root/src/bitstring.h

/*   */

INCLUDED FROM

   1 /*      $NetBSD: bitstring.h,v 1.3 2003/08/07 11:17:08 agc Exp $        */
   2 
   3 /*
   4  * Copyright (c) 1989, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Paul Vixie.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)bitstring.h 8.1 (Berkeley) 7/19/93
  35  */
  36 
  37 #ifndef _BITSTRING_H_
  38 #define _BITSTRING_H_
  39 
  40 typedef unsigned char bitstr_t;
  41 
  42 /* internal macros */
  43                                 /* byte of the bitstring bit is in */
  44 #define _bit_byte(bit) \
  45         ((bit) >> 3)
  46 
  47                                 /* mask for the bit within its byte */
  48 #define _bit_mask(bit) \
  49         (1 << ((bit)&0x7))
  50 
  51 /* external macros */
  52                                 /* bytes in a bitstring of nbits bits */
  53 #define bitstr_size(nbits) \
  54         ((((nbits) - 1) >> 3) + 1)
  55 
  56                                 /* allocate a bitstring */
  57 #define bit_alloc(nbits) \
  58         (bitstr_t *)calloc(1, \
  59             (unsigned int)bitstr_size(nbits) * sizeof(bitstr_t))
  60 
  61                                 /* allocate a bitstring on the stack */
  62 #define bit_decl(name, nbits) \
  63         (name)[bitstr_size(nbits)]
  64 
  65                                 /* is bit N of bitstring name set? */
  66 #define bit_test(name, bit) \
  67         ((name)[_bit_byte(bit)] & _bit_mask(bit))
  68 
  69                                 /* set bit N of bitstring name */
  70 #define bit_set(name, bit) \
  71         (name)[_bit_byte(bit)] |= (bitstr_t)_bit_mask(bit)
  72 
  73                                 /* clear bit N of bitstring name */
  74 #define bit_clear(name, bit) \
  75         (name)[_bit_byte(bit)] &= (bitstr_t)~_bit_mask(bit)
  76 
  77                                 /* clear bits start ... stop in bitstring */
  78 #define bit_nclear(name, start, stop) { \
  79         register bitstr_t *_name = name; \
  80         register int _start = start, _stop = stop; \
  81         register int _startbyte = _bit_byte(_start); \
  82         register int _stopbyte = _bit_byte(_stop); \
  83         if (_startbyte == _stopbyte) { \
  84                 _name[_startbyte] &= (bitstr_t)((0xff >> (8 - (_start&0x7))) | \
  85                                       (0xff << ((_stop&0x7) + 1))); \
  86         } else { \
  87                 _name[_startbyte] &= (bitstr_t)(0xff >> (8 - (_start&0x7))); \
  88                 while (++_startbyte < _stopbyte) \
  89                         _name[_startbyte] = 0; \
  90                 _name[_stopbyte] &= (bitstr_t)(0xff << ((_stop&0x7) + 1)); \
  91         } \
  92 }
  93 
  94                                 /* set bits start ... stop in bitstring */
  95 #define bit_nset(name, start, stop) { \
  96         register bitstr_t *_name = name; \
  97         register int _start = start, _stop = stop; \
  98         register int _startbyte = _bit_byte(_start); \
  99         register int _stopbyte = _bit_byte(_stop); \
 100         if (_startbyte == _stopbyte) { \
 101                 _name[_startbyte] |= (bitstr_t)((0xff << (_start&0x7)) & \
 102                                     (0xff >> (7 - (_stop&0x7)))); \
 103         } else { \
 104                 _name[_startbyte] |= (bitstr_t)(0xff << ((_start)&0x7)); \
 105                 while (++_startbyte < _stopbyte) \
 106                         _name[_startbyte] = 0xff; \
 107                 _name[_stopbyte] |= (bitstr_t)(0xff >> (7 - (_stop&0x7))); \
 108         } \
 109 }
 110 
 111                                 /* find first bit clear in name */
 112 #define bit_ffc(name, nbits, value) { \
 113         register bitstr_t *_name = name; \
 114         register int _byte, _nbits = nbits; \
 115         register int _stopbyte = _bit_byte(_nbits), _value = -1; \
 116         for (_byte = 0; _byte <= _stopbyte; ++_byte) \
 117                 if (_name[_byte] != 0xff) { \
 118                         _value = _byte << 3; \
 119                         for (_stopbyte = _name[_byte]; (_stopbyte&0x1); \
 120                             ++_value, _stopbyte >>= 1); \
 121                         break; \
 122                 } \
 123         *(value) = _value; \
 124 }
 125 
 126                                 /* find first bit set in name */
 127 #define bit_ffs(name, nbits, value) { \
 128         register bitstr_t *_name = name; \
 129         register int _byte, _nbits = nbits; \
 130         register int _stopbyte = _bit_byte(_nbits), _value = -1; \
 131         for (_byte = 0; _byte <= _stopbyte; ++_byte) \
 132                 if (_name[_byte]) { \
 133                         _value = _byte << 3; \
 134                         for (_stopbyte = _name[_byte]; !(_stopbyte&0x1); \
 135                             ++_value, _stopbyte >>= 1); \
 136                         break; \
 137                 } \
 138         *(value) = _value; \
 139 }
 140 
 141 #endif /* !_BITSTRING_H_ */

/*   */