xref: /titanic_44/usr/src/lib/libast/common/comp/memmove.c (revision 023e71de9e5670cebc23dd51162833661d3d2d3b)
1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *          Copyright (c) 1985-2009 AT&T Intellectual Property          *
5 *                      and is licensed under the                       *
6 *                  Common Public License, Version 1.0                  *
7 *                    by AT&T Intellectual Property                     *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12 *                                                                      *
13 *              Information and Software Systems Research               *
14 *                            AT&T Research                             *
15 *                           Florham Park NJ                            *
16 *                                                                      *
17 *                 Glenn Fowler <gsf@research.att.com>                  *
18 *                  David Korn <dgk@research.att.com>                   *
19 *                   Phong Vo <kpv@research.att.com>                    *
20 *                                                                      *
21 ***********************************************************************/
22 #pragma prototyped
23 
24 #include <ast.h>
25 
26 #if _lib_memmove
27 
28 NoN(memmove)
29 
30 #else
31 
32 void*
33 memmove(void* to, const void* from, register size_t n)
34 {
35 	register char*	out = (char*)to;
36 	register char*	in = (char*)from;
37 
38 	if (n <= 0)	/* works if size_t is signed or not */
39 		;
40 	else if (in + n <= out || out + n <= in)
41 		return(memcpy(to, from, n));	/* hope it's fast*/
42 	else if (out < in)
43 		do *out++ = *in++; while (--n > 0);
44 	else
45 	{
46 		out += n;
47 		in += n;
48 		do *--out = *--in; while(--n > 0);
49 	}
50 	return(to);
51 }
52 
53 #endif
54