wcsmbs/wmemchr.c

   1 /* Copyright (C) 1996-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.org>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <wchar.h>
  20
  21 wchar_t *
  22 wmemchr (s, c, n)
  23      const wchar_t *s;
  24      wchar_t c;
  25      size_t n;
  26 {
  27   /* For performance reasons unfold the loop four times.  */
  28   while (n >= 4)
  29     {
  30       if (s[0] == c)
  31         return (wchar_t *) s;
  32       if (s[1] == c)
  33         return (wchar_t *) &s[1];
  34       if (s[2] == c)
  35         return (wchar_t *) &s[2];
  36       if (s[3] == c)
  37         return (wchar_t *) &s[3];
  38       s += 4;
  39       n -= 4;
  40     }
  41
  42   if (n > 0)
  43     {
  44       if (*s == c)
  45         return (wchar_t *) s;
  46       ++s;
  47       --n;
  48     }
  49   if (n > 0)
  50     {
  51       if (*s == c)
  52         return (wchar_t *) s;
  53       ++s;
  54       --n;
  55     }
  56   if (n > 0)
  57     if (*s == c)
  58       return (wchar_t *) s;
  59
  60   return NULL;
  61 }
  62 libc_hidden_def (wmemchr)