Changeset 6421 in vbox

Timestamp:

Jan 21, 2008 5:48:46 PM (17 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

27387

Message:

iprt: added RTFileGetMaxSize()

Location:

trunk

Files:

• include/iprt/file.h (modified) (1 diff)
• src/VBox/Runtime/r3/fileio.cpp (modified) (1 diff)
• src/VBox/Runtime/testcase/tstFile.cpp (modified) (1 diff)

trunk/include/iprt/file.h

@@ -266 +266 @@
 
 /**
+ * Determine the maximum file size depending on the file system the file is stored on.
+ */
+RTR3DECL(uint64_t) RTFileGetMaxSize(RTFILE File);
+
+/**
  * Gets the current file position.
  *

trunk/src/VBox/Runtime/r3/fileio.cpp

@@ -215 +215 @@
     AssertMsgFailed(("RTFileSeek(%d) -> %d\n", File, rc));
     return ~0ULL;
+}
+
+
+/**
+ * Determine the maximum file size. Tested on Windows and Linux.
+ */
+RTR3DECL(uint64_t)  RTFileGetMaxSize(RTFILE File)
+{
+    uint64_t offLow  =       0;
+    uint64_t offHigh = 8 * _1T; /* we don't need bigger files */
+    uint64_t offOld  = RTFileTell(File);
+
+    for (;;)
+    {
+        uint64_t interval = (offHigh - offLow) >> 1;
+        if (interval == 0)
+        {
+            RTFileSeek(File, offOld, RTFILE_SEEK_BEGIN, NULL);
+            return offLow;
+        }
+        if (RT_FAILURE(RTFileSeek(File, offLow + interval, RTFILE_SEEK_BEGIN, NULL)))
+            offHigh = offLow + interval;
+        else
+            offLow  = offLow + interval;
+    }
 }
 

trunk/src/VBox/Runtime/testcase/tstFile.cpp

@@ -49 +49 @@
         return 1;
     }
+
+    RTPrintf("Maximum file size is %lld bytes.\n", RTFileGetMaxSize(File));
 
     /* grow file beyond 2G */