compat/bitstring.h

   1 /*      $OpenBSD: bitstring.h,v 1.5 2003/06/02 19:34:12 millert Exp $   */
   2 /*      $NetBSD: bitstring.h,v 1.5 1997/05/14 15:49:55 pk Exp $ */
   3
   4 /*
   5  * Copyright (c) 1989, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * This code is derived from software contributed to Berkeley by
   9  * Paul Vixie.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  *      @(#)bitstring.h 8.1 (Berkeley) 7/19/93
  36  */
  37
  38 #ifndef _BITSTRING_H_
  39 #define _BITSTRING_H_
  40
  41 /* modified for SV/AT and bitstring bugfix by M.R.Murphy, 11oct91
  42  * bitstr_size changed gratuitously, but shorter
  43  * bit_alloc   spelling error fixed
  44  * the following were efficient, but didn't work, they've been made to
  45  * work, but are no longer as efficient :-)
  46  * bit_nclear, bit_nset, bit_ffc, bit_ffs
  47  */
  48 typedef unsigned char bitstr_t;
  49
  50 /* internal macros */
  51                                 /* byte of the bitstring bit is in */
  52 #define _bit_byte(bit) \
  53         ((bit) >> 3)
  54
  55                                 /* mask for the bit within its byte */
  56 #define _bit_mask(bit) \
  57         (1 << ((bit)&0x7))
  58
  59 /* external macros */
  60                                 /* bytes in a bitstring of nbits bits */
  61 #define bitstr_size(nbits) \
  62         (((nbits) + 7) >> 3)
  63
  64                                 /* allocate a bitstring */
  65 #define bit_alloc(nbits) \
  66         (bitstr_t *)calloc((size_t)bitstr_size(nbits), sizeof(bitstr_t))
  67
  68                                 /* allocate a bitstring on the stack */
  69 #define bit_decl(name, nbits) \
  70         ((name)[bitstr_size(nbits)])
  71
  72                                 /* is bit N of bitstring name set? */
  73 #define bit_test(name, bit) \
  74         ((name)[_bit_byte(bit)] & _bit_mask(bit))
  75
  76                                 /* set bit N of bitstring name */
  77 #define bit_set(name, bit) \
  78         ((name)[_bit_byte(bit)] |= _bit_mask(bit))
  79
  80                                 /* clear bit N of bitstring name */
  81 #define bit_clear(name, bit) \
  82         ((name)[_bit_byte(bit)] &= ~_bit_mask(bit))
  83
  84                                 /* clear bits start ... stop in bitstring */
  85 #define bit_nclear(name, start, stop) do { \
  86         register bitstr_t *_name = name; \
  87         register int _start = start, _stop = stop; \
  88         while (_start <= _stop) { \
  89                 bit_clear(_name, _start); \
  90                 _start++; \
  91                 } \
  92 } while(0)
  93
  94                                 /* set bits start ... stop in bitstring */
  95 #define bit_nset(name, start, stop) do { \
  96         register bitstr_t *_name = name; \
  97         register int _start = start, _stop = stop; \
  98         while (_start <= _stop) { \
  99                 bit_set(_name, _start); \
 100                 _start++; \
 101                 } \
 102 } while(0)
 103
 104                                 /* find first bit clear in name */
 105 #define bit_ffc(name, nbits, value) do { \
 106         register bitstr_t *_name = name; \
 107         register int _bit, _nbits = nbits, _value = -1; \
 108         for (_bit = 0; _bit < _nbits; ++_bit) \
 109                 if (!bit_test(_name, _bit)) { \
 110                         _value = _bit; \
 111                         break; \
 112                 } \
 113         *(value) = _value; \
 114 } while(0)
 115
 116                                 /* find first bit set in name */
 117 #define bit_ffs(name, nbits, value) do { \
 118         register bitstr_t *_name = name; \
 119         register int _bit, _nbits = nbits, _value = -1; \
 120         for (_bit = 0; _bit < _nbits; ++_bit) \
 121                 if (bit_test(_name, _bit)) { \
 122                         _value = _bit; \
 123                         break; \
 124                 } \
 125         *(value) = _value; \
 126 } while(0)
 127
 128 #endif /* !_BITSTRING_H_ */