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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* 4. 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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