xref: /PHP-8.2/ext/fileinfo/libmagic/strcasestr.c (revision d08451b2)
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 #if defined(LIBC_SCCS) && !defined(lint)
36 __RCSID("$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $");
37 __RCSID("$NetBSD: strncasecmp.c,v 1.2 2007/06/04 18:19:27 christos Exp $");
38 #endif /* LIBC_SCCS and not lint */
39 
40 #include "file.h"
41 
42 #include <inttypes.h>
43 #include <stdint.h>
44 #include <assert.h>
45 #include <ctype.h>
46 #include <string.h>
47 
48 static int
_strncasecmp(const char * s1,const char * s2,size_t n)49 _strncasecmp(const char *s1, const char *s2, size_t n)
50 {
51 	if (n != 0) {
52 		const unsigned char *us1 = (const unsigned char *)s1,
53 				*us2 = (const unsigned char *)s2;
54 
55 		do {
56 			if (tolower(*us1) != tolower(*us2++))
57 				return tolower(*us1) - tolower(*--us2);
58 			if (*us1++ == '\0')
59 				break;
60 		} while (--n != 0);
61 	}
62 	return 0;
63 }
64 
65 /*
66  * Find the first occurrence of find in s, ignore case.
67  */
68 char *
strcasestr(const char * s,const char * find)69 strcasestr(const char *s, const char *find)
70 {
71 	char c, sc;
72 	size_t len;
73 
74 	if ((c = *find++) != 0) {
75 		c = tolower((unsigned char)c);
76 		len = strlen(find);
77 		do {
78 			do {
79 				if ((sc = *s++) == 0)
80 					return (NULL);
81 			} while ((char)tolower((unsigned char)sc) != c);
82 		} while (_strncasecmp(s, find, len) != 0);
83 		s--;
84 	}
85 	return (char *)(intptr_t)(s);
86 }
87