FreeBSD/Linux Kernel Cross Reference
sys/sys/bitstring.h
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Paul Vixie.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * Copyright (c) 2014 Spectra Logic Corporation
35 * All rights reserved.
36 *
37 * Redistribution and use in source and binary forms, with or without
38 * modification, are permitted provided that the following conditions
39 * are met:
40 * 1. Redistributions of source code must retain the above copyright
41 * notice, this list of conditions, and the following disclaimer,
42 * without modification.
43 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
44 * substantially similar to the "NO WARRANTY" disclaimer below
45 * ("Disclaimer") and any redistribution must be conditioned upon
46 * including a substantially similar Disclaimer requirement for further
47 * binary redistribution.
48 *
49 * NO WARRANTY
50 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
51 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
52 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
53 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
54 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
58 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
59 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
60 * POSSIBILITY OF SUCH DAMAGES.
61 *
62 * $FreeBSD: releng/12.0/sys/sys/bitstring.h 326023 2017-11-20 19:43:44Z pfg $
63 */
64 #ifndef _SYS_BITSTRING_H_
65 #define _SYS_BITSTRING_H_
66
67 #ifdef _KERNEL
68 #include <sys/libkern.h>
69 #include <sys/malloc.h>
70 #endif
71
72 #include <sys/types.h>
73
74 typedef unsigned long bitstr_t;
75
76 /*---------------------- Private Implementation Details ----------------------*/
77 #define _BITSTR_MASK (~0UL)
78 #define _BITSTR_BITS (sizeof(bitstr_t) * 8)
79
80 #ifdef roundup2
81 #define _bit_roundup2 roundup2
82 #else
83 #define _bit_roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
84 #endif
85
86 /* bitstr_t in bit string containing the bit. */
87 static inline int
88 _bit_idx(int _bit)
89 {
90 return (_bit / _BITSTR_BITS);
91 }
92
93 /* bit number within bitstr_t at _bit_idx(_bit). */
94 static inline int
95 _bit_offset(int _bit)
96 {
97 return (_bit % _BITSTR_BITS);
98 }
99
100 /* Mask for the bit within its long. */
101 static inline bitstr_t
102 _bit_mask(int _bit)
103 {
104 return (1UL << _bit_offset(_bit));
105 }
106
107 static inline bitstr_t
108 _bit_make_mask(int _start, int _stop)
109 {
110 return ((_BITSTR_MASK << _bit_offset(_start)) &
111 (_BITSTR_MASK >> (_BITSTR_BITS - _bit_offset(_stop) - 1)));
112 }
113
114 /*----------------------------- Public Interface -----------------------------*/
115 /* Number of bytes allocated for a bit string of nbits bits */
116 #define bitstr_size(_nbits) (_bit_roundup2(_nbits, _BITSTR_BITS) / 8)
117
118 /* Allocate a bit string initialized with no bits set. */
119 #ifdef _KERNEL
120 static inline bitstr_t *
121 bit_alloc(int _nbits, struct malloc_type *type, int flags)
122 {
123 return ((bitstr_t *)malloc(bitstr_size(_nbits), type, flags | M_ZERO));
124 }
125 #else
126 static inline bitstr_t *
127 bit_alloc(int _nbits)
128 {
129 return ((bitstr_t *)calloc(bitstr_size(_nbits), 1));
130 }
131 #endif
132
133 /* Allocate a bit string on the stack */
134 #define bit_decl(name, nbits) \
135 ((name)[bitstr_size(nbits) / sizeof(bitstr_t)])
136
137 /* Is bit N of bit string set? */
138 static inline int
139 bit_test(const bitstr_t *_bitstr, int _bit)
140 {
141 return ((_bitstr[_bit_idx(_bit)] & _bit_mask(_bit)) != 0);
142 }
143
144 /* Set bit N of bit string. */
145 static inline void
146 bit_set(bitstr_t *_bitstr, int _bit)
147 {
148 _bitstr[_bit_idx(_bit)] |= _bit_mask(_bit);
149 }
150
151 /* clear bit N of bit string name */
152 static inline void
153 bit_clear(bitstr_t *_bitstr, int _bit)
154 {
155 _bitstr[_bit_idx(_bit)] &= ~_bit_mask(_bit);
156 }
157
158 /* Set bits start ... stop inclusive in bit string. */
159 static inline void
160 bit_nset(bitstr_t *_bitstr, int _start, int _stop)
161 {
162 bitstr_t *_stopbitstr;
163
164 _stopbitstr = _bitstr + _bit_idx(_stop);
165 _bitstr += _bit_idx(_start);
166
167 if (_bitstr == _stopbitstr) {
168 *_bitstr |= _bit_make_mask(_start, _stop);
169 } else {
170 *_bitstr |= _bit_make_mask(_start, _BITSTR_BITS - 1);
171 while (++_bitstr < _stopbitstr)
172 *_bitstr = _BITSTR_MASK;
173 *_stopbitstr |= _bit_make_mask(0, _stop);
174 }
175 }
176
177 /* Clear bits start ... stop inclusive in bit string. */
178 static inline void
179 bit_nclear(bitstr_t *_bitstr, int _start, int _stop)
180 {
181 bitstr_t *_stopbitstr;
182
183 _stopbitstr = _bitstr + _bit_idx(_stop);
184 _bitstr += _bit_idx(_start);
185
186 if (_bitstr == _stopbitstr) {
187 *_bitstr &= ~_bit_make_mask(_start, _stop);
188 } else {
189 *_bitstr &= ~_bit_make_mask(_start, _BITSTR_BITS - 1);
190 while (++_bitstr < _stopbitstr)
191 *_bitstr = 0;
192 *_stopbitstr &= ~_bit_make_mask(0, _stop);
193 }
194 }
195
196 /* Find the first bit set in bit string at or after bit start. */
197 static inline void
198 bit_ffs_at(bitstr_t *_bitstr, int _start, int _nbits, int *_result)
199 {
200 bitstr_t *_curbitstr;
201 bitstr_t *_stopbitstr;
202 bitstr_t _test;
203 int _value, _offset;
204
205 if (_nbits > 0) {
206 _curbitstr = _bitstr + _bit_idx(_start);
207 _stopbitstr = _bitstr + _bit_idx(_nbits - 1);
208
209 _test = *_curbitstr;
210 if (_bit_offset(_start) != 0)
211 _test &= _bit_make_mask(_start, _BITSTR_BITS - 1);
212 while (_test == 0 && _curbitstr < _stopbitstr)
213 _test = *(++_curbitstr);
214
215 _offset = ffsl(_test);
216 _value = ((_curbitstr - _bitstr) * _BITSTR_BITS) + _offset - 1;
217 if (_offset == 0 || _value >= _nbits)
218 _value = -1;
219 } else {
220 _value = -1;
221 }
222 *_result = _value;
223 }
224
225 /* Find the first bit clear in bit string at or after bit start. */
226 static inline void
227 bit_ffc_at(bitstr_t *_bitstr, int _start, int _nbits, int *_result)
228 {
229 bitstr_t *_curbitstr;
230 bitstr_t *_stopbitstr;
231 bitstr_t _test;
232 int _value, _offset;
233
234 if (_nbits > 0) {
235 _curbitstr = _bitstr + _bit_idx(_start);
236 _stopbitstr = _bitstr + _bit_idx(_nbits - 1);
237
238 _test = *_curbitstr;
239 if (_bit_offset(_start) != 0)
240 _test |= _bit_make_mask(0, _start - 1);
241 while (_test == _BITSTR_MASK && _curbitstr < _stopbitstr)
242 _test = *(++_curbitstr);
243
244 _offset = ffsl(~_test);
245 _value = ((_curbitstr - _bitstr) * _BITSTR_BITS) + _offset - 1;
246 if (_offset == 0 || _value >= _nbits)
247 _value = -1;
248 } else {
249 _value = -1;
250 }
251 *_result = _value;
252 }
253
254 /* Find the first bit set in bit string. */
255 static inline void
256 bit_ffs(bitstr_t *_bitstr, int _nbits, int *_result)
257 {
258 bit_ffs_at(_bitstr, /*start*/0, _nbits, _result);
259 }
260
261 /* Find the first bit clear in bit string. */
262 static inline void
263 bit_ffc(bitstr_t *_bitstr, int _nbits, int *_result)
264 {
265 bit_ffc_at(_bitstr, /*start*/0, _nbits, _result);
266 }
267
268 /* Count the number of bits set in a bitstr of size _nbits at or after _start */
269 static inline void
270 bit_count(bitstr_t *_bitstr, int _start, int _nbits, int *_result)
271 {
272 bitstr_t *_curbitstr, mask;
273 int _value = 0, curbitstr_len;
274
275 if (_start >= _nbits)
276 goto out;
277
278 _curbitstr = _bitstr + _bit_idx(_start);
279 _nbits -= _BITSTR_BITS * _bit_idx(_start);
280 _start -= _BITSTR_BITS * _bit_idx(_start);
281
282 if (_start > 0) {
283 curbitstr_len = (int)_BITSTR_BITS < _nbits ?
284 (int)_BITSTR_BITS : _nbits;
285 mask = _bit_make_mask(_start, _bit_offset(curbitstr_len - 1));
286 _value += __bitcountl(*_curbitstr & mask);
287 _curbitstr++;
288 _nbits -= _BITSTR_BITS;
289 }
290 while (_nbits >= (int)_BITSTR_BITS) {
291 _value += __bitcountl(*_curbitstr);
292 _curbitstr++;
293 _nbits -= _BITSTR_BITS;
294 }
295 if (_nbits > 0) {
296 mask = _bit_make_mask(0, _bit_offset(_nbits - 1));
297 _value += __bitcountl(*_curbitstr & mask);
298 }
299
300 out:
301 *_result = _value;
302 }
303
304 #endif /* _SYS_BITSTRING_H_ */
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