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/* $OpenBSD: memmem.c,v 1.3 2013/05/30 01:10:45 ajacoutot Exp $ */
/*-
* Copyright (c) 2005 Pascal Gloor <pascal.gloor@spale.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <string.h>
/*
* Find the first occurrence of the byte string s in byte string l.
*/
void *
memmem(const void *l, size_t l_len, const void *s, size_t s_len)
{
const char *cur, *last;
const char *cl = l;
const char *cs = s;
/* a zero length needle should just return the haystack */
if (s_len == 0)
return (void *)cl;
/* "s" must be smaller or equal to "l" */
if (l_len < s_len)
return NULL;
/* special case where s_len == 1 */
if (s_len == 1)
return memchr(l, *cs, l_len);
/* the last position where its possible to find "s" in "l" */
last = cl + l_len - s_len;
for (cur = cl; cur <= last; cur++)
if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0)
return (void *)cur;
return NULL;
}
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