xref: /freebsd/lib/libc/string/strcasecmp.c (revision 9336e0699bda8a301cd2bfa37106b6ec5e32012e)
1 /*
2  * Copyright (c) 1987, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char sccsid[] = "@(#)strcasecmp.c	8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include <strings.h>
37 #include <ctype.h>
38 
39 typedef unsigned char u_char;
40 
41 int
42 strcasecmp(s1, s2)
43 	const char *s1, *s2;
44 {
45 	const u_char
46 			*us1 = (const u_char *)s1,
47 			*us2 = (const u_char *)s2;
48 
49 	while (tolower(*us1) == tolower(*us2++))
50 		if (*us1++ == '\0')
51 			return (0);
52 	return (tolower(*us1) - tolower(*--us2));
53 }
54 
55 int
56 strncasecmp(s1, s2, n)
57 	const char *s1, *s2;
58 	size_t n;
59 {
60 	if (n != 0) {
61 		const u_char
62 				*us1 = (const u_char *)s1,
63 				*us2 = (const u_char *)s2;
64 
65 		do {
66 			if (tolower(*us1) != tolower(*us2++))
67 				return (tolower(*us1) - tolower(*--us2));
68 			if (*us1++ == '\0')
69 				break;
70 		} while (--n != 0);
71 	}
72 	return (0);
73 }
74