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      1 // Copyright (c) 2006, Google Inc.
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are
      6 // met:
      7 //
      8 //     * Redistributions of source code must retain the above copyright
      9 // notice, this list of conditions and the following disclaimer.
     10 //     * Redistributions in binary form must reproduce the above
     11 // copyright notice, this list of conditions and the following disclaimer
     12 // in the documentation and/or other materials provided with the
     13 // distribution.
     14 //     * Neither the name of Google Inc. nor the names of its
     15 // contributors may be used to endorse or promote products derived from
     16 // this software without specific prior written permission.
     17 //
     18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29 
     30 // string_utils-inl.h: Safer string manipulation on Windows, supporting
     31 // pre-MSVC8 environments.
     32 
     33 #ifndef COMMON_WINDOWS_STRING_UTILS_INL_H_
     34 #define COMMON_WINDOWS_STRING_UTILS_INL_H_
     35 
     36 #include <stdarg.h>
     37 #include <wchar.h>
     38 
     39 #include <string>
     40 
     41 // The "ll" printf format size specifier corresponding to |long long| was
     42 // intrudced in MSVC8.  Earlier versions did not provide this size specifier,
     43 // but "I64" can be used to print 64-bit types.  Don't use "I64" where "ll"
     44 // is available, in the event of oddball systems where |long long| is not
     45 // 64 bits wide.
     46 #if _MSC_VER >= 1400  // MSVC 2005/8
     47 #define WIN_STRING_FORMAT_LL "ll"
     48 #else  // MSC_VER >= 1400
     49 #define WIN_STRING_FORMAT_LL "I64"
     50 #endif  // MSC_VER >= 1400
     51 
     52 // A nonconforming version of swprintf, without the length argument, was
     53 // included with the CRT prior to MSVC8.  Although a conforming version was
     54 // also available via an overload, it is not reliably chosen.  _snwprintf
     55 // behaves as a standards-confirming swprintf should, so force the use of
     56 // _snwprintf when using older CRTs.
     57 #if _MSC_VER < 1400  // MSVC 2005/8
     58 #define swprintf _snwprintf
     59 #else
     60 // For MSVC8 and newer, swprintf_s is the recommended method. Conveniently,
     61 // it takes the same argument list as swprintf.
     62 #define swprintf swprintf_s
     63 #endif  // MSC_VER < 1400
     64 
     65 namespace google_breakpad {
     66 
     67 using std::string;
     68 using std::wstring;
     69 
     70 class WindowsStringUtils {
     71  public:
     72   // Roughly equivalent to MSVC8's wcscpy_s, except pre-MSVC8, this does
     73   // not fail if source is longer than destination_size.  The destination
     74   // buffer is always 0-terminated.
     75   static void safe_wcscpy(wchar_t *destination, size_t destination_size,
     76                           const wchar_t *source);
     77 
     78   // Roughly equivalent to MSVC8's wcsncpy_s, except that _TRUNCATE cannot
     79   // be passed directly, and pre-MSVC8, this will not fail if source or count
     80   // are longer than destination_size.  The destination buffer is always
     81   // 0-terminated.
     82   static void safe_wcsncpy(wchar_t *destination, size_t destination_size,
     83                            const wchar_t *source, size_t count);
     84 
     85   // Performs multi-byte to wide character conversion on C++ strings, using
     86   // mbstowcs_s (MSVC8) or mbstowcs (pre-MSVC8).  Returns false on failure,
     87   // without setting wcs.
     88   static bool safe_mbstowcs(const string &mbs, wstring *wcs);
     89 
     90   // The inverse of safe_mbstowcs.
     91   static bool safe_wcstombs(const wstring &wcs, string *mbs);
     92 
     93   // Returns the base name of a file, e.g. strips off the path.
     94   static wstring GetBaseName(const wstring &filename);
     95 
     96  private:
     97   // Disallow instantiation and other object-based operations.
     98   WindowsStringUtils();
     99   WindowsStringUtils(const WindowsStringUtils&);
    100   ~WindowsStringUtils();
    101   void operator=(const WindowsStringUtils&);
    102 };
    103 
    104 // static
    105 inline void WindowsStringUtils::safe_wcscpy(wchar_t *destination,
    106                                             size_t destination_size,
    107                                             const wchar_t *source) {
    108 #if _MSC_VER >= 1400  // MSVC 2005/8
    109   wcscpy_s(destination, destination_size, source);
    110 #else  // _MSC_VER >= 1400
    111   // Pre-MSVC 2005/8 doesn't have wcscpy_s.  Simulate it with wcsncpy.
    112   // wcsncpy doesn't 0-terminate the destination buffer if the source string
    113   // is longer than size.  Ensure that the destination is 0-terminated.
    114   wcsncpy(destination, source, destination_size);
    115   if (destination && destination_size)
    116     destination[destination_size - 1] = 0;
    117 #endif  // _MSC_VER >= 1400
    118 }
    119 
    120 // static
    121 inline void WindowsStringUtils::safe_wcsncpy(wchar_t *destination,
    122                                              size_t destination_size,
    123                                              const wchar_t *source,
    124                                              size_t count) {
    125 #if _MSC_VER >= 1400  // MSVC 2005/8
    126   wcsncpy_s(destination, destination_size, source, count);
    127 #else  // _MSC_VER >= 1400
    128   // Pre-MSVC 2005/8 doesn't have wcsncpy_s.  Simulate it with wcsncpy.
    129   // wcsncpy doesn't 0-terminate the destination buffer if the source string
    130   // is longer than size.  Ensure that the destination is 0-terminated.
    131   if (destination_size < count)
    132     count = destination_size;
    133 
    134   wcsncpy(destination, source, count);
    135   if (destination && count)
    136     destination[count - 1] = 0;
    137 #endif  // _MSC_VER >= 1400
    138 }
    139 
    140 }  // namespace google_breakpad
    141 
    142 #endif  // COMMON_WINDOWS_STRING_UTILS_INL_H_
    143