xref: /netbsd-src/common/lib/libc/string/strncasecmp.c (revision 4496cdcb87311f0e271d926254da1a484c4878f4)
1 /*	$NetBSD: strncasecmp.c,v 1.3 2018/08/16 12:03:10 christos Exp $	*/
2 
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. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #if HAVE_NBTOOL_CONFIG_H
33 #include "nbtool_config.h"
34 #endif
35 
36 #include <sys/cdefs.h>
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char sccsid[] = "@(#)strcasecmp.c	8.1 (Berkeley) 6/4/93";
40 #else
41 __RCSID("$NetBSD: strncasecmp.c,v 1.3 2018/08/16 12:03:10 christos Exp $");
42 #endif
43 #endif /* LIBC_SCCS and not lint */
44 
45 #if !defined(_KERNEL) && !defined(_STANDALONE)
46 #include "namespace.h"
47 #include <assert.h>
48 #include <ctype.h>
49 #include <string.h>
50 #ifdef __weak_alias
__weak_alias(strcasecmp,_strcasecmp)51 __weak_alias(strcasecmp,_strcasecmp)
52 __weak_alias(strncasecmp,_strncasecmp)
53 #endif
54 #else
55 #include <lib/libkern/libkern.h>
56 #include <machine/limits.h>
57 #endif
58 
59 int
60 strncasecmp(const char *s1, const char *s2, size_t n)
61 {
62 
63 	_DIAGASSERT(s1 != NULL);
64 	_DIAGASSERT(s2 != NULL);
65 
66 	if (n != 0) {
67 		const unsigned char *us1 = (const unsigned char *)s1,
68 				*us2 = (const unsigned char *)s2;
69 
70 		do {
71 			if (tolower(*us1) != tolower(*us2++))
72 				return (tolower(*us1) - tolower(*--us2));
73 			if (*us1++ == '\0')
74 				break;
75 		} while (--n != 0);
76 	}
77 	return (0);
78 }
79