fbbd9655e5
Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96
303 lines
8.9 KiB
C
303 lines
8.9 KiB
C
/*-
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Paul Vixie.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* Copyright (c) 2014 Spectra Logic Corporation
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification.
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* 2. Redistributions in binary form must reproduce at minimum a disclaimer
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* substantially similar to the "NO WARRANTY" disclaimer below
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* ("Disclaimer") and any redistribution must be conditioned upon
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* including a substantially similar Disclaimer requirement for further
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* binary redistribution.
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*
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* NO WARRANTY
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGES.
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*
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* $FreeBSD$
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*/
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#ifndef _SYS_BITSTRING_H_
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#define _SYS_BITSTRING_H_
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#ifdef _KERNEL
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#include <sys/libkern.h>
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#include <sys/malloc.h>
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#endif
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#include <sys/types.h>
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typedef unsigned long bitstr_t;
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/*---------------------- Private Implementation Details ----------------------*/
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#define _BITSTR_MASK (~0UL)
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#define _BITSTR_BITS (sizeof(bitstr_t) * 8)
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#ifdef roundup2
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#define _bit_roundup2 roundup2
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#else
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#define _bit_roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
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#endif
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/* bitstr_t in bit string containing the bit. */
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static inline int
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_bit_idx(int _bit)
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{
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return (_bit / _BITSTR_BITS);
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}
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/* bit number within bitstr_t at _bit_idx(_bit). */
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static inline int
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_bit_offset(int _bit)
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{
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return (_bit % _BITSTR_BITS);
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}
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/* Mask for the bit within its long. */
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static inline bitstr_t
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_bit_mask(int _bit)
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{
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return (1UL << _bit_offset(_bit));
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}
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static inline bitstr_t
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_bit_make_mask(int _start, int _stop)
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{
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return ((_BITSTR_MASK << _bit_offset(_start)) &
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(_BITSTR_MASK >> (_BITSTR_BITS - _bit_offset(_stop) - 1)));
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}
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/*----------------------------- Public Interface -----------------------------*/
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/* Number of bytes allocated for a bit string of nbits bits */
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#define bitstr_size(_nbits) (_bit_roundup2(_nbits, _BITSTR_BITS) / 8)
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/* Allocate a bit string initialized with no bits set. */
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#ifdef _KERNEL
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static inline bitstr_t *
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bit_alloc(int _nbits, struct malloc_type *type, int flags)
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{
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return ((bitstr_t *)malloc(bitstr_size(_nbits), type, flags | M_ZERO));
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}
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#else
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static inline bitstr_t *
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bit_alloc(int _nbits)
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{
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return ((bitstr_t *)calloc(bitstr_size(_nbits), 1));
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}
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#endif
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/* Allocate a bit string on the stack */
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#define bit_decl(name, nbits) \
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((name)[bitstr_size(nbits) / sizeof(bitstr_t)])
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/* Is bit N of bit string set? */
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static inline int
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bit_test(const bitstr_t *_bitstr, int _bit)
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{
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return ((_bitstr[_bit_idx(_bit)] & _bit_mask(_bit)) != 0);
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}
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/* Set bit N of bit string. */
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static inline void
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bit_set(bitstr_t *_bitstr, int _bit)
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{
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_bitstr[_bit_idx(_bit)] |= _bit_mask(_bit);
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}
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/* clear bit N of bit string name */
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static inline void
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bit_clear(bitstr_t *_bitstr, int _bit)
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{
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_bitstr[_bit_idx(_bit)] &= ~_bit_mask(_bit);
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}
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/* Set bits start ... stop inclusive in bit string. */
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static inline void
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bit_nset(bitstr_t *_bitstr, int _start, int _stop)
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{
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bitstr_t *_stopbitstr;
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_stopbitstr = _bitstr + _bit_idx(_stop);
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_bitstr += _bit_idx(_start);
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if (_bitstr == _stopbitstr) {
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*_bitstr |= _bit_make_mask(_start, _stop);
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} else {
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*_bitstr |= _bit_make_mask(_start, _BITSTR_BITS - 1);
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while (++_bitstr < _stopbitstr)
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*_bitstr = _BITSTR_MASK;
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*_stopbitstr |= _bit_make_mask(0, _stop);
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}
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}
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/* Clear bits start ... stop inclusive in bit string. */
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static inline void
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bit_nclear(bitstr_t *_bitstr, int _start, int _stop)
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{
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bitstr_t *_stopbitstr;
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_stopbitstr = _bitstr + _bit_idx(_stop);
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_bitstr += _bit_idx(_start);
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if (_bitstr == _stopbitstr) {
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*_bitstr &= ~_bit_make_mask(_start, _stop);
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} else {
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*_bitstr &= ~_bit_make_mask(_start, _BITSTR_BITS - 1);
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while (++_bitstr < _stopbitstr)
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*_bitstr = 0;
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*_stopbitstr &= ~_bit_make_mask(0, _stop);
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}
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}
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/* Find the first bit set in bit string at or after bit start. */
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static inline void
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bit_ffs_at(bitstr_t *_bitstr, int _start, int _nbits, int *_result)
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{
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bitstr_t *_curbitstr;
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bitstr_t *_stopbitstr;
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bitstr_t _test;
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int _value, _offset;
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if (_nbits > 0) {
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_curbitstr = _bitstr + _bit_idx(_start);
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_stopbitstr = _bitstr + _bit_idx(_nbits - 1);
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_test = *_curbitstr;
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if (_bit_offset(_start) != 0)
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_test &= _bit_make_mask(_start, _BITSTR_BITS - 1);
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while (_test == 0 && _curbitstr < _stopbitstr)
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_test = *(++_curbitstr);
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_offset = ffsl(_test);
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_value = ((_curbitstr - _bitstr) * _BITSTR_BITS) + _offset - 1;
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if (_offset == 0 || _value >= _nbits)
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_value = -1;
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} else {
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_value = -1;
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}
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*_result = _value;
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}
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/* Find the first bit clear in bit string at or after bit start. */
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static inline void
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bit_ffc_at(bitstr_t *_bitstr, int _start, int _nbits, int *_result)
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{
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bitstr_t *_curbitstr;
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bitstr_t *_stopbitstr;
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bitstr_t _test;
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int _value, _offset;
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if (_nbits > 0) {
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_curbitstr = _bitstr + _bit_idx(_start);
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_stopbitstr = _bitstr + _bit_idx(_nbits - 1);
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_test = *_curbitstr;
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if (_bit_offset(_start) != 0)
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_test |= _bit_make_mask(0, _start - 1);
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while (_test == _BITSTR_MASK && _curbitstr < _stopbitstr)
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_test = *(++_curbitstr);
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_offset = ffsl(~_test);
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_value = ((_curbitstr - _bitstr) * _BITSTR_BITS) + _offset - 1;
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if (_offset == 0 || _value >= _nbits)
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_value = -1;
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} else {
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_value = -1;
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}
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*_result = _value;
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}
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/* Find the first bit set in bit string. */
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static inline void
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bit_ffs(bitstr_t *_bitstr, int _nbits, int *_result)
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{
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bit_ffs_at(_bitstr, /*start*/0, _nbits, _result);
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}
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/* Find the first bit clear in bit string. */
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static inline void
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bit_ffc(bitstr_t *_bitstr, int _nbits, int *_result)
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{
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bit_ffc_at(_bitstr, /*start*/0, _nbits, _result);
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}
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/* Count the number of bits set in a bitstr of size _nbits at or after _start */
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static inline void
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bit_count(bitstr_t *_bitstr, int _start, int _nbits, int *_result)
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{
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bitstr_t *_curbitstr, mask;
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int _value = 0, curbitstr_len;
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if (_start >= _nbits)
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goto out;
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_curbitstr = _bitstr + _bit_idx(_start);
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_nbits -= _BITSTR_BITS * _bit_idx(_start);
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_start -= _BITSTR_BITS * _bit_idx(_start);
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if (_start > 0) {
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curbitstr_len = (int)_BITSTR_BITS < _nbits ?
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(int)_BITSTR_BITS : _nbits;
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mask = _bit_make_mask(_start, _bit_offset(curbitstr_len - 1));
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_value += __bitcountl(*_curbitstr & mask);
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_curbitstr++;
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_nbits -= _BITSTR_BITS;
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}
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while (_nbits >= (int)_BITSTR_BITS) {
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_value += __bitcountl(*_curbitstr);
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_curbitstr++;
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_nbits -= _BITSTR_BITS;
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}
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if (_nbits > 0) {
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mask = _bit_make_mask(0, _bit_offset(_nbits - 1));
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_value += __bitcountl(*_curbitstr & mask);
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}
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out:
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*_result = _value;
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}
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#endif /* _SYS_BITSTRING_H_ */
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