1/***********************************************************************
2*                                                                      *
3*               This software is part of the ast package               *
4*          Copyright (c) 1985-2010 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 * Glenn Fowler
25 * AT&T Research
26 *
27 * internal representation conversion support
28 */
29
30#include <ast.h>
31#include <swap.h>
32
33/*
34 * return the swap operation for external to internal conversion
35 * if size<0 then (-size) used and (-size==4)&&(op==3) => op=7
36 * this is a workaround for 4 byte magic predicting 8 byte swap
37 */
38
39int
40swapop(const void* internal, const void* external, int size)
41{
42	register int	op;
43	register int	z;
44	char		tmp[sizeof(intmax_t)];
45
46	if ((z = size) < 0)
47		z = -z;
48	if (z <= 1)
49		return 0;
50	if (z <= sizeof(intmax_t))
51		for (op = 0; op < z; op++)
52			if (!memcmp(internal, swapmem(op, external, tmp, z), z))
53			{
54				if (size < 0 && z == 4 && op == 3)
55					op = 7;
56				return op;
57			}
58	return -1;
59}
60