reactos/lib/sdk/crt/string/_mbstrnlen.c

   1 /*
   2  * COPYRIGHT:         See COPYING in the top level directory
   3  * PROJECT:           ReactOS CRT
   4  * PURPOSE:           Implementation of _mbstrnlen
   5  * FILE:              lib/sdk/crt/string/_mbstrnlen.c
   6  * PROGRAMMER:        Timo Kreuzer
   7  */
   8
   9 #include <precomp.h>
  10 #include <mbctype.h>
  11 #include <specstrings.h>
  12
  13 _Success_(return>0)
  14 _Check_return_
  15 _CRTIMP
  16 size_t
  17 __cdecl
  18 _mbstrnlen(
  19     _In_z_ const char *pmbstr,
  20     _In_ size_t cjMaxLen)
  21 {
  22     size_t cchCount = 0;
  23     unsigned char jMbsByte;
  24
  25     /* Check parameters */
  26     if (!MSVCRT_CHECK_PMT((pmbstr != 0)) && (cjMaxLen <= INT_MAX))
  27     {
  28         _set_errno(EINVAL);
  29         return -1;
  30     }
  31
  32     /* Loop while we have bytes to process */
  33     while (cjMaxLen-- > 0)
  34     {
  35         /* Get next mb byte */
  36         jMbsByte = *pmbstr++;
  37
  38         /* If this is 0, we're done */
  39         if (jMbsByte == 0) break;
  40
  41         /* if this is a lead byte, continue with next char */
  42         if (_ismbblead(jMbsByte))
  43         {
  44             // FIXME: check if this is a valid char.
  45             continue;
  46         }
  47
  48         /* Count this character */
  49         cchCount++;
  50     }
  51
  52     return cchCount;
  53 }
  54