67 lines
2.3 KiB
C
67 lines
2.3 KiB
C
/* $OpenBSD: memmem.c,v 1.4 2015/08/31 02:53:57 guenther 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>
|
|
|
|
#include "../util.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;
|
|
}
|