1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26/*
27 * Copyright (c) 2005 Pascal Gloor <pascal.gloor@spale.com>
28 *
29 * Redistribution and use in source and binary forms, with or without
30 * modification, are permitted provided that the following conditions
31 * are met:
32 * 1. Redistributions of source code must retain the above copyright
33 *    notice, this list of conditions and the following disclaimer.
34 * 2. Redistributions in binary form must reproduce the above copyright
35 *    notice, this list of conditions and the following disclaimer in the
36 *    documentation and/or other materials provided with the distribution.
37 * 3. The name of the author may not be used to endorse or promote
38 *    products derived from this software without specific prior written
39 *    permission.
40 *
41 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 */
53
54#include <string.h>
55
56/*
57 * Find the first occurrence of the byte string s in byte string l.
58 */
59
60void *
61memmem(const void *l, size_t l_len, const void *s, size_t s_len)
62{
63	char *cur, *last;
64	const char *cl = (const char *)l;
65	const char *cs = (const char *)s;
66
67	/* we need something to compare */
68	if (l_len == 0 || s_len == 0)
69		return (NULL);
70
71	/* "s" must be smaller or equal to "l" */
72	if (l_len < s_len)
73		return (NULL);
74
75	/* special case where s_len == 1 */
76	if (s_len == 1)
77		return (memchr(l, (int)*cs, l_len));
78
79	/* the last position where its possible to find "s" in "l" */
80	last = (char *)cl + l_len - s_len;
81
82	for (cur = (char *)cl; cur <= last; cur++)
83		if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0)
84			return (cur);
85
86	return (NULL);
87}
88