lib/c32to-impl.h

   1 /* Case mapping of a 32-bit wide character.
   2    Copyright (C) 2020-2024 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 2.1 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>, 2023.  */
  18
  19 #include <wchar.h>
  20 #include <wctype.h>
  21
  22 #if GNULIB_defined_mbstate_t
  23 # include "localcharset.h"
  24 # include "streq.h"
  25 #endif
  26
  27 #if GL_CHAR32_T_IS_UNICODE
  28 # include "lc-charset-unicode.h"
  29 #endif
  30
  31 #include "unicase.h"
  32
  33 #if _GL_WCHAR_T_IS_UCS4 && !GNULIB_defined_mbstate_t
  34 _GL_EXTERN_INLINE
  35 #endif
  36 wint_t
  37 FUNC (wint_t wc)
  38 {
  39   /* The char32_t encoding of a multibyte character is defined by the way
  40      mbrtoc32() is defined.  */
  41
  42 #if GNULIB_defined_mbstate_t            /* AIX, IRIX */
  43   /* mbrtoc32() is defined on top of mbtowc() for the non-UTF-8 locales
  44      and directly for the UTF-8 locales.  */
  45   if (wc != WEOF)
  46     {
  47       const char *encoding = locale_charset ();
  48       if (STREQ_OPT (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0, 0))
  49         return UCS_FUNC (wc);
  50       else
  51         return WCHAR_FUNC (wc);
  52     }
  53   else
  54     return wc;
  55
  56 #elif HAVE_WORKING_MBRTOC32             /* glibc, Android */
  57   /* mbrtoc32() is essentially defined by the system libc.  */
  58
  59 # if _GL_WCHAR_T_IS_UCS4
  60   /* The char32_t encoding of a multibyte character is known to be the same as
  61      the wchar_t encoding.  */
  62   return WCHAR_FUNC (wc);
  63 # else
  64   /* The char32_t encoding of a multibyte character is known to be UCS-4,
  65      different from the wchar_t encoding.  */
  66   if (wc != WEOF)
  67     return UCS_FUNC (wc);
  68   else
  69     return wc;
  70 # endif
  71
  72 #elif _GL_SMALL_WCHAR_T                 /* Cygwin, mingw, MSVC */
  73   /* The wchar_t encoding is UTF-16.
  74      The char32_t encoding is UCS-4.  */
  75
  76   if (wc == WEOF || wc == (wchar_t) wc)
  77     /* wc is in the range for the tow* functions.  */
  78     return WCHAR_FUNC (wc);
  79   else
  80     return UCS_FUNC (wc);
  81
  82 #else /* macOS, FreeBSD, NetBSD, OpenBSD, HP-UX, Solaris, Minix, Android */
  83   /* char32_t and wchar_t are equivalent.  */
  84   static_assert (sizeof (char32_t) == sizeof (wchar_t));
  85
  86 # if GL_CHAR32_T_IS_UNICODE && GL_CHAR32_T_VS_WCHAR_T_NEEDS_CONVERSION
  87   return UCS_FUNC (wc);
  88 # else
  89   return WCHAR_FUNC (wc);
  90 # endif
  91 #endif
  92 }