bitstring.h revision 1.11
1/* $NetBSD: bitstring.h,v 1.11 2015/11/20 20:27:20 christos 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/* modified for SV/AT and bitstring bugfix by M.R.Murphy, 11oct91 41 * bitstr_size changed gratuitously, but shorter 42 * bit_alloc spelling error fixed 43 * the following were efficient, but didn't work, they've been made to 44 * work, but are no longer as efficient :-) 45 * bit_nclear, bit_nset, bit_ffc, bit_ffs 46 */ 47/* 48 * The comment above may or may not bear any resemblance to reality. 49 * This code has been maintained in a confusing way, with little 50 * information available on the provenance of much of it. "At least it 51 * works." 52 * /s/ Perry E. Metzger, 2 Feb 98 53 */ 54typedef unsigned char bitstr_t; 55 56/* internal macros */ 57 /* byte of the bitstring bit is in */ 58#define _bit_byte(bit) \ 59 (uint32_t)((bit) >> 3) 60 61 /* mask for the bit within its byte */ 62#define _bit_mask(bit) \ 63 (uint32_t)((1 << (uint32_t)((bit)&0x7))) 64 65/* external macros */ 66 /* bytes in a bitstring of nbits bits */ 67#define bitstr_size(nbits) \ 68 (size_t)((uint32_t)((nbits) + 7) >> 3) 69 70 /* allocate a bitstring */ 71#define bit_alloc(nbits) \ 72 calloc(bitstr_size(nbits), sizeof(bitstr_t)) 73 74 /* allocate a bitstring on the stack */ 75#define bit_decl(name, nbits) \ 76 ((name)[bitstr_size(nbits)]) 77 78 /* is bit N of bitstring name set? */ 79#define bit_test(name, bit) \ 80 /*LINTED bitwise on signed*/((name)[_bit_byte(bit)] & _bit_mask(bit)) 81 82 /* set bit N of bitstring name */ 83#define bit_set(name, bit) \ 84 /*LINTED bitwise on signed*/((name)[_bit_byte(bit)] |= _bit_mask(bit)) 85 86 /* clear bit N of bitstring name */ 87#define bit_clear(name, bit) \ 88 /*LINTED bitwise on signed*/((name)[_bit_byte(bit)] &= ~_bit_mask(bit)) 89 90 /* clear bits start ... stop in bitstring */ 91#define bit_nclear(name, start, stop) do { \ 92 bitstr_t *_name = name; \ 93 size_t _start = start, _stop = stop; \ 94 while (_start <= _stop) { \ 95 bit_clear(_name, _start); \ 96 _start++; \ 97 } \ 98} while(/*CONSTCOND*/0) 99 100 /* set bits start ... stop in bitstring */ 101#define bit_nset(name, start, stop) do { \ 102 bitstr_t *_name = name; \ 103 size_t _start = start, _stop = stop; \ 104 while (_start <= _stop) { \ 105 bit_set(_name, _start); \ 106 _start++; \ 107 } \ 108} while(/*CONSTCOND*/0) 109 110 /* find first bit clear in name */ 111#define bit_ffc(name, nbits, value) do { \ 112 bitstr_t *_name = name; \ 113 size_t _bit, _nbits = nbits; \ 114 int _value = -1; \ 115 for (_bit = 0; _bit < _nbits; ++_bit) \ 116 if (!bit_test(_name, _bit)) { \ 117 _value = _bit; \ 118 break; \ 119 } \ 120 *(value) = _value; \ 121} while(/*CONSTCOND*/0) 122 123 /* find first bit set in name */ 124#define bit_ffs(name, nbits, value) do { \ 125 bitstr_t *_name = name; \ 126 size_t _bit, _nbits = nbits; \ 127 int _value = -1; \ 128 for (_bit = 0; _bit < _nbits; ++_bit) \ 129 if (bit_test(_name, _bit)) { \ 130 _value = _bit; \ 131 break; \ 132 } \ 133 *(value) = _value; \ 134} while(/*CONSTCOND*/0) 135 136#endif /* !_BITSTRING_H_ */ 137