xref: /titanic_52/usr/src/common/util/memcmp.c (revision c2580b931007758eab8cb5ae8726ebe1588e259b)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*	Copyright (c) 1988 AT&T	*/
30 /*	  All Rights Reserved  	*/
31 
32 
33 #if !defined(_KMDB) && !defined(_BOOT) && !defined(_KERNEL)
34 
35 #pragma weak memcmp = _memcmp
36 
37 #include "synonyms.h"
38 #endif /* !_KMDB && !_BOOT && !_KERNEL */
39 
40 #include <sys/types.h>
41 #if defined(_KERNEL)
42 #include <sys/systm.h>
43 #else
44 #include <string.h>
45 #include <stddef.h>
46 #endif
47 
48 /*
49  * Compare n bytes:  s1>s2: >0  s1==s2: 0  s1<s2: <0
50  */
51 int
52 memcmp(const void *s1, const void *s2, size_t n)
53 {
54 	if (s1 != s2 && n != 0) {
55 		const unsigned char *ps1 = s1;
56 		const unsigned char *ps2 = s2;
57 
58 		do {
59 			if (*ps1++ != *ps2++)
60 				return (ps1[-1] - ps2[-1]);
61 		} while (--n != 0);
62 	}
63 
64 	return (0);
65 }
66