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1 /*
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2 * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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342
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25 // Forward decl;
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26 class BitMapClosure;
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27
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342
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28 // Operations for bitmaps represented as arrays of unsigned integers.
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29 // Bit offsets are numbered from 0 to size-1.
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30
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31 class BitMap VALUE_OBJ_CLASS_SPEC {
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32 friend class BitMap2D;
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33
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34 public:
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35 typedef size_t idx_t; // Type used for bit and word indices.
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342
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36 typedef uintptr_t bm_word_t; // Element type of array that represents
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37 // the bitmap.
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38
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39 // Hints for range sizes.
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40 typedef enum {
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41 unknown_range, small_range, large_range
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42 } RangeSizeHint;
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43
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44 private:
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342
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45 bm_word_t* _map; // First word in bitmap
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46 idx_t _size; // Size of bitmap (in bits)
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47
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48 // Puts the given value at the given offset, using resize() to size
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49 // the bitmap appropriately if needed using factor-of-two expansion.
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50 void at_put_grow(idx_t index, bool value);
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51
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52 protected:
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53 // Return the position of bit within the word that contains it (e.g., if
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54 // bitmap words are 32 bits, return a number 0 <= n <= 31).
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55 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); }
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56
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57 // Return a mask that will select the specified bit, when applied to the word
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58 // containing the bit.
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342
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59 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); }
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60
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61 // Return the index of the word containing the specified bit.
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62 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; }
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63
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64 // Return the bit number of the first bit in the specified word.
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65 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; }
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66
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67 // Return the array of bitmap words, or a specific word from it.
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342
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68 bm_word_t* map() const { return _map; }
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69 bm_word_t map(idx_t word) const { return _map[word]; }
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70
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71 // Return a pointer to the word containing the specified bit.
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342
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72 bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); }
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73
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74 // Set a word to a specified value or to all ones; clear a word.
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342
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75 void set_word (idx_t word, bm_word_t val) { _map[word] = val; }
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76 void set_word (idx_t word) { set_word(word, ~(uintptr_t)0); }
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77 void clear_word(idx_t word) { _map[word] = 0; }
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78
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79 // Utilities for ranges of bits. Ranges are half-open [beg, end).
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80
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81 // Ranges within a single word.
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342
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82 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const;
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83 void set_range_within_word (idx_t beg, idx_t end);
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84 void clear_range_within_word (idx_t beg, idx_t end);
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85 void par_put_range_within_word (idx_t beg, idx_t end, bool value);
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86
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87 // Ranges spanning entire words.
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342
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88 void set_range_of_words (idx_t beg, idx_t end);
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89 void clear_range_of_words (idx_t beg, idx_t end);
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90 void set_large_range_of_words (idx_t beg, idx_t end);
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91 void clear_large_range_of_words (idx_t beg, idx_t end);
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92
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93 // The index of the first full word in a range.
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342
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94 idx_t word_index_round_up(idx_t bit) const;
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95
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96 // Verification, statistics.
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342
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97 void verify_index(idx_t index) const;
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98 void verify_range(idx_t beg_index, idx_t end_index) const;
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99
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342
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100 static idx_t* _pop_count_table;
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101 static void init_pop_count_table();
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102 static idx_t num_set_bits(bm_word_t w);
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103 static idx_t num_set_bits_from_table(unsigned char c);
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104
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105 public:
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106
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107 // Constructs a bitmap with no map, and size 0.
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108 BitMap() : _map(NULL), _size(0) {}
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109
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342
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110 // Constructs a bitmap with the given map and size.
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111 BitMap(bm_word_t* map, idx_t size_in_bits);
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112
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342
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113 // Constructs an empty bitmap of the given size (that is, this clears the
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114 // new bitmap). Allocates the map array in resource area if
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115 // "in_resource_area" is true, else in the C heap.
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116 BitMap(idx_t size_in_bits, bool in_resource_area = true);
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117
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342
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118 // Set the map and size.
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119 void set_map(bm_word_t* map) { _map = map; }
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120 void set_size(idx_t size_in_bits) { _size = size_in_bits; }
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121
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342
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122 // Allocates necessary data structure, either in the resource area
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123 // or in the C heap, as indicated by "in_resource_area."
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124 // Preserves state currently in bit map by copying data.
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125 // Zeros any newly-addressable bits.
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342
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126 // If "in_resource_area" is false, frees the current map.
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127 // (Note that this assumes that all calls to "resize" on the same BitMap
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128 // use the same value for "in_resource_area".)
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129 void resize(idx_t size_in_bits, bool in_resource_area = true);
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130
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131 // Accessing
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132 idx_t size() const { return _size; }
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133 idx_t size_in_words() const {
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134 return word_index(size() + BitsPerWord - 1);
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135 }
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136
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137 bool at(idx_t index) const {
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138 verify_index(index);
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139 return (*word_addr(index) & bit_mask(index)) != 0;
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140 }
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141
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142 // Align bit index up or down to the next bitmap word boundary, or check
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143 // alignment.
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144 static idx_t word_align_up(idx_t bit) {
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145 return align_size_up(bit, BitsPerWord);
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146 }
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147 static idx_t word_align_down(idx_t bit) {
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148 return align_size_down(bit, BitsPerWord);
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149 }
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150 static bool is_word_aligned(idx_t bit) {
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151 return word_align_up(bit) == bit;
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152 }
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153
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154 // Set or clear the specified bit.
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155 inline void set_bit(idx_t bit);
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342
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156 void clear_bit(idx_t bit);
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157
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158 // Atomically set or clear the specified bit.
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342
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159 bool par_set_bit(idx_t bit);
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160 bool par_clear_bit(idx_t bit);
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161
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162 // Put the given value at the given offset. The parallel version
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163 // will CAS the value into the bitmap and is quite a bit slower.
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164 // The parallel version also returns a value indicating if the
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165 // calling thread was the one that changed the value of the bit.
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166 void at_put(idx_t index, bool value);
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167 bool par_at_put(idx_t index, bool value);
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168
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169 // Update a range of bits. Ranges are half-open [beg, end).
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170 void set_range (idx_t beg, idx_t end);
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171 void clear_range (idx_t beg, idx_t end);
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172 void set_large_range (idx_t beg, idx_t end);
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173 void clear_large_range (idx_t beg, idx_t end);
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174 void at_put_range(idx_t beg, idx_t end, bool value);
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175 void par_at_put_range(idx_t beg, idx_t end, bool value);
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176 void at_put_large_range(idx_t beg, idx_t end, bool value);
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177 void par_at_put_large_range(idx_t beg, idx_t end, bool value);
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178
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179 // Update a range of bits, using a hint about the size. Currently only
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180 // inlines the predominant case of a 1-bit range. Works best when hint is a
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181 // compile-time constant.
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342
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182 void set_range(idx_t beg, idx_t end, RangeSizeHint hint);
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183 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint);
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184 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint);
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185 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint);
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186
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187 // It performs the union operation between subsets of equal length
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188 // of two bitmaps (the target bitmap of the method and the
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189 // from_bitmap) and stores the result to the target bitmap. The
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190 // from_start_index represents the first bit index of the subrange
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191 // of the from_bitmap. The to_start_index is the equivalent of the
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192 // target bitmap. Both indexes should be word-aligned, i.e. they
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193 // should correspond to the first bit on a bitmap word (it's up to
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194 // the caller to ensure this; the method does check it). The length
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195 // of the subset is specified with word_num and it is in number of
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196 // bitmap words. The caller should ensure that this is at least 2
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197 // (smaller ranges are not support to save extra checks). Again,
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198 // this is checked in the method.
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199 //
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200 // Atomicity concerns: it is assumed that any contention on the
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201 // target bitmap with other threads will happen on the first and
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202 // last words; the ones in between will be "owned" exclusively by
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203 // the calling thread and, in fact, they will already be 0. So, the
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204 // method performs a CAS on the first word, copies the next
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205 // word_num-2 words, and finally performs a CAS on the last word.
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206 void mostly_disjoint_range_union(BitMap* from_bitmap,
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207 idx_t from_start_index,
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208 idx_t to_start_index,
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209 size_t word_num);
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210
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211
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212 // Clearing
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213 void clear_large();
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342
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214 inline void clear();
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215
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342
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216 // Iteration support. Returns "true" if the iteration completed, false
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217 // if the iteration terminated early (because the closure "blk" returned
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218 // false).
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219 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex);
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220 bool iterate(BitMapClosure* blk) {
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221 // call the version that takes an interval
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222 return iterate(blk, 0, size());
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223 }
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224
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342
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225 // Looking for 1's and 0's at indices equal to or greater than "l_index",
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226 // stopping if none has been found before "r_index", and returning
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227 // "r_index" (which must be at most "size") in that case.
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228 idx_t get_next_one_offset_inline (idx_t l_index, idx_t r_index) const;
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229 idx_t get_next_zero_offset_inline(idx_t l_index, idx_t r_index) const;
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230
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231 // Like "get_next_one_offset_inline", except requires that "r_index" is
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232 // aligned to bitsizeof(bm_word_t).
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233 idx_t get_next_one_offset_inline_aligned_right(idx_t l_index,
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234 idx_t r_index) const;
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235
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236 // Non-inline versionsof the above.
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237 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const;
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238 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const;
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239
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240 idx_t get_next_one_offset(idx_t offset) const {
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241 return get_next_one_offset(offset, size());
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242 }
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243 idx_t get_next_zero_offset(idx_t offset) const {
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244 return get_next_zero_offset(offset, size());
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245 }
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246
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342
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247 // Returns the number of bits set in the bitmap.
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248 idx_t count_one_bits() const;
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249
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250 // Set operations.
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251 void set_union(BitMap bits);
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252 void set_difference(BitMap bits);
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253 void set_intersection(BitMap bits);
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254 // Returns true iff "this" is a superset of "bits".
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255 bool contains(const BitMap bits) const;
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256 // Returns true iff "this and "bits" have a non-empty intersection.
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257 bool intersects(const BitMap bits) const;
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258
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259 // Returns result of whether this map changed
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260 // during the operation
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261 bool set_union_with_result(BitMap bits);
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262 bool set_difference_with_result(BitMap bits);
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263 bool set_intersection_with_result(BitMap bits);
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264
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342
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265 // Requires the submap of "bits" starting at offset to be at least as
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266 // large as "this". Modifies "this" to be the intersection of its
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267 // current contents and the submap of "bits" starting at "offset" of the
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268 // same length as "this."
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269 // (For expedience, currently requires the offset to be aligned to the
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270 // bitsize of a uintptr_t. This should go away in the future though it
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271 // will probably remain a good case to optimize.)
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272 void set_intersection_at_offset(BitMap bits, idx_t offset);
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273
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274 void set_from(BitMap bits);
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275
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276 bool is_same(BitMap bits);
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277
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278 // Test if all bits are set or cleared
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279 bool is_full() const;
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280 bool is_empty() const;
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281
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282
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283 #ifndef PRODUCT
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284 public:
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285 // Printing
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286 void print_on(outputStream* st) const;
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287 #endif
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288 };
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289
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290
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291 // Convenience class wrapping BitMap which provides multiple bits per slot.
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292 class BitMap2D VALUE_OBJ_CLASS_SPEC {
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293 public:
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342
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294 typedef BitMap::idx_t idx_t; // Type used for bit and word indices.
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295 typedef BitMap::bm_word_t bm_word_t; // Element type of array that
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296 // represents the bitmap.
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297 private:
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298 BitMap _map;
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299 idx_t _bits_per_slot;
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300
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301 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const {
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302 return slot_index * _bits_per_slot + bit_within_slot_index;
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303 }
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304
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305 void verify_bit_within_slot_index(idx_t index) const {
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306 assert(index < _bits_per_slot, "bit_within_slot index out of bounds");
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307 }
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308
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309 public:
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310 // Construction. bits_per_slot must be greater than 0.
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311 BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot);
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312
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313 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0.
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314 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot);
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315
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316 idx_t size_in_bits() {
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317 return _map.size();
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318 }
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319
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320 // Returns number of full slots that have been allocated
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321 idx_t size_in_slots() {
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322 // Round down
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323 return _map.size() / _bits_per_slot;
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324 }
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325
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326 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index) {
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327 verify_bit_within_slot_index(bit_within_slot_index);
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328 return (bit_index(slot_index, bit_within_slot_index) < size_in_bits());
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329 }
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330
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331 bool at(idx_t slot_index, idx_t bit_within_slot_index) const {
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332 verify_bit_within_slot_index(bit_within_slot_index);
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333 return _map.at(bit_index(slot_index, bit_within_slot_index));
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334 }
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335
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336 void set_bit(idx_t slot_index, idx_t bit_within_slot_index) {
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337 verify_bit_within_slot_index(bit_within_slot_index);
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338 _map.set_bit(bit_index(slot_index, bit_within_slot_index));
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339 }
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340
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341 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index) {
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342 verify_bit_within_slot_index(bit_within_slot_index);
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343 _map.clear_bit(bit_index(slot_index, bit_within_slot_index));
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344 }
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345
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346 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
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347 verify_bit_within_slot_index(bit_within_slot_index);
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348 _map.at_put(bit_index(slot_index, bit_within_slot_index), value);
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349 }
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350
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351 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
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352 verify_bit_within_slot_index(bit_within_slot_index);
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353 _map.at_put_grow(bit_index(slot_index, bit_within_slot_index), value);
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354 }
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355
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342
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356 void clear();
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357 };
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358
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342
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359 // Closure for iterating over BitMaps
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360
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342
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361 class BitMapClosure VALUE_OBJ_CLASS_SPEC {
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362 public:
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363 // Callback when bit in map is set. Should normally return "true";
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364 // return of false indicates that the bitmap iteration should terminate.
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365 virtual bool do_bit(BitMap::idx_t offset) = 0;
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366 };
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