1  /* Convert 32-bit wide character to unibyte character.
       2     Copyright (C) 2020-2023 Free Software Foundation, Inc.
       3  
       4     This file is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU Lesser General Public License as
       6     published by the Free Software Foundation, either version 3 of the
       7     License, or (at your option) any later version.
       8  
       9     This file 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 Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser 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  #define IN_C32TOB
      22  /* Specification.  */
      23  #include <uchar.h>
      24  
      25  #include <stdio.h>
      26  #include <string.h>
      27  #include <wchar.h>
      28  
      29  #if GL_CHAR32_T_IS_UNICODE
      30  # include "lc-charset-unicode.h"
      31  #endif
      32  
      33  #if _GL_WCHAR_T_IS_UCS4
      34  _GL_EXTERN_INLINE
      35  #endif
      36  int
      37  c32tob (wint_t wc)
      38  {
      39  #if HAVE_WORKING_MBRTOC32 && !_GL_WCHAR_T_IS_UCS4
      40    /* The char32_t encoding of a multibyte character may be different than its
      41       wchar_t encoding.  */
      42    if (wc != WEOF)
      43      {
      44        mbstate_t state;
      45        char buf[8];
      46  
      47        mbszero (&state);
      48        if (c32rtomb (buf, wc, &state) == 1)
      49          return (unsigned char) buf[0];
      50      }
      51    return EOF;
      52  #elif _GL_SMALL_WCHAR_T
      53    /* In all known encodings, unibyte characters correspond only to
      54       characters in the BMP.  */
      55    if (wc != WEOF && (wchar_t) wc == wc)
      56      return wctob ((wchar_t) wc);
      57    else
      58      return EOF;
      59  #else
      60  # if GL_CHAR32_T_IS_UNICODE && GL_CHAR32_T_VS_WCHAR_T_NEEDS_CONVERSION
      61    if (wc != 0)
      62      {
      63        wc = unicode_to_locale_encoding (wc);
      64        if (wc == 0)
      65          return EOF;
      66      }
      67  # endif
      68    return wctob (wc);
      69  #endif
      70  }