lib/c32tob.c

   1 /* Convert 32-bit wide character to unibyte character.
   2    Copyright (C) 2020 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2020.  */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include <uchar.h>
  23
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <wchar.h>
  27
  28 int
  29 c32tob (wint_t wc)
  30 {
  31 #if HAVE_WORKING_MBRTOC32 && !defined __GLIBC__
  32   /* The char32_t encoding of a multibyte character may be different than its
  33      wchar_t encoding.  */
  34   if (wc != WEOF)
  35     {
  36       mbstate_t state;
  37       char buf[8];
  38
  39       memset (&state, '\0', sizeof (mbstate_t));
  40       if (c32rtomb (buf, wc, &state) == 1)
  41         return (unsigned char) buf[0];
  42     }
  43   return EOF;
  44 #elif _GL_LARGE_CHAR32_T
  45   /* In all known encodings, unibyte characters correspond only to
  46      characters in the BMP.  */
  47   if (wc != WEOF && (wchar_t) wc == wc)
  48     return wctob ((wchar_t) wc);
  49   else
  50     return EOF;
  51 #else
  52   return wctob (wc);
  53 #endif
  54 }