glibc/wcsmbs/wmemchr.c

63 lines
1.6 KiB
C

/* Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <wchar.h>
wchar_t *
wmemchr (s, c, n)
register const wchar_t *s;
register wchar_t c;
register size_t n;
{
/* For performance reasons unfold the loop four times. */
while (n >= 4)
{
if (s[0] == c)
return (wchar_t *) s;
if (s[1] == c)
return (wchar_t *) &s[1];
if (s[2] == c)
return (wchar_t *) &s[2];
if (s[3] == c)
return (wchar_t *) &s[3];
s += 4;
n -= 4;
}
if (n > 0)
{
if (*s == c)
return (wchar_t *) s;
++s;
--n;
}
if (n > 0)
{
if (*s == c)
return (wchar_t *) s;
++s;
--n;
}
if (n > 0)
if (*s == c)
return (wchar_t *) s;
return NULL;
}