135 lines
4.5 KiB
C
135 lines
4.5 KiB
C
/* $NetBSD: bitstring.h,v 1.9 2010/05/06 18:54:22 christos Exp $ */
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/*
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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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* @(#)bitstring.h 8.1 (Berkeley) 7/19/93
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*/
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#ifndef _BITSTRING_H_
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#define _BITSTRING_H_
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/* modified for SV/AT and bitstring bugfix by M.R.Murphy, 11oct91
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* bitstr_size changed gratuitously, but shorter
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* bit_alloc spelling error fixed
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* the following were efficient, but didn't work, they've been made to
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* work, but are no longer as efficient :-)
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* bit_nclear, bit_nset, bit_ffc, bit_ffs
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*/
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/*
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* The comment above may or may not bear any resemblance to reality.
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* This code has been maintained in a confusing way, with little
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* information available on the provenance of much of it. "At least it
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* works."
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* /s/ Perry E. Metzger, 2 Feb 98
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*/
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typedef unsigned char bitstr_t;
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/* internal macros */
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/* byte of the bitstring bit is in */
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#define _bit_byte(bit) \
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(uint32_t)((bit) >> 3)
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/* mask for the bit within its byte */
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#define _bit_mask(bit) \
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(uint32_t)((1 << (uint32_t)((bit)&0x7)))
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/* external macros */
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/* bytes in a bitstring of nbits bits */
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#define bitstr_size(nbits) \
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(size_t)((uint32_t)((nbits) + 7) >> 3)
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/* allocate a bitstring */
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#define bit_alloc(nbits) \
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calloc(bitstr_size(nbits), sizeof(bitstr_t))
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/* allocate a bitstring on the stack */
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#define bit_decl(name, nbits) \
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((name)[bitstr_size(nbits)])
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/* is bit N of bitstring name set? */
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#define bit_test(name, bit) \
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/*LINTED bitwise on signed*/((name)[_bit_byte(bit)] & _bit_mask(bit))
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/* set bit N of bitstring name */
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#define bit_set(name, bit) \
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/*LINTED bitwise on signed*/((name)[_bit_byte(bit)] |= _bit_mask(bit))
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/* clear bit N of bitstring name */
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#define bit_clear(name, bit) \
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/*LINTED bitwise on signed*/((name)[_bit_byte(bit)] &= ~_bit_mask(bit))
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/* clear bits start ... stop in bitstring */
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#define bit_nclear(name, start, stop) do { \
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bitstr_t *_name = name; \
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int _start = start, _stop = stop; \
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while (_start <= _stop) { \
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bit_clear(_name, _start); \
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_start++; \
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} \
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} while(/*CONSTCOND*/0)
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/* set bits start ... stop in bitstring */
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#define bit_nset(name, start, stop) do { \
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bitstr_t *_name = name; \
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int _start = start, _stop = stop; \
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while (_start <= _stop) { \
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bit_set(_name, _start); \
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_start++; \
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} \
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} while(/*CONSTCOND*/0)
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/* find first bit clear in name */
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#define bit_ffc(name, nbits, value) do { \
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bitstr_t *_name = name; \
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int _bit, _nbits = nbits, _value = -1; \
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for (_bit = 0; _bit < _nbits; ++_bit) \
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if (!bit_test(_name, _bit)) { \
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_value = _bit; \
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break; \
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} \
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*(value) = _value; \
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} while(/*CONSTCOND*/0)
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/* find first bit set in name */
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#define bit_ffs(name, nbits, value) do { \
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bitstr_t *_name = name; \
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int _bit, _nbits = nbits, _value = -1; \
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for (_bit = 0; _bit < _nbits; ++_bit) \
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if (bit_test(_name, _bit)) { \
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_value = _bit; \
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break; \
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} \
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*(value) = _value; \
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} while(/*CONSTCOND*/0)
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#endif /* !_BITSTRING_H_ */
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