VirtualBox

source: vbox/trunk/include/VBox/com/string.h@ 18216

Last change on this file since 18216 was 18148, checked in by vboxsync, 16 years ago

Main: don't call length() twice

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1/* $Id: string.h 18148 2009-03-23 16:10:48Z vboxsync $ */
2
3/** @file
4 * MS COM / XPCOM Abstraction Layer:
5 * Smart string classes declaration
6 */
7
8/*
9 * Copyright (C) 2006-2009 Sun Microsystems, Inc.
10 *
11 * This file is part of VirtualBox Open Source Edition (OSE), as
12 * available from http://www.virtualbox.org. This file is free software;
13 * you can redistribute it and/or modify it under the terms of the GNU
14 * General Public License (GPL) as published by the Free Software
15 * Foundation, in version 2 as it comes in the "COPYING" file of the
16 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
17 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
18 *
19 * The contents of this file may alternatively be used under the terms
20 * of the Common Development and Distribution License Version 1.0
21 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
22 * VirtualBox OSE distribution, in which case the provisions of the
23 * CDDL are applicable instead of those of the GPL.
24 *
25 * You may elect to license modified versions of this file under the
26 * terms and conditions of either the GPL or the CDDL or both.
27 *
28 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
29 * Clara, CA 95054 USA or visit http://www.sun.com if you need
30 * additional information or have any questions.
31 */
32
33#ifndef ___VBox_com_string_h
34#define ___VBox_com_string_h
35
36/* Make sure all the stdint.h macros are included - must come first! */
37#ifndef __STDC_LIMIT_MACROS
38# define __STDC_LIMIT_MACROS
39#endif
40#ifndef __STDC_CONSTANT_MACROS
41# define __STDC_CONSTANT_MACROS
42#endif
43
44#if defined (VBOX_WITH_XPCOM)
45# include <nsMemory.h>
46#endif
47
48#include "VBox/com/defs.h"
49#include "VBox/com/assert.h"
50
51#include <iprt/string.h>
52#include <iprt/cpputils.h>
53#include <iprt/alloc.h>
54
55namespace com
56{
57
58class Utf8Str;
59
60/**
61 * Helper class that represents the |BSTR| type and hides platform-specific
62 * implementation details.
63 *
64 * This class uses COM/XPCOM-provided memory management routines to allocate
65 * and free string buffers. This makes it possible to:
66 * - use it as a type of member variables of COM/XPCOM components and pass
67 * their values to callers through component methods' output parameters
68 * using the #cloneTo() operation;
69 * - adopt (take ownership of) string buffers returned in output parameters
70 * of COM methods using the #asOutParam() operation and correctly free them
71 * afterwards.
72 */
73class Bstr
74{
75public:
76
77 typedef BSTR String;
78 typedef CBSTR ConstString;
79
80 Bstr () : bstr (NULL) {}
81
82 Bstr (const Bstr &that) : bstr (NULL) { raw_copy (bstr, that.bstr); }
83 Bstr (CBSTR that) : bstr (NULL) { raw_copy (bstr, that); }
84
85#if defined (VBOX_WITH_XPCOM)
86 Bstr (const wchar_t *that) : bstr (NULL)
87 {
88 AssertCompile (sizeof (wchar_t) == sizeof (OLECHAR));
89 raw_copy (bstr, (CBSTR) that);
90 }
91#endif
92
93 Bstr (const Utf8Str &that);
94 Bstr (const char *that);
95
96 /** Shortcut that calls #alloc(aSize) right after object creation. */
97 Bstr (size_t aSize) : bstr (NULL) { alloc (aSize); }
98
99 ~Bstr () { setNull(); }
100
101 Bstr &operator = (const Bstr &that) { safe_assign (that.bstr); return *this; }
102 Bstr &operator = (CBSTR that) { safe_assign (that); return *this; }
103
104 Bstr &operator = (const Utf8Str &that);
105 Bstr &operator = (const char *that);
106
107 Bstr &setNull()
108 {
109 if (bstr)
110 {
111 ::SysFreeString (bstr);
112 bstr = NULL;
113 }
114 return *this;
115 }
116
117 Bstr &setNullIfEmpty()
118 {
119 if (bstr && *bstr == 0)
120 {
121 ::SysFreeString (bstr);
122 bstr = NULL;
123 }
124 return *this;
125 }
126
127 /**
128 * Allocates memory for a string capable to store \a aSize - 1 characters;
129 * in other words, aSize includes the terminating zero character. If \a aSize
130 * is zero, or if a memory allocation error occurs, this object will become null.
131 */
132 Bstr &alloc (size_t aSize)
133 {
134 setNull();
135 if (aSize)
136 {
137 unsigned int size = (unsigned int) aSize; Assert (size == aSize);
138 bstr = ::SysAllocStringLen (NULL, size - 1);
139 if (bstr)
140 bstr [0] = 0;
141 }
142 return *this;
143 }
144
145 int compare (CBSTR str) const
146 {
147 return ::RTUtf16Cmp ((PRTUTF16) bstr, (PRTUTF16) str);
148 }
149
150 int compare (BSTR str) const
151 {
152 return ::RTUtf16Cmp ((PRTUTF16) bstr, (PRTUTF16) str);
153 }
154
155 bool operator == (const Bstr &that) const { return !compare (that.bstr); }
156 bool operator != (const Bstr &that) const { return !!compare (that.bstr); }
157 bool operator == (CBSTR that) const { return !compare (that); }
158 bool operator == (BSTR that) const { return !compare (that); }
159
160#if defined (VBOX_WITH_XPCOM)
161 bool operator != (const wchar_t *that) const
162 {
163 AssertCompile (sizeof (wchar_t) == sizeof (OLECHAR));
164 return !!compare ((CBSTR) that);
165 }
166 bool operator == (const wchar_t *that) const
167 {
168 AssertCompile (sizeof (wchar_t) == sizeof (OLECHAR));
169 return !compare ((CBSTR) that);
170 }
171#endif
172
173 bool operator != (CBSTR that) const { return !!compare (that); }
174 bool operator != (BSTR that) const { return !!compare (that); }
175 bool operator < (const Bstr &that) const { return compare (that.bstr) < 0; }
176 bool operator < (CBSTR that) const { return compare (that) < 0; }
177 bool operator < (BSTR that) const { return compare (that) < 0; }
178#if defined (VBOX_WITH_XPCOM)
179 bool operator < (const wchar_t *that) const
180 {
181 AssertCompile (sizeof (wchar_t) == sizeof (OLECHAR));
182 return compare ((CBSTR) that) < 0;
183 }
184#endif
185
186 int compareIgnoreCase (CBSTR str) const
187 {
188 return ::RTUtf16LocaleICmp (bstr, str);
189 }
190
191 bool isNull() const { return bstr == NULL; }
192 operator bool() const { return !isNull(); }
193
194 bool isEmpty() const { return isNull() || *bstr == 0; }
195
196 size_t length() const { return isNull() ? 0 : ::RTUtf16Len ((PRTUTF16) bstr); }
197
198 /** Intended to to pass instances as |CBSTR| input parameters to methods. */
199 operator CBSTR () const { return bstr; }
200
201 /**
202 * Intended to to pass instances as |BSTR| input parameters to methods.
203 * Note that we have to provide this mutable BSTR operator since in MS COM
204 * input BSTR parameters of interface methods are not const.
205 */
206 operator BSTR () { return bstr; }
207
208 /**
209 * The same as operator CBSTR(), but for situations where the compiler
210 * cannot typecast implicitly (for example, in printf() argument list).
211 */
212 CBSTR raw() const { return bstr; }
213
214 /**
215 * Returns a non-const raw pointer that allows to modify the string directly.
216 * @warning
217 * Be sure not to modify data beyond the allocated memory! The
218 * guaranteed size of the allocated memory is at least #length()
219 * bytes after creation and after every assignment operation.
220 */
221 BSTR mutableRaw() { return bstr; }
222
223 /**
224 * Intended to assign copies of instances to |BSTR| out parameters from
225 * within the interface method. Transfers the ownership of the duplicated
226 * string to the caller.
227 */
228 const Bstr &cloneTo (BSTR *pstr) const
229 {
230 if (pstr)
231 {
232 *pstr = NULL;
233 raw_copy (*pstr, bstr);
234 }
235 return *this;
236 }
237
238 /**
239 * Intended to assign instances to |BSTR| out parameters from within the
240 * interface method. Transfers the ownership of the original string to the
241 * caller and resets the instance to null.
242 *
243 * As opposed to cloneTo(), this method doesn't create a copy of the
244 * string.
245 */
246 Bstr &detachTo (BSTR *pstr)
247 {
248 *pstr = bstr;
249 bstr = NULL;
250 return *this;
251 }
252
253 /**
254 * Intended to assign copies of instances to |char *| out parameters from
255 * within the interface method. Transfers the ownership of the duplicated
256 * string to the caller.
257 */
258 const Bstr &cloneTo (char **pstr) const;
259
260 /**
261 * Intended to pass instances as |BSTR| out parameters to methods.
262 * Takes the ownership of the returned data.
263 */
264 BSTR *asOutParam() { setNull(); return &bstr; }
265
266 /**
267 * Static immutable null object. May be used for comparison purposes.
268 */
269 static const Bstr Null;
270
271protected:
272
273 void safe_assign (CBSTR str)
274 {
275 if (bstr != str)
276 {
277 setNull();
278 raw_copy (bstr, str);
279 }
280 }
281
282 inline static void raw_copy (BSTR &ls, CBSTR rs)
283 {
284 if (rs)
285 ls = ::SysAllocString ((const OLECHAR *) rs);
286 }
287
288 inline static void raw_copy (BSTR &ls, const char *rs)
289 {
290 if (rs)
291 {
292 PRTUTF16 s = NULL;
293 ::RTStrToUtf16 (rs, &s);
294 raw_copy (ls, (BSTR) s);
295 ::RTUtf16Free (s);
296 }
297 }
298
299 BSTR bstr;
300
301 friend class Utf8Str; /* to access our raw_copy() */
302};
303
304/* symmetric compare operators */
305inline bool operator== (CBSTR l, const Bstr &r) { return r.operator== (l); }
306inline bool operator!= (CBSTR l, const Bstr &r) { return r.operator!= (l); }
307inline bool operator== (BSTR l, const Bstr &r) { return r.operator== (l); }
308inline bool operator!= (BSTR l, const Bstr &r) { return r.operator!= (l); }
309
310////////////////////////////////////////////////////////////////////////////////
311
312/**
313 * Helper class that represents UTF8 (|char *|) strings. Useful in
314 * conjunction with Bstr to simplify conversions between UTF16 (|BSTR|)
315 * and UTF8.
316 *
317 * This class uses COM/XPCOM-provided memory management routines to allocate
318 * and free string buffers. This makes it possible to:
319 * - use it as a type of member variables of COM/XPCOM components and pass
320 * their values to callers through component methods' output parameters
321 * using the #cloneTo() operation;
322 * - adopt (take ownership of) string buffers returned in output parameters
323 * of COM methods using the #asOutParam() operation and correctly free them
324 * afterwards.
325 */
326class Utf8Str
327{
328public:
329
330 enum CaseSensitivity
331 {
332 CaseSensitive,
333 CaseInsensitive
334 };
335
336 typedef char *String;
337 typedef const char *ConstString;
338
339 Utf8Str () : str (NULL) {}
340
341 Utf8Str (const Utf8Str &that) : str (NULL) { raw_copy (str, that.str); }
342 Utf8Str (const char *that) : str (NULL) { raw_copy (str, that); }
343
344 Utf8Str (const Bstr &that) : str (NULL) { raw_copy (str, that); }
345 Utf8Str (CBSTR that) : str (NULL) { raw_copy (str, that); }
346
347 /** Shortcut that calls #alloc(aSize) right after object creation. */
348 Utf8Str (size_t aSize) : str (NULL) { alloc(aSize); }
349
350 virtual ~Utf8Str () { setNull(); }
351
352 Utf8Str &operator = (const Utf8Str &that) { safe_assign (that.str); return *this; }
353 Utf8Str &operator = (const char *that) { safe_assign (that); return *this; }
354
355 Utf8Str &operator = (const Bstr &that)
356 {
357 setNull();
358 raw_copy (str, that);
359 return *this;
360 }
361 Utf8Str &operator = (CBSTR that)
362 {
363 setNull();
364 raw_copy (str, that);
365 return *this;
366 }
367
368 Utf8Str &setNull()
369 {
370 if (str)
371 {
372#if !defined (VBOX_WITH_XPCOM)
373 ::RTStrFree (str);
374#else
375 nsMemory::Free (str);
376#endif
377 str = NULL;
378 }
379 return *this;
380 }
381
382 Utf8Str &setNullIfEmpty()
383 {
384 if (str && *str == 0)
385 {
386#if !defined (VBOX_WITH_XPCOM)
387 ::RTStrFree (str);
388#else
389 nsMemory::Free (str);
390#endif
391 str = NULL;
392 }
393 return *this;
394 }
395
396 /**
397 * Allocates memory for a string capable to store \a aSize - 1 bytes (not characters!);
398 * in other words, aSize includes the terminating zero character. If \a aSize
399 * is zero, or if a memory allocation error occurs, this object will become null.
400 */
401 Utf8Str &alloc (size_t aSize)
402 {
403 setNull();
404 if (aSize)
405 {
406#if !defined (VBOX_WITH_XPCOM)
407 str = (char *) ::RTMemTmpAlloc (aSize);
408#else
409 str = (char *) nsMemory::Alloc (aSize);
410#endif
411 if (str)
412 str [0] = 0;
413 }
414 return *this;
415 }
416
417 void append(const Utf8Str &that)
418 {
419 size_t cbThis = length();
420 size_t cbThat = that.length();
421
422 if (cbThat)
423 {
424 size_t cbBoth = cbThis + cbThat + 1;
425
426 // @todo optimize with realloc() once the memory management is fixed
427 char *pszTemp;
428#if !defined (VBOX_WITH_XPCOM)
429 pszTemp = (char*)::RTMemTmpAlloc(cbBoth);
430#else
431 pszTemp = (char*)nsMemory::Alloc(cbBoth);
432#endif
433 if (str)
434 {
435 memcpy(pszTemp, str, cbThis);
436 setNull();
437 }
438 if (that.str)
439 memcpy(pszTemp + cbThis, that.str, cbThat);
440 pszTemp[cbThis + cbThat] = '\0';
441
442 str = pszTemp;
443 }
444 }
445
446 int compare (const char *pcsz, CaseSensitivity cs = CaseSensitive) const
447 {
448 if (str == pcsz)
449 return 0;
450 if (str == NULL)
451 return -1;
452 if (pcsz == NULL)
453 return 1;
454
455 if (cs == CaseSensitive)
456 return ::RTStrCmp(str, pcsz);
457 else
458 return ::RTStrICmp(str, pcsz);
459 }
460
461 int compare (const Utf8Str &that, CaseSensitivity cs = CaseSensitive) const
462 {
463 return compare (that.str, cs);
464 }
465
466 bool operator == (const Utf8Str &that) const { return !compare (that); }
467 bool operator != (const Utf8Str &that) const { return !!compare (that); }
468 bool operator == (const char *that) const { return !compare (that); }
469 bool operator != (const char *that) const { return !!compare (that); }
470 bool operator < (const Utf8Str &that) const { return compare (that) < 0; }
471 bool operator < (const char *that) const { return compare (that) < 0; }
472
473 bool endsWith (const Utf8Str &that, CaseSensitivity cs = CaseSensitive) const
474 {
475 if (isNull() || that.isNull())
476 return false;
477
478 size_t l1 = length();
479 size_t l2 = that.length();
480 if (l1 < l2)
481 return false;
482
483 size_t l = l1 - l2;
484 if (cs == CaseSensitive)
485 return ::RTStrCmp(&str[l], that.str) == 0;
486 else
487 return ::RTStrICmp(&str[l], that.str) == 0;
488 }
489
490 bool startsWith (const Utf8Str &that, CaseSensitivity cs = CaseSensitive) const
491 {
492 if (isNull() || that.isNull())
493 return false;
494
495 size_t l1 = length();
496 size_t l2 = that.length();
497 if (l1 < l2)
498 return false;
499
500 if (cs == CaseSensitive)
501 return ::RTStrNCmp(str, that.str, l2) == 0;
502 else
503 return ::RTStrNICmp(str, that.str, l2) == 0;
504 }
505
506 bool isNull() const { return str == NULL; }
507 operator bool() const { return !isNull(); }
508
509 bool isEmpty() const { return isNull() || *str == 0; }
510
511 size_t length() const { return isNull() ? 0 : ::strlen (str); }
512
513 /** Intended to to pass instances as input (|char *|) parameters to methods. */
514 operator const char *() const { return str; }
515
516 /** The same as operator const char *(), but for situations where the compiler
517 cannot typecast implicitly (for example, in printf() argument list). */
518 const char *raw() const { return str; }
519
520 /** The same as operator const char *(), but for situations where the compiler
521 cannot typecast implicitly (for example, in printf() argument list). */
522 const char *c_str() const { return str; }
523
524 /**
525 * Returns a non-const raw pointer that allows to modify the string directly.
526 * @warning
527 * Be sure not to modify data beyond the allocated memory! The
528 * guaranteed size of the allocated memory is at least #length()
529 * bytes after creation and after every assignment operation.
530 */
531 char *mutableRaw() { return str; }
532
533 /**
534 * Intended to assign instances to |char *| out parameters from within the
535 * interface method. Transfers the ownership of the duplicated string to the
536 * caller.
537 */
538 const Utf8Str &cloneTo (char **pstr) const
539 {
540 if (pstr)
541 {
542 *pstr = NULL;
543 raw_copy (*pstr, str);
544 }
545 return *this;
546 }
547
548 /**
549 * Intended to assign instances to |char *| out parameters from within the
550 * interface method. Transfers the ownership of the original string to the
551 * caller and resets the instance to null.
552 *
553 * As opposed to cloneTo(), this method doesn't create a copy of the
554 * string.
555 */
556 Utf8Str &detachTo (char **pstr)
557 {
558 *pstr = str;
559 str = NULL;
560 return *this;
561 }
562
563 /**
564 * Intended to assign instances to |BSTR| out parameters from within the
565 * interface method. Transfers the ownership of the duplicated string to the
566 * caller.
567 */
568 const Utf8Str &cloneTo (BSTR *pstr) const
569 {
570 if (pstr)
571 {
572 *pstr = NULL;
573 Bstr::raw_copy (*pstr, str);
574 }
575 return *this;
576 }
577
578 static const size_t npos;
579
580 /**
581 * Looks for pcszFind in "this" starting at "pos" and returns its position,
582 * counting from the beginning of "this" at 0. Returns npos if not found.
583 */
584 size_t find(const char *pcszFind, size_t pos = 0) const;
585
586 /**
587 * Returns a substring of "this" as a new Utf8Str. Works exactly like
588 * its equivalent in std::string except that this interprets pos and n
589 * as UTF-8 codepoints instead of bytes. With the default parameters "0"
590 * and "npos", this always copies the entire string.
591 * @param pos Index of first codepoint to copy from "this", counting from 0.
592 * @param n Number of codepoints to copy, starting with the one at "pos".
593 */
594 Utf8Str substr(size_t pos = 0, size_t n = npos) const;
595
596 /**
597 * Attempts to convert the member string into an 32-bit integer.
598 *
599 * @returns 32-bit unsigned number on success.
600 * @returns 0 on failure.
601 */
602 int toInt32() const
603 {
604 return RTStrToInt32(str);
605 }
606
607 /**
608 * Attempts to convert the member string into an unsigned 32-bit integer.
609 *
610 * @returns 32-bit unsigned number on success.
611 * @returns 0 on failure.
612 */
613 int toUInt32() const
614 {
615 return RTStrToUInt32(str);
616 }
617
618 /**
619 * Attempts to convert the member string into an 64-bit integer.
620 *
621 * @returns 64-bit unsigned number on success.
622 * @returns 0 on failure.
623 */
624 int64_t toInt64() const
625 {
626 return RTStrToInt64(str);
627 }
628
629 /**
630 * Attempts to convert the member string into an unsigned 64-bit integer.
631 *
632 * @returns 64-bit unsigned number on success.
633 * @returns 0 on failure.
634 */
635 uint64_t toUInt64() const
636 {
637 return RTStrToUInt64(str);
638 }
639
640 /**
641 * Attempts to convert the member string into an unsigned 64-bit integer.
642 * @return IPRT error code.
643 * @param i Output buffer.
644 */
645 int toInt(uint64_t &i) const;
646
647 /**
648 * Attempts to convert the member string into an unsigned 32-bit integer.
649 * @return IPRT error code.
650 * @param i Output buffer.
651 */
652 int toInt(uint32_t &i) const;
653
654 /**
655 * Intended to pass instances as out (|char **|) parameters to methods.
656 * Takes the ownership of the returned data.
657 */
658 char **asOutParam() { setNull(); return &str; }
659
660 /**
661 * Static immutable null object. May be used for comparison purposes.
662 */
663 static const Utf8Str Null;
664
665protected:
666
667 void safe_assign (const char *s)
668 {
669 if (str != s)
670 {
671 setNull();
672 raw_copy (str, s);
673 }
674 }
675
676 inline static void raw_copy (char *&ls, const char *rs)
677 {
678 if (rs)
679#if !defined (VBOX_WITH_XPCOM)
680 ::RTStrDupEx (&ls, rs);
681#else
682 ls = (char *) nsMemory::Clone (rs, strlen (rs) + 1);
683#endif
684 }
685
686 inline static void raw_copy (char *&ls, CBSTR rs)
687 {
688 if (rs)
689 {
690#if !defined (VBOX_WITH_XPCOM)
691 ::RTUtf16ToUtf8 ((PRTUTF16) rs, &ls);
692#else
693 char *s = NULL;
694 ::RTUtf16ToUtf8 ((PRTUTF16) rs, &s);
695 raw_copy (ls, s);
696 ::RTStrFree (s);
697#endif
698 }
699 }
700
701 char *str;
702
703 friend class Bstr; /* to access our raw_copy() */
704};
705
706// symmetric compare operators
707inline bool operator== (const char *l, const Utf8Str &r) { return r.operator== (l); }
708inline bool operator!= (const char *l, const Utf8Str &r) { return r.operator!= (l); }
709
710// work around error C2593 of the stupid MSVC 7.x ambiguity resolver
711WORKAROUND_MSVC7_ERROR_C2593_FOR_BOOL_OP (Bstr)
712WORKAROUND_MSVC7_ERROR_C2593_FOR_BOOL_OP (Utf8Str)
713
714////////////////////////////////////////////////////////////////////////////////
715
716// inlined Bstr members that depend on Utf8Str
717
718inline Bstr::Bstr (const Utf8Str &that) : bstr (NULL) { raw_copy (bstr, that); }
719inline Bstr::Bstr (const char *that) : bstr (NULL) { raw_copy (bstr, that); }
720
721inline Bstr &Bstr::operator = (const Utf8Str &that)
722{
723 setNull();
724 raw_copy (bstr, that);
725 return *this;
726}
727inline Bstr &Bstr::operator = (const char *that)
728{
729 setNull();
730 raw_copy (bstr, that);
731 return *this;
732}
733
734inline const Bstr &Bstr::cloneTo (char **pstr) const
735{
736 if (pstr) {
737 *pstr = NULL;
738 Utf8Str::raw_copy (*pstr, bstr);
739 }
740 return *this;
741}
742
743////////////////////////////////////////////////////////////////////////////////
744
745/**
746 * This class is a printf-like formatter for Utf8Str strings. Its purpose is
747 * to construct Utf8Str objects from a format string and a list of arguments
748 * for the format string.
749 *
750 * The usage of this class is like the following:
751 * <code>
752 * Utf8StrFmt string ("program name = %s", argv[0]);
753 * </code>
754 */
755class Utf8StrFmt : public Utf8Str
756{
757public:
758
759 /**
760 * Constructs a new string given the format string and the list
761 * of the arguments for the format string.
762 *
763 * @param format printf-like format string (in UTF-8 encoding)
764 * @param ... list of the arguments for the format string
765 */
766 explicit Utf8StrFmt (const char *format, ...)
767 {
768 va_list args;
769 va_start (args, format);
770 init (format, args);
771 va_end (args);
772 }
773
774protected:
775
776 Utf8StrFmt() {}
777
778 void init (const char *format, va_list args);
779
780private:
781
782 static DECLCALLBACK(size_t) strOutput (void *pvArg, const char *pachChars,
783 size_t cbChars);
784};
785
786/**
787 * This class is a vprintf-like formatter for Utf8Str strings. It is
788 * identical to Utf8StrFmt except that its constructor takes a va_list
789 * argument instead of ellipsis.
790 *
791 * Note that a separate class is necessary because va_list is defined as
792 * |char *| on most platforms. For this reason, if we had two overloaded
793 * constructors in Utf8StrFmt (one taking ellipsis and another one taking
794 * va_list) then composing a constructor call using exactly two |char *|
795 * arguments would cause the compiler to use the va_list overload instead of
796 * the ellipsis one which is obviously wrong. The compiler would choose
797 * va_list because ellipsis has the lowest rank when it comes to resolving
798 * overloads, as opposed to va_list which is an exact match for |char *|.
799 */
800class Utf8StrFmtVA : public Utf8StrFmt
801{
802public:
803
804 /**
805 * Constructs a new string given the format string and the list
806 * of the arguments for the format string.
807 *
808 * @param format printf-like format string (in UTF-8 encoding)
809 * @param args list of arguments for the format string
810 */
811 Utf8StrFmtVA (const char *format, va_list args) { init (format, args); }
812};
813
814/**
815 * The BstrFmt class is a shortcut to <tt>Bstr (Utf8StrFmt (...))</tt>.
816 */
817class BstrFmt : public Bstr
818{
819public:
820
821 /**
822 * Constructs a new string given the format string and the list of the
823 * arguments for the format string.
824 *
825 * @param aFormat printf-like format string (in UTF-8 encoding).
826 * @param ... List of the arguments for the format string.
827 */
828 explicit BstrFmt (const char *aFormat, ...)
829 {
830 va_list args;
831 va_start (args, aFormat);
832 raw_copy (bstr, Utf8StrFmtVA (aFormat, args));
833 va_end (args);
834 }
835};
836
837/**
838 * The BstrFmtVA class is a shortcut to <tt>Bstr (Utf8StrFmtVA (...))</tt>.
839 */
840class BstrFmtVA : public Bstr
841{
842public:
843
844 /**
845 * Constructs a new string given the format string and the list of the
846 * arguments for the format string.
847 *
848 * @param aFormat printf-like format string (in UTF-8 encoding).
849 * @param aArgs List of arguments for the format string
850 */
851 BstrFmtVA (const char *aFormat, va_list aArgs)
852 {
853 raw_copy (bstr, Utf8StrFmtVA (aFormat, aArgs));
854 }
855};
856
857} /* namespace com */
858
859#endif /* ___VBox_com_string_h */
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