118 lines
3.7 KiB
C
118 lines
3.7 KiB
C
/*
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* Copyright (c) 1989 The Regents of the University of California.
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* 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 are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the University of California, Berkeley. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* @(#)bitstring.h 5.2 (Berkeley) 4/4/90
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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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((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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(1 << ((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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((((nbits) - 1) >> 3) + 1)
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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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((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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(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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(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) { \
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register bitstr_t *_name = name; \
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register int _start = start, _stop = stop; \
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register int _startbyte = _bit_byte(_start); \
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register int _stopbyte = _bit_byte(_stop); \
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if (_startbyte == _stopbyte) { \
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_name[_startbyte] &= ((0xff >> (8 - (_start&0x7))) | \
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(0xff << ((_stop&0x7) + 1))); \
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} else { \
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_name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
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while (++_startbyte < _stopbyte) \
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_name[_startbyte] = 0; \
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_name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
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} \
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}
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/* set bits start ... stop in bitstring */
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#define bit_nset(name, start, stop) { \
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register bitstr_t *_name = name; \
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register int _start = start, _stop = stop; \
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register int _startbyte = _bit_byte(_start); \
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register int _stopbyte = _bit_byte(_stop); \
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if (_startbyte == _stopbyte) { \
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_name[_startbyte] |= ((0xff << (_start&0x7)) & \
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(0xff >> (7 - (_stop&0x7)))); \
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} else { \
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_name[_startbyte] |= 0xff << ((_start)&0x7); \
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while (++_startbyte < _stopbyte) \
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_name[_startbyte] = 0xff; \
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_name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
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} \
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}
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/* find first bit clear in name */
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#define bit_ffc(name, nbits, value) { \
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register bitstr_t *_name = name; \
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register int _byte, _nbits = nbits; \
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register int _stopbyte = _bit_byte(_nbits), _value = -1; \
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for (_byte = 0; _byte <= _stopbyte; ++_byte) \
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if (_name[_byte] != 0xff) { \
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_value = _byte << 3; \
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for (_stopbyte = _name[_byte]; (_stopbyte&0x1); \
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++_value, _stopbyte >>= 1); \
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break; \
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} \
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*(value) = _value; \
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}
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/* find first bit set in name */
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#define bit_ffs(name, nbits, value) { \
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register bitstr_t *_name = name; \
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register int _byte, _nbits = nbits; \
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register int _stopbyte = _bit_byte(_nbits), _value = -1; \
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for (_byte = 0; _byte <= _stopbyte; ++_byte) \
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if (_name[_byte]) { \
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_value = _byte << 3; \
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for (_stopbyte = _name[_byte]; !(_stopbyte&0x1); \
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++_value, _stopbyte >>= 1); \
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break; \
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} \
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*(value) = _value; \
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}
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