include/bitstring.h

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Paul Vixie.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * $FreeBSD: src/include/bitstring.h,v 1.1.1.1.14.1 2000/10/30 11:21:04 dwmalone Exp $
  37  * $DragonFly: src/include/bitstring.h,v 1.3 2007/04/18 18:39:11 swildner Exp $
  38  */
  39
  40 #ifndef _BITSTRING_H_
  41 #define _BITSTRING_H_
  42
  43 typedef unsigned char bitstr_t;
  44
  45 /* internal macros */
  46                                 /* byte of the bitstring bit is in */
  47 #define _bit_byte(bit) \
  48         ((bit) >> 3)
  49
  50                                 /* mask for the bit within its byte */
  51 #define _bit_mask(bit) \
  52         (1 << ((bit)&0x7))
  53
  54 /* external macros */
  55                                 /* bytes in a bitstring of nbits bits */
  56 #define bitstr_size(nbits) \
  57         (((nbits) + 7) >> 3)
  58
  59                                 /* allocate a bitstring */
  60 #define bit_alloc(nbits) \
  61         (bitstr_t *)calloc((size_t)bitstr_size(nbits), sizeof(bitstr_t))
  62
  63                                 /* allocate a bitstring on the stack */
  64 #define bit_decl(name, nbits) \
  65         ((name)[bitstr_size(nbits)])
  66
  67                                 /* is bit N of bitstring name set? */
  68 #define bit_test(name, bit) \
  69         ((name)[_bit_byte(bit)] & _bit_mask(bit))
  70
  71                                 /* set bit N of bitstring name */
  72 #define bit_set(name, bit) \
  73         ((name)[_bit_byte(bit)] |= _bit_mask(bit))
  74
  75                                 /* clear bit N of bitstring name */
  76 #define bit_clear(name, bit) \
  77         ((name)[_bit_byte(bit)] &= ~_bit_mask(bit))
  78
  79                                 /* clear bits start ... stop in bitstring */
  80 #define bit_nclear(name, start, stop) do { \
  81         bitstr_t *_name = (name); \
  82         int _start = (start), _stop = (stop); \
  83         int _startbyte = _bit_byte(_start); \
  84         int _stopbyte = _bit_byte(_stop); \
  85         if (_startbyte == _stopbyte) { \
  86                 _name[_startbyte] &= ((0xff >> (8 - (_start&0x7))) | \
  87                                       (0xff << ((_stop&0x7) + 1))); \
  88         } else { \
  89                 _name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \
  90                 while (++_startbyte < _stopbyte) \
  91                         _name[_startbyte] = 0; \
  92                 _name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \
  93         } \
  94 } while (0)
  95
  96                                 /* set bits start ... stop in bitstring */
  97 #define bit_nset(name, start, stop) do { \
  98         bitstr_t *_name = (name); \
  99         int _start = (start), _stop = (stop); \
 100         int _startbyte = _bit_byte(_start); \
 101         int _stopbyte = _bit_byte(_stop); \
 102         if (_startbyte == _stopbyte) { \
 103                 _name[_startbyte] |= ((0xff << (_start&0x7)) & \
 104                                     (0xff >> (7 - (_stop&0x7)))); \
 105         } else { \
 106                 _name[_startbyte] |= 0xff << ((_start)&0x7); \
 107                 while (++_startbyte < _stopbyte) \
 108                         _name[_startbyte] = 0xff; \
 109                 _name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \
 110         } \
 111 } while (0)
 112
 113                                 /* find first bit clear in name */
 114 #define bit_ffc(name, nbits, value) do { \
 115         bitstr_t *_name = (name); \
 116         int _byte, _nbits = (nbits); \
 117         int _stopbyte = _bit_byte(_nbits - 1), _value = -1; \
 118         if (_nbits > 0) \
 119                 for (_byte = 0; _byte <= _stopbyte; ++_byte) \
 120                         if (_name[_byte] != 0xff) { \
 121                                 bitstr_t _lb; \
 122                                 _value = _byte << 3; \
 123                                 for (_lb = _name[_byte]; (_lb&0x1); \
 124                                     ++_value, _lb >>= 1); \
 125                                 break; \
 126                         } \
 127         if (_value >= nbits) \
 128                 _value = -1; \
 129         *(value) = _value; \
 130 } while (0)
 131
 132                                 /* find first bit set in name */
 133 #define bit_ffs(name, nbits, value) do { \
 134         bitstr_t *_name = (name); \
 135         int _byte, _nbits = (nbits); \
 136         int _stopbyte = _bit_byte(_nbits - 1), _value = -1; \
 137         if (_nbits > 0) \
 138                 for (_byte = 0; _byte <= _stopbyte; ++_byte) \
 139                         if (_name[_byte]) { \
 140                                 bitstr_t _lb; \
 141                                 _value = _byte << 3; \
 142                                 for (_lb = _name[_byte]; !(_lb&0x1); \
 143                                     ++_value, _lb >>= 1); \
 144                                 break; \
 145                         } \
 146         if (_value >= nbits) \
 147                 _value = -1; \
 148         *(value) = _value; \
 149 } while (0)
 150
 151 #endif /* !_BITSTRING_H_ */