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  1. /****************************************************************************
  2. *
  3. *                            Open Watcom Project
  4. *
  5. *    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
  6. *
  7. *  ========================================================================
  8. *
  9. *    This file contains Original Code and/or Modifications of Original
  10. *    Code as defined in and that are subject to the Sybase Open Watcom
  11. *    Public License version 1.0 (the 'License'). You may not use this file
  12. *    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
  13. *    ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
  14. *    provided with the Original Code and Modifications, and is also
  15. *    available at www.sybase.com/developer/opensource.
  16. *
  17. *    The Original Code and all software distributed under the License are
  18. *    distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  19. *    EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
  20. *    ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
  21. *    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
  22. *    NON-INFRINGEMENT. Please see the License for the specific language
  23. *    governing rights and limitations under the License.
  24. *
  25. *  ========================================================================
  26. *
  27. * Description:  Implementation of snprintf_s() - safe string fmt'd output.
  28. *
  29. ****************************************************************************/
  30.  
  31.  
  32. #include "variety.h"
  33. #include "saferlib.h"
  34. #include "widechar.h"
  35. #include <stdio.h>
  36. #include <stdarg.h>
  37. #include <wchar.h>
  38. #include "printf.h"
  39.  
  40.  
  41. struct buf_limit {
  42.     CHAR_TYPE   *bufptr;
  43.     rsize_t     chars_output;
  44.     rsize_t     max_chars;
  45. };
  46.  
  47. /*
  48.  * buf_putc -- append a character to a string in memory
  49.  */
  50. static slib_callback_t buf_putc; // setup calling convention
  51. static void __SLIB_CALLBACK buf_putc( SPECS __SLIB *specs, int op_char )
  52. {
  53.     struct buf_limit    *info;
  54.  
  55.     info = (struct buf_limit *)specs->_dest;
  56.     if( specs->_output_count < info->max_chars ) {
  57.         *( info->bufptr++ ) = op_char;
  58.         info->chars_output++;
  59.     }
  60.     specs->_output_count++;
  61. }
  62.  
  63.  
  64. _WCRTLINK int __F_NAME(snprintf_s,snwprintf_s)( CHAR_TYPE * __restrict s, rsize_t n,
  65.                                           const CHAR_TYPE * __restrict format, ... )
  66. {
  67.     va_list    arg;
  68.     struct buf_limit    info;
  69.     const char          *msg;
  70.  
  71.     /* First check the critical conditions; if any of those
  72.      * is violated, return immediately and don't touch anything.
  73.      */
  74.     if( __check_constraint_nullptr_msg( msg, s )
  75.      && __check_constraint_maxsize_msg( msg, n )
  76.      && __check_constraint_zero_msg( msg, n ) ) {
  77.  
  78.         /* The buffer looks okay, try doing something useful */
  79.         if( __check_constraint_nullptr_msg( msg, format ) ) {
  80.             int                 len;
  81.  
  82.             info.bufptr       = s;
  83.             info.chars_output = 0;
  84.             info.max_chars    = n - 1;
  85.             msg = NULL;
  86.             va_start( arg, format );
  87.             len = __F_NAME(__prtf_s,__wprtf_s)( &info, format, arg, &msg, buf_putc );
  88.             va_end( arg );
  89.             if( msg == NULL ) {
  90.                 /* No rt-constraint violation while formatting */
  91.                 s[info.chars_output] = NULLCHAR;
  92.                 return( len );
  93.             }
  94.         }
  95.         /* Something went wrong, output buffer will contain empty string */
  96.         *s = NULLCHAR;
  97.     }
  98.     __rtct_fail( __func__, msg, NULL );
  99.     return( -1 );
  100. }
  101.