memmove.c revision 82333da930cddbdbdfe38acf480e9c35fb875d2d
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 (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26/*	Copyright (c) 1988 AT&T	*/
27/*	  All Rights Reserved  	*/
28
29#if !defined(_KMDB) && !defined(_KERNEL)
30
31#include "lint.h"
32
33#endif /* !_KMDB && !_KERNEL */
34
35/*
36 * The SunStudio compiler may generate calls to _memmove; So we
37 * need to make sure that the correct symbol exists for these calls.
38 */
39#pragma weak _memmove = memmove
40
41#include <sys/types.h>
42
43#if defined(_KERNEL)
44#include <sys/systm.h>
45#else
46#include <string.h>
47#include <memory.h>
48#endif
49
50/*
51 * Copy s0 to s, always copy n bytes.
52 * Return s
53 * Copying between objects that overlap will take place correctly
54 */
55void *
56memmove(void *s, const void *s0, size_t n)
57{
58	if (n != 0) {
59		char *s1 = s;
60		const char *s2 = s0;
61
62		if (s1 <= s2) {
63			do {
64				*s1++ = *s2++;
65			} while (--n != 0);
66		} else {
67			s2 += n;
68			s1 += n;
69			do {
70				*--s1 = *--s2;
71			} while (--n != 0);
72		}
73	}
74	return (s);
75}
76