xref: /freebsd/lib/libc/string/strcasestr.c (revision 734e82fe33aa764367791a7d603b383996c6b40b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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  * Copyright (c) 2011 The FreeBSD Foundation
11  *
12  * Portions of this software were developed by David Chisnall
13  * under sponsorship from the FreeBSD Foundation.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  */
39 
40 #include <sys/cdefs.h>
41 #include <ctype.h>
42 #include <string.h>
43 #include "xlocale_private.h"
44 
45 /*
46  * Find the first occurrence of find in s, ignore case.
47  */
48 char *
49 strcasestr_l(const char *s, const char *find, locale_t locale)
50 {
51 	char c, sc;
52 	size_t len;
53 	FIX_LOCALE(locale);
54 
55 	if ((c = *find++) != 0) {
56 		c = tolower_l((unsigned char)c, locale);
57 		len = strlen(find);
58 		do {
59 			do {
60 				if ((sc = *s++) == 0)
61 					return (NULL);
62 			} while ((char)tolower_l((unsigned char)sc, locale) != c);
63 		} while (strncasecmp_l(s, find, len, locale) != 0);
64 		s--;
65 	}
66 	return ((char *)s);
67 }
68 char *
69 strcasestr(const char *s, const char *find)
70 {
71 	return strcasestr_l(s, find, __get_locale());
72 }
73