FreeBSD/Linux Kernel Cross Reference
sys/sys/bitstring.h
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: src/sys/sys/bitstring.h,v 1.5 2005/01/07 02:29:23 imp Exp $
33 */
34
35 #ifndef _SYS_BITSTRING_H_
36 #define _SYS_BITSTRING_H_
37
38 typedef 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
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