xref: /freebsd/sys/libkern/strcasecmp.c (revision 6f1af0d7d2af54b339b5212434cd6d4fda628d80)
1 /*-
2  * SPDX-License-Identifier: BSD-4-Clause
3  *
4  * Copyright (c) 1987, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #include <sys/param.h>
38 #include <sys/ctype.h>
39 #include <sys/libkern.h>
40 
41 int
42 strcasecmp(const char *s1, const char *s2)
43 {
44 	const u_char *us1 = (const u_char *)s1, *us2 = (const u_char *)s2;
45 
46 	while (tolower(*us1) == tolower(*us2)) {
47 		if (*us1++ == '\0')
48 			return (0);
49 		us2++;
50 	}
51 	return (tolower(*us1) - tolower(*us2));
52 }
53 
54 int
55 strncasecmp(const char *s1, const char *s2, size_t n)
56 {
57 
58 	if (n != 0) {
59 		const u_char *us1 = (const u_char *)s1;
60 		const u_char *us2 = (const u_char *)s2;
61 
62 		do {
63 			if (tolower(*us1) != tolower(*us2))
64 				return (tolower(*us1) - tolower(*us2));
65 			if (*us1++ == '\0')
66 				break;
67 			us2++;
68 		} while (--n != 0);
69 	}
70 	return (0);
71 }
72