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 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $FreeBSD$
33 */
34
35#ifndef _SYS_BITSTRING_H_
36#define	_SYS_BITSTRING_H_
37
38typedef	unsigned char bitstr_t;
39
40/* internal macros */
41				/* byte of the bitstring bit is in */
42#define	_bit_byte(bit) \
43	((bit) >> 3)
44
45				/* mask for the bit within its byte */
46#define	_bit_mask(bit) \
47	(1 << ((bit)&0x7))
48
49/* external macros */
50				/* bytes in a bitstring of nbits bits */
51#define	bitstr_size(nbits) \
52	(((nbits) + 7) >> 3)
53
54				/* allocate a bitstring */
55#define	bit_alloc(nbits) \
56	(bitstr_t *)calloc((size_t)bitstr_size(nbits), sizeof(bitstr_t))
57
58				/* allocate a bitstring on the stack */
59#define	bit_decl(name, nbits) \
60	((name)[bitstr_size(nbits)])
61
62				/* is bit N of bitstring name set? */
63#define	bit_test(name, bit) \
64	((name)[_bit_byte(bit)] & _bit_mask(bit))
65
66				/* set bit N of bitstring name */
67#define	bit_set(name, bit) \
68	((name)[_bit_byte(bit)] |= _bit_mask(bit))
69
70				/* clear bit N of bitstring name */
71#define	bit_clear(name, bit) \
72	((name)[_bit_byte(bit)] &= ~_bit_mask(bit))
73
74				/* clear bits start ... stop in bitstring */
75#define	bit_nclear(name, start, stop) do { \
76	register bitstr_t *_name = (name); \
77	register int _start = (start), _stop = (stop); \
78	register int _startbyte = _bit_byte(_start); \
79	register int _stopbyte = _bit_byte(_stop); \
80	if (_startbyte == _stopbyte) { \
81		_name[_startbyte] &= ((0xff >> (8 - (_start&0x7))) | \
82				      (0xff << ((_stop&0x7) + 1))); \
83	} else { \
84		_name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
85		while (++_startbyte < _stopbyte) \
86			_name[_startbyte] = 0; \
87		_name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
88	} \
89} while (0)
90
91				/* set bits start ... stop in bitstring */
92#define	bit_nset(name, start, stop) do { \
93	register bitstr_t *_name = (name); \
94	register int _start = (start), _stop = (stop); \
95	register int _startbyte = _bit_byte(_start); \
96	register int _stopbyte = _bit_byte(_stop); \
97	if (_startbyte == _stopbyte) { \
98		_name[_startbyte] |= ((0xff << (_start&0x7)) & \
99				    (0xff >> (7 - (_stop&0x7)))); \
100	} else { \
101		_name[_startbyte] |= 0xff << ((_start)&0x7); \
102		while (++_startbyte < _stopbyte) \
103	    		_name[_startbyte] = 0xff; \
104		_name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
105	} \
106} while (0)
107
108				/* find first bit clear in name */
109#define	bit_ffc(name, nbits, value) do { \
110	register bitstr_t *_name = (name); \
111	register int _byte, _nbits = (nbits); \
112	register int _stopbyte = _bit_byte(_nbits - 1), _value = -1; \
113	if (_nbits > 0) \
114		for (_byte = 0; _byte <= _stopbyte; ++_byte) \
115			if (_name[_byte] != 0xff) { \
116				bitstr_t _lb; \
117				_value = _byte << 3; \
118				for (_lb = _name[_byte]; (_lb&0x1); \
119				    ++_value, _lb >>= 1); \
120				break; \
121			} \
122	if (_value >= nbits) \
123		_value = -1; \
124	*(value) = _value; \
125} while (0)
126
127				/* find first bit set in name */
128#define	bit_ffs(name, nbits, value) do { \
129	register bitstr_t *_name = (name); \
130	register int _byte, _nbits = (nbits); \
131	register int _stopbyte = _bit_byte(_nbits - 1), _value = -1; \
132	if (_nbits > 0) \
133		for (_byte = 0; _byte <= _stopbyte; ++_byte) \
134			if (_name[_byte]) { \
135				bitstr_t _lb; \
136				_value = _byte << 3; \
137				for (_lb = _name[_byte]; !(_lb&0x1); \
138				    ++_value, _lb >>= 1); \
139				break; \
140			} \
141	if (_value >= nbits) \
142		_value = -1; \
143	*(value) = _value; \
144} while (0)
145
146#endif /* !_SYS_BITSTRING_H_ */
147