_API_SUPPORTED*/
+/*#undef PNG_POWERPC_VSX_CHECK_SUPPORTED*/
+#define PNG_PROGRESSIVE_READ_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+#define PNG_READ_ALPHA_MODE_SUPPORTED
+#define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
+#define PNG_READ_BACKGROUND_SUPPORTED
+#define PNG_READ_BGR_SUPPORTED
+#define PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_READ_COMPOSITE_NODIV_SUPPORTED
+#define PNG_READ_COMPRESSED_TEXT_SUPPORTED
+#define PNG_READ_EXPAND_16_SUPPORTED
+#define PNG_READ_EXPAND_SUPPORTED
+#define PNG_READ_FILLER_SUPPORTED
+#define PNG_READ_GAMMA_SUPPORTED
+#define PNG_READ_GET_PALETTE_MAX_SUPPORTED
+#define PNG_READ_GRAY_TO_RGB_SUPPORTED
+#define PNG_READ_INTERLACING_SUPPORTED
+#define PNG_READ_INT_FUNCTIONS_SUPPORTED
+#define PNG_READ_INVERT_ALPHA_SUPPORTED
+#define PNG_READ_INVERT_SUPPORTED
+#define PNG_READ_OPT_PLTE_SUPPORTED
+#define PNG_READ_PACKSWAP_SUPPORTED
+#define PNG_READ_PACK_SUPPORTED
+#define PNG_READ_QUANTIZE_SUPPORTED
+#define PNG_READ_RGB_TO_GRAY_SUPPORTED
+#define PNG_READ_SCALE_16_TO_8_SUPPORTED
+#define PNG_READ_SHIFT_SUPPORTED
+#define PNG_READ_STRIP_16_TO_8_SUPPORTED
+#define PNG_READ_STRIP_ALPHA_SUPPORTED
+#define PNG_READ_SUPPORTED
+#define PNG_READ_SWAP_ALPHA_SUPPORTED
+#define PNG_READ_SWAP_SUPPORTED
+#define PNG_READ_TEXT_SUPPORTED
+#define PNG_READ_TRANSFORMS_SUPPORTED
+#define PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_READ_USER_CHUNKS_SUPPORTED
+#define PNG_READ_USER_TRANSFORM_SUPPORTED
+#define PNG_READ_bKGD_SUPPORTED
+#define PNG_READ_cHRM_SUPPORTED
+#define PNG_READ_eXIf_SUPPORTED
+#define PNG_READ_gAMA_SUPPORTED
+#define PNG_READ_hIST_SUPPORTED
+#define PNG_READ_iCCP_SUPPORTED
+#define PNG_READ_iTXt_SUPPORTED
+#define PNG_READ_oFFs_SUPPORTED
+#define PNG_READ_pCAL_SUPPORTED
+#define PNG_READ_pHYs_SUPPORTED
+#define PNG_READ_sBIT_SUPPORTED
+#define PNG_READ_sCAL_SUPPORTED
+#define PNG_READ_sPLT_SUPPORTED
+#define PNG_READ_sRGB_SUPPORTED
+#define PNG_READ_tEXt_SUPPORTED
+#define PNG_READ_tIME_SUPPORTED
+#define PNG_READ_tRNS_SUPPORTED
+#define PNG_READ_zTXt_SUPPORTED
+#define PNG_SAVE_INT_32_SUPPORTED
+#define PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_SEQUENTIAL_READ_SUPPORTED
+#define PNG_SETJMP_SUPPORTED
+#define PNG_SET_OPTION_SUPPORTED
+#define PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_SET_USER_LIMITS_SUPPORTED
+#define PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
+#define PNG_SIMPLIFIED_READ_BGR_SUPPORTED
+#define PNG_SIMPLIFIED_READ_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_SUPPORTED
+#define PNG_STDIO_SUPPORTED
+#define PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_TEXT_SUPPORTED
+#define PNG_TIME_RFC1123_SUPPORTED
+#define PNG_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_USER_CHUNKS_SUPPORTED
+#define PNG_USER_LIMITS_SUPPORTED
+#define PNG_USER_MEM_SUPPORTED
+#define PNG_USER_TRANSFORM_INFO_SUPPORTED
+#define PNG_USER_TRANSFORM_PTR_SUPPORTED
+#define PNG_WARNINGS_SUPPORTED
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED
+#define PNG_WRITE_BGR_SUPPORTED
+#define PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#define PNG_WRITE_FILLER_SUPPORTED
+#define PNG_WRITE_FILTER_SUPPORTED
+#define PNG_WRITE_FLUSH_SUPPORTED
+#define PNG_WRITE_GET_PALETTE_MAX_SUPPORTED
+#define PNG_WRITE_INTERLACING_SUPPORTED
+#define PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+#define PNG_WRITE_INVERT_ALPHA_SUPPORTED
+#define PNG_WRITE_INVERT_SUPPORTED
+#define PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+#define PNG_WRITE_PACKSWAP_SUPPORTED
+#define PNG_WRITE_PACK_SUPPORTED
+#define PNG_WRITE_SHIFT_SUPPORTED
+#define PNG_WRITE_SUPPORTED
+#define PNG_WRITE_SWAP_ALPHA_SUPPORTED
+#define PNG_WRITE_SWAP_SUPPORTED
+#define PNG_WRITE_TEXT_SUPPORTED
+#define PNG_WRITE_TRANSFORMS_SUPPORTED
+#define PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_WRITE_USER_TRANSFORM_SUPPORTED
+#define PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+#define PNG_WRITE_bKGD_SUPPORTED
+#define PNG_WRITE_cHRM_SUPPORTED
+#define PNG_WRITE_eXIf_SUPPORTED
+#define PNG_WRITE_gAMA_SUPPORTED
+#define PNG_WRITE_hIST_SUPPORTED
+#define PNG_WRITE_iCCP_SUPPORTED
+#define PNG_WRITE_iTXt_SUPPORTED
+#define PNG_WRITE_oFFs_SUPPORTED
+#define PNG_WRITE_pCAL_SUPPORTED
+#define PNG_WRITE_pHYs_SUPPORTED
+#define PNG_WRITE_sBIT_SUPPORTED
+#define PNG_WRITE_sCAL_SUPPORTED
+#define PNG_WRITE_sPLT_SUPPORTED
+#define PNG_WRITE_sRGB_SUPPORTED
+#define PNG_WRITE_tEXt_SUPPORTED
+#define PNG_WRITE_tIME_SUPPORTED
+#define PNG_WRITE_tRNS_SUPPORTED
+#define PNG_WRITE_zTXt_SUPPORTED
+#define PNG_bKGD_SUPPORTED
+#define PNG_cHRM_SUPPORTED
+#define PNG_eXIf_SUPPORTED
+#define PNG_gAMA_SUPPORTED
+#define PNG_hIST_SUPPORTED
+#define PNG_iCCP_SUPPORTED
+#define PNG_iTXt_SUPPORTED
+#define PNG_oFFs_SUPPORTED
+#define PNG_pCAL_SUPPORTED
+#define PNG_pHYs_SUPPORTED
+#define PNG_sBIT_SUPPORTED
+#define PNG_sCAL_SUPPORTED
+#define PNG_sPLT_SUPPORTED
+#define PNG_sRGB_SUPPORTED
+#define PNG_tEXt_SUPPORTED
+#define PNG_tIME_SUPPORTED
+#define PNG_tRNS_SUPPORTED
+#define PNG_zTXt_SUPPORTED
+/* end of options */
+/* settings */
+#define PNG_API_RULE 0
+#define PNG_DEFAULT_READ_MACROS 1
+#define PNG_GAMMA_THRESHOLD_FIXED 5000
+#define PNG_IDAT_READ_SIZE PNG_ZBUF_SIZE
+#define PNG_INFLATE_BUF_SIZE 1024
+#define PNG_LINKAGE_API extern
+#define PNG_LINKAGE_CALLBACK extern
+#define PNG_LINKAGE_DATA extern
+#define PNG_LINKAGE_FUNCTION extern
+#define PNG_MAX_GAMMA_8 11
+#define PNG_QUANTIZE_BLUE_BITS 5
+#define PNG_QUANTIZE_GREEN_BITS 5
+#define PNG_QUANTIZE_RED_BITS 5
+#define PNG_TEXT_Z_DEFAULT_COMPRESSION (-1)
+#define PNG_TEXT_Z_DEFAULT_STRATEGY 0
+#define PNG_USER_CHUNK_CACHE_MAX 1000
+#define PNG_USER_CHUNK_MALLOC_MAX 8000000
+#define PNG_USER_HEIGHT_MAX 1000000
+#define PNG_USER_WIDTH_MAX 1000000
+#define PNG_ZBUF_SIZE 8192
+#define PNG_ZLIB_VERNUM 0 /* unknown */
+#define PNG_Z_DEFAULT_COMPRESSION (-1)
+#define PNG_Z_DEFAULT_NOFILTER_STRATEGY 0
+#define PNG_Z_DEFAULT_STRATEGY 1
+#define PNG_sCAL_PRECISION 5
+#define PNG_sRGB_PROFILE_CHECKS 2
+/* end of settings */
+#endif /* PNGLCONF_H */
Index: /trunk/src/libs/libpng-1.6.45/scripts/pnglibconf.mak
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/pnglibconf.mak	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/pnglibconf.mak	(revision 107811)
@@ -0,0 +1,55 @@
+#!/usr/bin/make -f
+# pnglibconf.mak - standard make lines for pnglibconf.h
+#
+# These lines are copied from Makefile.am, they illustrate
+# how to automate the build of pnglibconf.h from scripts/pnglibconf.dfa
+# given just 'awk', a C preprocessor and standard command line utilities
+
+# Override as appropriate, these definitions can be overridden on
+# the make command line (AWK='nawk' for example).
+AWK = gawk
+AWK = mawk
+AWK = nawk
+AWK = one-true-awk
+AWK = awk      # This fails on SunOS 5.10; use 'nawk'
+CPP = $(CC) -E # If this fails on SunOS 5.10, use '/lib/cpp'
+
+MOVE = mv -f
+DELETE = rm -f
+
+DFA_XTRA = # Put your configuration file here, see scripts/pnglibconf.dfa.  Eg:
+# DFA_XTRA = pngusr.dfa
+
+# CPPFLAGS should contain the options to control the result,
+# but DEFS and CFLAGS are also supported here, override
+# as appropriate
+DFNFLAGS = $(DEFS) $(CPPFLAGS) $(CFLAGS)
+
+# srcdir is a de-facto standard for the location of the source
+srcdir = .
+
+# The standard pnglibconf.h exists as scripts/pnglibconf.h.prebuilt,
+# copy this if the following doesn't work.
+pnglibconf.h: pnglibconf.dfn
+	$(DELETE) $@ pnglibconf.c pnglibconf.out pnglibconf.tmp
+	echo '#include "pnglibconf.dfn"' >pnglibconf.c
+	@echo "## If '$(CC) -E' fails, try /lib/cpp (e.g. CPP='/lib/cpp')" >&2
+	$(CPP) $(DFNFLAGS) pnglibconf.c >pnglibconf.out
+	$(AWK) -f $(srcdir)/scripts/dfn.awk out=pnglibconf.tmp pnglibconf.out >&2
+	$(MOVE) pnglibconf.tmp $@
+
+pnglibconf.dfn: $(srcdir)/scripts/pnglibconf.dfa $(srcdir)/scripts/options.awk $(srcdir)/pngconf.h $(srcdir)/pngusr.dfa $(DFA_XTRA)
+	$(DELETE) $@ pnglibconf.pre pnglibconf.tmp
+	@echo "## Calling $(AWK) from scripts/pnglibconf.mak" >&2
+	@echo "## If 'awk' fails, try a better awk (e.g. AWK='nawk')" >&2
+	$(AWK) -f $(srcdir)/scripts/options.awk out=pnglibconf.pre\
+	    version=search $(srcdir)/pngconf.h $(srcdir)/scripts/pnglibconf.dfa\
+	    $(srcdir)/pngusr.dfa $(DFA_XTRA) >&2
+	$(AWK) -f $(srcdir)/scripts/options.awk out=pnglibconf.tmp pnglibconf.pre >&2
+	$(MOVE) pnglibconf.tmp $@
+
+clean-pnglibconf:
+	$(DELETE) pnglibconf.h pnglibconf.c pnglibconf.out pnglibconf.pre \
+	pnglibconf.dfn
+
+clean: clean-pnglibconf
Index: /trunk/src/libs/libpng-1.6.45/scripts/pngwin.rc
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/pngwin.rc	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/pngwin.rc	(revision 107811)
@@ -0,0 +1,112 @@
+#define PNG_VERSION_INFO_ONLY
+
+#include <windows.h>
+#include "../png.h"
+
+#define _QUOTE(x) # x
+#define QUOTE(x) _QUOTE(x)
+
+#define PNG_LIBPNG_DLLFNAME "LIBPNG"
+
+/* Support deprecated PRIVATEBUILD macro */
+#if defined(PRIVATEBUILD) && !defined(PNG_USER_PRIVATEBUILD)
+#  define PNG_USER_PRIVATEBUILD PRIVATEBUILD
+#endif
+
+#if defined(PNG_USER_DLLFNAME_POSTFIX) && !defined(PNG_USER_PRIVATEBUILD)
+#  error "PNG_USER_PRIVATEBUILD must be defined as a string describing the\
+ custom changes made to the library."
+#endif
+
+/* Prioritize PNG_USER_x over PNG_LIBPNG_x */
+#ifdef PNG_USER_DLLFNAME_POSTFIX
+#  undef PNG_LIBPNG_DLLFNAME_POSTFIX
+#  define PNG_LIBPNG_DLLFNAME_POSTFIX PNG_USER_DLLFNAME_POSTFIX
+#endif
+
+#ifdef PNG_USER_VERSIONINFO_COMMENTS
+#  undef PNG_LIBPNG_VERSIONINFO_COMMENTS
+#  define PNG_LIBPNG_VERSIONINFO_COMMENTS PNG_USER_VERSIONINFO_COMMENTS
+#endif
+
+#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
+#  define VS_DEBUG VS_FF_DEBUG
+#  ifndef PNG_LIBPNG_DLLFNAME_POSTFIX
+#    define PNG_LIBPNG_DLLFNAME_POSTFIX "D"
+#  endif /* PNG_LIBPNG_DLLFNAME_POSTFIX */
+#  ifndef PNG_LIBPNG_VERSIONINFO_COMMENTS
+#    define PNG_LIBPNG_VERSIONINFO_COMMENTS "PNG_DEBUG=" QUOTE(PNG_DEBUG)
+#  endif /* PNG_LIBPNG_VERSIONINFO_COMMENTS */
+#else
+#  define VS_DEBUG 0
+#  ifndef PNG_LIBPNG_DLLFNAME_POSTFIX
+#     define PNG_LIBPNG_DLLFNAME_POSTFIX
+#  endif /* PNG_LIBPNG_DLLFNAME_POSTFIX */
+#endif /* defined(DEBUG)... */
+
+#ifdef PNG_USER_PRIVATEBUILD
+#  define VS_PRIVATEBUILD VS_FF_PRIVATEBUILD
+#else
+#  define VS_PRIVATEBUILD 0
+#endif /* PNG_USER_PRIVATEBUILD */
+
+#ifdef PNG_LIBPNG_SPECIALBUILD
+#  define VS_SPECIALBUILD VS_FF_SPECIALBUILD
+#else
+#  define VS_SPECIALBUILD 0
+#endif /* PNG_LIBPNG_BUILD_SPECIAL */
+
+#if ((PNG_LIBPNG_BUILD_BASE_TYPE & PNG_LIBPNG_RELEASE_STATUS_MASK) !=\
+      PNG_LIBPNG_BUILD_STABLE)
+#  define VS_PRERELEASE VS_FF_PRERELEASE
+#  define VS_PATCHED 0
+#else
+#  define VS_PRERELEASE 0
+#  if (PNG_LIBPNG_BUILD_BASE_TYPE & PNG_LIBPNG_BUILD_PATCHED)
+#    define VS_PATCHED VS_FF_PATCHED
+#  else
+#    define VS_PATCHED 0
+#  endif
+#endif
+
+VS_VERSION_INFO VERSIONINFO
+FILEVERSION PNG_LIBPNG_VER_MAJOR, PNG_LIBPNG_VER_MINOR, PNG_LIBPNG_VER_RELEASE, PNG_LIBPNG_VER_BUILD
+PRODUCTVERSION PNG_LIBPNG_VER_MAJOR, PNG_LIBPNG_VER_MINOR, PNG_LIBPNG_VER_RELEASE, PNG_LIBPNG_VER_BUILD
+FILEFLAGSMASK VS_FFI_FILEFLAGSMASK
+FILEFLAGS VS_DEBUG | VS_PRIVATEBUILD | VS_SPECIALBUILD | VS_PRERELEASE | VS_PATCHED
+FILEOS VOS__WINDOWS32
+FILETYPE VFT_DLL
+FILESUBTYPE VFT2_UNKNOWN
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN BLOCK "040904E4" /* Language type = U.S English(0x0409) and Character Set = Windows, Multilingual(0x04E4) */
+    BEGIN
+#ifdef PNG_LIBPNG_VERSIONINFO_COMMENTS
+      VALUE "Comments", PNG_LIBPNG_VERSIONINFO_COMMENTS "\000"
+#endif /* PNG_LIBPNG_VERSIONINFO_COMMENTS */
+#ifdef PNG_USER_VERSIONINFO_COMPANYNAME
+      VALUE "CompanyName", PNG_USER_VERSIONINFO_COMPANYNAME "\000"
+#endif /* PNG_USER_VERSIONINFO_COMPANYNAME */
+      VALUE "FileDescription", "PNG image compression library\000"
+      VALUE "FileVersion", PNG_LIBPNG_VER_STRING "\000"
+      VALUE "InternalName", PNG_LIBPNG_DLLFNAME QUOTE(PNG_LIBPNG_VER_SHAREDLIB) PNG_LIBPNG_DLLFNAME_POSTFIX " (Windows)\000"
+      VALUE "LegalCopyright", "\251 1998-2024 PNG Reference Library Authors\000"
+#ifdef PNG_USER_VERSIONINFO_LEGALTRADEMARKS
+      VALUE "LegalTrademarks", PNG_USER_VERSIONINFO_LEGALTRADEMARKS "\000"
+#endif /* PNG_USER_VERSIONINFO_LEGALTRADEMARKS */
+      VALUE "OriginalFilename", PNG_LIBPNG_DLLFNAME QUOTE(PNG_LIBPNG_VER_SHAREDLIB) PNG_LIBPNG_DLLFNAME_POSTFIX ".DLL\000"
+#ifdef PNG_USER_PRIVATEBUILD
+      VALUE "PrivateBuild", PNG_USER_PRIVATEBUILD "\000"
+#endif /* PNG_USER_PRIVATEBUILD */
+      VALUE "ProductName", "LibPNG\000"
+      VALUE "ProductVersion", "1\000"
+#ifdef PNG_LIBPNG_SPECIALBUILD
+      VALUE "SpecialBuild", PNG_LIBPNG_SPECIALBUILD "\000"
+#endif /* PNG_LIBPNG_SPECIALBUILD */
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x0409, 0x04E4
+  END
+END
Index: /trunk/src/libs/libpng-1.6.45/scripts/prefix.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/prefix.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/prefix.c	(revision 107811)
@@ -0,0 +1,23 @@
+
+/* prefix.c - generate an unprefixed symbol list
+ *
+ * Copyright (c) 2013-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+        PNG_DFN "@" name "@"
+
+/* The configuration information *before* the additional of symbol renames,
+ * the list is the C name list; no symbol prefix.
+ */
+#include "pnglibconf.out"
+
+PNG_DFN_START_SORT 1
+
+#include "../png.h"
+
+PNG_DFN_END_SORT
Index: /trunk/src/libs/libpng-1.6.45/scripts/smakefile.ppc
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/smakefile.ppc	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/smakefile.ppc	(revision 107811)
@@ -0,0 +1,33 @@
+# Amiga powerUP (TM) Makefile
+# makefile for libpng and SAS C V6.58/7.00 PPC compiler
+# Copyright (C) 1998 by Andreas R. Kleinert
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+CC       = scppc
+CFLAGS   = NOSTKCHK NOSINT OPTIMIZE OPTGO OPTPEEP OPTINLOCAL OPTINL IDIR /zlib \
+           OPTLOOP OPTRDEP=8 OPTDEP=8 OPTCOMP=8
+LIBNAME  = libpng.a
+AR       = ppc-amigaos-ar
+ARFLAGS  = cr
+RANLIB   = ppc-amigaos-ranlib
+LDFLAGS  = -r -o
+LDLIBS   =  ../zlib/libzip.a LIB:scppc.a
+LN       = ppc-amigaos-ld
+RM       = delete quiet
+
+OBJS = png.o pngerror.o pngget.o pngmem.o pngpread.o \
+       pngread.o pngrio.o pngrtran.o pngrutil.o pngset.o \
+       pngtrans.o pngwio.o pngwrite.o pngwtran.o pngwutil.o
+
+all: $(LIBNAME) pngtest
+
+$(LIBNAME): $(OBJS)
+            $(AR) $(ARFLAGS) $@ $(OBJS)
+            $(RANLIB) $@
+
+pngtest: pngtest.o $(LIBNAME)
+        $(LN) $(LDFLAGS) pngtest LIB:c_ppc.o pngtest.o $(LIBNAME) $(LDLIBS) \
+LIB:end.o
Index: /trunk/src/libs/libpng-1.6.45/scripts/sym.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/sym.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/sym.c	(revision 107811)
@@ -0,0 +1,14 @@
+
+/* sym.c - define format of libpng.sym
+ *
+ * Copyright (c) 2011-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+        PNG_DFN "@" SYMBOL_PREFIX "@@" name "@"
+
+#include "../png.h"
Index: /trunk/src/libs/libpng-1.6.45/scripts/symbols.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/symbols.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/symbols.c	(revision 107811)
@@ -0,0 +1,57 @@
+
+/* symbols.c - find all exported symbols
+ *
+ * Copyright (c) 2011-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* NOTE: making 'symbols.chk' checks both that the exported
+ * symbols in the library don't change and (implicitly) that
+ * scripts/pnglibconf.h.prebuilt is as expected.
+ * If scripts/pnglibconf.h.prebuilt is remade using
+ * scripts/pnglibconf.dfa then this checks the .dfa file too.
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+        PNG_DFN "@" name "@ @@" ordinal "@"
+#define PNG_REMOVED(ordinal, type, name, args, attributes)\
+        PNG_DFN "; @" name "@ @@" ordinal "@"
+#define PNG_EXPORT_LAST_ORDINAL(ordinal)\
+        PNG_DFN "; @@" ordinal "@"
+
+/* Read the defaults, but use scripts/pnglibconf.h.prebuilt; the 'standard'
+ * header file.
+ */
+#include "pnglibconf.h.prebuilt"
+#include "../png.h"
+
+/* Some things are turned off by default.  Turn these things
+ * on here (by hand) to get the APIs they expose and validate
+ * that no harm is done.  This list is the set of options
+ * defaulted to 'off' in scripts/pnglibconf.dfa
+ *
+ * Maintenance: if scripts/pnglibconf.dfa options are changed
+ * from, or to, 'disabled' this needs updating!
+ */
+#define PNG_BENIGN_ERRORS_SUPPORTED
+#define PNG_ERROR_NUMBERS_SUPPORTED
+#define PNG_READ_BIG_ENDIAN_SUPPORTED  /* should do nothing! */
+#define PNG_INCH_CONVERSIONS_SUPPORTED
+#define PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+#define PNG_SET_OPTION_SUPPORTED
+
+#undef PNG_H
+#include "../png.h"
+
+/* Finally there are a couple of places where option support
+ * actually changes the APIs revealed using a #if/#else/#endif
+ * test in png.h, test these here.
+ */
+#undef  PNG_FLOATING_POINT_SUPPORTED /* Exposes 'fixed' APIs */
+#undef  PNG_ERROR_TEXT_SUPPORTED     /* Exposes unsupported APIs */
+
+#undef PNG_H
+#include "../png.h"
Index: /trunk/src/libs/libpng-1.6.45/scripts/symbols.def
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/symbols.def	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/symbols.def	(revision 107811)
@@ -0,0 +1,255 @@
+;--------------------------------------------------------------
+; LIBPNG symbol list as a Win32 DEF file
+; Contains all the symbols that can be exported from libpng
+;--------------------------------------------------------------
+LIBRARY
+
+EXPORTS
+ png_access_version_number @1
+ png_set_sig_bytes @2
+ png_sig_cmp @3
+ png_create_read_struct @4
+ png_create_write_struct @5
+ png_get_compression_buffer_size @6
+ png_set_compression_buffer_size @7
+ png_set_longjmp_fn @8
+ png_longjmp @9
+ png_reset_zstream @10
+ png_create_read_struct_2 @11
+ png_create_write_struct_2 @12
+ png_write_sig @13
+ png_write_chunk @14
+ png_write_chunk_start @15
+ png_write_chunk_data @16
+ png_write_chunk_end @17
+ png_create_info_struct @18
+ png_info_init_3 @19
+ png_write_info_before_PLTE @20
+ png_write_info @21
+ png_read_info @22
+ png_convert_to_rfc1123 @23
+ png_convert_from_struct_tm @24
+ png_convert_from_time_t @25
+ png_set_expand @26
+ png_set_expand_gray_1_2_4_to_8 @27
+ png_set_palette_to_rgb @28
+ png_set_tRNS_to_alpha @29
+ png_set_bgr @30
+ png_set_gray_to_rgb @31
+ png_set_rgb_to_gray @32
+ png_set_rgb_to_gray_fixed @33
+ png_get_rgb_to_gray_status @34
+ png_build_grayscale_palette @35
+ png_set_strip_alpha @36
+ png_set_swap_alpha @37
+ png_set_invert_alpha @38
+ png_set_filler @39
+ png_set_add_alpha @40
+ png_set_swap @41
+ png_set_packing @42
+ png_set_packswap @43
+ png_set_shift @44
+ png_set_interlace_handling @45
+ png_set_invert_mono @46
+ png_set_background @47
+ png_set_strip_16 @48
+ png_set_quantize @49
+ png_set_gamma @50
+ png_set_flush @51
+ png_write_flush @52
+ png_start_read_image @53
+ png_read_update_info @54
+ png_read_rows @55
+ png_read_row @56
+ png_read_image @57
+ png_write_row @58
+ png_write_rows @59
+ png_write_image @60
+ png_write_end @61
+ png_read_end @62
+ png_destroy_info_struct @63
+ png_destroy_read_struct @64
+ png_destroy_write_struct @65
+ png_set_crc_action @66
+ png_set_filter @67
+ png_set_filter_heuristics @68
+ png_set_compression_level @69
+ png_set_compression_mem_level @70
+ png_set_compression_strategy @71
+ png_set_compression_window_bits @72
+ png_set_compression_method @73
+ png_init_io @74
+ png_set_error_fn @75
+ png_get_error_ptr @76
+ png_set_write_fn @77
+ png_set_read_fn @78
+ png_get_io_ptr @79
+ png_set_read_status_fn @80
+ png_set_write_status_fn @81
+ png_set_mem_fn @82
+ png_get_mem_ptr @83
+ png_set_read_user_transform_fn @84
+ png_set_write_user_transform_fn @85
+ png_set_user_transform_info @86
+ png_get_user_transform_ptr @87
+ png_set_read_user_chunk_fn @88
+ png_get_user_chunk_ptr @89
+ png_set_progressive_read_fn @90
+ png_get_progressive_ptr @91
+ png_process_data @92
+ png_progressive_combine_row @93
+ png_malloc @94
+ png_calloc @95
+ png_malloc_warn @96
+ png_free @97
+ png_free_data @98
+ png_data_freer @99
+ png_malloc_default @100
+ png_free_default @101
+ png_error @102
+ png_chunk_error @103
+ png_err @104
+ png_warning @105
+ png_chunk_warning @106
+ png_benign_error @107
+ png_chunk_benign_error @108
+ png_set_benign_errors @109
+ png_get_valid @110
+ png_get_rowbytes @111
+ png_get_rows @112
+ png_set_rows @113
+ png_get_channels @114
+ png_get_image_width @115
+ png_get_image_height @116
+ png_get_bit_depth @117
+ png_get_color_type @118
+ png_get_filter_type @119
+ png_get_interlace_type @120
+ png_get_compression_type @121
+ png_get_pixels_per_meter @122
+ png_get_x_pixels_per_meter @123
+ png_get_y_pixels_per_meter @124
+ png_get_pixel_aspect_ratio @125
+ png_get_x_offset_pixels @126
+ png_get_y_offset_pixels @127
+ png_get_x_offset_microns @128
+ png_get_y_offset_microns @129
+ png_get_signature @130
+ png_get_bKGD @131
+ png_set_bKGD @132
+ png_get_cHRM @133
+ png_get_cHRM_fixed @134
+ png_set_cHRM @135
+ png_set_cHRM_fixed @136
+ png_get_gAMA @137
+ png_get_gAMA_fixed @138
+ png_set_gAMA @139
+ png_set_gAMA_fixed @140
+ png_get_hIST @141
+ png_set_hIST @142
+ png_get_IHDR @143
+ png_set_IHDR @144
+ png_get_oFFs @145
+ png_set_oFFs @146
+ png_get_pCAL @147
+ png_set_pCAL @148
+ png_get_pHYs @149
+ png_set_pHYs @150
+ png_get_PLTE @151
+ png_set_PLTE @152
+ png_get_sBIT @153
+ png_set_sBIT @154
+ png_get_sRGB @155
+ png_set_sRGB @156
+ png_set_sRGB_gAMA_and_cHRM @157
+ png_get_iCCP @158
+ png_set_iCCP @159
+ png_get_sPLT @160
+ png_set_sPLT @161
+ png_get_text @162
+ png_set_text @163
+ png_get_tIME @164
+ png_set_tIME @165
+ png_get_tRNS @166
+ png_set_tRNS @167
+ png_get_sCAL @168
+ png_get_sCAL_s @169
+ png_set_sCAL @170
+ png_set_sCAL_s @171
+ png_set_keep_unknown_chunks @172
+ png_handle_as_unknown @173
+ png_set_unknown_chunks @174
+ png_set_unknown_chunk_location @175
+ png_get_unknown_chunks @176
+ png_set_invalid @177
+ png_read_png @178
+ png_write_png @179
+ png_get_copyright @180
+ png_get_header_ver @181
+ png_get_header_version @182
+ png_get_libpng_ver @183
+ png_permit_mng_features @184
+ png_set_strip_error_numbers @185
+ png_set_user_limits @186
+ png_get_user_width_max @187
+ png_get_user_height_max @188
+ png_set_chunk_cache_max @189
+ png_get_chunk_cache_max @190
+ png_set_chunk_malloc_max @191
+ png_get_chunk_malloc_max @192
+ png_get_pixels_per_inch @193
+ png_get_x_pixels_per_inch @194
+ png_get_y_pixels_per_inch @195
+ png_get_x_offset_inches @196
+ png_get_y_offset_inches @197
+ png_get_pHYs_dpi @198
+ png_get_io_state @199
+ png_get_uint_32 @201
+ png_get_uint_16 @202
+ png_get_int_32 @203
+ png_get_uint_31 @204
+ png_save_uint_32 @205
+ png_save_int_32 @206
+ png_save_uint_16 @207
+ png_set_gamma_fixed @208
+ png_set_filter_heuristics_fixed @209
+ png_get_pixel_aspect_ratio_fixed @210
+ png_get_x_offset_inches_fixed @211
+ png_get_y_offset_inches_fixed @212
+ png_set_sCAL_fixed @213
+ png_get_sCAL_fixed @214
+ png_set_background_fixed @215
+ png_get_io_chunk_type @216
+ png_get_current_row_number @217
+ png_get_current_pass_number @218
+ png_process_data_pause @219
+ png_process_data_skip @220
+ png_set_expand_16 @221
+ png_set_text_compression_level @222
+ png_set_text_compression_mem_level @223
+ png_set_text_compression_strategy @224
+ png_set_text_compression_window_bits @225
+ png_set_text_compression_method @226
+ png_set_alpha_mode @227
+ png_set_alpha_mode_fixed @228
+ png_set_scale_16 @229
+ png_get_cHRM_XYZ @230
+ png_get_cHRM_XYZ_fixed @231
+ png_set_cHRM_XYZ @232
+ png_set_cHRM_XYZ_fixed @233
+ png_image_begin_read_from_file @234
+ png_image_begin_read_from_stdio @235
+ png_image_begin_read_from_memory @236
+ png_image_finish_read @237
+ png_image_free @238
+ png_image_write_to_file @239
+ png_image_write_to_stdio @240
+ png_convert_to_rfc1123_buffer @241
+ png_set_check_for_invalid_index @242
+ png_get_palette_max @243
+ png_set_option @244
+ png_image_write_to_memory @245
+ png_get_eXIf @246
+ png_set_eXIf @247
+ png_get_eXIf_1 @248
+ png_set_eXIf_1 @249
Index: /trunk/src/libs/libpng-1.6.45/scripts/vers.c
===================================================================
--- /trunk/src/libs/libpng-1.6.45/scripts/vers.c	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/scripts/vers.c	(revision 107811)
@@ -0,0 +1,18 @@
+
+/* vers.c - define format of libpng.vers
+ *
+ * Copyright (c) 2011-2014 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+        PNG_DFN " @" SYMBOL_PREFIX "@@" name "@;"
+
+PNG_DFN "@" PNGLIB_LIBNAME "@ {global:"
+
+#include "../png.h"
+
+PNG_DFN "local: *; };"
Index: /trunk/src/libs/libpng-1.6.45/test-driver
===================================================================
--- /trunk/src/libs/libpng-1.6.45/test-driver	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/test-driver	(revision 107811)
@@ -0,0 +1,153 @@
+#! /bin/sh
+# test-driver - basic testsuite driver script.
+
+scriptversion=2018-03-07.03; # UTC
+
+# Copyright (C) 2011-2021 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# This file is maintained in Automake, please report
+# bugs to <bug-automake@gnu.org> or send patches to
+# <automake-patches@gnu.org>.
+
+# Make unconditional expansion of undefined variables an error.  This
+# helps a lot in preventing typo-related bugs.
+set -u
+
+usage_error ()
+{
+  echo "$0: $*" >&2
+  print_usage >&2
+  exit 2
+}
+
+print_usage ()
+{
+  cat <<END
+Usage:
+  test-driver --test-name NAME --log-file PATH --trs-file PATH
+              [--expect-failure {yes|no}] [--color-tests {yes|no}]
+              [--enable-hard-errors {yes|no}] [--]
+              TEST-SCRIPT [TEST-SCRIPT-ARGUMENTS]
+
+The '--test-name', '--log-file' and '--trs-file' options are mandatory.
+See the GNU Automake documentation for information.
+END
+}
+
+test_name= # Used for reporting.
+log_file=  # Where to save the output of the test script.
+trs_file=  # Where to save the metadata of the test run.
+expect_failure=no
+color_tests=no
+enable_hard_errors=yes
+while test $# -gt 0; do
+  case $1 in
+  --help) print_usage; exit $?;;
+  --version) echo "test-driver $scriptversion"; exit $?;;
+  --test-name) test_name=$2; shift;;
+  --log-file) log_file=$2; shift;;
+  --trs-file) trs_file=$2; shift;;
+  --color-tests) color_tests=$2; shift;;
+  --expect-failure) expect_failure=$2; shift;;
+  --enable-hard-errors) enable_hard_errors=$2; shift;;
+  --) shift; break;;
+  -*) usage_error "invalid option: '$1'";;
+   *) break;;
+  esac
+  shift
+done
+
+missing_opts=
+test x"$test_name" = x && missing_opts="$missing_opts --test-name"
+test x"$log_file"  = x && missing_opts="$missing_opts --log-file"
+test x"$trs_file"  = x && missing_opts="$missing_opts --trs-file"
+if test x"$missing_opts" != x; then
+  usage_error "the following mandatory options are missing:$missing_opts"
+fi
+
+if test $# -eq 0; then
+  usage_error "missing argument"
+fi
+
+if test $color_tests = yes; then
+  # Keep this in sync with 'lib/am/check.am:$(am__tty_colors)'.
+  red='[0;31m' # Red.
+  grn='[0;32m' # Green.
+  lgn='[1;32m' # Light green.
+  blu='[1;34m' # Blue.
+  mgn='[0;35m' # Magenta.
+  std='[m'     # No color.
+else
+  red= grn= lgn= blu= mgn= std=
+fi
+
+do_exit='rm -f $log_file $trs_file; (exit $st); exit $st'
+trap "st=129; $do_exit" 1
+trap "st=130; $do_exit" 2
+trap "st=141; $do_exit" 13
+trap "st=143; $do_exit" 15
+
+# Test script is run here. We create the file first, then append to it,
+# to ameliorate tests themselves also writing to the log file. Our tests
+# don't, but others can (automake bug#35762).
+: >"$log_file"
+"$@" >>"$log_file" 2>&1
+estatus=$?
+
+if test $enable_hard_errors = no && test $estatus -eq 99; then
+  tweaked_estatus=1
+else
+  tweaked_estatus=$estatus
+fi
+
+case $tweaked_estatus:$expect_failure in
+  0:yes) col=$red res=XPASS recheck=yes gcopy=yes;;
+  0:*)   col=$grn res=PASS  recheck=no  gcopy=no;;
+  77:*)  col=$blu res=SKIP  recheck=no  gcopy=yes;;
+  99:*)  col=$mgn res=ERROR recheck=yes gcopy=yes;;
+  *:yes) col=$lgn res=XFAIL recheck=no  gcopy=yes;;
+  *:*)   col=$red res=FAIL  recheck=yes gcopy=yes;;
+esac
+
+# Report the test outcome and exit status in the logs, so that one can
+# know whether the test passed or failed simply by looking at the '.log'
+# file, without the need of also peaking into the corresponding '.trs'
+# file (automake bug#11814).
+echo "$res $test_name (exit status: $estatus)" >>"$log_file"
+
+# Report outcome to console.
+echo "${col}${res}${std}: $test_name"
+
+# Register the test result, and other relevant metadata.
+echo ":test-result: $res" > $trs_file
+echo ":global-test-result: $res" >> $trs_file
+echo ":recheck: $recheck" >> $trs_file
+echo ":copy-in-global-log: $gcopy" >> $trs_file
+
+# Local Variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC0"
+# time-stamp-end: "; # UTC"
+# End:
Index: /trunk/src/libs/libpng-1.6.45/tests/pngimage-full
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngimage-full	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngimage-full	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngimage --exhaustive --list-combos --log "${srcdir}/contrib/pngsuite/"*.png
Index: /trunk/src/libs/libpng-1.6.45/tests/pngimage-quick
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngimage-quick	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngimage-quick	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngimage --list-combos --log "${srcdir}/contrib/pngsuite/"*.png
Index: /trunk/src/libs/libpng-1.6.45/tests/pngstest
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngstest	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngstest	(revision 107811)
@@ -0,0 +1,54 @@
+#!/bin/sh
+#
+# Usage:
+#
+#  tests/pngstest gamma alpha
+#
+# Run ./pngstest on the PNG files in $srcdir/contrib/testpngs which have the
+# given gamma and opacity:
+#
+#  gamma: one of; linear, 1.8, sRGB, none.
+#  alpha: one of; opaque, tRNS, alpha, none.  'none' is equivalent to !alpha
+#
+# NOTE: the temporary files pngstest generates have the base name gamma-alpha to
+# avoid issues with make -j
+#
+gamma="$1"
+shift
+alpha="$1"
+shift
+args=
+LC_ALL="C" # fix glob sort order to ASCII:
+for f in "${srcdir}/contrib/testpngs/"*.png
+do
+   g=
+   case "$f" in
+      *-linear[.-]*)
+         test "$gamma" = "linear" && g="$f";;
+
+      *-sRGB[.-]*)
+         test "$gamma" = "sRGB" && g="$f";;
+
+      *-1.8[.-]*)
+         test "$gamma" = "1.8" && g="$f";;
+
+      *)
+         test "$gamma" = "none" && g="$f";;
+   esac
+
+   case "$g" in
+      "")
+         :;;
+
+      *-alpha[-.]*)
+         test "$alpha" = "alpha" && args="$args $g";;
+
+      *-tRNS[-.]*)
+         test "$alpha" = "tRNS" -o "$alpha" = "none" && args="$args $g";;
+
+      *)
+         test "$alpha" = "opaque" -o "$alpha" = "none" && args="$args $g";;
+   esac
+done
+# This only works if the arguments don't contain spaces; they don't.
+exec ./pngstest --tmpfile "${gamma}-${alpha}-" --log ${1+"$@"} $args
Index: /trunk/src/libs/libpng-1.6.45/tests/pngstest-1.8
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngstest-1.8	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngstest-1.8	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" 1.8 none
Index: /trunk/src/libs/libpng-1.6.45/tests/pngstest-1.8-alpha
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngstest-1.8-alpha	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngstest-1.8-alpha	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" 1.8 alpha
Index: /trunk/src/libs/libpng-1.6.45/tests/pngstest-linear
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngstest-linear	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngstest-linear	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" linear none
Index: /trunk/src/libs/libpng-1.6.45/tests/pngstest-linear-alpha
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngstest-linear-alpha	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngstest-linear-alpha	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" linear alpha
Index: /trunk/src/libs/libpng-1.6.45/tests/pngstest-none
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngstest-none	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngstest-none	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" none none
Index: /trunk/src/libs/libpng-1.6.45/tests/pngstest-none-alpha
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngstest-none-alpha	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngstest-none-alpha	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" none alpha
Index: /trunk/src/libs/libpng-1.6.45/tests/pngstest-sRGB
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngstest-sRGB	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngstest-sRGB	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" sRGB none
Index: /trunk/src/libs/libpng-1.6.45/tests/pngstest-sRGB-alpha
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngstest-sRGB-alpha	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngstest-sRGB-alpha	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "${srcdir}/tests/pngstest" sRGB alpha
Index: /trunk/src/libs/libpng-1.6.45/tests/pngunknown-IDAT
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngunknown-IDAT	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngunknown-IDAT	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict default=discard IDAT=save "${srcdir}/pngtest.png"
Index: /trunk/src/libs/libpng-1.6.45/tests/pngunknown-discard
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngunknown-discard	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngunknown-discard	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict default=discard "${srcdir}/pngtest.png"
Index: /trunk/src/libs/libpng-1.6.45/tests/pngunknown-if-safe
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngunknown-if-safe	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngunknown-if-safe	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict default=if-safe "${srcdir}/pngtest.png"
Index: /trunk/src/libs/libpng-1.6.45/tests/pngunknown-sAPI
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngunknown-sAPI	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngunknown-sAPI	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict bKGD=save cHRM=save gAMA=save all=discard iCCP=save sBIT=save sRGB=save eXIf=save "${srcdir}/pngtest.png"
Index: /trunk/src/libs/libpng-1.6.45/tests/pngunknown-sTER
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngunknown-sTER	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngunknown-sTER	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict sTER=if-safe "${srcdir}/pngtest.png"
Index: /trunk/src/libs/libpng-1.6.45/tests/pngunknown-save
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngunknown-save	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngunknown-save	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict default=save "${srcdir}/pngtest.png"
Index: /trunk/src/libs/libpng-1.6.45/tests/pngunknown-vpAg
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngunknown-vpAg	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngunknown-vpAg	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngunknown --strict vpAg=if-safe "${srcdir}/pngtest.png"
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-16-to-8
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-16-to-8	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-16-to-8	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-16-to-8
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-alpha-mode
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-alpha-mode	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-alpha-mode	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-alpha-mode
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-background
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-background	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-background	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-background
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-expand16-alpha-mode
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-expand16-alpha-mode	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-expand16-alpha-mode	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-alpha-mode --expand16
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-expand16-background
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-expand16-background	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-expand16-background	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-background --expand16
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-expand16-transform
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-expand16-transform	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-expand16-transform	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-transform --expand16
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-sbit
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-sbit	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-sbit	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-sbit
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-threshold
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-threshold	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-threshold	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-threshold
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-transform
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-transform	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-gamma-transform	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --gamma-transform
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-progressive-interlace-standard
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-progressive-interlace-standard	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-progressive-interlace-standard	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --standard --progressive-read --interlace
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-progressive-size
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-progressive-size	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-progressive-size	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --size --progressive-read
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-progressive-standard
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-progressive-standard	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-progressive-standard	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --standard --progressive-read
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-standard
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-standard	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-standard	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --standard
Index: /trunk/src/libs/libpng-1.6.45/tests/pngvalid-transform
===================================================================
--- /trunk/src/libs/libpng-1.6.45/tests/pngvalid-transform	(revision 107811)
+++ /trunk/src/libs/libpng-1.6.45/tests/pngvalid-transform	(revision 107811)
@@ -0,0 +1,2 @@
+#!/bin/sh
+exec ./pngvalid --strict --transform
