gnulib/import/mbrtowc.c

   1 /* Convert multibyte character to wide character.
   2    Copyright (C) 1999-2002, 2005-2020 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2008.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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 General Public License for more details.
  14
  15    You should have received a copy of the GNU 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 #if GNULIB_defined_mbstate_t
  24 /* Implement mbrtowc() on top of mbtowc() for the non-UTF-8 locales
  25    and directly for the UTF-8 locales.  */
  26
  27 # include <errno.h>
  28 # include <stdint.h>
  29 # include <stdlib.h>
  30
  31 # if defined _WIN32 && !defined __CYGWIN__
  32
  33 #  define WIN32_LEAN_AND_MEAN  /* avoid including junk */
  34 #  include <windows.h>
  35
  36 # elif HAVE_PTHREAD_API
  37
  38 #  include <pthread.h>
  39 #  if HAVE_THREADS_H && HAVE_WEAK_SYMBOLS
  40 #   include <threads.h>
  41 #   pragma weak thrd_exit
  42 #   define c11_threads_in_use() (thrd_exit != NULL)
  43 #  else
  44 #   define c11_threads_in_use() 0
  45 #  endif
  46
  47 # elif HAVE_THREADS_H
  48
  49 #  include <threads.h>
  50
  51 # endif
  52
  53 # include "verify.h"
  54 # include "lc-charset-dispatch.h"
  55 # include "mbtowc-lock.h"
  56
  57 # ifndef FALLTHROUGH
  58 #  if __GNUC__ < 7
  59 #   define FALLTHROUGH ((void) 0)
  60 #  else
  61 #   define FALLTHROUGH __attribute__ ((__fallthrough__))
  62 #  endif
  63 # endif
  64
  65 verify (sizeof (mbstate_t) >= 4);
  66 static char internal_state[4];
  67
  68 size_t
  69 mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
  70 {
  71 # define FITS_IN_CHAR_TYPE(wc)  ((wc) <= WCHAR_MAX)
  72 # include "mbrtowc-impl.h"
  73 }
  74
  75 #else
  76 /* Override the system's mbrtowc() function.  */
  77
  78 # if MBRTOWC_IN_C_LOCALE_MAYBE_EILSEQ
  79 #  include "hard-locale.h"
  80 #  include <locale.h>
  81 # endif
  82
  83 # undef mbrtowc
  84
  85 size_t
  86 rpl_mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
  87 {
  88   size_t ret;
  89   wchar_t wc;
  90
  91 # if MBRTOWC_NULL_ARG2_BUG || MBRTOWC_RETVAL_BUG || MBRTOWC_EMPTY_INPUT_BUG
  92   if (s == NULL)
  93     {
  94       pwc = NULL;
  95       s = "";
  96       n = 1;
  97     }
  98 # endif
  99
 100 # if MBRTOWC_EMPTY_INPUT_BUG
 101   if (n == 0)
 102     return (size_t) -2;
 103 # endif
 104
 105   if (! pwc)
 106     pwc = &wc;
 107
 108 # if MBRTOWC_RETVAL_BUG
 109   {
 110     static mbstate_t internal_state;
 111
 112     /* Override mbrtowc's internal state.  We cannot call mbsinit() on the
 113        hidden internal state, but we can call it on our variable.  */
 114     if (ps == NULL)
 115       ps = &internal_state;
 116
 117     if (!mbsinit (ps))
 118       {
 119         /* Parse the rest of the multibyte character byte for byte.  */
 120         size_t count = 0;
 121         for (; n > 0; s++, n--)
 122           {
 123             ret = mbrtowc (&wc, s, 1, ps);
 124
 125             if (ret == (size_t)(-1))
 126               return (size_t)(-1);
 127             count++;
 128             if (ret != (size_t)(-2))
 129               {
 130                 /* The multibyte character has been completed.  */
 131                 *pwc = wc;
 132                 return (wc == 0 ? 0 : count);
 133               }
 134           }
 135         return (size_t)(-2);
 136       }
 137   }
 138 # endif
 139
 140 # if MBRTOWC_STORES_INCOMPLETE_BUG
 141   ret = mbrtowc (&wc, s, n, ps);
 142   if (ret < (size_t) -2 && pwc != NULL)
 143     *pwc = wc;
 144 # else
 145   ret = mbrtowc (pwc, s, n, ps);
 146 # endif
 147
 148 # if MBRTOWC_NUL_RETVAL_BUG
 149   if (ret < (size_t) -2 && !*pwc)
 150     return 0;
 151 # endif
 152
 153 # if MBRTOWC_IN_C_LOCALE_MAYBE_EILSEQ
 154   if ((size_t) -2 <= ret && n != 0 && ! hard_locale (LC_CTYPE))
 155     {
 156       unsigned char uc = *s;
 157       *pwc = uc;
 158       return 1;
 159     }
 160 # endif
 161
 162   return ret;
 163 }
 164
 165 #endif