The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/sys/bitstring.h

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    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: stable/12/sys/sys/bitstring.h 356306 2020-01-02 23:16:27Z erj $
   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 #endif  /* _SYS_BITSTRING_H_ */

Cache object: 788f1dda6e0524976745db2f5402bd50


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.