xref: /illumos-gate/usr/src/lib/libmail/common/casncmp.c (revision 1da57d551424de5a9d469760be7c4b4d4f10a755)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  *  NAME
32  *	casncmp - compare strings ignoring case
33  *
34  *  SYNOPSIS
35  *	int casncmp(char *s1, char *s2, ssize_t n)
36  *
37  *  DESCRIPTION
38  *	Compare two strings ignoring case differences.
39  *	Stop after n bytes or the trailing NUL.
40  */
41 
42 #include "libmail.h"
43 #include <ctype.h>
44 #include <sys/types.h>
45 
46 int
casncmp(char * s1,char * s2,ssize_t n)47 casncmp(char *s1, char *s2, ssize_t n)
48 {
49 	if (s1 == s2)
50 		return (0);
51 	while ((--n >= 0) && (tolower(*s1) == tolower(*s2))) {
52 		s2++;
53 		if (*s1++ == '\0')
54 			return (0);
55 	}
56 	return ((n < 0)? 0: (*s1 - *s2));
57 }
58