1 /* $NetBSD: bitstring.h,v 1.15 2024/05/12 10:41:23 rillig 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 */ 54 typedef 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*/ \ 85 ((name)[_bit_byte(bit)] = \ 86 (unsigned char)(_bit_mask(bit) | (name)[_bit_byte(bit)])) 87 88 /* clear bit N of bitstring name */ 89 #define bit_clear(name, bit) \ 90 /*LINTED bitwise on signed*/ \ 91 ((name)[_bit_byte(bit)] &= (unsigned char)~_bit_mask(bit)) 92 93 /* clear bits start ... stop in bitstring */ 94 #define bit_nclear(name, start, stop) do { \ 95 bitstr_t *_name = name; \ 96 size_t _start = start, _stop = stop; \ 97 while (_start <= _stop) { \ 98 bit_clear(_name, _start); \ 99 _start++; \ 100 } \ 101 } while (0) 102 103 /* set bits start ... stop in bitstring */ 104 #define bit_nset(name, start, stop) do { \ 105 bitstr_t *_name = name; \ 106 size_t _start = start, _stop = stop; \ 107 while (_start <= _stop) { \ 108 bit_set(_name, _start); \ 109 _start++; \ 110 } \ 111 } while (0) 112 113 /* find first bit clear in name */ 114 #define bit_ffc(name, nbits, value) do { \ 115 const bitstr_t *_name = name; \ 116 size_t _bit, _nbits = nbits; \ 117 int _value = -1; \ 118 for (_bit = 0; _bit < _nbits; ++_bit) \ 119 if (!bit_test(_name, _bit)) { \ 120 _value = _bit; \ 121 break; \ 122 } \ 123 *(value) = _value; \ 124 } while (0) 125 126 /* find first bit set in name */ 127 #define bit_ffs(name, nbits, value) do { \ 128 const bitstr_t *_name = name; \ 129 size_t _bit, _nbits = nbits; \ 130 int _value = -1; \ 131 for (_bit = 0; _bit < _nbits; ++_bit) \ 132 if (bit_test(_name, _bit)) { \ 133 _value = _bit; \ 134 break; \ 135 } \ 136 *(value) = _value; \ 137 } while (0) 138 139 #endif /* !_BITSTRING_H_ */ 140