1 e80a23a1 2021-07-14 op /*	$OpenBSD: strcasestr.c,v 1.4 2015/08/31 02:53:57 guenther Exp $	*/
 2 e80a23a1 2021-07-14 op /*	$NetBSD: strcasestr.c,v 1.2 2005/02/09 21:35:47 kleink Exp $	*/
 3 e80a23a1 2021-07-14 op 
 4 e80a23a1 2021-07-14 op /*-
 5 e80a23a1 2021-07-14 op  * Copyright (c) 1990, 1993
 6 e80a23a1 2021-07-14 op  *	The Regents of the University of California.  All rights reserved.
 7 e80a23a1 2021-07-14 op  *
 8 e80a23a1 2021-07-14 op  * This code is derived from software contributed to Berkeley by
 9 e80a23a1 2021-07-14 op  * Chris Torek.
10 e80a23a1 2021-07-14 op  *
11 e80a23a1 2021-07-14 op  * Redistribution and use in source and binary forms, with or without
12 e80a23a1 2021-07-14 op  * modification, are permitted provided that the following conditions
13 e80a23a1 2021-07-14 op  * are met:
14 e80a23a1 2021-07-14 op  * 1. Redistributions of source code must retain the above copyright
15 e80a23a1 2021-07-14 op  *    notice, this list of conditions and the following disclaimer.
16 e80a23a1 2021-07-14 op  * 2. Redistributions in binary form must reproduce the above copyright
17 e80a23a1 2021-07-14 op  *    notice, this list of conditions and the following disclaimer in the
18 e80a23a1 2021-07-14 op  *    documentation and/or other materials provided with the distribution.
19 e80a23a1 2021-07-14 op  * 3. Neither the name of the University nor the names of its contributors
20 e80a23a1 2021-07-14 op  *    may be used to endorse or promote products derived from this software
21 e80a23a1 2021-07-14 op  *    without specific prior written permission.
22 e80a23a1 2021-07-14 op  *
23 e80a23a1 2021-07-14 op  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 e80a23a1 2021-07-14 op  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 e80a23a1 2021-07-14 op  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 e80a23a1 2021-07-14 op  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 e80a23a1 2021-07-14 op  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 e80a23a1 2021-07-14 op  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 e80a23a1 2021-07-14 op  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 e80a23a1 2021-07-14 op  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 e80a23a1 2021-07-14 op  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 e80a23a1 2021-07-14 op  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 e80a23a1 2021-07-14 op  * SUCH DAMAGE.
34 e80a23a1 2021-07-14 op  */
35 e80a23a1 2021-07-14 op 
36 e80a23a1 2021-07-14 op #include <ctype.h>
37 e80a23a1 2021-07-14 op #include <string.h>
38 e80a23a1 2021-07-14 op 
39 e80a23a1 2021-07-14 op /*
40 e80a23a1 2021-07-14 op  * Find the first occurrence of find in s, ignore case.
41 e80a23a1 2021-07-14 op  */
42 e80a23a1 2021-07-14 op char *
43 e80a23a1 2021-07-14 op strcasestr(const char *s, const char *find)
44 e80a23a1 2021-07-14 op {
45 e80a23a1 2021-07-14 op 	char c, sc;
46 e80a23a1 2021-07-14 op 	size_t len;
47 e80a23a1 2021-07-14 op 
48 e80a23a1 2021-07-14 op 	if ((c = *find++) != 0) {
49 e80a23a1 2021-07-14 op 		c = (char)tolower((unsigned char)c);
50 e80a23a1 2021-07-14 op 		len = strlen(find);
51 e80a23a1 2021-07-14 op 		do {
52 e80a23a1 2021-07-14 op 			do {
53 e80a23a1 2021-07-14 op 				if ((sc = *s++) == 0)
54 e80a23a1 2021-07-14 op 					return (NULL);
55 e80a23a1 2021-07-14 op 			} while ((char)tolower((unsigned char)sc) != c);
56 e80a23a1 2021-07-14 op 		} while (strncasecmp(s, find, len) != 0);
57 e80a23a1 2021-07-14 op 		s--;
58 e80a23a1 2021-07-14 op 	}
59 e80a23a1 2021-07-14 op 	return ((char *)s);
60 e80a23a1 2021-07-14 op }