lib/sdk/crt/string/mbstowcs_s.c

   1 /*
   2  * COPYRIGHT:         See COPYING in the top level directory
   3  * PROJECT:           ReactOS CRT
   4  * PURPOSE:           Implementation of mbstowcs_s
   5  * FILE:              lib/sdk/crt/stdlib/mbstowcs_s.c
   6  * PROGRAMMER:        Timo Kreuzer
   7  */
   8
   9 #include <precomp.h>
  10 #include <mbstring.h>
  11
  12 _Success_(return!=EINVAL)
  13 _Check_return_opt_
  14 _CRTIMP
  15 errno_t
  16 __cdecl
  17 mbstowcs_s(
  18    _Out_opt_ size_t *pcchConverted,
  19    _Out_writes_to_opt_(sizeInWords, *pcchConverted) wchar_t *pwcstr,
  20    _In_ size_t sizeInWords,
  21    _In_reads_or_z_(count) const char *pmbstr,
  22    _In_ size_t count)
  23 {
  24     size_t cchMax, cwcWritten;
  25     errno_t retval = 0;
  26
  27     /* Make sure, either we have a target buffer > 0 bytes, or no buffer */
  28     if (!MSVCRT_CHECK_PMT( ((sizeInWords != 0) && (pwcstr != 0)) ||
  29                            ((sizeInWords == 0) && (pwcstr == 0)) ))
  30     {
  31         _set_errno(EINVAL);
  32         return EINVAL;
  33     }
  34
  35     /* Check if we have a return value pointer */
  36     if (pcchConverted)
  37     {
  38         /* Default to 0 bytes written */
  39         *pcchConverted = 0;
  40     }
  41
  42     if (!MSVCRT_CHECK_PMT((count == 0) || (pmbstr != 0)))
  43     {
  44         _set_errno(EINVAL);
  45         return EINVAL;
  46     }
  47
  48     /* Check if there is anything to do */
  49     if ((pwcstr == 0) && (pmbstr == 0))
  50     {
  51         _set_errno(EINVAL);
  52         return EINVAL;
  53     }
  54
  55     /* Check if we have a multibyte string */
  56     if (pmbstr)
  57     {
  58         /* Check if we also have a wchar buffer */
  59         if (pwcstr)
  60         {
  61             /* Calculate the maximum the we can write */
  62             cchMax = (count < sizeInWords) ? count + 1 : sizeInWords;
  63
  64             /* Now do the conversion */
  65             cwcWritten = mbstowcs(pwcstr, pmbstr, cchMax);
  66
  67             /* Check if the buffer was not zero terminated */
  68             if (cwcWritten == cchMax)
  69             {
  70                 /* Check if we reached the max size of the dest buffer */
  71                 if (cwcWritten == sizeInWords)
  72                 {
  73                     /* Does the caller allow this? */
  74                     if (count != _TRUNCATE)
  75                     {
  76                         /* Not allowed, truncate to 0 length */
  77                         pwcstr[0] = L'\0';
  78
  79                         /* Return error */
  80                         _set_errno(ERANGE);
  81                         return ERANGE;
  82                     }
  83
  84                     /* Inform the caller about truncation */
  85                     retval = STRUNCATE;
  86                 }
  87
  88                 /* zero teminate the buffer */
  89                 pwcstr[cwcWritten - 1] = L'\0';
  90             }
  91             else
  92             {
  93                 /* The buffer is zero terminated, count the terminating char */
  94                 cwcWritten++;
  95             }
  96         }
  97         else
  98         {
  99             /* Get the length of the string, plus 0 terminator */
 100             cwcWritten = _mbsnlen((const unsigned char *)pmbstr, count) + 1;
 101         }
 102     }
 103     else
 104     {
 105         cwcWritten = count + 1;
 106     }
 107
 108     /* Check if we have a return value pointer */
 109     if (pcchConverted)
 110     {
 111         /* Default to 0 bytes written */
 112         *pcchConverted = cwcWritten;
 113     }
 114
 115     return retval;
 116 }