wcsmbs/wmemchr.c

   1 /* Copyright (C) 1996, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <wchar.h>
  21
  22 wchar_t *
  23 wmemchr (s, c, n)
  24      register const wchar_t *s;
  25      register wchar_t c;
  26      register size_t n;
  27 {
  28   /* For performance reasons unfold the loop four times.  */
  29   while (n >= 4)
  30     {
  31       if (s[0] == c)
  32         return (wchar_t *) s;
  33       if (s[1] == c)
  34         return (wchar_t *) &s[1];
  35       if (s[2] == c)
  36         return (wchar_t *) &s[2];
  37       if (s[3] == c)
  38         return (wchar_t *) &s[3];
  39       s += 4;
  40       n -= 4;
  41     }
  42
  43   if (n > 0)
  44     {
  45       if (*s == c)
  46         return (wchar_t *) s;
  47       ++s;
  48       --n;
  49     }
  50   if (n > 0)
  51     {
  52       if (*s == c)
  53         return (wchar_t *) s;
  54       ++s;
  55       --n;
  56     }
  57   if (n > 0)
  58     if (*s == c)
  59       return (wchar_t *) s;
  60
  61   return NULL;
  62 }