xref: /illumos-gate/usr/src/contrib/ast/src/lib/libast/string/swapget.c (revision b30d193948be5a7794d7ae3ba0ed9c2f72c88e0f)
1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *          Copyright (c) 1985-2011 AT&T Intellectual Property          *
5 *                      and is licensed under the                       *
6 *                 Eclipse Public License, Version 1.0                  *
7 *                    by AT&T Intellectual Property                     *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *          http://www.eclipse.org/org/documents/epl-v10.html           *
11 *         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
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  * get int_n from b according to op
35  */
36 
37 intmax_t
swapget(int op,const void * b,int n)38 swapget(int op, const void* b, int n)
39 {
40 	register unsigned char*	p;
41 	register unsigned char*	d;
42 	intmax_t		v;
43 	unsigned char		tmp[sizeof(intmax_t)];
44 
45 	if (n > sizeof(intmax_t))
46 		n = sizeof(intmax_t);
47 	if (op) swapmem(op, b, d = tmp, n);
48 	else d = (unsigned char*)b;
49 	p = d + n;
50 	v = 0;
51 	while (d < p)
52 	{
53 		v <<= CHAR_BIT;
54 		v |= *d++;
55 	}
56 	return v;
57 }
58