OpenSolaris_b135/common/util/memcmp.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*	Copyright (c) 1988 AT&T	*/
/*	  All Rights Reserved  	*/

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#if !defined(_KMDB) && !defined(_BOOT) && !defined(_KERNEL)

#pragma weak _memcmp = memcmp

#include "lint.h"
#endif /* !_KMDB && !_BOOT && !_KERNEL */

#include <sys/types.h>
#if defined(_KERNEL)
#include <sys/systm.h>
#else
#include <string.h>
#include <stddef.h>
#endif

/*
 * Compare n bytes:  s1>s2: >0  s1==s2: 0  s1<s2: <0
 */
int
memcmp(const void *s1, const void *s2, size_t n)
{
	if (s1 != s2 && n != 0) {
		const unsigned char *ps1 = s1;
		const unsigned char *ps2 = s2;

		do {
			if (*ps1++ != *ps2++)
				return (ps1[-1] - ps2[-1]);
		} while (--n != 0);
	}

	return (0);
}