1/*	$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 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__RCSID("$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $");
38#endif /* LIBC_SCCS and not lint */
39
40#include "namespace.h"
41#include <assert.h>
42#include <ctype.h>
43#include <string.h>
44
45/*
46 * Find the first occurrence of find in s, ignore case.
47 */
48char *
49strcasestr(const char *s, const char *find)
50{
51	char c, sc;
52	size_t len;
53
54	_DIAGASSERT(s != NULL);
55	_DIAGASSERT(find != NULL);
56
57	if ((c = *find++) != 0) {
58		c = tolower((unsigned char)c);
59		len = strlen(find);
60		do {
61			do {
62				if ((sc = *s++) == 0)
63					return (NULL);
64			} while ((char)tolower((unsigned char)sc) != c);
65		} while (strncasecmp(s, find, len) != 0);
66		s--;
67	}
68	return __UNCONST(s);
69}
70