sal/systools/win32/uwinapi/sntprintf.c

   1 #define _SNPRINTF_DLLIMPORT __declspec( dllexport )
   2
   3 #include <stdarg.h>
   4 #include <stdio.h>
   5
   6 #include <tchar.h>
   7 #include <systools/win32/snprintf.h>
   8
   9 #if defined(_MSC_VER) && (_MSC_VER >= 1400)
  10 #pragma warning(disable:4273)           // inconsistent dll linkage
  11 #endif
  12
  13 #if _MSC_VER < 1300
  14
  15 /*      The non-debug versions of _vscprintf/_scprintf are just calls
  16     to _vsprintf/_sprintf with string buffer pointer set to NULL,
  17     requires MSVCRT version 7.0 */
  18 #ifdef __MINGW32__
  19 static int __cdecl _vsctprintf( const TCHAR *format, va_list ap )
  20 #else
  21 static int __cdecl _vsctprintf( const _TXCHAR *format, va_list ap )
  22 #endif
  23 {
  24     FILE        *fp = _tfopen( _T("NUL"), _T("wb") );
  25
  26     if ( fp )
  27     {
  28         int     retval = _vftprintf( fp, format, ap );
  29         fclose( fp );
  30
  31         return retval;
  32     }
  33
  34     return -1;
  35 }
  36 #endif
  37
  38 /*      This function retrieves the pointer to the last character of a buffer.
  39     That is the pointer to the last character of the buffer that fits
  40     completly into that buffer or the position of the terminating zero.
  41
  42     buffer      Pointer to a _TXCHAR buffer to be examined
  43     count       size of the buffer to be examined
  44
  45     return      The pointer to the last character that fits into the buffer or
  46             NULL if count is zero or count is one and the first byte was a
  47             leading     DBCS character
  48 */
  49
  50 static _TCHAR *GetLastBufferChar( _TCHAR *buffer, size_t count )
  51 {
  52     _TCHAR      *last = NULL;
  53     _TCHAR      *cur = buffer;
  54
  55     while ( (size_t)(cur - buffer) < count )
  56     {
  57         last = cur;
  58
  59         if ( !*last )
  60             break;
  61
  62         cur = _tcsinc(last);
  63     }
  64
  65     return last;
  66 }
  67
  68 /* Implementation of snprintf following the ISO/IEC 9899:1999 (ISO C99) standard */
  69
  70 _SNPRINTF_DLLIMPORT int __cdecl vsntprintf( _TCHAR *buffer, size_t count, const _TCHAR *format, va_list list )
  71 {
  72     int         retval;
  73
  74     /*  First of all call the existing non POSIX standard function assuming
  75         the buffer size will be large enough */
  76
  77     retval = _vsntprintf( buffer, count, format, list );
  78
  79     if ( retval < 0 )
  80     {
  81         /*      If the buffer wasn't large enough ensure that the buffer will be
  82             zero terminated */
  83
  84         _TCHAR  *last = GetLastBufferChar( buffer, count );
  85         if (last )
  86             *last = 0;
  87
  88         /*      Retrieve the count of characters that would have been written
  89             if the buffer were large enough */
  90
  91         retval = _vsctprintf( format, list );
  92     }
  93     else if ( (size_t)retval == count && count )
  94     {
  95         /*      If the buffer was large enough but not large enough for the trailing
  96             zero make the buffer zero terminated */
  97
  98         _TCHAR  *last = GetLastBufferChar( buffer, count );
  99         if (last )
 100             *last = 0;
 101     }
 102
 103     return retval;
 104 }
 105
 106 /* Implementation of snprintf following the ISO/IEC 9899:1999 (ISO C99) standard */
 107
 108 _SNPRINTF_DLLIMPORT int __cdecl sntprintf( _TCHAR *buffer, size_t count, const _TCHAR *format, ... )
 109 {
 110     va_list     list;
 111     int         retval;
 112
 113     va_start( list, format );
 114     retval = vsntprintf( buffer, count, format, list );
 115     va_end( list );
 116
 117     return retval;
 118 }