bitops.h revision 266692 
1/*
2 * Copyright (c) 1998-2001 Proofpoint, Inc. and its suppliers.
3 *	All rights reserved.
4 * Copyright (c) 1983, 1995-1997 Eric P. Allman.  All rights reserved.
5 * Copyright (c) 1988, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * By using this file, you agree to the terms and conditions set
9 * forth in the LICENSE file which can be found at the top level of
10 * the sendmail distribution.
11 *
12 *
13 *	$Id: bitops.h,v 1.3 2013-11-22 20:51:31 ca Exp $
14 */
15
16#ifndef	SM_BITOPS_H
17# define SM_BITOPS_H
18
19/*
20**  Data structure for bit maps.
21**
22**	Each bit in this map can be referenced by an ascii character.
23**	This is 256 possible bits, or 32 8-bit bytes.
24*/
25
26# define BITMAPBITS	256	/* number of bits in a bit map */
27# define BYTEBITS	8	/* number of bits in a byte */
28# define BITMAPBYTES	(BITMAPBITS / BYTEBITS)	/* number of bytes in bit map */
29# define BITMAPMAX	((BITMAPBYTES / sizeof (int)) - 1)
30
31/* internal macros */
32
33/* make sure this index never leaves the allowed range: 0 to BITMAPMAX */
34# define _BITWORD(bit)	(((unsigned char)(bit) / (BYTEBITS * sizeof (int))) & BITMAPMAX)
35# define _BITBIT(bit)	((unsigned int)1 << ((unsigned char)(bit) % (BYTEBITS * sizeof (int))))
36
37typedef unsigned int	BITMAP256[BITMAPBYTES / sizeof (int)];
38
39/* properly case and truncate bit */
40# define bitidx(bit)		((unsigned int) (bit) & 0xff)
41
42/* test bit number N */
43# define bitnset(bit, map)	((map)[_BITWORD(bit)] & _BITBIT(bit))
44
45/* set bit number N */
46# define setbitn(bit, map)	(map)[_BITWORD(bit)] |= _BITBIT(bit)
47
48/* clear bit number N */
49# define clrbitn(bit, map)	(map)[_BITWORD(bit)] &= ~_BITBIT(bit)
50
51/* clear an entire bit map */
52# define clrbitmap(map)		memset((char *) map, '\0', BITMAPBYTES)
53
54/* bit hacking */
55# define bitset(bit, word)	(((word) & (bit)) != 0)
56
57#endif /* ! SM_BITOPS_H */
58