1 /* 2 * Copyright (c) 1989 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Paul Vixie. 7 * 8 * %sccs.include.redist.c% 9 * 10 * @(#)bitstring.h 5.5 (Berkeley) 04/03/91 11 */ 12 13 #ifndef _BITSTRING_H_ 14 #define _BITSTRING_H_ 15 16 typedef unsigned char bitstr_t; 17 18 /* internal macros */ 19 /* byte of the bitstring bit is in */ 20 #define _bit_byte(bit) \ 21 ((bit) >> 3) 22 23 /* mask for the bit within its byte */ 24 #define _bit_mask(bit) \ 25 (1 << ((bit)&0x7)) 26 27 /* external macros */ 28 /* bytes in a bitstring of nbits bits */ 29 #define bitstr_size(nbits) \ 30 ((((nbits) - 1) >> 3) + 1) 31 32 /* allocate a bitstring */ 33 #define bit_alloc(nbits) \ 34 (bitstr_t *)calloc(1, \ 35 (unsigned int)_bitstr_size(nbits) * sizeof(bitstr_t)) 36 37 /* allocate a bitstring on the stack */ 38 #define bit_decl(name, nbits) \ 39 (name)[bitstr_size(nbits)] 40 41 /* is bit N of bitstring name set? */ 42 #define bit_test(name, bit) \ 43 ((name)[_bit_byte(bit)] & _bit_mask(bit)) 44 45 /* set bit N of bitstring name */ 46 #define bit_set(name, bit) \ 47 (name)[_bit_byte(bit)] |= _bit_mask(bit) 48 49 /* clear bit N of bitstring name */ 50 #define bit_clear(name, bit) \ 51 (name)[_bit_byte(bit)] &= ~_bit_mask(bit) 52 53 /* clear bits start ... stop in bitstring */ 54 #define bit_nclear(name, start, stop) { \ 55 register bitstr_t *_name = name; \ 56 register int _start = start, _stop = stop; \ 57 register int _startbyte = _bit_byte(_start); \ 58 register int _stopbyte = _bit_byte(_stop); \ 59 _name[_startbyte] &= 0xff >> (8 - (_start&0x7)); \ 60 while (++_startbyte < _stopbyte) \ 61 _name[_startbyte] = 0; \ 62 _name[_stopbyte] &= 0xff << ((_stop&0x7) + 1); \ 63 } 64 65 /* set bits start ... stop in bitstring */ 66 #define bit_nset(name, start, stop) { \ 67 register bitstr_t *_name = name; \ 68 register int _start = start, _stop = stop; \ 69 register int _startbyte = _bit_byte(_start); \ 70 register int _stopbyte = _bit_byte(_stop); \ 71 _name[_startbyte] |= 0xff << ((start)&0x7); \ 72 while (++_startbyte < _stopbyte) \ 73 _name[_startbyte] = 0xff; \ 74 _name[_stopbyte] |= 0xff >> (7 - (_stop&0x7)); \ 75 } 76 77 /* find first bit clear in name */ 78 #define bit_ffc(name, nbits, value) { \ 79 register bitstr_t *_name = name; \ 80 register int _byte, _nbits = nbits; \ 81 register int _stopbyte = _bit_byte(_nbits), _value = -1; \ 82 for (_byte = 0; _byte <= _stopbyte; ++_byte) \ 83 if (_name[_byte] != 0xff) { \ 84 _value = _byte << 3; \ 85 for (_stopbyte = _name[_byte]; (_stopbyte&0x1); \ 86 ++_value, _stopbyte >>= 1); \ 87 break; \ 88 } \ 89 *(value) = _value; \ 90 } 91 92 /* find first bit set in name */ 93 #define bit_ffs(name, nbits, value) { \ 94 register bitstr_t *_name = name; \ 95 register int _byte, _nbits = nbits; \ 96 register int _stopbyte = _bit_byte(_nbits), _value = -1; \ 97 for (_byte = 0; _byte <= _stopbyte; ++_byte) \ 98 if (_name[_byte]) { \ 99 _value = _byte << 3; \ 100 for (_stopbyte = _name[_byte]; !(_stopbyte&0x1); \ 101 ++_value, _stopbyte >>= 1); \ 102 break; \ 103 } \ 104 *(value) = _value; \ 105 } 106 107 #endif /* !_BITSTRING_H_ */ 108