bitset.h revision 01e04c3f
1/* 2 * Mesa 3-D graphics library 3 * 4 * Copyright (C) 2006 Brian Paul All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the "Software"), 8 * to deal in the Software without restriction, including without limitation 9 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 10 * and/or sell copies of the Software, and to permit persons to whom the 11 * Software is furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included 14 * in all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 22 * OTHER DEALINGS IN THE SOFTWARE. 23 */ 24 25/** 26 * \file bitset.h 27 * \brief Bitset of arbitrary size definitions. 28 * \author Michal Krol 29 */ 30 31#ifndef BITSET_H 32#define BITSET_H 33 34#include "util/bitscan.h" 35#include "util/macros.h" 36 37/**************************************************************************** 38 * generic bitset implementation 39 */ 40 41#define BITSET_WORD unsigned int 42#define BITSET_WORDBITS (sizeof (BITSET_WORD) * 8) 43 44/* bitset declarations 45 */ 46#define BITSET_WORDS(bits) (((bits) + BITSET_WORDBITS - 1) / BITSET_WORDBITS) 47#define BITSET_DECLARE(name, bits) BITSET_WORD name[BITSET_WORDS(bits)] 48 49/* bitset operations 50 */ 51#define BITSET_COPY(x, y) memcpy( (x), (y), sizeof (x) ) 52#define BITSET_EQUAL(x, y) (memcmp( (x), (y), sizeof (x) ) == 0) 53#define BITSET_ZERO(x) memset( (x), 0, sizeof (x) ) 54#define BITSET_ONES(x) memset( (x), 0xff, sizeof (x) ) 55 56#define BITSET_BITWORD(b) ((b) / BITSET_WORDBITS) 57#define BITSET_BIT(b) (1u << ((b) % BITSET_WORDBITS)) 58 59/* single bit operations 60 */ 61#define BITSET_TEST(x, b) ((x)[BITSET_BITWORD(b)] & BITSET_BIT(b)) 62#define BITSET_SET(x, b) ((x)[BITSET_BITWORD(b)] |= BITSET_BIT(b)) 63#define BITSET_CLEAR(x, b) ((x)[BITSET_BITWORD(b)] &= ~BITSET_BIT(b)) 64 65#define BITSET_MASK(b) ((b) == BITSET_WORDBITS ? ~0 : BITSET_BIT(b) - 1) 66#define BITSET_RANGE(b, e) (BITSET_MASK((e) + 1) & ~BITSET_MASK(b)) 67 68/* bit range operations 69 */ 70#define BITSET_TEST_RANGE(x, b, e) \ 71 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \ 72 ((x)[BITSET_BITWORD(b)] & BITSET_RANGE(b, e)) : \ 73 (assert (!"BITSET_TEST_RANGE: bit range crosses word boundary"), 0)) 74#define BITSET_SET_RANGE(x, b, e) \ 75 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \ 76 ((x)[BITSET_BITWORD(b)] |= BITSET_RANGE(b, e)) : \ 77 (assert (!"BITSET_SET_RANGE: bit range crosses word boundary"), 0)) 78#define BITSET_CLEAR_RANGE(x, b, e) \ 79 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \ 80 ((x)[BITSET_BITWORD(b)] &= ~BITSET_RANGE(b, e)) : \ 81 (assert (!"BITSET_CLEAR_RANGE: bit range crosses word boundary"), 0)) 82 83/* Get first bit set in a bitset. 84 */ 85static inline int 86__bitset_ffs(const BITSET_WORD *x, int n) 87{ 88 int i; 89 90 for (i = 0; i < n; i++) { 91 if (x[i]) 92 return ffs(x[i]) + BITSET_WORDBITS * i; 93 } 94 95 return 0; 96} 97 98#define BITSET_FFS(x) __bitset_ffs(x, ARRAY_SIZE(x)) 99 100static inline unsigned 101__bitset_next_set(unsigned i, BITSET_WORD *tmp, 102 const BITSET_WORD *set, unsigned size) 103{ 104 unsigned bit, word; 105 106 /* NOTE: The initial conditions for this function are very specific. At 107 * the start of the loop, the tmp variable must be set to *set and the 108 * initial i value set to 0. This way, if there is a bit set in the first 109 * word, we ignore the i-value and just grab that bit (so 0 is ok, even 110 * though 0 may be returned). If the first word is 0, then the value of 111 * `word` will be 0 and we will go on to look at the second word. 112 */ 113 word = BITSET_BITWORD(i); 114 while (*tmp == 0) { 115 word++; 116 117 if (word >= BITSET_WORDS(size)) 118 return size; 119 120 *tmp = set[word]; 121 } 122 123 /* Find the next set bit in the non-zero word */ 124 bit = ffs(*tmp) - 1; 125 126 /* Unset the bit */ 127 *tmp &= ~(1ull << bit); 128 129 return word * BITSET_WORDBITS + bit; 130} 131 132#define BITSET_FOREACH_SET(__i, __tmp, __set, __size) \ 133 for (__tmp = *(__set), __i = 0; \ 134 (__i = __bitset_next_set(__i, &__tmp, __set, __size)) < __size;) 135 136#ifdef __cplusplus 137 138/** 139 * Simple C++ wrapper of a bitset type of static size, with value semantics 140 * and basic bitwise arithmetic operators. The operators defined below are 141 * expected to have the same semantics as the same operator applied to other 142 * fundamental integer types. T is the name of the struct to instantiate 143 * it as, and N is the number of bits in the bitset. 144 */ 145#define DECLARE_BITSET_T(T, N) struct T { \ 146 EXPLICIT_CONVERSION \ 147 operator bool() const \ 148 { \ 149 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \ 150 if (words[i]) \ 151 return true; \ 152 return false; \ 153 } \ 154 \ 155 T & \ 156 operator=(int x) \ 157 { \ 158 const T c = {{ (BITSET_WORD)x }}; \ 159 return *this = c; \ 160 } \ 161 \ 162 friend bool \ 163 operator==(const T &b, const T &c) \ 164 { \ 165 return BITSET_EQUAL(b.words, c.words); \ 166 } \ 167 \ 168 friend bool \ 169 operator!=(const T &b, const T &c) \ 170 { \ 171 return !(b == c); \ 172 } \ 173 \ 174 friend bool \ 175 operator==(const T &b, int x) \ 176 { \ 177 const T c = {{ (BITSET_WORD)x }}; \ 178 return b == c; \ 179 } \ 180 \ 181 friend bool \ 182 operator!=(const T &b, int x) \ 183 { \ 184 return !(b == x); \ 185 } \ 186 \ 187 friend T \ 188 operator~(const T &b) \ 189 { \ 190 T c; \ 191 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \ 192 c.words[i] = ~b.words[i]; \ 193 return c; \ 194 } \ 195 \ 196 T & \ 197 operator|=(const T &b) \ 198 { \ 199 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \ 200 words[i] |= b.words[i]; \ 201 return *this; \ 202 } \ 203 \ 204 friend T \ 205 operator|(const T &b, const T &c) \ 206 { \ 207 T d = b; \ 208 d |= c; \ 209 return d; \ 210 } \ 211 \ 212 T & \ 213 operator&=(const T &b) \ 214 { \ 215 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \ 216 words[i] &= b.words[i]; \ 217 return *this; \ 218 } \ 219 \ 220 friend T \ 221 operator&(const T &b, const T &c) \ 222 { \ 223 T d = b; \ 224 d &= c; \ 225 return d; \ 226 } \ 227 \ 228 bool \ 229 test(unsigned i) const \ 230 { \ 231 return BITSET_TEST(words, i); \ 232 } \ 233 \ 234 T & \ 235 set(unsigned i) \ 236 { \ 237 BITSET_SET(words, i); \ 238 return *this; \ 239 } \ 240 \ 241 T & \ 242 clear(unsigned i) \ 243 { \ 244 BITSET_CLEAR(words, i); \ 245 return *this; \ 246 } \ 247 \ 248 BITSET_WORD words[BITSET_WORDS(N)]; \ 249 } 250 251#endif 252 253#endif 254