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 * $FreeBSD$ 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 (_start >= _nbits) { 206 *_result = -1; 207 return; 208 } 209 210 if (_nbits > 0) { 211 _curbitstr = _bitstr + _bit_idx(_start); 212 _stopbitstr = _bitstr + _bit_idx(_nbits - 1); 213 214 _test = *_curbitstr; 215 if (_bit_offset(_start) != 0) 216 _test &= _bit_make_mask(_start, _BITSTR_BITS - 1); 217 while (_test == 0 && _curbitstr < _stopbitstr) 218 _test = *(++_curbitstr); 219 220 _offset = ffsl(_test); 221 _value = ((_curbitstr - _bitstr) * _BITSTR_BITS) + _offset - 1; 222 if (_offset == 0 || _value >= _nbits) 223 _value = -1; 224 } else { 225 _value = -1; 226 } 227 *_result = _value; 228 } 229 230 /* Find the first bit clear in bit string at or after bit start. */ 231 static inline void 232 bit_ffc_at(bitstr_t *_bitstr, int _start, int _nbits, int *_result) 233 { 234 bitstr_t *_curbitstr; 235 bitstr_t *_stopbitstr; 236 bitstr_t _test; 237 int _value, _offset; 238 239 if (_start >= _nbits) { 240 *_result = -1; 241 return; 242 } 243 244 if (_nbits > 0) { 245 _curbitstr = _bitstr + _bit_idx(_start); 246 _stopbitstr = _bitstr + _bit_idx(_nbits - 1); 247 248 _test = *_curbitstr; 249 if (_bit_offset(_start) != 0) 250 _test |= _bit_make_mask(0, _start - 1); 251 while (_test == _BITSTR_MASK && _curbitstr < _stopbitstr) 252 _test = *(++_curbitstr); 253 254 _offset = ffsl(~_test); 255 _value = ((_curbitstr - _bitstr) * _BITSTR_BITS) + _offset - 1; 256 if (_offset == 0 || _value >= _nbits) 257 _value = -1; 258 } else { 259 _value = -1; 260 } 261 *_result = _value; 262 } 263 264 /* Find the first bit set in bit string. */ 265 static inline void 266 bit_ffs(bitstr_t *_bitstr, int _nbits, int *_result) 267 { 268 bit_ffs_at(_bitstr, /*start*/0, _nbits, _result); 269 } 270 271 /* Find the first bit clear in bit string. */ 272 static inline void 273 bit_ffc(bitstr_t *_bitstr, int _nbits, int *_result) 274 { 275 bit_ffc_at(_bitstr, /*start*/0, _nbits, _result); 276 } 277 278 /* Find contiguous sequence of at least size set bits at or after start */ 279 static inline void 280 bit_ffs_area_at(bitstr_t *_bitstr, int _start, int _nbits, int _size, 281 int *_result) 282 { 283 bitstr_t *_curbitstr; 284 bitstr_t _test; 285 int _value, _offset, _logsize, _b; 286 287 if (_start + _size > _nbits || _nbits <= 0) { 288 *_result = -1; 289 return; 290 } 291 292 _logsize = fls(_size - 1); 293 _value = _start; 294 _curbitstr = _bitstr + _bit_idx(_start); 295 _test = ~*_curbitstr; 296 if (_bit_offset(_start) != 0) 297 _test |= _bit_make_mask(0, _start - 1); 298 for (_offset = 0;; _offset -= _BITSTR_BITS, _test = ~*++_curbitstr) { 299 if (_test != 0) { 300 /* If leading 0s in _test can finish 0-area, stop. */ 301 if (_offset + _size < (int)_BITSTR_BITS && 302 (_test & _bit_make_mask(0, _offset + _size)) == 0) 303 break; 304 /* Shrink-left every 0-area in _test by size-1 bits. */ 305 _b = _logsize; 306 while ((_test & (_test + 1)) != 0 && _b-- > 0) 307 _test |= _test >> (((_size - 1) >> _b) + 1) / 2; 308 /* Find the start of the first 0-area in _test. */ 309 _offset = (~_test == 0) ? (int)_BITSTR_BITS : 310 ffsl(~_test) - 1; 311 _value = (_curbitstr - _bitstr) * _BITSTR_BITS + 312 _offset; 313 /* If there's insufficient space left, give up. */ 314 if (_value + _size > _nbits) { 315 _value = -1; 316 break; 317 } 318 } 319 if (_offset + _size <= (int)_BITSTR_BITS) 320 break; 321 } 322 *_result = _value; 323 } 324 325 /* Find contiguous sequence of at least size cleared bits at or after start */ 326 static inline void 327 bit_ffc_area_at(bitstr_t *_bitstr, int _start, int _nbits, int _size, 328 int *_result) 329 { 330 bitstr_t *_curbitstr; 331 bitstr_t _test; 332 int _value, _offset, _logsize, _b; 333 334 if (_start + _size > _nbits || _nbits <= 0) { 335 *_result = -1; 336 return; 337 } 338 339 _logsize = fls(_size - 1); 340 _value = _start; 341 _curbitstr = _bitstr + _bit_idx(_start); 342 _test = *_curbitstr; 343 if (_bit_offset(_start) != 0) 344 _test |= _bit_make_mask(0, _start - 1); 345 for (_offset = 0;; _offset -= _BITSTR_BITS, _test = *++_curbitstr) { 346 if (_test != 0) { 347 /* If leading 0s in _test can finish 0-area, stop. */ 348 if (_offset + _size < (int)_BITSTR_BITS && 349 (_test & _bit_make_mask(0, _offset + _size)) == 0) 350 break; 351 /* Shrink-left every 0-area in _test by size-1 bits. */ 352 _b = _logsize; 353 while ((_test & (_test + 1)) != 0 && _b-- > 0) 354 _test |= _test >> (((_size - 1) >> _b) + 1) / 2; 355 /* Find the start of the first 0-area in _test. */ 356 _offset = (~_test == 0) ? (int)_BITSTR_BITS : 357 ffsl(~_test) - 1; 358 _value = (_curbitstr - _bitstr) * _BITSTR_BITS + 359 _offset; 360 /* If there's insufficient space left, give up. */ 361 if (_value + _size > _nbits) { 362 _value = -1; 363 break; 364 } 365 } 366 if (_offset + _size <= (int)_BITSTR_BITS) 367 break; 368 } 369 *_result = _value; 370 } 371 372 /* Find contiguous sequence of at least size set bits in bit string */ 373 static inline void 374 bit_ffs_area(bitstr_t *_bitstr, int _nbits, int _size, int *_result) 375 { 376 bit_ffs_area_at(_bitstr, /*start*/0, _nbits, _size, _result); 377 } 378 379 /* Find contiguous sequence of at least size cleared bits in bit string */ 380 static inline void 381 bit_ffc_area(bitstr_t *_bitstr, int _nbits, int _size, int *_result) 382 { 383 bit_ffc_area_at(_bitstr, /*start*/0, _nbits, _size, _result); 384 } 385 386 /* Count the number of bits set in a bitstr of size _nbits at or after _start */ 387 static inline void 388 bit_count(bitstr_t *_bitstr, int _start, int _nbits, int *_result) 389 { 390 bitstr_t *_curbitstr, mask; 391 int _value = 0, curbitstr_len; 392 393 if (_start >= _nbits) 394 goto out; 395 396 _curbitstr = _bitstr + _bit_idx(_start); 397 _nbits -= _BITSTR_BITS * _bit_idx(_start); 398 _start -= _BITSTR_BITS * _bit_idx(_start); 399 400 if (_start > 0) { 401 curbitstr_len = (int)_BITSTR_BITS < _nbits ? 402 (int)_BITSTR_BITS : _nbits; 403 mask = _bit_make_mask(_start, _bit_offset(curbitstr_len - 1)); 404 _value += __bitcountl(*_curbitstr & mask); 405 _curbitstr++; 406 _nbits -= _BITSTR_BITS; 407 } 408 while (_nbits >= (int)_BITSTR_BITS) { 409 _value += __bitcountl(*_curbitstr); 410 _curbitstr++; 411 _nbits -= _BITSTR_BITS; 412 } 413 if (_nbits > 0) { 414 mask = _bit_make_mask(0, _bit_offset(_nbits - 1)); 415 _value += __bitcountl(*_curbitstr & mask); 416 } 417 418 out: 419 *_result = _value; 420 } 421 422 /* Traverse all set bits, assigning each location in turn to iter */ 423 #define bit_foreach_at(_bitstr, _start, _nbits, _iter) \ 424 for (bit_ffs_at((_bitstr), (_start), (_nbits), &(_iter)); \ 425 (_iter) != -1; \ 426 bit_ffs_at((_bitstr), (_iter) + 1, (_nbits), &(_iter))) 427 #define bit_foreach(_bitstr, _nbits, _iter) \ 428 bit_foreach_at(_bitstr, /*start*/0, _nbits, _iter) 429 430 /* Traverse all unset bits, assigning each location in turn to iter */ 431 #define bit_foreach_unset_at(_bitstr, _start, _nbits, _iter) \ 432 for (bit_ffc_at((_bitstr), (_start), (_nbits), &(_iter)); \ 433 (_iter) != -1; \ 434 bit_ffc_at((_bitstr), (_iter) + 1, (_nbits), &(_iter))) 435 #define bit_foreach_unset(_bitstr, _nbits, _iter) \ 436 bit_foreach_unset_at(_bitstr, /*start*/0, _nbits, _iter) 437 438 #endif /* _SYS_BITSTRING_H_ */ 439