xref: /illumos-gate/usr/src/common/util/memmove.c (revision 82333da9)
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  */
55 void *
memmove(void * s,const void * s0,size_t n)56 memmove(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