lib/wcrtomb.c

   1 /* Convert wide character to multibyte character.
   2    Copyright (C) 2008-2024 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2008.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 /* Specification.  */
  21 #include <wchar.h>
  22
  23 #include <errno.h>
  24 #include <stdlib.h>
  25
  26
  27 size_t
  28 wcrtomb (char *s, wchar_t wc, mbstate_t *ps)
  29 #undef wcrtomb
  30 {
  31   /* This implementation of wcrtomb supports only stateless encodings.
  32      ps must be in an initial state.  */
  33   if (ps != NULL && !mbsinit (ps))
  34     {
  35       errno = EINVAL;
  36       return (size_t)(-1);
  37     }
  38
  39 #if !HAVE_WCRTOMB                       /* IRIX 6.5 */ \
  40     || WCRTOMB_RETVAL_BUG               /* Solaris 11.3, MSVC */ \
  41     || WCRTOMB_C_LOCALE_BUG             /* Android */
  42   if (s == NULL)
  43     /* We know the NUL wide character corresponds to the NUL character.  */
  44     return 1;
  45   else
  46 #endif
  47     {
  48 #if HAVE_WCRTOMB
  49 # if WCRTOMB_C_LOCALE_BUG               /* Android */
  50       /* Implement consistently with mbrtowc(): through a 1:1 correspondence,
  51          as in ISO-8859-1.  */
  52       if (wc >= 0 && wc <= 0xff)
  53         {
  54           *s = (unsigned char) wc;
  55           return 1;
  56         }
  57       else
  58         {
  59           errno = EILSEQ;
  60           return (size_t)(-1);
  61         }
  62 # else
  63       return wcrtomb (s, wc, ps);
  64 # endif
  65 #else                                   /* IRIX 6.5 */
  66       /* Fallback for platforms that don't have wcrtomb().
  67          Implement on top of wctomb().
  68          This code is not multithread-safe.  */
  69       int ret = wctomb (s, wc);
  70
  71       if (ret >= 0)
  72         return ret;
  73       else
  74         {
  75           errno = EILSEQ;
  76           return (size_t)(-1);
  77         }
  78 #endif
  79     }
  80 }