bitMap.hpp revision 1472:c18cbe5936b8
1/* 2 * Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25// Forward decl; 26class BitMapClosure; 27 28// Operations for bitmaps represented as arrays of unsigned integers. 29// Bit offsets are numbered from 0 to size-1. 30 31class BitMap VALUE_OBJ_CLASS_SPEC { 32 friend class BitMap2D; 33 34 public: 35 typedef size_t idx_t; // Type used for bit and word indices. 36 typedef uintptr_t bm_word_t; // Element type of array that represents 37 // the bitmap. 38 39 // Hints for range sizes. 40 typedef enum { 41 unknown_range, small_range, large_range 42 } RangeSizeHint; 43 44 private: 45 bm_word_t* _map; // First word in bitmap 46 idx_t _size; // Size of bitmap (in bits) 47 48 // Puts the given value at the given offset, using resize() to size 49 // the bitmap appropriately if needed using factor-of-two expansion. 50 void at_put_grow(idx_t index, bool value); 51 52 protected: 53 // Return the position of bit within the word that contains it (e.g., if 54 // bitmap words are 32 bits, return a number 0 <= n <= 31). 55 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); } 56 57 // Return a mask that will select the specified bit, when applied to the word 58 // containing the bit. 59 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); } 60 61 // Return the index of the word containing the specified bit. 62 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; } 63 64 // Return the bit number of the first bit in the specified word. 65 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; } 66 67 // Return the array of bitmap words, or a specific word from it. 68 bm_word_t* map() const { return _map; } 69 bm_word_t map(idx_t word) const { return _map[word]; } 70 71 // Return a pointer to the word containing the specified bit. 72 bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); } 73 74 // Set a word to a specified value or to all ones; clear a word. 75 void set_word (idx_t word, bm_word_t val) { _map[word] = val; } 76 void set_word (idx_t word) { set_word(word, ~(uintptr_t)0); } 77 void clear_word(idx_t word) { _map[word] = 0; } 78 79 // Utilities for ranges of bits. Ranges are half-open [beg, end). 80 81 // Ranges within a single word. 82 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const; 83 void set_range_within_word (idx_t beg, idx_t end); 84 void clear_range_within_word (idx_t beg, idx_t end); 85 void par_put_range_within_word (idx_t beg, idx_t end, bool value); 86 87 // Ranges spanning entire words. 88 void set_range_of_words (idx_t beg, idx_t end); 89 void clear_range_of_words (idx_t beg, idx_t end); 90 void set_large_range_of_words (idx_t beg, idx_t end); 91 void clear_large_range_of_words (idx_t beg, idx_t end); 92 93 // The index of the first full word in a range. 94 idx_t word_index_round_up(idx_t bit) const; 95 96 // Verification. 97 inline void verify_index(idx_t index) const NOT_DEBUG_RETURN; 98 inline void verify_range(idx_t beg_index, idx_t end_index) const 99 NOT_DEBUG_RETURN; 100 101 // Statistics. 102 static idx_t* _pop_count_table; 103 static void init_pop_count_table(); 104 static idx_t num_set_bits(bm_word_t w); 105 static idx_t num_set_bits_from_table(unsigned char c); 106 107 public: 108 109 // Constructs a bitmap with no map, and size 0. 110 BitMap() : _map(NULL), _size(0) {} 111 112 // Constructs a bitmap with the given map and size. 113 BitMap(bm_word_t* map, idx_t size_in_bits); 114 115 // Constructs an empty bitmap of the given size (that is, this clears the 116 // new bitmap). Allocates the map array in resource area if 117 // "in_resource_area" is true, else in the C heap. 118 BitMap(idx_t size_in_bits, bool in_resource_area = true); 119 120 // Set the map and size. 121 void set_map(bm_word_t* map) { _map = map; } 122 void set_size(idx_t size_in_bits) { _size = size_in_bits; } 123 124 // Allocates necessary data structure, either in the resource area 125 // or in the C heap, as indicated by "in_resource_area." 126 // Preserves state currently in bit map by copying data. 127 // Zeros any newly-addressable bits. 128 // If "in_resource_area" is false, frees the current map. 129 // (Note that this assumes that all calls to "resize" on the same BitMap 130 // use the same value for "in_resource_area".) 131 void resize(idx_t size_in_bits, bool in_resource_area = true); 132 133 // Accessing 134 idx_t size() const { return _size; } 135 idx_t size_in_words() const { 136 return word_index(size() + BitsPerWord - 1); 137 } 138 139 bool at(idx_t index) const { 140 verify_index(index); 141 return (*word_addr(index) & bit_mask(index)) != 0; 142 } 143 144 // Align bit index up or down to the next bitmap word boundary, or check 145 // alignment. 146 static idx_t word_align_up(idx_t bit) { 147 return align_size_up(bit, BitsPerWord); 148 } 149 static idx_t word_align_down(idx_t bit) { 150 return align_size_down(bit, BitsPerWord); 151 } 152 static bool is_word_aligned(idx_t bit) { 153 return word_align_up(bit) == bit; 154 } 155 156 // Set or clear the specified bit. 157 inline void set_bit(idx_t bit); 158 void clear_bit(idx_t bit); 159 160 // Atomically set or clear the specified bit. 161 bool par_set_bit(idx_t bit); 162 bool par_clear_bit(idx_t bit); 163 164 // Put the given value at the given offset. The parallel version 165 // will CAS the value into the bitmap and is quite a bit slower. 166 // The parallel version also returns a value indicating if the 167 // calling thread was the one that changed the value of the bit. 168 void at_put(idx_t index, bool value); 169 bool par_at_put(idx_t index, bool value); 170 171 // Update a range of bits. Ranges are half-open [beg, end). 172 void set_range (idx_t beg, idx_t end); 173 void clear_range (idx_t beg, idx_t end); 174 void set_large_range (idx_t beg, idx_t end); 175 void clear_large_range (idx_t beg, idx_t end); 176 void at_put_range(idx_t beg, idx_t end, bool value); 177 void par_at_put_range(idx_t beg, idx_t end, bool value); 178 void at_put_large_range(idx_t beg, idx_t end, bool value); 179 void par_at_put_large_range(idx_t beg, idx_t end, bool value); 180 181 // Update a range of bits, using a hint about the size. Currently only 182 // inlines the predominant case of a 1-bit range. Works best when hint is a 183 // compile-time constant. 184 void set_range(idx_t beg, idx_t end, RangeSizeHint hint); 185 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint); 186 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint); 187 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint); 188 189 // It performs the union operation between subsets of equal length 190 // of two bitmaps (the target bitmap of the method and the 191 // from_bitmap) and stores the result to the target bitmap. The 192 // from_start_index represents the first bit index of the subrange 193 // of the from_bitmap. The to_start_index is the equivalent of the 194 // target bitmap. Both indexes should be word-aligned, i.e. they 195 // should correspond to the first bit on a bitmap word (it's up to 196 // the caller to ensure this; the method does check it). The length 197 // of the subset is specified with word_num and it is in number of 198 // bitmap words. The caller should ensure that this is at least 2 199 // (smaller ranges are not support to save extra checks). Again, 200 // this is checked in the method. 201 // 202 // Atomicity concerns: it is assumed that any contention on the 203 // target bitmap with other threads will happen on the first and 204 // last words; the ones in between will be "owned" exclusively by 205 // the calling thread and, in fact, they will already be 0. So, the 206 // method performs a CAS on the first word, copies the next 207 // word_num-2 words, and finally performs a CAS on the last word. 208 void mostly_disjoint_range_union(BitMap* from_bitmap, 209 idx_t from_start_index, 210 idx_t to_start_index, 211 size_t word_num); 212 213 214 // Clearing 215 void clear_large(); 216 inline void clear(); 217 218 // Iteration support. Returns "true" if the iteration completed, false 219 // if the iteration terminated early (because the closure "blk" returned 220 // false). 221 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex); 222 bool iterate(BitMapClosure* blk) { 223 // call the version that takes an interval 224 return iterate(blk, 0, size()); 225 } 226 227 // Looking for 1's and 0's at indices equal to or greater than "l_index", 228 // stopping if none has been found before "r_index", and returning 229 // "r_index" (which must be at most "size") in that case. 230 idx_t get_next_one_offset_inline (idx_t l_index, idx_t r_index) const; 231 idx_t get_next_zero_offset_inline(idx_t l_index, idx_t r_index) const; 232 233 // Like "get_next_one_offset_inline", except requires that "r_index" is 234 // aligned to bitsizeof(bm_word_t). 235 idx_t get_next_one_offset_inline_aligned_right(idx_t l_index, 236 idx_t r_index) const; 237 238 // Non-inline versionsof the above. 239 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const; 240 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const; 241 242 idx_t get_next_one_offset(idx_t offset) const { 243 return get_next_one_offset(offset, size()); 244 } 245 idx_t get_next_zero_offset(idx_t offset) const { 246 return get_next_zero_offset(offset, size()); 247 } 248 249 // Returns the number of bits set in the bitmap. 250 idx_t count_one_bits() const; 251 252 // Set operations. 253 void set_union(BitMap bits); 254 void set_difference(BitMap bits); 255 void set_intersection(BitMap bits); 256 // Returns true iff "this" is a superset of "bits". 257 bool contains(const BitMap bits) const; 258 // Returns true iff "this and "bits" have a non-empty intersection. 259 bool intersects(const BitMap bits) const; 260 261 // Returns result of whether this map changed 262 // during the operation 263 bool set_union_with_result(BitMap bits); 264 bool set_difference_with_result(BitMap bits); 265 bool set_intersection_with_result(BitMap bits); 266 267 // Requires the submap of "bits" starting at offset to be at least as 268 // large as "this". Modifies "this" to be the intersection of its 269 // current contents and the submap of "bits" starting at "offset" of the 270 // same length as "this." 271 // (For expedience, currently requires the offset to be aligned to the 272 // bitsize of a uintptr_t. This should go away in the future though it 273 // will probably remain a good case to optimize.) 274 void set_intersection_at_offset(BitMap bits, idx_t offset); 275 276 void set_from(BitMap bits); 277 278 bool is_same(BitMap bits); 279 280 // Test if all bits are set or cleared 281 bool is_full() const; 282 bool is_empty() const; 283 284 285#ifndef PRODUCT 286 public: 287 // Printing 288 void print_on(outputStream* st) const; 289#endif 290}; 291 292// Convenience class wrapping BitMap which provides multiple bits per slot. 293class BitMap2D VALUE_OBJ_CLASS_SPEC { 294 public: 295 typedef BitMap::idx_t idx_t; // Type used for bit and word indices. 296 typedef BitMap::bm_word_t bm_word_t; // Element type of array that 297 // represents the bitmap. 298 private: 299 BitMap _map; 300 idx_t _bits_per_slot; 301 302 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const { 303 return slot_index * _bits_per_slot + bit_within_slot_index; 304 } 305 306 void verify_bit_within_slot_index(idx_t index) const { 307 assert(index < _bits_per_slot, "bit_within_slot index out of bounds"); 308 } 309 310 public: 311 // Construction. bits_per_slot must be greater than 0. 312 BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot); 313 314 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0. 315 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot); 316 317 idx_t size_in_bits() { 318 return _map.size(); 319 } 320 321 // Returns number of full slots that have been allocated 322 idx_t size_in_slots() { 323 // Round down 324 return _map.size() / _bits_per_slot; 325 } 326 327 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index) { 328 verify_bit_within_slot_index(bit_within_slot_index); 329 return (bit_index(slot_index, bit_within_slot_index) < size_in_bits()); 330 } 331 332 bool at(idx_t slot_index, idx_t bit_within_slot_index) const { 333 verify_bit_within_slot_index(bit_within_slot_index); 334 return _map.at(bit_index(slot_index, bit_within_slot_index)); 335 } 336 337 void set_bit(idx_t slot_index, idx_t bit_within_slot_index) { 338 verify_bit_within_slot_index(bit_within_slot_index); 339 _map.set_bit(bit_index(slot_index, bit_within_slot_index)); 340 } 341 342 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index) { 343 verify_bit_within_slot_index(bit_within_slot_index); 344 _map.clear_bit(bit_index(slot_index, bit_within_slot_index)); 345 } 346 347 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value) { 348 verify_bit_within_slot_index(bit_within_slot_index); 349 _map.at_put(bit_index(slot_index, bit_within_slot_index), value); 350 } 351 352 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value) { 353 verify_bit_within_slot_index(bit_within_slot_index); 354 _map.at_put_grow(bit_index(slot_index, bit_within_slot_index), value); 355 } 356 357 void clear(); 358}; 359 360// Closure for iterating over BitMaps 361 362class BitMapClosure VALUE_OBJ_CLASS_SPEC { 363 public: 364 // Callback when bit in map is set. Should normally return "true"; 365 // return of false indicates that the bitmap iteration should terminate. 366 virtual bool do_bit(BitMap::idx_t offset) = 0; 367}; 368