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/* $OpenBSD: bitstring.h,v 1.4 2006/01/08 21:05:40 miod Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Paul Vixie.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)bitstring.h 8.1 (Berkeley) 7/19/93
*/
#ifndef _BITSTRING_H_
#define _BITSTRING_H_
typedef unsigned char bitstr_t;
/* internal macros */
/* byte of the bitstring bit is in */
#define _bit_byte(bit) \
((bit) >> 3)
/* mask for the bit within its byte */
#define _bit_mask(bit) \
(1 << ((bit)&0x7))
/* external macros */
/* bytes in a bitstring of nbits bits */
#define bitstr_size(nbits) \
((((nbits) - 1) >> 3) + 1)
/* allocate a bitstring */
#define bit_alloc(nbits) \
(bitstr_t *)calloc(1, \
(unsigned int)bitstr_size(nbits) * sizeof(bitstr_t))
/* allocate a bitstring on the stack */
#define bit_decl(name, nbits) \
(name)[bitstr_size(nbits)]
/* is bit N of bitstring name set? */
#define bit_test(name, bit) \
((name)[_bit_byte(bit)] & _bit_mask(bit))
/* set bit N of bitstring name */
#define bit_set(name, bit) \
(name)[_bit_byte(bit)] |= _bit_mask(bit)
/* clear bit N of bitstring name */
#define bit_clear(name, bit) \
(name)[_bit_byte(bit)] &= ~_bit_mask(bit)
/* clear bits start ... stop in bitstring */
#define bit_nclear(name, start, stop) { \
register bitstr_t *_name = (name); \
register int _start = (start), _stop = (stop); \
register int _startbyte = _bit_byte(_start); \
register int _stopbyte = _bit_byte(_stop); \
if (_startbyte == _stopbyte) { \
_name[_startbyte] &= ((0xff >> (8 - (_start&0x7))) | \
(0xff << ((_stop&0x7) + 1))); \
} else { \
_name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
while (++_startbyte < _stopbyte) \
_name[_startbyte] = 0; \
_name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
} \
}
/* set bits start ... stop in bitstring */
#define bit_nset(name, start, stop) { \
register bitstr_t *_name = (name); \
register int _start = (start), _stop = (stop); \
register int _startbyte = _bit_byte(_start); \
register int _stopbyte = _bit_byte(_stop); \
if (_startbyte == _stopbyte) { \
_name[_startbyte] |= ((0xff << (_start&0x7)) & \
(0xff >> (7 - (_stop&0x7)))); \
} else { \
_name[_startbyte] |= 0xff << ((_start)&0x7); \
while (++_startbyte < _stopbyte) \
_name[_startbyte] = 0xff; \
_name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
} \
}
/* find first bit clear in name */
#define bit_ffc(name, nbits, value) { \
register bitstr_t *_name = (name); \
register int _byte, _nbits = (nbits); \
register int _stopbyte = _bit_byte(_nbits), _value = -1; \
for (_byte = 0; _byte <= _stopbyte; ++_byte) \
if (_name[_byte] != 0xff) { \
_value = _byte << 3; \
for (_stopbyte = _name[_byte]; (_stopbyte&0x1); \
++_value, _stopbyte >>= 1); \
break; \
} \
*(value) = _value; \
}
/* find first bit set in name */
#define bit_ffs(name, nbits, value) { \
register bitstr_t *_name = (name); \
register int _byte, _nbits = (nbits); \
register int _stopbyte = _bit_byte(_nbits), _value = -1; \
for (_byte = 0; _byte <= _stopbyte; ++_byte) \
if (_name[_byte]) { \
_value = _byte << 3; \
for (_stopbyte = _name[_byte]; !(_stopbyte&0x1); \
++_value, _stopbyte >>= 1); \
break; \
} \
*(value) = _value; \
}
#endif /* !_BITSTRING_H_ */
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