bitstring.h revision 1540 
1/*
2 * Copyright (c) 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Paul Vixie.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	@(#)bitstring.h	8.1 (Berkeley) 7/19/93
37 */
38
39#ifndef _BITSTRING_H_
40#define	_BITSTRING_H_
41
42typedef	unsigned char bitstr_t;
43
44/* internal macros */
45				/* byte of the bitstring bit is in */
46#define	_bit_byte(bit) \
47	((bit) >> 3)
48
49				/* mask for the bit within its byte */
50#define	_bit_mask(bit) \
51	(1 << ((bit)&0x7))
52
53/* external macros */
54				/* bytes in a bitstring of nbits bits */
55#define	bitstr_size(nbits) \
56	((((nbits) - 1) >> 3) + 1)
57
58				/* allocate a bitstring */
59#define	bit_alloc(nbits) \
60	(bitstr_t *)calloc(1, \
61	    (unsigned int)bitstr_size(nbits) * sizeof(bitstr_t))
62
63				/* allocate a bitstring on the stack */
64#define	bit_decl(name, nbits) \
65	(name)[bitstr_size(nbits)]
66
67				/* is bit N of bitstring name set? */
68#define	bit_test(name, bit) \
69	((name)[_bit_byte(bit)] & _bit_mask(bit))
70
71				/* set bit N of bitstring name */
72#define	bit_set(name, bit) \
73	(name)[_bit_byte(bit)] |= _bit_mask(bit)
74
75				/* clear bit N of bitstring name */
76#define	bit_clear(name, bit) \
77	(name)[_bit_byte(bit)] &= ~_bit_mask(bit)
78
79				/* clear bits start ... stop in bitstring */
80#define	bit_nclear(name, start, stop) { \
81	register bitstr_t *_name = name; \
82	register int _start = start, _stop = stop; \
83	register int _startbyte = _bit_byte(_start); \
84	register int _stopbyte = _bit_byte(_stop); \
85	if (_startbyte == _stopbyte) { \
86		_name[_startbyte] &= ((0xff >> (8 - (_start&0x7))) | \
87				      (0xff << ((_stop&0x7) + 1))); \
88	} else { \
89		_name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
90		while (++_startbyte < _stopbyte) \
91			_name[_startbyte] = 0; \
92		_name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
93	} \
94}
95
96				/* set bits start ... stop in bitstring */
97#define	bit_nset(name, start, stop) { \
98	register bitstr_t *_name = name; \
99	register int _start = start, _stop = stop; \
100	register int _startbyte = _bit_byte(_start); \
101	register int _stopbyte = _bit_byte(_stop); \
102	if (_startbyte == _stopbyte) { \
103		_name[_startbyte] |= ((0xff << (_start&0x7)) & \
104				    (0xff >> (7 - (_stop&0x7)))); \
105	} else { \
106		_name[_startbyte] |= 0xff << ((_start)&0x7); \
107		while (++_startbyte < _stopbyte) \
108	    		_name[_startbyte] = 0xff; \
109		_name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
110	} \
111}
112
113				/* find first bit clear in name */
114#define	bit_ffc(name, nbits, value) { \
115	register bitstr_t *_name = name; \
116	register int _byte, _nbits = nbits; \
117	register int _stopbyte = _bit_byte(_nbits), _value = -1; \
118	for (_byte = 0; _byte <= _stopbyte; ++_byte) \
119		if (_name[_byte] != 0xff) { \
120			_value = _byte << 3; \
121			for (_stopbyte = _name[_byte]; (_stopbyte&0x1); \
122			    ++_value, _stopbyte >>= 1); \
123			break; \
124		} \
125	*(value) = _value; \
126}
127
128				/* find first bit set in name */
129#define	bit_ffs(name, nbits, value) { \
130	register bitstr_t *_name = name; \
131	register int _byte, _nbits = nbits; \
132	register int _stopbyte = _bit_byte(_nbits), _value = -1; \
133	for (_byte = 0; _byte <= _stopbyte; ++_byte) \
134		if (_name[_byte]) { \
135			_value = _byte << 3; \
136			for (_stopbyte = _name[_byte]; !(_stopbyte&0x1); \
137			    ++_value, _stopbyte >>= 1); \
138			break; \
139		} \
140	*(value) = _value; \
141}
142
143#endif /* !_BITSTRING_H_ */
144