lib/wcscspn-impl.h

   1 /* Search a wide string for any of a set of wide characters.
   2    Copyright (C) 1999, 2011-2024 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 1999.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation, either version 3 of the
   8    License, or (at your option) any later version.
   9
  10    This file 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 Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 size_t
  19 wcscspn (const wchar_t *wcs, const wchar_t *reject)
  20 {
  21   /* Optimize two cases.  */
  22   if (reject[0] == (wchar_t)'\0')
  23     return wcslen (wcs);
  24
  25   if (reject[1] == (wchar_t)'\0')
  26     {
  27       wchar_t wc = reject[0];
  28       const wchar_t *ptr = wcs;
  29       for (; *ptr != (wchar_t)'\0'; ptr++)
  30         {
  31           if (*ptr == wc)
  32             break;
  33         }
  34       return ptr - wcs;
  35     }
  36
  37   /* General case.  */
  38   {
  39     const wchar_t *ptr = wcs;
  40     for (; *ptr != (wchar_t)'\0'; ptr++)
  41       {
  42         if (wcschr (reject, *ptr))
  43           break;
  44       }
  45     return ptr - wcs;
  46   }
  47 }