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 #ifdef WMEMCHR
  22 # define __wmemchr WMEMCHR
  23 #endif
  24
  25 wchar_t *
  26 __wmemchr (s, c, n)
  27      const wchar_t *s;
  28      wchar_t c;
  29      size_t n;
  30 {
  31   /* For performance reasons unfold the loop four times.  */
  32   while (n >= 4)
  33     {
  34       if (s[0] == c)
  35         return (wchar_t *) s;
  36       if (s[1] == c)
  37         return (wchar_t *) &s[1];
  38       if (s[2] == c)
  39         return (wchar_t *) &s[2];
  40       if (s[3] == c)
  41         return (wchar_t *) &s[3];
  42       s += 4;
  43       n -= 4;
  44     }
  45
  46   if (n > 0)
  47     {
  48       if (*s == c)
  49         return (wchar_t *) s;
  50       ++s;
  51       --n;
  52     }
  53   if (n > 0)
  54     {
  55       if (*s == c)
  56         return (wchar_t *) s;
  57       ++s;
  58       --n;
  59     }
  60   if (n > 0)
  61     if (*s == c)
  62       return (wchar_t *) s;
  63
  64   return NULL;
  65 }
  66 libc_hidden_def (__wmemchr)
  67 weak_alias (__wmemchr, wmemchr)
  68 libc_hidden_weak (wmemchr)