1/* $NetBSD: strstr.c,v 1.2 2007/06/04 18:19:28 christos Exp $ */
2
3/*-
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36#if defined(LIBC_SCCS) && !defined(lint)
37#if 0
38static char sccsid[] = "@(#)strstr.c 8.1 (Berkeley) 6/4/93";
39#else
40__RCSID("$NetBSD: strstr.c,v 1.2 2007/06/04 18:19:28 christos Exp $");
41#endif
42#endif /* LIBC_SCCS and not lint */
43
44#if !defined(_KERNEL) && !defined(_STANDALONE)
45#include <assert.h>
46#include <string.h>
47#else
48#include <sys/param.h>
49#include <lib/libkern/libkern.h>
50#endif
51
52/*
53 * Find the first occurrence of find in s.
54 */
55char *
56strstr(const char *s, const char *find)
57{
58 char c, sc;
59 size_t len;
60
61 _DIAGASSERT(s != NULL);
62 _DIAGASSERT(find != NULL);
63
64 if ((c = *find++) != 0) {
65 len = strlen(find);
66 do {
67 do {
68 if ((sc = *s++) == 0)
69 return (NULL);
70 } while (sc != c);
71 } while (strncmp(s, find, len) != 0);
72 s--;
73 }
74 return __UNCONST(s);
75}
76