lib/mbscspn.c

   1 /* Searching a string for a character among a given set of characters.
   2    Copyright (C) 1999, 2002, 2006-2021 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2007.
   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 <string.h>
  22
  23 #include "mbuiter.h"
  24
  25 /* Find the first occurrence in the character string STRING of any character
  26    in the character string ACCEPT.  Return the number of bytes from the
  27    beginning of the string to this occurrence, or to the end of the string
  28    if none exists.  */
  29 size_t
  30 mbscspn (const char *string, const char *accept)
  31 {
  32   /* Optimize two cases.  */
  33   if (accept[0] == '\0')
  34     return strlen (string);
  35   if (accept[1] == '\0')
  36     {
  37       const char *ptr = mbschr (string, accept[0]);
  38       return (ptr != NULL ? ptr - string : strlen (string));
  39     }
  40   /* General case.  */
  41   if (MB_CUR_MAX > 1)
  42     {
  43       mbui_iterator_t iter;
  44
  45       for (mbui_init (iter, string); mbui_avail (iter); mbui_advance (iter))
  46         {
  47           if (mb_len (mbui_cur (iter)) == 1)
  48             {
  49               if (mbschr (accept, * mbui_cur_ptr (iter)))
  50                 goto found;
  51             }
  52           else
  53             {
  54               mbui_iterator_t aiter;
  55
  56               for (mbui_init (aiter, accept);
  57                    mbui_avail (aiter);
  58                    mbui_advance (aiter))
  59                 if (mb_equal (mbui_cur (aiter), mbui_cur (iter)))
  60                   goto found;
  61             }
  62         }
  63      found:
  64       return mbui_cur_ptr (iter) - string;
  65     }
  66   else
  67     return strcspn (string, accept);
  68 }